RNAi-mediated knockdown of VDR surprisingly suppresses cell growth in Jurkat T and U87-MG cells

Loss of the vitamin D receptor triggers senescence in chronic myeloid leukemia via DDIT4-mediated DNA damage

Chronic myeloid leukemia (CML) is a hematopoietic malignancy driven by the fusion gene BCR::ABL1. Drug resistance to tyrosine kinase inhibitors (TKIs), due to BCR::ABL1 mutations and residual leukemia stem cells (LSCs), remains a major challenge in CML treatment. Here, we revealed the requirement of the vitamin D receptor (VDR) in the progression of CML. VDR was upregulated by BCR::ABL1 and highly expressed in CML cells. Interestingly, VDR knockdown inhibited the proliferation of CML cells driven by both BCR::ABL1 and TKI-resistant BCR::ABL1 mutations. Mechanistically, VDR transcriptionally regulated DDIT4 expression; reduced DDIT4 levels upon VDR knockdown triggered DNA damage and senescence via p53 signaling activation in CML cells. Furthermore, VDR deficiency not only suppressed tumor burden and progression in primary CML mice but also reduced the self-renewal capacity of CML-LSCs. Together, our study demonstrated that targeting VDR is a promising strategy to overcome TKI resistance and eradicate LSCs in CML.

Relationship between Maternal Vitamin D Levels and Adverse Outcomes

Vitamin D (VD), a fat-soluble vitamin, has a variety of functions that are important for growth and development, including regulation of cell differentiation and apoptosis, immune system development, and brain development. As such, VD status during pregnancy is critical for maternal health, fetal skeletal growth, and optimal pregnancy outcomes. Studies have confirmed that adverse pregnancy outcomes, such as preeclampsia, low birth weight, neonatal hypocalcemia, poor postnatal growth, skeletal fragility, and increased incidence of autoimmune diseases, can be associated with low VD levels during pregnancy and infancy. Thus, there is growing interest in the role of VD during pregnancy. This review summarizes the potential adverse health outcomes of maternal VD status during pregnancy for both mother and offspring (gestational diabetes mellitus, hypertensive gestational hypertension, intrauterine growth restriction, miscarriage, stillbirth, and preterm birth) and discusses the underlying mechanisms (regulation of cytokine pathways, immune system processing, internal secretion, placental function, etc.) of VD in regulating each of the outcomes. This review aims to provide a basis for public health intervention strategies to reduce the incidence of adverse pregnancies.

Vitamin D receptor expression in SLE peripheral blood CD4+T cells is associated with disease activity and cell apoptosis

OBJECTIVES

Systemic lupus erythematosus (SLE) is characterised by accumulated cell apoptosis. Vitamin D receptor (VDR) has immunomodulatory effect and potent anti-apoptosis activities. The aim of this study was to examine the correlation between CD4+T cells VDR expression, cell apoptosis, and disease activity in patients with SLE.

METHODS

Forty-five SLE patients were recruited and 50 healthy individuals served as controls. The expression of VDR in CD4+T cells and their subsets were determined by flow cytometry. The correlations between VDR expression and cell apoptosis or disease parameters in SLE patients were analysed.

RESULTS

VDR expression in CD4+T cells and their subsets were upregulated in SLE patients, especially in help T (Th)1, regulatory T (Treg), and follicular helper T (Tfh) cells. Frequency of VDR-positive CD4+T cells was positively associated with SLE disease activity index (SLEDAI)-2K values and inversely correlated with serum C3 concentration. The frequency of VDR-positive CD4+T cells, Th1 cells, Th2 cells, Th17 cells, Treg cells, and Tfh cells was positively correlated with cells apoptosis.

CONCLUSION

VDR expression in CD4+T cells and their subsets were increased in SLE. VDR expression was positively associated with disease activity and cell apoptosis in SLE patients.

Vitamin D changes expression of DNA repair genes in the patients with multiple sclerosis

Oxidative stress (OS) plays an essential role in demyelination and tissue injury related to pathogenesis of multiple sclerosis (MS). On the other hand, vitamin D (VD) as an antioxidant reduces oxidative stress and has been used as adjuvant therapy in autoimmune diseases. Although VD supplementation is suggested as a protective and immunomodulation factor for MS patients, the molecular mechanisms remain unclear. Given that VD may modulate the immune system of MS patients through the DNA repair pathway, we aimed to evaluate the effects of VD supplementation in DNA repair genes expression including OGG1, MYH, MTH1, and ITPA. Transcript levels were measured using the RT-qPCR method in peripheral blood mononuclear cells (PBMCs) of relapsing-remitting multiple sclerosis (RRMS) patients before and after two months of VD supplementation. Furthermore, in silico analysis and correlation gene expression analysis was performed to find the biological binding sites and the effect of NRF2 on the regulation of DNA repair genes. Our data revealed that in MS patients, 2-month VD treatment significantly altered the expression of MYH, OGG1, MTH1, and NRF2 genes. A significant correlation was observed between DNA repair genes and NRF2 expression, which was confirmed by the presence of antioxidant response element (ARE) binding sites in the promoter of OGG1, MYH, and MTH1 genes. This study demonstrated that the impact of VD on MS patients may be mediated through the improvement of DNA repair system efficiency. This finding brought some new evidence for the involvement of DNA repair genes in the physiopathology of MS patients.