Abstract 042: Cd74-dysregulation of Macrophage-trophoblastic Interactions in the Preeclamptic Placenta
Objectives: Preeclamptic pregnancies feature placental anomalies. Villous trophoblast differentiation during placental development is regulated by feto-placental macrophages and disturbance of this well-balanced regulation can lead to pathological pregnancies. We hypothesized that Cluster of differentiation 74 (CD74) dysregulation of placental macrophages, leading to altered macrophage-trophoblast interaction, is involved in preeclampsia.
Methods and Results: We performed microarray analysis of placental tissue. CD74 was one of the most down-regulated (-2.5 fold) genes in placentas from preeclamptic women. We confirmed this finding in early onset (<34 gestational week, n=26) and late onset (≥34 gestational week, n=24) samples from preeclamptic women, compared to healthy pregnant controls (n=28) by real-time RT-PCR and on protein level by Western blot and flow cytometry. We localized CD74 expression in placental macrophages by immunofluorescence, flow cytometry, and real-time RT-PCR. Number and mean fluorescence intensity (MFI) of CD74-positive macrophages were significantly lower in preeclamptic placentas (7692 MFI ± 4402), as compared to controls (16283 MFI ± 3047). In CD74-silenced macrophages, expression of adhesion molecules ALCAM (-2 fold), ICAM4 (-2.1 fold), and Syndecan-2 (-1.9 fold) was lower compared to control. Macrophage adhesion to a trophoblast layer were diminished (-1.3 fold). Naïve and activated macrophages lacking CD74 showed a shift towards a pro-inflammatory signature with an increased secretion of TNFalpha(21.8 pg/ml ± 13.2 vs. 8 pg/ml ± 4.3), CCL5 (1.9 ng/ml ± 0.4 vs. 0.8 ng/ml ± 0.2) and MCP-1 (3 ng/ml ± 2.6 vs. 1 ng/ml ± 0.5), when co-cultured with trophoblasts compared to control macrophages. CD74-knockout mice showed disturbed placental morphology, reduced junctional zone (1.6 mm2 ± 0.3 vs. 2.3 mm2 ± 0.5) and smaller placentas (0.09 g ± 0.01 vs. 0.11 g ± 0.02) with fetal growth restriction (0.7 g ± 0.1 vs. 0.9 g ± 0.2) when compared to WT mice.
Conclusions: We found that CD74 downregulation in placental macrophages is present in preeclampsia. CD74 downregulation led to altered macrophage activation towards a pro-inflammatory signature, a disturbed crosstalk with trophoblasts and an abnormal placental morphology.
Author Disclosures: L. Przybyl: None. N. Haase: None. M. Golic: None. J. Rugor: None. M.E. Solano: None. P.C. Arck: None. M. Gauster: None. B. Huppertz: None. J. Bernhagen: None. R. Bucala: None. F.C. Luft: None. A.C. Staff: None. D.N. Mueller: None. R. Dechend: B. Research Grant (includes principal investigator, collaborator, or consultant and pending grants as well as grants already received); Modest; Deutsche Forschungsgemeinschaft (DFG). F. Herse: B. Research Grant (includes principal investigator, collaborator, or consultant and pending grants as well as grants already received); Modest; Deutsche Forschungsgemeinschaft (DFG).
- © 2015 by American Heart Association, Inc.