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Background Calcitonin gene-related peptide (CGRP), an immunomodulatory neuropeptide, is important for regulating pain transmission, vasodilation, and the inflammatory response. However, the molecular mechanisms of the CGRP-mediated immune response remain unknown. Methods The effects of CGRP on bacterial meningitis (BM) and its underlying mechanisms were investigated in BM mice in vivo and macrophages in vitro. Results Peripheral injection of CGRP attenuated cytokine storms and protected mice from fatal pneumococcal meningitis, marked by increased bacterial clearance, improved neuroethology, and reduced mortality. When the underlying mechanisms were investigated, we found that CGRP induces proteasome-dependent degradation of major histocompatibility complex class II (MHC-II) in macrophages and then inhibits CD4+ T-cell activation. MARCH1 was identified as an E3 ligase that can be induced by CGRP engagement and promote K48-linked ubiquitination and degradation of MHC-II in macrophages. These results provide new insights into neuropeptide CGRP-mediated immune regulation mechanisms. Conclusions We conclude that targeting the nervous system and manipulating neuroimmune communication is a promising strategy for treating intracranial infections like BM. [ABSTRACT FROM AUTHOR]

Chemotherapy-induced neuropathic pain (CIPN) is a common side effect of antitumor chemotherapeutic agents. It describes a pathological state of pain related to the cumulative dosage of the drug, significantly limiting the efficacy of antitumor treatment. Sofas strategies alleviating CIPN still lack. Calcitonin gene-related peptide (CGRP) is a neuropeptide involved in many pathologic pains. In this study, we explored the effects of CGRP blocking on CIPN and potential mechanisms. Total dose of 20.7 mg/kg cisplatin was used to establish a CIPN mouse model. Mechanical and thermal hypersensitivity was measured using von Frey hairs and tail flick test. Western blot and immunofluorescence were utilized to evaluate the levels of CGRP and activated astrocytes in mouse spinal cord, respectively. In addition, real-time quantitative PCR (RT-qPCR) was used to detect the level of inflammatory cytokines such as IL-6, IL-1β, and NLRP3 in vitro and in vivo. There are markedly increased CGRP expression and astrocyte activation in the spinal cord of mice following cisplatin treatment. Pretreatment with a monoclonal antibody targeting CGRP (ZR8 mAb) effectively reduced cisplatin-induced mechanical hypersensitivity and thermal nociceptive sensitization and attenuated neuroinflammation as marked by downregulated expression of IL-6, IL-1β, and NLRP3 in the mice spinal cord and spleen. Lastly, ZR8 mAb does not interfere with the antitumor effects of cisplatin in tumor-bearing mice. Our findings indicate that neutralizing CGRP with monoclonal antibody could effectively alleviate CIPN by attenuating neuroinflammation. CGRP is a promising therapeutic target for CIPN. [ABSTRACT FROM AUTHOR]

Little is known about the distribution of etiology in obstructive sleep apnea (OSA) combined with chronic breathlessness. A significant portion of patients in this group have so-called "overlap syndrome (OVS)", characterized by chronic obstructive pulmonary disease (COPD). OVS has more complications and a poorer prognosis compared to patients with either OSA or COPD alone, which makes it important to identify OVS early in OSA. The current study was a retrospective cross-sectional analysis of consecutive adult patients who were diagnosed with OSA (n = 1062), of whom 275 were hospitalized due to chronic breathlessness. Respiratory and cardiac diseases accounted for the vast majority of causes, followed by gastrointestinal and renal disorders. The final study population comprised 115 patients with OSA alone (n = 64) and OVS (n = 51), who had chronic breathlessness as the primary complaint, not secondary as one of many other complaints. Lymphocytes, CD4 counts, neutrophil-to-lymphocyte ratio (NLR), and PLR were differently expressed between the OSA-alone group and OVS group. The NLR, lymphocytes, and CD4 counts had a moderate diagnostic value for OVS in OSA patients, with AUCs of 0.708 (95% CI, 0.614–0.802), 0.719 (95% CI, 0.624–0.813), and 0.744 (95% CI, 0.653–0.834), respectively. The NLR had the highest AUC for predicting a 6-month re-admission of OVS, with a cut-off of 3.567 and a moderate prognostic value. The sensitivity and specificity were 0.8 and 0.732, respectively. In the animal model, the spleen hematoxylin- and eosin-stained, electron microscopy images showed germinal-center damage, chromatin activation, and mitochondrial swelling under the overlapping effect of intermittent hypoxia and cigarette smoke exposure. OSA with chronic breathlessness cannot be overstated. A significant proportion of patients with COPD in this group had poor lung function at initial diagnosis. The NLR is a useful biomarker to differentiate OVS among OSA patients combined with chronic breathlessness. [ABSTRACT FROM AUTHOR]

