A novel probiotic mixture exerts a therapeutic effect on experimental autoimmune encephalomyelitis mediated by IL-10 producing regulatory T cells

Reduction of Abeta amyloid pathology in APPPS1 transgenic mice in the absence of gut microbiota

Alzheimer’s disease is the most common form of dementia in the western world, however there is no cure available for this devastating neurodegenerative disorder. Despite clinical and experimental evidence implicating the intestinal microbiota in a number of brain disorders, its impact on Alzheimer’s disease is not known. To this end we sequenced bacterial 16S rRNA from fecal samples of Aβ precursor protein (APP) transgenic mouse model and found a remarkable shift in the gut microbiota as compared to non-transgenic wild-type mice. Subsequently we generated germ-free APP transgenic mice and found a drastic reduction of cerebral Aβ amyloid pathology when compared to control mice with intestinal microbiota. Importantly, colonization of germ-free APP transgenic mice with microbiota from conventionally-raised APP transgenic mice increased cerebral Aβ pathology, while colonization with microbiota from wild-type mice was less effective in increasing cerebral Aβ levels. Our results indicate a microbial involvement in the development of Abeta amyloid pathology, and suggest that microbiota may contribute to the development of neurodegenerative diseases.

Effects of Gender and Age on Immune Responses of Human Peripheral Blood Mononuclear Cells to Probiotics: A Large Scale Pilot Study

BACKGROUND

Despite the widely accepted concept that probiotics confer miscellaneous benefits to hosts, the controversies surrounding these health-promoting claims cannot be ignored. These controversies hinder development and innovation in this field.

RESULTS

To clarify the effects of age and gender on probiotic-induced immune responses, we recruited 1613 Taiwanese individuals and calculated the ratio of IFN-γ to IL-10 production after each individual's PBMCs were stimulated by six probiotic strains (L. paracasei BRAP01, L. acidophilus AD300, B. longum BA100, E. faecium BR0085, L. rhamnosus AD500 and L. reuteri BR101). Our results indicated that gender and age have only minor effects on the immune modulation of probiotics. Additionally, we showed that L. paracasei BRAP01 and L. acidophilus AD300 are the two dominant strains inducing IFN-γ/IL-10 production in Taiwanese individuals and that L. reuteri BR101 was the most effective stimulator of IL-10/IFN-γ. Additionally, a significant inverse relationship between the ability of L. paracasei BRAP01 and L. rhamnosus AD500 to stimulate IFN-γ/IL-10 or IL-10/IFN-γ production was also observed.

CONCLUSIONS

Our results indicated that age and gender have only minor effects on the immune modulation abilities of probiotics.

Microbes, Immunity, and Behavior: Psychoneuroimmunology Meets the Microbiome

There is now a large volume of evidence to support the view that the immune system is a key communication pathway between the gut and brain, which plays an important role in stress-related psychopathologies and thus provides a potentially fruitful target for psychotropic intervention. The gut microbiota is a complex ecosystem with a diverse range of organisms and a sophisticated genomic structure. Bacteria within the gut are estimated to weigh in excess of 1 kg in the adult human and the microbes within not only produce antimicrobial peptides, short chain fatty acids, and vitamins, but also most of the common neurotransmitters found in the human brain. That the microbial content of the gut plays a key role in immune development is now beyond doubt. Early disruption of the host-microbe interplay can have lifelong consequences, not just in terms of intestinal function but in distal organs including the brain. It is clear that the immune system and nervous system are in continuous communication in order to maintain a state of homeostasis. Significant gaps in knowledge remain about the effect of the gut microbiota in coordinating the immune-nervous systems dialogue. However, studies using germ-free animals, infective models, prebiotics, probiotics, and antibiotics have increased our understanding of the interplay. Early life stress can have a lifelong impact on the microbial content of the intestine and permanently alter immune functioning. That early life stress can also impact adult psychopathology has long been appreciated in psychiatry. The challenge now is to fully decipher the molecular mechanisms that link the gut microbiota, immune, and central nervous systems in a network of communication that impacts behavior patterns and psychopathology, to eventually translate these findings to the human situation both in health and disease. Even at this juncture, there is evidence to pinpoint key sites of communication where gut microbial interventions either with drugs or diet or perhaps fecal microbiota transplantation may positively impact mental health.

The influence of gut-derived CD39 regulatory T cells in CNS demyelinating disease

There is considerable interest in trying to understand the importance of the gut microbiome in human diseases. The association between dysbiosis, an altered microbial composition, as related to human disease is being explored in the context of different autoimmune conditions, including multiple sclerosis (MS). Recent studies suggest that MS affects the composition of the gut microbiota by altering the relative abundances of specific bacteria and archaea species. Remarkably, some of the bacterial species shown reduced in the gut of MS patients are known to promote immunosuppressive regulatory T cells (Tregs). In MS, the function of a phenotype of Tregs that express CD39, an ectoenzyme involved in the catabolism of adenosine triphosphate as immunomodulatory cells, appears to be reduced. In this review, we discuss the involvement of the gut microbiota in the regulation of experimental models of central nervous system inflammatory demyelination and review the evidence that link the gut microbiome with MS. Further, we hypothesize that the gut microbiome is an essential organ for the control of tolerance in MS patients and a potential source for safer novel therapeutics.

