Paricalcitol accelerates BACE1 lysosomal degradation and inhibits calpain-1 dependent neuronal loss in APP/PS1 transgenic mice.

BACKGROUND: Recent studies have revealed that vitamin D deficiency may increase the risk of Alzheimer's disease, and vitamin D supplementation may be effective strategy to ameliorate the neurodegenerative process in Alzheimer's disease patients. Paricalcitol (PAL), a low-calcemic vitamin D receptor agonist, is clinically used to treat secondary hyperparathyroidism. However, the potential application of PAL for treating neurodegenerative disorders remains unexplored. METHODS: The APP/PS1 mice were intraperitoneally injected with PAL or vehicle every other day for 15 weeks. The ß-amyloid (Aß) production was confirmed using immunostaining and enzyme linked immunosorbent assay. The underlying mechanism was verified by western blot and immunostaining in vivo and in vitro. FINDINGS: Long-term PAL treatment clearly reduced ß-amyloid (Aß) generation and neuronal loss in APP/PS1 transgenic mouse brains. PAL stimulated the expression of low-density lipoprotein receptor-related protein 1 (LRP1) possibly through inhibiting sterol regulatory element binding protein-2 (SREBP2); PAL also promoted LRP1-mediated ß-site APP cleavage enzyme 1 (BACE1) transport to late endosomes, thus increasing the lysosomal degradation of BACE1. Furthermore, PAL diminished 8-hydroxyguanosine (8-OHdG) generation in neuronal mitochondria via enhancing base excision repair (BER), resulting in the attenuation of calpain-1-mediated neuronal loss. INTERPRETATION: The present data demonstrate that PAL can reduce Aß generation through accelerating BACE1 lysosomal degradation and can inhibit neuronal loss through suppressing mitochondrial 8-OHdG generation. Hence, PAL might be a promising agent for treating Alzheimer's disease. FUND: This study was financially supported by the Natural Science Foundation of China (U1608282).

Losartan and Vitamin D Inhibit Colonic Tumor Development in a Conditional Apc-Deleted Mouse Model of Sporadic Colon Cancer.

Colorectal cancer is a leading cause of cancer deaths. The renin-angiotensin system (RAS) is upregulated in colorectal cancer, and epidemiologic studies suggest RAS inhibitors reduce cancer risk. Because vitamin D (VD) receptor negatively regulates renin, we examined anticancer efficacy of VD and losartan (L), an angiotensin receptor blocker. Control Apc+/LoxP mice and tumor-forming Apc+/LoxP Cdx2P-Cre mice were randomized to unsupplemented Western diet (UN), or diets supplemented with VD, L, or VD+L, the latter to assess additive or synergistic effects. At 6 months, mice were killed. Plasma Ca2+, 25(OH)D3, 1α, 25(OH)2D3, renin, and angiotensin II (Ang II) were quantified. Colonic transcripts were assessed by qPCR and proteins by immunostaining and blotting. Cancer incidence and tumor burden were significantly lower in Cre+ VD and Cre+ L, but not in the Cre+ VD+L group. In Apc+/LoxP mice, VD increased plasma 1,25(OH)2D3 and colonic VDR. In Apc+/LoxP-Cdx2P-Cre mice, plasma renin and Ang II, and colonic tumor AT1, AT2, and Cyp27B1 were increased and VDR downregulated. L increased, whereas VD decreased plasma renin and Ang II in Cre+ mice. VD or L inhibited tumor development, while exerting differential effects on plasma VD metabolites and RAS components. We speculate that AT1 is critical for tumor development, whereas RAS suppression plays a key role in VD chemoprevention. When combined with L, VD no longer increases active VD and colonic VDR in Cre- mice nor suppresses renin and Ang II in Cre+ mice, likely contributing to lack of chemopreventive efficacy of the combination.

[Effects of biochar and sheep manure on rhizospheric soil microbial community in continuous ratooning tea orchards]. / æ–½ç”¨ç”Ÿç‰©è´¨ç‚­å’Œç¾Šç²ªå¯¹å®¿æ ¹è¿žä½œèŒ¶å›­æ ¹é™ åœŸå£¤å¾®ç”Ÿç‰©çš„å½±å“.

