Eldecalcitol protected osteocytes against ferroptosis of D-gal-induced senescent MLO-Y4 cells and ovariectomized mice

BACKGROUND

Active vitamin D analog eldecalcitol is clinically applied in treatment of postmenopausal osteoporosis. This study aims to determine the role of eldecalcitol in the protection of osteocytes from senescence and the associated ferroptosis.

METHODS

The MLO-Y4 osteocytes were exposed to D-gal inducing senescence. The ovariectomized (OVX) mice treated with D-gal using as an aging inducer were intraperitoneally injected with eldecalcitol. The multiplexed confocal imaging, fluorescence in situ hybridization and transmission electron microscopy were applied in assessing osteocytic properties. Immunochemical staining and immunoblotting were carried out to detect abundance and expression of molecules.

RESULTS

The ablation of vitamin D receptor led to a reduction in amounts of osteocytes, a loss of dendrites, an increase in mRNA expression of SASP factors and in protein expression of senescent factors, as well as changes in mRNA expression of ferroptosis-related genes (PTGS2 & RGS4). Eldecalcitol reversed senescent phenotypes of MLO-Y4 cells shown by improving cell morphology and density, decreasing β-gal-positive cell accumulation, and down-regulating protein expression (P16, P21 & P53). Eldecalcitol reduced intracellular ROS and MDA productions, elevated JC-1 aggregates, and up-regulated expression of Nrf2 and GPX4. Eldecalcitol exhibited osteopreserve effects in D-gal-induced aging OVX mice. The confocal imaging displayed its improvement on osteocytic network organization. Eldecalcitol decreased the numbers of senescent osteocytes at tibial diaphysis by SADS assay and attenuated mRNA expression of SASP factors as well as down-regulated protein expression of senescence-related factors and restored levels of ferroptotic biomarkers in osteocytes-enriched bone fraction. It reduced 4-HNE staining area, stimulated Nrf2-positive staining, and promoted nuclear translocation of Nrf2 in osteocytes of mice as well as inhibited and promoted protein expression of 4-HNE and Nrf2, respectively, in osteocytes-enriched bone fraction.

CONCLUSIONS

The present study revealed the ameliorative effects of eldecalcitol on senescence and the associated ferroptosis of osteocytes, contributing to its preservation against osteoporosis of D-gal-induced senescent ovariectomized mice.

Vitamin D status alters genes involved in ovarian steroidogenesis in muskrat granulosa cells

This study aims to explore the relationship between altered vitamin D (VitD3) status and ovarian steroidogenesis in muskrats during the breeding and non-breeding seasons. During the breeding season, the ovaries of muskrats were observably enlarged and increased in weight, accompanied by elevated serum and ovarian VitD3 status. Vitamin D receptor (VDR), VitD3 metabolic molecules (CYP2R1, CYP27B1, and CYP24A1), and steroidogenic enzymes were immunolocalized in the ovarian cells of muskrats. The mRNA levels of VDR, CYP2R1, CYP27B1, and steroidogenic enzymes were considerably higher during the breeding season compared to the non-breeding season. RNA-seq analysis revealed a prominent enrichment of vitamin-related and ovarian steroidogenesis pathways. Furthermore, the addition of 1,25(OH)2D3 to the muskrat granulosa cells in vitro increased VDR and steroidogenic enzymes mRNA levels and enhanced the 17β-estradiol level. Overall, these findings supported that VitD3 promotes the secretion of steroid hormones, thereby affecting seasonal changes in ovarian function in the muskrats.

Molecular effects of Vitamin-D and PUFAs metabolism in skeletal muscle combating Type-II diabetes mellitus

Multiple post-receptor intracellular alterations such as impaired glucose transfer, glucose phosphorylation, decreased glucose oxidation, and glycogen production contribute to insulin resistance (IR) in skeletal muscle, manifested by diminished insulin-stimulated glucose uptake. Type-2 diabetes mellites (T2DM) has caused by IR, which is also seen in obese patients and those with metabolic syndrome. The Vitamin-D receptor (VDR) and poly unsaturated fatty acids (PUFAs) roles in skeletal muscle growth, shapes, and function for combating type-2 diabetes have been clarified throughout this research. VDR and PUFAs appears to show a variety of effects on skeletal muscle, in addition it shows a promising role on bone and mineral homeostasis. Individuals having T2DM are reported to suffer from severe muscular weakness and alterations in shape of the muscle. Several studies have investigated the effect on VDR on muscular strength and mass, which leads to Vitamin-D deficiency (VDD) in individuals, in which most commonly seen in elderly. VDR has been shown to affect skeletal cellular proliferation, intracellular calcium handling, as well as genomic activity in a variety of different ways such as muscle metabolism, insulin sensitivity, which is the major characteristic pathogenesis for IR in combating T2DM. The identified VDR gene polymorphisms are ApaI, TaqI, FokI, and BsmI that are associated with T2DM. This review collates informations on the mechanisms by which VDR activation takes place in skeletal muscles. Despite the significant breakthroughs made in recent decades, various studies show that IR affects VDR and PUFAs metabolism in skeletal muscle. Therefore, this review collates the data to show the role of VDR and PUFAs in the skeletal muscles to combat T2DM.

VDR is a potential prognostic biomarker and positively correlated with immune infiltration: a comprehensive pan-cancer analysis with experimental verification

The vitamin D receptor (VDR) is a transcription factor that mediates a variety of biological functions of 1,25-dihydroxyvitamin D3. Although there is growing evidence of cytological and animal studies supporting the suppressive role of VDR in cancers, the conclusion is still controversial in human cancers and no systematic pan-cancer analysis of VDR is available. We explored the relationships between VDR expression and prognosis, immune infiltration, tumor microenvironment or gene set enrichment analysis (GSEA) in 33 types of human cancers based on multiple public databases and R software. Meanwhile, the expression and role of VDR were experimentally validated in papillary thyroid cancer (PTC). VDR expression decreased in 8 types and increased in 12 types of cancer compared to normal tissues. Increased expression of VDR was associated with either good or poor prognosis in 13 cancer types. VDR expression was positively correlated with the infiltration of cancer-associated fibroblasts, macrophages, or neutrophils in 20, 12 and 10 cancer types respectively and this correlation was experimentally validated in PTC. Increased VDR expression was associated with increased percentage of stromal or immune components in tumor microenvironment (TME) in 24 cancer types. VDR positively and negatively correlated genes were enriched in immune cell function and energy metabolism pathways respectively in the top 9 highly lethal tumors. Additionally, VDR expression was increased in PTC and inhibited cell proliferation and migration. In conclusion, VDR is a potential prognostic biomarker and positively correlated with immune infiltration as well as stromal or immune components in TME in multiple human cancers.

Delving the vitamin D receptor variation and expression profiles in the context of type 2 diabetes among families

BACKGROUND

Vitamin D is essential for insulin secretion and sensitivity. Consequently, its inadequacy is linked to higher insulin resistance and Type 2 Diabetes (T2D). The Vitamin D receptor (VDR) gene is one potential candidate for T2D, and multiple polymorphisms in VDR have been examined in various populations, but no conclusive answers have been provided.

OBJECTIVES

This study was designed to evaluate the susceptibility of VDR gene polymorphism and its expression in diabetic families in Pakistan.

METHODOLOGY

In this family-based study, twenty diabetic families with a positive family history of T2D and at least three T2D patients were recruited from outpatient clinics and public hospitals. The current study comprised 143 individuals with 55 affected and 88 unaffected individuals. Blood samples of the selected families were collected. DNA was extracted from the collected samples and the PCR-RFLP method was followed to identify the genotyping and RT-qPCR for expression. Phenotypic and genotypic pedigrees of the families were developed by the progeny online tool. The association values of SNPs were determined by TDT and DFAM analysis implemented on Plink software.

RESULTS

The results explained a significant familial aggregation among phenotypic characters including Age, Gender, BMI (body mass index), age of disease diagnosis, disease duration, and blood pressure in the probands, affected FDRs (First Degree Relatives) and affected SDRs (Second Degree Relatives). A significant association of rs731236 C/T (OR = 1.522), rs2228570 C/T (OR = 1.327) with p < 0.05. Whereas, for rs1544410 G/A (OR = 0.9706) and rs7975232 T/G (OR = 0.7368) no considerable association evidence was seen (p > 0.05) in families. The mRNA expression of VDR increased threefold (p = 0.0204) in patients compared to controls. Variation-based expression analysis exhibited that the rs2228570 genotype influences the expression.

CONCLUSION

A linkage was found among the FDRs with probands. Variation in the gene VDR at loci rs731236 and rs2228570 was associated with familial T2D. However further research is required to explore more genetic factors that could influence T2D risks in families.

Nuclear localization signal in nuclear receptor VDR facilitates the mitotic genome bookmarking by involving distinct amino acid residues

Mitotic genome-bookmarking preserves epigenetic information, re-establishing progenitor's gene expression profile through transcription factors, chromatin remodelers, and histone modifiers, thereby regulating cell fate and lineage commitment post-mitotically in progeny cells. Our recent study revealed that the constitutive association of VDR with mitotic chromatin involves its DNA-binding domain. However, amino acid residues in this domain, crucial for genome bookmarking, remain elusive. This study demonstrates that nuclear localization signal (NLS) residues between 49 and 55 amino acids in VDR are essential for receptor-chromatin interaction during mitosis. Furthermore, it is revealed that both bipartite nature of VDR-NLS region and N-terminally located positively charged arginine residues are critical for its 'genome-bookmarking' property. Since mitotic chromatin association of heterodimeric partner RXR depends on VDR-chromatin association, interventions in VDR binding also abort RXR-chromatin interaction. Overall, this study documents the mechanistic details underlying VDR-chromatin interactions in genome-bookmarking behavior, potentially aiding in comprehending VDR-mediated diseases attributed to certain SNPs.

VDR promotes pancreatic cancer progression in vivo by activating CCL20-mediated M2 polarization of tumor associated macrophage

BACKGROUND

Activation of VDR pathway was a promising anti-tumor therapy strategy. However, numerous clinical studies have demonstrated the effect of activating VDR is limited, which indicates that VDR plays a complex role in vivos.

METHODS

We analyzed the TCGA database to examine the association between VDR expression and immune cell infiltration in pancreatic adenocarcinoma (PAAD). Western blot, ELISA, ChIP, and dual-luciferase reporter assays were performed to determine the mechanism of VDR regulating CCL20. Migration assay and immunofluorescence were used to investigate the role of CCL20 in M2 macrophage polarization and recruitment. We employed multiplexed immunohistochemical staining and mouse models to validate the correlation of VDR on macrophages infiltration in PAAD. Flow cytometry analysis of M2/M1 ratio in subcutaneous graft tumors.

