Downregulation Of Vitamin D Receptor Research Articles

Vitamin D receptor induces oxidative stress to promote esophageal squamous cell carcinoma proliferation via the p53 signaling pathway

BackgroundEsophageal squamous cell carcinoma (ESCC) is a common pathological esophageal cancer with poor prognosis. Vitamin D deficiency reportedly occurs in ESCC patients, and this is related to single nucleotide polymorphism of vitamin D receptor (VDR). ObjectiveWe investigated the effect of VDR on ESCC proliferation, invasion, and metastasis and its potential mechanism. MethodsESCC and normal tissues were collected from 20 ESCC patients. The ESCC tissue microarray contained 116 pairs of ESCC and normal tissues and 73 single ESCC tissues. VDR expression and its clinicopathological role were determined by real-time quantitative polymerase chain reaction, Western blot, and immunohistochemistry staining. sh-VDR and VDR overexpression were used to validate the effect of VDR on ESCC cell phenotype, and tandem mass tag-based quantitative proteomics and bioinformatics methods identified differential VDR-related proteins. The downstream pathway and regulatory effect were analyzed using ingenuity pathway analysis (IPA). Differentially expressed proteins were verified through parallel reaction monitoring and Western blot. In vivo imaging visualized subcutaneous tumor growth following tail vein injection of VDR-deficient ESCC cells. ResultsHigh VDR expression was observed in ESCC tissues and cells. Gender, T stage, and TNM stage were related to VDR expression, which was the independent prognostic factor related to ESCC. VDR downregulation repressed ESCC cell proliferation, invasion, and migration in vitro and subcutaneous tumor growth and lung metastases in vivo. The cell phenotype changes were reversed upon VDR upregulation, and differential proteins were mainly enriched in the p53 signaling pathway. TP53 cooperated with ABCG2, APOE, FTH1, GCLM, GPX1, HMOX1, JUN, PRDX5, and SOD2 and may activate apoptosis and inhibit oxidative stress, cell metastasis, and proliferation. TP53 was upregulated after VDR knockdown, and TP53 downregulation reversed VDR knockdown-induced cell phenotype changes. ConclusionsVDR may inhibit p53 signaling pathway activation and induce ESCC proliferation, invasion, and metastasis by activating oxidative stress.

188. VITAMIN D RECEPTOR INDUCES OXIDATIVE STRESS TO PROMOTE ESOPHAGEAL SQUAMOUS CELL CARCINOMA PROLIFERATION VIA THE P53 SIGNALING PATHWAY

Abstract Background Esophageal squamous cell carcinoma (ESCC) is a common pathological esophageal cancer with poor prognosis. Vitamin D deficiency reportedly occurs in ESCC patients, and this is related to single nucleotide polymorphism of vitamin D receptor (VDR). We investigated the effect of VDR on ESCC proliferation, invasion, and metastasis and its potential mechanism. Methods ESCC and normal tissues were collected from 20 ESCC patients. The ESCC tissue microarray contained 116 pairs of ESCC and normal tissues and 73 single ESCC tissues. VDR expression and its clinicopathological role were determined by real-time quantitative polymerase chain reaction, western blot, and immunohistochemistry staining. sh-VDR and VDR overexpression were used to validate the effect of VDR on ESCC cell phenotype, and tandem mass tag-based quantitative proteomics and bioinformatics methods identified differential VDR-related proteins. The downstream pathway and regulatory effect were analyzed using ingenuity pathway analysis (IPA). Differentially expressed proteins were verified through parallel reaction monitoring and western blot. In vivo imaging visualized subcutaneous tumor growth following tail vein injection of VDR-deficient ESCC cells. Results High VDR expression was observed in ESCC tissues and cells. Gender, T stage, and TNM stage were related to VDR expression, which was the independent prognostic factor related to ESCC. VDR downregulation repressed ESCC cell proliferation, invasion, and migration in vitro and subcutaneous tumor growth and lung metastases in vivo. The cell phenotype changes were reversed upon VDR upregulation, and differential proteins were mainly enriched in the p53 signaling pathway. TP53 cooperated with ABCG2, APOE, FTH1, GCLM, GPX1, HMOX1, JUN, PRDX5, and SOD2 and may activate apoptosis and inhibit oxidative stress, cell metastasis, and proliferation. TP53 was upregulated after VDR knockdown, and TP53 downregulation reversed VDR knockdown-induced cell phenotype changes. Conclusions VDR may inhibit p53 signaling pathway activation and induce ESCC proliferation, invasion, and metastasis by activating oxidative stress.

