Liraglutide Regulates the Kidney and Liver in Diabetic Nephropathy Rats through the miR-34a/SIRT1 Pathway

The role of SIRT1 in kidney diseases

SIRT1, a nicotinamide adenine dinucleotide (NAD +)-dependent class III histone deacetylase, exhibits a high level of expression within renal tissues. It has garnered considerable recognition for its pivotal role in modulating signaling pathways intricately linked with the aging process; however, it extends beyond this in the organism. The literature reports that SIRT1 regulates biological processes such as glucose metabolism, lipid metabolism, oxidative stress, inflammation, autophagy, endoplasmic reticulum stress, and apoptosis. Therefore, our study reviews the primary mechanisms by which SIRT1 induces kidney disease and the regulation of related signaling pathways in different models of renal disease. We also discuss commonly studied SIRT1-targeted interventional drugs reported in the literature, including inhibitors (e.g., Ex-527) and activators (e.g., resveratrol). This study aims to provide theoretical foundations and clinical insights for the development and screening of clinical drugs targeting SIRT1, aiming at enhanced scientific approaches for the prevention and treatment of kidney diseases.

MicroRNA193a: An Emerging Mediator of Glomerular Diseases

MicroRNAs (miRNAs) are noncoding small RNAs that regulate the protein expression of coding messenger RNAs. They are used as biomarkers to aid in diagnosing, prognosticating, and surveillance of diseases, especially solid cancers. MiR-193a was shown to be directly pathogenic in an experimental mouse model of focal segmental glomerulosclerosis (FSGS) during the last decade. Its specific binding and downregulation of Wilm's tumor-1 (WT-1), a transcription factor regulating podocyte phenotype, is documented. Also, miR-193a is a regulator switch causing the transdifferentiation of glomerular parietal epithelial cells to a podocyte phenotype in in vitro study. Interaction between miR-193a and apolipoprotein 1 (APOL1) mRNA in glomeruli (filtration units of kidneys) is potentially involved in the pathogenesis of common glomerular diseases. Since the last decade, there has been an increasing interest in the role of miR-193a in glomerular diseases, including diabetic nephropathy and membranous nephropathy, besides FSGS. Considering the lack of biomarkers to manage FSGS and diabetic nephropathy clinically, it is worthwhile to invest in evaluating miR-193a in the pathogenesis of these diseases. What causes the upregulation of miR-193a in FSGS and how the mechanism is different in different glomerular disorders still need to be elucidated. This narrative review highlights the pathogenic mechanisms of miR-193a elevation in various glomerular diseases and its potential use in clinical management.

Identification of Fibrotic Biomarkers Associated with Macrophages in Diabetic Nephropathy

BACKGROUND Diabetic nephropathy (DN) is the main cause of end-stage renal disease. Renal fibrosis is an important pathological feature of kidney injury, and the therapeutic means are very limited. The functions of macrophages play important roles in renal fibrosis. There is a complicated link between altered immune metabolism and oxidative stress. Hence, we designed this study to identify the oxidative stress- and macrophage-relevant biomarkers reflecting fibrosis in DN. MATERIAL AND METHODS Differential expression analysis was performed based on the GSE96804 dataset. xCell and weighted gene co-expression network analysis were used to determine the distinctions in infiltrating immune cells between DN and control specimens. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses were conducted. A protein-protein interaction network was constructed to identify the hub genes. Hub genes were validated in an external dataset, GSE30528, and cell models. RESULTS MMP2, CASP3, and HIF-1alpha were identified as biomarkers, which were upregulated in the DN group and positively correlated with the infiltration of macrophages and M1 macrophages. In vitro, the 3 genes were highly expressed in murine MPC5 cells treated with high glucose and human THP-1 macrophages treated with advanced glycation end products. CONCLUSIONS Our results provided biomarkers for predicting the fibrotic progression of DN and confirmed that MMP2, CAPS3, and HIF-1alpha have good diagnostic value. They might be involved in the progression of DN fibrosis by regulating oxidative stress and macrophage recruitment or polarization.

