Vitamin D responsive elements within the HLA-DRB1 promoter region in Sardinian multiple sclerosis associated alleles

The impact of genetic variants related to vitamin D and autoimmunity: A systematic review

Over the past few years, there has been a notable increment in scientific literature aimed at unraveling the genetic foundations of vitamin D signaling and its implications for susceptibility to autoimmunity, however, most of them address isolated diseases. Here, we conducted a systematic review of genetic variants related to vitamin D and autoimmune diseases and we discussed the current landscape of susceptibility and outcomes. Of 65 studies analyzed, most variants cited are in vitamin D binding protein (VDBP; rs2282679 GC gene), 25-hydroxylase (rs10751657 CYP2R1), 1α-hydroxylase (rs10877012, CYP27B1) and the nuclear hormone receptor superfamily [FokI (rs2228570), BsmI (rs1544410), ApaI (rs7975232), and TaqI (rs731236) in VDR gene]. Therefore, our findings confirmed the associations of several genetic variants of vitamin D signaling with a broad spectrum of autoimmune diseases/traits. In addition, given the low number of papers found with functional analysis, further studies to elucidate the real effect that the variants exert on Vitamin D signaling are recommended.

The Role of Vitamin D in Neuroprotection in Multiple Sclerosis: An Update

Multiple sclerosis (MS) is a complex neurological condition that involves both inflammatory demyelinating and neurodegenerative components. MS research and treatments have traditionally focused on immunomodulation, with less investigation of neuroprotection, and this holds true for the role of vitamin D in MS. Researchers have already established that vitamin D plays an anti-inflammatory role in modulating the immune system in MS. More recently, researchers have begun investigating the potential neuroprotective role of vitamin D in MS. The active form of vitamin D, 1,25(OH)₂D₃, has a range of neuroprotective properties, which may be important in remyelination and/or the prevention of demyelination. The most notable finding relevant to MS is that 1,25(OH)₂D₃ promotes stem cell proliferation and drives the differentiation of neural stem cells into oligodendrocytes, which carry out remyelination. In addition, 1,25(OH)₂D₃ counteracts neurodegeneration and oxidative stress by suppressing the activation of reactive astrocytes and M1 microglia. 1,25(OH)₂D₃ also promotes the expression of various neuroprotective factors, including neurotrophins and antioxidant enzymes. 1,25(OH)₂D₃ decreases blood-brain barrier permeability, reducing leukocyte recruitment into the central nervous system. These neuroprotective effects, stimulated by 1,25(OH)₂D₃, all enhance neuronal survival. This review summarizes and connects the current evidence supporting the vitamin D-mediated mechanisms of action for neuroprotection in MS.

Multiple Sclerosis in a Patient With Prior West Nile Encephalitis

Multiple sclerosis is a neurodegenerative disease characterized by an inflammatory demyelination of the central nervous system. The degenerative disease has been linked to numerous viral infections, geographical locations, and genetic predisposition. One link that has not been fully established is the relationship between West Nile virus infection and its role in the initiation of multiple sclerosis. This case study provides further evidence that the proinflammatory neurological processes induced by the West Nile virus may lead to systemic demyelination of neuronal axons, ultimately causing multiple sclerosis.

An Update on the Effects of Vitamin D on the Immune System and Autoimmune Diseases

Vitamin D intervenes in calcium and phosphate metabolism and bone homeostasis. Experimental studies have shown that 1,25-dihydroxyvitamin D (calcitriol) generates immunologic activities on the innate and adaptive immune system and endothelial membrane stability. Low levels of serum 25-hydroxyvitamin D (25(OH)D) are associated with an increased risk of developing immune-related diseases such as psoriasis, type 1 diabetes, multiple sclerosis, and autoimmune diseases. Various clinical trials describe the efficacy of supplementation of vitamin D and its metabolites for treating these diseases that result in variable outcomes. Different disease outcomes are observed in treatment with vitamin D as high inter-individual difference is present with complex gene expression in human peripheral blood mononuclear cells. However, it is still not fully known what level of serum 25(OH)D is needed. The current recommendation is to increase vitamin D intake and have enough sunlight exposure to have serum 25(OH)D at a level of 30 ng/mL (75 nmol/L) and better at 40–60 ng/mL (100–150 nmol/L) to obtain the optimal health benefits of vitamin D.

