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Villous cytotrophoblast (vCTB) cells fuse to generate and maintain the syncytiotrophoblast layer required for placental development and function. Krüppel-like factor 6 (KLF6) is a ubiquitous transcription factor with an N-terminal acidic transactivation domain and a C-terminal zinc finger DNA-binding domain. KLF6 is highly expressed in placenta, and it is required for proper placental development. We have demonstrated that KLF6 is necessary for cell fusion in human primary vCTBs, and in the BeWo cell line.Full length KLF6 or a mutant lacking its N-terminal domain were expressed in BeWo cells or in primary vCTB cells isolated from human term placentas. Cell fusion, gene and protein expression, and cell proliferation were analyzed. Moreover, Raman spectroscopy and atomic force microscopy (AFM) were used to identify biochemical, topography, and elasticity cellular modifications.The increase in KLF6, but not the expression of its deleted mutant, is sufficient to trigger cell fusion and to raise the expression of β-hCG, syncytin-1, the chaperone protein 78 regulated by glucose (GRP78), the ATP Binding Cassette Subfamily G Member 2 (ABCG2), and Galectin-1 (Gal-1), all molecules involved in vCTB differentiation. Raman and AFM analysis revealed that KLF6 reduces NADH level and increases cell Young's modulus. KLF6-induced differentiation correlates with p21 upregulation and decreased cell proliferation. Remarkable, p21 silencing reduces cell fusion triggered by KLF6 and the KLF6 mutant impairs syncytialization and decreases syncytin-1 and β-hCG expression.KLF6 induces syncytialization through a mechanism that involves its regulatory transcriptional domain in a p21-dependent manner.

Aims/hypothesis Non-alcoholic fatty liver disease (NAFLD) is frequently associated with type 2 diabetes mellitus. Progression of NAFLD is mediated, among other things, by activation of inflammatory pathways. In the present study, the role of the proinflammatory cytokine LIGHT (TNFSF14) was explored in NAFLD and type 2 diabetes mellitus in mice deficient for the cytokine. Methods Light-deficient (Light-/-) mice and WT controls were fed a regular chow diet (RCD) or a high-fat high-cholesterol diet (HFHCD) for 16 weeks. The expression of LIGHT and its receptors, herpes virus entry mediator (HVEM) and lymphotoxin β receptor (LTβR), was investigated in both dietary regimens. Glucose tolerance, insulin sensitivity, non-alcoholic fatty liver (NAFL), systemic and tissue inflammation, and metabolic gene expression were explored in Light-/- and WT mice fed an RCD and an HFHCD. The effect of Light deficiency was also evaluated in hepatic tissue and in inflammation in HFHCD-fed Irs2+/- mice with impaired insulin signalling. Results Light deficiency did not have an effect on metabolism, in NAFL or in tissue and systemic inflammation, in RCD-fed WT mice. HVEM and LTβR were markedly increased in livers of HFHCD-fed WT mice compared with RCD-fed WT controls. In WT mice under HFHCD, Light deficiency improved glucose tolerance and insulin sensitivity. Non-alcoholic fatty liver disease activity (NAS) score, hepatic CD3+ T lymphocytes and F4/80+ macrophages were decreased in HFHCD-fed Light-/- mice compared with HFHCD-fed WT controls. Consistent with a potential role of adipose tissue in hepatic homeostasis, Light-/- mice exhibited augmented anti-inflammatory F4/80+CD206+ adipose tissue macrophages and reduced proinflammatory F4/80+CD11c+ adipose tissue macrophages. Moreover, adipose tissue explants from Light-/- mice showed diminished secretion of monocyte chemoattractant protein 1 (MCP1), TNF-α and IL-17 cytokines. Circulating Light-/- leucocytes consistently displayed augmented levels of the patrolling Ly6Clow monocytes, decreased Th9 T cell subset and diminished plasma TNF-α and IL-6 levels. Similarly, Light deficiency in Irs2+/- mice, which display impaired insulin signalling, also reduced NAFL as well as systemic and adipose tissue inflammation. Analysis of hepatic gene expression in Light-/- mouse livers showed reduced levels of Zbtb16, the transcription factor essential for natural killer T (NKT) cell function, and two genes related to NAFLD and fibrosis, Klf6 and Tlr4. Conclusions/interpretation These results indicate that Light deficiency in HFHCD improves hepatic glucose tolerance, and reduces hepatic inflammation and NAFL. This is accompanied by decreased systemic inflammation and adipose tissue cytokine secretion and by changes in the expression of key genes such as Klf6 and Tlr4 involved in NAFLD. These results suggest that therapies to block LIGHT-dependent signalling might be useful to restore hepatic homeostasis and to restrain NAFLD.

Aging is associated with functional decline of hematopoietic stem cells (HSC) as well as an increased risk of myeloid malignancies. We performed an integrative characterization of epigenomic and transcriptomic changes, including single-cell RNA sequencing, during normal human aging. Lineage−CD34+CD38− cells [HSC-enriched (HSCe)] undergo age-associated epigenetic reprogramming consisting of redistribution of DNA methylation and reductions in H3K27ac, H3K4me1, and H3K4me3. This reprogramming of aged HSCe globally targets developmental and cancer pathways that are comparably altered in acute myeloid leukemia (AML) of all ages, encompassing loss of 4,646 active enhancers, 3,091 bivalent promoters, and deregulation of several epigenetic modifiers and key hematopoietic transcription factors, such as KLF6, BCL6, and RUNX3. Notably, in vitro downregulation of KLF6 results in impaired differentiation, increased colony-forming potential, and changes in expression that recapitulate aging and leukemia signatures. Thus, age-associated epigenetic reprogramming may form a predisposing condition for the development of age-related AML. Significance: AML, which is more frequent in the elderly, is characterized by epigenetic deregulation. We demonstrate that epigenetic reprogramming of human HSCs occurs with age, affecting cancer and developmental pathways. Downregulation of genes epigenetically altered with age leads to impairment in differentiation and partially recapitulates aging phenotypes. This article is highlighted in the In This Issue feature, p. 983

