Vitamin D Receptor Expression Levels Research Articles

Vitamin D3/VDR alleviates double-stranded RNA virus -induced biliary epithelial cell damage by inhibiting autophagy

BackgroundThe increased apoptosis of bile duct epithelial cells (BECs) due to some damage factors is considered the initiating factor in the occurrence and progression of biliary atresia (BA). Vitamin D receptor (VDR) is thought to play a crucial role in maintaining the intrinsic immune balance and integrity of bile duct epithelial cells (BECs). To investigate the role of VDRs in the pathogenesis and progression of BA using in vitro and in vivo models.Materials and methodsThe VDR expression levels in intrahepatic bile duct epithelial cells (IBDECs) in pediatric patients with BA were examined using immunohistochemical analysis. The correlation of the VDR levels with the incidence of refractory cholangitis after Kasai portoenterostomy (KPE) and the autologous liver survival time was analyzed. The levels of genes and proteins involved in related pathways were examined using quantitative real-time polymerase chain reaction and western blotting, respectively. The secretory levels of inflammatory factors were analyzed using enzyme-linked immunosorbent assay. A BA mouse model was established through the intraperitoneal sequential injection of rhesus rotavirus (RRV). The role of VDR in the pathogenesis and progression of BA was examined using in vitro and in vivo models. Retrospective analysis of patients with BA to examine the therapeutic efficacy of VDR activators on BA.Results15 pediatric BA patients exhibiting VDR downregulation in IBDECs showed a higher incidence of refractory cholangitis after Kasai portoenterostomy (p = 0.037) and a lower native liver survival time compare to 23 BA patients without VDR downregulation (p = 0.032). 1,25-VD3 inhibited the degree of autophagy induction in HIBECs by poly(I: C) (p < 0.05), mitigated poly(I: C)-induced BEC damage and apoptosis by inhibiting autophagy (p < 0.05). 1,25-VD3 significantly suppressed the poly(I: C)-induced downregulation of SRC (p < 0.05) and ERK1/2 phosphorylation (p < 0.05). 1,25-VD3 exert a protective effect against RRV-induced BEC damage by inhibiting autophagy in BA mouse model. The incidence of cholangitis and the native liver survival time after surgery in the calcitriol-treated group was significantly lower than that in the control group. (p = 0.033, p = 0.035, respectively).ConclusionsVDR activator mitigated dsRNA-induced BEC damage and apoptosis by inhibiting autophagy in vitro and in vivo. The 1,25-VD3/VDR/Src axis alleviated poly(I: C)-induced HIBEC damage and apoptosis through the PLA2/PKC/ERK pathway.Graphical abstract

A study of the association of vitamin D receptor (VDR) as a predictive biomarker for immune checkpoint inhibitor therapy with immune invasion in colon adenocarcinoma

Colon adenocarcinoma(COAD) is a primary and aggressive malignancy with the fifth highest mortality rate among cancers, and it is important to discover new strategies. The online database was used to analyze the correlation between Vitamin D receptor (VDR) and COAD, and further explore the immune infiltration and related gene networks.The expression and methylation levels of VDR was analyzed by using Timer database, GEPIA platform and UALCAN database. GeneMANIA database was used to analyze and obtain gene networks that are closely linked to VDR. UALCAN database was used to score the gene effects of VDR in colorectal cancer cell lines. The cBioPortal database was used for the detection of gene mutations. The survival curve analysis was carried out using the GEPIA database. The relationship between VDR expression and immune cell infiltration was analyzed by using the timer database and TISIDB database. TISIDB database was used to obtain VDR-related drug targets.The expression of VDR was significantly lower in COAD(p<0.05). The methylation level of VDR was significantly higher in COAD (p<0.05). The gene mutation rate of VDR in COAD was 2 %. OS and DFS were not associated with changes in the VDR gene in patients with COAD. VDR expression was correlated with CD4+T cell infiltration, macrophage infiltration, neutrophil infiltration, and dendritic cell infiltration. VDR has a clear correlation with ADORA2A, BTLA, CD160, CD244, CD274, CD96, CSF1R, CTLA4, HAVCR2, IL10, IDO1, LAG3, LGALS9, PDCD1, PDCD1LG2, PVRL2, TGFB1, TGFBR1, TIGIT and VTCN1.The expression of VDR is associated with immune infiltration in patients with COAD. VDR may be a new candidate biomarker for determining the level of immune infiltration and predicting immune checkpoint inhibitor therapy.

