Jiamutai F N U, Hatfield Abigail, Herbert Austin, Majumdar Debarati, Shankar Vijay, Lackey Lela
Department of Genetics and Biochemistry, Center for Human Genetics, Clemson University, Clemson, USA.
Sci Rep. 2025 Jul 2;15(1):23510. doi: 10.1038/s41598-025-07569-3.
Alternative polyadenylation results in different 3' isoforms of messenger RNA (mRNA) transcripts. Alternative polyadenylation in the 3' untranslated region (3'UTR) can alter RNA localization, stability and translational efficiency. The SERPINA1 mRNA has two distinct 3' UTR isoforms, both of which express the protease inhibitor α-1-antitrypsin (A1AT). A1AT is an acute phase protein that is expressed and secreted from liver hepatocytes and upregulated during inflammation. Low levels of A1AT in the lung contributes to chronic obstructive pulmonary disease, while misfolding of A1AT in the liver contributes to liver cirrhosis. We analyzed the dynamics of alternative polyadenylation during cellular stress by treating the liver cell line HepG2 with the cytokine interleukin 6 (IL-6), ethanol or peroxide. SERPINA1 is transcriptionally upregulated after IL-6 treatment and has altered polyadenylation, resulting in an increase in long 3'UTR isoforms. We find that the long 3'UTR represses endogenous A1AT protein expression even with high levels of SERPINA1 mRNA. SERPINA1 expression and 3' end processing are not affected by ethanol or peroxide. IL-6-induced changes in transcriptome-wide transcriptional regulation suggest changes to the endoplasmic reticulum and in secretory protein processing. Our data shows that inflammation influences polyA site choice for SERPINA1 transcripts, resulting in reduced A1AT protein expression.
可变聚腺苷酸化导致信使核糖核酸(mRNA)转录本产生不同的3'异构体。3'非翻译区(3'UTR)中的可变聚腺苷酸化可改变RNA的定位、稳定性和翻译效率。丝氨酸蛋白酶抑制剂A1(SERPINA1)mRNA有两种不同的3'UTR异构体,二者均表达蛋白酶抑制剂α-1-抗胰蛋白酶(A1AT)。A1AT是一种急性期蛋白,由肝脏肝细胞表达并分泌,在炎症期间上调。肺中A1AT水平低会导致慢性阻塞性肺疾病,而肝脏中A1AT的错误折叠会导致肝硬化。我们通过用细胞因子白细胞介素6(IL-6)、乙醇或过氧化物处理肝癌细胞系HepG2,分析了细胞应激期间可变聚腺苷酸化的动态变化。IL-6处理后,SERPINA1转录上调且聚腺苷酸化发生改变,导致长3'UTR异构体增加。我们发现,即使SERPINA1 mRNA水平很高,长3'UTR也会抑制内源性A1AT蛋白的表达。SERPINA1的表达和3'末端加工不受乙醇或过氧化物的影响。IL-6诱导的全转录组转录调控变化表明内质网和分泌蛋白加工发生了变化。我们的数据表明,炎症会影响SERPINA1转录本的聚腺苷酸化位点选择,导致A1AT蛋白表达减少。