MicroRNA: A new generation therapeutic target in diabetic nephropathy

Urinary biomarkers in diabetic nephropathy

Diabetic nephropathy (DN), a significant consequence of diabetes, is associated with adverse cardiovascular and renal disease as well as mortality. Although microalbuminuria is considered the best non-invasive marker for DN, better predictive markers are needed of sufficient sensitivity and specificity to detect disease in general and in early disease specifically. Even prior to appearance of microalbuminuria, urinary biomarkers increase in diabetics and can serve as accurate nephropathy biomarkers even in normoalbuminuria. In this review, a number of novel urine biomarkers including those reflecting kidney damage caused by glomerular/podocyte damage, tubular damage, oxidative stress, inflammation, and intrarenal renin-angiotensin system activation are discussed. Our review also includes emerging biomarkers such as urinary microRNAs. These short noncoding miRNAs regulate gene expression and could be utilized to identify potential novel biomarkers in DN development and progression. .

Identification of immune-associated biomarkers of diabetes nephropathy tubulointerstitial injury based on machine learning: a bioinformatics multi-chip integrated analysis

BACKGROUND

Diabetic nephropathy (DN) is a major microvascular complication of diabetes and has become the leading cause of end-stage renal disease worldwide. A considerable number of DN patients have experienced irreversible end-stage renal disease progression due to the inability to diagnose the disease early. Therefore, reliable biomarkers that are helpful for early diagnosis and treatment are identified. The migration of immune cells to the kidney is considered to be a key step in the progression of DN-related vascular injury. Therefore, finding markers in this process may be more helpful for the early diagnosis and progression prediction of DN.

METHODS

The gene chip data were retrieved from the GEO database using the search term ' diabetic nephropathy '. The ' limma ' software package was used to identify differentially expressed genes (DEGs) between DN and control samples. Gene set enrichment analysis (GSEA) was performed on genes obtained from the molecular characteristic database (MSigDB. The R package 'WGCNA' was used to identify gene modules associated with tubulointerstitial injury in DN, and it was crossed with immune-related DEGs to identify target genes. Gene ontology (GO) enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were performed on differentially expressed genes using the 'ClusterProfiler' software package in R. Three methods, least absolute shrinkage and selection operator (LASSO), support vector machine recursive feature elimination (SVM-RFE) and random forest (RF), were used to select immune-related biomarkers for diagnosis. We retrieved the tubulointerstitial dataset from the Nephroseq database to construct an external validation dataset. Unsupervised clustering analysis of the expression levels of immune-related biomarkers was performed using the 'ConsensusClusterPlus 'R software package. The urine of patients who visited Dongzhimen Hospital of Beijing University of Chinese Medicine from September 2021 to March 2023 was collected, and Elisa was used to detect the mRNA expression level of immune-related biomarkers in urine. Pearson correlation analysis was used to detect the effect of immune-related biomarker expression on renal function in DN patients.

RESULTS

Four microarray datasets from the GEO database are included in the analysis : GSE30122, GSE47185, GSE99340 and GSE104954. These datasets included 63 DN patients and 55 healthy controls. A total of 9415 genes were detected in the data set. We found 153 differentially expressed immune-related genes, of which 112 genes were up-regulated, 41 genes were down-regulated, and 119 overlapping genes were identified. GO analysis showed that they were involved in various biological processes including leukocyte-mediated immunity. KEGG analysis showed that these target genes were mainly involved in the formation of phagosomes in Staphylococcus aureus infection. Among these 119 overlapping genes, machine learning results identified AGR2, CCR2, CEBPD, CISH, CX3CR1, DEFB1 and FSTL1 as potential tubulointerstitial immune-related biomarkers. External validation suggested that the above markers showed diagnostic efficacy in distinguishing DN patients from healthy controls. Clinical studies have shown that the expression of AGR2, CX3CR1 and FSTL1 in urine samples of DN patients is negatively correlated with GFR, the expression of CX3CR1 and FSTL1 in urine samples of DN is positively correlated with serum creatinine, while the expression of DEFB1 in urine samples of DN is negatively correlated with serum creatinine. In addition, the expression of CX3CR1 in DN urine samples was positively correlated with proteinuria, while the expression of DEFB1 in DN urine samples was negatively correlated with proteinuria. Finally, according to the level of proteinuria, DN patients were divided into nephrotic proteinuria group (n = 24) and subrenal proteinuria group. There were significant differences in urinary AGR2, CCR2 and DEFB1 between the two groups by unpaired t test (P < 0.05).

CONCLUSIONS

Our study provides new insights into the role of immune-related biomarkers in DN tubulointerstitial injury and provides potential targets for early diagnosis and treatment of DN patients. Seven different genes ( AGR2, CCR2, CEBPD, CISH, CX3CR1, DEFB1, FSTL1 ), as promising sensitive biomarkers, may affect the progression of DN by regulating immune inflammatory response. However, further comprehensive studies are needed to fully understand their exact molecular mechanisms and functional pathways in DN.

Deciphering the role of MicroRNAs in diabetic nephropathy: Regulatory mechanisms and molecular insights

A serious consequence of diabetes mellitus, diabetic nephropathy (DN) which causes gradual damage to the kidneys. Dietary changes, blood pressure control, glucose control, and hyperlipidemia are all important components of DN management. New research, however, points to microRNAs (miRNAs) as having a pivotal role in DN pathogenesis. Miniature non-coding RNA molecules such as miRNAs control gene expression and impact several biological processes. The canonical and non-canonical routes of miRNA biogenesis are discussed in this article. In addition, several important signaling pathways are examined in the study of miRNA regulation in DN. A deeper knowledge of these regulatory mechanisms would allow for a better understanding of the molecular basis of DN and the development of innovative therapeutic strategies. Finally, miRNAs show tremendous potential as DN diagnostic biomarkers and treatment targets, opening up promising avenues for further study and potential clinical use.

N6-methyladenosine RNA methylation in diabetic kidney disease

Diabetic kidney disease (DKD) is a major microvascular complication of diabetes, and hyperglycemic memory associated with diabetes carries the risk of disease occurrence, even after the termination of blood glucose injury. The existence of hyperglycemic memory supports the concept of an epigenetic mechanism involving n6-methyladenosine (m6A) modification. Several studies have shown that m6A plays a key role in the pathogenesis of DKD. This review addresses the role and mechanism of m6A RNA modification in the progression of DKD, including the regulatory role of m6A modification in pathological processes, such as inflammation, oxidative stress, fibrosis, and non-coding (nc) RNA. This reveals the importance of m6A in the occurrence and development of DKD, suggesting that m6A may play a role in hyperglycemic memory phenomenon. This review also discusses how some gray areas, such as m6A modified multiple enzymes, interact to affect the development of DKD and provides countermeasures. In conclusion, this review enhances our understanding of DKD from the perspective of m6A modifications and provides new targets for future therapeutic strategies. In addition, the insights discussed here support the existence of hyperglycemic memory effects in DKD, which may have far-reaching implications for the development of novel treatments. We hypothesize that m6A RNA modification, as a key factor regulating the development of DKD, provides a new perspective for the in-depth exploration of DKD and provides a novel option for the clinical management of patients with DKD.

Tumor-derived small extracellular vesicles in cancer invasion and metastasis: molecular mechanisms, and clinical significance

The production and release of tumor-derived small extracellular vesicles (TDSEVs) from cancerous cells play a pivotal role in the propagation of cancer, through genetic and biological communication with healthy cells. TDSEVs are known to orchestrate the invasion-metastasis cascade via diverse pathways. Regulation of early metastasis processes, pre-metastatic niche formation, immune system regulation, angiogenesis initiation, extracellular matrix (ECM) remodeling, immune modulation, and epithelial-mesenchymal transition (EMT) are among the pathways regulated by TDSEVs. MicroRNAs (miRs) carried within TDSEVs play a pivotal role as a double-edged sword and can either promote metastasis or inhibit cancer progression. TDSEVs can serve as excellent markers for early detection of tumors, and tumor metastases. From a therapeutic point of view, the risk of cancer metastasis may be reduced by limiting the production of TDSEVs from tumor cells. On the other hand, TDSEVs represent a promising approach for in vivo delivery of therapeutic cargo to tumor cells. The present review article discusses the recent developments and the current views of TDSEVs in the field of cancer research and clinical applications.

Discussing pathologic mechanisms of Diabetic retinopathy & therapeutic potentials of curcumin and β-glucogallin in the management of Diabetic retinopathy

Diabetic retinopathy (DR) is a form of retinal microangiopathy that occurs as a result of long-term Diabetes mellitus (DM). Patients with Diabetes mellitus typically suffer from DR as a progression of the disease that may be due to initiation and dysregulation of pathways like the polyol, hexosamine, the AGE/RAGE, and the PKC pathway, which all have negative impacts on eye health and vision. In this review, various databases, including PubMed, Google Scholar, Web of Science, and Science Direct, were scoured for data relevant to the aforementioned title. The three most common therapies for DR today are retinal photocoagulation, anti-vascular endothelial growth factor (VEGF) therapy, and vitrectomy, however, there are a number of drawbacks and limits to these methods. So, it is of critical importance and profound interest to discover treatments that may successfully address the pathogenesis of DR. Curcumin and β-glucogallin are the two potent compounds of natural origin that are already being used in various nutraceutical formulations for several ailments. They have been shown potent antiapoptotic, anti-inflammatory, antioxidant, anticancer, and pro-vascular function benefits in animal experiments. Their parent plant species have been used for generations by practitioners of traditional herbal medicine for the treatment and prevention of various eye ailments. In this review, we will discuss about pathophysiology of Diabetic retinopathy and the therapeutic potentials of curcumin and β-glucogallin one of the principal compounds from Curcuma longa and Emblica officinalis in Diabetic retinopathy.