May the Force Be With You: The Light and Dark Sides of the Microbiota-Gut-Brain Axis in Neuropsychiatry

The role of the gut microbiota in health and disease is becoming increasingly recognized. The microbiota-gut-brain axis is a bi-directional pathway between the brain and the gastrointestinal system. The bacterial commensals in our gut can signal to the brain through a variety of mechanisms, which are slowly being resolved. These include the vagus nerve, immune mediators and microbial metabolites, which influence central processes such as neurotransmission and behaviour. Dysregulation in the composition of the gut microbiota has been identified in several neuropsychiatric disorders, such as autism, schizophrenia and depression. Moreover, preclinical studies suggest that they may be the driving force behind the behavioural abnormalities observed in these conditions. Understanding how bacterial commensals are involved in regulating brain function may lead to novel strategies for development of microbiota-based therapies for these neuropsychiatric disorders.

Microbiota and neurologic diseases: potential effects of probiotics

Background

The microbiota colonizing the gastrointestinal tract have been associated with both gastrointestinal and extra-gastrointestinal diseases. In recent years, considerable interest has been devoted to their role in the development of neurologic diseases, as many studies have described bidirectional communication between the central nervous system and the gut, the so-called “microbiota-gut-brain axis”. Considering the ability of probiotics (i.e., live non-pathogenic microorganisms) to restore the normal microbial population and produce benefits for the host, their potential effects have been investigated in the context of neurologic diseases. The main aims of this review are to analyse the relationship between the gut microbiota and brain disorders and to evaluate the current evidence for the use of probiotics in the treatment and prevention of neurologic conditions.

Discussion

Overall, trials involving animal models and adults have reported encouraging results, suggesting that the administration of probiotic strains may exert some prophylactic and therapeutic effects in a wide range of neurologic conditions. Studies involving children have mainly focused on autism spectrum disorder and have shown that probiotics seem to improve neuro behavioural symptoms. However, the available data are incomplete and far from conclusive.

Conclusions

The potential usefulness of probiotics in preventing or treating neurologic diseases is becoming a topic of great interest. However, deeper studies are needed to understand which formulation, dosage and timing might represent the optimal regimen for each specific neurologic disease and what populations can benefit. Moreover, future trials should also consider the tolerability and safety of probiotics in patients with neurologic diseases.

Gut dysbiosis impairs recovery after spinal cord injury

Kigerl et al. show that spinal cord injury causes profound changes in gut microbiota and that these changes in gut ecology are associated with activation of GALT immune cells. They show that feeding mice probiotics after SCI confers neuroprotection and improves functional recovery.

The trillions of microbes that exist in the gastrointestinal tract have emerged as pivotal regulators of mammalian development and physiology. Disruption of this gut microbiome, a process known as dysbiosis, causes or exacerbates various diseases, but whether gut dysbiosis affects recovery of neurological function or lesion pathology after traumatic spinal cord injury (SCI) is unknown. Data in this study show that SCI increases intestinal permeability and bacterial translocation from the gut. These changes are associated with immune cell activation in gut-associated lymphoid tissues (GALTs) and significant changes in the composition of both major and minor gut bacterial taxa. Postinjury changes in gut microbiota persist for at least one month and predict the magnitude of locomotor impairment. Experimental induction of gut dysbiosis in naive mice before SCI (e.g., via oral delivery of broad-spectrum antibiotics) exacerbates neurological impairment and spinal cord pathology after SCI. Conversely, feeding SCI mice commercial probiotics (VSL#3) enriched with lactic acid–producing bacteria triggers a protective immune response in GALTs and confers neuroprotection with improved locomotor recovery. Our data reveal a previously unknown role for the gut microbiota in influencing recovery of neurological function and neuropathology after SCI.

Induction of gut regulatory CD39+ T cells by teriflunomide protects against EAE

Objective:

To determine whether as an orally delivered treatment, teriflunomide, an inhibitor of the mitochondrial enzyme dihydroorotate dehydrogenase approved to treat relapsing forms of multiple sclerosis, could affect gut-associated lymphoid tissue (GALT) immune responses functionally.

Methods:

C57BL/6 mice were treated orally with teriflunomide and flow cytometric analysis of immune GALT cells performed ex vivo, and adoptive transfer experiments were used to test the protective effects of GALT regulatory T (Treg) cells.

Results:

Teriflunomide reduced the percentages of antigen-presenting cells of Peyer patches when compared to controls. Conversely, a significant increase of the relative frequency of CD39⁺ Treg cells was observed. In vivo, the protective effect of GALT-derived teriflunomide-induced CD39⁺ Treg cells was established by adoptive transfer into recipient experimental autoimmune encephalomyelitis mice.

Conclusions:

Our results identify specific GALT-derived CD39⁺ Treg cells as a mechanism of action that may contribute to the efficacy of teriflunomide during CNS inflammatory demyelination and as an oral therapeutic in relapsing multiple sclerosis.

Enterococcus faecium strain L-3 and glatiramer acetate ameliorate experimental allergic encephalomyelitis in rats by affecting different populations of immune cells

The effect of probiotic Enterococcus faecium strain L-3 was studied in rats with experimental allergic encephalomyelitis (EAE). Glatiramer acetate (GA) was used as control drug. E. faecium strain L-3 and GA both were able to reduce the severity of EAE in a similar fashion. Both approaches increased the proportion of EAE resistant rats and rats with mild disease, prolonged the inductive phase of EAE and reduced the disease duration. Study of the phenotypes of immune cells in blood revealed the differences in immunoregulatory pathways that mediate the protective action of probiotic or GA treatment of EAE. The presence of pronounced protective and immunomodulating effects of the probiotic E. faecium strain L-3 opens an opportunity of its application for the treatment of multiple sclerosis.

