RESUMO
Vitamin D is a steroid hormone of great importance in the human body. It is produced in the skin from 7-dehydrocholesterol, upon UV radiation. In order to exert its functions, vitamin D has to be hydroxylated (via CYP27A1 and CYP27B1 hydroxylases), which is followed by its interaction with the vitamin D receptor (VDR) or retinoic acid-related orphan receptors α or γ (RORα and RORγ). By binding with the vitamin D response elements (VDRE) located in the promoter regions, the vitamin D ligand-receptor complex may regulate vitamin D-related genes. Recently, vitamin D has acquired a great interest for its plausible association with cancer development. This review discusses the potential role of vitamin D, its analogues, and enzymes involved in its metabolism with breast cancer incidence and outcome. According to the literature, alterations in the vitamin D endocrine system, both at the mRNA and protein level, have an impact on breast cancer incidence and prognosis. Moreover, specific enzymes participating in vitamin D metabolism may serve as therapeutic targets. Notably, treatment with vitamin D analogues also gives promising results in experimental research. However, given the fact that breast cancer is heterogenous disease, further studies are needed to thoroughly elucidate the potential of vitamin D and enzymes involved in its metabolism in breast cancer development, progression and therapy. Therefore, plausible effects of vitamin D in cancer therapy or prevention have been the principal aim of numerous studies.
Assuntos
Neoplasias da Mama/metabolismo , Vitamina D/metabolismo , Feminino , Humanos , Incidência , Regiões Promotoras Genéticas , Elemento de Resposta à Vitamina D/genéticaRESUMO
Endothelial cell activation through nuclear factor-kappa-B (NFkB) and mitogen-activated protein kinases leads to increased biosynthesis of pro-inflammatory mediators, cellular injury and vascular inflammation under lipopolysaccharide (LPS) exposure. Recent studies report that LPS up-regulated global methyltransferase activity. In this study, we observed that a combination treatment with metformin (MET) and cholecalciferol (VD) blocked the LPS-induced S-adenosylmethionine (SAM)-dependent methyltransferase (SDM) activity in Eahy926 cells. We found that LPS challenge (i) increased arginine methylation through up-regulated protein arginine methyltransferase-1 (PRMT1) mRNA, intracellular concentrations of asymmetric dimethylarginine (ADMA) and homocysteine (HCY); (ii) up-regulated cell senescence through mitigated sirtuin-1 (SIRT1) mRNA, nicotinamide adenine dinucleotide (NAD+) concentration, telomerase activity and total antioxidant capacity; and (iii) lead to endothelial dysfunction through compromised nitric oxide (NOx) production. However, these LPS-mediated cellular events in Eahy926 cells were restored by the synergistic effect of MET and VD. Taken together, this study identified that the dual compound effect inhibits LPS-induced protein arginine methylation, endothelial senescence and dysfunction through the components of epigenetic machinery, SIRT1 and PRMT1, which is a previously unidentified function of the test compounds. In silico results identified the presence of vitamin D response element (VDRE) sequence on PRMT1 suggesting that VDR could regulate PRMT1 gene expression. Further characterization of the cellular events associated with the dual compound challenge, using gene silencing approach or adenoviral constructs for SIRT1 and/or PRMT1 under inflammatory stress, could identify therapeutic strategies to address the endothelial consequences in vascular inflammation-mediated atherosclerosis.
Assuntos
Antioxidantes/farmacologia , Colecalciferol/farmacologia , Metformina/farmacologia , Substâncias Protetoras/farmacologia , Proteína-Arginina N-Metiltransferases/metabolismo , Proteínas Repressoras/metabolismo , Sirtuína 1/metabolismo , Arginina/análogos & derivados , Arginina/metabolismo , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Linhagem Celular , Senescência Celular/efeitos dos fármacos , Endotélio/efeitos dos fármacos , Homocisteína/metabolismo , Humanos , Lipopolissacarídeos/toxicidade , Metilação/efeitos dos fármacos , NAD/metabolismo , Óxido Nítrico/metabolismo , Proteína-Arginina N-Metiltransferases/antagonistas & inibidores , Proteína-Arginina N-Metiltransferases/química , Proteína-Arginina N-Metiltransferases/genética , Proteínas Repressoras/antagonistas & inibidores , Proteínas Repressoras/química , Proteínas Repressoras/genética , S-Adenosilmetionina/metabolismo , Sirtuína 1/genética , Telomerase/metabolismo , Elemento de Resposta à Vitamina DRESUMO
Microglial cell activation is the earliest biomarker of the inflammatory processes that cause central nervous system (CNS) lesions in multiple sclerosis. We hypothesized that 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3) production by activated microglia and macrophages in the CNS inhibits these inflammatory processes. To test this hypothesis, we targeted the Cyp27b1 gene specifically in myeloid cells, then analyzed the influence of disrupted myeloid cell 1,25-(OH)2D3 synthesis on vitamin D3-mediated resistance to experimental autoimmune encephalomyelitis (EAE). Myeloid cell 1,25-(OH)2D3 synthesis was essential for vitamin D3-mediated EAE resistance. Increased CTLA-4 expression in the CNS-infiltrating CD4+ Tconv and Treg cells and decreased splenic B cell CD86 expression correlated with resistance. These new data provide solid support for the view that vitamin D3 reduces MS risk in part through a mechanism involving myeloid cell 1,25-(OH)2D3 production and CTLA-4 upregulation in CNS-infiltrating CD4+ T cells. We suggest that CTLA-4 serves as a vitamin D3-regulated immunological checkpoint in multiple sclerosis prevention.