Long-term continuous ratooning of tea could lead to serious soil acidification, nutritional imbalance, and the deterioration of the rhizosphere micro-ecological environment. Understanding the effects of biochar and sheep manure on the growth of tea plants and the rhizosphere microbial community structure and function would provide theoretical basis to improve the soil micro-ecological environment of continuous ratooning tea orchards. Biolog technology combined with phospholipid fatty acid (PLFA) approaches were employed to quantify the effects of biochar (40 t·hm-2) and sheep manure on the growth of 20 years continuous ratooning tea plants, soil chemical properties, and the soil microbial community structure and function. The results showed that after one year treatment, biochar and sheep manure both improved soil pH and nutrition, and significantly enhanced tea production. Compared with the routine fertilizer application (CK), the biochar and sheep manure treatments significantly increased the carbon metabolic activity (AWCD) and microorganism diversity in the rhizosphere soils, and increased the relative utilization of the carbon sources such as amines, carbohydrates, and polymers. The total PLFA concentrations in the biochar and sheep manure treatments were significantly increased by 20.9% and 47.5% than that in the routine fertilizers application. In addition, sheep manure treatment significantly decreased the saturated/monosaturated fatty acids In conclusion, biochar and sheep manure could alleviate soil acidification, enhance soil nutrition and the growth of tea plants. Both management strategies could increase the soil microbial activity and biomass, enhance the diversity, and improve the microbial community structure, which could be taken as effective measures to regulate the rhizosphere micro-environment of tea plants.

Evaluation of responses to vitamin D3 (cholecalciferol) in patients on dialysis: a systematic review and meta-analysis.

Vitamin D plays a key role in mineral metabolism and its deficiency is often noted in patients on dialysis for end-stage renal disease (ESRD). We evaluated the efficacy and responses to vitamin D3 (cholecalciferol) in patients undergoing dialysis for ESRD. Randomized controlled trials or prospective studies comparing vitamin D3 supplementation to placebo in patients with ESRD on dialysis were searched from medical databases using the terms, 'Calcitriol/Cholecalciferol, vitamin D, chronic kidney disease, hemodialysis, serum calcium, parathyroid hormones (PTH), phosphorus, 25(OH)D, and 1,25(OH)2D'. The outcomes analyzed were serum calcium, PTH, phosphorus, 25(OH)D, and 1,25(OH) 2D levels. Of the 259 records identified, 9 studies with a total of 368 patients were chosen for the current meta-analysis. The number of patients, age, and gender distribution among the groups were comparable. Results reveal a greater increase in both 25(OH)D (Pooled difference in means=0.434, 95% CI 0.174 to 0.694, p=0.001) and 1,25(OH) 2D (Pooled difference in means=0.978, 95% CI 0.615 to 1.34, p<0.001) in the treatment arm, as compared to the placebo. There was no difference in the serum calcium or PTH among the two groups. However, patients in the treatment arm had a significant increase in phosphorus levels (Pooled difference in means=0.434, 95% CI 0.174 to 0.694, p=0.001). Vitamin D supplementation facilitated the maintenance of increased levels of 25(OH) D and 1,25(OH) 2D in patients undergoing dialysis for ESRD. This increase in vitamin D was not associated with hypercalcemia or significant changes in PTH levels.

Blockade of Androgen Markers Using a Novel Betasitosterol, Thioctic Acid and Carnitine-containing Compound in Prostate and Hair Follicle Cell-based Assays.

