Activation of JAK-STAT3 signaling pathway in chronic subdural hematoma outer membranes

• Published in: Neuroscience letters 2013-02, Vol.534, p.166-170
• Main Authors: Osuka, Koji, Watanabe, Yasuo, Usuda, Nobuteru, Atsuzawa, Kimie, Shima, Hiroshi, Takeuchi, Mikinobu, Yasuda, Muneyoshi, Takayasu, Masakazu
• Format: Article
• Language: English
• Subjects: Aged; Chronic subdural hematoma; Female; Fibroblasts - metabolism; Hematoma, Subdural, Chronic - metabolism; Hematoma, Subdural, Chronic - pathology; Humans; Interleukin-6; Interleukin-6 - metabolism; Janus kinase; Janus Kinase 1 - metabolism; Janus Kinases - metabolism; Male; Middle Aged; Signal transducer and activator of transcription; Signal Transduction; STAT1 Transcription Factor - metabolism; STAT3 Transcription Factor - metabolism
• ISSN: 0304-3940; 1872-7972
• DOI: 10.1016/j.neulet.2012.11.011

► We examine concentration of IL-6 in hematoma fluid of CSDH. ► We also explore expressions of JAK1, STAT1 and STAT3 in outer membrane of CSDH. ► IL-6 increases in hematoma fluid of CSDH. ► STAT3 is dominantly expressed in fibroblasts compared with STAT1. ► Activation of JAK-STAT3 signaling pathway by IL-6 involves the growth of CSDH. Chronic subdural hematoma (CSDH) is an inflammatory disease, the mechanism of which still remains to be elucidated. Interleukin-6 (IL-6), one of the inflammatory cytokines regulating janus kinase (JAK)-signal transducer and activator of transcription (STAT) signaling pathway, is expressed in human CSDH fluid. The status of this signaling pathway in human CSDH outer membranes was examined in the present study using outer membranes obtained during trepanation surgery. Concentrations of IL-6 in human CSDH fluids were measured using an enzyme immuno-assay kit. Expression patterns of JAK1, STAT1, phosphorylated (p)-STAT1 at Tyr701 and at Ser727, STAT3, p-STAT3 at Tyr705 and at Ser727 and actin in outer membranes were examined by Western blot analysis and immunohistochemistry. IL-6 is significantly expressed in human CSDH fluids compared with control cerebrospinal fluid. JAK1, STAT1 and STAT3 were detected in all cases. The expression of p-STAT3 at Tyr705 is more significant compared with that of p-STAT1 at Tyr701. In some cases, p-STAT3 at Ser727 could also be detected, while p-STAT1 at Ser727 could not. The localizations of STAT1 and STAT3 were revealed to be present in fibroblasts in human CSDH outer membranes, especially when p-STAT3 at Tyr705 was in the nuclei of fibroblasts. These findings suggest that JAK1-STAT3 signaling is dominantly activated in fibroblasts of human CSDH outer membranes compared with STAT1 and indicate the possibility that this JAK1-STAT3 pathway might be activated by IL-6 and play a critical role in progression of human CSDH.