1. The AP-1 Transcription Factor Fosl-2 Regulates Autophagy in Cardiac Fibroblasts during Myocardial Fibrogenesis
- Author
-
Gabriela Kania, Przemyslaw Blyszczuk, Amela Hukara, Oliver Distler, Burkhard Ludewig, Mara Stellato, Jemima Seidenberg, Karin Klingel, University of Zurich, and Kania, Gabriela
- Subjects
Male ,Cardiac fibrosis ,cardiac fibrosis ,1607 Spectroscopy ,Fos-Related Antigen-2 ,lcsh:Chemistry ,Mice ,0302 clinical medicine ,lcsh:QH301-705.5 ,Spectroscopy ,cardiac fibroblasts ,0303 health sciences ,Chemistry ,cardiac hypertrophy ,10051 Rheumatology Clinic and Institute of Physical Medicine ,General Medicine ,Middle Aged ,3. Good health ,Computer Science Applications ,AP-1 transcription factor ,030220 oncology & carcinogenesis ,Female ,1606 Physical and Theoretical Chemistry ,Myofibroblast ,autophagy ,Stromal cell ,1503 Catalysis ,ATG5 ,Mice, Transgenic ,610 Medicine & health ,Article ,Catalysis ,Inorganic Chemistry ,03 medical and health sciences ,medicine ,1312 Molecular Biology ,1706 Computer Science Applications ,Animals ,Humans ,Physical and Theoretical Chemistry ,Molecular Biology ,Fos-related antigen 2 ,030304 developmental biology ,Aged ,Heart Failure ,1604 Inorganic Chemistry ,Myocardium ,Organic Chemistry ,Autophagy ,Fibroblasts ,medicine.disease ,Angiotensin II ,Fibrosis ,Transcription Factor AP-1 ,lcsh:Biology (General) ,lcsh:QD1-999 ,Gene Expression Regulation ,Cancer research ,Transforming growth factor ,1605 Organic Chemistry - Abstract
Background: Pathological activation of cardiac fibroblasts is a key step in development and progression of cardiac fibrosis and heart failure. This process has been associated with enhanced autophagocytosis, but molecular mechanisms remain largely unknown. Methods and Results: Immunohistochemical analysis of endomyocardial biopsies showed increased activation of autophagy in fibrotic hearts of patients with inflammatory cardiomyopathy. In vitro experiments using mouse and human cardiac fibroblasts confirmed that blockade of autophagy with Bafilomycin A1 inhibited fibroblast-to-myofibroblast transition induced by transforming growth factor (TGF)-β. Next, we observed that cardiac fibroblasts obtained from mice overexpressing transcription factor Fos-related antigen 2 (Fosl-2tg) expressed elevated protein levels of autophagy markers: the lipid modified form of microtubule-associated protein 1A/1B-light chain 3B (LC3BII), Beclin-1 and autophagy related 5 (Atg5). In complementary experiments, silencing of Fosl-2 with antisense GapmeR oligonucleotides suppressed production of type I collagen, myofibroblast marker alpha smooth muscle actin and autophagy marker Beclin-1 in cardiac fibroblasts. On the other hand, silencing of either LC3B or Beclin-1 reduced Fosl-2 levels in TGF-β-activated, but not in unstimulated cells. Using a cardiac hypertrophy model induced by continuous infusion of angiotensin II with osmotic minipumps, we confirmed that mice lacking either Fosl-2 (Ccl19CreFosl2flox/flox) or Atg5 (Ccl19CreAtg5flox/flox) in stromal cells were protected from cardiac fibrosis. Conclusion: Our findings demonstrate that Fosl-2 regulates autophagocytosis and the TGF-β-Fosl-2-autophagy axis controls differentiation of cardiac fibroblasts. These data provide a new insight for the development of pharmaceutical targets in cardiac fibrosis.
- Published
- 2021
- Full Text
- View/download PDF