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1.
Artigo em Inglês | MEDLINE | ID: mdl-38763476

RESUMO

The origin of vitamin D2 in herbivorous animals was investigated in vivo in sheep and in bovine as well as mouse gastrointestinal tracts. A high concentration of 25-hydroxyvitamin D2 in blood plasma of sheep both in summer and winter appeared to be incompatible with the undetectable level of vitamin D2 in the pasture on which the sheep were grazing. Studies with bovine rumen contents from a cow grazing the same pasture as the sheep, demonstrated an increased concentration of vitamin D2 on anaerobic incubation in a 'Rusitec' artificial rumen, which was further enhanced when cellulose powder was added as a fermentation substrate. The colon contents of mice that were fed from weaning on a vitamin D-free diet were found to contain vitamin D2. The results of these comparative studies in 3 animal species indicated that vitamin D2 was being generated by microbial anaerobic metabolism in the gastrointestinal tract.


Assuntos
Ergocalciferóis , Rúmen , Animais , Bovinos , Ovinos/microbiologia , Camundongos , Rúmen/microbiologia , Rúmen/metabolismo , Ergocalciferóis/metabolismo , Microbioma Gastrointestinal , Trato Gastrointestinal/metabolismo , Trato Gastrointestinal/microbiologia , Fermentação
2.
Int J Mol Sci ; 25(11)2024 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-38891771

RESUMO

Photoprotective properties of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) to reduce UV-induced DNA damage have been established in several studies. UV-induced DNA damage in skin such as single or double strand breaks is known to initiate several cellular mechanisms including activation of poly(ADP-ribose) (pADPr) polymerase-1 (PARP-1). DNA damage from UV also increases extracellular signal-related kinase (ERK) phosphorylation, which further increases PARP activity. PARP-1 functions by using cellular nicotinamide adenine dinucleotide (NAD+) to synthesise pADPr moieties and attach these to target proteins involved in DNA repair. Excessive PARP-1 activation following cellular stress such as UV irradiation may result in excessive levels of cellular pADPr. This can also have deleterious effects on cellular energy levels due to depletion of NAD+ to suboptimal levels. Since our previous work indicated that 1,25(OH)2D3 reduced UV-induced DNA damage in part through increased repair via increased energy availability, the current study investigated the effect of 1,25(OH)2D3 on UV-induced PARP-1 activity using a novel whole-cell enzyme- linked immunosorbent assay (ELISA) which quantified levels of the enzymatic product of PARP-1, pADPr. This whole cell assay used around 5000 cells per replicate measurement, which represents a 200-400-fold decrease in cell requirement compared to current commercial assays that measure in vitro pADPr levels. Using our assay, we observed that UV exposure significantly increased pADPr levels in human keratinocytes, while 1,25(OH)2D3 significantly reduced levels of UV-induced pADPr in primary human keratinocytes to a similar extent as a known PARP-1 inhibitor, 3-aminobenzamide (3AB). Further, both 1,25(OH)2D3 and 3AB as well as a peptide inhibitor of ERK-phosphorylation significantly reduced DNA damage in UV-exposed keratinocytes. The current findings support the proposal that reduction in pADPr levels may be critical for the function of 1,25(OH)2D3 in skin to reduce UV-induced DNA damage.


Assuntos
Dano ao DNA , Poli(ADP-Ribose) Polimerase-1 , Raios Ultravioleta , Vitamina D , Humanos , Raios Ultravioleta/efeitos adversos , Poli(ADP-Ribose) Polimerase-1/metabolismo , Vitamina D/farmacologia , Vitamina D/metabolismo , Vitamina D/análogos & derivados , Dano ao DNA/efeitos dos fármacos , Queratinócitos/metabolismo , Queratinócitos/efeitos da radiação , Queratinócitos/efeitos dos fármacos , Calcitriol/farmacologia , Calcitriol/metabolismo , Reparo do DNA/efeitos dos fármacos , Fosforilação/efeitos dos fármacos
3.
J Gen Virol ; 104(9)2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37702591

RESUMO

Following infection, the human cytomegalovirus (HCMV) genome becomes rapidly associated with host histones which can contribute to the regulation of viral gene expression. This can be seen clearly during HCMV latency where silencing of the major immediate early promoter (MIEP), normally responsible for expression of the key lytic proteins IE72 and IE86, is mediated by histone methylation and recruitment of heterochromatin protein 1. Crucially, reversal of these histone modifications coupled with histone acetylation drives viral reactivation which can be blocked with specific histone acetyltransferase inhibitors (HATi). In lytic infection, a role for HATi is less clear despite the well-established enhancement of viral replication observed with histone deacetylase inhibitors. Here we report that a number of different broad-acting HATi have a minor impact on viral infection and replication during lytic infection with the more overt phenotypes observed at lower multiplicities of infection. However, specific analyses of the regulation of major immediate early (MIE) gene expression reveal that the HATi C646, which targets p300/CBP, transiently repressed MIE gene expression via inhibition of the MIEP but by 24 h post-infection MIE gene expression was rescued due to compensatory activation of an alternative IE promoter, ip2. This suggested that silencing of the MIEP promoted alternative ip2 promoter activity in lytic infection and, consistent with this, ip2 transcription is impaired in cells infected with a recombinant HCMV that does not auto-repress the MIEP at late times of infection. Furthermore, inhibition of the histone methyltransferases known to be responsible for auto-repression is similarly inhibitory to ip2 transcription in wild-type infected cells. We also observe that these discrete transcriptional activities of the MIEP and ip2 promoter are also reflected in reactivation; essentially in cells where the MIEP is silenced, ip2 activity is easier to detect at very early times post-reactivation whereas in cells where robust activation of the MIEP is observed ip2 transcription is reduced or delayed. Finally, we observe that inhibition of pathways demonstrated to be important for reactivation of HCMV in dendritic cells, e.g. in response to IL-6, are preferentially important for activation of the MIEP and not the ip2 promoter. Together, these data add to the hypothesis that the existence of multiple promoters within the MIE region of HCMV can drive reactivation in a cell type- and ligand-specific manner and also suggest that inter-dependent regulatory activity between the two promoters exists.


