A Novel Tauopathy 3D-Culture Model on a Biochip Figure 3. Quantification of tau-specific impedimetric and morphologic alterations induced by okadaic acid treatment. A. SH-SY5Y spheroids expressing WT, P301L and K280q tau were treated with 5 nM, 10 nM, 25 nM and 100 nM okadaic acid (OA) for 24, 48 and 72 hours. Statistical analysis of relative impedance changes normalized to experimental start (100%) and the control revealed tau mutation dependent degeneration of spheroids. B. Analysis of cross section area showed a different mutation dependent pattern. (n = 30, *p,0.05, **p,0.01, ***p,0.001) C. Example microscopic images of WT and K280q tau expressing spheroids after 24 and 72 hours. (bar = 100 mm) D. For analysis of morphological and tau localization alterations, five days cultivated WT and K280q spheroids were incubated with 25 nM OA for 72 hours. Live cell imaging of EGFP- fused untreated WT and K280q tau-expressing spheroids showed the ordered arrangement (arrowheads) of microtubule-associated tau protein especially in the long neuronal processes (arrows). Incubation with OA led to a degeneration of cells and alteration of tau localization (arrows) as well as accumulation (arrowheads) in WT and moreover K280q spheroids. (bar = 50 mm). doi:10.1371/journal.pone.0049150.g003 expressing 3D cultures. Furthermore, there were hints that high concentrations of especially hymenialdisine and methylene blue caused cytotoxicity, whereas particularly AR-A014418 showed protective effects over a wide concentration range. However, the spheroid cross section area was not intensively affected by tau- focused therapeutic treatment indicating the high sensitivity of our impedance screening system to detect cellular recovery processes. PLOS ONE | www.plosone.org 6 November 2012 | Volume 7 | Issue 11 | e49150