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Microbial bile acid metabolites modulate gut ROR gamma(+) regulatory T cell homeostasis 期刊论文
NATURE, 2020, 577 (7790) : 410-+
作者:  Bhargava, Manjul
收藏  |  浏览/下载:38/0  |  提交时间:2020/07/03

The metabolic pathways encoded by the human gut microbiome constantly interact with host gene products through numerous bioactive molecules(1). Primary bile acids (BAs) are synthesized within hepatocytes and released into the duodenum to facilitate absorption of lipids or fat-soluble vitamins(2). Some BAs (approximately 5%) escape into the colon, where gut commensal bacteria convert them into various intestinal BAs2 that are important hormones that regulate host cholesterol metabolism and energy balance via several nuclear receptors and/or G-protein-coupled receptors(3,4). These receptors have pivotal roles in shaping host innate immune responses(1,5). However, the effect of this host-microorganism biliary network on the adaptive immune system remains poorly characterized. Here we report that both dietary and microbial factors influence the composition of the gut BA pool and modulate an important population of colonic FOXP3(+) regulatory T (T-reg) cells expressing the transcription factor ROR gamma. Genetic abolition of BA metabolic pathways in individual gut symbionts significantly decreases this T-reg cell population. Restoration of the intestinal BA pool increases colonic ROR gamma(+) T-reg cell counts and ameliorates host susceptibility to inflammatory colitis via BA nuclear receptors. Thus, a pan-genomic biliary network interaction between hosts and their bacterial symbionts can control host immunological homeostasis via the resulting metabolites.


  
A neurotransmitter produced by gut bacteria modulates host sensory behaviour 期刊论文
NATURE, 2020
作者:  Zhao, Xiaoxu;  Song, Peng;  Wang, Chengcai;  Riis-Jensen, Anders C.;  Fu, Wei;  Deng, Ya;  Wan, Dongyang;  Kang, Lixing;  Ning, Shoucong;  Dan, Jiadong;  Venkatesan, T.;  Liu, Zheng;  Zhou, Wu;  Thygesen, Kristian S.;  Luo, Xin;  Pennycook, Stephen J.;  Loh, Kian Ping
收藏  |  浏览/下载:38/0  |  提交时间:2020/07/03

A neuromodulator produced by commensalProvidenciabacteria that colonize the gut ofCaenorhabditis elegansmimics the functions of the cognate host molecule to manipulate a sensory decision of the host.


Animals coexist in commensal, pathogenic or mutualistic relationships with complex communities of diverse organisms, including microorganisms(1). Some bacteria produce bioactive neurotransmitters that have previously been proposed to modulate nervous system activity and behaviours of their hosts(2,3). However, the mechanistic basis of this microbiota-brain signalling and its physiological relevance are largely unknown. Here we show that inCaenorhabditis elegans, the neuromodulator tyramine produced by commensalProvidenciabacteria, which colonize the gut, bypasses the requirement for host tyramine biosynthesis and manipulates a host sensory decision. Bacterially produced tyramine is probably converted to octopamine by the host tyramine beta-hydroxylase enzyme. Octopamine, in turn, targets the OCTR-1 octopamine receptor on ASH nociceptive neurons to modulate an aversive olfactory response. We identify the genes that are required for tyramine biosynthesis inProvidencia, and show that these genes are necessary for the modulation of host behaviour. We further find thatC. eleganscolonized byProvidenciapreferentially select these bacteria in food choice assays, and that this selection bias requires bacterially produced tyramine and host octopamine signalling. Our results demonstrate that a neurotransmitter produced by gut bacteria mimics the functions of the cognate host molecule to override host control of a sensory decision, and thereby promotes fitness of both the host and the microorganism.


