Gut Microbiome and Plasma Metabolome Signatures in Middle-Aged Mice With Cognitive Dysfunction Induced by Chronic Neuropathic Pain

Patients with chronic neuropathic pain (CNP) often complain about their terrible memory, especially the speed of information processing. Accumulating evidence suggests a possible link between gut microbiota and pain processing as well as cognitive function via the microbiota-gut-brain axis. This study aimed at exploring the fecal microbiome and plasma metabolite profiles in middle-aged spared nerve injury (SNI) mice model with cognitive dysfunction (CD) induced by CNP. The hierarchical cluster analysis of performance in the Morris water maze test was used to classify SNI mice with CD or without CD [i.e., non-CD (NCD)] phenotype. 16S rRNA sequencing revealed a lower diversity of gut bacteria in SNI mice, and the increase of Actinobacteria, Proteus, and Bifidobacterium might contribute to the cognitive impairment in the CNP condition. The plasma metabolome analysis showed that the endocannabinoid (eCB) system, disturbances of lipids, and amino acid metabolism might be the dominant signatures of CD mice. The fecal microbiota transplantation of the Sham (not CD) group improved allodynia and cognitive performance in pseudo-germ-free mice via normalizing the mRNA expression of eCB receptors, such as cn1r, cn2r, and htr1a, reflecting the effects of gut bacteria on metabolic activity. Collectively, the findings of this study suggest that the modulation of gut microbiota and eCB signaling may serve as therapeutic targets for cognitive deficits in patients with CNP.

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Vairimorpha Ceranae Alters Honey Bee Microbiota Composition and Sustain the Survival of Adult Honey Bees

10.21203/rs.3.rs-104567/v1 ◽

2020 ◽

Author(s):

Yakun Zhang ◽

Meiling Su ◽

Lon Wang ◽

Shaokang Huang ◽

Songkun Su ◽

...

Keyword(s):

Gut Microbiota ◽

Honey Bee ◽

Honey Bees ◽

Disease Transmission ◽

Alpha Diversity ◽

Gut Bacteria ◽

Post Inoculation ◽

Bacterial Populations ◽

Fecal Microbiome ◽

Bacterial Microbiota

Abstract Background: Vairimorpha (Nosema) ceranae is the most common eukaryotic gut pathogen in honey bees, Apis mellifera. Infection is typically chronic but may result in mortality. Additional factors may be involved in mortality, including the honey bee gut microbiota. Previous studies of V. ceranae and gut microbiota identified positive associations between core bacteria and V. ceranae infection. These possibly synergistic or mutualistic associations are often disregarded because some core bacteria act as probiotic symbionts. Methods: To clarify the effects caused by the positive associations, we added isomaltooligosaccharide (IMO), a prebiotic also found in honey, to alter the interactions between V. ceranae and gut bacteria. Mortality and sugar consumption of the caged bees were monitored. Infection intensities and gut bacteria were examed after 12 days post inoculation, the plateau phase of infection. The gut bacteria were evaluated using both qPCR and 16S rDNA sequencing.Results: We confirmed that V. ceranae infections alone significantly enhance several core bacterial populations, including Bifidobacterium spp., Snodgrassella alvi, and Gilliamella apicola in the honey bee hindgut microbiota. Moreover, the qPCR results suggested that V. ceranae infected bees had significantly higher bacterial microbiota populations. In addition to the enhanced core bacteria, Commensalibacter and Bartonella were significantly increased in the fecal microbiome. Infected bees fed IMO had significantly higher V. ceranae spore counts but lower mortality; however, infected bees fed IMO did not have significant changes in gut bacteria populations compared to those fed only sucrose, but feeding IMO further reduced the fecal microbiome alpha-diversity. Conclusions: The microbiota alterations caused by infection were similar to the microbiota differences found between summer bees and winter bees, the latter of which have longer lifespans, and feeding IMO increased this similarity. Our results indicated that the interactions between gut bacteria and V. ceranae not only enhanced both the pathogen and bacteria populations but also sustained the host survival. This mutualistic interaction potentially enhances disease transmission and avoids social immune responses of the honey bee hosts.

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Effect of Anesthesia/Surgery on Gut Microbiota and Fecal Metabolites and Their Relationship With Cognitive Dysfunction

Frontiers in Systems Neuroscience ◽

10.3389/fnsys.2021.655695 ◽

2021 ◽

Vol 15 ◽

Author(s):

Xinrong Lian ◽

Qianmei Zhu ◽

Li Sun ◽

Yaozhong Cheng

Keyword(s):

Gut Microbiota ◽

Cognitive Dysfunction ◽

Kynurenic Acid ◽

Serum Levels ◽

Inflammatory Factors ◽

Morris Water Maze Test ◽

Liquid Chromatography Mass Spectrometry ◽

Surgical Interventions ◽

The Central Nervous System ◽

Cognitive Disturbance

Aims: Post-operative cognitive dysfunction (POCD) is the decline in cognitive function of the central nervous system (CNS) after anesthesia/surgery. The present study explored whether anesthesia/surgery altered gut microbiota and fecal metabolites, examining their associations with risk factors of cognitive dysfunction in aged mice.Methods: Sixteen-month-old C57BL/6 mice underwent abdominal surgery under isoflurane anesthesia to establish an animal model of POCD. The Morris water maze test (MWMT) was used as an indicator of memory after surgery. The effects of anesthesia/surgical interventions on gut microbiota, fecal metabolites, hippocampus, and serum levels of inflammatory factors were examined.Results: The anesthesia/surgery induced more serious POCD behavior, increasing brain interleukin (IL)-6, and IL-1β levels than sham control mice. The relative abundance of bacterial genera Bacteroidales_unclassified, Mucispirillum, and Clostridiales_unclassified declined, whereas that of Escherichia–Shigella, actinomyces, Ruminococcus_gnavus_group, and Lachnospiraceae_FCS020_group were enriched after anesthesia/surgery compared to the baseline controls. Liquid chromatography–mass spectrometry (LC–MS) showed that the metabolites differed between post-anesthesia+surgery (post_A + S) and baseline samples and were associated with the fecal metabolism of tryptophan, kynurenic acid, N-oleoyl γ-aminobutyric acid (GABA), 2-indolecarboxylic acid, and glutamic acid. Furthermore, the differential metabolites were associated with alterations in the abundance of specific bacteria. These results indicate that the POCD intervention may be achieved by targeting specific bacteria associated with neurotransmitter metabolism.Conclusions: A transient cognitive disturbance induced by anesthesia/surgery may be associated with unfavorable alterations in gut microbiota and fecal metabolites, thereby contributing to the POCD development.

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