Dietary vitamin D intake and risk of colorectal cancer according to vitamin D receptor expression in tumors and their surrounding stroma.

Colorectal Cancer (CRC) has been molecularly classified into several subtypes according to tumor, stromal, and immune components. Here, we investigated whether the preventive effect of vitamin D on CRC varies with subtypes defined by Vitamin D receptor (VDR) expression in tumors and their surrounding stroma, along with the association of somatic mutations in CRC. In a population-based prospective study of 22,743 Japanese participants, VDR expression levels in tumors and their surrounding stroma were defined in 507 cases of newly diagnosed CRC using immunohistochemistry. Hazard ratios of CRC and its subtypes according to dietary vitamin D intake were estimated using multivariable Cox proportional hazards models. Dietary vitamin D intake was not associated with CRC or its subtypes defined by VDR expression in tumors. However, an inverse association was observed for CRC with high VDR expression in the stroma (the highest tertile vs the lowest tertile: 0.46[0.23-0.94], Ptrend = 0.03), but not for CRC with low VDR expression in the stroma (Pheterogeneity = 0.02). Furthermore, CRC with high VDR expression in the stroma had more somatic TP53 and BRAF mutations and fewer APC mutations than those with low VDR expression in the stroma. This study provides the first evidence that the preventive effect of vitamin D on CRC depends on VDR expression in the stroma rather than in the tumors. CRC with high VDR expression in the stroma is likely to develop through a part of the serrated polyp pathway, which tends to occur with BRAF but not with APC mutations.

Investigating the level of vitamin D receptor gene expression in two tumoral and healthy breast tissues in breast cancer patients and its association with prognostic factors.

Breast cancer is one of the most common cancers known among women. This study aimed to investigate the level of vitamin D receptor gene expression in two tumoral and healthy breast tissues in breast cancer patients and its association with prognostic factors. This descriptive cross-sectional study was conducted in 2022 on 50 patients with high suspicion of breast cancer who were candidates for mastectomy and lumpectomy in a learning hospital. From the patients, two tissue samples were prepared, and there was a total of 100 samples. The samples were subjected to H/E staining and evaluated by a pathologist. The presence or absence of malignancy in each sample was confirmed by two pathologists, and HER2/ER/PR indices were determined. Descriptive and analytical statistical methods and SPSS version 22 software were used. The average age of the patients was 51.60 ± 11.22 years old, and the average tumor size was 3.17 ± 1.28. Most tumors were grade 2 (48%). The expression of HER2, ER, and PR was positive in 24, 64, and 54%, respectively. The largest number of cases were in stage 2A. The expression level of vitamin D receptor (VDR) gene in healthy tissue (2.08 ± 1.01) was higher than tumoral tissue (0.25 ± 1.38) (P = 0.001). In tumoral and healthy tissue, VDR expression was not significant according to tumor grade, HER2, ER, PR, LVI, LN, disease stage, age, and tumor size. The expression level of VDR in healthy tissue was significantly higher than tumoral tissue. However, there was no significant relationship between VDR and tumor grade, HER2, ER, PR, LVI, LN, disease stage, age, and tumor size.

Expression analysis of vitamin D receptor-associated long noncoding RNAs in patients with relapsing-remittingmultiple sclerosis.

Vitamin D is a neuroactive steroid that carries out its biological functions through the vitamin D receptor (VDR). The VDR gene interacts with certain long noncoding RNAs (lncRNAs). The present study is aimed at evaluating the expression levels of the VDR gene as well as those of HOTAIR, H19, MALAT1, and P21 lncRNAs in patients with relapsing-remitting multiple sclerosis (RRMS). This research was conducted on 38 RRMS patients and 38 healthy individuals. The expression levels of VDR and selected lncRNAs in peripheral blood as well as those of vitamin D in the plasma were measured. The results revealed a significant increase in the expression of lncRNA H19 in the RRMS group compared to the control group. The analysis of the receiver operating characteristic (ROC) curve for H19 gene expression demonstrated a diagnostic value of 0.699 (95% CI: 0.575-0.823). Positive correlations were detected between VDR and lncRNA HOTAIR (r = 0.446, p = 0.008), H19 (r = 0.351, p = 0.042), MALAT1 (r = 0.464, p = 0.006), and P21 (r = 0.512, p = 0.002) in MS patients. The findings of this study suggest that lncRNA H19 could serve as a potential biomarker for MS diagnosis (Tab. 4, Fig. 1, Ref. 34).

