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Oral squamous cell carcinoma (OSCC) is a prevalent and aggressive malignancy, with metastasis being the leading cause of death in patients. Unfortunately, therapeutic options for metastatic OSCC remain limited. Peptidylarginine deiminases (PADI) are implicated in various tumorigenesis and metastasis processes across multiple cancers. However, the role of PADI2, a type of PADI, in OSCC is not well understood. This study aimed to explore the impact of PADI2 on epithelial-mesenchymal transition (EMT), angiogenesis, and OSCC metastasis. The effect of PADI2 on EMT was evaluated using cell lines by Western blot analysis with shRNA targeting PADI2. In addition, the selective PADI2 inhibitor AFM32a was used to assess the effect of PADI2 on cancer metastasis and angiogenesis in animal models. Our findings indicated that PADI2 expression correlated with EMT changes, and PADI2 knockdown reversed these changes, reducing cell proliferation, cell migration, and invasion. PADI2 inhibition also diminished tube formation in HUVECs and decreased secretion of angiogenesis-related chemokines CCL3, CCL5 and CCL20. In a mouse model, AFM32a markedly reduced lung metastasis and production of CCL3 and CCL5. Our in vitro and in vivo studies suggested inhibiting PADI2 could prevent OSCC metastasis by impeding EMT and angiogenesis via AKT/mTOR signaling pathway. These results highlight PADI2 as a potential therapeutic target for combating OSCC metastasis., Competing Interests: Declarations. Ethical approval: Animal protocols obeyed the instructions of the Institutional Animal Care and Use Committee of Dalin Tzu Chi Hospital (IACUC no.112001). Competing interests: The authors declare no competing interests., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

Regulatory T cells (Treg) are important players in the tumor microenvironment. However, the mechanisms behind their immunosuppressive effects are poorly understood. We found that CCR6-CCL20 activity in tumor-infiltrating Tregs is associated with greater glycolytic activity and ablation of Ccr6 reduced glycolysis and lactic acid production while increasing compensatory glutamine metabolism. Immunosuppressive activity toward CD8+ T cells was abrogated in Ccr6-/- Tregs due to reduction in activation-induced glycolysis. Furthermore, Ccr6-/- mice exhibited improved survival across multiple tumor models compared to wild-type mice and Treg and CD8+ T-cell depletion abrogated the improvement. In addition, Ccr6 ablation further promoted the efficacy of anti-PD-1 therapy in a preclinical glioma model. Follow-up knockdown of Ccl20 with siRNA also demonstrated improvement in antitumor efficacy. Our results unveil CCR6 as a marker and regulator of Treg-induced immunosuppression and identify approaches to target the metabolic determinants of Treg immunosuppressive activity., (©2024 American Association for Cancer Research.)

Objective: This study was performed to explore the clinical significance of the expression of human beta-defensin 2 (HBD-2) and chemokine ligand 1/2 (CXCL-1/2) in psoriasis vulgaris., Methods: This study retrospectively included the study group (n = 160) and control group (n = 100) for analysis. The levels of inflammatory indicators, blood biochemical indicators, and immune indicators using ELISA. The psoriasis area and severity index (PASI) was used to evaluate disease severity. Levels of HBD-2, CXCL-1, CXCL-2 and CCL20 were determined by RT-PCR. The correlations of HBD-2, CXCL-1 and CXCL-2 levels with CCL20 and PASI scores were analyzed. The diagnostic value of HBD-2, CXCL-1 and CXCL-2 in psoriasis vulgaris was analyzed by ROC curve., Results: HBD-2, CXCL-1 and CXCL-2 were highly expressed in the lesions of psoriasis vulgaris patients, and were positively correlated with CCL20 and PASI score. HBD-2, CXCL-1 and CXCL-2 alone or in combination had high diagnostic value for psoriasis vulgaris and severe psoriasis, and the combined diagnostic value of the three was higher than that of a single indicator., Conclusion: HBD-2, CXCL-1, and CXCL-2 levels are closely related to the severity of psoriasis vulgaris and can effectively diagnose the occurrence and progression of psoriasis vulgaris.

The correlation between the CCL20/CCR6 axis and autoimmune and non-autoimmune disorders is widely recognized. Inhibition of the CCL20-dependent cell migration represents therefore a promising approach for the treatment of many diseases, such as inflammatory bowel diseases and colorectal cancer. We report herein our efforts to explore the biologically relevant chemical space around the benzofuran scaffold of MR120, a modulator of the CCL20/CCR6 axis previously discovered by our group. A functional screening allowed us to identify C4 and C5-substituted derivatives as the most effective inhibitors of the CCL20-induced chemotaxis of human peripheral blood mononuclear cells (PBMC). Moreover, selected compounds (16 e and 24 b) also proved to potently inhibit the growth of different colon cancer cell lines, with cytotoxic/cytostatic and antiproliferative activity., (© 2024 Wiley-VCH GmbH.)

The skin microenvironment created by keratinocytes (KC) influences the stress responses of melanocytes (MC) to UVB insults. This study employed RNA sequencing analysis as well as in vitro and in vivo models to elucidate the underlying mechanisms. Our RNA-Seq analysis revealed a statistically significant upregulation of GCSF and CCL20 genes in UVB-irradiated KC, correlating with the protective effects of KC on MC responses to UVB exposure. Recombinant GCSF and CCL20 exhibited the most pronounced modulation of UVB-induced MC responses. These effects included the attenuation of apoptosis and reduction of ROS formation, along with the upregulation of tyrosinase and tyrosinase-related protein-1, which are involved in the melanogenic pathway. ELISA was also used to confirm that UVB could induce the secretion of GCSF and CCL20 from KC. A similar correlation between GCSF and CCL20 expression in KC and tyrosinase levels in MC was observed in UVB-irradiated mouse skin. Our study provides novel insights into the protective role of GCSF and CCL20 in the paracrine effects of KC on UVB-induced MC damage through the modulation of stress response pathways, the MITF-tyrosinase axis, and the regulation of p53. These findings have implications for the development of pharmacological strategies targeting KC-derived paracrine factors for the prevention of skin photodamage.

In response to pro-inflammatory cytokines such as interleukin (IL)-1β, dental pulp fibroblasts produce various inflammatory mediators, including IL-6, IL-8, CC chemokine ligand 20 (CCL20), and CXC chemokine ligand 10 (CXCL10), leading to the progression of pulpitis. IL-17/IL-17A (IL-17A) is a pro-inflammatory cytokine secreted by T helper (Th) 17 cells following their recruitment to inflamed sites; however, the roles of IL-17A during pulpitis remain unclear. The purpose of this study was to investigate the effect of IL-17A on IL-6, IL-8, CCL20 and CXCL10 production by human dental pulp fibroblasts (HDPFs) in vitro. IL-17A at a concentration of 100 ng/ml induced the production of 10 times more IL-8 and 4 times more CXCL10, but not IL-6 and CCL20, compared to controls. Co-stimulation of HDPFs with IL-17A and IL-1β synergistically enhanced the production of IL-6, CCL20, IL-8 and CXCL10. IL-1β increased expression of IL-17 receptor/IL-17RA (IL-17R) on HDPFs. Moreover, the cell signal pathways of p38 mitogen-activated protein kinase (MAPK) and nuclear factor-κB (NF-κB) were more potently activated by simultaneous stimulation with IL-17A and IL-1β. These findings suggest that IL-17A participates in the progression of dental pulp inflammation through the enhanced production of inflammatory mediators in HDPFs., (© 2024 Scandinavian Division of the International Association for Dental Research. Published by John Wiley & Sons Ltd.)

Metabolic changes play a crucial role in determining the status and function of macrophages, but how lipid reprogramming in macrophages contributes to tumor progression is not yet fully understood. Here, we investigated the phenotype, contribution, and regulatory mechanisms of lipid droplet (LD)-laden macrophages (LLMs) in hepatocellular carcinoma (HCC). Enriched LLMs were found in tumor tissues and were associated with disease progression in HCC patients. The LLMs displayed immunosuppressive phenotypes (with extensive expression of TREM2, PD-L1, CD206, and CD163) and attenuated the antitumor activities of CD8 + T cells. Mechanistically, tumor-induced reshuffling of cellular lipids and TNFα-mediated uptake of tumoral fatty acids contribute to the generation of triglycerides and LDs in macrophages. LDs prolong LLM survival and promote CCL20 secretion, which further recruits CCR6 + Tregs to HCC tissue. Inhibiting LLM formation by targeting DGAT1 and DGAT2, which catalyze the synthesis of triglycerides, significantly reduced Treg recruitment, and delayed tumor growth in a mouse hepatic tumor model. Our results reveal the suppressive phenotypes and mechanisms of LLM enrichment in HCC and suggest the therapeutic potential of targeting LLMs for HCC patients., (© 2024. The Author(s), under exclusive licence to CSI and USTC.)