The elongation of very long chain fatty acids protein 6 (ELOVL6) gene encodes a key enzyme that plays a role in lipogenesis through the catalytic elongation of both saturated and monounsaturated fatty acids. Previous studies have described the high expression of bovine ELOVL6 in adipose tissues. However, transcriptional regulation and the functional role of ELOVL6 in lipid metabolism and adipocyte proliferation remain unexplored. Here, a 1.5 kb fragment of the 5'-untranslated region promoter region of ELOVL6 was amplified from the genomic DNA of Qinchuan cattle and sequenced. The core promoter region was identified through unidirectional 5'-end deletion of the promoter plasmid vector. In silico analysis predicted important transcription factors that were then validated through site-directed mutation and small interfering RNA interference with an electrophoretic mobility shift assay. We found that the binding of KLF6 and PU.1 transcription factors occurred in the region -168/+69. Both perform a vital regulatory function in the transcription of bovine ELOVL6. Overexpression of ELOVL6 significantly upregulated the expression of peroxisome proliferator activated receptor γ (PPARγ), but inhibited the expression of fatty acid-binding protein 4 (FABP4), while silencing of ELOVL6 negatively regulated the messenger RNA expression level of PPARγ, FABP4, ACSL, and FATP1. In addition, ELOVL6 promotes adipocyte proliferation by regulating the cell-cycle genes' expression. Taken together, these findings provide useful information about the transcriptional regulation and functional mechanisms of bovine ELOVL6 in lipid metabolism and adipocyte proliferation in Qinchuan cattle.

Altered cellular metabolism in kidney proximal tubule (PT) cells plays a critical role in acute kidney injury (AKI). The transcription factor Krüppel-like factor 6 (KLF6) is rapidly and robustly induced early in the PT after AKI. We found that PT-specific Klf6 knockdown (Klf6(PTKD)) is protective against AKI and kidney fibrosis in mice. Combined RNA and chromatin immunoprecipitation sequencing analysis demonstrated that expression of genes encoding branched-chain amino acid (BCAA) catabolic enzymes was preserved in Klf6(PTKD) mice, with KLF6 occupying the promoter region of these genes. Conversely, inducible KLF6 overexpression suppressed expression of BCAA genes and exacerbated kidney injury and fibrosis in mice. In vitro, injured cells overexpressing KLF6 had similar decreases in BCAA catabolic gene expression and were less able to utilize BCAA. Furthermore, knockdown of BCKDHB, which encodes one subunit of the rate-limiting enzyme in BCAA catabolism, resulted in reduced ATP production, while treatment with BCAA catabolism enhancer BT2 increased metabolism. Analysis of kidney function, KLF6, and BCAA gene expression in human chronic kidney disease patients showed significant inverse correlations between KLF6 and both kidney function and BCAA expression. Thus, targeting KLF6-mediated suppression of BCAA catabolism may serve as a key therapeutic target in AKI and kidney fibrosis.

Recent studies have investigated the ability of extracellular vesicles (EVs) in regulating neighboring cells by transferring signaling molecules, such as microRNAs (miRs) in renal fibrosis. EVs released by bone marrow mesenchymal stem cells (BMSCs) contain miR-181d, which may represent a potential therapy for renal fibrosis. miR-181d has been speculated to regulate Krüppel-like factor 6 (KLF6), which activates the nuclear factor-kappa B (NF-κB) signaling pathway. Luciferase assays were performed to confirm the relationship between miR-181d and KLF6. Gain- and loss-of-function studies in vivo and in vitro were performed to assess the effect of BMSC-derived EVs (BMSC-EVs), which contained miR-181d, on KLF6, NF-κB, and renal fibrosis. Transforming growth factor-β (TGF-β)-induced renal tubular epithelial HK-2 cells were treated with EVs derived from BMSCs followed by evaluation of collagen type IV α1 (Col4α1), Collagen I and α-smooth muscle actin (α-SMA) as indicators of the extent of renal fibrosis. Renal fibrosis was induced in rats by unilateral ureteral obstruction (UUO) followed by the subsequent analysis of fibrotic markers. BMSC-EVs had higher miR-181d expression. Overexpression of miR-181d correlated with a decrease in KLF6 expression as well as the levels of IκBα phosphorylation, α-SMA, Col4α1, TGF-βR1 and collagen I in HK-2 cells. In vivo, treatment with miR-181d-containing BMSC-derived EVs was able to restrict the progression of fibrosis in UUO-induced rats. Together, BMSC-EVs suppress fibrosis in vitro and in vivo by delivering miR-181d to neighboring cells, where it targets KLF6 and inhibits the NF-κB signaling pathway.

Krüppel-like factor 6 (KLF6) is one of the most studied members of the specificity protein/Krüppel-like factor (SP/KLF) transcription factor family. It has a typical zinc finger structure and plays a pivotal role in regulating the biological processes of cells. Recently, it has been considered to play a role in combatting cancer. Krüppel-like factor 6 splice variant 1 (KLF6-SV1), being one of the alternative KLF6 splicing isoforms, participates in tumor occurrence and development and has the potential to become a new target for molecular targeted therapy, although its action mechanism remains to be determined. The purpose of this article is to provide a comprehensive and systematic review of the important role of KLF6-SV1 in human malignant tumors to provide novel insights for oncotherapy.

Following the publication of this paper, it was drawn to the Editors' attention by a concerned reader that certain of the cell migration assay data shown in Fig. 2C were strikingly similar to data that had appeared in different form in other articles by different authors. Owing to the fact that the contentious data in the above article had already been published elsewhere, or were already under consideration for publication, prior to its submission to Molecular Medicine Reports , the Editor has decided that this paper should be retracted from the Journal. The authors were asked for an explanation to account for these concerns, but the Editorial Office did not receive a reply. The Editor apologizes to the readership for any inconvenience caused. [Molecular Medicine Reports 19: 1926‑1934, 2019; DOI: 10.3892/mmr.2019.9830].

MicroRNA-543-3p (miR-543-3p) has been reported to be involved in many human disease’s progression, but its role in inflammation is still unclear. After bacterial infection, innate immune cells are activated to trigger inflammation by recognizing lipopolysaccharide (LPS) on the bacterial outer membrane. In our research, it showed that miR-543-3p was down-regulated in LPS-treated periodontal ligament cells (PDLCs). And it mediated the apoptosis of PDLC induced by LPS, which may be involved in periodontitis development. Besides, up-regulation of miR-543-3p alleviated the inflammatory damage induced by LPS. Furthermore, our research demonstrated Kruppel-like factor 6 (KLF6) served as a direct downstream target of miR-543-3p to play a vital role in periodontitis. Simply put, these findings suggest that miR-543-3p could down-regulate inflammation and inhibit periodontitis by targeting KLF6, and it provides a new insight into the molecular mechanism of periodontitis, which may be helpful for the early diagnosis and treatment of this disease.