Interaction between SIRT1 and non-coding RNAs in different disorders

SIRT1 is a member of the sirtuin family functioning in the process of removal of acetyl groups from different proteins. This protein has several biological functions and is involved in the pathogenesis of metabolic diseases, malignancy, aging, neurodegenerative disorders and inflammation. Several long non-coding RNAs (lncRNAs), microRNAs (miRNAs) and circular RNAs (circRNAs) have been found to interact with SIRT1. These interactions have been assessed in the contexts of sepsis, cardiomyopathy, heart failure, non-alcoholic fatty liver disease, chronic hepatitis, cardiac fibrosis, myocardial ischemia/reperfusion injury, diabetes, ischemic stroke, immune-related disorders and cancers. Notably, SIRT1-interacting non-coding RNAs have been found to interact with each other. Several circRNA/miRNA and lncRNA/miRNA pairs that interact with SIRT1 have been identified. These axes are potential targets for design of novel therapies for different disorders. In the current review, we summarize the interactions between three classes of non-coding RNAs and SIRT1.

Liraglutide inhibits AngII-induced cardiac fibroblast proliferation and ECM deposition through regulating miR-21/PTEN/PI3K pathway

BACKGROUND

Cardiac fibrosis characterized with the aberrant proliferation of cardiac fibroblasts and extracellular matrix (ECM) deposition is a major pathophysiological feature of atrial fibrillation (AF). Liraglutide has exerted an alleviative role in various cardiovascular diseases, and can also regulate the level of microRNAs (miRNAs). It has been reported that miR-21 modulated cardiac fibrosis in AF. However, the regulative effect of liraglutide on atrial fibrosis via miR-21 and the underlying mechanism are still unclear.

METHODS

The atrial fibroblasts were isolated from the heart of C57BL/6 mice, and treated with Angiotensin II (AngII) and liraglutide. The proliferation, migration, and ECM deposition were determined by cell counting Kit-8 (CCK-8), Brdu, transwell assay, cell scratch, reverse transcription-quantitative polymerase chain reaction (RT-qPCR), western blot and immunofluorescence. The underlying mechanism was explored after transfection of miR-21 mimics into cells.

RESULTS

Liraglutide inhibited proliferation, migration, invasion of fibroblast cell and ECM deposition in AngII-stimulated cardiac fibroblasts. Additionally, liraglutide decreased the AngII-induced increase in the expression level of miR-21, but enhanced the expression of phosphatase and tensin homolog (PTEN), a target of miR-21, thereby suppressing the phosphoinositide 3-kinase (PI3K)/AKT signaling pathway. Rescue assay confirmed that overexpression of miR-21 counteracted the ameliorative effect of liraglutide on the proliferation, migration, invasion and ECM deposition in fibroblasts stimulated by AngII.

CONCLUSIONS

Liraglutide dampened AngII-induced proliferation and migration, and ECM deposition of cardiac fibroblast via modulating miR-21/PTEN/PI3K pathway.

Clinical efficacy and safety of warm acupuncture in the treatment of type 2 diabetic kidney disease: A protocol of a randomized controlled trial

BACKGROUND

Type 2 diabetic kidney disease (DKD) is one of the most common and harmful chronic complications in clinical practice, and there is no reliable and targeted treatment plan at present. As a classic complementary and alternative therapy, evidence have shown that warm acupuncture has advantages in the treatment of type 2 DKD. However, there is still a lack of high-quality and long-term follow-up randomized controlled trials of warm acupuncture in the treatment of type 2 DKD.

