Project description:Metzincins and related genes (MARGS) play important roles in ECM remodeling in fibrotic conditions. In this investigation, gene expression was examined in a rat model to investigate whether the previously described MARGS based fibrosis classifier had diagnostic value in an experimental rat model of lithium-induced renal fibrosis
Project description:Histologic findings on 1-year biopsies such as inflammation with fibrosis and transplant glomerulopathy predict renal allograft loss by 5 years. However, almost half of the patients with graft loss have a 1-year biopsy that is either normal or has only interstitial fibrosis. The goal of this study was to determine if there was a gene expression profile in these relatively normal 1-year biopsies that predicted subsequent decline in renal function. Using transcriptome microarrays we measured intragraft mRNA levels in a retrospective Discovery cohort (170 patients with a normal/minimal fibrosis 1-year biopsy, 54 with progressive decline in function/graft loss and 116 with stable function) and developed a nested 10-fold cross-validated gene classifier that predicted progressive decline in renal function (positive predictive value=38±34%%; negative predictive value=73±30%, c-statistic=0.59). In a prospective, multicenter Validation cohort (270 patients with Normal/Interstitial Fibrosis [IF]), the classifier had a 20% positive predictive value, 85% negative predictive value and 0.58 c-statistic. Importantly, the majority of patients with graft loss in the prospective study had 1-year biopsies scored as Normal or IF. We conclude predicting graft loss in many renal allograft recipients (i.e. those with a relatively normal 1-year biopsy and eGFR >40) remains difficult.
Project description:Crosstalk of renal epithelial cells with interstitial fibroblasts plays an important role in kidney pathophysiology. A former study showed that crosstalk between renal epithelial cells and renal fibroblasts protects against acidosis-induced damage. In order to gain further mechanistic insight into this crosstalk we investigated the effect of acidosis on the transcriptome of renal epithelial cells (NRK-52E) and renal fibroblasts (NRK-49F) in co-culture by RNASeq, bioinformatics analysis and experimental validation.
Project description:Chronic kidney disease is associated with progressive renal fibrosis, where perivascular cells give rise to the majority of α-SMA positive myofibroblasts. We sought to identify pericytic miRNAs that could serve as a target to decrease myofibroblast formation. We induced kidney fibrosis in FoxD1-GC;Z/Red-mice by unilateral ureteral obstruction (UUO) followed by FACS sorting of dsRed-positive FoxD1-derivative cells and miRNA profiling. MiR-132 selectively increased 21-fold during pericyte-to-myofibroblast formation whereas miR-132 was only 2.5-fold up in total kidney lysates (both in UUO and ischemia-reperfusion injury). MiR-132 silencing in UUO decreased collagen deposition (35%) and tubular apoptosis. Immunohistochemistry, western blot and qRT-PCR confirmed a similar decrease in interstitial α-SMA+ cells. Pathway analysis identified a rate-limiting role for miR-132 in myofibroblast proliferation that was confirmed in vitro. Indeed, antagomir-132 treated mice displayed a reduction in the number of proliferating, ki67+ interstitial myofibroblasts. Interestingly, this was selective for the interstitial compartment and did not impair the reparative proliferation of tubular epithelial cells, as evidenced by an increase in ki67+ epithelial cells, as well as increased (p-)RB1, Cyclin-A and decreased RASA1, p21 levels in kidney lysates. Taken together, silencing miR-132 counteracts the progression of renal fibrosis by selectively decreasing myofibroblast proliferation and could potentially serve as a novel antifibrotic therapy. Total RNA obtained from FACS sorted mouse renal FoxD1-derivatve interstitial cells from mice that were treated with antagomir-132 or scramblemir and underwent UUO (n=4)
Project description:Chronic kidney disease (CKD) is a burden for Public Health and concerns millions of individuals worldwide. Independently of the cause, CKD is secondary to the replacement of functional renal tissue by extra-cellular matrix proteins (i.e fibrosis) that progressively impairs kidney function. The pathophysiological pathways that control the development of renal fibrosis are common to most of the nephropathies involving native kidneys or kidney grafts. Unfortunately, very few treatments are available to stop renal fibrosis and most of the therapeutic strategies are often barely able to slow down the progression of fibrogenesis in native kidneys. Therefore, it is mandatory to discover new therapeutic pathways to stop renal fibrosis. Our objective is to study new pathways involved in renal fibrosis. We thus decided to use the model of Unilateral Ureteral renal Obstruction in mice, a fast and reproducible experimental model of renal fibrosis. We studied renal fibrosis using experimental model of ureteral unilateral obstruction in mice, which was performed by complete ligation of the left ureter. The control lateral right kidney served as internal control.