Assuntos
Citomegalovirus , Histonas , Humanos , Histonas/genética , Citomegalovirus/genética , Genes Precoces , Fenótipo , Regiões Promotoras Genéticas
4.
Pharmacol Rev ; 72(3): 558-604, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32467152

RESUMO

The calcium-sensing receptor (CaSR) is a class C G protein-coupled receptor that responds to multiple endogenous agonists and allosteric modulators, including divalent and trivalent cations, L-amino acids, γ-glutamyl peptides, polyamines, polycationic peptides, and protons. The CaSR plays a critical role in extracellular calcium (Ca2+ o) homeostasis, as demonstrated by the many naturally occurring mutations in the CaSR or its signaling partners that cause Ca2+ o homeostasis disorders. However, CaSR tissue expression in mammals is broad and includes tissues unrelated to Ca2+ o homeostasis, in which it, for example, regulates the secretion of digestive hormones, airway constriction, cardiovascular effects, cellular differentiation, and proliferation. Thus, although the CaSR is targeted clinically by the positive allosteric modulators (PAMs) cinacalcet, evocalcet, and etelcalcetide in hyperparathyroidism, it is also a putative therapeutic target in diabetes, asthma, cardiovascular disease, and cancer. The CaSR is somewhat unique in possessing multiple ligand binding sites, including at least five putative sites for the "orthosteric" agonist Ca2+ o, an allosteric site for endogenous L-amino acids, two further allosteric sites for small molecules and the peptide PAM, etelcalcetide, and additional sites for other cations and anions. The CaSR is promiscuous in its G protein-coupling preferences, and signals via Gq/11, Gi/o, potentially G12/13, and even Gs in some cell types. Not surprisingly, the CaSR is subject to biased agonism, in which distinct ligands preferentially stimulate a subset of the CaSR's possible signaling responses, to the exclusion of others. The CaSR thus serves as a model receptor to study natural bias and allostery. SIGNIFICANCE STATEMENT: The calcium-sensing receptor (CaSR) is a complex G protein-coupled receptor that possesses multiple orthosteric and allosteric binding sites, is subject to biased signaling via several different G proteins, and has numerous (patho)physiological roles. Understanding the complexities of CaSR structure, function, and biology will aid future drug discovery efforts seeking to target this receptor for a diversity of diseases. This review summarizes what is known to date regarding key structural, pharmacological, and physiological features of the CaSR.


Assuntos
Receptores de Detecção de Cálcio/agonistas , Receptores de Detecção de Cálcio/antagonistas & inibidores , Animais , Sítios de Ligação , Proteínas de Ligação ao GTP/metabolismo , Humanos , Modelos Moleculares , Receptores de Detecção de Cálcio/química , Receptores de Detecção de Cálcio/metabolismo , Transdução de Sinais , Bibliotecas de Moléculas Pequenas/farmacologia
5.
Int J Mol Sci ; 24(5)2023 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-36902353

RESUMO

The calcium-sensing receptor (CaSR) is an important regulator of epidermal function. We previously reported that knockdown of the CaSR or treatment with its negative allosteric modulator, NPS-2143, significantly reduced UV-induced DNA damage, a key factor in skin cancer development. We subsequently wanted to test whether topical NPS-2143 could also reduce UV-DNA damage, immune suppression, or skin tumour development in mice. In this study, topical application of NPS-2143 (228 or 2280 pmol/cm2) to Skh:hr1 female mice reduced UV-induced cyclobutane pyrimidine dimers (CPD) (p < 0.05) and oxidative DNA damage (8-OHdG) (p < 0.05) to a similar extent as the known photoprotective agent 1,25(OH)2 vitamin D3 (calcitriol, 1,25D). Topical NPS-2143 failed to rescue UV-induced immunosuppression in a contact hypersensitivity study. In a chronic UV photocarcinogenesis protocol, topical NPS-2143 reduced squamous cell carcinomas for only up to 24 weeks (p < 0.02) but had no other effect on skin tumour development. In human keratinocytes, 1,25D, which protected mice from UV-induced skin tumours, significantly reduced UV-upregulated p-CREB expression (p < 0.01), a potential early anti-tumour marker, while NPS-2143 had no effect. This result, together with the failure to reduce UV-induced immunosuppression, may explain why the reduction in UV-DNA damage in mice with NPS-2143 was not sufficient to inhibit skin tumour formation.


