Placental Growth Factor mRNA Expression Research Articles

Increased Interleukin-36β Expression Promotes Angiogenesis in Japanese Atopic Dermatitis

While atopic dermatitis (AD) is considered as a T helper 2 (Th2)-centered disease, an increase in other types of inflammatory cytokines is also noted in AD and they may also contribute to the development of the disease. Recently, the efficacy of an anti-IL-36 receptor antibody in AD was demonstrated in a clinical trial. Although there have been several reports on IL-36α and IL-36γ expression and function in AD, IL-36β has been barely studied. In this report, we examined IL-36β expression and function using clinical samples of AD and the epidermal keratinocyte cell line, HaCaT cells. We demonstrated that IL-36β expression in epidermal keratinocytes was increased in AD lesional skin compared to healthy skin. IL-36β promoted vascular endothelial growth factor A production in HaCaT keratinocytes through phosphorylation of extracellular signal-regulated kinases 1 and 2. In addition, IL-36β up-regulated placental growth factor mRNA expression in HaCaT keratinocytes. IL-36β expression levels in epidermal keratinocytes were correlated with the number of dermal vessels in AD skin. These results suggest that IL-36β may play an important role for angiogenesis in lesional skin of AD and that IL-36β can be a therapeutic target in AD.

Association of Low Placental Growth Factor Gene Expression with Maternal and Neonatal Outcomes in Type 1 Diabetes: A Single Center, Cross-Sectional Study

Objective : The placental growth factor (PlGF) plays a crucial role in early and late pregnancy placental development. Pregestational type 1 diabetes (T1D) is a pregnancy complication that may lead to serious fetomaternal complications. Our study analyzed the association between placental PlGF mRNA expression and metabolic control, fetal weight and development in women with T1D. Materials and methods : A cross-sectional study on 65 pregnant women with T1D in singleton pregnancies admitted to the tertiary-level perinatal care unit. The study examined associations between the placental mRNA-PlGF gene expression measured with quantitative real-time PC and markers of maternal metabolism in the third trimester. The expression was also compared across maternal subgroups stratified according to the birth weight (small- vs. appropriate- vs. large-for-gestational age; SGA, AGA, LGA, respectively) and the following neonatal outcomes: mode of delivery, Apgar score and pH in the umbilical vessels. Results : Placental PlGF mRNA expression was significantly lower in SGA than in AGA and LGA patients (0.60 ± 0.34 vs. 0.63 ± 0.54 vs. 1.02 ± 0.15, respectively, p < 0.05). In the SGA group, the expression of the PlGF-mRNA correlated positively with maternal 3 rd trimester BMI (r = 0.49, p = 0.04), pH and BE cord blood values, and maternal 3 rd trimester mean BP. There was no correlation between 3 rd -trimester glycated hemoglobin and mean blood glucose levels (MBG) and PlGF expression. Conclusions : Our data suggest that lower PlGF mRNA expression may predict neonatal outcomes in women with T1D giving birth to SGA newborns.

Combining metformin and sulfasalazine additively reduces the secretion of antiangiogenic factors from the placenta: Implications for the treatment of preeclampsia

IntroductionThe antiangiogenic factors soluble fms-like tyrosine kinase-1 (sFlt-1) and soluble endoglin (sENG) are elevated in preeclampsia and have been implicated in its pathogenesis. We have previously demonstrated metformin and sulfasalazine independently reduce antiangiogenic factor secretion. Here we examined whether combining metformin and sulfasalazine may be more effective than either alone in reducing placental expression and secretion of antiangiogenic and angiogenic factors and the expression of markers of endothelial dysfunction. MethodsWe performed functional experiments using primary human placenta to explore the effect of metformin and sulfasalazine, at lower doses than previously explored, individually and in combination, on sFlt-1 and sENG secretion and placental growth factor (PlGF) and vascular endothelial growth factor (VEGFα) expression. Using primary endothelial cells we induced dysfunction using cytokine tumor necrosis factor-α (TNF-α) and assessed the effect of low dose combination treatment on the expression of vascular cell adhesion molecule-1 (VCAM-1) and Endothelin-1 (a potent vasoconstrictor). ResultsWe demonstrated combination metformin and sulfasalazine was additive in reducing sFlt-1 secretion from cytotrophoblasts and placental explants. Combination treatment was also additive in reducing sENG secretion from placental explants. Furthermore, combination treatment increased cytotrophoblast VEGFα mRNA expression. Whilst combination treatment increased PlGF mRNA expression this was similar to treatment with sulfasalazine alone. Combination therapy reduced TNFα induced endothelin-1 mRNA expression however did not change VCAM expression. DiscussionLow dose combination metformin and sulfasalazine reduced cytotrophoblast sFlt-1 and sENG secretion, increased VEGFα expression and reduced TNFα induced endothelin-1 expression in primary endothelial cells. Combination therapy has potential to treat preeclampsia.