Background: Chemotactic cytokines play a crucial role in the development of acute myeloid leukemia (AML). Thus, investigating the mechanisms of chemotactic cytokine-related genes (CCRGs) in AML is of paramount importance., Methods: Using the TCGA-AML, GSE114868, and GSE12417 datasets, differential expression analysis identified differentially expressed CCRGs (DE-CCRGs). These genes were screened by overlapping differentially expressed genes (DEGs) between AML and control groups with CCRGs. Subsequently, functional enrichment analysis and the construction of a protein-protein interaction (PPI) network were conducted to explore the functions of the DE-CCRGs. Univariate Cox regression, least absolute shrinkage and selection operator (LASSO), and multivariate Cox regression analyses identified relevant prognostic genes and developed a prognostic model. Survival analysis of the prognostic gene was performed, followed by functional similarity analysis, immune analysis, enrichment analysis, and drug prediction analysis., Results: Differential expression analysis revealed 6,743 DEGs, of which 29 DE-CCRGs were selected for this study. Functional enrichment analysis indicated that DE-CCRGs were primarily involved in chemotactic cytokine-related functions and pathways. Six prognostic genes (CXCR3, CXCR2, CXCR6, CCL20, CCL4, and CCR2) were identified and incorporated into the risk model. The model's performance was validated using the GSE12417 dataset. Survival analysis showed significant differences in AML overall survival (OS) between prognostic gene high and low expression groups, indicating that prognostic gene might be significantly associated with patient survival. Additionally, nine different immune cells were identified between the two risk groups. Correlation analysis revealed that CCR2 had the most significant positive correlation with monocytes and the most significant negative correlation with resting mast cells. The tumor immune dysfunction and exclusion score was lower in the high-risk group., Conclusion: CXCR3, CXCR2, CXCR6, CCL20, CCL4, and CCR2 were identified as prognostic genes correlated to AML and the tumor immune microenvironment. These findings offerred novel insights into the prevention and treatment of AML., Competing Interests: The authors declare there are no competing interests., (©2024 Hou et al.)

Introduction: It is crucial to investigate the distinct proteins that contribute to the advancement of lung cancer., Material and Methods: We analyzed the expression levels of 92 immuno-oncology-related proteins in 96 pairs of lung adenocarcinoma tissue samples using Olink proteomics. The differentially expressed proteins (DEPs) were successively screened in tumor and paraneoplastic groups, early and intermediate-late groups by a nonparametric rank sum test, and the distribution and expression levels of DEPs were determined by volcano and heat maps, etc., and the area under the curve was calculated., Results: A total of 24 DEPs were identified in comparisons between tumor and paracancerous tissues. Among them, interleukin-8 (IL8) and chemokine (C-C motif) ligand 20 (CCL20) as potential markers for distinguishing tumor tissues. Through further screening, it was found that interleukin-6 (IL6) and vascular endothelial growth factor A (VEGFA) may be able to lead to tumor progression through the JaK-STAT signaling pathway, Toll-like receptor signaling pathway and PI3K/AKT signaling pathway. Interestingly, our study revealed a down-regulation of IL6 and VEGFA in tumor tissues compared to paracancerous tissues., Conclusions: IL8 + CCL20 (AUC: 0.7056) have the potential to differentiate tumor tissue from paracancerous tissue; IL6 + VEGFA (AUC: 0.7531) are important protein markers potentially responsible for tumor progression.

Obesity is endemic to many developed countries. Overweight or obesity is associated with an increased risk of developing cancer. Dysfunctional adipose tissue alters cancer cell proliferation and migration; however, whether and how neoplastic epithelial cells communicate with adipose tissue and the underlying mechanism are less clear. BTG3 is a member of the anti-proliferative BTG/Tob family and functions as a tumor suppressor. Here, we demonstrated that BTG3 levels are downregulated in basal cell carcinoma and squamous cell carcinoma compared to normal skin tissue, and Btg3 knockout in mice augmented the development of papilloma in a mouse model of DMBA/TPA-induced skin carcinogenesis. Mechanistically, BTG3-knockout keratinocytes promoted adipocyte differentiation mainly through the release of IL1α, IL10, and CCL4, as a result of elevated NF-κB activity. These adipocytes produced CCL20 and FGF7 in a feedback loop to promote keratinocyte migration. Thus, our findings showcased the role of BTG3 in guarding the interplay between keratinocytes and adjacent adipocytes, and identified the underlying neoplastic molecular mediators that may serve as possible targets in the treatment of skin cancer., (© 2024. The Author(s).)

Background and Purpose: The interleukin (IL)-36 pathway is a critical player in the pathogenesis of pustular psoriasis. However, therapies targeting this pathway are limited or unaffordable (e.g. the anti-IL-36 receptor antibody). AMP-activated protein kinase (AMPK), a regulator of cellular energy and metabolism, is known to participate in inflammatory diseases. However, its role in IL-36-induced skin inflammation remains unclear. Therefore, we sought to investigate the role of AMPK signals in regulating IL-36-induced responses in the skin., Experimental Approach: IL-36-stimulated primary normal human epidermal keratinocytes (NHEKs) and IL-36-injected (intradermally) BALB/c mice served as the cell and animal models, respectively. Additionally, 5-aminoimidazole-4-carboxamide riboside (AICAR) and A769662 served as AMPK activators., Key Results: AICAR and A769662 significantly suppressed the IL-36-induced IL-8 (CXCL8) and CCL20 production from NHEKs. IL-36-induced IκBζ protein expression was prominently reduced and IKK/IκBα phosphorylation was attenuated by AICAR and A769662. Conversely, AMPKα knockdown increased IκBζ protein expression and IKK/IκBα phosphorylation in IL-36-treated NHEKs. Furthermore, AICAR and A769662 enhanced IL-36-induced-IκBζ protein degradation via the proteasome-dependent but not the lysosome-dependent pathway. Pretreatment of NHEKs with IL-36 slightly suppressed the AICAR- and A769662-triggered phosphorylation of AMPK and acetyl-CoA carboxylase. In the mouse model, topical application of AICAR significantly reduced ear swelling, redness, epidermal thickening, neutrophil infiltration and inflammatory and antimicrobial peptide gene expression., Conclusion and Implications: AMPK activation suppresses IL-36-induced IL-8 and CCL20 release by regulating IκBζ expression in keratinocytes and reduces IL-36-induced skin inflammation in mice, suggesting that AMPK activation is a potential strategy for treating patients with IL-36-mediated inflammatory skin disorders., (© 2024 British Pharmacological Society.)

Programmed cell death ligand 2 (PD-L2), a ligand for the receptor programmed cell death 1 (PD-1), has an identity of 34% with its twin ligand PD-L1 and exhibits higher binding affinity with PD-1 than PD-L1. However, the role of PD-L2 in non-small cell lung cancer (NSCLC) progression, especially tobacco-induced cancer progression, has not been fully understood. Here, we found that PD-L2 promoted tumor growth in murine models with recruitment of regulatory T cells (Tregs). In patients with NSCLC, PD-L2 expression level in tumor samples was higher than in counterpart normal controls and was positively associated with patients' response to anti-PD-1 treatment. Mechanismly, PD-L2 bound its receptor Repulsive guidance molecule B (RGMB) on cancer cells and activated extracellular signal-regulated kinase (Erk) and nuclear factor κB (NFκB), leading to increased production of chemokine CCL20, which recruited Tregs and contributed to NSCLC progression. Consistently, knockdown of RGMB or NFκB p65 inhibited PD-L2-induced CCL20 production, and silencing of PD-L2 repressed Treg recruitment by NSCLC cells. Furthermore, cigarette smoke and carcinogen benzo(a)pyrene (BaP) upregulated PD-L2 in lung epithelial cells via aryl hydrocarbon receptor (AhR)-mediated transcription activation, whose deficiency markedly suppressed BaP-induced PD-L2 upregulation. These results suggest that PD-L2 mediates tobacco-induced recruitment of Tregs via the RGMB/NFκB/CCL20 cascade, and targeting this pathway might have therapeutic potentials in NSCLC., (© 2024. The Author(s).)

The migration of γδ T lymphocytes toward skin lesions and their concomitant pathogenic IL-17A production play a crucial role in the pathogenesis of psoriasis. However, the regulatory mechanisms of IL-17A production by γδ T cells and their migration remain to be fully explored. Intracellular GRP78 is a molecular chaperone that regulates endoplasmic reticulum stress, whereas secretory GRP78, as a member of the resolution-associated molecular patterns, exerts immunoregulatory effects. In this study, we reported that both the intracellular GRP78 in skin lesions and secretory GRP78 in the serum were significantly decreased in patients with psoriasis. A GRP78 knockdown exacerbated imiquimod-induced skin inflammation, whereas the application of recombinant GRP78 protein or BIP inducer X (a GRP78 inducer) attenuated the dermatitis. Mechanistically, the GRP78 knockdown in keratinocytes enhanced the production of chemokines, specifically CCL20, which regulates γδ T-cell migration. Moreover, recombinant GRP78 was found to directly bind to γδ T cells to suppress its migration ability and proinflammatory capacities by downregulating the CCR6 and IL-17A expression. Collectively, our results uncovered a pivotal role of GRP78 in the pathogenesis of psoriasis, which was mainly exerted by regulating the interaction between keratinocytes and γδ T cells, and might provide a promising target for psoriasis therapy., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Ischemic stroke (IS) is of increasing concern given the aging population and prevalence of unhealthy lifestyles, with older females exhibiting higher susceptibility. This study aimed to identify practical diagnostic markers, develop a diagnostic model for immunogenic cell death (ICD)-associated IS, and investigate alterations in the immune environment caused by hub genes. Differentially expressed genes associated with ICD in IS were identified based on weighted gene co-expression network analysis and the identification of significant modules. Subsequently, machine learning algorithms were employed to screened hub genes, which were further assessed using Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, and Gene Set Enrichment Analysis. A nomogram mode lwas then constructed for IS diagnosis, and its diagnostic value was assessed using a receiver operating characteristic curve. Finally, alterations in immune cell infiltration were assessed within patients with IS, and the pan-cancer expression patterns of hub genes were evaluated. Three hub genes associated with ICD (PDK4, CCL20, and FBL) were identified. The corresponding nomogram model for IS diagnosis could effectively identify older female patients with IS (area under the curve (AUC) = 0.9555). Overall, the three hub genes exhibit good diagnostic value (AUC > 0.8). CCL20 and FBL are significantly associated with the extent of immune cells infiltration. Moreover, a strong link exists between hub gene expression and pan-cancer prognosis. Cumulatively, these results indicate that ICD-related hub genes critically influence IS progression in older females, presenting novel diagnostic and therapeutic targets for personalized treatment., (© 2024. The Author(s).)