RESULTS

VDR is extensively expressed in PAAD, and patients with elevated VDR levels exhibited a significantly reduced overall survival. VDR expression in PAAD tissues was associated with increased M2 macrophages infiltration. PAAD cells overexpressing VDR promote macrophages polarization towards M2 phenotype and recruitment in vitro and vivo. Mechanistically, VDR binds to the CCL20 promoter and up-regulates its transcription. The effects of polarization and recruitment on macrophages can be rescued by blocking CCL20. Finally, the relationship between VDR and M2 macrophages infiltration was evaluated using clinical cohort and subcutaneous graft tumors. A positive correlation was demonstrated between VDR/CCL20/CD163 in PAAD tissues and mouse models.

CONCLUSION

High expression of VDR in PAAD promotes M2 macrophage polarization and recruitment through the secretion of CCL20, which activates tumor progression. This finding suggests that the combination of anti-macrophage therapy may improve the efficacy of VDR activation therapy in PAAD.

Design, synthesis, and biological activity of D-bishomo-1α,25-dihydroxyvitamin D3 analogs and their crystal structures with the vitamin D nuclear receptor

The biologically active metabolite of vitamin D3 - calcitriol - is a hormone involved in the regulation of calcium-phosphate homeostasis, immunological processes and cell differentiation, being therefore essential for the proper functioning of the human body. This suggests many applications of this steroid in the treatment of diseases such as rickets, psoriasis and some cancers. Unfortunately, using therapeutic doses of calcitriol is associated with high concentrations of this compound which causes hypercalcemia. For this reason, new calcitriol analogs are constantly sought, devoid of calcemic effects but maintaining its beneficial properties. In this study, we present the synthesis of vitamin D derivatives characterized by an enlarged (seven-membered) ring D. Preparation of the designed vitamin D compounds required separate syntheses of crucial building blocks (C/D-rings fragments with side chain and rings A) which were combined by different methods, including Wittig-Horner reaction and Suzuki coupling. Biological activities of the target vitamin D analogs were assessed both in vitro and in vivo, demonstrating their significant potency compared to the natural hormone. Furthermore, the successful crystallization of these compounds with the vitamin D receptor (VDR) enabled us to investigate additional molecular interactions with this protein.

The role of interaction between vitamin D and VDR FokI gene polymorphism (rs2228570) in sleep quality of adults

To evaluate association of vitamin D with sleep quality in adults and the influence of VDR-gene polymorphism FokI (rs2228570;A > G). Cross-sectional population-based study in adults, conducted in Brazil. The outcome was sleep-quality, evaluated by the Pittsburgh Sleep Quality Index. Vitamin D was determined by indirect electrochemiluminescence and classified as deficiency (VDD), 25(OH)D < 20 ng/mL in a healthy population or 25(OH)D < 30 ng/mL for groups at risk for VDD. FokI polymorphism in the VDR-gene was genotyped by qPCR and classified as homozygous wild (FF or AA), heterozygous (Ff or AG), or homozygous mutant (ff or GG). Multivariate logistic analysis was used to estimate the association between vitamin D and FokI polymorphism with sleep-quality. In a total of 1674 individuals evaluated, 53.6% had poor-sleep-quality, 31.5% had VDD, and the genotype frequency of the FokI polymorphism was 9.9% FF, 44.6% Ff, and 45.5% ff. In multivariate analysis, individuals with VDD had 1.51 times the chance of poor-sleep-quality, and individuals with the ff genotype had 1.49 times the chance of poor-sleep-quality (OR:1.49;95%CI:1.05-2.12) when compared to individuals with the FF or Ff genotype. In the combined analysis, individuals with VDD and ff genotype had more chance of poor-sleep-quality than individuals with sufficient vitamin D and genotype Ff or FF (OR:2.19;95%CI:1.27-3.76). Our data suggest that VDD and VDR FokI gene polymorphism are associated with poor-sleep-quality, and combining the two factors increases the chance of poor-sleep-quality compared to separate groups.

Vitamin D status, vitamin D receptor polymorphisms, and risk of type 2 diabetes: A prospective cohort study

CONTEXT

Vitamin D status has been associated with risk of type 2 diabetes (T2D), but evidence is scarce regarding whether such relation differs by glycemic status.

OBJECTIVE

To prospectively investigate the association between serum 25-hydroxyvitamin D [25(OH)D] and risk of incident T2D across the glycemic spectrum and the modification effect of genetic variants in vitamin D receptor (VDR).

METHODS

This prospective study included 379,699 participants without T2D at baseline from the UK Biobank. Analyses were performed according to glycemic status and HbA1c levels. Cox proportional hazard models were used to calculate hazard ratios (HRs) and 95% CIs.

RESULTS

During a median of 14.1 years of follow-up, 6,315 participants with normoglycemia and 9,085 prediabetes patients developed T2D. Compared to individuals with 25(OH)D <25 nmol/L, the multivariable-adjusted hazard ratios (95% CIs) of incident T2D for those with 25(OH)D ≥75 nmol/L was 0.62 (0.56, 0.70) among the normoglycemia and 0.64 (0.58, 0.70) among the prediabetes. A significant interaction was observed between 25(OH)D and VDR polymorphisms among participants with prediabetes (Pinteraction=0.017), whereby the reduced HR of T2D associated with higher 25(OH)D was more prominent in those carrying T allele of rs1544410. Triglycerides levels mediated 26% and 34% of the association between serum 25(OH)D and incident T2D among participants with normoglycemia and prediabetes.

CONCLUSIONS

Higher serum 25(OH)D concentrations were associated with lower T2D risk across the glycemic spectrum below the threshold for diabetes, and the relations in prediabetes were modified by VDR polymorphisms. Improving lipid profile, mainly triglycerides, accounted for part of the favorable associations.

Relationship with Body Composition, Calcium, Magnesium and Phosphorous

INTRODUCTION

A generalized risk of vitamin D deficiency exists worldwide affecting also professional and elite athletes. This study assesses the evolution of vitamin D status and vitamin D receptor (VDR) gene expression and their relationship with body composition, calcium (Ca), magnesium (Mg) and phosphorous (P) among professional handball athletes during a competitive period.

METHODS

A total of 26 male subjects were recruited: 13 professional handball athletes and 13 non-athlete controls. An observational follow-up study was conducted in 2 time points over a 16-week period. Nutritional intake, body composition, and routinary biochemical parameters were measured via 24-hours recall, bioimpedance and enzyme immunoassay, respectively. Ca and Mg were measured by flame atomic absorption spectrophotometry and P was determined with the colorimetric method of Fiske-Subbarow. 25-hydroxyvitamin-D (25(OH)D) levels and its forms (i.e., 25(OH)D3 and 25(OH)D2) were measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS), whereas VDR gene expression was measured by quantitative real time-polymerase chain reaction (qRT-PCR).

RESULTS

A total of 54% of the athletes showed deficient vitamin D status. Moreover, a prevalence of insufficient vitamin D status in handball players affected 46% at baseline, reaching 61% after 16 weeks. Vitamin D showed no evolution during the competitive period and no differences between groups were observed (all p ≥ 0.05). Handball players increased the VDR expression, enhanced body composition, Ca and Mg levels at 16-weeks follow-up (all p < 0.05). VDR gene expression was positively related with body mass and body mass index at follow-up in athletes (all p ≤ 0.038; r ≥ 0.579) and with Ca at baseline in controls (p = 0.026; r = 0.648). Finally, 25(OH)D2 form was directly associated with P in athletes at 16 weeks of study (p = 0.034; r = 0.588).

CONCLUSION

Players of indoor team sports such as handball would be a population at risk of vitamin D deficiency. The 16-weeks competition improved VDR gene expression, body composition, Ca and Mg levels. The associations observed between VDR gene expression and the variables of the study evidenced the importance of this receptor as a marker involved in health status in handball athletes despite vitamin D - although in a deficient status -, Ca, Mg and P showed no remarkable changes during the competition period.

Vitamin D and ischemic stroke - Association, mechanisms, and therapeutics

Confronting the rising tide of ischemic stroke and its associated mortality and morbidity with ageing, prevention and acute management of ischemic stroke is of paramount importance. Mounting observational studies have established a non-linear association of vitamin D status with cardiovascular diseases, including ischemic stroke. Paradoxically, current clinical trials fail to demonstrate the cardiovascular benefits of vitamin D supplementation. We aim to update recent clinical and experimental findings on the role of vitamin D in the disease course of ischemic stroke, from its onset, progression, recovery, to recurrence, and the established and alternative possible pathophysiological mechanisms. This review justifies the necessities to address stroke etiological subtypes and focus on vitamin D-deficient subjects for investigating the potential of vitamin D supplementation as a preventive and therapeutic approach for ischemic stroke. Well-powered clinical trials are warranted to determine the efficacy, safety, timing, target individuals, optimal dosages, and target 25OHD concentrations of vitamin D supplementation in the prevention and treatment of ischemic stroke.

Serum 25-Hydroxyvitamin D, Vitamin D Receptor, and Vitamin-D-Binding Protein Gene Polymorphisms and Risk of Dementia Among Older Adults With Prediabetes

BACKGROUND

The association between vitamin D and dementia risk in those with prediabetes remains uncertain. We aimed to evaluate the association of serum 25-hydroxyvitamin D (25OHD) with incident dementia among older adults with prediabetes, and examine whether apolipoprotein E (APOE) genotypes, vitamin D receptor (VDR), and vitamin-D-binding protein (VDBP) gene polymorphisms may modify this association.

METHODS

A total of 34 237 participants aged ≥60 with prediabetes (HbA1c <6.5% and ≥5.7%) and without dementia at baseline were included from the UK Biobank. Serum 25-hydroxyvitamin D (25OHD) was measured using chemiluminescent immunoassay method. The primary outcome was incident all-cause dementia. Secondary outcomes included incident Alzheimer's disease (AD) and vascular dementia, respectively. The VDR and VDBP gene polymorphisms included single nucleotide polymorphisms of rs7975232, rs1544410, rs2228570, rs731236, and rs7041, rs4588, respectively.