Assuntos
Receptores de Detecção de Cálcio , Neoplasias Cutâneas , Feminino , Animais , Camundongos , Humanos , Camundongos Pelados , Receptores de Detecção de Cálcio/metabolismo , Raios Ultravioleta , Dano ao DNA , Neoplasias Cutâneas/metabolismo , Dímeros de Pirimidina/metabolismo , Pele/metabolismo
6.
Int J Mol Sci ; 22(12)2021 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-34204449

RESUMO

We recently found that, in human osteoblasts, Homer1 complexes to Calcium-sensing receptor (CaSR) and mediates AKT initiation via mechanistic target of rapamycin complex (mTOR) complex 2 (mTORC2) leading to beneficial effects in osteoblasts including ß-catenin stabilization and mTOR complex 1 (mTORC1) activation. Herein we further investigated the relationship between Homer1 and CaSR and demonstrate a link between the protein levels of CaSR and Homer1 in human osteoblasts in primary culture. Thus, when siRNA was used to suppress the CaSR, we observed upregulated Homer1 levels, and when siRNA was used to suppress Homer1 we observed downregulated CaSR protein levels using immunofluorescence staining of cultured osteoblasts as well as Western blot analyses of cell protein extracts. This finding was confirmed in vivo as the bone cells from osteoblast specific CaSR-/- mice showed increased Homer1 expression compared to wild-type (wt). CaSR and Homer1 protein were both expressed in osteocytes embedded in the long bones of wt mice, and immunofluorescent studies of these cells revealed that Homer1 protein sub-cellular localization was markedly altered in the osteocytes of CaSR-/- mice compared to wt. The study identifies additional roles for Homer1 in the control of the protein level and subcellular localization of CaSR in cells of the osteoblast lineage, in addition to its established role of mTORC2 activation downstream of the receptor.


Assuntos
Proteínas de Arcabouço Homer/metabolismo , Alvo Mecanístico do Complexo 2 de Rapamicina/metabolismo , Osteoblastos/metabolismo , Receptores de Detecção de Cálcio/metabolismo , Animais , Cálcio/metabolismo , Linhagem da Célula , Sobrevivência Celular , Células Cultivadas , Feminino , Expressão Gênica , Glicogênio Sintase Quinase 3 beta/metabolismo , Humanos , Masculino , Camundongos , Camundongos Knockout , Fosforilação , Ligação Proteica , Transporte Proteico , Proteínas Proto-Oncogênicas c-akt/metabolismo , Receptores de Detecção de Cálcio/genética
7.
Int J Mol Sci ; 22(4)2021 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-33669452

RESUMO

Susceptibility to photoimmune suppression and photocarcinogenesis is greater in male than in female humans and mice and is exacerbated in female estrogen receptor-beta knockout (ER-ß-/-) mice. We previously reported that the active vitamin D hormone, 1,25-dihydroxyvitamin D3 (1,25(OH)2D), applied topically protects against the ultraviolet radiation (UV) induction of cutaneous cyclobutane pyrimidine dimers (CPDs) and the suppression of contact hypersensitivity (CHS) in female mice. Here, we compare these responses in female versus male Skh:hr1 mice, in ER-ß-/-/-- versus wild-type C57BL/6 mice, and in female ER-blockaded Skh:hr1 mice. The induction of CPDs was significantly greater in male than female Skh:hr1 mice and was more effectively reduced by 1,25(OH)2D in female Skh:hr1 and C57BL/6 mice than in male Skh:hr1 or ER-ß-/- mice, respectively. This correlated with the reduced sunburn inflammation due to 1,25(OH)2D in female but not male Skh:hr1 mice. Furthermore, although 1,25(OH)2D alone dose-dependently suppressed basal CHS responses in male Skh:hr1 and ER-ß-/- mice, UV-induced immunosuppression was universally observed. In female Skh:hr1 and C57BL/6 mice, the immunosuppression was decreased by 1,25(OH)2D dose-dependently, but not in male Skh:hr1, ER-ß-/-, or ER-blockaded mice. These results reveal a sex bias in genetic, inflammatory, and immune photoprotection by 1,25(OH)2D favoring female mice that is dependent on the presence of ER-ß.


Assuntos
Calcitriol/administração & dosagem , Receptor beta de Estrogênio/metabolismo , Transdução de Sinais/efeitos da radiação , Queimadura Solar/tratamento farmacológico , Queimadura Solar/metabolismo , Protetores Solares/administração & dosagem , Raios Ultravioleta , Administração Cutânea , Animais , Dermatite de Contato/tratamento farmacológico , Modelos Animais de Doenças , Receptor beta de Estrogênio/genética , Feminino , Tolerância Imunológica/efeitos dos fármacos , Tolerância Imunológica/efeitos da radiação , Imuno-Histoquímica , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Dímeros de Pirimidina/metabolismo , Dímeros de Pirimidina/efeitos da radiação , Fatores Sexuais , Pele/efeitos dos fármacos , Pele/metabolismo , Pele/patologia , Pele/efeitos da radiação , Neoplasias Cutâneas/prevenção & controle , Queimadura Solar/prevenção & controle
8.
J Biol Chem ; 294(44): 16337-16350, 2019 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-31527082