Circular RNAs: An emerging precise weapon for diabetic nephropathy diagnosis and therapy

Diabetic nephropathy (DN) is a prevalent chronic microvascular complication associated with diabetes mellitus and represents a major cause of chronic kidney disease and renal failure. Current treatment strategies for DN primarily focus on symptom alleviation, lacking effective approaches to halt or reverse DN progression. Circular RNA (circRNA), characterized by a closed-loop structure, has emerged as a novel non-coding RNA regulator of gene expression, attributed to its conservation, stability, specificity, and multifunctionality. Dysregulation of circRNA expression is closely associated with DN progression, whereby circRNA impacts kidney cell injury by modulating cell cycle, differentiation, cell death, as well as influencing the release of inflammatory factors and stromal fibronectin expression. Consequently, circRNA is considered a predictive biomarker and a potential therapeutic target for DN. This review provides an overview of the latest research progress in the classification, functions, monitoring methods, and databases related to circRNA. The paper focuses on elucidating the impact and underlying mechanisms of circRNA on kidney cells under diabetic conditions, aiming to offer novel insights into the prevention, diagnosis, and treatment of DN.

Nanomedicines for the management of diabetic nephropathy: present progress and prospects

Diabetic nephropathy (DN) is a serious microvascular consequence of diabetes mellitus (DM), posing an encumbrance to public health worldwide. Control over the onset and progress of DN depend heavily on early detection and effective treatment. DN is a major contributor to end-stage renal disease, and a complete cure is yet to be achieved with currently available options. Though some therapeutic molecules have exhibited promise in treating DN complications, their poor solubility profile, low bioavailability, poor permeation, high therapeutic dose and associated toxicity, and low patient compliance apprehend their clinical usefulness. Recent research has indicated nano-systems as potential theranostic platforms displaying futuristic promise in the diagnosis and treatment of DN. Early and accurate diagnosis, site-specific delivery and retention by virtue of ligand conjugation, and improved pharmacokinetic profile are amongst the major advantages of nano-platforms, defining their superiority. Thus, the emergence of nanoparticles has offered fresh approaches to the possible diagnostic and therapeutic strategies regarding DN. The present review corroborates an updated overview of different types of nanocarriers regarding potential approaches for the diagnosis and therapy of DN.

Hsa_circ_0003928 regulates the progression of diabetic nephropathy through miR-136-5p/PAQR3 axis

BACKGROUND

Diabetic nephropathy (DN) is one of the complications of diabetes and has a high mortality, but its specific pathogenesis is not clear. In recent years, researches on the mechanism of circRNAs in DN have been proved a lot, whereas the functional mechanism of circ_0003928 in DN remains open and it must be investigated to value its important role in DN prevention.

METHODS

HK-2 cells were treated with high glucose (HG), normal glucose (NG) or Mannitol. Cell counting kit-8 (CCK8) and 5-ethynyl-2'-deoxyuridine (EdU) assays were performed to detect cell proliferation. Enzyme-linked immunosorbent assay (ELISA) was applied to analyze malondialdehyde (MDA) and superoxide dismutase 1 (SOD) levels. Flow cytometry and western blot were preformed to measure cell apoptosis. Real-time quantitative PCR (RT-qPCR) was used to test the levels of circ_0003928, miR-136-5p and progestin and adipoQ receptor family member 3 (PAQR3) mRNA. Western blot was executed to detect Bcl2 associated X (Bax), B cell leukemia/lymphoma 2 (Bcl2), smooth muscle (αSMA), apolipoprotein (C-IV) and PAQR3 levels. Luciferase reporter assay and RNA pull-down assay were used to analyze the target relationship between miR-136-5p and circ_0003928 or PAQR3.

RESULTS

Circ_0003928 and PAQR3 expression were up-regulated, whereas miR-136-5p was decreased in DN serum and HG-induced HK-2 cells. Circ_0003928 knockdown promoted cell proliferation, and inhibit cell apoptosis, oxidative stress, and fibrosis in HK-2 cells under HG condition. MiR-136-5p silencing overturned the protective effects of si-circ_0003928 on HG-induced HK-2 cells. MiR-136-5p was targeted by circ_0003928 and directly targeted PAQR3. Overexpression of PAQR3 counteracted the inhibitory functions of circ_0003928 knockdown or miR-136-5p overexpression on HG-induced HK-2 cell injury.

CONCLUSION

Circ_0003928 acted as a sponge of miR-136-5p to up-regulating PAQR3 expression, and then regulate the proliferation, oxidative stress, fibrosis and apoptosis in HG-induced HK-2 cells.

Identification of endoplasmic reticulum stress-related biomarkers of diabetes nephropathy based on bioinformatics and machine learning

Backgrounds

Diabetes nephropathy (DN) is a growing public health concern worldwide. Renal dysfunction impairment in DN is intimately linked to ER stress and its related signaling pathways. Nonetheless, the underlying mechanism and biomarkers for this function of ER stress in the DN remain unknown.

Methods

Microarray datasets were retrieved from the Gene Expression Omnibus (GEO) database, and ER stress-related genes (ERSRGs) were downloaded from the MSigDB and GeneCards database. We identified hub ERSRGs for DN progression by intersecting ERSRGs with differentially expressed genes and significant genes in WGCNA, followed by a functional analysis. After analyzing hub ERSRGs with three machine learning techniques and taking the intersection, we did external validation as well as developed a DN diagnostic model based on the characteristic genes. Immune infiltration was performed using CIBERSORT. Moreover, patients with DN were then categorized using a consensus clustering approach. Eventually, the candidate ERSRGs-specific small-molecule compounds were defined by CMap.

Results

Several biological pathways driving pathological injury of DN and disordered levels of immune infiltration were revealed in the DN microarray datasets and strongly related to deregulated ERSRGs by bioinformatics multi-chip integration. Moreover, CDKN1B, EGR1, FKBP5, GDF15, and MARCKS were identified as ER stress signature genes associated with DN by machine learning algorithms, demonstrating their potential as DN biomarkers.

Conclusions

Our research sheds fresh light on the function of ER stress in DN pathophysiology and the development of early diagnostic and ER stress-related treatment targets in patients with DN.

Lncrna CASC11 aggravates diabetic nephropathy via targeting FoxO1

Background

To explore the biological effects of CASC11 on aggravating diabetic nephropathy (DN) by regulating FoxO1 (forkhead transcription factor O1).

Methods

Serum levels of CASC11 and FoxO1 in DN patients were detected. The possibility of CASC11 in predicting the onset of DN was analyzed by depicting ROC curves. Correlation between CASC11 and FoxO1 was evaluated by Pearson correlation test. After intervening CASC11 and FoxO1 levels, we found that changes in proliferative and migratory abilities in high glucose (HG)induced kidney mesangial cells were determined respectively. Protein levels of TGF-β1 and Smads regulated by both CASC11 and FoxO1 were examined by Western blot.

Epigenetic modification in diabetic kidney disease

Diabetic kidney disease (DKD) is a common microangiopathy in diabetic patients and the main cause of death in diabetic patients. The main manifestations of DKD are proteinuria and decreased renal filtration capacity. The glomerular filtration rate and urinary albumin level are two of the most important hallmarks of the progression of DKD. The classical treatment of DKD is controlling blood glucose and blood pressure. However, the commonly used clinical therapeutic strategies and the existing biomarkers only partially slow the progression of DKD and roughly predict disease progression. Therefore, novel therapeutic methods, targets and biomarkers are urgently needed to meet clinical requirements. In recent years, increasing attention has been given to the role of epigenetic modification in the pathogenesis of DKD. Epigenetic variation mainly includes DNA methylation, histone modification and changes in the noncoding RNA expression profile, which are deeply involved in DKD-related inflammation, oxidative stress, hemodynamics, and the activation of abnormal signaling pathways. Since DKD is reversible at certain disease stages, it is valuable to identify abnormal epigenetic modifications as early diagnosis and treatment targets to prevent the progression of end-stage renal disease (ESRD). Because the current understanding of the epigenetic mechanism of DKD is not comprehensive, the purpose of this review is to summarize the role of epigenetic modification in the occurrence and development of DKD and evaluate the value of epigenetic therapies in DKD.