MiR-874-5p targets VDR/NLRP3 to reduce intestinal pyroptosis and improve intestinal barrier damage in sepsis.

Vitamin D receptor (VDR) is associated with intestinal barrier damage in sepsis. However, the mechanism of action of miR-874-5p/VDR/NLRP3 axis in disease has not been clearly explained. Therefore, the main content of this study is to explore the mechanism of this axis in intestinal barrier damage in sepsis. In order to confirm the progress of miR-874-5p regulation of VDR/NLRP3 pathway and its involvement in intestinal barrier damage in sepsis, a series of molecular biology and cell biology methods were carried out in this study. These include the establishment of cecal ligation puncture model, Western blot, RT-qPCR, hematoxylin and eosin staining, double luciferase reporting method, Fluorescence in situ hybridization, immunohistochemistry, and enzyme-linked immunosorption assay. The expression level of miR-874-5p was higher and that of VDR was lower in sepsis. miR-874-5p was negatively correlated with VDR. Inhibition of miR-874-5p expression increased the expression of VDR, decreased the expression of NLRP3, reduced caspase-1 activation and IL-1β secretion, reduced pyroptosis and inflammatory response, and thus protected the intestinal barrier damage in sepsis, all of which were reversed by the downregulation of VDR. This study suggested that down-regulation of miR-874-5p or up-regulation of VDR could reduce intestinal barrier damage in sepsis, which may provide potential biomarkers and therapeutic targets for intestinal barrier damage in sepsis.

Exploring the Role of Vitamin D and the Vitamin D Receptor in the Composition of the Gut Microbiota.

The microbiome has a major impact on human physiology and plays a critical role in enhancing or impairing various physiological functions such as regulation of the immune system, metabolic activities, and biosynthesis of vitamins and hormones. Variations in the gut microbial community play a critical role in both health and disease. Regulation of calcium and bone metabolism, as well as cellular functions such as proliferation, apoptosis, differentiation, and immune modulation, are among the known effects of vitamin D. These biological functions are primarily carried out through the binding of vitamin D to the vitamin D receptor (VDR), a member of the nuclear receptor superfamily. The immunomodulatory properties of vitamin D suggest that this molecule plays an important role in various diseases. Maintenance of immune homeostasis appears to occur in part through the interaction of the gut microbiota with vitamin D. Increasing evidence points to the central role of vitamin D in maintaining mucosal barrier function, as vitamin D deficiency has been associated with disruption of gut barrier integrity, translocation of bacteria into the bloodstream, and systemic inflammation. In parallel, a bidirectional interaction between vitamin D and the gut microbiota has been demonstrated as data show upregulation of intestinal VDR expression and downregulation of inflammatory markers in response to fermentation products. The aim of this review is to provide an overview of the evidence of a link between the gut microbiome and vitamin D, with a focus on data from experimental models and translational data from human studies related to vitamin D-induced changes in gut microbiota composition.

MicroRNA-125b mediates Interferon-γ-induced downregulation of the vitaminD receptor in systemic lupus erythematosus.

The inflammatory factor interferon (IFN)-γ is related to the occurrence and development of systemic lupus erythematosus (SLE). The vitaminD receptor (VDR) has an anti-inflammatory effect and its downregulation is involved in the onset of SLE. Our previous studies have confirmed that the expression of VDR in SLE peripheral blood mononuclear cells (PBMCs) is downregulated, which is negatively correlated with disease activity and inflammation. However, the mechanism underlying VDR downregulation in SLE is unknown. Based on the results of computer simulation analysis, the expression of VDR and four microRNAs (miR-17-3p, miR-34a, miR-346, and miR-125b) in SLE PBMC cells was analyzed under proinflammatory cytokine IFN‑γ treatment, and miR-125b was identified as the target miRNA. The relationship between IFN‑γ, miR-125b, and VDR was further assessed in THP‑1 cells. We showed that IFN‑γ inhibited the expression of VDR and miR-125b. Further study revealed that VDR mRNA was positively correlated with miR-125b in THP‑1 cells after IFN‑γ intervention. After transfection of miR-125b mimic or inhibitor, the expression of VDR in the miR-125b inhibitor group was lower than in the control group and miR-125b mimic group, while expression in the control group was lower than in miR-125b mimic group. Transfection of miR-125b inhibitor into THP‑1 cells could further promote the ability of IFN‑γ to inhibit VDR. The decrease in VDR expression promotes development of inflammation and SLE. These data suggest that miR-125b may mediate inflammatory factor IFN-γ-induced downregulation of VDR in the pathogenesis of SLE.

