Vitamin D receptor protects glioblastoma A172 cells against Coxsackievirus A16 infection induced cell death in the pathogenesis of hand, foot, and mouth disease

Vitamin D receptor gene methylation in patients with hand, foot, and mouth disease caused by enterovirus 71

To evaluate the epigenetic regulation of the VDR gene in enterovirus 71 (EV71)-associated severe hand, foot, and mouth disease (HFMD), a total of 116 patients with EV71-HFMD, including 58 with mild EV71-HFMD and 58 with severe EV71-HFMD, as well as 60 healthy controls, were enrolled in this study. Quantitative real-time PCR was used to measure the relative levels of VDR mRNA expression, and the methylation status of the VDR promoter was assessed using a MethylTarget™ assay. The DNA methylation levels of the VDR promoter in children with EV71-associated severe HFMD were lower than those in the healthy controls and in children with mild HFMD (P < 0.05). Hypomethylation at CpG site 133 and hypermethylation at the CpG 42 sites and 68 downregulated VDR expression. Moreover, the methylation level of VDR could be used for differential diagnosis of mild and severe EV71-associated HFMD (AUC₅₆, 0.73; AUC₆₈, 0.699; AUC₄₂, 0.694; AUC₆₆, 0.693). VDR expression and promoter methylation were associated with the progression of EV71 infection. Determining the VDR promoter status might help clinicians initiate the appropriate strategy for treatment of EV71-associated HFMD.

Association of polymorphisms in the vitamin D receptor gene with susceptibility to and severity of hand, foot, and mouth disease caused by coxsackievirus A16

Coxsackievirus A16 (CA16) remains the most common causative agent of hand, foot, and mouth disease (HFMD), and is related to high incidence and critical complications. Vitamin D receptor (VDR) activity might affect the outcome of CA16 infection. Our case-control research aims to evaluate the relationship between VDR polymorphisms in the gene encoding and susceptibility to and severity of HFMD due to CA16. Three single-nucleotide polymorphisms (SNPs) of VDR gene were selected according to functional prediction and linkage disequilibrium, and were examined utilizing the SNPscan method to identify possible associations with HFMD caused by CA16. A significant relationship was found in the HFMD cases of polymorphism rs11574129 (GA vs GG: odds ratio (OR) = 0.068, 95% confidence interval (CI) = 0.007-0.693, P = .023; GA + AA vs GG: OR = 0.322, 95%CI = 0.106-0.984, P = .047), and vitamin D levels in genotype AA were significantly higher than those in genotype GG (P < .05). These results suggest that VDR rs11574129 may influence genetic susceptibility to CA16-associated HFMD.

The interplay between vitamin D and viral infections

The pleiotropic role of vitamin D has been explored over the past decades and there is compelling evidence for an epidemiological association between poor vitamin D status and a variety of diseases. While the potential anti-viral effect of vitamin D has recently been described, the underlying mechanisms by which vitamin D deficiency could contribute to viral disease development remain poorly understood. The possible interactions between viral infections and vitamin D appear to be more complex than previously thought. Recent findings indicate a complex interplay between viral infections and vitamin D, including the induction of anti-viral state, functional immunoregulatory features, interaction with cellular and viral factors, induction of autophagy and apoptosis, and genetic and epigenetic alterations. While crosstalk between vitamin D and intracellular signalling pathways may provide an essential modulatory effect on viral gene transcription, the immunomodulatory effect of vitamin D on viral infections appears to be transient. The interplay between viral infections and vitamin D remains an intriguing concept, and the global imprint that vitamin D can have on the immune signature in the context of viral infections is an area of growing interest.

Association of polymorphisms in the vitamin D receptor gene with severity of hand, foot, and mouth disease caused by enterovirus 71

Severe hand, foot, and mouth disease (HFMD) is sometimes associated with critical complications that can cause substantial child mortality. Activity of the vitamin D receptor (VDR) may influence the outcomes of enterovirus 71 (EV71) infection. This case-control study aimed to assess the association of single-nucleotide polymorphisms (SNPs) in the gene encoding the VDR with the severity of EV71-associated HFMD. We selected four VDR SNPs based on linkage disequilibrium and functional prediction, and we tested them using the SNPscan multiple SNP typing method for potential association with severity of EV71-associated HFMD. We found a significant association in the case of rs11574129 (G vs A: odds ratio (OR), 0.3439; 95% confidence intervals (CI), 0.1778-0.6653) and rs739837 (T vs G: OR, 0.5580; 95%CI, 0.3352-0.9291). Our results suggest that these two SNPs may influence the severity of EV71-associated HFMD.

Vitamin D status, enterovirus infection, and type 1 diabetes in Italian children/adolescents

At the time of the clinical onset of type 1 diabetes (T1D), we investigated 82 pediatric cases in parallel with 117 non-diabetic controls matched by age, geographic area, and time of collection. The occurrence of an enteroviral infection was evaluated in peripheral blood using a sensitive method capable of detecting virtually all human enterovirus (EV) types. While non-diabetic controls were consistently EV-negative, 65% of T1D cases carried EVs in blood. The vitamin D status was assessed by measuring the concentration of 25-hydroxyvitamin D [25(OH)D] in serum. Levels of 25(OH)D were interpreted as deficiency (≤50 nmol/L), insufficiency (52.5-72.5 nmol/L), and sufficiency (75-250 nmol/L). In T1D cases, the median serum concentration of 25(OH)D was 54.4 ± 27.3 nmol/L vs 74.1 ± 28.5 nmol/L in controls (P = .0001). Diabetic children/adolescents showed deficient levels of vitamin D 25(OH)D (ie, 72.5 nmol/L) in 48.8% cases vs 17.9% in non-diabetic controls (P = .0001). Unexpectedly, the median vitamin D concentration was significantly reduced in virus-positive vs virus-negative diabetics (48.2 ± 22.5 vs 61.8 ± 31.2 nmol/L; P = .015), with deficient levels in 58.5% vs 31.0%, respectively. Thus, at the time of clinical onset, EV-positive cases had reduced vitamin D levels compared with EV-negative cases. This could indicate either that the virus-negative children/adolescents had been hit by a non-infectious T1D-triggering event, or that children/adolescents with proper levels of vitamin D had been able to rapidly clear the virus. Thus, it would be important to assess whether adequate vitamin D supplementation before or during the prediabetic phase of T1D may counteract the diabetogenic potential of infectious pathogens.