Inhibition of cytokine signaling in human retinal endothelial cells through modification of caveolae/lipid rafts by docosahexaenoic acid
Inhibition of cytokine signaling in human retinal endothelial cells through modification of caveolae/lipid rafts by docosahexaenoic acid
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DOI：
10.1167/iovs.06-0619
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发表时间：
2007-01-01
影响因子：
4.4
通讯作者：
Busik, Julia V.
中科院分区：
文献类型：
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作者：
Chen, Weiqin;Jump, Donald B.;Busik, Julia V.
目的。二十二碳六烯酸 (DHA(22:6,n3)) 是视网膜中主要的 n3 多不饱和脂肪酸 (PUFA)。作者之前证明，DHA(22: 6,n3) 可抑制原代人视网膜血管内皮 (hRVE) 细胞（受糖尿病视网膜病变影响的靶组织）中细胞因子诱导的粘附分子表达。尽管血管炎症在糖尿病视网膜病变中很重要，但 DHA(22:6,n3) 在血管内皮细胞中抗炎作用的机制尚不清楚。在这项研究中，作者提出了这样的假设：DHA(22:6,n3) 通过改变细胞膜窝/脂筏的脂质组成来发挥作用，从而改变这些特殊质膜微域中重要信号传导事件的结果。方法。 hRVE细胞在存在或不存在DHA(22:6,n3)的情况下培养。使用蔗糖梯度超速离心制备分离的小凹/富含脂筏的耐去污剂膜域。通过HPLC测量治疗前后小凹/脂筏的脂肪酸组成和胆固醇含量。通过Western blotting和免疫组化检测Src家族激酶的表达。结果。用胆固醇消耗剂甲基环糊精 (MCD) 破坏小窝/脂筏结构，可减少 hRVE 细胞中细胞因子诱导的信号传导。 hRVE 细胞在富含 DHA(22:6,n3) 的培养基中生长，导致 DHA(22:6,n3) 显着掺入细胞膜穴/脂筏的主要磷脂中，导致膜微区不饱和指数增加。小凹/脂筏中 DHA(22:6,n3) 的富集伴随着小凹/脂筏中胆固醇的 70% 消耗以及小凹/脂筏中 SFK、Fyn 和 c-Yes 的置换。向 DHA(22:6,n3) 处理的细胞中添加水溶性胆固醇可补充小窝/脂筏中的胆固醇，并逆转 DHA(22:6,n3) 对细胞因子诱导信号传导的影响。结论。将 DHA(22:6,n3) 掺入小窝/脂筏中磷脂的脂肪酰基链中，然后消耗胆固醇并置换重要信号分子，为 DHA(22:6,n3) 在 hRVE 细胞中的抗炎作用提供了潜在机制。
PURPOSE. Docosahexaenoic acid (DHA(22:6,n3)) is the principal n3 polyunsaturated fatty acid (PUFA) in the retina. The authors previously demonstrated that DHA(22: 6,n3) inhibited cytokine-induced adhesion molecule expression in primary human retinal vascular endothelial (hRVE) cells, the target tissue affected by diabetic retinopathy. Despite the importance of vascular inflammation in diabetic retinopathy, the mechanisms underlying anti-inflammatory effects of DHA(22:6,n3) in vascular endothelial cells are not understood. In this study the authors address the hypothesis that DHA(22:6,n3) acts through modifying lipid composition of caveolae/lipid rafts, thereby changing the outcome of important signaling events in these specialized plasma membrane microdomains.METHODS. hRVE cells were cultured in the presence or absence of DHA(22:6,n3). Isolated caveolae/lipid raft-enriched detergent-resistant membrane domains were prepared using sucrose gradient ultracentrifugation. Fatty acid composition and cholesterol content of caveolae/lipid rafts before and after treatment were measured by HPLC. The expression of Src family kinases was assayed by Western blotting and immunohistochemistry.RESULTS. Disruption of the caveolae/lipid raft structure with a cholesterol-depleting agent, methyl-cyclodextrin (MCD), diminished cytokine-induced signaling in hRVE cells. Growth of hRVE cells in media enriched in DHA(22:6,n3) resulted in significant incorporation of DHA(22:6,n3) into the major phospholipids of caveolae/lipid rafts, causing an increase in the unsaturation index in the membrane microdomain. DHA(22:6,n3) enrichment in the caveolae/raft was accompanied by a 70% depletion of cholesterol from caveolae/lipid rafts and displacement of the SFK, Fyn, and c-Yes from caveolae/lipid rafts. Adding water-soluble cholesterol to DHA(22:6,n3)-treated cells replenished cholesterol in caveolae/lipid rafts and reversed the effect of DHA(22:6,n3) on cytokine-induced signaling.CONCLUSIONS. Incorporation of DHA(22:6,n3) into fatty acyl chains of phospholipids in caveolae/lipid rafts, followed by cholesterol depletion and displacement of important signaling molecules, provides a potential mechanism for anti-inflammatory effect of DHA(22:6,n3) in hRVE cells.