Division of Cardiovascular Surgery, Department of Surgery, Tri-Service General Hospital, National Defense Medical Center, 114 Taipei, Taiwan.
Exp Biol Med (Maywood). 2011 Oct;236(10):1156-65. doi: 10.1258/ebm.2011.011060. Epub 2011 Sep 5.
Hepatocytes are one of the important targets in dengue virus (DV) infection. Chemokines produced in DV infection play important immunopathogenic roles. We previously showed that DV infection can directly activate signal transducer and activator of transcription 3 (STAT3) in dendritic cells. In the present study, we examined the possible involvement of the Janus kinase (JAK)/STAT3 pathway in chemokine production from DV-infected hepatocytes. HepG2 cells were infected by DV. The activation of STAT3, nuclear factor-kappaB (NF-κB) and other transcription factors was determined by Western blotting or electrophoretic mobility shift assay. The concentrations of chemokines were measured by enzyme-linked immunosorbent assay. Virus titers were determined by plaque assays. A genetic manipulation with short hairpin RNA (shRNA) was applied to knock-down STAT3. Chemotaxis assays were used to evaluate cell migration. We observed that DV infection induced phosphorylation of STAT3 and its DNA-binding activity and such effects were attenuated by the inhibitor of JAK2 or JAK3. Blocking JAK2 or JAK3 reduced DV-induced cell migration and production of chemokines like interleukin-8 and regulated upon activation, normal T-cell expressed and secreted (RANTES). At high doses, the JAK2 but not JAK3 inhibitor could significantly inhibit DV production. Knocking down STAT3 with shRNA suppressed DV-induced STAT3, NF-κB and AP-1 activation. Furthermore, reduction of STAT3 suppressed DV-induced chemokine production and cell migration but had no effect on virus production. In conclusion, the results show that the JAK/STAT3 pathway is critical in chemokine production from DV-infected hepatocytes. Targeting this pathway may be of benefit in the therapy of DV-induced immunopathologies.
肝细胞是登革病毒（DV）感染的重要靶标之一。DV 感染中产生的趋化因子在免疫发病机制中发挥重要作用。我们之前的研究表明，DV 感染可以直接激活树突状细胞中的信号转导子和转录激活子 3（STAT3）。在本研究中，我们研究了 JAK/STAT3 通路在 DV 感染的肝细胞中产生趋化因子的可能参与。用 DV 感染 HepG2 细胞。通过 Western blot 或电泳迁移率变动分析测定 STAT3、核因子-κB（NF-κB）和其他转录因子的激活。通过酶联免疫吸附试验测定趋化因子的浓度。通过噬菌斑测定法测定病毒滴度。应用短发夹 RNA（shRNA）的遗传操作来敲低 STAT3。用趋化性测定来评估细胞迁移。我们观察到，DV 感染诱导 STAT3 的磷酸化及其 DNA 结合活性，并且 JAK2 或 JAK3 的抑制剂减弱了这种作用。阻断 JAK2 或 JAK3 减少了 DV 诱导的细胞迁移和趋化因子如白细胞介素-8 和活化正常 T 细胞表达和分泌（RANTES）的产生。在高剂量下，JAK2 但不是 JAK3 抑制剂可显著抑制 DV 的产生。用 shRNA 敲低 STAT3 抑制了 DV 诱导的 STAT3、NF-κB 和 AP-1 激活。此外，STAT3 的减少抑制了 DV 诱导的趋化因子产生和细胞迁移，但对病毒产生没有影响。总之，结果表明 JAK/STAT3 通路在 DV 感染的肝细胞中产生趋化因子中是关键的。靶向该通路可能有益于 DV 诱导的免疫病理学的治疗。