RESULTS

During a median follow-up of 11.8 years, 941 (2.7%) participants developed incident all-cause dementia. Overall, serum 25OHD was inversely associated with all-cause dementia (per standard deviation increment, adjusted hazard ratio: 0.82; 95% confidence interval: 0.75, 0.89). Similar trends were found for incident AD and vascular dementia. Furthermore, there was a stronger inverse relationship between serum 25OHD and all-cause dementia among VDR rs7975232 C allele noncarriers (p-interaction < 0.05). However, APOE Ɛ4, other VDR, and VDBP gene polymorphisms did not significantly modify the relation of serum 25OHD with incident all-cause dementia (all p-interactions >.05).

CONCLUSIONS

There was an inverse association between serum 25OHD and incident dementia among older adults with prediabetes, especially in VDR rs7975232 AA allele carriers.

Association between vitamin D receptor gene variants and neonatal sepsis: A systematic review and meta-analysis

The objective of this systematic review and meta-analysis was elucidating the association of VDR SNPs (FokI, TaqI, BsmI, BgII, and ApaI) with neonatal sepsis. Literature search was performed to retrieve records published until August 2nd, 2023 (PROSPERO registration: CRD42023451355). Meta-analysis was carried out to determine the pooled estimates for Odds Ratio (OR). A total of four studies were included with 500 neonates (250 sepsis cases and 250 healthy controls). There was an association observed between TaqI SNP with neonatal sepsis for CT vs. CC+TT (OR=1.95) and TT vs CT+CC (OR=0.40). Moreover, the pooled estimates also suggested that CC vs. CT+TT (OR= 0.37) and C vs. T (OR=0.66) of FokI SNP were significantly associated with neonatal sepsis. SNP of BgII was found to be significantly associated with neonatal sepsis, but only reported in a single study.

Exercise-induced vitamin D receptor and androgen receptor mediate inhibition of IL-6 and STAT3 in muscle

Background

Skeletal muscle produces interleukin-6 (IL-6) during exercise as a myokine. Although IL-6 is required for skeletal muscle regeneration, its action increases the expression of myostatin and other proteins involved in muscle atrophy, resulting in skeletal muscle atrophy. In this study, we clarified the effects exercise-induced vitamin D receptor (VDR) and androgen receptor (AR) expression on IL-6 and signal transducer and activator of transcription 3 (STAT3) in vivo and in vitro.

Method

C2C12 myotubes were subjected to electric pulse stimulation (EPS) in vitro. To evaluate VDR and AR function, a VDR/AR agonist and antagonist were administered before EPS to C2C12 myotubes. C57BL6 mice underwent 4 weeks of exercise. The expression levels of proteolytic-associated genes, including CCAAT/enhancer-binding protein delta (C/EBPδ) and myostatin, were measured by quantitative real-time polymerase chain reaction, and phosphorylated and total STAT3 levels were measured by Western blot analysis.

Result

The expression of VDR and AR mRNA was induced following EPS in C2C12 myotubes. IL-6 mRNA expression was also increased with a peak at 6 h after EPS and p-STAT3/STAT3 ratio reciprocally decreased. Although VDR/AR agonist administration decreased IL-6 mRNA expression and p-STAT3/STAT3 ratio, these two endpoints increased after treatment with VDR/AR antagonist, respectively. Exercise in mice also increased the expression of VDR/AR and IL-6 mRNA and decreased p-STAT3/STAT3 ratio.

Conclusion

Exercise-induced VDR and AR expression results in the suppression of IL-6 mRNA and STAT3 phosphorylation in skeletal muscle.

Association between Vitamin D Receptor Polymorphism and Susceptibility to Oral Lichen Planus and Oral Squamous Cell Carcinoma

Introduction

Oral squamous cell carcinomas (OSCC) comprise 90-95% of oral cancers. Early diagnosis improved the survival rate of OSCC patients to 80-90%. Oral lichen planus (OLP) is a chorionic inflammatory disease with malignancy potential. The vitamin D receptor (VDR) plays a critical role in the pathogenesis of oral cancer. This study aimed to determine the association between VDR rs7975232 (Apa I) polymorphism and potential susceptibility to OLP and OSCC risks.

Materials and Methods

In this prospective case-control study, a total of 120 blood samples were obtained from OSCC patients (n=29), OLP (n=50), and controls (n=40). VDR rs7975232 polymorphism was studied using the Polymerase Chain Reaction Restriction Fragment Length Polymorphism (PCR-RFLP) method. Statistical analysis was performed with SPSS Version 23 software. Data were expressed as means ± standard deviation (SD). Age, sex, allelic frequency, and genotyping were compared using the chi-square test. A p-value of less than 0.05 was regarded as statistically significant. The disease risk was estimated by Odds ratio (OR) with a 95% confidence interval.

Results

A significant age difference was observed between the controls and the OSCC group (p=0.001). A significant difference was observed in Aa and aa genotypes compared with AA between OSCCs and controls. Moreover, dominant (p<0.001), additive (p<0.001), and allelic (p=0.001) models were different between groups.

Conclusion

There was a positive association between rs7975232 VDR polymorphism and susceptibility to OSCC. More experimental evidence must reveal the possible association between rs7975232 and the risk of OLP in a larger cohort.

Sequential administration of paricalcitol followed by IL-17 blockade for progressive refractory IgA nephropathy patients

There is no established treatment for progressive IgA nephropathy refractory to steroids and immunosuppressant drugs (r-IgAN). Interleukin 17 (IL-17) blockade has garnered interest in immune-mediated diseases involving the gut-kidney axis. However, single IL-17A inhibition induced paradoxical effects in patients with Crohn's disease and some cases of de novo glomerulonephritis, possibly due to the complete Th1 cell response, along with the concomitant downregulation of regulatory T cells (Tregs). Seven r-IgAN patients were treated with at least six months of oral paricalcitol, followed by the addition of subcutaneous anti-IL-17A (secukinumab). After a mean follow-up of 28 months, proteinuria decreased by 71% (95% CI: 56-87), P < 0.001. One patient started dialysis, while the annual eGFR decline in the remaining patients [mean (95% CI)] was reduced by 4.9 mL/min/1.73 m2 (95% CI: 0.1-9.7), P = 0.046. Circulating Th1, Th17, and Treg cells remained stable, but Th2 cells decreased, modifying the Th1/Th2 ratio. Intriguingly, accumulation of circulating Th17.1 cells was observed. This novel sequential therapy appears to optimize renal advantages in patients with r-IgAN and elicit alterations in potentially pathogenic T helper cells.

Vitamin D3 improves iminodipropionitrile-induced tic-like behavior in rats through regulation of GDNF/c-Ret signaling activity

Children with chronic tic disorders (CTD), including Tourette syndrome (TS), have significantly reduced serum 25-hydroxyvitamin D [25(OH)D]. While vitamin D3 supplementation (VDS) may reduce tic symptoms in these children, its mechanism is unclear. The study aim was to investigate the effects and mechanisms of vitamin D deficiency (VDD) and VDS on TS model behavior. Forty 5-week-old male Sprague-Dawley rats were randomly divided into (n = 10 each): control, TS model, TS model with VDD (TS + VDD), or TS model with VDS (TS + VDS; two intramuscular injections of 20,000 IU/200 g) groups. The VDD model was diet-induced (0 IU vitamin D/kg); the TS model was iminodipropionitrile (IDPN)-induced. All groups were tested for behavior, serum and striatal 25(OH)D and dopamine (DA), mRNA expressions of vitamin D receptor (VDR), glial cell line-derived neurotrophic factor (GDNF), protooncogene tyrosine-protein kinase receptor Ret (c-Ret), and DA D1 (DRD1) and D2 (DRD2) receptor genes in the striatum. TS + VDD had higher behavior activity scores throughout, and higher total behavior score at day 21 compared with TS model. In contrast, day 21 TS + VDS stereotyped behavior scores and total scores were lower than TS model. The serum 25(OH)D in TS + VDD was < 20 ng/mL, and lower than control. Striatal DA of TS was lower than control. Compared with TS model, striatal DA of TS + VDD was lower, while in TS + VDS it was higher than TS model. Furthermore, mRNA expression of VDR, GDNF, and c-Ret genes decreased in TS model, and GDNF expression decreased more in TS + VDD, while TS + VDS had higher GDNF and c-Ret expressions. VDD aggravates, and VDS ameliorates tic-like behavior in an IDPN-induced model. VDS may upregulate GDNF/c-Ret signaling activity through VDR, reversing the striatal DA decrease and alleviating tic-like behavior.

Tremendous Fidelity of Vitamin D3 in Age-related Neurological Disorders

Vitamin D3 (VD) is a secosteroid hormone and shows a pleiotropic effect in brain-related disorders where it regulates redox imbalance, inflammation, apoptosis, energy production, and growth factor synthesis. Vitamin D3's active metabolic form, 1,25-dihydroxy Vitamin D3 (1,25(OH)2D3 or calcitriol), is a known regulator of several genes involved in neuroplasticity, neuroprotection, neurotropism, and neuroinflammation. Multiple studies suggest that VD deficiency can be proposed as a risk factor for the development of several age-related neurological disorders. The evidence for low serum levels of 25-hydroxy Vitamin D3 (25(OH)D3 or calcidiol), the major circulating form of VD, is associated with an increased risk of Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), dementia, and cognitive impairment. Despite decades of evidence on low VD association with neurological disorders, the precise molecular mechanism behind its beneficial effect remains controversial. Here, we will be delving into the neurobiological importance of VD and discuss its benefits in different neuropsychiatric disorders. The focus will be on AD, PD, and HD as they share some common clinical, pathological, and epidemiological features. The central focus will be on the different attributes of VD in the aspect of its anti-oxidative, anti-inflammatory, anti-apoptotic, anti-cholinesterase activity, and psychotropic effect in different neurodegenerative diseases.

Combination of vitamin D3 and fructooligosaccharides upregulates colonic vitamin D receptor in C57BL/6J mice and affects anxiety-related behavior in a sex-specific manner

Depression and anxiety disorders are among the most common mental health disorders that affect US adults today, frequently related to vitamin D (VD) insufficiency. Along with VD, growing evidence suggests gut microbiota likely play a role in neuropsychiatric disorders. Here, we investigated if modulation of gut microbiota would disrupt host VD status and promote behaviors related to depression and anxiety in adult mice. Six-week-old male and female C57BL/6J mice (n = 10/mice/group) were randomly assigned to receive (1) control diet (CTR), control diet treated with antibiotics (AB), control diet with total 5000 IU of VD (VD), VD treated with antibiotics (VD + AB), VD supplemented with 5% w/w fructooligosaccharides (FOS; VF), and VF diet treated with antibiotics (VF + AB), respectively, for 8 weeks. Our study demonstrated that VD status was not affected by antibiotic regimen. VD alone ameliorates anxiety-related behavior in female mice, and that combination with FOS (i.e., VF) did not further improve the outcome. Male mice, in contrast, exhibit greater anxiety with VF, but not VD, when compared with CTR mice. Colonic VD receptor was elevated in VF-treated mice in both sexes, compared with CTR, which was positively correlated to colonic TPH1, a rate-limiting enzyme for serotonin synthesis. Taken together, our data indicate that the effect of VF on anxiety-related behavior is sex-specific, which may partially be attributed to the activation of colonic VD signaling and subsequent serotonin synthesis. The synergistic or additive effect of VD and FOS on mood disorders remained to be investigated.

