Digestive Health Research Institute, Case Western Reserve University School of Medicine, Cleveland, OH, United States; Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH, United States.
Digestive Health Research Institute, Case Western Reserve University School of Medicine, Cleveland, OH, United States; Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, OH, United States.
Brain Behav Immun. 2021 Nov;98:245-250. doi: 10.1016/j.bbi.2021.08.218. Epub 2021 Aug 14.
Patients with inflammatory bowel disease (IBD) are particularly susceptible to behavioral diagnoses, and the microbiome has been repeatedly implicated in the pathogenesis of IBD. The intestinal microbiome's ability to affect behavior has become increasingly recognized and studied. The so-called 'psychobiome' has been linked to a plethora of neurological and psychological diagnoses, including autism and Parkinson's disease. Despite the ability of many bacterial species within the human intestinal microbiome to synthesize neurotransmitters, it has never been previously reported that a single bacterial species is sufficient to induce depression. Here, we demonstrate that our mouse model of Crohn's disease (CD)-like ileitis, the SAMP1/YitFc (SAMP1), does not exhibit baseline behavioral abnormalities. By comparison, SAMP6 mice develop depressive-like behavior that is associated with a rise in the GABA-producing bacterial genus Parabacteroides. We finally demonstrate that administration of Parabacteroides distasonis into our SAMP1 mice induces depressive-like behavior. Colonization with P. distasonis was not associated with increased intestinal inflammation or alterations in other measures of behavior. The intestinal environment of CD may be particularly conducive to colonization with P. distasonis and subsequent induction of depressive-like behavior. To our knowledge, this is the first report of a bacterial species specifically inducing depressive-like behavior.
炎症性肠病（IBD）患者特别容易出现行为诊断，而微生物组已被反复牵涉到 IBD 的发病机制中。肠道微生物组影响行为的能力已得到越来越多的认可和研究。所谓的“心理微生物组”与许多神经和心理诊断有关，包括自闭症和帕金森病。尽管人类肠道微生物组中的许多细菌种类都能够合成神经递质，但以前从未有报道称单一细菌种类足以引发抑郁症。在这里，我们证明了我们的类似克罗恩病（CD）的回肠炎 SAMP1/YitFc（SAMP1）小鼠模型没有表现出基线行为异常。相比之下，SAMP6 小鼠表现出抑郁样行为，这与产生 GABA 的细菌属 Parabacteroides 的增加有关。我们最后证明，将 Parabacteroides distasonis 施用于我们的 SAMP1 小鼠会诱导出抑郁样行为。P. distasonis 的定植与肠道炎症的增加或其他行为测量的改变无关。CD 的肠道环境可能特别有利于 P. distasonis 的定植和随后诱导的抑郁样行为。据我们所知，这是第一个报道特定细菌种类诱导抑郁样行为的报告。
