Caveolin-1 mediates positive cooperativity between P2Y2 and P2X7 receptors and the pro-adhesive endothelial phenotype in schistosomiasis

Schistosomiasis is a mesenteric intravascular disease caused by Schistosoma worms [Nat. Rev. Dis. Primers (2018) 4:13], and Sm-p40 is a major egg soluble antigen. Endothelial damage promotes ATP release, an agonist of purinergic P2Y₂ (P2Y₂R) and P2X7 (P2X7R) receptors expressed on the endothelium [Front. Pharmacol. (2017) 8:661]. We showed that, in the infected group, cooperativity of endothelial P2Y₂R and P2X7R promotes greater monocyte adhesion to the endothelial monolayer than isolated receptor stimulation [Front. Immunol. (2024) 14:1328897]. However, the roles of Caveolin-1 (Cav-1), the main structural protein of caveolae [Physiol. Rev. (2004) 84:1341], in the P2Y₂R/P2X7R signaling and of Sm−p40 in the endothelial phenotype remain unknown. Mesenteric endothelial cells (MECs) from control and S. mansoni-infected mice (55-75 d.p.i.; CEUA A07/26−124−22) were transfected with Cav−1 siRNA (1 pmol) or not (48h). MECs were stimulated with 100 µM UTP (5h), 500 µM ATP (10 min), or UTP + ATP. Control MECs were pretreated with Sm−p40 (1 µg/mL; 1h) before purinergic stimulation. Monocyte adhesion (10⁴/well; 30 min) was quantified by optical microscopy. Cav−1 silencing reduced Cav−1 expression by ~70% in both control and infected groups (5.1 ± 0.8 to 1.6 ± 0.4 and 4.3 ± 0.6 to 1.0 ± 0.1 a.u., respectively). In the control group, Cav−1 silencing did not alter adhesion. In the infected group, Cav−1 silencing reduced UTP + ATP-induced adhesion (5.4 ± 0.3 cells) compared with Cav−1 presence (11.2 ± 1.2; p<0.0001). In Sm−p40-treated MECs, Cav−1 silencing reduced antigen-induced adhesion (4.3 ± 0.3) compared with basal (6.5 ± 0.3; p<0.0001). These results suggest that Cav−1 mediates positive cooperativity between P2Y₂R/P2X7R and contributes to the pro-adhesive MEC phenotype in schistosomiasis, promoting leukocyte adhesion and mesenteric inflammation. Support: CNPq, FAPERJ, PIBIC, CAPES, INCT "Sinalização Purinérgica: Desafios para a Saúde do Século XXI", CNPq 409156/2024-8.