PHORBOL ESTER ENHANCES PHOSPHORYLATED TAU-PROTEIN IMMUNOREACTIVITY INNEURONAL CULTURES

One of the hallmarks of Alzheimer's disease (AD) is neurofibrillary de generation which results from the aggregation of phosphorylated tau pr oteins into paired helical filament (PHF) structures. AD(2) is a new m onoclonal antibody raised against PHF tau which detects neurofibrillar y tangles in AD brain. In primary neuronal cultures, phorbol ester tre atment induced a time- and dose-dependent increase in AD(2) immunoreac tivity quantified by laser confocal microscopy and immunoblottings. Al kaline phosphatase treatment reversed these immunocytochemical changes . These results suggest that the modifications of neuronal metabolism induced by phorbol ester including protein kinase C activation produce an increase in phosphorylated tau immunoreactivity.