The mechanisms by which retinoic acid-inducible gene I (RIG-I), a critical RNA virus sensor, is regulated in many biological and pathological processes remain to be determined. Here, we demonstrate that T cell immunoglobulin and mucin protein-3 (Tim-3), an immune checkpoint inhibitor, mediates infection tolerance by suppressing RIG-I-type I interferon pathway. Overexpression or blockade of Tim-3 affects type I interferon expression, virus replication, and tissue damage in mice following H1N1 infection. Tim-3 signaling decreases RIG-I transcription via STAT1 in macrophages and promotes the proteasomal dependent degradation of RIG-I by enhancing K-48-linked ubiquitination via the E3 ligase RNF-122. Silencing RIG-I reversed Tim-3 blockage-mediated upregulation of type I interferon in macrophages. We thus identified a new mechanism through which Tim-3 mediates the immune evasion of H1N1, which may have clinical implications for the treatment of viral diseases. [ABSTRACT FROM AUTHOR]

Acute myeloid leukemia (AML), a malignant disorder of hemopoietic stem cells. AML can escape immunosurveillance of natural killer (NK) by gene mutation, fusions, and epigenetic modification, while the mechanism is not clearly understood. Here we show that the expression of Intercellular adhesion molecule‐1 (ICAM‐1, CD54) is silenced in AML cells. Decitabine could upregulate ICAM-1 expression, which contributes to the NK-AML cell conjugates and helps NK cells kill AML cells. We also show that ICAM-1 high expression can reverse the AML immune evasion and activate NK cells function in vivo. This study suggests that a combination of the hypomethylating agent and NK cell infusion could be a new strategy to cure AML. [ABSTRACT FROM AUTHOR]

Viral encephalitis is the most common cause of encephalitis. It is responsible for high morbidity rates, permanent neurological sequelae, and even high mortality rates. The host immune response plays a critical role in preventing or clearing invading pathogens, especially when effective antiviral treatment is lacking. However, due to blockade of the blood-brain barrier, it remains unclear how peripheral immune cells contribute to the fight against intracerebral viruses. Here, we report that peripheral injection of an antibody against human Tim-3, an immune checkpoint inhibitor widely expressed on immune cells, markedly attenuated vesicular stomatitis virus (VSV) encephalitis, marked by decreased mortality and improved neuroethology in mice. Peripheral injection of Tim-3 antibody enhanced the recruitment of immune cells to the brain, increased the expression of major histocompatibility complex-I (MHC-I) on macrophages, and as a result, promoted the activation of VSV-specific CD8+ T cells. Depletion of macrophages abolished the peripheral injection-mediated protection against VSV encephalitis. Notably, for the first time, we found a novel post-translational modification of MHC-I by Tim-3, wherein, by enhancing the expression of MARCH9, Tim-3 promoted the proteasome-dependent degradation of MHC-I via K48-linked ubiquitination in macrophages. These results provide insights into the immune response against intracranial infections; thus, manipulating the peripheral immune cells with Tim-3 antibody to fight viruses in the brain may have potential applications for combating viral encephalitis. [ABSTRACT FROM AUTHOR]

