Department of Animal Sciences, Centre de Recherche en Reproduction, Développement et Santé Intergénérationnelle (CRDSI), Laval University, Quebec City G1V 0A6, Canada.
Norwegian Polar Institute, Fram Centre, NO-9296 Tromsø, Norway.
Environ Sci Technol. 2020 Sep 15;54(18):11365-11375. doi: 10.1021/acs.est.0c01920. Epub 2020 Aug 30.
Being at the food chain apex, polar bears () are highly contaminated with persistent organic pollutants (POPs). Females transfer POPs to their offspring through gestation and lactation; therefore, young cubs present higher POPs concentrations than their mothers. Recent studies suggest that POPs affect the lipid metabolism in female polar bears; however, the mechanisms and impact on their offspring remain unknown. Here, we hypothesized that exposure to POPs differentially alters genome-wide gene transcription in the adipose tissue from mother polar bears and their cubs, highlighting molecular differences in response between adults and young. Adipose tissue biopsies were collected from 13 adult female polar bears and their twin cubs in Svalbard, Norway, in April 2011, 2012, and 2013. Total RNA extracted from biopsies was subjected to next-generation RNA sequencing. Plasma concentrations of summed polychlorinated biphenyls, organochlorine pesticides, and polybrominated diphenyl ethers in mothers ranged from 897 to 13620 ng/g wet weight and were associated with altered adipose tissue gene expression in both mothers and cubs. In mothers, 2502 and 2586 genes in total were positively and negatively, respectively, correlated to POP exposure, whereas in cubs, 2585 positively and 1690 negatively genes. Between mothers and cubs, 743 positively and negatively genes overlapped between mothers and cubs suggesting partially shared molecular responses to ΣPOPs. ΣPOP-associated genes were involved in numerous metabolic pathways in mothers and cubs, indicating that POP exposure alters the energy metabolism, which, in turn, may be linked to metabolic dysfunction.
处于食物链顶端的北极熊（Polar bears）体内高度积聚了持久性有机污染物（POPs）。雌性北极熊通过妊娠和哺乳将 POPs 传递给后代；因此，幼崽体内的 POPs 浓度高于其母亲。最近的研究表明，POPs 会影响雌性北极熊的脂代谢；然而，其对后代的影响机制尚不清楚。在这里，我们假设暴露于 POPs 会使母熊及其幼崽的脂肪组织中的全基因组基因转录发生差异变化，突出了成年动物和幼崽之间在反应上的分子差异。2011 年、2012 年和 2013 年 4 月，在挪威斯瓦尔巴群岛（Svalbard）采集了 13 只成年雌性北极熊及其双胞胎幼崽的脂肪组织活检。从活检中提取的总 RNA 进行了下一代 RNA 测序。母亲体内的总多氯联苯（PCBs）、有机氯农药（organochlorine pesticides）和多溴二苯醚（polybrominated diphenyl ethers）的浓度范围为 897 至 13620ng/g 湿重，与母亲和幼崽脂肪组织基因表达的改变有关。在母亲体内，受 POP 暴露影响的总共有 2502 个和 2586 个基因分别呈正相关和负相关，而在幼崽体内，分别有 2585 个和 1690 个基因呈正相关和负相关。在母亲和幼崽之间，有 743 个基因呈正相关和负相关，表明二者之间存在部分共享的分子反应，表明二者之间存在部分共享的分子反应。与 ΣPOP 相关的基因在母亲和幼崽体内参与了许多代谢途径，表明 POP 暴露改变了能量代谢，而这反过来又可能与代谢功能障碍有关。