Androgenetic alopecia (AGA) affects approximately 70% of men and 40% of women in an age-dependent manner and is partially mediated by androgen hormones. Benign prostatic hyperplasia (BPH) similarly affects 50% of the male population, rising by 10% each decade. Finasteride inhibits 5-alpha reductase (5AR) and is used to treat both disorders, despite offering limited clinical benefits accompanied by significant adverse side effects. Building on our previous work demonstrating the efficacy of naturally derived 5AR inhibitors (such as stigmasterol and beta sitosterol), we hypothesize that targeting 5AR as well as inflammatory pathways may yield improved efficacy in AGA and BPH. Here we address these dual pathomechanisms by examining the potency of a novel composition using in vitro assays of representative cell lines for AGA (hair follicle dermal papilla cells) and BPH (LNCaP prostate cells), respectively. Exposure of cells to the novel test composition down-regulated mRNA expression profiles characteristic of both disease processes, which outperformed finasteride. Changes in mRNA expression were corroborated at the protein level as assessed by western blotting. These studies provide proof of concept that novel, naturally derived compositions simultaneously targeting 5AR and inflammatory mediators may represent a rational approach to treating AGA and BPH. Copyright © 2016 John Wiley & Sons, Ltd.

Role of vitamin D in cytotoxic T lymphocyte immunity to pathogens and cancer.

The discovery of vitamin D receptor (VDR) expression in immune cells has opened up a new area of research into immunoregulation by vitamin D, a niche that is distinct from its classical role in skeletal health. Today, about three decades since this discovery, numerous cellular and molecular targets of vitamin D in the immune system have been delineated. Moreover, strong clinical associations between vitamin D status and the incidence/severity of many immune-regulated disorders (e.g. infectious diseases, cancers and autoimmunity) have prompted the idea of using vitamin D supplementation to manipulate disease outcome. While much is known about the effects of vitamin D on innate immune responses and helper T (T(H)) cell immunity, there has been relatively limited progress on the frontier of cytotoxic T lymphocyte (CTL) immunity--an arm of host cellular adaptive immunity that is crucial for the control of such intracellular pathogens as human immunodeficiency virus (HIV), tuberculosis (TB), malaria, and hepatitis C virus (HCV). In this review, we discuss the strong historical and clinical link between vitamin D and infectious diseases that involves cytotoxic T lymphocyte (CTL) immunity, present our current understanding as well as critical knowledge gaps in the realm of vitamin D regulation of host CTL responses, and highlight potential regulatory connections between vitamin D and effector and memory CD8 T cell differentiation events during infections.

Nutritional vitamin D supplementation in dialysis: a randomized trial.

BACKGROUND AND OBJECTIVES: Vitamin D (25-hydroxyvitamin D; 25[OH]D) deficiency is common in patients initiating long-term hemodialysis, but the safety and efficacy of nutritional vitamin D supplementation in this population remain uncertain. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: This randomized, placebo-controlled, parallel-group multicenter trial compared two doses of ergocalciferol with placebo between October 2009 and March 2013. Hemodialysis patients (n=105) with 25(OH)D levels ≤32 ng/ml from 32 centers in the Northeast United States were randomly assigned to oral ergocalciferol, 50,000 IU weekly (n=36) or monthly (n=33), or placebo (n=36) for a 12-week treatment period. The primary endpoint was the achievement of vitamin D sufficiency (25[OH]D >32 ng/ml) at the end of the 12-week treatment period. Survival was assessed through 1 year. RESULTS: Baseline characteristics were similar across all arms, with overall mean±SD 25(OH)D levels of 21.9±6.9 ng/ml. At 12 weeks, vitamin D sufficiency (25[OH]D >32 ng/ml) was achieved in 91% (weekly), 66% (monthly), and 35% (placebo) (P<0.001). Mean 25(OH)D was significantly higher in both the weekly (49.8±2.3 ng/ml; P<0.001) and monthly (38.3±2.4 ng/ml; P=0.001) arms compared with placebo (27.4±2.3 ng/ml). Calcium, phosphate, parathyroid hormone levels, and active vitamin D treatment did not differ between groups. All-cause and cause-specific hospitalizations and adverse events were similar between groups during the intervention period. Lower all-cause mortality among ergocalciferol-treated participants was not statistically significant (hazard ratio, 0.28; 95% confidence interval, 0.07 to 1.19). CONCLUSIONS: Oral ergocalciferol can increase 25(OH)D levels in incident hemodialysis patients without significant alterations in blood calcium, phosphate, or parathyroid hormone during a 12-week period.

