PDF(Pubmed)
Abstract：
The active metabolite (S)-equol, derived from daidzein by gut microbiota, exhibits superior antioxidative activity compared with its precursor and plays a vital role in human health. As only 25% to 50% of individuals can naturally produce equol when supplied with isoflavone, we engineered probiotic E. coli Nissle 1917 (EcN) to convert dietary isoflavones into (S)-equol, thus offering a strategy to mimic the gut phenotype of natural (S)-equol producers. However, co-fermentation of EcN-eq with fecal bacteria revealed that gut microbial metabolites decreased NADPH levels, hindering (S)-equol production. Transcriptome analysis showed that the quorum-sensing (QS) transcription factor SdiA negatively regulates NADPH levels and (S)-equol biosynthesis in EcN-eq. Screening AHLs showed that SdiA binding to C10-HSL negatively regulates the pentose phosphate pathway, reducing intracellular NADPH levels in EcN-eq. Molecular docking and dynamics simulations investigated the structural disparities in complexes formed by C10-HSL with SdiA from EcN or E. coli K12. Substituting sdiA_EcN in EcN-eq with sdiA_K12 increased the intracellular NADPH/NADP+ ratio, enhancing (S)-equol production by 47%. These findings elucidate the impact of AHL-QS in the gut microbiota on EcN NADPH metabolism, offering insights for developing (S)-equol-producing EcN probiotics tailored to the gut environment.
摘要：
活性代谢物（S）-雌马酚，通过肠道微生物群从大豆苷元中提取，与其前体相比，表现出优异的抗氧化活性，对人类健康起着至关重要的作用。由于只有25％至50％的人可以自然产生雌马酚，当与异黄酮一起供应时，我们设计了益生菌大肠杆菌Nissle1917（EcN）将膳食异黄酮转化为（S）-雌马酚，从而提供了一种模拟天然（S）-雌马酚生产者的肠道表型的策略。然而,EcN-eq与粪便细菌的共发酵表明，肠道微生物代谢产物降低了NADPH水平，阻碍(S)-雌马酚的生产。转录组分析表明，群体感应（QS）转录因子SdiA负调节EcN-eq中的NADPH水平和（S）-雌马酚生物合成。筛选AHLs显示SdiA与C10-HSL结合负调控戊糖磷酸途径,降低EcN-eq中的细胞内NADPH水平。分子对接和动力学模拟研究了由C10-HSL与来自EcN或大肠杆菌K12的SdiA形成的复合物中的结构差异。用sdiA_K12代替EcN-eq中的sdiA_EcN增加了细胞内NADPH/NADP的比率，将(S)-雌马酚产量提高47%。这些发现阐明了肠道微生物群中AHL-QS对EcNNADPH代谢的影响，为开发适合肠道环境的（S）-雌马酚生产EcN益生菌提供见解。
