Human cytomegalovirus infection downregulates vitamin-D receptor in mammalian cells

Significance of vitamin D responsiveness on the etiology of vitamin D-related diseases

Vitamin D resistance (VDRES) explains the necessity for higher doses of Vitamin D (VD) than those recommended for treatment success. VD receptor (VDR) signaling blockade, such as that caused by infections and poisons, is one basis for VDRES etiology. Mutations within genes affecting the VD system cause susceptibility to developing low VD responsiveness and autoimmunity. In contrast, VD hypersensitivity (VDHY) occurs if there is extra VD in the body; for example, as a result of an overdose of a VD supplement. Excess 1,25(OH)2D3 is produced in lymphomas and granulomatous diseases. The placenta produces excess 1,25(OH)2D3. Gene mutations regulating the production or degradation of 1,25(OH)2D3 enhance the effects of 1,25(OH)2D3. Increased 1,25(OH)2D3 levels stimulate calcium absorption in the gut, leading to hypercalcemia. Hypercalcemia can result in the calcification of the kidneys, circulatory system, or placenta, leading to kidney failure, cardiovascular disease, and pregnancy complications. The primary treatment involves avoiding exposure to the sun and VD supplements. The prevalence rates of VDRES and VDHY remain unclear. One estimate was that 25%, 51%, and 24% of the patients had strong, medium, and poor responses, respectively. Heavy-dose VD therapy may be a promising method for the treatment of autoimmune diseases; however, assessing its potential side effects is essential. To avoid VD-mediated hypercalcemia, responsiveness must be considered when treating pregnancies or cardiovascular diseases associated with VD. Furthermore, how VD is associated with the related disorders remains unclear. Investigating responsiveness to VD may provide more accurate results.

Zika virus infection suppresses CYP24A1 and CAMP expression in human monocytes

Monocytes are the primary targets of Zika virus (ZIKV) and are associated with ZIKV pathogenesis. Currently, there is no effective treatment for ZIKV infection. It is known that 1,25-dihydroxy vitamin D3 (VitD3) has strong antiviral activity in dengue virus-infected macrophages, but it is unknown whether VitD3 inhibits ZIKV infection in monocytes. We investigated the relationship between ZIKV infection and the expression of genes of the VitD3 pathway, as well as the inflammatory response of infected monocytes in vitro. ZIKV replication was evaluated using a plaque assay, and VitD3 pathway gene expression was analyzed by RT-qPCR. Pro-inflammatory cytokines/chemokines were quantified using ELISA. We found that VitD3 did not suppress ZIKV replication. The results showed a significant decrease in the expression of vitamin D3 receptor (VDR), cytochrome P450 family 24 subfamily A member 1 (CYP24A1), and cathelicidin antimicrobial peptide (CAMP) genes upon ZIKV infection. Treatment with VitD3 was unable to down-modulate production of pro-inflammatory cytokines, except TNF-α, and chemokines. This suggests that ZIKV infection inhibits the expression of VitD3 pathway genes, thereby preventing VitD3-dependent inhibition of viral replication and the inflammatory response. This is the first study to examine the effects of VitD3 in the context of ZIKV infection, and it has important implications for the role of VitD3 in the control of viral replication and inflammatory responses during monocyte infection.

Therapeutic high-dose vitamin D for vitamin D-deficient severe COVID-19 disease: randomized, double-blind, placebo-controlled study (SHADE-S)

BACKGROUND

efficacy of therapeutic cholecalciferol supplementation for severe COVID-19 is sparingly studied.

OBJECTIVE

effect of single high-dose cholecalciferol supplementation on sequential organ failure assessment (SOFA) score in moderate-to-severe COVID-19.

METHODS

participants with moderate to severe COVID-19 with PaO2/FiO2 ratio < 200 were randomized to 0.6 million IU cholecalciferol oral (intervention) or placebo.

OUTCOMES

primary outcome was change in Day 7 SOFA score and pre-specified secondary outcomes were SOFA and 28-day all-cause mortality.

