Modulation of prosurvival signaling in fibroblasts by a protein kinase inhibitor protects against fibrotic tissue injury

Ragini Vittal, Jeffrey C. Horowitz, Bethany B. Moore, Hengmin Zhang, Fernando J. Martinez, Galen B. Toews, Theodore J. Standiford, Victor J. Thannickal

Research output: Contribution to journalArticlepeer-review

99 Scopus citations


Progressive fibrotic diseases involving diverse organ systems are associated with the persistence of fibroblasts/myofibroblasts in injured tissues. Activation of focal adhesion kinase (FAK) and protein kinase B (PKB/Akt) by transforming growth factor-β1 mediate stable induction of myofibroblast differentiation and survival. In this report, we demonstrate that transforming growth factor-β1-induced activation of both PKB/Akt and FAK are dose dependency inhibited by the protein kinase inhibitor, AG1879, in cultured human lung flbroblasts. In a murine model of intratracheal bleomycin-induced lung fibrosis, regions of active fibrogenesis demonstrate elevated expression of PKB/Akt and FAK phosphorylation in vivo, effects that are attenuated in mice receiving daily intraperitoneal infections of AG1879 (bleomycin-AG1879) versus a chemically inactive analog (bleomycin-control). PKB/Akt and FAK phosphorylation are elevated in fibroblasts isolated from lungs of bleomycin-injured mice, effects that are inhibited in bleomycin-AG1879 mice. Accumulation of α-smooth muscle actin-expressing myofibroblasts is markedly reduced in lungs of bleomycin-AG1879 mice. The numbers of recruited inflammatory cells were not significantly different between these groups. Bleomycin-AG1879 mice are protected from lung flbrosis as evidenced by histopathology, trichrome staining, and biochemical analysis for collagen. Thus, targeting of prosurvival signaling pathways in fibroblasts/myofibroblasts may provide a novel and effective strategy for anti-fibrotic therapy of treatment-unresponsive fibrotic disorders.

Original languageEnglish (US)
Pages (from-to)367-375
Number of pages9
JournalAmerican Journal of Pathology
Issue number2
StatePublished - Feb 2005

ASJC Scopus subject areas

  • Pathology and Forensic Medicine

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