Project #3: Ubiquitin E3 ligases in SSc Systemic sclerosis (SSc) is a progressive multi-organ system fibrotic disorder associated with autoimmunity. The leading causes of SSc-related death are pulmonary hypertension (PAH) and interstitial lung disease (ILD). PAH affects 10-15% of SSc patients. The prevalence of ILD varies from 40 to 65% in cohort studies. SSc-ILD is the subject of CORT Project #3. Common to many of the SSc disease phenotypes, include the skin and the lung, is the observation that fibroblasts, the principal effector cells of fibrosis, assume the contractile myofibroblast phenotype, synthesize matrix, and exhibit a pathologically increased lifespan. A traditional approach to discover novel genes involved in the pathogenesis of pulmonary fibrosis has been to perform genome-wide screening to uncover dysregulated RNA species that may be involved in the pathogenesis of disease. However, this approach may miss the critical role of proteins that are NOT regulated at the level of transcription but rather through protein degradation, particularly through the ubiquitin-proteasome system (UPS) mediated by ubiquitin E3 enzymes. Our recent studies using a large number of idiopathic pulmonary fibrosis (IPF) and SSc lung samples have uncovered an array of several, previously unsuspected, molecular targets. In particular, we have identified two highly novel pro- fibrotic signaling pathways in SSc fibroblasts: First is the loss of a new collagen 1 gene repressor, E2 transcriptional factor 8 (E2F8) by a ubiquitin E3 ligase, Fbxo16. This ultimately leads to increased collagen synthesis in SSc fibroblasts. The second is a new protein isoform, termed FIEL1 (Fibrosis- Inducing E3 Ligase 1), which potently stimulates the central pro-fibrotic cytokine, TGF?, signaling pathway through the site-specific ubiquitination and degradation of the TGF? inhibitor PIAS4. Further, we have developed a first-in-class small molecule inhibitor towards FIEL1 that is highly effective in ameliorating fibrosis in mice. Thus, we hypothesize that dysregulation of members of E3 ubiquitin ligase system drives the fibrotic phenotype in SSc. In this project, we propose to screen SSc-ILD lungs and lung fibroblasts derived from SSc-ILD lungs for dysregulated expression of members of the SCF- and HECT-domain ubiquitin E3 ligases and to assay their function in mediating the pathologic myofibroblast phenotype. We will then design small molecule inhibitors for these E3 ligases and test them for effectiveness in animal models of lung fibrosis as well as our unique ex vivo diseased human lung perfusion and culture systems here at the University of Pittsburgh. These proposed studies will help us discover a new set of potentially druggable targets underlying the pathobiology of fibrotic pathways in SSc. These studies will provide a fundamental platform for a unique and potentially transformative initiative in SSc-ILD. Our project will interact very closely with the other CORT projects and cores to discover the overlapping biology of dysregulated ubiquitin E3 ligases in SSc-PAH and SSc-skin disease.

National Institute of Health (NIH)
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Specialized Center (P50)
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Special Emphasis Panel (ZAR1)
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University of Pittsburgh
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Stifano, Giuseppina; Sornasse, Thierry; Rice, Lisa M et al. (2018) Skin Gene Expression Is Prognostic for the Trajectory of Skin Disease in Patients With Diffuse Cutaneous Systemic Sclerosis. Arthritis Rheumatol 70:912-919
Franks, Jennifer M; Cai, Guoshuai; Whitfield, Michael L (2018) Feature specific quantile normalization enables cross-platform classification of molecular subtypes using gene expression data. Bioinformatics 34:1868-1874
Apostolidis, Sokratis A; Stifano, Giuseppina; Tabib, Tracy et al. (2018) Single Cell RNA Sequencing Identifies HSPG2 and APLNR as Markers of Endothelial Cell Injury in Systemic Sclerosis Skin. Front Immunol 9:2191
Fleury, Michelle; Belkina, Anna C; Proctor, Elizabeth A et al. (2018) Increased Expression and Modulated Regulatory Activity of Coinhibitory Receptors PD-1, TIGIT, and TIM-3 in Lymphocytes From Patients With Systemic Sclerosis. Arthritis Rheumatol 70:566-577
Moll, Matthew; Christmann, Romy B; Zhang, Yuqing et al. (2018) Patients with systemic sclerosis-associated pulmonary arterial hypertension express a genomic signature distinct from patients with interstitial lung disease. J Scleroderma Relat Disord 3:242-248
Meiners, Silke; Evankovich, John; Mallampalli, Rama K (2018) The ubiquitin proteasome system as a potential therapeutic target for systemic sclerosis. Transl Res 198:17-28
Rice, Lisa M; Mantero, Julio C; Stratton, Eric A et al. (2018) Serum biomarker for diagnostic evaluation of pulmonary arterial hypertension in systemic sclerosis. Arthritis Res Ther 20:185
Goswami, Rishov; Cohen, Jonathan; Sharma, Shweta et al. (2017) TRPV4 ION Channel Is Associated with Scleroderma. J Invest Dermatol 137:962-965
Cheong, Fei-Ying; Gower, Adam C; Farber, Harrison W (2017) Changes in gene expression profiles in patients with pulmonary arterial hypertension associated with scleroderma treated with tadalafil. Semin Arthritis Rheum 46:465-472
Yamashita, Takashi; Asano, Yoshihide; Taniguchi, Takashi et al. (2017) Glycyrrhizin Ameliorates Fibrosis, Vasculopathy, and Inflammation in Animal Models of Systemic Sclerosis. J Invest Dermatol 137:631-640

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