Vitamin D target proteins: function and regulation

Exploring the Role of Vitamin D, Vitamin D-Dependent Proteins, and Vitamin D Receptor Gene Variation in Lung Cancer Risk

Lung cancer has an unfavorable prognosis with a rate of low overall survival, caused by the difficulty of diagnosis in the early stages and resistance to therapy. In recent years, there have been new therapies that use specific molecular targets and are effective in increasing the survival chances of advanced cancer. Therefore, it is necessary to find more specific biomarkers that can identify early changes in carcinogenesis and allow the earliest possible treatment. Vitamin D (VD) plays an important role in immunity and carcinogenesis. Furthermore, the vitamin D receptor (VDR) regulates the expression of various genes involved in the physiological functions of the human organism. The genes encoding the VDR are extremely polymorphic and vary greatly between human populations. To date, there are significant associations between VDR polymorphism and several types of cancer, but the data on the involvement of VDR polymorphism in lung cancer are still conflicting. Therefore, in this review, our aim was to investigate the relationship between VDR single-nucleotide polymorphisms in humans and the degree of risk for developing lung cancer. The studies showcased different gene polymorphisms to be associated with an increased risk of lung cancer: TaqI, ApaI, BsmI, FokI, and Cdx2. In addition, there is a strong positive correlation between VD deficiency and lung cancer development. Still, due to a lack of awareness, the assessment of VD status and VDR polymorphism is rarely considered for the prediction of lung cancer evolution and their clinical applicability, despite the fact that studies have shown the highest risk for lung cancer given by TaqI gene polymorphisms and that VDR polymorphisms are associated with more aggressive cancer evolution.

Vitamin D3 mitigates type 2 diabetes induced by a high carbohydrate-high fat diet in rats: Role of the purinergic system

This study evaluated the effect of vitamin D3 (VIT D3) supplementation on the enzymatic activities and density of ectonucleoside triphosphate diphosphohydrolase (E-NTPDase), ecto-5-nucleotidase (E-5'-NT), adenosine deaminase (ADA), as well as the density of P2 × 7R, P2Y12R, A1R, A2AR receptors, IL-1β, and oxidative parameters in type 2 diabetic rats. Forty male Wistar rats were fed a high carbohydrate-high fat diet (HCHFD) and received an intraperitoneal injection containing a single dose of streptozotocin (STZ, 35 mg/kg). Animals were divided into four groups: 1) control; 2) control/VIT D3 12 µg/kg; 3) diabetic; and 4) diabetic/VIT D3 12 µg/kg. Results show that VIT D3 reduced blood glucose, ATP hydrolysis, ADA activity, P2Y12R density (platelets), as well as ATP, ADP, and AMP hydrolysis and ADA activity (synaptosomes). Moreover, VIT D3 increased insulin levels and AMP hydrolysis (platelets) and improved antioxidant defense. Therefore, we suggest that VIT D3 treatment modulates hyperglycemia-induced changes via purinergic enzymes and receptor expression, consequently attenuating insulin homeostasis dysregulation in the diabetic state.

Use of lactulose as a prebiotic in laying hens: its effect on growth, egg production, egg quality, blood biochemistry, digestive enzymes, gene expression and intestinal morphology

BACKGROUND

The rising popularity of eggs as an alternative source of protein to meat has led to significant increase in egg consumption over the past decade. To meet the increasing demand for eggs, poultry farmers have used antibiotics to treat infections and, to some extent, promote growth and egg production in raising layer. However, the emergence and global spread of antibiotic resistant bacteria has now necessitated antibiotic-free poultry farming. As alternatives to antibiotics, prebiotics are feed additives that can be used to improve the growth and laying performance of poultry which positively impacts their performance and general health. In this study we evaluated the effect of lactulose, formulated as Vetelact, on body weight, egg production, egg quality, blood biochemical parameters and expression of genes associated with reproductive performance in laying hens.

RESULTS

Vetelact supplementation improved egg weight, egg production as well as egg quality. Following Vetalact supplementation, the levels of total bilirubin, total protein, globulin and phosphorus were increased, while the activities of alkaline phosphatase and lipase enzymes were increased compared to control. Vetelact at 0.10 ml/kg body weight upregulated OCX-36, OVAL, CALB1, OC-116, OCX-32 and IL8 transcripts while downregulating the transcription of Gal-10, PENK and AvBD9. At this optimal inclusion rate of Vetalect, histomorphologic analyses of intestinal tissue showed increased villi length with more goblet cell distribution and obvious mucus covering a surface, increase in the depth of intestinal crypts produce digestive enzymes, as well as more developed muscle layer that promote improved nutrient absorption.

CONCLUSION

Vetelact at a dose of 0.10 ml/ kg body weight was effective in improving productive performance of laying hens. Adding lactulose (0.10 ml/ kg body weight) to layer diet is recommended to promote growth and improve egg laying performance in antibiotics-free poultry production.

Calbindin Has a Potential Spatiotemporal Correlation with Proliferation and Apoptosis in the Postnatal Rat Kidney

The protein calbindin-D28k modulates calcium reabsorption in the kidney. Here, we aimed to study the influence of proliferation and apoptosis in different compartments of the kidney on the developmental function of calbindin. Using immunohistochemistry, we investigated the postnatal development of rats' kidneys by using calbindin, proliferative cell nuclear antigen (PCNA), and apoptotic single-stranded DNA (ssDNA). In the neonatal stage (1-day and 1-week-old rats), calbindin showed a positive reaction in the distal convoluted tubule (DCT), a short nephron segment between the macula densa, collecting ducts, and tubules. Moreover, the localization of calbindin was restricted to immature nephrons and mesenchymal tissues. Furthermore, PCNA immunoreactivity was moderate in early-developed podocytes with no reactivity in other renal tubules. The ssDNA immunoreactivity was moderate in the undifferentiated nephron. Then, in the mature stage (3 and 6 weeks old), there was an intense calbindin reaction in DCT but a moderate reaction to PCNA and ssDNA in podocytes. A more intense calbindin reactivity was found in the adult stage (2- and 3-month-old rats) in DCT and collecting tubules. Therefore, in this study, calbindin localization showed an inverse relationship with PCNA and ssDNA of the nephron compartments, which might reflect the efficiency of bone-building and muscle contraction during animal development.

Targeting Autophagy for Developing New Therapeutic Strategy in Intervertebral Disc Degeneration

Intervertebral disc degeneration (IVDD) is a prevalent cause of low back pain. IVDD is characterized by abnormal expression of extracellular matrix components such as collagen and aggrecan. In addition, it results in dysfunctional growth, senescence, and death of intervertebral cells. The biological pathways involved in the development and progression of IVDD are not fully understood. Therefore, a better understanding of the molecular mechanisms underlying IVDD could aid in the development of strategies for prevention and treatment. Autophagy is a cellular process that removes damaged proteins and dysfunctional organelles, and its dysfunction is linked to a variety of diseases, including IVDD and osteoarthritis. In this review, we describe recent research findings on the role of autophagy in IVDD pathogenesis and highlight autophagy-targeting molecules which can be exploited to treat IVDD. Many studies exhibit that autophagy protects against and postpones disc degeneration. Further research is needed to determine whether autophagy is required for cell integrity in intervertebral discs and to establish autophagy as a viable therapeutic target for IVDD.

Vitamin D3 intake as modulator for the early biomarkers of myocardial tissue injury in diabetic hyperlipidaemic rats

CONTEXT

Myocardial cell death occurs within hours following the onset of myocardial ischaemia and its chief cause is atherosclerosis. There is a link between vitamin D3 deficiency and many cardiovascular risk factors.

OBJECTIVE

This study compared the effect of vitamin D3 on early biomarkers of myocardial injury, to that of atorvastatin.