The Potential for EBV Vaccines to Prevent Multiple Sclerosis

There is increasing evidence suggesting that Epstein-Barr virus infection is a causative factor of multiple sclerosis (MS). Epstein-Barr virus (EBV) is a human herpesvirus, Human Gammaherpesvirus 4. EBV infection shows two peaks: firstly, during early childhood and, secondly during the teenage years. Approximately, 90-95% of adults have been infected with EBV and for many this will have been a subclinical event. EBV infection can be associated with significant morbidity and mortality; for example, primary infection in older children or adults is the leading cause of infectious mononucleosis (IM). A disrupted immune response either iatrogenically induced or through genetic defects can result in lymphoproliferative disease. Finally, EBV is oncogenic and is associated with several malignancies. For these reasons, vaccination to prevent the damaging aspects of EBV infection is an attractive intervention. No EBV vaccines have been licensed and the prophylactic vaccine furthest along in clinical trials contains the major virus glycoprotein gp350. In a phase 2 study, the vaccine reduced the rate of IM by 78% but did not prevent EBV infection. An EBV vaccine to prevent IM in adolescence or young adulthood is the most likely population-based vaccine strategy to be tested and adopted. National registry studies will need to be done to track the incidence of MS in EBV-vaccinated and unvaccinated people to see an effect of the vaccine on MS. Assessment of vaccine efficacy with MS being a delayed consequence of EBV infection with the average age of onset being approximately 30 years of age represents multiple challenges.

Impact of Vitamin D Supplementation on Multiple Sclerosis

Multiple sclerosis (MS) is an autoimmune disease affecting a large number of people every year. The exact causal factor for this disease is unclear, but it commonly affects middle-aged women, with known triggers like stress, childbirth, infections, poor diet, lack of sleep, etc.

Many epidemiological studies have indicated that various genetic abnormalities are also critical drivers of the onset of MS. The major risk factors of MS identified include hypovitaminosis D while environmental protective factors include allele HLA DRB1 1501, obesity, Epstein-Barr virus infection, sexual hormones, and smoking.

Our article explores the correlation between the deficiency of vitamin D and the onset and progression of MS. The study uses a systematic review methodology by researching and reviewing scholarly articles exploring the topic. We conducted online searches of literature on Google Scholar and PubMed using the keywords "vitamin D deficiency" and "multiple sclerosis" and accessed the relevant secondary literature sources for review. The variables under study included vitamin D insufficiency as the dependent variable while MS was the independent variable. Causal variables included environmental, genetic, and protective factors.

We hypothesized that there is indeed a correlation between vitamin D deficiency and MS. The findings from our review indicate a strong correlation between the insufficiency of vitamin D and the onset and progression of MS. These results are essential in devising interventions to accomplish primary and secondary prevention of MS, as well as integrating vitamin D supplementation in current treatment protocols for MS.

Identification of 8-Digit HLA-A, -B, -C, and -DRB1 Allele and Haplotype Frequencies in Koreans Using the One Lambda AllType Next-Generation Sequencing Kit

Background

Recent studies have successfully implemented next-generation sequencing (NGS) in HLA typing. We performed HLA NGS in a Korean population to estimate HLA-A, -B, -C, and -DRB1 allele and haplotype frequencies up to an 8-digit resolution, which might be useful for an extended application of HLA results.

Methods

A total of 128 samples collected from healthy unrelated Korean adults, previously subjected to Sanger sequencing for 6-digit HLA analysis, were used. NGS was performed for HLA-A, -B, -C, and -DRB1 using the AllType NGS kit (One Lambda, West Hills, CA, USA), Ion Torrent S5 platform (Thermo Fisher Scientific, Waltham, MA, USA), and Type Steam Visual NGS analysis software (One Lambda).

