Role of Protein S-Palmitoylation in TGFbeta Signaling and Fibrotic Lung Disease

PROJECT SUMMARY / ABSTRACT Idiopathic pulmonary fibrosis (IPF) is a highly fatal disease characterized by irreversible destruction of lung tissue and a median survival well below 5 years. The pathologic effector cells in IPF are collagen-secreting fibroblasts driven by transforming growth factor beta (TGF-β). Despite the promise of TGF-β inhibition as a treatment for pulmonary fibrosis, global blockade has been associated with severe side effects, necessitating the identification of strategic therapeutic targets within this pathway. Harnessing the candidate's formal training in biochemistry and innovative expertise in protein post-translational modifications, proteomics, and machine learning, a previously unknown site of lipid modification (S-palmitoylation) on the TGF-β receptor (TGFβR1) has been discovered that appears to regulate its activity. Additionally, evidence of global S-palmitoyl perturbation in IPF has been identified. Based on preliminary data, the candidate hypothesizes that S- palmitoylation of the TGFβR1 receptor represents a reversible pro-fibrotic regulatory mechanism, whose enzymatic regulators may represent novel anti-fibrotic targets. The proposal’s three aims interrogate the roles of S-palmitoylation at three distinct levels: molecular, cellular, and regulatory. Aim 1 utilizes cultured fibroblasts to probe the molecular implications of S-palmitoylation on ligand-induced TGFβR1 phosphorylation and immediate effectors such as Smads, MAP and Src kinase. Aim 2 uses adeno-associated viral (AAV)-based fibroblast expression of TGFβR1 to examine the role(s) of S-palmitoylation within two distinct fibrotic mouse models. Finally, Aim 3 utilizes AAV-based CRISPR deletion to investigate the fibrotic contributions of two enzymatic S-palmitoyl regulators – palmitoyl transferase Dhhc20 and depalmitoylase Abhd17a – that are selectively induced in pathologic fibroblasts and may represent novel antifibrotic targets. These aims allow for the candidate's skill development in cell biology and animal models, while simultaneously supporting a career development plan that fosters expertise in AAV tools, quantitative microscopy, flow cytometry, mouse handling, and advanced bioinformatics. The proposed aims and training plan will delineate the role(s) of S-palmitoylation in IPF and potentially generate a novel therapeutic angle to target pathologic fibroblast signaling and reduce fibrosis. The mentorship team, led by Dr. Purushothama Rao Tata, includes experts in lung biology, fibrosis, TGF-β signaling, and proteomics, ensuring comprehensive training and guidance throughout the award period. This K08 award will pave the road toward the candidate's overarching career goal of anti-fibrotic discovery by focusing on fibrosis-oriented post-translational protein modifications, ultimately aiming to improve outcomes for patients with IPF and other fibrotic lung diseases.