Human Cytomegalovirus Induces Vitamin-D Resistance In Vitro by Dysregulating the Transcriptional Repressor Snail.

Vitamin-D supplementation is considered to play a beneficial role against multiple viruses due to its immune-regulating and direct antimicrobial effects. In contrast, the human cytomegalovirus (HCMV) has shown to be resistant to treatment with vitamin D in vitro by downregulation of the vitamin-D receptor. In this study, we aimed to elucidate the mechanism and possible biological consequences of vitamin-D resistance during HCMV infection. Mechanistically, HCMV induced vitamin-D resistance by downregulating the vitamin-D receptor (VDR) within hours of lytic infection. We found that the VDR was inhibited at the promoter level, and treatment with histone deacetylase inhibitors could restore VDR expression. VDR downregulation highly correlated with the upregulation of the transcriptional repressor Snail1, a mechanism likely contributing to the epigenetic inactivation of the VDR promoter, since siRNA-mediated knockdown of Snail partly restored levels of VDR expression. Finally, we found that direct addition of the vitamin-D-inducible antimicrobial peptide LL-37 strongly and significantly reduced viral titers in infected fibroblasts, highlighting VDR biological relevance and the potential of vitamin-D-inducible peptides for the antiviral treatment of vitamin-D deficient patients.

Vitamin D Receptor/Vitamin D Response Element Directly Modulate Nestin Transcription to Ameliorate PAN-Induced Podocyte Morphological Changes

Background: The change of podocyte morphology is a pathologic feature of chronic kidney disease. Several studies have suggested that vitamin D plays a role in the protection of podocytes, but the underlying mechanism remains unclear. Methods: The effects of paricalcitol on podocyte injury were tested in a puromycin aminonucleoside (PAN)-induced rat model and cultured mouse podocytes. Proteinuria, podocyte foot process (FP) effacement, and the expression of nestin and vitamin D receptor (VDR) were evaluated. VDR-siRNA or plasmids containing VDR-shRNA were transfected into podocytes to silence VDR expression. Chromatin immunoprecipitation (ChIP) and luciferase reporter assays were performed to verify the connection between VDR and nestin gene expression. Results: Paricalcitol significantly alleviated proteinuria and podocyte FP effacement in PAN-induced nephrosis, which was accompanied by increased VDR expression in the glomeruli. Paricalcitol also inhibited PAN-induced nestin overexpression in the glomeruli. In an in vivo study, PAN significantly inhibited VDR protein expression, stimulated nestin protein expression, and resulted in nestin filament derangement in mouse podocytes, while paricalcitol treatment abolished these effects. In contrast, downregulation of VDR resulted in derangement and overexpression of nestin. ChIP assays demonstrated the presence of a vitamin D response element (VDRE) in the nestin promoter, and paricalcitol enhanced the binding of VDR to VDRE. Furthermore, luciferase reporter assays of the nestin promoter fragment showed that paricalcitol effectively repressed nestin reporter gene expression after PAN treatment, and mutation of VDRE abolished this effect. Conclusions: Paricalcitol directly regulates nestin transcription through the interaction of VDR/VDRE, thereby preventing morphological changes of podocytes in PAN nephropathy.

Signaling of vitamin D receptor, 1 alpha-hydroxylase and RANTES genes in dairy cows with hypocalcaemia

The aim of the current study focused on screening the signal of the vitamin D receptor (VDR), 1-alpha-hydroxylase (1α-OHase) enzyme, and chemokine regulated on activation, normal T-cell expressed and secreted (RANTES) genes in dairy cows with hypocalcaemia. A sample of 120 dairy cows (20 dairy cows per herd) in the transition period was studied. Blood samples were drawn from the selected dairy cows for both biochemical and molecular analysis. In cows with subclinical and clinical hypocalcemia, there was a significant (P<0.05) down-regulation of both VDR and RANTES genes, whereas there was a significant (P<0.05) up-regulation of the 1α-OHase enzyme. Moreover, there was a significant (P<0.05) increase in the levels of glucose, parathyroid hormone (PTH), sodium (Na), and chloride (Cl). Furthermore, there was a significant (P<0.05) decrease in the levels of phosphorous and potassium (K). On the animal level, there was a significant association between the expression pattern of the VDR gene and the cows’ breed, the cows’ age, parity number, body condition score, and history of previous transition period disorders. The increase in both the expression of 1α-OHase enzyme and the level of each of PTH, glucose, Na, and Cl in the serum were significant risk factors for the decreased expression of the VDR gene. Likewise, the decrease in both the expression of the RANTES gene and the level of calcium (Ca) and phosphorous in the serum were significant risk factors for decreased expression of the VDR gene. This study revealed that the expression of VDR, 1α-OHase enzyme, and RANTES genes in the blood was greatly affected in dairy cows with hypocalcemia, indicating the need for an extra dose of vitamin D to maintain the normal level of Ca in the blood, especially during periods of high need. Hence, this study provides an insight into the role of vitamin D and its related enzymes in promoting the productivity of dairy cows, especially during the critical production periods.

