Action Of D3 Research Articles

Transcriptomics analysis highlights potential ways in human pathogenesis in Leishmania braziliensis infected with the viral endosymbiont LRV1.

The parasite Leishmania (Viannia) braziliensis is widely distributed in Brazil and is one of the main species associated with human cases of different forms of tegumentary leishmaniasis (TL) such as cutaneous leishmaniasis (CL) and mucosal leishmaniasis (ML). The mechanisms underlying the pathogenesis of TL are still not fully understood, but it is known that factors related to the host and the parasite act in a synergistic and relevant way to direct the response to the infection. In the host, macrophages have a central connection with the parasite and play a fundamental role in the defense of the organism due to their ability to destroy intracellular parasites and present antigens. In the parasite, some intrinsic factors related to the species or even the strain analyzed are fundamental for the outcome of the disease. One of them is the presence of Leishmania RNA Virus 1 (LRV1), an endosymbiont virus that parasitizes some species of Leishmania that triggers a cascade of signals leading to a more severe TL phenotype, such as ML. One of the strategies for understanding factors associated with the immune response generated after Leishmania/host interaction is through the analysis of molecular patterns after infection. Thus, the gene expression profile in human monocyte-derived macrophages obtained from healthy donors infected in vitro with L. braziliensis positive (LbLRV1+) and negative (LbLRV1-) for LRV1 was evaluated. For this, the microarray assay was used and 162 differentially expressed genes were identified in the comparison LbLRV1+ vs. LbLRV1-, 126 upregulated genes for the type I and II interferons (IFN) signaling pathway, oligoadenylate synthase OAS/RNAse L, non-genomic actions of vitamin D3 and RIG-I type receptors, and 36 down-regulated. The top 10 downregulated genes along with the top 10 upregulated genes were considered for analysis. Type I interferon (IFNI)- and OAS-related pathways results were validated by RT-qPCR and Th1/Th2/Th17 cytokines were analyzed by Cytometric Bead Array (CBA) and enzyme-linked immunosorbent assay (ELISA). The microarray results validated by RT-qPCR showed differential expression of genes related to IFNI-mediated pathways with overexpression of different genes in cells infected with LbLRV1+ compared to LbLRV1- and to the control. No significant differences were found in cytokine levels between LbLRV1+ vs. LbLRV1- and control. The data suggest the activation of gene signaling pathways associated with the presence of LRV1 has not yet been reported so far. This study demonstrates, for the first time, the activation of the OAS/RNase L signaling pathway and the non-genomic actions of vitamin D3 when comparing infections with LbLRV1+ versus LbLRV1- and the control. This finding emphasizes the role of LRV1 in directing the host's immune response after infection, underlining the importance of identifying LRV1 in patients with TL to assess disease progression.

Differences in Vitamin D3 Levels in Pulmonary Tuberculosis Patients Before and After One Month of Anti-Tuberculosis Drug Therapy

Pulmonary tuberculosis is an infectious disease caused by infection with the bacteria Mycobacterium tuberculosis. Patients diagnosed with pulmonary tuberculosis will receive Anti-Tuberculosis Drug (OAT) therapy for six months. In the first two months or what is called the intensive phase, the patient will be given a combination of OAT in the form of rifampicin, isoniazid, ethambutol and pyrazinamide. Several types of anti-tuberculosis drugs have the potential to affect vitamin D3 metabolism, either by interfering with absorption, metabolism or changing the action of vitamin D3. The long-term treatment process for pulmonary tuberculosis also results in a decrease in vitamin D3 levels in the blood. This study aims to determine the difference in vitamin D3 levels in pulmonary tuberculosis sufferers before and after one month of anti-tuberculosis drug therapy. This type of research is descriptive observational with a prospective cohort design without comparison. The total sample was 16 newly diagnosed pulmonary tuberculosis sufferers at the Bangetayu, Kedungmundu and Tlogosari Wetan Health Centers, Semarang City. Vitamin D3 levels in serum samples were examined using the ELISA method. The mean vitamin D3 level before OAT therapy was 19.00 ± 10.45 ng/mL, the level decreased after OAT therapy, namely 18.51 ± 4.74 ng/mL. These results indicate that administration of anti-tuberculosis drugs may have an effect on vitamin levels.