The effect of a probiotic Escherichia coli strain on regulatory T-cells in six year-old children

Probiotics are believed to prevent or reduce allergy development but the mechanism of their beneficial effect is still poorly understood. Immune characteristics of regulatory T cells (Tregs) in peripheral blood of perinatally probiotic-supplemented children of allergic mothers (51 children), non-supplemented children of allergic mothers (42 children), and non-supplemented children of healthy mothers (28 children) were compared at the age of 6-7 years. A first dose of a probiotic Escherichia coli strain (E. coli O83:K24:H31) was administered within 2 days after the birth and then 12 times during the first months of life and children were followed longitudinally. Proportion and functional properties of Tregs were estimated by flow cytometry in relation to the children's allergy status. Proportion of Tregs in the peripheral blood of children suffering from allergy tends to be higher whereas median of fluorescence intensity (MFI) of FoxP3 was significantly decreased in allergic group. Intracellular presence of regulatory cytokine interleukin (IL)-10 was also lower in allergic children. Immune functions of Tregs reflected by both MFI of FoxP3 and IL-10 in the group of probiotic-supplemented children of allergic mothers were nearly comparable with children of healthy mothers while probiotic non-supplemented children of allergic mothers have decreased immune function of Tregs. Supplementation by probiotic E. coli strain decreases allergy incidence in high-risk children. In contrast to our expectation, proportion of Tregs has not been increased in probiotic supplemented children. Beneficial effect of probiotics on newborn immature immune system could be, at least partially, explained by the modulating immune function of Tregs. In summary, we detected increased proportion of Tregs in peripheral blood of allergic children, their functional properties were decreased in comparison with the Tregs of healthy children. A unifying hypothesis for these findings is that Treg numbers in allergic children are increased in order to compensate for decreased function.

Treatment with NAD(+) inhibited experimental autoimmune encephalomyelitis by activating AMPK/SIRT1 signaling pathway and modulating Th1/Th17 immune responses in mice

Nicotinamide adenine dinucleotide (NAD(+)) plays vital roles in mitochondrial functions, cellular energy metabolism and calcium homeostasis. In this study, we investigated the effect of NAD(+) administration for the treatment of experimental autoimmune encephalomyelitis (EAE) in C57BL/6 mice. EAE, a classical animal model of multiple sclerosis (MS), was induced by subcutaneous injection of myelin oligodendrocyteglycoprotein (MOG). The mice were treated with 250mg/kg (body weight) NAD(+) in PBS administered intraperitoneally once daily. We observed that NAD(+) treatment could lessen the severity of EAE. Additionally, NAD(+) treatment attenuated pathological injuries of EAE mice. We also found that the AMP-activated protein kinase (AMPK)/silent mating-type information regulation 2 homolog 1(SIRT1) pathway was activated in the NAD(+)-treated mice and NAD(+) treatment suppressed pro-inflammatory T cell responses. Our findings demonstrated that NAD(+) could be an effective and promising agent to treat multiple sclerosis and its effects on other autoimmune diseases should be explored.

The Gut Microbiota in Immune-Mediated Inflammatory Diseases

The collection of microbes and their genes that exist within and on the human body, collectively known as the microbiome has emerged as a principal factor in human health and disease. Humans and microbes have established a symbiotic association over time, and perturbations in this association have been linked to several immune-mediated inflammatory diseases (IMID) including inflammatory bowel disease, rheumatoid arthritis, and multiple sclerosis. IMID is a term used to describe a group of chronic, highly disabling diseases that affect different organ systems. Though a cornerstone commonality between IMID is the idiopathic nature of disease, a considerable portion of their pathobiology overlaps including epidemiological co-occurrence, genetic susceptibility loci and environmental risk factors. At present, it is clear that persons with an IMID are at an increased risk for developing comorbidities, including additional IMID. Advancements in sequencing technologies and a parallel explosion of 16S rDNA and metagenomics community profiling studies have allowed for the characterization of microbiomes throughout the human body including the gut, in a myriad of human diseases and in health. The main challenge now is to determine if alterations of gut flora are common between IMID or, if particular changes in the gut community are in fact specific to a single disease. Herein, we review and discuss the relationships between the gut microbiota and IMID.

Further understanding of the immunopathology of multiple sclerosis: impact on future treatments

INTRODUCTION

The understanding of the immunopathogenesis of multiple sclerosis (MS) has expanded with more research into T-cell subtypes, cytokine contributors, B-cell participation, mitochondrial dysfunction, and more. Treatment options have rapidly expanded with three relatively recent oral therapy alternatives entering the arena.

AREAS COVERED

In the following review, we discuss current mechanisms of immune dysregulation in MS, how they relate to current treatments, and the impact these findings will have on the future of therapy. Expert commentary: The efficacy of these medications and understanding their mechanisms of actions validates the immunopathogenic mechanisms thought to underlie MS. Further research has exposed new targets, while new promising therapies have shed light on new aspects into the pathophysiology of MS.

Development and maintenance of intestinal regulatory T cells

Gut-resident forkhead box P3 (FOXP3)(+)CD4(+) regulatory T cells (Treg cells) are distinct from those in other organs and have gut-specific phenotypes and functions. Whereas Treg cells in other organs have T cell receptors (TCRs) specific for self antigens, intestinal Treg cells have a distinct set of TCRs that are specific for intestinal antigens, and these cells have pivotal roles in the suppression of immune responses against harmless dietary antigens and commensal microorganisms. The differentiation, migration and maintenance of intestinal Treg cells are controlled by specific signals from the local environment. In particular, certain members of the microbiota continuously provide antigens and immunoregulatory small molecules that modulate intestinal Treg cells. Understanding the development and the maintenance of intestinal Treg cells provides important insights into disease-relevant host-microorganism interactions.