RESULTS

in all, 90 patients (45 each group) were included for intention-to-treat analysis. 25(OH)D3 levels were 12 (10-16) and 13 (12-18) ng/ml (P = 0.06) at baseline; and 60 (55-65) ng/ml and 4 (1-7) ng/ml by Day 7 in vitamin D and placebo groups, respectively. The SOFA score on Day 7 was better in the vitamin D group [3 (95% CI, 2-5) versus 5 (95% CI, 3-7), P = 0.01, intergroup difference - 2 (95% CI, -4 to -0.01); r = 0.4]. A lower all-cause 28-day mortality [24% compared to 44% (P = 0.046)] was observed with vitamin D.

CONCLUSIONS

single high-dose oral cholecalciferol supplementation on ICU admission can improve SOFA score at Day 7 and reduce in-hospital mortality in vitamin D-deficient COVID-19. ClinicalTrials.gov  id: NCT04952857 registered dated 7 July 2021. What is already known on this topic-vitamin D has immunomodulatory role. Observational and isolated intervention studies show some benefit in COVID-19. Targeted therapeutic vitamin D supplementation improve outcomes in severe COVID-19 is not studied in RCTs. What this study adds-high-dose vitamin D supplementation (0.6 Million IU) to increase 25(OH)D > 50 ng/ml is safe and reduces sequential organ failure assessment score, in-hospital mortality in moderate to severe COVID-19. How this study might affect research, practice or policy-vitamin D supplementation in vitamin D-deficient patients with severe COVID-19 is useful may be practiced.

The Distinct Regulation of the Vitamin D and Aryl Hydrocarbon Receptors in COVID-19

(1) Background: SARS-CoV-2 affects several immune pathways, including the vitamin D (VDR) and the aryl hydrocarbon receptor pathways (AhR). The aim of the study was the evaluation of the VDR and AhR pathways in the blood of COVID-19 patients with regard to the severity of disease. (2) Methods: Observational, single-center, case-control design. A total of 240 samples were selected for exploration. Patients who tested negative for SARS-CoV-2 but suffered from other respiratory infections (ORIs) served as a control group. (3) Results: VDR-specific mRNA in the blood of patients with mild symptoms (131.2 ± 198.6) was significantly upregulated relative to the VDR expression of the ORI group (23.24 ± 42.60; p < 0.0001); however, VDR expression of critically ill patients showed an impaired upregulation (54.73 ± 68.34; p < 0.001). CYP27B1 expression was not significantly regulated during SARS-CoV-2 infection. There was a downregulation of VDR and CYP27B1 compared to survivors. There was no significant difference in 25(OH)-vitamin D3 levels between critically ill patients with regard to survival (24.3 ± 9.4 vs. 27.1 ± 11.3; p = 0.433). (4) Conclusion: The VDR and AhR pathways are distinctively regulated in patients suffering from COVID-19 depending on the severity of disease. A combination treatment of antiviral drugs and vitamin D substitution should be evaluated for potentially improved prognosis in COVID-19.

Piscine Vitamin D Receptors Vdra/Vdrb in the Absence of Vitamin D Are Utilized by Grass Carp Reovirus for Promoting Viral Replication

