Vitamins D3 and D2 have marked but different global effects on gene expression in a rat oligodendrocyte precursor cell line

Guggulsterone Selectively Modulates STAT-3, mTOR, and PPAR-Gamma Signaling in a Methylmercury-Exposed Experimental Neurotoxicity: Evidence from CSF, Blood Plasma, and Brain Samples

Amyotrophic lateral sclerosis (ALS) is a paralytic disease that damages the brain and spinal cord motor neurons. Several clinical and preclinical studies have found that methylmercury (MeHg+) causes ALS. In ALS, MeHg+-induced neurotoxicity manifests as oligodendrocyte destruction; myelin basic protein (MBP) deficiency leads to axonal death. ALS development has been connected to an increase in signal transducer and activator of transcription-3 (STAT-3), a mammalian target of rapamycin (mTOR), and a decrease in peroxisome proliferator-activated receptor (PPAR)-gamma. Guggulsterone (GST), a plant-derived chemical produced from Commiphorawhighitii resin, has been found to protect against ALS by modulating these signaling pathways. Vitamin D3 (VitD3) deficiency has been related to oligodendrocyte precursor cells (OPC) damage, demyelination, and white matter deterioration, which results in motor neuron death. As a result, the primary goal of this work was to investigate the therapeutic potential of GST by altering STAT-3, mTOR, and PPAR-gamma levels in a MeHg+-exposed experimental model of ALS in adult rats. The GST30 and 60 mg/kg oral treatments significantly improved the behavioral, motor, and cognitive dysfunctions and increased remyelination, as proven by the Luxol Fast Blue stain (LFB), and reduced neuroinflammation as measured by histological examinations. Furthermore, the co-administration of VitD3 exhibits moderate efficacy when administered in combination with GST60. Our results show that GST protects neurons by decreasing STAT-3 and mTOR levels while increasing PPAR-gamma protein levels in ALS rats.

Impact of calcitriol and PGD2-G-loaded lipid nanocapsules on oligodendrocyte progenitor cell differentiation and remyelination

Multiple sclerosis (MS) is a demyelinating and inflammatory disease of the central nervous system (CNS) in need of a curative treatment. MS research has recently focused on the development of pro-remyelinating treatments and neuroprotective therapies. Here, we aimed at favoring remyelination and reducing neuro-inflammation in a cuprizone mouse model of brain demyelination using nanomedicines. We have selected lipid nanocapsules (LNC) coated with the cell-penetrating peptide transactivator of translation (TAT), loaded with either a pro-remyelinating compound, calcitriol (Cal-LNC TAT), or an anti-inflammatory bioactive lipid, prostaglandin D2-glycerol ester (PGD2-G) (PGD2-G-LNC TAT). Following the characterization of these formulations, we showed that Cal-LNC TAT in combination with PGD2-G-LNC TAT increased the mRNA expression of oligodendrocyte differentiation markers both in the CG-4 cell line and in primary mixed glial cell (MGC) cultures. However, while the combination of Cal-LNC TAT and PGD2-G-LNC TAT showed promising results in vitro, no significant impact, in terms of remyelination, astrogliosis, and microgliosis, was observed in vivo in the corpus callosum of cuprizone-treated mice following intranasal administration. Thus, although calcitriol's beneficial effects have been abundantly described in the literature in the context of MS, here, we show that the different doses of calcitriol tested had a negative impact on the mice well-being and showed no beneficial effect in the cuprizone model in terms of remyelination and neuro-inflammation, alone and when combined with PGD2-G-LNC TAT.