Circular RNAs (circRNAs) could regulate gene expression which may induce tumor occurrence and progression. In the current study, we first investigated the expression of circMTO1 in osteosarcoma, and the underlying mechanism was further elucidated.Circular RNA microarrays were used to identify the differential expression of circRNAs in osteosarcoma tissues and the corresponding normal tissues. qRT-PCR was used to examine the level of circMTO1 in osteosarcoma tissues and cell lines. In addition, circMTO1 overexpression was constructed using lentiviral transfection in cell lines. Subsequently, the Cell Counting Kit-8 (CCK8), cell migration and invasion, and flow cytometry were used to investigate the effect of circMTO1 on the biological functions of cells. The Western Blot and the recovery experiments were used to explore the potential mechanism.Here, we measured 20 circRNAs which were downregulated in osteosarcoma tissues using circRNA microarray. CircMTO1 expression was decreased in osteosarcoma cell lines. Besides, circMTO1 could inhibit cell proliferation, migration and invasion, and induced apoptosis in osteosarcoma cells. Bioinformatics analysis showed that circMTO1 serves as a sponge for miR-630 and KLF6 is a direct target of miR-630. Furthermore, circMTO1 functions through regulation of miR-630/KLF6 axis.Our study suggests circMTO1 could suppress osteosarcoma progression by regulating miR-630/KLF6 axis, which may highlight the diagnostic and therapeutic potential of these molecules in osteosarcoma treatment.

The heart is one of the target organs vulnerable to sepsis. About 50% of sepsis patients will suffer from myocardial injury and cardiac dysfunction, which will aggravate the sepsis and affect its prognosis. Here, we attempt to investigate the function of long non coding RNA PVT1 in LPS-induced cardiac fibroblasts in vitro, and explore its potential mechanism. The expression of PVT1 in LPS-induced cardiac fibroblasts was detected by qRT-PCR. CCK-8 assay, cell migration, qRT-PCR and western blotting analysis were applied to evaluating the effect of PVT1 knockdown on LPS-induced cardiac fibroblasts. The bioinformatics analysis and the rescue experiment were devoted to the underlying mechanism. PVT1 expression was up-regulated in LPS-induced cardiac fibroblasts. And knockdown of PVT1 inhibited cell viability and migration, alleviated inflammation cytokines production of LPS-treated cardiac fibroblasts. The bioinformatics analysis predicted PVT1 negatively regulates miR-24 and KLF6 is a direct target of miR-24. In a word, we observed PVT1 expression level was up-regulated in LPS- treated cardiac fibroblasts. PVT1 knockdown could alleviate LPS-induced biological behavior of cardiac fibroblasts through sponging miR-24 in vitro.

Oncogenic K-Ras (K-RasG12V) promotes senescence in normal cells but fuels transformation of cancer cells after the senescence barrier is bypassed. The mechanisms regulating this pleiotropic function of K-Ras remain to be fully established and bear high pathological significance. We find that K-RasG12V activates the angiotensinogen (AGT) gene promoter and promotes AGT protein expression in a Kruppel-like factor 6–dependent manner in normal cells. We show that AGT is then converted to angiotensin II (Ang II) in a cell-autonomous manner by cellular proteases. We show that blockade of the Ang II receptor type 1 (AT1-R) in normal cells inhibits oncogene-induced senescence. We provide evidence that the oncogenic K-Ras–induced synthesis of Ang II and AT1-R activation promote senescence through caveolin-1–dependent and nicotinamide adenine dinucleotide phosphate oxidase 2–mediated oxidative stress. Interestingly, we find that expression of AGT remains elevated in lung cancer cells but in a Kruppel-like factor 6–independent and high-mobility group AT-hook 1–dependent manner. We show that Ang II–mediated activation of the AT1-R promotes cell proliferation and anchorage-independent growth of lung cancer cells through a STAT3-dependent pathway. Finally, we find that expression of AGT is elevated in lung tumors of K-RasLA2-G12D mice, a mouse model of lung cancer, and human lung cancer. Treatment with the AT1-R antagonist losartan inhibits lung tumor formation in K-RasLA2-G12D mice. Together, our data provide evidence of the existence of a novel cell-autonomous and pleiotropic Ang II–dependent signaling pathway through which oncogenic K-Ras promotes oncogene-induced senescence in normal cells while fueling transformation in cancer cells.

Background. To further understand the development of the spinal cord, an exploration of the patterns and transcriptional features of spinal cord development in newborn mice at the cellular transcriptome level was carried out. Methods. The mouse single-cell sequencing (scRNA-seq) dataset was downloaded from the GSE108788 dataset. Single-cell RNA-Seq (scRNA-Seq) was conducted on cervical and lumbar spinal V2a interneurons from 2 P0 neonates. Single-cell analysis using the Seurat package was completed, and marker mRNAs were identified for each cluster. Then, pseudotemporal analysis was used to analyze the transcription changes of marker mRNAs in different clusters over time. Finally, the functions of these marker mRNAs were assessed by enrichment analysis and protein-protein interaction (PPI) networks. A transcriptional regulatory network was then constructed using the TRRUST dataset. Results. A total of 949 cells were screened. Single-cell analysis was conducted based on marker mRNAs of each cluster, which revealed the heterogeneity of neonatal mouse spinal cord neuronal cells. Functional analysis of pseudotemporal trajectory-related marker mRNAs suggested that pregnancy-specific glycoproteins (PSGs) and carcinoembryonic antigen cell adhesion molecules (CEACAMs) were the core mRNAs in cluster 3. GSVA analysis then demonstrated that the different clusters had differences in pathway activity. By constructing a transcriptional regulatory network, USF2 was identified to be a transcriptional regulator of CEACAM1 and CEACAM5, while KLF6 was identified to be a transcriptional regulator of PSG3 and PSG5. This conclusion was then validated using the Genotype-Tissue Expression (GTEx) spinal cord transcriptome dataset. Conclusions. This study completed an integrated analysis of a single-cell dataset with the utilization of marker mRNAs. USF2/CEACAM1&5 and KLF6/PSG3&5 transcriptional regulatory networks were identified by spinal cord single-cell analysis.

