Background and Purpose. The metalloprotease ADAM10 has been implicated in immune regulatory processes, is upregulated in response to specific heart pathologies e.g. ischemic heart failure and elevated serum levels of the ADAM10 substrates CX3CL1 and CXCL16 have been reported following infarction. The causal role of ADAM10 in cardiovascular diseases, however, is not known yet. By using human tissue biopsies, a cardiomyocyte-specific ADAM10 knockout mouse model (ADAM10 KO), and pharmacological ADAM10 inhibition we here comprehensively characterize the role of ADAM10 in the heart and in cardiac disease.

Methods and Results. We show that ADAM10 protein levels are upregulated in patients with ischemic cardiomyopathy (2-fold) and ADAM10 mRNA expression correlates with expression of atrial (ANP) and brain natriuretic peptide (BNP) mRNA. Upon infarction, ADAM10 expression is specifically induced in cardiomyocytes, and cardiomyocyte-specific ADAM10 KO as well as pharmacological inhibition (GI254023X) for only three days significantly improves overall survival, reduces scar size, and preserves cardiac function. FACS analysis and bulk RNA sequencing identify blunted ADAM10/CX3CL1-mediated neutrophil bone marrow egress and heart tissue infiltration as underlying mechanism. Diminished neutrophil migration resulted in long-term reduction of IL-1β-driven inflammation. Using cell culture experiments with ADAM10/CX3CL1 knockdown cardiomyocytes, we show that ADAM10-mediated ectodomain shedding of CX3CL1 specifically regulates neutrophil but not macrophage chemotaxis revealing a novel conceptual insight into how acute infarction triggers chemotactic signaling via ectodomain shedding.

Conclusion. Pharmacological and genetic targeting of the membrane sheddase ADAM10 is highly efficient for improving post-infarction cardiac function and survival via abolished post-translational CX3CL1 processing, neutrophil infiltration and IL-1β-dependent inflammation. Thus, our data reveal a novel therapeutic concept, which may close a clinically relevant therapeutic gap early after myocardial infarction.