Synergistic action of vitamin D3 and A on motor activity regulation in mice model of extrapyramidal syndrome: Correlational insights into astrocyte regulation, cytokine modulation, and dopaminergic activity

BackgroundExtrapyramidal syndromes (EPS) represent neurological side effects of antipsychotic medications, characterized by motor disturbances. While previous studies have indicated the neuroprotective effects of vitamin D and A against EPS, the underlying mechanisms of this protection remain unclear. MethodsTwenty-four adult mice were categorized into four groups: positive and negative control groups, one receiving a dopamine antagonist, and the other receiving both a dopamine antagonist and vitamins D and A. Sections of the corticobasal loop, specifically the motor cortex (M1) and basal nuclei (CPu), were prepared for Immunohistochemistry (IHC) and stained with Glial Fibrillary Acidic Protein (GFAP) to visualize reactive astrocytes. ELISA assays for TNF-α, IL-6, IL-4, IL-13, and dopamine levels were performed on homogenized brain sections. ResultsThe EPS group exhibited a significant increase in TNF-α and IL-6 levels in M1 and CPu. Treatment with dopamine agonists and vitamin D&A resulted in significant reductions in IL-6 levels. Only the Vitamin D&A group showed a significant decline in TNF-α. The EPS group recorded significant decreases in IL-4 and IL-13, with IL-13 significantly elevated in the dopamine agonist and Vitamin D&A groups. IL-4 was notably increased in the Vitamin D&A groups. Dopamine concentration significantly declined in the EPS group, with improvements observed in the groups treated with dopamine agonists, and vitamin D&A. Reactive astrocytes were significantly expressed in the M1 and CPu of the EPS group but poorly expressed in other groups. ConclusionsEPS is linked to astrocyte activation, an upsurge in pro-inflammatory cytokines, a decline in anti-inflammatory cytokines, and dopamine in the corticobasal loop. Administration of vitamin D3 and A was found to suppres pro-inflammatory cytokines and repress anti-inflammatory cytokines associated with astrocyte activation.

Abstract 3867: Identification of novel biomarkers of immune toxicity from CAR T-cell therapy using ultrasensitive NULISA™ proteome technology

Abstract Introduction: The efficacy of anti-CD19 chimeric antigen receptor (CAR) T-cell therapy in patients with relapsed/refractory large B-cell lymphoma (LBCL) is limited by acute toxic events, most notably cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS). Identification of biomarkers of toxicities can allow for selection of high-risk patients and elucidate targetable mechanisms for mitigation. Previous biomarker studies have been constrained by relatively narrow panels of potential mediators and limited time points. Here, we employed NULISA, a novel ultrasensitive assay capable of simultaneously quantifying 204 inflammatory proteins from a single sample, to identify temporal proteome associations with acute toxicities in anti-CD19 CAR T-cell treated patients. Methods: Baseline and post-treatment peripheral blood samples from 80 patients with LBCL who underwent anti-CD19 CAR-T cell therapy were collected within specific time intervals. Plasma samples (n=480) were analyzed with NULISA. CRS and ICANS were graded according to ASTCT consensus criteria. Patients were grouped according to their maximum CRS and ICANS scores. Differential protein abundance across the toxicity groups was assessed using linear mixed effects models fit for each protein, including a time by toxicity group interaction. Proteins showing significant associations were subjected to pathway enrichment and network analysis. Results: Severe CRS and ICANS patient groups showed proteome upregulation beginning on day 1-2 and peaking at day 6-9, followed by extensive downregulation on day 11-16. The strongest upregulated pathway associations of severe CRS and ICANS were inflammatory response, IL-17 signaling, non-genomic action of vitamin D3, regulation of leukocyte proliferation, and cellular extravasation. Downregulated pathways included anti-microbial humoral response and TNFs binding to receptors. In addition to the previously identified inflammatory proteins IL-6, IFNγ, sIL-2Rα, CXCL8, CCL2, our analysis revealed significant association of several novel immune regulators and mediators. These included upregulated Th2 cytokines, IL-17A, IL-22, GZMB, CTLA4, IFNA1;IFNA13, and downregulated S100A12, IL-12B, CCL22, BDNF and TNFSFs, revealing exquisite temporal orchestration of lymphoid and myeloid activities during CRS and ICANS development. Conclusions: This study represents the most comprehensive characterization of immune response to CAR T-cell therapy to date. Using the novel NULISA technology, we identified new proteins and functional pathways associated with CAR T-cell-induced toxicity, implicating them as potential biomarkers. These previously unidentified factors also provide a platform to further investigate the causative immune mechanisms of acute toxicities in CAR-T cell therapy. Citation Format: Riley Kirkpatrick, Joanne Beer, Manishkumar S. Patel, Akansha Jalota, Agrima Mian, Ishara S. Ariyapala, Qinyu Hao, Wei Feng, Xiao-Jun Ma, Yuling Luo, Brian T. Hill, Neetu Gupta. Identification of novel biomarkers of immune toxicity from CAR T-cell therapy using ultrasensitive NULISA™ proteome technology [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3867.