METHODS

Diabetic hyperlipidaemia was induced in Wistar rats, which were divided into 3 groups: diabetic hyperlipidaemic control, diabetic hyperlipidaemic rats treated with atorvastatin and diabetic hyperlipidaemic rats treated with vitamin D3. Blood glucose, glycated haemoglobin and lipid profile were evaluated. Markers of myocardial injury were examined including cardiac troponin, heart fatty acid binding protein (HFABP) and C-terminal pro-endothelin-1 (CT-pro-ET-1).

RESULTS

Vitamin D3 and atorvastatin intake improved lipid profile and glucose homeostasis, and reduced levels of predictive biomarkers of myocardial injury.

CONCLUSION

Vitamin D3 can be used in a suitable dose as a safe and protective candidate against myocardial injury.

A Naringin- and Icariin-Contained Herbal Formula, Gushukang, Ameliorated Aged Osteoporosis of Aged Mice with High Calcium Intake

Traditional herbal formula Gushukang (GSK) was clinically applied to treat primary osteoporosis and showed osteoprotective effect in ovariectomized rodent animals and regulatory action on calcium transporters. This study aimed to determine if GSK could ameliorate aged osteoporosis by modulating serum level of calciotropic hormones and improving calcium balance. 18-month-old male mice were orally administered with either GSK (0.38[Formula: see text]g/kg body weight) or calcitriol (1[Formula: see text][Formula: see text]g/kg body weight) combined with high calcium diet (HCD, 1.2% Ca) for 60 days. The aged mice fed with normal calcium diet (NCD, 0.6% Ca) were a negative control. Trabecular bone and cortical bone properties as well as calcium balance were determined. Treatment with GSK significantly increased 25(OH)D and 1,25-(OH)₂D levels in serum, moreover, it markedly attenuated trabecular bone micro-architectural deteriorations and elevated trabecular bone mass as well as strengthened cortical bone mechanical properties shown by the increase in maximal bending load and elastic modulus. Calcium balance, including urinary Ca excretion, fecal Ca level and net calcium retention, was remarkably improved by GSK, which up-regulated TRPV6 expression in duodenum and TRPV5 expression in kidney and down-regulated claudin-14 expression in duodenum and kidney. Additionally, 1-OHase and 24-OHase expression was significantly decreased (vs. NCD group) and increased (vs. HCD group), respectively, in kidney of GSK- and calcitriol-treated mice. Taken together, this study demonstrated the ameliorative effects of Gushukang on aged osteoporosis by effectively stimulating vitamin D production and improving calcium balance of aged mice with high dietary calcium supplement.

Congenital Unilateral Renal Aplasia in a Cynomolgus Monkey (Macaca fascicularis) With Investigation Into Potential Pathogenesis

We describe and characterize unilateral renal aplasia in a cynomolgus monkey (Macaca fascicularis) from a chronic toxicology study adding to the limited histopathology reports of congenital renal anomalies in macaques. In the current case, the affected kidney was macroscopically small and characterized microscopically by a thin cortex with an underdeveloped medulla and an absent papilla. The remnant medulla lacked a corticomedullary junction and contained only a few irregular collecting duct-like structures. The cortex had extensive interstitial mature collagen deposition with fibromuscular collar formation around Bowman's capsules. Due to parenchymal collapse, mature glomeruli were condensed together with occasional atrophic and sclerotic glomeruli. The majority of the cortical tubules were poorly differentiated with only small islands of fully developed cortical tubules present. Histochemical and immunohistochemical stains were utilized to demonstrate key diagnostic features of this congenital defect, to assist with differentiating it from renal dysplasia, and to provide potential mechanistic pathways. Immunostaining (S100, paired box gene 2 [PAX2], aquaporins) of the medulla was compatible with incomplete maturation associated with aplasia, while the immunostaining profile for the cortex (vimentin, calbindin, PAX2-positive cortical tubules, and smooth muscle actin-positive fibromuscular collars) was most compatible with dedifferentiation secondary to degenerative changes.

Regulation of Expression of CEBP Genes by Variably Expressed Vitamin D Receptor and Retinoic Acid Receptor α in Human Acute Myeloid Leukemia Cell Lines

All-trans-retinoic acid (ATRA) and 1α,25-dihydroxyvitamin D (1,25D) are potent inducers of differentiation of myeloid leukemia cells. During myeloid differentiation specific transcription factors are expressed at crucial developmental stages. However, precise mechanism controlling the diversification of myeloid progenitors is largely unknown, CCAAT/enhancer-binding protein (C/EBP) transcription factors have been characterized as key regulators of the development and function of the myeloid system. Past data point at functional redundancy among C/EBP family members during myeloid differentiation. In this study, we show that in acute myeloid leukemia (AML) cells, high expression of vitamin D receptor gene (VDR) is needed for strong and sustained upregulation of CEBPB gene, while the moderate expression of VDR is sufficient for upregulation of CEBPD in response to 1,25D. The high expression level of the gene encoding for retinoic acid receptor α (RARA) allows for high and sustained expression of CEBPB, which becomes decreased along with a decrease of RARA expression. Expression of CEBPB induced by ATRA is accompanied by upregulated expression of CEBPE with similar kinetics. Our results suggest that CEBPB is the major VDR and RARA-responsive gene among the CEBP family, necessary for expression of genes connected with myeloid functions.

In vitro and clinical data analysis of Osteopontin as a prognostic indicator in colorectal cancer

Osteopontin (OPN) has been shown to promote colorectal cancer (CRC) progression; however, the mechanism of OPN-induced CRC progression is largely unknown. In this study, we found that OPN overexpression led to enhanced anchorage-independent growth, cell migration and invasion in KRAS gene mutant cells but to a lesser extent in KRAS wild-type cells. OPN overexpression also induced PI3K signalling, expression of Snail and Matrix metallopeptidase 9 (MMP9), and suppressed the expression of E-cadherin in KRAS mutant cells. In human CRC specimens, a high-level expression of OPN significantly predicted poorer survival in CRC patients and OPN expression was positively correlated with MMP9 expression, and negatively correlated with E-cadherin expression. Furthermore, we have found that 15 genes were co-upregulated in OPN highly expression CRC and a list of candidate drugs that may have potential to reverse the secreted phosphoprotein 1 (SPP1) gene signature by connectivity mapping. In summary, OPN is a potential prognostic indicator and therapeutic target for colon cancer.

Vitamin D and pancreas: The role of sunshine vitamin in the pathogenesis of diabetes mellitus and pancreatic cancer

Increasing evidence suggests that vitamin D exerts multiple effects beyond bone and calcium metabolism. Vitamin D seems to play a role in pancreatic disease, including type 1 and type 2 diabetes mellitus as well as pancreatic cancer. Vitamin D's immune-modulatory action suggests that it could help prevent type 1 diabetes. In type 2 diabetes, vitamin D may influence β-cell function, insulin sensitivity, and systematic inflammation-all characteristic pathways of that disease. Data from observational studies correlated vitamin D deficiency with risk of type 1 and type 2 diabetes. Prospective and ecological studies of pancreatic cancer incidence generally support a beneficial effect of higher 25-hydroxyvitamin D concentration as well as inverse correlations between UVB dose or exposure and incidence and/or mortality rate of pancreatic cancer. This review discusses the literature regarding vitamin D's role in risk of diabetes and pancreatic cancer. The results to date generally satisfy Hill's criteria for causality regarding vitamin D and incidence of these pancreatic diseases. However, large randomized, blinded, prospective studies are required to more fully evaluate the potential therapeutic role of vitamin D in preventing pancreatic diseases.

Vitamin D: Musculoskeletal health

Perhaps the role of Vitamin D supplementation has been most exhaustively studied in calcium absorption, skeletal wellbeing, muscular potency, balance and risk of falling. Nonetheless, new data has emerged and the recent research on sarcopenia makes the topic increasingly interesting. Given the socioeconomic burden of the musculoskeletal consequences of hypovitaminosis D it is vital to keep abreast with the latest literature in the field. The recommended Vitamin D supplementation dose should suffice to increase the serum 25 hydroxyvitamin D level to 30 ng/mL (75 nmol/L) and this level should be optimally maintained with a maintenance dose, particularly for those diagnosed with osteoporosis.

