ANXA5 Research Articles

P-058: Antiphospholipid antibodies and M2 haplotype in annexin A5 gene: possible relationship and clinical impact on feto-maternal outcome

P-058: Antiphospholipid antibodies and M2 haplotype in annexin A5 gene: possible relationship and clinical impact on feto-maternal outcome

Annexin-A5 organized in 2D-network at the plasmalemma eases human trophoblast fusion

Only a limited number of human cells can fuse to form a multinucleated syncytium. Cell fusion occurs as part of the differentiation of some cell types, including myotubes in muscle and osteoclasts in remodeling bone. In the differentiation of the human placenta, mononuclear cytotrophoblasts aggregate and fuse to form endocrinologically active, non-proliferative, multinucleated syncytia. These syncytia allow the exchange of nutrients and gases between the maternal and fetal circulation. Alteration of syncytial formation during pregnancy affects fetal growth and the outcome of the pregnancy. Here, we demonstrate the role of annexin A5 (AnxA5) in syncytial formation by cellular delivery of recombinant AnxA5 and RNA interference. By a variety of co-immunoprecipitation, immunolocalization and proximity experiments, we show that a pool of AnxA5 organizes at the inner-leaflet of the plasma membrane in the vicinity of a molecular complex that includes E-Cadherin, α-Catenin and β-Catenin, three proteins previously shown to form adherens junctions implicated in cell fusion. A combination of knockdown and reconstitution experiments with AnxA5, with or without the ability to self-assemble in 2D-arrays, demonstrate that this AnxA5 2D-network mediates E-Cadherin mobility in the plasmalemma that triggers human trophoblasts aggregation and thereby cell fusion.

Annexin A5 in treated hypertensive patients and its association with target organ damage.

Annexin A5 (AnxA5) has been previously linked to the presence of carotid and cardiac target organ damage (TOD) in the context of heart failure and rheumatologic patients. However, information is scant in the context of hypertension. Aim of our study was to evaluate AnxA5 in treated hypertension patients compared with normotensive controls and to determine whether it is associated with vascular and heart TOD evaluated as arterial stiffness, carotid plaque and left ventricular hypertrophy. We enrolled 123 consecutive treated hypertension and 124 normotensive controls. TOD was evaluated as pulse wave velocity (PWV, complior), left ventricular hypertrophy (echocardiography) and intima-media thickness and carotid plaque presence (ecographic methods). AnxA5 levels was dosed and compared in patients with and without hypertension and with and without TOD. With similar age hypertension patients showed higher SBP, DBP and AnxA5 levels (13.9 ± 11.1 vs 10.1 ± 8.4 ng/ml, P < 0.001) compared with controls. Regarding TOD hypertension showed higher PWV (8.5 ± 1.8 vs 7.6 ± 1.5 m/s, P < 0.001) and LVMI (121.7 ± 29.3 vs 113.5 ± 21.1 g/m, P < 0.05), whereas carotid intima-media thickness was superimposable. AnxA5 correlates with PWV (r = 0.13, P < 0.05) and DBP (r = 0.15, P < 0.01), whereas it has never been found as a significant independent predictor of TOD in linear regression analysis. Our data have shown that AnxA5 levels are increased in treated hypertension patients. In this condition, it is probably released in the plasma as a defensive mechanism through its anti-inflammatory and anticoagulants effects. We found a significant association with arterial stiffness, but AnxA5 was not found to be a significant predictor of TOD.

Anxa5 mediates the in vitro malignant behaviours of murine hepatocarcinoma Hca-F cells with high lymph node metastasis potential preferentially via ERK2/p-ERK2/c-Jun/p-c-Jun(Ser73) and E-cadherin.

