The glomerular circadian clock temporally regulates basement membrane dynamics and glucocorticoid response. Cultured podocyte cells circadian clock
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ABSTRACT: Kidney physiology has diurnal variation and abnormal circadian rhythm is associated with kidney disease. However, it is not known whether glomeruli, the filtering units in the kidney, are under circadian control. We therefore investigated core circadian clock components in cultered podocyte cells, together with their rhythmic targets and modes of regulation.
Project description:Nephrotic syndrome (NS) occurs when the glomerular filtration barrier becomes excessively permeable leading to massive proteinuria. In childhood NS, dysregulation of the immune system has been implicated and increasing evidence points to the central role of podocytes in the pathogenesis. Children with NS are typically treated with an empiric course of glucocorticoid (Gc) therapy; a class of steroids that are activating ligands for the glucocorticoid receptor (GR) transcription factor. Although Gc-therapy has been the cornerstone of NS management for decades, the mechanism of action, and target cell, remain poorly understood. We tested the hypothesis that Gc acts directly on the podocyte to produce clinically useful effects without involvement of the immune system. In human podocytes, we demonstrated that the basic GR-signalling mechanism is intact and that Gc induced an increase in podocyte barrier function. To gain mechanistic insight we performed RNA microarray and ChIP-sequencing and identified Gc regulation of motility genes.
Project description:A 45h time-course RNA-seq study was performed to analyse the different circadian phenotypes of human colorectal cancer cell line HCT116 WT, HCT116 ARNTL Knockout, HCT116 PER2 Knockout and HCT116 NR1D1 Knockout cells. Samples were taken every 3h starting from 9h after cell synchronization for a period of 45h resulting in 16 time-points for each cell line.
Project description:The circadian clock controls many aspects of physiology, but it remains undescribed whether extracellular vesicles (including exosomes) involved in cell-cell communications between tissues are regulated in a circadian pattern. We demonstrate a 24 h rhythmic abundance of individual proteins in exosomes using liquid chromatography-mass spectrometry in circadian-synchronised tendon fibroblasts. Further, the release of exosomes enriched in RNA-binding proteins was temporally separated from those enriched in cytoskeletal and matrix proteins, which peaked during the end of the light phase. Finally, we targeted the protein sorting mechanism in the exosome biogenesis pathway and established (by knockdown of circadian-regulated flotillin-1) that matrix metalloproteinase 14 abundance in tendon fibroblast exosomes is under flotillin-1 regulation. In conclusion, we have identified proteomic time signatures for exosomes released by tendon fibroblasts which supports the view that the circadian clock regulates protein cargo in exosomes involved in cell-cell crosstalk.
Project description:Purpose: Next-generation sequencing (NGS) was used to define the transcriptome of native mouse podocytes and non-podocytes glomerular cells as part of a project aiming to define the molecular fingerprint of mouse podocytes. Method: Glomeruli from 29 Gt(ROSA)26Sortm4(ACTB-tdTomato,-EGFP)Luo/J x hNPHS2Cre mice at the age of 10 weeks were purified and a single cell solution was prepared to seperate GFP-expressing (podocytes) and GFP-negative (non-podocytes glomerular cells) cells by FACS sorting. RNA was extracted and prepared for further analysis using directional, polyA+ library preparation. An Illumina HiSeq2500 was used for a paired-end sequencing of 100 cycles . Salmon and Sleuth were used for downstream analysis. Results: A total of 100 Million reads each from podocytes and non-podocytes glomerular cells could be used for further analysis.
Project description:Kidney physiology has diurnal variation and abnormal circadian rhythm is associated with kidney disease. However, it is not known whether glomeruli, the filtering units in the kidney, are under circadian control. We therefore investigated core circadian clock components in glomeruli, together with their rhythmic targets and modes of regulation.
Project description:Circadian clocks drive ~24 hr rhythms in tissue physiology. They rely on transcriptional/translational feedback loops driven by interacting networks of clock complexes.To gain insights into the role of the mammary clock, circadian time-series microarrays were performed to identify rhythmic genes in vivo. Breast tissues were isolated at 4 hr intervals for two circadian (24 hourly) cycles, from mice kept under constant darkness to avoid any light- or dark-driven genes.
Project description:We explored H3K27me3 binding sites in the genome of differentiated, conditionally immortalized mouse podocytes. Cells were allowed to differentiate for 14 days, following thermoshifting, before treatment with either vehicle (DMSO) or the S-adenosylhomocysteine hydrolase inhibitor 3-deazaneplanocin A (DZNep, 5µM for 48 hours) which degrades the histone methyltransferase, EZH2 ordinarily responsible for H3K27 trimethylation (H3K27me3). DNA was immunopreciptated with an H3K27me3-specific antibody. Studying H3K27me3 modification in Mouse Podocyte
Project description:Transcriptome analysis of growth hormone dependant genes in glomerular podocytes Differentiated human glomerular podocytes in culture exposed to growth hormone for 0 min, 2 min, 5 min, 15 min, and 30 min. Total RNA is extracted and subjected to microarray analysis.
Project description:Basement membranes (BMs) are ubiquitous extracellular matrices whose composition remains elusive, limiting our understanding of BM regulation and function. By developing a bioinformatic and in vivo discovery pipeline, we define a network of over 220 human proteins localized to BMs. More than 100 BM-network genes associate with human phenotypes and by screening over 63,000 germline genomic sequences from families with rare disorders, we discovered novel predicted loss-of-function variants in MATN2. Biochemical analyses suggest that MATN2 interacts with many BM proteins, and we found that depletion of MATN2 affected levels of core BM components in human podocyte-derived extracellular matrix.