Vitamin D receptor expression in hydatidiform mole and gestational trophoblastic neoplasia: A cross-sectional study

Objective

Vitamin D receptor (VDR) exerts anti-cancer properties in a variety of cancers. The purpose of this study was to investigate the expression of VDR in patients with hydatidiform mole (HM) and gestational trophoblastic neoplasia (GTN).

Methods

This is a cross-sectional study involved 61 specimens of HM (n = 37, 60.7%) and GTN (n = 24, 39.3%) was collected from the biopsy. An immunohistochemistry was used to asses the VDR expression. Student's t-test and Mann-Whitney test were used to compare the expression of VDR, including VDR staining intensity, VDR distribution, and histoscore, between HM and GTN tissue specimens.

Results

No significant differences in age and parity were noted between patients with HM or GTN (p > 0.05). The VDR staining intensity of GTN tissue specimens was significantly lower than that of HM tissue specimens (2.3 ± 0.8 vs. 2.8 ± 0.5, p = 0.008). In addition, the histoscore for GTN tissues was significantly lower than that for HM tissues (7.3 ± 3.2 vs. 9.4 ± 28, p = 0.016). However, no significant differences in VDR distribution between GTN and HM tissues were observed (3.3 ± 0.8 vs. 3.3 ± 1.0, p = 0.525).

Conclusion

Low VDR expression is associated with GTN, whereas high VDR expression is associated with HM, suggesting that the expression of VDR may regulate the severity of gestational trophoblastic disease.

The impact of age on vitamin D receptor expression, vitamin D metabolism and cytokine production in ex vivo Rhodococcus equi infection of equine alveolar macrophages

Rhodococcus equi (R. equi), a pneumonia-causing intracellular bacterium, results in significant morbidity and mortality in young foals, while healthy adult horses rarely develop disease. Survival and replication within alveolar macrophages (AMφ) are the hallmarks of R. equi's pathogenicity. The vitamin D receptor (VDR) and its ligand, the active vitamin D metabolite 1,25(OH)2D, are important in immune responses to intracellular bacteria. The vitamin D/VDR pathway regulates the downstream production of cytokines in infected human AMφ. The immunomodulatory role of the vitamin D/VDR pathway in equine leukocytes is unknown. The objective of the current study was to determine the impact of R. equi infection and age on synthesis of 1,25(OH)2D, VDR expression, and cytokine production in an ex vivo model of R. equi infection in equine AMφ. AMφ were collected from ten healthy foals at 2-, 4- and 8-weeks old and from nine healthy adult horses once via bronchoalveolar lavage. AMφ were mock infected (CONTROL) or infected with a virulent laboratory strain of R. equi for 7 days (INFECTED). VDR expression was determined via RT-qPCR from cell lysates. 1,25(OH)2D and cytokines were measured in cell supernatant by immunoassays. VDR expression was impacted by age (P = 0.001) with higher expression in AMφ from 8-week-old foals than from 2-week-old foals and adults. There was no significant effect of infection in foal AMφ, but in adults, relative VDR expression was significantly lower in INFECTED AMφ compared to CONTROL AMφ (P = 0.002). There was no effect of age or infection on 1,25(OH)2D concentration (P > 0.37). Mean TNFα production was significantly higher from INFECTED compared to CONTROL AMφ from 4- and 8-week-old foals and adults (P < 0.005). Mean IFNγ production was significantly higher from AMφ from foals at 8-weeks-old compared to 2-weeks-old (P = 0.013) and higher from INFECTED AMφ than from CONTROL AMφ in foals at 4-weeks-old and in adults (P < 0.027). The proportion of samples producing IL-1β and IL-10 was also significantly higher from INFECTED compared to CONTROL AMφ isolated from 4-week-old foals (P < 0.008). Similarly, in adult samples, IL-17 was produced from a greater proportion of INFECTED compared to CONTROL samples (P = 0.031). These data document age-associated changes in VDR expression and cytokine production in equine AMφ in response to R. equi infection. This preliminary investigation supports the need for further research to fully elucidate if the vitamin D pathway has an immunomodulatory role in the horse.

MicroRNA-125b mediates Interferon-γ-induced downregulation of the vitamin D receptor in systemic lupus erythematosus

BACKGROUND

The inflammatory factor interferon (IFN)-γ is related to the occurrence and development of systemic lupus erythematosus (SLE). The vitamin D receptor (VDR) has an anti-inflammatory effect and its downregulation is involved in the onset of SLE. Our previous studies have confirmed that the expression of VDR in SLE peripheral blood mononuclear cells (PBMCs) is downregulated, which is negatively correlated with disease activity and inflammation. However, the mechanism underlying VDR downregulation in SLE is unknown.

METHODS

Based on the results of computer simulation analysis, the expression of VDR and four microRNAs (miR-17-3p, miR-34a, miR-346, and miR-125b) in SLE PBMC cells was analyzed under proinflammatory cytokine IFN‑γ treatment, and miR-125b was identified as the target miRNA. The relationship between IFN‑γ, miR-125b, and VDR was further assessed in THP‑1 cells.

RESULTS

We showed that IFN‑γ inhibited the expression of VDR and miR-125b. Further study revealed that VDR mRNA was positively correlated with miR-125b in THP‑1 cells after IFN‑γ intervention. After transfection of miR-125b mimic or inhibitor, the expression of VDR in the miR-125b inhibitor group was lower than in the control group and miR-125b mimic group, while expression in the control group was lower than in miR-125b mimic group. Transfection of miR-125b inhibitor into THP‑1 cells could further promote the ability of IFN‑γ to inhibit VDR.

CONCLUSION

The decrease in VDR expression promotes development of inflammation and SLE. These data suggest that miR-125b may mediate inflammatory factor IFN-γ-induced downregulation of VDR in the pathogenesis of SLE.

The effect of BsmI (rs1544410) single nucleotide polymorphism of vitamin D receptor (VDR) on insulin resistance in healthy children and adolescents: a cross-sectional study

The increasing prevalence of metabolic syndrome, type 2 diabetes, and insulin resistance are driven by complex interactions between genetic and environmental factors. One of the single nucleotide polymorphisms (SNPs) in the VDR gene associated with vitamin D levels is the rs1544410 SNP. This study examined the association of the rs1544410 polymorphism with insulin resistance to predict and screen for possible association with type 2 diabetes and target these individuals for appropriate treatment. This cross-sectional study examined 270 children and adolescents aged 9 to 18 years. Anthropometric and biochemical parameters were determined. Insulin resistance/sensitivity was determined using Quicki, HOMA-IR, MacAuley, Revised MacAuley, Bennetts, FIRI and insulin-to-glucose ratio. The BsmI single nucleotide polymorphism (rs1544410) was determined using the PCR-RFLP method after extracting DNA from peripheral blood collected from fasted subjects, and the resulting data were analyzed using SPSS software and statistical tests.According to linear regression analysis, a significant difference was found in Insulin to glucose ratio, FIRI and HOMA-IR indices between Bb / bb and BB genotypes and it was observed that individuals with BB genotype polymorphism of BsmI vitamin D receptor gene, after Adjustment of age, sex, BMI are at greater risk for insulin resistance and type 2 diabetes.This study demonstrated that those with the BB genotype of VDR BsmI polymorphism were at higher risk for insulin resistance and developing type 2 DM.

The impact of circulating 25-hydroxyvitamin D and vitamin D receptor variation on leukemia-lymphoma outcome: Molecular and cytogenetic study

Vitamin D (VD) potentially has a crucial function in the development of cancerous cells. This study aims to detect the role of vitamin D concentration and its receptor polymorphisms as possible prognostic biomarkers in patients with leukemia/lymphoma and further will attempt to detect the presence of the Philadelphia chromosome abnormality in chronic myeloid leukemia (CML). Seventy-five patients, in addition to 50 healthy individuals were included. Three single nucleotide polymorphisms of the vitamin D receptor (FokI, Tru91, and ApaI) were identified via Polymerase Chain Reaction- Fragment Length Polymorphism (PCR-RFLP). Sanger sequencing and karyotyping for all patients has been undertaken. Out of 75 patients, 69 (92.0%) were vitamin D deficient. The homozygous genotype TT of FokI is the most commonly found in non-Hodgkin's lymphoma, while the heterozygous CT is observed markedly in CML, chronic lymphoid leukemia, and Hodgkin's lymphoma. The AC and CC genotypes of ApaI are more frequent in patients with CML, while the AC genotype is the most common in HL. In Tru9I, the GG genotype has a wider distribution in individuals diagnosed with leukemia. The PCR-RFLP and Sanger sequencing techniques together confirmed significant genotype respectively. The Philadelphia chromosome, t (9;22) was found in five (17%) cases with CML. There is a marked relationship between FokI, ApaI, and Tru91 polymorphisms and the chance of developing leukemia. In lymphoma, a significant connection between the polymorphisms of FokI and ApaI is frequently detected. Cytogenetic and molecular testing are essential for detection of CML and monitoring therapy response.

Association between vitamin D receptor gene FokI polymorphism and mortality in patients with sepsis

BACKGROUND

Sepsis is life-threatening organ dysfunction as a result of the host's dysregulated immune response to infection. The vitamin D receptor (VDR) gene FokI polymorphism influences immune cell behavior. In the present study, we aimed to investigate the association between VDR FokI polymorphism and mortality in sepsis and non-sepsis patients in the intensive care unit (ICU).

METHODS AND RESULTS

This is a prospective observational study involving 96 sepsis and 96 non-sepsis patients admitted to the Ege University ICU. VDR FokI polymorphisms were investigated, as well as the relationship between the identified polymorphisms and mortality.  In-hospital mortality was 27.1% in the sepsis group and 8.33% in the non-sepsis group (p = 0.001). The frequencies of VDR FokI TT, TC, and CC genotypes were 8 (8.33%), 48 (50.0%), and 40 (41.7%) in the sepsis group, and 11 (11.5%), 42 (43.8%), and 43 (44.8%) in the non-sepsis group, respectively (p = 0.612). In the sepsis group, the frequencies of Fokl TT, TC, and CC genotypes did not differ significantly between survivors and non-survivors. However, homozygous C allele carriers had lower overall mortality (p = 0.047).

