孕期尼古丁暴露降低仔鼠睾丸类固醇生成:通过 nAChR/HDAC4 的表观遗传编程和遗传。

Reduced testicular steroidogenesis in rat offspring by prenatal nicotine exposure: Epigenetic programming and heritability via nAChR/HDAC4.

机构信息

Department of Pharmacology, Wuhan University School of Basic Medical Sciences, Wuhan, 430071, China.

Department of Pharmacology, Wuhan University School of Basic Medical Sciences, Wuhan, 430071, China; Basic Medical College of Nanyang Medical University, Nanyang, 473041, China.

出版信息

Food Chem Toxicol. 2020 Jan;135:111057. doi: 10.1016/j.fct.2019.111057. Epub 2019 Dec 14.

Abstract

Prenatal nicotine exposure (PNE) may lead to offspring's testicular dysplasia. Here, we confirmed the intergenerational effect of PNE on testosterone synthetic function and explored its epigenetic programming mechanism. Pregnant Wistar rats were injected subcutaneously with nicotine (2 mg/kg.d) from gestational day 9-20. Some dams were anesthetized to obtain fetal rats, the rest were allowed to spontaneous labor to generate F1 and F2 generation. In utero, PNE impaired testicular development and testosterone production. Meanwhile, the expression of steroidogenic acute regulatory protein (StAR) and 3β-hydroxysteroid dehydrogenase (3β-HSD) were decreased both in F1 and F2 generations. Furthermore, PNE enhanced the expression of fetal testicular nicotinic acetylcholine receptors (nAChRs) and histone deacetylase 4 (HDAC4), while obviously weakened histone 3 lysine 9 acetylation (H3K9ac) level of StAR/3β-HSD promoter from GD20 to postnatal week 12 and even in F2 generation. In vitro, nicotine increased nAChRs and HDAC4 expression, and decreased the StAR/3β-HSD H3K9ac level and expression, as well as the testosterone production in Leydig cells. Antagonism of nAChRs and inhibition of HDAC4 reversed the aforementioned changes. In conclusion, PNE programmed testicular low steroidogenesis and its heritability in male offspring rats. The underlying mechanism was associated to the low-level programming of StAR/3β-HSD H3K9ac via nAChR/HDAC4.

摘要

产前尼古丁暴露(PNE)可能导致后代睾丸发育不良。在这里,我们证实了 PNE 对睾酮合成功能的代际影响,并探讨了其表观遗传编程机制。从妊娠第 9 天到第 20 天,给怀孕的 Wistar 大鼠皮下注射尼古丁(2mg/kg.d)。一些母鼠被麻醉以获得胎儿大鼠,其余的则允许其自然分娩以产生 F1 和 F2 代。宫内,PNE 损害睾丸发育和睾酮产生。同时,F1 和 F2 代中类固醇生成急性调节蛋白(StAR)和 3β-羟甾脱氢酶(3β-HSD)的表达均降低。此外,PNE 增强了胎儿睾丸烟碱型乙酰胆碱受体(nAChRs)和组蛋白去乙酰化酶 4(HDAC4)的表达,同时明显减弱了从 GD20 到出生后第 12 周甚至 F2 代 StAR/3β-HSD 启动子的组蛋白 3 赖氨酸 9 乙酰化(H3K9ac)水平。在体外,尼古丁增加了 nAChRs 和 HDAC4 的表达,降低了 StAR/3β-HSD 的 H3K9ac 水平和表达,以及睾丸间质细胞的睾酮产生。nAChRs 的拮抗剂和 HDAC4 的抑制剂逆转了上述变化。总之,PNE 编程了雄性后代大鼠睾丸低类固醇生成及其遗传性。其潜在机制与通过 nAChR/HDAC4 对 StAR/3β-HSD H3K9ac 的低水平编程有关。

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