Circular RNAs in Diabetic Nephropathy: Updates and Perspectives

RNA-based diagnostic innovations: A new frontier in diabetes diagnosis and management

Background/Objective: Diabetes mellitus (DM) remains a major global health challenge due to its chronic nature and associated complications. Traditional diagnostic approaches, though effective, often lack the sensitivity required for early-stage detection. Recent advancements in molecular biology have identified RNA molecules, particularly non-coding RNAs such as microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), as promising biomarkers for diabetes. This review aims to explore the role of RNA-based biomarkers in the diagnosis, prognosis, and management of diabetes, highlighting their potential to revolutionize diabetes care.Method: A comprehensive literature review was conducted using electronic databases including PubMed, Scopus, and Web of Science. Articles published up to 2024 were screened and analyzed to extract relevant findings related to RNA-based diagnostics in diabetes. Emphasis was placed on studies demonstrating clinical utility, mechanistic insights, and translational potential of RNA molecules.Results: Numerous RNA species, particularly miRNAs such as miR-375, miR-29, and lncRNAs like H19 and MEG3, exhibit altered expression patterns in diabetic patients. These molecules are involved in key regulatory pathways of glucose metabolism, insulin resistance, and β-cell function. Circulating RNAs are detectable in various biofluids, enabling non-invasive diagnostic approaches. Emerging technologies, including RNA sequencing and liquid biopsy platforms, have enhanced the sensitivity and specificity of RNA detection, fostering the development of novel diagnostic tools and personalized therapeutic strategies.Conclusion: RNA-based biomarkers hold significant promise in advancing early detection, risk stratification, and therapeutic monitoring in diabetes care. Despite current challenges such as standardization and clinical validation, the integration of RNA diagnostics into routine clinical practice could transform diabetes management, paving the way for precision medicine approaches. Further research and multi-center trials are essential to validate these biomarkers and facilitate their regulatory approval and clinical implementation.

Inhibition of complement system-related gene ITGB2 attenuates epithelial-mesenchymal transition and inflammation in diabetic nephropathy

PURPOSE

Emerging evidences have indicated a role of the complement system in the pathogenesis of diabetic nephropathy (DN). Thus, this study was conducted to explore the complement system-related key biomarkers for patients with DN.

METHODS

DN microarray datasets were downloaded from the GEO database, followed by differentially expressed genes (DEGs) screening. Complement system-related genes (CSRGs) were searched from various databases. Weighted Gene Co-expression Network Analysis (WGCNA) was employed to screen the DN-related genes, then the differential CSRGs (DCSRGs) were identified, followed by protein-protein interaction (PPI) network construction. In addition, key biomarkers were acquired by two machine learning algorithms, then immune infiltration analysis, Gene Set Enrichment Analysis (GSEA), and potential drugs screening were conducted. Quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) and western blotting were utilized to detect the ITGB2 expression. Then the cell viability, inflammatory factors, and the expression of epithelial-mesenchymal transition (EMT) and fibrosis markers were determined by using Cell Counting Kit-8 (CCK-8) assay, enzyme linked immunosorbent assay (ELISA), western blotting assays, respectively.

RESULTS

In total, 1012 DEGs and 974 DN-related genes were screened, and intersection analysis of the three (DN-related genes, DEGs and CSRGs) yielded 13 intersection genes, which were considered as the DCSRGs. Subsequently, 2 key biomarkers were identified by machine learning, namely VWF and ITGB2. The VWF and ITGB2 were both enriched in the pathways of chemokine signaling pathway, CAMs, focal adhesion and natural killer cell-mediated cytotoxicity, and significantly correlated with the activated mast cells, resting NK cells, and macrophages. Also, VWF and ITGB2 were significantly related to the clinical features, including age, serum creatinine level, and GFR (MDRD). Besides, mRNA and protein expression levels of ITGB2 in HG-treated HK-2 cells were remarkably elevated. Moreover, the viability of HK-2 cells, expression of TNF-α, IL-6, IL-12, α-SMA, E-cadherin and vimentin in HK-2 cells changed by HG administration were reversed by ITGB2-silence.

CONCLUSION

Complement system-related gene ITGB2 was overexpressed in DN, and inhibition of ITGB2 attenuated EMT and inflammation in DN.

Circular RNAs in cancer

Circular RNA (circRNA), a subtype of noncoding RNA, has emerged as a significant focus in RNA research due to its distinctive covalently closed loop structure. CircRNAs play pivotal roles in diverse physiological and pathological processes, functioning through mechanisms such as miRNAs or proteins sponging, regulation of splicing and gene expression, and serving as translation templates, particularly in the context of various cancers. The hallmarks of cancer comprise functional capabilities acquired during carcinogenesis and tumor progression, providing a conceptual framework that elucidates the nature of the malignant transformation. Although numerous studies have elucidated the role of circRNAs in the hallmarks of cancers, their functions in the development of chemoradiotherapy resistance remain unexplored and the clinical applications of circRNA-based translational therapeutics are still in their infancy. This review provides a comprehensive overview of circRNAs, covering their biogenesis, unique characteristics, functions, and turnover mechanisms. We also summarize the involvement of circRNAs in cancer hallmarks and their clinical relevance as biomarkers and therapeutic targets, especially in thyroid cancer (TC). Considering the potential of circRNAs as biomarkers and the fascination of circRNA-based therapeutics, the "Ying-Yang" dynamic regulations of circRNAs in TC warrant vastly dedicated investigations.