Assuntos
Linfócitos T CD4-Positivos/imunologia , Antígeno CTLA-4/análise , Calcitriol/biossíntese , Colecalciferol/farmacologia , Encefalomielite Autoimune Experimental/prevenção & controle , Macrófagos/metabolismo , Microglia/metabolismo , 25-Hidroxivitamina D3 1-alfa-Hidroxilase/genética , Animais , Antígeno B7-2/análise , Antígeno CTLA-4/fisiologia , Modelos Animais de Doenças , Feminino , Camundongos , Esclerose Múltipla/prevenção & controle , Elemento de Resposta à Vitamina D/fisiologiaRESUMO
In humans and other primates, 1,25(OH)2vitamin D3 regulates the expression of the cathelicidin antimicrobial peptide (CAMP) gene via toll-like receptor (TLR) signaling that activates the vitamin D pathway. Mice and other mammals lack the vitamin D response element (VDRE) in their CAMP promoters. To elucidate the biological importance of this pathway, we generated transgenic mice that carry a genomic DNA fragment encompassing the entire human CAMP gene and crossed them with Camp knockout (KO) mice. We observed expression of the human transgene in various tissues and innate immune cells. However, in mouse CAMP transgenic macrophages, TLR activation in the presence of 25(OH)D3 did not induce expression of either CAMP or CYP27B1 as would normally occur in human macrophages, reinforcing important species differences in the actions of vitamin D. Transgenic mice did show increased resistance to colonization by Salmonella typhimurium in the gut. Furthermore, the human CAMP gene restored wound healing in the skin of Camp KO mice. Topical application of 1,25(OH)2vitamin D3 to the skin of CAMP transgenic mice induced CAMP expression and increased killing of Staphylococcus aureus in a wound infection model. Our model can help elucidate the biological importance of the vitamin D-cathelicidin pathway in both pathogenic and non-pathogenic states.
Assuntos
Peptídeos Catiônicos Antimicrobianos/genética , Regulação da Expressão Gênica/efeitos dos fármacos , Infecções Estafilocócicas/prevenção & controle , Vitamina D/farmacologia , Animais , Colecalciferol/farmacologia , Feminino , Perfilação da Expressão Gênica , Humanos , Imunidade Inata , Lipopolissacarídeos , Macrófagos/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos DBA , Camundongos Transgênicos , Fagócitos/metabolismo , Fagocitose , Salmonella typhimurium , Transdução de Sinais , Pele/efeitos dos fármacos , Infecções Estafilocócicas/imunologia , Staphylococcus aureus/efeitos dos fármacos , Transgenes , Elemento de Resposta à Vitamina D , CatelicidinasRESUMO
Vitamin D has emerged as a key regulator of innate immune responses to pathogen threat. The hormonal form of vitamin D signals through a nuclear receptor transcription factor and regulates gene transcription. Several papers have shown that vitamin D signaling is active both upstream and downstream of pattern recognition receptors, vanguards of innate immune responses. Crohn's disease (CD) is a relapsing-recurring inflammatory bowel disease (IBD) that arises from dysregulated intestinal innate immunity. Indeed, genetic studies have identified several CD susceptibility markers linked to mechanisms of innate immune responses to infection. Interest in links between vitamin D deficiency and CD has grown substantially, particularly in the last five years. While a number of studies have consistently revealed an association between CD and vitamin D deficiency, recent experimental work has uncovered a compelling mechanistic basis for the contribution of vitamin D deficiency to the pathogenesis of the disease. Moreover, a number of intervention trials have provided generally solid evidence that robust vitamin D supplementation may be of therapeutic benefit to patients with CD. This review summarizes these laboratory and clinical findings.
Assuntos
Doença de Crohn/complicações , Proteína Adaptadora de Sinalização NOD2/imunologia , Receptores de Calcitriol/imunologia , Deficiência de Vitamina D/complicações , Vitamina D/imunologia , Ensaios Clínicos como Assunto , Doença de Crohn/dietoterapia , Doença de Crohn/genética , Doença de Crohn/imunologia , Suplementos Nutricionais , Regulação da Expressão Gênica , Humanos , Imunidade Inata/efeitos dos fármacos , Interleucina-1beta/genética , Interleucina-1beta/imunologia , Proteína Adaptadora de Sinalização NOD2/genética , Receptores de Calcitriol/genética , Transdução de Sinais , Transcrição Gênica , Vitamina D/análogos & derivados , Vitamina D/metabolismo , Vitamina D/uso terapêutico , Deficiência de Vitamina D/dietoterapia , Deficiência de Vitamina D/genética , Deficiência de Vitamina D/imunologia , Elemento de Resposta à Vitamina D/genética , Elemento de Resposta à Vitamina D/imunologiaRESUMO
PD-L1 (programmed death ligand 1) and PD-L2 are cell-surface glycoproteins that interact with programmed death 1 (PD-1) on T cells to attenuate inflammation. PD-1 signaling has attracted intense interest for its role in a pathophysiological context: suppression of anti-tumor immunity. Similarly, vitamin D signaling has been increasingly investigated for its non-classical actions in stimulation of innate immunity and suppression of inflammatory responses. Here, we show that hormonal 1,25-dihydroxyvitamin D (1,25D) is a direct transcriptional inducer of the human genes encoding PD-L1 and PD-L2 through the vitamin D receptor, a ligand-regulated transcription factor. 1,25D stimulated transcription of the gene encoding PD-L1 in epithelial and myeloid cells, whereas the gene encoding the more tissue-restricted PD-L2 was regulated only in myeloid cells. We identified and characterized vitamin D response elements (VDREs) located in both genes and showed that 1,25D treatment induces cell-surface expression of PD-L1 in epithelial and myeloid cells. In co-culture experiments with primary human T cells, epithelial cells pretreated with 1,25D suppressed activation of CD4+ and CD8+ cells and inhibited inflammatory cytokine production in a manner that was abrogated by anti-PD-L1 blocking antibody. Consistent with previous observations of species-specific regulation of immunity by vitamin D, the VDREs are present in primate genes, but neither the VDREs nor the regulation by 1,25D is present in mice. These findings reinforce the physiological role of 1,25D in controlling inflammatory immune responses but may represent a double-edged sword, as they suggest that elevated vitamin D signaling in humans could suppress anti-tumor immunity.