RESUMO

The calcium-sensing receptor (CaSR) is critical for skeletal development, but its mechanism of action in osteoblasts is not well-characterized. In the central nervous system (CNS), Homer scaffolding proteins form signaling complexes with two CaSR-related members of the G protein-coupled receptor (GPCR) family C, metabotropic glutamate receptor 1 (mGluR1) and mGluR5. Here, we show that CaSR and Homer1 are co-expressed in mineralized mouse bone and also co-localize in primary human osteoblasts. Co-immunoprecipitation experiments confirmed that Homer1 associates with CaSR in primary human osteoblasts. The CaSR-Homer1 protein complex, whose formation was increased in response to extracellular Ca2+, was bound to mechanistic target of rapamycin (mTOR) complex 2 (mTORC2), a protein kinase that phosphorylates and activates AKT Ser/Thr kinase (AKT) at Ser473 siRNA-based gene-silencing assays with primary osteoblasts revealed that both CaSR and Homer1 are required for extracellular Ca2+-stimulated AKT phosphorylation and thereby inhibit apoptosis and promote AKT-dependent ß-catenin stabilization and cellular differentiation. To confirm the role of the CaSR-Homer1 complex in AKT initiation, we show that in HEK-293 cells, co-transfection with both Homer1c and CaSR, but neither with Homer1c nor CaSR alone, establishes sensitivity of AKT-Ser473 phosphorylation to increases in extracellular Ca2+ concentrations. These findings indicate that Homer1 mediates CaSR-dependent AKT activation via mTORC2 and thereby stabilizes ß-catenin in osteoblasts.


Assuntos
Proteínas de Arcabouço Homer/metabolismo , Alvo Mecanístico do Complexo 2 de Rapamicina/metabolismo , Osteoblastos/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Receptores de Detecção de Cálcio/metabolismo , beta Catenina/metabolismo , Animais , Apoptose/fisiologia , Cálcio/metabolismo , Feminino , Células HEK293 , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fosforilação , Receptores de Detecção de Cálcio/genética , Transdução de Sinais , Serina-Treonina Quinases TOR/metabolismo
9.
J Gen Virol ; 101(6): 635-644, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32375946

RESUMO

Human cytomegalovirus latency and reactivation is a major source of morbidity in immune-suppressed patient populations. Lifelong latent infections are established in CD34+progenitor cells in the bone marrow, which are hallmarked by a lack of major lytic gene expression, genome replication and virus production. A number of studies have shown that inhibition of the major immediate early promoter (MIEP) - the promoter that regulates immediate early (IE) gene expression - is important for the establishment of latency and that, by extension, reactivation requires reversal of this repression of the MIEP. The identification of novel promoters (termed ip1 and ip2) downstream of the MIEP that can drive IE gene expression has led to speculation over the precise role of the MIEP in reactivation. In this study we show that IE transcripts arise from both the MIEP and ip2 promoter in the THP1 cell macrophage cell line and also CD14+monocytes stimulated with phorbol ester. In contrast, we show that in in vitro generated dendritic cells or macrophages that support HCMV reactivation IE transcripts arise predominantly from the MIEP and not the intronic promoters. Furthermore, inhibition of histone modifying enzyme activity confirms the view that the MIEP is predominantly regulated by the activity of cellular chromatin. Finally, we observe that ip2-derived IE transcription is cycloheximide-sensitive in reactivating DCs, behaviour consistent with an early gene designation. Taken together, these data argue that MIEP activity is still important for HCMV reactivation but ip2 activity could play cell-type-specific roles in reactivation.


Assuntos
Citomegalovirus/genética , Células Dendríticas/virologia , Genes Precoces/genética , Proteínas Imediatamente Precoces/genética , Regiões Promotoras Genéticas/genética , Células-Tronco/virologia , Transcrição Gênica/genética , Cromatina/genética , Infecções por Citomegalovirus/virologia , Regulação Viral da Expressão Gênica/genética , Humanos , Macrófagos/virologia , Monócitos/virologia , Células THP-1/virologia , Ativação Viral/genética , Latência Viral/genética
10.
Genet Res (Camb) ; 102: e4, 2020 06 10.
Artigo em Inglês | MEDLINE | ID: mdl-32517826

RESUMO

Wild sheep and many primitive domesticated breeds have two coats: coarse hairs covering shorter, finer fibres. Both are shed annually. Exploitation of wool for apparel in the Bronze Age encouraged breeding for denser fleeces and continuously growing white fibres. The Merino is regarded as the culmination of this process. Archaeological discoveries, ancient images and parchment records portray this as an evolutionary progression, spanning millennia. However, examination of the fleeces from feral, two-coated and woolled sheep has revealed a ready facility of the follicle population to change from shedding to continuous growth and to revert from domesticated to primitive states. Modifications to coat structure, colour and composition have occurred in timeframes and to sheep population sizes that exclude the likelihood of variations arising from mutations and natural selection. The features are characteristic of the domestication phenotype: an assemblage of developmental, physiological, skeletal and hormonal modifications common to a wide variety of species under human control. The phenotypic similarities appeared to result from an accumulation of cryptic genetic changes early during vertebrate evolution. Because they did not affect fitness in the wild, the mutations were protected from adverse selection, becoming apparent only after exposure to a domestic environment. The neural crest, a transient embryonic cell population unique to vertebrates, has been implicated in the manifestations of the domesticated phenotype. This hypothesis is discussed with reference to the development of the wool follicle population and the particular roles of Notch pathway genes, culminating in the specific cell interactions that typify follicle initiation.


