Cellular and Molecular Mechanisms Involved in the Action of Vitamin D Analogs Targeting Vitiligo Depigmentation

Mycobacterium tuberculosis, autoimmunity, and vitamin D

Mycobacterium tuberculosis (TB) is a major cause of morbidity and mortality worldwide. Current anti-TB chemotherapies, although effective, are associated with side effects and are limited in treating drug-resistant strands. Autoimmune diseases are a leading cause of morbidity and mortality, with a growing mass of evidence implicating infections (e.g., TB) as their triggers. The burden of TB might further increase by reactivation threats hovering over millions harboring latent infection, thus, calling for novel approaches for this dire ailment. In recent years, the non-calcemic physiological actions of vitamin D have drawn a great deal of attention. In this review, we will focus on the role of vitamin D in the innate immune defense against TB on the one hand and conversely on the immunomodulatory effects of vitamin D on autoimmunity. Taken together, the suggested dual role of vitamin D in treating TB infection and possibly preventing associated autoimmunity will constitute the basis of the current review.

Defining and analyzing geoepidemiology and human autoimmunity

Autoimmune diseases cumulatively affect 5-10% of the industrial world population and are a significant cause of morbidity and mortality. In recent decades rates are rising worldwide, and autoimmunity can no longer be associated solely with the more developed "Western" countries. Geoepidemiology of autoimmune diseases portrays the burden of these illnesses across various regions and ethnic populations. Furthermore, Geoepidemiology may yield important clues to the genetic and triggering environmental mechanisms of autoimmunity. In this review we compiled and discuss in depth abundant geoepidemiological data pertaining to four major autoimmune conditions, namely type-1 diabetes mellitus, multiple sclerosis, autoimmune thyroid disease, and inflammatory bowel disease. The following key results manifested in this review: 1) Ethno-geographic gradients in autoimmune disease risk are attributable to a complex interplay of genetic and environmental pressures. 2) Industrial regions, particularly Northern Europe and North America, still exhibit the highest rates for most autoimmune diseases. 3) Methods particularly useful in demonstrating the significant influence of genetic and environmental factors include comparative ethnic differences studies, migration studies, and recognition of 'hotspots'. 4) Key environmental determinants of geographical differences include diminished ultraviolet radiation exposure, Western or affluence-related lifestyle, infection exposure, environmental pollutants, nutritional factors and disease-specific precipitants (e.g., iodine exposure).

Association of exon 9 but not intron 8 VDR polymorphisms with occult HBV infection in south-eastern Iranian patients

BACKGROUND AND AIM

Occult hepatitis B infection (OBI) is characterized as a form of hepatitis in which, despite the absence of detectable hepatitis B surface antigen (HBsAg), hepatitis B virus DNA (HBV-DNA) is present in a patient's peripheral blood. Investigators believe that divergent genetics and immunological parameters vary between resistant individuals and patients with OBI. Vitamin D3 and its known receptor appear to be involved in antiviral immune responses. Therefore, because OBI is a form of viral infection, the aim of this study was to investigate the association between polymorphisms in intron 8 and exon 9 of the vitamin D receptor (VDR) with OBI.

METHODS

In this experimental study, the plasma samples of 3700 blood donors were collected and tested for HBsAg and anti-HBs using ELISA. The HBsAg(-)/anti-HBc(+) samples were selected and screened for HBV-DNA using polymerase chain reaction (PCR). HBV-DNA-positive samples assigned as OBI cases and PCR-restricted fragment length polymorphism.

RESULTS

The results of the current study demonstrated that 352 (9.5%) of 3700 blood samples were HbsAg(-)/anti-HBc(+). HBV-DNA was detected in 57/352 (16.1%) of HBsAg(-)/anti-HBc(+) samples. Our results showed a significant difference in the T/T allele of exon 9 of VDR, but any differences were also observed in the other examined alleles.

CONCLUSION

The polymorphisms in the T/T allele of exon 9 of VDR is possibly associated with OBI, thus it can be concluded that VDR and its functional polymorphisms are likely to be related to sensitivity and resistance of the immune system to HBV in OBI patients.

The vitamin D3 transcriptomic response in skin cells derived from the Atlantic bottlenose dolphin

The Atlantic bottlenose dolphin has attracted attention due to the evident impact that environmental stressors have taken on its health. In order to better understand the mechanisms linking environmental health with dolphin health, we have established cell cultures from dolphin skin as in vitro tools for molecular evaluations. The vitamin D3 pathway is one mechanism of interest because of its well established chemopreventative and immunomodulatory properties in terrestrial mammals. On the other hand, little is known of the physiological role of this molecule in aquatic animals. 1,25-dihydroxyvitamin D3 (1,25D3), the bioactive and hormonal form of vitamin D3, exerts its biological function by binding to the vitamin D receptor (VDR), a ligand-activated regulator of gene transcription. Therefore, we investigated the transcriptomic changes induced by 1,25D3 administration in dolphin skin cells. Identification of specific genes activated by 1,25D3 has provided clues to the physiological function of the vitamin D3 pathway in the dolphin. We found that exposure of the cells to 1,25D3 upregulated transactivation of a vitamin D-sensitive promoter. cDNA microarray analysis, using a novel dolphin array, identified specific gene targets within this pathway, and real-time PCR (qPCR) confirmed the enhanced expression of select genes of interest. These transcriptional changes correlated with an increase in VDR levels. This is the first report of the presence and activation of the vitamin D3 pathway in a marine mammal, and our experimental results demonstrate a number of similarities to terrestrial animals. Conservation of this pathway in the Atlantic bottlenose dolphin is consistent with the importance of nonclassic functions of vitamin D3, such as its role in innate immunity, similar to what has been demonstrated in other mammals.