Background Considering the increase in the proportion of lung adenocarcinoma (LUAD) cases among all lung cancers and its considerable contribution to cancer‐related deaths worldwide, we sought to identify novel oncogenes to provide potential targets and facilitate a better understanding of the malignant progression of LUAD. Methods The results from the screening of transcriptome and survival analyses according to the integrated Gene Expression Omnibus (GEO) datasets and The Cancer Genome Atlas (TCGA) data were combined, and a promising risk biomarker called meiotic nuclear divisions 1 (MND1) was selectively acquired. Cell viability assays and subcutaneous xenograft models were used to validate the oncogenic role of MND1 in LUAD cell proliferation and tumor growth. A series of assays, including mass spectrometry, co‐immunoprecipitation (Co‐IP), and chromatin immunoprecipitation (ChIP), were performed to explore the underlying mechanism. Results MND1 up‐regulation was identified to be an independent risk factor for overall survival in LUAD patients evaluated by both tissue microarray staining and third party data analysis. In vivo and in vitro assays showed that MND1 promoted LUAD cell proliferation by regulating cell cycle. The results of the Co‐IP, ChIP and dual‐luciferase reporter assays validated that MND1 competitively bound to tumor suppressor Kruppel‐like factor 6 (KLF6), and thereby protecting E2F transcription factor 1 (E2F1) from KLF6‐induced transcriptional repression. Luciferase reporter and ChIP assays found that E2F1 activated MND1 transcription by binding to its promoter in a feedback manner. Conclusions MND1, KLF6, and E2F1 form a positive feedback loop to regulate cell cycle and confer DDP resistance in LUAD. MND1 is crucial for malignant progression and may be a potential therapeutic target in LUAD patients., In this study, a novel cell cycle regulator named meiotic nuclear divisions 1 (MND1) was firstly screened out as a potential oncogene in LUAD using different bioinformatic and statistical analyses. In mechanism, MND1 could directly bind to tumor suppressor kruppel‐like factor 6 (KLF6) to protect E2F1 from the transcriptional repression of KLF6. Interestingly, in return, E2F1 could activate MND1 transcription by binding to a specific site in the promoter region of MND1.

Background and purpose Atherosclerosis is a common cardiovascular disease with high morbidity and mortality. It is reported to be related to oscillatory shear stress (OSS)-induced endothelial dysfunction and excessive production of inflammatory factors. Azilsartan, a specific antagonist of the angiotensin II receptor, has been approved for the management of hypertensive subjects with diabetes mellitus type II (DMII). The present study will investigate the effects of azilsartan against OSS-induced endothelial dysfunction and inflammation, as well as the underlying mechanism. Materials and methods Cell viability was detected using an MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay. Quantitative reverse-transcription polymerase chain reaction (qRT-PCR) and enzyme-linked immunosorbent assay were used to determine the expression levels of IL-6, TNF-α, IL-1β, VCAM-1, and ICAM-1 in human aortic endothelial cells (HAECs). Generation of reactive oxygen species (ROS) was measured using 2'-7'dichlorofluorescin diacetate (DCFH-DA) staining, and the level of reduced glutathione (GSH) was evaluated using a commercial kit. The adhesion of THP-1 monocytes to HAECs was evaluated using calcein-AM staining. The expression level of KLF6 was determined using qRT-PCR and Western blot analysis. Results According to the result of the MTT assay, 5 and 10 μM azilsartan were considered as the optimized concentrations applied in the present study. The elevated production of IL-6, TNF-α, and IL-1β, increased levels of ROS, decreased levels of reduced GSH, upregulated VCAM-1, ICAM-1, and E-selectin, and the aggravated adhesion of THP-1 cells to HAECs induced by OSS were all reversed by the introduction of azilsartan. The downregulation of KLF6 induced by OSS was significantly reversed by azilsartan. By knocking down the expression of KLF6, the suppressed adhesion of THP-1 cells to the HAECs, and the downregulation of VCAM-1 and ICAM-1 induced by azilsartan in OSS-stimulated HAECs were greatly reversed. Conclusion The protective effects of azilsartan against OSS-induced endothelial dysfunction and inflammation might be mediated by KLF6.

Neutrophils display distinct gene expression patters depending on their developmental stage, activation state and tissue microenvironment. To determine the transcription factor networks that shape these responses in a mouse model, we integrated transcriptional and chromatin analyses of neutrophils during acute inflammation. We showed active chromatin remodeling at two transition stages: bone marrow-to-blood and blood-to-tissue. Analysis of differentially accessible regions revealed distinct sets of putative transcription factors associated with control of neutrophil inflammatory responses. Using ex vivo and in vivo approaches, we confirmed that RUNX1 and KLF6 modulate neutrophil maturation, whereas RELB, IRF5 and JUNB drive neutrophil effector responses and RFX2 and RELB promote survival. Interfering with neutrophil activation by targeting one of these factors, JUNB, reduced pathological inflammation in a mouse model of myocardial infarction. Therefore, our study represents a blueprint for transcriptional control of neutrophil responses in acute inflammation and opens possibilities for stage-specific therapeutic modulation of neutrophil function in disease.

Background Long non-coding RNAs (lncRNAs) are novel regulatory molecules in breast cancer development. LncRNA LUCAT1 is a potential tumor promoter in human cancers. In this study, we aimed to explore the role of LUCAT1 in human breast cancer tissues and cells. Methods A total of 31 breast cancer patients who underwent tumor resection, but without chemo- or radiotherapy or acute lung/heart/kidney diseases, provided tumor and adjacent normal tissues. Bioinformatic analysis, qRT-PCR, and luciferase reporter assay were carried out during the study. Results qRT-PCR analysis indicated that, compared with the adjacent tissues and MCF-10A normal breast epithelial cells, LUCAT1 was markedly up-regulated in the breast cancer tissues and five BC cell lines, including MDA-MB-231, MDA-MB-468, MDA-MB-435, SKBR3, and MCF-7. The knockdown of LUCAT1, through the transfection of small interfering RNA (siRNA) specific to LUCAT1, resulted in inhibition of proliferation in breast cancer cells. The expression levels of miR-181a-5p were decreased in the breast cancer tissues and five BC cell lines. Bioinformatic analysis and luciferase reporter assay suggested the interaction between miR-181a-5p and LUCAT1. In addition, the effects of LUCAT1 on promoting cell proliferation were attenuated by overexpression of miR-181a-5p through the transfection of miR-181a-5p mimic. Moreover, bioinformatics and luciferase reporter assay confirmed that miR-181a-5p targeted the 3′-UTR region of KLF6 and KLF15 mRNA, which were two tumor suppressor genes. LUCAT1/miR-181a-5p axis regulated the expression of KLF6 and KLF15 both in vitro and in vivo. Conclusions Our data indicate that LUCAT1/miR-181a-5p axis can serve as a novel therapeutic target in breast cancer.

