D-GLUCOSE INDUCES MICROTUBULAR CHANGES IN C1300 NEUROBLASTOMA CELL LINE THROUGH THE INCORPORATION OF 3-NITRO-L-TYROSINE INTO TUBULIN S. GADAU, G. LEPORE, M. ZEDDA, P. MANCA, V. CHISU, V. FARINA Department of Animal Biology, University of Sassari, Via Vienna, 2, 07100 Sassari, Italy ABSTRACT The microtubular network of neurons is involved in several functions such as formation and tropism of cellular processes, cell division and intracellular transport. A lot of evidences testify that the microtubular network of neurons can be impaired by oxidative stress. A con- dition of oxidative stress is often possible when D-glucose overloads its metabolic pathway, resulting in an increase in reactive oxygen species and subsequent neurological disorders. The aim of this work was to check in undifferentiated mouse neuroblastoma cells (C1300) the possible oxidative effects of D-glucose on microtubules. Using a concentration of 110mM D-glucose, cell morphology, growth rate, viability and catalase activity were seri- ously altered. Noteworthy, an increase in 3-nitro-L-tyrosine and a downregulation of tubu- lins was found in D-glucose-exposed cells, whereas another cytoskeletal proteins, namely actin, did not show any changes. In conclusion, microtubular network can be impaired by D-glucose through specific nitrosative effects, suggesting a possible mechanism at the basis of hyperglycemia-induced neuronal damage. INTRODUCTION Microtubules are dynamic polar formations which interact with a variety of cellular structures and molecules and are involved in critical events such as cell division, cell migra- tion and outgrowth of cellular processes (27, 28, 41, 53). Microtubules exhibit a state of extreme stability in neurons where they are especially abundant (4). In neurons, microtu- bular network can be impaired by several negative stimuli. One of these is represented by oxidative stress (2, 9, 36, 43), a condition where the production of free radicals exceeds the antioxidant capability of cells, with subsequent loss of cell functions and programmed cell death (5). It is known that all aerobic organisms are exposed to oxidative stress because reactive oxygen species, such as peroxynitrite, superoxide and hydrogen peroxide, are produced during mitochondrial respiration (13). Among cells, neurons exhibit an abnormal Corresponding Autor: Dr. Sergio Gadau, Dipartimento di Biologia Animale, Via Vienna 2, I-07100 Sassari - Tel. +39 079 229462 -Fax: +39 079 229432 - E-mail: sgadau@uniss.it Archives Italiennes de Biologie, 146: 107-117, 2008.