MMP-15 Is Upregulated in Preeclampsia, but Does Not Cleave Endoglin to Produce Soluble Endoglin

Preeclampsia is a major pregnancy complication, characterized by severe endothelial dysfunction, hypertension and maternal end-organ damage. Soluble endoglin is an anti-angiogenic protein released from placenta and thought to play a central role in causing the endothelial dysfunction and maternal organ injury seen in severe preeclampsia. We recently reported MMP-14 was the protease producing placentally-derived soluble endoglin by cleaving full-length endoglin present on the syncytiotrophoblast surface. This find identifies a specific drug target for severe preeclampsia; interfering with MMP-14 mediated cleavage of endoglin could decrease soluble endoglin production, ameliorating clinical disease. However, experimental MMP-14 inhibition alone only partially repressed soluble endoglin production, implying other proteases might have a role in producing soluble endoglin. Here we investigated whether MMP-15–phylogenetically the closest MMP relative to MMP-14 with 66% sequence similarity–also cleaves endoglin to produce soluble endoglin. MMP-15 was localized to the syncytiotrophoblast layer of the placenta, the same site where endoglin was localized. Interestingly, it was significantly (p = 0.03) up-regulated in placentas from severe early-onset preeclamptic pregnancies (n = 8) compared to gestationally matched preterm controls (n = 8). However, siRNA knockdown of MMP-15 yielded no significant decrease of soluble endoglin production from either HUVECs or syncytialised BeWo cells in vitro. Importantly, concurrent siRNA knockdown of both MMP-14 and MMP-15 in HUVECS did not yield further decrease in soluble endoglin production compared to MMP-14 siRNA alone. We conclude MMP-15 is up-regulated in preeclampsia, but does not cleave endoglin to produce soluble endoglin

Influence of surgical resection no plasma Endoglin (CD105) level in non-small cell lung cancer patients

Background and Aim: Endoglin is a proliferation-associated antigen on endothelial cells and essential for angiogenesis. Soluble endoglin (s‑endoglin), formed by proteolytic cleavage of ectodomain of membrane receptor could be an indicator of tumor‑activated endothelium. The aim of present study was to analyze changes of s‑endoglin level in plasma of lung cancer patients following surgical resection and to estimate the correlation of s‑endoglin with other soluble receptors, sTie2 and sVEGF R1. Patients and Methods: The study group consisted of 37 patients with stage I of non-small cell lung cancer. Plasma concentrations of s‑endoglin, sTie2 and sVEGF R1 were evaluated by ELISA, three times: before surgical resection and on postoperative day 7 and 30. Results: The median of s‑endoglin concentration decreased significantly on postoperative day 7 when compared with preoperative level and next increased on 30th day and it was comparable with that before surgery. s-Endoglin correlated with another soluble receptors, with sTie2 both before surgery (r=0.44) and on postoperative day 7 (r=0.52) and on 30th day (r=0.58), with sVEGF R1 — only on postoperative day 7 (r=0.75). Conclusion: The increased level of serum endoglin in lung cancer patients compared to controls and its changes after surgical treatment suggest potential application of soluble form of endoglin as potential tumor marker

Correlation of serum soluble endoglin to the severity of pre-eclampsia and its effect on the pregnancy outcome

