Analyse du matrisome gastrique utilisant un modèle murin avec la signalisation de BMP défectueuse dans les télocytes
Year: 2021
Type: dissertation
Abstract: The extracellular matrix (ECM) is a dynamic structure that induces several signaling pathways which influence the behavior of epithelial cells. Telocytes (TC) are novel subepithelial cells that form a central communication axis between the stroma and the epithelium. TC are bioactive and secrete growth factors and ECM proteins that form the microenvironment surrounding the epithelium. In recent years, we have demonstrated that the alteration of BMP (bone morphogenetic protein) signaling in TC triggers a toxic microenvironment with ECM remodeling that leads to the development of preneoplastic gastric lesions. However, a comprehensive analysis of variations in the composition of the ECM and its associated proteins in gastric neoplasia associated with TC dysregulation has never been performed. This work aims to understand how TC defective in BMP signaling participates in an aberrant gastric preneoplastic microenvironment. For this, a proteomic approach was used to determine the global changes in the complete matrisome in the stomach of 90-day-old Bmpr1aΔFoxl1 mice and control mice. Immunofluorescence (IF) and western blot were performed to validate some of the proteins identified by proteomics. In addition, Sirius red staining were performed on stomach sections to analyze collagen (CL) dysregulations. The alteration of BMP signaling in TC led to dysregulations of the expression of matrisome proteins in all its categories (CL, proteoglycans, glycoproteins, ECM-affiliated proteins, ECM-regulators, and secreted factors). The proteomic analysis showed a downregulation of practically all the detected CL chains and for almost all proteoglycans. However, the qualitative analysis of CL deposition by Sirius red staining using polarized light microscopy revealed a strong deposition of CL, with a significant realignment of its fibers, suggesting changes in tissue biodynamics. Compared to control, mutant mice showed upregulation of ECM glycoproteins related to the basement membrane and proliferation such as FN1, TNC and SPARC was observed, as well as a down regulation of MFAP2, Nid1 and 2 and the tumor suppressor gene SPARCL-1, associated with the alteration of elastic fibers and adhesion. Our analysis showed upregulation of ECM remodeling and degradation proteins such as cathepsin E, along with ADAM9 involved in cell motility and known to promote gastric cancer. Finally, among the matrisome-associated proteins, ECM-regulators such as ADMA9 involved in cell proliferation were found to be overexpressed. Also, various secreted factors such as a CAF (cancer associated fibroblast) marker S100A4, and S100A8 and A9 related to signs of inflation. This approach, used with our gastric preneoplastic mouse model, provides a detailed inventory of the core-matrisome and matrisome-associated proteins, such as ECM remodeling enzymes and other secreted factors. This allows us to identify important and subtle changes in the biology of the ECM that occur during the etiology of gastric neoplasia associated with defective TC in BMP signaling.
Author: Alfonso Chaviano, Alain Bárbaro
Language: English
Topic: TGF-β signaling in diseases
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W7201924475