Dataset Information

Intestinal Differentiation Involves Cleavage of Histone H3 NTerminal Tails by Multiple Proteases

ABSTRACT: The proteolytic cleavage of histone tails, also termed histone clipping, has been described as a mechanism for permanent removal of post-translational modifications (PTMs) from histone proteins. Such activity has been ascribed to ensure regulatory function in key cellular processes such as differentiation, senescence and transcriptional control for which different histone-specific proteases has been described. However, all these studies were exclusively performed using cell lines cultured in vitro and no clear evidences that histone clipping is regulated in vivo has been reported. Here we show that histone H3 N-terminal tails undergo extensive cleavage in the differentiated cells of the villi fraction of the mouse intestinal epithelium. Combining biochemical methods, 3D organoids cultures and in vivo approaches, we demonstrate that intestinal H3 clipping is the result of multiple proteolytic activities. We identified Trypsins and Cathepsin L as specific H3 tail proteases active in small intestinal differentiated cells and showed that their proteolytic activity is differentially affected by the PTM pattern of histone H3 tails. Together, our findings provide in vivo evidences of H3 tail proteolysis in mammalian tissues directly linking H3 clipping to cell differentiation.

ORGANISM(S): Mus musculus

PROVIDER: GSE160776 | GEO | 2020/12/04

REPOSITORIES: GEO

ACCESS DATA

Dataset's files

Source:

			Action	DRS
		Other

Items per page:

1 - 1 of 1

Similar Datasets

Project description:Hypoxia in stem cell niches and inner core of solid tumors contributes to cellular senescence and differentiation inhibition. It directly increases histone methylationby inhibiting the activities of O2-and α-ketoglutarate (α-KG)-dependent histone lysine demethylases. This study is the first to demonstrate how the hypoxic increment of methylated histones cross-talks with other epigenetic changes, such as histone clipping and heterochromatin redistribution, named senescence-associated heterochromatin foci (SAHF), which are found during oncogene-induced senescence (OIS). This study showed that Raf activation in primary human fibroblasts IMR90 increases mature cathepsin L (CTSL)-mediated cleavage of H3, H2B, and H4. Hypoxia prevented H3 cleavage not by inhibiting CTSL but by increasing H3K18me3 and H3K23me3 nearby cleaved site of H3. Forced expression of cleaved H3 in IMR90 cells induced senescence even under hypoxia, suggesting that hypoxia breaks this positive feedback senescence driving circle by increasing methylated histones. The decrease in methylated histones is necessary for OIS to trigger histone clipping and SAHFs, but hypoxia maintains methylated histones to prevent both. Forced reduction of methylated histones in hypoxic cells using inhibitors of methyl-transferases makes hypoxic conditions unable to prevent OIS from inducing both histone clipping and SAHFs. Reversely forced enhancement of methylated histones in normoxic cells using inhibitors of histone demethylases protected histones from clipping during OIS but failed to block SAHFs. Altogether, the maintenance of methylated histones, especially H3K23me3 and H3K18me3, is sufficient to protect histones from clipping during OIS, but not for inhibiting SAHFs, suggesting that besides inhibiting KDMs, hypoxia adopts other methods to inhibit SAHFs. These findings provide a novel mechanism by which hypoxia affects cell fate by increasing methylated histones that protect histones and chromatin from dramatic epigenetic changes.

Project description:The N-terminal regions of histone proteins (histone tails) are dynamic elements that protrude from the nucleosome and are involved in many aspects of chromatin organization. Their epigenetic role is well-established, and post-translational modifications present on these regions contribute to transcriptional regulation. Considering their biological significance, relatively few structural details have been established for histone tails, mainly due to their inherently disordered nature. While hydrogen/deuterium exchange mass spectrometry (HX-MS) is well-suited for the analysis of dynamic structures, it has seldom been employed in this context, presumably due to the poor N-terminal coverage provided by pepsin, the dominant protease in HX-MS studies. Inspired from histone-clipping events, we profiled the activity of Cathepsin-L under HX-MS quench conditions and characterized its specificity employing the four core histones (H2A, H2B, H3 and H4). Cathepsin-L demonstrated cleavage patterns that were substrate- and pH-dependent and showed optimum activity in a slightly reducing and non-denaturing environment. Cathepsin-L generated overlapping N-terminal peptides about 20 amino acids long for H2A, H3 and H4 proving its suitability for the analysis of histone tails dynamics. We developed a comprehensive HX-MS method in combination with pepsin and obtained full sequence coverage for all histones. We employed our method to analyze histones H3 and H4. We observe rapid deuterium exchange of the N-terminal tails and cooperative unfolding (EX1 kinetics) in the histone-fold domains of histone monomers in-solution. When in a mononucleosome, we find evidence for inter- or intramolecular interactions within the H4 tail but not for H3.1. Further, EX1 kinetics observed in the respective monomers are absent when in the mononucleosome, indicating stabilization of the histone-folds. The data obtained here may serve as a baseline towards the comparison of nucleosome dynamics harboring different histone variants or post-translational modifications. Overall, this novel strategy opens new avenues for investigating the dynamic properties of histones and nucleosomes that are not apparent from the crystal structures, providing insights into the structural basis of the histone code.

Project description:Proteases constitute the largest enzyme gene family in vertebrates with intracellular and secreted proteases having critical roles in cellular and organ physiology. Intestinal tract contains diverse set of proteases mediating digestion, microbial responses, epithelial and immune signaling. Transit of chyme through the intestinal tract results in significant suppression of proteases. Although endogenous protease inhibitors have been identified, the broader mechanisms underlying protease regulation in the intestinal tract remains unclear. The objective of this study was to determine microbial regulation of proteolytic activity in intestinal tract using phenotype of post-infection irritable bowel syndrome, a condition characterized by high fecal proteolytic activity. Proteases of host pancreatic origin (chymotrypsin like pancreatic elastase 2A, 3B and trypsin 2) drove proteolytic activity. Of the 14 differentially abundant taxa, high proteolytic activity state was characterized by complete absence of the commensal Alistipes putredinis. Germ free mice had very high proteolytic activity (10-fold of specific-pathogen free mice) which dropped significantly upon humanization with microbiota from healthy volunteers. In contrast, high proteolytic activity microbiota failed to inhibit it, a defect that corrected with fecal microbiota transplant as well as addition of A. putredinis. These mice also had increased intestinal permeability similar to that seen in patients. Microbiota β-glucuronidases mediate bilirubin deconjugation and unconjugated bilirubin is an inhibitor of serine proteases. We found that high proteolytic activity patients had lower urobilinogen levels, a product of bilirubin deconjugation. Mice colonized with β-glucuronidase overexpressing E. coli demonstrated significant inhibition of proteolytic activity and treatment with β-glucuronidase inhibitors increased it. The findings establish that specific commensal microbiota mediates effective inhibition of host pancreatic proteases and maintains intestinal barrier function through the production of β-glucuronidases. This suggests an important homeostatic role for commensal intestinal microbiota.

Dataset Information

Intestinal Differentiation Involves Cleavage of Histone H3 NTerminal Tails by Multiple Proteases

Dataset's files

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets