Project description:The iconic giant panda is an endangered species known worldwide for its peculiar dietary habits. While retaining the digestive system of a carnivore, the giant panda successfully moved into a diet almost exclusively based on bamboo. Digestion of lignocellulose is believed to be conducted solely by its gut microbiome, provided that no lignocellulose-degrading enzyme was found in the giant panda’s genome. Many reports focused on which lignocellulose component feeds the giant panda, while little effort was made to link the products of bamboo fermentation to the panda’s dietary choices. In the present study, fermentation of either green leaves or yellow pith was conducted in the laboratory using gut microbiomes derived from either green or yellow stools, respectively. Green leaves were fermented to ethanol, lactate and acetate, while yellow pith to lactate resembling, respectively, hetero/homo-fermentation patterns. Several microbial pathways (assessed by metaproteomics) related to hemicellulose rather than cellulose degradation. However, alpha-amylases (E.C. 188.8.131.52) from the giant panda itself were the most predominant enzyme (up to 60% of all metaproteins), indicating that they have a primary role in bamboo digestion. The distinct fermentation profiles resulting from digestion of selected portions of bamboo may be part of the feeding strategy of giant pandas.
Project description:Gut microbiota dysbiosis characterizes systemic metabolic alteration, yet its causality is debated. To address this issue, we transplanted antibiotic-free conventional wild-type mice with either dysbiotic (“obese”) or eubiotic (“lean”) gut microbiota and fed them either a NC or a 72%HFD. We report that, on NC, obese gut microbiota transplantation reduces hepatic gluconeogenesis with decreased hepatic PEPCK activity, compared to non-transplanted mice. Of note, this phenotype is blunted in conventional NOD2KO mice. By contrast, lean microbiota transplantation did not affect hepatic gluconeogenesis. In addition, obese microbiota transplantation changed both gut microbiota and microbiome of recipient mice. Interestingly, hepatic gluconeogenesis, PEPCK and G6Pase activity were reduced even once mice transplanted with the obese gut microbiota were fed a 72%HFD, together with reduced fed glycaemia and adiposity compared to non-transplanted mice. Notably, changes in gut microbiota and microbiome induced by the transplantation were still detectable on 72%HFD. Finally, we report that obese gut microbiota transplantation may impact on hepatic metabolism and even prevent HFD-increased hepatic gluconeogenesis. Our findings may provide a new vision of gut microbiota dysbiosis, useful for a better understanding of the aetiology of metabolic diseases. all livers are from NC-fed mice only. Overall design: 6-wk-old C57Bl/6 male mice were fed a normal chow (NC) for 4 weeks. Mice have been transplanted with the vehicle (reduced PBS), or lean or obese gut microbiota. At the sacrifice by cervical dislocation, livers were dissected and snap-frozen in liquid nitrogen per each mouse.
Project description:Purpose:To present the miRNA expression profiles in giant panda milk exosomes across five lactation stages (0, 3, 7, 15 and 30 days after birth), aiming to provide new information for investigations into the physiological functions of the giant panda milk Methods: Three females were sampled in all, and each individual were sampled over multiple lactations, including 0, 3, 7, 15 and 30 days after delivery. Breast milk samples (5-10 ml) were collected from each stages. Total RNA isolated from individuals in five lactation stages (0, 7, 15 and 30 days after delivery) were pooled in equal quantities for each stage Results: Here, we illustrated the species and expression characteristics of exosome-loaded miRNAs existing in giant panda breast milk during distinct lactation periods, and highlighted the enrichment of immune- and development-related endogenous miRNAs in colostral and mature giant panda milk, which are stable even in certain hash conditions, like low pH and high concentration of RNAase, by the protection of extracellular vesicles.These findings indicate that breast milk may allow dietary intake of maternal miRNAs by infants for the regulation of postnatal development. We also demonstrated that the exogenous plant miRNA from the primary food source of giant panda (bamboo) were detected in the exosomes of giant panda breast milk, which were predicted to be of regulatory role in basic cell metabolism and neuron development. This result suggested that the dietary plant miRNAs were able to be absorbed by host cell and then secreted to body fluids as potential cross-kingdom regulators. Conclusions: Exosomal miRNAs in the giant panda breast milk may be the crucial maternal regulators for the development of intrinsic ‘slink’ newborn cubs. Overall design: Three females were sampled in all, and each individual were sampled over multiple lactations, including 0, 3, 7, 15 and 30 days after delivery. Breast milk samples (5-10 ml) were collected from each stages. Total RNA isolated from individuals in five lactation stages (0, 7, 15 and 30 days after delivery) were pooled in equal quantities for each stage.