TNF receptor superfamily member 11a (TNFRSF11a, RANK) and its ligand TNF superfamily member 11 (TNFRSF11, RANKL) are overexpressed in many malignancies. However, the clinical importance of RANKL/RANK in colorectal cancer (CRC) is mainly unknown. We examined CRC samples and found that RANKL/RANK was elevated in CRC tissues compared with nearby normal tissues. A higher RANKL/RANK expression was associated with a worse survival rate. Furthermore, RANKL was mostly produced by regulatory T cells (Tregs), which were able to promote CRC advancement. Overexpression of RANK or addition of RANKL significantly increased the stemness and migration of CRC cells. Furthermore, RANKL/RANK signaling stimulated C-C motif chemokine ligand 20 (CCL20) production by CRC cells, leading to Treg recruitment and boosting tumor stemness and malignant progression. This recruitment process was accomplished by CCL20-CCR6 interaction, demonstrating a connection between CRC cells and immune cells. These findings suggest an important role of RANKL/RANK in CRC progression, offering a potential target for CRC prevention and therapy., (© 2024. The Author(s).)

Background: Hepatocellular carcinoma (HCC), a globally common cancer, often presents late and shows high resistance to chemotherapy, resulting in suboptimal treatment efficacy. Components from traditional Chinese medicines have been recognized for their anti-cancer properties., Objective: Exploring the mechanism of Schisandra chinensis lignans and acteoside in suppressing Epithelial-Mesenchymal Transition (EMT) in hepatoma cells through the Extracellular signal-Regulated Kinases (ERK)1/2 pathway and identifying biomarkers, molecular subtypes, and targets via multi-omics for precision oncology., Methods: Proliferation was assessed using cell counting kit-8 (CCK-8) assays, with scratch and transwell assays for evaluating invasion and migration. Flow cytometry quantified apoptosis rates. Expression levels of CCL20, p-ERK1/2, c-Myc, Vimentin, and E-cadherin/N-cadherin were analyzed by real-time PCR and Western blot. Tumor volume was calculated with a specific formula, and growth., Results: The Schisandra chinensis lignans and acteoside combination decreased CCL20 expression, inhibited hepatoma proliferation and migration, and enhanced apoptosis in a dose- and time-dependent manner. Molecular analysis revealed increased E-cadherin and decreased N-cadherin, p-ERK1/2, c-Myc, and Vimentin expression, indicating ERK1/2 pathway modulation. In vivo, treated nude mice showed significantly reduced tumor growth and volume., Conclusion: Schisandra chinensis lignans and acteoside potentially counteract CCL20-induced EMT, invasion, and migration in hepatocellular carcinoma cells via the ERK1/2 pathway, enhancing apoptosis. Multi-omics analysis further aids in pinpointing novel biomarkers for precision cancer therapy., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Psoriasis is an immune-mediated chronic inflammatory skin disease. Current research suggests that the long-term persistence and recurrence of psoriasis are closely related to the feedback loop formed between keratinocytes and immune cells, especially in Th 17 or DC cells expressing CCR6. CCL20 is the ligand of CCR6. Therefore, drugs that block the expression of CCL20 or CCR6 may have a certain therapeutic effect on psoriasis. Glycyrrhetinic acid (GA) is the main active ingredient of the plant drug licorice and is often used to treat autoimmune diseases, including psoriasis. However, its mechanism of action is still unclear., Methods: Psoriasis like skin lesion model was established by continuously applying imiquimod on the back skin of normal mice and CCR6-/- mice for 7 days. The therapeutic and preventive effects of glycyrrhetinic acid (GA) on the model were observed and compared. The severity of skin injury is estimated through clinical PASI scores and histopathological examination. qRT-PCR and multiple cytoline assay were explored to detect the expression levels of cytokines in animal dorsal skin lesions and keratinocyte line HaCaT cells, respectively. The dermis and epidermis of the mouse back were separated for the detection of CCL20 expression. Transcription factor assay was applied to screen, and luciferase activity assay to validate transcription factors regulated by GA. Technology of surface plasmon laser resonance with LC-MS (SPR-MS), molecular docking, and enzyme activity assay were used to identified the target proteins for GA. Finally, we synthesized different derivatives of 18beta-GA and compared their effects, as well as glycyrrhetinic acid (GL), on the skin lesion of imiquimod-induced mice to evaluate the active groups of 18beta-GA., Results: 18β-glycyrrhetinic acid (GA) improved IMQ-induced psoriatic lesions, and could specifically reduce the chemokine CCL20 level of the epidermis in lesion area, especially in therapeutic administration manner. The process was mainly regulated by transcription factor ATF2 in the keratinocytes. In addition, GUSB was identified as the primary target of 18βGA. Our findings indicated that the subject on molecular target research of glycyrrhizin should be glycyrrhetinic acid (GA) instead of glycyrrhizic acid (GL), because GL showed little activity in vitro or in vivo. Apart from that, α, β, -unsaturated carbonyl in C11/12 positions was crucial or unchangeable to its activity of 18βGA, while proper modification of C3 or C30 position of 18βGA may vastly increase its activity., Conclusion: Our research indicates that 18βGA exerted its anti-psoriasis effect mainly by suppressing ATF2 and downstream molecule CCL20 predominately through α, β, -unsaturated carbonyl at C11/12 position binding to GUSB in the keratinocytes, and then broke the feedback loop between keratinocytes and CCR6-expressing immune cells. GA has more advantages than GL in the external treatment of psoriasis. A highlight of this study is to investigate the influence of special active groups on the pharmacological action of a natural product, inspired by the molecular docking result., Competing Interests: Declaration of competing interest The authors declare that this research was conducted in the absence of any commercial or financial relationships that can be construed as a potential conflict of interest., (Copyright © 2024 Elsevier GmbH. All rights reserved.)

TH1L (also known as NELF-C/D) is a member of the Negative Elongation Factor (NELF) complex, which is a metazoan-specific factor that regulates RNA Polymerase II (RNAPII) pausing and transcription elongation. However, the function and molecular mechanisms of TH1L in cancer progression are still largely unknown. In this study, we found that TH1L was highly expressed in colorectal cancer (CRC) tissues and the faeces of CRC patients. Overexpression of TH1L significantly enhanced the proliferation and migration of CRC cells, while its knockdown markedly suppressed these processes. In mechanism, RNA sequencing revealed that CCL20 was upregulated in TH1L-overexpressed CRC cells, leading to activation of the NF-κB signalling pathway. Rescue assays showed that knockdown of CCL20 could impair the tumour-promoting effects of THIL in CRC cells. Taken together, these results suggest that TH1L may play a vital role via the CCL20/NF-κB signalling pathway in CRC proliferation and migration and may serve as a potential target for diagnosis and therapy of CRC., (© 2024 The Author(s). Journal of Cellular and Molecular Medicine published by Foundation for Cellular and Molecular Medicine and John Wiley & Sons Ltd.)

Chronic prostatitis and chronic pelvic pain syndrome (CP/CPPS), a prevalent urological ailment, exerts a profound influence upon the well-being of the males. Autoimmunity driven by Th17 cells has been postulated as a potential factor in CP/CPPS pathogenesis. Nonetheless, elucidating the precise mechanisms governing Th17 cell recruitment to the prostate, triggering inflammation, remained an urgent inquiry. This study illuminated that CCL20 played a pivotal role in attracting Th17 cells to the prostate, thereby contributing to prostatitis development. Furthermore, it identified prostate stromal cells and immune cells as likely sources of CCL20. Additionally, this research unveiled that IL-17A, released by Th17 cells, could stimulate macrophages to produce CCL20 through the NF-κB/MAPK/PI3K pathway. The interplay between IL-17A and CCL20 establishes a positive feedback loop, which might serve as a critical mechanism underpinning the development of chronic prostatitis, thus adding complexity to its treatment challenges., (© 2024 The Author(s). Journal of Cellular and Molecular Medicine published by Foundation for Cellular and Molecular Medicine and John Wiley & Sons Ltd.)