Assuntos
Evolução Molecular , Mutação , Crista Neural/metabolismo , Receptores Notch/genética , Seleção Genética , Lã/crescimento & desenvolvimento , Animais , Domesticação , Ovinos , Lã/metabolismo , Lã/fisiologia
11.
Adv Exp Med Biol ; 1268: 227-253, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32918222

RESUMO

Exposure of skin cells to UV radiation results in DNA damage, which if inadequately repaired, may cause mutations. UV-induced DNA damage and reactive oxygen and nitrogen species also cause local and systemic suppression of the adaptive immune system. Together, these changes underpin the development of skin tumours. The hormone derived from vitamin D, calcitriol (1,25-dihydroxyvitamin D3) and other related compounds, working via the vitamin D receptor and at least in part through endoplasmic reticulum protein 57 (ERp57), reduce cyclobutane pyrimidine dimers and oxidative DNA damage in keratinocytes and other skin cell types after UV. Calcitriol and related compounds enhance DNA repair in keratinocytes, in part through decreased reactive oxygen species, increased p53 expression and/or activation, increased repair proteins and increased energy availability in the cell when calcitriol is present after UV exposure. There is mitochondrial damage in keratinocytes after UV. In the presence of calcitriol, but not vehicle, glycolysis is increased after UV, along with increased energy-conserving autophagy and changes consistent with enhanced mitophagy. Reduced DNA damage and reduced ROS/RNS should help reduce UV-induced immune suppression. Reduced UV immune suppression is observed after topical treatment with calcitriol and related compounds in hairless mice. These protective effects of calcitriol and related compounds presumably contribute to the observed reduction in skin tumour formation in mice after chronic exposure to UV followed by topical post-irradiation treatment with calcitriol and some, though not all, related compounds.


Assuntos
Calcitriol/farmacologia , Transformação Celular Neoplásica/efeitos dos fármacos , Transformação Celular Neoplásica/efeitos da radiação , Dano ao DNA/efeitos dos fármacos , Raios Ultravioleta/efeitos adversos , Vitamina D/farmacologia , Animais , Calcitriol/química , Calcitriol/metabolismo , Humanos , Vitamina D/química , Vitamina D/metabolismo , Vitaminas/química , Vitaminas/metabolismo , Vitaminas/farmacologia
12.
Adv Exp Med Biol ; 1268: 257-283, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32918223

RESUMO

Nonmelanoma skin cancers including basal and squamous cell carcinomas (SCC and BCC) represent a significant clinical problem due to their relatively high incidence, imposing an economic burden to healthcare systems around the world. It is accepted that ultraviolet radiation (UVR: λ = 290-400 nm) plays a crucial role in the initiation and promotion of BCC and SCC with UVB (λ = 290-320 nm) having a central role in this process. On the other hand, UVB is required for vitamin D3 (D3) production in the skin, which supplies >90% of the body's requirement for this prohormone. Prolonged exposure to UVB can also generate tachysterol and lumisterol. Vitamin D3 itself and its canonical (1,25(OH)2D3) and noncanonical (CYP11A1-intitated) D3 hydroxyderivatives show photoprotective functions in the skin. These include regulation of keratinocyte proliferation and differentiation, induction of anti-oxidative responses, inhibition of DNA damage and induction of DNA repair mechanisms, and anti-inflammatory activities. Studies in animals have demonstrated that D3 hydroxyderivatives can attenuate UVB or chemically induced epidermal cancerogenesis and inhibit growth of SCC and BCC. Genomic and non-genomic mechanisms of action have been suggested. In addition, vitamin D3 itself inhibits hedgehog signaling pathways which have been implicated in many cancers. Silencing of the vitamin D receptor leads to increased propensity to develop UVB or chemically induced epidermal cancers. Other targets for vitamin D compounds include 1,25D3-MARRS, retinoic orphan receptors α and γ, aryl hydrocarbon receptor, and Wnt signaling. Most recently, photoprotective effects of lumisterol hydroxyderivatives have been identified. Clinical trials demonstrated a beneficial role of vitamin D compounds in the treatment of actinic keratosis. In summary, recent advances in vitamin D biology and pharmacology open new exciting opportunities in chemoprevention and treatment of skin cancers.


Assuntos
Neoplasias Cutâneas/etiologia , Neoplasias Cutâneas/prevenção & controle , Vitamina D/química , Animais , Progressão da Doença , Humanos , Receptores de Calcitriol/metabolismo , Pele/efeitos dos fármacos , Pele/metabolismo , Pele/efeitos da radiação , Neoplasias Cutâneas/metabolismo , Neoplasias Cutâneas/patologia , Raios Ultravioleta/efeitos adversos , Vitamina D/metabolismo , Vitamina D/farmacologia , Vitaminas/química , Vitaminas/metabolismo , Vitaminas/farmacologia
13.
Lab Invest ; 97(6): 706-724, 2017 06.
Artigo em Inglês | MEDLINE | ID: mdl-28218743