Assuntos
Antígeno B7-H1/agonistas , Regulação da Expressão Gênica/efeitos dos fármacos , Macrófagos/efeitos dos fármacos , Proteína 2 Ligante de Morte Celular Programada 1/agonistas , Regulação para Cima/efeitos dos fármacos , Elemento de Resposta à Vitamina D/efeitos dos fármacos , Vitamina D/análogos & derivados , Animais , Antígeno B7-H1/genética , Antígeno B7-H1/metabolismo , Linhagem Celular , Células Cultivadas , Técnicas de Cocultura , Feminino , Humanos , Macrófagos/citologia , Macrófagos/imunologia , Macrófagos/metabolismo , Masculino , Camundongos , Mucosa Nasal/citologia , Mucosa Nasal/efeitos dos fármacos , Mucosa Nasal/metabolismo , Especificidade de Órgãos , Proteína 2 Ligante de Morte Celular Programada 1/genética , Proteína 2 Ligante de Morte Celular Programada 1/metabolismo , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Especificidade da Espécie , Linfócitos T/citologia , Linfócitos T/efeitos dos fármacos , Linfócitos T/imunologia , Linfócitos T/metabolismo , Vitamina D/farmacologiaRESUMO
The hormonal metabolite of vitamin D, 1,25-dihydroxyvitamin D3 (1,25D), binds to the vitamin D receptor (VDR) and promotes heterodimerization of VDR with a retinoid-X-receptor (RXR) to genomically regulate diverse cellular processes. Herein, it is revealed for the first time that VDR is post-translationally acetylated, and that VDR immunoprecipitated from human embryonic kidney (HEK293) cells displays a dramatic decrease in acetylated receptor in the presence of 1,25D-ligand, sirtuin-1 (SIRT1) deacetylase, or the resveratrol activator of SIRT1. To elucidate the functional significance of VDR deacetylation, vitamin-d-responsive-element (VDRE)-based transcriptional assays were performed to determine if deacetylase overexpression affects VDR/VDRE-driven transcription. In HEK293 kidney and TE85 bone cells, co-transfection of low amounts (1-5ng) of a SIRT1-expression vector elicits a reproducible and statistically significant enhancement (1.3- to 2.6-fold) in transcription mediated by VDREs from the CYP3A4 and cyp24a1 genes, where the magnitude of response to 1,25D-ligand is 6- to 30-fold. Inhibition of SIRT1 via EX-527, or utilization of a SIRT1 loss-of-function mutant (H363Y), resulted in abrogation of SIRT1-mediated VDR potentiation. Studies with a novel, non-acetylatable VDR mutant (K413R) showed that the mutant VDR possesses enhanced responsiveness to 1,25D, in conjunction with reduced, but still significant, sensitivity to exogenous SIRT1, indicating that acetylation of lysine 413 is relevant, but that other acetylated residues in VDR contribute to modulation of its activity. We conclude that the acetylation of VDR comprises a negative feedback loop that attenuates 1,25D-VDR signaling. This regulatory loop is reversed by SIRT1-catalyzed deacetylation of VDR to amplify VDR signaling and 1,25D actions.
Assuntos
Calcitriol/farmacologia , Citocromo P-450 CYP3A/metabolismo , Osteoblastos/efeitos dos fármacos , Receptores de Calcitriol/metabolismo , Receptores X de Retinoides/metabolismo , Sirtuína 1/metabolismo , Acetilação/efeitos dos fármacos , Animais , Calcitriol/metabolismo , Carbazóis/farmacologia , Linhagem Celular Tumoral , Citocromo P-450 CYP3A/genética , Retroalimentação Fisiológica , Regulação da Expressão Gênica , Genes Reporter , Células HEK293 , Humanos , Luciferases/genética , Luciferases/metabolismo , Mutação , Osteoblastos/citologia , Osteoblastos/metabolismo , Ligação Proteica , Ratos , Receptores de Calcitriol/genética , Receptores X de Retinoides/genética , Transdução de Sinais , Sirtuína 1/genética , Transcrição Gênica , Elemento de Resposta à Vitamina DRESUMO
Vitamin D anticancer properties are well known and have been demonstrated in many in vitro and in vivo studies. Mechanistic insights have given an explanation on how vitamin D exerts antineoplastic functions, which are mainly conducted via the canonical vitamin D receptor (VDR)-vitamin D response elements (VDRE) pathway. Numerous findings indicate that dietary components, including vitamin D, could exert chemopreventive effects through alterations of microRNA (miRNA) expression. As miRNAs have important roles in regulating diverse and vital cellular processes, it has been speculated that vitamin D's non-classical effects, including anticancer effects, could be mediated through alterations of miRNA expression level. The current review focuses on up-to-date experimental data on modulation of miRNA expression by vitamin D treatment in cancer, obtained in a cell culture system, animal models and human cohorts. Reported findings in the review show that vitamin D modulates expression of numerous and diverse miRNAs specific for cancer types. Even in its early phases, with many questions remaining to be answered, dissecting the molecular pathways of vitamin D miRNA modulation is an emerging area of science. The complete unraveling of vitamin D molecular mechanisms will emphasize the vitamin D dietary component as a potential chemopreventive agent in cancer and personalized nutrition.