Lactobacillus reuteri 6475 Increases Bone Density in Intact Females Only under an Inflammatory Setting

BACKGROUND & AIMS

We previously demonstrated that short-term oral administration of the probiotic Lactobacillus reuteri 6475 enhanced bone density in male but not female mice. We also established that L. reuteri 6475 enhanced bone health and prevented bone loss in estrogen-deficient female mice. In this study, we tested whether a mild inflammatory state and/or a long-term treatment with the probiotic was required to promote a positive bone effect in estrogen-sufficient female mice.

METHODS

A mild inflammatory state was induced in female mice by dorsal surgical incision (DSI). Following DSI animals were orally supplemented with L. reuteri or vehicle control for a period of 8 weeks. Gene expression was measured in the intestine and bone marrow by qPCR. Distal femoral bone density and architecture was analyzed by micro-CT.

RESULTS

We report that 8 weeks after DSI there is a significant increase in the weight of spleen, thymus and visceral (retroperitoneal) fat pads. Expression of intestinal cytokines and tight junction proteins are also altered 8 weeks post-DSI. Interestingly, L. reuteri treatment was found to display both intestinal region- and inflammation-dependent effects. Unexpectedly we identified that 1) L. reuteri treatment increased bone density in females but only in those that underwent DSI and 2) DSI benefited cortical bone parameters. In the bone marrow, dorsal surgery induced CD4+ T cell numbers, a response that was unaffected by L. reuteri treatment, whereas expression of RANKL, OPG and IL-10 were significantly affected by L. reuteri treatment.

CONCLUSION

Our data reveals a previously unappreciated effect of a mild surgical procedure causing a long-lasting effect on inflammatory gene expression in the gut and the bone. Additionally, we demonstrate that in intact female mice, the beneficial effect of L. reuteri on bone requires an elevated inflammatory status.

Induction of regulatory T cells: A role for probiotics and prebiotics to suppress autoimmunity

Regulatory T cells (Tregs) are comprised of a heterogeneous population of cells that play a vital role in suppressing inflammation and maintaining immune tolerance. Given the crucial role of Tregs in maintaining immune homeostasis, it is probably not surprising that many microbial species and their metabolites have the potential to induce Tregs. There is now great interest in the therapeutic potential of probiotics and prebiotics based strategies for a range of autoimmune disorders. This review will summarise recent findings concerning the role of probiotics and prebiotics in induction of Tregs to ameliorate the autoimmune conditions. In addition, the article is focused to explain the different mechanisms of Treg induction and function by these probiotics and prebiotics, based on the available studies till date. The article further proposes that induction of Tregs by probiotics and prebiotics could lead to the development of new therapeutic approach towards curbing the autoimmune response and as an alternative to detrimental immunosuppressive drugs.

The Second Brain: Is the Gut Microbiota a Link Between Obesity and Central Nervous System Disorders?

The gut-brain axis is a bi-directional integrated system composed by immune, endocrine, and neuronal components by which the gap between the gut microbiota and the brain is significantly impacted. An increasing number of different gut microbial species are now postulated to regulate brain function in health and disease. The westernized diet is hypothesized to be the cause of the current obesity levels in many countries, a major socio-economical health problem. Experimental and epidemiological evidence suggest that the gut microbiota is responsible for significant immunologic, neuronal, and endocrine changes that lead to obesity. We hypothesize that the gut microbiota, and changes associated with diet, affect the gut-brain axis and may possibly contribute to the development of mental illness. In this review, we discuss the links between diet, gut dysbiosis, obesity, and immunologic and neurologic diseases that impact brain function and behavior.

Gut microbiota, obesity and diabetes

The central role of the intestinal microbiota in the progression and, equally, prevention of metabolic dysfunction is becoming abundantly apparent. The symbiotic relationship between intestinal microbiota and host ensures appropriate development of the metabolic system in humans. However, disturbances in composition and, in turn, functionality of the intestinal microbiota can disrupt gut barrier function, a trip switch for metabolic endotoxemia. This low-grade chronic inflammation, brought about by the influx of inflammatory bacterial fragments into circulation through a malfunctioning gut barrier, has considerable knock-on effects for host adiposity and insulin resistance. Conversely, recent evidence suggests that there are certain bacterial species that may interact with host metabolism through metabolite-mediated stimulation of enteric hormones and other systems outside of the gastrointestinal tract, such as the endocannabinoid system. When the abundance of these keystone species begins to decline, we see a collapse of the symbiosis, reflected in a deterioration of host metabolic health. This review will investigate the intricate axis between the microbiota and host metabolism, while also addressing the promising and novel field of probiotics as metabolic therapies.

Advances in the immunopathogenesis of multiple sclerosis

PURPOSE OF REVIEW

Recent studies indicate a role for immune dysregulation in the pathogenesis of multiple sclerosis, an inflammatory demyelinating and degenerative disease of the central nervous system. This review addresses the current mechanisms of immune dysregulation in the development of multiple sclerosis, including the impact of environmental risk factors on immunity in both multiple sclerosis and its animal models.

RECENT FINDINGS

CD4 T-helper (Th) cells have long been implicated as the main drivers of pathogenesis of multiple sclerosis. However, current studies indicate that multiple sclerosis is largely a heterogeneous disease process, which involves both innate and adaptive immune-mediated inflammatory mechanisms that ultimately contribute to demyelination and neurodegeneration. Therefore, B cells, CD8 T cells, and microglia/macrophages can also play an important role in the immunopathogenesis of multiple sclerosis apart from proinflammatory CD4 Th1/Th17 cell subsets. Furthermore, increasing evidence indicates that environmental risk factors, such as Vitamin D deficiency, Epstein-Barr virus, smoking, Western diet, and the commensal microbiota, influence the development of multiple sclerosis through interactions with genetic variants of multiple sclerosis, thus leading to the dysregulation of immune responses.

