{Reference Type}: Journal Article
{Title}: Cavβ3 Contributes to the Maintenance of the Blood-Brain Barrier and Alleviates Symptoms of Experimental Autoimmune Encephalitis.
{Author}: Martus D;Williams SK;Pichi K;Mannebach-Götz S;Kaiser N;Wardas B;Fecher-Trost C;Meyer MR;Schmitz F;Beck A;Fairless R;Diem R;Flockerzi V;Belkacemi A;
{Journal}: Arterioscler Thromb Vasc Biol
{Volume}: 0
{Issue}: 0
{Year}: 2024 Jul 3
{Factor}: 10.514
{DOI}: 10.1161/ATVBAHA.124.321141
{Abstract}: <B>UNASSIGNED: </B>Tight control of cytoplasmic Ca2+ in endothelial cells is essential for the regulation of endothelial barrier function. Here, we investigated the role of Cavβ3, a subunit of voltage-gated Ca2+ (Cav) channels, in modulating Ca2+ signaling in brain microvascular endothelial cells (BMECs) and how this contributes to the integrity of the blood-brain barrier.<BR><B>UNASSIGNED: </B>We investigated the function of Cavβ3 in BMECs by Ca2+ imaging and Western blot, examined the endothelial barrier function in vitro and the integrity of the blood-brain barrier in vivo, and evaluated disease course after induction of experimental autoimmune encephalomyelitis in mice using Cavβ3-/- (Cav β3-deficient) mice as controls.<BR><B>UNASSIGNED: </B>We identified Cavβ3 protein in BMECs, but electrophysiological recordings did not reveal significant Cav channel activity. In vivo, blood-brain barrier integrity was reduced in the absence of Cavβ3. After induction of experimental autoimmune encephalomyelitis, Cavβ3-/- mice showed earlier disease onset with exacerbated clinical disability and increased T-cell infiltration. In vitro, the transendothelial resistance of Cavβ3-/- BMEC monolayers was lower than that of wild-type BMEC monolayers, and the organization of the junctional protein ZO-1 (zona occludens-1) was impaired. Thrombin stimulates inositol 1,4,5-trisphosphate-dependent Ca2+ release, which facilitates cell contraction and enhances endothelial barrier permeability via Ca2+-dependent phosphorylation of MLC (myosin light chain). These effects were more pronounced in Cavβ3-/- than in wild-type BMECs, whereas the differences were abolished in the presence of the MLCK (MLC kinase) inhibitor ML-7. Expression of Cacnb3 cDNA in Cavβ3-/- BMECs restored the wild-type phenotype. Coimmunoprecipitation and mass spectrometry demonstrated the association of Cavβ3 with inositol 1,4,5-trisphosphate receptor proteins.<BR><B>UNASSIGNED: </B>Independent of its function as a subunit of Cav channels, Cavβ3 interacts with the inositol 1,4,5-trisphosphate receptor and is involved in the tight control of cytoplasmic Ca2+ and Ca2+-dependent MLC phosphorylation in BMECs, and this role of Cavβ3 in BMECs contributes to blood-brain barrier integrity and attenuates the severity of experimental autoimmune encephalomyelitis disease.