Assuntos
Antineoplásicos/farmacologia , MicroRNAs/biossíntese , Neoplasias/tratamento farmacológico , Receptores de Calcitriol/metabolismo , Elemento de Resposta à Vitamina D/genética , Vitamina D/farmacologia , Animais , Quimioprevenção , Feminino , Humanos , Camundongos , MicroRNAs/genética , Neoplasias/prevenção & controle , Gravidez , Transdução de Sinais/genéticaRESUMO
The factors that regulate expression of genes in the 1C family of human cytosolic sulfotransferases (SULT1C) are not well understood. In a recent study evaluating the effects of a panel of transcription factor activators on SULT1C family member expression in LS180 human colorectal adenocarcinoma cells, we found that SULT1C2 expression was significantly increased by 1α,25-dihydroxyvitamin D3 (VitD3) treatment. The objective of our current study was to identify the mechanism responsible for VitD3-mediated activation of SULT1C2 transcription. VitD3 treatment of LS180 cells activated transcription of a transfected luciferase reporter plasmid that contained â¼5 kilobase pairs (kbp) of the SULT1C2 gene, which included 402 nucleotides (nt) of the noncoding exon 1, all of intron 1, and 21 nt of exon 2. Although computational analysis of the VitD3-responsive region of the SULT1C2 gene identified a pregnane X receptor (PXR)-binding site within exon 1, the transfected 5 kbp SULT1C2 reporter was not activated by treatment with rifampicin, a prototypical PXR agonist. However, deletion or mutation of the predicted PXR-binding site abolished VitD3-mediated SULT1C2 transcriptional activation, identifying the site as a functional vitamin D response element (VDRE). We further demonstrated that vitamin D receptor (VDR) can interact directly with the SULT1C2 VDRE sequence using an enzyme-linked immunosorbent assay-based transcription factor binding assay. In conclusion, VitD3-inducible SULT1C2 transcription is mediated through a VDRE in exon 1. These results suggest a role for SULT1C2 in VitD3-regulated physiologic processes in human intestine.
Assuntos
Adenocarcinoma/enzimologia , Calcitriol/farmacologia , Neoplasias Colorretais/enzimologia , Receptores de Calcitriol/agonistas , Sulfotransferases/metabolismo , Transcrição Gênica/efeitos dos fármacos , Ativação Transcricional/efeitos dos fármacos , Adenocarcinoma/genética , Adenocarcinoma/patologia , Sítios de Ligação , Linhagem Celular Tumoral , Neoplasias Colorretais/genética , Neoplasias Colorretais/patologia , Éxons , Regulação Enzimológica da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Humanos , Receptores de Calcitriol/genética , Receptores de Calcitriol/metabolismo , Sulfotransferases/genética , Transfecção , Elemento de Resposta à Vitamina DRESUMO
Breast cancer is the second most common cancer among women in the US. The active form of vitamin D, 1,25-dihydroxyvitamin D (1,25(OH)2D), is proposed to inhibit cellular processes and to prevent breast cancer. The current studies investigated the effect of 1,25(OH)2D on glutamine metabolism during cancer progression employing Harvey-ras oncogene transformed MCF10A human breast epithelial cells (MCF10A-ras). Treatment with 1,25(OH)2D significantly reduced intracellular glutamine and glutamate levels measured by nuclear magnetic resonance (NMR) by 23±2% each. Further, 1,25(OH)2D treatment reduced glutamine and glutamate flux, determined by [U-(13)C5] glutamine tracer kinetics, into the TCA cycle by 31±0.2% and 17±0.4%, respectively. The relative levels of mRNA and protein abundance of the major glutamine transporter, solute linked carrier family 1 member A5 (SLC1A5), was significantly decreased by 1,25(OH)2D treatment in both MCF10A-ras cells and MCF10A which overexpress ErbB2 (HER-2/neu). Consistent with these results, glutamine uptake was reduced by 1,25(OH)2D treatment and the impact was eliminated with the SLC1A5 inhibitor L-γ-Glutamyl-p-nitroanilide (GPNA). A consensus sequence to the vitamin D responsive element (VDRE) was identified in silico in the SLC1A5 gene promoter, and site-directed mutagenesis analyses with reporter gene studies demonstrate a functional negative VDRE in the promoter of the SLC1A5 gene. siRNA-SLC1A5 transfection in MCF10A-ras cells significantly reduced SLC1A5 mRNA expression as well as decreased viable cell number similar to 1,25(OH)2D treatment. SLC1A5 knockdown also induced an increase in apoptotic cells in MCF10A-ras cells. These results suggest 1,25(OH)2D alters glutamine metabolism in MCF10A-ras cells by inhibiting glutamine uptake and utilization, in part through down-regulation of SLC1A5 transcript abundance. Thus, 1,25(OH)2D down-regulation of the glutamine transporter, SLC1A5, may facilitate vitamin D prevention of breast cancer.
