Advisor(s)
Jarrod Barnes
Committee Member(s)
John Chatham
Matthew Renfrow
Rakesh Patel
Stefanie Krick
Yan Sanders
School
Joint Health Sciences (Interdisciplinary)
Document Type
Dissertation
Department (new version)
Joint Health Sciences
Date of Award
9-16-2024
Abstract
Idiopathic pulmonary fibrosis (IPF) is a progressive, chronic lung disease that causes scarring of the lungs. IPF is often characterized by altered growth factor signaling, excessive extracellular matrix (ECM) deposition, fibroblast hyperproliferation, and dysregulated metabolism. The etiology of IPF is unknown, but fibroblasts and myofibroblasts are the known effector cells in IPF pathology. Current treatments, such as pirfenidone and nintedanib, target growth factor signaling pathways to slow fibrogenesis, but are unable to cure the disease. The transforming growth factor-beta (TGF-β) is a master regulator of fibrosis, including IPF, and is a powerful inducer of the fibroblast-to-myofibroblast transition (FMT). In IPF, metabolic reprogramming of myofibroblast is a pathological hallmark and better characterization of this process may provide insight into the development for therapeutics. The O-linked N-Acetylglucosamine (O-GlcNAc) transferase (OGT) is a glycosyltransferase responsible for the addition of the ‘GlcNAc’ sugar onto serines and threonines of proteins. OGT is documented as a metabolic sensor and has been reported to regulate TGF-β signaling, but to date, no studies have investigated the role of the OGT/O-GlcNAc axis in IPF prevention/resolution. To investigate the role of the OGT/O-GlcNAc axis in IPF prevention and resolution, we utilized a wide array of model systems (e.g. primary human lung fibroblasts [HLFs], HLF cell line, non-resolving aged mouse model, and Drosophila melanogaster). Data from a single-cell RNA sequence database and our in vivo/in vitro studies showed that the OGT/O-GlcNAc axis is upregulated in IPF. We investigated the evolutionary conserved roles of OGT in D. melanogaster and found that modulation of the OGT/O-GlcNAc axis regulated pericardin, a collagen-like protein. Knocking down OGT in a non-resolving mouse model of pulmonary fibrosis showed a resolution of collagen deposition and decreased Smad3 signaling. In HLFs, pharmacologically inducing hyper-O-GlcNAcylation using Thiamet G (TMG) or hypo-O-GlcNAcylation with OSMI-4 modulated the FMT as determined by levels of alpha-smooth muscle actin (α-SMA), and collagen types I and III, respectively. Smad3 was identified as a novel O-GlcNAcylated and modulating global O-GlcNAc levels in HLFs can decrease or increase phosphorylation levels, respectively. Further investigating the broad effects of OGT in TGF-β1 signaling, we utilized a kinomics platform to determine if other signaling pathways are impacted by OGT inhibition in HLFs. We found that p38 signaling is reduced with OGT inhibition, leading to an alteration of the phosphorylation kinetics of two proteins involved in IPF pathology, FOXO3 and NCF1 (p47phox). Taken together, these studies indicate a critical role for the OGT/O-GlcNAc axis in IPF pathogenesis, ECM resolution, and regulation of the TGF-β pathway. These new discoveries serve to broaden the horizon for finding new glycotherapeutics in IPF, or fibrosis, treatment.
ProQuest ID
Recommended Citation
Vang, Shia, "O-GlcNAc Transferase Regulates TGF-β Signaling and Fibrotic Resolution in Idiopathic Pulmonary Fibrosis" (2024). All ETDs from UAB. 7598.
https://digitalcommons.library.uab.edu/etd-collection/7598