T cell immunoglobulin and mucin protein 3 (Tim-3) is an immune checkpoint and plays a vital role in immune responses during acute myeloid leukemia (AML). Targeting Tim-3 kills two birds with one stone by balancing the immune system and eliminating leukemia stem cells (LSCs) in AML. These functions make Tim-3 a potential target for curing AML. This review mainly discusses the roles of Tim-3 in the immune system in AML and as an AML LSC marker, which sheds new light on the role of Tim-3 in AML immunotherapy. [ABSTRACT FROM AUTHOR]

The t(8;21)(q22;q22) translocation is the most common chromosomal translocation in acute myeloid leukemia (AML), and it gives rise to acute myeloid gene 1 (AML1)-myeloid transforming gene 8 (ETO)-positive AML, which has a relatively favorable prognosis. CD48 is a favorable prognosis factor that is downregulated in AML patients. AML can escape immunosurveillance of natural killer (NK) cells by decreasing CD48 expression. The correlation between AML1-ETO and CD48-mediated immune evasion is not well understood. Here, we show that AML1-ETO can increase CD48 expression, which is regulated by AML1-ETO/P300-mediated acetylation. AML1-ETO can inhibit AML immune escape from NK cell recognition and killing by increasing CD48 expression. This study describes a novel mechanism by which AML1-ETO can inhibit AML immune escape by increasing CD48 acetylation, thereby providing new evidence about AML patients with AML1-ETO oncogene infusion having better clinical outcomes. [ABSTRACT FROM AUTHOR]

T cell immunoglobulin and mucin domain‐3 (Tim‐3), an immune checkpoint molecule, plays critical roles in maintaining innate immune homeostasis; however, the mechanisms underlying these roles remain to be determined. Here, we determined that Tim‐3 controls glycolysis in macrophages and thus contributes to phenotype shifting. Tim‐3 signal blockade significantly increases lactate production by macrophages, but does not influence cell proliferation or apoptosis. Tim‐3 attenuates glucose uptake by inhibiting hexokinase 2 (HK2) expression in macrophages. Tim‐3‐mediated inhibition of macrophage glycolysis and the expression of proinflammatory cytokines, tumour necrosis factor (TNF)‐α and interleukin (IL)‐1β are reversed by HK2 silencing. Finally, we demonstrated that Tim‐3 inhibits HK2 expression via the STAT1 pathway. We have thus discovered a new way by which Tim‐3 modulates macrophage function. [ABSTRACT FROM AUTHOR]

Lymphocyte apoptosis appears to play an important role in immunodysfunction in sepsis. We investigated the role of miR-223 in cell proliferation and apoptosis to identify potential target downstream proteins in sepsis. We recruited 143 patients with sepsis and 44 healthy controls from the Chinese PLA General Hospital. Flow cytometry was used to sort monocytes, lymphocytes, and neutrophils from fresh peripheral blood. A miR-223 mimic and inhibitor were used for transient transfection of Jurkat T cells. Quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) was used to assess expression of the miRNAs in cells. Western blot analysis was performed to measure protein expression. We evaluated the cell cycle and apoptosis by using flow cytometry (FCM) and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL). Expression of miR-223 was significantly higher in the survivor group than in the nonsurvivor group. Multiple linear regression analysis revealed that SOFA scores correlated negatively with miR-223 and monocyte counts, with β coefficients (95% CI) of − 0.048 (− 0.077, − 0.019) and − 47.707 (− 83.871, − 11.543), respectively. miR-223 expression also correlated negatively with the percentage of apoptosis in lymphocytes. The rate of apoptosis in the miR-223 mimic group was significantly lower than that of the negative control, with an adverse outcome observed in the miR-223 inhibitor group. We also found that miR-223 enhanced the proliferation of Jurkat T cells and that inhibiting miR-223 had an inhibitory effect on the G1/S transition. We conclude that miR-223 can serve as a protective factor in sepsis by reducing apoptosis and enhancing cell proliferation in lymphocytes by interacting with FOXO1. Potential downstream molecules are HSP60, HSP70, and HTRA. [ABSTRACT FROM AUTHOR]