SUMMARY

A better understanding of immune-mediated mechanisms in the pathogenesis of multiple sclerosis and the contribution of environmental risk factors toward the development of multiple sclerosis will help further improve therapeutic approaches to prevent disease progression.

PROBIOTIC APPROACHES FOR TARGETING INFLAMMATORY BOWEL DISEASE: AN UPDATE ON ADVANCES AND OPPORTUNITIES IN MANAGING THE DISEASE

Various commensal enteric and pathogenic bacteria may be involved in the pathogenesis of inflammatory bowel diseases (IBDs), a chronic condition with a pathogenic background that involves both immunogenetic and environmental factors. IBDs comprising of Crohn's disease, and ulcerative colitis, and pauchitis are chronic inflammatory conditions, and known for causing disturbed homeostatic balance among the intestinal immune compartment, gut epithelium and microbiome. An increasing trend of IBDs in incidence, prevalence, and severity has been reported during recent years. Probiotic strains have been reported to manage the IBDs and related pathologies, and hence are current hot topics of research for their potential to manage metabolic diseases as well as various immunopathologies. However, the probiotics industry will need to undergo a transformation, with increased focus on stringent manufacturing guidelines and high-quality clinical trials. This article reviews the present state of art of role of probiotic bacteria in reducing inflammation and strengthening the host immune system with reference to the management of IBDs. We infer that t healthcare will move beyond its prevailing focus on human physiology, and embrace the superorganism as a paradigm to understand and ameliorate IBDs.

Regulation of IL-10 and IL-12 production and function in macrophages and dendritic cells

Interleukin-10 and Interleukin-12 are produced primarily by pathogen-activated antigen-presenting cells, particularly macrophages and dendritic cells. IL-10 and IL-12 play very important immunoregulatory roles in host defense and immune homeostasis. Being anti- and pro-inflammatory in nature, respectively, their functions are antagonistically opposing. A comprehensive and in-depth understanding of their immunological properties and signaling mechanisms will help develop better clinical intervention strategies in therapy for a wide range of human disorders. Here, we provide an update on some emerging concepts, controversies, unanswered questions, and opinions regarding the immune signaling of IL-10 and IL-12.

TNFR2 Deficiency Acts in Concert with Gut Microbiota To Precipitate Spontaneous Sex-Biased Central Nervous System Demyelinating Autoimmune Disease

TNF-α antagonists provide benefit to patients with inflammatory autoimmune disorders such as Crohn's disease, rheumatoid arthritis, and ankylosing spondylitis. However, TNF antagonism unexplainably exacerbates CNS autoimmunity, including multiple sclerosis and neuromyelitis optica. The underlying mechanisms remain enigmatic. We demonstrate that TNFR2 deficiency results in female-biased spontaneous autoimmune CNS demyelination in myelin oligodendrocyte glycoprotein-specific 2D2 TCR transgenic mice. Disease in TNFR2(-/-) 2D2 mice was associated with CNS infiltration of T and B cells as well as increased production of myelin oligodendrocyte glycoprotein-specific IL-17, IFN-γ, and IgG2b. Attenuated disease in TNF(-/-) 2D2 mice relative to TNFR2(-/-) 2D2 mice identified distinctive roles for TNFR1 and TNFR2. Oral antibiotic treatment eliminated spontaneous autoimmunity in TNFR2(-/-) 2D2 mice to suggest role for gut microbiota. Illumina sequencing of fecal 16S rRNA identified a distinct microbiota profile in male TNFR2(-/-) 2D2 that was associated with disease protection. Akkermansia muciniphila, Sutterella sp., Oscillospira sp., Bacteroides acidifaciens, and Anaeroplasma sp. were selectively more abundant in male TNFR2(-/-) 2D2 mice. In contrast, Bacteroides sp., Bacteroides uniformis, and Parabacteroides sp. were more abundant in affected female TNFR2(-/-) 2D2 mice, suggesting a role in disease causation. Overall, TNFR2 blockade appears to disrupt commensal bacteria-host immune symbiosis to reveal autoimmune demyelination in genetically susceptible mice. Under this paradigm, microbes likely contribute to an individual's response to anti-TNF therapy. This model provides a foundation for host immune-microbiota-directed measures for the prevention and treatment of CNS-demyelinating autoimmune disorders.

Implications of dietary salt intake for multiple sclerosis pathogenesis

In recent years it has become increasingly clear that, alongside genetic risk factors, environmental factors strongly influence the incidence and severity of multiple sclerosis (MS). Based on observations from epidemiological studies, the potential contribution of dietary habits has lately been a matter of debate. Recently it was shown that high salt conditions promote pathogenic T-cell responses and aggravate autoimmunity in an animal model of MS, suggesting that high dietary salt intake might promote central nervous system (CNS) autoimmunity. However, so far, not much is known about the influence of dietary salt intake on MS disease pathology. Here, we discuss the association of dietary salt levels and MS with a special focus on the mechanisms of salt-mediated modulation of the different cell types critically involved in the pathophysiology of MS.

Role of intestinal microbiota in the development of multiple sclerosis

INTRODUCTION

Multiple sclerosis (MS) is a demyelinating disease that affects young adults; in that age group, it represents the second leading cause of disability in our setting. Its precise aetiology has not been elucidated, but it is widely accepted to occur in genetically predisposed patients who are exposed to certain environmental factors. The discovery of the regulatory role played by intestinal microbiota in various autoimmune diseases has opened a new line of research in this field, which is discussed in this review.

