Involvement of the JAK-STAT pathway and SOCS3 in the regulation of adiponectin-generated reactive oxygen species in murine macrophage RAW 264 cells.
Adiponectin is a protein hormone produced by differentiating adipocytes and has been proposed to have anti-diabetic and immunosuppressive properties. We previously reported that the globular form of adiponectin (gAd) induces the generation of reactive oxygen species (ROS) and nitric oxide (NO), followed by caspase-dependent apoptotic cell death in RAW 264 cells. Here, we demonstrate that gAd-induced ROS generation and apoptosis were diminished by suppressor of cytokine signaling 3 (SOCS3). The phosphorylation level of signal transducer and activator of transcription (STAT) 3 detected by Western blotting was highest at 20 min in gAd-treated RAW 264 cells. This phosphorylation was inhibited by AG490, a specific inhibitor of janus-activator kinase (JAK). The gAd-induced ROS and NO were reduced by administration of AG490 and Jak-2-specific siRNA in RAW 264 cells. The gAd stimulation transiently induced SOCS3 mRNA expression and protein production. We examined SOCS3-overexpressing RAW 264 cells to investigate the role of the JAK-STAT pathway in gAd-induced ROS and NO generation. SOCS3 overexpression significantly reduced both ROS and NO generation. Additionally, gAd-induced caspase activation and apoptotic cell death were reduced in SOCS3 transfectants compared with vector control transfectants. These results suggest that the JAK-STAT pathway, which can be suppressed by SOCS3 expression, is involved in gAd-induced ROS and NO generation followed by apoptotic cell death.
Akifusa
Sumio
S
Faculty of Dental Science, Kyushu University, Fukuoka, Japan. akifusa@dent.kyushu-u.ac.jp
Kamio
Noriaki
N
Shimazaki
Yoshihiro
Y
Yamaguchi
Noboru
N
Nonaka
Kazuaki
K
Yamashita
Yoshihisa
Y
D052242:Adiponectin / Q000378:metabolism*; D000818:Animals; D017209:Apoptosis; D002460:Cell Line; D053612:Janus Kinases / Q000378:metabolism*; D008264:Macrophages / Q000378:metabolism*; D051379:Mice; D009569:Nitric Oxide / Q000378:metabolism; D010766:Phosphorylation; D012333:RNA, Messenger / Q000032:analysis; D017382:Reactive Oxygen Species / Q000378:metabolism*; D050791:STAT Transcription Factors / Q000378:metabolism; D015398:Signal Transduction; D000071223:Suppressor of Cytokine Signaling 3 Protein; D050826:Suppressor of Cytokine Signaling Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*
D052242:Adiponectin; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D050791:STAT Transcription Factors; C491411:Socs3 protein, mouse; D000071223:Suppressor of Cytokine Signaling 3 Protein; D050826:Suppressor of Cytokine Signaling Proteins; D009569:Nitric Oxide; D053612:Janus Kinases