Assuntos
Sistema ASC de Transporte de Aminoácidos/antagonistas & inibidores , Células Epiteliais/efeitos dos fármacos , Glutamina/antagonistas & inibidores , RNA Mensageiro/antagonistas & inibidores , Vitamina D/análogos & derivados , Sistema ASC de Transporte de Aminoácidos/genética , Sistema ASC de Transporte de Aminoácidos/metabolismo , Linhagem Celular Transformada , Ciclo do Ácido Cítrico/efeitos dos fármacos , Ciclo do Ácido Cítrico/genética , Células Epiteliais/metabolismo , Células Epiteliais/patologia , Feminino , Regulação da Expressão Gênica , Ácido Glutâmico/metabolismo , Glutamina/análogos & derivados , Glutamina/metabolismo , Glutamina/farmacologia , Humanos , Cinética , Glândulas Mamárias Humanas/efeitos dos fármacos , Glândulas Mamárias Humanas/metabolismo , Glândulas Mamárias Humanas/patologia , Antígenos de Histocompatibilidade Menor/genética , Antígenos de Histocompatibilidade Menor/metabolismo , Proteína Oncogênica p21(ras)/genética , Proteína Oncogênica p21(ras)/metabolismo , Regiões Promotoras Genéticas , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Receptor ErbB-2/genética , Receptor ErbB-2/metabolismo , Receptores de Calcitriol/genética , Receptores de Calcitriol/metabolismo , Vitamina D/farmacologia , Elemento de Resposta à Vitamina DRESUMO
Antithrombin is a crucial anticoagulant serpin whose even moderate deficiency significantly increases the risk of thrombosis. Most cases with antithrombin deficiency carried genetic defects affecting exons or flanking regions of SERPINC1.We aimed to identify regulatory mutations inSERPINC1 through sequencing the promoter, intron 1 and 2 of this gene in 23 patients with antithrombin deficiency but without known genetic defects. Three cases with moderate antithrombin deficiency (63-78%) carried potential regulatory mutations. One located 200 bp before the initiation ATG and two in intron 1. These mutations disrupted two out of five potential vitamin D receptor elements (VDRE) identified in SERPINC1 with different software. One genetic defect, c.42-1060_-1057dupTTGA, was a new low prevalent polymorphism (MAF: 0.01) with functional consequences on plasma antithrombin levels. The relevance of the vitamin D pathway on the regulation of SERPINC1 was confirmed in a cell model. Incubation of HepG2 with paricalcitol, a vitamin D analog, increased dose-dependently the levels of SERPINC1transcripts and antithrombin released to the conditioned medium. This study shows further evidence of the transcriptional regulation of SERPINC1 by vitamin D and first describes the functional and pathological relevance of mutations affecting VDRE of this gene. Our study opens new perspectives in the search of new genetic defects involved in antithrombin deficiency and the risk of thrombosis as well as in the design of new antithrombotic treatments.
Assuntos
Deficiência de Antitrombina III/genética , Antitrombina III/genética , Predisposição Genética para Doença/genética , Mutação/genética , Elemento de Resposta à Vitamina D/genética , Adulto , Idoso de 80 Anos ou mais , Linhagem Celular Tumoral , Éxons/genética , Feminino , Células Hep G2 , Humanos , Masculino , Pessoa de Meia-Idade , Polimorfismo Genético/genética , Regiões Promotoras Genéticas/genética , Tromboembolia/genética , Trombose/genéticaRESUMO
While many global mechanisms of innate immune responses to pathogen threat are conserved over a vast range of species, the details of those responses and their regulation appear to be highly species-specific. An array of studies over recent years has revealed that hormonal vitamin D is an important regulator of innate immunity. In humans, the hormone-bound VDR directly induces the transcription of genes encoding antimicrobial peptides (AMPs), pattern recognition receptors and key cytokines implicated in innate immune responses. We find that the vitamin D response elements (VDREs) in a number of these human genes are highly conserved in a range of primates, but not present in rodent genes. Consistent with this, VDR target genes encoding AMPs human beta-defensin 2 (HBD2) and cathelicidin (CAMP) and the pattern recognition receptor NOD2 are induced by 1,25(OH)2D in human cells of epithelial or myeloid origin but not similarly regulated in mouse cells. In addition, while conditioned media from human epithelial cells treated with 1,25(OH)2D produced antimicrobial activity against E. coli and the lung pathogen Pseudomonas aeruginosa, no such activity was detected in conditioned media from comparable 1,25(OH)2D-treated mouse epithelial cells. Given that other work has provided evidence that 1,25(OH)2D does control innate immune responses in mouse models of disease, we discuss the species-specific similarities and differences in 1,25(OH)2D-regulated innate immunity.
Assuntos
Catelicidinas/genética , Imunidade Inata/efeitos dos fármacos , Proteína Adaptadora de Sinalização NOD2/genética , Vitamina D3 24-Hidroxilase/genética , Vitamina D/farmacologia , beta-Defensinas/genética , Animais , Peptídeos Catiônicos Antimicrobianos , Sequência de Bases , Catelicidinas/imunologia , Meios de Cultivo Condicionados/farmacologia , Células Dendríticas/citologia , Células Dendríticas/efeitos dos fármacos , Células Dendríticas/imunologia , Células Epiteliais/citologia , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/imunologia , Células Epiteliais/metabolismo , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Regulação da Expressão Gênica , Humanos , Macrófagos/citologia , Macrófagos/efeitos dos fármacos , Macrófagos/imunologia , Camundongos , Monócitos/citologia , Monócitos/efeitos dos fármacos , Monócitos/imunologia , Proteína Adaptadora de Sinalização NOD2/imunologia , Cultura Primária de Células , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/crescimento & desenvolvimento , Transdução de Sinais , Especificidade da Espécie , Elemento de Resposta à Vitamina D , Vitamina D3 24-Hidroxilase/imunologia , beta-Defensinas/imunologiaRESUMO
