基于16S rDNA测序的肠道菌群探讨解郁祛痰化浊方对高脂饮食大鼠肠-肝轴的影响

目的 研究解郁祛痰化浊方（JQHP）对高脂饮食大鼠肠道菌群的影响，探讨中药调控肠道微生物群进而恢复肠-肝轴的平衡。方法 将70只雄性SPF级别Wistar大鼠随机分为正常组（10只）与模型组（60只），正常组饲喂正常饲料，模型组饲喂高脂饲料。12周后将模型组随机分为6组，每组10只，即模型组，血脂康组，立普妥组，JQHP低、中、高剂量组。JQHP低、中、高剂量组分别灌胃JQHP颗粒剂0.4，0.8，1.6 g·kg^-1，立普妥组予立普妥2 mg·kg^-1，血脂康组予血脂康0.1 g·kg^-1，正常组和模型组大鼠灌胃同等量蒸馏水，连续灌胃8周后收集粪便，进行16S rRNA基因测序，行腹主动脉取血检测血脂，取肝脏组织及回肠组织苏木素-伊红（HE）染色后进行病理形态学观察。结果 与正常组比较，模型组大鼠血脂四项总胆固醇（TC），甘油三酯（TG），低密度脂蛋白胆固醇（LDL-C）均见明显升高，高密度脂蛋白胆固醇（HDL-C）降低（P<0.01）；与模型组比较，血脂康组、立普妥组TC，TG显著性下降（P<0.01），血脂康组HDL-C升高（P<0.05）。JQHP中剂量组较模型组对肝脏脂肪样变有一定的缓解作用，可以减轻炎性细胞的浸润情况。JQHP可使回肠结构淋巴组织增生情况好转，且中剂量组疗效最显著。Shannon曲线结果表明，与正常组比较，JQHP中剂量组显著提高（P<0.01）；与模型组比较，JQHP中、高剂量组明显升高（P<0.05，P<0.01）；与JQHP中剂量组比较，其他用药组降低（P<0.05，P<0.01）。主成分多样性分析（PCA）示中药中剂量组多样性和丰度高于其他用药组。线性判别分析（LDA）中，与正常组比较，模型组拟杆菌纲，瘤胃球菌科，拟杆菌S24-7，瘤胃球菌UCG-005下调（P<0.01），脱硫弧菌目、丹毒丝菌目、毛螺菌科上调（P<0.05，P<0.01）。与模型组比较，JQHP中剂量组的拟杆菌纲，瘤胃球菌科，拟杆菌S24-7，瘤胃球菌UCG-005上调（P<0.05，P<0.01），丹毒丝菌目下调（P<0.01）。与JQHP中剂量组比较，其他用药组拟杆菌纲，瘤胃球菌科，拟杆菌S24-7，瘤胃球菌UCG-005中降低（P<0.05，P<0.01），在丹毒丝菌目、毛螺菌科中升高（P<0.05，P<0.01）。结论 JQHP调整肠道物种丰度和多样性，改善肝脏组织和回肠黏膜状态，调节血脂水平，恢复正常肠道生态环境，可能与调节与炎症相关的肠道菌群而恢复肠-肝轴平衡有关，以中剂量组效果最佳。     

The effects of the microbiota on the host immune system

Abstract

The human gastrointestinal track harbors hundreds of species of commensal organisms, collectively known as microbiota. The composition of the intestinal microbiota is changeable by various factors, such as host genotype, diet, antibiotics, pathogen infections, among others. Changes in these factors can cause microbiome disruption known as dysbiosis, leading to the outgrowth of potential pathogenic bacteria or decrease in the number of beneficial bacteria. Dysbiosis has been implicated in numerous inflammatory and autoimmune diseases. This review is focused on host–microbiota interactions, specifically on influence of bacterial-derived signals on immune cell function and the mechanisms by which these signals modulate the development and progression of inflammatory and autoimmune diseases.     

Skin sensitivity and skin microbiota: Is there a link?

Sensitive skin is defined by the occurrence of unpleasant sensations, accompanied or not by erythema, in response to stimuli which normally should not provoke such sensations and that cannot be linked to skin disease. Even if its pathophysiology is not completely known, hyper‐reactivity of the cutaneous nervous system associated with an abnormal skin barrier has been hypothesized as a primary culprit including more recently a role of the cutaneous microbiota. The objective of this short review is to discuss the relationship between the skin microbiota, skin sensitivity and the skin barrier function.     

Antimicrobial peptides play a functional role in bumblebee anti-trypanosome defense

Bumblebees, amongst the most important of pollinators, are under enormous population pressures. One of these is disease. The bumblebee and its gut trypanosome Crithidia bombi are one of the fundamental models of ecological immunology. Although there is previous evidence of increased immune gene expression upon Crithidia infection, recent work has focussed on the bumblebee’s gut microbiota. Here, by knocking down gene expression using RNAi, we show for the first time that antimicrobial peptides (AMPs) have a functional role in anti-Crithidia defense.     

