Insulin and Insulin-Like Growth FactorType-I Up-Regulate the Vanilloid Receptor-1(TRPV1) in Stably TRPV1-ExpressingSH-SY5Y Neuroblastoma Cells
2007 (English)In: Journal of Neuroscience Research, ISSN 0360-4012, Vol. 85, no 7, 1413-1419 p.Article in journal (Refereed) Published
The capsaicin receptor, transient receptor potential, vanilloid type 1 (TRPV1), is a Ca2+ permeable ion channel activated by noxious stimuli eliciting pain. Several reports have shown modulation of TRPV1 activity and expression by neuronal growth factors. Here, we study the long-term effects on TRPV1 expression mediated by insulin like growth factor type-I (IGF-I) and insulin in a stably TRPV1-expressing SH-SY5Y neuroblastoma cell line. We show that after 72 h of 10 nM IGF-I or insulin exposure, the TRPV1 protein level was up-regulated 2.5 and 2-fold, respectively. By blocking phosphatidylinositol-3-kinase (PI(3)K) or mitogen-activated protein kinase (MAPK) signaling we concluded that the increase in total TRPV1 protein content induced by IGF-I was controlled by PI(3)K signaling whereas insulin seemed to regulate TRPV1 protein expression via both PI(3)K and MAPK pathways. Inhibiting protein kinase C (PKC) blocked the effects of both IGF-I and insulin. Furthermore, the concentrations causing 50 % Ca2+ increase (EC50) after insulin and IGF-I-treatments were significantly lowered compared to untreated cells. We conclude that IGF-I and insulin enhance TRPV1 protein expression and activity, and impaired pain sensation might result from distorted TRPV1 regulation in the peripheral nervous system.
Place, publisher, year, edition, pages
2007. Vol. 85, no 7, 1413-1419 p.
IdentifiersURN: urn:nbn:se:su:diva-30176DOI: 10.1002/jnr.21255ISI: 000246929900005OAI: oai:DiVA.org:su-30176DiVA: diva2:241950