Annexin A5 (Anxa5) is associated with the progression of some cancers, while its role and regulation mechanism in tumor lymphatic metastasis is rarely reported. This study aims to investigate the influence of Anxa5 knockdown on the malignant behaviours of murine hepatocarcinoma Hca-F cell line with high lymph node metastatic (LNM) potential and the underlying regulation mechanism. RNA interfering was performed to silence Anxa5 in Hca-F. Monoclonal shRNA-Anxa5- Hca-F cells were obtained via G418 screening by limited dilution method. Quantitative real-time RT-PCR (qRT-PCR) and Western blotting (WB) were applied to measure Anxa5 expression levels. CCK-8, Boyden transwell-chamber and in situ LN adhesion assays were performed to explore the effects of Anxa5 on the proliferation, migration, invasion and adhesion capacities of Hca-F. WB and qRT-PCR were used to detect the level changes of key molecules in corresponding signal pathways. We obtained two monoclonal shRNA-Anxa5-transfected Hca-F cell lines with stable knockdowns of Anxa5. Anxa5 knockdown resulted in significantly reduced proliferation, migration, invasion and in situ LN adhesion potentials of Hca-F in proportion to its knockdown extent. Anxa5 downregulation enhanced E-cadherin levels in Hca-F. Moreover, Anxa5 affected Hca-F behaviours specifically via ERK2/p-ERK2/c-Jun/p-c-Jun(Ser73) instead of p38MAPK/c-Jun, Jnk/c-Jun and AKT/c-Jun pathways. Anxa5 mediates the in vitro malignant behaviours of murine hepatocarcinoma Hca-F cells via ERK2/c-Jun/p-c-Jun(Ser73) and ERK2/E-cadherin pathways. It is an important molecule in metastasis (especially LNM) and a potential therapeutic target for hepatocarcinoma.

The changes in expression of high-sensitivity C-reactive protein, glutathione S-transferase Pi and annexin A5 in elderly patients with old myocardial infarction and the clinical significance

Objective To study the changes in expression of high-sensitivity C-reactive protein(hs-CRP), glutathione S-transferase Pi(GSTPi)and annexin A5(AnxA5)in elderly patients with old myocardial infarction and the clinical significance. Methods Serum levels of GSTPi and AnxA5 were measured by ELISA and the level of hs-CRP was measured by immunoturbidimetry in elderly patients with old myocardial infarction(n=185)from December 2012 to November 2015. Results Along with the increasing coronary artery stenosis, GSTPi level was decreased and AnxA5/hs-CRP levels were increased in elderly patients with old myocardial infarction.In comparison between coronary artery stenosis >95% group versus stenosis of 55%-65% group, GSTPi was(190.0±37.0)μg/L vs.(289.0±86.0)μg/L, AnxA5 was(33.9±4.0)μg/L vs.(8.1±2.9)μg/L, and hs-CRP was(15.3±1.3)mg/L vs.(5.9±0.8)mg/L with statistically significant differences(all P<0.01). There were significant differences between LVEF 30% group〔GSTPi(198.0±39.0)μg/L, AnxA5(38.9±5.1)μg/L and hs-CRP(17.9±1.9)mg/L〕and LVEF 40%-54% group〔GSTPi(219.0±61.0)μg/L, AnxA5(12.9±3.9)μg/L and hs-CRP(10.1±1.0)mg/L〕(all P<0.01). There were significant differences between NYHA Ⅳ group〔GSTPi(171.0±43.0)μg/L, AnxA5(18.1±5.0)μg/L and hs-CRP(16.9±2.1)mg/L〕and NYHAⅠgroup〔GSTPi(295.0±91.0)μg/L, AnxA5(7.3±3.1)μg/L and hs-CRP(7.8±1.3)mg/L〕(all P<0.01). Conclusions The expression of GSTPi, AnxA5 and hs-CRP in elderly patients with old myocardial infarction may become the new indicators to forecast the degrees of coronary artery stenosis and heart failure. Key words: Glutathione S-transferase pi; Annexin A5; C-reactive protein; Myocardial infarction

Concomitant measurements of serum annexin A5 levels and hematological indices as markers in recent and old myocardial infarction with low ejection fraction: A preliminary study

