1,25-Dihydroxyvitamin D3 increases the toxicity of hydrogen peroxide: the role of calcium and heat shock

Developmental vitamin D deficiency alters brain protein expression in the adult rat: implications for neuropsychiatric disorders

An increased risk for multiple sclerosis and schizophrenia is observed at increasing latitude and in patients born in winter or spring. To explore a possible link between maternal vitamin D deficiency and these brain disorders, we examined the impact of prenatal hypovitaminosis D on protein expression in the adult rat brain. Vitamin D-deficient female rats were mated with vitamin D normal males. Pregnant females were kept vitamin D-deficient until birth whereupon they were returned to a control diet. At week 10, protein expression in the progeny's prefrontal cortex and hippocampus was compared with control animals using silver staining 2-D gels associated with MS and newly devised data mining software. Developmental vitamin D (DVD) deficiency caused a dysregulation of 36 brain proteins involved in several biological pathways including oxidative phosphorylation, redox balance, cytoskeleton maintenance, calcium homeostasis, chaperoning, PTMs, synaptic plasticity and neurotransmission. A computational analysis of these data revealed that (i) nearly half of the molecules dysregulated in our animal model have also been shown to be misexpressed in either schizophrenia and/or multiple sclerosis and (ii) an impaired synaptic network may be a consequence of mitochondrial dysfunction.

Protection from cellular oxidative injury and calcium intrusion by N-(2-mercaptoethyl)-1,3-propanediamine, WR 1065

The radioprotective agent WR 2721 has been shown to prevent deterioration of renal function in a rodent model of chronic renal failure, and it has been suggested that WR 2721 may exert these protective effects by scavenging free radicals. To test this hypothesis, we investigated the effects of WR 2721 and its dephosphorylated, active metabolite, WR 1065, in an in vitro model of oxidative injury. By using the classical assay for superoxide production (reduction of ferricytochrome c), we first demonstrated that WR 1065 may act as a reducing agent. To establish the biological relevance of this reducing ability, U937 cells (a human premonocytic line) were incubated with or without WR 1065 or 2721, then exposed to increasing concentrations of H2O2. Cell viability was measured by Trypan blue exclusion and [3H]-thymidine incorporation into DNA, and cytosolic free calcium determined by fura-2 fluorescence. WR 1065 protected U937 cells from H2O2-induced cell death in a dose-dependent manner, and more efficiently than WR 2721. WR 1065 also prevented the rise in cytosolic free calcium induced in these cells by H2O2. These in vitro molecular and cellular events may account, at least in part, for the in vivo protective effects of WR 2721.