TGFβ promotes fibrosis by MYST1-dependent epigenetic regulation of autophagy

Activation of fibroblasts is essential for physiological tissue repair. Uncontrolled activation of fibroblasts, however, may lead to tissue fibrosis with organ dysfunction. Although several pathways capable of promoting fibroblast activation and tissue repair have been identified, their interplay in the context of chronic fibrotic diseases remains incompletely understood. Here, we provide evidence that transforming growth factor-beta (TGF beta) activates autophagy by an epigenetic mechanism to amplify its profibrotic effects. TGF beta induces autophagy in fibrotic diseases by SMAD3-dependent downregulation of the H4K16 histone acetyltransferase MYST1, which regulates the expression of core components of the autophagy machinery such as ATG7 and BECLIN1. Activation of autophagy in fibroblasts promotes collagen release and is both, sufficient and required, to induce tissue fibrosis. Forced expression of MYST1 abrogates the stimulatory effects of TGF beta on autophagy and re-establishes the epigenetic control of autophagy in fibrotic conditions. Interference with the aberrant activation of autophagy inhibits TGF beta -induced fibroblast activation and ameliorates experimental dermal and pulmonary fibrosis. These findings link uncontrolled TGF beta signaling to aberrant autophagy and deregulated epigenetics in fibrotic diseases and may contribute to the development of therapeutic interventions in fibrotic diseases. Uncontrolled activation of fibroblasts contributes to tissue fibrosis and organ dysfunction. Here the authors demonstrate that the epigenetic control of autophagy is disturbed by a TGF beta -dependent downregulation of MYST1 in systemic sclerosis patients. Restoration of the epigenetic control of autophagy reduces fibroblast activation and ameliorates fibrotic tissue remodeling.

Automated summary

This study demonstrates that TGF beta activates autophagy through an epigenetic mechanism, promoting fibrotic diseases. Inhibition of aberrant autophagy activation can suppress TGF beta-induced fibroblast activation and ameliorate experimental dermal and pulmonary fibrosis.