METHODS

This is a prospective randomized controlled trial to investigate the efficacy and safety of warm acupuncture in the treatment of type 2 DKD. Participants will be randomly assigned in a 1:1 ratio to either the treatment group (treated with conventional Western medicine) or the control group (treated with warm acupuncture added on the basis of the control group). Both groups will receive 12 weeks of treatment followed by 24 weeks of follow-up. Observation indicators include: 24-hour urinary protein quantification, kidney function, TCM syndrome score and adverse reactions. Finally, SPSS21.0 software will be used to analyze the data.

DISCUSSION

This study will evaluate the efficacy and safety of warm acupuncture in the treatment of DKD, and the results of this trial will provide clinical evidence for the treatment of type 2 DKD.

TRIAL REGISTRATION

The TCTR identification number is TCTR20221104004.

The Effect of Allograft Inflammatory Factor-1 on Inflammation, Oxidative Stress, and Autophagy via miR-34a/ATG4B Pathway in Diabetic Kidney Disease

Increasing evidence suggests that disorders of inflammation, oxidative stress, and autophagy contribute to the pathogenesis of diabetic kidney disease (DKD). This study attempted to clarify the effect of allograft inflammatory factor-1 (AIF-1), miR-34a, and ATG4B on inflammation, oxidative stress, and autophagy in DKD both in vitro and in vivo experiments. In vivo, it was found that the levels of AIF-1, miR-34a, oxidative stress, and inflammatory factors were significantly increased in blood and urine samples of DKD patients and mouse models and correlated with the level of urinary protein. In vitro, it was also found that the expressions of AIF-1, miR-34a, ROS, and inflammatory factors were increased, while ATG4B and other autophagy related proteins were decreased in human renal glomerular endothelial cells (HRGECs) cultured with high concentration glucose medium (30 mmol/L). When AIF-1 gene was overexpressed, the levels of miR-34a, ROS, and inflammatory factors were significantly upregulated, and autophagy-related proteins such as ATG4B were downregulated, while downregulation of AIF-1 gene had the opposite effect. In addition, miR-34a inhibited the expression of ATG4B and autophagy-related proteins and increased the levels of ROS and inflammation. Furthermore, the result of luciferase reporter assay suggested that ATG4B was the target gene of miR-34a. When ATG4B gene was overexpressed, the level of autophagy was upregulated, and inflammatory factors were downregulated. Conversely, when ATG4B gene was inhibited, the level of autophagy was downregulated, and inflammatory factors were upregulated. Then, autophagy inducers inhibited the levels of inflammation and ROS, whereas autophagy inhibitors had the opposite function in HRGECs induced by glucose (30 mmol/L). In conclusion, the above data suggested that AIF-1 regulated the levels of inflammation, oxidative stress, and autophagy in HRGECs via miR-34a/ATG4B pathway to contribute to the pathogenesis of diabetic kidney disease.

Dapagliflozin, Liraglutide, and Their Combination Attenuate Diabetes Mellitus-Associated Hepato-Renal Injury—Insight into Oxidative Injury/Inflammation/Apoptosis Modulation

In this study, we aim to explore the beneficial therapeutic impacts of dapagliflozin (Dapa), a highly potent, reversible, and selective sodium–glucose cotransporter-2 inhibitor, and liraglutide (Lira), a glucagon-like peptide-1 (GLP-1) receptor agonist, as hypoglycaemic agents for the management of diabetes mellitus (DM), as well as their combination against DM-induced complications, including hepato-renal injury. Indeed, the progression of DM was found to be associated with significant hepatic and renal injury, as confirmed by the elevated biochemical indices of hepatic and renal functions, as well as histopathological examination. Dapa, Lira, and their combination effectively attenuated DM-induced hepatic and renal injury, as confirmed by the recovery of hepatic and renal functional biomarkers. The administration of both drugs significantly reduced the tissue contents of MDA and restored the contents of GSH and catalase activity. Moreover, NF-κB and TNF-α expression at the protein and gene levels was significantly reduced in the liver and the kidney. This was in parallel with the significant reduction in the caspase-3 content in the liver and the kidney, as well as suppressed cleaved caspase-3 expression in the hepatic and renal specimens, as confirmed by immune–histochemical analysis. Notably, the combined Dapa/Lira treatment demonstrated an additive superior hepato-renal protective impact compared with the use of either drug alone. Thus, it appears that Dapa and Lira, through the coordinated modulation of oxidative, inflammatory, and apoptotic signalling, confer a significant hepato-renal protective impact against DM-induced complications and tissue injury.