Background: Activation of VDR pathway was a promising anti-tumor therapy strategy. However, numerous clinical studies have demonstrated the effect of activating VDR is limited, which indicates that VDR plays a complex role in vivos., Methods: We analyzed the TCGA database to examine the association between VDR expression and immune cell infiltration in pancreatic adenocarcinoma (PAAD). Western blot, ELISA, ChIP, and dual-luciferase reporter assays were performed to determine the mechanism of VDR regulating CCL20. Migration assay and immunofluorescence were used to investigate the role of CCL20 in M2 macrophage polarization and recruitment. We employed multiplexed immunohistochemical staining and mouse models to validate the correlation of VDR on macrophages infiltration in PAAD. Flow cytometry analysis of M2/M1 ratio in subcutaneous graft tumors., Results: VDR is extensively expressed in PAAD, and patients with elevated VDR levels exhibited a significantly reduced overall survival. VDR expression in PAAD tissues was associated with increased M2 macrophages infiltration. PAAD cells overexpressing VDR promote macrophages polarization towards M2 phenotype and recruitment in vitro and vivo. Mechanistically, VDR binds to the CCL20 promoter and up-regulates its transcription. The effects of polarization and recruitment on macrophages can be rescued by blocking CCL20. Finally, the relationship between VDR and M2 macrophages infiltration was evaluated using clinical cohort and subcutaneous graft tumors. A positive correlation was demonstrated between VDR/CCL20/CD163 in PAAD tissues and mouse models., Conclusion: High expression of VDR in PAAD promotes M2 macrophage polarization and recruitment through the secretion of CCL20, which activates tumor progression. This finding suggests that the combination of anti-macrophage therapy may improve the efficacy of VDR activation therapy in PAAD., (© 2024. The Author(s).)

Abstract: Damage to the abdominal aortic wall and the local inflammatory response are key factors resulting in abdominal aortic aneurysm (AAA) formation. During this process, macrophage polarization plays a key role. However, in AAA, the regulatory mechanism of macrophages is still unclear, and further research is needed. In this study, we found that the transcription factor TCF3 was expressed at low levels in AAA. We overexpressed TCF3 and found that TCF3 could inhibit MMP and inflammatory factor expression and promote M2 macrophage polarization, thereby inhibiting the progression of AAA. Knocking down TCF3 could promote M1 polarization and MMP and inflammatory factor expression. In addition, we found that TCF3 increased miR-143-5p expression through transcriptional activation of miR-143-5p , which further inhibited expression of the downstream chemokine CCL20 and promoted M2 macrophage polarization. Our research indicates that TCF3-mediated macrophage polarization plays a key regulatory role in AAA, complementing the role and mechanism of macrophages in the occurrence and development of AAA and providing a scientific basis for AAA treatment., Competing Interests: The authors report no conflicts of interest., (Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc.)

Intraventricular hemorrhage (IVH) commonly occurs as an extension of intracerebral hemorrhage (ICH) into the brain ventricular system, leading to worse outcomes without effective management. Using a mouse model of IVH, we found that impaired neurogenesis is evident in the subventricular zone (SVZ), along with persistent microglia activation, leukocyte infiltration and cell death. Pharmacological depletion of microglia using PLX3397, an inhibitor of colony stimulating factor 1 receptor (CSF1R), promotes neurogenesis, and alleviated delayed functional impairments in IVH mice. Meanwhile, an elevated level of microglia-derived CC chemokine ligand 20 (CCL20) is observed in the SVZ following IVH, which can induce the upregulation of pro-inflammatory factors in microglia and impair the proliferation and survival of neural stem cells (NSCs) in vitro. Blocking CCL20 in microglia leads to downregulation of protein kinase B (Akt)/mammalian target of rapamycin (mTOR)/the nuclear factor-κB (NF-κB) signaling pathway, which may contribute to CCL20-dependent pro-inflammatory responses and neural injury. These findings demonstrate a detrimental role of microglia in the neurogenesis and neurorepair after IVH in which CCL20 likely plays a role., Competing Interests: Declaration of Competing Interest All authors declare no competing interests., (Copyright © 2023. Published by Elsevier Inc.)

Objectives: Th17 cells are known to play a significant role in AS. C-C motif chemokine ligand 20 (CCL20) binds to C-C chemokine receptor 6 (CCR6) on Th17 cells, promoting their migration to inflammation sites. The aim of this research is to examine the effectiveness of CCL20 inhibition in treating inflammation in AS., Methods: Mononuclear cells from peripheral blood (PBMC) and SF (SFMC) were collected from healthy individuals and AS. Flow cytometry was used to analyse cells producing inflammatory cytokines. CCL20 levels were determined using ELISA. The impact of CCL20 on Th17 cell migration was verified using a Trans-well migration assay. The in vivo efficacy of CCL20 inhibition was evaluated using an SKG mouse model., Results: The presence of Th17 cells and CCL20 expressing cells was higher in SFMCs from AS patients compared with their PBMCs. The CCL20 level in AS SF was significantly higher than in OA patients. The percentage of Th17 cells in PBMCs from AS patients increased when exposed to CCL20, whereas the percentage of Th17 cells in SFMCs from AS patients decreased when treated with CCL20 inhibitor. The migration of Th17 cells was found to be influenced by CCL20, and this effect was counteracted by the CCL20 inhibitor. In the SKG mouse model, the use of CCL20 inhibitor significantly reduced joint inflammation., Conclusion: This research validates the critical role of CCL20 in AS and suggests that targeting CCL20 inhibition could serve as a novel therapeutic approach for AS treatment., (© The Author(s) 2023. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Background: Peroxisome proliferator-activated receptor delta (PPARδ) promotes inflammation and carcinogenesis in many organs, but the underlying mechanisms remains elusive. In stomachs, PPARδ significantly increases chemokine Ccl20 expression in gastric epithelial cells while inducing gastric adenocarcinoma (GAC). CCR6 is the sole receptor of CCL20. Here, we examine the role of PPARδ-mediated Ccl20/Ccr6 signaling in GAC carcinogenesis and investigate the underlying mechanisms., Methods: The effects of PPARδ inhibition by its specific antagonist GSK3787 on GAC were examined in the mice with villin-promoter-driven PPARδ overexpression (Ppard TG ). RNAscope Duplex Assays were used to measure Ccl20 and Ccr6 levels in stomachs and spleens. Subsets of stomach-infiltrating immune cells were measured via flow cytometry or immunostaining in Ppard TG mice fed GSK3787 or control diet. A panel of 13 optimized proinflammatory chemokines in mouse sera were quantified by an enzyme-linked immunosorbent assay., Results: GSK3787 significantly suppressed GAC carcinogenesis in Ppard TG mice. PPARδ increased Ccl20 level to chemoattract Ccr6 + immunosuppressive cells, including tumor-associated macrophages, myeloid-derived suppressor cells and T regulatory cells, but decreased CD8 + T cells in gastric tissues. GSK3787 suppressed PPARδ-induced gastric immunosuppression by inhibiting Ccl20/Ccr6 axis. Furthermore, Ccl20 protein levels increased in sera of Ppard TG mice starting at the age preceding gastric tumor development and further increased with GAC progression as the mice aged. GSK3787 decreased the PPARδ-upregulated Ccl20 levels in sera of the mice., Conclusions: PPARδ dysregulation of Ccl20/Ccr6 axis promotes GAC carcinogenesis by remodeling gastric tumor microenvironment. CCL20 might be a potential biomarker for the early detection and progression of GAC., (© 2023. The Author(s).)

CC chemokine receptor 6 (CCR6) is a member of the G-protein-coupled receptor family that is highly expressed in B lymphocytes, effector and memory T cells, regulatory T cells, and immature dendritic cells. CCR6 has been revealed to have important functions in many pathological conditions, such as cancer, intestinal bowel disease, psoriasis, and autoimmune diseases. The only CCR6 chemokine ligand, CC motif chemokine ligand 20 (CCL20), is also involved in pathogenesis by interacting with CCR6. The CCL20/CCR6 axis is drawing attention as an attractive therapeutic target for various diseases. In this study, we developed novel monoclonal antibodies (mAbs) against human CCR6 (hCCR6) using the peptide immunization method, which are applicable to flow cytometry and immunohistochemistry. The established anti-hCCR6 mAb, clone C 6 Mab-19 (mouse IgG 1 , kappa), reacted with hCCR6-overexpressed Chinese hamster ovary-K1 (CHO/hCCR6), human liver carcinoma (HepG2), and human differentiated hepatoma (HuH-7) cells in flow cytometry. The dissociation constant ( K D ) of C 6 Mab-19 was determined as 3.0 × 10 -10 M for CHO/hCCR6, 6.9 × 10 -10 M for HepG2, and 1.8 × 10 -10 M for HuH-7. Thus, C 6 Mab-19 could bind to exogenously and endogenously expressed hCCR6 with extremely high affinity. Furthermore, C 6 Mab-19 could stain formalin-fixed paraffin-embedded lymph node tissues from a patient with non-Hodgkin lymphoma by immunohistochemistry. Therefore, C 6 Mab-19 is suitable for detecting hCCR6-expressing cells and tissues and could be useful for pathological analysis and diagnosis.

Previous studies have identified a unique Treg population, which expresses the Th17 characteristic transcription factor RORγt. These RORγt + Tregs possess enhanced immunosuppressive capacity, which endows them with great therapeutic potential. However, as a caveat, they are also capable of secreting pro-inflammatory IL-17A. Since the sum function of RORγt + Tregs in glomerulonephritis (GN) remains unknown, we studied the effects of their absence. Purified CD4 + T cell populations, containing or lacking RORγt + Tregs, were transferred into immunocompromised RAG1 knockout mice and the nephrotoxic nephritis model of GN was induced. Absence of RORγt + Tregs significantly aggravated kidney injury, demonstrating overall kidney-protective properties. Analyses of immune responses showed that RORγt + Tregs were broadly immunosuppressive with no preference for a particular type of T cell response. Further characterization revealed a distinct functional and transcriptional profile, including enhanced production of IL-10. Expression of the chemokine receptor CCR6 marked a particularly potent subset, whose absence significantly worsened GN. As an underlying mechanism, we found that chemokine CCL20 acting through receptor CCR6 signaling mediated expansion and activation of RORγt + Tregs. Finally, we also detected an increase of CCR6 + Tregs in kidney biopsies, as well as enhanced secretion of chemokine CCL20 in 21 patients with anti-neutrophil cytoplasmic antibody associated GN compared to that of 31 healthy living donors, indicating clinical relevance. Thus, our data characterize RORγt + Tregs as anti-inflammatory mediators of GN and identify them as promising target for Treg directed therapies., (Copyright © 2023 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.)