CONCLUSION

The VDR FokI polymorphism, particularly the CC genotype, appears to be associated with lower mortality in ICU patients.

Eldecalcitol prevents muscle loss and osteoporosis in disuse muscle atrophy via NF-κB signaling in mice

We investigated the effect of eldecalcitol on disuse muscle atrophy. C57BL/6J male mice aged 6 weeks were randomly assigned to control, tail suspension (TS), and TS-eldecalcitol-treated groups and were injected intraperitoneally twice a week with either vehicle (control and TS) or eldecalcitol at 3.5 or 5 ng for 3 weeks. Grip strength and muscle weights of the gastrocnemius (GAS), tibialis anterior (TA), and soleus (SOL) were determined. Oxidative stress was evaluated by malondialdehyde, superoxide dismutase, glutathione peroxidase, and catalase. Bone microarchitecture was analyzed using microcomputed tomography. The effect of eldecalcitol on C2C12 myoblasts was analyzed by measuring myofibrillar protein MHC and the atrophy markers Atrogin-1 and MuRF-1 using immunofluorescence. The influence of eldecalcitol on NF-κB signaling pathway and vitamin D receptor (VDR) was assessed through immunofluorescence, (co)-immunoprecipitation, and VDR knockdown studies. Eldecalcitol increased grip strength (P < 0.01) and restored muscle loss in GAS, TA, and SOL (P < 0.05 to P < 0.001) induced by TS. An improvement was noted in bone mineral density and bone architecture in the eldecalcitol group. The impaired oxidative defense system was restored by eldecalcitol (P < 0.05 to P < 0.01 vs. TS). Eldecalcitol (10 nM) significantly inhibited the expression of MuRF-1 (P < 0.001) and Atrogin-1 (P < 0.01), increased the diameter of myotubes (P < 0.05), inhibited the expression of P65 and P52 components of NF-κB and P65 nuclear location, thereby inhibiting NF-κB signaling. Eldecalcitol promoted VDR binding to P65 and P52. VDR signaling is required for eldecalcitol-mediated anti-atrophy effects. In conclusion, eldecalcitol exerted its beneficial effects on disuse-induced muscle atrophy via NF-κB inhibition.

VDR gene ApaI polymorphism and risk of postmenopausal osteoporosis: a meta-analysis from 22 studies

OBJECTIVE

The ApaI polymorphism (G > T, rs7975232) of the vitamin D receptor (VDR) gene in the risk of postmenopausal osteoporosis has been widely researched, and the results have yielded conflicts. Therefore, we performed an updated pooled analysis to comprehensively assess the association between VDR ApaI polymorphism and postmenopausal osteoporosis risk.

METHODS

We searched eligible studies about ApaI polymorphism and osteoporosis through the PubMed, Embase, CNKI and Wanfang databases; case-control studies containing available genotype frequencies of A/a were chosen. We used the odds ratio with 95% confidence interval to assess the strength of this association. Sensitivity analysis and publication bias assessment were performed. Trial sequential analysis (TSA) was performed to evaluate a sufficient sample.

RESULTS

Twenty-two studies assessed the relationship between ApaI polymorphism and the risk of osteoporosis in postmenopausal women. The comprehensive analyses showed no significant association for ApaI polymorphism with postmenopausal osteoporosis in the overall population, equally valid for Asian and Caucasian subgroups with any genetic model. TSA still indicated the results were robust.

CONCLUSION

The present meta-analysis suggests that the VDR ApaI genotype may not affect the risk of postmenopausal osteoporosis in Asians and Caucasians.

Detecting the vitamin D receptor (VDR) protein in mouse and human skeletal muscle: Strain-specific, species-specific and inter-individual variation

Vitamin D, and its receptor (VDR), play roles in muscle development/function, however, VDR detection in muscle has been controversial. Using different sample preparation methods and antibodies, we examined differences in muscle VDR protein abundance between two mouse strains and between mice and humans. The mouse D-6 VDR antibody was not reliable for detecting VDR in mouse muscle, but was suitable for human muscle, while the rabbit D2K6W antibody was valid for mouse and human muscle. VDR protein was generally lower in muscles from C57 B l/6 than FVB/N mice and was higher in human than mouse muscle. Two putative VDR bands were detected in human muscle, possibly representing VDR isoforms/splice variants, with marked inter-individual differences. This study provides new information on detecting VDR in muscle and on inter-mouse strain and inter-human individual differences in VDR expression. These findings may have implications for future pre-clinical and clinical studies and prompt further investigation to confirm possible VDR isoforms in human muscle.

Modulation of the vitamin D/vitamin D receptor system in osteoporosis pathogenesis: insights and therapeutic approaches

Osteoporosis is a prevalent bone disorder characterized by low bone mineral density (BMD) and deteriorated bone microarchitecture, leading to an increased risk of fractures. Vitamin D (VD), an essential nutrient for skeletal health, plays a vital role in maintaining bone homeostasis. The biological effects of VD are primarily mediated through the vitamin D receptor (VDR), a nuclear receptor that regulates the transcription of target genes involved in calcium and phosphate metabolism, bone mineralization, and bone remodeling. In this review article, we conduct a thorough literature search of the PubMed and EMBASE databases, spanning from January 2000 to September 2023. Utilizing the keywords "vitamin D," "vitamin D receptor," "osteoporosis," and "therapy," we aim to provide an exhaustive overview of the role of the VD/VDR system in osteoporosis pathogenesis, highlighting the most recent findings in this field. We explore the molecular mechanisms underlying VDR's effects on bone cells, including osteoblasts and osteoclasts, and discuss the impact of VDR polymorphisms on BMD and fracture risk. Additionally, we examine the interplay between VDR and other factors, such as hormonal regulation, genetic variants, and epigenetic modifications, that contribute to osteoporosis susceptibility. The therapeutic implications of targeting the VDR pathway for osteoporosis management are also discussed. By bringing together these diverse aspects, this review enhances our understanding of the VD/VDR system's critical role in the pathogenesis of osteoporosis and highlights its significance as a potential therapeutic target.

Monotropein inhibits colitis associated cancer through VDR/JAK1/STAT1 regulation of macrophage polarization

Colorectal cancer (CRC) is a growing concern due to its high morbidity and mortality, and the search for effective and less toxic active substances against inflammatory bowel diseases has been a hot topic in the research and development of drugs against CRC. It is reported that monotropein isolated from the roots of Morinda officinalis, can improve Dextran Sodium Sulfate (DSS)-induced ulcerative colitis in mice, but its therapeutic effects and mechanisms for CRC treatment are still to be investigated. In the present study, we first used molecular docking, BLI, CESTA, and DARTS methods to detest whether monotropein targets VDR proteins. In addition, we used tumor cell conditioned co-culture and four models of macrophage polarisation to investigate the regulation of four macrophage polarisations by monotropein using RT-PCR, IF and western blot. Furthermore, we further validated the target of action of monotropein for the treatment of Azoxymethane (AOM)/DSS induced colitis associated cancer (CAC) using knockout animals. Meanwhile, we further explored the mechanism of action of monotropein in regulating polarisation by detecting JAK/STAT1-related genes and proteins. Molecular docking and biofilm interference techniques showed that monotropein bound to the VDR, and additional results from CESTA and DARTS suggested that VDR proteins are targets of monotropein. Furthermore, in tumor cell conditioned co-cultures or LPS + IFN-γ induced RAW264.7 cells, VDR translocation to the nucleus was reduced, JAK1/STAT1 signaling pathway proteins were up-regulated, and macrophages were polarised towards the M1-type after monotropein intervention. Animal models in which normal VDR or myeloid VDR was knocked out confirmed that JAK1 levels in intestinal tissues were increased after monotropein intervention, macrophages were polarised towards the M1 type, and CAC paracarcinomas were ameliorated. Taken together, the present study concluded that monotropein inhibited colitis-associated cancers through macrophage polarisation regulated by VDR/JAK1/STAT1.

Seasonal changes of vitamin D3 and ovarian steroidogenesis in the wild ground squirrels (Citellus dauricus Brandt)

There is mounting evidence that vitamin D3 regulates female reproductive function critically, while little is known about the function of seasonally variable vitamin D3 in regulating ovarian steroidogenesis. This study examined the seasonal expressions of vitamin D receptor (VDR), vitamin D metabolic molecules (CYP2R1, CYP27B1, and CYP24A1), and steroidogenic enzymes (P450scc, 3β-HSD, P450c17, and P450arom) in the ovaries of the wild ground squirrels (Citellus dauricus Brandt) during the different breeding seasons. VDR, CYP2R1, CYP27B1, and CYP24A1 were shown to be localized in different types of ovarian cells in the wild ground squirrels during the breeding and non-breeding seasons. Meanwhile, the mRNA levels of VDR, CYP2R1, CYP27B1, CYP11A1, HSD3B1, CYP17A1, and CYP19A1 in the ovaries were remarkably higher in the breeding season. Furthermore, RNA-seq data of ovaries revealed that 6036 genes were differentially expressed genes (DEGs); further analysis revealed that several DEGs known to be involved in ovarian steroidogenesis pathway and cellular response to vitamin D pathway were identified. In addition, during the breeding season, the concentrations of luteinizing hormone (LH), follicle-stimulating hormone (FSH), progesterone, and 17β-estradiol were greater in the serum of the wild female ground squirrels. This observation was positively correlated with seasonal changes in the concentration of 25(OH)D3, supporting the fact that the 25(OH)D3 content in the ovaries was significantly higher in the breeding season. These findings suggested that seasonal changes in vitamin D3 might regulate the ovarian steroidogenesis of the wild female ground squirrels.

Hepatic vitamin D receptor expression is negatively associated with liver inflammation and fibrosis in patients with chronic HBV infection

The vitamin D receptor (VDR) is a nuclear transcription factor that acts as the main transducer in response to vitamin D (VD), regulating about 3% of the gene expression in the human genome. This study investigated the expression of VDR in the liver of patients with chronic hepatitis B virus (HBV) infection and determined its correlation with liver inflammation and fibrosis. We evaluated the effects of HBV infection on the expression of VDR in vivo and in vitro and further investigate the potential mechanism. Subsequently, the associations between hepatic VDR expression with liver inflammation and fibrosis were statistically analyzed. Results showed that hepatic VDR expression was significantly decreased in patients with chronic HBV infection as compared to healthy individuals. Similarly, in vitro experiments further confirmed that HBV infection could inhibit the expression of VDR in hepatocytes. Mechanistically, HBV was able to directly induce the expression of miR-125a which inhibited the mRNA and protein levels of VDR. Statistical analysis showed that hepatic VDR expression was significantly negatively correlated with liver inflammation and fibrosis in patients. We conclude that inhibition of hepatic vitamin D receptor expression by HBV/miR-125a is negatively associated with liver inflammation and fibrosis in patients with chronic HBV infection.