Green-synthesized nanoparticles of the polyherbal extract attenuate the necrosis of pancreatic β-cell in a streptozotocin-induced diabetic model

Plant-based nanoformulation is one of the novel approaches for therapeutic benefits. This research synthesized a silver nanoparticle from the polyherbal combination of four plants/seeds (Momordica charantia, Trigonella foenum-graecum, Nigella sativa, and Ocimum sanctum) and investigated its antidiabetic effects in streptozotocin-induced Wistar albino rat model. The polyherbal extract (PH) was extracted by the Soxhlet-solvent extraction method and the resulting crude extract was undergone for silver nanoparticle synthesis. The PH extract was subjected to a four-week intervention in fructose-fed streptozotocin-induced Wistar Albino rats' models and in vitro antioxidative tests. Experimental animals (age: 6-7 weeks, male, body weight: 200-220 g), were divided into five groups including normal control (NC), reference control (RC), diabetic control (DC), and treatment groups PH200, PH100, and PHAgNP20. After three weeks of intervention, body weight, weekly blood glucose level, oral glucose tolerance test, AST, ALT, alkaline phosphatase, total cholesterol, triglycerides, uric acid, urea, and creatinine level of PH200 were found to be significantly (P < 0.05) improved compared to the diabetic control. The same dose demonstrated better regeneration of damaged pancreatic and kidney tissues. In vitro antioxidant assay manifested promising IC50 values of 86.17 μg/mL for DPPH, 711.04 μg/mL for superoxide free radical, and 0.48 mg/mL for Iron chelating activity of the polyherbal extract. GC-MS analysis impacted the major volatile compounds of the PH. The data demonstrate that the PH and its nanoparticles could be a novel source of antidiabetic therapeutics through an advanced dose-response study in the type 2 diabetic model.

Human Umbilical Cord Mesenchymal Stem Cells Inhibit Pyroptosis of Renal Tubular Epithelial Cells through miR-342-3p/Caspase1 Signaling Pathway in Diabetic Nephropathy

Diabetic nephropathy (DN) is one of the microvascular complications of diabetes. Recent studies suggest that the pyroptosis of renal tubular epithelial cell plays a critical role in DN. Currently, effective therapeutic strategies to counteract and reverse the progression of DN are lacking. Mesenchymal stem cells (MSCs) represent an attractive therapeutic tool for tissue damage and inflammation owing to their unique immunomodulatory properties. However, the underlying mechanisms remain largely unknown. In the present study, we found that human umbilical cord MSCs (UC-MSCs) can effectively ameliorate kidney damage and reduce inflammation in DN rats. Importantly, UC-MSC treatment inhibits inflammasome-mediated pyroptosis in DN. Mechanistically, we performed RNA sequencing and identified that miR-342-3p was significantly downregulated in the kidneys of DN rats. Furthermore, we found that miR-342-3p was negatively correlated with renal injury and pyroptosis in DN rats. The expression of miR-342-3p was significantly increased after UC-MSC treatment. Moreover, miR-342-3p decreased the expression of Caspase1 by targeting its 3 $\prime$ -UTR, which was confirmed by double-luciferase assay. Using miRNA mimic transfection, we demonstrated that UC-MSC-derived miR-342-3p inhibited pyroptosis of renal tubular epithelial cells through targeting the NLRP3/Caspase1 pathway. These findings would provide a novel intervention strategy for the use of miRNA-modified cell therapy for kidney diseases.

The Role of MicroRNA in the Pathogenesis of Diabetic Nephropathy

Diabetic nephropathy is one of the most common and severe complications of diabetes mellitus, affecting one in every five patients suffering from diabetes. Despite extensive research, the exact pathogenesis of diabetic nephropathy is still unclear. Several factors and pathways are known to be involved in the development of the disease, such as reactive oxygen species or the activation of the renin–angiotensin–aldosterone system. The expression of those proteins might be extensively regulated by microRNA. Recent research suggests that in diabetic nephropathy patients, the profile of miRNA is significantly changed. In this review, we focus on the actions of miRNA in various pathways involved in the pathogenesis of diabetic nephropathy and the clinical usage of miRNAs as biomarkers and therapeutic targets.

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.

Treatment of Diabetes Nephropathy in Mice by Germinating Seeds of Euryale ferox through Improving Oxidative Stress

Diabetes can cause severe kidney disease. Euryale ferox seeds (Gordon Euryale) have known antioxidant, hypoglycemic, and renal protection effects. Methanol extracts of Gordon Euryale were produced from ungerminated and germinated seeds. The effect of germination on polyphenol and flavonoid content was investigated by Liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. Three doses of ungerminated seed extract (EKE) and germinated seed extract (GEKE) were administered to diabetic mice by gavage to explore the treatment-dependent improvement of oxidative stress, metabolic disorder, and kidney disease. Seed germination led to a 1.7 times increase in total phenol content in the extract, and the flavonoid content was increased by 1.9 times. Germination greatly increased the contents of 29 polyphenols and 1 terpenoid. At the same dose, GEKE more strongly improved hyperglycemia, abnormal lipid metabolism, and renal tissue lesions (as confirmed by histology) in the diabetic mice than EKE did. In diabetic mice receiving treatment, kidney microalbunminuria (ALB), blood urea nitrogen (BUN), serum creatinine (Scr), malondialdehyde (MDA), and glutathione (GSH) were all decreased, while activity of catalase (CAT), superoxide dismutase (SOD), and serum total antioxidant capacity (T-AOC) were increased. Both EKE and GEKE can improve diabetes and kidney disease by improving hyperglycemia, oxidative stress, and kidney physiological indicators and regulating the Keap1/Nrf2/HO-1 and AMPK/mTOR pathways. However, in both pathways, GEKE is more effective. The purpose of this study was to explore the effects of GEKE and EKE treatment on antioxidant defense and metabolic capacity of diabetic animals. Germination provides a suitable strategy to improve the medicinal value of these natural plant-based products.

Sestrin2 Signaling Pathway Regulates Podocyte Biology and Protects against Diabetic Nephropathy

Sestrin2 regulates cell homeostasis and is an upstream signaling molecule for several signaling pathways. Sestrin2 leads to AMP-activated protein kinase- (AMPK-) and GTPase-activating protein activity toward Rags (GATOR) 1-mediated inhibition of mammalian target of rapamycin complex 1 (mTORC1), thereby enhancing autophagy. Sestrin2 also improves mitochondrial biogenesis via AMPK/Sirt1/peroxisome proliferator-activated receptor-gamma coactivator 1 alpha (PGC-1α) signaling pathway. Blockade of ribosomal protein synthesis and augmentation of autophagy by Sestrin2 can prevent misfolded protein accumulation and attenuate endoplasmic reticulum (ER) stress. In addition, Sestrin2 enhances P62-mediated autophagic degradation of Keap1 to release nuclear factor erythroid 2-related factor 2 (Nrf2). Nrf2 release by Sestrin2 vigorously potentiates antioxidant defense in diabetic nephropathy. Impaired autophagy and mitochondrial biogenesis, severe oxidative stress, and ER stress are all deeply involved in the development and progression of diabetic nephropathy. It has been shown that Sestrin2 expression is lower in the kidney of animals and patients with diabetic nephropathy. Sestrin2 knockdown aggravated diabetic nephropathy in animal models. In contrast, upregulation of Sestrin2 enhanced autophagy, mitophagy, and mitochondrial biogenesis and suppressed oxidative stress, ER stress, and apoptosis in diabetic nephropathy. Consistently, overexpression of Sestrin2 ameliorated podocyte injury, mesangial proliferation, proteinuria, and renal fibrosis in animal models of diabetic nephropathy. By suppressing transforming growth factor beta (TGF-β)/Smad and Yes-associated protein (YAP)/transcription enhancer factor 1 (TEF1) signaling pathways in experimental models, Sestrin2 hindered epithelial-mesenchymal transition and extracellular matrix accumulation in diabetic kidneys. Moreover, modulation of the downstream molecules of Sestrin2, for instance, augmentation of AMPK or Nrf2 signaling and inhibition of mTORC1, has been protective in diabetic nephropathy. Regarding the beneficial effects of Sestrin2 on diabetic nephropathy and its interaction with several signaling molecules, it is worth targeting Sestrin2 in diabetic nephropathy.

A novel regulatory facet for hypertriglyceridemia: The role of microRNAs in the regulation of triglyceride-rich lipoprotein biosynthesis

Atherosclerotic cardiovascular disease (ASCVD) is one of the major leading global causes of death. Genetic and epidemiological studies strongly support the causal association between triacylglycerol-rich lipoproteins (TAGRL) and atherogenesis, even in statin-treated patients. Recent genetic evidence has clarified that variants in several key genes implicated in TAGRL metabolism are strongly linked to the increased ASCVD risk. There are several triacylglycerol-lowering agents; however, new therapeutic options are in development, among which are miRNA-based therapeutic approaches. MicroRNAs (miRNAs) are small non-coding RNAs (18-25 nucleotides) that negatively modulate gene expression through translational repression or degradation of target mRNAs, thereby reducing the levels of functional genes. MiRNAs play a crucial role in the development of hypertriglyceridemia as several miRNAs are dysregulated in both synthesis and clearance of TAGRL particles. MiRNA-based therapies in ASCVD have not yet been applied in human trials but are attractive. This review provides a concise overview of current interventions for hypertriglyceridemia and the development of novel miRNA and siRNA-based drugs. We summarize the miRNAs involved in the regulation of key genes in the TAGRLs synthesis pathway, which has gained attention as a novel target for therapeutic applications in CVD.