Calcitriol Alleviates MPP+- and MPTP-Induced Parthanatos Through the VDR/PARP1 Pathway in the Model of Parkinson's Disease.

The pathogenesis of Parkinson’s disease (PD) is currently unclear. Recent studies have suggested a correlation between vitamin D and PD. Vitamin D and its analogs have protective effects in animal models of PD, but these studies have not clarified the mechanism. Parthanatos is a distinct type of cell death caused by excessive activation of poly (ADP-ribose) polymerase-1 (PARP1), and the activation of PARP1 in PD models suggests that parthanatos may exist in PD pathophysiology. 1,25-Dihydroxyvitamin D3 (calcitriol) is a potential inhibitor of PARP1 in macrophages. This study aimed to investigate whether calcitriol treatment improves PD models and its effects on the parthanatos pathway. A 1-methyl-4-phenylpyridinium (MPP+)-induced cell model and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) subacute animal model were selected as the in vitro and in vivo PD models, and calcitriol was applied in these models. Results showed that parthanatos existed in the MPP+-induced cell model and pretreatment with calcitriol improved cell viability, reduced the excessive activation of PARP1, and relieved parthanatos. The application of calcitriol in the MPTP subacute animal model also improved behavioral tests, restored the damage to dopamine neurons, and reduced the activation of PARP1-related signaling pathways. To verify whether calcitriol interacts with PARP1 through its vitamin D receptor (VDR), siRNA, and overexpression plasmids were used to downregulate or overexpress VDR. Following the downregulation of VDR, the expression and activation of PARP1 increased and PARP1 was inhibited when VDR was overexpressed. Coimmunoprecipitation verified the combination of VDR and PARP1. In short, calcitriol can substantially improve parthanatos in the MPP+-induced cell model and MPTP model, and the protective effect might be partly through the VDR/PARP1 pathway, which provides a new possibility for the treatment of PD.

Vitamin D stimulates miR-26b-5p to inhibit placental COX-2 expression in preeclampsia

Vitamin D insufficiency or deficiency during pregnancy has been associated with an increased risk of preeclampsia. Increased placental cyclooxygenase-2 (COX-2) activity was proposed to contribute to the inflammatory response in preeclampsia. This study was to investigate if vitamin D can benefit preeclampsia by inhibiting placental COX-2 expression. Placenta tissues were obtained from 40 pregnant women (23 normotensive and 17 preeclampsia). miR-26b-5p expression was assessed by quantitative PCR. Vitamin D receptor (VDR) expression and COX-2 expression were determined by immunostaining and Western blot. HTR-8/SVneo trophoblastic cells were cultured in vitro to test anti-inflammatory effects of vitamin D in placental trophoblasts treated with oxidative stress inducer CoCl2. 1,25(OH)2D3 was used as bioactive vitamin D. Our results showed that reduced VDR and miR-26b-5p expression, but increased COX-2 expression, was observed in the placentas from women with preeclampsia compared to those from normotensive pregnant women. Transient overexpression of miR-26b-5p attenuated the upregulation of COX-2 expression and prostaglandin E2 (PGE2) production induced by CoCl2 in placental trophoblasts. 1,25(OH)2D3 treatment inhibited CoCl2-induced upregulation of COX-2 in placental trophoblasts. Moreover, miR-26b-5p expression were significantly upregulated in cells treated with 1,25(OH)2D3, but not in cells transfected with VDR siRNA. Conclusively, downregulation of VDR and miR-26b-5p expression was associated with upregulation of COX-2 expression in the placentas from women with preeclampsia. 1,25(OH)2D3 could promote miR-26b-5p expression which in turn inhibited COX-2 expression and PGE2 formation in placental trophoblasts. The finding of anti-inflammatory property by vitamin D through promotion of VDR/miR-26b-5p expression provides significant evidence that downregulation of vitamin D/VDR signaling could contribute to increased inflammatory response in preeclampsia.