Molecular Therapeutics for Diabetic Kidney Disease: An Update

Diabetic kidney disease (DKD) is a common microvascular complication of diabetes mellitus (DM). With the increasing prevalence of DM worldwide, the incidence of DKD remains high. If DKD is not well controlled, it can develop into chronic kidney disease or end-stage renal disease (ESRD), which places considerable economic pressure on society. Traditional therapies, including glycemic control, blood pressure control, blood lipid control, the use of renin-angiotensin system blockers and novel drugs, such as sodium-glucose cotransporter 2 inhibitors, mineralocorticoid receptor inhibitors and glucagon-like peptide-1 receptor agonists, have been used in DKD patients. Although the above treatment strategies can delay the progression of DKD, most DKD patients still ultimately progress to ESRD. Therefore, new and multimodal treatment methods need to be explored. In recent years, researchers have continuously developed new treatment methods and targets to delay the progression of DKD, including miRNA therapy, stem cell therapy, gene therapy, gut microbiota-targeted therapy and lifestyle intervention. These new molecular therapy methods constitute opportunities to better understand and treat DKD. In this review, we summarize the progress of molecular therapeutics for DKD, leading to new treatment strategies.

Circular RNAs and the regulation of gene expression in diabetic nephropathy (Review)

Circular RNAs (circRNAs) are non‑coding single‑stranded covalently closed RNA molecules that are considered important as regulators of gene expression at the transcriptional and post‑transcriptional levels. These molecules have been implicated in the initiation and progression of multiple human diseases, ranging from cancer to inflammatory and metabolic diseases, including diabetes mellitus and its vascular complications. The present article aimed to review the current knowledge on the biogenesis and functions of circRNAs, as well as their role in cell processes associated with diabetic nephropathy. In addition, novel potential interactions between circRNAs expressed in renal cells exposed to high‑glucose concentrations and the transcription factors c‑Jun and c‑Fos are reported.

Alisol A inhibits the circ_0001831/miR-346/LIN28B pathway to ameliorate high glucose-induced injury of human renal mesangial cells

BACKGROUND

Alisol A can ameliorate glucose metabolism disorders, however, there is no data regarding its role in diabetic nephropathy (DN). The present work evaluates the role of Alisol A in DN and the underlying mechanism.

METHODS

RNA expression of circ_0001831, miR-346, and lin-28 homolog B (LIN28B) was detected by qRT-PCR. Cell viability and proliferation were investigated by MTT assay and EdU assay, respectively. The inflammatory cytokines were examined by ELISAs. Oxidative stress was evaluated by the commercial kits. Protein expression was detected by western blotting. The interactions among circ_0001831, miR-346, and LIN28B were identified by dual-luciferase reporter assay and RIP assay. DN mouse model assay was used to analyse the effect of Alisol A on renal injury of diabetic mice.

RESULTS

HG treatment promoted HRMC proliferation, fibrosis, inflammation, and oxidative stress; however, these effects were reversed after Alisol A treatment. Alisol A treatment ameliorated STZ-induced renal injury of diabetic mice. Additionally, circ_0001831 or LIN28B overexpression or miR-346 downregulation relieved Alisol A-induced effects under HG conditions. Mechanistically, circ_0001831 acted as a miR-346 sponge, and LIN28B was identified as a target gene of miR-346. Further, the regulation of circ_0001831 in HG-induced HRMC dysfunction involved LIN28B.

CONCLUSION

Alisol A ameliorated HG-induced HRMC fibrosis, inflammation, and oxidative stress and STZ-induced renal injury of diabetic mice by regulating the circ_0001831/miR-346/LIN28B pathway.

Oxidative stress as a culprit in diabetic kidney disease

Diabetic kidney disease (DKD) has become the leading cause of end-stage renal disease (ESRD), and the prevalence of DKD has increased worldwide during recent years. DKD is associated with poor therapeutic outcomes in most patients, but there is limited understanding of its pathogenesis. This review suggests that oxidative stress interacts with many other factors in causing DKD. Highly active mitochondria and NAD(P)H oxidase are major sources of oxidants, and they significantly affect the risk for DKD. Oxidative stress and inflammation may be considered reciprocal causes of DKD, in that each is a cause and an effect of DKD. Reactive oxygen species (ROS) can act as second messengers in various signaling pathways and as regulators of metabolism, activation, proliferation, differentiation, and apoptosis of immune cells. Epigenetic modifications, such as DNA methylation, histone modifications, and non-coding RNAs can modulate oxidative stress. The development of new technologies and identification of new epigenetic mechanisms may provide novel opportunities for the diagnosis and treatment of DKD. Clinical trials demonstrated that novel therapies which reduce oxidative stress can slow the progression of DKD. These therapies include the NRF2 activator bardoxolone methyl, new blood glucose-lowering drugs such as sodium-glucose cotransporter 2 inhibitors, and glucagon-like peptide-1 receptor agonists. Future studies should focus on improving early diagnosis and the development of more effective combination treatments for this multifactorial disease.