Reduced SPAG17 Expression in Systemic Sclerosis Triggers Myofibroblast Transition and Drives Fibrosis

Paulene Sapao, Elisha D.O. Roberson, Bo Shi, Shervin Assassi, Brian Skaug, Fred Lee, Alexandra Naba, Bethany E. Perez White, Carlos Córdova-Fletes, Pei Suen Tsou, Amr H. Sawalha, Johann E. Gudjonsson, Feiyang Ma, Priyanka Verma, Dibyendu Bhattacharyya, Mary Carns, Jerome F. Strauss, Delphine Sicard, Daniel J. Tschumperlin, Melissa I. ChamperPaul J. Campagnola, Maria E. Teves*, John Varga

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


Systemic sclerosis (SSc) is a clinically heterogeneous fibrotic disease with no effective treatment. Myofibroblasts are responsible for unresolving synchronous skin and internal organ fibrosis in SSc, but the drivers of sustained myofibroblast activation remain poorly understood. Using unbiased transcriptome analysis of skin biopsies, we identified the downregulation of SPAG17 in multiple independent cohorts of patients with SSc, and by orthogonal approaches, we observed a significant negative correlation between SPAG17 and fibrotic gene expression. Fibroblasts and endothelial cells explanted from SSc skin biopsies showed reduced chromatin accessibility at the SPAG17 locus. Remarkably, mice lacking Spag17 showed spontaneous skin fibrosis with increased dermal thickness, collagen deposition and stiffness, and altered collagen fiber alignment. Knockdown of SPAG17 in human and mouse fibroblasts and microvascular endothelial cells was accompanied by spontaneous myofibroblast transformation and markedly heightened sensitivity to profibrotic stimuli. These responses were accompanied by constitutive TGF-β pathway activation. Thus, we discovered impaired expression of SPAG17 in SSc and identified, to our knowledge, a previously unreported cell-intrinsic role for SPAG17 in the negative regulation of fibrotic responses. These findings shed fresh light on the pathogenesis of SSc and may inform the search for innovative therapies for SSc and other fibrotic conditions through SPAG17 signaling.

Original languageEnglish (US)
Pages (from-to)284-293
Number of pages10
JournalJournal of Investigative Dermatology
Issue number2
StatePublished - Feb 2023

ASJC Scopus subject areas

  • Dermatology
  • Molecular Biology
  • Biochemistry
  • Cell Biology


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