Small nucleolar RNA host gene 6 (SNHG6) is a newly discovered long non-coding RNA (lncRNA), while the regulatory mechanism of SNHG6 in chondrosarcoma is largely unknown. Here we found that SNHG6 expression was upregulated and showed positive correlation with the progression of chondrosarcoma. Functional assays demonstrated that SNHG6 was required for the proliferation, migration, and invasion of chondrosarcoma cells. Mechanistic study revealed that SNHG6 could recruit EZH2 and maintain high level of H3K27me3 to repress the transcription of tumor-suppressor genes, including KLF6. KLF6 was found to bind to the promoter region of SP1 and restrained its transcription, while SP1 could be recruited to the promoter region of SNHG6 and promoted its transcription to form a positive loop. In summary, this study reveals that SP1-induced SNHG6 forms a positive loop to facilitate the carcinogenesis of chondrosarcoma through the suppression of KLF6 by recruiting EZH2, which manifests the oncogenic function of SNHG6 in chondrosarcoma.

Kruppel-like factors (KLFs) are a highly conserved family of transcription factors. We analysed expression profile data of KLFs and identified KLF6 as a new potential regulator of erythropoiesis. Knocking down the expression of KLF6 significantly raised γ-globin mRNA and protein levels in the erythroid cell line HUDEP-2 and haematopoietic progenitor (CD34+ ) cells. We found that overexpression of microRNA (miR)-2355-5p in HUDEP-2 and CD34+ cells correlated with increased γ-globin synthesis by suppressing expression of KLF6. Our discovery that the interaction between miR-2355-5p and KLF6 affects the expression of γ-globin may provide more information for the clinical management of β-thalassaemia patients.

Fibro/adipogenic progenitors (FAPs) are the main cellular source of fatty degeneration in muscle injury; however, the underlying mechanism of FAP adipogenesis in muscle degeneration needs to be further examined. Matrix metalloproteinase 14 (MMP-14) has been reported to induce the adipogenesis of 3T3-L1 preadipocytes, but whether MMP-14 also regulates the differentiation of FAPs remains unclear. To investigate whether and how MMP-14 regulates FAP adipogenesis and fatty infiltration in muscle degeneration, we examined MMP-14 expression in degenerative muscles and tested the effect of MMP-14 on FAP adipogenesis in vitro and in vivo. As expected, MMP-14 enhanced FAP adipogenesis and fatty infiltration in degenerative muscles; moreover, blocking endogenous MMP-14 in injured muscles facilitated muscle repair. Further investigations revealed that Kruppel-like factor 6 (KLF6) was a transcription factor associated with MMP-14 and acted as an "on-off" switch in the differentiation of FAPs into adipocytes or myofibroblasts. Moreover, KLF6 was the target gene of miR-22-3p, which was downregulated during FAP adipogenesis both in vitro and in vivo, and overexpression of miR-22-3p markedly prevented FAP adipogenesis and attenuated fatty degeneration in muscles. Our study revealed that miR-22-3p/KLF6/MMP-14 is a novel pathway in FAP adipogenesis and that inhibiting KLF6 is a potential strategy for the treatment of muscular degenerative diseases.

Psychiatric disorders are highly genetically correlated, and many studies have focused on their shared genetic components. However, little research has been conducted on the genetic differences between psychiatric disorders, because case-case comparisons of allele frequencies among cases currently require individual-level data from cases of both disorders. We developed a new method (CC-GWAS) to test for differences in allele frequency among cases of two different disorders using summary statistics from the respective case-control GWAS; CC-GWAS relies on analytical assessments of the genetic distance between cases and controls of each disorder. Simulations and analytical computations confirm that CC-GWAS is well-powered and attains effective control of type I error. In particular, CC-GWAS identifies and discards false positive associations that can arise due to differential tagging of a shared causal SNP (with the same allele frequency in cases of both disorders), e.g. due to subtle differences in ancestry between the input case-control studies. We applied CC-GWAS to publicly available summary statistics for schizophrenia, bipolar disorder and major depressive disorder, and identified 116 independent genome-wide significant loci distinguishing these three disorders, including 21 CC-GWAS-specific loci that were not genome-wide significant in the input case-control summary statistics. Two of the CC-GWAS-specific loci implicate the genes KLF6 and KLF16 from the Kruppel-like family of transcription factors; these genes have been linked to neurite outgrowth and axon regeneration. We performed a broader set of case-case comparisons by additionally analyzing ADHD, anorexia nervosa, autism, obsessive-compulsive disorder and Tourette’s Syndrome, yielding a total of 196 independent loci distinguishing eight psychiatric disorders, including 72 CC-GWAS-specific loci. We confirmed that loci identified by CC-GWAS replicated convincingly in applications to data sets for which independent replication data were available. In conclusion, CC-GWAS robustly identifies loci with different allele frequencies among cases of different disorders using results from the respective case-control GWAS, providing new insights into the genetic differences between eight psychiatric disorders.

The blood-spinal cord barrier (BSCB) is an effective, tightly-connected tissue that reduces secondary spinal cord injury (SCI) by decreasing blood cell infiltration, inflammation, and neuronal cell death during primary SCI. However, the methods and molecular mechanisms of BSCB openness remain elusive. In the present study, we found that microRNA429 (miR-429) plays a vital role in the opening of the blood-spinal cord. Inhibiting the expression of miR-429 (antagomiR-429) resulted in increased expression levels of the tight junction (TJ) proteins, ZO-1, occludin, and claudin-5, in the BSCB and reduced BSCB permeability. Moreover, overexpression of miR-429 (agomiR-429) had the opposite effect. Kruppel-like factor 6 (KLF6) is a transcription factor of the zinc-finger family. Using RT-qPCR and western blotting, we found that miR-429 can negatively regulate the expression of the KLF6. Co-transfection of KLF6 and miR-429 demonstrated that miR-429 negatively regulates KLF6 to mediate TJ protein expression and BSCB permeability. Based on these results, we suggest that KLF6 may be a downstream target of miR-429, mediating TJ protein expression to regulate the BSCB.