Insight into vitamin D3 action within the ovary-Basic and clinical aspects.

Vitamin D3 is a fat-soluble secosteroid predominantly synthesized in the skin or delivered with a diet. Nevertheless, recently it is considered more as a hormone than a vitamin due to its pleiotropic function within the organism ensured by widely distributed vitamin D receptors and metabolic enzymes. Besides the main role in calcium and phosphorus homeostasis, vitamin D3 was shown to regulate many cellular and metabolic processes in normal and cancerous tissues within the immune system, the cardiovascular system, the respiratory system and the endocrine system. The ovary is an important extraskeletal tissue of vitamin D3 action and local metabolism, indicating its role in the regulation of ovarian functions upon physiological and pathological conditions. This chapter reviews firstly the updated information about vitamin D3 metabolism and triggered intracellular pathways. Furthermore, the basic information about ovarian physiology and several aspects of vitamin D3 effects within the ovary are presented. Finally, the special attention is paid into possible mechanism of vitamin D3 action within ovarian pathologies such as premature ovarian failure, polycystic ovary syndrome, and ovarian cancer, considering its clinical application as alternative therapy.

Vitamin D3 Receptors and Metabolic Enzymes in Hen Reproductive Tissues

In recent years, vitamin D3 has been revealed as an important regulator of reproductive processes in humans and livestock; however, its role in the female reproductive system of poultry is poorly known. The aim of this study was to examine vitamin D3 receptor (VDR and PDIA3) and metabolic enzyme (1α-hydroxylase and 24-hydroxylase) mRNA transcript and protein abundances, and protein localization within the hen ovary, oviductal shell gland, pituitary, liver, and kidney. We demonstrated, for the first time, the patterns of the relative mRNA and protein abundances of examined molecules in the ovary, dependent on follicle development and the layer of follicle wall, as well as in other examined organs. Immunohistochemically, PDIA3, 1α-hydroxylase, and 24-hydroxylase are localized in follicular theca and granulosa layers, luminal epithelium and tubular glands of the shell gland, pituitary, liver, and kidney. These results indicate that reproductive tissues have both receptors, VDR, primarily involved in genomic action, and PDIA3, probably participating in the rapid, non-genomic effect of vitamin D3. The finding of 1α-hydroxylase and 24-hydroxylase expression indicates that the reproductive system of chickens has the potential for vitamin D3 synthesis and inactivation, and may suggest that locally produced vitamin D3 can be considered as a significant factor in the orchestration of ovarian and shell gland function in hens. These results provide a new insight into the potential mechanisms of vitamin D3 action and metabolism in the chicken ovary and oviduct.

Impaired 1,25-dihydroxyvitamin D3 action underlies enthesopathy development in the Hyp mouse model of X-linked hypophosphatemia.

X-linked hypophosphatemia (XLH) is characterized by high serum fibroblast growth factor 23 (FGF23) levels, resulting in impaired 1,25-dihydroxyvitamin D3 (1,25D) production. Adults with XLH develop a painful mineralization of the tendon-bone attachment site (enthesis), called enthesopathy. Treatment of mice with XLH (Hyp) with 1,25D or an anti-FGF23 Ab, both of which increase 1,25D signaling, prevents enthesopathy. Therefore, we undertook studies to determine a role for impaired 1,25D action in enthesopathy development. Entheses from mice lacking vitamin D 1α-hydroxylase (Cyp27b1) (C-/-) had a similar enthesopathy to Hyp mice, whereas deletion of Fgf23 in Hyp mice prevented enthesopathy, and deletion of both Cyp27b1 and Fgf23 in mice resulted in enthesopathy, demonstrating that the impaired 1,25D action due to high FGF23 levels underlies XLH enthesopathy development. Like Hyp mice, enthesopathy in C-/- mice was observed by P14 and was prevented, but not reversed, with 1,25D therapy. Deletion of the vitamin D receptor in scleraxis-expressing cells resulted in enthesopathy, indicating that 1,25D acted directly on enthesis cells to regulate enthesopathy development. These results show that 1,25D signaling was necessary for normal postnatal enthesis maturation and played a role in XLH enthesopathy development. Optimizing 1,25D replacement in pediatric patients with XLH is necessary to prevent enthesopathy.