The vitamin D receptor (VDR) plays a pivotal role in the biological actions of vitamin D (VitD). However, little is known about the functions of VDR in the production of viral inclusion bodies (VIBs). Using a representative strain of grass carp reovirus (GCRV) genotype I, GCRV-873, we show that GCRV-873 recruits grass carp Vdrs for promoting the production of VIBs in the absence of VitD. Inhibition of cholesterol synthesis by lovastatin impairs the production of VIBs and blocks the effects of grass carp Vdrs in promoting the production of VIBs in the absence of VitD. Furthermore, grass carp Vdrs are found to form the Vdra-Vdrb heterodimer, which is vital for 3-hydroxy-3-methylglutaryl-coenzyme A reductase (hmgcr)-dependent cholesterol synthesis and GCRV replication. Intriguingly in the presence of VitD, grass carp Vdra but not Vdrb forms the heterodimer with the retinoid X receptor beta b (Rxrbb), which induces the transcription of those genes involved in the RIG-I-like receptor (RLR) antiviral signaling pathway for inhibiting GCRV infection. Furthermore, the VitD-activated Vdra-Vdrb heterodimer attenuates the transcription of the RLR antiviral signaling pathway induced by VitD. In the presence of VitD, a balance between the Vdra-Rxrbb heterodimers as coactivators and Vdra-Vdrb heterodimers as corepressors in affecting the transcriptional regulation of the RLR antiviral signaling pathway may eventually determine the outcome of GCRV infection. Transfection with VitD can abolish the effect of grass carp Vdrs in promoting GCRV replication in a dose-dependent manner. Taken together, these findings demonstrate that GCRV utilizes host Vdrs to increase hmgcr-dependent cholesterol synthesis for promoting its replication, which can be prevented by VitD treatment. IMPORTANCE Grass carp reovirus (GCRV) is the causative agent of grass carp hemorrhagic disease, which seriously harms freshwater fish. Although many positive or negative regulators of GCRV infection have been identified in teleosts, little is known about the molecular mechanisms by which GCRV utilizes host factors to generate its infectious compartments beneficial for viral replication and infection. Here, we show that in the absence of VitD, the GCRV-873 strain utilizes host vitamin D receptors Vdra/Vdrb to increase hmgcr-dependent cholesterol synthesis for promoting the production of VIBs, which are important functional sites for aquareovirus replication and assembly. The negative regulation of Vdrs during viral infection can be prevented by VitD treatment. Thus, this present work broadens understanding of the pivotal roles of Vdrs in the interaction between the host and GCRV in the absence or presence of VitD, which might provide a rational basis for developing novel anti-GCRV strategies.

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: A Role Also in Long COVID-19?

Coronavirus disease 2019 (COVID-19) has quickly become a global pandemic. Reports from different parts of the world indicate that a significant proportion of people who have recovered from COVID-19 are suffering from various health problems collectively referred to as “long COVID-19”. Common symptoms include fatigue, shortness of breath, cough, joint pain, chest pain, muscle aches, headaches, and so on. Vitamin D is an immunomodulatory hormone with proven efficacy against various upper respiratory tract infections. Vitamin D can inhibit hyperinflammatory reactions and accelerate the healing process in the affected areas, especially in lung tissue. Moreover, vitamin D deficiency has been associated with the severity and mortality of COVID-19 cases, with a high prevalence of hypovitaminosis D found in patients with COVID-19 and acute respiratory failure. Thus, there are promising reasons to promote research into the effects of vitamin D supplementation in COVID-19 patients. However, no studies to date have found that vitamin D affects post-COVID-19 symptoms or biomarkers. Based on this scenario, this review aims to provide an up-to-date overview of the potential role of vitamin D in long COVID-19 and of the current literature on this topic.

Cytomegalovirus Infection Downregulates Vitamin D Receptor in Patients Undergoing Hematopoietic Stem Cell Transplantation

BACKGROUND

Allogeneic hematopoietic stem cell transplantation (HSCT) is a potentially curative option for patients with hematologic diseases but is associated with high mortality and morbidity. Cytomegalovirus (CMV) infection is common in HSCT patients and modulates vitamin D metabolism in vitro. We aimed at validating CMV-associated vitamin D metabolism in vivo in HSCT.

METHODS

Patients treated for significant CMV viremia after HSCT were evaluated for CMV load before, during, and after antiviral treatment. RNA was isolated from whole-blood samples to test for regulation of key components of the vitamin D receptor (VDR) pathway during different phases of CMV viremia.

RESULTS

CMV viremia developed a mean time of 102 (±34) d post-HSCT. Maximum levels of CMV-DNA reached a mean of 5668 (±7257) copies/mL. VDR expression was downregulated to a mean of 64.3% (±42.5%) relative to the VDR expression pre-CMV viremia (P = 0.035) and lagged in recovery following antiviral treatment. Toll-like receptor (TLR) 2 mRNA was upregulated to 225.4% during CMV viremia relative to the expression pre-CMV viremia (P = 0.012) but not TLR6/7/8 and the TLR-adaptor protein MyD88. Levels of 25-OH vitamin D were reduced in all viremic patients (48.0 ± 4.8 versus 25.1 ± 3.7 ng/mL) and were even lower after periods of CMV viremia compared with the control group (48.3 ± 3.5 versus 17.8 ± 1.8 ng/mL; P = 0.008).

