Curcumin and diabetes: a role for the vitamin D receptor?

An investigation of vitamin D status in alopecia areata

Alopecia areata (AA) is a type of non-scarring, recurrent patchy loss of hair in hair-bearing areas and is mostly of autoimmune origin. Previous studies have suggested that some autoimmune diseases were found to be associated with vitamin D deficiency. The current study was designed to assess the levels of serum 25-hydroxy vitamin D and C-reactive protein in AA, as compared with controls and to further identify the association between vitamin D levels and disease severity in patients with AA. This cross-sectional study included 45 patients with AA and 45 healthy volunteers. Clinical and anthropometric parameters were recorded, according to a pre-designed proforma. Serum 25-hydroxy vitamin D and high-sensitivity C-reactive protein were estimated using ELISA kits. The severity of AA was determined using Severity of Alopecia Tool (SALT) score. We observed a significant rise in systemic inflammation as seen by elevated high-sensitive C-reactive protein levels and lowered 25-hydroxy vitamin D levels in patients with alopecia areata, compared to controls (p = 0.001). The levels of 25-hydroxy vitamin D showed a significant negative correlation with disease severity, while hs-CRP levels showed a significant positive correlation with disease severity (ρ = - 0.714, p = 0.001 and ρ = 0.818, p = 0.001). Our results suggest significant systemic inflammation and vitamin D deficiency in alopecia areata, more so with increasing disease severity. This gains particular importance in the treatment of alopecia areata in future, as supplementing vitamin D to AA patients would result in reducing the disease severity and inducing remission.

Differential expression and regulation of prohibitin during curcumin-induced apoptosis of immortalized human epidermal HaCaT cells

Prohibitin (PHB), also known as inhibin, is important in cell proliferation, differentiation and apoptosis. This protein localizes to the inner membrane of mitochondria, where it acts as a chaperone protein, and is also found in the nucleus, where it negatively regulates transcription. The tumor-suppressive role of PHB in cell proliferation appears to be contradictory. In this study, we investigated the existence, localization and alterations in the expression of PHB in the whole cell and nuclear matrix and analyzed its co-localization with the expression products of related genes. The western blot analysis results revealed that PHB exists in the composition of nuclear matrix proteins and that the expression level of PHB is significantly increased in the whole cell and markedly decreased in the nuclear matrix after curcumin (1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione) treatment. The laser confocal scanning microscope results demonstrated the co-localization of PHB with p53, c-Myc, Bax, and Fas in HaCaT cells, and this co-localization region was transferred as a result of curcumin treatment. In addition, the results of the GST pull-down assay demonstrated the direct interaction of PHB with p53, c-Myc and Bax but not Fas in vitro. Results of the present study confirmed that the expression and distribution of PHB, which is a nuclear matrix protein, affect the apoptosis of HaCaT cells and its co-localization with specific gene products connected with cell apoptosis.