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Pituitary adenylate cyclase‐activating polypeptide‐induced differentiation of embryonic neural stem cells into astrocytes is mediated via the β isoform of protein kinase C
Author(s) -
Watanabe Jun,
Ohba Motoi,
Ohno Fusako,
Kikuyama Sakae,
Nakamura Masahisa,
Nakaya Kazuyasu,
Arimura Akira,
Shioda Seiji,
Nakajo Shigeo
Publication year - 2006
Publication title -
journal of neuroscience research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.72
H-Index - 160
eISSN - 1097-4547
pISSN - 0360-4012
DOI - 10.1002/jnr.21065
Subject(s) - protein kinase c , phospholipase c , microbiology and biotechnology , biology , heterotrimeric g protein , protein kinase a , adenylate kinase , signal transduction , gq alpha subunit , gene isoform , g protein , kinase , chemistry , receptor , biochemistry , gene
We have found previously that pituitary adenylate cyclase‐activating polypeptide (PACAP) increases the number of astrocytes generated from cultured mouse neural stem cells (NSCs) via a mechanism that is independent of the cyclic AMP/protein kinase A pathway (Ohno et al., 2005). In the present study, the signaling pathway involved in the differentiation process was further investigated. PACAP‐induced differentiation was inhibited by the phospholipase C inhibitor, U73122, the protein kinase C (PKC) inhibitor, chelerythrine, and the intracellular calcium chelator, BAPTA‐AM, and was mimicked by phorbol 12‐myristate 13‐acetate (PMA), but not by 4α‐PMA. These results suggest that the PACAP‐generated signal was mediated via the PACAP receptor, PAC1 stimulated heterotrimeric G‐protein, resulting in activation of phospholipase C, followed by calcium‐ and phospholipid‐dependent protein kinase C (cPKC). To elucidate the involvement of the different isoforms of cPKC, their gene and protein expression were examined. Embryonic NSCs expressed α and βII PKC, but lacked PKCγ. When NSCs were exposed to 2 nM PACAP, protein expression levels of the βII isoform transiently increased two‐fold before differentiation, returning to basal levels by Day 4, whereas the level of PKCα increased linearly up to Day 6. Overexpression of PKCβII with adenovirus vector synergistically enhanced differentiation in the presence of 1 nM PACAP, whereas expression of the dominant‐negative mutant of PKCβII proved inhibitory. These results indicate that the β isoform of PKC plays a crucial role in the PACAP‐induced differentiation of mouse embryonic NSCs into astrocytes. © 2006 Wiley‐Liss, Inc.