Hyperphosphorylation and accumulation of tau in neurons is one of the main pathologic hallmarks in Alzheimer’s disease (AD) and other tauopathies, including Pick’s disease (PiD), argyrophilic grain disease, familial frontotemporal dementia and parkinsonism linked to chromosome 17.
Hyperphosphorylated tau dissociates from microtubuli, resulting in the breakdown of the axonal flow, and thus impairs neuronal viability and function. Abnormal tau hyperphosphorylation is mainly induced due to the imbalance between protein kinases and phosphatases. To find promising drug candidates, inducible cellular models of tau hyperphosphorylation are useful screening tools for studying central nervous system drug effects.
Tau hyperphosphorylation was induced by hypothermic conditions (30 °C) in SH-SY5Y cells or SH-SY5Y cells overexpressing the longest isoform of human Tau441 carrying two well-characterized mutations V337M/R406W (SH-SY5Y-Tau441). To reverse tau hyperphosphorylation, cells were treated with LiCl, a well-known GSK3-β inhibitor, and either kept under normo- or hypothermic conditions. Afterwards, total tau and its phosphorylated species pSer262, pSer202, pSer396 and pThr231 were analyzed in cellular lysates by immunosorbent assay (Meso Scale Discovery, MSD).
Figure: Hypothermia induced tau hyperphosphorylation is significantly reduced by LiCl in SH-SY5Y-Tau441 (top) and SH-SY5Y cells (bottom). Cells were subjected to 2 h of hypothermia (30 °C) and treated with either LiCl or vehicle control (VC). Quantification of immunosorbent assay is shown for total tau, pTau202, pTau181 and pTau396. Data are normalized to normothermic conditions. Data are shown as mean + SEM (n=4). Statistical significance is indicated by *p<0.05, **p<0.01, ***p<0.001 as determined by One-Way ANOVA with Newman-Keuls post hoc test.