DEVELOPMENT

We reviewed published studies on the role of the microbiota in the development of both MS and its animal model, experimental autoimmune encephalomyelitis (EAE). In mice, it has been shown that intestinal microorganisms regulate the polarisation of T helper cells from Th1-Th17 up to Th2, the function of regulatory T cells, and the activity of B cells; they participate in the pathogenesis of EAE and contribute to its prevention and treatment. In contrast, evidence in humans is still scarce and mainly based on case-control studies that point to the presence of differences in certain bacterial communities.

CONCLUSIONS

Multiple evidence points to the role of microbiota in EAE. Extrapolation of these results to MS is still in the early stages of research, and studies are needed to define which bacterial populations are associated with MS, the role they play in pathogenesis, and the therapeutic possibilities this knowledge offers us.

Modulation of immunity and gut microbiota after dietary administration of alginate encapsulated Shewanella putrefaciens Pdp11 to gilthead seabream (Sparus aurata L.)

The potential benefits of probiotics when administering to fish could improve aquaculture production. The objective of this study was to examine the modulation of immune status and gut microbiota of gilthead seabream (Sparus aurata L.) specimens by a probiotic when administered encapsulated. Commercial diet was enriched with Shewanella putrefaciens Pdp11 (SpPdp11, at a concentration of 10(8) cfu g(-1)) before being encapsulated in calcium alginate beads. Fish were fed non-supplemented (control) or supplemented diet for 4 weeks. After 1, 2 and 4 weeks the main humoral and cellular immune parameters were determined. Furthermore, gene expression profile of five immune relevant genes (il1β, bd, mhcIIα, ighm and tcrβ) was studied by qPCR in head kidney. On the other hand, intestinal microbiota of fish was analysed at 7 and 30 days by DGGE. Results demonstrated that administration of alginate encapsulated SpPdp11 has immunostimulant properties on humoral parameters (IgM level and serum peroxidase activity). Although no immunostimulant effects were detected on leucocyte activities, significant increases were detected in the level of mRNA of head-kidney leucocytes for mhcIIα and tcrβ after 4 weeks of feeding the encapsulated-probiotic diet. The administration of SpPdp11 encapsulated in alginate beads produced important changes in the DGGE patterns corresponding to the intestinal microbiota. Predominant bands related to lactic acid bacteria, such as Lactococcus and Lactobacillus strains, were sequenced from the DGGE patterns of fish fed the probiotic diet, whereas they were not sequenced from fish receiving the control diet. The convenience or not of probiotic encapsulation is discussed.

Antibiotics in early life alter the gut microbiome and increase disease incidence in a spontaneous mouse model of autoimmune insulin-dependent diabetes

Insulin-dependent or type 1 diabetes is a prototypic autoimmune disease whose incidence steadily increased over the past decades in industrialized countries. Recent evidence suggests the importance of the gut microbiota to explain this trend. Here, non-obese diabetic (NOD) mice that spontaneously develop autoimmune type 1 diabetes were treated with different antibiotics to explore the influence of a targeted intestinal dysbiosis in the progression of the disease. A mixture of wide spectrum antibiotics (i.e. streptomycin, colistin and ampicillin) or vancomycin alone were administered orally from the moment of conception, treating breeding pairs, and during the postnatal and adult life until the end of follow-up at 40 weeks. Diabetes incidence significantly and similarly increased in male mice following treatment with these two antibiotic regimens. In NOD females a slight yet not significant trend towards an increase in disease incidence was observed. Changes in gut microbiota composition were assessed by sequencing the V3 region of bacterial 16S rRNA genes. Administration of the antibiotic mixture resulted in near complete ablation of the gut microbiota. Vancomycin treatment led to increased Escherichia, Lactobacillus and Sutterella genera and decreased members of the Clostridiales order and Lachnospiraceae, Prevotellaceae and Rikenellaceae families, as compared to control mice. Massive elimination of IL-17-producing cells, both CD4+TCRαβ+ and TCRγδ+ T cells was observed in the lamina propria of the ileum and the colon of vancomycin-treated mice. These results show that a directed even partial ablation of the gut microbiota, as induced by vancomycin, significantly increases type 1 diabetes incidence in male NOD mice thus prompting for caution in the use of antibiotics in pregnant women and newborns.

Gut commensalism, cytokines, and central nervous system demyelination

There is increasing support for the importance of risk factors such as genetic makeup, obesity, smoking, vitamin D insufficiency, and antibiotic exposure contributing to the development of autoimmune diseases, including human multiple sclerosis (MS). Perhaps the greatest environmental risk factor associated with the development of immune-mediated conditions is the gut microbiome. Microbial and helminthic agents are active participants in shaping the immune systems of their hosts. This concept is continually reinforced by studies in the burgeoning area of commensal-mediated immunomodulation. The clinical importance of these findings for MS is suggested by both their participation in disease and, perhaps of greater clinical importance, attenuation of disease severity. Observations made in murine models of central nervous system demyelinating disease and a limited number of small studies in human MS suggest that immune homeostasis within the gut microbiome may be of paramount importance in maintaining a disease-free state. This review describes three immunological factors associated with the gut microbiome that are central to cytokine network activities in MS pathogenesis: T helper cell polarization, T regulatory cell function, and B cell activity. Comparisons are drawn between the regulatory mechanisms attributed to first-line therapies and those described in commensal-mediated amelioration of central nervous system demyelination.