Results

Eight HLA alleles showed frequencies of ≥10% in the Korean population, namely, A*24:02:01:01 (19.5%), A*33:03:01 (15.6%), A*02:01:01:01 (14.5%), A*11:01:01:01 (13.3%), B*15:01:01:01 (10.2%), C*01:02:01 (19.9%), C*03:04:01:02 (11.3%), and DRB1*09:01:02 (10.2%). Nine previous 6-digit HLA alleles were further identified as two or more 8-digit HLA alleles. Of these, eight alleles (A*24:02:01, B*35:01:01, B*40:01:02, B*55:02:01, B*58:01:01, C*03:02:02, C*07:02:01, and DRB1*07:01:01) were identified as two 8-digit HLA alleles, and one allele (B*51:01:01) was identified as three 8-digit HLA alleles. The most frequent four-loci haplotype was HLA-A*33:03:01-B*44:03:01:01-C*14:03-DRB1*13:02:01.

Conclusions

We identified 8-digit HLA-A, -B, -C, and -DRB1 allele and haplotype frequencies in a healthy Korean population using NGS. These new data can be used as a representative Korean data for further disease-related HLA type analysis.

Association of Vitamin D Metabolism Gene Polymorphisms with Autoimmunity: Evidence in Population Genetic Studies

A high prevalence of vitamin D (calcidiol) serum deficiency has been described in several autoimmune diseases, including multiple sclerosis (MS), rheumatoid arthritis (AR), and systemic lupus erythematosus (SLE). Vitamin D is a potent immunonutrient that through its main metabolite calcitriol, regulates the immunomodulation of macrophages, dendritic cells, T and B lymphocytes, which express the vitamin D receptor (VDR), and they produce and respond to calcitriol. Genetic association studies have shown that up to 65% of vitamin D serum variance may be explained due to genetic background. The 90% of genetic variability takes place in the form of single nucleotide polymorphisms (SNPs), and SNPs in genes related to vitamin D metabolism have been linked to influence the calcidiol serum levels, such as in the vitamin D binding protein (VDBP; rs2282679 GC), 25-hydroxylase (rs10751657 CYP2R1), 1α-hydroxylase (rs10877012, CYP27B1) and the vitamin D receptor (FokI (rs2228570), BsmI (rs1544410), ApaI (rs7975232), and TaqI (rs731236) VDR). Therefore, the aim of this comprehensive literature review was to discuss the current findings of functional SNPs in GC, CYP2R1, CYP27B1, and VDR associated to genetic risk, and the most common clinical features of MS, RA, and SLE.

Monocytic Cytokines in Autoimmune Polyglandular Syndrome Type 2 Are Modulated by Vitamin D and HLA-DQ

Context

Autoimmune polyglandular syndrome (APS-2: autoimmune Addison’s disease or type 1 diabetes) is conferred by predisposing HLA molecules, vitamin D deficiency, and heritable susceptibility. Organ destruction is accompanied by cytokine alterations. We addressed the monocytic cytokines of two distinct APS-2 cohorts, effects of vitamin D and HLA DQ risk.

Methods

APS-2 patients (n = 30) and healthy controls (n = 30) were genotyped for HLA DQA1/DQB1 and their CD14+ monocytes stimulated with IL1β and/or 1,25(OH)₂D₃ for 24 h. Immune regulatory molecules (IL-6, IL-10, IL-23A, IL-15, CCL-2, PD-L1), vitamin D pathway gene transcripts (CYP24A1, CYP27B1, VDR), and CD14 were analyzed by enzyme-linked immunosorbent assay and RTqPCR.

Results

Pro-inflammatory CCL-2 was higher in APS-2 patients than in controls (p = 0.001), whereas IL-6 showed a trend – (p = 0.1). In vitro treatment with 1,25(OH)₂D₃ reduced proinflammatory cytokines (IL-6, CCL-2, IL-23A, IL-15) whereas anti-inflammatory cytokines (IL-10 and PD-L1) rose both in APS-type 1 diabetes and APS-Addison´s disease. Patients with adrenal autoimmunity showed a stronger response to vitamin D. Expression of IL-23A and vitamin D pathway genes VDR and CYP27B1 varied by HLA genotype and was lower in healthy individuals with high-risk HLA (p = 0.0025; p = 0.04), while healthy controls with low-risk HLA showed a stronger IL-10 and CD14 expression (p = 0.01; p = 0.03).