Renoprotective Effect of Liraglutide Is Mediated via the Inhibition of TGF-Beta 1 in an LLC-PK1 Cell Model of Diabetic Nephropathy

Background: Recently published research demonstrated direct renoprotective effects of the glucagon-like peptide-1 receptor agonist GLP 1 RA, but the relevant molecular mechanisms are still not clear. The aim of this research was to assess the effects of Liraglutide in a cell culture model of diabetic nephropathy on cell viability, antioxidant (GSH) and transforming growth factor beta 1 (TGF- β1) levels and extracellular matrix (ECM) expression. The metabolic activity in hyperglycemic conditions and the effect of Liraglutide treatment were assessed by measuring Akt, pAkt, GSK3β, pGSK3β, pSTAT3, SOCS3, iNOS and NOX4 protein expression with Western blot. F actin distribution was used to assess the structural changes of the cells upon treatment. Materials and methods: The cells were exposed to high glucose (HG30 mM) followed by 0.5 mM H2O2 and a combination of glucose and H2O2 during 24 h. Subsequently, the cells were treated with different combinations of HG30, H2O2 and Liraglutide. Cell viability was determined by an MTT colorimetric test, and the GSH, TGF-β1 concentration and ECM expression were measured using a spectrophotometric/microplate reader assay and an ELISA kit, respectively. Western blotting was used to detect the protein level of Akt, pAkt, GSK3β, pGSK3β, pSTAT3, SOCS3, iNOS and NOX4. The F-actin cytoskeleton was visualized with Phalloidin stain and subsequently quantified. Results: Cell viability was decreased as well as GSH levels in cells treated with a combination of HG30/H2O2, and HG30 alone (p < 0.001). The addition of Liraglutide improved the viability in cells treated with HG30, but it did not affect the cell viability in the cell treated with the addition of H2O2. GSH increased with the addition of Liraglutide in HG30/H2O2 (p < 0.001) treated cells, with no effect in cells treated only with HG30. TGF-β1 levels (p < 0.001) were significantly increased in HG30 and HG30/H2O2. The addition of Liraglutide significantly decreased the TGF-β1 levels (p < 0.01; p < 0.05) in all treated cells. The synthesis of collagen was significantly increased in HG30/H2O2 (p < 0.001), while the addition of Liraglutide in HG30/H2O2 significantly decreased collagen (p < 0.001). Akt signaling was not significantly affected by treatment. The GSK3b and NOX4 levels were significantly reduced (p < 0.01) after the peroxide and glucose treatment, with the observable restoration upon the addition of Liraglutide suggesting an important role of Liraglutide in oxidative status regulation and mitochondrial activity. The treatment with Liraglutide significantly upregulated STAT3 (p < 0.01) activity, with no change in SOCS3 indicating a selective regulation of the STAT 3 signaling pathway in glucose and the oxidative overloaded environment. A significant reduction in the distribution of F-actin was observed in cells treated with HG30/H2O2 (p < 0.01). The addition of Liraglutide to HG30-treated cells led to a significant decrease of distribution of F-actin (p < 0.001). Conclusion: The protective effect of Liraglutide is mediated through the inhibition of TGF beta, but this effect is dependent on the extent of cellular damage and the type of toxic environment. Based on the WB analysis we have revealed the signaling pathways involved in cytoprotective and cytotoxic effects of the drug itself, and further molecular studies in vitro and vivo are required to elucidate the complexity of the pathophysiological mechanisms of Liraglutide under conditions of hyperglycemia and oxidative stress.