Background: Preeclampsia is a major obstetric problem and a significant source of maternal and neonatal morbidity and mortality. Preeclampsia  is associated with  increased  risks of  placental  abruption,  acute renal  failure,  cerebrovascular and  cardiovascular complications, disseminated intravascular  coagulation,  and  maternal death. Consequently, early diagnosis of preeclampsia and  close  observation are imperative. In these cases of preeclampsia, combination of Doppler flowmetry and circulating angiogenic factors levels are recorded. Stepan et al examined endoglin, a cell-surface co-receptor for transforming growth factor in patients with Doppler flow patterns of preeclampsia at 19-24 weeks. Soluble endoglin levels were elevated in second trimester pregnancies with abnormal uterine perfusion in women who experienced preeclampsia. The aim of this study was to test if there is correlation between the level of serum endoglin in pregnant women with severe preeclampsia to the maternal and fetal outcome.Methods: This study was conducted on a group of 90 pregnant women attended to the Antenatal clinic and selected from the preeclampsia unit of EL- Shatby Maternity University Hospital, The selected patients were subdivided in two groups. Group A (control group): 30 cases of normotensive pregnant ladies. Group B (case group): 60 cases of severe preeclamptic pregnant ladies. Routine investigations, maternal serum soluble endoglin and ultrasound results were analysed and compared for both groups.Results: Significant correlation was found between severe preeclampsia and high level soluble endoglin. Significant correlation was found between high level of soluble endoglin and the occurrence of IUGR among the severe preeclamptic patients. Positive correlation was found between serum level of soluble endoglin and uterine artery PI and uterine artery RI, the higher the serum level of soluble endoglin the higher the uterine artery pulsatility and resistance index. Significant correlation was found between high level of soluble endoglin and the occurrence of specific complications, the higher the level of soluble endoglin the higher the risk of exposure to preeclampsia complications as the occurrence of eclamptic fits, the development of HELLP syndrome, the admission to the ICU, the admission of the baby to the NICU, and the fetal death.Conclusions: From our study, it is evident that serum endoglin rises during  normal  as  well  as  preeclamptic  pregnancy  and that  the  rise  in  preeclampsia  is  much  higher, the rise in endoglin levels may  occur  as  early  as  the  first  trimester  in  pregnancies  which  later  develop  preeclampsia.   Hence, used alone or in combination with uterine artery Doppler flowmetry, the measurement of soluble serum endoglin has the potential for use as a predictive clinical test for preeclampsia risk assessment and could potentially improve the outcome of pregnancy

A lesson for cancer research : placental microarray gene analysis in preeclampsia

Tumor progression and pregnancy share many common features, such as immune tolerance and invasion. The invasion of trophoblasts in the placenta into the uterine wall is essential for fetal development, and is thus precisely regulated. Its deregulation has been implicated in preeclampsia, a leading cause for maternal and perinatal mortality and morbidity. Pathogenesis of preeclampsia remains to be defined. Microarray-based gene profiling has been widely used for identifying genes responsible for preeclampsia. In this review, we have summarized the recent data from the microarray studies with preeclamptic placentas. Despite the complex of gene signatures, suggestive of the heterogeneity of preeclampsia, these studies identified a number of differentially expressed genes associated with preeclampsia. Interestingly, most of them have been reported to be tightly involved in tumor progression. We have discussed these interesting genes and analyzed their potential molecular functions in preeclampsia, compared with their roles in malignancy development. Further investigations are warranted to explore the involvement in molecular network of each identified gene, which may provide not only novel strategies for prevention and therapy for preeclampsia but also a better understanding of cancer cells. The trophoblastic cells, with their capacity for proliferation and differentiation, apoptosis and survival, migration, angiogenesis and immune modulation by exploiting similar molecular pathways, make them a compelling model for cancer research

Serum proteome profiling identifies novel and powerful markers of cystic fibrosis liver disease.

Cystic Fibrosis associated liver disease (CFLD) develops in approximately 30% of CF patients. However, routine sensitive diagnostic tools for CFLD are lacking. Within this study, we aimed to identify new experimental biomarkers for the detection of CFLD. 45 CF patients were included in the study and received transient elastography. Differential regulation of 220 different serum proteins was assessed in a subgroup of patients with and without CFLD. Most interesting candidate proteins were further quantified and validated by ELISA in the whole patient cohort. To assess a potential relation of biomarker expression to the degree of hepatic fibrosis, serum biomarkers were further determined in 18 HCV patients where liver histology was available. 43 serum proteins differed at least 2-fold in patients with CFLD compared to those without liver disease as identified in proteome profiling. In ELISA quantifications, TIMP-4 and Endoglin were significantly up-regulated in patients with CFLD as diagnosed by clinical guidelines or increased liver stiffness. Pentraxin-3 was significantly decreased in patients with CFLD. Serum TIMP-4 and Endoglin showed highest values in HCV patients with liver cirrhosis compared to those with fibrosis but without cirrhosis. At a cut-off value of 6.3 kPa, transient elastography compassed a very high diagnostic accuracy and specificity for the detection of CFLD. Among the biomarkers, TIMP-4 and Endoglin exhibited a high diagnostic accuracy for CFLD. Diagnostic sensitivities and negative predictive values were increased when elastography and TIMP-4 and Endoglin were combined for the detection of CFLD. Serum TIMP-4 and Endoglin are increased in CFLD and their expression correlates with hepatic staging. Determination of TIMP-4 and Endoglin together with transient elastography can increase the sensitivity for the non-invasive diagnosis of CFLD

