SOCS domain-mediated fibronectin matrix degradation on fibrosis reversal

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ABSTRACT Idiopathic Pulmonary fibrosis (IPF) is an irreversible lung disease with no effective treatment options. Insurance claims data on IPF incidence between years 2001-2011 was estimated at 31-43 per 100,000 per year, translating to 89,000 patients living with IPF in the United States in the year 2000 and 34,000 new cases diagnosed per year. IPF is a disease of unknown etiology and myriad environmental factors are known to contribute to the development of the disease in susceptible individuals. During fibrosis, fibroblasts differentiate into myofibroblast cells that produce vast amounts of extracellular matrix (ECM) proteins that alter matrix rigidity and lung architecture impacting lung function. A critical constituent of the ECM is the core matrisome protein fibronectin (FN) that assembles into a FN matrix contributing to Collagen matrix formation and ECM rigidity. Von Hippel Lindau (VHL) protein is required for the FN matrix formation and is upregulated in the lungs of IPF patients. We have shown that the SOCS domain (Suppressors Of Cytokine Signaling), a 40 amino acid conserved domain in the SOCS family of proteins, targets VHL for degradation by a cullin-dependent ubiquitin ligase mechanism. We hypothesize that SOCS domain overexpression in myofibroblasts will result in degradation of the pathologic FN matrix in myofibroblasts and fibrosis reversal. We will perform these experiments using lung fibroblasts transduced with the SOCS domain and the SOCS domain mutant that is defective in VHL degradation. Using RNAseq and phosphoproteome analysis, we will develop a computational pipeline to identify probable signaling mediators in the process of myofibroblast reversal. Our in vitro findings, will be evaluated in a Bleomycin-induced in vivo mouse model of lung fibrosis to test the efficiency of fibrosis reversal by adenoviral-mediated delivery of the SOCS domain. We expect a reduction of fibrosis markers in our in vitro experiments and significant reversal of fibrosis in our in vivo model. The results from these experiments will offer new peptide based targets as well as provide therapeutic agents that can be used either on its own or in combination with existing therapies to reverse matrix formation and fibrosis.