BACKGROUND Acute kidney injury (AKI) is one of the most important causes of death in sepsis patients. Here, we first measured the level of DANCR (differentiation antagonizing nonprotein coding RNA) expression in AKI, and the potential mechanism was further elucidated. MATERIAL AND METHODS We used qRT-PCR to examine the level of DANCR in patient blood serum samples and in HK-2 cells. In addition, DANCR overexpression was established using lentiviral transfection in HK-2 cells. Subsequently, Cell Counting Kit-8 (CCK-8) assay and flow cytometry were applied to evaluate the role of DANCR in HK-2 cells treated with lipopolysaccharide (LPS). Enzyme linked immunosorbent assay (ELISA), western blot and recovery experiments were performed to elucidate the further mechanism. RESULTS We found that DANCR was decreased in the serum of AKI patients and HK-2 cells treated with LPS. Additionally, DANCR promoted cell viability and suppressed cell apoptosis and cytokine production in LPS-treated HK-2 cells. Bioinformatics analysis showed that DANCR served as a sponge for miR-214. Furthermore, DANCR inhibited the expression of Krüppel-like factor 6 (KLF6). CONCLUSIONS Our study suggests that AKI development could be alleviated by sponging miR-214 and regulating KLF6 expression, which provides a novel potential mechanism involved in the diagnosis and treatment of sepsis-induced AKI patients.

Background: Dysregulation of polycomb chromobox (CBX) proteins that mediate epigenetic gene silencing contributes to the progression of human cancers. Yet their roles in clear cell renal cell carcinoma (ccRCC) remain to be explored. Methods: The expression of CBX4 and its clinical significance were determined by qRT-PCR, western blot, immunohistochemistry and statistical analyses. The biological function of CBX4 in ccRCC tumor growth and metastasis and the underlying mechanism were investigated using in vitro and in vivo models. Findings: CBX4 exerts oncogenic activities in ccRCC via interaction with HDAC1 to transcriptionally suppress tumor suppressor KLF6. CBX4 expression is increased in ccRCC and correlated with poor prognosis in two independent cohorts containing 840 patients. High CBX4 expression is significantly associated with Fuhrman grade and tumor lymph node invasion. CBX4 overexpression promotes tumor growth and metastasis, whereas CBX4 knockdown results in the opposite phenotypes. Mechanistically, CBX4 downregulates KLF6 via repressing the transcriptional activity of its promoter. Further studies show that CBX4 physically binds to HDAC1 to maintain its localization on the KLF6 promoter. Ectopic expression of KLF6 or disruption of CBX4-HDAC1 interaction attenuates CBX4-mediated cell growth and migration. Furthermore, CBX4 depletion markedly enhances the histone deacetylase inhibitor (HDACi)-induced cell apoptosis and suppression of tumor growth. Interpretation: Our data suggest CBX4 as an oncogene with prognostic potential in ccRCC. The newly identified CBX4/HDAC1/KLF6 axis may represent a potential therapeutic target for the clinical intervention of ccRCC. Keywords: CBX4, KLF6, HDAC1, Combinative therapy, Clear cell renal cell carcinoma

Ovarian cancer is one of the most ordinary fatal cancers. The role of long noncoding ribonucleic acids (lncRNAs) in tumor progression has caught the attention of numerous researchers. In this work, lncRNA LINP1 was studied to identify how it functioned in the progression of ovarian cancer.Firstly, quantitative real-time polymerase chain reaction (qRT-PCR) was utilized to measure LINP1 expression in ovarian cancer tissues. Furthermore, to identify the function of LINP1 in ovarian cancer, functional experiments were conducted. Also, by performing qRT-PCR and Western blot assay, the underlying mechanism was explored.In this research, LINP1 expression was remarkably higher in ovarian carcinoma samples compared with adjacent tissues. Moreover, cell proliferation, migration, and invasion were inhibited after LINP1 was silenced in the ovarian cancer cells. Besides, the messenger (mRNA) and the protein of KLF6 were overexpressed after LINP1 was silenced. Furthermore, the KLF6 expression level was negatively related to the LINP1 expression level in ovarian cancer samples.We discovered a potential oncogene in ovarian cancer and identified that LINP1 enhanced cell metastasis and proliferation via down-regulating KLF6.

Objectives In the pathogenesis of type 2 diabetes, development of insulin resistance triggers an increase in pancreatic β-cell insulin secretion capacity and β-cell number. Failure of this compensatory mechanism is caused by a dedifferentiation of β-cells, which leads to insufficient insulin secretion and diabetic hyperglycemia. The β-cell factors that normally protect against dedifferentiation remain poorly defined. Here, through a systems biology approach, we identify the transcription factor Klf6 as a regulator of β-cell adaptation to metabolic stress. Methods We used a β-cell specific Klf6 knockout mouse model to investigate whether Klf6 may be a potential regulator of β-cell adaptation to a metabolic stress. Results We show that inactivation of Klf6 in β-cells blunts their proliferation induced by the insulin resistance of pregnancy, high-fat high-sucrose feeding, and insulin receptor antagonism. Transcriptomic analysis showed that Klf6 controls the expression of β-cell proliferation genes and, in the presence of insulin resistance, it prevents the down-expression of genes controlling mature β-cell identity and the induction of disallowed genes that impair insulin secretion. Its expression also limits the transdifferentiation of β-cells into α-cells. Conclusion Our study identifies a new transcription factor that protects β-cells against dedifferentiation, and which may be targeted to prevent diabetes development., Highlights • Absence of Klf6 in β-cells leads to a reduction in their proliferation and mass during insulin resistance development. • Insulin receptor blockade by S961 leads to a greater dedifferentiation state in β-cell-specific Klf6 knockout mice. • Insulin receptor antagonism leads to enhanced β-cell to α-cell transdifferentiation in β-cell-specific Klf6 knockout mice.

Background & Aims: Primary sclerosing cholangitis (PSC) is characterized by chronic cholestasis and inflammation, which promotes cirrhosis and an increased risk of cholangiocellular carcinoma (CCA). The transcription factor Krueppel-like-factor-6 (KLF6) is a mediator of liver regeneration, steatosis, and hepatocellular carcinoma (HCC), but no data are yet available on its potential role in cholestasis. Here, we aimed to identify the impact of hepatic KLF6 expression on cholestatic liver injury and PSC and identify potential effects on farnesoid-X-receptor (FXR) signalling. Methods: Hepatocellular KLF6 expression was quantified by immunohistochemistry (IHC) in liver biopsies of PSC patients and correlated with serum parameters and clinical outcome. Liver injury was analysed in hepatocyte-specific Klf6-knockout mice following bile duct ligation (BDL). Chromatin-immunoprecipitation-assays (ChIP) and KLF6-overexpressing HepG2 cells were used to analyse the interaction of KLF6 and FXR target genes such as NR0B2. Results: Based on IHC, PSC patients could be subdivided into two groups showing either low (80%) hepatocellular KLF6 expression. In patients with high KLF6 expression, we observed a superior survival in Kaplan-Meier analysis. Klf6-knockout mice showed reduced hepatic necrosis following BDL when compared to controls. KLF6 suppressed NR0B2 expression in HepG2 cells mediated through binding of KLF6 to the NR0B2 promoter region. Conclusion: Here, we show an association between KLF6 expression and the clinical course and overall survival in PSC patients. Mechanistically, we identified a direct interaction of KLF6 with the FXR target gene NR0B2.

