Targeting ADAMTS4 aggravates myocardial ischemia-reperfusion injury by impairing endothelial integrity and accelerating leukocyte infiltration

Background Myocardial ischemia-reperfusion injury (MIRI) is an inevitable consequence of reperfusion therapy and a major determinant of patient prognosis. ADAM Metallopeptidase with Thrombospondin Type 1 Motif 4 (ADAMTS4) is a metalloproteinase that has been implicated in endothelial damage and inflammatory cascades, yet its role in MIRI remains undefined. Methods MIRI was modeled in mice by left coronary artery ligation and subsequently subjected to mRNA sequencing. The role of ADAMTS4 was then dissected in vivo in these MIRI mice and in vitro in cardiac endothelial cells (ECs) exposed to oxygen-glucose deprivation/reoxygenation (OGD/R), using both primary murine cardiac ECs and human cardiac microvascular ECs (hCMECs). Results ADAMTS4 was markedly up-regulated in MIRI mouse myocardium and in both primary murine cardiac ECs and hCMECs subjected to OGD/R. ADAMTS4 inhibition preserved cardiac function, shrank infarct size, and attenuated cardiomyocyte damage. At the microvascular level, ADAMTS4 silencing restored CD31 and VE-Cadherin expression, curbed leukocyte adhesion molecules, and lowered tissue myeloperoxidase activity together with pro-inflammatory cytokines. Consequently, endothelial barrier dysfunction and leukocyte transmigration provoked by OGD/R were largely reversed. Mechanistic studies suggested that ADAMTS4 may be transcriptionally regulated by FosB and JunB. Upregulation of FosB or JunB significantly enhanced the transcriptional activity of ADAMTS4. Moreover, overexpression of ADAMTS4 abrogated the protection afforded by FosB/JunB knockdown, establishing ADAMTS4 as the critical downstream executor of activating protein-1 mediated injury in MIRI. Conclusion Overall, we established that FosB and JunB transcriptionally upregulate ADAMTS4, which in turn dismantles the cardiac endothelial barrier and fuels leukocyte infiltration to exacerbate MIRI.