The gut microbiome in multiple sclerosis

OPINION STATEMENT

The gut microbiome is made up of a wide range of (chiefly) bacterial species that colonize the small and large intestine. The human gut microbiome contains a subset of thousands of bacterial species, with up to 10(14) total bacteria. Studies examining this bacterial content have shown wide variations in which species are present between individuals. The gut microbiome has been shown to have profound effects on the development and maintenance of immune system in both animal models and in humans. A growing body of evidence has implicated the human gut microbiome in a range of disorders, including obesity, inflammatory bowel diseases, and cardiovascular disease. Animal studies present compelling evidence that the gut microbiome plays a significant role in the progression of demyelinating disease, and that modulation of the microbiome can lead to either exacerbation or amelioration of symptoms. Differences in diet, vitamin D insufficiency, smoking, and alcohol use have all been implicated as risk factors in MS, and all have the ability to affect the composition of the gut microbiota. Preliminary clinical trials aimed at modulating the gut microbiota in MS patients are underway and may prove to be a promising and lower-risk treatment option in the future.

Intestinal microbiota as modulators of the immune system and neuroimmune system: impact on the host health and homeostasis

Many immune-based intestinal disorders, such as ulcerative colitis and Crohn's disease, as well as other illnesses, may have the intestines as an initial cause or aggravator in the development of diseases, even apparently not correlating directly to the intestine. Diabetes, obesity, multiple sclerosis, depression, and anxiety are examples of other illnesses discussed in the literature. In parallel, importance of the gut microbiota in intestinal homeostasis and immunologic conflict between tolerance towards commensal microorganisms and combat of pathogens is well known. Recent researches show that the immune system, when altered by the gut microbiota, influences the state in which these diseases are presented in the patient directly and indirectly. At the present moment, a considerable number of investigations about this subject have been performed and published. However, due to difficulties on correlating information, several speculations and hypotheses are generated. Thus, the present review aims at bringing together how these interactions work-gut microbiota, immune system, and their influence in the neuroimmune system.

Effects of the gut microbiota on bone mass

The gut microbiota (GM), the commensal bacteria living in our intestine, performs numerous useful functions, including modulating host metabolism and immune status. Recent studies demonstrate that the GM is also a regulator of bone mass and it is proposed that the effect of the GM on bone mass is mediated via effects on the immune system, which in turn regulates osteoclastogenesis. Under normal conditions, the skeleton is constantly remodeled by bone-forming osteoblasts (OBs) and bone-resorbing osteoclasts (OCLs), and imbalances in this process may lead to osteoporosis. Here we review current knowledge on the possible role for the GM in the regulation of bone metabolism and propose that the GM might be a novel therapeutic target for osteoporosis and fracture prevention.

Regulatory T cells in vitiligo: Implications for pathogenesis and therapeutics

Vitiligo is a hypomelanotic autoimmune skin disease arising from a breakdown in immunological self-tolerance, which leads to aberrant immune responses against melanocytes. Regulatory T cells (Tregs) are crucial to the development of self-tolerance and so are major foci in the study of autoimmune pathogenesis of vitiligo. This review will summarise recent findings concerning the role of Tregs in the pathogenesis of vitiligo. In addition, as antigen-specific Tregs are a potential route for the reinstatement of immune tolerance, new strategies that expand or induce de novo generation of Tregs and which are currently being investigated as therapies for other autoimmune diseases, will be discussed. These approaches will highlight the opportunities for Treg cell-based therapeutics in vitiligo.

The effects of combined dietary probiotics Lactococcus lactis BFE920 and Lactobacillus plantarum FGL0001 on innate immunity and disease resistance in olive flounder (Paralichthys olivaceus)

The effects of a dietary probiotic mixture containing Lactococcus (Lc.) lactis BFE920 isolated from bean sprout and autochthonous Lactobacillus (Lb.) plantarum FGL0001 originally isolated from the hindgut of olive flounder (Paralichthys olivaceus) were investigated for the purpose of improving the probiotic effects of Lc. lactis BFE920 on the olive flounder. The immunostimulatory, disease protective, and weight gain effects of Lc. lactis BFE920 were significantly improved when olive flounder (average weight 37.5±1.26 g) were fed the probiotic mixture (log10 7.0 CFU each/g feed pellet) for 30 days. Flounder fed the mixture showed improved skin mucus lysozyme activity and phagocytic activity of innate immune cells compared to flounder fed a single probiotic agent or a control diet. While the levels of neutrophil activity in flounder fed the single probiotic agent or the mixture were similar, they were significantly higher than levels in a control group. Additionally, probiotic-fed flounder showed significantly increased expressions of IL-6, IL-8, and TNF-α in the intestine compared to the control group. Following a 30-day period of being fed probiotics or a control diet, the olive flounder were challenged with an i.p. injection of Streptococcus iniae (log10 6.0 CFU/fish). The groups fed the mixed probiotics, Lc. lactis BFE920, Lb. plantarum FGL0001, and the control diet had survival rates of 55%, 45%, 35%, and 20%, respectively. Flounder fed the probiotic mixture gained 38.1±2.8% more body weight compared to flounder fed the control diet during the 30-day study period. These data strongly suggest that a mixture of Lc. lactis BFE920 and Lb. plantarum FGL0001 may serve as an immunostimulating feed additive useful for disease protection in the fish farming industry.

Dietary Yeasts Reduce Inflammation in Central Nerve System via Microflora

Objectives

The intestinal microflora affects the pathogenesis of several autoimmune diseases by influencing immune system function. Some bacteria, such as lactic acid bacteria, have been reported to have beneficial effects on immune function. However, little is known about the effects of yeasts. Here, we aimed to investigate the effects of various dietary yeasts contained in fermented foods on experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS), and to elucidate the mechanisms underlying these effects.

Methods

The effects of eight yeasts selected from 18 types of yeasts contained in fermented foods were examined using an EAE model. Of these, Candida kefyr was investigated by analyzing the intestinal microflora and its effects on intestinal and systemic immune states.