BackgroundSerum annexin A5 (anxA5) level is significantly increased in patients with acute coronary syndrome. Hematological indices are significantly increased in patients with ischemic heart disease. This study aimed to demonstrate the changes in the distribution of blood cells and the levels of anxA5 in patients presented with significant low ejection fraction ST-elevation acute myocardial infarction (STEMI) in comparison with corresponding patients with ischemic heart disease. MethodsPatients with low ejection fraction presenting at Hospital of Diyala University of Iraq were enrolled. Electrocardiograph (ECG), echocardiograph, hematological indices, serum annexin V (anxV) levels and the determinants of the cardio-metabolic risk factors were performed. Based on clinical examination, ECG findings and laboratory tests, patients were divided into healthy subjects (n=20); patients with acute MI (n=40) and with chronic MI (n=12). ResultsAcute MI has significant high levels of serum triglyceride, uric acid and high mean value of red cell distribution width (RDW) compared with healthy subjects and chronic MI. Platelet distribution width (PDW) is significantly reduced in patients of acute MI and chronic MI compared with healthy subjects, whereas the plateletcrit (PCT) is significantly higher in acute MI compared with healthy subjects. There is an insignificant difference between the means of serum anxA5 levels of acute MI (35.6±7.2ng/ml) and chronic MI (32.4±8.9ng/ml), but significantly higher than the cutoff level of the healthy subjects (5ng/ml). ConclusionsMeasurement of serum annexin level is a useful diagnostic marker of acute or chronic MI with low ejection fraction.

More than just innate affairs – on the role of annexins in adaptive immunity

In more than 30 years of research annexins have been demonstrated to regulate immune responses. The prototype member of this family, annexin (Anx) A1, has been widely recognized as an anti-inflammatory mediator affecting migration and cellular responses of various cell types of the innate immune system. Evidently, effects on innate immune cells also impact on the course of adaptive immune responses. Innate immune cells provide a distinct cytokine milieu during initiation of adaptive immunity which regulates the development of T cell responses. Moreover, innate immune cells such as monocytes can differentiate into dendritic cells and take an active part in T cell stimulation. Accumulating evidence shows a direct role for annexins in adaptive immunity. Anx A1, the annexin protein studied in most detail, has been shown to influence antigen presentation as well as T cells directly. Moreover, immune modulatory roles have been described for several other annexins such as Anx A2, Anx A4, Anx A5 and Anx A13. This review will focus on the involvement of Anx A1 and other annexins in central aspects of adaptive immunity, such as recruitment and activation of antigen presenting cells, T cell differentiation and the anti-inflammatory removal of apoptotic cells.

Functional characterization of annexin A5 gene promoter allelic variants

BackgroundM1 and M2 haplotypes are defined by 4 consecutive allelic variants in regulatory regions of the annexin A5 gene and have been found to reduce promoter activity. To date, no research has been carried out to investigate differential and individual impact each of the allelic variants has on promoter activity. In the current study, we functionally characterized the M1 and M2 haplotype allelic variants (c.-467G>A, c.-448A>C, c.-422T>C, c.-373G>A). We also characterized two other allelic variants located in the same regulatory region (c.-628C>T, c.-302T>G). Materials and methodsTheir impact on the ANXA5 promoter activity was examined using a luciferase reporter assay in BeWo cells. Electrophoretic mobility shift assay with probes centered around each polymorphism was used to examine the binding ability of the allelic variants to nuclear proteins from BeWo cells. ResultsOnly the c.-467G>A and c.-628C>T allelic variants influenced the activity of the ANXA5 promoter, as measured by luciferase activity. Differential specific interactions with nuclear proteins were obtained for all allelic variants, except for the c.-302T>G, indicating that these polymorphisms could have an impact on the ANXA5 expression. ConclusionsWe have functionally characterized allelic variants in the ANXA5 promoter, both alone and in combinations, and the results suggest that combinations of several individual variants contribute to modulate the ANXA5 transcriptional activity, most likely through binding of nuclear factors. These results provide new knowledge and insight into the mechanisms underlying the regulation of annexin A5 levels in healthy controls.

Annexin A5 haplotype M2 is not a risk factor for recurrent spontaneous abortion in Northern Europe: is there sufficient evidence?

The M2 haplotype of the annexin A5 gene is a well-recognized predisposition factor for recurrent spontaneous abortion (RSA). A recent publication by Nagirnaja et al. (2015) in PLoS One discusses the risk role of the M2 haplotype for RSA in cases compared with controls of North European extraction and arrives at a negative result. As a number of previous and fairly recent studies have supported the proposed involvement of the M2 haplotype in the cause of idiopathic RSA, this commentary aims to highlight problematic issues in the above publication. It is the opinion of the authors that the study by Nagirnaja et al. (2015) does not generate adequate proof of the absence of RSA risk, attributable to carriage of the M2 haplotype.