Tendinopathy is a common musculoskeletal disorder with characteristic hypervascularity. The mechanism of angiogenesis in tendinopathy remains unclear. The present study aimed to investigate the roles of miR-148a-3p in angiogenesis development of tendinopathy. In this study, we demonstrated that miR-148a-3p expression was increased in tendinopathy tissues and positively correlated with CD34 levels which is a specific marker for angiogenesis. We identified Krüppel-like factor 6 (KLF6) as a direct target gene of miR-148a-3p in tenocytes. Furthermore, reduced levels of KLF6 in tendinopathy tissues was showed using qRT-PCR and immunohistochemical analysis, compared with controls. A negative correlation between the levels of KLF6 mRNA and miR-148a-3p was observed. Then, we verified that miR-148a-3p could regulate Tsp-4 expression by targeting KLF6 in tenocyte and was positively correlated with Tsp-4 levels in tendinopathy tissues. In a coculture system of tenocytes with endothelial cells (ECs), we observed that transfection of Lv-miR-148a-3p markedly upregulated EC angiogenesis. In summary, our data establish a novel molecular mechanism by which miR-148a-3p upregulates Tsp-4 expression in tenocytes to promote EC angiogenesis by targeting KLF6, which could be helpful for the treatment of tendinopathy in the future.

Purpose. The transcription factor Krüppel-like factor 6 (KLF6) regulates various cellular functions, such as metabolism, cell proliferation, and differentiation. KLF6 plays a key role in the development and progression of multiple human cancers. Methods. Fifty primary biopsies and 10 normal nasopharyngeal mucosae were used to analyze by RT-QPCR the expression and the copy number of wtKLF6 and the spliced variants (KLF6-SV1, KLF6-SV2, and KLF6-SV3) in Tunisian patients with nasopharyngeal carcinoma. The expression analysis of E-cadherin and cyclin D1 was conducted by RT-QPCR and Western blot, respectively. Results. The wtKLF6 was significantly downexpressed in tumors compared to normal tissues (p=0.0015), whereas KLF6-SV1 and KLF6-SV2 were overexpressed in tumors compared to wtKLF6 and KLF6-SV3 (p<0.0001). Copy number variation was reduced in tumors compared to normal tissues (p=0.0071). Interestingly, KLF6-SV1 is associated with the juvenile form (p=0.0003) which is more aggressive than the adult form of NPC. Furthermore, the oncogenic variant KLF6-SV1 was overexpressed in tumors lacking the expression of E-cadherin (p=0.0022) suggesting its role in metastasis and tumor progression. The wtKLF6 is associated negatively with cyclin D1 in tumor tissues (p=0.048). Conclusion. The wtKLF6 was downexpressed in contrast with the oncogenic variants. Overexpression of KLF6-SV1 is associated with young patients, and loss of E-cadherin suggests that this variant correlated with the aggressiveness of NPC.

Background & Aims. Identifying NAFLD patients at risk of progression is crucial to orient medical care and resources. We aimed to verify if the effects determined by different single nucleotide polymorphisms (SNPs) could add up to multiply the risk of NAFLD and NASH-cirrhosis. Methods. Three study populations, that is, patients diagnosed with NASH-cirrhosis or with noncirrhotic NAFLD and healthy controls, were enrolled. PNPLA3 rs738409, TM6SF2 rs58542926, KLF6 rs3750861, SOD2 rs4880, and LPIN1 rs13412852 were genotyped. Results. One hundred and seven NASH-cirrhotics, 93 noncirrhotic NAFLD, and 90 controls were enrolled. At least one difference in allele frequency between groups was significant, or nearly significant, for the PNPLA3, TM6SF2, and KLF6 variants (p<0.001, p<0.05, and p=0.06, resp.), and a risk score based on these SNPs was generated. No differences were observed for SOD2 and LPIN1 SNPs. When compared to a score of 0, a score of 1-2 quadrupled, and a score of 3-4 increased 20-fold the risk of noncirrhotic NAFLD; a score of 3-4 quadrupled the risk of NASH-cirrhosis. Conclusions. The effects determined by disease-associated variants at different loci can add up to multiply the risk of NAFLD and NASH-cirrhosis. Combining different disease-associated variants may represent the way for genetics to keep strength in NAFLD diagnostics.

Supplemental Digital Content is available in the text., Kruppel like factor 6 (KLF6), a member of KLF family, which has classic zinc finger structure, is broadly considered to have anticancer activity. The role of SV2 variant, one of KLF6 alternative splicing isoforms has not yet been definite in the colorectal cancer. This study aimed to detect the expression of the KLF6-SV2 in colorectal cancer and investigate its impact on cell proliferation and apoptosis. qRT-PCR was used to quantitatively determine KLF6-SV2 mRNA expression in colorectal cancer samples, corresponding normal tissue, normal colonic mucosal cell line FHC and seven colorectal cancer cell lines. SW480 and SW620 cell models with over-expressing KLF6-SV2 were constructed. Cell proliferation, cell cycle and apoptosis were measured respectively using MTT assay, DNA ploidy detection and Annexin V flow cytometry. Meanwhile, expression of p53, p21 and Bax were detected by qRT-PCR and western blot. The mRNA expression level of KLF6-SV2 in colorectal cancer tissues (0.783±0.409) was decreased than in corresponding normal tissues (1.086±0.449) (P

Krüppel-like factor 6 (KLF6) is a transcription factor and tumor suppressor. We previously identified KLF6 as mediator of hepatocyte glucose and lipid homeostasis. The loss or reduction of KLF6 is linked to the progression of hepatocellular carcinoma, but its contribution to liver regeneration and repair in acute liver injury are lacking so far. Here we explore the role of KLF6 in acute liver injury models in mice, and in patients with acute liver failure (ALF). KLF6 was induced in hepatocytes in ALF, and in both acetaminophen (APAP)- and carbon tetrachloride (CCl4)-treated mice. In mice with hepatocyte-specific Klf6 knockout (DeltaKlf6), cell proliferation following partial hepatectomy (PHx) was increased compared to controls. Interestingly, key autophagic markers and mediators LC3-II, Atg7 and Beclin1 were reduced in DeltaKlf6 mice livers. Using luciferase assay and ChIP, KLF6 was established as a direct transcriptional activator of ATG7 and BECLIN1, but was dependent on the presence of p53. Here we show, that KLF6 expression is induced in ALF and in the regenerating liver, where it activates autophagy by transcriptional induction of ATG7 and BECLIN1 in a p53-dependent manner. These findings couple the activity of an important growth inhibitor in liver to the induction of autophagy in hepatocytes.