The roles of endoglin gene in cerebrovascular diseases.

Endoglin (ENG, also known as CD105) is a transforming growth factor β (TGFβ) associated receptor and is required for both vasculogenesis and angiogenesis. Angiogenesis is important in the development of cerebral vasculature and in the pathogenesis of cerebral vascular diseases. ENG is an essential component of the endothelial nitric oxide synthase activation complex. Animal studies showed that ENG deficiency impairs stroke recovery. ENG deficiency also impairs the regulation of vascular tone, which contributes to the pathogenesis of brain arteriovenous malformation (bAVM) and vasospasm. In human, functional haploinsufficiency of ENG gene causes type I hereditary hemorrhagic telangiectasia (HHT1), an autosomal dominant disorder. Compared to normal population, HHT1 patients have a higher prevalence of AVM in multiple organs including the brain. Vessels in bAVM are fragile and tend to rupture, causing hemorrhagic stroke. High prevalence of pulmonary AVM in HHT1 patients are associated with a higher incidence of paradoxical embolism in the cerebral circulation causing ischemic brain injury. Therefore, HHT1 patients are at risk for both hemorrhagic and ischemic stroke. This review summarizes the possible mechanism of ENG in the pathogenesis of cerebrovascular diseases in experimental animal models and in patients

Endoglin and squamous cell carcinomas

Despite the fact that the role of endoglin on endothelial cells has been extensively described, its expression and biological role on (epithelial) cancer cells is still debatable. Especially its function on squamous cell carcinoma (SCC) cells is largely unknown. Therefore, we investigated SCC endoglin expression and function in three types of SCCs; head and neck (HNSCC), esophageal (ESCC) and vulvar (VSCC) cancers. Endoglin expression was evaluated in tumor specimens and 14 patient-derived cell lines. Next to being expressed on angiogenic endothelial cells, endoglin is selectively expressed by individual SCC cells in tumor nests. Patient derived HNSCC, ESCC and VSCC cell lines express varying levels of endoglin with high interpatient variation. To assess the function of endoglin in signaling of TGF-β ligands, endoglin was overexpressed or knocked out or the signaling was blocked using TRC105, an endoglin neutralizing antibody. The endoglin ligand BMP-9 induced strong phosphorylation of SMAD1 independent of expression of the type-I receptor ALK1. Interestingly, we observed that endoglin overexpression leads to strongly increased soluble endoglin levels, which in turn decreases BMP-9 signaling. On the functional level, endoglin, both in a ligand dependent and independent manner, did not influence proliferation or migration of the SCC cells. In conclusion, these data show endoglin expression on individual cells in the tumor nests in SCCs and a role for (soluble) endoglin in paracrine signaling, without directly affecting proliferation or migration in an autocrine manner.</p

Modulation of endoglin expression in islets of langerhans by VEGF reveals a novel regulator of islet endothelial cell function

BACKGROUND: Endoglin/CD105 is an auxiliary receptor for transforming growth factor-β with established roles in vascular remodelling. It has recently been shown that heterozygous endoglin deficiency in mice decreases insulin secretion in an animal model of obesity, highlighting a potential role for endoglin in the regulation of islet function. We have previously identified two different populations of endoglin expressing cells in human and mouse islets which are: (i) endothelial cells (ECs) and (ii) islet mesenchymal stromal cells. The contribution of islet EC endoglin expression to islet development and sensitivity to VEGF is unknown and is the focus of this study. RESULTS: In vitro culture of mouse islets with VEGF164 for 48 h increased endoglin mRNA levels above untreated controls but VEGF did not modulate VEGFR2, CD31 or CD34 mRNA expression or islet viability. Removal of EC-endoglin expression in vivo reduced islet EC area but had no apparent effect on islet size or architecture. CONCLUSION: EC-specific endoglin expression in islets is sensitive to VEGF and plays partial roles in driving islet vascular development, however such regulation appears to be distinct to mechanisms required to modulate islet viability and size

