Vitamin D improves autoimmune diseases by inhibiting Wnt signaling pathway.

OBJECTIVE: In this study, we investigated the development of the Wnt signaling pathway in vitamin D (VitD) to improve systemic lupus erythematosus in mice to breakthrough clinical treatment approaches. METHODS: Body weight changes were recorded during rearing. Antinuclear antibodies (ANA), anti-dsDNA, and anti-snRNP were detected in the mouse serum using an enzyme-linked immunosorbent assay. Apoptosis of Th1 and Th2 immune cells in mice was detected using flow cytometry. Reverse transcription polymerase chain reaction was used to detect the expression of T-bet, GATA3, and Wnt3a mRNA in the spleens of each group. Western blot analysis was performed to detect the expression of Wnt1, p-ß-catenin, ß-catenin, glycogen synthase kinsase3ß (GSK-3ß), Wnt3a, c-myc, and cyclin D1 protein in mice spleens. ß-catenin in mice spleen was visualized using immunohistochemistry. RESULTS: VitD did not substantial reduce the body weight of MRL/LPR mice, whereas the inhibitor did. VitD notably decreased the concentrations of ANA, anti-double-stranded DNA, and anti-snRNP in the serum of MRL/LPR mice and alleviated apoptosis of Th1 and Th2 cells. VitD markedly increased the expression of T-bet and GATA mRNA in the spleen of MRL/LPR mice and consequently increased the levels of Wnt3a and ß-catenin. Western blot analysis revealed that the levels of GSK-3ß, p-ß-catenin, Wnt1, Wnt3a, c-myc, and cyclin D1 could be reduced by VitD, compared with MRL/LPR. Immunohistochemistry demonstrated that the expression of ß-catenin was the most pronounced in the spleen of MRL/LPR mice, and the expression level of ß-catenin decreased substantially after VitD intervention. CONCLUSIONS: VitD can further inhibit the nuclear translocation of ß-catenin by downregulating the expression of Wnt ligands (Wnt1 and Wnt3a), which reduces the expression of the downstream target gene cyclin D1. Systemic lupus erythematosus in mice was improved by inhibiting the activation of Wnt/ß-catenin signal pathway.

Vitamin D Activates miR-126a-5p to Target GSK-3ß and Alleviates Systemic Lupus Erythematosus in MRL/LPR Mice.

BACKGROUND: The etiology of systemic lupus erythematosus (SLE) is complex, and the disease is thus difficult to cure. In this regard, it has been established that SLE patients are characterized by differing levels of vitamin D-hydroxylation; however, the direct effects of vitamin D (VitD) in these patients remain unknown. OBJECTIVE: Therefore, we investigated the effects and mechanisms of action of VitD in the context of SLE. METHODS: The effects of VitD on MRL/LPR mice were studied by synthesizing glycogen synthase kinase-3ß (GSK-3ß)-interfering lentiviruses and transfecting with miR-126a-5p mimics. Changes in the body weight of mice were recorded for 6 weeks. Western blotting was performed to determine the levels of T-bet, GATA3, and GSK-3ß protein expression, and qRT-PCR was performed to determine the levels of miR-126a-5p and GSK-3ß mRNA expression. ELISA was performed to determine the levels of ANA, dsDNA, and snRNP/Sm in mice serum. RESULTS: GSK-3ß and miR-126a-5p were expressed at high and low levels, respectively, in MRL/LPR mice. VitD (30 ng/kg) was found to reduce the expression of GSK-3ß and increase miR-126a-5p expression, which targets GSK-3ß. T-bet and GATA3 were found to be positively regulated by miR-126a-5p and VitD and negatively regulated by GSK-3ß. The body weight of mice was not altered by VitD. ANA, dsDNA, and snRNP/Sm were positively regulated by miR- 126a-5p and VitD and negatively regulated by GSK-3ß. The effects of GSK-3ß were enhanced in response to the inhibition of miR-126a-5p expression. CONCLUSION: VitD upregulated miR-126a-5p to target GSK-3ß expression, thereby alleviating the SLE in MRL/LPR mice.