RESUMO

Ultraviolet B (UVB), in addition to having carcinogenic activity, is required for the production of vitamin D3 (D3) in the skin which supplies >90% of the body's requirement. Vitamin D is activated through hydroxylation by 25-hydroxylases (CYP2R1 or CYP27A1) and 1α-hydroxylase (CYP27B1) to produce 1,25(OH)2D3, or through the action of CYP11A1 to produce mono-di- and trihydroxy-D3 products that can be further modified by CYP27B1, CYP27A1, and CYP24A1. The active forms of D3, in addition to regulating calcium metabolism, exert pleiotropic activities, which include anticarcinogenic and anti-melanoma effects in experimental models, with photoprotection against UVB-induced damage. These diverse effects are mediated through an interaction with the vitamin D receptor (VDR) and/or as most recently demonstrated through action on retinoic acid orphan receptors (ROR)α and RORγ. With respect to melanoma, low levels of 25(OH)D are associated with thicker tumors and reduced patient survival. Furthermore, single-nucleotide polymorphisms of VDR and the vitamin D-binding protein (VDP) genes affect melanomagenesis or disease outcome. Clinicopathological analyses have shown positive correlation between low or undetectable expression of VDR and/or CYP27B1 in melanoma with tumor progression and shorter overall (OS) and disease-free survival (DFS) times. Paradoxically, this correlation was reversed for CYP24A1 (inactivating 24-hydroxylase), indicating that this enzyme, while inactivating 1,25(OH)2D3, can activate other forms of D3 that are products of the non-canonical pathway initiated by CYP11A1. An inverse correlation has been found between the levels of RORα and RORγ expression and melanoma progression and disease outcome. Therefore, we propose that defects in vitamin D signaling including D3 activation/inactivation, and the expression and activity of the corresponding receptors, affect melanoma progression and the outcome of the disease. The existence of multiple bioactive forms of D3 and alternative receptors affecting the behavior of melanoma should be taken into consideration when applying vitamin D management for melanoma therapy.


Assuntos
Melanoma/metabolismo , Receptores de Calcitriol , Vitamina D , Animais , Sistema Enzimático do Citocromo P-450/metabolismo , Progressão da Doença , Epiderme/metabolismo , Epiderme/fisiologia , Humanos , Camundongos , Receptores de Calcitriol/metabolismo , Receptores de Calcitriol/fisiologia , Transdução de Sinais/fisiologia , Raios Ultravioleta , Vitamina D/metabolismo , Vitamina D/fisiologia
14.
Biochemistry ; 55(34): 4737-41, 2016 08 30.
Artigo em Inglês | MEDLINE | ID: mdl-27517125

RESUMO

The Parkinson's disease-associated protein α-synuclein exhibits significant conformational heterogeneity. Bacterially expressed α-synuclein is known to bind to copper, resulting in the formation of aggregation-prone compact conformations. However, in vivo, α-synuclein undergoes acetylation at its N-terminus. Here the effect of this modification and the pathological H50Q mutation on copper binding and subsequent conformational transitions were investigated by electrospray ionization-ion mobility spectrometry-mass spectrometry. We demonstrate that acetylation perturbs the ability of α-synuclein to bind copper and that the H50Q missense mutation in the presence of N-terminal acetylation prevents copper binding. These modifications and mutations prevent the formation of the most compact conformations and inhibit copper-induced aggregation.


Assuntos
Cobre/metabolismo , alfa-Sinucleína/química , alfa-Sinucleína/genética , Acetilação , Humanos , Mutação de Sentido Incorreto , Doença de Parkinson/genética , Doença de Parkinson/metabolismo , Agregados Proteicos/genética , Agregação Patológica de Proteínas/genética , Agregação Patológica de Proteínas/metabolismo , Ligação Proteica , Conformação Proteica , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Espectrometria de Massas por Ionização por Electrospray , alfa-Sinucleína/metabolismo
15.
BMC Musculoskelet Disord ; 17: 336, 2016 08 11.
Artigo em Inglês | MEDLINE | ID: mdl-27515154

RESUMO

BACKGROUND: Improving vitamin D (25-OHD) status may be an important modifiable factor that could reduce disability severity, fall-rates and mortality associated after hip fracture surgery. Providing a loading-dose post-surgery may overcome limitations in adherence to daily supplementation. METHOD: In this randomized, double-blind, placebo-controlled trial, 218 adults, aged 65-years or older, requiring hip fracture surgery were assigned to receive a single loading-dose of cholecalciferol (250,000 IU vitamin-D3, the REVITAHIP - Replenishment of Vitamin D in Hip Fracture strategy) or placebo, both receiving daily vitamin-D(800 IU) and calcium (500 mg) for 26-weeks. Outcome measures were 2.4 m gait-velocity, falls, fractures, death (Week-4), 25-OHD levels, quality-of-life measure (EuroQoL) and mortality at weeks-2, 4 and 26. RESULTS: Mean age of 218 participants was 83.9(7.2) years and 77.1 % were women. Baseline mean 25-OHD was 52.7(23.5)nmol/L, with higher levels at Week-2 (73 vs 66 nmol/L; p = .019) and Week-4 (83 vs 75 nmol/L; p = .030) in the Active-group, but not at Week-26. At week-4, there were no differences in 2.4 m gait-velocity (0.42 m/s vs 0.39 m/s, p = .490), fractures (2.7 % vs 2.8 %, p = .964) but Active participants reported less falls (6.3 % vs 21.1 %, χ(2) = 4.327; p = 0.024), with no significant reduction in deaths at week-4 (1 vs 3, p = 0.295), higher percentage reporting 'no pain or discomfort' (96.4 % vs 88.8 %, p = 0.037), and trended for higher EuroQoL-scores (p = 0.092) at week-26. One case of hypercalcemia at week-2 normalised by week-4. CONCLUSION: Among older people after hip fracture surgery, the REVITAHIP strategy is a safe and low cost method of improving vitamin-D levels, reducing falls and pain levels. TRIAL REGISTRATION: The protocol for this study is registered with the Australian New Zealand Clinical Trials Registry ANZCTRN ACTRN12610000392066 (Date of registration: 14/05/2010).


