Early growth response factor 1 upregulates pro-fibrotic genes through activation of TGF-β1/Smad pathway via transcriptional regulation of PAR1 in high-glucose treated HK-2 cells

The Expression of miR-377-3p in Patients with DKD and the Regulatory Mechanism of miR-377-3p on the Inflammatory Response of HK-2 Cells Through TGF-β

Objective

The purpose of the study was to investigate the expression levels and correlation of inflammatory factors such as miR-377-3p and TGF-β in patients with diabetic kidney disease (DKD), and to investigate the regulatory mechanism of transfection of miR-377-3p on the inflammatory response of HK-2 cell induced by high glucose.

Methods

According to UACR, patients were divided into normal albuminuria group (Con, n = 29), microalbuminuria group (Micro, n = 31) and macroalbuminuria group (Macro, n = 30), analyzed the correlation and influencing factors between DKD and inflammatory factor. HK-2 cells were randomly divided into four groups: normal control group (NC), high glucose group (HG), miR-377-3p overexpression group (MIN), and miR-377-3p inhibition group (IN). After transfection of miR-377-3p mimics and inhibitors, the contents of TGF-β, IL-6 and IL-18 were detected by RT-PCR and Western blot.

Results

The levels of miR-377-3p, TGF-β, IL-6 and IL-18 in both Micro group and Macro group were significantly higher than those in Con group (P < 0.05); Pearson correlation analysis showed that miR-377-3p was positively correlated with UACR, TG, TGF-β, IL-6 and IL-18, and negatively correlated with GFR (P < 0.05). Cell experiment: RT-PCR and Western blot results showed that miR-377-3p, TGF-β, IL-6 and IL-18 in HG group were significantly higher than those in NC group (P < 0.05). After transfection with miR-377-3p inhibitor, the levels of miR-377-3p, TGF-β, IL-6 and IL-18 in IN group were significantly decreased compared with HG group and MIN group.

Conclusion

miR-377-3p expression was elevated both in serum of DKD patients and in HK-2 cells with high glucose induced injury, overexpression of miR-377-3p exacerbates the damage to HK-2 cells and promotes the progression of DKD. Silencing miR-377-3p can potentially regulate the levels of inflammatory factors in HK-2 cells by targeting downregulation of TGF-β expression, thereby mitigating the damage to HK-2 cells and delaying the development of diabetic kidney disease.

MicroRNA-204-5p Ameliorates Renal Injury via Regulating Keap1/Nrf2 Pathway in Diabetic Kidney Disease

Background

Diabetic kidney disease (DKD) is characterized by renal fibrosis, and the pathogenesis of renal fibrosis is still not definitely confirmed. MiR-204-5p plays an important role in the regulation of fibrosis, autophagy and oxidative stress. In this study, we aimed to investigate the role of miR-204-5p on renal damage in diabetic kidneys and the underlying mechanisms involved.

Methods

In vivo, AAV-Ksp-miR-204-5p mimics were injected into mice via tail vein. In vitro, high glucose-induced HK-2 cells were treated with miR-204-5p inhibitor, miR-204-5p mimics, ATG5 siRNA, tertiary butyl hydroquinone (TBHQ), ML385, or 3-Methyladenine (3-MA). FISH and qRT-PCR were used to detect miR-204-5p expression. The expressions of protein and mRNA were detected by Western blotting, immunofluorescence, immunohistochemistry and qRT-PCR. The concentration of fibronectin in HK-2 cells culture medium was detected by ELISA.

Results

The expression of miR-204-5p in diabetic kidneys was significantly inhibited than that in control group. Delivering miR-204-5p mimics increased miR-204-5p expression, improved renal function, inhibited renal fibrosis and oxidative stress, and restored autophagy in db/db mice. In vitro, the expression of miR-204-5p was inhibited by HG treatment in HK-2 cells. MiR-204-5p mimics effectively increased miR-204-5p expression and reduced fibronectin and collagen I expression, restored autophagy dysfunction, and increased Nrf2 expression, whereas these alterations were abrogated by Nrf2 inhibitor ML385, autophagy inhibitor 3-methyladenine (3-MA, 5 mM) treatment or ATG5 siRNA transfection in HG-induced HK-2 cells. In addition, miR-204-5p inhibitor significantly inhibited miR-204-5p expression and aggravated HG-induced fibronectin and collagen I expression, autophagy dysfunction, and decreased Nrf2 expression, while these alterations were abolished by Nrf2 activator TBHQ. Furthermore, the binding of miR-204-5p with Keap1 was confirmed by luciferase reporter assay and miR-204-5p negatively regulated Keap1 expression, resulting in the activation of Nrf2 pathway.

Conclusion

MicroRNA-204-5p protects against the progression of diabetic renal fibrosis by restoring autophagy via regulating Keap1/Nrf2 pathway.

