Melatonin and vitamin D, two sides of the same coin, better to land on its edge to improve multiple sclerosis.

Previous studies revealed a latitudinal gradient of multiple sclerosis (MS) prevalence, increasing by moving from the equator to the poles. The duration and quality of an individual's exposure to sunlight vary with latitude. Skin exposure to sunlight activates vitamin D synthesis, while light absence, as perceived by the eyes, activates melatonin synthesis in the pineal gland. Vitamin D or melatonin deficiency/insufficiency or overdose can occur at any latitude due to specific lifestyles and diets. Moving away from the equator, especially beyond 37°, decreases vitamin D while raising melatonin. Furthermore, melatonin synthesis increases in cold habitats like northern countries. Since melatonin's beneficial role was shown in MS, it is expected that northern countries whose individuals have higher endogenous melatonin should show a lower MS prevalence; however, these are ranked with the highest scores. In addition, countries like the United States and Canada have uncontrolled over-the-counter usage. In high latitudes, vitamin D deficiency and a higher MS prevalence persist even though vitamin D is typically compensated for by supplementation and not sunlight. Recently, we found that prolonged darkness increased MS melatonin levels, mimicking the long-term increase in northern countries. This caused a reduction in cortisol and increased infiltration, inflammation, and demyelination, which were all rescued by constant light therapy. In this review, we explain melatonin and vitamin D's possible roles in MS prevalence. The possible causes in northern countries are then discussed. Finally, we suggest strategies to treat MS by manipulating vitamin D and melatonin, preferably with sunlight or darkness, not supplements.

Inhibiting nighttime melatonin and boosting cortisol increase patrolling monocytes, phagocytosis, and myelination in a murine model of multiple sclerosis.

Conflicting results on melatonin synthesis in multiple sclerosis (MS) have been reported due to variabilities in patient lifestyles, which are not considered when supplementing melatonin. Since melatonin acts through its receptors, we identified melatonin receptors in oligodendrocytes (OLs) in the corpus callosum, where demyelination occurs; the subventricular zone, where neural stem/progenitor cells (NSPCs) are located; and the choroid plexus, which functions as a blood-cerebrospinal fluid barrier. Moreover, using chimeric mice, resident macrophages were found to express melatonin receptors, whereas bone marrow-derived macrophages lost this expression in the demyelinated brain. Next, we showed that cuprizone-fed mice, which is an MS model, tended to have increased melatonin levels. While we used different approaches to alter the circadian rhythm of melatonin and cortisol, only the constant light approach increased NSPC proliferation and differentiation to oligodendrocyte precursor cells (OPCs), OPCs maturation to OLs and recruitment to the site of demyelination, the number of patrolling monocytes, and phagocytosis. In contrast, constant darkness and exogenous melatonin exacerbated these events and amplified monocyte infiltration. Therefore, melatonin should not be considered a universal remedy, as is currently claimed. Our data emphasize the importance of monitoring melatonin/cortisol oscillations in each MS patient by considering diet and lifestyle to avoid melatonin overdose.

A founder mutation in the PLPBP gene in families from Saguenay-Lac-St-Jean region affected by a pyridoxine-dependent epilepsy.

Pyridoxine-dependent epilepsy (PDE) is a relatively rare subgroup of epileptic disorders. They generally present in infancy as an early onset epileptic encephalopathy or seizures, refractory to standard treatments, with rapid and variable responses to vitamin B6 treatment. Whole exome sequencing of three unrelated families identified homozygous pathogenic mutation c.370_373del, p.Asp124fs in PLPBP gene in five persons. Haplotype analysis showed a single shared profile for the affected persons and their parents, leading to a hypothesis about founder effect of the mutation in Saguenay-Lac-St-Jean region of French Canadians. All affected probands also shared one single mitochondrial haplotype T2b3 and two rare variations in the mitochondrial genome m.801A>G and m.5166A>G suggesting that a single individual female introduced PLPBP mutation c.370_373del, p.Asp124fs in Quebec. The mutation p.Asp124fs causes a severe disease phenotype with delayed myelination and cortical/subcortical brain atrophy. The most noteworthy radiological finding in this Quebec founder mutation is the presence of the temporal cysts that can be used as a marker of the disease. Also, both patients, who are alive, had a history of prenatal supplements taken by their mothers as antiemetic medication with high doses of pyridoxine. In the context of suspected PDE in patients with neonatal refractory seizures, treatment with pyridoxine and/or Pyridoxal-5-phophate has to be started immediately and continued until the results of genetic analysis received. Even with early appropriate treatment, neurological outcome of our patient is still poor.