Lower S-adenosylmethionine levels and DNA hypomethylation of placental growth factor (PlGF) in placental tissue of early-onset preeclampsia-complicated pregnancies.

IntroductionThe pathophysiology of preeclampsia is largely unknown. Serum placental induced growth factor (PlGF) levels are decreased during second trimester pregnancy. Aberrant DNA methylation is suggested to be involved in the etiology of preeclampsia (PE). We hypothesize that DNA methylation is altered in PE placentas determined the methylation index by measuring placental S-adenosylmethionine (SAM) and S-adenosylhomocysteine (SAH) levels. In addition, we assessed global DNA methylation status by long-interspersed nuclear element-1 (LINE-1) and DNA methylation status of the PlGF gene.MethodsPlacental tissue of 11 early onset PE (EOPE), 11 late onset PE (LOPE) and 60 controls consisting of 25 uncomplicated controls 20 fetal growth restriction (FGR) and 15 preterm births (PTB) controls was collected from a nested case-control study of The Rotterdam Periconceptional Cohort. RNA and DNA was isolated from placental tissue and DNA was treated with sodium bisulfite. SAM and SAH levels were measured by LC-ESI-MS/MS. Methylation of LINE-1 and PlGF genes was analyzed by Sequenom Epityper and. mRNA expression of PlGF was assessed with qPCR. Differences were assessed by analysis of covariance (ANCOVA) corrected for gestational age and birth weight.ResultsPlacental SAM levels were significantly lower in placental tissue of EOPE pregnancies compared to PTB controls (mean difference -240 ± 71.4 nmol/g protein, P = 0.01). PlGF DNA methylation was decreased in placental tissue of EOPE cases versus LOPE (mean difference -17.4 ± 5.1%, P = 0.01), uncomplicated controls (mean difference -23.4 ± 5.4%%, P <0.001), FGR controls (mean difference -17.9 ± 4.6%, P = 0.002) and PTB controls (mean difference -11.3 ± 3.8% P = 0.04). No significant differences were observed in SAH, SAM:SAH ratio, LINE-1 DNA methylation and PlGF mRNA expression between groups.DiscussionThe hypomethylation state of the placenta in EOPE, which is reflected by lower SAM and PlGF DNA hypomethylation underlines the possible role of placental DNA hypomethylation in the pathophysiology of EOPE, which needs further investigation.

Effect of placental growth factor in models of experimental pre-eclampsia and trophoblast invasion.

Placental growth factor (PlGF) is decreased in early gestation of pregnant women who subsequently develop pre-eclampsia. In this study, pre-emptive treatment with PlGF to prevent pre-eclampsia was evaluated in an in vivo rodent model of experimental pre-eclampsia (EPE) induced by TNF-α and in an in vitro model of human first-trimester trophoblast invasion. Pregnant C57/BL6 mice were treated with recombinant mouse placental growth factor-2 (rmPlGF-2) 100μg/kg/day IP from gestational day (gd) 10. Animals had EPE induced by continuous TNF-α infusion on gd 13 and were subject to either continuous blood pressure monitoring by radiotelemetry throughout pregnancy or live placenta T2 -weighted magnetic resonance imaging (MRI) to demonstrate placental function on gd 17. There was no difference in BP (P>.99), proteinuria (P=.9) or T2 values on MRI (P=.9) between control and rmPlGF-2-treated animals. On gd 13, animals treated with rmPlGF-2 demonstrated increased placenta PlGF (P=.01) and Toll-like receptor-3 (P=.03) mRNA expression as compared with controls. Fluorescent-labelled human uterine microvascular endothelial cells and HTR8/SVNeo cells were co-cultured on Matrigel™ and treated with recombinant human PlGF (rhPlGF) (10ng/mL) and/or TNF-α (0.5ng/mL). Trophoblast integration into endothelial networks was reduced by added TNF-α (P=.006), as was rhPlGF concentration in conditioned media (P<.0001). Cell integration was not ameliorated by addition of rhPlGF (P>.9). Although TNF-α-induced EPE was not reversed with pre-emptive rmPlGF-2, a further trial of pre-emptive rhPlGF in vivo is required to determine whether the absence of effect of rhPlGF demonstrated in vitro precludes PlGF as a preventative therapy for pre-eclampsia.

