Long-chain non-coding RNA UCA1 inhibits renal tubular epithelial cell apoptosis by targeting microRNA-206 in diabetic nephropathy

Quercetin prevented diabetic nephropathy by inhibiting renal tubular epithelial cell apoptosis via the PI3K/AKT pathway

Diabetic nephropathy (DN) is the most common and serious complication of diabetes, posing a significant threat to human health. Currently, safe and effective preventive strategies for DN are lacking. The study aimed to explore the preventive effect and the underlying mechanism of quercetin against DN. In the in vivo experiments, we established a mouse model of type 2 diabetes mellitus (T2DM) induced by a combination of high-fat diet (HFD) and streptozotocin (STZ) to explore the preventive effect of quercetin on DN and its protective role against renal tubular epithelial cell apoptosis. Subsequently, in vitro experiments using human tubular epithelial cells (HK-2 cells) were conducted to further validate the protective effects of quercetin on renal tubular epithelial cell apoptosis. Additionally, we employed RNA sequencing analysis (RNA-seq) and network pharmacology analysis to comprehensively elucidate the molecular mechanisms involved. In vivo, we observed a significant increase in the ratio of urinary microalbumin to creatinine in diabetic mice compared to control mice, accompanied by the activation of renal tubular epithelial cell apoptosis. Remarkably, all of these changes were reversed after quercetin treatment. In vitro, high-glucose-induced apoptosis in HK-2 cells was significantly attenuated by quercetin. Subsequent RNA sequencing analysis and network pharmacology analysis revealed that quercetin was most likely to inhibit high-glucose-induced HK-2 cell apoptosis through the PI3K/AKT signaling pathway. Western Blotting results further demonstrated that quercetin could inhibit the activation of the PI3K/AKT signaling pathway in HK-2 cells induced by high glucose. Our results supported that quercetin could prevent DN by inhibiting tubular epithelial cell apoptosis via the PI3K/AKT pathway. Quercetin might be a promising candidate for the prevention of DN.

miRNA-206-3p alleviates LPS-induced acute lung injury via inhibiting inflammation and pyroptosis through modulating TLR4/NF-κB/NLRP3 pathway

Acute lung injury (ALI) is life-threatening. MicroRNAs (miRNAs) are often abnormally expressed in inflammatory diseases and are closely associated with ALI. This study investigates whether miRNA-206-3p attenuates pyroptosis in ALI and elucidates the underlying molecular mechanisms. ALI mouse and cell models were established through lipopolysaccharide (LPS) treatment for 24 h. Subsequently, the models were evaluated based on ultrasonography, the lung tissue wet/dry (W/D) ratio, pathological section assessment, electron microscopy, and western blotting. Pyroptosis in RAW264.7 cells was then assessed via electron microscopy, immunofluorescence, and western blotting. Additionally, the regulatory relationship between miRNA-206-3p and the Toll-like receptor (TLR)4/nuclear factor (NF)-κB/Nod-like receptor protein-3 (NLRP3) pathway was verified. Finally, luciferase reporter gene and RNA pull-down assays were used to verify the targeting relationship between miRNA-206-3p and TLR4. miRNA206-3p levels are significantly decreased in the LPS-induced ALI model. Overexpression of miRNA-206-3p improves ALI, manifested as improved lung ultrasound, improved pathological changes of lung tissue, reduced W/D ratio of lung tissue, release of inflammatory factors in lung tissue, and reduced pyroptosis. Furthermore, overexpression of miRNA-206-3p contributed to reversing the ALI-promoting effect of LPS by hindering TLR4, myeloid differentiation primary response 88 (MyD88), NF-κB, and NLRP3 expression. In fact, miRNA-206-3p binds directly to TLR4. In conclusion, miRNA-206-3p alleviates LPS-induced ALI by inhibiting inflammation and pyroptosis via TLR4/NF-κB/NLRP3 pathway modulation.

