Project description:Alport syndrome (AS) is a rare disease characterized by defective glomerular basement membranes, caused by mutations in COL4A3, COL4A4 and COL4A5, which synthesize collagen type IV. Patients present with progressive proteinuria, hematuria and podocyte loss. There is currently no cure for AS, and this is mainly due to its complex and variable pathogenesis, as well as the lack of models that can faithfully mimic the human phenotype.
Project description:Alport syndrome is a glomerular disease. To understand the disease progression of alport syndrome and potential therapeutical effects of hEV derived from AFSCs, we performed spatial transcriptomics to profile the heterogeniety of cell populations in kidneys of mouse of AS through disease progression and hEV treated AS mice as well. Our analysis sheds light on key functional parts of the kidney responsible in disease progression as well as potential targets of hEV therapy.
Project description:In study we investigated podocyte maturation, with a particular focus on type IV collagen maturation in the glomerular basement membrane (GBM) of kidney organoids over extended culture periods (comparing Control Organoid d22 R2 with Control Organoid d38). The secondary aim was to compare the gene expression profiles of podocytes in X-linked Alport syndrome (XLAS) organoid models with isogenic controls at an early culture time point (day 22). Two distinct batches of sample collection were conducted to capture early and later stages of GBM development. In the first batch, three libraries were generated by collecting 16 organoids from one isogenic control, one severe XLAS model, and one moderate XLAS model on day 22 of differentiation. In the second batch, two libraries were created to evaluate the impact of culture duration on GBM maturation by harvesting an additional isogenic control organoid at both day 22 and day 38 of culture. Organoids were dissociated using a two-step enzymatic and mechanical protocol to obtain single-cell suspensions, with cell viability ranging between 70% and 85%. This experimental design enabled a comparative analysis of GBM maturation dynamics between early and late time points and across different severities of XLAS. Findings from this study provided insights into the cellular mechanisms underlying GBM abnormalities in Alport syndrome and supported the potential for GBM maturation in kidney organoids over time.
Project description:Background: Renal lipid dysmetabolism contributes to glomerular disease progression, including Alport Syndrome. We recently identified alterations in the apolipoprotein M/sphingosine-1-phosphate/sphingosine-1-phosphate receptor 4 signaling axis in glomeruli from patients with glomerular disease. Methods: We utilized Col4a3 knockout mice and immortalized podocytes derived from these mice as a mouse model of Alport Syndrome. Mice and podocytes were treated with recombinant apolipoprotein M or the sphingosine-1-phosphate receptor 4 antagonist, CYM50358. Results: Col4a3-/- glomeruli and podocytes exhibited reduced apolipoprotein M and increased sphingosine-1-phosphate receptor 4 expression and increased sphignsoine-1-phosphate levels, mirroring findings in patients with glomerular disease. Treatment with apolipoprotein M or CYM50358 reduced albuminuria, BUN, and plasma creatinine, and ameliorated glomerulosclerosis, tubulointerstitial fibrosis, podocyte loss and foot process effacement. Both treatments reduced triglyceride and cholesterol accumulation in glomeruli and podocytes. RNA-seq analysis of Col4a3-/- revealed that sphingosine-1-phosphate receptor 4 antagonism upregulated lysosomal and autophagy-related genes. Western blot analysis confirmed increased LC3-II/LC3-I ratios and decreased p62, indicating enhanced autophagic flux. Treated podocytes showed increased lysosome numbers and co-localization with lipid droplets. In contrast, apolipoprotein M had no effect on autophagy but promoted cholesterol efflux. Conclusions: The apolipoprotein M/sphingosine-1-phosphate axis is dysregulated in Col4a3-/- podocytes. Targeting this pathway through apolipoprotein M supplementation or sphingosine-1-phosphate receptor 4 antagonism improves renal function and reduces lipid accumulation by enhancing either cholesterol efflux or autophagy, respectively. These findings suggest that restoring lipid homeostasis via targeting the APOM/S1P/S1PR4 axis may be a promising therapeutic strategy for Alport Syndrome and other glomerular diseases.
Project description:Alport syndrome (AS) is a hereditary glomerulonephritis caused by COL4A3, COL4A4 or COL4A5 gene mutations and characterized by abnormalities of glomerular basement membranes (GBMs). Due to a lack of curative treatments, the condition proceeds to end-stage renal disease even in adolescents. Hampering drug discovery is the absence of effective in vitro methods for testing the restoration of normal GBMs. Here, we aimed to develop kidney organoid models from AS patient iPSCs for this purpose. We established iPSC-derived collagen α5(IV)-expressing kidney organoids and confirmed that kidney organoids from COL4A5 mutation-corrected iPSCs restore collagen α5(IV) protein expression. Importantly, our model recapitulates the differences in collagen composition between iPSC-derived kidney organoids from mild and severe AS cases. Furthermore, we demonstrate that a chemical chaperone, 4-phenyl butyric acid, has the potential to correct GBM abnormalities in kidney organoids showing mild AS phenotypes. This iPSC-derived kidney organoid model will contribute to drug discovery for AS.