Different effects of pravastatin on sFlt-1, PlGF and VEGF in different preeclampsia-like mouse models

Objective: To explore the pathways of preeclampsia by investigating different effects of pravastatin (Pra) on and soluble FMS tyrosine kinase-1 (sFlt-1), placental growth factor (PlGF) and vascular endothelial growth factor (VEGF) in different preeclampsia (PE)-like mouse models. Methods: C57BL/6J mice were randomly subcutaneously injected with N-nitro-L-arginine methyl ester (L-NAME) or intraperitoneally injected with lipopolysaccharide (LPS) as PE-like mouse model, saline as normal pregnancy control (Con) respectively, daily at gestational 7-18 days. Pra was given daily at gestational 8-18 days in each model group and the mice were divided into Pra (L-NAME+Pra, LPS+Pra, Con+Pra) and saline (L-NAME+NS, LPS+NS, Con+NS) groups. Liver,placental tissue and blood of pregnant mice were collected on the 18th day of pregnancy. The levels of VEGF, PlGF and sFlt-1 in the liver, placenta and serum of mice in each group were compared by western blot, ELISA and real-time fluorescence quantitative PCR (RT-PCR). Results: (1) ELISA: Serum VEGF (205.70±3.43, 154.60±2.31) and PlGF (131.5±3.75, 101.50±4.31) levels were significantly increased in L-NAME+Pra group compared with L-NAME+NS group (all P<0.05). Serum VEGF (202.30±4.90, 144.50±6.71) and PlGF (121.50±3.86, 95.41±4.08) levels were significantly higher in LPS+Pra group than those in LPS+NS group (all P<0.05). Serum sFlt-1 level in LPS+Pra group was significantly lower than that in LPS+NS group (3.01±0.50, 776.60±80.06), serum sFlt-1 level in L-NAME+Pra group was significantly lower than that in L-NAME+NS group (2.60±0.06, 583.70±9.83; all P<0.05). (2) Western blot: the expression levels of PlGF (1.344±0.118, 0.664±0.143) and VEGF (1.34±0.12, 0.66±0.14) in the liver of mice in the L-NAME+Pra group were significantly higher than those in the L-NAME+NS group (all P<0.05), but the expression levels of PlGF and VEGF in the placenta of L-NAME+Pra group were not significantly different from those of L-NAME+NS group (all P>0.05). The expression levels of PlGF and VEGF in placenta and liver of pregnant mice in LPS+Pra group were not significantly different from those in LPS+N group (all P>0.05). (3) RT-PCR: the mRNA expression of PlGF and VEGF in placenta and liver of L-NAME+Pra group were not significantly different from those in L-NAME+NS group (all P>0.05). The mRNA expression levels of PlGF and VEGF in placenta and liver of LPS+Pra group were not significantly different from those of LPS+NS group (all P>0.05). Conclusions: Pra has different regulatory effects on vascular endothelial function in different PE-like models. It reveals that different pathogenesis and pathways exist in different PE-like changes.

Differential Expression of Placental Growth Factor, Transforming Growth Factor-β and Soluble Endoglin in Peripheral Mononuclear Cells in Preeclampsia.

To measure the peripheral blood mononuclear cells (PBMCs) mRNA expression of placental growth factor (PlGF), Transforming growth factor beta (TGF-β), and soluble Endoglin (sEng) in the blood of preeclamptic and normotensive pregnant women. Cross-sectional analytical study. Department of Physiology and Cell Biology, University of Health Sciences, Lahore, from November 2016 to April 2018. The study included 50 normotensive and 57 preeclamptic patients (18-40 years of age), all in the third trimester of pregnancy. The preeclamptic group was further divided into early-onset preeclampsia (EOP) and late-onset preeclampsia (LOP). Blood samples from patients and healthy controls were collected and mRNA expression was measured (18 patients and 18 controls) by real time PCR. Statistical analyses were done using SPSS (version 22). The values were considered significant at 0.05 level of significance. The PBMCs mRNA expression of PlGF, TGF- and sEng were significantly different between the preeclampsia and control group (p<0.001). A significant decrease in expression of TGF- was observed in LOP group compared to controls (p<0.001); whereas, the difference in the expression of EOP compared to controls was not significant (p=0.12). Similar to TGF-, the expression of PlGF was significantly decreased among EOP and LOP compared to controls. Detailed analysis of sEng showed significantly increased expression in both EOP and LOP as compared to healthy group (p<0.001). There is a significant difference in extra-placental expression of PlGF, and sEng in preeclampsia.

