Heat shock protein 27 reduces phosphorylated tau and rescues cell death in human neuroblastoma cell line SH-SY5Y

Abstract

The two pathological hallmarks characterizing Alzheimers disease are the formation of extracellular deposit of amyloid-β in the form of senile plaques and intracellular neurofibrillary tangles (NFTs), which consist of pathological hyperphosphorylated tau protein aggregated into insoluble paired helical filaments (PHFs). Tau protein, a microtubule-associated protein, is abundant in neurons of the central nervous system. To keep nerves functioning properly, it stabilizes microtubules, which are important for supporting cell structure and cellular processes. When tau protein is modified, it stops functioning and a cell cant maintain cell structure. Therefore hyperphosphorylated tau is believed to be a pathological hallmark of Alzheimers disease. Heat shock protein 27(Hsp27), one of the sHsp (small heat shock protein) group, is known as a chaperone, which prevents protein aggregation and stabilizes denatured protein. Here we show that Hsp27 reduces hyperphosphorylated tau by helping its degradation. Moreover, Hsp27 rescues from hyperphosphorylated tau mediated cell death in neuroblastoma cell line SH-SY5Y.