Discovery of small molecule β-catenin suppressors that enhance immunotherapy

Small molecules directly downregulating β-catenin could potentially offer a more effective therapeutic approach for combating against cancer stem cells, as compared to targeting the downstream components of the Wnt/β-catenin pathway. The challenge, however, lies in the fact that very few β-catenin suppressors have proven clinically effective, leaving a significant gap in medical solutions. Given that E-cadherin has a natural affinity for β-catenin, it stands to reason that agents designed to increase E-cadherin expression might provide an alternative method of regulating β-catenin levels. In this study, we report our discovery of DSS-C12 and DSS-B8, specific ester-based drugs derived from Dan-Shen-Su (DSS) extracted from the herb Salvia miltiorrhiza. Remarkably, these compounds display a potent ability to downregulate β-catenin, while also improving overall survival in post-surgery mice. Additionally, when these drugs are used in combination with PD-L1 checkpoint blockade, they stimulate enhanced systemic immune responses leading to significant suppression of primary tumor growth. In-depth mechanistic studies revealed that DSS-B8 functions as a vitamin D receptor agonist without inducing hypercalcemic effects. Collectively, our findings indicate that DSS-derived small molecules have considerable potential as clinically viable therapeutic strategies for β-catenin deactivation.

Vitamin D3 regulates NSUN2 expression and inhibits melanoma cell proliferation and migration

The activated form of vitamin D3 [1,25-dihydroxyvitamin D3; 1,25(OH)2D3] is important for various physiological processes, such as bone mineralization and calcium metabolism, and plays an anticancer role in numerous cancers as well. Its role in melanoma cells has yet to be proven. NOP2/Sun RNA methyltransferase 2 (NSUN2) is a typical RNA methyltransferase and is highly expressed in a variety of cancer cells. However, the molecular mechanisms underlying the role of 1,25(OH)2D3 and NSUN2 in melanoma cells remain largely unknown. The current study showed that 1,25(OH)2D3 could significantly and specifically inhibit the proliferation and migration of melanoma B16 cells. 1,25(OH)2D3 enhances vitamin D receptor expression while simultaneously reducing NSUN2 expression in melanoma cells. Subsequently, knockdown of NSUN2 suppressed B16 cell proliferation and migration. RNA-Seq results illuminated that DNA replication, cell proliferation and cell cycle pathways were enriched, and genes promoting these pathways were reduced after knocking down Nsun2. Dual-luciferase reporter assays showed that 1,25(OH)2D3 downregulated reporter gene expression was controlled by the Nsun2 promoter. The results suggest that 1,25(OH)2D3 binds to the vitamin D response element located upstream of the Nsun2 promoter to downregulate Nsun2 transcription activity and then affects the gene expression pattern related to cell proliferation and the cell cycle, thereby restraining B16 cell proliferation and migration.

Vitamin D receptor cross-talk with p63 signaling promotes epidermal cell fate

The vitamin D receptor with its ligand 1,25 dihydroxy vitamin D3 (1,25D3) regulates epidermal stem cell fate, such that VDR removal from Krt14 expressing keratinocytes delays re-epithelialization of epidermis after wound injury in mice. In this study we deleted Vdr from Lrig1 expressing stem cells in the isthmus of the hair follicle then used lineage tracing to evaluate the impact on re-epithelialization following injury. We showed that Vdr deletion from these cells prevents their migration to and regeneration of the interfollicular epidermis without impairing their ability to repopulate the sebaceous gland. To pursue the molecular basis for these effects of VDR, we performed genome wide transcriptional analysis of keratinocytes from Vdr cKO and control littermate mice. Ingenuity Pathway analysis (IPA) pointed us to the TP53 family including p63 as a partner with VDR, a transcriptional factor that is essential for proliferation and differentiation of epidermal keratinocytes. Epigenetic studies on epidermal keratinocytes derived from interfollicular epidermis showed that VDR is colocalized with p63 within the specific regulatory region of MED1 containing super-enhancers of epidermal fate driven transcription factor genes such as Fos and Jun. Gene ontology analysis further implicated that Vdr and p63 associated genomic regions regulate genes involving stem cell fate and epidermal differentiation. To demonstrate the functional interaction between VDR and p63, we evaluated the response to 1,25(OH)2D3 of keratinocytes lacking p63 and noted a reduction in epidermal cell fate determining transcription factors such as Fos, Jun. We conclude that VDR is required for the epidermal stem cell fate orientation towards interfollicular epidermis. We propose that this role of VDR involves cross-talk with the epidermal master regulator p63 through super-enhancer mediated epigenetic dynamics.

The vitamin D receptor in osteoblastic cells but not secreted parathyroid hormone is crucial for soft tissue calcification induced by the proresorptive activity of 1,25(OH)2D3

The vitamin D receptor (VDR) is expressed most abundantly in osteoblasts and osteocytes (osteoblastic cells) in bone tissues and regulates bone resorption and calcium (Ca) and phosphate (P) homeostasis in association with parathyroid hormone (PTH). We previously reported that near-physiological doses of vitamin D compounds suppressed bone resorption through VDR in osteoblastic cells. We also found that supra-physiological doses of 1α,25-dihydroxyvitamin D3 [1,25(OH)2D3] induced bone resorption and hypercalcemia via VDR in osteoblastic cells. Here, we report that the latter, a proresorptive dose of 1,25(OH)2D3, causes soft tissue calcification through VDR in osteoblastic cells. High concentrations of vitamin D affect multiple organs and cause soft tissue calcification, with increases in bone resorption and serum Ca levels. Such a variety of symptoms is known as hypervitaminosis D, which is caused by not only high doses of vitamin D but also impaired vitamin D metabolism and diseases that produce 1,25(OH)2D3 ectopically. To clarify the biological process hierarchy in hypervitaminosis D, a proresorptive dose of 1,25(OH)2D3 was administered to wild-type mice in which bone resorption had been suppressed by neutralizing anti-receptor activator of NF-κB ligand (RANKL) antibody. 1,25(OH)2D3 upregulated the serum Ca x P product, concomitantly induced calcification of the aorta, lungs, and kidneys, and downregulated serum PTH levels in control IgG-pretreated wild-type mice. Pretreatment of wild-type mice with anti-RANKL antibody did not affect the down-regulation of PTH levels by 1,25(OH)2D3, but inhibited the increase of the serum Ca x P product and soft tissue calcification induced by 1,25(OH)2D3. Consistent with the effects of anti-RANKL antibody, VDR ablation in osteoblastic cells also did not affect the down-regulation of PTH levels by 1,25(OH)2D3, but suppressed the 1,25(OH)2D3-induced increase of the serum Ca x P product and calcification of soft tissues. Taken together with our previous results, these findings suggest that bone resorption induced by VDR signaling in osteoblastic cells is critical for the pathogenesis of hypervitaminosis D, but PTH is not involved in hypervitaminosis D.

Vitamin D and vitamin D receptor polymorphism in Asian adolescents with primary dysmenorrhea

BACKGROUND

The expression of vitamin D receptor in the normal endometrium and ovaries supports the role of vitamin D in local immunity and inflammatory cytokines regulation.

OBJECTIVE

This study aimed to detect the relation between serum 25(OH)D and primary dysmenorrhea in Asian Adolescents.

METHODS

Two hundred and five (205) adolescents complaining of primary dysmenorrhea (study group) were compared in this prospective study to matched controls (210 controls) after informed consent following the Helsinki Declaration. After thorough evaluation, including a thorough history and pelvic ultrasound examination, blood samples were collected from the studied adolescents to measure serum 25(OH)D and for vitamin D receptor TaqI (rs731236) genotyping. The studied adolescents' data were analyzed using the Pearson's correlation to detect the relation between serum 25(OH)D and primary dysmenorrhea (primary outcome). The secondary outcome measures the odds of primary dysmenorrhea in Asian adolescents with vitamin D receptor TaqI (rs731236) polymorphism.

RESULTS

The serum 25(OH)D was significantly lower in the studied-dysmenorrhea group compared to controls (16.17 ± 7.36 versus 17.65 ± 6.36 ng/ml, respectively), (P = 0.01). The correlation analysis showed a significant negative correlation between the serum 25(OH)D and visual analogue scale of dysmenorrhea (r = -0.9003, P < 0.0001). The studied-dysmenorrhea cases with vitamin D receptor T/t and t/t genotypes had significantly lower serum 25(OH)D (16.7 ± 8.05 and 14.4 ± 4.1 ng/ml, respectively) compared to controls (18.97 ± 6.7 and 21.4 ± 2.45 ng/ml, respectively), (P = 0.02 and 0.004, respectively). The VDR T/t and t/t polymorphisms significantly increase the odds of primary dysmenorrhea (OR 1367.2, P < 0.0001 and OR 106.2, P = 0.001, respectively).

CONCLUSION

The serum 25(OH)D was significantly lower in the studied-dysmenorrhea group compared to controls. The studied-dysmenorrhea cases with VDR T/t and t/t TaqI genotypes had significantly lower serum 25(OH)D compared to controls. The VDR T/t and t/t polymorphisms significantly increase the odds of primary dysmenorrhea.

A multidisciplinary approach disclosing unexplored Aflatoxin B1 roles in severe impairment of vitamin D mechanisms of action

Aflatoxin B1 (AFB1), produced by fungi of the genus Aspergillus, is the most toxic and carcinogenic mycotoxin among the classes of aflatoxins. Previous research showed that AFB1 affects vitamin D receptor (VDR) expression. In the present study, integrated computational and experimental studies were carried out to investigate how AFB1 can interfere with Vitamin D signalling. A competitive antagonism of AFB1 toward RXRα and VDR was hypothesized by comparing the docked complex of AFB1/RXRα and AFB1/VDR ligand-binding domain (LBD) with the X-ray structures of RXRα and VDR bound to known ligands. Accordingly, we demonstrated that AFB1 can affect vitamin D-mediated transcriptional activation of VDR by impairing the formation of protein complexes containing both VDR-RXRα and RXRα/RAR and affecting the subcellular localization of VDR and RXRα. As a whole, our data indicate that AFB1 can interfere with different molecular pathways triggered by vitamin D with an antagonistic mechanism of action.