Cell Fusion Stage in Osteoclast Formation

Little is known about cell fusion that generates osteoclasts, multinucleated cells that resorb our bones in their continuous remodeling. Here we isolated fusion stage from preceding and subsequent stages of osteoclast formation and identified some proteins involved in this fusion process. To trigger osteoclastogenesis, we applied RANKL to RAW macrophage-like cells or M-CSF and RANKL to human monocytes. We blocked fusion by applying a reversible hemifusion inhibitor lysophosphatidylcholine, accumulated the ready-to-fuse macrophages for 16h and then removed our inhibitor. This fusion-synchronization approach has allowed us to concentrate within an hour cell fusion events that would normally develop within 16h. At the time of fusion, macrophages exposed at their surface phosphatidylserine (PS), lipid that is normally found only in the inner leaflet of the plasma membrane. CaCCinh-A01, an inhibitor of TMEM16 scramblases that mediate non-apoptotic PS externalization, suppressed both PS exposure at the surface of fusion-committed cells and synchronized fusion indicating the functional importance of PS externalization. We also found that fusion was suppressed by peptide inhibitors and antibodies to PS-binding proteins annexins A1 and A5 (AnxA1&A5) for RAW cells and AnxA5 for human monocytes. The importance of Anxs in osteoclast formation was further confirmed by finding that bone marrow cells from mice deficient in both AnxA1 and A5 have a lowered ability to generate osteoclasts. In addition to PS and Anxs, synchronized fusion involves endogenous retroviral human syncytin-1 protein that along with Anx A5 is present at the surface of fusion-committed human osteoclast precursors. We hypothesize that Anxs accumulated at TMEM16-externalized PS regulate activity of syncytin1-dependent fusion machinery.

Gene array of PDL cells exposed to Osteogain in combination with a bone grafting material.

The aim of the present study was to investigate the effects of Osteogain, a new formulation of enamel matrix derivative (EMD) in combination with a grafting material on a wide variety of genes for cytokines, transcription factors and extracellular matrix proteins involved in osteoblast differentiation. Primary human periodontal ligament (PDL) cells were seeded on natural bone mineral (NBM) particles coated with Osteogain for 24h and analyzed for regulated gene expression using a human osteogenesis gene super-array kit. Osteoblast-related genes include those transcribed during bone mineralization, ossification, bone metabolism, cell growth and differentiation as well as gene products representing extracellular matrix molecules, transcription factors and cell adhesion molecules. Osteogain significantly upregulated the expression of over 20 of the 100 genes examined including bone morphogenetic protein 2 (BMP2), TGFβ1, fibroblast growth factor (FGF), epidermal growth factor (EGF) and platelet-derived growth factor (PDGF) as well as some of their associated receptors. Osteogain also promoted gene expression of a number of osteoblast differentiation markers including collagen1α2 and alkaline phosphatase as well as cell adhesion molecules including fibronectin and a variety of integrin binding proteins. Interestingly, Osteogain promoted calcitonin receptor 55-fold and also promoted annexin A5 gene expression over 12-fold. The present study demonstrates that Osteogain is capable of either upregulating or downregulating the expression of a wide variety of genes including those for growth factors and cytokines when combined with a bone grafting material. The results from the present study demonstrate the large and potent effect of addition of Osteogain in combination to a bone grafting material over a wide variety of genes supporting osteogenesis.

Circulating annexin A5 predicts mortality in patients with heart failure.