The pathogenesis of proventricular dilatation disease

Bornaviruses cause neurologic diseases in several species of birds, especially parrots, waterfowl and finches. The characteristic lesions observed in these birds include encephalitis and gross dilatation of the anterior stomach — the proventriculus. The disease is thus known as proventricular dilatation disease (PDD). PDD is characterized by extreme proventricular dilatation, blockage of the passage of digesta and consequent death by starvation. There are few clinical resemblances between this and the bornaviral encephalitides observed in mammals. Nevertheless, there are common virus-induced pathogenic pathways shared across this disease spectrum that are explored in this review. Additionally, a review of the literature relating to gastroparesis in humans and the control of gastric mobility in mammals and birds points to several plausible mechanisms by which bornaviral infection may result in extreme proventricular dilatation.

Deterioration of eggshell quality is related to calbindin in laying hens infected with velogenic genotype VIId Newcastle disease virus

The aim of this study was to determine the mechanism by which Newcastle disease virus (NDV) affects eggshell quality. Thirty-week-old specific pathogen free (SPF) egg-laying hens were inoculated with the velogenic genotype VIId NDV strain (infected group) or with inoculating media without virus (control group) by combined intraocular and intranasal routes. The levels of CaBP-D28k mRNA expression in the uterus, a gene related to eggshell quality, were examined by quantitative reverse transcriptase polymerase chain reaction (RT-PCR). The quality of eggshells was analyzed by scanning electron microscopy (SEM). The infected group showed a marked decline in egg production when compared to the control group. The NDV antigen was found more abundantly in the glandular epithelium of the infected hens' uteri from 1 to 15 d post-inoculation (dpi). The levels of CaBP-D28k mRNA expression in the uteri of infected hens were significantly lower than in the control hens from 3 to 15 dpi (P < 0.05). The changes in the Ca concentrations in the eggshells were consistent with the expression of CaBP-D28k mRNA in the infected hens. Ultrastructural examination of eggshells showed significantly reduced shell thickness in the infected hens from 1 to 15 dpi (P < 0.05). Furthermore, obvious changes in the structure of the external shell surface and shell membrane were detected in the infected hens compared with the control hens. In conclusion, the current study confirmed that velogenic genotype VIId NDV infection is associated with the deterioration of the eggshell quality of the laying hens.

Potential Contributions of the Tobacco Nicotine-Derived Nitrosamine Ketone to White Matter Molecular Pathology in Fetal Alcohol Spectrum Disorder

Background

Fetal alcohol spectrum disorder (FASD) is associated with long-term deficits in cognitive and motor functions. Previous studies linked neurodevelopmental abnormalities to increased oxidative stress and white matter hypotrophy. However, similar effects occur with low-dose nitrosamine exposures, alcohol abuse correlates with cigarette smoking, and tobacco smoke contains tobacco-specific nitrosamines, including NNK.

Hypothesis

Tobacco smoke exposure is a co-factor in FASD.

Design

Long Evans rat pups were i.p. administered ethanol (2 g/kg) on postnatal days (P) 2, 4, 6 and/or NNK (2 mg/kg) on P3, P5, and P7 to simulate third trimester human exposures. Oligodendroglial myelin-associated, neuroglial, and relevant transcription factor mRNA transcripts were measured using targeted PCR arrays.

Results

Ethanol and NNK differentially altered the expression of immature and mature oligodendroglial, neuronal and astrocytic structural and plasticity-associated, and various transcription factor genes. NNK’s effects were broader and more pronounced than ethanol’s, and additive or synergistic effects of dual exposures impacted expression of all four categories of genes investigated.

Conclusion

Developmental exposures to alcohol and NNK (via tobacco smoke) contribute to sustained abnormalities in brain white matter structure and function via distinct but overlapping alterations in the expression of genes that regulate oligodendrocyte survival, maturation and function, neuroglial structural integrity, and synaptic plasticity. The results support the hypothesis that smoking may contribute to brain abnormalities associated with FASD.

Deterioration of eggshell quality in laying hens experimentally infected with H9N2 avian influenza virus

This study aimed to determine the mechanism by which H9N2 avian influenza virus (AIV) affects eggshell quality. Thirty-week-old specific pathogen free egg-laying hens were inoculated with the chicken-origin H9N2 AIV strain (A/Chicken/shaanxi/01/2011) or with inoculating media without virus by combined intraocular and intranasal routes. The time course for the appearance of viral antigen and tissue lesions in the oviduct was coincident with the adverse changes in egg production in the infected hens. The viral loads of AIV have a close correlation with the changes in the uterus CaBP-D28k mRNA expression as well as the Ca concentrations in the eggshells in the infected hens from 1 to 7 days post inoculation (dpi). Ultrastructural examination of eggshells showed significantly decreased shell thickness in the infected hens from 1 to 5 dpi (P < 0.05). Furthermore, obvious changes in the structure of the external shell surface and shell membrane were detected in the infected hens from 1 to 5 dpi as compared with the control hens. In conclusion, this study confirmed that H9N2 AIV strain (A/Chicken/shaanxi/01/2011) infection is associated with severe lesions of the uterus and abnormal expression of CaBP-D28k mRNA in the uteri of the infected hens. The change of CaBP-D28k mRNA expression may contribute to the deterioration of the eggshell quality of the laying hens infected with AIV. It is noteworthy that the pathogenicity of H9N2 AIV strains may vary depending on the virus strain and host preference.

Biological chemistry and functionality of protein sulfenic acids and related thiol modifications

Selective modification of proteins at cysteine residues by reactive oxygen, nitrogen or sulfur species formed under physiological and pathological states is emerging as a critical regulator of protein activity impacting cellular function. This review focuses primarily on protein sulfenylation (-SOH), a metastable reversible modification connecting reduced cysteine thiols to many products of cysteine oxidation. An overview is first provided on the chemistry principles underlining synthesis, stability and reactivity of sulfenic acids in model compounds and proteins, followed by a brief description of analytical methods currently employed to characterize these oxidative species. The following chapters present a selection of redox-regulated proteins for which the -SOH formation was experimentally confirmed and linked to protein function. These chapters are organized based on the participation of these proteins in the regulation of signaling, metabolism and epigenetics. The last chapter discusses the therapeutic implications of altered redox microenvironment and protein oxidation in disease.

Role Of Vitamin D And Adipose Tissue Hormones In Women With Reproductive Disorders

The role of vitamin D beyond that it plays in bone metabolism and calcium homeostasis has been lately quite emphasized. In this respect, vitamin D deficiency has been associated with higher risk of cardiovascular disease, metabolic syndrome, and reproductive disorders. Growing evidence has suggested that vitamin D deficiency is implicated in the pathogenesis of insulin resistance and the development of metabolic disorders in the polycystic ovary syndrome. The goal of the review is to present contemporary concepts of the relationship between hormones affecting the metabolic body status, serum vitamin D levels and the reproductive function.

Differential Contributions of Alcohol and Nicotine-Derived Nitrosamine Ketone (NNK) to White Matter Pathology in the Adolescent Rat Brain

AIM

Epidemiologic studies have demonstrated high rates of smoking among alcoholics, and neuroimaging studies have detected white matter atrophy and degeneration in both smokers and individuals with alcohol-related brain disease (ARBD). These findings suggest that tobacco smoke exposure may be a co-factor in ARBD. The present study examines the differential and additive effects of tobacco-specific nitrosamine (NNK) and ethanol exposures on the structural and functional integrity of white matter in an experimental model.

METHODS

Adolescent Long Evans rats were fed liquid diets containing 0 or 26% ethanol for 8 weeks. In weeks 3-8, rats were treated with nicotine-derived nitrosamine ketone (NNK) (2 mg/kg, 3×/week) or saline by i.p. injection. In weeks 7-8, the ethanol group was binge-administered ethanol (2 g/kg; 3×/week).