Assuntos
Conservadores da Densidade Óssea/administração & dosagem , Conservadores da Densidade Óssea/uso terapêutico , Colecalciferol/administração & dosagem , Colecalciferol/uso terapêutico , Fraturas do Quadril/tratamento farmacológico , Acidentes por Quedas/estatística & dados numéricos , Idoso , Idoso de 80 Anos ou mais , Austrália/epidemiologia , Conservadores da Densidade Óssea/efeitos adversos , Cálcio/administração & dosagem , Cálcio/sangue , Colecalciferol/efeitos adversos , Suplementos Nutricionais , Método Duplo-Cego , Feminino , Fraturas do Quadril/epidemiologia , Fraturas do Quadril/cirurgia , Humanos , Hipercalcemia/sangue , Hipercalcemia/induzido quimicamente , Masculino , Nova Zelândia/epidemiologia , Qualidade de Vida , Taxa de Sobrevida , Velocidade de Caminhada
16.
Aust Health Rev ; 39(4): 406-410, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25725502

RESUMO

OBJECTIVE: The aim of the present study was to assess whether the outdoor areas of residential aged care facilities used for a sunlight intervention trial had the design features that encouraged participants' use of these spaces. METHODS: The design principles recommended in the 'Vitamin D and the Built Environment in Victoria' guidelines were used to assess the outdoor spaces of residential aged care facilities that were used in a randomised controlled trial (RCT) of sunlight exposure. Attendance rates in the sunlight RCT were analysed in relation to global impression scores of the facilities using one-way analysis of variance. RESULTS: Thirty-six outdoor areas of 31 facilities were assessed. The facilities met the guidelines for sun exposure, and were generally safe and accessible. However, many lacked privacy, security and aesthetic appeal. Most of the outdoor spaces were not used for regularly scheduled activities. Attendance rates were higher in those facilities with the highest global impression scores compared with those with the lowest scores (F(2,367) = 3.262, P = 0.039). CONCLUSIONS: The physical environment of the outdoor areas of residential aged care facilities was associated with their use for sunlight exposure. Suitably designed or modified spaces have the potential to encourage their greater use, and residential aged care facilities should also plan regular activities in those areas. These measures can facilitate safe sun exposure, as well as physical activity and social interaction in older people.


Assuntos
Arquitetura de Instituições de Saúde , Instituição de Longa Permanência para Idosos , Luz Solar , Deficiência de Vitamina D/prevenção & controle , Idoso , Feminino , Humanos , Masculino , New South Wales
17.
Thorax ; 69(8): 766-7, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24482091

RESUMO

Pulmonary Langerhans cell histiocytosis (PLCH) is a rare interstitial lung disease of unknown aetiology. We aimed to characterise a UK-wide cohort of patients with PLCH and compare diagnostic and management methods in specialist and non-specialist centres. 106 cases (53 hospitals) identified. Complete data received in 67 cases (53.7% female, age 37.1±14.4 years). 96% current or ex-smokers. Treatment; smoking cessation (79%), corticosteroids (30.6%), cytotoxic therapy (26.9%) and lung transplant (6%). Patients at specialist centres received cytotoxic drugs more often (p=0.0001) and survival appeared higher. This dataset indicates a more even gender distribution than previously documented. It suggests variation in clinical management and outcomes achieved dependent on clinical experience.


Assuntos
Histiocitose de Células de Langerhans/terapia , Sistema de Registros , Corticosteroides/uso terapêutico , Adulto , Feminino , Histiocitose de Células de Langerhans/epidemiologia , Humanos , Transplante de Pulmão , Masculino , Fatores de Risco , Abandono do Hábito de Fumar , Taxa de Sobrevida , Reino Unido/epidemiologia
18.
BMC Cancer ; 14: 780, 2014 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-25343963

RESUMO

BACKGROUND: Patients with primary cutaneous melanomas that are ulcerated and >2 mm in thickness, >4 mm in thickness and those with nodal micrometastases at diagnosis, have few options for adjuvant treatment. Recent studies have suggested a role for vitamin D to delay melanoma recurrence and improve overall prognosis. METHODS/DESIGN: This is a pilot placebo-controlled randomised phase II trial to assess the feasibility, safety and toxicity of an oral loading dose of Vitamin D (500,000 IU) followed by an oral dose of 50,000 IU of Vitamin D monthly for 2 years in patients who have been treated for cutaneous melanoma by wide excision of the primary. Patients aged 18-79 years who have completed primary surgical treatment and have Stage IIb, IIc, IIIa (N1a, N2a) or IIIb (N1a, N2a) disease are eligible for randomisation 2:1 to active treatment or placebo. The primary endpoints are sufficiency of dose, adherence to study medication and safety of the drug. The secondary endpoints are participation and progression free survival. The study has been approved by the Ethics Review Committee (RPAH Zone) of the Sydney Local Health District, protocol number X09-0138. DISCUSSION: Effective, non-toxic adjuvant therapy for high risk primary melanoma is not currently available. Favorable outcomes of this phase II study will form the basis for a multi-centre phase III study to assess whether the addition of oral high-dose vitamin D therapy in patients who have completed primary treatment for melanoma and are at high risk of recurrence will: 1. prolong time to recurrence within 5 years 2. improve overall survival at 5 years and 3. be both safe and tolerable. 62 patients have been randomised since the study commenced in December 2010. Target accrual for the study has been met with 75 patients randomised between December 2010 and August 2014.The Mel-D trial is conducted by the Australia and New Zealand Melanoma Trials Group (ANZMTG 02.09) TRIAL REGISTRATION: Australia and New Zealand Clinical Trials Registry (ANZCTR) ACTRN12609000351213.