Natriuretic peptides are currently used to predict mortality in patients with heart failure (HF). However, novel independent biomarkers are needed to improve risk stratification in these patients. We hypothesized that annexin A5 (anxA5) would be highly expressed by organs which are generally affected by HF and that circulating anxA5 levels would predict mortality in HF patients. We prospectively determined the diagnostic value of anxA5, N-terminal pro-B-type natriuretic peptide (NT-proBNP), C-reactive protein (CRP) and estimated glomerular filtration rate (eGFR) to predict mortality in 180 HF patients during a median follow-up of 3.6 years. Studies were conducted with anxA5(-/-) mice to investigate the underlying mechanisms. AnxA5 levels were significantly elevated in HF patients compared to healthy control subjects. Cox regression analysis demonstrated that anxA5, NT-proBNP and eGFR all predict mortality independently. AnxA5 significantly improved the diagnostic efficiency of NT-proBNP alone (improvement of c-statistic from 0.662 to 0.705, P < 0.001) and also combined with eGFR and CRP (improvement of c-statistic from 0.675 to 0.738, P < 0.001) to predict mortality in the Cox regression model. Receiver operating characteristic curve analysis showed that anxA5 predicted 3-year survival (area under curve 0.708) with an optimal cut-off value of 2.24 ng mL(-1) . Using anxA5(-/-) mice, we demonstrated that anxA5 is highly expressed in organs that are often affected by HF including lung, kidney, liver and spleen. Lysis of these organs in vitro resulted in a marked and significant increase in anxA5 concentrations. AnxA5 improves the diagnostic efficiency of conventional biomarkers to predict mortality in HF patients. Whereas natriuretic peptides originate from the myocardium, high circulating anxA5 levels in patients with HF are likely to reflect peripheral organ damage secondary to HF.

Examining the prevalence of non-criteria anti-phospholipid antibodies in patients with anti-phospholipid syndrome: a systematic review.

To systematically review and establish the prevalence of antibody positivity in assays not currently included in the APS classification criteria to detect antibodies directed against other phospholipids (PLs), PL binding proteins, coagulation factors and a mechanistic test for resistance of Annexin A5 (AnxA5) anticoagulant activity in APS and control populations. We searched PubMed and EMBASE using the key words APS, antiphospholipid antibodies, non-criteria, new assays, IgA anticardiolipin antibodies, lupus anticoagulant, anti-Domain I, IgA anti-β2-glycoprotein I antibodies, antiphosphatidylserine, anti-phosphatidylethanolamine, anti-phosphatidic acid, antiprothrombin, antiphosphatidylserine-prothtombin, anti-vimentin/cardiolipin complex and Annexin A5 resistance. Studies that met inclusion criteria to describe prevalence of non-criteria aPLs in APS patients (n > 10), disease and healthy control subjects were systematically examined. We selected 16 retrospective studies of 1404 APS patients, 1839 disease control and 797 healthy controls. The highest prevalence of non-criteria aPLs in the largest number of patients with APS was found in IgA anti-β2GPI studies (129/229, 56.3%), AnxA5R (87/163, 53.4%) and IgG anti-Domain I (241/548, 44.0%). Our finding of a significantly high prevalence of all non-criteria aPLs studied in patients with APS compared with controls was tempered by wide variation in sample size, retrospective collection, assay methodology and different determination of positivity. Therefore, prospective studies of sufficient size and appropriate methodology are required to evaluate the significance of these assays and their utility in the management of patients with APS.

Genetic variations in the annexin A5 gene and the risk of pregnancy‐related venous thrombosis

Annexin A5 is a natural anticoagulant assumed to have thrombomodulary functions as it shields phospholipid layers from coagulation complexes. It was recently shown that the M2 haplotype within the annexin A5 gene (ANXA5) promoter reduces the transcriptional activity of the gene. In a previous report, the M2 haplotype was found to be associated with pregnancy-related venous thrombosis (VT). To investigate whether the M1 or M2 haplotypes or other genetic variations in ANXA5 are associated with pregnancy-related VT. We investigated samples from 313 cases and 353 controls included in the VIP study, which is a case-control study of pregnancy-related VT. We analyzed tag single nucleotide polymorphisms (SNPs) selected from the CEU population (Utah Residents with Northern and Western European Ancestry) of HapMap and the M1 and the M2 haplotypes of the promoter. Odds ratios for VT were calculated for each haplotype with the wild type as the reference and for each tag SNP with the most common genotype as reference. We did not find any association between genetic variants in ANXA5 and the risk of pregnancy related VT, but some of the genetic variants were not in Hardy-Weinberg equilibrium. Neither the M1/M2 haplotypes nor the tag SNPs in ANXA5 were convincingly associated with pregnancy related VT, but other studies in this field are needed.