Background:  Radioresistance of HNSCCs remains a major challenge for effective tumor control. Combined radiotherapy (RT) and immunotherapy (IT) treatment improved survival for a subset of patients with inflamed tumors or tumors susceptible to RT-induced inflammation. To overcome radioresistance and improve treatment outcomes, an understanding of factors that suppress anti-tumor immunity is necessary. In this regard, regulatory T cells (Tregs) are critical mediators of immune suppression in HNSCCs. In this study, we investigated how radiation modulates Treg infiltration in tumors through the chemokine CCL20. We hypothesized that radiation induces CCL20 secretion resulting in Treg infiltration and suppression of anti-tumor immunity., Methods:  Human and mouse HNSCC cell lines with different immune phenotypes were irradiated at doses of 2 or 10 Gy. Conditioned media, RNA and protein were collected for assessment of CCL20. qPCR was used to determine CCL20 gene expression. In vivo, MOC2 cells were implanted into the buccal cavity of mice and the effect of neutralizing CCL20 antibody was determined alone and in combination with RT. Blood samples were collected before and after RT for analysis of CCL20. Tumor samples were analyzed by flow cytometry to determine immune infiltrates, including CD8 T cells and Tregs. Mass-spectrometry was performed to analyze proteomic changes in the tumor microenvironment after anti-CCL20 treatment., Results:  Cal27 and MOC2 HNSCCs had a gene signature associated with Treg infiltration, whereas SCC9 and MOC1 tumors displayed a gene signature associated with an inflamed TME. In vitro, tumor irradiation at 10 Gy significantly induced CCL20 in Cal27 and MOC2 cells relative to control. The increase in CCL20 was associated with increased Treg migration. Neutralization of CCL20 reversed radiation-induced migration of Treg cells in vitro and decreased intratumoral Tregs in vivo. Furthermore, inhibition of CCL20 resulted in a significant decrease in tumor growth compared to control in MOC2 tumors. This effect was further enhanced after combination with RT compared to either treatment alone., Conclusion:  Our results suggest that radiation promotes CCL20 secretion by tumor cells which is responsible for the attraction of Tregs. Inhibition of the CCR6-CCL20 axis prevents infiltration of Tregs in tumors and suppresses tumor growth resulting in improved response to radiation., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Psoriasis is an autoimmune chronic inflammatory skin disease with an unclear pathogenesis that is difficult to cure, causing serious physical and mental burdens for patients. Previous research showed that a mutually reinforcing vicious cycle caused by keratinocytes (KC) and a variety of immune cells plays an important role in psoriatic inflammation. d-Mannose, a widely distributed metabolite in the body, has been found to treat several metabolic diseases, but its impact on psoriasis remains unknown. Our study aims to investigate the effects of d-mannose on psoriasis and its specific mechanism. Here, we found that d-mannose alleviates psoriasis in mice both as oral and topical agents. Specifically, d-mannose down-regulated the expression of hypoxia-inducible factor 1A(HIF-1α) and inhibited the expression of chemokine CCL20 in keratinocytes, thereby inhibiting the local infiltration of Th17 cells and breaking the cycle of keratinocytes-Th17 cells. Overall, our study indicates that d-mannose alleviates cutaneous inflammation in psoriasis by inhibiting the HIF-1α/CCL20/Th17 cells axis, and d-mannose has the potential to be used as an oral and topical agent in the treatment of psoriasis., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

The suppression of androgen receptor (AR) expression exacerbates the migration potential of prostate cancer. This study identified a previously unrecognized regulation of the AR-controlled pathway that promotes migration potential in prostate cancer cells. Prostate cancer cells that pass through a transwell membrane (mig cells) have a higher migration potential with a decreased AR expression than parental cells. In this study, we aimed to elucidate the mechanism of migration enhancement associated with the suppression of AR signaling. Expression of C-C motif ligand 20 (CCL20) is upregulated in mig cells, unlike in the parental cells. Knockdown of AR with small interfering RNA (siAR) in LNCaP and C4-2B cells increased CCL20 secretion and enhanced the migration of cancer cells. Mig cells, CCL20-treated cells, and siAR cells promoted cell migration with an enhancement of AKT phosphorylation and Snail expression, while the addition of a C-C chemokine receptor 6 (CCR6, the specific receptor of CCL20) inhibitor, anti-CCL20 antibody, and AKT inhibitor suppressed the activation of AKT and Snail. With 59 samples of prostate cancer tissue, CCL20 secretion was profuse in metastatic cases despite low AR expression levels. Snail expression was associated with the expression of CCL20 and CCR6. A xenograft study showed that the anti-CCL20 antibody significantly inhibited Snail expression, thereby suggesting a new therapeutic approach for castration-resistant prostate cancer with the inhibition of the axis between CCL20 and CCR6., (© 2022 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.)

Chemokines are a group of small proteins that induce chemoattraction and inflammation and contribute to the differentiation and homeostasis of various cell types. Here we explored the role of chemokines, extracellular matrix production, and myofibroblast differentiation in self-assembled skin equivalents (SASE), a three-dimensional (3D) skin-equivalent tissue model. We found that the expression of three chemokines, C-C motif chemokine ligand (CCL) 20, C-X-C motif chemokine ligand (CXCL) 5, and CXCL8, increased with differentiation to myofibroblasts. Addition of recombinant CCL20 to human skin fibroblast induced collagen Type I alpha 2 gene expression, but did not affect the expression of alpha smooth muscle actin expression. Conversely, siRNA gene knockdown of CCL20 effectively inhibited the expression of collagen Type I gene and protein. Furthermore, when the CCL20 gene in fibroblasts was knocked down in SASE, collagen Type I synthesis and stromal thickness were decreased. Taken together, these results have indicated the utility of SASE in understanding how cytokines such as CCL20 positively regulate extracellular matrix proteins such as collagen Type I production during myofibroblast differentiation in 3D tissues that mimic human skin., (© 2022 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

The pro-inflammatory cytokine, chemokine (C-C motif) ligand 20 (CCL20), is emerging as a therapeutic target for immune-based therapies. Cooperative regulation of CCL20 by glucocorticoids and progestins used in endocrine therapy and pro-inflammatory mediators could modulate immune function and affect disease outcomes. We show that glucocorticoids as well as medroxyprogesterone acetate (MPA), the progestin widely used in injectable contraception in sub-Saharan Africa, cooperate with pro-inflammatory mediators to upregulate CCL20 protein and/or mRNA in human peripheral blood mononuclear cells (PBMCs) and human cervical cell lines. Changes in CCL20 mRNA levels were shown to be synergistic, as assessed by Chou analysis, cell- and gene-specific and to involve transcriptional regulation, with a requirement for a nuclear factor kappa B (NF-κB) site and glucocorticoid receptor (GR) involvement. The novel results suggest a mechanism whereby MPA, like glucocorticoids, may impact inflammation both systemically and in the genital tract in patients using MPA and/or glucocorticoid therapy., Competing Interests: Declaration of competing interest The authors declare no competing interests., (Copyright © 2023 Elsevier B.V. All rights reserved.)

The CCL20/CCR6 axis is implicated in the migration of CCR6+ immune cells towards CCL20, its sole ligand, whose expression is increased during inflammatory processes and is known to play a pivotal role in triggering different autoimmune-mediated inflammatory diseases. Herein, we report a drug discovery effort focused on the development of a new pharmacological approach for the treatment of inflammatory bowel diseases (IBDs) based on small-molecule CCR6 antagonists. The most promising compound 1b was identified by combining in silico studies, sustainable chemistry and in vitro functional/targeted assays, and its efficacy was finally validated in a classic murine model of colitis (TNBS-induced) and in a model of peritonitis (zymosan-induced). These data provide the proof of principle that a pharmacological modulation of the CCL20/CCR6 axis may indeed represent the first step for the development of an orally bioavailable drug candidate for the treatment of IBD and, potentially, other diseases regulated by the CCL20/CCR6 axis., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Masson SAS. All rights reserved.)

Background & Aims: We previously reported that colon epithelial cell silencing of Smad4 increased epithelial expression of inflammatory genes, including the chemokine c-c motif chemokine ligand 20 (CCL20), and increased susceptibility to colitis-associated cancer. Here, we examine the role of the chemokine/receptor pair CCL20/c-c motif chemokine receptor 6 (CCR6) in mediating colitis-associated colon carcinogenesis induced by SMAD4 loss., Methods: In silico analysis of SMAD4, CCL20, and CCR6 messenger RNA expression was performed on published transcriptomic data from human ulcerative colitis (UC), and colon and rectal cancer samples. Immunohistochemistry for CCL20 and CCR6 was performed on human tissue microarrays comprising human UC-associated cancer specimens, Mice with conditional, epithelial-specific Smad4 loss with and without germline deletion of the Ccr6 gene were subjected to colitis and followed for up to 3 months. Tumors were quantified histologically, and immune cell populations were analyzed by flow cytometry and immunostaining., Results: In human UC-associated cancers, loss of epithelial SMAD4 was associated with increased CCL20 expression and CCR6+ cells. SMAD4 loss in mouse colon epithelium led to enlarged gut-associated lymphoid tissues and recruitment of immune cells to the mouse colon epithelium and stroma, particularly T regulatory, T h 17, and dendritic cells. Loss of CCR6 abrogated these immune responses and significantly reduced the incidence of colitis-associated tumors observed with loss of SMAD4 alone., Conclusions: Regulation of mucosal inflammation is central to SMAD4 tumor suppressor function in the colon. A key downstream node in this regulation is suppression of epithelial CCL20 signaling to CCR6 in immune cells. Loss of SMAD4 in the colon epithelium increases CCL20 expression and chemoattraction of CCR6+ immune cells, contributing to greater susceptibility to colon cancer., (Copyright © 2022 AGA Institute. Published by Elsevier Inc. All rights reserved.)

