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Biology subjects

Daneva, Z.

Publications and source records attributed to Daneva, Z..

3 recordsLinked to original sources

AKAP5 and Caveolin-1 organize opposing nanodomains that regulate smooth muscle contraction and blood pressure

TRPV4 ion channels in vascular smooth muscle cells (SMCs) are crucial regulators of blood pressure, and their functional effects are differentially shaped by their signaling partners. However, the mechanisms by which TRPV4 channels are compartmentalized into distinct signaling nanodomains with opposite impacts on blood pressure remain unclear. Here, we identify the scaffolding proteins that compartmentalize TRPV4 channels into discrete nanometer-scale signaling domains at the SMC plasma membrane and define how these nanodomains produce opposing effects on vasoconstriction and blood pressure. We show that AKAP5 anchors a nanodomain linking 1-adrenergic receptors, protein kinase C and TRPV4 channels, thereby driving sympathetic vasoconstriction and blood pressure elevation. In contrast, caveolin-1 promotes a mechanosensitive nanodomain comprising Piezo1, TRPV4, and BK channels that mediates vasodilation and a decrease in blood pressure. In hypertension, AKAP5-dependent constrictor nanodomains are hyperactive, whereas caveolin-1-based dilator nanodomains are hypoactive, shifting the balance toward pathological vasoconstriction. These findings reveal fundamental mechanisms that organize smooth muscle TRPV4 channels into spatially and functionally distinct nanodomains regulating blood pressure and show how disruption of this organization contributes to blood pressure elevation in hypertension.

physiology↗

Purinergic P2Y2 Receptor-Induced Activation of Endothelial TRPV4 Channels Mediates Lung Ischemia-Reperfusion Injury

Lung ischemia-reperfusion injury (IRI), characterized by inflammation, vascular permeability, and lung edema, is the major cause of primary graft dysfunction after lung transplantation. We recently reported that endothelial cell (EC) TRPV4 channels play a central role in lung edema and dysfunction after IR. However, the cellular mechanisms for lung IR-induced activation of endothelial TRPV4 channels are unknown. In a left-lung hilar ligation model of IRI in mice, we found that lung IR increases the efflux of extracellular ATP (eATP) through pannexin 1 (Panx1) channels at the EC membrane. Elevated eATP activated elementary Ca2+ influx signals through endothelial TRPV4 channels through purinergic P2Y2 receptor (P2Y2R) signaling. P2Y2R-dependent activation of TRPV4 channels was also observed in human and mouse pulmonary microvascular endothelium in ex vivo and in vitro surrogate models of lung IR. Endothelium-specific deletion of P2Y2R, TRPV4, and Panx1 in mice had substantial protective effects against lung IR-induced activation of endothelial TRPV4 channels, lung edema, inflammation, and dysfunction. These results identify endothelial P2Y2R as a novel mediator of lung edema, inflammation, and dysfunction after IR, and show that disruption of endothelial Panx1-P2Y2R-TRPV4 signaling pathway could represent a promising therapeutic strategy for preventing lung IRI after transplantation.

physiology↗

Endothelial Pannexin 1-TRPV4 channel signaling lowers pulmonary arterial pressure

Pannexin 1 (Panx1) is an ATP-efflux channel that controls endothelial function in the systemic circulation. However, the roles of endothelial Panx1 in resistance-sized pulmonary arteries (PAs) are unknown. Extracellular ATP dilates PAs through activation of endothelial TRPV4 (transient receptor potential vanilloid 4) ion channels. We hypothesized that endothelial Panx1-ATP- TRPV4 channel signaling promotes vasodilation and lowers pulmonary arterial pressure (PAP). Endothelial, but not smooth muscle, knockout of Panx1 or TRPV4 increased PA contractility and raised PAP. Panx1-effluxed extracellular ATP signaled through purinergic P2Y2 receptor (P2Y2R) to activate protein kinase C (PKC), which in turn activated endothelial TRPV4 channels. Finally, caveolin-1 provided a signaling scaffold for endothelial Panx1, P2Y2R, PKC, and TRPV4 channels in PAs, promoting their spatial proximity and enabling signaling interactions. These results indicate that endothelial Panx1-P2Y2R-TRPV4 channel signaling, facilitated by caveolin-1, reduces PA contractility and lowers PAP.

biochemistry↗