Pathophysiological aspects of the mechanisms of action of osteotropic drugs in an in vitro experiment on the blood mononuclear cells of patients with frontal bone injuries

Relevance: Pathogenetic treatment of head injuries should be based on the development of post-traumat ic disease, including the role of immune reactions in bone matrix regeneration processes. Repair of bone structures depends on activating stimuli from cells of the immune system. Currently, there is research on the importance of vitamin D in metabolic processes in mesenchymal tissue that affect the formation of the bone matrix and general mineralization of bones, as well as the drug osteogenon, the basis of which are ossein-hydroxyapatite compounds, which stimulate local regulators of bone tissue remodelling and calcium-phosphorus metabolism. Taking into account these data, it will be appropriate to determine the effect of drugs on the processes of bone tissue regeneration in patients with injuries of the frontal bone. Purpose: to determine the effect of various drugs used in the treatment of frontal skull injuries on the pathophysiological mechanisms of inflammation (interleukin-1β, interleukin-10, γ-interferon), stabilization of cell membranes, and the level of regenerative cytokines. Materials and methods: The authors conducted immunological studies on the determination of cytokine factors of inflammation and regeneration in 29 patients with frontal bone injury under the influence of various osteotropic drugs: ossein-hydroxyapatite compounds, osteogenon and vitamin D3 (water-soluble form – aquadetrim), both individually and in combination with each other. The research was carried out in an in vitro experiment in RPMI-1640 medium (Serva, Germany) with blood mononuclear cells from patients. γ-interferon), anti-inflammatory regeneration factor (transforming growth factor-TGF-1β). In the conditions of the experiment, the membrane-protective properties of the above-mentioned osteotropic drugs were investigated on cultures of peritoneal tissue basophils under the conditions of using protamine sulfate as a damaging factor. Results and discussion: it was established that osteogenon and aquadetrim (vit. D3) have a positive effect on the production of cytokines by mononuclear cells in the blood of patients with TLC: they reduce the level of in vitro pro-inflammatory production and increase the production of anti-inflammatory cytokines, especially when used together. Protamine sulphate (liberator) was able to destroy 61% of tissue basophils, SK and osteogenon reduced this percentage, but not reliably. Reliable data were obtained under the action of vitamin, and combinations of ossein-hydroxyapatite compounds + vitamin and osteogenon + vitamin (р=0.01). The use of a general mixture of all drugs did not cancel the effect of liberation of TB. It can be assumed that the main membrane protector is vitamin D3 in the form of a water-soluble form – aquadetrim, which has various directions of pathophysiological influence on the mechanisms of inflammation and regeneration. Conclusions: The growth factor was better stimulated with a mixture of all drugs (~1.7 μg/ml) in combination with vitamin D3. Membrane-protective properties were better expressed under the action of vitamin D3 and combinations of osseinhydroxyapatite compounds + vitamin D3 and osteogenon + vitamin D3. The most effective in activating immunocompetent blood cells were combinations of osteotropic drugs that reduced the level of proinflammatory cytokines and increased the content of anti-inflammatory interleukin-10 in the culture fluid.

Physiological action of vitamin D3 in health and disease

Vitamin D is the common molecules for every steroid that has the biological effects of cholecalciferol. Vitamin D can be synthesized in the mammalian skin after exposed to ultraviolet (UV) waves and this process occur endogenously. Amongst diverse Vitamins, VitD has powerful effects on the immune system. As major components of the diet, vitamins have essential effects on the innate and acquired immune system. The active form of VitD is calcitriol (1,25(OH)2VitD3). Calcitriol (1,25(OH)2VitD3) is the active form of VitD. Calcitriol regulates antimicrobial peptides productions, comprising defensin and cathelicidin, that controller the natural intestine microbiota floor and supports intestinal barriers. VitD in controlling the immune response in infectious and autoimmune diseases. There is a theory that VitD complements could be beneficial for treatment of COVID-19. Vit D has an important anti-inflammatory function on the immune system by reducing the production of pro-inflammatory cytokines and increasing anti-inflammatory cytokines in immune cells. Also, vitamin D deficiency is closely related to chronic diseases such as osteoporosis, type 1 and type 2 diabetes, hypertension, cardiovascular disease and cancer. In addition, recently it was revealed that vitamin D receptors (VDR) are expressed in many organs such as the testes, and vitamin D may be a adjustable regulator of reproductive function and fertility.

