Supplemental material for Mapping cord-blood transcriptome of early pregnancy maternal anemia to identify signatures of fetal programming

Abstract <b>Objective:</b> Anemia during early pregnancy (EP) is common in developing countries and is associated with adverse health consequences for both mother and children. Offspring of women with EP anemia often have low birth-weight, the latter being a risk factor for cardiometabolic diseases including type 2 diabetes (T2D) later in life. Mechanisms underlying developmental programming of adult cardiometabolic disease include epigenetic and transcriptional alterations potentially detectable in umbilical cord blood (UCB) at time of birth.<b>Methods:</b> We leveraged global transcriptome- and accompanying epigenome-wide changes in 48 UCB from newborns of EP-anemic Tanzanian mothers and 50 controls to identify differentially expressed genes (DEG) in UCB exposed to maternal EP-anemia. DEGs were assessed for association with neonatal anthropometry and cord insulin levels. These genes were further studied in expression data from human fetal pancreas and adult islets to understand their role in beta-cell development and/or function.<b>Results:</b> The expression of 137 genes was altered in UCB of newborns exposed to maternal EP anemia. These putative signatures of fetal programming which included the birth-weight locus <i>LCORL</i>, were potentially mediated by epigenetic changes in 27 genes and associated with neonatal anthropometry. Among the DEGs were <i>P2RX7, PIK3C2B,</i> and <i>NUMBL</i> which potentially influence beta-cell development. Insulin levels were lower in EP anemia exposed UCB, supporting the notion of developmental programming of pancreatic beta-cell dysfunction and subsequently increased risk of T2D in offspring of EP anemic mothers.<b>Conclusions:</b> Our data provide proof-of-concept on distinct transcriptional and epigenetic changes detectable in UCB from newborns exposed to maternal EP anemia.

<b>研究目的：</b> 早孕（early pregnancy, EP）贫血在发展中国家较为常见，可对孕产妇及子代健康造成不良影响。早孕贫血孕妇所产子代常出现低出生体重，而低出生体重是成年后罹患包括2型糖尿病（type 2 diabetes, T2D）在内的心血管代谢疾病的危险因素。成人心血管代谢疾病的发育编程机制，可能涉及出生时可在脐带血（umbilical cord blood, UCB）中检测到的表观遗传与转录组改变。
<b>研究方法：</b> 本研究纳入48份来自早孕贫血坦桑尼亚孕妇所产新生儿的脐带血样本及50份对照样本，通过分析其全局转录组及伴随的表观基因组变化，鉴定母体早孕贫血暴露后脐带血中的差异表达基因（differentially expressed genes, DEG）。随后评估差异表达基因与新生儿人体测量学指标及脐带血胰岛素水平的关联，并利用人类胎儿胰腺及成人胰岛的表达数据，进一步探究这些基因在β细胞发育及/或功能中的作用。
<b>研究结果：</b> 本研究发现，暴露于母体早孕贫血的新生儿脐带血中，共有137个基因的表达发生改变。这些胎儿发育编程的特征性标志（包括出生体重位点<i>LCORL</i>），可能由27个基因的表观遗传改变介导，并与新生儿人体测量学指标相关。差异表达基因中包含<i>P2RX7</i>、<i>PIK3C2B</i>及<i>NUMBL</i>，这些基因可能对β细胞发育产生影响。暴露于早孕贫血的脐带血中胰岛素水平更低，这支持了“胰腺β细胞功能障碍的发育编程会增加早孕贫血孕妇子代罹患2型糖尿病（T2D）风险”这一假说。
<b>研究结论：</b> 本研究结果为“暴露于母体早孕贫血的新生儿脐带血中可检测到独特的转录组与表观基因组改变”提供了概念验证。