The Efficacy of Vitamin D Supplement in the Expression and Protein Levels of Endometrial Decidualization Factors in Women with Recurrent Implantation Failure.

Recurrent implantation failure (RIF) is a challenging situation for infertility specialists, and its treatment is introduced as a difficult case in the field of assisted reproductive technology (ART). Vitamin D (VD) is one of the supplements that have been suggested to improve the implantation process. In the present study, the effect of VD on the expression and protein levels of VD receptor (VDR), progesterone receptor (PR), prolactin (PRL), insulin-like growth factor binding protein-1 (IGFBP-1), and homeobox protein A10 (HOXA10) in the endometrial cells of unknown RIF women with and without VD deficiency were assessed by qRT-PCR and immunohistochemistry. Twelve women with unknown RIF and VD deficiency (≤ 20 ng/ml) and twelve women with unknown RIF without VD deficiency (≥ 30 ng/ml) from 2021 to 2022 were identified. Endometrial specimens were collected in the mid-luteal stage before treatment or pregnancy. In the group with VD deficiency, oral medication of VD 50,000 units was prescribed for 2 to 3 months and their serum levels of VD were re-measured, then an endometrial biopsy at the same stage of the menstrual cycle was performed. The expression and protein levels of VDR, PR, PRL, IGFBP1, and HOXA10 in RIF patients with VD deficiency were lower than the RIF patients without VD deficiency (P value < 0.05). Our findings suggest that VD can play a key role in the pregnancy process, especially during embryo implantation and decidualization of the endometrial cells.IRCT registration number: IRCT20220528055006N1, Registration date: 2022-10-15, Registration timing: retrospective.

TGF-β1 stimulation and VDR-dependent activation modulate calcitriol action on skeletal muscle fibroblasts and Smad signalling-associated fibrogenesis

Fibroblasts play a pivotal role in fibrogenesis after skeletal muscle injury. Excess fibrous formation can disrupt contractile functions and delay functional recovery. Although vitamin D receptor (VDR) is expressed explicitly in regenerating muscle compared with uninjured muscle, how calcitriol [1α,25(OH)2D3] directly regulates skeletal muscle primary fibroblast proliferation, the transition to myofibroblasts, and Smad signalling-associated fibrogenesis is currently unknown. Herein, the effects of calcitriol on cultured skeletal muscle primary fibroblasts of male C57BL/6 mice (aged 1 month old) were investigated. The percentage of BrdU+ nuclei in primary fibroblasts was significantly decreased after calcitriol treatment; however, the antiproliferative effect of calcitriol was diminished after TGF-β1 stimulation to induce fibroblast to myofibroblast transition. This suppressive effect was associated with significantly decreased VDR expression in TGF-β1-treated cells. In addition, Vdr siRNA transfection abolished the effects of calcitriol on the suppression of α-SMA expression and Smad2/3 signalling in myofibroblasts, supporting that its antifibrogenic effect requires VDR activation. Compared with calcitriol, the antifibrotic agent suramin could inhibit fibroblast/myofibroblast proliferation and suppress the expression of TCF-4, which regulates fibrogenic determination. Collectively, these findings suggest that profibrotic stimulation and VDR-dependent activation could modulate the effects of calcitriol on skeletal muscle fibroblast proliferation and fibrogenesis processes. Therefore, TGF-β1 and VDR expression levels are crucial determinants for the antifibrogenic effect of calcitriol on skeletal muscle after injury.

Vitamin D3 suppresses the cholesterol homeostasis pathway in patient-derived glioma cell lines.