Uma das principais consequências do envelhecimento populacional é o aumento dos índices de osteoporose, que resulta em risco aumentado de fratura, sobretudo as fraturas relacionadas com traumas de pequena intensidade. Similarmente, a obesidade está sendo diagnosticada em um percentual cada vez maior de indivíduos e, atualmente, acredita-se que mais de meio bilhão da população mundial seja obesa. A vitamina D, dentre as suas funções, desempenha um papel central na homeostase do cálcio e do fósforo e tem sua ação reduzida em indivíduos obesos, possivelmente em consequência do seu sequestro no tecido adiposo. O tecido adiposo é um órgão endócrino capaz de produzir e secretar peptídeos bioativos como leptina, fator de necrose tumoral α (TNF-α) e adiponectina que atuam simultaneamente em algumas vias de regulação do metabolismo energético e ósseo. O objetivo do presente estudo foi avaliar a resposta ao tratamento com suplementação de cálcio e vitamina D sobre marcadores sanguíneos do metabolismo ósseo e energético e do estado inflamatório crônico em 21 pacientes obesos e osteoporóticos com hipovitaminose D, em tratamento com bisfosfonatos durante 12 meses. A idade dos pacientes variou entre 63-86 anos e 20/21 eram mulheres em uso de ácido zoledrônico (47,6%) ou alendronato de sódio (52,4%). Durante o período de acompanhamento não houve alteração do estado nutricional dos pacientes, que permaneceram obesos. Após os 12 meses de tratamento os níveis séricos de vitamina D, osteoprotegerina e adiponectina aumentaram significativamente em relação à medida basal. No mesmo período e nas mesmas condições, os níveis séricos de C-telopeptídeo, fosfatase alcalina óssea, leptina e TNF-α apresentaram redução significativa em relação aos níveis basais pré-tratamento. Apesar da suplementação oral, os níveis de vitamina D mesmo tendo aumentado significativamente em relação aos valores pré-tratamento, permaneceram abaixo da faixa de referência de normalidade. O efeito anti-reabsortivo dos bisfosfonatos foi confirmado e, aparentemente, foi independente do estado de obesidade. A maior disponibilidade de reservatórios de gordura e a alta liposolubilidade da vitamina D, favorecendo o seu sequestro neste sítio, provavelmente resultou na redução da sua biodisponibilidade que poderia explicar a manutenção do estado de hipovitaminose D, a despeito da suplementação durante 12 meses com cálcio e vitamina D. Nossos resultados estão de acordo com os relatos da literatura que favorecem a hipótese de que leptina e adiponectina são sensíveis à ação da vitamina D, caracterizada por uma relação direta entre vitamina D e adiponectina e inversa entre vitamina D e leptina. A ação anti-inflamatória da 25(OH)D, avaliada através da redução dos níveis circulantes de TNF-α também pode ser sugerida a partir dos resultados do presente estudo. Estudos clínicos adicionais serão necessários para tentar elucidar os mecanismos sistêmicos, as interações e níveis circulantes ótimos de vitamina D e adipocinas em obesos e o seu papel na saúde humana
One of the main consequences of population aging is the rising in osteoporosis rates, resulting in increased risk of fracture, particularly fragility fractures. Similarly, obesity is being diagnosed in an increasing percentage of individuals, and currently it is believed that more than half a billion of the world population is obese. Vitamin D, among its many functions, plays a central role in the homeostasis of calcium and phosphorus and has an effect reduced in obese individuals possibly in consequence of sequestration in adipose tissue. The adipose tissue is an endocrine organ able to produce and secrete bioactive peptides such as leptin, tumor necrosis factor α (TNF-α) and adiponectin that simultaneously act in some pathways regulating energy and bone metabolism. The aim of this study was to evaluate the response to treatment with calcium and vitamin D supplementation on blood markers of bone and energy metabolism and a marker of chronic inflammatory state in 21 obese and osteoporotic patients with hypovitaminosis D, treated with bisphosphonates for 12 months. The patients' ages ranged from 63-86 years and 20/21 was women taking zoledronic acid (47.6%) or sodium alendronate (52.4%). During the follow-up period there was no change in the nutritional status of patients who remained obese. After 12 months of treatment serum levels of vitamin D, osteoprotegerin and adiponectin increased significantly compared to baseline values. In the same period and under the same conditions, C-telopeptide, serum bone alkaline phosphatase, leptin and TNF-α showed significant reduction compared to baseline levels. Compared to pre-treatment values, oral supplementation with vitamin D increased significantly the circulating levels that, however, remained below the normal reference range. The anti-resorptive effect of bisphosphonates was confirmed and was apparently independent of the state of obesity. The greater availability of fat reservoirs and the high lipid solubility of vitamin D, favoring its sequestration on this site, probably resulted in reduced bioavailability and thus, persistence of the state of hypovitaminosis D, despite the 12 months supplementation with calcium and vitamin D. Our results are in agreement with most reports from the literature that favor the hypothesis that leptin and adiponectin are sensitive to the action of vitamin D, characterized by a direct relationship between adiponectin and vitamin D and a negative relationship between vitamin D and leptin. The anti-inflammatory action of 25 (OH) D, as measured by the reduction in circulating levels of TNF-α, can also be suggested from the results of this study. Additional clinical studies are needed to try to elucidate the systemic mechanisms, interactions and optimal circulating levels of vitamin D and adipokines in obese and their role in human health
Assuntos
Osteoporose/tratamento farmacológico , Saúde do Idoso , Elemento de Resposta à Vitamina D/efeitos dos fármacosRESUMO
The DEAD box RNA helicase DDX5 is a multifunctional protein involved in the regulatory events of gene expression. Herein, we presented evidence indicating that DDX5 is transcriptionally upregulated by calcitriol, the hormonal form of vitamin D3. In silico analysis revealed the presence of two putative vitamin D response elements (VDREs) in the DDX5 promoter region. Using luciferase reporter assays, we demonstrated that the DDX5 promoter containing these putative VDREs significantly increased the luciferase activity in vitamin D receptor (VDR)-positive SiHa cells upon calcitriol treatment. Electrophoretic mobility shift assays showed the ability of VDR and retinoid X receptor to interact only with the most proximal VDRE, while chromatin immunoprecipitation analysis confirmed the occupancy of this VDRE by the VDR. Finally, we demonstrated that calcitriol significantly increased both DDX5 mRNA and protein in SiHa cells. In summary, this study shows that DDX5 gene is transcriptionally upregulated by calcitriol through a VDRE located in its proximal promoter. Given the importance of DDX5 as a master regulator of differentiation programs, our study suggests that the pro-differentiating properties of calcitriol may be related with the induction of DDX5.