CONCLUSIONS

CMV viremia is associated with significant dysregulation of vitamin D metabolism in HSCT patients.

Protein Phosphatase 1 Regulates Human Cytomegalovirus Protein Translation by Restraining AMPK Signaling

Human cytomegalovirus (HCMV) carries the human protein phosphatase 1 (PP1) and other human proteins important for protein translation in its tegument layer for a rapid supply upon infection. However, the biological relevance behind PP1 incorporation and its role during infection is unclear. Additionally, PP1 is a difficult molecular target due to its promiscuity and similarities between the catalytic domain of multiple phosphatases. In this study, we circumvented these shortcomings by using 1E7-03, a small molecule protein–protein interaction inhibitor, as a molecular tool of noncatalytic PP1 inhibition. 1E7-03 treatment of human fibroblasts severely impaired HCMV replication and viral protein translation. More specifically, PP1 inhibition led to the deregulation of metabolic signaling pathways starting at very early time points post-infection. This effect was at least partly mediated by the prevention of AMP-activated protein kinase dephosphorylation, leading to elongation factor 2 hyperphosphorylation and reduced translation rates. These findings reveal an important mechanism of PP1 for lytic HCMV infection.

Vitamin D Resistance as a Possible Cause of Autoimmune Diseases: A Hypothesis Confirmed by a Therapeutic High-Dose Vitamin D Protocol

Vitamin D3 (cholecalciferol) is a secosteroid and prohormone which is metabolized in various tissues to the biologically most active vitamin D hormone 1,25(OH)2D3 (calcitriol). 1,25(OH)2D3 has multiple pleiotropic effects, particularly within the immune system, and is increasingly utilized not only within prophylaxis, but also within therapy of various diseases. In this context, the latest research has revealed clinical benefits of high dose vitamin D3 therapy in autoimmune diseases. The necessity of high doses of vitamin D3 for treatment success can be explained by the concept of an acquired form of vitamin D resistance. Its etiology is based on the one hand on polymorphisms within genes affecting the vitamin D system, causing susceptibility towards developing low vitamin D responsiveness and autoimmune diseases; on the other hand it is based on a blockade of vitamin D receptor signaling, e.g. through pathogen infections. In this paper, we review observational and mechanistic evidence for the acquired vitamin D resistance hypothesis. We particularly focus on its clinical confirmation from our experience of treating multiple sclerosis patients with the so-called Coimbra protocol, in which daily doses up to 1000 I.U. vitamin D3 per kg body weight can be administered safely. Parathyroid hormone levels in serum thereby provide the key information for finding the right dose. We argue that acquired vitamin D resistance provides a plausible pathomechanism for the development of autoimmune diseases, which could be treated using high-dose vitamin D3 therapy.

Hidden in plain sight: The effects of BCG vaccination in the COVID-19 pandemic

To investigate the relationship between Bacille Calmette‐Guérin (BCG) vaccination and SARS‐CoV‐2 by a bioinformatics approach, two datasets for the SARS‐CoV‐2 infection group and BCG‐vaccinated group were downloaded. Differentially Expressed Genes were identified. Gene ontology and pathways were functionally enriched, and networking was constructed in NetworkAnalyst. Lastly, the correlation between post‐BCG vaccination and COVID‐19 transcriptome signatures was established. A total of 161 DEGs (113 upregulated DEGs and 48 downregulated genes) were identified in the SARS‐CoV‐2 group. In the pathway enrichment analysis, a cross‐reference of upregulated Kyoto Encyclopedia of Genes and Genomes pathways in SARS‐CoV‐2 with downregulated counterparts in the BCG‐vaccinated group, resulted in the intersection of 45 common pathways, accounting for 86.5% of SARS‐CoV‐2 upregulated pathways. Of these intersecting pathways, a vast majority were immune and inflammatory pathways with top significance in interleukin‐17, tumor necrosis factor, NOD‐like receptors, and nuclear factor‐κB signaling pathways. Given the inverse relationship of the specific differentially expressed gene pathways highlighted in our results, the BCG‐vaccine may play a protective role against COVID‐19 by mounting a nonspecific immunological response and further investigation of this relationship is warranted.