RESULTS

Ethanol, NNK and ethanol + NNK caused striking degenerative abnormalities in white matter myelin and axons, with accompanying reductions in myelin-associated glycoprotein expression. Quantitative RT-PCR targeted array and heatmap analyses demonstrated that ethanol modestly increased, whereas ethanol + NNK sharply increased expression of immature and mature oligodendroglial genes, and that NNK increased immature but inhibited mature oligodendroglial genes. In addition, NNK modulated expression of neuroglial genes in favor of growth cone collapse and synaptic disconnection. Ethanol- and NNK-associated increases in FOXO1, FOXO4 and NKX2-2 transcription factor gene expression could reflect compensatory responses to brain insulin resistance in this model.

CONCLUSION

Alcohol and tobacco exposures promote ARBD by impairing myelin synthesis, maturation and integrity via distinct but overlapping mechanisms. Public health measures to reduce ARBD should target both alcohol and tobacco abuses.

Association of collagen I, IX and vitamin D receptor gene polymorphisms with radiological severity of intervertebral disc degeneration in Southern European Ancestor

PURPOSE

Several genomic loci have been previously found to be associated with intervertebral disc degeneration, so far. Data are mostly derived from northern European countries whereas data derived from Southern European Ancestor are limited. This study aimed to evaluate the association between radiological disease severity of lumbar disc degeneration and certain genetic loci in a sample of participants from Southern Europe.

METHODS

Seventy-five patients with mild to severe lumbar disc degeneration and 25 healthy controls were enrolled into the study. In each subject, each lumbar intervertebral disc was separately examined to obtain a total radiological score for disease severity. In addition, single-nucleotide polymorphisms of predefined genetic samples were analyzed in all participants: COL1A1 Sp1, COL9a2 Trp2, COL9a3 Trp3, and VDR TaqI.

RESULTS

Degeneration scores were significantly worse in cases with COL1A1 Sp1, COL9a3 Trp3, and VDR TaqI mutations; however, COL9a2 Trp2 mutation was not associated with a difference in the severity of disc degeneration. In addition, subjects with mutation in more than one gene sample (n = 20) had significantly worse degeneration scores than the remaining study participants (n = 80) (17.70 ± 2.72 vs. 21.81 ± 1.81, p < 0.001).

CONCLUSION

Single-nucleotide polymorphisms occurring in COL1A1, COL9a3 and VDR genes seem to be associated with the development of lumbar disc degeneration in this cohort, possibly with even more pronounced association when multiple mutations are present in the same individual. By further prospective twin studies in associated genes and analyses of their relationship with environmental factors in an internationally sampled large cohort will make a more clear-minded conclusion about their association with disc degeneration, which would yield better appreciation and clinical planning of some predisposed people for these pathologies.

Inhibition of West Nile virus by calbindin-D28k

Evidence indicates that West Nile virus (WNV) employs Ca²⁺ influx for its replication. Moreover, calcium buffer proteins, such as calbindin D28k (CB-D28k), may play an important role mitigating cellular destruction due to disease processes, and more specifically, in some neurological diseases. We addressed the hypothesis that CB-D28k inhibits WNV replication in cell culture and infected rodents. WNV envelope immunoreactivity (ir) was not readily co-localized with CB-D28k ir in WNV-infected Vero 76 or motor neuron-like NSC34 cells that were either stably or transiently transfected with plasmids coding for CB-D28k gene. This was confirmed in cultured cells fixed on glass coverslips and by flow cytometry. Moreover, WNV infectious titers were reduced in CB-D28k-transfected cells. As in cell culture studies, WNV env ir was not co-localized with CB-D28k ir in the cortex of an infected WNV hamster, or in the hippocampus of an infected mouse. Motor neurons in the spinal cord typically do not express CB-D28k and are susceptible to WNV infection. Yet, CB-D28k was detected in the surviving motor neurons after the initial phase of WNV infection in hamsters. These data suggested that induction of CB-D28k elicit a neuroprotective response to WNV infection.

Loss of Calbindin immunoreactivity in the dentate gyrus distinguishes Alzheimer's disease from other neurodegenerative dementias

Calbindin (Cb) is one of the major Ca(2+) binding proteins exhibiting neuromodulatory functions such as long-term potentiation (LTP), synaptic plasticity, and memory functions. It is expressed in hippocampal interneurons, pyramidal cells and granule cells of the dentate gyrus (DGCs). Cb mRNA levels remain stable during normal ageing, but decrease in Alzheimer's, Huntington, and Parkinson's disease. A recent study suggested a link between Aβ-induced Alzheimer's disease (AD)-related cognitive deficits and neuronal depletion of Cb. To evaluate whether this is specific for AD, we performed a comparative study of Cb immunoreactivity of DGCs in cases with AD-related neuropathologic change (49), grouped according to the stages of Braak and Braak, BB), Creutzfeldt-Jakob-disease (16), FTLD-tau Pick's disease type (PiD; 5), argyrophilic grain disease (8), and FTLD-TDP types A and B (6). The group of AD cases with BB stages V and VI showed the highest proportion of Cb negative cells in the DGC when compared to all other groups except PiD. The ratio of negative cells correlated significantly with the BB stages. While the total number of DGCs decreased with age in our series, loss of Cb immunoreactivity was shown to be age-dependent only in PiD and FTLD-TDP. We conclude, that late stage AD-neuropathologic change (BB V and VI stages) associates with significantly higher ratios of Cb negative DGCs and this correlates with advanced BB stage. This might suggest an accumulative effect of an epilepsy-like pathway on the Cb expression or the direct influence of local pathological protein deposits on the DGCs.

Focal cerebral ischemic injury decreases calbindin expression in brain tissue and HT22 cells

Calbindin is a calcium binding protein that controls intracellular calcium levels and has a neuroprotective function against apoptotic stimuli. We investigated the expression of calbindin in ischemic brain injury. Focal cerebral ischemia was induced in male rats by middle cerebral artery occlusion (MCAO) and cerebral cortices were collected 24 h after MCAO. Cerebral ischemia significantly increased infarct volume. RT-PCR and Western blot analyses showed that MCAO injury induced a decrease of calbindin expression. Moreover, immunohistochemical staining showed that the number of calbindin-positive cells decreased in ischemic regions of MCAO-operated animals. In cultured hippocampal-derived cell lines, glutamate exposure increased intracellular Ca²⁺ concentrations and decreased calbindin expression. Taken together, both in vivo and in vitro results demonstrated decreases of calbindin after neuronal cell injury. These results suggest that decreases of calbindin in ischemic brain injury contribute to neuronal cell death.

Villin promoter-mediated transgenic expression of transient receptor potential cation channel, subfamily V, member 6 (TRPV6) increases intestinal calcium absorption in wild-type and vitamin D receptor knockout mice

Transient receptor potential cation channel, subfamily V, member 6 (TRPV6) is an apical membrane calcium (Ca) channel in the small intestine proposed to be essential for vitamin D-regulated intestinal Ca absorption. Recent studies have challenged the proposed role for TRPV6 in Ca absorption. We directly tested intestinal TRPV6 function in Ca and bone metabolism in wild-type (WT) and vitamin D receptor knockout (VDRKO) mice. TRPV6 transgenic mice (TG) were made with intestinal epithelium-specific expression of a 3X Flag-tagged human TRPV6 protein. TG and VDRKO mice were crossed to make TG-VDRKO mice. Ca and bone metabolism was examined in WT, TG, VDRKO, and TG-VDRKO mice. TG mice developed hypercalcemia and soft tissue calcification on a chow diet. In TG mice fed a 0.25% Ca diet, Ca absorption was more than three-fold higher and femur bone mineral density (BMD) was 26% higher than WT. Renal 1α hydroxylase (CYP27B1) mRNA and intestinal expression of the natural mouse TRPV6 gene were reduced to <10% of WT but small intestine calbindin-D(9k) expression was elevated >15 times in TG mice. TG-VDRKO mice had high Ca absorption that prevented the low serum Ca, high renal CYP27B1 mRNA, low BMD, and abnormal bone microarchitecture seen in VDRKO mice. In addition, small intestinal calbindin D(9K) mRNA and protein levels were elevated in TG-VDRKO. Transgenic TRPV6 expression in intestine is sufficient to increase Ca absorption and bone density, even in VDRKO mice. VDR-independent upregulation of intestinal calbindin D(9k) in TG-VDRKO suggests this protein may buffer intracellular Ca during Ca absorption. © 2012 American Society for Bone and Mineral Research.

