Schwann cells (SCs) constitute a crucial element of the peripheral nervous system, by structurally supporting the formation of myelin and conveying vital trophic factors to the nervous system. However, the functions of SCs in developmental and regenerative stages remain unclear. Here, we investigated how optogenetic stimulation (OS) of SCs regulates their development. In SC monoculture, OS substantially enhanced SC proliferation and the number of BrdU + -S100ß + -SCs over time. In addition, OS also markedly promoted the expression of both Krox20 and myelin basic protein (MBP) in SC culture medium containing dBcAMP/NRG1, which induced differentiation. We found that the effects of OS are dependent on the intracellular Ca 2+ level. OS induces elevated intracellular Ca 2+ levels through the T-type voltage-gated calcium channel (VGCC) and mobilization of Ca 2+ from both inositol 1,4,5-trisphosphate (IP 3 )-sensitive stores and caffeine/ryanodine-sensitive stores. Furthermore, we confirmed that OS significantly increased expression levels of both Krox20 and MBP in SC-motor neuron (MN) coculture, which was notably prevented by pharmacological intervention with Ca 2+ . Taken together, our results demonstrate that OS of SCs increases the intracellular Ca 2+ level and can regulate proliferation, differentiation, and myelination, suggesting that OS of SCs may offer a new approach to the treatment of neurodegenerative disorders.
Bibliographical noteFunding Information:
This work was supported by the National Research Foundation of Korea (NRF-2018R1A2A1A05019550, NRF-2016R1A4A1010796), the Brain Korea 21 Plus Project in the Department of Mechanical and Aerospace Engineering, Seoul National University (F14SN02D1310), and the Korea Health Technology R&D Project through the Korea Health Industry Development Institute (KHIDI) funded by the Ministry of Health and Welfare (HI16C1012), Republic of South Korea. Confocal microscopy imaging was carried out at the Yonsei Advanced Imaging Center, Yonsei University College of Medicine, Seoul, South Korea.
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