Proton Pump Inhibitors Quench the Pathophysiological Characteristics of Preeclampsia in Both Human and Mouse Models and Represent an Exciting Novel Candidate Therapeutic

The antiangiogenic factors soluble fms-like tyrosine kinase-1 (sFlt-1) and soluble endoglin (sENG) are elevated in preeclampsia and have been implicated in its pathogenesis. We have previously demonstrated metformin and sulfasalazine independently reduce antiangiogenic factor secretion. Here we examined whether combining metformin and sulfasalazine may be more effective than either alone in reducing placental expression and secretion of antiangiogenic and angiogenic factors and the expression of markers of endothelial dysfunction.We performed functional experiments using primary human placenta to explore the effect of metformin and sulfasalazine, at lower doses than previously explored, individually and in combination, on sFlt-1 and sENG secretion and placental growth factor (PlGF) and vascular endothelial growth factor (VEGFα) expression. Using primary endothelial cells we induced dysfunction using cytokine tumor necrosis factor-α (TNF-α) and assessed the effect of low dose combination treatment on the expression of vascular cell adhesion molecule-1 (VCAM-1) and Endothelin-1 (a potent vasoconstrictor).We demonstrated combination metformin and sulfasalazine was additive in reducing sFlt-1 secretion from cytotrophoblasts and placental explants. Combination treatment was also additive in reducing sENG secretion from placental explants. Furthermore, combination treatment increased cytotrophoblast VEGFα mRNA expression. Whilst combination treatment increased PlGF mRNA expression this was similar to treatment with sulfasalazine alone. Combination therapy reduced TNFα induced endothelin-1 mRNA expression however did not change VCAM expression.Low dose combination metformin and sulfasalazine reduced cytotrophoblast sFlt-1 and sENG secretion, increased VEGFα expression and reduced TNFα induced endothelin-1 expression in primary endothelial cells. Combination therapy has potential to treat preeclampsia.

Increased placental sFlt-1 but unchanged PlGF expression in late-onset preeclampsia

ABSTRACTObjective: To investigate whether differences between late-onset preeclampsia (PE) and intrauterine growth restriction (IUGR) can be explained by differential placental expression patters of sFlt-1, Flt-1, and placental growth factor (PlGF).Methods: Placental tissues and maternal blood samples from seven patients with PE, five IUGR, and seven age-matched controls were studied for mRNA and protein levels as well as protein localization and expression intensity.Results: Placental PlGF mRNA and protein expression were not altered by placental dysfunction while placental villous trophoblast expression intensity of PlGF was increased.Conclusion: High sFlt-1 concentrations may account for diminished maternal serum PlGF levels.

Placental endoplasmic reticulum stress negatively regulates transcription of placental growth factor via ATF4 and ATF6β: implications for the pathophysiology of human pregnancy complications.

Low maternal circulating concentrations of placental growth factor (PlGF) are one of the hallmarks of human pregnancy complications, including fetal growth restriction (FGR) and early‐onset pre‐eclampsia (PE). Currently, PlGF is used clinically with other biomarkers to screen for high‐risk cases, although the mechanisms underlying its regulation are largely unknown. Placental endoplasmic reticulum (ER) stress has recently been found to be elevated in cases of FGR, and to an even greater extent in early‐onset PE complicated with FGR. ER stress activates the unfolded protein response (UPR); attenuation of protein translation and a reduction in cell growth and proliferation play crucial roles in the pathophysiology of these complications of pregnancy. In this study, we further identified that ER stress regulates release of PlGF. We first observed that down‐regulation of PlGF protein was associated with nuclear localization of ATF4, ATF6α and ATF6β in the syncytiotrophoblast of placentae from PE patients. Transcript analysis showed a decrease of PlGF mRNA, and an increase from genes encoding those UPR transcription factors in placentae from cases of early‐onset PE, but not of late‐onset (>34 weeks) PE, compared to term controls. Further investigations indicated a strong correlation between ATF4 and PlGF mRNA levels only (r = − 0.73, p < 0.05). These results could be recapitulated in trophoblast‐like cells exposed to chemical inducers of ER stress or hypoxia–reoxygenation. The stability of PlGF transcripts was unchanged. The use of small interfering RNA specific for transcription factors in the UPR pathways revealed that ATF4 and ATF6β, but not ATF6α, modulate PlGF transcription. To conclude, ATF4 and ATF6β act synergistically in the negative regulation of PlGF mRNA expression, resulting in reduced PlGF secretion by the trophoblast in response to stress. Therefore, these results further support the targeting of placental ER stress as a potential new therapeutic intervention for these pregnancy complications. © 2015 The Authors. Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Fluid shear stress upregulates placental growth factor in the vessel wall via NADPH oxidase 4.