Assuntos
Protocolos Clínicos , Melanoma/tratamento farmacológico , Melanoma/patologia , Vitamina D/administração & dosagem , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Quimioterapia Adjuvante , Humanos , Recidiva Local de Neoplasia , Estadiamento de Neoplasias , Neoplasias Cutâneas , Melanoma Maligno Cutâneo
19.
BMC Geriatr ; 14: 101, 2014 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-25200552

RESUMO

BACKGROUND: Hypovitaminosis D is particularly common among older people with a proximal femoral (hip) fracture. There are currently no agreed strategies for vitamin D replenishment after hip fracture surgery. The REVITAHIP Study is a multisite, double-blinded randomized-controlled trial investigating the effects of an oral vitamin D loading dose on gait velocity after hip fracture surgery. We describe the baseline characteristics of participants, aiming to document hypovitaminosis D and its associations after hip fracture. METHODS: Participants, over 65, recruited within 7 days following hip fracture surgery from 3 Australia hospitals, were randomly allocated to receive a loading dose of vitamin D3 (250,000IU) or placebo, followed by oral maintenance vitamin D3/calcium (800 IU/500 mg) and the usual hip fracture rehabilitation pathway. Demographic and clinical data were collected, including surgical procedure, pre-fracture functional status, Mini Mental State Examination (MMSE) score, serum 25-hydroxyvitamin D (25-OHD), Verbal Rating Scale (VRS) for pain, grip strength and gait velocity. The associations of baseline 25-OHD levels with demographic and clinical data were assessed using Pearson's correlation, ANOVA and regression analyses. RESULTS: Two-hundred-and-eighteen people with hip fracture participated in the study. Mean age was 83.9+/-7.2 years, 77% were women and 82% lived in private homes. Fifty-six percent had a subcapital fracture. Mean comorbidity count was 3.13+/-2.0. Mean MMSE was 26.1+/-3.9. Forty-seven percent of participants had hypovitaminosis D (<50 nmol/L). Multivariate regression models demonstrated higher baseline vitamin D levels were significantly associated with higher premorbid Barthel index scores, lower post-operative VRS pain levels and use of vitamin D. CONCLUSION: This study cohort shared similar demographic characteristics and comorbidities with other cohorts of people with hip fracture, with the probable exception of less cognitive impairment. Hypovitaminosis D was not as prevalent as previously documented. Patients taking vitamin D supplements and with higher premorbid Barthel index, reflecting greater independence and activity, tended to have higher 25-OHD levels at baseline. Further, lower VRS pain ratings following surgery were associated with higher vitamin D levels. Such associations will need further investigation to determine causation. (ANZCTR number, ACTRN12610000392066). TRIAL REGISTRATION: The protocol for this study is registered with the Australian New Zealand Clinical Trials Registry ANZCTRN ACTRN12610000392066.


Assuntos
Fraturas do Quadril/tratamento farmacológico , Fraturas do Quadril/cirurgia , Vitamina D/administração & dosagem , Idoso , Idoso de 80 Anos ou mais , Estudos de Coortes , Estudos Transversais , Método Duplo-Cego , Feminino , Fraturas do Quadril/sangue , Humanos , Masculino , Efeito Placebo , Vitamina D/sangue , Deficiência de Vitamina D/sangue , Deficiência de Vitamina D/tratamento farmacológico
20.
Adv Exp Med Biol ; 810: 303-28, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25207373

RESUMO

Vitamin D is primarily produced by a photochemical reaction in skin, using the energy of ultraviolet B radiation. Ultraviolet radiation in sunlight is also responsible for several types of DNA damage, immunosuppression and photoaging. A number of adaptive responses are known to occur in skin to increasing UV exposure, including increased pigmentation, increased thickness of the cornified layer of skin and upregulation of DNA repair pathways. In addition to these known responses, there is now sufficient evidence to suggest that the local vitamin D system in skin, which includes local production of the active hormone, 1,25 dihydroxyvitamin D, together with metabolites of over-irradiation products, and vitamin D receptor(s), also provide an adaptive response to UV. The vitamin D system in skin reduces DNA damage, inflammation and photocarcinogenesis. Because vitamin D is made in skin, sun damage is less than it would be otherwise.


Assuntos
Carcinogênese/metabolismo , Pele/metabolismo , Vitamina D/análogos & derivados , Vitamina D/metabolismo , Animais , Carcinogênese/efeitos da radiação , Dano ao DNA , Reparo do DNA , Expressão Gênica , Humanos , Imunidade Inata/efeitos da radiação , Camundongos , Receptores de Calcitriol/genética , Receptores de Calcitriol/metabolismo , Transdução de Sinais , Pele/patologia , Pele/efeitos da radiação , Envelhecimento da Pele , Pigmentação da Pele/efeitos da radiação , Raios Ultravioleta
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