Podocyte-specific deletion of miR-146a increases podocyte injury and diabetic kidney disease

Identification and Validation of T Cell-Related Hub Biomarkers for Early Diagnosis of Diabetic Kidney Disease Using Single-Cell and Bulk Dataset Analysis

Diabetic kidney disease (DKD) is the most common complication of diabetes and a leading cause of chronic kidney disease that frequently leads to end-stage renal disease (ESRD). The pathogenesis of DKD is complex and is not fully understood. This study was designed to identify key targets for DKD diagnosis and explore the underlying molecular mechanisms.

METHODS

DKD-specific clusters were selected from single-cell datasets. Gene modules were identified using hairpin-dynamic weighted gene co-expression network analysis (hdWGCNA). Multiple machine learning algorithms were applied to model and screen hub genes from two bulk datasets. Rat model of DKD was built using optical microscopes to observe the histopathological changes in the kidney by HE, PAS, and Masson staining. The expression of RASGRP3, PDE3B, and CD247 in DKD-Rat was verified by RT-PCR, and the expression of RASGRP3, PDE3B, and CD247 in the serum samples of DKD patients was verified by ELISA. The results of sex and age, RASGRP3, PDE3B, CD247 were calculated by multivariate logistic regression analysis.

RESULTS

Three hub genes were obtained through screening single-cell and two bulk datasets. In-depth exploration of the potential molecular mechanisms of the hub genes was conducted using gene set variation analysis (GSVA), immune infiltration analysis, and single-cell correlation analysis. Receiver operating characteristic (ROC) curve confirmed a high diagnostic value of the hub biomarkers, and a high-efficiency diagnostic model was constructed and mutually validated in the two datasets. We found that damaged tubular number and interstitial fibrotic percentage were significantly increased in DKD rat. As shown by HE, PAS and Masson staining, the mRNA levels of PDE3B and CD247 were markedly upregulated in DKD rat compared with those in the control group. Lower expression levels of RASGRP3 mRNA were manifested in DKD. The levels of RASGRP3, PDE3B, CD247 in DKD patients by ELISA were statistically significant (p < 0.05). PDE3B and CD247 had an AUC value greater than 0.9,RASGRP3 had an AUC value greater than 0.7.

CONCLUSION

This study identified 3 T cell-related hub biomarkers, providing references for the early diagnosis of DKD and changes in T cells during DKD progression.

MicroRNA193a: An Emerging Mediator of Glomerular Diseases

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

Broadening horizons: the contribution of mitochondria-associated endoplasmic reticulum membrane (MAM) dysfunction in diabetic kidney disease

Diabetic kidney disease (DKD) is a global health issue that presents a complex pathogenesis and limited treatment options. To provide guidance for precise therapies, it is crucial to accurately identify the pathogenesis of DKD. Several studies have recognized that mitochondrial and endoplasmic reticulum (ER) dysfunction are key drivers of the pathogenesis of DKD. The mitochondria-associated ER membrane (MAM) is a dynamic membrane contact site (MSC) that connects the ER and mitochondria and is essential in maintaining the normal function of the two organelles. MAM is involved in various cellular processes, including lipid synthesis and transport, calcium homeostasis, mitochondrial fusion and fission, and ER stress. Meanwhile, recent studies confirm that MAM plays a significant role in the pathogenesis of DKD by regulating glucose metabolism, lipid metabolism, inflammation, ER stress, mitochondrial fission and fusion, and autophagy. Herein, this review aims to provide a comprehensive summary of the physiological function of MAMs and their impact on the progression of DKD. Subsequently, we discuss the trend of pharmaceutical studies that target MAM resident proteins for treating DKD. Furthermore, we also explore the future development prospects of MAM in DKD research, thereby providing a new perspective for basic studies and clinical treatment of DKD.

Pediatric Diabetic Nephropathy: Novel Insights from microRNAs

Diabetic nephropathy (DN) represents the most common microvascular complication in patients with diabetes. This progressive kidney disease has been recognized as the major cause of end-stage renal disease with higher morbidity and mortality. However, its tangled pathophysiology is still not fully known. Due to the serious health burden of DN, novel potential biomarkers have been proposed to improve early identification of the disease. In this complex landscape, several lines of evidence supported a critical role of microRNAs (miRNAs) in regulating posttranscriptional levels of protein-coding genes involved in DN pathophysiology. Indeed, intriguing data showed that deregulation of certain miRNAs (e.g., miRNAs 21, -25, -92, -210, -126, -216, and -377) were pathogenically linked to the onset and the progression of DN, suggesting not only a role as early biomarkers but also as potential therapeutic targets. To date, these regulatory biomolecules represent the most promising diagnostic and therapeutic options for DN in adult patients, while similar pediatric evidence is still limited. More, findings from these elegant studies, although promising, need to be deeper investigated in larger validation studies. In an attempt to provide a comprehensive pediatric overview in the field, we aimed to summarize the most recent evidence on the emerging role of miRNAs in pediatric DN pathophysiology.