The renin-angiotensin system mediates EGF receptor-vitamin d receptor cross-talk in colitis-associated colon cancer.

PURPOSE: We previously showed that EGF receptor (EGFR) promotes tumorigenesis in the azoxymethane/dextran sulfate sodium (AOM/DSS) model, whereas vitamin D suppresses tumorigenesis. EGFR-vitamin D receptor (VDR) interactions, however, are incompletely understood. Vitamin D inhibits the renin-angiotensin system (RAS), whereas RAS can activate EGFR. We aimed to elucidate EGFR-VDR cross-talk in colorectal carcinogenesis. EXPERIMENTAL DESIGN: To examine VDR-RAS interactions, we treated Vdr(+/+) and Vdr(-/-) mice with AOM/DSS. Effects of VDR on RAS and EGFR were examined by Western blotting, immunostaining, and real-time PCR. We also examined the effect of vitamin D3 on colonic RAS in Vdr(+/+) mice. EGFR regulation of VDR was examined in hypomorphic Egfr(Waved2) (Wa2) and Egfr(wild-type) mice. Angiotensin II (Ang II)-induced EGFR activation was studied in cell culture. RESULTS: Vdr deletion significantly increased tumorigenesis, activated EGFR and ß-catenin signaling, and increased colonic RAS components, including renin and angiotensin II. Dietary VD3 supplementation suppressed colonic renin. Renin was increased in human colon cancers. In studies in vitro, Ang II activated EGFR and stimulated colon cancer cell proliferation by an EGFR-mediated mechanism. Ang II also activated macrophages and colonic fibroblasts. Compared with tumors from Egfr(Waved2) mice, tumors from Egfr(wild-type) mice showed upregulated Snail1, a suppressor of VDR, and downregulated VDR. CONCLUSIONS: VDR suppresses the colonic RAS cascade, limits EGFR signals, and inhibits colitis-associated tumorigenesis, whereas EGFR increases Snail1 and downregulates VDR in colonic tumors. Taken together, these results uncover a RAS-dependent mechanism mediating EGFR and VDR cross-talk in colon cancer.

Severe vitamin D-deficiency and increased bone turnover in patients with hepatitis B from northeastern China.

INTRODUCTION: Vitamin D plays a key role in maintaining calcium homeostasis and skeletal health. The liver is critically involved in vitamin D metabolism, as 25-hydroxyvitamin D3 (25(OH)D3) is synthesized in the liver. Therefore liver dysfunction may lead to vitamin D deficiency and bone problems. The aim of this study was to examine vitamin D status and bone turnover markers in hepatitis B patients from northeastern China. METHODS: We recruited 39 patients with hepatitis B (23 noncirrhotic and 16 cirrhotic) and 48 healthy controls in Shenyang, a metropolitan city in northeastern China, and measured serum 25(OH)D3 levels and serum and urinary bone turnover markers in these subjects. RESULTS: Serum 25(OH)D3 levels in the patients with or without cirrhosis were markedly lower compared to the nonhepatitis controls (19.2 ± 1.2 and 18.5 ± 1.3 vs. 31.6 ± 1.3 nmol/L control), whereas serum and urinary bone turnover markers (alkaline phosphatase, C-terminal telopeptide of type I collagen, and pyridinoline) were significantly higher in these patients than in the controls. Moreover, serum levels of osteoprotegerin, a bone mass-regulating protein, were substantially reduced in the patients, with the lowest seen in patients with cirrhosis (2.7 ± 1.1 and 1.4 ± 0.4 vs. 3.4 ± 0.7 pg/mL control). Serum 25(OH)D3 levels below 30 nmol/L were positively correlated with serum osteoprotegerin levels in this cohort. CONCLUSIONS: Severe vitamin D deficiency is very common in hepatitis B patients in northeastern China, which negatively impacts their bone health. These data strongly suggest a need to treat these patients with vitamin D supplementation to protect their bone health.

Vitamin D in chronic kidney disease.

