Project description:Kidney fibrosis, characterized by excessive extracellular matrix (ECM) deposition, is a progressive disease that, despite affecting 10% of the population, lacks specific treatments and suitable biomarkers. Aimed at unraveling disease mechanisms and identifying potential therapeutic targets, this study presents a comprehensive, time-resolved multi-omics analysis of kidney fibrosis using an in vitro model system based on human kidney PDGFRβ+ mesenchymal cells. Using computational network modeling we integrated transcriptomics, proteomics, phosphoproteomics, and secretomics with imaging of the extracellular matrix (ECM). We quantified over 14,000 biomolecules across seven time points following TGF-β stimulation, revealing distinct temporal patterns in the expression and activity of known and potential novel renal fibrosis markers and modulators. The resulting time-resolved multi-omic network models allowed us to propose mechanisms related to fibrosis progression through early transcriptional reprogramming. Using siRNA knockdowns and phenotypic assays, we validated predictions and elucidated regulatory mechanisms underlying kidney fibrosis. Notably, we demonstrate that several early-activated transcription factors, including FLI1 and E2F1, act as negative regulators of collagen deposition and propose underlying molecular mechanisms. This work advances our understanding of the pathogenesis of kidney fibrosis and provides a valuable resource for the organ fibrosis research community.
Project description:Aberrant proteolysis by cysteine cathepsins is implicated in carcinogenesis, but knowledge of cathepsin substrates mediating tumor-promoting or suppressing effects is limited. Here we characterize tumor proteome and in vivo cathepsin substrates using cathepsin knockout mice and the RIP1-Tag2 model of pancreatic islet carcinogenesis. Applying an unbiased systems-level proteomics approach, Terminal Amine Isotopic Labeling of Substrates (TAILS), we identified cysteine cathepsin B, H, L, S, Z substrates and their cleavage sites. Among 1,935 proteins and 1,114 N-termini identified by TAILS using 8-plex iTRAQ protein labeling, 145 neo-N-termini were significantly changed in one (55%) or more knockouts suggesting a lack of direct compensation at substrate level by other cathepsins. Most affected N-termini (56-83% for different cathepsins) represented degradative cathepsin activity, whereas 17-44% of neo-N termini represented stable proteolytic products in the tumors and were enriched for extracellular proteins. We identified candidate substrates for mediating signaling roles of cysteine cathepsins in tumorigenesis.
Project description:Secreted proteases act on interstitial tissue secretomes released from multiple cell types. Thus, substrate proteins might be part of higher molecular complexes constituted by many proteins with diverse and potentially unknown cellular origin. In cell culture these might be reconstituted by mixing native secretomes from different cell types prior to incubation with a test protease. Although current degradomics techniques could identify novel substrate proteins in these complexes, all information on the cellular origin would be lost. To address this limitation we combined iTRAQ-based Terminal Amine Isotopic Labeling of Substrates (iTRAQ-TAILS) with stable isotope labeling by amino acids in cell culture (SILAC) to assign proteins to a specific cell type by MS1- and their cleavage by MS2-based quantification in the same experiment. We demonstrate the power of our newly established workflow by monitoring matrix metalloproteinase (MMP) 10-dependent cleavages in mixtures from heavy labeled fibroblast and light labeled keratinocyte sectretomes. This analysis correctly assigned extracellular matrix components, such as laminins and collagens, to their respective cellular origins and revealed their processing in an MMP10-dependent manner. Hence, our newly devised degradomics workflow facilitates deeper insights into protease activity in complex intercellular compartments like the epidermal-dermal interface by integrating multiple modes of quantification with positional proteomics.
Project description:Mito-TAILS N-terminomics analysis of proteolytic events during EPEC infection of human epithelial cells, on whole-cell level and mitochondria.
Project description:The N-terminome in EBV-B cells from a human patient homozygous for an W580S mutation in MALT1 were analyzed by TMT10-plex TAILS and compared to EBV-B cells from heterozygous subjects under resting and PMA/ionomycin stimulation for 2 and 4 h.
Project description:We used TMT-TAILS to monitor MALT1 substrate cleavage in normal EBV B lymphocytes stimulated with PMA/ionomycin to evaluate kinetic profiles of MALT1 inhibitors
Project description:We developed a legumain inhibitor and activtiy based probes. Murine RAW264.7 cells were subjected to N-terminomics and shotgun proteomics analysis.
Project description:Dysregulated protease activity is often implicated in the initiation of inflammation and immune cell recruitment in gastrointestinal inflammatory diseases. Using N-terminomics/TAILS (terminal amine isotopic labeling of substrates), we compared proteases, along with their substrates and inhibitors, between colonic mucosal biopsies of healthy patients and those with ulcerative colitis (UC). Among the 1,642 N-termini enriched using TAILS, increased endogenous processing of proteins was identified in UC compared to healthy patients. Changes in the reactome pathways for proteins associated with metabolism, adherens junction proteins (E-cadherin, liver-intestinal cadherin, catenin alpha-1 and catenin delta-1) and neutrophil degranulation were identified between the two groups. Increased neutrophil infiltration and distinct proteases observed in ulcerative colitis may result in extensive break down, altered processing or increased remodeling of adherens junctions and other cellular functions. Analysis of the proteolytic preferred cleavage sites indicated that the majority of proteolytic activity and processing comes from host proteases, but that key microbial proteases may also play a role in maintaining homeostasis. Thus, the identification of distinct proteases and processing of their substrates improves the understanding of dysregulated proteolysis in normal intestinal physiology and ulcerative colitis.
Project description:Protease cleavage site preferences of LysargiNase (former name: ulilysin) and trypsin were tested using proteome-derived peptide libraries (Schilling et al Nature Protocols 2011)