// Ao-Di He 1, * , Shao-Ping Wang 2, * , Wen Xie 1 , Wei Song 1 , Shuo Miao 1 , Ru-Ping Yang 1 , Ying Zhu 1 , Ji-Zhou Xiang 1 and Zhang-Yin Ming 1, 3 1 Department of Pharmacology, School of Basic Medicine, Tongji Medical College of Huazhong University of Science & Technology, Wuhan 430030, China 2 Department of Hepatobiliary Surgery, Affiliated Futian Hospital of Guangdong Medical College, Shenzhen 518033, China 3 The Key Laboratory for Drug Target Researches and Pharmacodynamic Evaluation of Hubei Province, Wuhan 430030, China * These authors have contributed equally to this work and are designated as co-first authors Correspondence to: Zhang-Yin Ming, email: zyming@hust.edu.cn Keywords: platelet, platelet releasate, HeLa cervical carcinoma cells, Kruppel-like factor 6, transforming growth factor beta Abbreviations: CRP, collagen-related peptide; KLF6, Kruppel-like factor 6; MTT, 3-(4, 5-dimethylthiazol)-2, 5-diphenyltetrazolium bromide; siRNA, small interfering RNA; TGF-β, transforming growth factor beta Received: April 25, 2017 Accepted: July 12, 2017 Published: August 03, 2017 ABSTRACT Platelets in the primary tumor microenvironment play crucial roles in regulating tumor growth, metastasis, and angiogenesis, but the underlying mechanisms are unclear. Here, we show that platelet releasates exhibited a proliferative effect on HeLa cells, and this effect correlated with a reduction of KLF6 expression. After incubation with either washed human platelets or collagen-related peptide (CRP) activated platelet releasates, expression of KLF6 in the HeLa cervical tumor cell line was markedly reduced. However, no significant difference was observed between control HeLa cells and HeLa cells incubated with resuspended activated platelet pellet. Moreover, the platelets’ promoting effect on HeLa cell growth was significantly abolished in KLF6 silenced HeLa cells. In addition, blocking TGF-β signaling with SB431542, a TGF-β receptor inhibitor, also counteracted the effect of platelets on proliferation and KLF6 expression in HeLa cells. From these findings, we conclude that platelet derived TGF-β promotes proliferation of HeLa cells by decreasing the expression of KLF6. The discovery that KLF6 is a key target of platelet-derived TGF-β signaling in HeLa cells identifies a potential new therapeutic target for the prevention and treatment of cervical carcinoma.

Platelets in the primary tumor microenvironment play crucial roles in the regulation of tumor progression, but the mechanisms underlying are poorly understood. Here, we report that platelet releasates exerted a proliferative effect on hepatocellular carcinoma (HCC) cells both in vitro and in vivo. This effect depended on a reduction of KLF6 expression in HCC cells. After incubation with either platelets or platelet granule contents, SMMC.7721 and HepG2 cells exhibited significant increases in proliferation and decreases in apoptosis. However, no effect was observed when incubating cancer cells with resuspended activated platelet pellet which exhausted of releasates. Platelet releasates also increased the population of HCC cells in the S and G2/M phases of the cell cycle and reduced the cell population in the G0/G1 phase. Moreover, knocking down KLF6 expression significantly diminished the platelet-mediated enhancement of HCC growth. In addition, blocking TGF-β signaling with the TGF-β receptor inhibitor SB431542 counteracted the effect of platelets on KLF6 expression and proliferation of HCC cells. Based on these findings, we conclude that platelet releasates, especially TGF-β, promote the proliferation of SMMC.7721 and HepG2 cells by decreasing expression of KLF6. This discovery identifies a potential new therapeutic target for the prevention and treatment of hepatocellular carcinoma.

Background and objective Diabetic pulmonary fibrosis is a severe disease that increases mortality risk of diabetes. However, the molecular mechanisms leading to pulmonary fibrosis in diabetes are poorly understood. This study investigated the roles of epithelial-mesenchymal transition (EMT) and the associated molecular mechanisms in streptozotocin (STZ)-induced rat pulmonary fibrosis. Methods The rat model of diabetic pulmonary fibrosis was established by intraperitoneal injection of a single dose of STZ (35 mg/kg). Typical lesions of diabetic pulmonary fibrosis were observed 8 weeks after STZ injection by hematoxylin-eosin (HE) and Masson staining. Human bronchial epithelial cells (HBECs) and A549 cells were treated by high glucose. Gene or protein expression was measured by real-time PCR, Western blot, immunohistochemistry or immunofluorescence. The knockdown of lectin-like oxidized low density lipoprotein receptor-1 (LOX-1) or transforming growth factor-β1 (TGF-β1) was conducted by siRNA. Results Activation of EMT was observed in lung tissues of STZ-induced diabetic rats, exhibiting a loss in the epithelial cell marker E-cadherin and an increase in the mesenchymal marker Vimentin. The protein and mRNA levels of LOX-1, TGF-β1 and kruppel-like factor 6 (KLF6) in the lung tissues were increased. Incubation of HBECs and A549 cells with high glucose activated EMT and induced an increase in LOX-1, TGF-β1 and KLF-6 expression. LOX-1 siRNA inhibited high glucose-induced EMT in HBECs and A549 cells, which correlated with the reduction of TGF-β1. TGF-β1 siRNA decreased the expression of LOX-1 and KLF6. Conclusions EMT was involved in the pathological process of diabetic pulmonary fibrosis, which was activated by LOX-1/TGF-β1/KLF6 signaling pathway.