Identifying tobacco-genetic interactions through study of the aryl hydrocarbon receptor pathway.

通过研究芳基碳氢化合物受体途径来识别烟草与遗传的相互作用。

• 批准号: 10207112
• 负责人: THOMAS QUERTERMOUS
• 金额: $ 66.85万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-04-01 至 2025-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10207112
• 关键词: ARNT gene; Address; Affect; Alkaline Phosphatase; Anatomy; Animal Model; Apolipoprotein E; Arterial Fatty Streak; Aryl Hydrocarbon Receptor; Atherosclerosis; Binding; Biological Assay; Biological Models; Cardiovascular Diseases; Cardiovascular system; Cell Lineage; Cell model; Cells; Cessation of life; Chondrocytes; Coronary Arteriosclerosis; Coronary artery; Data; Dioxins; Disease; Disease Progression; Disease model; Environmental Exposure; Environmental Risk Factor; Epigenetic Process; Exposure to; Functional disorder; Genes; Genetic; Genetic Transcription; Goals; Heterodimerization; Histology; Human; Human Genetics; Human Genome; In Vitro; Individual; Knock-out; Knockout Mice; Lesion; Ligands; Link; Mediating; Modeling; Molecular; Morbidity - disease rate; Mus; Pathway interactions; Phenotype; Physiological; Population; Receptor Signaling; Research; Risk; Role; Smooth Muscle Myocytes; Tissues; Tobacco; Tobacco smoke; Toxic Environmental Substances; Toxin; United States; Vascular Diseases; Vascular calcification; Wild Type Mouse; XCL1 gene; Xenobiotics; aryl hydrocarbon receptor ligand; aryl hydrocarbons; conditional knockout; disorder risk; epigenomics; exposed human population; gene environment interaction; genetic approach; genetic association; in vitro Model; in vivo; innovation; insight; loss of function; mortality; mouse model; novel; novel strategies; preventable death; promoter; protective effect; public health relevance; response; reverse genetics; single-cell RNA sequencing; transcription factor; transcriptomics

Human exposure to environmental toxins such as those in tobacco related products are the leading cause of preventable deaths in the United States, with the greatest effect on morbidity and mortality through promotion of coronary artery disease (CAD). However, the molecular mechanisms by which environmental exposures increase CAD risk are not well understood. Furthermore, genes that might participate in gene by environment interactions have been difficult to identify at the population level. Thus, our longterm goal is to use a reverse genetics approach to study the interaction of xenobiotic toxins with relevant known CAD-associated genes. One such gene is the aryl-hydrocarbon receptor (AHR). Well-known ligands of AHR are dioxins and poly-aryl hydrocarbons, which are major components of tobacco smoke and known promoters of atherosclerosis in animal models. Genes encoding AHR, its heterodimerization partner ARNT, and other factors in this pathway are all linked to CAD risk through human genetic association studies. Single cell RNA sequencing (scRNAseq) studies of smooth muscle cell (SMC)-specific Ahr knockout (KO) atherosclerotic mice showed a significant increase in the proportion of phenotypic transition SMC that express chondrocyte markers, identifying cells we term “chondromyocytes” (CMC). These findings were correlated with larger lesion size, increased lineage- traced SMC contribution to the plaque, decreased lineage-traced SMC in the fibrous cap, and increased lesion alkaline phosphatase activity in the Ahr KO mice. These findings reveal that Ahr expression in SMC inhibits their transition to CMC and ameliorates vascular disease pathophysiology. These data are in contrast with a number of studies showing that Ahr activation by xenobiotic ligands such as dioxin promote atherosclerosis, and suggest a unique hypothesis. We postulate that Ahr normally has a beneficial effect on SMC in the disease setting, inhibiting a harmful cell state transition to the CMC phenotype and disease progression, and that this protective effect is blocked by xenobiotic toxin activation. We thus propose to examine this hypothesis through the following Aims. In Aim 1, we will investigate how Ahr responds to xenobiotic ligand activation in the disease setting, with respect to SMC phenotype and cellular lesion anatomy. These studies will employ the Ahr SMC-specific conditional KO and SMC lineage traced ApoE KO atherosclerosis model. Aim 2 will focus on the transcriptomic and epigenomic effects of xenobiotic ligand in vivo activation with the same mouse disease model, with combined scRNAseq and single cell ATAC sequencing (scATACseq). Finally, in Aim 3 we propose to employ human coronary artery SMC as an in vitro model system to validate, and characterize the downstream pathways for, TFs identified in the previous Aim that interact with AHR to regulate the phenotypic transition of SMC to chondromyocytes. These studies investigate a highly innovative hypothesis, and will provide significant insights into cellular and molecular mechanisms by which tobacco and other environmental risk factors promote CAD risk.

人类接触环境毒素（例如烟草相关产品中的毒素）是导致疾病的主要原因 美国可预防的死亡，通过推广对发病率和死亡率影响最大 冠状动脉疾病（CAD）。然而，环境暴露的分子机制 CAD 风险的增加尚不十分清楚。此外，可能通过环境参与基因的基因 在人口层面上很难确定相互作用。因此，我们的长期目标是使用反向 遗传学方法研究外源毒素与相关已知 CAD 相关基因的相互作用。 其中一种基因是芳基烃受体（AHR）。 AHR 的著名配体是二恶英和聚芳基 碳氢化合物，是烟草烟雾的主要成分，也是已知的动脉粥样硬化促进剂 动物模型。编码 AHR 的基因、其异二聚化伙伴 ARNT 以及该途径中的其他因子 通过人类遗传关联研究，所有这些都与 CAD 风险相关。单细胞 RNA 测序 (scRNAseq) 对平滑肌细胞 (SMC) 特异性 Ahr 敲除 (KO) 动脉粥样硬化小鼠的研究显示， 表达软骨细胞标记物的表型转变 SMC 的比例增加，从而识别我们的细胞 术语“软骨肌细胞”（CMC）。这些发现与较大的病变大小、谱系增加相关。 追踪 SMC 对斑块的贡献，纤维帽中谱系追踪的 SMC 减少，病变增加 Ahr KO 小鼠的碱性磷酸酶活性。这些发现表明 SMC 中的 Ahr 表达抑制 它们向 CMC 的转变并改善血管疾病的病理生理学。这些数据与 大量研究表明，二恶英等异生配体激活 Ahr 会促进动脉粥样硬化， 并提出一个独特的假设。我们假设 Ahr 通常对 SMC 具有有益的影响 疾病环境，抑制有害细胞状态向 CMC 表型和疾病的转变 进展，并且这种保护作用被外源毒素激活所阻断。因此我们建议 通过以下目标检验这一假设。在目标 1 中，我们将调查 Ahr 如何应对 疾病环境中的异生配体激活，涉及 SMC 表型和细胞病变解剖学。 这些研究将采用 Ahr SMC 特异性条件 KO 和 SMC 谱系追踪的 ApoE KO 动脉粥样硬化模型。目标 2 将重点关注外源配体的转录组和表观基因组效应 使用相同的小鼠疾病模型进行体内激活，结合 scRNAseq 和单细胞 ATAC 测序（scATACseq）。最后，在目标 3 中，我们建议采用人冠状动脉 SMC 作为体外 模型系统，用于验证和表征先前目标中确定的 TF 的下游路径 与 AHR 相互作用，调节 SMC 向软骨肌细胞的表型转变。这些研究 研究高度创新的假设，并将提供对细胞和分子的重要见解 烟草和其他环境风险因素促进 CAD 风险的机制。