Diabetic nephropathy: Focusing on pathological signals, clinical treatment, and dietary regulation

Diabetic nephropathy (DN) is one of the most severe complications of diabetes. However, due to its complex pathological mechanisms, no effective therapeutic methods (other than ACEIs and ARBs) have been applied, which have been used for many years in clinical practice. Recent studies have shown that emerging therapeutics, including novel target-based pharmacotherapy, cell therapies, and dietary regulation, are leading to new hopes for DN management. This review aims to shed new light on the treatment of DN by describing the important pathological mechanisms of DN and by analysing recent advances in clinical treatment, including drug therapy, cell therapy, and dietary regulation. In pathological mechanisms, RAAS activation, AGE accumulation, and EMT are involved in inflammation, cellular stress, apoptosis, pyroptosis, and autophagy. In pharmacotherapy, several new therapeutics, including SGLT2 inhibitors, GLP-1 agonists, and MRAs, are receiving public attention. In addition, stem cell therapies and dietary regulation are also being emphasized. Herein, we highlight the importance of combining therapy and dietary regulation in the treatment of DN and anticipate more basic research or clinical trials to verify novel strategies.

lncRNA UCA1 inhibits mitochondrial dysfunction of skeletal muscle in type 2 diabetes mellitus by sequestering miR-143-3p to release FGF21

Increasing evidence suggests that insulin resistance in type 2 diabetes mellitus (T2DM) is associated with mitochondrial dysfunction in skeletal muscle, while the underlying molecular mechanisms remain elusive. This study aims to construct a ceRNA regulatory network that is involved in mitochondrial dysfunction of skeletal muscle in T2DM. Based on GEO database analysis, differentially expressed lncRNA and mRNA profiles were identified in skeletal muscle tissues of T2DM. Next, LASSO regression analysis was conducted to predict the key lncRNAs related to T2DM, which was validated by receiver operating characteristic (ROC) analysis. Moreover, the miRNAs related to skeletal muscle in T2DM were identified by WGCNA, followed by construction of gene-gene interaction network and GO and KEGG enrichment analyses. It was found that 12 lncRNAs and 6 miRNAs were related to skeletal muscle in T2DM. Moreover, the lncRNA-miRNA-mRNA ceRNA network involving UCA1, miR-143-3p, and FGF21 was constructed. UCA1, and FGF21 were downregulated, while miR-143-3p was upregulated in skeletal muscle cells (SkMCs) exposed to palmitic acid. Additionally, ectopic expression experiments were performed in SkMCs to confirm the effects of UCA1/miR-143-3p/FGF21 on mitochondrial dysfunction by determining mitochondrial ROS, oxygen consumption rate (OCR), membrane potential, and ATP level. Overexpression of miR-143-3p increased ROS accumulation and reduced the OCR, fluorescence ratio of JC-1, and ATP level, which were reversed by upregulation of UCA1 or FGF21. Collectively, lncRNA UCA1 inhibited mitochondrial dysfunction of skeletal muscle in T2DM by sequestering miR-143-3p away from FGF21, therefore providing a potential therapeutic target for alleviating mitochondrial dysfunction of skeletal muscle in T2DM.

Long Non-Coding RNAs in the Pathogenesis of Diabetic Kidney Disease

Diabetic kidney disease (DKD) is one of the major microvascular complications of diabetes mellitus, with relatively high morbidity and mortality globally but still in short therapeutic options. Over the decades, a large body of data has demonstrated that oxidative stress, inflammatory responses, and hemodynamic disorders might exert critical influence in the initiation and development of DKD, whereas the delicate pathogenesis of DKD remains profoundly elusive. Recently, long non-coding RNAs (lncRNAs), extensively studied in the field of cancer, are attracting increasing attentions on the development of diabetes mellitus and its complications including DKD, diabetic retinopathy, and diabetic cardiomyopathy. In this review, we chiefly focused on abnormal expression and function of lncRNAs in major resident cells (mesangial cell, endothelial cell, podocyte, and tubular epithelial cell) in the kidney, summarized the critical roles of lncRNAs in the pathogenesis of DKD, and elaborated their potential therapeutic significance, in order to advance our knowledge in this field, which might help in future research and clinical treatment for the disease.

