Department of Biological Sciences, Advanced Environmental Research Institute, University of North Texas, Denton, TX 76201, USA.
Center for Medical Genetics, Institute of Molecular Medicine, University of North Texas Health Sciences Center, Fort Worth, TX 76107, USA.
Environ Res. 2020 Feb;181:108913. doi: 10.1016/j.envres.2019.108913. Epub 2019 Nov 14.
Air pollution exposure is known to contribute to the progression of cardiovascular disease (CVD) and there is increasing evidence that dysbiosis of the gut microbiome may also play a role in the pathogenesis of CVD, including atherosclerosis. To date, the effects of inhaled air pollution mixtures on the intestinal epithelial barrier (IEB), and microbiota profiles are not well characterized, especially in susceptible individuals with comorbidity. Thus, we investigated the effects of inhaled ubiquitous air-pollutants, wood-smoke (WS) and mixed diesel and gasoline vehicle exhaust (MVE) on alterations in the expression of markers of integrity, inflammation, and microbiota profiles in the intestine of atherosclerotic Apolipoprotein E knockout (ApoE) mice. To do this, male 8 wk-old ApoE mice, on a high-fat diet, were exposed to either MVE (300 μg/m PM), WS; (∼450 μg/m PM), or filtered air (FA) for 6 h/d, 7 d/wk, for 50 d. Immunofluorescence and RT-PCR were used to quantify the expression of IEB components and inflammatory factors, including mucin (Muc)-2, tight junction (TJ) proteins, matrix metalloproteinase (MMP)-9, tumor necrosis factor (TNF)-α, and interleukin (IL)-1β, as well as Toll-like receptor (TLR)-4. Microbial profiling of the intestine was done using Illumina 16S sequencing of V4 16S rRNA PCR amplicons. We observed a decrease in intestinal Muc2 and TJ proteins in both MVE and WS exposures, compared to FA controls, associated with a significant increase in MMP-9, TLR-4, and inflammatory marker expression. Both WS and MVE-exposure resulted in decreased intestinal bacterial diversity, as well as alterations in microbiota profiles, including the Firmicutes: Bacteroidetes ratio at the phylum level. Our findings suggest inhalation exposure to either MVE or WS result in alterations in components involved in mucosal integrity, and also microbiota profiles and diversity, which are associated with increased markers of an inflammatory response.
空气污染暴露已知会导致心血管疾病 (CVD) 的进展，越来越多的证据表明肠道微生物组的失调也可能在 CVD 的发病机制中起作用，包括动脉粥样硬化。迄今为止，吸入空气污染物混合物对肠道上皮屏障 (IEB) 和微生物组谱的影响尚未得到很好的描述，尤其是在合并症的易感个体中。因此，我们研究了吸入普遍存在的空气污染物，包括木烟 (WS) 和混合柴油和汽油车辆尾气 (MVE) 对动脉粥样硬化载脂蛋白 E 敲除 (ApoE) 小鼠肠道完整性、炎症标志物表达和微生物组谱的改变。为此，雄性 8 周龄 ApoE 小鼠高脂饮食，每天暴露于 MVE (300μg/m3 PM)、WS(∼450μg/m3 PM)或过滤空气 (FA) 中 6 小时/天，每周 7 天，共 50 天。免疫荧光和 RT-PCR 用于定量 IEB 成分和炎症因子的表达，包括粘蛋白 (Muc)-2、紧密连接 (TJ) 蛋白、基质金属蛋白酶 (MMP)-9、肿瘤坏死因子 (TNF)-α 和白细胞介素 (IL)-1β，以及 Toll 样受体 (TLR)-4。肠道微生物组谱采用 Illumina 16S 测序 V4 16S rRNA PCR 扩增子进行分析。与 FA 对照组相比，我们观察到 MVE 和 WS 暴露后肠道 Muc2 和 TJ 蛋白减少，同时 MMP-9、TLR-4 和炎症标志物表达显著增加。WS 和 MVE 暴露都导致肠道细菌多样性减少，微生物组谱发生改变，包括厚壁菌门:拟杆菌门比例在门水平上。我们的研究结果表明，吸入 MVE 或 WS 暴露会改变参与粘膜完整性的成分，以及微生物组谱和多样性，这与炎症反应标志物的增加有关。
