Overexpression of cellular prion protein induces an antioxidant environment altering T cell development in the thymus.

Cellular prion protein (PrP(C)) is an ubiquitously expressed glycoprotein whose roles are still widely discussed, particularly in the field of immunology. Using TgA20- and Tg33-transgenic mice overexpressing PrP(C), we investigated the consequences of this overexpression on T cell development. In both models, overexpression of PrP(C) induces strong alterations at different steps of T cell maturation.

Mitochondrial production of reactive oxygen species and incidence of age-associated lymphoma in OF1 mice: effect of alternate-day fasting.

There is currently of a great interest investigating the role of nutrition in the prevention of age-associated disorders. The present study aimed to evaluate, on a particular strain of mice, the efficacy of alternate-day fasting on the mitochondrial production of free radical species and on the incidence of a specific cancer (lymphoma) in aged mice. Alternate fasting, that was initiated in middle age mice through a 4 month period, reduced significantly the incidence of lymphoma (0% versus 33% for controls).

Iodine and/or selenium deficiency alters tissue distribution pattern of other trace elements in rats.

Tissue distribution of Fe, Mn, Cu, and Zn, the essential trace elements associated with oxidant and/or antioxidant processes, was examined in iodine- and/or selenium-deficient rats (ID, SeD, ISeD). Fe and Mn were the most affected minerals in all types of deficiency states. Mn levels decreased significantly in the liver in all deficiency states (approx 20-30%), in the heart in ID and SeD rats (approx 30-35%) and in the testis in ID rats (approx 15%).

Prion infection impairs copper binding of cultured cells.

The molecular mechanism of neurodegeneration in transmissible spongiform encephalopathies (TSEs) remains unclear. Using radioactive copper ((64)Cu) at physiological concentration, we showed that prion infected cells display a marked reduction in copper binding. The level of full-length prion protein known to bind the metal ion was not modified in infected cells, but a fraction of this protein was not releasable from the membrane by phosphatidylinositol-specific phospholipase C.

Expression of prion protein increases cellular copper binding and antioxidant enzyme activities but not copper delivery.

The N-terminal region of the prion protein PrP(C) contains a series of octapeptide repeats. This region has been implicated in the binding of divalent metal ions, particularly copper. PrP(C) has been suggested to be involved in copper transport and metabolism and in cell defense mechanisms against oxidative insult, possibly through the regulation of the intracellular CuZn superoxide dismutase activity (CuZn-SOD) or a SOD-like activity of PrP(C) itself.

The effect of a water-dispersible beta-carotene formulation on the prevention of age-related lymphoid neoplasms in mice.

There is currently a great interest in the efficiency of micronutrients against age-associated disorders. The present study aimed to evaluate the efficacy of beta-carotene on the incidence of lymphoid neoplasia, a fatal pathology associated with OFI mouse ageing. Beta-carotene, given as a water-dispersible preparation to 8-month-old mice, on a four month follow-up study, significantly reduced the incidence of neoplasm (12.