Androgen Receptor Governs Tip Cell Formation in Cerebrovascular Malformations.

Abstract

Cerebrovascular malformations are a pivotal cause of hemorrhage and neurological disability, orchestrated largely by aberrant vascular homeostasis. However, a malformed angiogenic regulation pattern remains elusive. Single-cell transcriptome analysis uncovered the endothelial features of human cerebral cavernous malformations and brain arteriovenous malformations, 2 typical cerebrovascular malformation diseases. Endothelial AR (androgen receptor, a steroid receptor in the nuclear receptor superfamily) overexpression was conducted to investigate its involvement in tip cell formation. ARD-2585, an AR degrader, was applied to mouse models of cerebral cavernous malformations (endothelial-specific <i>Pdcd10</i> knockout mice) and brain arteriovenous malformations (endothelial-specific <i>Kras</i>^<i>G12D</i> mutant [<i>Kras</i>^<i>G12D</i>] mice) to evaluate its vascular rescue potential. We profiled single-cell transcriptomes of 13 human cerebrovascular malformation samples (10 cerebral cavernous malformations and 3 brain arteriovenous malformations) and 13 control brain samples, identifying a crucial pathological tip cell population in lesions. Integrative bioinformatics revealed a systemic endothelial regulatory network, with AR as a key regulator of this aberrant state. AR expression was elevated in endothelial cells from both human cerebrovascular malformations and <i>Pdcd10</i> knockout/<i>Kras</i>^<i>G12D</i> mice, correlating with suppressed Dll4 (delta-like canonical Notch ligand 4)-Notch signaling. AR overexpression augmented endothelial tube formation, filopodia extension, and polarization in vitro and fostered sex-independent vascular sprouting in vivo. High levels of AR facilitated proangiogenic gene transcription by recruiting coactivators EP300 (EP300 lysine acetyltransferase)/CBP (CREB binding lysine acetyltransferase), augmenting histone H3 lysine 18/histone H3 lysine 27 acetylation, and boosting chromatin accessibility, potentially independent of androgen. Notably, ARD-2585 treatment effectively normalized vascular anomalies and alleviated cerebral hemorrhage in <i>Pdcd10</i> knockout and <i>Kras</i>^<i>G12D</i> mice. We delineated a novel androgen-independent AR-mediated endothelial sprouting pattern in malformed cerebrovasculature, highlighting a promising foundation for developing interventions targeting tip cells in angiogenic diseases.