Trigonelline inhibits tubular epithelial-mesenchymal transformation in diabetic kidney disease via targeting Smad7

OBJECTIVES

Diabetic kidney disease (DKD) is a prevalent microvascular complication of diabetes. Inhibiting the epithelial-mesenchymal transition (EMT) of proximal tubule epithelial cells (PTCs) can slow down renal fibrosis. Trigonelline (TRL), an alkaloid isolated from the fenugreek, has demonstrated therapeutic effects on diabetes and its complications. Nevertheless, the underlying mechanisms for the effects of TRL are still obscure. The present study was aimed to evaluate the treatment of TRL against DKD and explore the potential mechanisms.

METHODS

The db/db mice were used as a spontaneous model of DKD and TRL solution was administered by daily gavage for 8 weeks. Indicators associated with glucose metabolism, renal function and urinary albumin were tested. Renal fibrosis in diabetic mice was evaluated by histopathological staining. Kidney transcriptomics was performed after confirming therapeutic effects of TRL on DKD mice. Molecular biology techniques and in vitro experiments were utilized for final mechanism verification.

RESULTS

Biochemical tests revealed that TRL ameliorated renal damage and reduced microalbuminuria in DKD mice. TRL exhibited a protective effect on PTCs, effectively mitigating tubular EMT and renal fibrosis in diabetic kidneys. Transcriptomics analysis indicated that TRL may target Smad7, an inhibitor of TGF-β1 signaling, to alleviate fibrosis. Furthermore, in vitro experiments validated that silencing Smad7 abolished the therapeutic effect of TRL.

CONCLUSION

Our findings indicate that TRL can alleviate tubular epithelial-mesenchymal transition and renal fibrosis in db/db mice by upregulating Smad7 in PTCs, suggesting that TRL is a promising medicine against DKD.

To identify biomarkers associated with the transfer of diabetes combined with cancer in human genes using bioinformatics analysis

Currently, the incidence of diabetes mellitus is increasing rapidly, particularly in China, and its pathogenesis is still unclear. The goal of this study was to find meaningful biomarkers of metastasis in patients with diabetes and cancer using bioinformatic analysis in order to predict gene expression and prognostic importance for survival. We used the Differentially Expressed Gene, Database for Annotation Visualization and Integrated Discovery, and Gene Set Enrichment Analyses databases, as well as several bioinformatics tools, to explore the key genes in diabetes. Based on the above database, we ended up with 10 hub genes (FOS, ATF3, JUN, EGR1, FOSB, JUNB, BTG2, EGR2, ZFP36, and NR4A2). A discussion of the 10 critical genes, with extensive literature mentioned to validate the association between the 10 key genes and patients with diabetes and cancer, to demonstrate the importance of gene expression and survival prognosis. This study identifies several biomarkers associated with diabetes and cancer development and metastasis that may provide novel therapeutic targets for diabetes combined with cancer patients.

Lysophosphatidic Acid Induces Podocyte Pyroptosis in Diabetic Nephropathy by an Increase of Egr1 Expression via Downregulation of EzH2

Podocyte damage and renal inflammation are the main features and pathogenesis of diabetic nephropathy (DN). Inhibition of lysophosphatidic acid (LPA) receptor 1 (LPAR1) suppresses glomerular inflammation and improves DN. Herein, we investigated LPA-induced podocyte damage and its underlying mechanisms in DN. We investigated the effects of AM095, a specific LPAR1 inhibitor, on podocytes from streptozotocin (STZ)-induced diabetic mice. E11 cells were treated with LPA in the presence or absence of AM095, and the expression of NLRP3 inflammasome factors and pyroptosis were measured. A chromatin immunoprecipitation assay and Western blotting were performed to elucidate underlying molecular mechanisms. Gene knockdown by transfecting small interfering RNA was used to determine the role of the transcription factor Egr1 (early growth response protein 1) and histone methyltransferase EzH2 (Enhancer of Zeste Homolog 2) in LPA-induced podocyte injury. AM095 administration inhibited podocyte loss, NLRP3 inflammasome factor expression, and cell death in STZ-induced diabetic mice. In E11 cells, LPA increased NLRP3 inflammasome activation and pyroptosis via LPAR1. Egr1 mediated NLRP3 inflammasome activation and pyroptosis in LPA-treated E11 cells. LPA decreased H3K27me3 enrichment at the Egr1 promoter in E11 cells by downregulating EzH2 expression. EzH2 knockdown further increased LPA-induced Egr1 expression. In podocytes from STZ-induced diabetic mice, AM095 suppressed Egr1 expression increase and EzH2/H3K27me3 expression reduction. Collectively, these results demonstrate that LPA induces NLRP3 inflammasome activation by downregulating EzH2/H3K27me3 and upregulating Egr1 expression, resulting in podocyte damage and pyroptosis, which may be a potential mechanism of DN progression.