NUP160 knockdown inhibits the progression of diabetic nephropathy in vitro and in vivo

Diabetic nephropathy (DN) is a severe diabetic complication and podocyte damage is a hallmark of DN. The Nucleoporin 160 (NUP160) gene was demonstrated to regulate cell proliferation and apoptosis in mouse podocytes. This study explored the possible role and mechanisms of NUP160 in high glucose-triggered podocyte injury. A rat model of DN was established by intraperitoneal injection of 60 mg/kg streptozotocin (STZ). Podocytes were treated with 33 mM high glucose. The effects of the Nup160 on DN and its mechanisms were assessed using MTT, flow cytometry, Western blot, ELISA, RT-qPCR, and luciferase reporter assays. The in vivo effects of NUP160 were analyzed by HE, PAS, and MASSON staining assays. The NUP160 level was significantly upregulated in podocytes treated with 33 mM high glucose. Functionally, NUP160 knockdown alleviated high glucose-induced apoptosis and inflammation in podocytes. Mechanistically, miR-495-3p directly targeted NUP160, and lncRNA HCG18 upregulated NUP160 by sponging miR-495-3p by acting as a ceRNA. Additionally, NUP160 overexpression reversed the effects of HCG18 knockdown in high glucose treated-podocytes. The in vivo assays indicated that NUP160 knockdown alleviated the symptoms of DN rats. NUP160 knockdown plays a key role in preventing the progression of DN, suggesting that targeting NUP160 may be a potential therapeutic strategy for DN treatment.

Altered glucose metabolism in Alzheimer's disease: Role of mitochondrial dysfunction and oxidative stress

Increasing evidence suggests that abnormal cerebral glucose metabolism is largely present in Alzheimer's disease (AD). The brain utilizes glucose as its main energy source and a decline in its metabolism directly reflects on brain function. Weighing on recent evidence, here we systematically assessed the aberrant glucose metabolism associated with amyloid beta and phosphorylated tau accumulation in AD brain. Interlink between insulin signaling and AD highlighted the involvement of the IRS/PI3K/Akt/AMPK signaling, and GLUTs in the disease progression. While shedding light on the mitochondrial dysfunction in the defective glucose metabolism, we further assessed functional consequences of AGEs (advanced glycation end products) accumulation, polyol activation, and other contributing factors including terminal respiration, ROS (reactive oxygen species), mitochondrial permeability, PINK1/parkin defects, lysosome-mitochondrial crosstalk, and autophagy/mitophagy. Combined with the classic plaque and tangle pathologies, glucose hypometabolism with acquired insulin resistance and mitochondrial dysfunction potentiate these factors to exacerbate AD pathology. To this end, we further reviewed AD and DM (diabetes mellitus) crosstalk in disease progression. Taken together, the present work discusses the emerging role of altered glucose metabolism, contributing impact of insulin signaling, and mitochondrial dysfunction in the defective cerebral glucose utilization in AD.

NLRP3-mediated pyroptosis in diabetic nephropathy

Diabetic nephropathy (DN) is the main cause of end-stage renal disease (ESRD), which is characterized by a series of abnormal changes such as glomerulosclerosis, podocyte loss, renal tubular atrophy and excessive deposition of extracellular matrix. Simultaneously, the occurrence of inflammatory reaction can promote the aggravation of DN-induced kidney injury. The most important processes in the canonical inflammasome pathway are inflammasome activation and membrane pore formation mediated by gasdermin family. Converging studies shows that pyroptosis can occur in renal intrinsic cells and participate in the development of DN, and its activation mechanism involves a variety of signaling pathways. Meanwhile, the activation of the NOD-like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome can not only lead to the occurrence of inflammatory response, but also induce pyroptosis. In addition, a number of drugs targeting pyroptosis-associated proteins have been shown to have potential for treating DN. Consequently, the pathogenesis of pyroptosis and several possible activation pathways of NLRP3 inflammasome were reviewed, and the potential drugs used to treat pyroptosis in DN were summarized in this review. Although relevant studies are still not thorough and comprehensive, these findings still have certain reference value for the understanding, treatment and prognosis of DN.

Polyphenols target miRNAs as a therapeutic strategy for diabetic complications

MiRNAs are a large group of non-coding RNAs which participate in different cellular pathways like inflammation and oxidation through transcriptional, post-transcriptional, and epigenetic regulation. In the post-transcriptional regulation, miRNA interacts with the 3'-UTR of mRNAs and prevents their translation. This prevention or dysregulation can be a cause of pathological conditions like diabetic complications. A huge number of studies have revealed the association between miRNAs and diabetic complications, including diabetic nephropathy, cardiomyopathy, neuropathy, retinopathy, and delayed wound healing. To address this issue, recent studies have focused on the use of polyphenols as selective and safe drugs in the treatment of diabetes complications. In this article, we will review the involvement of miRNAs in diabetic complications' occurrence or development. Finally, we will review the latest findings on targeting miRNAs by polyphenols like curcumin, resveratrol, and quercetin for diabetic complications therapy.

MicroRNA-146a-5p-modified human umbilical cord mesenchymal stem cells enhance protection against diabetic nephropathy in rats through facilitating M2 macrophage polarization

Background

Diabetic nephropathy (DN) is a severe complication of diabetes mellitus and a common cause of end-stage renal disease (ESRD). Mesenchymal stem cells (MSCs) possess potent anti-inflammatory and immunomodulatory properties, which render them an attractive therapeutic tool for tissue damage and inflammation.

Methods

This study was designed to determine the protective effects and underlying mechanisms of human umbilical cord-derived MSCs (UC-MSCs) on streptozotocin-induced DN. Renal function and histological staining were used to evaluate kidney damage. RNA high-throughput sequencing on rat kidney and UCMSC-derived exosomes was used to identify the critical miRNAs. Co-cultivation of macrophage cell lines and UC-MSCs-derived conditional medium were used to assess the involvement of macrophage polarization signaling.

Results

UC-MSC administration significantly improved renal function, reduced the local and systemic inflammatory cytokine levels, and attenuated inflammatory cell infiltration into the kidney tissue in DN rats. Moreover, UC-MSCs shifted macrophage polarization from a pro-inflammatory M1 to an anti-inflammatory M2 phenotype. Mechanistically, miR-146a-5p was significantly downregulated and negatively correlated with renal injury in DN rats as determined through high-throughput RNA sequencing. Importantly, UC-MSCs-derived miR-146a-5p promoted M2 macrophage polarization by inhibiting tumor necrosis factor receptor-associated factor-6 (TRAF6)/signal transducer and activator of transcription (STAT1) signaling pathway. Furthermore, miR-146a-5p modification in UC-MSCs enhanced the efficacy of anti-inflammation and renal function improvement.

Conclusions

Collectively, our findings demonstrate that UC-MSCs-derived miR-146a-5p have the potential to restore renal function in DN rats through facilitating M2 macrophage polarization by targeting TRAF6. This would pave the way for the use of miRNA-modified cell therapy for kidney diseases.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-02855-7.

Eight Differential miRNAs in DN Identified by Microarray Analysis as Novel Biomarkers

BACKGROUND

Diabetic nephropathy (DN) is the common cause of renal diseases such as end-stage renal disease (ESRD) and chronic kidney disease (CKD). Various diagnostic applications and treatment methods are used for clinical but remain some prognosis issues. To avoid morbidity and mortality related to DN, early detection of disease complications as well as targeted therapeutic strategies is essential. Considerable evidence indicates that non-coding RNA plays a vital role in the biological processes of various diseases, used as biomarkers and therapeutic targets. And the most known ncRNAs are the microRNAs (miRNAs), long noncoding RNAs (lncRNAs), and circular RNAs (circRNAs).

MATERIALS AND METHODS

Our study aimed to identify potential prognostic ncRNAs involved in DN by bioinformatics analysis and validated expression levels through quantitative polymerase chain reaction (qPCR) and GEO database. Our research focuses on differential expression miRNAs (DEmiRNAs) in DN and their interactions with critical genes.

RESULTS

We identified 8 up-regulated DEmiRNAs, including miR-103a-2-5p, miR-297, miR-548x-3p, miR-604, miR-644a, miR-1256, miR-3911 and miR-5047 finally. We further validated these miRNAs in a murine model.

CONCLUSION

Identifying these up-regulated genes and elucidating these miRNAs regulatory network will contribute to a better understanding of the molecular mechanism of DN and how they can be used as new biomarkers and potential therapeutic targets for DN.

Epigenetics in the pathogenesis of diabetic nephropathy

Diabetic nephropathy (DN), which is a common microvascular complication with a high incidence in diabetic patients, greatly increases the mortality of patients. With further study on DN, it is found that epigenetics plays a crucial role in the pathophysiological process of DN. Epigenetics has an important impact on the development of DN through a variety of mechanisms, and promotes the generation and maintenance of metabolic memory, thus ultimately leading to a poor prognosis. In this review we discuss the methylation of DNA, modification of histone, and regulation of non-coding RNA involved in the progress of cell dysfunction, inflammation and fibrosis in the kidney, which ultimately lead to the deterioration of DN.