Vitamin D deficiency is highly prevalent in patients with chronic kidney disease (CKD). The low vitamin D status is, to a large extent, caused by dysregulation of vitamin D metabolism as a result of renal insufficiency. Recent studies indicate that vitamin D-deficiency may promote or accelerate the progression of CKD, whereas treatment with low calcemic vitamin D analogs can reduce proteinuria and ameliorate renal damage in animal models of kidney disease and in patients with CKD. The renoprotective activity of vitamin D regulates multiple signaling pathways known to play important roles in renal injury. These findings underscore the importance of correcting vitamin D deficiency with vitamin D supplementation or with activated vitamin D analogs in the management of CKD.

Hyperdopaminergic modulation of inhibitory transmission is dependent on GSK-3ß signaling-mediated trafficking of GABAA receptors.

Cortical dopamine (DA) modulation of the gamma-amino butyric acid (GABA) system is closely associated with cognitive function and psychiatric disorders. We recently reported that the glycogen synthase kinase 3ß (GSK-3ß) pathway is required for hyperdopamine/D2 receptor-mediated inhibition of NMDA receptors in the prefrontal cortex. Here we explore whether or not GSK-3ß is also involved in dopaminergic modulation of GABAA receptor-mediated inhibitory transmission. We confirmed that DA induces a dose-dependent, bidirectional regulatory effect on inhibitory postsynaptic currents (IPSCs) in prefrontal neurons. The modulatory effects of DA were differentially affected by co-application of GSK-3ß inhibitors and different doses of DA. GSK-3ß inhibitors completely blocked high-dose (20 µM) DA-induced depressive effects on IPSCs but exhibited limited effects on the facilitating regulation of IPSC in low-dose DA (200 nM). We also confirmed that surface expressions of GABAA receptor ß2/3 subunits were significantly decreased by DA applied in cultured prefrontal neurons and in vivo administration of DA reuptake inhibitor. These effects were blocked by prior administration of GSK-3ß inhibitors. We explored DA-mediated regulation of GABAA receptor trafficking and exhibited the participation of brefeldin A-inhibited GDP/GTP exchange factor 2 (BIG2) or dynamin-dependent trafficking of GABAA receptors. Together, these data suggest that DA may act through different signaling pathways to affect synaptic inhibition, depending on the concentration. The GSK-3ß signaling pathway is involved in DA-induced decrease in BIG2-dependent insertion and an increase in the dynamin-dependent internalization of GABAA receptors, which results in suppression of inhibitory synaptic transmission.

Ursodeoxycholic acid suppresses Cox-2 expression in colon cancer: roles of Ras, p38, and CCAAT/enhancer-binding protein.

In the azoxymethane (AOM) model of experimental rodent colon cancer, cholic acid and its colonic metabolite deoxycholic acid (DCA) strongly promote tumorigenesis. In contrast, we showed that ursodeoxycholic acid (UDCA), a low abundance bile acid, inhibited AOM tumorigenesis. Dietary UDCA also blocked the development of tumors with activated Ras and suppressed cyclooxygenase-2 (Cox-2) upregulation in AOM tumors. In this study, we compared the effect of dietary supplementation with tumor-promoting cholic acid to chemopreventive UDCA on Cox-2 expression in AOM tumors. Cholic acid enhanced Cox-2 upregulation in AOM tumors, whereas UDCA inhibited this increase and concomitantly decreased CCAAT/enhancer binding protein beta (C/EBPbeta), a transcriptional regulator of Cox-2. In HCA-7 colon cancer cells, DCA activated Ras and increased C/EBPbeta and Cox-2 by a mechanism requiring the mitogen-activated protein kinase p38. UDCA inhibited DCA-induced p38 activation and decreased C/EBPbeta and Cox-2 upregulation. Using transient transfections, UDCA inhibited Cox-2 promoter and C/EBP reporter activation by DCA. Transfection with dominant-negative (17)N-Ras abolished DCA-induced p38 activation and C/EBPbeta and Cox-2 upregulation. Taken together, these studies have identified a transcriptional pathway regulating Cox-2 expression involving Ras, p38, and C/EBPbeta that is inhibited by UDCA. These signal transducers are novel targets of UDCA's chemopreventive actions.

