Effect of Phoneutria nigriventer Venom on the Expression of Junctional Protein and P-gp Efflux Pump Function in the Blood-Brain Barrier

Author(s)

Raposo, Catarina ^[1] ; Miranda Odorissi, Paulo Alexandre ^[1] ; Oliveira, Alexandre L. R. ^[2] ; Aoyama, Hiroshi ^[3] ; Ferreira, Carmen Verissima ^[3] ; Verinaud, Liana ^[2] ; Fontana, Karina ^[4] ; Ruela-de-Sousa, Roberta R. ^[3] ; da Cruz-Hoefling, Maria Alice ^[1]

Affiliation

^[1] Univ Estadual Campinas UNICAMP, Dept Histol & Embriol, Inst Biol, BR-13087130 Campinas, SP - Brazil

^[2] Univ Estadual Campinas UNICAMP, Dept Biol Estrutural & Func, Inst Biol, BR-13087130 Campinas, SP - Brazil

^[3] Univ Estadual Campinas UNICAMP, Dept Bioquim, Inst Biol, BR-13087130 Campinas, SP - Brazil

^[4] Univ Estadual Campinas UNICAMP, Dept Farmacol, Fac Ciencias Med, BR-13087130 Campinas, SP - Brazil

• Document type: Journal article
• Source: Neurochemical Research; v. 37, n. 9, p. 1967-1981, SEP 2012.
• Web of Science Citations: 20

Abstract

Phoneutria nigriventer spider venom (PNV) contains Ca2+, K+ and Na+ channel-acting peptides that affect neurotransmitter release and causes excitotoxicity in PNS and CNS. It has been demonstrated that PNV causes blood-brain barrier (BBB) breakdown of hippocampal microvessels time-dependently through enhanced microtubule-mediated vesicular transport. Herein, it is hypothesized that PNV can cause BBB breakdown in the hippocampus and cerebellum time-dependently through other molecular mechanisms. The BBB integrity was assessed through the analysis of expression of Poly-glycoprotein (P-gp) efflux transporter protein, laminin from basement membrane and endothelial tight junctional and adhesion junctional (TJ/AJ) proteins. Phosphatase and tensin homolog (PTEN) and protein phosphatase 2A (PP2A) expression, which are known to have a role in the phosphorylation of junctional proteins and BBB opening, were also investigated. Astrocytes P-gp activity was determined by flow cytometry. The study demonstrated temporary decreased expression of laminin, TJ and AJ proteins (ZO1//occludin//claudin-5//beta-catenin) and P-gp (more prominently in hippocampus), which was completely or partially resolved between 2 and 5 h (and more quickly for cerebellum). PNV inhibited P-gp activity in astrocytes. PP2A phosphorylation, which inhibits the enzyme activity, was increased in both regions (15-45 min); however the phosphorylation level returned to baseline after 2 h. In conclusion, PNV disrupts paracellular transport in the BBB and possesses substrates for the active P-gp efflux transporter located in the BBB complex. Further studies into cellular mechanisms of astrocyte/endothelial interactions, using PNV as tool, may identify how astrocytes regulate the BBB, a characteristic that may be useful for the temporary opening of the BBB. (AU)