WT1+ glomerular parietal epithelial progenitors promote renal proximal tubule regeneration after severe acute kidney injury

Zinc Deficiency Causes Glomerulosclerosis and Renal Interstitial Fibrosis Through Oxidative Stress and Increased Lactate Metabolism in Rats

Chronic kidney disease (CKD) is a highly prevalent condition characterized by renal fibrosis as its ultimate manifestation. Zinc deficiency is closely associated with CKD, evidenced by its link to renal fibrosis. Recently, local lactic acidosis has been demonstrated to promote renal fibrosis. Under zinc-deficient conditions, mitochondrial function is compromised and abnormal lactate metabolism might be induced potentially. However, it remains unclear whether zinc deficiency leads to renal fibrosis through local lactic acidosis. Zinc deficiency rat models were successfully established by feeding zinc-deficient diet. Western blot, qPCR, IHC, and other experiments were employed to investigate the key markers and molecular mechanisms of glomerulosclerosis and renal interstitial fibrosis. Our results indicate that zinc deficiency reduces specific markers of podocytes (podocalyxin, WT1, and nephrin) and activates the Wnt3a/β-catenin pathway, a key pathway in podocyte injury. Concurrently, glomerulosclerosis is indicated by increased urinary microalbumin and serum creatinine levels along with histological alteration observed through PAS and Masson staining in zinc-deficient rats. Furthermore, various degrees of upregulation for several markers of interstitial fibrosis including α-SMA, FN1 and collagen III are also revealed. These findings were further confirmed by Masson staining and IHC. Additionally, alterations in four markers in the EMT process, N-cadherin, E-cadherin, Vimentin, and snail, were consistent with expectations. We then confirmed the activation of the non-canonical TGF-β1 pathway known as the PI3K/AKT/mTOR pathway. An elevation in renal ROS levels accompanied by increased mitochondrial marker cytochrome C expression as well as an elevated NADH/NAD + ratio is also observed within the kidneys. Furthermore, the activity of both MMP/TIMP system and fibrinolytic system was abnormally enhanced under zinc deficiency conditions. Finally, we find zinc supplementation could significantly ameliorate relevant pathological alterations induced by zinc deficiency. These results collectively point that zinc deficiency causes podocyte damage ultimately resulting in glomerulosclerosis via accumulation of ROS and induces interstitial fibrosis via lactic acidosis.

Great potential of renal progenitor cells in kidney: From the development to clinic

The mammalian renal organ represents a pinnacle of complexity, housing functional filtering units known as nephrons. During embryogenesis, the depletion of niches containing renal progenitor cells (RPCs) and the subsequent incapacity of adult kidneys to generate new nephrons have prompted the formulation of protocols aimed at isolating residual RPCs from mature kidneys and inducing their generation from diverse cell sources, notably pluripotent stem cells. Recent strides in the realm of regenerative medicine and the repair of tissues using stem cells have unveiled critical signaling pathways essential for the maintenance and generation of human RPCs in vitro. These findings have ushered in a new era for exploring novel strategies for renal protection. The present investigation delves into potential transcription factors and signaling cascades implicated in the realm of renal progenitor cells, focusing on their protection and differentiation. The discourse herein elucidates contemporary research endeavors dedicated to the acquisition of progenitor cells, offering crucial insights into the developmental mechanisms of these cells within the renal milieu and paving the way for the formulation of innovative treatment modalities.