MicroRNA-122 contributes to lipopolysaccharide-induced acute kidney injury via down-regulating the vitamin D receptor in the kidney.

Our previous studies showed that vitamin D receptor (VDR) depletion promotes lipopolysaccharide (LPS)-induced acute kidney injury (AKI) in mice, and renal VDR is down-regulated in AKI, but the mechanism of VDR down-regulation is unclear. Nutritional vitamin D deficiency was induced by feeding mice a vitamin D-deficient (VD-D) diet. Mice were injected intraperitoneally with LPS (20mg/kg) to establish LPS-induced AKI. Levels of VDR and miR-122 were measured both in vivo and in vitro. The associations between VDR and miR-122 were analysed by dual-luciferase reporter assays. Compared with vitamin D-sufficient (VD-S) mice, VD-D mice developed more severe renal injury following LPS challenge. LPS induced a dramatic decrease in VDR expression and marked induction of miR-122 both in vivo and in vitro. Furthermore, miR-122 hairpin inhibitor alleviated LPS-induced VDR down-regulation whereas miR-122 mimic directly suppressed VDR expression in HK-2 cells. In luciferase reporter assays, miR-122 mimic was able to suppress luciferase activity in 293T cells co-transfected with a luciferase reporter that contains a putative miR-122 target site from 3'UTR of the VDR transcript, but not when this site was mutated. Moreover, miR-122 mimic significantly blocked paricalcitol-induced luciferase activity in 293T cells co-transfected with a VDRE-driven luciferase reporter, whereas miR-122 hairpin inhibitor enhanced paricalcitol's activity to suppress PUMA and caspase 3 activation induced by LPS in HK-2 cells. Collectively, these studies provide evidence that miR-122 directly targets VDR in renal tubular cells, which strongly suggest that miR-122 up-regulation in the kidney under LPS challenge contributes to kidney injury by down-regulating VDR expression.

The Interventional Effects of Tubson-2 Decoction on Ovariectomized Rats as Determined by a Combination of Network Pharmacology and Metabolomics.

Post-menopausal osteoporosis (PMOP) is associated with estrogen deficiency and worldwide, is becoming increasingly more prevalent in aging women. Various anti-PMOP drugs have been developed to reduce the burden of PMOP; generally, these drugs are efficacious, but with some adverse side effects. Tubson-2 decoction (TBD), a popular traditional Mongolian medicine, has been used to treat PMOP for centuries. However, the precise mechanisms underlying the action of TBD on PMOP have yet to be fully elucidated. Herein, we combined network pharmacology with untargeted metabolomics to identify the key targets and metabolic pathways associated with the interventional effects of TBD on ovariectomized (OVX) rats. Furthermore, we investigated the bone histomorphometry of eight different groups of rats to evaluate the therapeutic effect of TBD. First, we established a TBD-target/PMOP network via network pharmacology; this network identified three key protein targets—vitamin D receptor (VDR), cytochrome P450 19A1 (CYP19A1), and 11β-hydroxysteroid dehydrogenase type 1 (HSD11B1). Morphological analysis showed that severe impairment of the bone micro-architecture in OVX rats could be improved by TBD administration. The TBD-treated rats had a significantly lower bone surface-to-tissue volume (BS/TV) and a significantly smaller trabecular separation (Tb·Sp.) (P<0.05) than the OVX rats; in contrast, bone volume fraction (BVF), trabecular thickness (Tb·Th.), trabecular number (Tb·N.), and bone mineral density (BMD) were significantly higher in the TBD-treated rats (P<0.05). Multivariate and univariate analysis showed that OVX resulted in significant alterations in the concentrations of 105 metabolites and 11 metabolic pathways (P<0.05); in addition, 26 potential biomarkers were identified to investigate the progression of PMOP. Network pharmacology showed that major alterations in vitamin B6 metabolism were associated with the VDR target. Next, we validated the three crucial targets (VDR [P<0.01], HSD11B1 [P<0.01], and CYP19A1 [P<0.05]) by enzyme-linked immunosorbent assays (ELISAs) and demonstrated that the levels of these targets were elevated in the OVX group but reduced in the TBD-treatment group. Collectively, our results suggest that the interventional effects of TBD on OVX rats are likely to be associated with the down regulation of VDR. Our findings enhance our molecular understanding of the interventional effects of TBD on PMOP and will allow us to develop further TBD studies.

Differential distribution in vitamin D receptor gene variants and expression profile in Northeast Brazil influences upon active pulmonary tuberculosis.

