TGF-β–induced epigenetic deregulation of SOCS3 facilitates STAT3 signaling to promote fibrosis
Clara Dees, … , Georg Schett, Jörg H.W. Distler
Clara Dees, … , Georg Schett, Jörg H.W. Distler
Published January 28, 2020
Citation Information: J Clin Invest. 2020;130(5):2347-2363. https://doi.org/10.1172/JCI122462.
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Research Article Cell biology Immunology

TGF-β–induced epigenetic deregulation of SOCS3 facilitates STAT3 signaling to promote fibrosis

Abstract

Fibroblasts are key effector cells in tissue remodeling. They remain persistently activated in fibrotic diseases, resulting in progressive deposition of extracellular matrix. Although fibroblast activation may be initiated by external factors, prolonged activation can induce an “autonomous,” self-maintaining profibrotic phenotype in fibroblasts. Accumulating evidence suggests that epigenetic alterations play a central role in establishing this persistently activated pathologic phenotype of fibroblasts. We demonstrated that in fibrotic skin of patients with systemic sclerosis (SSc), a prototypical idiopathic fibrotic disease, TGF-β induced the expression of DNA methyltransferase 3A (DNMT3A) and DNMT1 in fibroblasts in a SMAD-dependent manner to silence the expression of suppressor of cytokine signaling 3 (SOCS3) by promoter hypermethylation. Downregulation of SOCS3 facilitated activation of STAT3 to promote fibroblast-to-myofibroblast transition, collagen release, and fibrosis in vitro and in vivo. Reestablishment of the epigenetic control of STAT3 signaling by genetic or pharmacological inactivation of DNMT3A reversed the activated phenotype of SSc fibroblasts in tissue culture, inhibited TGF-β–dependent fibroblast activation, and ameliorated experimental fibrosis in murine models. These findings identify a pathway of epigenetic imprinting of fibroblasts in fibrotic disease with translational implications for the development of targeted therapies in fibrotic diseases.

Authors

Clara Dees, Sebastian Pötter, Yun Zhang, Christina Bergmann, Xiang Zhou, Markus Luber, Thomas Wohlfahrt, Emmanuel Karouzakis, Andreas Ramming, Kolja Gelse, Akihiko Yoshimura, Rudolf Jaenisch, Oliver Distler, Georg Schett, Jörg H.W. Distler

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Figure 8

Mutation of the SOCS3-binding motif of JAK2 abrogates the beneficial effects of 5-aza on TGF-β–induced collagen synthesis and myofibroblast differentiation.

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Mutation of the SOCS3-binding motif of JAK2 abrogates the beneficial eff...
(A) Representative Western blot and quantitation of co-IP of JAK2, STAT3, and SOCS3 in normal dermal fibroblasts stimulated with TGF-β and incubated with 5-aza. n = 4 fibroblast lines from different donors with 3 technical replicates each. (B) Effects of 5-aza and of siRNA-mediated knockdown of SOCS3 (left) or DNMT3A (right) on TGF-β–induced firefly luciferase activity under the control of a STAT3-responsive promoter. n = 6 fibroblast lines from different donors with 3 technical replicates each. (C) Representative Western blot and quantitation of the pSTAT3/STAT3 ratio upon overexpression of WT JAK2 (JAK2-WT) or mutated JAK2 with a defective SOCS3-binding site (JAK2-G1071V;M1073A) in normal dermal fibroblasts stimulated with TGF-β and incubated with 5-aza. n = 4 fibroblast lines from different donors with 3 technical replicates each. (D) COL1A1 mRNA and collagen protein levels in cell culture media upon overexpression of WT JAK2 or mutated JAK2 (n = 5 fibroblast lines from different donors with 2 technical replicates each). (E) Representative stainings and quantitations of α-SMA (green) and stress fibers (red) upon overexpression of WT or mutated JAK2 in normal fibroblasts. n = 3 fibroblast lines from different donors with 2 technical replicates each. Original magnification, ×400. Scale bars: 100 μm. Data are depicted as the median with interquartile range. Each dot represents an individual result. One-way ANOVA with Tukey’s range test as post hoc analysis was used for statistical analyses. 0.05 > *P ≥ 0.01; 0.01 > **P ≥ 0.001; ***P < 0.001.