An endogenous MYDGF-ADAM17 axis mitigates cardiac fibrosis by attenuating transforming growth factor beta signaling

M. Korf-Klingebiel (Hannover)¹, X. Wu (Stanford)², J. A. Karck (Hannover)³, M. Reboll (Hannover)¹, Y. Wang (Hannover)¹, J. D. Schmitto (Hannover)⁴, D. Jonigk (Aachen)⁵, E. Giannitsis (Heidelberg)⁶, D. Duncker (Hannover)⁷, J. Bauersachs (Hannover)⁸, H. Milting (Bad Oeynhausen)⁹, Z. Yildirim (Stanford)², A. Pich (Hannover)¹⁰, F. Polten (Hannover)³, J. C. Wu (Stanford)¹¹, K. C. Wollert (Hannover)^1
1Medizinische Hochschule Hannover Molekulare und Translationale Kardiologie Hannover, Deutschland; ²Stanford University School of Medicine Stanford Cardiovascular Institute Stanford, USA; ³Medizinische Hochschule Hannover, Kardiologie und Angiologie Molekulare und Translationale Kardiologie Hannover, Deutschland; ⁴Medizinische Hochschule Hannover Klinik für Herz-, Thorax-, Transplantations- und Gefäßchirurgie, OE 6217 Hannover, Deutschland; ⁵Universitätklinikum Aachen Pathologisches Institut Aachen, Deutschland; ⁶Universitätsklinikum Heidelberg Klinik für Innere Med. III, Kardiologie, Angiologie u. Pneumologie Heidelberg, Deutschland; ⁷Medizinische Hochschule Hannover Klinik für Kardiologie und Angiologie Hannover, Deutschland; ⁸Medizinische Hochschule Hannover Kardiologie und Angiologie Hannover, Deutschland; ⁹Herz- und Diabeteszentrum NRW E.& H. Klessmann-Institut f. kardiovask. Forschung Bad Oeynhausen, Deutschland; ¹⁰Medizinische Hochschule Hannover Core Unit Proteomics Hannover, Deutschland; ¹¹Stanford University Medical Center Dept. of Pediatrics, Grant Buiding, Rm S-214 Stanford, USA

Myocardial fibrosis is a conserved pathological response to diverse insults and a critical determinant of heart failure progression. Therapies that halt or reverse cardiac fibrosis in patients are urgently needed. Here, we identify myeloid-derived growth factor (MYDGF) as an endogenous antifibrotic cytokine that restrains fibroblast activation through an ADAM17-dependent mechanism regulating transforming growth factor beta receptor (TGFBR) turnover. In a mouse model of angiotensin II-induced heart fibrosis and failure, MYDGF protein abundance markedly increased in the left ventricle (4.9-fold, maximum on day 7) and the circulation (4.1-fold), mirroring elevations observed in left ventricular tissue and plasma samples from patients with end-stage heart failure. Single-cell RNA-seq identified fibroblasts, endothelial cells, and monocytes/macrophages as the main Mydgf mRNA-expressing cell types in both murine and human failing hearts. Genetic loss (global knockout) of Mydgf exacerbated interstitial fibrosis (Sirius-red staining) and systolic and diastolic dysfunction (2D and tissue-Doppler echocardiography) in angiotensin II-treated mice. Conversely, subcutaneous administration of recombinant MYDGF using osmotic minipumps (10 g/d for 14 d) reduced collagen accumulation and preserved left ventricular function in this model. In vitro, MYDGF (100 ng/mL) suppressed transforming growth factor beta (TGFB) 1-induced SMAD activation, proliferation, migration, and alpha smooth muscle actin (SMA) and collagen expression in mouse embryonic fibroblasts (MEFs). Mechanistically, MYDGF promoted cleavage and shedding of the TGFBR1 ectodomain, as revealed by immunoblotting and mass spectrometry. We performed a loss-of-function screen targeting the top 10 fibroblast-expressed metalloproteases and identified ADAM17 as the responsible TGFBR1 sheddase. Consistently, MYDGF activated ADAM17 in MEFs, as evidenced by enhanced phosphorylation of threonine 735 (immunoblotting) and enzymatic activity (FRET peptide-based assay). Pharmacological inhibition (TAPI-1) or shRNA-mediated RNA knockdown of ADAM17 abolished MYDGF’s antifibrotic effects, defining ADAM17-induced TGFBR1 shedding as a central mechanism mediating MYDGF’s antifibrotic effects. To start exploring translational implications, we studied primary cardiac fibroblasts from patients with heart failure, with or without TGFB1 stimulation. MYDGF enhanced ADAM17 phosphorylation, and reverted the cells toward a quiescent phenotype. Extending these findings to a multicellular environment, we employed human iPSC-derived 3D-cardiac organoids containing cardiomyocytes, endothelial cells, and alpha SMA-reporter fibroblasts. As shown by time-lapse fluorescence imaging, MYDGF markedly reduced alpha SMA expression in TGFB1, angiotensin II, and phenylephrine-stimulated organoids (0.55 ± 0.11-fold), thus validating MYDGF’s antifibrotic activity in a human multicellular context. Together, these findings reveal a previously unrecognized MYDGF-ADAM17 pathway promoting TGFBR1 ectodomain shedding. Beyond elucidating a key antifibrotic pathway, this work positions MYDGF as a therapeutic candidate to mitigate progressive cardiac fibrosis in heart failure