Glioblastoma is one of the most common malignant brain tumors. Vitamin D, primarily its hormonally active form calcitriol, has been reported to have anti-cancer activity. In the present study, we used patient-derived glioma cell lines to examine the effect of vitamin D3 and calcitriol on glioblastoma. Surprisingly, vitamin D3 showed a more significant inhibitory effect than calcitriol on cell viability and proliferation. Vitamin D receptor (VDR) mediates most of the cellular effects of vitamin D, and thus we examined the expression level and function of VDR via gene silencing and gene knockout experiments. We observed that VDR does not affect the sensitivity of patient-derived glioma cell lines to vitamin D3, and the gene encoding VDR is not essential for growth of patient-derived glioma cell lines. RNA sequencing data analysis and sterolomics analysis revealed that vitamin D3 inhibits cholesterol synthesis and cholesterol homeostasis by inhibiting the expression level of 7-dehydrocholesterol reductase, which leads to the accumulation of 7-dehydrocholesterol and other sterol intermediates. In conclusion, our results suggest that vitamin D3, rather than calcitriol, inhibits growth of patient-derived glioma cell lines via inhibition of the cholesterol homeostasis pathway.

Effects of evocalcet on parathyroid calcium-sensing receptor and vitamin D receptor expression in uremic rats.

Little is known about the effect of the recently developed calcimimetic evocalcet (Evo) on parathyroid calcium-sensing receptor (CaSR) and vitamin D receptor (VDR) expression. We examined the effects of Evo and cinacalcet (Cina) on CaSR and VDR expression in 5/6 nephrectomized Sprague-Dawley rats fed a high-phosphorus diet for 4 weeks to develop secondary hyperparathyroidism (SHPT). These uremic rats were divided into 4 groups-baseline control (Nx4W) and groups with additional treatment with either the Vehicle, Evo, or Cina for 2 weeks; normal rats were used as normal controls (NC). Blood parameters and parathyroid tissue were analyzed. CaSR and VDR expression levels were determined using immunohistochemistry. The degree of kidney injury and hyperphosphatemia was similar in the uremic groups (Nx4W, Vehicle, Cina, and Evo). Serum parathyroid hormone levels were significantly higher in the Nx4W and Vehicle groups than in the NC group. This increase was significantly suppressed in the Cina and Evo groups compared with that in the Vehicle group. Serum calcium levels were significantly and equally lower in the Cina and Evo groups relative to those in the Vehicle group. CaSR expression was significantly lower in the Nx4W and Vehicle groups than in the NC group. This downregulation was of an equally lesser magnitude in the Cina and Evo groups. A similar trend was observed for VDR expression. These results indicate that Evo and Cina treatment can increase parathyroid CaSR and VDR expression in uremic rats with SHPT, which could provide better control of mineral and bone disorder markers.

The Influence of Single Nucleotide Polymorphisms on Vitamin D Receptor Protein Levels and Function in Chronic Liver Disease.

Single nucleotide polymorphisms (SNPs) in the vitamin D receptor (VDR) gene have been associated with chronic liver disease. We investigated the role of VDR SNPs on VDR protein levels and function in patients with chronic liver disease. VDR expression levels were determined in peripheral T lymphocytes (CD3+VDR+), monocytes (CD14+VDR+), and plasma from patients (n = 66) and healthy controls (n = 38). Genotyping of SNPs and the determination of expression of VDR/vitamin D-related genes were performed by using qPCR. The effect of FokI SNP on vitamin D-binding to VDR was investigated by molecular dynamics simulations. CD14+VDR+ cells were correlated with the MELD score. The ApaI SNP was associated with decreased CD3+VDR+ levels in cirrhotic patients and with higher liver stiffness in HCV patients. The BsmI and TaqI SNPs were associated with increased VDR plasma concentrations in cirrhotic patients and decreased CD14+VDR+ levels in HCV patients. The FokI SNP was associated with increased CD3+VDR+ levels in cirrhotic patients and controls. VDR polymorphisms were significantly related to the expression of genes critical for normal hepatocyte function and immune homeostasis. VDR expression levels were related to the clinical severity of liver disease. VDR SNPs may be related to the progression of chronic liver disease by affecting VDR expression levels.

