Release of STK24/25 suppression on MEKK3 signaling in endothelial cells confers cerebral cavernous malformation

Knockdown of CCM3 promotes angiogenesis through activation and nuclear translocation of YAP/TAZ

Angiogenesis, a finely regulated process, plays a crucial role in the progression of various diseases. Cerebral cavernous malformation 3 (CCM3), alternatively referred to as programmed cell death 10 (PDCD10), stands as a pivotal functional gene with a broad distribution across the human body. However, the precise role of CCM3 in angiogenesis regulation has remained elusive. YAP/TAZ, as core components of the evolutionarily conserved Hippo pathway, have garnered increasing attention as a novel mechanism in angiogenesis regulation. Nonetheless, whether CCM3 regulates angiogenesis through YAP/TAZ mediation has not been comprehensively explored. In this study, our primary focus centers on investigating the regulation of angiogenesis through CCM3 knockdown mediated by YAP/TAZ. Silencing CCM3 significantly enhances the proliferation, migration, and tubular formation of human umbilical vein endothelial cells (HUVECs), thereby promoting angiogenesis. Furthermore, we observe an upregulation in the expression levels of VEGF and VEGFR2 within HUVECs upon silencing CCM3. Mechanistically, the evidence we provide suggests for the first time that endothelial cell CCM3 knockdown induces the activation and nuclear translocation of YAP/TAZ. Finally, we further demonstrate that the YAP/TAZ inhibitor verteporfin can reverse the pro-angiogenic effects of siCCM3, thereby confirming the role of CCM3 in angiogenesis regulation dependent on YAP/TAZ. In summary, our findings pave the way for potential therapeutic targeting of the CCM3-YAP/TAZ signaling axis as a novel approach to promote angiogenesis.

Plxnd1-mediated mechanosensing of blood flow controls the caliber of the Dorsal Aorta via the transcription factor Klf2

The cardiovascular system generates and responds to mechanical forces. The heartbeat pumps blood through a network of vascular tubes, which adjust their caliber in response to the hemodynamic environment. However, how endothelial cells in the developing vascular system integrate inputs from circulatory forces into signaling pathways to define vessel caliber is poorly understood. Using vertebrate embryos and in vitro-assembled microvascular networks of human endothelial cells as models, flow and genetic manipulations, and custom software, we reveal that Plexin-D1, an endothelial Semaphorin receptor critical for angiogenic guidance, employs its mechanosensing activity to serve as a crucial positive regulator of the Dorsal Aorta's (DA) caliber. We also uncover that the flow-responsive transcription factor KLF2 acts as a paramount mechanosensitive effector of Plexin-D1 that enlarges endothelial cells to widen the vessel. These findings illuminate the molecular and cellular mechanisms orchestrating the interplay between cardiovascular development and hemodynamic forces.