MedicalResearch.com Interview with: [caption id="attachment_38492" align="alignleft" width="170"] Dr. Kouichi Ito[/caption] Kouichi Ito, PhD Associate Professor Department of Neurology Robert Wood Johnson Medical School Rutgers MedicalResearch.com: What is the background for this study? What are the main findings? Response: Multiple Sclerosis (MS) is an autoimmune disease of the central nervous system (CNS), and breakdown of immune tolerance to CNS proteins has been suggested to initiate CNS autoimmunity. Although the mechanism underlying the breakdown of immune tolerance to CNS proteins is still unknown, gut microbiota has been suggested to be involved in disease initiation and progression. To investigate the etiology of Multiple Sclerosis, we have created humanized transgenic mice expressing MHC class II and T cell receptor genes isolated from an Multiple Sclerosis patient and showed that gut dysbiosis, alteration in intestinal microbial composition, can induce gut leakiness and subsequently trigger the development of neurological deficits through activation of complement C3 and reduction of CBLB and Foxp3 genes. This study suggests that gut dysbiosis is one of the possible etiological factors for Multiple Sclerosis.

MedicalResearch.com Interview with: [caption id="attachment_23164" align="alignleft" width="85"] Prof. John Cryan[/caption] Professor JF Cryan PhD Department of Anatomy and Neuroscience APC Microbiome Institute University College Cork Cork, Ireland MedicalResearch.com: What is the background for this study? What are the main findings?  Prof. Cryan: Over the past decade there has been an ever growing body of preclinical studies that highlight an essential role of the gut microbiota in many aspects of physiology including and perhps most surprtisingly the brain . Germ-free animals are one useful approach used to establish causality in gut microbiota-brain relationships. This model has been extremely useful in establishing that the microbiota is essential for appropriate stress responsibility, anxiety-like behaviours, neurogenesis, blood-brain barrier function and microglia activity. From these findings we can see that there is a clear cut role for the microbiota in CNS developmental processes. Here we wanted to investigate using next generation sequencing, as we had done previously in the amygdala what impact life without microbes has on transcriptional regulation in the prefrontal cortex, a brain region essential in many aspects of emotional behaviour. What we uncovered from this was that there was a large number of dysregulated genes in germ-free animals that have a direct role in myelination. We found increased expression levels of genes that encode for structural proteins that are key in forming the myelin sheath. We followed up this finding with transmission electron microscopy to identify whether this marked increase in myelin related gene expression was functional at a structural level. What we found was germ-free myelinated axons in the prefrontal cortex were hypermyelinated (lower g-ratio), they had thicker myelin sheaths compared to conventionally raised mice. Additionally we also had germ-free colonized animals, animals that were born germ-free but have been colonized with a conventional microbiome early in life. These animals displayed no change in myelin related gene expression and appeared to be indistinguishable from the conventional animals. However, at the protein levels they appeared to have increased myelin protein like germ-free mice. This could be due to the fact that these mice were germ-free for at least 3 weeks of life and the hypermyelinated axons had already been established before colonization. Really this shows that we can still target the microbiota in later life that can have an impact of myelin gene regulation.