Clock gene Per1 regulates the production of CCL2 and interleukin-6 through p38, JNK1 and NF-κB activation in spinal astrocytes.
It has been previously reported that spinal clock genes controlled under circadian rhythm contribute to the regulation of astrocytic function, which in turn is involved in diverse processes such as nociceptive transduction and the induction of inflammation. However, how clock genes expressed in spinal cord astrocytes are associated with the modulation of the inflammatory response is poorly understood. In the current study, the role of Period1 (Per1), one of clock genes, in the expression of chemokine (C-C motif) ligand 2 (CCL2) and interleukin-6 (IL-6), which are typical pro-inflammatory mediators produced by spinal astrocytes, was investigated. It was found that the knockdown of Per1 by using RNA interference led to a significant increase of the expression of CCL2 and IL-6 in cultured rat spinal astrocytes. Moreover, the silencing of the Per1 gene also increased the phosphorylation of p38, c-Jun N-terminal kinase (JNK) 1 and IκBα, and led to the translocation of p65 from the cytosol to the nucleus. The induction of CCL2 and IL-6 was significantly inhibited by treatment with the inhibitors of p38, JNK, and NF-κB. By contrast, the overexpression of PER1 by transfection vector significantly blocked the expression of CCL2 and IL-6, and the activation of p38, JNK, and NF-κB. Together, these results suggest that down-regulation of Per1 induced the phosphorylation of p38 and JNK1 and the subsequent activation of NF-κB, and that these events contribute to neuroinflammatory state in the spinal cord via the induction of the release of inflammatory mediators.
Department of Pharmacology, Hiroshima University Graduate School of Biomedical & Health Sciences, Kasumi 1-2-3, Minami-ku, Hiroshima 734-8553, Japan.
Tatsuhiko
T
Sugimoto
Department of Pharmacology, Hiroshima University Graduate School of Biomedical & Health Sciences, Kasumi 1-2-3, Minami-ku, Hiroshima 734-8553, Japan. Electronic address: mnori@hiroshima-u.ac.jp.
Norimitsu
N
Morioka
Department of Pharmacology, Hiroshima University Graduate School of Biomedical & Health Sciences, Kasumi 1-2-3, Minami-ku, Hiroshima 734-8553, Japan.
Fang Fang
FF
Zhang
Department of Pharmacology, Hiroshima University Graduate School of Biomedical & Health Sciences, Kasumi 1-2-3, Minami-ku, Hiroshima 734-8553, Japan.
Koichi
K
Sato
Department of Pharmacology, Hiroshima University Graduate School of Biomedical & Health Sciences, Kasumi 1-2-3, Minami-ku, Hiroshima 734-8553, Japan.
Hiromi
H
Abe
Department of Pharmacology, Hiroshima University Graduate School of Biomedical & Health Sciences, Kasumi 1-2-3, Minami-ku, Hiroshima 734-8553, Japan.
Kazue
K
Hisaoka-Nakashima
Department of Pharmacology, Hiroshima University Graduate School of Biomedical & Health Sciences, Kasumi 1-2-3, Minami-ku, Hiroshima 734-8553, Japan.
Yoshihiro
Y
Nakata
D021581:Active Transport, Cell Nucleus; D000818:Animals; D001253:Astrocytes / Q000166:cytology / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism; D018932:Chemokine CCL2 / Q000235:genetics / Q000378:metabolism*; D015850:Interleukin-6 / Q000378:metabolism*; D020935:MAP Kinase Signaling System; D048055:Mitogen-Activated Protein Kinase 8 / Q000037:antagonists & inhibitors / Q000378:metabolism; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000378:metabolism; D056950:Period Circadian Proteins / Q000235:genetics / Q000378:metabolism*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D013116:Spinal Cord / Q000166:cytology / Q000254:growth & development / Q000378:metabolism*; D019892:eIF-2 Kinase / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism
C491766:Ccl2 protein, rat; D018932:Chemokine CCL2; D015850:Interleukin-6; D016328:NF-kappa B; C539024:Per1 protein, rat; D056950:Period Circadian Proteins; D047428:Protein Kinase Inhibitors; D019892:eIF-2 Kinase; D048055:Mitogen-Activated Protein Kinase 8; D048051:p38 Mitogen-Activated Protein Kinases
CCL2; Clock gene; IL-6; Per1; Spinal astrocyte