Physiological regulation of calcium and phosphorus utilization in laying hens.

Commercial laying hens can produce one egg approximately every 24h. During this process, regulatory systems that control vitamin D3 metabolism, calcium and phosphorus homeostasis, and intestinal uptake of these minerals work in concert to deliver components required for eggshell calcification and bone mineralization. Commercial production cycles have been extended in recent years to last through 100weeks of age, and older hens often exhibit an increased prevalence of skeletal fractures and poor eggshell quality. Issues such as these arise, in part, through imbalances that occur in calcium and phosphorus utilization as hens age. As a result, an in-depth understanding of the mechanisms that drive calcium and phosphorus uptake and utilization is required to develop solutions to these welfare and economic challenges. This paper reviews factors that influence calcium and phosphorus homeostasis in laying hens, including eggshell formation and development and roles of cortical and medullary bone. Metabolism and actions of vitamin D3 and physiological regulation of calcium and phosphorus homeostasis in key tissues are also discussed. Areas that require further research in avian species, such as the role of fibroblast growth factor 23 in these processes and the metabolism and action of bioactive vitamin D3, are highlighted and the importance of using emerging technologies and establishing in vitro systems to perform functional and mechanistic studies is emphasized.

Vitamin D3 actions on astrocyte cells: A target for therapeutic strategy in Parkinson’s disease?

Parkinson's disease (PD) is a neurodegenerative disease characterized by the loss of dopaminergic cells in the substantia nigra pars compacta. PD patients’ brains show neuroinflammation, oxidative stress, and mitochondrial dysfunction. The present study aims to evaluate the neuroprotective activity of VD3 on astrocytes after their exposure to rotenone (ROT) a natural pesticide known to exhibit neurotoxic potential via the inhibition of mitochondrial complex I. Cell viability parameters were evaluated by the MTT test and staining with 7-AAD in cultures of astrocytes treated and untreated with VD3 (0.1, 0.5, and 1.0 ng/mL) and/or ROT (10 µg/mL or 5 µg/mL), and the cytoplasmic production of ROS and the cell death profile were measured by flow cytometry. Glutathione accumulation and ultrastructural changes were evaluated and immunocytochemistry assays for NF-kB and Nrf2 were also carried out. The results showed that VD3 improved the viability of cells previously treated with VD3 and then exposed to ROT, reducing the occurrence of necrotic and apoptotic events. Furthermore, cells exposed to ROT showed increased production of ROS, which decreased significantly with previous treatment with VD3. Importantly, the decrease by ROT in the mitochondrial transmembrane potential was significantly prevented after treating cells with VD3, especially at a concentration of 1 ng/mL. Therefore, treatment with VD3 protected astrocytes from damage caused by ROT, decreasing oxidative stress, decreasing NF-kB and Nrf2 expressions, and improving mitochondrial function. However, further investigation is needed regarding the participation and mechanism of action of VD3 in this cellular model of PD focusing on the crosstalk between Nrf2 and NF-kB.

Previtamin D action spectrum: Challenging CIE towards a standard

In 2006, CIE published a technical report on an action spectrum for the production of previtamin D3 in human skin. CIE procedure is to publish guidelines (e.g., an action spectrum) and let the community test them before moving to define a standard. The CIE previtamin D3 action spectrum has been in use for 15 years, and challenged on several occasions; a number of alternative action spectra have been suggested. To date (2021) no alternative action spectrum has shown clear advantages over the CIE version when tested against experimental outcomes. Thus, the CIE action spectrum remains widely used, but not fully accepted as best representing the photobiology in human skin leading to synthesis of vitamin D. We report on a CIE workshop designed to address the challenges to the CIE action spectrum, and explore alternative action spectra. The workshop concluded that the CIE action spectrum probably requires amendment, with several candidates for consideration in determining any changes. However, until there is a clear alternative, the CIE action spectrum should remain in use whilst ensuring full spectral information about sources of ultraviolet radiation. Thus, results are comparable between studies and can be recalculated to an updated action spectrum if necessary.