Exosomal hsa_circ_0125310 promotes cell proliferation and fibrosis in diabetic nephropathy via sponging miR-422a and targeting the IGF1R/p38 axis

Diabetic nephropathy (DN) is still on the rise worldwide, and millions of patients have to be treated through dialysis or transplant because of kidney failure caused by DN. Recent reports have highlighted circRNAs in the treatment of DN. Herein, we aimed to investigate the mechanism by which high glucose‐induced exo‐circ_0125310 promotes diabetic nephropathy progression. circ_0125310 is highly expressed in diabetic nephropathy and exosomes isolated from high glucose‐induced mesangial cells (MCs). High glucose‐induced exosomes promote the proliferation and fibrosis of MCs. However, results showed that the effects of exosomes on MCs can be reversed by the knockdown of circ_0125310. miR‐422a, which targets IGF1R, was the direct target of circ_0125310. circ_0125310 regulated IGF1R/p38 axis by sponging miR‐422a. Exo‐circ_0125310 increased the luciferase activity of the WT‐IGF1R reporter in the dual‐luciferase reporter gene assays and upregulated the expression level of IGF1R and p38. Finally, in vivo research indicated that the overexpression of circ_0125310 promoted the diabetic nephropathy progression. Above results demonstrated that the high glucose‐induced exo‐circ_0125310 promoted cell proliferation and fibrosis in diabetic nephropathy via sponging miR‐422a and targeting the IGF1R/p38 axis.

MicroRNA Expression Profiling in Diabetic Kidney Disease

The microRNAs (miRNAs) that can regulate diabetic kidney disease (DKD) have not been fully characterized. The aim of this study was to identify the miRNAs that affect DKD and could be used as specific biomarkers or therapeutic agents. First, kidney tissues from two DKD mouse models and control mice were screened for differences in miRNA expression by microarray analysis followed by quantitative real-time reverse transcription-PCR. Six miRNAs were differentially expressed from controls in both DKD mouse models. Among them, miRNA-125b-5p and miRNA-181b-5p were exclusively downregulated in the DKD mouse model. Next, we administered miRNA-181b-5p-mimic to DKD mice, which reduced the albuminuria and abnormal mesangial expansion. Pathway analysis and database research revealed that overexpression of miRNA-181b-5p significantly altered the expression of seven mRNAs in six known signaling pathways in the kidneys of DKD mice. Furthermore, the serum level of miRNA-125b-5p was significantly higher in patients with DKD (1.89±0.40-fold, P<0.05) compared with patients with other kidney diseases (0.94±0.13-fold) and healthy subjects (1.00±0.19-fold). Serum levels of miRNA-181b-5p were lower in patients with DKD (0.30±0.06-fold, P<0.05) compared with patients with other kidney diseases (1.06±0.20-fold) and healthy subjects (1.00±0.16-fold). These results suggest that miRNA-125b-5p and miRNA-181b-5p may represent novel diagnostic biomarkers and that miRNA-181b-5p may represent a therapeutic target for DKD.

Long noncoding RNA MIAT inhibits the progression of diabetic nephropathy and the activation of NF-κB pathway in high glucose-treated renal tubular epithelial cells by the miR-182-5p/GPRC5A axis

Background

Diabetic nephropathy (DN) is a common diabetic complication. Long noncoding RNAs (lncRNAs) have been identified as essential regulators in DN progression. This study is devoted to the research of lncRNA-myocardial infarction-associated transcript (MIAT) in DN.

Methods

DN cell model was established by high glucose (HG) treatment for human renal tubular epithelial cells (HK-2). Cell viability and colonizing capacity were analyzed by Cell Counting Kit-8 (CCK-8) and colony formation assay. Apoptosis was assessed via caspase-3 detection and flow cytometry. Enzyme-linked immunosorbent assay (ELISA) was used for evaluating inflammation. The protein determination was completed using western blot. MIAT, microRNA-182-5p (miR-182-5p), and G protein-coupled receptor class C group 5 member A (GPRC5A) levels were all examined via reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Intergenic binding was verified using dual-luciferase reporter, RNA immunoprecipitation (RIP), and RNA pull-down assays.

Results

HG induced the inhibition of cell growth, but accelerated apoptosis and inflammation as well as the activation of nuclear factor kappa B (NF-κB) pathway. MIAT reestablishment prevented the HG-induced cell damages and NF-κB signal activation. Mechanistically, MIAT was proved as a miR-182-5p sponge and regulated the expression of GPRC5A that was a miR-182-5p target. The rescued experiments demonstrated that MIAT downregulation or miR-182-5p upregulation aggravated the HG-induced cell damages and activated the NF-κB pathway via the respective regulation of miR-182-5p or GPRC5A.

Conclusion

Taken together, MIAT functioned as an inhibitory factor in the pathogenesis to impede the development of DN and inactivate the NF-κB pathway via regulating the miR-182-5p/GPRC5A axis.

miR-19a-3p downregulates tissue factor and functions as a potential therapeutic target for sepsis-induced disseminated intravascular coagulation

Sepsis-induced disseminated intravascular coagulation (DIC) is a common life-threatening terminal-stage disease with high mortality. This study aimed to identify effective miRNAs as therapeutic targets for DIC. Bioinformatics and luciferase reporter gene analyses were performed to predict miR-19a-3p and validate that it targets tissue factor (TF). Quantitative real-time PCR was used to detect the expression of miR-19a-3p and TF, and TF procoagulant activity was determined using the chromogenic substrate method. Western blotting was used to detect the protein levels of TF, AKT serine/threonine kinase (AKT), extracellular regulated protein kinases (ERK), nuclear factor kappa B (NF-κB) P65, NFKB inhibitor alpha (IκB-a) and their phosphorylated counterparts in cell experiments. Furthermore, a rat model was established to explore the potential of miR-19a-3p in DIC treatment. As a result, a human clinical study revealed that miR-19a-3p was downregulated and that TF was upregulated in neonates with sepsis-induced DIC compared with those in the control group. The luciferase reporter assay showed that TF was a direct target of miR-19a-3p. Cell experiments verified that the mRNA and protein levels of TF, and the p-AKT/AKT, p-Erk/Erk, p-P65/P65, p-IκB-a/IκB-a ratios, and TF procoagulant activity were significantly decreased in lipopolysaccharide (LPS) -induced human peripheral blood mononuclear cells (PBMCs) and human umbilical vein endothelial cells (HUVECs) inhibited by overexpression of miR-19a-3p, and that miR-19a-3p regulating TF was dependent on the NF-kB and AKT pathways. In vivo, miR-19a-3p injection into DIC rats suppressed the mRNA expression of TF; more importantly, significant improvements in coagulation function indicators and in histopathologies of lung and kidney were observed. In conclusion, miR-19a-3p may suppress DIC by targeting TF and might be a potential therapeutic target in treating sepsis-induced DIC.

Autophagy in the diabetic heart: A potential pharmacotherapeutic target in diabetic cardiomyopathy

Association of diabetes with an elevated risk of cardiac failure has been clinically evident. Diabetes potentiates diastolic and systolic cardiac failure following the myocardial infarction that produces the cardiac muscle-specific microvascular complication, clinically termed as diabetic cardiomyopathy. Elevated susceptibility of diabetic cardiomyopathy is primarily caused by the generation of free radicals in the hyperglycemic milieu, compromising the myocardial contractility and normal cardiac functions with increasing redox insult, impaired mitochondria, damaged organelles, apoptosis, and cardiomyocytes fibrosis. Autophagy is essentially involved in the recycling/clearing the damaged organelles, cytoplasmic contents, and aggregates, which are frequently produced in cardiomyocytes. Although autophagy plays a vital role in maintaining the cellular homeostasis in diligent cardiac tissues, this process is frequently impaired in the diabetic heart. Given its clinical significance, accumulating evidence largely showed the functional aspects of autophagy in diabetic cardiomyopathy, elucidating its intricate protective and pathogenic outcomes. However, etiology and molecular readouts of these contrary autophagy activities in diabetic cardiomyopathy are not yet comprehensively assessed and translated. In this review, we attempted to assess the role of autophagy and its adaptations in the diabetic heart. To delineate the molecular consequences of these events, we provided detailed insights into the autophagy regulation pieces of machinery including the mTOR/AMPK, TFEB/ZNSCAN3, FOXOs, SIRTs, PINK1/Parkin, Nrf2, miRNAs, and others in the diabetic cardiomyopathy. Given the clinical significance of autophagy in the diabetic heart, we further discussed the potential pharmacotherapeutic strategies towards targeting autophagy. Taken together, the present report meticulously assessed autophagy, its adaptations, and molecular regulations in diabetic cardiomyopathy and reviewed the current autophagy-targeting strategies.

Urinary sediment microRNAs can be used as potential noninvasive biomarkers for diagnosis, reflecting the severity and prognosis of diabetic nephropathy

BACKGROUND

Patients with both diabetes mellitus (DM) and kidney disease could have diabetic nephropathy (DN) or non-diabetic renal disease (NDRD). IgA nephropathy (IgAN) and membranous nephropathy (MN) are the major types of NDRD. No ideal noninvasive diagnostic model exists for differentiating them. Our study sought to construct diagnostic models for these diseases and to identify noninvasive biomarkers that can reflect the severity and prognosis of DN.

