Transforming growth factor-β-dependent Wnt secretion controls myofibroblast formation and myocardial fibrosis progression in experimental autoimmune myocarditis.
OBJECTIVE
Myocardial fibrosis critically contributes to cardiac dysfunction in inflammatory dilated cardiomyopathy (iDCM). Activation of transforming growth factor-β (TGF-β) signalling is a key-step in promoting tissue remodelling and fibrosis in iDCM. Downstream mechanisms controlling these processes, remain elusive.


RESULTS
Experimental autoimmune myocarditis (EAM) was induced in BALB/c mice with heart-specific antigen and adjuvant. Using heart-inflammatory precursors, as well as mouse and human cardiac fibroblasts, we demonstrated rapid secretion of Wnt proteins and activation of Wnt/β-catenin pathway in response to TGF-β signalling. Inactivation of extracellular Wnt with secreted Frizzled-related protein 2 (sFRP2) or inhibition of Wnt secretion with Wnt-C59 prevented TGF-β-mediated transformation of inflammatory precursors and cardiac fibroblasts into pathogenic myofibroblasts. Inhibition of T-cell factor (TCF)/β-catenin-mediated transcription with ICG-001 or genetic loss of β-catenin also prevented TGF-β-induced myofibroblasts formation. Furthermore, blocking of Smad-independent TGF-β-activated kinase 1 (TAK1) pathway completely abrogated TGF-β-induced Wnt secretion. Activation of Wnt pathway in the absence of TGF-β, however, failed to transform precursors into myofibroblasts. The critical role of Wnt axis for cardiac fibrosis in iDCM is also supported by elevated Wnt-1/Wnt-5a levels in human samples from hearts with myocarditis. Accordingly, and as an in vivo proof of principle, inhibition of Wnt secretion or TCF/β-catenin-mediated transcription abrogated the development of post-inflammatory fibrosis in EAM.


CONCLUSIONS
We identified TAK1-mediated rapid Wnt protein secretion as a novel downstream key mechanism of TGF-β-mediated myofibroblast differentiation and myocardial fibrosis progression in human and mouse myocarditis. Thus, pharmacological targeting of Wnts might represent a promising therapeutic approach against iDCM in the future.
Cardioimmunology, Center for Molecular Cardiology, University of Zurich, Wagistr. 12, CH-8952 Schlieren, Switzerland.|Department of Clinical Immunology, Jagiellonian University Medical College, Wielicka 265, 30-663 Cracow, Poland.|Department of Medicine, GZO-Zurich Regional Health Center, Spitalstr. 66, CH-8620 Wetzikon, Switzerland.
Przemyslaw
P
Blyszczuk
Cardioimmunology, Center for Molecular Cardiology, University of Zurich, Wagistr. 12, CH-8952 Schlieren, Switzerland.|Department of Medicine, GZO-Zurich Regional Health Center, Spitalstr. 66, CH-8620 Wetzikon, Switzerland.
Björn
B
Müller-Edenborn
Institute of Molecular Life Sciences, University of Zurich, Winterthurerstr. 190, CH-8057 Zurich, Switzerland.
Tomas
T
Valenta
Center for Molecular Cardiology, University of Zurich, Wagistr. 12, CH-8952 Schlieren, Switzerland.|ETH Zurich, Institute of Food, Nutrition and Health, Laboratory of Translational Nutrition Biology, Schorenstrasse 16, CH-8603 Schwerzenbach, Switzerland.
Elena
E
Osto
Research of Systemic Autoimmune Diseases, Division of Rheumatology, University Hospital Zurich, Wagistr. 14, CH-8952 Schlieren, Switzerland.
Mara
M
Stellato
Sophistolab AG, Hofackerstrasse 40A, 4132 Muttenz, Switzerland.
Silvia
S
Behnke
Institute of Pathology, University Hospital, Hebelstr. 20, CH-4031 Basle, Switzerland.
Katharina
K
Glatz
Institute of Molecular Life Sciences, University of Zurich, Winterthurerstr. 190, CH-8057 Zurich, Switzerland.
Konrad
K
Basler
Center for Molecular Cardiology, University of Zurich, Wagistr. 12, CH-8952 Schlieren, Switzerland.|Department of Cardiology, University Heart Center, University Hospital Zurich, Raemistr. 100, CH-8001 Zurich, Switzerland.
Thomas F
TF
Lüscher
Research of Systemic Autoimmune Diseases, Division of Rheumatology, University Hospital Zurich, Wagistr. 14, CH-8952 Schlieren, Switzerland.
Oliver
O
Distler
Cardioimmunology, Center for Molecular Cardiology, University of Zurich, Wagistr. 12, CH-8952 Schlieren, Switzerland.|Department of Medicine, GZO-Zurich Regional Health Center, Spitalstr. 66, CH-8620 Wetzikon, Switzerland.
Urs
U
Eriksson
Research of Systemic Autoimmune Diseases, Division of Rheumatology, University Hospital Zurich, Wagistr. 14, CH-8952 Schlieren, Switzerland.
Gabriela
G
Kania
D000818:Animals; D001327:Autoimmune Diseases / Q000209:etiology*; D044482:Benzeneacetamides / Q000494:pharmacology; D002454:Cell Differentiation / Q000502:physiology; D018450:Disease Progression; D005355:Fibrosis / Q000503:physiopathology; D006801:Humans; D020930:MAP Kinase Kinase Kinases / Q000378:metabolism / Q000502:physiology; D008565:Membrane Proteins / Q000378:metabolism; D008807:Mice, Inbred BALB C; D009205:Myocarditis / Q000209:etiology*; D009206:Myocardium / Q000473:pathology*; D058628:Myofibroblasts / Q000502:physiology; D011725:Pyridines / Q000494:pharmacology; D015398:Signal Transduction / Q000502:physiology; D013234:Stem Cells / Q000502:physiology; D051820:TCF Transcription Factors / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000502:physiology*; D018754:Ventricular Dysfunction / Q000503:physiopathology; D051153:Wnt Proteins / Q000378:metabolism*; D000071818:Wnt-5a Protein / Q000378:metabolism; D051155:Wnt1 Protein / Q000378:metabolism; D051176:beta Catenin / Q000378:metabolism; D000099151:MAP Kinase Kinase Kinase 7; D000094742:Secreted Frizzled-Related Proteins
D044482:Benzeneacetamides; D020930:MAP Kinase Kinase Kinases; D008565:Membrane Proteins; D011725:Pyridines; D051820:TCF Transcription Factors; D016212:Transforming Growth Factor beta; D051153:Wnt Proteins; D000071818:Wnt-5a Protein; D051155:Wnt1 Protein; D051176:beta Catenin; D000099151:MAP Kinase Kinase Kinase 7; C579131:2-(4-(2-methylpyridin-4-yl)phenyl)-N-(4-(pyridin-3-yl)phenyl)acetamide; C491628:Sfrp2 protein, mouse; D000094742:Secreted Frizzled-Related Proteins; C085389:WNT5A protein, human
CD133 inflammatory progenitor; Cardiac fibroblasts; Experimental autoimmune myocarditis; Myofibroblast; TGF-β signalling; Wnt-TAK1 signalling