Beta-eudesmol suppresses tumour growth through inhibition of tumour neovascularisation and tumour cell proliferation.

In the present study, we investigated the potential anti-angiogenic mechanism and anti-tumour activity of beta-eudesmol using in vitro and in vivo experimental models. Proliferation of human umbilical vein endothelial cells (HUVEC) stimulated with vascular endothelial growth factor (VEGF, 30 ng/ml) and basic fibroblast growth factor (bFGF, 30 ng/ml) was significantly inhibited by beta-eudesmol (50-100 microM). Beta-eudesmol (100 microM) also blocked the phosphorylation of cAMP response element binding protein (CREB) induced by VEGF (30 ng/ml) in HUVEC. Beta-eudesmol (10-100 microM) inhibited proliferation of HeLa, SGC-7901, and BEL-7402 tumour cells in a time- and dose-dependent manner. Moreover, beta-eudesmol treatment (2.5-5 mg/kg) significantly inhibited growth of H(22) and S(180) mouse tumour in vivo. These results indicated that beta-eudesmol inhibited angiogenesis by suppressing CREB activation in growth factor signalling pathway. This is the first study to demonstrate that beta-eudesmol is an inhibitor of tumour growth.

Critical role of calbindin-D28k in calcium homeostasis revealed by mice lacking both vitamin D receptor and calbindin-D28k.

Calbindin (CaBP)-D28k and CaBP-D9k are cytosolic vitamin D-dependent calcium-binding proteins long thought to play an important role in transepithelial calcium transport. However, recent genetic studies suggest that CaBP-D28k is not essential for calcium metabolism. Genetic ablation of this gene in mice leads to no calcemic abnormalities. Genetic inactivation of the vitamin D receptor (VDR) gene leads to hypocalcemia, secondary hyperparathyroidism, rickets, and osteomalacia, accompanied by 90% reduction in renal CaBP-D9k expression but little change in CaBP-D28k. To address whether the role of CaBP-D28k in calcium homeostasis is compensated by CaBP-D9k, we generated VDR/CaBP-D28k double knockout (KO) mice, which expressed no CaBP-D28k and only 10% of CaBP-D9k in the kidney. On a regular diet, the double KO mice were more growth-retarded and 42% smaller in body weight than VDRKO mice and died prematurely at 2.5-3 months of age. Compared with VDRKO mice, the double KO mice had higher urinary calcium excretion and developed more severe secondary hyperparathyroidism and rachitic skeletal phenotype, which were manifested by larger parathyroid glands, higher serum parathyroid hormone levels, much lower bone mineral density, and more distorted growth plate with more osteoid formation in the trabecular region. On high calcium, high lactose diet, blood-ionized calcium levels were normalized in both VDRKO and the double KO mice; however, in contrast to VDRKO mice, the skeletal abnormalities were not completely corrected in the double KO mice. These results directly demonstrate that CaBP-D28k plays a critical role in maintaining calcium homeostasis and skeletal mineralization and suggest that its calcemic role can be mostly compensated by CaBP-D9k.

Critical role of vitamin D in sulfate homeostasis: regulation of the sodium-sulfate cotransporter by 1,25-dihydroxyvitamin D3.

