PT  - JOURNAL ARTICLE
AU  - Olivia Molinar-Inglis
AU  - Cierra A. Birch
AU  - Dequina Nicholas
AU  - Metztli Cisneros-Aguirre
AU  - Anand Patwardhan
AU  - Buxin Chen
AU  - Neil J. Grimsey
AU  - Patrick K. Gomez Menzies
AU  - Huilan Lin
AU  - Luisa J. Coronel
AU  - Mark A. Lawson
AU  - Hemal. H. Patel
AU  - JoAnn Trejo
TI  - aPC/PAR1 confers endothelial anti-apoptotic activity via a discrete β-arrestin-2 mediated SphK1-S1PR1-Akt signaling axis
AID  - 10.1101/2021.03.27.437291
DP  - 2021 Jan 01
TA  - bioRxiv
PG  - 2021.03.27.437291
4099  - http://biorxiv.org/content/early/2021/04/14/2021.03.27.437291.short
4100  - http://biorxiv.org/content/early/2021/04/14/2021.03.27.437291.full
AB  - Endothelial dysfunction is associated with multiple vascular diseases and lacks effective treatments. Activated Protein C (aPC) is a promising biotherapeutic that signals via protease-activated receptor-1 (PAR1) to promote diverse cytoprotective responses, including endothelial barrier stabilization, anti-inflammatory and anti-apoptotic activities, which is facilitated by co-receptors. We showed that aPC-activated PAR1 signals preferentially via β-arrestin-2 (β-arr2) and dishevelled-2 (Dvl2) scaffolds rather than G proteins to enhance barrier protection. However, the mechanisms by which aPC/PAR1 promotes other cytoprotective responses are poorly understood. Here we define a novel β-arr2-mediated sphingosine kinase-1 (SphK1)-sphingosine-1-phosphate receptor-1 (S1PR1)-Akt signaling axis that confers aPC/PAR1-mediated protection against cell death. We show that PAR1 and S1PR1 co-exist in caveolin-1-rich microdomains basally and aPC markedly increases S1PR1-caveolin-1 co-association. Moreover, aPC stimulates β-arr2-dependent SphK1 activation independent of Dvl2, which is critical for S1PR1 transactivation. These studies reveal that different aPC/PAR1 cytoprotective responses are mediated by discrete β-arr2-driven signaling pathways in caveolae.Competing Interest StatementThe authors have declared no competing interest.