Background: T-cell immunoglobulin and mucin protein 3 (Tim-3) is an immune checkpoint inhibitor that has therapeutic implications for many tumors and infectious diseases. However, the mechanisms by which Tim-3 promotes immune evasion remain unclear.Methods: In this study, we demonstrated that Tim-3 inhibits the expression of major histocompatibility complex class I (MHC-I) in macrophages at both the messenger ribonucleic acid and protein levels by inhibiting the STAT1-NLRC5 signaling pathway.Results: As a result, MHC-I-restricted antigen presentation by macrophages was inhibited by Tim-3 both in vitro and in a Listeria monocytogenes infection model in vivo. Systemic overexpression of Tim-3 or specific knockout of Tim-3 in macrophages significantly attenuated or enhanced CD8+ T-cell activation and infection damage in L monocytogenes-infected mice, respectively.Conclusions: Thus, we identified a new mechanism by which Tim-3 promotes L monocytogenes immune evasion. Further studies on this pathway might shed new light on the physio-pathological roles of Tim-3 and suggest new approaches for intervention. [ABSTRACT FROM AUTHOR]

The Nod-like receptor protein 3 ( NLRP3) inflammasome plays roles in host defence against invading pathogens and in the development of autoimmune damage. Strict regulation of these responses is important to avoid detrimental effects. Here, we demonstrate that T cell Ig mucin-3 (Tim-3), an immune checkpoint inhibitor, inhibits NLRP3 inflammasome activation by damping basal and lipopolysaccharide-induced nuclear factor- κB-mediated up-regulation of NLRP3 and interleukin-1 β during the priming step and basal and ATP/lipopolysaccharide-induced ATP production, K+ efflux, and reactive oxygen species production during the activation step. Residues Y256/Y263 in the C-terminal region of Tim-3 are required for these inhibitory effects on the NLRP3 inflammasome. In mice with alum-induced peritonitis, blockade of Tim-3 exacerbates peritonitis by overcoming the inhibitory effect of Tim-3 on NLRP3 inflammasome activation, while transgenic expression of Tim-3 attenuates inflammation by inhibiting NLRP3 inflammasome activation. Our results show that Tim-3 is a critical negative regulator of NLRP3 inflammasome and provides a potential target for intervention of diseases with uncontrolled inflammasome activation. [ABSTRACT FROM AUTHOR]

The interleukin (IL).12 family cytokines have been examined as therapeutic targets in the treatment of several autoimmune diseases. Our previous study showed that a novel IL.12 family cytokine, IL.39 (IL.23p19/Ebi3) mediates inflammation in lupus.like mice. In the present study, the effect of anti.mouse IL.39 polyclonal antibodies on autoimmune symptoms in lupus.like mice was investigated. Rabbit anti.mouse IL.39 polyclonal antibodies were produced by immunization with recombinant mouse IL.39, and purified using protein A chromatography. These antibodies were subsequently used to treat lupus.like mice. Flow cytometry, captured images, ELISA and H&E staining were used to determine the effect of anti.IL.39 polyclonal antibodies on inflammatory cells, autoantibody titers, proteinuria, infiltrating inflammatory cells and the structure of the glomerular region. The anti.IL.39 polyclonal antibodies effectively reduced the numbers of inflammatory cells, splenomegaly, autoantibody titers, proteinuria, infiltrating inflammatory cells, and restored the structure of the glomerular region in MRL/lpr mice. Taken together, these results suggested that anti.IL.39 polyclonal antibodies ameliorated autoimmune symptoms in lupus.like mice. Therefore, IL.39 may be used as a possible target for the treatment of systemic lupus erythematosus. [ABSTRACT FROM AUTHOR]