Endoglin (CD105) expression in ovarian serous carcinoma effusions is related to chemotherapy status

Endoglin (CD105), a cell surface co-receptor for transforming growth factor-β, is expressed in proliferating endothelial cells, as well as in cancer cells. We studied endoglin expression and its clinical relevance in effusions, primary tumors, and solid metastatic lesions from women with advanced-stage ovarian serous carcinoma. Endoglin expression was analyzed by immunohistochemistry in effusions (n = 211; 174 peritoneal, 37 pleural). Cellular endoglin staining was analyzed for association with the concentration of soluble endoglin (previously determined by ELISA) in 95 corresponding effusions and analyzed for correlation with clinicopathologic parameters, including survival. Endoglin expression was additionally studied in 34 patient-matched primary tumors and solid metastases. Carcinoma and mesothelial cells expressed endoglin in 95/211 (45%) and 133/211 (63%) effusions, respectively. Carcinoma cell endoglin expression was more frequent in effusions from patients aged ≤60 years (p = 0.048) and in post- compared to prechemotherapy effusions (p = 0.014), whereas mesothelial cell endoglin expression was higher in prechemotherapy effusions (p = 0.021). No association was found between cellular endoglin expression and its soluble effusion concentration. Endoglin was expressed in 17/34 (50%) primary tumors and 19/34 (56%) metastases, with significantly higher percentage of immunostained cells in solid metastases compared to effusions (p = 0.036). Endoglin expression did not correlate with survival. Tumor cell endoglin expression is higher in post- vs. prechemotherapy effusions, whereas the opposite is seen in mesothelial cells. Together with its upregulation in solid metastases, this suggests that the expression and biological role of endoglin may differ between cell populations and change along tumor progression in ovarian carcinoma

Directional Next-Generation RNA Sequencing and Examination of Premature Termination Codon Mutations in Endoglin/Hereditary Haemorrhagic Telangiectasia

Hereditary haemorrhagic telangiectasia (HHT) is a disease characterised by abnormal vascular structures, and most commonly caused by mutations in ENG, ACVRL1 or SMAD4 encoding endothelial cell-expressed proteins involved in TGF-β superfamily signalling. The majority of mutations reported on the HHT mutation database are predicted to lead to stop codons, either due to frameshifts or direct nonsense substitutions. The proportion is higher for ENG (67%) and SMAD4 (65%) than for ACVRL1 (42%), p < 0.0001. Here, by focussing on ENG, we report why conventional views of these mutations may need to be revised. Of the 111 stop codon-generating ENG mutations, on ExPASy translation, all except one were premature termination codons (PTCs), sited at least 50-55 bp upstream of the final exon-exon boundary of the main endoglin isoform, L-endoglin. This strongly suggests that the mutated RNA species will undergo nonsense-mediated decay. We provide new in vitro expression data to support dominant negative activity of stable truncated endoglin proteins but suggest these will not generate HHT: the single natural stop codon mutation in L-endoglin (sited within 50-55 nucleotides of the final exon-exon boundary) is unlikely to generate functional protein since it replaces the entire transmembrane domain, as would 8 further natural stop codon mutations, if the minor S-endoglin isoform were implicated in HHT pathogenesis. Finally, next-generation RNA sequencing data of 7 different RNA libraries from primary human endothelial cells demonstrate that multiple intronic regions of ENG are transcribed. The potential consequences of heterozygous deletions or duplications of such regions are discussed. These data support the haploinsufficiency model for HHT pathogenesis, explain why final exon mutations have not been detected to date in HHT, emphasise the potential need for functional examination of non-PTC-generating mutations, and lead to proposals for an alternate stratification system of mutational types for HHT genotype-phenotype correlations