Assuntos
Calcitriol/farmacologia , RNA Helicases DEAD-box/metabolismo , Receptores de Calcitriol/agonistas , Transcrição Gênica/efeitos dos fármacos , Neoplasias do Colo do Útero/enzimologia , Elemento de Resposta à Vitamina D/efeitos dos fármacos , Sequência de Bases , Sítios de Ligação , Linhagem Celular Tumoral , RNA Helicases DEAD-box/genética , Feminino , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Dados de Sequência Molecular , Receptores de Calcitriol/genética , Receptores de Calcitriol/metabolismo , Receptores X de Retinoides/metabolismo , Transfecção , Regulação para Cima , Neoplasias do Colo do Útero/genéticaRESUMO
Sclerostin, the SOST gene product, is a negative regulator of bone formation and a positive regulator of bone resorption. In this study, treatment of human primary osteoblasts, including cells differentiated to an osteocyte-like stage, with 1α,25-dihydroxyvitaminD3 (1,25D) resulted in the dose-dependent increased expression of SOST mRNA. A similar effect was observed in human trabecular bone samples cultured ex vivo, and in osteocyte-like cultures of differentiated SAOS2 cells. Treatment of SAOS2 cells with 1,25D resulted in the production and secretion of sclerostin protein. In silico analysis of the human SOST gene revealed a single putative DR3-type vitamin D response element (VDRE) at position -6216 bp upstream of the transcription start site (TSS). This sequence was confirmed to have strong VDRE activity by luciferase reporter assays and electrophoretic mobility shift analysis (EMSA). Sequence substitution in the VDR/RXR half-sites abolished VDRE reporter activity and binding of nuclear proteins. A 6.3 kb fragment of the human proximal SOST promoter demonstrated responsiveness to 1,25D. The addition of the evolutionary conserved region 5 (ECR5), a known bone specific enhancer region, ahead of the 6.3 kb fragment increased basal promoter activity but did not increase 1,25D responsiveness. Site-specific mutagenesis abolished the responsiveness of the 6.3 kb promoter to 1,25D. We conclude that 1,25D is a direct regulator of human SOST gene and sclerostin protein expression, extending the pathways of control of sclerostin expression. At least some of this responsiveness is mediated by the identified classical VDRE however the nature of the transcriptional regulation by 1,25D warrants further investigation.
Assuntos
Proteínas Morfogenéticas Ósseas/metabolismo , Calcitriol/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Osteócitos/metabolismo , Transcrição Gênica/efeitos dos fármacos , Elemento de Resposta à Vitamina D/fisiologia , Proteínas Adaptadoras de Transdução de Sinal , Proteínas Morfogenéticas Ósseas/genética , Linhagem Celular Tumoral , Regulação da Expressão Gênica/fisiologia , Marcadores Genéticos/genética , Humanos , Osteócitos/citologia , Transcrição Gênica/fisiologiaRESUMO
The two nuclear hormone receptor ligands progesterone and vitamin D (vit.D) play important roles in regulating T cells. The mechanism that connects these two hormones in regulating T cells has not been established. In this study, we report that progesterone is a novel inducer of vit.D receptor (VDR) in T cells and makes T cells highly sensitive to calcitriol. At the molecular level, the induction by progesterone is mediated by two progesterone receptor-binding elements in the intron region after the first noncoding exon of the human VDR gene. Increased expression of VDR by progesterone allows highly sensitive regulation of T cells by vit.D even when vit.D levels are suboptimal. This novel regulatory pathway allows enhanced induction of regulatory T cells but suppression of Th1 and Th17 cells by the two nuclear hormones. The results have significant ramifications in effective regulation of T cells to prevent adverse immune responses during pregnancy.
Assuntos
Calcitriol/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Progesterona/farmacologia , Receptores de Calcitriol/genética , Linfócitos T/efeitos dos fármacos , Linfócitos T/metabolismo , Animais , Sequência de Bases , Feminino , Perfilação da Expressão Gênica , Humanos , Camundongos , Dados de Sequência Molecular , Progesterona/metabolismo , Ligação Proteica , Receptores de Calcitriol/química , Subpopulações de Linfócitos T/citologia , Subpopulações de Linfócitos T/efeitos dos fármacos , Subpopulações de Linfócitos T/imunologia , Subpopulações de Linfócitos T/metabolismo , Linfócitos T/citologia , Linfócitos T/imunologia , Linfócitos T Reguladores/citologia , Linfócitos T Reguladores/efeitos dos fármacos , Linfócitos T Reguladores/imunologia , Linfócitos T Reguladores/metabolismo , Elemento de Resposta à Vitamina DRESUMO
The human ether à go-go 1 potassium channel (hEAG1) is required for cell cycle progression and proliferation of cancer cells. Inhibitors of hEAG1 activity and expression represent potential therapeutic drugs in cancer. Previously, we have shown that hEAG1 expression is downregulated by calcitriol in a variety of cancer cells. Herein, we provided evidence on the regulatory mechanism involved in such repressive effect in cells derived from human cervical cancer. Our results indicate that repression by calcitriol occurs at the transcriptional level and involves a functional negative vitamin D response element (nVDRE) E-box type in the hEAG1 promoter. The described mechanism in this work implies that a protein complex formed by the vitamin D receptor-interacting repressor, the vitamin D receptor, the retinoid X receptor, and the Williams syndrome transcription factor interact with the nVDRE in the hEAG1 promoter in the absence of ligand. Interestingly, all of these transcription factors except the vitamin D receptor-interacting repressor are displaced from hEAG1 promoter in the presence of calcitriol. Our results provide novel mechanistic insights into calcitriol mode of action in repressing hEAG1 gene expression.
