Project description:Patients with chronic kidney disease (CKD) are at markedly increased risk of disability, hospitalization, and death. Impaired physical function, which is common in CKD, is a major risk factor for these poor outcomes. CKD patients perform substantially below age-predicted norms on a variety of clinically relevant physical performance tests. Altered muscle physiology is an important cause of these functional deficits. We recently described skeletal muscle fibrosis in the vastus lateralis muscle of patients with severely impaired kidney function. Greater severity of fibrosis was associated with lower leg extension strength and reduced endurance capacity, suggesting that muscle fibrosis in CKD patients is functionally significant. An important unanswered question is whether muscle fibrosis in CKD is a slowly progressive process beginning with early loss of kidney function, or a complication observed only with severe disease. Here, we examined the associations of estimated glomerular filtration rate (a measure of kidney function) with measures of fibrosis across a broad range of kidney function, and tested the effect of receiving treatment with dialysis. We also integrated muscle transcriptomic analyses to provide further insight into this novel aspect of muscle pathology in CKD.
Project description:Skeletal muscle wasting is commonly associated with chronic kidney disease (CKD), resulting in increased morbidity and mortality. However, the link between kidney and muscle function remains poorly understood. Here, we took a complementary interorgan approach to investigate skeletal muscle wasting in CKD. We identified an increased production and elevated blood levels of soluble pro-cachectic factor Activin A, directly linking experimental and human CKD to skeletal muscle wasting programs. Single cell sequencing data identified the expression of Activin A in specific kidney cell populations, namely a subpopulation of fibroblasts and cells of the juxtaglomerular apparatus. Based on our findings, we propose that persistent and increased kidney production of pro-cachectic factors combined with a lack of kidney clearance facilitate a vicious signalling kidney-muscle cycle, leading to exacerbated blood accumulation of Activin A, and thereby skeletal muscle wasting in CKD.
Project description:Skeletal muscle wasting is commonly associated with chronic kidney disease (CKD), resulting in increased morbidity and mortality. However, the link between kidney and muscle function remains poorly understood. Here, we took a complementary interorgan approach to investigate skeletal muscle wasting in CKD. We identified an increased production and elevated blood levels of soluble pro-cachectic factor Activin A, directly linking experimental and human CKD to skeletal muscle wasting programs. Systemic pharmacological blockade of Activin A using soluble activin receptor type IIB ligand trap prevented muscle wasting in a mouse model of experimental CKD.
Project description:Cellular senescence is associated with the progression of chronic kidney disease (CKD), and accelerated tubular cell senescence promotes the pathogenesis of renal fibrosis. We established three animal models related to Chronic Kidney Disease, including aristolochic acid nephropathy (AAN), bilateral ischemia/reperfusion injury (BIRI) and unilateral ureter obstruction (UUO). By RNA sequencing analysis in AAN, BIRI and UUO mice, we observed significant changes of senescence and fibrosis related genes.
Project description:Chronic kidney disease (CKD) accelerates vascular calcification (VC) via phenotypic switching of vascular smooth muscle cells (VSMCs). We investigated the roles of circulating small extracellular vesicles (sEVs) between the kidneys and VSMCs and uncovered relevant sEV-propagated microRNAs (miRNAs) and their biological signaling pathways. We established CKD models in rats and mice by adenine-induced tubulointerstitial fibrosis. The miRNA transcriptome of sEVs revealed a depletion of several miRNAs in CKD. Their expression levels in sEVs from CKD patients were correlated to kidney function. This study revealed the transcriptomic landscape of miRNAs propagated in sEVs in CKD. We investigated the therapeutic potential of miRNAs in VC.
Project description:Incomplete repair after acute kidney injury (AKI) is associated with progressive loss of tubular cell function and development of chronic kidney disease (CKD). Here, we compared the kidney single-cell transcriptomes from the mice subjected to either unilateral ischemia-reperfusion kidney injury with contralateral nephrectomy (IRI/CL-NX, in which tubule repair predominates) or unilateral IRI with contralateral kidney intact (U-IRI, in which fibrosis and atrophy predominates) to investigate the mechanism(s) underlying transition to CKD following AKI.
Project description:Recent studies demonstrated that metabolic disturbance, such as augmented glycolysis, contributes to fibrosis. The molecular regulation of this metabolic perturbation in fibrosis, however, has been elusive. COUP-TFII (also known as NR2F2) is an important regulator of glucose and lipid metabolism. Its contribution to organ fibrosis is undefined. Here, we found increased COUP-TFII expression in myofibroblasts in human fibrotic kidneys, lungs, kidney organoids, and mouse kidneys after injury. Genetic ablation of COUP-TFII in mice resulted in attenuation of injury-induced kidney fibrosis. A non-biased proteomic study revealed the suppression of fatty acid oxidation and the enhancement of glycolysis pathways in COUP-TFII overexpressing fibroblasts. Overexpression of COUP-TFII in fibroblasts induced augmented glycolysis and production of alpha smooth muscle actin (αSMA) and collagen1. Knockout of COUP-TFII decreased glycolysis and collagen1 levels in fibroblasts. Chip-qPCR revealed the binding of COUP-TFII on the promoter of PGC1α. Overexpression of COUP-TFII reduced the cellular level of PGC1α. Targeting COUP-TFII serves as a novel treatment approach for mitigating fibrosis in chronic kidney disease and potentially fibrosis in other organs.