Brain-derived Neurotrophic Factor (BDNF) Induces Sustained Intracellular Ca2+ Elevation through the Up-regulation of Surface Transient Receptor Potential 3 (TRPC3) Channels in Rodent Microglia

• Published in: The Journal of biological chemistry 2014-06, Vol.289 (26), p.18549-18555
• Main Authors: Mizoguchi, Yoshito, Kato, Takahiro A., Seki, Yoshihiro, Ohgidani, Masahiro, Sagata, Noriaki, Horikawa, Hideki, Yamauchi, Yusuke, Sato-Kasai, Mina, Hayakawa, Kohei, Inoue, Ryuji, Kanba, Shigenobu, Monji, Akira
• Format: Article
• Language: English
• Subjects: Animals; Brain-derived Neurotrophic Factor (BDNF); Brain-Derived Neurotrophic Factor - genetics; Brain-Derived Neurotrophic Factor - metabolism; Calcium; Calcium - metabolism; Cells, Cultured; Immunology; Microglia; Microglia - metabolism; Nitric Oxide; Rats; Rats, Sprague-Dawley; Transient Receptor Potential Channels (TRP Channels); TRPC Cation Channels - genetics; TRPC Cation Channels - metabolism; Up-Regulation
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M114.555334

Microglia are immune cells that release factors, including proinflammatory cytokines, nitric oxide (NO), and neurotrophins, following activation after disturbance in the brain. Elevation of intracellular Ca2+ concentration ([Ca2+]i) is important for microglial functions such as the release of cytokines and NO from activated microglia. There is increasing evidence suggesting that pathophysiology of neuropsychiatric disorders is related to the inflammatory responses mediated by microglia. Brain-derived neurotrophic factor (BDNF) is a neurotrophin well known for its roles in the activation of microglia as well as in pathophysiology and/or treatment of neuropsychiatric disorders. In this study, we sought to examine the underlying mechanism of BDNF-induced sustained increase in [Ca2+]i in rodent microglial cells. We observed that canonical transient receptor potential 3 (TRPC3) channels contribute to the maintenance of BDNF-induced sustained intracellular Ca2+ elevation. Immunocytochemical technique and flow cytometry also revealed that BDNF rapidly up-regulated the surface expression of TRPC3 channels in rodent microglial cells. In addition, pretreatment with BDNF suppressed the production of NO induced by tumor necrosis factor α (TNFα), which was prevented by co-adiministration of a selective TRPC3 inhibitor. These suggest that BDNF induces sustained intracellular Ca2+ elevation through the up-regulation of surface TRPC3 channels and TRPC3 channels could be important for the BDNF-induced suppression of the NO production in activated microglia. We show that TRPC3 channels could also play important roles in microglial functions, which might be important for the regulation of inflammatory responses and may also be involved in the pathophysiology and/or the treatment of neuropsychiatric disorders. Background: BDNF and Ca2+ mobilization is important for microglial function. Results: We showed BDNF elevates intracellular Ca2+ through TRPC3 channels. Conclusion: TRPC3 is important for BDNF suppression of microglial activation. Significance: TRPC3 might be important for the treatment of psychiatric disorders.