A plasma membrane-localized polycystin-1/polycystin-2 complex in endothelial cells elicits vasodilation

Abstract

Polycystin-1 (PC-1, PKD1), a receptor-like protein expressed by the Pkd1 gene, is present in a wide variety of cell types, but its cellular location, signaling mechanisms and physiological functions are poorly understood. Here, by studying tamoxifen-inducible, endothelial cell (EC)-specific Pkd1 knockout (Pkd1 ecKO) mice, we show that flow activates PC-1-mediated, Ca2+-dependent cation currents in ECs. EC-specific PC-1 knockout attenuates flow-mediated arterial hyperpolarization and vasodilation. PC-1-dependent vasodilation occurs over the entire functional shear stress range and via the activation of endothelial nitric oxide synthase (eNOS) and intermediate (IK)- and small (SK)-conductance Ca2+-activated K+ channels. EC-specific PC-1 knockout increases systemic blood pressure without altering kidney anatomy. PC-1 coimmunoprecipitates with polycystin-2 (PC-2, PKD2), a TRP polycystin channel, and clusters of both proteins locate in nanoscale proximity in the EC plasma membrane. Knockout of either PC-1 or PC-2 (Pkd2 ecKO mice) abolishes surface clusters of both PC-1 and PC-2 in ECs. Single knockout of PC-1 or PC-2 or double knockout of PC-1 and PC-2 (Pkd1/Pkd2 ecKO mice) similarly attenuates flow-mediated vasodilation. Flow stimulates non-selective cation currents in ECs that are similarly inhibited by either PC-1 or PC-2 knockout or by interference peptides corresponding to the C-terminus coiled-coil domains present in PC-1 or PC-2. In summary, we show that PC-1 regulates arterial contractility through the formation of an interdependent signaling complex with PC-2 in endothelial cells. Flow stimulates PC-1/PC-2 clusters in the EC plasma membrane, leading to eNOS, IK channel and SK channel activation, vasodilation and a reduction in blood pressure.

Vasodilators activate the anion channel TMEM16A in endothelial cells to reduce blood pressure

“…These data indicate that clusters observed in TMEM16A ecKO cells are due to background labeling of TMEM16A antibodies, validating the data obtained in TMEM16A fl/fl endothelial cells (Fig. 3A) ( 32 ). Moreover, these results demonstrate that surface TMEM16A and TRPV4 clusters locate in nanoscale proximity, with a sizable proportion exhibiting overlap in the endothelial cell plasma membrane.…”

“…Mechanical stimulation with a fluid stream activates a Cl − current in cultured human aortic endothelial cells, although the molecular identity of the channels involved was not determined ( 37 ). Flow stimulates a protein complex composed of polycystin 1 (PKD1) and PKD2 in endothelial cells, leading to eNOS, SK, and IK channel activation and vasodilation ( 4 , 32 ). Flow also stimulates Piezo1, a Ca 2+ -permeant nonselective cation channel, in both arterial and capillary endothelial cells ( 38 , 39 ).…”

The GPCR properties of polycystin-1- A new paradigm

“…Studies in transfected CHO cells revealed unique, PC1 and PC2 co-dependent, calcium-permeable cation currents (Hanaoka et al, 2000). However, the idea of a joint ion channel function for these two proteins did not become widely recognized until the ability of PC1/PC2 to sense fluid shear stress and modulate intracellular calcium levels was demonstrated in cells (Nauli et al, 2003;Alenghat et al, 2004;Nauli et al, 2008;MacKay et al, 2022). Most recently, endothelial cell-specific Pkd1 and Pkd2 knockout mice were used to demonstrate regulation of vasodilation by the PC1/ PC2 complex (MacKay et al, 2022).…”

“…However, the idea of a joint ion channel function for these two proteins did not become widely recognized until the ability of PC1/PC2 to sense fluid shear stress and modulate intracellular calcium levels was demonstrated in cells (Nauli et al, 2003;Alenghat et al, 2004;Nauli et al, 2008;MacKay et al, 2022). Most recently, endothelial cell-specific Pkd1 and Pkd2 knockout mice were used to demonstrate regulation of vasodilation by the PC1/ PC2 complex (MacKay et al, 2022). Formation of an ion channel-like structure consisting of PC1 and PC2 was finally validated by solving the molecular structure of the membraneassociated portions of the two proteins together (Su et al, 2018).…”

Review of the Use of Animal Models of Human Polycystic Kidney Disease for the Evaluation of Experimental Therapeutic Modalities

“…PKD1 and PKD2 encode Polycystin-1 (PC-1) and Polycystin-2 (PC-2/TRPP2), respectively. PC-1, which functions as a mechanosensor of intraluminal fluid flow, interacts with PC-2/TRPP2, which has calcium (Ca 2+ ) channel activity in its C-terminus [ 12 ]. The PKHD1 gene product fibrocystin/polyductin (FPC) has a long extracellular domain and interacts with the N-terminus of PC-2 [ 13 ].…”