Objective: This study aimed to examine (1) whether polarity protein partitioning defective-3 (PARD-3) was expressed in endothelial cells (ECs) and contributed to endothelial barrier integrity and (2) whether altered PARD-3 expression and distribution were associated with disturbed endothelial junction protein VE-cadherin expression induced by factors derived from preeclamptic (PE) placentas. Methods: PARD-3 and VE-cadherin expressions were examined by immunofluorescent staining and Western blot in confluent ECs and in ECs treated with normal and PE placental conditioned medium (CM). Protein-protein interactions between PARD-3/VE-cadherin, PARD-3/ atypical protein kinase C (aPKCλ), and VE-cadherin/aPKCλ were examined by immuno-precipitation and immunobloting. Results: Similar to VE-cadherin, PARD-3 is localized at the cell contacts in control ECs. Both PARD-3 and VE-cadherin expressions were markedly reduced in cells treated with PE-CM for 2h, but not in cells treated with normal-CM compared to non-treated controls. Cytosol staining of VE-cadherin and PARD-3 was pronounced in cells after 24h treatment with PE-CM. PARD-3/VE-cadherin and PARD-3/aPKCλ complexes were detected in PE-CM treated cells, but not in untreated control cells and in cells after recovery. In contrast, VE-cadherin/aPKCλ complex was detected in control cells and in cells after recovery, but not in PE-CM treated cells. Conclusions: Polarity protein PARD-3 is localized at cell contacts. Factors-derived from PE placentas not only interrupt junction protein VE-cadherin distribution, but also perturb polarity protein PARD-3 expression and distribution in ECs. The results of PARD-3/VE-cadherin and PARD-3/aPKCλ complexes formation in cells treated with placental CM suggest that factors-derived from placenta could interfere both junction protein and polarity protein functions in ECs.
WangYGuYGrangerDNRobertsJMAlexanderJS. Endothelial junctional protein redistribution and increased monolayer permeability in HUVECs isolated during preeclampsia. Am J Obstet Gynecol. 2002;186(2):214–220.
GrotenTKreienbergRFialkaIHuberLWedlichD. Altered subcellular distribution of cadherin-5 in endothelial cells caused by the serum of pre-eclamptic patients. Mol Hum Reprod. 2000;6(11):1027–1032.
4.
ZhangYGuYLiHLucasMJWangY. Increased endothelial monolayer permeability is induced by serum from women with preeclampsia but not by serum from women with normal pregnancy or that are not pregnant. Hypertens Pregnancy. 2003;22(1):121–131.
5.
SchmoranzerJFawcettJPSeguraM. Par3 and dynein associate to regulate local microtubule dynamics and centrosome orientation during migration. Curr Biol. 2009;19(13):1065–1074.
6.
ZenKYasuiKGenY. Defective expression of polarity protein PAR-3 gene (PARD3) in esophageal squamous cell carcinoma. Oncogene. 2009;28(32):2910–2918.
7.
PegtelDMEllenbroekSIMertensAEvan der KammenRAde RooijJCollardJG. The Par-Tiam1 complex controls persistent migration by stabilizing microtubule-dependent front-rear polarity. Curr Biol. 2007;17(19):1623–1634.
8.
JobertyGPetersenCGaoLMacaraIG. The cell-polarity protein Par6 links Par3 and atypical protein kinase C to Cdc42. Nat Cell Biol. 2000;2(8):531–539.
9.
LinDEdwardsASFawcettJPMbamaluGScottJDPawsonT. A mammalian PAR-3-PAR-6 complex implicated in Cdc42/Rac1 and aPKC signalling and cell polarity. Nat Cell Biol. 2000;2(8):540–547.
10.
KanzakiMMoraSHwangJBSaltielARPessinJE. Atypical protein kinase C (PKCzeta/lambda) is a convergent downstream target of the insulin-stimulated phosphatidylinositol 3-kinase and TC10 signaling pathways. J Cell Biol. 2004; 164(2):279–290.
11.
IzumiYHiroseTTamaiY. An atypical PKC directly associates and colocalizes at the epithelial tight junction with ASIP, a mammalian homologue of Caenorhabditis elegans polarity protein PAR-3. J Cell Biol. 1998;143(1):95–106.
12.
SuzukiAIshiyamaCHashibaKShimizuMEbnetKOhnoS. aPKC kinase activity is required for the asymmetric differentiation of the premature junctional complex during epithelial cell polarization. J Cell Sci. 2002;115(pt 18):3565–3573.
13.
EbnetKSuzukiAHorikoshiY. The cell polarity protein ASIP/PAR-3 directly associates with junctional adhesion molecule (JAM). EMBO J. 2001;20(14):3738–3748.
14.
WangYAdairCDCoeLWeeksJWLewisDFAlexanderJS. Activation of endothelial cells in preeclampsia: Increased neutrophil-endothelial adhesion correlates with up-regulation of adhesion molecule P-selectin in human umbilical vein endothelial cells isolated from preeclampsia. J Soc Gynecol Investig. 1998;5(5):237–243.
15.
WangYAdairCDWeeksJWLewisDFAlexanderJS. Increased neutrophil-endothelial adhesion induced by placental factors is mediated by platelet-activating factor in preeclampsia. J Soc Gynecol Investig. 1999;6(3):136–141.
SuzukiAYamanakaTHiroseT. Atypical protein kinase C is involved in the evolutionarily conserved par protein complex and plays a critical role in establishing epithelia-specific junctional structures. J Cell Biol. 2001; 152(6):1183–1196.
18.
WangYDuDFangL. Tyrosine phosphorylated Par3 regulates epithelial tight junction assembly promoted by EGFR signaling. EMBO J. 2006;25(21):5058–5070.