Full spectrum of vitamin D immunomodulation in multiple sclerosis: mechanisms and therapeutic implications

Vitamin D deficiency has been associated with the risk of multiple sclerosis, disease activity and progression. Results from in vitro experiments, animal models and analysis of human samples from randomized controlled trials provide comprehensive data illustrating the pleiotropic actions of Vitamin D on the immune system. They globally result in immunomodulation by decreasing differentiation of effector T and B cells while promoting regulatory subsets. Vitamin D also modulates innate immune cells such as macrophages, monocytes and dendritic cells, and acts at the level of the blood–brain barrier reducing immune cell trafficking. Vitamin D exerts additional activity within the central nervous system reducing microglial and astrocytic activation. The immunomodulatory role of Vitamin D detected in animal models of multiple sclerosis has suggested its potential therapeutic use for treating multiple sclerosis. In this review, we focus on recent published data describing the biological effects of Vitamin D in animal models of multiple sclerosis on immune cells, blood–brain barrier function, activation of glial cells and its potential neuroprotective effects. Based on the current knowledge, we also discuss optimization of therapeutic interventions with Vitamin D in patients with multiple sclerosis, as well as new technologies allowing in-depth analysis of immune cell regulations by vitamin D.

Vitamins D2 and D3 Have Overlapping But Different Effects on the Human Immune System Revealed Through Analysis of the Blood Transcriptome

Vitamin D is best known for its role in maintaining bone health and calcium homeostasis. However, it also exerts a broad range of extra-skeletal effects on cellular physiology and on the immune system. Vitamins D₂ and D₃ share a high degree of structural similarity. Functional equivalence in their vitamin D-dependent effects on human physiology is usually assumed but has in fact not been well defined experimentally. In this study we seek to redress the gap in knowledge by undertaking an in-depth examination of changes in the human blood transcriptome following supplementation with physiological doses of vitamin D₂ and D₃. Our work extends a previously published randomized placebo-controlled trial that recruited healthy white European and South Asian women who were given 15 µg of vitamin D₂ or D₃ daily over 12 weeks in wintertime in the UK (Nov-Mar) by additionally determining changes in the blood transcriptome over the intervention period using microarrays. An integrated comparison of the results defines both the effect of vitamin D₃ or D₂ on gene expression, and any influence of ethnic background. An important aspect of this analysis was the focus on the changes in expression from baseline to the 12-week endpoint of treatment within each individual, harnessing the longitudinal design of the study. Whilst overlap in the repertoire of differentially expressed genes was present in the D₂ or D₃-dependent effects identified, most changes were specific to either one vitamin or the other. The data also pointed to the possibility of ethnic differences in the responses. Notably, following vitamin D₃ supplementation, the majority of changes in gene expression reflected a down-regulation in the activity of genes, many encoding pathways of the innate and adaptive immune systems, potentially shifting the immune system to a more tolerogenic status. Surprisingly, gene expression associated with type I and type II interferon activity, critical to the innate response to bacterial and viral infections, differed following supplementation with either vitamin D₂ or vitamin D₃, with only vitamin D₃ having a stimulatory effect. This study suggests that further investigation of the respective physiological roles of vitamin D₂ and vitamin D₃ is warranted.

Gene expression profiles of YAP1, TAZ, CRB3, and VDR in familial and sporadic multiple sclerosis among an Iranian population

Alterations in the regulatory mechanisms that control the process of myelination in the nervous system, may lead to the impaired myelination in the Multiple sclerosis. The Hippo pathway is an important mediator of myelination in the nervous system and might contribute to the pathophysiology of MS. This study examined via qPCR the RNA expression of YAP1, TAZ, and CRB3 as the key effectors of the Hippo pathway and also, VDR in the peripheral blood of 35 sporadic, 37 familial MS patients; and also 34 healthy first-degree relatives of the familial MS patients (HFR) and 40 healthy individuals without a family history of the disease (control). The results showed the increased expression of VDR in the sporadic group, as compared to other groups. There was also an increased expression of TAZ in the familial and HFR groups, as compared to the control group. The familial and sporadic patients displayed a significantly lower level of expression of YAP1 in comparison to the HFR group. The increased expression level in the sporadic patients and control group, as compared to the HFR group, was seen in CRB3. We also assessed different clinical parameters and MRI characteristics of the patients. Overall, these findings suggest that Hippo pathway effectors and also VDR gene may play a potential role in the pathophysiology of the sporadic and familial forms of MS. Confirmation of different gene expression patterns in sporadic and familial MS groups may have obvious implications for the personalization of therapies in the disease.

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