Suppression of PrPSc- and HIV-1 gp120 induced neuronal cell death by sulfated colominic acid

The scrapie prion protein (PrPSc) has been shown to induce apoptosis of rat cortical neurons in vitro. Here we demonstrate that the toxic effect displayed by PrPSc can be blocked by sulfated colominic acid (polymer of N-acetylneuraminic acid). This compound acts neuroprotectively at a concentration of ≥ 0.3 μg/ml when preincubated with the neurons or PrPSc. Rat cortical cells also undergo apoptosis after incubation with the HIV-1 coat protein gp120 in vitro. This effect was abolished also by sulfated colominic acid when preincubated with the cells or gp120. Addition of 0.3 μg/ml of compound resulted in an increase in cell viability by about 1.6-1.9-fold compared to cultures incubated for 18 h with 30 ng/ml of PrPSc or 20 ng/ml of gp120 alone (containing about 40% viable cells). Sulfated colominic acid does not act as antagonist of NMDA receptor channels at concentrations of up to 3 μg/ml when co-administered with 100 μg/ml of NMDA. It displayed a strong cytoprotective effect on human T lymphoblastoid CEM ...