Conclusion

1,25(OH)₂D₃ regulates the monocytic response in APS-2 disorders type 1 diabetes or Addison´s disease. The monocytic cytokine profile of individuals carrying HLA high-risk alleles is proinflammatory, enhances polyglandular autoimmunity and can be targeted by vitamin D.

Effect of Vitamin D on Experimental Autoimmune Neuroinflammation Is Dependent on Haplotypes Comprising Naturally Occurring Allelic Variants of CIITA (Mhc2ta)

An increasing body of evidence associates low vitamin D levels with increased risk of multiple sclerosis (MS), suggesting the possibility of a gene-environment interaction for this environmental factor in MS pathogenesis. Moreover, it has been shown that vitamin D downregulates major histocompatibility complex (MHC) class II expression in experimental autoimmune encephalomyelitis (EAE), an animal model of MS. We here report about the impact of a dietary vitamin D supplementation on EAE in the rat strains having functionally relevant allelic variations in the CIITA (Mhc2ta) gene, a master regulator of MHC class II expression. Full length myelin oligodendrocyte glycoprotein (MOG)-EAE was induced in DA.PVG^av1-Vra4 congenic rats harboring the Vra4 locus from PVG strain in the EAE- susceptible DA background, and compared to the parental strains. The congenic rats fed with either vitamin D supplemented, deprived or regular diet developed an intermediate clinical EAE phenotype, in contrast to DA and PVG strains. Immunopathological studies revealed vitamin D dose-dependent effect on demyelination and inflammatory infiltration of the central nervous system (CNS), expression of MHC class II and CIITA, as well as downregulation of a range of pro-inflammatory genes. Taken together, our findings demonstrate an impact of vitamin D on the target tissue pathology and peripheral immune response during EAE in DA.PVG^av1-Vra4 congenic strain. Thereby, our data provide evidence of a modulatory effect of vitamin D in context of genetic variances in the Vra4 locus/Mhc2ta gene in MS-like neuroinflammation, with potential relevance for the human demyelinating disease.

Immunologic Effects of Vitamin D on Human Health and Disease

Vitamin D is responsible for regulation of calcium and phosphate metabolism and maintaining a healthy mineralized skeleton. It is also known as an immunomodulatory hormone. Experimental studies have shown that 1,25-dihydroxyvitamin D, the active form of vitamin D, exerts immunologic activities on multiple components of the innate and adaptive immune system as well as endothelial membrane stability. Association between low levels of serum 25-hydroxyvitamin D and increased risk of developing several immune-related diseases and disorders, including psoriasis, type 1 diabetes, multiple sclerosis, rheumatoid arthritis, tuberculosis, sepsis, respiratory infection, and COVID-19, has been observed. Accordingly, a number of clinical trials aiming to determine the efficacy of administration of vitamin D and its metabolites for treatment of these diseases have been conducted with variable outcomes. Interestingly, recent evidence suggests that some individuals might benefit from vitamin D more or less than others as high inter-individual difference in broad gene expression in human peripheral blood mononuclear cells in response to vitamin D supplementation has been observed. Although it is still debatable what level of serum 25-hydroxyvitamin D is optimal, it is advisable to increase vitamin D intake and have sensible sunlight exposure to maintain serum 25-hydroxyvitamin D at least 30 ng/mL (75 nmol/L), and preferably at 40-60 ng/mL (100-150 nmol/L) to achieve the optimal overall health benefits of vitamin D.

An integrative cognitive rehabilitation using neurologic music therapy in multiple sclerosis: A pilot study

BACKGROUND

Multiple sclerosis (MS) is a demyelinating disease, affecting both the sensorimotor and cognitive systems. The typical pattern of cognitive impairment includes reduced speed of information processing, decreased phonological and semantic speech fluency, deficits in verbal and visual episodic memory, as well as attention and executive dysfunctions. We aimed to investigate the influence of the neurologic music therapy (NMT) on mood, motivation, emotion status, and cognitive functions in patients with MS.