Gut microbiota as a source of a surrogate antigen that triggers autoimmunity in an immune privileged site

Recent discoveries on the role of commensal microbiota have significantly changed our understanding of human physiology. The host-microbiota interplay is now an important aspect to take into account to understand immune responses and immunological diseases. Autoimmune uveitis is a sight-threatening disease that arises without a known infectious etiology. It is unknown where and how autoreactive T cells become primed to trigger disease in the eye, which is an immune privileged site. We recently reported data supporting the notion that retina-specific T cells receive a signal in the gut from commensal microbiota-derived cross-reactive antigen(s) and trigger autoimmune uveitis in the R161H mouse model. Here we discuss our published findings, as well as our recent attempts to identify the responsible microbe(s) by using different antibiotic treatments, 16S rDNA sequencing and homology searches for candidate antigenic mimic(s) of the retinal antigen.     

Autism spectrum disorders and intestinal microbiota

Through extensive microbial-mammalian co-metabolism, the intestinal microbiota have evolved to exert a marked influence on health and disease via gut-brain-microbiota interactions. In this addendum, we summarize the findings of our recent study on the fecal microbiota and metabolomes of children with pervasive developmental disorder–not otherwise specified (PDD-NOS) or autism (AD) compared with healthy children (HC). Children with PDD-NOS or AD have altered fecal microbiota and metabolomes (including neurotransmitter molecules). We hypothesize that the degree of microbial alteration correlates with the severity of the disease since fecal microbiota and metabolomes alterations were higher in children with PDD-NOS and, especially, AD compared to HC. Our study indicates that the levels of free amino acids (FAA) and volatile organic compounds (VOC) differ in AD subjects compared to children with PDD-NOS, who are more similar to HC. Finally, we propose a new perspective on the implications for the interaction between intestinal microbiota and AD.     

Bacterial adaptation to the gut environment favors successful colonization

Rodent models harboring a simple yet functional human intestinal microbiota provide a valuable tool to study the relationships between mammals and their bacterial inhabitants. In this study, we aimed to develop a simplified gnotobiotic mouse model containing 10 easy-to-grow bacteria, readily available from culture repositories, and of known genome sequence, that overall reflect the dominant commensal bacterial makeup found in adult human feces. We observed that merely inoculating a mix of fresh bacterial cultures into ex-germ free mice did not guarantee a successful intestinal colonization of the entire bacterial set, as mice inoculated simultaneously with all strains only harbored 3 after 21 d. Therefore, several inoculation procedures were tested and levels of individual strains were quantified using molecular tools. Best results were obtained by inoculating single bacterial strains into individual animals followed by an interval of two weeks before allowing the animals to socialize to exchange their commensal microbes. Through this procedure, animals were colonized with almost the complete bacterial set (9/10). Differences in the intestinal composition were also reflected in the urine and plasma metabolic profiles, where changes in lipids, SCFA, and amino acids were observed. We conclude that adaptation of bacterial strains to the host’s gut environment (mono-colonization) may predict a successful establishment of a more complex microbiota in rodents.     

A dysbiotic subpopulation of alcohol-dependent subjects

The vast majority of studies that assessed the importance of biological factors for the development of psychiatric disorders focused on processes occurring at the brain level. Alcohol-dependence is a very frequent psychiatric disorder where psycho-pharmacological interventions are only of moderate efficacy. Our laboratory has recently described that a subpopulation of alcohol-dependent subjects, that accounted for approximately 40% of individuals tested, presented with an increased intestinal permeability, with a dysbiosis, with alterations in the metabolomic content of faeces - that could play a role in the increased permeability - and finally with a more severe profile of alcohol-dependence than the other non-dysbiotic subpopulation. In this addendum, we discuss the implications of our observations for the pathophysiology of alcohol dependence where we try to discriminate which addiction dimensions are likely related to the gut microbiota alterations and whether these alterations are the cause or the consequence of drinking habits.     

Advancing the use of Lactobacillus acidophilus surface layer protein A for the treatment of intestinal disorders in humans

Intestinal immunity is subject to complex and fine-tuned regulation dictated by interactions of the resident microbial community and their gene products with host innate cells. Deterioration of this delicate process may result in devastating autoinflammatory diseases, including inflammatory bowel disease (IBD), which primarily comprises Crohn's disease (CD) and ulcerative colitis (UC). Efficacious interventions to regulate proinflammatory signals, which play critical roles in IBD, require further scientific investigation. We recently demonstrated that rebalancing intestinal immunity via the surface layer protein A (SlpA) from Lactobacillus acidophilus NCFM potentially represents a feasible therapeutic approach to restore intestinal homeostasis. To expand on these findings, we established a new method of purifying bacterial SlpA, a new SlpA-specific monoclonal antibody, and found no SlpA-associated toxicity in mice. Thus, these data may assist in our efforts to determine the immune regulatory efficacy of SlpA in humans.