Relevance of vitamin D in reproduction

The steroid hormone vitamin D is historically recognized for its relevance to bone health and calcium homeostasis. Recent years have witnessed a shift in focus to non-skeletal benefits of vitamin D; in this latter context, an accruing body of literature attests to a relevance of vitamin D to reproductive physiology. This article reviews the existing data about the diverse and previously underappreciated roles for vitamin D in reproductive health. A large body of available literature suggests that vitamin D deficiency may be detrimental to reproductive biology. However, given that our appreciation of vitamin D's role in reproductive physiology is almost entirely shaped by 'associative' studies and that data based on prospective interventional trials are limited, these concepts remain predominantly conjectural. Exact mechanisms whereby vitamin D may participate in the regulation of reproductive physiology remain far from clear. This review underscores a need for appropriately designed intervention trials to address the existing knowledge gaps and to delineate the specific roles of vitamin D signaling in reproductive biology.

Identification of uterine ion transporters for mineralisation precursors of the avian eggshell

BACKGROUND

In Gallus gallus, eggshell formation takes place daily in the hen uterus and requires large amounts of the ionic precursors for calcium carbonate (CaCO3). Both elements (Ca2+, HCO3-) are supplied by the blood via trans-epithelial transport. Our aims were to identify genes coding for ion transporters that are upregulated in the uterine portion of the oviduct during eggshell calcification, compared to other tissues and other physiological states, and incorporate these proteins into a general model for mineral transfer across the tubular gland cells during eggshell formation.

RESULTS

A total of 37 candidate ion transport genes were selected from our database of overexpressed uterine genes associated with eggshell calcification, and by analogy with mammalian transporters. Their uterine expression was compared by qRTPCR in the presence and absence of eggshell formation, and with relative expression levels in magnum (low Ca2+/HCO3- movement) and duodenum (high rates of Ca2+/HCO3- trans-epithelial transfer). We identified overexpression of eleven genes related to calcium movement: the TRPV6 Ca2+ channel (basolateral uptake of Ca2+), 28 kDa calbindin (intracellular Ca2+ buffering), the endoplasmic reticulum type 2 and 3 Ca2+ pumps (ER uptake), and the inositol trisphosphate receptors type 1, 2 and 3 (ER release). Ca2+ movement across the apical membrane likely involves membrane Ca2+ pumps and Ca2+/Na+ exchangers. Our data suggests that Na+ transport involved the SCNN1 channel and the Na+/Ca2+ exchangers SLC8A1, 3 for cell uptake, the Na+/K+ ATPase for cell output. K+ uptake resulted from the Na+/K+ ATPase, and its output from the K+ channels (KCNJ2, 15, 16 and KCNMA1).We propose that the HCO3- is mainly produced from CO2 by the carbonic anhydrase 2 (CA2) and that HCO3- is secreted through the HCO3-/Cl- exchanger SLC26A9. HCO3- synthesis and precipitation with Ca2+ produce two H+. Protons are absorbed via the membrane's Ca2+ pumps ATP2B1, 2 in the apical membrane and the vacuolar (H+)-atpases at the basolateral level. Our model incorporate Cl- ions which are absorbed by the HCO3-/Cl- exchanger SLC26A9 and by Cl- channels (CLCN2, CFTR) and might be extruded by Cl-/H+ exchanger (CLCN5), but also by Na+ K+ 2 Cl- and K+ Cl- cotransporters.

CONCLUSIONS

Our Gallus gallus uterine model proposes a large list of ion transfer proteins supplying Ca2+ and HCO3- and maintaining cellular ionic homeostasis. This avian model should contribute towards understanding the mechanisms and regulation for ionic precursors of CaCO3, and provide insight in other species where epithelia transport large amount of calcium or bicarbonate.

Effect of 1, 25(OH)₂ vitamin D₃ on glucose homeostasis and DNA damage in type 2 diabetic mice

AIMS

The purpose of the study was to examine the effect of 1, 25(OH)₂ Vitamin D₃ supplementation on type 2 diabetic (T2DM) mice.

MATERIALS AND METHODS

A total of 24 mice were taken and divided into three groups of control; diabetic and diabetic + vitamin D supplemented ones. Serum calcium level, fasting blood glucose level (FBG), hexokinase activity, glucose-6-phosphatse and fructose 1,6 bisphosphatase activity were measured to establish a relevant correlation between vitamin D supplementation and hyperglycemia in T2DM.

RESULTS

There occurred an increase in FBG levels (250 ± 0.41 mg/dl) and a significant decrease in serum calcium levels in the diabetic group (8.63 ± 0.40 mg/ml) both of which reached near control levels on vitamin D₃ supplementation. The activity of the glucose metabolic enzymes was also assayed in diabetic group and was found to be deviated from control group; hexokinase (0.0241 ± 0.014 μg/mg/ml) FBPase (0.433 ± 0.002 μg/mg/ml) and G6Pase (0.918 ± 0.02 μg/mg/ml). However, the activity of these enzymes returned to near control values with hexokinase activity reaching 0.717 ± 0.003 μg/mg/ml on vitamin D₃ supplementation. The FBPase and G6Pase activities were decreased to 0.2733 ± 0.008 μg/mg/ml and G6Pase 0.71 ± 0.01 μg/mg/ml respectively. In addition to enzymatic analysis, the organs of all three groups of mice were subjected to comet assay. The diabetic group receiving vitamin D supplementation showed a marked recovery exhibiting shorter tail length both in liver (21.80 ± 2.40 μm) and pancreatic cells (19.25 ± 1.90 μm) as compared to the diabetic group exhibiting a tail length of 30.41 ± 2.50 μm and 32.45 ± 2.87 μm in liver and pancreatic cells respectively.

CONCLUSION

The present study shows that vitamin D₃ supplementation is positively correlated with decrease in blood glucose level and serum calcium level in fasting condition. This suggests a positive influence of vitamin D on glucose homeostasis. Besides, the activity of various glucose metabolic enzymes (hexokinase, FBPase and G6Pase) as shown by our results and the remarkable shortening of DNA tail length in vitamin D supplemented diabetic group as compared to diabetic group without supplementation further support the idea that vitamin D supplementation might be an add-on therapy for patients with T2DM.

Peripubertal vitamin D(3) deficiency delays puberty and disrupts the estrous cycle in adult female mice

The mechanism(s) by which vitamin D(3) regulates female reproduction is minimally understood. We tested the hypothesis that peripubertal vitamin D(3) deficiency disrupts hypothalamic-pituitary-ovarian physiology. To test this hypothesis, we used wild-type mice and Cyp27b1 (the rate-limiting enzyme in the synthesis of 1,25-dihydroxyvitamin D(3)) null mice to study the effect of vitamin D(3) deficiency on puberty and reproductive physiology. At the time of weaning, mice were randomized to a vitamin D(3)-replete or -deficient diet supplemented with calcium. We assessed the age of vaginal opening and first estrus (puberty markers), gonadotropin levels, ovarian histology, ovarian responsiveness to exogenous gonadotropins, and estrous cyclicity. Peripubertal vitamin D(3) deficiency significantly delayed vaginal opening without affecting the number of GnRH-immunopositive neurons or estradiol-negative feedback on gonadotropin levels during diestrus. Young adult females maintained on a vitamin D(3)-deficient diet after puberty had arrested follicular development and prolonged estrous cycles characterized by extended periods of diestrus. Ovaries of vitamin D(3)-deficient Cyp27b1 null mice responded to exogenous gonadotropins and deposited significantly more oocytes into the oviducts than mice maintained on a vitamin D(3)-replete diet. Estrous cycles were restored when vitamin D(3)-deficient Cyp27b1 null young adult females were transferred to a vitamin D(3)-replete diet. This study is the first to demonstrate that peripubertal vitamin D(3) sufficiency is important for an appropriately timed pubertal transition and maintenance of normal female reproductive physiology. These data suggest vitamin D(3) is a key regulator of neuroendocrine and ovarian physiology.

