X盒結合蛋白1標的氧化壓力誘導生長抑制因子1藉由維持自噬作用以保護棕櫚酸誘發的血管脂毒性

Oxidative Stress-Induced Growth Inhibitor 1, a Target of X-Box-Binding Protein 1, Protects Palmitic Acid-Induced Vascular Lipotoxicity through Maintaining Autophagy

許崇善(Chong-Sun Khoi)

指導教授 ： 姜至剛

國立臺灣大學/醫學院/毒理學研究所/博士(2022年)

https://doi.org/10.6342/NTU202202226

摘要

飽和脂肪酸 (saturated fatty acids) 與代謝症候群密切相關，也是心血管疾病 (cardiovascular disease, CVD) 的危險因子，其誘導的血管脂毒性在內質網壓力 (ER stress)下的機制尚不清楚。因此，在此研究中，我們探討剪接型 X盒 結合蛋白 1 (XBP1s) 的標的基因:氧化壓力誘導生長抑制因子 1 (oxidative stress induced growth inhibitor 1, OSGIN1) 在棕櫚酸(palmitic acid, PA) 誘導的血管功能障礙中所扮演的角色。 首先，PA會抑制人臍靜脈內皮細胞 (HUVEC) 的血管形成。同時，PA 誘導了 XBP1s 在HUVECs 中的表現。通過基因減量技術抑制 XBP1s (silencing XBP1s)可以減弱 XBP1s 的表現，同時也延緩細胞遷移(cell migration)，並且減少內皮一氧化氮合成酶 (eNOS) 的表現。 在PA 的處理下，我們透過核醣核酸測序分析(RNA sequencing analysis)發現OSGIN1 可能是XBP1s 的標的基因。 接下來藉由基因減量技術抑制OSGIN1(silencing of OSGIN1)發現其可以透過降低磷酸化 eNOS (p-eNOS)來抑制細胞的遷移。 此外，PA 也會活化血管內皮細胞的自噬作用(autophagy); 我們透過使用 3-甲基腺嘌呤 (3-MA) 去証實3-MA可以抑制PA誘發的自噬作用並減少血管內皮細胞的遷移。另外，實驗結果發現，基因減量技術抑制 XBP1s 和 OSGIN1 會減少 LC3 II 的誘導；因此推論OSGIN1 可以維持自噬作用以保護血管內皮細胞的遷移作用。結論為，PA 會誘導血管內皮細胞的內質網壓力並活化 IRE1α-XBP1s途徑。 OSGIN1 是 XBP1s 的標的基因，其可通過調節自噬作用來保護內皮細胞以免受血管脂毒性的傷害。

關鍵字

棕櫚酸 ； 氧化壓力誘導生長抑制因子 1 ； 未摺疊蛋白反應 ； 剪接型 X-盒結合蛋白 1 ； 自噬作用 ； 內皮一氧化氮合成酶 ； 血管內皮細胞

並列摘要

Saturated fatty acids (SFAs) are closely associated with metabolic syndrome and risk factors for cardiovascular disease (CVD), and the mechanism by which they induce vascular lipotoxicity under endoplasmic reticulum stress (ER stress) is unclear. Therefore, in the present study, we investigated the role of target genes of splicing X-box-binding proteins 1 (XBP1s): oxidative stress-induced growth inhibitor 1 (OSGIN1) in the induction of palmitic acid (PA) in vascular dysfunction . First, PA inhibits angiogenesis in human umbilical vein endothelial cells (HUVEC). Meanwhile, PA induced the expression of XBP1s in HUVECs. By silencing XBP1s, the expression of XBP1s can be attenuated, and it can also delay cell migration and reduce the expression of endothelial nitric oxide synthase (eNOS). Under PA treatment, we identified OSGIN1 as a possible target gene of XBP1s through RNA-sequencing analysis. Next, by silencing OSGIN1, it was found to inhibit cell migration by reducing phosphorylated eNOS (p-eNOS). In addition, PA can also activate autophagy in vascular endothelial cells; we used 3-methyladenine (3-MA) to demonstrate that 3-MA inhibits PA-induced autophagy and reduces vascular endothelial cell migration. Furthermore, the experimental results found that silencing XBP1s and OSGIN1 reduced the induction of LC3 II; therefore, it was speculated that OSGIN1 could maintain autophagy to protect vascular endothelial cell migration. In conclusion, PA induces endoplasmic reticulum stress and activates the IRE1α-XBP1s pathway in vascular endothelial cells. OSGIN1, a target gene of XBP1s, protects endothelial cells from vascular lipotoxicity by regulating autophagy.

並列關鍵字

palmitic acid ； OSGIN1 ； unfolded protein response ； XBP1s ； autophagy ； eNOS ； endothelial cells

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