Mechanical Regulation of Adipose TissueFibrosis and Metabolic Disease

PROJECT SUMMARY/ABSTRACT Adipose tissue fibrosis is an irreversible disorder associated with obesity-related conditions, including type 2 diabetes, non-alcoholic fatty liver disease, and cardiovascular disease. Adipocytes within white adipose tissue (WAT) are surrounded by an extracellular matrix (ECM) whose composition and remodeling are of crucial importance in modulating mechanotransduction pathways – pathways by which cells sense and respond to their environment - that control cell fate. During obesity, aberrant WAT expansion can induce physical constraints on adipocytes, triggering an inflammatory response, disrupting lipolysis, and reducing insulin sensitivity, impairing WAT's ability to regulate energy balance. To address the complex role of adipose tissue dysfunction in metabolic disease, this project aims to uncover the early mechanisms driving adipose tissue fibrosis and its influence on metabolic disease, thus guiding the development of targeted therapies. Previous in vitro studies have determined that the ECM protein, aortic carboxypeptidase-like protein (ACLP), enhances pro-fibrotic, anti- adipogenic pathways through transforming growth factor β (TGFβ) receptor signaling. My preliminary data supports ACLP-dependent activation of integrin-mediated GTPase signaling and cytoskeleton remodeling potentially through its interactions in the ECM. The collagen-binding discoidin domain of ACLP activates adipocyte progenitor differentiation and enhances cell spreading independent of TGFβ signaling, suggesting an domain-dependent role in fibrotic mechanical signaling. However, the specific pathways by which ACLP activates mechanotransduction in adipose tissue to induce fibrotic remodeling remains unknown. We hypothesize that obesity-induced ACLP secretion in the ECM of WAT induces a profibrotic, anti-adipogenic phenotype through integrin-mediated mechanotransduction, contributing to metabolic disease. To investigate these underlying mechanisms, we will employ a combination of biomechanical techniques, in vitro assays, and in vivo models. Aim 1 will delineate the pathways by which ACLP regulates mechanotransduction in the ECM, employing biomechanical measures and in vitro assays to characterize mechanotransduction pathways in mouse stromal vascular progenitor cells and adipose explants. Aim 2 will investigate the role of ACLP in diet-induced obesity, adipose tissue fibrosis, and metabolic disease in vivo using an ACLP loss-of-function mouse model, combined with single-cell RNA sequencing to identify progenitor population changes caused by ACLP loss-of-function. These studies will provide a comprehensive evaluation of the mechanotransduction pathways regulated by ACLP, highlighting potential targets for future therapeutics in combating adipose tissue fibrosis and metabolic disease. Moreover, my proposed plan will provide diverse training in cellular biology, bioinformatics, and biomedical engineering, equipping me with the skills necessary for success as an independent research scientist.