Effect of 25-hydroxyvitamin D3 and 1 α,25 dihydroxyvitamin D3 on differentiation and apoptosis of human osteosarcoma cell lines

Osteosarcoma (OS) is a malignant bone tumor predominantly affecting children and adolescents. OS has a 60% survival rate with current treatments; hence, there is a need to identify novel adjuncts to chemotherapeutic regimens. In this pilot study, we investigated the dose-response to 1α,25-dihdroxyvitamin D(3) (1,α 25(OH)(2) D(3)) and 25-hydroxyvitamin D(3) (25(OH)D(3)) by human OS cell lines, SaOS-2, and 143B. We hypothesized that 1,α 25(OH)(2) D(3) and 25(OH)D(3) would stimulate differentiation and induce apoptosis in OS cells in a dose-dependent manner. Human OS cell lines, SaOS-2, and 143B, were treated with 1,α 25(OH)(2)D(3) or 25(OH)D(3) or an ethanol control, respectively, at concentrations ranging from 1 to 1,000 nM. Ki67 (a marker of cellular proliferation) immunocytochemistry revealed no significant changes in the expression of Ki-67 or MIB-1 in 1α,25(OH)(2)D(3) or 25(OH)D(3) treated SaOS-2 or 143B cells. Both control and 1α,25(OH)(2) D(3) treated SaOS-2 and 143B cells expressed vitamin D receptor (VDR). Markers of osteoblastic differentiation in 143B cells and SaOS-2 cells were induced by both 25(OH)D(3) and 1α,25(OH)(2) D, and evident by increases in alkaline phosphatase (ALP) activity, osteocalcin (OCN) mRNA expression, and mineralization of extra-cellular matrix (ECM) by alizarin red staining. An increasing trend in apoptosis in response to 25(OH)D(3), in both SaOS-2 and 143B cells was detected by terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) staining. With 1α,25(OH)(2)D(3) treatment, apoptosis was evident at higher concentrations only. These preliminary findings suggest that OS cells express VDR and respond to 25(OH)D(3) and 1α,25(OH)(2)D(3) by undergoing differentiation and apoptosis.

Immunohistochemical identification of kidney nephron segments in the dog, rat, mouse, and cynomolgus monkey

Kidney is a major target organ in preclinical studies. In recent years, intense research has been undertaken to characterize novel renal toxicity biomarkers. In this context, we studied nephron segment specific antibodies against aquaporin-1 (AQP-1), α-glutathione-S-transferase (alpha-GST), Tamm-Horsfall protein (TH), calbindin-D(28K) (CalD), and aquaporin-2 (AQP-2), using an immunoperoxidase method on formalin-fixed paraffin-embedded kidney tissues of dogs, rats, mice, and Cynomolgus monkeys. AQP-1 was specific for proximal tubules and thin descending limbs of Henle's loops and AQP-2 for connecting and collecting ducts in dogs, rats, mice, and Cynomolgus monkeys. Alpha-GST stained the straight part of proximal tubules in dogs and proximal convoluted tubule and straight part of proximal tubules in rats. TH was specific for thick ascending limbs of Henle's loops in mice, rats, dogs, and Cynomolgus monkeys and stained additionally scattered cells in cortical connecting/collecting ducts of dogs. CalD was found in distal convoluted tubules and cortical connecting and collecting ducts of dogs, rats, and mice and in distal convoluted tubules, connecting ducts, and cortical and medullary collecting ducts of Cynomolgus monkey. This panel of antibodies may be a helpful tool to identify renal tubules by light microscopy in preclinical studies and to validate new biomarkers of renal toxicity.

The unfavorable effect of the A allele of the vitamin D receptor promoter polymorphism A-1012G has different mechanisms related to susceptibility and outcome of malignant melanoma

The A allele of the A-1012G (rs4516035) vitamin D receptor (VDR) promoter polymorphism is associated with increased susceptibility and worsened outcome in malignant melanoma (MM). The A allele contains a GATA-3 binding site. There is a second polymorphism in the same promoter region, G-1520C (rs7139166), and there is potential for another GATA binding site in the G allele. Here, we tested the hypothesis that the G(-1520)A(-1012) haplotype might be a greater risk factor for MM than A-1012 alone. The A allele of A-1012G was preferentially linked to G of G-1520C and was more frequent in MM patients (p = 0.011) but G of G-1520C was not (p = 0.756). The CA haplotype was a very significant risk factor for MM (p = 0.0001) while the CG haplotype was protective (p = 0.014, combined model p = 0.00002). There was no effect of GA haplotype (p = 0.931), suggesting that that the difference in frequencies of the A allele between patients and controls was accounted for by the differences in frequencies of the CA haplotype. The A allele of A-1012G was more frequent in patients with metastasis (p = 0.054) than MM patients without metastasis, as was the G allele of G-1520C (p = 0.028). The GA haplotype was more frequent in patients with metastasis (p = 0.015), while frequencies of CA were similar. We suggest that the different roles of the A allele of A-1012G in susceptibility and metastasis risk may be a function of the availability of transcription factors in the differing cellular backgrounds related to susceptibility and progression of MM.

Effect of vitamin D supplementation in type 2 diabetes patients with pulmonary tuberculosis

AIM

Diabetes and vitamin D deficiency are widely prevalent in India. Studies have proven correlation between low vitamin D levels and pulmonary tuberculosis (PTB) and low vitamin D levels and insulin resistance. We evaluated the effects of vitamin D supplementation on type 2 diabetes mellitus patients with pulmonary tuberculosis (PTB).

METHODS

Forty-five subjects (M:F=34:11) were screened. Inclusion criteria were age >15 years, newly diagnosed PTB cases with uncontrolled diabetes, serum vitamin D<20 ng/ml. The patients with vitamin D level<20 ng/ml were randomly assigned to 2 groups. Group 1 subjects received oral cholecalceferol (60,000 units/week) and calcium carbonate (1g/day) along with anti tubercular treatment (ATT), while group 2 subjects did not. Sputum was checked at interval of 2 weeks for 12 weeks. Primary end point was time to achieve sputum smear conversion.

RESULTS

Fifteen patients having vitamin D>20 ng/ml were excluded. Age of the patients was 42.9±13.2 years and serum vitamin D levels were 18.4±15.3 ng/ml. Sputum smear conversion was 6 weeks in group 1 versus 8 weeks in group 2 (p=0.067). Glycated hemoglobin levels reduced from 11.1±1.3 to 7.7±0.9 in group 1 versus 10.3±1.2 to 7.8±1.1 (p>0.1).

CONCLUSION

Vitamin D can serve as adjuvant treatment of tuberculosis in diabetics with vitamin D deficiency. Further studies are required to validate this observation and define a cut off for vitamin D level to prevent immunological alterations.