Assuntos
Calcitriol/farmacologia , Canais de Potássio Éter-A-Go-Go/genética , Receptores de Calcitriol/genética , Neoplasias do Colo do Útero/genética , Elemento de Resposta à Vitamina D/genética , Linhagem Celular Tumoral , Imunoprecipitação da Cromatina , Regulação para Baixo , Ensaio de Desvio de Mobilidade Eletroforética , Feminino , Humanos , Sequências Reguladoras de Ácido Nucleico , Fatores de Transcrição/metabolismoRESUMO
SCOPE: Vitamin D3, its biologically most active metabolite 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3), and the vitamin D receptor (VDR) are important for adipose tissue biology. METHODS AND RESULTS: We extrapolated genomic VDR association loci in adipocytes from 55 conserved genome-wide VDR-binding sites in nonfat tissues. Taking the genes DUSP10, TRAK1, NRIP1, and THBD as examples, we confirmed the predicted VDR binding sites upstream of their transcription start sites and showed rapid mRNA up-regulation of all four genes in SGBS human pre-adipocytes. Using adipose tissue biopsy samples from 47 participants of a 5-month vitamin D3 intervention study, we demonstrated that all four primary VDR target genes can serve as biomarkers for the vitamin D3 responsiveness of human individuals. Changes in DUSP10 gene expression appear to be the most comprehensive marker, while THBD mRNA changes characterized a rather different group of study participants. CONCLUSION: We present a new approach to predict vitamin D target genes based on conserved genomic VDR-binding sites. Using human adipocytes as examples, we show that such ubiquitous VDR target genes can be used as markers for the individual's response to a supplementation with vitamin D3.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/agonistas , Proteínas Adaptadoras de Transporte Vesicular/agonistas , Tecido Adiposo/metabolismo , Fosfatases de Especificidade Dupla/metabolismo , Fosfatases da Proteína Quinase Ativada por Mitógeno/metabolismo , Proteínas Nucleares/agonistas , Receptores de Calcitriol/agonistas , Trombomodulina/agonistas , Elemento de Resposta à Vitamina D , Proteínas Adaptadoras de Transdução de Sinal/química , Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteínas Adaptadoras de Transporte Vesicular/química , Proteínas Adaptadoras de Transporte Vesicular/genética , Proteínas Adaptadoras de Transporte Vesicular/metabolismo , Tecido Adiposo/patologia , Idoso , Biomarcadores/metabolismo , Calcitriol/metabolismo , Linhagem Celular , Células Cultivadas , Colecalciferol/administração & dosagem , Colecalciferol/deficiência , Colecalciferol/metabolismo , Colecalciferol/uso terapêutico , Sequência Conservada , Suplementos Nutricionais , Fosfatases de Especificidade Dupla/química , Fosfatases de Especificidade Dupla/genética , Finlândia , Humanos , Masculino , Fosfatases da Proteína Quinase Ativada por Mitógeno/química , Fosfatases da Proteína Quinase Ativada por Mitógeno/genética , Proteínas Nucleares/química , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Proteína 1 de Interação com Receptor Nuclear , RNA Mensageiro/metabolismo , Receptores de Calcitriol/genética , Receptores de Calcitriol/metabolismo , Estações do Ano , Trombomodulina/química , Trombomodulina/genética , Trombomodulina/metabolismo , Regulação para Cima , Deficiência de Vitamina D/dietoterapia , Deficiência de Vitamina D/metabolismo , Deficiência de Vitamina D/patologiaRESUMO
Vitamin D is a steroid hormone that regulates mineral homeostasis, bone metabolism and many other physiological processes. The active metabolite of vitamin D, 1α, 25-dihydroxyvitamin D (1,25D(3)), has broad spectrum antitumor activities and potentiates the effects of a number of chemotherapeutic agents. 1,25D(3) exerts its anti-tumor effects mainly through genomic mechanisms involving the regulation of gene transcription through vitamin D response elements (VDREs). More recently, miRNAs have been shown to be regulated by 1,25D(3). miRNAs are short non-coding RNAs that post-transcriptionally modulate the expression of a wide range of genes. Therefore, they have important regulatory roles in the development and progression of many diseases including cancer. This review focuses on the regulation of miRNA expression by 1,25D(3) in cancer model systems and the contribution of the regulated miRNAs to the anti-tumor effect of 1,25D(3). In addition, the impact of miRNAs on 1,25D(3) signaling is discussed.
Assuntos
Regulação Neoplásica da Expressão Gênica , MicroRNAs/genética , Neoplasias/genética , Vitamina D/fisiologia , Neoplasias do Colo/tratamento farmacológico , Neoplasias do Colo/genética , Feminino , Humanos , Leucemia/tratamento farmacológico , Leucemia/genética , Masculino , MicroRNAs/metabolismo , Neoplasias/tratamento farmacológico , Neoplasias Ovarianas/tratamento farmacológico , Neoplasias Ovarianas/genética , Neoplasias da Próstata/tratamento farmacológico , Neoplasias da Próstata/genética , Transdução de Sinais/genética , Vitamina D/farmacologia , Elemento de Resposta à Vitamina DRESUMO
Serotonin and vitamin D have been proposed to play a role in autism; however, no causal mechanism has been established. Here, we present evidence that vitamin D hormone (calcitriol) activates the transcription of the serotonin-synthesizing gene tryptophan hydroxylase 2 (TPH2) in the brain at a vitamin D response element (VDRE) and represses the transcription of TPH1 in tissues outside the blood-brain barrier at a distinct VDRE. The proposed mechanism explains 4 major characteristics associated with autism: the low concentrations of serotonin in the brain and its elevated concentrations in tissues outside the blood-brain barrier; the low concentrations of the vitamin D hormone precursor 25-hydroxyvitamin D [25(OH)D3]; the high male prevalence of autism; and the presence of maternal antibodies against fetal brain tissue. Two peptide hormones, oxytocin and vasopressin, are also associated with autism and genes encoding the oxytocin-neurophysin I preproprotein, the oxytocin receptor, and the arginine vasopressin receptor contain VDREs for activation. Supplementation with vitamin D and tryptophan is a practical and affordable solution to help prevent autism and possibly ameliorate some symptoms of the disorder.