METHODS

The diagnostic models were constructed using logistic regression analysis and were validated in an external cohort by receiver operating characteristic curve analysis method. The associations between these microRNAs and disease severity and prognosis were explored using Pearson correlation analysis, Cox regression, Kaplan-Meier survival curves, and log-rank tests.

RESULTS

Our diagnostic models showed that miR-95-3p, miR-185-5p, miR-1246, and miR-631 could serve as simple and noninvasive tools to distinguish patients with DM, DN, DM with IgAN, and DM with MN. The areas under the curve of the diagnostic models for the four diseases were 0.995, 0.863, 0.859, and 0.792, respectively. The miR-95-3p level was positively correlated with the estimated glomerular filtration rate (p < 0.001) but was negatively correlated with serum creatinine (p < 0.01), classes of glomerular lesions (p < 0.05), and scores of interstitial and vascular lesions (p < 0.05). However, the miR-631 level was positively correlated with proteinuria (p < 0.001). A low miR-95-3p level and a high miR-631 level increased the risk of progression to end-stage renal disease (p = 0.002, p = 0.011).

CONCLUSIONS

These four microRNAs could be noninvasive tools for distinguishing patients with DN and NDRD. The levels of miR-95-3p and miR-631 could reflect the severity and prognosis of DN.

LncRNA TUG1/miR-29c-3p/SIRT1 axis regulates endoplasmic reticulum stress-mediated renal epithelial cells injury in diabetic nephropathy model in vitro

Long non-coding RNAs (lncRNAs) are important regulators in diabetic nephropathy. In this study, we investigated the potential role of lncRNA TUG1 in regulating endoplasmic reticulum stress (ERS)-mediated apoptosis in high glucose induced renal tubular epithelial cells. Human renal tubular epithelial cell line HK-2 was challenged with high glucose following transfection with lncRNA TUG1, miR-29c-3p mimics or inhibitor expression plasmid, either alone or in combination, for different experimental purposes. Potential binding effects between TUG1 and miR-29c-3p, as well as between miR-29c-3p and SIRT1 were verified. High glucose induced apoptosis and ERS in HK-2 cells, and significantly decreased TUG1 expression. Overexpressed TUG1 could prevent high glucose-induced apoptosis and alleviated ERS via negatively regulating miR-29c-3p. In contrast, miR-29c-3p increased HK-2 cells apoptosis and ERS upon high glucose-challenge. SIRT1 was a direct target gene of miR-29c-3p in HK-2 cells, which participated in the effects of miR-29c-3p on HK-2 cells. Mechanistically, TUG1 suppressed the expression of miR-29c-3p, thus counteracting its function in downregulating the level of SIRT1. TUG1 regulates miR-29c-3p/SIRT1 and subsequent ERS to relieve high glucose induced renal epithelial cells injury, and suggests a potential role for TUG1 as a promising diagnostic marker of diabetic nephropathy.

Identification and construction of lncRNA-associated ceRNA network in diabetic kidney disease

Diabetic kidney disease (DKD) has become the major contributor to end-stage renal disease with high incidence and mortality. The functional roles and exact mechanisms of long noncoding RNA (lncRNA)-associated competing endogenous RNA (ceRNA) network in DKD are still largely unknown. This study sought to discover novel potential biomarkers and ceRNA network for DKD.The candidate differentially expressed genes (DEGs), lncRNAs and microRNAs (miRNAs) in human glomerular and tubular tissues derived from Gene Expression Omnibus database were systematically selected and analyzed. Functional enrichment analysis and protein-protein interaction network analysis were conducted to identify hub genes and reveal their regulatory mechanisms involved in DKD. Following this, the integrated ceRNA network was constructed by bioinformatics methods.A total of 164 DEGs, 6 lncRNAs and 18 miRNAs correlated with DKD were finally filtered and identified. It is noteworthy that the global lncRNA-associated ceRNA network related to DKD was constructed, among which lnc-HIST2H2AA4-1, VCAN-AS1 and MAGI2-AS1 were identified as the 3 key lncRNAs, and VCAN, FN1, CCL2, and KNG1 were identified as the predominant genes. Consistent with that observed in the training set, 3 of the key genes also showed significant differences in the 2 validation datasets. Integrating with functional enrichment analysis results, these key genes in the ceRNA network were mainly enriched in the immune and inflammation-related pathways.This study first identified key lncRNAs, miRNAs and their targets, and further revealed a global view of lncRNA-associated ceRNA network involved in DKD by using whole gene transcripts analysis.

The Role of microRNAs in the Development of Type 2 Diabetes Complications

MicroRNAs represent a class of small (19-25 nucleotides) single-strand pieces of RNA that are noncoding ones. They are synthesized by RNA polymerase II from transcripts that fold back on themselves. They mostly act as gene regulatory agents that pair with complementary sequences on mRNA and produce silencing complexes, which, in turn, suppress coding genes at a post-transcriptional level. There is now evidence that microRNAs may affect insulin secretion or insulin action, as they can alter pancreatic beta cells development, insulin production, as well as insulin signaling. Any molecular disorder that affects these pathways can deteriorate insulin resistance and lead to type 2 diabetes mellitus (T2DM) onset. Furthermore, the expression of several microRNAs is up- or down-regulated in the presence of diabetic microvascular complications (i.e., peripheral neuropathy, nephropathy, retinopathy, foot ulcers), as well as in patients with coronary heart disease, stroke, and peripheral artery disease. However, more evidence is needed, specifically regarding T2DM patients, to establish the use of such microRNAs as diagnostical biomarkers or therapeutic targets in daily practice.

MiR-770-5p facilitates podocyte apoptosis and inflammation in diabetic nephropathy by targeting TIMP3

OBJECTIVE

Diabetic nephropathy (DN) is one of the most severe and frequent diabetic complications. MicroRNAs (miRNAs) have been reported to play a vital role in DN pathogenesis. The present study aimed to investigate the molecular mechanism of miR-770-5p in DN.

METHODS

Podocyte injury model was established by treating mouse podocytes with high glucose (HG, 33 mM) for 24 h. The levels of miR-770-5p and TIMP3 were examined in kidney tissues and podocytes using quantitative real-time PCR (qRT-PCR). Flow cytometry analysis was applied to detect apoptosis in podocytes. Western blot assay was used to measure the protein levels of B-cell lymphoma 2 (Bcl-2), Bcl-2 associated X (Bax) and tissue inhibitors of metalloproteinase 3 (TIMP3). Enzyme-linked immunosorbent assay (ELISA) was conducted to measure the levels of inflammatory factors. The interaction between miR-770-5p and TIMP3 was determined by MicroT-CDS and luciferase reporter assay.

RESULTS

MiR-770-5p was up-regulated and TIMP3 was down-regulated in DN kidney tissues and HG-stimulated podocytes. Depletion of miR-770-5p suppressed cell apoptosis and the release of pro-inflammatory factors in HG-treated podocytes. Additionally, TIMP3 was a target of miR-770-5p in HG-treated podocytes. TIMP3 inhibited cell apoptosis and inflammation in HG-treated podocytes. Moreover, TIMP3 knockdown alleviated the inhibitory effect of miR-770-5p silencing on podocyte apoptosis and inflammatory response.

CONCLUSION

Knockdown of miR-770-5p suppressed podocyte apoptosis and inflammatory response by targeting TIMP3 in HG-treated podocytes, indicating that miR-770-5p may be a potential therapeutic target for DN therapy.

Inhibition of miRNA-155 Alleviates High Glucose-Induced Podocyte Inflammation by Targeting SIRT1 in Diabetic Mice

OBJECTIVE

Microinflammation plays a crucial role in podocyte dysfunction in diabetic nephropathy, but its regulatory mechanism is still unclear. This study is aimed at discussing the mechanisms underlying the effect of miRNA-155 on podocyte injury to determine its potential as a therapeutic target.

METHODS

Cultured immortalized mouse podocytes and diabetic KK-Ay mice models were treated with a miR-155 inhibitor. Western blotting, real-time PCR, ELISA, immunofluorescence, and Luciferase reporter assay were used to analyze markers of inflammation cytokines and podocyte injury.

RESULTS

miRNA-155 was found to be highly expressed in serum and kidney tissue of mice with diabetic nephropathy and in cultured podocytes, accompanied by elevated levels of inflammatory factors. Inhibition of miRNA-155 can reduce proteinuria and ACR levels, diminish the secretion of inflammatory molecules, improve kidney function, inhibit podocyte foot fusion, and reverse renal pathological changes in diabetic nephropathy mice. Overexpression of miRNA-155 in vitro can increase inflammatory molecule production in podocytes and aggravates podocyte injury, while miRNA-155 inhibition suppresses inflammatory molecule production in podocytes and reduces podocyte injury. A luciferase assay confirmed that miRNA-155 could selectively bind to 3'-UTR of SIRT1, resulting in decreased SIRT1 expression. In addition, SIRT1 siRNA could offset SIRT1 upregulation and enhance inflammatory factor secretion in podocytes, induced by the miRNA-155 inhibitor.