Prohibitin deficiency blocks proliferation and induces apoptosis in human hepatoma cells: molecular mechanisms and functional implications

Prohibitin is a multifunctional protein participating in a plethora of essential cellular functions, such as cell signaling, apoptosis, survival and proliferation. In the liver, deficient prohibitin activity participates in the progression of non-alcoholic steatohepatitis and obesity, according to mechanisms that still must be elucidated. In this study, we have used a combination of transcriptomics and proteomics technologies to investigate the response of human hepatoma PLC/PRF/5 cells to prohibitin silencing to define in detail the biological function of hepatic Phb1 and to elucidate potential prohibitin-dependent mechanisms participating in the maintenance of the transformed phenotype. Abrogation of prohibitin reduced proliferation and induced apoptosis in human hepatoma cells in a mechanism dependent on NF kappaB signaling. Moreover, down-regulation of ERp29 together with down-regulation of Erlin 2 suggests ER stress. In agreement, increased C/EBP homologous protein levels, poly-ADP ribose polymerase cleavage and activation of caspase 12 and downstream caspase 7 evidenced ER stress-induced apoptosis. Down-regulation of proteasome activator complex subunit 2 and stathmin as well as accumulation of ubiquitinated proteins suggest interplay between ER stress and proteasome malfunction. Taken together, our results provide evidences for prohibitin having a central role in the maintenance of the transformed and invasive phenotype of human hepatoma cells and may further support previous studies suggesting prohibitin as a potential clinical target.

Effects of calcitriol on calbindins gene expression and lipid peroxidation in human placenta

Pregnancy is associated with increased maternal calcitriol levels and placenta is an extrarenal source of this hormone. Calbindin-D9k and calbindin-D28k are vitamin D-dependent. Since calbindin-D28k has been considered as an antioxidant factor, the aim of the present work was to investigate the effects of calcitriol on calbindins gene expression and lipid peroxidation in cultured syncytiotrophoblast cells obtained from healthy human placentas. Gene expression of calbindins was evaluated using RT and real-time PCR techniques. Malondialdehyde (MDA) levels were used as lipid peroxidation marker. The results of the present study showed that cultured syncytiotrophoblast cells expressed the mRNA of calbindin-D9k and calbindin-D28k. In addition, calcitriol stimulated gene expression of both calbindins in a dose-dependent manner. Placental MDA levels were not significantly different at physiological concentrations of calcitriol (10(-11) M and 10(-9) M). However, the use of calcitriol at 10(-7) M resulted in significantly higher MDA levels (P<0.05). In conclusion, the results showed that cultured syncytiotrophoblast cells expressed calbindin-D9k and calbindin-D28k genes, which were stimulated by calcitriol. In addition, the results suggest that calcitriol may be considered as pro-oxidant when used at pharmacological doses.

Osteo-transcriptomics of human mesenchymal stem cells: accelerated gene expression and osteoblast differentiation induced by vitamin D reveals c-MYC as an enhancer of BMP2-induced osteogenesis

Bone marrow-derived human mesenchymal stem cells (hMSCs) have the in vitro capacity to differentiate into osteoblasts, chondrocytes or adipocytes, depending on the applied stimulus. In order to identify novel regulators of osteogenesis in hMSCs, osteo-transcriptomics was performed whereby differentiation induced by dexamethasone (DEX), DEX+ bone morphogenetic protein 2 (BMP2), and DEX+ Vitamin D(3) (1,25(OH)(2)D(3)) was studied over a course of 12 days. Microarray analysis revealed that 2095 genes were significantly regulated by DEX+ 1,25(OH)(2)D(3), of which 961 showed accelerated expression kinetics compared to treatment by DEX alone. The majority of these genes were accelerated 24-48 h after onset of osteogenic treatment. Gene ontology (GO) analysis of these 1,25(OH)(2)D(3)-accelerated genes indicated their involvement in biological processes related to cellular differentiation and cell cycle regulation. When compared to cells treated with DEX or DEX+BMP2, treatment with DEX+ 1,25(OH)(2)D(3) clearly accelerated osteoprogenitor commitment and osteoblast maturation, as measured by alkaline phosphatase (ALP) activity and calcification of the matrix. Cell cycle progression, as observed after initial growth arrest, was not significantly accelerated by 1,25(OH)(2)D(3) and was not required for onset and progression of osteogenesis. However, expression of c-Myc was accelerated by 1,25(OH)(2)D(3), and binding sites for c-MYC were enriched in promoters of genes accelerated by 1,25(OH)(2)D(3). Lentiviral overexpression of c-MYC strongly promoted DEX+ BMP2-induced osteoblast differentiation and matrix maturation. In conclusion, our studies show for the first time that 1,25(OH)(2)D(3) strongly accelerates expression of genes involved in differentiation of hMSCs and, moreover, identify c-MYC as a novel regulator of osteogenesis.

The adult boar testicular and epididymal transcriptomes

Background

Mammalians gamete production takes place in the testis but when they exit this organ, although spermatozoa have acquired a specialized and distinct morphology, they are immotile and infertile. It is only after their travel in the epididymis that sperm gain their motility and fertility. Epididymis is a crescent shaped organ adjacent to the testis that can be divided in three gross morphological regions, head (caput), body (corpus) and tail (cauda). It contains a long and unique convoluted tubule connected to the testis via the efferent ducts and finished by joining the vas deferens in its caudal part.

Results

In this study, the testis, the efferent ducts (vas efferens, VE), nine distinct successive epididymal segments and the deferent duct (vas deferens, VD) of four adult boars of known fertility were isolated and their mRNA extracted. The gene expression of each of these samples was analyzed using a pig generic 9 K nylon microarray (AGENAE program; GEO accession number: GPL3729) spotted with 8931 clones derived from normalized cDNA banks from different pig tissues including testis and epididymis. Differentially expressed transcripts were obtained with moderated t-tests and F-tests and two data clustering algorithms based either on partitioning around medoid (top down PAM) or hierarchical clustering (bottom up HCL) were combined for class discovery and gene expression analysis. Tissue clustering defined seven transcriptomic units: testis, vas efferens and five epididymal transcriptomic units. Meanwhile transcripts formed only four clusters related to the tissues. We have then used a specific statistical method to sort out genes specifically over-expressed (markers) in testis, VE or in each of the five transcriptomic units of the epididymis (including VD). The specific regional expression of some of these genes was further validated by PCR and Q-PCR. We also searched for specific pathways and functions using available gene ontology information.

Conclusion

This study described for the first time the complete transcriptomes of the testis, the epididymis, the vas efferens and the vas deferens on the same species. It described new genes or genes not yet reported over-expressed in these boar tissues, as well as new control mechanisms. It emphasizes and fulfilled the gap between studies done in rodents and human, and provides tools that will be useful for further studies on the biochemical processes responsible for the formation and maintain of the epididymal regionalization and the development of a fertile spermatozoa.

Expression and activity of vitamin D receptor in the human placenta and in choriocarcinoma BeWo and JEG-3 cell lines

Vitamin D receptor (VDR) regulates the expression of many genes involved in mineral metabolism, cellular proliferation, differentiation and drug biotransformation. We studied the expression and activity of VDR and its heterodimerization partner retinoid X receptor-alpha (RXRalpha) in choriocarcinoma trophoblast cell lines BeWo and JEG-3, in comparison with human isolated placental cytotrophoblasts and human full term placenta. We found that VDR and RXRalpha are localised in the human term placenta trophoblast and expressed in isolated cytotrophoblasts. However, we found low expression and no transcriptional activity of VDR in used choriocarcinoma cell lines. The inhibitor of DNA methylation, 5-deoxy-3'-azacytidine, and histone deacetylase inhibitor sodium butyrate partially restored the expression of VDR, suggesting an epigenetic suppression of the gene in choriocarcinoma cells. Differentiation of BeWo cells resulted in up-regulation of VDR mRNA. Finally, we observed a non-genomic effect of 1,25(OH)(2)D(3) in the activation of the extracellular signal-regulated kinase (ERK) signalling pathway in JEG-3 cells. In conclusion, our results suggest an epigenetic repression of VDR gene expression and activity in choriocarcinoma cell lines, and a non-genomic effect of 1,25(OH)(2)D(3) in JEG-3 cells.