Insights Into the Role of Vitamin D as a Biomarker in Stem Cell Transplantation

Vitamin D was discovered 100 years ago and since then multiple studies have consistently proved its effect on bone health and mineral metabolism. Further research has also explored its so-called "non-classical" biological effects, encompassing immune regulation and control of cell proliferation and differentiation. Vitamin D downregulates pro-inflammatory immune cells and subsequently their cytokine production, while enhancing the anti-inflammatory subsets, thus mediating inflammation and fostering a more tolerogenic environment. Its biological action is exerted through the vitamin D receptor, a nuclear receptor that mediates gene transcription and is expressed in most cells from the innate and adaptive immunity. Owing to its immune-modulatory properties, its role in cancer pathophysiology, hematology disorders and stem cell transplantation has also been investigated. Vitamin D deficiency causes immune imbalance and cytokine dysregulation, contributing to some autoimmune diseases. In the hematopoietic stem cell transplant setting this could lead to complications such as acute and chronic graft-versus-host disease, ultimately impacting transplant outcomes. Other factors have also been linked to this, including specific polymorphisms of the vitamin D receptor in both stem cell donors and recipients. Nevertheless, studies thus far have shown conflicting results and the use of vitamin D or its receptor as biomarkers has not been validated yet, therefore there are no evidence-based consensus guidelines to guide clinicians in their day-to-day practice. To gain more insight in this topic, we have reviewed the existent literature and gathered the current evidence. This is an overview of the role of serum vitamin D and its receptor as biomarkers for clinical outcomes in patients undergoing hematopoietic stem cell transplantation. Further prospective studies with larger cohorts are warranted to validate the viability of using serum vitamin D, and its receptor, as biomarkers in potential stem cell donors and patients, to identify those at risk of post-transplant complications and enable early therapeutic interventions.

Controversial Effects of Vitamin D and Related Genes on Viral Infections, Pathogenesis, and Treatment Outcomes

Vitamin D (VD) plays an essential role in mineral homeostasis and bone remodeling. A number of different VD-related genes (VDRG) are required for the metabolic activation of VD and the subsequent induction of its target genes. They include a set of genes that encode for VD-binding protein, metabolic enzymes, and the VD receptor. In addition to its well-characterized skeletal function, the immunoregulatory activities of VD and the related polymorphisms of VDRG have been reported and linked to its therapeutic and preventive actions for the control of several viral diseases. However, in regards to their roles in the progression of viral diseases, inconsistent and, in some cases, contradictory results also exist. To resolve this discrepancy, I conducted an extensive literature search by using relevant keywords on the PubMed website. Based on the volume of hit papers related to a certain viral infection, I summarized and compared the effects of VD and VDRG polymorphism on the infection, pathogenesis, and treatment outcomes of clinically important viral diseases. They include viral hepatitis, respiratory viral infections, acquired immunodeficiency syndrome (AIDS), and other viral diseases, which are caused by herpesviruses, dengue virus, rotavirus, and human papillomavirus. This review will provide the most current information on the nutritional and clinical utilization of VD and VDRG in the management of the key viral diseases. This information should be valuable not only to nutritionists but also to clinicians who wish to provide evidence-based recommendations on the use of VD to virally infected patients.

Low maternal vitamin D is associated with increased risk of congenital and peri/postnatal transmission of Cytomegalovirus in women with HIV

Background

CMV infection of the fetus or neonate can lead to devastating disease, and there are no effective prevention strategies to date. Vitamin D is a potent immunomodulator, supports antiviral immune responses, and plays an important role in placental immunity.