Placental growth factor (PLGF), a potent stimulator of arteriogenesis, is upregulated during outward arterial remodeling. Increased fluid shear stress (FSS) is a key physiological stimulus for arteriogenesis. However, the role of FSS in regulating PLGF expression is unknown. To test the hypothesis that FSS regulates PLGF expression in vascular cells and to identify the signaling pathways involved, human coronary artery endothelial cells (HCAEC) and human coronary artery smooth muscle cells were cultured on either side of porous Transwell inserts. HCAEC were then exposed to pulsatile FSS of 0.07 Pa ("normal," mimicking flow through quiescent collaterals), 1.24 Pa ("high," mimicking increased flow in remodeling collaterals), or 0.00 Pa ("static") for 2 h. High FSS increased secreted PLGF protein ∼1.4-fold compared with static control (n = 5, P < 0.01), while normal FSS had no significant effect on PLGF. Similarly, high flow stimulated PLGF mRNA expression nearly twofold in isolated mouse mesenteric arterioles. PLGF knockdown using siRNA revealed that HCAEC were the primary source of PLGF in cocultures (n = 5, P < 0.01). Both H2O2 and nitric oxide production were increased by FSS compared with static control (n = 5, P < 0.05). N(G)-nitro-l-arginine methyl ester (100 μM) had no significant effect on the FSS-induced increase in PLGF. In contrast, both catalase (500 U/ml) and diphenyleneiodonium (5 μM) attenuated the effects of FSS on PLGF protein in cocultures. Diphenyleneiodonium also blocked the effect of high flow to upregulate PLGF mRNA in isolated arterioles. Further studies identified NADPH oxidase 4 as a source of reactive oxygen species for this pathway. We conclude that FSS regulates PLGF expression via NADPH oxidase 4 and reactive oxygen species signaling.

Expression of placental growth factor in neonatal rat lungs after 85% hyperoxia exposure

Objective To investigate the expression of placental growth factor （PlGF） protein and mRNA in lungs of neonatal rats exposed to 85%hyperoxia, and to establish the relationship between PlGF and bronchopulmonary dysplasia （BPD）. Methods Forty-eight Sprague–Dawley neonatal rats were randomly exposed to air （control group）（n=24） and 85% hyperoxia （hyperoxia group）（n=24）within 12 h after birth. The rats were sacrificed at 3, 5 and 7 days after exposure （eight at each time） and their lungs were sampled. PlGF protein and mRNA expression in the lungs were determined by Western blot and real-time polymerase chain reaction （PCR） at 3, 5 and 7 days. Left lung tissue was used for morphological and histological observation with hematoxylin and eosin staining. Terminal air spaces and the secondary septa were counted manually under microscope. T-test was applied for statistics. Results Compared with the control group, morphological and histological analysis in the hyperoxia group revealed inflammatory cell infiltration,＆amp;nbsp;simplified alveolar structure, less alveolar, alveolar cavity expansion and thickened alveolar septum. Morphometric measurements showed that terminal air spaces and secondary septa were significantly fewer in the hyperoxia rats than those in the control group at 5 and 7 days （terminal air spaces：23.6±8.2 vs 33.1±6.2 and 28.5±9.2 vs 38.4±10.1, t=1.91, 2.53, all P〈0.05;secondary septa：56.0±12.2 vs 78.3±8.2 and 75.4±12.2 vs 126.1±10.2, t=2.14, 2.72, all P〈0.05）. Real-time PCR showed that expression of PlGF mRNA increased significantly on day 3, 5 and 7 in the hyperoxia group compared with the control group （1.16±0.17, 1.34±0.15 and 1.65±0.19 vs 0.65±0.21, 0.47±0.11 and 0.46±0.17, respectively, t=1.93, 2.55, 2.79, all P〈0.05）. Western blot also showed that expression of PlGF protein on day 3, 5 and 7 in the hyperoxia group increased compared with the control group, but only being significant on day 3 （0.24±0.17 vs 0.09±0.01, t=2.44, P〈0.05）. Conclusions Hyperoxia （85%） exposure could increase PlGF protein and mRNA expression in the lungs of neonatal rats, likely contributing to pathogenesis of BPD, and might lead to pulmonary vascular developmental disorders in BPD. Key words: Hyperoxia; Bronchopulmonary dysplasia; Pregnancy proteins