M2/ANXA5 haplotype as a predisposition factor in Malay women and couples experiencing recurrent spontaneous abortion: a pilot study

Recurrent spontaneous abortion (RSA) is a prevalent condition among the Malay population of Malaysia, where carriage risk of conventional hereditary thrombophilia factors has been generally ruled out. The contribution of M2/ANXA5, a common haplotype in the annexin A5 gene promoter, was evalauted for RSA in Malay. Seventy-seven women who had experienced two or more unexplained RSA and 41 available male partners were selected for study, with 360 population controls recruited from healthy Malay individuals. Incidence of M2 carriage and odds ratios were calculated between control and patient groups, and clinically defined subgroups and RSA risk was evaluated. M2/ANXA5, found in 42.2% of the general Malay population, was associated with greater risks for women with primary and secondary RSA with early (gestational week 5–15) losses. The risk was somewhat higher in Malay couples when both partners were carriers and a trend of higher prevalence was seen for the male partners patients who had experienced RSA. M2 carriage seems to be a risk factor with unusually high incidence in Malay women and couples with primary and secondary RSA with ‘early’ spontaneous abortions. The associated male partner risk confirms the proposed role of M2/ANXA5 as a genetic trait impeding embryonic anticoagulation.

Impaired osteoblast differentiation in annexin A2- and -A5-deficient cells.

Annexins are a class of calcium-binding proteins with diverse functions in the regulation of lipid rafts, inflammation, fibrinolysis, transcriptional programming and ion transport. Within bone, they are well-characterized as components of mineralizing matrix vesicles, although little else is known as to their function during osteogenesis. We employed shRNA to generate annexin A2 (AnxA2)- or annexin A5 (AnxA5)-knockdown pre-osteoblasts, and determined whether proliferation or osteogenic differentiation was altered in knockdown cells, compared to pSiren (Si) controls. We report that DNA content, a marker of proliferation, was significantly reduced in both AnxA2 and AnxA5 knockdown cells. Alkaline phosphatase expression and activity were also suppressed in AnxA2- or AnxA5-knockdown after 14 days of culture. The pattern of osteogenic gene expression was altered in knockdown cells, with Col1a1 expressed more rapidly in knock-down cells, compared to pSiren. In contrast, Runx2, Ibsp, and Bglap all revealed decreased expression after 14 days of culture. In both AnxA2- and AnxA5-knockdown, interleukin-induced STAT6 signaling was markedly attenuated compared to pSiren controls. These data suggest that AnxA2 and AnxA5 can influence bone formation via regulation of osteoprogenitor proliferation, differentiation, and responsiveness to cytokines in addition to their well-studied function in matrix vesicles.

AnxA5 reduces plaque inflammation of advanced atherosclerotic lesions in apoE(-/-) mice.

Annexin A5 (AnxA5) exerts anti-inflammatory, anticoagulant and anti-apoptotic effects through binding cell surface expressed phosphatidylserine. The actions of AnxA5 on atherosclerosis are incompletely understood. We investigated effects of exogenous AnxA5 on plaque morphology and phenotype of advanced atherosclerotic lesions in apoE−/− mice. Advanced atherosclerotic lesions were induced in 12 weeks old Western type diet fed apoE−/− mice using a collar placement around the carotid artery. After 5 weeks mice were injected either with AnxA5 (n = 8) or vehicle for another 4 weeks. AnxA5 reduced plaque macrophage content both in the intima (59% reduction, P < 0.05) and media (73% reduction, P < 0.01) of advanced atherosclerotic lesions of the carotid artery. These findings corroborated with advanced lesions of the aortic arch, where a 67% reduction in plaque macrophage content was observed with AnxA5 compared to controls (P < 0.01). AnxA5 did not change lesion extension, plaque apoptosis, collagen content, smooth muscle cell content or acellular plaque composition after 4 weeks of treatment as determined by immunohistochemistry in advanced carotid lesions. In vitro, AnxA5 exhibited anti-inflammatory effects in macrophages and a flow chamber based assay demonstrated that AnxA5 significantly inhibited capture, rolling, adhesion as well as transmigration of peripheral blood mononuclear cells on a TNF-α-activated endothelial cell layer. In conclusion, short-term treatment with AnxA5 reduces plaque inflammation of advanced lesions in apoE−/− mice likely through interfering with recruitment and activation of monocytes to the inflamed lesion site. Suppressing chronic inflammation by targeting exposed phosphatidylserine may become a viable strategy to treat patients suffering from advanced atherosclerosis.

