Department of Human Health and Nutritional Sciences, University of Guelph , Guelph, ON , Canada.
Department of Human Health and Nutritional Sciences, University of Guelph , Guelph, ON , Canada ; Guelph Food Research Centre, Agriculture and Agri-Food Canada , Guelph, ON , Canada.
Front Nutr. 2015 Oct 13;2:31. doi: 10.3389/fnut.2015.00031. eCollection 2015.
Adipose tissue (AT) macrophages (ATM) play a key role in obesity-associated pathologies, and their phenotype can be influenced by the local tissue microenvironment. Interestingly, long-chain n-3 polyunsaturated fatty acids (LC n-3 PUFA) and the LC n-3 PUFA-upregulated adipokine, adiponectin (Ad), may mitigate excessive ATM inflammatory M1-polarization responses. However, to what extent LC n-3 PUFA and Ad work in concert to affect macrophage phenotype has not been examined. Thus, we used an established ex vivo AT organ culture model using visceral AT from mice fed a control (CON; 10% w/w safflower oil) n-6 PUFA-rich diet or an isocaloric fish oil (FO; 3% w/w menhaden oil + 7% w/w safflower oil)-derived LC n-3 PUFA-rich diet to generate AT conditioned media (ACM). We then evaluated if CON or FO ACM affected macrophage polarization markers in a model designed to mimic acute [18 h ACM plus lipopolysaccharide (LPS) for the last 6 h] or chronic (macrophages treated with LPS-challenged CON or FO ACM for 24 h) inflammation ± Ad-neutralizing antibody and the LPS-neutralizing agent, polymyxin B. In the acute inflammation model, macrophages treated with FO ACM had decreased lipid uptake and mRNA expression of M1 markers (Nos2, Nfκb, Il6, Il18, Ccl2, and Ccl5) compared with CON ACM (p ≤ 0.05); however, these effects were largely attenuated when Ad was neutralized (p > 0.05). Furthermore, in the chronic inflammation model, macrophages treated with FO ACM had decreased mRNA expression of M1 markers (Nos2, Tnfα, Ccl2, and Il1β) and IL-6 and CCL2 secretion (p ≤ 0.05); however, some of these effects were lost when Ad was neutralized, and were further exacerbated when both Ad and LPS were neutralized. Taken together, this work shows that LC n-3 PUFA and Ad work in concert to suppress certain M1 macrophage responses. Thus, future strategies to modulate the ATM phenotype should consider the role of both LC n-3 PUFA and Ad in mitigating obese AT inflammation.
脂肪组织（AT）巨噬细胞（ATM）在肥胖相关病理中发挥关键作用，其表型可受局部组织微环境影响。有趣的是，长链 n-3 多不饱和脂肪酸（LC n-3 PUFA）和 LC n-3 PUFA 上调的脂肪因子脂联素（Ad）可能减轻过度的 ATM 炎症 M1 极化反应。然而，LC n-3 PUFA 和 Ad 协同作用影响巨噬细胞表型的程度尚未得到检验。因此，我们使用已建立的离体 AT 器官培养模型，使用喂食对照（CON；10%w/w红花油）n-6 PUFA 丰富饮食或等热量鱼油（FO；3%w/w鲱鱼油+7%w/w红花油）衍生 LC n-3 PUFA 丰富饮食的小鼠内脏 AT 生成 AT 条件培养基（ACM）。然后，我们评估 CON 或 FO ACM 是否影响模拟急性[18 小时 ACM 加最后 6 小时脂多糖（LPS）]或慢性（用 LPS 挑战的 CON 或 FO ACM 处理 24 小时的巨噬细胞）炎症的巨噬细胞极化标志物±Ad 中和抗体和 LPS 中和剂多粘菌素 B。在急性炎症模型中，与 CON ACM 相比，用 FO ACM 处理的巨噬细胞摄取脂质减少，M1 标志物（Nos2、Nfκb、Il6、Il18、Ccl2 和 Ccl5）的 mRNA 表达降低（p≤0.05）；然而，当 Ad 被中和时，这些作用在很大程度上被减弱（p>0.05）。此外，在慢性炎症模型中，用 FO ACM 处理的巨噬细胞 M1 标志物（Nos2、Tnfα、Ccl2 和 Il1β）的 mRNA 表达以及 IL-6 和 CCL2 的分泌减少（p≤0.05）；然而，当 Ad 被中和时，其中一些作用丢失，当 Ad 和 LPS 都被中和时，作用进一步加剧。总之，这项工作表明 LC n-3 PUFA 和 Ad 协同作用抑制某些 M1 巨噬细胞反应。因此，未来调节 ATM 表型的策略应考虑 LC n-3 PUFA 和 Ad 在减轻肥胖 AT 炎症中的作用。