Project description:The gut microbiota impacts many aspects of host biology including immune function. One hypothesis is that microbial communities induce epigenetic changes with accompanying alterations in chromatin accessibility, providing a mechanism that allows a community to have sustained host effects even in the face of its structural or functional variation. We used ATAC-seq to define chromatin accessibility in predicted enhancer regions of intestinal αβ+ and γδ+ intraepithelial lymphocytes (IELs) purified from germ-free mice, their conventionally-raised (CONV-R) counterparts, and mice reared GF and then colonized with a CONV-R gut microbiota at the end of the suckling-weaning transition. Characterizing genes adjacent to traditional enhancers and super-enhancers revealed signaling networks, metabolic pathways, and enhancer-associated transcription factors affected by the microbiota. Our results support the notion that epigenetic modifications help define microbial community-affiliated functional features of host immune cell lineages. Overall design: We interrogated chromatin accessibility using ATAC-seq in four cell types derived from mice (CD4+ T cells, CD8+ T cells, αβ+ intraepithelial lymphocytes, and γδ+ intraepithelial lymphocytes), across three gut microbial colonization states (germ-free, conventionally-raised, and conventionalized).
Project description:Advanced age is associated with chronic low-grade inflammation, which is usually referred to as inflammaging. Elderly are also known to have an altered gut microbiota composition. However, whether inflammaging is a cause or consequence of an altered gut microbiota composition is not clear. In this study gut microbiota from young or old conventional mice was transferred to young germ-free mice. Four weeks after gut microbiota transfer immune cell populations in spleen, Peyer’s patches, and mesenteric lymph nodes from conventionalized germ-free mice were analyzed by flow cytometry. In addition, whole-genome gene expression in the ileum was analyzed by microarray. Gut microbiota composition of donor and recipient mice was analyzed with 16S rDNA sequencing. Here we show by transferring aged microbiota to young germ-free mice that certain bacterial species within the aged microbiota promote inflammaging. This effect was associated with lower levels of Akkermansia and higher levels of TM7 bacteria and Proteobacteria in the aged microbiota after transfer. The aged microbiota promoted inflammation in the small intestine in the germ-free mice and enhanced leakage of inflammatory bacterial components into the circulation was observed. Moreover, the aged microbiota promoted increased T cell activation in the systemic compartment. In conclusion, these data indicate that the gut microbiota from old mice contributes to inflammaging after transfer to young germ-free mice. Overall design: Gut microbiota from young or old conventional mice was transferred to young germ-free mice. Four weeks after gut microbiota transfer whole-genome gene expression in the distal ileum was analyzed by microarray.
Project description:Chronic acid suppression by proton pump inhibitor (PPI) has been hypothesized to alter the gut microbiota via a change in intestinal pH. To evaluate the changes in gut microbiota composition by long-term PPI treatment. Twenty-four week old F344 rats were fed with (n = 5) or without (n = 6) lansoprazole (PPI) for 50 weeks. Then, profiles of luminal microbiota in the terminal ileum were analyzed. Pyrosequencing for 16S rRNA gene was performed by genome sequencer FLX (454 Life Sciences/Roche) and analyzed by metagenomic bioinformatics.
Project description:Improving immune function during aging contributes to the extension of healthspan. However, little is known about interventions for overcoming immunosenescence. Here, we investigated whether syringaresinol (SYR), an activator of FOXO3, overcomes immunosenescence and the factors associated with this effect. To address this, we administered SYR to 42-week-old mice for 10 weeks and analyzed immunological parameters and the gut microbiota. Compared to control mice, SYR-treated mice exhibited reversal of the age-related changes in lymphocyte subsets—such as CD3+ T, CD19+ B and Foxp3+ regulatory T (Treg) cells—and T-cell function in vitro. SYR induced the expression of Bim as well as the activation of FOXO3 in Tregs, which probably regulated Treg homeostasis. Furthermore, SYR reduced the serum level of lipopolysaccharide-binding protein, an inflammatory marker, and enriched the gut microbiota with beneficial bacteria, Lactobacillus and Bifidobacterium, effects that were closely associated with the changes in lymphocyte subsets. Finally, SYR enhanced humoral immunity against influenza vaccination to the level of young control mice. Collectively, these findings indicate that SYR may rejuvenate immunosenescence by enhancing the immune response and modulating the gut microbiota, possibly affecting systemic inflammation, although the precise mechanism awaits further study, and suggest SYR to be a potent candidate for anti-immunosenescence intervention. Overall design: Comparing the overall structural changes in the gut microbiota in young and old mice treated with vehicle, syringaresinol (SYR, 10 mg/kg or 50 mg/kg), or caloric restriction (CR) by bar-coded pyrosequencing of the V3 region of the 16S rRNA gene