A review of the critical role of vitamin D axis on the immune system

In recent years, the physiological and molecular functions of vitamin D (Vit-D) have been deeply investigated. At first, Vit-D was considered a regulator of mineral and skeletal homeostasis. However, due to the extensive-expression pattern of Vit-D receptor (VDR) in almost every non-skeletal cell, Vit-D is considered mainly a multifunctional agent with broad effects on various tissues, notably the immune system. The expression of VDR in immune cells such as dendritic cells, monocyte/macrophage, neutrophils, B cells and T cells has been well demonstrated. Besides, such immune cells are capable of metabolizing the active form of Vit-D which means that it can module the immune system in both paracrine and autocrine manners. Vit-D binding protein (DBP), that regulates the levels and homeostasis of Vit-D, is another key molecule capable of modulating the immune system. Recent studies indicate that dysregulation of Vit-D axis, variations in the DBP and VDR genes, and Vit-D levels might be risk factors for the development of autoimmune disease. Here, the current evidence regarding the role of Vit-D axis on the immune system, as well as its role in the development of autoimmune disease will be clarified. Further insight will be given to those studies that investigated the association between single nucleotide polymorphisms of DBP and VDR genes with autoimmune disease susceptibility.

Advances in the Administration of Vitamin D Analogues to Support Bone Health and Treat Chronic Diseases

Vitamin D (VD) exerts a wide variety of biological actions in addition to its well-known roles in calcium homeostasis. Nutritional VD deficiency induces rachitic abnormalities in growing children and osteomalacia in adults, and it has been proposed to underlie the onset and development of multiple non-communicable chronic diseases. Therefore, the administration of VD or synthetic VD analogues represents a promising therapeutic strategy; indeed, VD and a VD agonist have shown clinical promise in mitigating osteoporosis and symptoms of insufficient calcium intake. However, even though high doses of VD analogues have shown pre-clinical efficacy against several diseases, including cancers, they have not yet had wide-spread clinical success. This difference may be due to limitation of clinical doses in light of the inherent calcemic action of VD. An approach to overcome this problem involves the development of VD analogues with lower calcemic activity, which could be administered in high doses to attenuate the onset and progress of disease. In a similar strategy, selective estrogen receptor modulators have had success as anti-osteoporosis drugs, and they have shown benefit for other estrogen target organs by serving as partial antagonists or agonists of estrogen receptor α. It is thus conceivable to generate synthetic partial antagonists or agonists for the VD receptor (VDR) that would exert beneficial effects on bone and other VD target organs. In this review, we discuss the molecular basis of the development of such synthetic VDR ligands from the viewpoint of roles of VDR in gene regulation.

Vitamin D receptor and vitamin D binding protein gene polymorphisms in patients with asthma: a pilot study

BACKGROUND

The effects of vitamin D are exerted by interaction with the vitamin D receptor (VDR) and vitamin D binding protein (VDBP). Polymorphisms in VDR or VDBP genes may affect vitamin D levels, influencing the pathogenesis of asthma and atopy. The aim of this study was to investigate the possible association of VDR and VDBP gene single-nucleotide polymorphisms (SNP), 25-hydroxyvitamin D (25(OH)D), blood eosinophils and total IgE level in subjects with asthma in comparison with healthy individuals.

METHODS

This case-control study enrolled 63 subjects with asthma (45 allergic and 18 non-allergic) and 32 healthy subjects were involved in the study. Sensitization of subjects to inhaled allergens was determined by a skin prick test, lung function was evaluated by spirometry. Blood eosinophil count was determined by standard methods. Serum 25(OH)D and total IgE levels were evaluated by ELISA. Polymorphisms in the VDR and VDBP genes on the 12q13.11 and 4q13.3 chromosomal region were analyzed using TaqMan SNP Genotyping Assay probes.

RESULTS

In asthma patients with vitamin D deficiency (< 20 ng/ml) the allele G of rs11168293 of VDR was more common than in those having insufficiency (20-30 ng/ml) of vitamin D (63% and 31%, p < 0.05). Moreover, asthmatic subject with rs11168293 G allele has significant higher blood eosinophil count compared to asthmatic without the rs11168293 G allele (8.5 ± 12.3% vs. 5.1 ± 1.5%, p < 0.05). Significantly higher IgE level was found in subjects with allergic asthma with the allele A of rs7041 on VDBP gene than in those without this allele (540 ± 110 and 240 ± 80 IU/ml, p < 0.05).

CONCLUSIONS

The association of polymorphisms in VDBP and VDR gene, the rs11168293 G allele and the rs7041 A allele, with 25(OH)D, blood eosinophil and total IgE level in asthma, let us suggest that vitamin D, VDR and VDBP gene polymorphisms are important in pathogenesis of asthma despite its form in relation to atopy.

Design, synthesis and anti-hepatic fibrosis activity of novel diphenyl vitamin D receptor agonists

Hepatic fibrosis poses a significant threat to human health due to excessive extracellular matrix (ECM) deposition leading to liver function damage. Ligand-activated vitamin D receptor (VDR) has been identified as an effective target for hepatic fibrosis, reducing ECM by inhibiting hepatic stellate cell (HSC) activation. Here, a series of novel diphenyl VDR agonists have been rationally designed and synthesized. Among these, compounds 15b, 16i, and 28m showed better transcriptional activity compared to sw-22, which was previously reported to be a potent non-secosteroidal VDR modulator. Moreover, these compounds exhibited outstanding efficacy to inhibit collagen deposition in vitro. In models of CCl₄-induced and bile duct ligation-induced hepatic fibrosis, compound 16i showed the most significant therapeutic effect by ultrasound imaging and histological examination. Moreover, 16i was able to repair liver tissue by reducing the expression levels of fibrosis genes and serum liver function indexes without causing hypercalcemia in mice. In conclusion, compound 16i is a potent VDR agonist with significant anti-hepatic fibrosis action both in vitro and in vivo.

Vitamin D in atherosclerosis and cardiovascular events

Both experimental and clinical findings linking vitamin D to cardiovascular (CV) risk have prompted consideration of its supplementation to improve overall health. Yet several meta-analyses do not provide support for the clinical effectiveness of this strategy. Meanwhile, the understanding of the roles of vitamin D in the pathophysiology of CV diseases has evolved. Specifically, recent work has revealed some non-classical pleiotropic effects of vitamin D, increasing the complexity of vitamin D signalling. Within particular microenvironments (e.g. dysfunctional adipose tissue and atherosclerotic plaque), vitamin D can act locally at cellular level through intracrine/autocrine/paracrine feedforward and feedback circuits. Within atherosclerotic tissues, 'local' vitamin D levels may influence relevant systemic consequences independently of its circulating pool. Moreover, vitamin D links closely to other signalling pathways of CV relevance including those driving cellular senescence, ageing, and age-related diseases-among them CV conditions. This review updates knowledge on vitamin D biology aiming to clarify the widening gap between experimental and clinical evidence. It highlights the potential reverse causation confounding correlation between vitamin D status and CV health, and the need to consider novel pathophysiological concepts in the design of future clinical trials that explore the effects of vitamin D on atherosclerosis and risk of CV events.

Vitamin D Supplementation and Adherence to World Cancer Research Fund (WCRF) Diet Recommendations for Colorectal Cancer Prevention: A Nested Prospective Cohort Study of a Phase II Randomized Trial

Vitamin D and a healthy diet, based on World Cancer Research Fund (WCRF) recommendations, are considered key elements for colorectal cancer (CRC) prevention. In a CRC case-control study, we observed that CRC cases were often significantly Vitamin D deficient while subjects following WCRF recommendations significantly decreased their risk of developing CRC. We conducted a randomized phase-II trial (EudraCT number-2015-000467-14) where 74 CRC patients showed differences in response to Vitamin D supplementation, 2000 IU in average per day, according to gender and microbiota. The aim of this nested study is to correlate Vitamin D (supplementation, serum level and receptor polymorphisms), circulating biomarkers, and events (polyp/adenoma, CRC relapse and other cancers) in concomitant to WCRF recommendation adherence. Vitamin D supplementation did not modulate circulating biomarkers or follow-up events. FokI and TaqI VDR were associated with 25-hydroxyvitamin D (25OHD) levels. Patients following the WCRF recommendations had significantly lower leptin, significantly lower IL-6 (only in females), and significantly lower risk of events (HR = 0.41, 95%CI: 0.18-0.92; p = 0.03; median follow-up 2.6 years). Interestingly, no WCRF adherents had significantly more events if they were in the placebo (p < 0.0001), whereas no influence of WCRF was observed in the Vitamin D arm. While one-year Vitamin D supplementation might be too short to show significant preventive activity, a healthy diet and lifestyle should be the first step for preventive programs.

MiR-874-5p targets VDR/NLRP3 to reduce intestinal pyroptosis and improve intestinal barrier damage in sepsis

BACKGROUND

Vitamin D receptor (VDR) is associated with intestinal barrier damage in sepsis. However, the mechanism of action of miR-874-5p/VDR/NLRP3 axis in disease has not been clearly explained. Therefore, the main content of this study is to explore the mechanism of this axis in intestinal barrier damage in sepsis.

METHODS

In order to confirm the progress of miR-874-5p regulation of VDR/NLRP3 pathway and its involvement in intestinal barrier damage in sepsis, a series of molecular biology and cell biology methods were carried out in this study. These include the establishment of cecal ligation puncture model, Western blot, RT-qPCR, hematoxylin and eosin staining, double luciferase reporting method, Fluorescence in situ hybridization, immunohistochemistry, and enzyme-linked immunosorption assay.

RESULTS

The expression level of miR-874-5p was higher and that of VDR was lower in sepsis. miR-874-5p was negatively correlated with VDR. Inhibition of miR-874-5p expression increased the expression of VDR, decreased the expression of NLRP3, reduced caspase-1 activation and IL-1β secretion, reduced pyroptosis and inflammatory response, and thus protected the intestinal barrier damage in sepsis, all of which were reversed by the downregulation of VDR.

CONCLUSIONS

This study suggested that down-regulation of miR-874-5p or up-regulation of VDR could reduce intestinal barrier damage in sepsis, which may provide potential biomarkers and therapeutic targets for intestinal barrier damage in sepsis.