Tuberculosis is an infectious disease with variable outcomes. This variability is due to host immune capacity in containing the infection process initiated by the Mycobacterium tuberculosis (MTB). Vitamin D is able to modulate a very specific immune response against MTB infection, and its action relies on vitamin D receptor (VDR) binding. Altered VDR forms may compromise vitamin D pathway and proper immune response after MTB infection. Herein we assessed the relationship of five potentially functional polymorphisms from VDR: rs2228570 FokI, rs11568820 Cdx-2, rs2248098, rs1540339 and rs4760648, with tuberculosis susceptibility. The SNP rs4760648 T/T was associated with differential susceptibility to tuberculosis (OR = 2.50, 95%CI = 1.20-5.36, p = 0.01). The SNP rs1540339 presented association to both T allele (OR = 0.55, 95%CI = 0.35-0.88, p = 0.01) and the T/T genotype (OR = 0.404, 95%CI = 0.20 - 0.78, p = 0.005). The FokI T allele was identified as associated to diminished susceptibility (OR = 0.67, 95% CI = 0.45-0.99, p = 0.04) to active TB, as well as T/T genotype (OR = 0.15, 95%CI = 0.04-0.45, p = 9.58 × 10-5). We also performed the expression analyses and observed a down-regulation of VDR in patients (-10.717 FC, p = 8.42e-12), and according to the presence of associated FokI SNP, we observed that the C/T and T/T genotypes presence increases VDR expression (+ 1.25 and + 2.35 FC, p = 0.425 and p = 0.506, respectively). This study shows that vitamin D receptor variants can influence upon pulmonary tuberculosis susceptibility and VDR mRNA levels are decreased in those patients.

The clinical significance of VDR and WIFI downregulation in colorectal cancer tissue

BackgroundActivation of the Wnt/β catenin signaling pathway is the first event in the majority of colorectal cancers. Wnt inhibitory factor 1 (WIF1) inhibits the activity Wnt/β catenin pathway and prevents tumor growth through binding Wnt ligands. Vitamin D Receptor (VDR) modulates the transcription rate hundreds of target genes, specifically those involved in the inhibition of the Wnt/β catenin pathway. In this study, we aimed to analyze the expression of VDR and WIFI in patients with sporadic CRC. MethodsOur study population consisted of 47 sporadic CRC tissues and their neighboring non-cancerous tissues that were collected between 2006 and 2015. RNA extraction was performed by RNX-plus Total RNA Isolation Kit from tissues. After cDNA synthesis; the real-time PCR was performed to detect VDR and WIFI gene expression. ResultsOur experiments revealed the mRNA expression levels of VDR and WIF1 were markedly lower in tumoral tissues in compared their marginal tissues, especially in the stage of III and stage IV (p-value <0.0001). In addition, there was statistically a positive correlation between VDR and WIFI expressions in tumoral tissues (r = 0.9329, p-value < 0.0001). ConclusionOur findings indicated that expression levels of VDR and WIF1 was low in CRC tissues in comparison with marginal tissues. Thereby, VDR and WIFI may be considered as critical factors which may be associated with different stages of CRC, and it can be novel biomarkers for the diagnosis and prognosis of CRC, as well as can be a promising therapeutic target in CRC.

Vitamin D receptor is negatively correlated with interferon-γ-inducible protein-10 in systemic lupus erythematosus with renal involvement

The vitamin D receptor (VDR) plays an important role in the pathogenesis of systemic lupus erythematosus (SLE) mainly due to its anti-inflammatory and immunomodulatory activities. Interferon-inducible protein-10 (IP-10) is a chemokine found to be increased in SLE patients and correlated with severity of lupus nephritis. In this case control study, we investigated the connection between VDR expression and chemokine IP-10 in peripheral blood mononuclear cells (PBMCs) of SLE patients with or without renal involvement. 62 SLE patients and 30 healthy subjects were enrolled between 2014 and 2016. PBMC VDR mRNA and IP-10 mRNA were quantified by real-time PCR. PBMC VDR protein was measured by Western blotting. PBMC VDR mRNA and protein were downregulated, whereas IP-10 mRNA was upregulated in SLE patients with renal involvement. VDR mRNA levels were negatively correlated with systemic lupus international collaborating clinics (SLICC) renal activity scores (r = −0.423, P = 0.016) and IP-10 mRNA levels (r = −0.428, P = 0.008) in SLE with renal involvement. This study demonstrates that PBMC VDR was negatively correlated with SLICC renal activity and chemokine IP-10 in SLE patients with renal involvement which suggests that VDR downregulation may be used as an indicator of renal injury in SLE patients.