Edaravone inhibits hypoxia-induced trophoblast-soluble Fms-like tyrosine kinase 1 expression: A possible therapeutic approach to preeclampsia

ObjectiveTo investigate the effects of edaravone, a potent free radical scavenger used clinically, on hypoxia-induced trophoblast-soluble Fms-like tyrosine kinase 1 (sFlt-1) expression. MethodsA trophoblast cell line (HRT-8/SVneo) impaired by cobalt chloride (CoCl2) was used as the cell model under hypoxic conditions. 3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyl tetrazolium bromide (MTT) was used to measure the viability of cells exposed to CoCl2 and edaravone. The levels of intracellular reactive oxygen species (ROS) were analyzed by flow cytometry. mRNA expression of sFlt-1, vascular endothelial growth factor (VEGF), and placental growth factor (PlGF) in trophoblasts was measured by real-time polymerase chain reaction, and the secretion of sFlt-1, VEGF, and PlGF proteins was analyzed by enzyme-linked immunosorbent assays (ELISAs). A human umbilical vein endothelial cell (HUVEC) tube-formation assay was performed to identify the effects of CoCl2 and edaravone on vascular development. ResultsCoCl2 treatment caused the loss of trophoblast viability, the formation of ROS, and sFlt-1 mRNA and protein expression in a dose-dependent manner. Pretreatment with edaravone significantly inhibited hypoxia-induced oxidative stress formation and sFlt-1 expression in trophoblasts. Neither PlGF nor VEGF mRNA or protein expression was increased by CoCl2. In the in vitro tube formation assay, edaravone showed a protective role in vascular development under hypoxic conditions. ConclusionThis study demonstrated that hypoxia leading to increased sFlt-1 release in trophoblasts may contribute to the placental vascular formation abnormalities observed in preeclampsia and suggested that the free radical scavenger edaravone could be a candidate for the effective treatment of preeclampsia.

Aldosterone Promotes Vascular Remodeling by Direct Effects on Smooth Muscle Cell Mineralocorticoid Receptors

Vascular remodeling occurs after endothelial injury, resulting in smooth muscle cell (SMC) proliferation and vascular fibrosis. We previously demonstrated that the blood pressure-regulating hormone aldosterone enhances vascular remodeling in mice at sites of endothelial injury in a placental growth factor-dependent manner. We now test the hypothesis that SMC mineralocorticoid receptors (MRs) directly mediate the remodeling effects of aldosterone and further explore the mechanism. A wire-induced carotid injury model was performed in wild-type mice and mice with inducible SMC-specific deletion of the MR. Aldosterone did not affect re-endothelialization after injury in wild-type mice. Deletion of SMC-MR prevented the 79% increase in SMC proliferation induced by aldosterone after injury in MR-Intact littermates. Moreover, both injury-induced and aldosterone-enhanced vascular fibrosis were attenuated in SMC-specific MR knockout mice. Further exploration of the mechanism revealed that aldosterone-induced vascular remodeling is prevented by in vivo blockade of the placental growth factor-specific receptor, type 1 vascular endothelial growth factor receptor (VEGFR1), the receptor for placental growth factor. Immunohistochemistry of carotid vessels shows that the induction of VEGFR1 expression in SMC after vascular injury is attenuated by 72% in SMC-specific MR knockout mice. Moreover, aldosterone induction of vascular placental growth factor mRNA expression and protein release are also prevented in vessels lacking SMC-MR. These studies reveal that SMC-MR is necessary for aldosterone-induced vascular remodeling independent of renal effects on blood pressure. SMC-MR contributes to induction of SMC VEGFR1 in the area of vascular injury and to aldosterone-enhanced vascular placental growth factor expression and hence the detrimental effects of aldosterone are prevented by VEGFR1 blockade. This study supports exploring MR antagonists and VEGFR1 blockade to prevent pathological vascular remodeling induced by aldosterone.

Increased expression of placental growth factor in high-grade endometrial carcinoma