Objective: Chronic pancreatitis (CP) is a potentially fatal disease of the exocrine pancreas, with no specific or effective approved therapies. Due to difficulty in accessing pancreas tissues, little is known about local immune responses or pathogenesis in human CP. We sought to characterise pancreatic immune responses using tissues derived from patients with different aetiologies of CP and non-CP organ donors in order to identify key signalling molecules associated with human CP., Design: We performed single-cell level cellular indexing of transcriptomes and epitopes by sequencing and T-cell receptor (TCR) sequencing of pancreatic immune cells isolated from organ donors, hereditary and idiopathic patients with CP who underwent total pancreatectomy. We validated gene expression data by performing flow cytometry and functional assays in a second patient with CP cohort., Results: Deep single-cell sequencing revealed distinct immune characteristics and significantly enriched CCR6 + CD4 + T cells in hereditary compared with idiopathic CP. In hereditary CP, a reduction in T-cell clonality was observed due to the increased CD4 + T (Th) cells that replaced tissue-resident CD8 + T cells. Shared TCR clonotype analysis among T-cell lineages also unveiled unique interactions between CCR6 + Th and Th1 subsets, and TCR clustering analysis showed unique common antigen binding motifs in hereditary CP. In addition, we observed a significant upregulation of the CCR6 ligand ( CCL20 ) expression among monocytes in hereditary CP as compared with those in idiopathic CP. The functional significance of CCR6 expression in CD4 + T cells was confirmed by flow cytometry and chemotaxis assay., Conclusion: Single-cell sequencing with pancreatic immune cells in human CP highlights pancreas-specific immune crosstalk through the CCR6-CCL20 axis, a signalling pathway that might be leveraged as a potential future target in human hereditary CP., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Endometriosis (EMs) is a common benign gynecological disease that affects approximately 10% of females of reproductive age. Endometriosis ectopic lesions could recruit macrophages, which in turn facilitates endometriosis progression. Several studies have indicated that CCL20 derived from macrophages activates the expression of CCR6 in several cells and induces cell proliferation and migration. However, the function of the CCL20/CCR6 axis in the interactions between macrophages and endometriotic stromal cells (ESCs) in EMs has yet to be elucidated., Methods: Ectopic and normal endometrial tissues were collected from 35 ovarian endometriosis patients and 21 control participants for immunohistochemical staining. It was confirmed that macrophages secreted CCL20 to promote CCR6 activation of ESCs during co-culture by ELISA, qRT-PCR and western blot analysis. CCK8 and Edu assays were used to detect cell proliferation, and wound healing and Transwell assay were used to detect cell migration. Autophagic flux was detected by measuring the protein expression levels of LC3 and P62by western blot and analyzing the red/yellow puncta after ESCs were transfected with mRFP-GFP-LC3 double fluorescence adenovirus (Ad-LC3). Lysosomal function was tested by quantifying the fluorescent intensities of Lyso-tracker and Gal3 and activity of acid phosphatase. In addition, co-IP experiments verified the binding relationship between CCR6 and TFEB. Finally, the suppressive effect of CCL20-NAb on endometriosis lesions in vivo was demonstrated in mice models., Results: We demonstrated that macrophages secreted CCL20 to promote CCR6 activation of ESCs during co-culture, which further induced the proliferation and migration of ESCs. We observed that the CCL20/CCR6 axis impaired lysosomal function and then blocked the autolysosome degradation process of autophagic flux in ESCs. The combination of CCR6 and TFEB to inhibit TFEB nuclear translocation mediates the role of the CCL20/CCR6 axis in the above process. We also found that co-culture with ESCs upregulated the production and secretion of CCL20 by macrophages. The suppression effect of CCL20-NAb on endometriosis lesions in vivo was demonstrated in mice models., Conclusions: Our data indicate that macrophages block TFEB-mediated autolysosome degradation process of autophagic flux in ESCs via the CCL20/CCR6 axis, thereby promoting ESC proliferation and migration., (© 2022. The Author(s).)

Purpose: To investigate the potential mechanisms of miR-211-3p on induction chemotherapy (IC) sensitivity in hypopharyngeal squamous cell carcinoma (HSCC)., Methods: qRT-PCR was assessed to compare the miR-211-3p expression between IC sensitive and insensitive tumor tissues. The MTT assay was performed to analyze cell proliferation and viability to paclitaxel after alteration of miR-211-3p. Flow cytometry assay was conducted to explore cell apoptosis. Transwell assay was used to explore the effect of miR-211-3p on cell migration. Transcriptome sequencing was then performed to select differentially expressed genes (DEGs) after over-expression of miR-211-3p. GO and KEGG enrichment analyses were conducted to annotate DEGs. PPI analysis was conducted to screen candidate genes. The differential expression and survival status of candidate genes were further validated in TCGA-HNSCC data. The single sample GSEA method was used to investigate the association between downstream genes and immune cell infiltration., Results: miR-211-3p was up-regulated in IC insensitive larynx-hypopharyngeal tumor tissues. Over-expression of miR-211-3p promoted cell proliferation and migration, and inhibited apoptosis. The IC 50 value of miR-211-3p overexpression (OE) group was significantly higher than negative control (NC) group treated with paclitaxel, suggesting miR-211-3p enhanced IC insensitivity in HSCC. We found 778 DEG after over-expression of miR-211-3p and 11 significant genes were then identified. Finally, colony stimulating factor 2 (CSF2) and C-C motif chemokine ligand 20 (CCL20) were validated to be significantly high expressed and associated with poorer overall survival in head and neck squamous cell carcinoma, which were involved in TNF signaling pathway and then regulated immune cell infiltration., Conclusion: The miR-211-3p could promote HSCC progression and upregulate CSF2/CCL20/TNF signaling to promote IC insensitivity in HSCC, which may provide new ideas for HSCC therapy., (© 2022. The Author(s), under exclusive licence to Springer Nature B.V.)

C-C motif chemokine ligand 20 (CCL20) participates in multiple oncogenic processes, but its role in lung adenocarcinoma (LUAD) is unclear. Herein, we explored the mechanism by which CCL20 works in LUAD progression. We performed bioinformatical analyses based on the complete transcriptome sequencing data from 1544 LUAD cases in 4 independent cohorts to evaluate signaling pathways regulated by CCL20. We established A549 and H358 cell lines with CCL20 knockdown to explore how CCL20 promotes tumor progression in vitro and in vivo experiments. Using another independent cohort of 348 urothelial carcinoma patients treated with the anti-PD-L1 agent (atezolizumab), we explored the synergistic effect of CCL20 and TGF-β on immunotherapy efficacy. High CCL20 expression is a poor prognostic marker for LUAD patients, and is associated with enhanced epithelial-mesenchymal transition (EMT), inflammatory response, and activated TNF pathway in LUAD. CCL20 knockdown restrained the EMT process and cell proliferation of LUAD cells in vitro and in vivo . Low CCL20 expression blocked the detrimental effects of high TGF-β on survival and effectively improved patients' response to anti-PD-L1 therapy. Collectively, we revealed the underlying mechanisms by which CCL20 promotes LUAD progression based on the largest sample size. The synergistic inhibitory effect of CCL20 and TGF-β on immune-checkpoint blockade therapy efficacy provides new views of immunotherapy resistance., Competing Interests: Competing Interests: The authors have declared that no competing interest exists., (© The author(s).)

Background: The identification of early plasma biomarkers for clinical outcomes and drug resistance has key importance for risk stratification in anaplastic lymphoma kinase (ALK)-positive advanced non-small cell lung cancer (NSCLC) patients. Moreover, it remains unclear whether the anti-angiogenic drug anlotinib can reverse the resistance of ALK-tyrosine kinase inhibitor (ALK-TKI) crizotinib, and no research has explored the effect of anlotinib combined with crizotinib on ALK-positive patients., Methods: In this study, 76 baseline and longitudinal plasma samples from 61 ALK-positive NSCLC patients receiving crizotinib treatment were analyzed by Luminex liquid suspension chip for 40 chemokines. RNA sequence (RNA-seq) was used to identify differentially expressed genes (DEGs) between H3122 and H3122-crizotinib resistant (H3122CR) cells. Tube formation assay was performed to investigate the effect of chemokines on angiogenesis. And H3122CR-derived xenograft model was constructed to validate the efficacy and safety of anlotinib combined with crizotinib in vivo., Results: Baseline and progression plasma samples detection suggested that CCL20 played a crucial role in monitoring and predicting the clinical response of crizotinib (hazard ratio for progression-free survival: 2.27 (1.13-4.58); for overall survival: 2.7 (1.23-5.8)). RNA-seq results for H3122 and H3122CR cells showed that high expression of chemokines and angiogenesis pathways were involved in crizotinib resistance. Subsequently, in vitro experiments indicated that CCL20 may induce crizotinib resistance by activation of angiogenesis via JAK2/STAT3-CCL20-VEGFA/IL6 axis. We further found that anti-angiogenic TKI anlotinib could reverse crizotinib resistance by inhibiting chemokines-induced angiogenesis, and anlotinib combined with crizotinib has a better antitumor effect than monotherapy in vitro & in vivo., Conclusions: Overall, CCL20-mediated angiogenesis is involved in crizotinib resistance and could be overcome by using anlotinib in EML4-ALK positive NSCLC. The combination of anlotinib and crizotinib is a promising strategy for patients resistant to ALK-TKIs., (© 2022. The Author(s).)