METHODS

Thirty patients with MS were randomly divided in 2 groups: the control group (CG) undergoing conventional cognitive rehabilitation (CCR), 6 times a week for 8 weeks, and the experimental group (EG) undergoing CCR 3 times a week for 8 weeks plus NMT techniques, performed 3 times a week for 8 weeks. All the participants were submitted to the same amount of treatment. Each patient was evaluated before (baseline: T0) and immediately after the end of each training (T1).

MAIN OUTCOMES MEASURES

We used as main outcome measure: the brief repeatable battery of neuropsychological test to assess various cognitive abilities; and the multiple sclerosis quality of life-54 (MSQoL-54).

RESULTS

Both the groups benefit from 8 weeks of CR. In particular, the EG got better results in cognitive function, with regard to selective reminding test long term storage (P < .000), long term retrieval (P = .007), and delayed recall of the 10/36 spatial recall test (P = .001), as compared with the CG. Moreover, the improvement in emotional status, motivation, mood and quality of life (with regard to the mental component; P < .000) was more evident in the EG.

CONCLUSIONS

NMT could be considered a complementary approach to enhance CCR in patients affected by MS.

Molecular evidence of role of vitamin D deficiency in various extraskeletal diseases

BACKGROUND

Role of vitamin D is not only limited to skeletal system but various other systems of the body, such as immune system, endocrine system, and cardiopulmonary system.

MATERIALS AND METHODS

It is supported by the confirmations of systems-wide expression of vitamin D receptor (VDR), endocrinal effect of calcitriol, and its role in immune responses.

RESULTS

Expression of VDR in various systems, immunoregulatory and hormonal response of vitamin D and deficiency of vitamin D may establish various pathologies in the body.

CONCLUSION

This review provides molecular evidence of relation of vitamin D with extra skeletal.

Performance in daily activities, cognitive impairment and perception in multiple sclerosis patients and their caregivers

Background

The relationship between cognitive assessment results in multiple sclerosis (MS) and performance in daily activities (DAs) remains unclear. Our study aimed to evaluate the relationship between cognitive functions (CF) measured by tests, performance in DAs, and the perception of CF in patients and their caregivers (CG) in MS.

Methods

The Brief International Cognitive Assessment for Multiple Sclerosis (BICAMS) battery was used to evaluate cognitive status. We created an ad hoc questionnaire (DaQ) to assess performance in DAs not requiring specific motor skills. We used the Multiple Sclerosis Neuropsychological Questionnaire (MSNQ) to measure each patient self-judgment and caregiver’s perception of CF.

Results

Forty-nine patients and their caregivers were included in the study. Significant correlations were found between the BICAMS and the DaQ (Symbol Digit Modalities Test (SDMT): r = − 0.48, p < 0.001; California Verbal Learning Test (CVLT): r = − 0.33, p = 0.01; Brief Visual Memory Test (BVMT-R): r = − 0.42; p = 0.002); patients self-judgment (SDMT: r = − 0.38, p = 0.004; CVLT: r = − 0.26, p = 0.03); caregiver perception of patient’s CF (SDMT: r = − 0.52, p < 0.001; CVLT: r = − 0.3, p = 0.01; BVMT-R: r = − 0.42, p = 0.002). The difference in perception between the patients and their caregivers was related to patient age (p = 0.001) and severity of cognitive impairment (p = 0.03).

Conclusions

Cognitive assessment results show a significant correlation with performance in daily activities and with patients and, especially, caregiver perception of cognitive impairment. These data support the importance of a routine evaluation of cognitive function in MS that includes an anamnestic evaluation of patients, and, when possible, consideration of the caregiver’s point of view.

Electronic supplementary material

The online version of this article (10.1186/s12883-018-1224-z) contains supplementary material, which is available to authorized users.

Topics on vitamin D in systemic lupus erythematosus: analysis of evidence and critical literature review

Systemic lupus erythematosus (SLE) is a systemic autoimmune disease with multiorgan inflammation, linked to the loss of immune tolerance to self-antigens and the production of a diversity of autoantibodies. The phenotype and progression of SLE have been linked to a combination of environmental, genetic, and hormonal factors. One such environmental factor is vitamin D, a vital hormone with well-established effects on mineral metabolism, skeletal health, and effects on cardiovascular system. The purpose of this article is to make the analysis of evidence and literature review of the pleomorphic effects of Vitamin D in SLE. The article is structured in topics of interest based in the authors' opinion and summarizes the evidence of studies and trials of vitamin D in SLE.