Project description:Chronic kidney disease is associated with progressive renal fibrosis, where perivascular cells give rise to the majority of α-SMA positive myofibroblasts. We sought to identify pericytic miRNAs that could serve as a target to decrease myofibroblast formation. We induced kidney fibrosis in FoxD1-GC;Z/Red-mice by unilateral ureteral obstruction (UUO) followed by FACS sorting of dsRed-positive FoxD1-derivative cells and miRNA profiling. MiR-132 selectively increased 21-fold during pericyte-to-myofibroblast formation whereas miR-132 was only 2.5-fold up in total kidney lysates (both in UUO and ischemia-reperfusion injury). MiR-132 silencing in UUO decreased collagen deposition (35%) and tubular apoptosis. Immunohistochemistry, western blot and qRT-PCR confirmed a similar decrease in interstitial α-SMA+ cells. Pathway analysis identified a rate-limiting role for miR-132 in myofibroblast proliferation that was confirmed in vitro. Indeed, antagomir-132 treated mice displayed a reduction in the number of proliferating, ki67+ interstitial myofibroblasts. Interestingly, this was selective for the interstitial compartment and did not impair the reparative proliferation of tubular epithelial cells, as evidenced by an increase in ki67+ epithelial cells, as well as increased (p-)RB1, Cyclin-A and decreased RASA1, p21 levels in kidney lysates. Taken together, silencing miR-132 counteracts the progression of renal fibrosis by selectively decreasing myofibroblast proliferation and could potentially serve as a novel antifibrotic therapy. Total RNA obtained from FACS sorted mouse FoxD1-derivative interstitial cells from healthy or fibrotic kidneys
Project description:Inflammation is a key component of fibrosis, however, the immune processes that orchestrate kidney fibrosis are poorly understood. By performing single-cell sequencing of a mouse model of kidney fibrosis, we identified a subset of kidney tubule cells with a profibrotic-inflammatory phenotype, characterized by the expression of cytokines and chemokines associated with immune cell recruitment. Receptor-ligand interaction analysis and experimental validation indicated that CXCL1 secreted by profibrotic tubules recruits CXCR2+ basophils. In mice, these basophils were the key source of IL-6 and were responsible for the recruitment of Th17 cells. Genetic deletion or antibody-based depletion of basophils resulted in reduced renal fibrosis. Human kidney single-cell, bulk gene expression, and immunostaining results validated the role of basophils in patients with kidney fibrosis. Collectively, these studies identify basophils as key contributors to the development of renal fibrosis and suggest that targeting these cells may be a useful strategy for the management of chronic kidney disease.
Project description:Renal tubular atrophy and interstitial fibrosis are common hallmarks of etiologically different progressive chronic kidney diseases (CKD) that eventually result in organ failure. We identify Dickkopf-3 (Dkk3) as a stress-induced, tubular epithelia-derived mediator of kidney fibrosis. Genetic as well as antibody-mediated abrogation of Dkk3 led to reduced tubular atrophy and decreased interstitial matrix accumulation in two mouse models of renal fibrosis. This was accompanied by an amplified, anti-fibrogenic, inflammatory response within the injured kidney. Mechanistically, Dkk3 deficiency led to diminished canonical Wnt/β-catenin signaling in stressed tubular epithelial cells. To identify global changes in gene expression due to the lack of Dkk3, whole-transcriptome sequencing (mRNA-seq) was performed on RNA isolated from kidneys of Wt and Dkk3-/- mice 7 days after UUO.