Results

Administration of C. kefyr ameliorated the severity of EAE. Reduced numbers of Th17 cells, suppressed interleukin (IL)-6 production by intestinal explants, and increased Tregs and CD103-positive regulatory dendritic cells in mesenteric lymph nodes (MLNs) were observed. Analysis of 16s-rDNA from feces of C. kefyr-treated mice demonstrated increased Lactobacillales and decreased Bacteroides compared to control flora. Transfer of intestinal microbiota also resulted in decreased Bacteroides and ameliorated symptoms of EAE. Thus, oral administration of C. kefyr ameliorated EAE by altering the microflora, accompanied by increased Tregs and CD103-positive regulatory dendritic cells in MLNs and decreased Th17 cells in the intestinal lamina propria.

Interpretation

Oral ingestion of C. kefyr may have beneficial effects on MS by modifying microflora. In addition, our findings also suggested the potential health benefits of dietary yeasts.

Gut microbiome and the risk factors in central nervous system autoimmunity

Humans are colonized after birth by microbial organisms that form a heterogeneous community, collectively termed microbiota. The genomic pool of this macro-community is named microbiome. The gut microbiota is essential for the complete development of the immune system, representing a binary network in which the microbiota interact with the host providing important immune and physiologic function and conversely the bacteria protect themselves from host immune defense. Alterations in the balance of the gut microbiome due to a combination of environmental and genetic factors can now be associated with detrimental or protective effects in experimental autoimmune diseases. These gut microbiome alterations can unbalance the gastrointestinal immune responses and influence distal effector sites leading to CNS disease including both demyelination and affective disorders. The current range of risk factors for MS includes genetic makeup and environmental elements. Of interest to this review is the consistency between this range of MS risk factors and the gut microbiome. We postulate that the gut microbiome serves as the niche where different MS risk factors merge, thereby influencing the disease process.

The effect of omeprazole on the development of experimental autoimmune encephalomyelitis in C57BL/6J and SJL/J mice

BACKGROUND

Gastric disturbances such as dyspepsia are routinely encountered by multiple sclerosis (MS) patients, and these conditions are often treated with gastric acid suppressors such as proton pump inhibitors, histamine H2 receptor antagonists, or antacids. The proton pump inhibitor omeprazole can alter the gut flora and immune responses, both of which can influence the course of experimental autoimmune encephalomyelitis (EAE), an animal model of MS. The objective of the current study was to examine the effect of omeprazole treatment on the development of EAE. Bacterial microbiome analysis of mouse fecal pellets was determined in C57BL/6J EAE mice chronically treated with omeprazole, and spleen immune cell content, clinical scores, weight, rotarod latency, and histopathology were used as outcome measures in C57BL/6J and SJL/J mice with EAE.

RESULTS

Omeprazole treatment resulted in decreases in Akkermansia muciniphila and Coprococcus sp. and an increase in unidentified bacteria in the family S24-7 (order Bacteroidales) in C57BL/6J mice with EAE. Omeprazole did not alter spleen immune cell content compared to vehicle in EAE mice, but differences independent of treatment were observed in subsets of T cells between early and advanced disease in C57BL/6J mice as well as between the two strains of mice at an advanced disease stage. Omeprazole caused no difference in clinical scores in either strain, but significantly lowered weight gain compared to vehicle in the C57BL/6J mice with EAE. Omeprazole also did not alter rotarod behavior or hindbrain inflammatory cell infiltration compared to vehicle in both strains of mice with EAE. Rotarod latency did reveal a negative correlation with clinical scores during active disease in both mouse strains, but not during clinical remission in SJL/J mice, suggesting that rotarod can detect disability not reflected in the clinical scores.

CONCLUSIONS

Despite alterations in the gut microbiota and weight gain in the C57BL/6J EAE model, omeprazole had no effect on multiple measures of disease activity in C57BL/6J and SJL/J mice with EAE, supporting the notion that omeprazole does not substantially influence disease activity in MS patients.

Intestinal barrier dysfunction develops at the onset of experimental autoimmune encephalomyelitis, and can be induced by adoptive transfer of auto-reactive T cells

Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system with a pathogenesis involving a dysfunctional blood-brain barrier and myelin-specific, autoreactive T cells. Although the commensal microbiota seems to affect its pathogenesis, regulation of the interactions between luminal antigens and mucosal immune elements remains unclear. Herein, we investigated whether the intestinal mucosal barrier is also targeted in this disease. Experimental autoimmune encephalomyelitis (EAE), the prototypic animal model of MS, was induced either by active immunization or by adoptive transfer of autoreactive T cells isolated from these mice. We show increased intestinal permeability, overexpression of the tight junction protein zonulin and alterations in intestinal morphology (increased crypt depth and thickness of the submucosa and muscularis layers). These intestinal manifestations were seen at 7 days (i.e., preceding the onset of neurological symptoms) and at 14 days (i.e., at the stage of paralysis) after immunization. We also demonstrate an increased infiltration of proinflammatory Th1/Th17 cells and a reduced regulatory T cell number in the gut lamina propria, Peyer's patches and mesenteric lymph nodes. Adoptive transfer to healthy mice of encephalitogenic T cells, isolated from EAE-diseased animals, led to intestinal changes similar to those resulting from the immunization procedure. Our findings show that disruption of intestinal homeostasis is an early and immune-mediated event in EAE. We propose that this intestinal dysfunction may act to support disease progression, and thus represent a potential therapeutic target in MS. In particular, an increased understanding of the regulation of tight junctions at the blood-brain barrier and in the intestinal wall may be crucial for design of future innovative therapies.