Association of vitamin D levels and VDR variant (rs2228570) with allergic rhinitis: A meta-analysis and trial sequential analysis

Background

Allergic rhinitis (AR) is a most common allergic condition characterised by cough, sneezing and flu-like symptoms. The aetiology of AR is not known. A deficiency of vitamin D has been associated with various allergic diseases. The role of vitamin D in allergic rhinitis has been explored in different populations, but the results remained inconsistent. Furthermore, vitamin D exerts its effect through the vitamin D receptor (VDR), and genetic variations in the VDR gene significantly alter vitamin D. We performed a meta-analysis to investigate the role of vitamin D levels and VDR polymorphisms with a predisposition to the development of AR.

Materials and methods

All published articles were searched using databases such as PubMed, Google Scholar, and Science Direct. Based on rigorous inclusion and exclusion, appropriate studies were identified. Vitamin D levels, VDR genotype and allele frequencies were extracted from the eligible reports. The meta-analysis was performed by comprehensive meta-analysis software v3.3.

Results

The present meta-analysis comprised 14 reports with 1504 AR patients and 1435 healthy controls. Compared to healthy controls, AR had significantly lower levels of vitamin D (P = 0.000, standard difference of means = -1.287, 95% CI = -1.921 to -0.652). The meta-analysis of two separate investigations, which included 917 cases and 847 controls, showed no predisposition to allergic rhinitis. The trial sequential analysis also demonstrated the need for future case-control studies of VDR polymorphism to examine their involvement in AR.

Conclusions

Lower vitamin D levels are associated with allergic rhinitis, and vitamin D supplementation might be advantageous in addition to standard treatment. The connection of VDR polymorphism (rs2228570) remained equivocal, and additional research is needed.

Summary

Vitamin D exerct its beneficial effect through the vitamin D receptor (VDR) and role of vitamin D and VDR variant in the allergic rhinitis has been contradictories. We performed a meta-analysis to draw a definitive conclusion of importance of vitamin D and VDR polymorphisms in predisposition to development of allergic rhinitis. The observations of the meta-analysis revealed a significant association of lower vitamin D with allergic rhinitis. In addition the VDR rs2228570 variant predisposed subject to develop rhinitis. Collectively, the results of the present investigation redirect requirement of individualized vitamin D supplementation in the management of allergic rhinitis.

Vitamin D and calcium co-therapy mitigates pre-established cadmium nephropathy by regulating renal calcium homeostatic molecules and improving anti-oxidative and anti-inflammatory activities in rat

BACKGROUND

Cadmium (Cd) is a major environmental pollutant and chronic toxicity could induce nephropathy by increasing renal oxidative stress and inflammation. Although vitamin D (VD) and calcium (Ca) prophylactic treatments attenuated Cd-induced cell injury, none of the prior studies measure their renoprotective effects against pre-established Cd-nephropathy.

AIMS

To measure the alleviating effects of VD and/or Ca single and dual therapies against pre-established nephrotoxicity induced by chronic Cd toxicity prior to treatment initiation.

METHODS

Forty male adult rats were allocated into: negative controls (NC), positive controls (PC), Ca, VD and VC groups. The study lasted for eight weeks and all animals, except the NC, received CdCl₂ in drinking water (44 mg/L) throughout the study. Ca (100 mg/kg) and/or VD (350 IU/kg) were given (five times/week) during the last four weeks to the designated groups. Subsequently, the expression of transforming growth factor-β (TGF-β1), inducible nitric oxide synthase (iNOS), neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), VD synthesising (Cyp27b1) and catabolizing (Cyp24a1) enzymes with VD receptor (VDR) and binding protein (VDBP) was measured in renal tissues. Similarly, renal expression of Ca voltage-dependent channels (Ca_V1.1/Ca_V3.1), store-operated channels (RyR1/ITPR1), and binding proteins (CAM/CAMKIIA/S100A1/S100B) were measured. Serum markers of renal function alongside several markers of oxidative stress (MDA/H₂O₂/GSH/GPx/CAT) and inflammation (IL-6/TNF-α/IL-10) together with renal cell apoptosis and expression of caspase-3 were also measured.

RESULTS

The PC group exhibited hypovitaminosis D, hypocalcaemia, hypercalciuria, proteinuria, reduced creatinine clearance, and increased renal apoptosis/necrosis with higher caspase-3 expression. Markers of renal tissue damage (TGF-β1/iNOS/NGAL/KIM-1), oxidative stress (MDA/H₂O₂), and inflammation (TNF-α/IL-1β/IL-6) increased, whilst the antioxidants (GSH/GPx/CAT) and IL-10 decreased, in the PC group. The PC renal tissues also showed abnormal expression of Cyp27b1, Cyp24a1, VDR, and VDBP, alongside Ca-membranous (Ca_V1.1/Ca_V3.1) and store-operated channels (RyR1/ITPR1) and cytosolic Ca-binding proteins (CAM/CAMKIIA/S100A1/S100B). Although VD was superior to Ca monotherapy, their combination revealed the best mitigation effects by attenuating serum and renal tissue Cd concentrations, inflammation and oxidative stress, alongside modulating the expression of VD/Ca-molecules.

CONCLUSIONS

This study is the first to show improved alleviations against Cd-nephropathy by co-supplementing VD and Ca, possibly by better regulation of Ca-dependent anti-oxidative and anti-inflammatory actions.

Vitamin D receptor gene polymorphism and polycystic ovary syndrome susceptibility

BACKGROUND

Polycystic ovary syndrome (PCOS) is the most common endocrinopathy in women. This study was designed to investigate the associations of vitamin D receptor (VDR) gene variants with PCOS risk and the severity of the disease phenotype among Egyptian women.

METHODS

In this study, 185 women with PCOS and 207 fertile women as controls were recruited. Cases were divided into phenotype groups based on their clinical and paraclinical features. Clinical and laboratory data were measured in the patient and control groups. All individuals were genotyped for nine single-nucleotide polymorphisms (SNPs) located across the VDR gene using Taq^Man allelic discrimination real-time polymerase chain reaction.

RESULTS

Women with PCOS were significantly (P ≤ 0.001) higher body mass index (BMI) (22.77 ± 2.5) than controls (21.68 ± 1.85 kg/m²). Women with PCOS had significantly higher anti-Mullerian hormone, prolactin, luteinizing hormone (LH), LH/follicle-stimulating hormone (FSH), free testosterone, total testosterone, and dehydroepiandrosterone sulfate levels than the control group (P ≤ 0.001). The level of FSH was significantly lower in women with PCOS than in the control group (P ≤ 0.001). Analysis of the VDR rs4516035, rs2107301, rs1544410 (BsmI), and rs731236 (TaqI) SNPs showed a significant association with PCOS phenotype A. Furthermore, rs2228570 (FokI), rs3782905, rs7975232 (ApaI), and rs739837 SNPs showed a significant association with PCOS phenotype C. Furthermore, rs11568820 SNP showed a significant association with PCOS phenotype D (P < 0.05).

CONCLUSIONS

The findings of this study indicate that variations in the VDR gene were associated with an increased risk of PCOS in Egyptian women.

Sirt1 protects against intervertebral disc degeneration induced by 1,25-dihydroxyvitamin D insufficiency in mice by inhibiting the NF-κB inflammatory pathway

Background

It has been demonstrated that vitamin D deficiency is associated with an increased risk of patients developing lumbar disc herniation. However, intervertebral disc degeneration caused by active vitamin D deficiency has not been reported. Thus, the purpose of this study was to e investigate the role and mechanism of 1,25-dihydroxyvitamin D (1,25(OH)₂D) insufficiency in promoting intervertebral disc degeneration.

Methods

The phenotypes of intervertebral discs were compared in wild-type mice and mice with heterozygous deletion of 1α-hydroxylase [1α(OH)ase^+/-] at 8 mouths of age using iconography, histology and molecular biology. A mouse model that overexpressed Sirt1 in mesenchymal stem cells on a 1α(OH)ase^+/- background (Sirt1^Tg/1α(OH)ase^+/-) was generated by crossing Prx1-Sirt1 transgenic mice with 1α(OH)ase^+/- mice and comparing their intervertebral disc phenotypes with those of Sirt1^Tg, 1α(OH)ase^+/- and wild-type littermates at 8 months of age. A vitamin D receptor (VDR)-deficient cellular model was generated by knock-down of endogenous VDR using Ad-siVDR transfection into nucleus pulposus cells; VDR-deficient nucleus pulposus cells were then treated with or without resveratrol. The interactions between Sirt1 and acetylated p65, and p65 nuclear localization, were examined using co-immunoprecipitation, Western blots and immunofluorescence staining. VDR-deficient nucleus pulposus cells were also treated with 1,25(OH)₂D₃, or resveratrol or 1,25(OH)₂D₃ plus Ex527 (an inhibitor of Sirt1). Effects on Sirt1 expression, cell proliferation, cell senescence, extracellular matrix protein synthesis and degradation, nuclear factor-κB (NF-κB), and expression of inflammatory molecules, were examined, using immunofluorescence staining, Western blots and real-time RT-PCR.

Results

1,25(OH)₂D insufficiency accelerated intervertebral disc degeneration by reducing extracellular matrix protein synthesis and enhancing extracellular matrix protein degradation with reduced Sirt1 expression in nucleus pulposus tissues. Overexpression of Sirt1 in MSCs protected against 1,25(OH)₂D deficiency-induced intervertebral disc degeneration by decreasing acetylation and phosphorylation of p65 and inhibiting the NF-κB inflammatory pathway. VDR or resveratrol activated Sirt1 to deacetylate p65 and inhibit its nuclear translocation into nucleus pulposus cells. Knockdown of VDR decreased VDR expression and significantly reduced the proliferation and extracellular matrix protein synthesis of nucleus pulposus cells, significantly increased the senescence of nucleus pulposus cells and significantly downregulated Sirt1 expression, and upregulated matrix metallopeptidase 13 (MMP13), tumor necrosis factor-α (TNF-α) and interleukin 1β (IL-1β) expression; the ratios of acetylated and phosphorylated p65/p65 in nucleus pulposus cells were also increased. Treatment of nucleus pulposus cells with VDR reduction using 1,25(OH)₂D₃ or resveratrol partially rescued the degeneration phenotypes, by up-regulating Sirt1 expression and inhibiting NF-κB inflammatory pathway; these effects in nucleus pulposus cells were blocked by inhibition of Sirt1.

Conclusion

Results from this study indicate that the 1,25(OH)₂D/VDR pathway can prevent the degeneration of nucleus pulposus cells by inhibiting the NF-κB inflammatory pathway mediated by Sirt1.The Translational Potential of This Article: This study provides new insights into the use of 1,25(OH)₂D₃ to prevent and treat intervertebral disc degeneration caused by vitamin D deficiency.