Chondroitin sulfate proteoglycans as novel drivers of leucocyte infiltration in multiple sclerosis.

Multiple sclerosis presents with profound changes in the network of molecules involved in maintaining central nervous system architecture, the extracellular matrix. The extracellular matrix components, particularly the chondroitin sulfate proteoglycans, have functions beyond structural support including their potential interaction with, and regulation of, inflammatory molecules. To investigate the roles of chondroitin sulfate proteoglycans in multiple sclerosis, we used the experimental autoimmune encephalomyelitis model in a time course study. We found that the 4-sulfated glycosaminoglycan side chains of chondroitin sulfate proteoglycans, and the core protein of a particular family member, versican V1, were upregulated in the spinal cord of mice at peak clinical severity, correspondent with areas of inflammation. Versican V1 expression in the spinal cord rose progressively over the course of experimental autoimmune encephalomyelitis. A particular structure in the spinal cord and cerebellum that presented with intense upregulation of chondroitin sulfate proteoglycans is the leucocyte-containing perivascular cuff, an important portal of entry of immune cells into the central nervous system parenchyma. In these inflammatory perivascular cuffs, versican V1 and the glycosaminoglycan side chains of chondroitin sulfate proteoglycans were observed by immunohistochemistry within and in proximity to lymphocytes and macrophages as they migrated across the basement membrane into the central nervous system. Expression of versican V1 transcript was also documented in infiltrating CD45+ leucocytes and F4/80+ macrophages by in situ hybridization. To test the hypothesis that the chondroitin sulfate proteoglycans regulate leucocyte mobility, we used macrophages in tissue culture studies. Chondroitin sulfate proteoglycans significantly upregulated pro-inflammatory cytokines and chemokines in macrophages. Strikingly, and more potently than the toll-like receptor-4 ligand lipopolysaccharide, chondroitin sulfate proteoglycans increased the levels of several members of the matrix metalloproteinase family, which are implicated in the capacity of leucocytes to cross barriers. In support, the migratory capacity of macrophages in vitro in a Boyden chamber transwell assay was enhanced by chondroitin sulfate proteoglycans. Finally, using brain specimens from four subjects with multiple sclerosis with active lesions, we found chondroitin sulfate proteoglycans to be associated with leucocytes in inflammatory perivascular cuffs in all four patients. We conclude that the accumulation of chondroitin sulfate proteoglycans in the perivascular cuff in multiple sclerosis and experimental autoimmune encephalomyelitis boosts the activity and migration of leucocytes across the glia limitans into the central nervous system parenchyma. Thus, chondroitin sulfate proteoglycans represent a new class of molecules to overcome in order to reduce the inflammatory cascades and clinical severity of multiple sclerosis.

The combination of valacyclovir with an anti-TNF alpha antibody increases survival rate compared to antiviral therapy alone in a murine model of herpes simplex virus encephalitis.

The added benefit of combining valacyclovir (VACV), an antiviral agent, with etanercept (ETA), an anti-tumor necrosis factor alpha (TNF-α) antibody, for the treatment of herpes simplex virus type 1 (HSV-1) encephalitis (HSE) was evaluated in a mouse model. BALB/c mice were infected intranasally with 1.85 × 104 plaque forming units of HSV-1. Groups of mice received a single intraperitoneal injection of vehicle or ETA (400 µg/mouse) on day 3 post-infection combined or not with VACV (1 mg/ml of drinking water) from days 3 to 21 post-infection. On day 5 post-infection, groups of mice were sacrificed for determination of viral DNA load, detection of ETA in brain homogenates and for in situ hybridization. The survival rate of mice was significantly increased when VACV was administered in combination with ETA (38.5% for VACV vs 78.6% for combined treatment; P = 0.04) although VACV or ETA alone had no significant effect compared to the vehicle. The benefit of combined therapy was still present when treatment was delayed until day 4 post-infection. The viral DNA load was significantly reduced in mice treated with VACV alone (P < 0.01) or combined with ETA (P < 0.05) compared to the uninfected group whereas ETA alone had no effect. These results reinforce the notion that both virus-induced and immune-related mechanisms participate in the pathogenesis of HSE and suggest that potent antiviral agent could be combined with immune-based therapy, such as a TNF-α inhibitor, to improve prognosis of HSE.

