ApoE 基因缺乏母鼠施打 DNA 甲基轉移酶抑制劑對子代小鼠動脈粥狀硬化進程之影響：巨噬細胞極化分化之角色

Abstract

動脈粥狀硬化在國內外都具有極高的盛行率及致死率。除受到飲食影響，目前也已知基因組的高甲基化與心血管疾病成正相關。根據研究顯示母親高膽固醇血脂症會藉著 DNA 甲基化的方式影響胎兒在子宮內的發育，且讓子代成年後有較高的機會罹患代謝相關疾病或心血管疾病，但目前對於親代如何透過表觀遺傳學的方式調控子代動脈粥狀硬化的機制尚不清楚。因此本實驗以控制組飲食（control diet, CD）誘導親代母鼠，並於孕前及哺乳期以腹腔注射方式給予 DNA 甲基轉移酶抑製劑 5-aza-2’-deoxycytidine 探討是否可以減輕子代罹患動脈粥狀硬化的風險。 本實驗以 ApoE-/- 小鼠為模式，妊娠前以控制組飲食（control diet, CD）誘導親代母鼠，並隨機分配施打 PBS 或5Aza-dC，其生下的子代統一餵食 WD（western diet, WD），故本實驗子代小鼠可分成兩組：PBS+ CW組及5Aza-dC + CW組。 我們發現和 PBS+ CW 組相比，5Aza-dC + CW 組受到親代 5Aza-dC 處理的影響，減緩成年後罹患動脈粥狀硬化的風險，且在血液及脾臟中發現有較低比例的 CD8 T 細胞。此外，我們也發現親代母鼠施打 5Aza-dC 會減緩子代雄鼠 M1 巨噬細胞的極化分化，抑制促發炎反應，因而減緩動脈粥狀硬化斑塊的形成。進一步探討其機制發現與 PBS + CW 組相比，於 5Aza-dC + CW 組子代雄鼠中 5Aza-dC 處理有抗發炎作用且使調控巨噬細胞極化分化的 Hmox1 基因表現量顯著上升，其上游轉錄因子 Nfe2l2 表現量也有相同的趨勢。 總結，我們發現親代母鼠 5Aza-dC 處理，會透過抑制子代 M1 巨噬細胞的極化分化及發炎反應來減緩子代罹患動脈粥狀硬化病症的風險。

It is increasingly recognized that in utero environment is an important determinant of adult disease. Maternal hypercholesterolemia increases the susceptibility of atherosclerosis in offspring through epigenetic, yet the mechanisms are poorly understood. We aim to study whether inhibition of DNA methylation in Apolipoprotein E knockout (ApoE-/-) dams ameliorates atherosclerosis in adult offspring. In our study, ApoE-/- female mice were fed with a control diet (CD). Meanwhile, PBS or DNA methyltransferase inhibitor 5-aza-2'-deoxycytidine (5Aza-dC) was adminisered before pregnancy and during lactation. All offspring were fed with a western diet (WD) starting from weaning to 16 weeks of age. Two groups of offspring were generated: PBS + CW, 5Aza-dC + CW. Compare to PBS + CW group, 5Aza-dC + CW group developed markedly decreased atherosclerotic lesions and exhibited lower proportions of CD8 T cells in peripheral blood mononuclear cells (PBMCs) and splenocytes. In addition, maternal 5Aza-dC treatment decreased the expression of M1 macrophage markers CD86 and proinflammatory cytokine production in male offspring. To explore the molecular mechanism, we observed the upregulation of transcription factor Nfe2l2 (Nrf2) and its target gene Hmox1 (HO-1) in 5Aza-dC + CW group compare to PBS + CW group. Taken together, we demonstrated that maternal 5Aza-dC treatment ameliorated the progression of atherosclerosis likely through inhibition of inflammatory response and avtivation of Nrf2/HO-1 pathway in macrophage.