Fig. 2

Treatments with surfen and oxalyl surfen, but not hemisurfen, decrease tau hyperphosphorylation in Tg[HuC::hTau^P301L; DsRed] embryos in vivo. a ELISA quantification of pThr181 in 72 hpf Tg[HuC::hTau^P301L; DsRed] (hTau^P301L) embryos treated for 2 days in E3 medium containing 1% DMSO (hTau^P301L + 1% DMSO), 80 mM LiCl (hTau^P301L + LiCl), 3 μM surfen, (hTau^P301L + surfen), 2 μM oxalyl surfen (hTau^P301L + oxalyl surfen), or 3 μM hemisurfen (hTau^P301L + hemisurfen). The values were normalized to total human Tau protein recovered in each sample. pThr181 was significantly decreased in Tg[HuC::hTau^P301L; DsRed] embryos treated with LiCl, surfen and oxalyl surfen, but not hemisurfen (* P < 0.05, ns: not significant, Student’s t test). b Western blot analysis of pThr181 (AT270 antibody), pSer396/pSer404 (PHF1 antibody) and total-Tau (K9JA antibody) in 1% DMSO 72 hpf Tg[HuC::hTau^P301L; DsRed] (hTau^P301L) embryos and in age-matched siblings treated for 2 days with 80 mM LiCl, 3 μM surfen, 2 μM oxalyl surfen or 3 μM hemisurfen, confirmed that treatments with surfen or oxalyl surfen, but not hemisurfen, markedly reduce tau hyperphosphorylation in Tg[HuC::hTau^P301L; DsRed] embryos. c Densitometric analysis of AT270 on Western blots (represented in b) showing significant decrease of AT270/K9JA densitometric intensity ratio with LiCl, surfen and oxalyl surfen treatment, but not hemisurfen (n = 3, * P < 0.05, ns: non-significant, Student’s t test). d Densitometric analysis of PHF1 staining intensity on Western blots (represented in b) showing significant decrease of PHF1/K9JA densitometric intensity ratio with LiCl, surfen and oxalyl surfen treatment, but not hemisurfen (n = 3, * P < 0.05, ns: non-significant, Student’s t test). e Immunohistochemical visualization of total hTau protein (K9JA) and hyperphosphorylated tau epitope pSer202/pThr205 (AT8), and merged images of the two labelings (merge) in framed caudal area (f) in spinal cord of 72 hpf Tg[HuC::hTau^P301L; DsRed] embryos and age-matched siblings incubated for 2 days with 80 mM LiCl (hTau^P301L + LiCl), 3 μM surfen (hTau^P301L + surfen), 2 μM oxalyl surfen (hTau^P301L + oxalyl surfen) or 3 μM hemisurfen (hTau^P301L + hemisurfen), confirmed the decrease of tau hyperphosphorylation following treatments with surfen and oxalyl surfen. g Quantification of AT8 fluorescence intensity. The AT8/K9JA fluorescence intensity ratio was significantly decreased following treatments with LiCl, surfen and oxalyl surfen, but not hemisurfen (n = 10, * P < 0.05, ns: non-significant, Student’s t test). Scale bar: 50 μm