Long non-coding ribonucleic acid urothelial carcinoma-associated 1 promotes high glucose-induced human retinal endothelial cells angiogenesis through regulating micro-ribonucleic acid-624-3p/vascular endothelial growth factor C

AIMS/INTRODUCTION

Emerging evidence has indicated that long non-coding ribonucleic acids play important roles in the development and progression of diabetic retinopathy (DR). It is reported that urothelial carcinoma-associated 1 (UCA1) is highly expressed in diabetic lymphoendothelial cells and influences glucose metabolism in rats with DR. The aim of the present study was to explore the role of UCA1 in the mechanism of DR.

MATERIALS AND METHODS

Gene expression analyses in fibrovascular membranes excised from patients with DR using public microarray datasets (GSE60436). Reverse transcription polymerase chain reaction was carried out to detect UCA1, micro-ribonucleic acid (miR)-624-3p and vascular endothelial growth factor C (VEGF-C) expressions in the blood of patients and human retinal endothelial cells (HRECs). Furthermore, Cell Counting kit-8, Transwell assay, and tube formation assay were used to identify biological effects of UCA1 on HRECs proliferation, migration ability and angiogenesis in vitro.

RESULTS

UCA1 and VEGF-C were elevated in DR patients and high glucose-induced HRECs cell lines, whereas miR-624-3p was decreased. UCA1 inhibition inhibited proliferation, angiogenesis and migration of HRECs cells under high-glucose condition. Luciferase reporter assay showed that UCA1 could sponge with miR-624-3p, which could directly target VEGF-C. Finally, we proved a pathway that UCA1 promoted cell proliferation, migration and angiogenesis through sponging with miR-624-3p, thereby upregulating VEGF-C in high-glucose-induced HRECs.

CONCLUSIONS

We identified UCA1 as an important factor associated with DR, which could regulate the expression of VEGF-C by sponging miR-624-3p in human retinal endothelial cells. Our results pave the way for further studies on diagnostic and therapeutic studies related to UCA1 in DR patients.

Epigenetics and Inflammation in Diabetic Nephropathy

Diabetic nephropathy (DN) leads to high morbidity and disability. Inflammation plays a critical role in the pathogenesis of DN, which involves renal cells and immune cells, the microenvironment, as well as extrinsic factors, such as hyperglycemia, chemokines, cytokines, and growth factors. Epigenetic modifications usually regulate gene expression via DNA methylation, histone modification, and non-coding RNAs without altering the DNA sequence. During the past years, numerous studies have been published to reveal the mechanisms of epigenetic modifications that regulate inflammation in DN. This review aimed to summarize the latest evidence on the interplay of epigenetics and inflammation in DN, and highlight the potential targets for treatment and diagnosis of DN.

Calcitriol attenuates renal tubular epithelial cells apoptosis via inhibiting p38MAPK signaling in diabetic nephropathy

AIMS

To observe the effect of calcitriol on tubular epithelial cells apoptosis in diabetic nephropathy (DN) and to explore the possible mechanism of its renal protection.

METHODS

In vivo, DN rats established by streptozocin (STZ) were treated with or without calcitriol by gavage. Rats were killed at 18 weeks after treatment. In vitro, HK-2 cells were cultured in high glucose with or without 1,25-dihydroxyvitamin D3. In some experiments, P38MAPK activator anisomycin was applied to incubate HK-2 cells. Cell apoptosis was detected by TUNEL or Annexin V-FITC/PI staining with flow cytometry. Immunohistochemical staining was used to observe the expression of VDR in kidney. Protein expression of cleaved caspase-3, Bax, Bcl-2, VDR, pp38MAPK and p38MAPK was assessed by western blotting.

RESULT

Calcitriol treatment ameliorated the severity of proteinuria and reduced renal tubular epithelial cells apoptosis in DN rats. In addition, calcitriol treatment significantly increased renal VDR expression and reduced the expression of p-p38MAPK in rats. In vitro, 1,25-dihydroxyvitamin D3 decreased the apoptotic rate of HK-2 cells induced by high glucose. In accord with the results from animal study, 1,25-dihydroxyvitamin D3 increased VDR expression, but decreased p-p38MAPK expression in HK-2 cells. Moreover, P38MAPK activator anisomycin blocked the anti-apoptotic effect of 1,25-dihydroxyvitamin D3 on HK-2 cells.

CONCLUSIONS

Calcitriol attenuates renal tubular cells apoptosis via VDR activation which inhibits p38MAPK signaling in DN rats.