CONCLUSIONS

These findings strongly support the hypothesis that miRNA-155 inhibits podocyte inflammation and reduces podocyte injury through SIRT1 silencing. miRNA-155 suppression therapy may be useful for the management of diabetic nephropathy.

Mitochondrial dysfunction, mitophagy, and role of dynamin-related protein 1 in Alzheimer's disease

Alzheimer's disease (AD) is the most common type of dementia and progressive neurodegenerative disease. The presence of β-amyloid (Aβ) plaques and phosphorylated Tau tangles are considered to be the two main hallmarks of AD. Recent findings have shown that different changes in the structure and dynamics of mitochondria play an important role in AD pathology progression. Mitochondrial changes in AD are expressed as enhanced mitochondrial fragmentation, altered mitochondrial dynamics, and changes in the expression of mitochondrial biogenesis genes in vitro and in vivo models. Therefore, targeting mitochondria and associated mitochondrial proteins seems to be a promising alternative instead of targeting Aβ and Tau in the prevention of Alzheimer's disease. The dynamin-related protein (Drp1) is one such protein that plays an important role in the regulation of mitochondrial division and maintenance of mitochondrial structures. Few researchers have shown that inhibition of Drp1 GTPase activity in neuronal cells rescues excessive mitochondrial fragmentation. In addition, the growing evidence revealed that Drp1 can interact with both Aβ and Tau protein in human brain tissues and mouse models. In this review, we would like to update existing knowledge about various changes in and around mitochondria related to the pathogenesis of Alzheimer's disease, with particular emphasis on mitophagy and autophagy.

Myricitrin, a Glycosyloxyflavone in Myrica esculenta Bark Ameliorates Diabetic Nephropathy via Improving Glycemic Status, Reducing Oxidative Stress, and Suppressing Inflammation

The present study evaluated the therapeutic potential of myricitrin (Myr), a glycosyloxyflavone extracted from Myrica esculenta bark, against diabetic nephropathy. Myr exhibited a significant hypoglycemic effect in high fat-fed and a single low-dose streptozotocin-induced type 2 diabetic (T2D) rats. Myr was found to improve glucose uptake by the skeletal muscle via activating IRS-1/PI3K/Akt/GLUT4 signaling in vitro and in vivo. Myr significantly attenuated high glucose (HG)-induced toxicity in NRK cells and in the kidneys of T2D rats. In this study, hyperglycemia caused nephrotoxicity via endorsing oxidative stress and inflammation resulting in the induction of apoptosis, fibrosis, and inflammatory damages. Myr was found to attenuate oxidative stress via scavenging/neutralizing oxidative radicals and improving endogenous redox defense through Nrf-2 activation in both in vitro and in vivo systems. Myr was also found to attenuate diabetes-triggered renal inflammation via suppressing NF-κB activation. Myr inhibited hyperglycemia-induced apoptosis and fibrosis in renal cells evidenced by the changes in the expressions of the apoptotic and fibrotic factors. The molecular docking predicted the interactions between Myr and different signal proteins. An in silico absorption, distribution, metabolism, excretion, and toxicity (ADMET) study predicted the drug-likeness character of Myr. Results suggested the possibility of Myr to be a potential therapeutic agent for diabetic nephropathy in the future.

New insights into diabetes mellitus and its complications: a narrative review

Diabetes is a metabolic disorder accompanied by complications of multiple organs and systems. Diabetic nephropathy (DN) is one of the most prevalent lethal complications of diabetes. Although numerous biomarkers have be clarified for early diagnosis of DN, renal biopsy is still the gold standard. As a noninvasive imaging diagnostic method, blood oxygen level-dependent (BOLD) MRI can help understand the kidney oxygenation status and fibrosis process and monitor the efficacy of new drugs for DN via monitoring renal blood oxygen levels. Recent studies have shown that noncoding RNAs including microRNAs (miRNAs), long noncoding RNAs (lncRNAs) and circular RNAs (circRNAs) were all involved in the development of DN, which could be exploited as therapeutic strategy to control DN. Dyslipidemia is also a common complication of diabetes. Apolipoprotein M (apoM), as a novel apolipoprotein, may be related to the development and progression of diabetes, which need to further investigation. Obstructive sleep apnea (OSA) is another common complication of diabetes and is an independent risk factor for cardiovascular disease (CVD). At present, there is no simple, effective and rapid diagnostic method to early identification of OSA in patients with diabetes. A nomogram consisted of waist-to-hip ratio, smoking status, body mass index, serum uric acid, HOMA-IR and history of fatty liver might be an alternative method to early assess the risk of OSA.

MicroRNA-30/Cx43 axis contributes to podocyte injury by regulating ER stress in diabetic nephropathy

Background

The microRNA-30 family plays a critical role in the pathogenesis of podocyte injury. Cx43 plays an essential role in intercellular communication, which is essential for coordinated kidney function. This study was conducted to explore the function of microRNA-30s/Cx43 in podocyte injury in diabetic nephropathy (DN), both in vivo and in vitro.

Methods

SD rats were given streptozotocin (STZ) injections to induce DN. Podocytes were incubated in the medium in the presence or absence of high glucose (HG). The effects of the microRNA-30/Cx43 axis on DN and its underlying mechanisms were investigated by TUNEL assay, PAS, immunohistochemical staining, immunofluorescence staining, Western blot, RT-qPCR, RNA interference, and luciferase reporter assay. Podocytes were transfected with microRNA-30 family mimics, microRNA-30 family inhibitors, Cx43 siRNA, and negative controls to detect the effect of the microRNA-30/Cx43 axis. MicroRNA-30 family mimic AAVs, and microRNA-30 family inhibitor AAVs applied to regulate microRNA-30 family expression in the kidneys of the STZ-induced DN model rats to reveal the underlying mechanisms of the microRNA-30/Cx43 axis in DN.

Results

MicroRNA-30 family member expression was downregulated in HG-treated podocytes and the glomeruli of STZ-induced DN rats. Luciferase reporter assays confirmed Cx43 is a directed target of microRNA-30s. The overexpression of microRNA-30 family members attenuated the HG-induced podocyte injury and protected against podocyte apoptosis and endoplasmic reticulum stress (ERS) both in vivo and in vitro. Also, silencing Cx43 expression eased podocyte apoptosis, injury, and ERS induced by a HG+microRNA-30 family inhibitor. Double-immunofluorescence staining assays proved the co-localization of caspase12 and Cx43.

Conclusions

The overexpression of microRNA-30 family members prevents HG-induced podocyte injury and attenuates ERS by modulating Cx43 expression. The microRNA-30/Cx43/ERS axis might be a potential therapeutic target to treat DN.

Research Status of Differentially Expressed Noncoding RNAs in Type 2 Diabetes Patients

AIMS

Noncoding RNAs (ncRNAs) play an important role in the occurrence and development of type 2 diabetes mellitus (T2DM). This paper summarized the current evidences of the involvement microRNAs, long noncoding RNAs (lncRNAs), and circular RNAs (circRNAs) in the differential expressions and their interaction with each other in T2DM.

METHODS

The differentially expressed miRNAs, lncRNAs, and circRNAs in the blood circulation (plasma, serum, whole blood, and peripheral blood mononuclear cells) of patients with T2DM were found in PubMed, GCBI, and other databases. The interactions between ncRNAs were predicted based on the MiRWalk and the DIANA Tools databases. The indirect and direct target genes of lncRNAs and circRNAs were predicted based on the starBase V2.0, DIANA Tools, and LncRNA-Target databases. Then, GO and KEGG analysis on all miRNA, lncRNA, and circRNA target genes was performed using the mirPath and Cluster Profile software package in R language. The lncRNA-miRNA and circRNA-miRNA interaction diagram was constructed with Cytoscape. The aim of this investigation was to construct a mechanism diagram of lncRNA involved in the regulation of target genes on insulin signaling pathways and AGE-RAGE signaling pathways of diabetic complications.

RESULTS

A total of 317 RNAs, 283 miRNAs, and 20 lncRNAs and circRNAs were found in the circulation of T2DM. Dysregulated microRNAs and lncRNAs were found to be involved in signals related to metabolic disturbances, insulin signaling, and AGE-RAGE signaling in T2DM. In addition, lncRNAs participate in the regulation of key genes in the insulin signaling and AGE-RAGE signaling pathways through microRNAs, which leads to insulin resistance and diabetic vascular complications.

CONCLUSION

Noncoding RNAs participate in the occurrence and development of type 2 diabetes and lead to its vascular complications by regulating different signaling pathways.

Celastrol slows the progression of early diabetic nephropathy in rats via the PI3K/AKT pathway

Background

Diabetic nephropathy serves as one of the most regular microvascular complications of diabetes mellitus and is the main factor that causes end-stage renal disease and incident mortality. As the beneficial effect and minute adverse influence of Celastrol on the renal system requires further elucidation, the renoprotective function of Celastrol in early diabetic nephropathy was investigated.

