2-B-P-014 〇横谷 みき¹、髙田 芙友子¹、岩尾 卓朗¹、松本 純一¹、安永 美保¹、有留 尚孝¹、佐野 和憲²、道具 伸也¹ Yokoya Miki¹, Fuyuko Takata¹, Takuro Iwao¹, Junichi Matsumoto¹, Miho Yasunaga¹, Hisataka Aridome¹, Kazunori Sano², Shinya Dohgu^{1 1}福岡大・薬・応用薬剤学、²福岡大・薬・生体機能制御学 ¹Dept. Pharmaceut. Care & Health Sci., Fac. Pharmaceut. Sci., Fukuoka Univ.,, ²Dept. Physiol. & Pharmacol., Fac. Pharmaceut. Sci., Fukuoka Univ. Parkinson's disease (PD) is characterized by widespread distribution of Lewy bodies, which are mainly composed of aggregated α-synuclein(α-Syn), in the brain. We previously revealed that pericytes, one of the blood-brain barrier-constituting cells, take up α-Syn and degrade it. Therefore, an efficient uptake of a-Syn by pericytes enable to establish a novel disease modifying therapy of PD utilizing the α-Syn d　egradation system in pericytes. In this study, we investigated the intracellular uptake mechanism in pericytes for α-Syn.
We used primary cultures of rat brain pericytes. Increasing concentrations of extracellular α-Syn ranging from 0.05 to 10 μg/mL resulted in the increased cellular accumulation of α-Syn in pericytes. The cell/medium ratio of α-Syn in pericytes showed a significant decrease with the increased concentration of extracellular α-Syn. Furthermore, the uptake of α-Syn by pericytes was decreased at 4˚C and in the presence of chlorpromazine. Cyclosporin A(CsA), a P-glycoprotein (P-gp) inhibitor, increased the uptake of α-Syn by pericytes. However, siRNA-mediated knockdown of P-gp failed to increase the uptake of α-Syn by pericytes. Knockdown of cyclophillin A (CypA), a molecular target of CsA to inhibit calcineurin activity, decreased the uptake of α-Syn by pericytes.
These results suggest that α-Syn uptake by pericytes is mediated by saturable transport system, clathrin-mediated endocytosis, and a CypA-dependent mechanism. In addition, inhibiting calcineurin activity would contribute to the enhanced α-Syn uptake, leading to α-Syn degradation by pericytes.