  
A plant genetic network for preventing dysbiosis in the phyllosphere 期刊论文
NATURE, 2020, 580 (7805) : 653-+
作者:  van den Brink, Susanne C.;  Alemany, Anna;  van Batenburg, Vincent;  Moris, Naomi;  Blotenburg, Marloes;  Vivie, Judith;  Baillie-Johnson, Peter;  Nichols, Jennifer;  Sonnen, Katharina F.;  Martinez Arias, Alfonso;  van Oudenaarden, Alexander
收藏  |  浏览/下载:79/0  |  提交时间:2020/07/03

Mutations in genes involved in immune signalling and vesicle trafficking cause defects in the leaf microbiome of Arabidopsis thaliana that result in damage to leaf tissues, suggesting mechanisms by which terrestrial plants control the level and diversity of endophytic phyllosphere microbiota.


The aboveground parts of terrestrial plants, collectively called the phyllosphere, have a key role in the global balance of atmospheric carbon dioxide and oxygen. The phyllosphere represents one of the most abundant habitats for microbiota colonization. Whether and how plants control phyllosphere microbiota to ensure plant health is not well understood. Here we show that the Arabidopsis quadruple mutant (min7 fls2 efr cerk1  hereafter, mfec)(1), simultaneously defective in pattern-triggered immunity and the MIN7 vesicle-trafficking pathway, or a constitutively activated cell death1 (cad1) mutant, carrying a S205F mutation in a membrane-attack-complex/perforin (MACPF)-domain protein, harbour altered endophytic phyllosphere microbiota and display leaf-tissue damage associated with dysbiosis. The Shannon diversity index and the relative abundance of Firmicutes were markedly reduced, whereas Proteobacteria were enriched in the mfec and cad1(S205F) mutants, bearing cross-kingdom resemblance to some aspects of the dysbiosis that occurs in human inflammatory bowel disease. Bacterial community transplantation experiments demonstrated a causal role of a properly assembled leaf bacterial community in phyllosphere health. Pattern-triggered immune signalling, MIN7 and CAD1 are found in major land plant lineages and are probably key components of a genetic network through which terrestrial plants control the level and nurture the diversity of endophytic phyllosphere microbiota for survival and health in a microorganism-rich environment.


  
Dietary fructose feeds hepatic lipogenesis via microbiota-derived acetate 期刊论文
NATURE, 2020, 579 (7800) : 586-+
作者:  Ng, Andrew H.;  Nguyen, Taylor H.;  Gomez-Schiavon, Mariana;  Dods, Galen;  Langan, Robert A.;  Boyken, Scott E.;  Samson, Jennifer A.;  Waldburger, Lucas M.;  Dueber, John E.;  Baker, David;  El-Samad, Hana
收藏  |  浏览/下载:47/0  |  提交时间:2020/07/03

A genetic mouse model is used to reveal a two-pronged mechanism of fructose-induced de novo lipogenesis in the liver, in which fructose catabolism in hepatocytes provides a signal to promote lipogenesis, whereas fructose metabolism by the gut microbiota provides acetate as a substrate to feed lipogenesis.


Consumption of fructose has risen markedly in recent decades owing to the use of sucrose and high-fructose corn syrup in beverages and processed foods(1), and this has contributed to increasing rates of obesity and non-alcoholic fatty liver disease(2-4). Fructose intake triggers de novo lipogenesis in the liver(4-6), in which carbon precursors of acetyl-CoA are converted into fatty acids. The ATP citrate lyase (ACLY) enzyme cleaves cytosolic citrate to generate acetyl-CoA, and is upregulated after consumption of carbohydrates(7). Clinical trials are currently pursuing the inhibition of ACLY as a treatment for metabolic diseases(8). However, the route from dietary fructose to hepatic acetyl-CoA and lipids remains unknown. Here, using in vivo isotope tracing, we show that liver-specific deletion of Acly in mice is unable to suppress fructose-induced lipogenesis. Dietary fructose is converted to acetate by the gut microbiota(9), and this supplies lipogenic acetyl-CoA independently of ACLY(10). Depletion of the microbiota or silencing of hepatic ACSS2, which generates acetyl-CoA from acetate, potently suppresses the conversion of bolus fructose into hepatic acetyl-CoA and fatty acids. When fructose is consumed more gradually to facilitate its absorption in the small intestine, both citrate cleavage in hepatocytes and microorganism-derived acetate contribute to lipogenesis. By contrast, the lipogenic transcriptional program is activated in response to fructose in a manner that is independent of acetyl-CoA metabolism. These data reveal a two-pronged mechanism that regulates hepatic lipogenesis, in which fructolysis within hepatocytes provides a signal to promote the expression of lipogenic genes, and the generation of microbial acetate feeds lipogenic pools of acetyl-CoA.