Dietary calcium and 1,25-dihydroxyvitamin D3 regulate transcription of calcium transporter genes in calbindin-D9k knockout mice

The effect(s) of oral calcium and vitamin D(3) were examined on the expression of duodenal and renal active calcium transport genes, i.e., calbindin-D9k (CaBP-9k) and calbindin-D28k (CaBP-28k), transient receptor potential cation channels (TRPV5 and TRPV6), Na(+)/Ca(2+) exchanger 1 (NCX1) and plasma membrane calcium ATPase 1b (PMCA1b), in CaBP-9k KO mice. Wild-type (WT) and KO mice were provided with calcium and vitamin D(3)-deficient diets for 10 weeks. The deficient diet significantly decreased body weights compared with the normal diet groups. The serum calcium concentration of the WT mice was decreased by the deficient diet but was unchanged in the KO mice. The deficient diet significantly increased duodenal transcription of CaBP-9k and TRPV6 in the WT mice, but no alteration was observed in the KO mice. In the kidney, the deficient diet significantly increased renal transcripts of CaBP-9k, TRPV6, PMCA1b, CaBP-28k and TRPV5 in the WT mice but did not alter calcium-relating genes in the KO mice. Two potential mediators of calcium-processing genes, vitamin D receptor (VDR) and parathyroid hormone receptor (PTHR), have been suggested to be useful for elucidating these differential regulations in the calcium-related genes of the KO mice. Expression of VDR was not significantly affected by diet or the KO mutation. Renal PTHR mRNA levels were reduced by the diet, and reduced expression was also seen in the KO mice given the normal diet. Taken together, these results suggest that the active calcium transporting genes in KO mice may have resistance to the deficiency diet of calcium and vitamin D(3).

Calcium transport in strongly calcifying laying birds: mechanisms and regulation

Birds that lay long clutches (series of eggs laid sequentially before a "pause day"), among them the high-producing, strongly-calcifying Gallus gallus domesticus (domestic hen) and Coturnix coturnix japonica (Japanese quail), transfer about 10% of their total body calcium daily. They appear, therefore, to be the most efficient calcium-transporters among vertebrates. Such intensive transport imposes severe demands on ionic calcium (Ca2+) homeostasis, and activates at least two extremely effective mechanisms for Ca2+ transfer from food and bone to the eggshell. This review focuses on the development, action and regulation of the mechanisms associated with paracellular and transcellular Ca2+ transport in the intestine and the eggshell gland (ESG); it also considers some of the proteins (calbindin, Ca2+ATPase, Na+/Ca2+ exchange, epithelial calcium channels (TRPVs), osteopontin and carbonic anhydrase (CA) associated with this phenomenon. Calbindins are discussed in some detail, as they appear to be a major component of the transcellular transport system, and as only they have been studied extensively in birds. The review aims to gather old and new knowledge, which could form a conceptual basis, albeit not a completely accepted one, for our understanding of the mechanisms associated with this phenomenon. In the intestine, the transcellular pathway appears to compensate for low Ca2+ intake, but in birds fed adequate calcium the major drive for calcium absorption remains the electrochemical potential difference (ECPD) that facilitates paracellular transport. However, the mechanisms involved in Ca2+ transport into the ESG lumen are not yet established. In the ESG, the presence of Ca2+-ATPase and calbindin--two components of the transcellular transport pathway--and the apparently uphill transport of Ca2+ support the idea that Ca2+ is transported via the transcellular pathway. However, the positive (plasma with respect to mucosa) electrical potential difference (EPD) in the ESG, among other findings, indicates that there may be major alternative or complementary paracellular passive transport pathways. The available evidence hints that the flow from the gut to the ESG, which occurs during a relatively short period (11 to 14 h out the 24- to 25.5-h egg cycle), is primarily driven by carbonic anhydrase (CA) activity in the ESG, which results in high HCO3(-) content that, in turn, "sucks out" Ca2+ from the intestinal lumen via the blood and ESG cells, and deposits it in the shell crystals. The increased CA activity appears to be dependent on energy input, whereas it seems most likely that the Ca2+ movement is secondary, that it utilizes passive paracellular routes that fluctuate in accordance with the appearance of the energy-dependent CA activity, and that the level of Ca2+ movement mimics that of the CA activity. The on-off signals for the overall phenomenon have not yet been identified. They appear to be associated with the circadian cycle of gonadal hormones, coupled with the egg cycle: it is most likely that progesterone acts as the "off" signal, and that the "on" signal is provided by the combined effect of an as-yet undefined endocrine factor associated with ovulation and with the mechanical strain that results from "egg white" formation and "plumping". This strain may initially trigger the formation of the mammillae and the seeding of shell calcium crystals in the isthmus, and thereafter initiate the formation of the shell in the ESG.

Endocrine regulation of calcium transport in epithelia

1. Calcium (re)absorption occurs in epithelia, including the intestine, kidney, mammary glands, placenta and gills (in the case of fish). 2. Calcium is transported across epithelia by two transport mechanisms, paracellular and transcellular, and the movement is regulated by a complex array of transport processes that are mediated by hormonal, developmental and physiological factors involving the gastrointestinal tract, bone, kidney and the parathyroids. 3. Clear understanding of the calcium transport pathways and their endocrine regulation is critical for minimizing various metabolic and health disorders at different physiological stages. Here, we first briefly review the calcium transport mechanisms before discussing in detail the endocrine factors that regulate calcium transport in the epithelia.

Vitamin D receptor amounts across different segments of the gastrointestinal tract in Brown Swiss and Holstein Frisean cows of different age

During different stages of lactation, different requirements of calcium have to be met depending on the milk amount. Vitamin D receptors (VDR) regulate calcium homeostasis by increasing the entry of Ca into blood from bone stores and dietary sources. The purpose of this study was to investigate if age and breed of cows influence VDR amounts across different segments of the gastrointestinal tract. Thirty-six cows were used (18 Brown Swiss, 18 Holstein Friesan, both > 5.5 years or < 4.5 years). Tissue specimens of the intestines were collected from the cows. Formaldehyde-fixed and microwave-treated paraffin sections were used for VDR immunohistochemistry employing a biotinylated monoclonal rat antibody and streptavidin peroxidase technique. The results showed that nuclei and cytoplasm of enterocytes stained positively for VDRs. Strongest immunoreactions were observed in intermediate and basal glandular cells. No significant differences were observed between the different groups. Vitamin D receptors immunoreactivities were prominent in duodenal mucosa, lower in jejunum and in colon, decreased further in ileum and were lowest in caecum. Decreases in number of positively marked cells and staining intensities resulted in reduced immunoreactions. The results of this study indicate that VDR are highly expressed at the site of maximal intestinal calcium absorption. No significant influence of age and breed was observed. The animals used were not in a negative Ca balance. The cows were all in the stage of late or mid lactation. During these periods, the Ca requirements are low and the diets are high in Ca concentration; and the animals are adapted to these circumstances. Passive absorption in adult animals seems to dominate when Ca intake is adequate or high. The active absorption may play a considerably more significant role during the peripartal period, when Ca homeostatic mechanisms are challenged because of tremendous Ca demand at the initiation of lactation.

Effects of weak, low-frequency pulsed electromagnetic fields (BEMER type) on gene expression of human mesenchymal stem cells and chondrocytes: an in vitro study

In vitro effects of electromagnetic fields appear to be related to the type of electromagnetic field applied. Previously, we showed that human osteoblasts display effects of BEMER type electromagnetic field (BTEMF) on gene regulation. Here, we analyze effects of BTEMF on gene expression in human mesenchymal stem cells and chondrocytes. Primary mesenchymal stem cells from bone marrow and the chondrocyte cell line C28I2 were stimulated 5 times at 12-h intervals for 8 min each with BTEMF. RNA from treated and control cells was analyzed for gene expression using the affymetrix chip HG-U133A. A limited number of regulated gene products from both cell types mainly affect cell metabolism and cell matrix structure. There was no increased expression of cancer-related genes. RT-PCR analysis of selected transcripts partly confirmed array data. Results indicate that BTEMF in human mesenchymal stem cells and chondrocytes provide the first indications to understanding therapeutic effects achieved with BTEMF stimulation.