Interleukin-10-positive (IL-10+) regulatory B (Breg) cells play an important role in restraining excessive inflammatory responses by secreting IL-10. However, it is still unclear what key transcription factors determine Breg cell differentiation. Hence, we explore what transcription factor plays a key role in the expression of IL-10, a pivotal cytokine in Breg cells. We used two types of web-based prediction software to predict transcription factors binding the IL-10 promoter and found that IL-10 promoter had many binding sites for Foxd3. Chromatin immunoprecipitation PCR assay demonstrated that Foxd3 directly binds the predicted binding sites around the start codon upstream by −1400 bp. Further, we found that Foxd3 suppressed the activation of IL-10 promoter by using an IL-10 promoter report system. Finally, knocking out Foxd3 effectively promotes Breg cell production by up-regulating IL-10 expression. Conversely, up-regulated Foxd3 expression was negatively associated with IL-10+ Breg cells in lupus-prone MRL/lpr mice. Hence, our data suggest that Foxd3 suppresses the production of IL-10+ Breg cells by directly binding the IL-10 promoter. This study demonstrates the mechanism for Breg cell production and its application to the treatment of autoimmune diseases by regulating Foxd3 expression. [ABSTRACT FROM AUTHOR]

T cell immunoglobulin and mucin domain protein 3 (Tim‐3) is an immune checkpoint inhibitor in T cells and innate immune cells. The deregulated upregulation of Tim‐3 is related to immune exhaustion in tumour and viral infection. To overcome Tim‐3‐mediated immune tolerance, we developed a novel monoclonal antibody against human Tim‐3 (L3G) and investigated its roles in inhibiting Tim‐3 signalling and overcoming immune tolerance in T cells and monocytes/macrophages. The administration of L3G to cultured peripheral blood mononuclear cells (PBMCs) significantly increased the production of IFN‐γ and IL‐2 and the expression of type I interferon. The administration of L3G also increased the production of IFN‐γ, IL‐8 and type I interferon in U937 cells and primary monocytes. We investigated the mechanisms by which L3G enhances pro‐inflammatory cytokine expression, and our data show that L3G enhances STAT1 phosphorylation in both monocytes/macrophages and T cells. Finally, in an H1N1 infection model of PBMCs and U937 cells, L3G decreased the viral load and enhanced the expression of interferon. Thus, we developed a functional antibody with therapeutic potential against Tim‐3‐mediated infection tolerance. [ABSTRACT FROM AUTHOR]

The E3 ubiquitin ligase Itch interacts with Foxo1 and targets it for ubiquitination and degradation during follicular helper T-cell differentiation, whereas the transcription factor Foxo1 plays a critical role in B-cell development. Thus, we proposed that Itch mediates B-cell differentiation. Unexpectedly, we found that Itch deficiency downregulated Foxo1 expression in B cells. Itch cKO (conditional knock out in B cells) mice had fewer pro-B cells in the bone marrow, more small resting IgM−IgD−B cells in the periphery, and lower B-cell numbers in the lymph nodes through decreased Foxo1-mediated IL-7Rα, RAG, and CD62L expression, respectively. Importantly, Itch deficiency reduced Foxo1 mRNA expression by up-regulating JunB-mediated miR-182. Finally, Foxo1 negatively regulated JunB expression by up-regulating Itch. Thus, we have identified a novel regulatory axis between Itch and Foxo1 in B cells, suggesting that Itch is essential for B-cell development. [ABSTRACT FROM AUTHOR]

T cell immunoglobulin mucin-3 (Tim-3) is an immune checkpoint inhibitor and its dysregulation has been related to T cell tolerance and many immune disorders, such as tumors and infection tolerance. However, the physiopathology roles of Tim-3 in innate immunity remain elusive. Here, we demonstrate that Tim-3 inhibits macrophage phagocytosis of L. monocytogenes by inhibiting the nuclear erythroid 2-related factor 2 (Nrf2) signaling pathway and increases bacterial burden. Tim-3 signaling promotes Nrf2 degradation by increasing its ubiquitination and, as a result, decreasing its nuclear translocation. CD36 and heme oxygenase-1 (HO-1), two downstream molecules in the Tim-3-Nrf2 signaling axis, are involved in the Tim-3- mediated immune evasion of L. monocytogenes both in vitro and in vivo. We here identified new mechanisms by which Tim-3 induces infection tolerance. By modulating the Tim-3 pathway, we demonstrate the feasibility of manipulating macrophage function as a potent tool for treating infectious diseases, such as Listeria infection. [ABSTRACT FROM AUTHOR]