Project description:Purpose: MicroRNA-21 contributes to the pathogenesis of fibrogenic diseases in multiple organs including the kidney. To evaluate the therapeutic utility of antimiR-21 oligonucleotides in chronic kidney disease, we silenced miR-21 in mice that develop Alport Nephropathy due to a defect in the Col4a3 gene. The goals of this study to assess the effect of inhibiting miR-21 in the Col4a3-/- Alport Syndrome mouse model at 9 weeks of age. Methods: Col4a3-/-, Col4a3+/-, and Col4a3+/+ mice in the 129X1/SvJ genetic background were obtained. Mice received anti–miR-21 (25 mg/kg) or control anti-miR (25mg/kg) in phosphate-buffered saline (PBS) by inter-scapular subcutaneous injection twice per week. In some experiments mice received a range of doses from 12.5mg/kg once a week to 50mg/kg once a week. Anti–miR-21 is a high-affinity oligonucleotide complementary to the active site of miR-21. Mice received injections starting at 24 days (3.5 weeks) after birth and ending at 5, 7, 9 or 16 weeks after birth depending on the study objectives. Total RNA from kidney tissue was extracted as per manufacturer’s instructions (miREASY kit, Qiagen). RNA quality was assessed using BioAnalyzer (Agilent). mRNA expression profiles were determined using next-generation sequencing (NGS) on the Illumina HiSeq 2000 platform producing 50bp paired-end reads. Bowtie/TopHat suites were used to align the reads to mouse genome or transcriptome and RSEM were used to quantify gene abundances. Gene level counts were then normalized with the R/Bioconductor package limma using the voom/variance stabilization method. Results: Anti-miR-21 enhanced PPAR?/RXR activity and associated downstream signaling pathways in glomerular, tubular and interstitial cells, enhanced mitochondrial function, which reduced mitochondrial ROS production and preserved tubular cell functions. In addition, inhibition of miR-21 reduced fibrogenic and inflammatory signaling in glomerular and interstitial cells, likely as a consequence of enhanced PPAR?/RXR activity and mitochondrial function. Inhibition of miR-21 represents a novel therapeutic strategy for chronic kidney diseases including Alport Nephropathy. Whole kidney mRNA profiles of wild type and Col4a3-/- mice treated with either PBS or antimiR-21, ending at 9 weeks of age, were generated by Next Generation Sequencing in triplicate using Illumina HiSeq 2000
Project description:Purpose: MicroRNA-21 contributes to the pathogenesis of fibrogenic diseases in multiple organs including the kidney. To evaluate the therapeutic utility of antimiR-21 oligonucleotides in chronic kidney disease, we silenced miR-21 in mice that develop Alport Nephropathy due to a defect in the Col4a3 gene. The goals of this study to assess the effect of inhibiting miR-21 in the Col4a3-/- Alport Syndrome mouse model at 5.5 weeks of age. Methods: Col4a3-/-, Col4a3+/-, and Col4a3+/+ mice in the 129X1/SvJ genetic background were obtained. Mice received anti–miR-21 (25 mg/kg) or control anti-miR (25mg/kg) in phosphate-buffered saline (PBS) by inter-scapular subcutaneous injection twice per week. In some experiments mice received a range of doses from 12.5mg/kg once a week to 50mg/kg once a week. Anti–miR-21 is a high-affinity oligonucleotide complementary to the active site of miR-21. Mice received injections starting at 24 days (3.5 weeks) after birth and ending at 5, 7, 9 or 16 weeks after birth depending on the study objectives. Total RNA from kidney tissue was extracted as per manufacturerâs instructions (miREASY kit, Qiagen). RNA quality was assessed using BioAnalyzer (Agilent). mRNA expression profiles were determined using next-generation sequencing (NGS) on the Illumina HiSeq 2000 platform producing 50bp paired-end reads. Bowtie/TopHat suites were used to align the reads to mouse genome or transcriptome and RSEM were used to quantify gene abundances. Gene level counts were then normalized with the R/Bioconductor package limma using the voom/variance stabilization method. Results: Anti-miR-21 enhanced PPARα/RXR activity and associated downstream signaling pathways in glomerular, tubular and interstitial cells, enhanced mitochondrial function, which reduced mitochondrial ROS production and preserved tubular cell functions. In addition, inhibition of miR-21 reduced fibrogenic and inflammatory signaling in glomerular and interstitial cells, likely as a consequence of enhanced PPARα/RXR activity and mitochondrial function. Inhibition of miR-21 represents a novel therapeutic strategy for chronic kidney diseases including Alport Nephropathy. Whole kidney mRNA profiles of Col4a3+/- (triplicate) and Col4a3-/- (quadruplicates) mice treated with either PBS or antimiR-21, ending at 5.5 weeks of age, were generated by Next Generation Sequencing using Illumina HiSeq 2000