Methods

In high-fat and high-glucose diet/streptozotocin-induced diabetic rats which is the early diabetic nephropathy model, ALT, AST, 24 h urinary protein, blood urea nitrogen, and serum creatinine content were observed. Periodic acid-Schiff staining, enzyme-linked immunosorbent assay, immunohistochemical analysis, reverse transcription-polymerase chain reaction, and western blot analysis were used to explore the renoprotective effect of Celastrol to diabetic nephropathy rats and the underlying mechanism.

Results

High dose of Celastrol (1.5 mg/kg/d) not only improved the kidney function of diabetic nephropathy (DN) rats, and decreased the blood glucose and 24 h urinary albumin, but also increased the expression of LC3II and nephrin, and downregulated the expression of PI3K, p-AKT, and the mRNA level of NF-κB and mTOR.

Conclusion

Celastrol functions as a potential therapeutic substance, acting via the PI3K/AKT pathway to attenuate renal injury, inhibit glomerular basement membrane thickening, and achieve podocyte homeostasis in diabetic nephropathy.

MicroRNAs in diabetic nephropathy: From molecular mechanisms to new therapeutic targets of treatment

Despite considerable investigation in diabetic nephropathy (DN) pathogenesis and possible treatments, current therapies still do not provide competent prevention from disease progression to end-stage renal disease (ESRD) in most patients. Therefore, investigating exact molecular mechanisms and important mediators underlying DN may help design better therapeutic approaches for proper treatment. MicroRNAs (MiRNAs) are a class of small non-coding RNAs that play a crucial role in post-transcriptional regulation of many gene expression within the cells and present an excellent opportunity for new therapeutic approaches because their profile is often changed during many diseases, including DN. This review discusses the most important signaling pathways involved in DN and changes in miRNAs profile in each signaling pathway. We also suggest possible approaches for miRNA derived interventions for designing better treatment of DN.

MiR-21-5p directly contributes to regulating eNOS expression in human artery endothelial cells under normoxia and hypoxia

Clinical conditions associated with hypoxia and oxidative stress, such as fetal growth restriction (FGR), results in endothelial dysfunction. Previous reports show that changes in eNOS expression under these conditions are tightly controlled by DNA methylation and histone posttranslational modifications. However, the contribution of an orchestrating epigenetic mechanism, such as miRNAs, on the NO-related genes expression has not been addressed. We aimed to determine the levels of miRNAs highly expressed in normal endothelial cells (EC), miR-21 and miR-126, in FGR human umbilical artery EC (HUAEC), and their effects on hypoxia-dependent regulation of both, NO-related and oxidative stress-related genes. Results were validated by transcriptome analysis of HUAEC cultured under chronic low oxygen conditions. Cultured FGR-HUAEC showed decreased hsa-miR-21, DDAH1, SOD1, and NRF2, but increased miR-126, NOX4, and eNOS levels, compared with controls. MiR-21-5p levels in FGR were associated with increased hg-miR-21 gene promoter methylation, with no changes in hg-miR-126 gene promoter methylation. HUAEC exposed to hypoxia showed a transient increase in eNOS and DDAH11, paralleled by decrease miR-21-5p levels, but no changes in miR-126-3p and the other genes under study. Transcriptome profiling showed an inverse relationship among miR-21 and several transcripts targeted by miR-21 in HUAEC exposed to hypoxia, meanwhile miR-21-5p-mimic decreased eNOS and DDAH1 transcripts stability, blocking their induction by hypoxia. Consequently, FGR programs a hypoxia-related miRNA that contributes to the regulation of the NO pathway, involving a direct effect of miR-21-5p on eNOS transcript stability, not previously reported. Moreover, hypoxia downregulates miR-21-5p, contributing to increasing the expression of NO-related genes in arterial endothelial cells.

MicroRNAs in Podocyte Injury in Diabetic Nephropathy

Diabetic nephropathy is one of the major complications of diabetes mellitus and is the leading cause of end-stage renal disease worldwide. Podocyte injury contributes to the development of diabetic nephropathy. However, the molecules that regulate podocyte injury in diabetic nephropathy have not been fully clarified. MicroRNAs (miRNAs) are small non-coding RNAs that can inhibit the translation of target messenger RNAs. Previous reports have described alteration of the expression levels of many miRNAs in cultured podocyte cells stimulated with a high glucose concentration and podocytes in rodent models of diabetic nephropathy. The associations between podocyte injury and miRNA expression levels in blood, urine, and kidney in patients with diabetic nephropathy have also been reported. Moreover, modulation of the expression of several miRNAs has been shown to have protective effects against podocyte injury in diabetic nephropathy in cultured podocyte cells in vitro and in rodent models of diabetic nephropathy in vivo. Therefore, this review focuses on miRNAs in podocyte injury in diabetic nephropathy, with regard to their potential as biomarkers and miRNA modulation as a therapeutic option.

Psoralen alleviates high glucose-induced HK-2 cell injury by inhibition of Smad 2 signaling via upregulation of microRNA 874

Background

Diabetic nephropathy (DN) causes the vast proportion of excess mortality for patients with diabetes. Novel therapeutic approaches slowing down its incidence is still lacking. Psoralen is the major active ingredient of Psoralea corylifolia Linn. (PCL), which was used to treat a number of diseases. In this study, we aimed to investigate whether psoralen could alleviate DN using in vitro model.

Methods

Cell viability assay and immunofluorescence were used to evaluate the effect of psoralen on high glucose (HG)-stimulated human kidney HK-2 cells (48 h). RT-qPCR was used to detect the expressions of miRNA in cells. Cell transfection, apoptosis assay, inflammatory cytokines detection and Western blot were further performed to explore the underlying molecular mechanisms.

Results

HG-induced toxicity of HK-2 cells was alleviated by psoralen. Meanwhile, the secretion of inflammatory cytokines and extracellular matrix (ECM) accumulation induced by HG in HK-2 cells were also decreased by psoralen. In addition, the expression of miR-874 in HK-2 cells was significantly upregulated by psoralen. Western blot assays indicated that psoralen could reverse HG-induced increase of TLR-4/NF-κB and Smad2 via upregulation of miR-874.

Conclusion

This study demonstrated that psoralen could significantly alleviate HG-induced HK-2 cell injury via upregulation of miR-874. In addition, HG-induced increase of TLR-4/NF-κB and Smad2 was revered by psoralen. Therefore, psoralen might serve as an agent for the treatment of DN.

MicroRNA-770-5p contributes to podocyte injury via targeting E2F3 in diabetic nephropathy

Diabetic nephropathy (DN) has been identified as the major cause of end-stage renal disease (ESRD) in most developed countries. MicroRNA-770-5p depletion could repress high glucose (HG)-triggered apoptosis in podocytes, and downregulation of E2F transcription factor 3 (E2F3) could facilitate podocyte injury. Nevertheless, whether E2F3 is involved in miR-770-5p knockdown-mediated improvement of DN is still unclear. The expression levels of miR-770-5p and E2F3 were detected in HG-treated podocytes by RT-qPCR. The expression levels of E2F3, apoptosis-related proteins Bcl-2 related X protein (Bax), B-cell lymphoma-2 (Bcl-2), Bad, apoptotic peptidase activating factor 1 (APAF1), C-caspase3, C-caspase7, and C-caspase9 were detected by western blot assay. The effects of miR-770-5p and E2F3 on HG-treated podocytes proliferation and apoptosis were detected by CCK-8 and flow cytometry assays. The interaction between miR-770-5p and E2F3 was predicted by Targetscan, and then verified by the dual-luciferase reporter assay. MiR-770-5p was upregulated and E2F3 was downregulated in HG-treated podocytes. MiR-770-5p inhibited proliferation and promoted apoptosis and E2F3 promoted proliferation and suppressed apoptosis in HG-treated podocytes. E2F3 is a target gene of miR-770-5p and it partially abolished the effect of miR-770-5p in HG-triggered proliferation and apoptosis of podocytes. MiR-770-5p deficiency blocked HG-induced APAF1/caspase9 pathway via targeting E2F3 in podocytes. We firstly confirmed that E2F3 was a target of miR-770-5p in podocytes. These findings suggested that miR-770-5p expedited podocyte injury by targeting E2F3, and the miR-770-5p/E2F3 axis might represent a pathological mechanism of DN progression.

Urinary exosomes: Potential biomarkers for diabetic nephropathy

Diabetic nephropathy is the most common diabetic complication culminating often into end-stage renal disease. Classically, it is defined by the presence of albuminuria which has limited ability to be detected at early stages but deterioration in kidney function generally precedes albuminuria. This necessitates the development of newer diagnostic assays for diabetic nephropathy to determine the progression of the disease. Kidney associated diseases with non-albuminuria further complicates a timely diagnosis and thus demands an early biomarker. Urinary exosomes, the nanovesicular entities are released by every epithelial cells of the nephron. Their protein or molecular cargo varies in the diseased state which may provide the pathophysiology of the kidney associated diseases. This drives them to be exploited as non-invasive biomarker. This review thus integrates the recent findings on the significance of the urinary exosomes as diagnostic biomarker in kidney-associated diseases, primarily in diabetic nephropathy.