Effect of Berberis aetnensis C. Presl extract on tissue transglutaminase expression in primary astroglial cell cultures exposed to glutamate

Abstract number: 1733_300

Campisi A., Speciale A., Acquaviva R., Raciti G., Barbagallo I., Puglisi S., Iauk L.

Berberis aetnensis C. Presl (Berberidaceae) is a bushy spiny shrub presents on Mount Etna (Sicily). It contains several alkaloids showing several pharmacological properties (febrifugal, hypotensive, immunostimulating, antinflammatory). It is well known that excitotoxicity is a common feature in various neurological disorders. The excitotoxicity, increasing the intracellular calcium levels and activating specific genes, results in synthesis of several enzymes involved in cellular stress response, including tissue transglutaminase (TG-2). This is a multifunctional protein implicated in numerous cellular processes, as well as cellular differentiation, signal transduction, cell survival, and apoptosis. In previous researches, we demonstrated that the alterations of cellular redox state, evoked by glutamate in primary astrocyte cultures, are associated with the increase of TG-2 expression, and its effects were reduced by the antioxidant treatments.

In this study, we investigated the protective effects of B. aetnensis extract in glutamate-evoked TG-2 up-regulation in primary rat astroglial cell cultures.

Primary rat astroglial cell cultures were prepared from newborn albino cerebral cortex (1–2-day-old Wistar strain), maintained in cultures for two weeks, and exposed to 500 mM of glutamate for 24 hrs. Some cultures were also treated with the methanolic extract of plant roots at different concentrations and then exposed to the neurotransmitter.

The exposure of the astroglial cell cultures to glutamate caused a dose-dependent depletion of the glutathione levels, increased the reactive oxygen species (ROS) production and induced DNA fragmentation. The treatment of the cells with B. aetnensis extracts recovered the oxidative status and reduced the glutamate-increased of TG-2 expression.

These data suggest that B. aetnensis, preventing TG-2 up-regulation and reducing the oxidative stress induced by glutamate in primary astroglial cell cultures, may represent a new strategies in the neuropathological conditions associated to excitotoxicity.