An unusual presentation of vitamin D dependent rickets type 2 with low 25 (OH) D3 levels and alopecia: a case report of two siblings

Vitamin D-dependent rickets type 2 (VDDR2) is a rare autosomal recessive (AR) disorder caused either by a mutation in the Vitamin D receptor gene or overexpression of the binding protein leading to end-organ resistance to 1,25 (OH)2 vitamin D3 or defective hormonal actions respectively. It clinically represents growth retardation presenting in the 1st year of life and is frequently associated with alopecia totalis and markedly elevated levels of 1, 25(OH)2 D, which differentiates it from VDDR type 1. We hereby report siblings of a family, who presented with clinical, radiological features of rickets and alopecia totalis. To our knowledge, only a few cases have been reported in literature describing the AR-pattern and low 25(OH)D3 levels in VDDR2.

Therapeutic Potential of a Novel Vitamin D3 Oxime Analogue, VD1-6, with CYP24A1 Enzyme Inhibitory Activity and Negligible Vitamin D Receptor Binding.

The regulation of vitamin D3 actions in humans occurs mainly through the Cytochrome P450 24-hydroxylase (CYP24A1) enzyme activity. CYP24A1 hydroxylates both 25-hydroxycholecalciferol (25(OH)D3) and 1,25-dihydroxycholecalciferol (1,25(OH)2D3), which is the first step of vitamin D catabolism. An abnormal status of the upregulation of CYP24A1 occurs in many diseases, including chronic kidney disease (CKD). CYP24A1 upregulation in CKD and diminished activation of vitamin D3 contribute to secondary hyperparathyroidism (SHPT), progressive bone deterioration, and soft tissue and cardiovascular calcification. Previous studies have indicated that CYP24A1 inhibition may be an effective strategy to increase endogenous vitamin D activity and decrease SHPT. This study has designed and synthesized a novel C-24 O-methyloxime analogue of vitamin D3 (VD1-6) to have specific CYP24A1 inhibitory properties. VD1-6 did not bind to the vitamin D receptor (VDR) in concentrations up to 10−7 M, assessed by a VDR binding assay. The absence of VDR binding by VD1-6 was confirmed in human embryonic kidney HEK293T cultures through the lack of CYP24A1 induction. However, in silico docking experiments demonstrated that VD1-6 was predicted to have superior binding to CYP24A1, when compared to that of 1,25(OH)2D3. The inhibition of CYP24A1 by VD1-6 was also evident by the synergistic potentiation of 1,25(OH)2D3-mediated transcription and reduced 1,25(OH)2D3 catabolism over 24 h. A further indication of CYP24A1 inhibition by VD1-6 was the reduced accumulation of the 24,25(OH)D3, the first metabolite of 25(OH)D catabolism by CYP24A1. Our findings suggest the potent CYP24A1 inhibitory properties of VD1-6 and its potential for testing as an alternative therapeutic candidate for treating SHPT.

Genomic analysis of 1,25-dihydroxyvitamin D3 action in mouse intestine reveals compartment and segment-specific gene regulatory effects

1,25-dihydroxyvitamin D (VD) regulates intestinal calcium absorption in the small intestine (SI) and also reduces risk of colonic inflammation and cancer. However, the intestine compartment-specific target genes of VD signaling are unknown. Here, we examined VD action across three functional compartments of the intestine using RNA-seq to measure VD-induced changes in gene expression and Chromatin Immunoprecipitation with next generation sequencing to measure vitamin D receptor (VDR) genomic binding. We found that VD regulated the expression of 55 shared transcripts in the SI crypt, SI villi, and in the colon, including Cyp24a1, S100g, Trpv6, and Slc30a10. Other VD-regulated transcripts were unique to the SI crypt (162 up, 210 down), villi (199 up, 63 down), or colon (102 up, 28 down), but this did not correlate with mRNA levels of the VDR. Furthermore, bioinformatic analysis identified unique VD-regulated biological functions in each compartment. VDR-binding sites were found in 70% of upregulated genes from the colon and SI villi but were less common in upregulated genes from the SI crypt and among downregulated genes, suggesting some transcript-level VD effects are likely indirect. Consistent with this, we show that VD regulated the expression of other transcription factors and their downstream targets. Finally, we demonstrate that compartment-specific VD-mediated gene expression was associated with compartment-specific VDR-binding sites (<30% of targets) and enrichment of intestinal transcription factor–binding motifs within VDR-binding peaks. Taken together, our data reveal unique spatial patterns of VD action in the intestine and suggest novel mechanisms that could account for compartment-specific functions of this hormone.

