Commercial uranium mining on the Navajo Nation has subjected communities on tribal lands in the Southwestern United States to exposures from residual environmental contamination. Vascular health effects from these ongoing exposures are an active area of study. There is an association between residential mine-site proximity and circulating biomarkers in residents, however, the contribution of mine-site derived wind-blown dusts on vascular and other health outcomes is unknown. To assess neurovascular effects of mine-site derived dusts, we exposed mice using a novel exposure paradigm, the AirCARE1 mobile inhalation laboratory, located 2 km from an abandoned uranium mine, Claim 28 in Blue Gap Tachee, AZ. Mice were exposed to filtered air (FA) (n = 6) or concentrated ambient particulate matter (CAPs) (n = 5) for 2 wks for 4 h per day. To assess miRNA differential expression in cultured mouse cerebrovascular cells following particulate matter (PM) exposure (average: 96.6 ± 60.4 μg/m3 for all 4 h exposures), the serum cumulative inflammatory potential (SCIP) assay was employed. MiRNA sequencing was then performed in cultured mouse cerebrovascular endothelial cells (mCECs) to evaluate transcriptional changes. Results indicated 27 highly differentially expressed (p < 0.01) murine miRNAs, as measured in the SCIP assay. Gene ontology (GO) pathway analysis revealed notable alterations in GO enrichment related to the cytoplasm, protein binding and the cytosol, while significant KEGG pathways involved pathways in cancer, axon guidance and Wnt signaling. Expression of these 27 identified, differentially expressed murine miRNAs were then evaluated in the serum. Nine of these miRNAs (~ 30%) were significantly altered in the serum and 8 of those miRNAs demonstrated the same directional change (either upregulation or downregulation) as cellular miRNAs, as measured in the SCIP assay. Significantly upregulated miRNAs in the CAPs exposure group included miRNAs in the let-7a family. Overexpression of mmu-let-7a via transfection experiments, suggested that this miRNA may mediate mCEC barrier integrity following dust exposure. Our data suggest that mCEC miRNAs as measured in the SCIP assay show similarity to serum-borne miRNAs, as approximately 30% of highly differentially expressed cellular miRNAs in the SCIP assay were also found in the serum. While translocation of miRNAs via exosomes or an alternative mechanism is certainly possible, other yet-to-be-identified factors in the serum may be responsible for significant miRNA differential expression in endothelium following inhaled exposures. Additionally, the most highly upregulated murine miRNAs in the CAPs exposure group were in the let-7a family. These miRNAs play a prominent role in cell growth and differentiation and based on our transfection experiments, mmu-let-7a may contribute to cerebrovascular mCEC alterations following inhaled dust exposure.

中文翻译：

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在纳瓦霍国家一个废弃的铀矿附近，颗粒物暴露后，血清中的因素改变了脑血管内皮微RNA的表达。

纳瓦霍族国家的商业铀矿开采使美国西南部部落土地上的社区遭受了残留环境污染的威胁。这些持续暴露对血管健康的影响是研究的一个活跃领域。居民矿井附近与居民中的循环生物标志物之间存在关联，但是，矿井产生的风吹尘对血管和其他健康结果的贡献尚不清楚。为了评估矿场产生的粉尘对神经血管的影响，我们使用一种新型的暴露范式AirCARE1移动吸入实验室对小鼠进行了暴露，该实验室距废弃的铀矿2公里，位于亚利桑那州Blue Gap Tachee，距废弃的铀矿2公里。每天将小鼠暴露于过滤空气（FA）（n = 6）或浓缩的环境颗粒物（CAPs）（n = 5）中，每天2周，持续4 h。为了评估微粒物质（PM）暴露（所有4 h暴露平均值：96.6±60.4μg/ m3）后培养的小鼠脑血管细胞中miRNA的差异表达，采用了血清累积炎症潜能（SCIP）测定。然后在培养的小鼠脑血管内皮细胞（mCEC）中进行MiRNA测序，以评估转录变化。结果表明，如在SCIP分析中所测量的，27种高度差异表达（p <0.01）的鼠miRNA。基因本体论（GO）途径分析显示，GO富集与细胞质，蛋白质结合和细胞质有关，且显着改变，而重要的KEGG途径涉及癌症，轴突引导和Wnt信号传导途径。然后在血清中评估这27种已鉴定的差异表达的鼠miRNA的表达。如在SCIP分析中所测，这些miRNA中的九个（〜30％）在血清中发生了显着变化，并且这些miRNA中的8个显示出与细胞miRNA相同的方向变化（上调或下调）。CAPs暴露组中显着上调的miRNA包括let-7a家族中的miRNA。通过转染实验，mmu-let-7a的过度表达表明该miRNA可能在粉尘暴露后介导mCEC屏障的完整性。我们的数据表明，在SCIP分析中测得的mCEC miRNA与血清源miRNA相似，因为在血清中也发现了约30％的SCIP分析中高度差异表达的细胞miRNA。虽然通过外泌体或其他机制转运miRNA当然是可能的，血清中的其他尚未确定的因素可能是吸入暴露后内皮中显着的miRNA差异表达的原因。此外，CAPs暴露组中表达最高的鼠类miRNA属于let-7a家族。这些miRNA在细胞生长和分化中起着重要作用，根据我们的转染实验，mmu-let-7a可能与吸入粉尘后的脑血管mCEC改变有关。