N,N-dimethylsphingosine attenuates myocardial ischemia-reperfusion injury by recruiting regulatory T cells through PI3K/Akt pathway in mice
N,N-dimethylsphingosine attenuates myocardial ischemia-reperfusion injury by recruiting regulatory T cells through PI3K/Akt pathway in mice
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DOI：
10.1007/s00395-016-0548-3
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发表时间：
2016-03-01
影响因子：
9.5
通讯作者：
Chen, Lianglong
中科院分区：
文献类型：
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作者：
Fang, Jun;Hu, Fudong;Chen, Lianglong
N，N-二甲基鞘氨醇(DMS)在体外对心肌缺血再灌注损伤(IRI)具有保护作用，并能募集CD4(+)CD25(+)Foxp3(+)调节性T细胞(Tregs)，可能参与心脏保护作用。我们推测，当在心肌缺血后在体内应用DMS时，DMS可能通过招募Tregs而具有心脏保护作用。C57BL/6小鼠结扎左冠状动脉主干后松弛，造成心肌缺血再灌注损伤模型，缺血5min后静脉注射二甲双吗啉(0.43 mg/kg)。结果发现，与缺血再灌注组相比，野生型(WT)小鼠心肌梗死面积(47.1±/-8.9vs.33.1+/-3.4%，p<；0.01)和再灌流24 h时中性粒细胞浸润(P<；0.01)明显减少，Tregs聚集率[(6+/-1)/mm(2)vs.(30+/-4)/mm(2)，p<；免疫荧光染色显示再灌流1h达高峰，实时定量聚合酶链式反应(Real-time PCR)显示再灌流4hR时炎性因子基因表达降低。这种保护可被磷脂酰肌醇3-激酶(PI3K)/Akt抑制剂或Tregs耗竭抗体所消除。与WT小鼠相比，T细胞和B细胞缺陷的Rag2基因敲除(KO)小鼠的心脏保护作用不被DMS或DMS和过继转移的Tregs所增强，但可被DMS和WT非Tregs所消除，并可通过与WT Tregs共转移而不被Akt1(+/-)小鼠来源的Tregs重新获得。综上所述，在缺血早期应用DMS，可能通过PI3K/Akt途径募集Tregs，对心肌IRI具有体内保护作用。
N,N-dimethylsphingosine (DMS) has been documented to be in vitro protective against myocardial ischemia-reperfusion injury (IRI) and can recruit CD4(+)CD25(+)Foxp3(+) regulatory T cells (Tregs), which may participate in the cardioprotection. We hypothesized that when in vivo applied after a myocardial ischemia, DMS may be cardioprotective by recruiting Tregs. Myocardial IRI was induced in C57BL/6 mice by occluding the left main coronary arteries followed by relaxation, and DMS (0.43 mg/kg) was intravenously injected 5 min after the onset of ischemia. We found that in wild-type (WT) mice, compared with the ischemia-reperfusion group, DMS reduced the infarct size (47.1 +/- 8.9 vs. 33.1 +/- 3.4 %, p < 0.01), and neutrophil infiltration at 24 h reperfusion (R) evaluated by TTC and immunohistochemical staining, respectively, and increased the aggregation of Tregs [(6 +/- 1)/mm(2) vs. (30 +/- 4)/mm(2), p < 0.01], peaking at 1 h R by immunofluorescence staining, with reduced gene expression of inflammatory factors at 4 h R in the reperfused myocardium by real-time PCR. This protection was abolished by phosphatidylinositol 3-kinase (PI3K)/Akt inhibitor or Tregs-depleting antibody. Relative to WT mice, the cardioprotection conferred by T cell-and B cell-deficient Rag2 knockout (KO) mice was not strengthened by DMS or by DMS and the adoptive transfer of Tregs from WT mice, but was abolished by DMS and WT non-Tregs and was recaptured by the cotransfer with WT Tregs but not with Akt1(+/-) mice-derived Tregs. In conclusion, applied at an early stage of ischemia, DMS may be in vivo protective against myocardial IRI by recruiting Tregs via PI3K/Akt pathway.