Hydroxysafflor Yellow A-Induced Osteoblast Differentiation and Proliferation of BM-MSCs by Up-Regulating Nuclear Vitamin D Receptor.

Vitamin D receptor (VDR) is critical for mineral and bone homeostasis since it plays an essential role in the osteoblast differentiation of bone marrow mesenchymal stem cells (BM-MSCs). Hydroxysafflor yellow A (HSYA) has the potential to promote bone mineralization and inhibit bone resorption, while its detailed mechanism needs to be elaborated. This study intends to explore the action of HSYA on the proliferation and differentiation of BM-MSC and the underlying mechanism. Different concentrations of HSYA to BM-MSC and CCK-8, and EdU were used to detect cell viability and proliferation. The alkaline phosphatase (ALP) was used to observe the differentiation ability of BM-MSC osteoblasts. The calcium uptake and mineralization of osteoblast-like cells were observed by alizarin red staining. The level of calcium ion uptake in cells was detected by flow cytometry. AutoDock was performed for molecular docking of HSYA to VDR protein. Immunofluorescence and western blotting were performed to detect the expression of VDR expression levels. Finally, the effect of VDR was verified by a VDR inhibitor. After treatment with HSYA, the proliferation and calcium uptake of BM-MSC were increased. The level of ALP increased significantly and reached its peak on the 12th day. HSYA promoted calcium uptake and calcium deposition, and mineralization of osteoblasts. The western blotting and immunofluorescence showed that HSYA increased the expression of VDR in the osteoblast-like cell's nucleus and upregulated Osteocalcin, S100 calcium-binding protein G, and CYP24A1. In addition, HYSA treatment increased the expression of osteopontin and the synthesis of osteogenic proteins, such as Type 1 collagen. After the addition of the VDR inhibitor, the effect of HSYA was weakened. HSYA could significantly promote the activity and proliferation of osteoblasts and increase the expression level of VDR in osteoblasts. HSYA may also improve calcium absorption by osteoblasts by regulating the synthesis of calciumbinding protein and vitamin D metabolic pathway-related proteins.

The role of vitamin D receptor and IL-6 in COVID-19.

Vitamin D (Vit.D) has an important role in protecting COVID-19 patients. This study investigated the changes in vitamin D receptor (VDR) expression and interleukin 6 levels in patients with COVID-19. 120 hospitalized patients and 120 healthy people participated in this study, both group adjusted by sex and age. Vit.D was measured with HPLC, the expression of VDR gene was done with Real-time PCR, and IL-6 was measured with ELISA assay. Our findings showed no significant difference in the case of Vit.D (25-OH-D3) between the two studied groups, interestingly the expression of VDR was statistically lower in the patients with COVID-19, p-value=0.003. VDR expression was lower in the patient with diabetes, hypertension and cardiovascular disease, significantly, p-value=0.002. The level of IL-6 was statistically higher in the COVID-19 group, p-value=0.003. Alongside the important role of 25-OH-D3 in COVID-19 patients, the quality and quantity of the VDR expression and its role in the level of IL-6 are the promising risk factors in the future. Further studies are needed to determine the factors increasing the expression level of VDR, especially in the patients with diabetes, hypertension and cardiovascular disease.

Role of the Vitamin D Receptor (VDR) in the Pathogenesis of Osteoporosis: A Genetic, Epigenetic and Molecular Pilot Study.

The vitamin D receptor (VDR) regulates bone development and calcium homeostasis, suggesting a central role in musculoskeletal diseases such as osteoporosis (OP). Several studies have examined the contribution of VDR polymorphisms and epigenetic signatures in bone metabolism and OP risk, with sometimes inconclusive results. Our study aimed to explore the association between genetic variability, expression and the methylation pattern of VDR with the risk of OP in a cohort of Caucasian patients. Genomic DNA from 139 OP, 54 osteopenic (Ope) and 73 healthy (CTR) subjects were used for genotyping the rs731236 (TaqI), rs2228570 (FokI) and rs11568820 (Cdx2) polymorphisms of the VDR gene by an allelic discrimination assay. Quantitative real-time polymerase chain reaction (qRT-PCR) analysis of VDR expression levels and pyrosequencing analysis of a VDR promoter CpG island were carried out in a subcohort (25 OP and 25 CTR) of subjects. Data obtained showed a significantly higher OP risk for rs11568820 G/A and A/A genotypes (p = 0.05). qRT-PCR revealed lower VDR gene expression levels in the OP group compared to CTR subjects (p = 0.0009), also associated with both the rs11568820 A/A genotype (p = 0.03) and femoral fragility fractures (p = 0.05). No association was found between the methylation pattern of the region analyzed of the VDR promoter and its expression levels. Our results identify a significative association between Cdx2 rs11568820 polymorphism and OP risk. In addition, the VDR transcriptomic profile suggests a putative interconnection with OP progression, providing a useful tool to stratify OP phenotype and fragility fracture risk.