Placental growth factor (PlGF), a homolog of vascular endothelial growth factor (VEGF), exerts pleiotropic functions in cancer by affecting tumor cells as well as endothelial and inflammatory cells. Moreover, PlGF expression correlates with tumor stage, recurrence, metastasis and patient outcome in different types of cancer. Recently, administration of anti-PlGF therapy reduced tumor growth and metastasis in preclinical tumor models. In the present study, we evaluated the diagnostic and prognostic value of systemic and local expression of PlGF in primary endometrial carcinomas. PlGF levels in tumor lysates (n=128) and serum (n=88) of patients with primary endometrial cancer were determined using ELISA. PlGF mRNA expression in endometrial carcinoma tissues was quantified by quantitative qRT-PCR. Results were compared to endometrial cancer stage and grade. Systemic PlGF levels were not altered in patients with endometrial cancer (FIGO stage I-II-III) as compared to healthy controls. Only in FIGO stage IV patients, serum PlGF levels were slightly increased. Local PlGF mRNA and protein expression in endometrial tumors progressively increased with tumor grade. In endometrioid carcinomas, PlGF mRNA expression was significantly increased in endometrioid grade 3 tumors as compared to normal endometrial tissue. PlGF protein expression was significantly increased in endometrioid grade 2 and 3 carcinomas and in serous carcinomas as compared to normal endometrial tissue. Our study showed that systemic/serum PlGF levels cannot be used as a diagnostic or prognostic marker in endometrial cancer. However, the increased local expression of PlGF, primarily in high-grade carcinomas, underscores the possibility for preclinical assessment of anti-PlGF therapy in endometrial cancer.

Thrombin enhances soluble Fms-like tyrosine kinase 1 expression in trophoblasts; possible involvement in the pathogenesis of preeclampsia

To investigate the possible impact of thrombin on soluble Fms-like tyrosine kinase 1 (sFlt-1) expression in trophoblasts. Experimental. University hospital laboratory. A trophoblast cell line (HRT-8/SVneo) was treated with thrombin, protease-activated receptor 1 (PAR-1)-specific agonist SFLLERN, and thrombin antagonist PPACK. mRNA expression of sFlt-1, vascular endothelial growth factor (VEGF), and placental growth factor (PlGF) in trophoblasts, with the use of real-time polymerase chain reaction; and the secretion of sFlt-1, VEGF, and PlGF protein from trophoblasts, with the use of ELISA. Administration of thrombin (10 U/mL) and PAR-1-specific agonist SFLLRN (300 μmol/L) increased sFlt-1 mRNA expression (4.24 ± 0.74- and 4.21 ± 0.79-fold, respectively) and protein secretion (5.08 ± 0.42- and 1.89 ± 0.16-fold, respectively) in HRT-8/SVneo. The induction of sFlt-1 protein secretion by thrombin was dose dependent. The effect of thrombin was completely reduced by thrombin inhibitor PPACK. Thrombin increased mRNA expression of VEGF but did not change VEGF secretion and PlGF mRNA expression and secretion. During placental development, thrombin, generated in the local hemorrhage of the uteroplacenta increases trophoblast expression of sFlt-1. Consequently, thrombin may contribute to the pathogenesis of preeclampsia.

Expression of placental growth factor in regenerating livers after partial hepatectomy in the rat

Placental growth factor (PlGF) is known for its role in pathological conditions to protect parenchymal cells of different organs from injury, whereas its presence in the liver and its potential importance in stimulating liver regeneration has never been described. This was investigated in this study using a rat model of partial hepatectomy (PH). The rat model of 70, 80, and 90% PH was used. Liver samples were taken peroperatively, 1 h, 1, 2, 3, and 7 days after surgery. Liver regeneration was evaluated by liver weight/body weight ratio, liver regeneration rate (%), and proliferating cell marker Ki67. The expression of PlGF, vascular endothelial growth factor (VEGF), VEGF receptor 1 (Flt-1), VEGF receptor 2 (Flk-1), and hypoxia inducible factor-1α mRNA was measured by quantitative real-time PCR and localized by immunohistochemistry. The mRNA expression of PlGF was upregulated immediately after PH. Compared with 70 and 80% PH groups, the 90% PH group had a significantly lower PlGF and hypoxia inducible factor-1α mRNA expression, in parallel to a delayed liver weight/body weight ratio recovery. Only little differences were observed in VEGF, Flt-1, and Flk-1 mRNA expression among the PH groups. This study shows for the first time the PlGF upregulation in regenerating livers, which is related to hypoxia stimulation and liver growth. The swift PlGF upregulation immediately after PH may indicate an important role for the PlGF/Flt-1 pathway in the early stage of liver regeneration.

