Renal Megalin mRNA Downregulation Is Associated with CKD Progression in IgA Nephropathy

The Expression of miR-377-3p in Patients with DKD and the Regulatory Mechanism of miR-377-3p on the Inflammatory Response of HK-2 Cells Through TGF-β

Objective

The purpose of the study was to investigate the expression levels and correlation of inflammatory factors such as miR-377-3p and TGF-β in patients with diabetic kidney disease (DKD), and to investigate the regulatory mechanism of transfection of miR-377-3p on the inflammatory response of HK-2 cell induced by high glucose.

Methods

According to UACR, patients were divided into normal albuminuria group (Con, n = 29), microalbuminuria group (Micro, n = 31) and macroalbuminuria group (Macro, n = 30), analyzed the correlation and influencing factors between DKD and inflammatory factor. HK-2 cells were randomly divided into four groups: normal control group (NC), high glucose group (HG), miR-377-3p overexpression group (MIN), and miR-377-3p inhibition group (IN). After transfection of miR-377-3p mimics and inhibitors, the contents of TGF-β, IL-6 and IL-18 were detected by RT-PCR and Western blot.

Results

The levels of miR-377-3p, TGF-β, IL-6 and IL-18 in both Micro group and Macro group were significantly higher than those in Con group (P < 0.05); Pearson correlation analysis showed that miR-377-3p was positively correlated with UACR, TG, TGF-β, IL-6 and IL-18, and negatively correlated with GFR (P < 0.05). Cell experiment: RT-PCR and Western blot results showed that miR-377-3p, TGF-β, IL-6 and IL-18 in HG group were significantly higher than those in NC group (P < 0.05). After transfection with miR-377-3p inhibitor, the levels of miR-377-3p, TGF-β, IL-6 and IL-18 in IN group were significantly decreased compared with HG group and MIN group.

Conclusion

miR-377-3p expression was elevated both in serum of DKD patients and in HK-2 cells with high glucose induced injury, overexpression of miR-377-3p exacerbates the damage to HK-2 cells and promotes the progression of DKD. Silencing miR-377-3p can potentially regulate the levels of inflammatory factors in HK-2 cells by targeting downregulation of TGF-β expression, thereby mitigating the damage to HK-2 cells and delaying the development of diabetic kidney disease.

Vitamin D and chronic kidney disease: Insights on lipid metabolism of tubular epithelial cell and macrophages in tubulointerstitial fibrosis

Chronic kidney disease (CKD) has been recognized as a significant global health problem due to being an important contributor to morbidity and mortality. Inflammation is the critical event that leads to CKD development orchestrated by a complex interaction between renal parenchyma and immune cells. Particularly, the crosstalk between tubular epithelial cells (TECs) and macrophages is an example of the critical cell communication in the kidney that drives kidney fibrosis, a pathological feature in CKD. Metabolism dysregulation of TECs and macrophages can be a bridge that connects inflammation and fibrogenesis. Currently, some evidence has reported how cellular lipid disturbances can affect kidney disease and cause tubulointerstitial fibrosis highlighting the importance of investigating potential molecules that can restore metabolic parameters. Vitamin D (VitD) is a hormone naturally produced by mammalian cells in a coordinated manner by the skin, liver, and kidneys. VitD deficiency or insufficiency is prevalent in patients with CKD, and serum levels of VitD are inversely correlated with the degree of kidney inflammation and renal function. Proximal TECs and macrophages produce the active form of VitD, and both express the VitD receptor (VDR) that evidence the importance of this nutrient in regulating their functions. However, whether VitD signaling drives physiological and metabolism improvement of TECs and macrophages during kidney injury is an open issue to be debated. In this review, we brought to light VitD as an important metabolic modulator of lipid metabolism in TECs and macrophages. New scientific approaches targeting VitD e VDR signaling at the cellular metabolic level can provide a better comprehension of its role in renal physiology and CKD progression.

Urinary Exosomal MicroRNAs as Biomarkers for Obesity-Associated Chronic Kidney Disease

The early detection of chronic kidney disease (CKD) is key to reducing the burden of disease and rising costs of care. This need has spurred interest in finding new biomarkers for CKD. Ideal bi-omarkers for CKD should be: easy to measure; stable; reliably detected, even when interfering substances are present; site-specific based on the type of injury (tubules vs. glomeruli); and its changes in concentration should correlate with disease risk or outcome. Currently, no single can-didate biomarker fulfills these criteria effectively, and the mechanisms underlying kidney fibrosis are not fully understood; however, there is growing evidence in support of microRNA-mediated pro-cesses. Specifically, urinary exosomal microRNAs may serve as biomarkers for kidney fibrosis. In-creasing incidences of obesity and the recognition of obesity-associated CKD have increased interest in the interplay of obesity and CKD. In this review, we provide: (1) an overview of the current scope of CKD biomarkers within obese individuals to elucidate the genetic pathways unique to obesi-ty-related CKD; (2) a review of microRNA expression in obese individuals with kidney fibrosis in the presence of comorbidities, such as diabetes mellitus and hypertension; (3) a review of thera-peutic processes, such as diet and exercise, that may influence miR-expression in obesity-associated CKD; (4) a review of the technical aspects of urinary exosome isolation; and (5) future areas of research.