Cognition in multiple sclerosis: Between cognitive reserve and brain volume

BACKGROUND

Several correlations between cognitive impairment (CI), radiologic markers and cognitive reserve (CR) have been documented in MS.

OBIECTIVE

To evaluate correlation between CI and brain volume (BV) considering CR as possibile mitigating factor.

METHODS

195 relapsing MS patients underwent a neuropsychological assessment using BICAMS. BV was estimated using SIENAX to obtain normalized volume of brain (NBV), white matter (NWV), gray matter (NGV) and cortical gray matter (CGV). CR was estimated using a previously validated tool.

RESULTS

Pearson test showed a correlation between the symbol digit modality test (SDMT) score and NBV (r=0.38; p<0.000) NGV(r=0.31; p<0.000), CGV (r=0.35; p<0.000) and CRI score(r=0.42; p<0.000). Linear regression (dependent variable:SDMT) showed a relationship with CR scores (p=0.000) and NGV(p<0.000). A difference was detected between cognitive impaired and preserved patients regarding mean of NBV(p=0.002), NGV(p=0.007), CGV(p=0.002) and CR Scores (p=0.007). Anova showed a association between the presence of CI (dependent variable) and the interaction term CRIQ × CGV (p=0.004) whit adjustment for age and disability evaluated by EDSS.

CONCLUSIONS

Our study shows a correlation between cognition and BV, in particular gray matter volume. Cognitive reserve is also confirmed as an important element playing a role in the complex interaction to determine the cognitive functions in MS.

Multiple sclerosis and HLA genotypes: A possible influence on brain atrophy

BACKGROUND

The strongest genetic determinant for multiple sclerosis (MS) is located at the human leukocyte antigen (HLA) class II DRB1 and DQB1 loci.

OBJECTIVES

To investigate the possible role of predisposing HLA genotypes in determining brain atrophy.

METHODS

HLA genotypes were categorized as high risk (two predisposing haplotypes) or medium/low risk (one or no predisposing haplotypes). Patients underwent a brain magnetic resonance imaging (MRI) study and volumes of white matter (WM), gray matter (GM), and whole brain (WB) were estimated with SIENAX. Longitudinal atrophy was also assessed with SIENA.

RESULTS

The study included 240 MS patients. In 51/240 (21%) subjects, a high-risk HLA genotype was observed, while medium- and low-risk HLA genotypes were 109/240 (45%) and 80/240 (34%), respectively. Multiple regression analysis found that the high-risk HLA genotype was associated with significant reduction in WB ( p = 0.02) and GM ( p = 0.03) volumes compared with the medium-/low-risk HLA genotypes, independently from MS clinical features. The longitudinal study included 60 patients and showed a brain volume loss of -0.79% in high-risk HLA genotype group versus -0.56% in low-risk HLA genotype.

CONCLUSION

Our results suggest an influence of HLA genotype on WB and GM atrophy. Further investigations are necessary to confirm these findings.

Vitamin D modulates the expression of HLA-DR and CD38 after in vitro activation of T-cells

OBJECTIVE

Vitamin D (VitD) is an anti-inflammatory hormone; however, some evidence shows that VitD may induce the expression of activation markers, such as CD38 and HLA-DR. We explored its effect on the expression of these markers on CD4+ and CD8+ T-cells in vitro, and their potential correlations in vivo.

MATERIALS AND METHODS

CD38 and HLA-DR expression was measured by flow cytometry in PHA/IL-2-activated mononuclear cells cultured under VitD precursors: three cholecalciferol (10-11M, 10-9M, 10-7M; n=11) and two calcidiol (40 ng/mL, 80 ng/mL; n=9) concentrations. The correlation between the expression of these markers in freshly isolated blood cells and serum levels of calcidiol was also explored (n=10).