Expression and prognostic significance of placental growth factor in hepatocellular carcinoma and peritumoral liver tissue

Vascular endothelial growth factor-targeted therapy is a promising treatment for hepatocellular carcinoma (HCC), but its clinical benefit is often accompanied by acquired resistance. In animal studies, antiplacental growth factor therapy is effective with less resistance. The role of placental growth factor (PlGF) in the progression of HCC is not clear. In our study, we used immunohistochemistry in tissue microarrays to investigate PlGF expression in tumor and peritumoral liver tissues from 105 patients with HCC. Intratumoral and peritumoral PlGF mRNA expression was analyzed in another cohort of 37 patients. Peritumoral PlGF expression was significantly higher than intratumoral PlGF expression (p < 0.001). Intratumoral PlGF expression was not associated with patients' overall survival (OS) or time to recurrence (TTR). However, peritumoral PlGF expression, which was associated with tumor size, presence of intrahepatic metastasis, TNM stage and Barcelona Clinic Liver Cancer stage, was an independent risk factor for OS (p = 0.026) and TTR (p = 0.041). The prognostic value of peritumoral PlGF expression was further validated in a validation cohort (n = 394). We inferred that the elevation of PlGF in peritumoral liver might be induced by hypoxia. We found that peritumoral PlGF expression was associated with hypoxia-inducible factor-1α (p = 0.017). PlGF expression was elevated in L02, a hepatic cell line, under hypoxic conditions in vitro. These findings indicate that high peritumoral PlGF expression is associated with tumor recurrence and survival after resection of HCC. PlGF could be a target of adjuvant therapy and deserves further investigations.

Angiotensin II upregulates the expression of placental growth factor in human vascular endothelial cells and smooth muscle cells

BackgroundAtherosclerosis is now recognized as a chronic inflammatory disease. Angiotensin II (Ang II) is a critical factor in inflammatory responses, which promotes the pathogenesis of atherosclerosis. Placental growth factor (PlGF) is a member of the vascular endothelial growth factor (VEGF) family cytokines and is associated with inflammatory progress of atherosclerosis. However, the potential link between PlGF and Ang II has not been investigated. In the current study, whether Ang II could regulate PlGF expression, and the effect of PlGF on cell proliferation, was investigated in human vascular endothelial cells (VECs) and smooth muscle cells (VSMCs).ResultsIn growth-arrested human VECs and VSMCs, Ang II induced PlGF mRNA expression after 4 hour treatment, and peaked at 24 hours. 10-6 mol/L Ang II increased PlGF protein production after 8 hour treatment, and peaked at 24 hours. Stimulation with Ang II also induced mRNA expression of VEGF receptor-1 and -2(VEGFR-1 and -2) in these cells. The Ang II type I receptor (AT1R) antagonist blocked Ang II-induced PlGF gene expression and protein production. Several intracellular signals elicited by Ang II were involved in PlGF synthesis, including activation of protein kinase C, extracellular signal-regulated kinase 1/2 (ERK1/2) and PI3-kinase. A neutralizing antibody against PlGF partially inhibited the Ang II-induced proliferation of VECs and VSMCs. However, this antibody showed little effect on the basal proliferation in these cells, whereas blocking antibody of VEGF could suppress both basal and Ang II-induced proliferation in VECs and VSMCs.ConclusionOur results showed for the first time that Ang II could induce the gene expression and protein production of PlGF in VECs and VSMCs, which might play an important role in the pathogenesis of vascular inflammation and atherosclerosis.

Hydrogen Peroxide Upregulates PLGF and VEGF‐A Expression in Primary Human Coronary Artery Smooth Muscle Cells

When supply arteries become occluded a compensatory mechanism termed arteriogenesis occurs, resulting in collateral artery enlargement. Arteriogenesis involves attachment of monocytes to the endothelium and subsequent vessel wall infiltration. Placental growth factor (PLGF) mediates components of this collateral remodeling process. Our lab previously showed that hydrogen peroxide (H2O2) significantly upregulates PLGF mRNA expression in A10 cells, an established smooth muscle cell (SMC) line derived from rat aorta. Since SMC undergo phenotypic changes in culture, the goal of this study was to determine whether PLGF is also regulated by H2O2 in a more physiological model (primary SMC). Primary human coronary artery SMC (CASMC, Lonza) were grown to ~80% confluence, then serum‐starved (1% FBS) for 48 hrs. CASMC were then treated with exogenous H2O2 (50 μM) (N=3) for 4 hrs. PLGF and VEGF‐A gene expression was analyzed by real time quantitative PCR (Q‐PCR). PLGF gene expression was increased ~3.5 fold (p&lt;0.05) in CASMC by H2O2 treatment, compared with untreated CASMC (N=3). VEGF gene expression increased ~6 fold (p&lt;0.05) in response to H2O2. We conclude that H2O2 regulates PLGF and VEGF expression in primary SMC, confirming the physiological relevance of this mechanism. Further experiments to characterize protein levels of PLGF, VEGF, and PLGF/VEGF dimeric forms are underway. Support: NIH R01 HL‐084494 (PL).