Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland.
Cell Calcium. 2012 Dec;52(6):468-80. doi: 10.1016/j.ceca.2012.08.005. Epub 2012 Oct 4.
TRPV6, a highly calcium-selective member of the transient receptor potential (TRP) channel superfamily, is a major pathway for calcium absorption in the fetal and adult body. It is expressed abundantly in the duodenum, the placenta and exocrine tissues. TRVP6 was postulated to contribute to store-operated calcium channel (SOC) activity in certain cell types such as exocrine cells. In this study, we tested 2-APB, a widely used SOC inhibitor on human TRPV6 (hTRPV6) activity using fluorescence imaging, patch clamp and radioactive tracer techniques in transiently and stably transfected HEK293 cells. We found that the basal calcium and cadmium influx was higher in HEK293 cells transfected with hTRPV6 than in non-transfected cells. 2-APB inhibited hTRPV6 activity in both transient and stably transfected cells. This effect was slightly sensitive toward extracellular calcium. The extracellular sodium concentration did not affect the inhibition of hTRPV6 by 2-APB. However, N-methyl-d-glucamine significantly diminished the inhibitory effect of 2-APB presumably through direct interaction with this compound. Furthermore, 2-APB inhibited the activity of TRPV6 orthologs but not human TRPV5. 2-APB may serve as a parental compound for the development of therapeutic strategies specifically targeting the hTRPV6 calcium channel.
瞬时受体电位（TRP）通道超家族中的 TRPV6 是一种高度钙选择性成员，是胎儿和成人身体中钙吸收的主要途径。它在十二指肠、胎盘和外分泌组织中大量表达。TRPV6 被假设为某些细胞类型（如外分泌细胞）中的储存操纵钙通道（SOC）活性的贡献者。在这项研究中，我们使用荧光成像、膜片钳和放射性示踪技术，在瞬时和稳定转染的 HEK293 细胞中测试了 2-APB，一种广泛用于 SOC 抑制剂的 TRPV6（hTRPV6）活性。我们发现，与未转染细胞相比，转染 hTRPV6 的 HEK293 细胞中的基础钙和镉内流更高。2-APB 抑制瞬时和稳定转染细胞中的 hTRPV6 活性。这种作用对细胞外钙稍微敏感。细胞外钠浓度不会影响 2-APB 对 hTRPV6 的抑制作用。然而，N-甲基-D-葡萄糖胺通过与该化合物直接相互作用，显著减弱了 2-APB 的抑制作用。此外，2-APB 抑制 TRPV6 同源物的活性，但不抑制人 TRPV5。2-APB 可能作为专门针对 hTRPV6 钙通道的治疗策略的母体化合物。