Vitamin D May Protect against Breast Cancer through the Regulation of Long Noncoding RNAs by VDR Signaling.

Dietary vitamin D3 has attracted wide interest as a natural compound for breast cancer prevention and therapy, supported by in vitro and animal studies. The exact mechanism of such action of vitamin D3 is unknown and may include several independent or partly dependent pathways. The active metabolite of vitamin D3, 1α,25-dihydroxyvitamin D3 (1,25(OH)2D, calcitriol), binds to the vitamin D receptor (VDR) and induces its translocation to the nucleus, where it transactivates a myriad of genes. Vitamin D3 is involved in the maintenance of a normal epigenetic profile whose disturbance may contribute to breast cancer. In general, the protective effect of vitamin D3 against breast cancer is underlined by inhibition of proliferation and migration, stimulation of differentiation and apoptosis, and inhibition of epithelial/mesenchymal transition in breast cells. Vitamin D3 may also inhibit the transformation of normal mammary progenitors into breast cancer stem cells that initiate and sustain the growth of breast tumors. As long noncoding RNAs (lncRNAs) play an important role in breast cancer pathogenesis, and the specific mechanisms underlying this role are poorly understood, we provided several arguments that vitamin D3/VDR may induce protective effects in breast cancer through modulation of lncRNAs that are important for breast cancer pathogenesis. The main lncRNAs candidates to mediate the protective effect of vitamin D3 in breast cancer are lncBCAS1-4_1, AFAP1 antisense RNA 1 (AFAP1-AS1), metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), long intergenic non-protein-coding RNA 511 (LINC00511), LINC00346, small nucleolar RNA host gene 6 (SNHG6), and SNHG16, but there is a rationale to explore several other lncRNAs.

Vitamin D3 and zinc synergistically induce regulatory T cells and suppress interferon-γ production in mixed lymphocyte culture

Although vitamin D3 (cholecalciferol) and zinc are known to individually shift the immune response towards tolerance, little is known about the effect of their combined administration. This work contributes to understanding the combined action of zinc and vitamin D3 in different in vitro models for immune reactions. Zinc and vitamin D3 in combination boosted the differentiation into Foxp3+CD4+ T cells (Treg). Vitamin D3 alone reduced the percentage of CD4+T-bet+ T cells (TH1). In mixed lymphocyte culture (MLC), therapeutic concentrations of vitamin D3 and zinc in combination suppressed interferon-γ (IFN-γ) secretion more strongly than the single agent treatment. This effect was also detected for a combination of subtherapeutic concentrations of both vitamin D3 and zinc. Vitamin D3, even at nanomolar concentrations, increased intracellular zinc levels. PBMC (peripheral blood mononuclear cells) of individuals at risk of zinc deficiency responded to vitamin D3 treatment with a higher mRNA expression of Zip13. In PBMC, both agents reduced activation-induced IL-17 secretion. In summary, this study shows, for the first time, a vitamin D3-induced upregulation of CD4+Foxp3+ T cells in MLC. The data propose a model where zinc augments the effect of vitamin D3 in certain therapeutic and subtherapeutic concentrations. Lower concentrations of both vitamin D3 and zinc could be used for effective treatment, thus reducing possible side effects from vitamin D3 and zinc. Vitamin D3 and zinc in combination may be a promising and cheap option to treat dysregulated immune response in various conditions.

All-d-Enantiomeric Peptide D3 Designed for Alzheimer's Disease Treatment Dynamically Interacts with Membrane-Bound Amyloid-β Precursors.

