PO.MCB06.02 · 分子与细胞生物学
早期生命肠道菌群编程肠道干细胞表观遗传以在晚年防止结肠癌
Early-life gut microbiota programs intestinal stem cell epigenetics to protect against colon cancer later in life
作者与单位 Authors & Affiliations
摘要 Abstract
中文摘要
背景：结直肠癌（CRC）由遗传和表观遗传改变共同引起。流行病学和动物研究表明，早期生命暴露（包括断奶期间的肠道菌群变化）可影响长期CRC风险。然而，将早期微生物相互作用与持久疾病保护相联系的机制仍不清楚。我们假设，早期微生物暴露对长寿的肠道干细胞（ISC）进行表观遗传编程，从而塑造免疫调控和疾病易感性。
方法：使用Lgr5-GFP报告小鼠在无特定病原体（SPF）和无菌（GF）条件下分离结肠ISC和肠上皮细胞（IEC）。进行全基因组亚硫酸氢盐测序（WGBS）和RNA测序，以评估从断奶到成年由DNA甲基化介导的菌群相关转录变化。肠道微生物移植（GMT）实验界定了ISC表观遗传对微生物影响最敏感的关键发育窗口期。结合鸟枪法宏基因组学的母体低剂量青霉素（LDP）模型识别出贡献表观遗传效应的特定细菌类群。使用葡聚糖硫酸钠（DSS）诱导的结肠炎和氧化偶氮甲烷（AOM）/DSS诱导的CRC模型评估长期后果。
结果：我们识别出683个在成年ISC和IEC中均与微生物组持续相关的差异甲基化区域（DMR）。其中，51%位于增强子中，且大多数DMR（79%）在SPF条件下表现出甲基化丢失。低甲基化基因富集于免疫和宿主防御功能，包括MHC II类基因（Cd74、H2-Aa、H2-Eb1和Ciita）。甲基化丢失发生在断奶后，并与基因表达增加相关。GMT实验证明，与青春期或成年期相比，断奶后是恢复甲基化模式的最佳窗口期。机制上，断奶期间一次短暂的IFN-gamma爆发通过IFN-gamma-STAT3-TET3轴驱动表观遗传重编程。此外，菌群来源的代谢物，包括短链脂肪酸（SCFA）、alpha-酮戊二酸（alpha-KG）和依赖甲硫氨酸-gamma-裂解酶的产物，强化了正确甲基化模式的建立。早期生命LDP暴露减少了革兰阳性细菌丰度，改变了IFN-gamma表达，破坏了MHC-II表观遗传，并增加了对结肠炎和CRC的易感性。
结论：早期生命的微生物和免疫信号建立了持久的表观遗传程序，可防止CRC。定时的微生物干预可能提供针对成年期发病疾病的持久保护。
查看英文原文 English abstract
Background : Colorectal cancer (CRC) arises from both genetic and epigenetic alterations. Epidemiological and animal studies suggest early-life exposures, including gut microbiota changes during weaning, can influence long-term CRC risk. However, the mechanisms linking early microbial interactions to durable disease protection remain unclear. We hypothesize that early microbial exposure epigenetically programs long-lived intestinal stem cells (ISCs), shaping immune regulation and disease susceptibility.
Methods: Lgr5-GFP reporter mice were used to isolate colonic ISCs and intestinal epithelial cells (IECs) under specific-pathogen-free (SPF) and germ-free (GF) conditions. Whole-genome bisulfite sequencing (WGBS) and RNA sequencing were performed to assess microbiota-associated transcriptional changes mediated by DNA methylation from weaning into adulthood. Gut microbe transplant (GMT) experiments defined the critical developmental window during which ISC epigenetics are most sensitive to microbial influences. A maternal low-dose penicillin (LDP) model combined with shotgun metagenomics identified specific bacterial taxa contributing to epigenetic effects. Dextran sulfate sodium (DSS)-induced colitis and azoxymethane (AOM)/DSS-induced CRC models were used to evaluate long-term consequences.
Results: We identified 683 differentially methylated regions (DMRs) that were persistently associated with the microbiome in both adult ISCs and IECs. Among these, 51% were located in enhancers, and the majority DMRs (79%) exhibited loss of methylation under SPF conditions. The hypomethylated genes were enriched for immune and host defense functions, including MHC class II genes ( Cd74 , H2-Aa , H2-Eb1 , and C iita ). Loss of methylation occurred post-weaning and correlated with increased gene expression. GMT experiments demonstrated the post-weaning as the optimal window to restore methylation patterns, compared to adolescence or adulthood. Mechanistically, a transient IFN-gamma burst during weaning drove epigenetic reprogramming via the IFN-gamma-STAT3-TET3 axis. In addition, microbiota-derived metabolites, including short-chain fatty acids (SCFAs), alpha-ketoglutarate (alpha-KG), and methionine-gamma-lyase-dependent products, reinforced the establishment of proper methylation patterns. Early-life LDP exposure reduced Gram-positive bacterial abundance, altered IFN-gamma expression, disrupted MHC-II epigenetics, and increased susceptibility to colitis and CRC.
Conclusion: Early-life microbial and immune signals establish durable epigenetic programs that protect against CRC. Timed microbial interventions may provide long-lasting protection against adult-onset diseases.
利益披露 Disclosure
L. Yang, None..
S. Zhou, None..
X. Chen, None..
F. Gutierrez, None..
S. Fowler, None..
L. Zhang, None..
J. M. Salamat, None..
K. Riggins, None..
J. Shi, None..
L. Shen, None.