Open AccessRNAi screening identifies a mechanosensitive ROCK-JAK2-STAT3 network central to myofibroblast activation
Author(s) -
Raymond Oh,
Andrew J. Haak,
Karry M. J. Smith,
Giovanni Ligresti,
Kyoung Moo Choi,
Tiao Xie,
Shaohua Wang,
P. Walters,
Michael A. Thompson,
Michele Freeman,
L. Manlove,
Vivian Chu,
Carol FeghaliBostwick,
Anja C. Roden,
Jürgen Schymeinsky,
Christina M. Pabelick,
Y. S. Prakash,
Robert Vassallo,
Daniel J. Tschumperlin
Publication year - 2018
Publication title -
journal of cell science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.384
H-Index - 278
eISSN - 1477-9137
pISSN - 0021-9533
DOI - 10.1242/jcs.209932
Subject(s) - myofibroblast , fibrosis , biology , pulmonary fibrosis , microbiology and biotechnology , cardiac fibrosis , stat3 , wound healing , cancer research , phenotype , signal transduction , pathology , immunology , gene , medicine , genetics
Myofibroblasts play key roles in wound healing and pathologic fibrosis. Here we undertook an RNAi screen to characterize myofibroblast regulatory genes, using a high-content imaging approach to quantify alpha-smooth muscle actin stress fibers in cultured human fibroblasts. Screen hits were validated on physiological compliance hydrogels, and selected hits tested in primary fibroblasts from patients with idiopathic pulmonary fibrosis. Our RNAi screen led to the identification of STAT3 as an essential mediator of myofibroblast activation and function. Strikingly, we found that STAT3 phosphorylation, while responsive to exogenous ligands on both soft and stiff matrices, is innately active on a stiff matrix in a ligand/receptor independent, but ROCK and JAK2 dependent fashion. These results demonstrate how a cytokine-inducible signal can become persistently activated by pathological matrix stiffening. Consistent with a pivotal role for this pathway in driving persistent fibrosis, a STAT3 inhibitor attenuated murine pulmonary fibrosis when administered in a therapeutic fashion after bleomycin injury. Our results identify novel genes essential for the myofibroblast phenotype, and point to STAT3 as an important target in pulmonary fibrosis and other fibrotic diseases.