Upregulation of annexin A5 affects the biological behaviors of lung squamous carcinoma cells in vitro

Annexin A5 is a Ca2+-dependent phospholipid-binding protein and protein kinase C inhibitory protein. It has a potential role in cellular signal transduction, inflammation, growth and differentiation. In this study, we evaluated the expression of this protein in lung tumor tissues and subsequently established a NCI-H520 cell line that stably expresses the wild-type ANXA5 gene to determine the effects of annexin A5 upregulation on the cell morphology, proliferation and metastasis potential in vitro. The effects of annexin A5 on NCI-H520 cells were tested by crystal violet staining, CCK-8 assay, scratch wound assay, and Transwell assay. The expressions of Akt, PCNA, vimentin, and E-cadherin were examined by Western blot assay. In this study, we demonstrated that annexin A5 is expressed at lower levels in tumor tissues compared with normal tissues. Additionally, the upregulation of this protein may inhibit the proliferation, migration, and invasion abilities of NCI-H520 cells in vitro. The transfected cells were arrested in the G1/S phase of the cell cycle, and the expression levels of Akt, PCNA and Vimentin were downregulated, while E-cadherin was upregulated.

Multicentre study of the clinical relevance of screening IVF patients for carrier status of the annexin A5 M2 haplotype

Thrombophilia and impaired placental vasculature are a major cause of adverse pregnancy outcome. In 2007, a new hereditary factor for obstetric complications and recurrent pregnancy loss (RPL) was identified as a sequence variation in the core promoter of the annexin A5 gene, ANXA5, called the M2 haplotype. M2 carriership has been demonstrated in couples with recurrent miscarriage and its origin is embryonic rather than specifically maternal, confirmed by subsequent papers. The M2 haplotype is the first report of a hereditary factor related to pregnancy pathology caused by embryonic-induced anticoagulation. It has been demonstrated that couples with RPL had equal and significantly increased M2 carriership and that maternal and paternal carriership confers equal risk. Given its importance for patients with RPL, and potentially implantation failure, this study assessed the incidence of carrier status for the M2 ANXA5 haplotype in both the male and female of couples attending five CARE IVF centres. In 314 patients (157 couples), 44% of couples (one or both partners), 24% of females, 26% of males and 37% of couples with unexplained infertility were M2 carriers. This high incidence has provoked further urgent studies on specific patient populations and on the value of post embryo-transfer therapy.

Improvement of Chloride Transport Defect by Gonadotropin-Releasing Hormone (GnRH) in Cystic Fibrosis Epithelial Cells

Cystic fibrosis (CF), the most common autosomal recessive disease in Caucasians, is due to mutations in the CFTR gene. F508del, the most frequent mutation in patients, impairs CFTR protein folding and biosynthesis. The F508del-CFTR protein is retained in the endoplasmic reticulum (ER) and its traffic to the plasma membrane is altered. Nevertheless, if it reaches the cell surface, it exhibits a Cl− channel function despite a short half-life. Pharmacological treatments may target the F508del-CFTR defect directly by binding to the mutant protein or indirectly by altering cellular proteostasis, and promote its plasma membrane targeting and stability. We previously showed that annexine A5 (AnxA5) directly binds to F508del-CFTR and, when overexpressed, promotes its membrane stability, leading to the restoration of some Cl− channel function in cells. Because Gonadotropin-Releasing Hormone (GnRH) increases AnxA5 expression in some cells, we tested it in CF cells. We showed that human epithelial cells express GnRH-receptors (GnRH-R) and that GnRH induces an AnxA5 overexpression and an increased Cl− channel function in F508del-CFTR cells, due to an increased stability of the protein in the membranes. Beside the numerous physiological implications of the GnRH-R expression in epithelial cells, we propose that a topical use of GnRH is a potential treatment in CF.