The mechanisms through which oral commensal bacteria mitigates uncontrolled inflammatory responses of the oral mucosa remain unknown. Here, we show that representative oral bacterial species normally associated with oral health [S. gordonii ( Sg ), V. parvula ( Vp ), A. naeslundii ( An ), C. sputigena ( Cs ), and N. mucosa ( Nm )] enhanced differential chemokine responses in oral epithelial cells (OECs), with some bacteria ( An, Vp, and Nm ) inducing higher chemokine levels (CXCL1, CXCL8) than others ( Sg, Cs ). Although all bacterial species (except Cs ) increased CCL20 mRNA levels consistent with protein elevations in cell lysates, only An, Vp , and Nm induced higher CCL20 secretion, similar to the effect of the oral pathogen F. nucleatum (Fn) . In contrast, most CCL20 remained associated with OECs exposed to Sg and negligible amounts released into the cell supernatants. Consistently, Sg attenuated An -induced CCL20. MiR-4516 and miR-663a were identified as Sg -specifically induced miRNAs modulating validated targets of chemokine-associated pathways. Cell transfection with miR-4516 and miR-663a decreased An - and Fn -induced CCL20. MiRNA upregulation and attenuation of An -induced CCL20 by Sg were reversed by catalase. Up-regulation of both miRNAs was specifically enhanced by oral streptococci H 2 O 2 -producers. These findings suggest that CCL20 levels produced by OECs in response to bacterial challenge are regulated by Sg -induced miR-4516 and miR-663a in a mechanism that involves hydrogen peroxide. This type of molecular mechanism could partly explain the central role of specific oral streptococcal species in balancing inflammatory and antimicrobial responses given the critical role of CCL20 in innate (antimicrobial) and adaptive immunity (modulates Th17 responses).

Liver metastasis of colorectal cancer (CRLM) is the most common cause of CRC-related mortality, and is typically caused by interactions between CRC cells and the tumour microenvironment (TME) in the liver. However, the molecular mechanisms underlying the crosstalk between tumour-derived extracellular vesicle (EV) miRNAs and the TME in CRLM have yet to be fully elucidated. The present study demonstrated that highly metastatic CRC cells released more miR-181a-5p-rich EVs than cells which exhibit a low metastatic potential, in-turn promoting CRLM. Additionally, we verified that FUS mediated packaging of miR-181a-5p into CRC EVs, which in-turn persistently activated hepatic stellate cells (HSCs) by targeting SOCS3 and activating the IL6/STAT3 signalling pathway. Activated HSCs could secrete the chemokine CCL20 and further activate a CCL20/CCR6/ERK1/2/Elk-1/miR-181a-5p positive feedback loop, resulting in reprogramming of the TME and the formation of pre-metastatic niches in CRLM. Clinically, high levels of serum EV containing miR-181a-5p was positively correlated with liver metastasis in CRC patients. Taken together, highly metastatic CRC cells-derived EVs rich in miR-181a-5p could activate HSCs and remodel the TME, thereby facilitating liver metastasis in CRC patients. These results provide novel insight into the mechanism underlying liver metastasis in CRC., (© 2022 The Authors. Journal of Extracellular Vesicles published by Wiley Periodicals, LLC on behalf of the International Society for Extracellular Vesicles.)

Developing new adjuvants/vaccines and better understanding their mode-of-action is an important task. To specifically improve birch pollen allergy treatment, we designed a fusion protein consisting of major birch pollen allergen Betv1 conjugated to the TLR5-ligand flagellin (rFlaA:Betv1). This study investigates the immune-modulatory effects of rFlaA:Betv1 on airway epithelial cells. LA-4 mouse lung epithelial cells were stimulated with rFlaA:Betv1 in the presence/absence of various inhibitors with cytokine- and chemokine secretion quantified by ELISA and activation of intracellular signaling cascades demonstrated by Western blot (WB). Either LA-4 cells or LA-4-derived supernatants were co-cultured with BALB/c bone marrow-derived myeloid dendritic cells (mDCs). Compared to equimolar amounts of flagellin and Betv1 provided as a mixture, rFlaA:Betv1 induced higher secretion of IL-6 and the chemokines CCL2 and CCL20 from LA-4 cells and a pronounced MAPK- and NF κ B-activation. Mechanistically, rFlaA:Betv1 was taken up more strongly and the induced cytokine production was inhibited by NF κ B-inhibitors, while ERK- and p38-MAPK-inhibitors only suppressed IL-6 and CCL2 secretion. In co-cultures of LA-4 cells with mDCs, rFlaA:Betv1-stimulated LA-4 cells p38-MAPK- and COX2-dependently secreted PGE 2 , which modulated DC responses by suppressing pro-inflammatory IL-12 and TNF-α secretion. Taken together, these results contribute to our understanding of the mechanisms underlying the strong immune-modulatory effects of flagellin-containing fusion proteins.

Breast cancer is the leading cause of cancer-related death among women despite the significant improvement in diagnosis and treatment. Tumor-associated neutrophils have been shown to suppress antitumor functions of the host. However, how breast cancer tumor microenvironment influences the phenotype and functions of neutrophils to potentiate T cell immunosuppression is unknown. Herein, neutrophils isolated from peripheral blood of healthy donors were treated with supernatants from breast cancer cell lines or recombinant human CCL20. PD-L1 expression on neutrophils was then evaluated by immunofluorescence and flow cytometry. Neutrophils and Jurkat T cells were cocultured to evaluate the effect of tumor-associated neutrophils on T cell functions. Finally, immunohistochemical staining was performed to evaluate the clinical relevance of neutrophils infiltrating breast tumor tissues. Tumor-derived CCL20 activated and upregulated PD-L1 expression on neutrophils. A significant positive correlation was found between CCL20 and CD66b+ neutrophils in tumor tissues. Through in vitro experiment, tumor-associated neutrophils (TANs) effectively suppressed T cell immunity which was reversed upon PD-L1 blockade.Moreover, a high density of TANs was associated with short disease free survival in breast cancer patients. Furthermore, receiver operating curve showed that the density of TANs could accurately predict disease-free survival in breast cancer patients. Our findings suggest that targeting TANs via CCL20 immunosuppressive pathway may be a novel therapeutic strategy for breast cancer treatment.

Bone metastases are devastating complications of cancer. They are particularly common in prostate cancer (PCa), represent incurable disease, and are refractory to immunotherapy. We seek to define distinct features of the bone marrow (BM) microenvironment by analyzing single cells from bone metastatic prostate tumors, involved BM, uninvolved BM, and BM from cancer-free, orthopedic patients, and healthy individuals. Metastatic PCa is associated with multifaceted immune distortion, specifically exhaustion of distinct T cell subsets, appearance of macrophages with states specific to PCa bone metastases. The chemokine CCL20 is notably overexpressed by myeloid cells, as is its cognate CCR6 receptor on T cells. Disruption of the CCL20-CCR6 axis in mice with syngeneic PCa bone metastases restores T cell reactivity and significantly prolongs animal survival. Comparative high-resolution analysis of PCa bone metastases shows a targeted approach for relieving local immunosuppression for therapeutic effect., Competing Interests: Declaration of interests P.V.K. serves on the Scientific Advisory Board to Celsius Therapeutics Inc. and Biomage Inc. D.T.S. is a director and shareholder for Agios Therapeutics and Editas Medicines; a founder, director, shareholder, and scientific advisory board member for Magenta Therapeutics and LifeVault Bio, a shareholder and founder of Fate Therapeutics, and a director, founder, and shareholder for Clear Creek Bio, a consultant for FOG Pharma and VCanBio, and a recipient of sponsored research funding from Novartis. D.B.S. is a founder, consultant, and shareholder for Clear Creek Bio., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Cancer cells experience endoplasmic reticulum (ER) stress due to activated oncogenes and conditions of nutrient deprivation and hypoxia. The ensuing unfolded protein response (UPR) is executed by ATF6, IRE1 and PERK pathways. Adaptation to mild ER stress promotes tumor cell survival and aggressiveness. Unmitigated ER stress, however, will result in cell death and is a potential avenue for cancer therapies. Because of this yin-yang nature of ER stress, it is imperative that we fully understand the mechanisms and dynamics of the UPR and its contribution to the complexity of tumor biology. The PERK pathway inhibits global protein synthesis while allowing translation of specific mRNAs, such as the ATF4 transcription factor. Using thapsigargin and tunicamycin to induce acute ER stress, we identified the transcription factor C/EBPδ (CEBPD) as a mediator of PERK signaling to secretion of tumor promoting chemokines. In melanoma and breast cancer cell lines, PERK mediated early induction of C/EBPδ through ATF4-independent pathways that involved at least in part Janus kinases and the STAT3 transcription factor. Transcriptional profiling revealed that C/EBPδ contributed to 20% of thapsigargin response genes including chaperones, components of ER-associated degradation, and apoptosis inhibitors. In addition, C/EBPδ supported the expression of the chemokines CXCL8 (IL-8) and CCL20, which are known for their tumor promoting and immunosuppressive properties. With a paradigm of short-term exposure to thapsigargin, which was sufficient to trigger prolonged activation of the UPR in cancer cells, we found that conditioned media from such cells induced cytokine expression in myeloid cells. In addition, activation of the CXCL8 receptor CXCR1 during thapsigargin exposure supported subsequent sphere formation by cancer cells. Taken together, these investigations elucidated a novel mechanism of ER stress-induced transmissible signals in tumor cells that may be particularly relevant in the context of pharmacological interventions., (© 2021. This is a U.S. government work and not under copyright protection in the U.S.; foreign copyright protection may apply.)