RESULTS

Cholecalciferol at 10-7M increased the proportion of CD4+ CD38+ and CD8+ CD38+ cells, and decreased CD8+HLA-DR+ cells. As co-expression, it increased the CD38+HLA-DR- and decreased CD38-HLA-DR+ subpopulations in both CD4+ and CD8+ T-cells, and decreased CD4+CD38-HLA-DR- and CD8+ CD38+HLA-DR+; whereas both calcidiol concentrations decreased the proliferation of CD38-HLA-DR- and CD38-HLA-DR+ subpopulations. Both forms of VitD increased the number of CD38 molecules per cell. In contrast, there was a positive but non-significant correlation between serum calcidiol levels and the expression of CD38 and HLA-DR in CD4+ and CD8+ T-cells.

CONCLUSION

Although no significant correlations were observed in vivo in healthy subjects, VitD treatment in vitro modulated immune activation by increasing the expression of CD38 and decreasing the proliferation of HLA-DR+ and resting cells, which may correlate with improved effector and decreased proliferative capabilities. These results highlight the potential use of VitD as therapeutic strategy in immune disorders.

Association of serum 25-hydroxyvitamin D concentration with HLA-B, -DRB1 and -DQB1 genetic polymorphisms

BACKGROUND/OBJECTIVES

The human leukocyte antigen (HLA) gene region associates with the risk for several autoimmune diseases, including type 1 diabetes. An association between vitamin D deficiency and several autoimmune diseases has been suggested. We tested the association between serum 25-hydroxyvitamin D (25OHD) concentrations and HLA alleles in pregnant Finnish women.

SUBJECTS/METHODS

HLA-B (n=395), HLA-DRB1 (n=501) and HLA-DQB1 (n=475) alleles were genotyped in pregnant women (mothers of children who later developed type 1 diabetes and mothers of non-diabetic children). HLA-B alleles were divided into supertypes that share similar peptide-binding specificity. Serum 25OHD concentration had been previously measured in these women from sera collected during the first trimester of pregnancy. Multiple testing was controlled for using the false discovery rate method.

RESULTS

An association was found between 25OHD concentration and HLA-B44 supertype (P=0.009); women with HLA-B44 supertype (B*18, B*37, B*40 and B*44 alleles) had lower 25OHD concentrations. No association was found between HLA-DRB1 or -DQB1 alleles and 25OHD concentration.

CONCLUSIONS

In this study we found for the first time an association between HLA genetic polymorphisms and 25OHD concentration. In future studies, the mechanistic background of this association and the role of vitamin D in the regulation of HLA gene expression should be investigated.

[The role of the solar and geomagnetic activity in the etiology of multiple sclerosis: a review of the literature and prospects of research]

Despite the great progress in the study of multiple sclerosis (MS), its etiology remains unknown. It is proved that MS occurs in genetically predisposed people under the influence of environmental factors. Among these factors the solar activity (SA) and geomagnetic activity (GA) attract the particular attention. This article presents the review of studies concerning the influence of SA and GA on the incidence and course of MS.

Relationship of structure and function of DNA-binding domain in vitamin D receptor

While the structure of the DNA-binding domain (DBD) of the vitamin D receptor (VDR) has been determined in great detail, the roles of its domains and how to bind the motif of its target genes are still under debate. The VDR DBD consists of two zinc finger modules and a C-terminal extension (CTE), at the end of the C-terminal of each structure presenting α-helix. For the first zinc finger structure, N37 and S-box take part in forming a dimer with 9-cis retinoid X receptor (RXR), while V26, R50, P-box and S-box participate in binding with VDR response elements (VDRE). For the second zinc finger structure, P61, F62 and H75 are essential in the structure of the VDR homodimer with the residues N37, E92 and F93 of the downstream of partner VDR, which form the inter-DBD interface. T-box of the CTE, especially the F93 and I94, plays a critical role in heterodimerization and heterodimers-VDRE binding. Six essential residues (R102, K103, M106, I107, K109, and R110) of the CTE α-helix of VDR construct one interaction face, which packs against the DBD core of the adjacent symmetry mate. In 1,25(OH)2D3-activated signaling, the VDR-RXR heterodimer may bind to DR3-type VDRE and ER9-type VDREs of its target gene directly resulting in transactivation and also bind to DR3-liked nVDRE of its target gene directly resulting in transrepression. Except for this, 1α,25(OH)2D3 ligand VDR-RXR may bind to 1αnVDRE indirectly through VDIR, resulting in transrepression of the target gene. Upon binding of 1α,25(OH)2D3, VDR can transactivate and transrepress its target genes depending on the DNA motif that DBD binds.

