Transport of lipids from golgi to plasma membrane is defective in tangier disease patients and Abc1-deficient mice

Mutations in the gene encoding ATP-binding cassette transporter 1 ( ABC1) have been reported in Tangier disease (TD), an autosomal recessive disorder that is characterized by almost complete absence of plasma high-density lipoprotein (HDL), deposition of cholesteryl esters in the reticulo-endothelial system (RES) and aberrant cellular lipid trafficking. We demonstrate here that mice with a targeted inactivation of Abc1 display morphologic abnormalities and perturbations in their lipoprotein metabolism concordant with TD. ABC1 is expressed on the plasma membrane and the Golgi complex, mediates apo-AI associated export of cholesterol and phospholipids from the cell, and is regulated by cholesterol flux. Structural and functional abnormalities in caveolar processing and the trans-Golgi secretory pathway of cells lacking functional ABC1 indicate that lipid export processes involving vesicular budding between the Golgi and the plasma membrane are severely disturbed.     

Effects of 9.4 GHz microwave exposure on meiosis in mice.

Exposure to 9.4 GHz pulsed microwaves at low power densities for 1 h/day during 2 weeks induces in adult male Balb/c mice disturbances in meiosis, consisting in an increase of translocations and the appearance of cells with several chromosome pair remaining univalents at MI.     

Differentiating effects of the glucagon-like peptide-1 analogue exendin-4 in a human neuronal cell model

Glucagon-like peptide-1 (GLP-1) is an insulinotropic peptide with neurotrophic properties, as assessed in animal cell models. Exendin-4, a GLP-1 analogue, has been recently approved for the treatment of type 2 diabetes mellitus. The aim of this study was to morphologically, structurally, and functionally characterize the differentiating actions of exendin-4 using a human neuronal cell model (i.e., SH-SY5Y cells). We found that exendin-4 increased the number of neurites paralleled by dramatic changes in intracellular actin and tubulin distribution. Electrophysiological analyses showed an increase in cell membrane surface and in stretch-activated-channels sensitivity, an increased conductance of Na⁺ channels and amplitude of Ca⁺⁺ currents (T- and L-type), typical of a more mature neuronal phenotype. To our knowledge, this is the first demonstration that exendin-4 promotes neuronal differentiation in human cells. Noteworthy, our data support the claimed favorable role of exendin-4 against diabetic neuropathy as well as against different neurodegenerative diseases.     

Effects of 9.4 GHz microwave exposure on meiosis in mice

Summary Exposure to 9.4 GHz pulsed microwaves at low power densities for 1 h/day during 2 weeks induces in adult male Balb/c mice disturbances in meiosis, consisting in an increase of translocations and the appearance of cells with several chromosome pair remaining univalents at MI.Acknowledgments. Grant No. 30121/120/53674 of the Centre International des Etudiants et Stagiaires to E. Manikowska and grant No. 78-1017/DRED of the Direction des Recherches et Etudes Techniques du Ministère de Défense to B. Servantie accorded by the French Government are gratefully acknowledged. The authors express their thanks to Miss M.R. Morazzani for her technical assistance.     

Absorption and translocation of tetrachlorodibenzo-p-dioxine by plants from polluted soil

Summary Measurements were made of contamination of plants grown in soil polluted with tetrachlorodibenzo-p-dioxine. Findings show that the pollutant is absorbed and translocated by the plants studied and suggest that the pollutant may be eliminated in the course of time.Acknowledgment. This research was sponsored by the Regional Government of Lombardy, Italy. The authors would like to thank Prof. Marrè for his continuous interest and for the fruitful discussion.     

Sphingosine 1-phosphate induces differentiation of adipose tissue-derived mesenchymal stem cells towards smooth muscle cells

Sphingosine 1-phosphate (S1P) is a bioactive sphingolipid which regulates multiple biological parameters in a number of cell types, including stem cells. Here we report, for the first time, that S1P dose-dependently stimulates differentiation of adipose tissue-derived mesenchymal stem cells (ASMC) towards smooth muscle cells. Indeed, S1P not only induced the expression of smooth muscle cell-specific proteins such as α-smooth muscle actin (αSMA) and transgelin, but also profoundly affected ASMC morphology by enhancing cytoskeletal F-actin assembly, which incorporated αSMA. More importantly, S1P challenge was responsible for the functional appearance of Ca²⁺ currents, characteristic of differentiated excitable cells such as smooth muscle cells. By employing various agonists and antagonists to inhibit S1P receptor subtypes, S1P₂ turned out to be critical for the pro-differentiating effect of S1P, while S1P₃ appeared to play a secondary role. This study individuates an important role of S1P in AMSC which can be exploited to favour vascular regeneration. Received 06 March 2009; accepted 17 March 2009