Clinical efficacy of moxibustion for ulcerative colitis and its influence on vitamin D receptor

ObjectiveTo observe the clinical efficacy of herbal cake-partitioned moxibustion for ulcerative colitis (UC) and elucidate its mechanism by targeting the vitamin D receptor (VDR) signaling pathway.MethodsA total of 63 patients with UC were randomly divided into an observation group (30 cases, treated with herbal cake-partitioned moxibustion) and a control group (33 cases, treated with sham herbal cake-partitioned moxibustion). Moxibustion treatment was performed at Qihai (CV6) and bilateral Tianshu (ST25) and Shangjuxu (ST37), 3 times per week for 12 weeks. The total effective rate, visual analog scale (VAS) score for abdominal bloating and pain, and hospital anxiety and depression scale (HADS) score were compared between the two groups. Enzyme-linked immunosorbent assay was used to detect the concentrations of serum C-reactive protein (CRP), 25-hydroxyvitamin D [25(OH)D], and interleukin-12 (IL-12)/interleukin-23 (IL-23) p40. Immunohistochemistry was used to observe the expression levels of VDR and regenerating gene IV (Reg IV) proteins in colonic mucosa. The expression levels of VDR, cytochrome p450 27B1 (CYP27B1), and Reg IV mRNAs were detected by real-time fluorescence quantitive polymerase chain reaction.ResultsAfter treatment, the total effective rate in the observation group was 86.7%, which was significantly higher than 51.5% in the control group (P<0.05). After treatment, the VAS scores for abdominal bloating and pain in the observation group were significantly decreased (P<0.01), as well as the HADS-depression subscale (HADS-D) and HADS-anxiety subscale (HADS) scores (P<0.05), while only the VAS score for abdominal pain in the control group was reduced (P<0.05), and the improvements of the scores in the observation group were more significant than those in the control group (P<0.05). After treatment, the serum CRP concentrations in both groups and the IL-12/IL-23 p40 concentration in the observation group were significantly decreased (P<0.05), and the concentrations in the observation group were lower than those in the control group (P<0.05). The expression levels of VDR protein and mRNA in the colon in both groups were all increased (P<0.01), and the expression levels of Reg IV protein and mRNA and CYP27B1 mRNA were all decreased in the two groups (P<0.05 or P<0.01); the improvements in the observation group were more notable than those in the control group (P<0.05 or P<0.01).ConclusionHerbal cake-partitioned moxibustion can effectively alleviate abdominal pain and diarrhea in patients with UC, improve depression and anxiety disorders, and regulate the expression of related proteins in the VDR signaling pathway. The mechanism may be related to inhibiting intestinal inflammation by reducing the release of the proinflammatory cytokine IL-12/IL-23 p40.

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.

Anti-Inflammatory Effects of 1,25(OH)2D/Calcitriol in T Cell Immunity: Does Sex Make a Difference?

Hypovitaminosis D is involved in various inflammatory, infectious and autoimmune diseases such as rheumatoid arthritis and multiple sclerosis. Moreover, the active form of vitamin D, calcitriol, has been shown to modulate the immune response, playing an anti-inflammatory effect. However little is known about the mechanisms underlying this anti-inflammatory effect and the potential sex differences of calcitriol immune regulation. Hence, the aim of this study was to investigate whether calcitriol could act differently in modulating T cell immunity of age-matched male and female healthy donors. We analyzed the effects of calcitriol in T lymphocytes from healthy women and men on the expression levels of the vitamin D receptor (VDR) and pro- and anti-inflammatory cytokine production. We showed that a treatment with calcitriol induced a significant increase in the VDR expression levels of activated T lymphocytes from male and female healthy subjects. Moreover, we found that calcitriol significantly reduced the expression level of pro-inflammatory cytokines IL-17, INF-γ and TNF-α in the T lymphocytes of both sexes. Notably, we observed that calcitriol induced a significant increase in the expression level of anti-inflammatory cytokine IL-10 only in the T lymphocytes from female healthy donors. In conclusion, our study provides new insights regarding the sex-specific anti-inflammatory role of calcitriol in T cell immunity.

