Farnesol induces protection against CNS inflammatory demyelination and decreases spinal infiltration of CD4+ T-Cells

Multiple Sclerosis (MS) is an autoimmune disease that causes T-cells to attack and degrade the myelin sheath of neurons in the spinal cord and brain. Farnesol is synthesized by plants and mammals and has anti-inflammatory along with neuroprotective activities. We used the MOG35–55 induced c57BL/6 murine EAE (experimental autoimmune encephalomyelitis) model due to model’s neurodegenerative and inflammatory properties. We predicted that farnesol would protect against EAE and increase autoimmunity markers. We collected spinal cords and spleens for flow cytometry analysis at the end of the study. This study found that farnesol significantly reduced spinal infiltration of CD4+ T cells, and increased infiltration of Tregs compared to untreated mice. Interestingly the proportion of CD25+Foxp3+ was increased compared to untreated mice, and statistically significant compared to vehicle treatment. We did not observe significant changes in CD4+, or CD25+Foxp3+ frequencies in the spleens. FOL treatment showed significant increase in CD11b+F4/80+ monocyte-derived macrophages (MDM) and F4/80int granulocytes/monocytes. FOL also showed significant weight retention and reduction of disease severity compared to untreated. These findings show that farnesol helps mediate the invasion of CD4+ T cells in the EAE model. Future studies should study how farnesol affects T-cell activation and differentiation, along with affects on macrophages and dendritic cells.

This work was supported in part by the National Institutes of Health (grant R15NS107743)

Microbiome methods in experimental autoimmune encephalomyelitis

Multiple Sclerosis (MS) is an autoimmune disease that affects the central nervous system (CNS) via neuroinflammation and demyelination. The exact triggers, subsets and effector mechanisms that contribute to disease progression are still largely unknown. Recent studies of healthy vs MS human stool samples indicated an altered microbiome, dysbiosis, which could lead to inflammation and disease. Experimental autoimmune encephalomyelitis (EAE) is a model used for the study of MS and can be induced in multiple non-rodent and rodent species. It is critical to control the environment of both the animal facility and experimental housing conditions in microbiome studies. We compared commercial vendors, Envigo and Jackson Laboratory, C57BL/6 female mice. Fecal samples were collected at Day 0, 14, and 21 for DNA extraction and sequencing of the ribosomal DNA (rDNA) to analyze the gut microbiome composition prior to and after induction of EAE. There was a significant difference between sources with Jackson Laboratory mice having an increased severity index compared to Envigo mice (p < 0.01) and a decreased survival rate of 20% when compared to 85% for Envigo mice. Our results suggest different sources of EAE mouse models have critical impacts on microbiome composition and levels of disease severity. Furthermore, this highlights the importance of consistent and controlled conditions from the animal model source, and throughout the experiment, when inducing EAE in mice and other animal models of disease.

This project was sponsored by NIH grant R15 NS107743. 

A GABA-producing probiotic for the protection of CNS demyelinating inflammation

The gut-microbiota-brain axis has emerged as a critical pathway in the regulation of neuroinflammation. The gut microbiome regulates the severity of many experimental models of autoimmune central nervous system (CNS) demyelinating inflammatory diseases. Our most recent findings demonstrate that the microbiota of mice from different sources affects the severity of CNS inflammatory demyelination. Neuroinflammation triggered in experimental autoimmune encephalomyelitis (EAE), a mouse model of multiple sclerosis, modified the gut microbiota composition. The disease progression resulted in a significant reduction in the relative abundances of members of lactic acid bacteria when compared to healthy control mice. Among the altered taxa, bacteria producing gamma-aminobutyric acid (GABA) were significantly reduced. We hypothesized that modifying the microbiota with a probiotic while increasing intestinal GABA levels would reduce EAE’s severity. We genetically engineered a Lactococcus lactis probiotic that produces excessed levels of GABA. Real-time quantitative PCR analysis demonstrated an elevated expression of glutamic acid decarboxylase (GAD). GABA-specific ELISA showed a significant increase in neurotransmitter production when exposed to increasing concentrations of glutamic acid and time. In vivo, five times/week oral gavages with 5 × 108 CFU/mouse of GAD L. lactis but not with empty-plasmid carrier L. lactis protects against EAE in mice compared with sham-treated mice and prevents weight loss of animals while modulating the microbiome’s composition. Our results show that the increase of GABA at the intestinal level with the oral treatment with a probiotic strain protects against neuroinflammation in the CNS.

Supported by grant from NIH (R15 NS107743)

Microbiome Methods in Experimental Autoimmune Encephalomyelitis

Microbiome composition studies are increasingly shedding light on animal models of disease. This paper describes a protocol for analyzing the gut microbiome composition prior to and after the induction of mice to experimental autoimmune encephalomyelitis (EAE), the principal animal model of the human neuroinflammatory demyelinating disease multiple sclerosis (MS). We also address and provide data assessing the impact of mice reared in different animal facilities on EAE induction. Furthermore, we discuss potential regulators of the gut-microbiome-brain axis (GMBA) in relation to neuroinflammation and implications on demyelinating disease states. Our results suggest that mice reared in different animal facilities produce different levels of EAE induction. These results highlight the importance of accounting for consistent environmental conditions when inducing EAE and other animal models of disease. © 2021 Wiley Periodicals LLC. Basic Protocol 1: Study of the composition of the gut microbiome in the neuroinflammatory model of experimental autoimmune encephalomyelitis Basic Protocol 2: Experimental procedures for DNA extraction and microbiome analysis.

The Microbiome as a Therapeutic Target for Multiple Sclerosis: Can Genetically Engineered Probiotics Treat the Disease?

There is an increasing interest in the intestinal microbiota as a critical regulator of the development and function of the immune, nervous, and endocrine systems. Experimental work in animal models has provided the foundation for clinical studies to investigate associations between microbiota composition and function and human disease, including multiple sclerosis (MS). Initial work done using an animal model of brain inflammation, experimental autoimmune encephalomyelitis (EAE), suggests the existence of a microbiota-gut-brain axis connection in the context of MS, and microbiome sequence analyses reveal increases and decreases of microbial taxa in MS intestines. In this review, we discuss the impact of the intestinal microbiota on the immune system and the role of the microbiome-gut-brain axis in the neuroinflammatory disease MS. We also discuss experimental evidence supporting the hypothesis that modulating the intestinal microbiota through genetically modified probiotics may provide immunomodulatory and protective effects as a novel therapeutic approach to treat this devastating disease.