Powerful beneficial effects of macrophage colony-stimulating factor on beta-amyloid deposition and cognitive impairment in Alzheimer's disease.

Alzheimer's disease is a major cause of dementia in humans. The appearance of cognitive decline is linked to the overproduction of a short peptide called beta-amyloid (Abeta) in both soluble and aggregate forms. Here, we show that injecting macrophage colony-stimulating factor (M-CSF) to Swedish beta-amyloid precursor protein (APP(Swe))/PS1 transgenic mice, a well-documented model for Alzheimer's disease, on a weekly basis prior to the appearance of learning and memory deficits prevented cognitive loss. M-CSF also increased the number of microglia in the parenchyma and decreased the number of Abeta deposits. Senile plaques were smaller and less dense in the brain of M-CSF-treated mice compared to littermate controls treated with vehicle solution. Interestingly, a higher ratio of microglia internalized Abeta in the brain of M-CSF-treated animals and the phagocytosed peptides were located in the late endosomes and lysosomes. Less Abeta(40) and Abeta(42) monomers were also detected in the extracellular protein enriched fractions of M-CSF-treated transgenic mice when compared with vehicle controls. Finally, treating APP(Swe)/PS1 mice that were already demonstrating installed Abeta pathology stabilized the cognitive decline. Together these results provide compelling evidence that systemic M-CSF administration is a powerful treatment to stimulate bone marrow-derived microglia, degrade Abeta and prevent or improve the cognitive decline associated with Abeta burden in a mouse model of Alzheimer's disease.

Role of IL-1 and TNF in the brain: twenty years of progress on a Dr. Jekyll/Mr. Hyde duality of the innate immune system.

The immune-privileged status of the central nervous system (CNS) has changed quite dramatically during the past two decades. Leukocytes have the ability to infiltrate the CNS and cytokines are produced by resident cells, especially during injuries and diseases. Although the cellular source and role of these immune ligands are better known, their exact contribution to brain protection, repair or diseases still remains highly debated today. The ultimate fate of the immune reaction depends on the cytokines involved and the experimental models. It is now generally accepted that microglia play a central role in this response, at least for the production of cytokines participating in the innate immune system. As macrophages, resident microglia produce numerous cytokines and two of them have been largely studied since the beginning of this field of research. Twenty years ago, interleukin 1 (IL-1) and tumor-necrosis factor (TNF) were cloned and recombinant forms were used to investigate their functions ranging from normal neurophysiological responses to pathological conditions. This review presents the history of these two cytokines during immune responses in the brain and where we are now two decades later.

In altering the release of glucocorticoids, ketorolac exacerbates the effects of systemic immune stimuli on expression of proinflammatory genes in the brain.

Nonsteroidal antiinflammatory drugs (NSAIDs) are widely used for their antiinflammatory, antipyretic, and analgesic properties. The molecular basis for the therapeutic action of NSAIDs is believed to be in their ability to inhibit cyclooxygenase (COX) activity and thereby blocking the production of prostaglandins. Emerging evidence now suggests that NSAIDs can exert their pharmacological effects through other mechanisms. This study investigated the influence of a nonselective COX-inhibitor ketorolac on IL-1beta- and TNFalpha-induced expression of proinflammatory genes in the brain. Systemic injection of both cytokines caused a rapid and transient transcriptional activation of COX-2 gene within the cerebral microvasculature, which was significantly enhanced by ketorolac. Expression of genes encoding the index of nuclear factor kappaB activity and the chemokine monocyte chemoattractant protein-1 was also increased by the NSAID. We speculated here that such effect was indirectly mediated via an altered secretion of plasma glucocorticoids because ketorolac is a potent inhibitor of the hypothalamic-pituitary-adrenal axis during systemic inflammation. As expected, pretreatment with the glucocorticoid receptor antagonist RU-486 exacerbated the influence of systemic immune stimuli on proinflammatory signaling. In contrast, exogenous corticosterone abolished the effects of ketorolac on IL-1beta-induced COX-2 and monocyte chemoattractant protein-1 gene expression in the cerebral endothelium. This drug plays therefore a paradoxical role in its ability to inhibit the circulating levels of glucocorticoids that are essential inhibitory feedback on the proinflammatory signal transduction pathways and gene transcription. In altering the production of key prostaglandins that are involved in the control of hypothalamic-pituitary-adrenal axis, ketorolac may have proinflammatory properties in the central nervous system during systemic immune stimuli.