Phase-defined complete sequencing of the HLA genes by next-generation sequencing

BACKGROUND

The human leukocyte antigen (HLA) region, the 3.8-Mb segment of the human genome at 6p21, has been associated with more than 100 different diseases, mostly autoimmune diseases. Due to the complex nature of HLA genes, there are difficulties in elucidating complete HLA gene sequences especially HLA gene haplotype structures by the conventional sequencing method. We propose a novel, accurate, and cost-effective method for generating phase-defined complete sequencing of HLA genes by using indexed multiplex next generation sequencing.

RESULTS

A total of 33 HLA homozygous samples, 11 HLA heterozygous samples, and 3 parents-child families were subjected to phase-defined HLA gene sequencing. We applied long-range PCR to amplify six HLA genes (HLA-A, -C, -B, DRB1, -DQB1, and -DPB1) followed by transposase-based library construction and multiplex sequencing with the MiSeq sequencer. Paired-end reads (2 × 250 bp) derived from the sequencer were aligned to the six HLA gene segments of UCSC hg19 allowing at most 80 bases mismatch. For HLA homozygous samples, the six amplicons of an individual were pooled and simultaneously sequenced and mapped as an individual-tagging method. The paired-end reads were aligned to corresponding genes of UCSC hg19 and unambiguous, continuous sequences were obtained. For HLA heterozygous samples, each amplicon was separately sequenced and mapped as a gene-tagging method. After alignments, we detected informative paired-end reads harboring SNVs on both forward and reverse reads that are used to separate two chromosomes and to generate two phase-defined sequences in an individual. Consequently, we were able to determine the phase-defined HLA gene sequences from promoter to 3'-UTR and assign up to 8-digit HLA allele numbers, regardless of whether the alleles are rare or novel. Parent-child trio-based sequencing validated our sequencing and phasing methods.

CONCLUSIONS

Our protocol generated phased-defined sequences of the entire HLA genes, resulting in high resolution HLA typing and new allele detection.

Contribution of vitamin D insufficiency to the pathogenesis of multiple sclerosis

The contribution of vitamin D insufficiency to the pathogenesis of multiple sclerosis (MS) is reviewed. Among the multiple recently discovered actions of vitamin D, an immunomodulatory role has been documented in experimental autoimmune encephalomyelitis and in humans. This action in the peripheral immune system is currently the main known mechanism through which vitamin D might influence MS, but other types of actions could be involved within the central nervous system. Furthermore, vitamin D insufficiency is widespread in temperate countries and in patients with MS at the earliest stages of the disease, suggesting that the deleterious effects related to vitamin D insufficiency may be exerted in these patients. In fact, many genetic and environmental risk factors appear to interact and contribute to MS. In genetics, several human leukocyte antigen (HLA) alleles (more particularly HLA-DRB1*1501) could favour the disease whereas some others could be protective. Some of the genes involved in vitamin D metabolism (e.g. CYP27B1) also play a significant role. Furthermore, three environmental risk factors have been identified: past Epstein-Barr virus infection, vitamin D insufficiency and cigarette smoking. Interactions between genetic and environmental risk or protective factors may occur during the mother's pregnancy and could continue during childhood and adolescence and until the disease is triggered in adulthood, therefore possibly modulating the MS risk throughout the first decades of life. Furthermore, some clinical findings already strongly suggest that vitamin D status influences the relapse rate and radiological lesions in patients with MS, although the results of adequately powered randomized clinical trials using vitamin D supplementation have not yet been reported. While awaiting these incontrovertible results, which might be long in coming, patients with MS who are currently in vitamin D insufficiency should be supplemented, at least for their general health status, using moderate doses of the vitamin.