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. 2014 Jul 31;10(7):e1004470. doi: 10.1371/journal.pgen.1004470

Figure 5. Loss of matriptase and PAR-2 function impairs formation of the feto-maternal barrier.

Figure 5

(A). Relative uptake of the transcellular transport marker 3-methyl-D-glucose injected into the maternal bloodstream by E12.5–13.5 embryos. Placentas of matriptase (F2rl1+/+,St14−/−) or PAR-2 (F2rl1−/−;St14+/+) single-deficient embryos supported glucose transport at a rate comparable to the wildtype littermate controls (F2rl1+;St14+), whereas matriptase and PAR-2 double-deficient mice (F2rl1−/−;St14−/−) showed about 20% decrease in the glucose uptake (P<0.01). (B). Relative uptake of the paracellular transport marker carboxy-inulin injected into the maternal bloodstream by E12.5–13.5 embryos. Diffusion of carboxy-inulin across the placental epithelium was strongly dependent on gene dosage of both matriptase and PAR-2, showing 247% and 145%, respectively, increase in St14−/− and F2rl1−/− single-deficient embryos, and 402% and 351% increase, respectively, in F2rl1+/−;St14−/− and F2rl1−/−;St14+/− embryos, compared to the wildtype littermate controls. Highest levels of inulin transfer across the placenta, 589% above the control, was observed in mice with a combined matriptase and PAR-2 deficiencies (F2rl1−/−;St14−/−). (C). Expression of placental labyrinth differentiation markers syncytin A (upper panel) and GCMa (lower panel) in the placental tissues from E12.5 matriptase- and PAR-2-expressing (control, lanes 1–3) or matriptase- and PAR-2 double-deficient (F2rl1−/−;St14−/−, lanes 4–6) embryos. No change in the expression of either of the two proteins was detected. (D, E). Western blot analysis (D) and protein signal quantification (E) of the major structural components of epithelial tight junctions (claudin-1 and -2), adherens junctions (pan-cadherin), and desmosomes (desmoglein-1 and -2), or GAPDH as the protein loading control in the placental tissues from E12.5 matriptase- and PAR-2-expressing (control, lanes 1–4) or matriptase and PAR-2 double-deficient (F2rl1−/−;St14−/−, lanes 5–8) embryos. No significant differences were observed in the expression of claudin-2, cadherins, or desmoglein 1 and 2, whereas the expression of claudin-1 was significantly reduced. P values: *<0.05, ** <0.01, *** <0.001, N.S. = not significant, Student's t-test, two-tailed.