Gentamicin Targets Acid Sphingomyelinase in Cancer: The Case of the Human Gastric Cancer NCI-N87 Cells.

Emerging literature implicates acid sphingomyelinase in tumor sensitivity/resistance to anticancer treatments. Gentamicin is a drug commonly used as an antimicrobial but its serendipity effects have been shown. Even though many evidences on the role of gentamicin in cancer have been reported, its mechanism of action is poorly understood. Here, we explored acid sphingomyelinase as a possible new target of gentamicin in cancer. Since gastric cancer is one of the most common cancers and represents the second cause of death in the world, we performed the study in NCI-N87 gastric cancer cell line. The effect of the drug resulted in the inhibition of cell proliferation, including a reduction of cell number and viability, in the decrease of MIB-1 proliferative index as well as in the upregulation of cyclin-dependent kinase inhibitor 1A and 1B (CDKN1A and CDKN1B), and growth arrest and DNA-damage 45A (GADD45A) genes. The cytotoxicity was apoptotic as shown by FACS analysis. Additionally, gentamicin reduced HER2 protein, indicating a minor tumor aggressiveness. To further define the involvement of sphingomyelin metabolism in the response to the drug, gene and protein expression of acid and neutral sphingomeylinase was analyzed in comparison with phosphatase and tensin homolog deleted on chromosome 10 (PTEN) and vitamin D receptor (VDR), molecules involved in cancer. Gentamicin induced a downregulation of PTEN, VDR, and neutral sphingomyelinase and a strong upregulation of acid sphingomyelinase. Of note, we identified the same upregulation of acid sphingomyelinase upon gentamicin treatment in other cancer cells and not in normal cells. These findings provide new insights into acid sphingomyelinase as therapeutic target, reinforcing studies on the potential role of gentamicin in anticancer therapy.

Vitamin D receptor expression in peripheral blood mononuclear cells is inversely associated with disease activity and inflammation in lupus patients

Systemic lupus erythematosus (SLE) is characterized by uncontrolled production of pro-inflammatory cytokines. Vitamin D receptor (VDR) has potent anti-inflammatory activities. The aim of this study was to examine the correlation between VDR expression and inflammation and disease activity in patients with SLE. Ninety-five SLE patients were recruited and divided into two groups, active and inactive, according to their SLE disease activity index (SLEDAI)-2K, and 40 healthy individuals served as controls. The expression of VDR and NF-κB p65 in peripheral blood mononuclear cells (PBMCs) was determined by quantitative RT-PCR and Western blotting. VDR expression was correlated with inflammatory and diseases parameters in SLE patients. VDR regulation was also studied in THP-1 and Jurkat cell lines. PBMC VDR expression was downregulated in SLE patients, especially in the active SLE group. VDR mRNA levels were negatively correlated with SLEDAI-2K (r = - 0.348, P = 0.001), Systemic Lupus International Collaborating Clinics (SLICC) renal activity scores (r = - 0.346, P = 0.014), and proteinuria (r = - 0.309, P = 0.002) and positively associated with serum complement C3 levels (r = 0.316, P = 0.002). Multiple stepwise regression analysis indicated that PBMC VDR downregulation was an independent risk factor for SLEDAI-2K. VDR levels were also negatively correlated with NF-κB p65 (r = - 0.339, P = 0.001), TNF-α (r = - 0.268, P = 0.009), and IL-6 (r = - 0.313, P = 0.002) levels. In monocyte and T lymphocyte cell lines, TNF-α suppressed VDR expression, whereas 1,25-dihydroxyvitamin D blocked TNF-α-induced VDR downregulation. PBMC VDR expression is inversely associated with disease activity and inflammation in SLE patients, and VDR downregulation is likely driven by inflammation.

Vitamin D Deficiency in the Gulf Cooperation Council: Exploring the Triad of Genetic Predisposition, the Gut Microbiome and the Immune System.

