Inhibition of JAK2/STAT3 to ameliorate early brain injury following subarachnoid hemorrhage through downregulating expression and nuclear translocation of high mobility group box 1
10.3760/cma.j.issn.1671-8925.2018.04.006
- VernacularTitle:抑制JAK2/STAT3下调HMGB1表达及核转位减轻蛛网膜下腔出血后早期脑损伤
- Author:
Jiyang AN
1
;
Honggang PANG
;
Jinning SONG
Author Information
1. 郑州大学第一附属医院神经外科
- Keywords:
Subarachnoid hemorrhage;
Early brain injury;
High mobility group box 1
- From:
Chinese Journal of Neuromedicine
2018;17(4):356-363
- CountryChina
- Language:Chinese
-
Abstract:
Objective To investigate the role of JAK2/STAT3 signaling pathway in regulating the expression and nuclear-cytoplasm translocation of high mobility group box 1 (HMGB1) in early brain injury (EBI) after subarachnoid hemorrhage (SAH).Methods Ninety SD rats were divided into a sham group (15 rats),an SAH group (altogether 45 rats,with 15 ones for each time point of 6 h,1 d,and 3 d),an SAH+AG490 (JAK2/STAT3 inhibitor) group (15 rats) and an SAH+dimethyl sulfoxide (DMSO)group (15 rats).The SAH models in the later 3 groups were established by endovascular perforation;the blood vessels were not perforated in the sham group but the other operations were the same as in the SAH groups.(1) Western blotting was used to detect the expression of HMGB1 and phosphorylated JAK2/STAT3 (p-JAK2/p-STAT3) in the 4 groups (at different time points in the SAH group) and compared the expression changes between the 4 groups after AG490 intervention.(2)Immunofluorescence confocal microscopy was used to detect HMGB1 nuclear translocation in the 4 groups.(3) TUNEL staining was used to detect apoptosis in the 4 groups.(4) Brain water contents and neurobehavioral scores in the 4 groups were measured.Results (1) Western blotting showed that the expression levels ofp-JAK2 and p-STAT3 were significantly increased at 6 h,1 d,and 3 d after SAH,and there were significant differences between the sham group and the SAH group (P＜0.05).HMGB1 total protein,cytoplasmic HMGB1 and nucleus HMGB1 also increased significantly at different time points after SAH,and statistically significant differences existed between the sham group and the SAH group (P＜0.05).The expression levels ofp-JAK2/p-STAT3,HMGB1 and cytoplasm and nucleus HMGB1 in the SAH+AG490 group were significantly lower than in the SAH group and SAH+DMSO group(P＜0.05).(2) The immunofluorescence staining showed that HMGB1 staining was positive in the SAH group while the positive staining of HMGB1 was present mainly in the nucleus but not in the cytoplasm in the sham and SAH+AG490 groups,suggesting that AG490 might inhibit the nucleus-cytoplasm transposition of HMGB1.(3) Compared with the SAH and SAH+DMSO groups,the TUNEL staining positive cells in the SAH+AG490 group were significantly decreased (P＜0.05).(4) Compared with the SAH and SAH+DMSO groups,the brain water contents in the SAH+AG490 group decreased significantly and the neurobehavioral scores increased significantly (P＜0.05).Conclusions JAK2/STAT3 signaling pathway is involved in the pathological process of early brain injury after SAH,and its mechanism may be related to the regulation of HMGB1 expression and nuclear-cytoplasm transposition.The regulation of JAK2/STAT3 may contribute to the neuroprotection dependent of HMGB 1.