As the fourth most abundant anion in the body, sulfate plays an essential role in numerous physiological processes. One key protein involved in transcellular transport of sulfate is the sodium-sulfate cotransporter NaSi-1, and previous studies suggest that vitamin D modulates sulfate homeostasis by regulating NaSi-1 expression. In the present study, we found that, in mice lacking the vitamin D receptor (VDR), NaSi-1 expression in the kidney was reduced by 72% but intestinal NaSi-1 levels remained unchanged. In connection with these findings, urinary sulfate excretion was increased by 42% whereas serum sulfate concentration was reduced by 50% in VDR knockout mice. Moreover, levels of hepatic glutathione and skeletal sulfated proteoglycans were also reduced by 18 and 45%, respectively, in the mutant mice. Similar results were observed in VDR knockout mice after their blood ionized calcium levels and rachitic bone phenotype were normalized by dietary means, indicating that vitamin D regulation of NaSi-1 expression and sulfate metabolism is independent of its role in calcium metabolism. Treatment of wild-type mice with 1,25-dihydroxyvitamin D3 or vitamin D analog markedly stimulated renal NaSi-1 mRNA expression. These data provide strong in vivo evidence that vitamin D plays a critical role in sulfate homeostasis. However, the observation that serum sulfate and skeletal proteoglycan levels in normocalcemic VDR knockout mice remained low in the absence of rickets and osteomalacia suggests that the contribution of sulfate deficiency to development of rickets and osteomalacia is minimal.

Altered gene expression profile in the kidney of vitamin D receptor knockout mice.

The kidney is a primary target organ of the vitamin D endocrine system, and both vitamin D-deficiency and vitamin D receptor (VDR) ablation lead to impaired renal functions. As an initial step to understand the molecular basis underlying the renal dysfunctions resulted from VDR inactivation, we used DNA microarray technology to search for changes in the gene expression profile in the kidney of VDR knockout mice. Three independent DNA microarray experiments were performed using Affymetrix GeneChips, which included two replicate comparisons between VDR null and wild-type littermates, and a third comparison between 1,25-dihydroxyvitamin D(3)-treated and vehicle-treated wild-type mice. Based on the assumption that VDR inactivation and vitamin D stimulation cause opposite changes in the expression of vitamin D target genes, we identified 95 genes that displayed the same changes in the two VDR-null/wild-type comparisons but an opposite change in the third assay, of which 28 genes were up-regulated and 67 were down-regulated in VDR null mice. These genes can be divided into several functional categories involved in vitamin D and steroid metabolism, calcium metabolism and signaling, volume and electrolyte homeostasis, signal transduction, transcriptional regulation, cell adhesion, metabolism, immune response, and other functions. These data provide a basis for further investigations into the molecular bases underlying the physiological abnormalities associated with VDR- and vitamin D-deficiency.

[MnSOD gene regulated by aminopeptidase N promoter specifically protects bone marrow from radiation].

BACKGROUND & OBJECTIVE: It is an effective way to induce radio-tolerant gene into hematopoietic cells in bone marrow for overcoming the suppression of radiotherapy on hematopoietic system. However, this also increases the radiation tolerance of tumor cells. This study was designed to investigate a method to specifically protect bone marrow cell from being damaged by radiation, along without increasing resistance of tumor cell to radiation. METHODS: The retrovirus vector of manganese superoxide dismutase (MnSOD) gene regulated by aminopeptidase N (APN) bone marrow-specific gene promoter was constructed and induced into myeloblastic KG1a and cancer cell BEL7402. MnSOD mRNA level was analyzed by PT-PCR; MnSOD activity in the cells was determined; the sensitivity of bone marrow cell and hepatic carcinoma cell to x-ray was detected by cell survival test; the cell apoptosis was analyzed with flow cytometry and fractural DNA electrophoresis. RESULTS: The MnSOD mRNA level and enzyme activity in KG1a cells transferred with the gene was obviously increased. Expression of MnSOD mRNA drove by APN myelo-specific promoter effectively inhibited apoptosis of KG1a cells induced by radiation and endowed KG1a cell line with the enhancement of tolerance to radiation, which increased by 3.7 folds compared to parental cells at the dose of 10 Gy. In contrast, the level of MnSOD mRNA, the enyme activity of MnSOD and the radiosensitivity had no significant change in BEL 7402 cells transduced with MnSOD gene. CONCLUSION: APN bone marrow-specific promoter could control MnSOD gene expression highly in myeloid cell and lower in cancer cell. In the process of killing of cancer cell by x-ray, MnSOD gene regulated by APN bone marrow-specific promoter could specifically protect myeloid cell. This study provides a new clue to solve the bone marrow suppression in high dose radiotherapy.