Methods

Retrospective cohort study to evaluate the impact of low maternal vitamin D on congenital and early postnatal transmission of CMV among HIV-infected, non-breastfeeding women and their HIV exposed but negative infants from an urban HIV clinic. Vitamin D panel was performed on stored maternal plasma obtained near time of delivery. Infant CMV testing at 0–6 months included urine and oral cultures, and/or serum polymerase chain reaction testing.

Results

Cohort included 340 mother-infant pairs (births 1991–2014). Among 38 infants (11%) with a CMV+ test between 0–6 months, 4.7% (14/300) had congenital CMV transmission (CMV+ test 0–3 weeks), and 7.6% (24/315) had peri/postnatal CMV (CMV+ test >3 weeks-6 months). Women with lower calcitriol (1,25-dihydroxyvitamin D), the active form of vitamin D, were more likely to have an infant with congenital (OR 12.2 [95% CI 1.61–92.2] P = 0.02) and peri/postnatal (OR 9.84 [95% CI 2.63–36.8] P = 0.0007) infections in multivariate analyses, independent of maternal HIV viral load and CD4 count.

Conclusion

This study demonstrates an association between inadequate maternal calcitriol during pregnancy and increased congenital and early postnatal acquisition of CMV among non-breastfeeding women with HIV and their HIV negative infants.

Vitamin D: is it important in haematopoietic stem cell transplantation? A review

Vitamin D has effects on several body systems, from well-established role in bone metabolism to emerging effects on the immune system. Increasing evidence supports an immunomodulatory effect including inhibition of the pro-inflammatory lymphocyte subsets while enhancing their anti-inflammatory counterpart, in favour of a more tolerogenic status. Vitamin D deficiency is increasingly recognised in association with autoimmune and inflammatory diseases, also with evidence from the field of asthma where vitamin D supplementation may overcome steroid resistance. In the HSCT setting, vitamin D deficiency has been variably associated with increased complications, including graft-versus-host disease (GvHD), with a potential impact on survival outcomes. In this review we provide an overview and critical appraisal of the current literature of the role of vitamin D (and its deficiency) in relation to immunity in both allogeneic and autologous HSCT settings. We conclude that the evidence base is mixed, but a greater understanding of the role of vitamin D in relation to immune reconstitution following HSCT is warranted. Given its potential benefits, its inexpensive cost and favourable side effect profile, consideration of vitamin D levels and its supplementation could be easily incorporated into prospective studies in GvHD, including clinical trials of novel therapeutics, supportive care and biomarkers.

Vitamin D Compounds Are Bactericidal against Streptococcus mutans and Target the Bacitracin-Associated Efflux System

Vitamin D analogs were identified as compounds that induced lysis of planktonic cultures of Streptococcus mutans in a high-throughput screen of FDA-approved drugs. Previous studies have demonstrated that certain derivatives of vitamin D possess lytic activity against other bacteria, though the mechanism has not yet been established. Through the use of a combinatorial approach, the vitamin D derivative doxercalciferol was shown to act synergistically with bacitracin, a polypeptide-type drug that is known to interfere with cell wall synthesis, suggesting that doxercalciferol may act in a bacitracin-related pathway. Innate resistance to bacitracin is attributed to efflux by a conserved ABC-type transporter, which in S. mutans is encoded by the mbrABCD operon. S. mutans possesses two characterized mechanisms of resistance to bacitracin, the ABC transporter, S. mutans bacitracin resistance (Mbr) cassette, consisting of MbrABCD, and the rhamnose-glucose polysaccharide (Rgp) system, RgpABCDEFGHI. Loss of function of the transporter in ΔmbrA and ΔmbrD mutants exacerbated the effect of the combination of doxercalciferol and bacitracin. Despite conservation of a transporter homologous to mbrABCD, the combination of doxercalciferol and bacitracin appeared to be synergistic only in streptococcal species. We conclude that vitamin D derivatives possess lytic activity against S. mutans and act through a mechanism dependent on the bacitracin resistance mechanism of MbrABCD.