Alzheimer's disease (AD) is a severe neurodegenerative pathology with no effective treatment known. Toxic amyloid-β peptide (Aβ) oligomers play a crucial role in AD pathogenesis. All-d-Enantiomeric peptide D3 and its derivatives were developed to disassemble and destroy cytotoxic Aβ aggregates. One of the D3-like compounds is approaching phase II clinical trials; however, high-resolution details of its disease-preventing or pharmacological actions are not completely clear. We demonstrate that peptide D3 stabilizing Aβ monomer dynamically interacts with the extracellular juxtamembrane region of a membrane-bound fragment of an amyloid precursor protein containing the Aβ sequence. MD simulations based on NMR measurement results suggest that D3 targets the amyloidogenic region, not compromising its α-helicity and preventing intermolecular hydrogen bonding, thus creating prerequisites for inhibition of early steps of Aβ conversion into β-conformation and its toxic oligomerization. An enhanced understanding of the D3 action molecular mechanism facilitates development of effective AD treatment and prevention strategies.

A revised action spectrum for vitamin D synthesis by suberythemal UV radiation exposure in humans in vivo

Action spectra are important biological weighting functions for risk/benefit analyses of ultraviolet (UV) radiation (UVR) exposure. One important human benefit of exposure to terrestrial solar UVB radiation (∼295 to 315 nm) is the cutaneous synthesis of vitamin D3 that is initiated by the photoconversion of 7-dehydrocholesterol to previtamin D3 An action spectrum for this process that is followed by other nonphotochemical steps to achieve biologically active vitamin D3 has been established from ex vivo data and is widely used, although its validity has been questioned. We tested this action spectrum in vivo by full- or partial-body suberythemal irradiation of 75 healthy young volunteers with five different polychromatic UVR spectra on five serial occasions. Serum 25-hydroxyvitamin D3 [25(OH)D3] levels, as the most accurate measure of vitamin D3 status, were assessed before, during, and after the exposures. These were then used to generate linear dose-response curves that were different for each UVR spectrum. It was established that the previtamin D3 action spectrum was not valid when related to the serum 25(OH)D3 levels, as weighting the UVR doses with this action spectrum did not result in a common regression line unless it was adjusted by a blue shift, with 5 nm giving the best fit. Such a blue shift is in accord with the published in vitro action spectra for vitamin D3 synthesis. Thus, calculations regarding the risk (typically erythema) versus the benefit of exposure to solar UVR based on the ex vivo previtamin D3 action spectrum require revision.

The Role of Vitamin D3 on the Immune Responses of Monocytes

The active form of vitamin D (Vit D), 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3), is important for cell functions and immunity, as well as its role in bone metabolism. Monocytes/macrophages initiate innate immune response, and is considered to be the cell that first comes into contact with the pathogen. They play effective roles in innate immune and inflammatory responses by intercellular relations and inflammatory mediator secretion. Human THP-1 leukemia cells are frequently used for the in vitro determination of the signal pathways, and the functions of monocyte/macrophages. Nuclear factor-kappa B (NF-κB) are complex networks of signaling pathways that regulate many important cellular behaviors, especially in inflammation, cell death, cell differentiation or proliferation. Midkine (MK) is a cytokine and growth factor that is one of the regulators of inflammatory processes, immune cell functions, proliferation and autoimmunity. The effects of Vit D3 on inflammation and MK secretion in hyperglycemia is still unknown. In this study, it was aimed to determine the dose-dependent effects of Vit D3 on the lipopolysaccharide (LPS) stimulated pro/ anti-inflammatory cytokine, NF-κB and MK responses of THP-1 monocyte cells under normo and hyperglycemic conditions. For this purpose, THP-1 monocyte cells stimulated with LPS (Escherichia coli, 0111, 1 μg/ml) under normoglycemic (glucose 100 mg/dl)/hyperglycemic (glucose 500 mg/dl) conditions, were incubated for 24 hours in the presence and absence of 10-50-100 IU/ml Vit D3. MK, TNF-α, IL-8, IL-10 cytokine levels in the supernatants collected from the wells at the end of the incubation periods, and NF-κB levels in the obtained cell lysates were detected by ELISA method. LPS stimulation induced higher levels of TNF-α, IL-8 and MK responses in hyperglycemic conditions. IL-10 secretions were found to be decreased under hyperglycemia. Vit D3 modulates TNF-α, IL-10 and MK secretions in hyperglycemic conditions. The MK and TNF-α levels were determined to be correlated with NF-κB and IL-10. The results obtained in the study showed that Vit D3 can play a role in immune modulation by regulating NF-κB and cytokine/ chemokine-like molecule MK suppression and proinflammatory/anti-inflammatory cytokine balance. The mechanism of the action of Vit D3 under different conditions should be examined in detail.