A TGFβ-Responsive Gene Signature Is Associated with a Subset of Diffuse Scleroderma with Increased Disease Severity

Systemic sclerosis is a complex disease with widespread skin fibrosis and variable visceral organ involvement. Since transforming growth factor-β (TGFβ) has been implicated in driving fibrosis in systemic sclerosis, a mechanism-derived gene expression signature was used to assay TGFβ-responsive gene expression in the skin of patients with systemic sclerosis (SSc). Primary dermal fibroblasts from patients with diffuse SSc (dSSc) and healthy controls were treated with TGFβ, and the genome-wide gene expression was measured on DNA microarrays over a time course of 24hours. Eight hundred and ninety-four probes representing 674 uniquely annotated genes were identified as TGFβ responsive. Expression of the TGFβ-responsive signature was examined in skin biopsies from 17 dSSc, seven limited SSc (lSSc), three morphea patients, and six healthy controls. The TGFβ-responsive signature was expressed in 10 out of 17 dSSc skin biopsies, but was not found in lSSc, morphea, or healthy control biopsies. Expression of dSSC the TGFβ-responsive signature stratifies patients into two major groups, one of which corresponds to the “diffuse-proliferation” intrinsic subset that showed higher modified Rodnan skin score and a higher likelihood of scleroderma lung disease. The TGFβ-responsive signature is found in only a subset of dSSc patients who could be targeted by specific therapies