Numerous studies have reported that a variety of long noncoding RNAs (lncRNAs) can promote the proliferation, invasion, and migration of different tumor cells. However, different lncRNAs regulate cell functions in various forms, and the exact mechanisms are not clear. Here, we investigated the effect of the lncRNA ELF3-AS1 on gastric cancer (GC) cell function and explored the exact mechanism. Quantitative real-time polymerase chain reaction was used to detect the expression of ELF3-AS1 in GC tissues and adjacent nontumor tissues. Knockdown and overexpression of ELF3-AS1 was used to detect the effect of ELF3-AS1 on cell function. Potential downstream target genes were identified using RNA transcriptome sequencing, while RNA immunoprecipitation, chromatin immunoprecipitation, and Western blotting were performed to explore the tumor promotion mechanisms of ELF3-AS1. We observed that ELF3-AS1 was highly expressed in GC tissues, and high ELF3-AS1 expression predicted poor prognosis. The knockdown of ELF3-AS1 significantly inhibited cell proliferation, migration, and epithelial-mesenchymal transition and promoted apoptosis. Mechanistic investigations revealed that ELF3-AS1 may regulate the downstream target gene, C-C motif chemokine 20, by binding with the RNA-binding protein hnRNPK. Additionally, we found that high ELF3-AS1 expression was associated with thrombocytosis. Interleukin-6 and thrombopoietin may be involved in ELF3-AS1-induced paraneoplastic thrombocytosis. Together, our results demonstrate that aberrantly expressed ELF3-AS1 in GC may play important roles in oncogenesis and progression and is expected to become a new target for the diagnosis and treatment of GC., (© 2021 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.)

Fusobacterium nucleatum is a ubiquitous opportunistic pathogen with an emerging role as an oncomicrobe in colorectal cancer and other cancer settings. F. nucleatum can adhere to and invade host cells in a manner that varies across F. nucleatum strains and host cell phenotypes. Here, we performed pairwise cocultures between three F. nucleatum strains and two immortalized primary host cell types (human colonic epithelial [HCE] cells and human carotid artery endothelial [HCAE] cells) followed by transcriptome sequencing (RNA-seq) and chromatin immunoprecipitation sequencing (ChIP-seq) to investigate transcriptional and epigenetic host cell responses. We observed that F. nucleatum-induced host cell transcriptional modulation involves strong upregulation of genes related to immune migration and inflammatory processes, such as TNF , CXCL8 , CXCL1 , and CCL20 . Furthermore, we identified genes strongly upregulated in a cell line-specific manner. In HCE cells, overexpressed genes included UBD and DUOX2 / DUOXA2 , associated with p53 degradation-mediated proliferation and intestinal reactive oxygen species (ROS) production, respectively. In HCAE cells, overexpressed genes included EFNA1 and LIF , two genes commonly upregulated in colorectal cancer and associated with poor patient outcomes, and PTGS2 ( COX2 ), a gene associated with the protective effect of aspirin in the colorectal cancer setting. Interestingly, we also observed downregulation of numerous histone modification genes upon F. nucleatum exposure. We used the ChIP-seq data to annotate chromatin states genome wide and found significant chromatin remodeling following F. nucleatum exposure in HCAE cells, with increased frequencies of active enhancer and low-signal/quiescent states. Thus, our results highlight increased inflammation and chemokine gene expression as conserved host cell responses to F. nucleatum exposure and extensive host cell epigenomic changes specific to host cell type. IMPORTANCE Fusobacterium nucleatum is a bacterium normally found in the healthy oral cavity but also has an emerging role in colorectal cancer and other cancer settings. The host-microbe interactions of F. nucleatum and its involvement in tumor initiation, progression, and treatment resistance are not fully understood. We explored host cell changes that occur in response to F. nucleatum. We identified key genes differentially expressed in response to various conditions of F. nucleatum exposure and determined that the conserved host cell response to F. nucleatum was dominated by increased inflammation and chemokine gene expression. Additionally, we found extensive host cell epigenomic changes as a novel aspect of host modulation associated with F. nucleatum exposure. These results extend our understanding of F. nucleatum as an emerging pathogen and highlight the importance of considering strain heterogeneity and host cell phenotypic variation when exploring pathogenic mechanisms of F. nucleatum.

Schizophrenia (SZ) and major depressive disorder (MDD) are severe mental disorders, which have been associated with alterations of the peripheral inflammatory network. However, studies for both disorders have not been fully consistent and have focused on few canonical markers with high relevance to the innate immune system, while the role of the adaptive immune system is studied less. Furthermore, it is unclear to what extent inflammatory abnormalities are diagnosis-specific or transdiagnostic. The purpose of this study was to investigate 75 peripheral inflammatory markers including the acute phase protein high-sensitivity C-reactive protein (hsCRP) in patients with MDD (n = 37), SZ (n = 42) and healthy controls (HC) (n = 17), while considering possible confounders and correcting rigorously for multiple testing in group comparisons. We identified C-C chemokine ligand 20 (CCL20) and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) as the inflammatory markers with significant group differences after controlling for multiple comparisons and adjusting for BMI, sex and smoking as confounders. TRAIL was elevated in both MDD and SZ compared to HC. CCL20 was specifically increased in SZ compared to MDD and HC. There were no significant group differences in hsCRP after correcting for multiple testing. Finally, we observed no significant correlations among CCL20, TRAIL and CRP. TRAIL is a transdiagnostic marker for SZ and MDD, with both markers being independent from CRP and body mass index (BMI). CCL20 may be a novel and specific biomarker of schizophrenia, but an influence of antipsychotic medication cannot be excluded. Identifying novel markers in mental disease bears the potential for future research towards novel treatment strategies by modifying inflammation-related processes., (© 2021. The Author(s).)

Background: CD146 is a tight junction-associated molecule involved in maintaining endothelial barrier, and balancing immune-inflammation response, in cardiovascular disease. Notably, peripheral CD146 + cells significantly upsurge under vessel dyshomeostasis such as acute myocardial injury (AMI), appearing to be a promising therapeutic target. In this study, with a new view of gene correlation, we aim at deciphering the complex underlying mechanism of CD146 + cells' impact in the development of AMI., Methods: Transcription dataset GSE 66,360 of CD146 + blood cells from clinical subjects was downloaded from NCBI. Pearson networks were constructed and the clustering coefficients were calculated to disclose the differential connectivity genes (DCGs). Analysis of gene connectivity and gene expression were performed to reveal the hub genes and hub gene clusters followed by gene enrichment analysis., Results and Conclusions: Among the total 23,520 genes, 27 genes out of 126 differential expression genes were identified as DCGs. These DCGs were found in the periphery of the networks under normal condition, but transferred to the functional center after AMI. Moreover, it was revealed that DCGs spontaneously crowded together into two functional models, CCL20 cluster and NR4A3 cluster, influencing the CD146-mediated signaling pathways during the pathology of AMI for the first time., (© 2021. The Author(s).)

Dipeptidyl peptidase 4 (DPP4) expression is increased in the lungs of chronic obstructive pulmonary disease (COPD). DPP4 is known to be associated with inflammation in various organs, including LPS-induced acute lung inflammation. Since non-typeable Haemophilus influenzae (NTHi) causes acute exacerbations in COPD patients, we examined the contribution of DPP4 in NTHi-induced lung inflammation in COPD. Pulmonary macrophages isolated from COPD patients showed higher expression of DPP4 than the macrophages isolated from normal subjects. In response to NTHi infection, COPD, but not normal macrophages show a further increase in the expression of DPP4. COPD macrophages also showed higher expression of IL-1β, and CCL3 responses to NTHi than normal, and treatment with DPP4 inhibitor, diprotin A attenuated this response. To examine the contribution of DPP4 in NTHi-induced lung inflammation, COPD mice were infected with NTHi, treated with diprotin A or PBS intraperitoneally, and examined for DPP4 expression, lung inflammation, and cytokine expression. Mice with COPD phenotype showed increased expression of DPP4, which increased further following NTHi infection. DPP4 expression was primarily observed in the infiltrated inflammatory cells. NTHi-infected COPD mice also showed sustained neutrophilic lung inflammation and expression of CCL3, and this was inhibited by DPP4 inhibitor. These observations indicate that enhanced expression of DPP4 in pulmonary macrophages may contribute to sustained lung inflammation in COPD following NTHi infection. Therefore, inhibition of DPP4 may reduce the severity of NTHi-induced lung inflammation in COPD., (© 2021 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.)