Systemic administration of synthetic glucocorticoid induces
PE-like features in pregnant rats
We then explored whether excess GCs mediate PE-like features caused by
placental 11β-HSD2 downregulation. As shown in Fig.3A&B, administration
of DEX from GD 7.5 and 17.5 could result in a significant increase in
SBP and protein/creatinine in urine. The rats with DEX treatment also
displayed abnormal renal morphology including hypercellularity in
mesangial and occlusion of capillary loops and the urinary space
(Fig.3C) and a higher histopathological score compared with control rats
(Fig.3D). As expected, elevated circulatory sFlt1 level and decreased
fetal weight were also found in DEX-treated dams (Fig.3E&F).
Placental
11β-HSD2 downregulation results in deficient invasion of interstitial
trophoblasts, impaired endovascular SA remodeling and reduced placental
blood flow
The area of interstitial trophoblast invasion in MT was measured for
evaluation of trophoblast invasion in uterus (Fig.4A). It was
significantly reduced in CBX (1.2 and 2.4 mg/kg) groups compared with
vehicle group (Fig.4B). Less trophoblasts infiltrated in SA higher
α-actin staining intensity in SA were found in CBX (1.2 and 2.4 mg/kg)
groups compared with vehicle group (Fig.4C). Abnormal morphology of
placenta was found in CBX (1.2 and 2.4 mg/kg) groups as evidenced by
disorganization in the labyrinth zone (Fig.4D) and reduced laminin
staining intensity compared with vehicle group (Fig.4E).
Specific delivery of CBX to placenta also led to impaired interstitial
trophoblast invasion and SA remodeling. The area of interstitial
trophoblast invasion was significantly decreased in CBX-CSA group
compared with vehicle. Higher α-actin staining intensity and less
trophoblast infiltration in SA were displayed in CBX-CSA group (Fig.5C).
Obvious morphological disturbance with disorganization in the labyrinth
zone and reduced laminin staining intensity in the placentas were also
exhibited in CBX-CSA group (Fig.5D&E). The animals of CBX-NPs and
CBX-SCR groups did not show abnormal interstitial trophoblast invasion,
trophoblast infiltration and placental morphology.
The placental blood flow was examined by using Doppler ultrasonography
(Fig.6A&B). The placental blood flow was significantly decreased in the
pregnant rats with CBX (1.2 and 2.4mg/kg) treatment as evidenced by a
significant reduction in peak systolic velocity (PSV) of SA, maternal
canal and umbilical artery compared with control rats (Fig.6C). As shown
in Fig.6D, CBX-CSA group also displayed a significant decrease in PSV
of
SA, maternal canal and umbilical artery. The rats of CBX-NPs and CBX-SCR
groups did not show reduced PSV of SA, maternal canal and umbilical
artery compared with control rats.
11β-HSD2 downregulation suppressestrophoblast
migration and invasion and promotes sFlt-1 release in the models of
cultured human trophoblasts
To extent our rodent studies, we investigate the role of 11β-HSD2 in PE
pathogenesis using human placental tissue and trophoblast modelsin vitro . At first, we examined whether 11β-HSD2 is involved in
regulation of the migration and invasion of extravillous trophoblast
(EVT) cell lines, HTR8 and HIPEC60. It was found that cortisol
(10-9M-10-6M) treatment did not
significantly affect the migration and invasion function
(supplemental
Fig. S6).
However,
cortisol (10-6M) significantly suppressed migration
and invasion in the cells transfected with 11β-HSD2 siRNA (supplemental
Fig.S6&7).
We then examined the role of 11β-HSD2 in regulation of PlGF and
sFlt1secretion in human placental explants and
cells.
In the presence of 11β-HSD2 inhibitor CBX
(10-6-10-5M), cortisol
(10-6M) treatment significantly increased sFlt1
release (Fig.7A) but did not significantly affect PlGF secretion in
placental explants (supplemental Fig. S8). Cortisol treatment also
significantly increased sFlt1 output in cultured primary
syncytiotrophoblasts with CBX treatment (Fig.7B). In the
syncytiotrophoblasts transfected with 11β-HSD2 siRNA, cortisol could
also promote sFlt1 secretion (Fig.7C). We then examined the effect of
cortisol on sFlt1 mRNA expression in order to study whether cortisol
promotes sFlt1 output via modulating sFlt1 transcript. However, cortisol
treatment had no impact on sFlt1 mRNA expression (supplemental Fig. S8).