Reduced vitamin D receptor (VDR) and cathelicidin antimicrobial peptide (CAMP) gene expression contribute to the maintenance of inflammatory immune response in leprosy patients

Leprosy is an infectious disease influenced by genetic, immunological, and environmental factors. Reduced gene expressions may be associated with the immunological response pattern and leprosy susceptibility. We investigated the direct and indirect effects of Vitamin D Receptor (VDR) and Cathelicidin Antimicrobial Peptide (CAMP) gene expressions on the serum levels of vitamin D, Cathelicidin, and cytokines in newly-diagnosed leprosy patients and post-six-months of multidrug therapy (MDT). Thirty-four leprosy patients were assessed, paucibacillary (PB; n = 14) and multibacillary (MB; n = 20) cases, untreated or having received six months of MDT, 18 healthy controls, and 25 household contacts. VDR and CAMP gene expression levels were strongly correlated to some important cytokines in both, untreated leprosy patients (PB, r = 0.9319; MB, r = 0.9569) and patients who had undergone MDT (PB, r = 0.9667; MB, r = 0.9569). We observed that both gene expressions directly influenced IL-2, IFN-γ, and IL-17F serum levels in leprosy patients compared to the household contacts and healthy individuals. VDR and CAMP gene expressions induced a persistent inflammatory response in PB and MB leprosy patients, even after six months of MDT, to fight the Mycobacterium leprae infection. Due to the persistent inflammatory profile, multidrug therapy is suggested to be maintained for more than six months, especially for MB patients. Vitamin D supplementation is recommended from the onset as a transcription factor to improve VDR and CAMP gene expression in leprosy patients.

VDR promotes nucleus pulposus cell mitophagy as a protective mechanism against oxidative stress injury

Intervertebral disk degeneration (IDD) is a common aging disease. Excessive apoptosis of nucleus pulposus (NP) cells has been widely considered a main contributor to IDD. Emerging science has shown that autophagy plays a protective role against apoptosis under oxidative stress. Vitamin D receptor (VDR) is a steroid hormone receptor that can regulate autophagy. The purpose of this study was to clarify whether VDR alleviates IDD by promoting autophagy. H2O2 stimulation was used to establish oxidative stress conditions. Initially, the expression level of VDR in human degenerative NP tissues was measured by immunohistochemistry. In addition, the CRISPR-dCas9-VPR system and siRNA were utilized to upregulate or downregulate VDR and Parkin expression, respectively. Autophagic and apoptotic markers were determined by Western blotting and RT–qPCR. Transmission electron microscopy was used to monitor the occurrence of autophagy in rat NP cells. VDR expression was downregulated in human degenerative NP tissues and H2O2-stimulated rat NP cells, indicating a negative correlation between VDR expression and IDD. VDR overexpression promoted mitophagy and prevented apoptosis and mitochondrial injury under oxidative stress. Additionally, mitophagy inhibition by 3-MA abolished the protective effect of VDR activation in vitro. Furthermore, VDR activation promoted mitophagy via the PINK1/Parkin pathway in H2O2-treated NP cells. This study demonstrates that VDR activation ameliorates oxidative damage and decreases NP cell apoptosis by promoting PINK1/Parkin-dependent mitophagy, indicating that VDR may serve as a promising therapeutic target in the management of IDD.

EB1089 promotes the expression of vitamin D receptor in the intestinal epithelial cell line HT-29 and reduces lipopolysaccharide-induced inflammatory response.