Vitamin D is a fat soluble secosteroid that is primarily synthesized in the skin upon exposure to Ultraviolet B (UVB) sun rays. Vitamin D is essential for the growth and development of bones and helps in reducing inflammation by strengthening muscles and the immune system. Despite the endless supply of sunlight in the Gulf Cooperation Council (GCC) countries which includes United Arab Emirates, Qatar, Kuwait, Bahrain, Saudi Arabia, and Oman, Vitamin D deficiency in the (GCC) general population at various age groups remains alarmingly high. In parallel runs the increasing prevalence of acute and chronic illnesses including, autoimmune diseases, cancer, type 1 diabetes mellitus, cardiovascular disease and Inflammatory bowel disease in the adult as well as the pediatric population of these countries. The exact association between Vitamin D deficiency and chronic disease conditions remains unclear; however, studies have focused on the mechanism of Vitamin D regulation by assessing the role of the Vitamin D associated genes/proteins such as VDR (Vitamin D receptor), VDBP (Vitamin D Binding protein), CYP27B1 as these are integral parts of the Vitamin D signaling pathway. VDR is known to regulate the expression of more than 200 genes across a wide array of tissues in the human body and may play a role in controlling the Vitamin D levels. Moreover, reduced Vitamin D level and downregulation of VDR have been linked to gut dysbiosis, highlighting an intriguing role for the gut microbiome in the Vitamin D metabolism. However, this role is not fully described yet. In this review, we aim to expand our understanding of the causes of Vitamin D deficiency in the GCC countries and explore the potential relationship between the genetic predisposition, Vitamin D levels, immune system and the gut microbiome composition. Trying to unravel this complex interaction may aid in understanding the mechanism by which Vitamin D contributes to various disease conditions and will pave the way toward new therapeutics treatments for Vitamin D deficiency and its associated outcomes.

LPS-induced Vitamin D Receptor Decrease in Oral Keratinocytes Is Associated With Oral Lichen Planus

The suppressive function of vitamin D on oral lichen planus (OLP) have been documented previously. Vitamin D receptor (VDR) expression is down-regulated in OLP, but the molecular mechanism of its decrease and the related anti-inflammatory contributor of epithelial VDR signaling is unclear. Herein, we demonstrated that lipopolysaccharide (LPS) remarkedly down-regulated VDR expression of keratinocytes, and the reduced regulation was dependent on tumor necrosis factor alpha (TNFα)-miR-346 pathway. In human specimen studies, VDR levels of oral mucosal epithelia from OLP patients decreased substantially accompanied with robust TNFα and miR-346 induction, compared to the normal tissues. In addition, vitamin D/VDR signaling inhibited LPS-induced p53-upregulated modulator of apoptosis (PUMA) induction in keratinocytes via impeding nuclear factor-κB (NF-κB) activation, resulting in keratinocytes apoptosis reduction. Importantly, PUMA activity was up-regulated strongly in diseased epithelium, reversely correlated with VDR expression. Totally, our data indicate that LPS is responsible for VDR downregulation in oral keratinocytes, which is associated with OLP development.

Gut Epithelial Vitamin D Receptor Regulates Microbiota-Dependent Mucosal Inflammation by Suppressing Intestinal Epithelial Cell Apoptosis.

Recent studies show that colonic vitamin D receptor (VDR) signaling protects the mucosal epithelial barrier and suppresses colonic inflammation, but the underlying molecular mechanism remains to be fully understood. To investigate the implication of colonic VDR downregulation seen in patients with inflammatory bowel disease, we assessed the effect of gut epithelial VDR deletion on colonic inflammatory responses in an experimental colitis model. In a 2,4,6-trinitrobenzenesulfonic acid-induced colitis model, mice carrying VDR deletion in gut epithelial cells [VDRflox/flox (VDRf/f);Villin-Cre or VDRΔIEC] or in colonic epithelial cells (VDRf/f;CDX2-Cre or VDRΔCEC) developed more severe clinical colitis than VDRf/f control mice, characterized by more robust T-helper (TH)1 and TH17 responses, with greater increases in mucosal interferon (IFN)-γ+, interleukin (IL)-17+, and IFN-γ+IL-17+ T cells. Accompanying the severe mucosal inflammation was more profound colonic epithelial cell apoptosis in the mutant mice. Treatment with caspase inhibitor Q-VD-OPh dramatically reduced colitis severity and attenuated TH1 and TH17 responses in VDRΔCEC mice. The blockade of cell apoptosis also prevented the increase in mucosal CD11b+CD103+ dendritic cells (DCs), known to be critical for TH17-cell activation. Moreover, depletion of gut commensal bacteria with antibiotics eliminated the robust TH1 and TH17 responses and CD11b+CD103+ DC induction. Taken together, these observations demonstrate that gut epithelial VDR deletion aggravates epithelial cell apoptosis, resulting in increases in mucosal barrier permeability. Consequently, invading luminal bacteria activate CD11b+CD103+ DCs, which promote mucosal TH1 and TH17 responses. Therefore, gut epithelial VDR signaling controls mucosal inflammation by suppressing epithelial cell apoptosis.