S100b Induces Expression of Myoglobin in APß Treated Neuronal Cells In Vitro: A Possible Neuroprotective Mechanism.

BACKGROUND: In this study, human neuroblastoma cells (IMR32) treated with Amyloid Beta Peptide (APß), were used as model to evaluate the molecular basis of protective role of S100b, a neurotrophic factor and neuronal survival protein, highly expressed by reactive astrocytes close to amyloid deposition in the cortex of Alzheimer's patients. The aim of this work is to value the effect of S100b on ROS production in cells treated with Amyloid Beta Peptide and the subsequent influence on globin gene expression. METHOD: In this study we investigated the effect of S100b on ROS production and on globin gene expression in human neuroblastoma cells (IMR32) treated with Amyloid Beta Peptide (APß). RESULTS: Our results have shown that at nanomolar concentrations, S100b protects cells against AP. mediated cytotoxicity and the protective mechanism could be related, almost in part, to the control of ROS production through an over expression of Myoglobin gene. CONCLUSION: In light of our results, we speculate that over-expression of the Myoglobin gene could be read as a possible attempt of the cell to increase the scavengers of reactive oxygen species (ROS).

Fibroblast apoptosis in a patient affected by lamellar ichthyosis.

BACKGROUND: Lamellar ichthyosis (LI) is a congenital recessive skin disorder characterized by generalized scaling and hyperkeratosis. The pathology may be caused by mutations in transglutaminase 1 (TGM1) gene that encodes an enzyme critical for terminally differentiating keratinocytes. Because of evidences that transglutaminase enzymes are involved in programmed cell death, we investigated morphological and biochemical apoptotic parameters in cultured skin fibroblasts from a patient with a severe LI and homozygous for the TGM1 R142H mutation. METHOD: The principle apoptotic signals (mitochondrial membrane potential, analysis of oxygen consumption, DNA fragmentation and Bax/Bcl-2 gene expression) were analyzed in cultured fibroblasts from a LI patient, his mother (TGM1 mutation carrier) and a control subject. RESULTS: LI fibroblasts showing a reduction of fibronectin expression evidenced a strong inhibition of oxygen consumption, a dramatic drop in the mitochondrial membrane potential (Delta psi(m)), and a higher apoptotic index. CONCLUSION: The present results suggest a possible connection between the alterations in the keratinization process leading to LI and the observed increased fibroblast apoptosis.