BackgroundEB1089 is a vitamin D receptor (VDR) agonist that reduces the inflammatory response. The specific pathway through which the inflammatory response is reduced is unclear, and this study is intended to investigate its effect on the inflammatory response through an LPS (lipopolysaccharide)-induced inflammation model of the intestinal epithelial cell line HT-29.MethodsWe divided HT-29 cells into a control group, LPS group, and LPS + EB1089 group. Cell proliferation was detected with a Cell Counting Kit-8 (CCK-8) kit, and the apoptosis rate was determined through flow cytometry, the lactate dehydrogenase (LDH), interleukin-18 (IL-18), and interleukin-1β (IL-1β) contents were measured with enzyme-linked immunosorbent assay (ELISA), and the expression levels of ASC, Caspase-1, NLRP3, VDR, TLR4, MYD88, NF-κB and other proteins in the cells were detected by western blot.ResultsPretreatment with EB1089 pretreatment reduced the LPS-induced apoptosis of HT-29 cells. LDH content was evidently lower in the LPS + EB1089 group than in the LPS group. The LDH content in the LPS + EB1089 group was evidently lower than that in the LPS group. The protein expression levels of ASC, Caspase-1, NLRP3, TLR4, MyD88, and NF-κB in the LPS group were evidently increased compared with those in the control group; however, the protein expression of VDR evidently decreased. The protein expression levels of Caspase-1, NLRP3, TLR4, MyD88, and NF-κB in the LPS + EB1089 group were evidently lower than those in the LPS group; however, the VDR protein expression evidently increased in the LPS + EB1089 group.ConclusionsEB1089 promoted the VDR expression and reduced the LPS induced inflammation in HT-29 cells.

The Expression of Inflammasomes NLRP1 and NLRP3, Toll-Like Receptors, and Vitamin D Receptor in Synovial Fibroblasts From Patients With Different Types of Knee Arthritis.

Activated rheumatoid arthritis (RA) synovial fibroblasts (SFs) are among the most important cells promoting RA pathogenesis. They are considered active contributors to the initiation, progression, and perpetuation of the disease; therefore, early detection of RASF activation could advance contemporary diagnosis and adequate treatment of undifferentiated early inflammatory arthritis (EA). In this study, we investigated the expression of nucleotide-binding, oligomerization domain (NOD)-like receptor family, pyrin domain containing (NLRP)1, NLRP3 inflammasomes, Toll-like receptor (TLR)1, TLR2, TLR4, vitamin D receptor (VDR), and secretion of matrix metalloproteinases (MMPs) in SFs isolated from patients with RA, osteoarthritis (OA), EA, and control individuals (CN) after knee surgical intervention. C-reactive protein, general blood test, anticyclic citrullinated peptide (anti-CCP), rheumatoid factor (RF), and vitamin D (vitD) in patients’ sera were performed. Cells were stimulated or not with 100 ng/ml tumor necrosis factor alpha (TNF-α) or/and 1 nM or/and 0.01 nM vitamin D3 for 72 h. The expression levels of NLRP1, NLRP3, TLR1, TLR2, TLR4, and VDR in all examined SFs were analyzed by quantitative real-time PCR (RT-qPCR). Additionally, the secretion of IL-1β by SFs and MMPs were determined by ELISA and Luminex technology. The expression of NLRP3 was correlated with the levels of CRP, RF, and anti-CCP, suggesting its implication in SF inflammatory activation. In the TNF-α-stimulated SFs, a significantly lower expression of NLRP3 and TLR4 was observed in the RA group, compared with the other tested forms of arthritis. Moreover, upregulation of NLRP3 expression by TNF-α alone or in combination with vitD3 was observed, further indicating involvement of NLRP3 in the inflammatory responses of SFs. Secretion of IL-1β was not detected in any sample, while TNF-α upregulated the levels of secreted MMP-1, MMP-7, MMP-8, MMP-12, and MMP-13 in all patient groups. Attenuating effects of vitD on the expression of NLRP3, TLR1, and TLR4 suggest potential protective effects of vitD on the inflammatory responses in SFs. However, longer studies may be needed to confirm or fully rule out the potential implication of vitD in SF activation in inflammatory arthritis. Both VDR and NLRP3 in the TNF-α-stimulated SFs negatively correlated with the age of patients, suggesting potential age-related changes in the local inflammatory responses.