Changes in nascent chromatin structure regulate activation of the pro-fibrotic transcriptome and myofibroblast emergence in organ fibrosis

Morgan D Basta; Svetlana Petruk; Ross Summer; Joel Rosenbloom; Peter J Wermuth; Edward Macarak; Alex V Levin; Alexander Mazo; Janice L Walker

doi:10.1016/j.isci.2023.106570

Changes in nascent chromatin structure regulate activation of the pro-fibrotic transcriptome and myofibroblast emergence in organ fibrosis

iScience. 2023 Apr 6;26(5):106570. doi: 10.1016/j.isci.2023.106570. eCollection 2023 May 19.

Authors

Morgan D Basta¹, Svetlana Petruk², Ross Summer³, Joel Rosenbloom⁴, Peter J Wermuth⁴, Edward Macarak⁴, Alex V Levin⁵, Alexander Mazo², Janice L Walker^{1

6}

Affiliations

¹ Department of Pathology and Genomic Medicine, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA.
² Department of Biochemistry and Molecular Biology, Sidney Kimmel Medical College, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA.
³ Center for Translational Medicine, The Jane and Leonard Korman Respiratory Institute at the Sidney Kimmel Medial College, Thomas Jefferson University, Philadelphia, PA 19107, USA.
⁴ Department of Dermatology and Cutaneous Biology, The Joan and Joel Rosenbloom Research Center for Fibrotic Diseases, Sidney Kimmel Medical College Thomas Jefferson University, Philadelphia, PA 19107, USA.
⁵ Wills Eye Hospital, Philadelphia, PA 19107, USA.
⁶ Department of Ophthalmology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA.

Abstract

Cell reprogramming to a myofibroblast responsible for the pathological accumulation of extracellular matrix is fundamental to the onset of fibrosis. Here, we explored how condensed chromatin structure marked by H3K72me3 becomes modified to allow for activation of repressed genes to drive emergence of myofibroblasts. In the early stages of myofibroblast precursor cell differentiation, we discovered that H3K27me3 demethylase enzymes UTX/KDM6B creates a delay in the accumulation of H3K27me3 on nascent DNA revealing a period of decondensed chromatin structure. This period of decondensed nascent chromatin structure allows for binding of pro-fibrotic transcription factor, Myocardin-related transcription factor A (MRTF-A) to nascent DNA. Inhibition of UTX/KDM6B enzymatic activity condenses chromatin structure, prevents MRTF-A binding, blocks activation of the pro-fibrotic transcriptome, and results in an inhibition of fibrosis in lens and lung fibrosis models. Our work reveals UTX/KDM6B as central coordinators of fibrosis, highlighting the potential to target its demethylase activity to prevent organ fibrosis.

Keywords: Epigenetics; Molecular mechanism of gene regulation; Molecular physiology; Transcriptomics.

Abstract

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