  
Microbiome analyses of blood and tissues suggest cancer diagnostic approach 期刊论文
NATURE, 2020, 579 (7800) : 567-+
作者:  Shao, Zhengping;  Flynn, Ryan A.;  Crowe, Jennifer L.;  Zhu, Yimeng;  Liang, Jialiang;  Jiang, Wenxia;  Aryan, Fardin;  Aoude, Patrick;  Bertozzi, Carolyn R.;  Estes, Verna M.;  Lee, Brian J.;  Bhagat, Govind;  Zha, Shan;  Calo, Eliezer
收藏  |  浏览/下载:92/0  |  提交时间:2020/07/03

Microbial nucleic acids are detected in samples of tissues and blood from more than 10,000 patients with cancer, and machine learning is used to show that these can be used to discriminate between and among different types of cancer, suggesting a new microbiome-based diagnostic approach.


Systematic characterization of the cancer microbiome provides the opportunity to develop techniques that exploit non-human, microorganism-derived molecules in the diagnosis of a major human disease. Following recent demonstrations that some types of cancer show substantial microbial contributions(1-10), we re-examined whole-genome and whole-transcriptome sequencing studies in The Cancer Genome Atlas(11) (TCGA) of 33 types of cancer from treatment-naive patients (a total of 18,116 samples) for microbial reads, and found unique microbial signatures in tissue and blood within and between most major types of cancer. These TCGA blood signatures remained predictive when applied to patients with stage Ia-IIc cancer and cancers lacking any genomic alterations currently measured on two commercial-grade cell-free tumour DNA platforms, despite the use of very stringent decontamination analyses that discarded up to 92.3% of total sequence data. In addition, we could discriminate among samples from healthy, cancer-free individuals (n = 69) and those from patients with multiple types of cancer (prostate, lung, and melanoma  100 samples in total) solely using plasma-derived, cell-free microbial nucleic acids. This potential microbiome-based oncology diagnostic tool warrants further exploration.


  
Minor increases in Phyllostachys edulis (Moso bamboo) biomass despite evident alterations of soil bacterial community structure after phosphorus fertilization alone: Based on field studies at different altitudes 期刊论文
FOREST ECOLOGY AND MANAGEMENT, 2019, 451
作者:  Zhang, Manyun;  Zhang, Wenyuan;  Bai, Shahla Hosseini;  Niu, Yun;  Hu, Dongnan;  Ji, Hanrui;  Xu, Zhihong
收藏  |  浏览/下载:34/0  |  提交时间:2019/11/27
Moso bamboo  P fertilization  Altitudes  Soil microorganism  Illumina HiSeq sequencing  
Soil aggregates as biogeochemical reactors and implications for soil-atmosphere exchange of greenhouse gases-A concept 期刊论文
GLOBAL CHANGE BIOLOGY, 2019, 25 (2) : 373-385
作者:  Wang, Bin;  Brewer, Paul E.;  Shugart, Herman H.;  Lerdau, Manuel T.;  Allison, Steven D.
收藏  |  浏览/下载:21/0  |  提交时间:2019/04/09
aggregate reactor  aggregate-based model  greenhouse gas  individual-based model  microorganism  soil heterogeneity  soil organic matter