Butyricimonas

A Gram-negative, obligate anaerobic genus within the Bacteroidetes phylum (family Odoribacteraceae). Despite its relatively recent characterization, Butyricimonas has gained significant attention as a member of the protective butyrate-producing consortium that is consistently depleted in inflammatory and autoimmune conditions. Key species include B. virosa and B. synergistica.

Role in Gut Ecosystem

  • One of the few Bacteroidetes members that produces significant butyrate, placing it in an unusual metabolic niche — most Bacteroidetes produce acetate, propionate, or succinate rather than butyrate.
  • Butyrate production supports colonocyte energy metabolism, tight junction protein expression, and Treg differentiation via HDAC inhibition and GPR109A signaling.
  • Contributes to colonization resistance as part of the diverse anaerobic community that prevents pathogen expansion.
  • Name derives from "butyric acid" (butyrici-) and "unit" (monas), reflecting its defining metabolic feature.

Disease Associations

Multiple Sclerosis -- Key Depleted Taxon

  • Decreased in MS patients in the landmark Jangi 2016 study, which established the foundational MS-microbiome connection [1].
  • Butyricimonas abundance showed negative correlations with pro-inflammatory gene expression in circulating T cells and monocytes, including genes involved in dendritic cell maturation, interferon signaling, and nf kappa b signaling [1].
  • This is the inverse of the pattern seen with methanobrevibacter and akkermansia muciniphila, which were increased in MS and positively correlated with these inflammatory pathways [1].
  • Higher baseline abundance in MS patients reported in the Troci 2022 study (as part of broader Bacteroidetes expansion), illustrating study-to-study variability [2].
  • Dietary intake patterns strongly modulate Butyricimonas abundance in MS cohorts, suggesting responsiveness to nutritional interventions [3].

Antidepressant Response

  • Abundance altered by antidepressant medications (fluoxetine, amitriptyline), suggesting that drug-microbiome interactions modulate this genus [4].

Endometriosis

  • Identified among differentially abundant taxa in endometriosis-associated gut microbiome profiles [5].

Thyroid Disease

  • MR evidence links Butyricimonas to thyroid disease risk across multiple thyroid conditions [6].

Key Metabolites

  • Butyrate — primary product; anti-inflammatory HDAC inhibitor, colonocyte energy source, Treg inducer
  • Iso-butyrate — branched-chain fatty acid from protein fermentation

Mechanistic Significance in MS

The Jangi 2016 findings position Butyricimonas as a key anti-inflammatory species in MS:

  • Its negative correlation with interferon signaling genes suggests that butyrate from Butyricimonas may suppress the type I IFN response that drives MS pathology.
  • The anti-inflammatory effect parallels that of faecalibacterium prausnitzii but from within the Bacteroidetes phylum, providing taxonomic diversity in the butyrate-producing consortium.
  • Loss of Butyricimonas in MS may contribute to the reduced serum butyric acid levels and increased gut permeability documented in MS patients.

Key Sources

Connections

  • multiple sclerosis — depleted in MS; negative correlation with inflammatory gene expression
  • faecalibacterium prausnitzii — fellow butyrate producer; complementary anti-inflammatory role from Firmicutes
  • coprococcus — co-depleted butyrate producer in inflammatory disease
  • methanobrevibacter — shows opposite pattern in MS (increased); inflammatory correlations
  • short chain fatty acids — butyrate production is its defining metabolic feature
  • nf kappa b — butyrate suppresses NF-kB signaling in immune cells
  • inflammation — anti-inflammatory via butyrate-mediated HDAC inhibition and Treg induction
  • endometriosis — altered in endometriosis gut microbiome
  • graves disease — MR evidence links to thyroid disease risk
  • dysbiosis — depletion marks inflammatory dysbiosis across multiple conditions

References (6)

  1. Sushrut Jangi, Roopali Gandhi, Laura M. Cox et al. (2016). Alterations of the human gut microbiome in multiple sclerosis. Nature Communications. doi:10.1038/ncomms12015
  2. Alba Troci, Olga Zimmermann, Daniela Esser et al. (2022). B-cell-depletion reverses dysbiosis of the microbiome in multiple sclerosis patients. Scientific Reports. doi:10.1038/s41598-022-07336-8
  3. Matteo Bronzini, Alessandro Maglione, Rachele Rosso et al. (2023). Feeding the gut microbiome: impact on multiple sclerosis. Frontiers in Immunology. doi:10.3389/fimmu.2023.1176016
  4. Weijie Zhang, Wan Qu, Hua Wang et al. (2021). Antidepressants fluoxetine and amitriptyline induce alterations in intestinal microbiota and gut microbiome function in rats exposed to chronic unpredictable mild stress. Translational Psychiatry. doi:10.1038/s41398-021-01254-5
  5. Svensson A, Brunkwall L, Roth B et al. (2021). Associations Between Endometriosis and Gut Microbiota. Reproductive Sciences. doi:10.1007/s43032-021-00506-5
  6. Chen J, Wang Y, Yao H et al. (2024). Uncovering a Causal Connection between Gut Microbiota and Six Thyroid Diseases: A Two-Sample Mendelian Randomization Study. Biology. doi:10.3390/biology13090714

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