Fig. 1: Robust cis P-tau expression in PE placenta and trophoblast cells exposed to hypoxia.

a Immunoblots of placental protein extracts from gestational age-matched control (control; n = 3), early onset PE (e-PE; n = 3), and late onset PE (l-PE; n = 3) probed for cis and trans P-tau. b Sarkosyl soluble and insoluble fractions of placental extracts from age-matched controls (n = 7) and early-onset PE (e-PE; n = 7) were immunoprecipitated with HT7 (t-tau) and IgG antibodies before immunoblots against cis and trans P-tau. c Representative confocal images of human placental tissue sections from e-PE and age match control for double immunofluorescence with cis P-tau (green), trans P-tau (green), and ProteoStat (red). Inserts are magnified images of boxed areas. Cytotrophoblasts: complete arrow; syncytiotrophoblasts: incomplete arrows. Scale bar: 50 μm. Mean fluorescence intensity (MFI) quantification of cis P-tau, trans P-tau and ProteoStat positive protein aggregates in e-PE (d) and l-PE (e) placental sections (e-PE, n = 17; control, n = 16; l-PE, n = 19; control, n = 21, total 33–40 placental sections were analyzed per condition, two way ANOVA followed by Bonferroni’s post hoc test; mean±s.e.m. f Pearson’s colocalization coefficient (PCC) for cis P-tau and ProteoStat (left) is higher than for trans P-tau and ProteoStat (right); n = 35. Statistics are represented in the figure derived from two-tailed unpaired t test with Mann Whitney test.; mean±s.e.m. g Age-matched (control) and e-PE placental lysates were treated with (+λ) or without (-λ) lambda phosphatase (Ppase), followed by immunoblot with antibodies identifying early (cis P-tau and trans P-tau) or late (pS396) tau phosphorylation. Loading control was GAPDH. h Hypoxia-reoxygenation (H/R) stress induces robust cis P-tau aggregation. Human primary trophoblast cells were exposed to hypoxia (1% O₂) for 72 h followed by 2-3 h incubation in reoxygenation (21% O₂) conditions or normoxia environment (21% O₂). The merged picture with nuclear DAPI demonstrated co-localization. Inserts were enlargements of boxed portions. Images are representatives of n = 7 independent experiments, scale bar: 50 μm. i Disruption of β-tubulin positive microtubule network due to hypoxia in human primary trophoblast cells. ProteoStat positive protein aggregate puncta accumulated near damaged microtubule structure. Images are representatives of n = 5 independent experiments. Bar: 100 μm.