Elevated plasma level of soluble F11 receptor/junctional adhesion molecule-A (F11R/JAM-A) in hypertension

Serum protein responses to Dietary Approaches to Stop Hypertension (DASH) and DASH-Sodium trials and associations with blood pressure changes

OBJECTIVES

The Dietary Approaches to Stop Hypertension (DASH) diet reduces blood pressure, but the mechanisms underlying DASH diet-blood pressure relations are not well understood. Proteomic measures may provide insights into the pathophysiological mechanisms through which the DASH diet reduces blood pressure.

METHODS

The DASH (1994-1996) and DASH-Sodium (1997-1999) trials were multicenter, randomized-controlled feeding trials. Proteomic profiling was conducted in serum collected at the end of the feeding period (DASH, N = 215; DASH-Sodium, N = 390). Multivariable linear regression models were used to identify interactions between 71 DASH diet-related proteins and changes in systolic and diastolic blood pressure. Estimates were meta-analyzed across both trials. Elastic net models were used to identify proteins that predict changes in blood pressure.

RESULTS

Ten significant interactions were identified [systolic blood pressure: seven proteins; diastolic blood pressure: three proteins], which represented nine unique proteins. A high level of renin at the end of the feeding period was associated with greater reductions in diastolic blood pressure in individuals consuming the control than DASH diets. A high level of procollagen c-endopeptidase enhancer 1 (PCOLCE) and collagen triple helix repeat-containing protein 1 (CTHRC1) were associated with greater reductions in systolic blood pressure in individuals consuming the DASH than control diets, and with elevations in systolic blood pressure in individuals consuming the control diets (P for interaction for all tests < 0.05). Elastic net models identified six additional proteins that predicted change in blood pressure.

CONCLUSIONS

Several novel proteins were identified that may provide some insight into the relationship between the DASH diet and blood pressure.

Female and male obese Zucker rats display differential inflammatory mediator and long non-coding RNA profiles

AIMS

The goal of this study was to identify mediators in peri-lymphatic adipose tissue (PLAT) that are altered in obese versus lean Zucker rats, with focus on potential sex differences MAIN METHODS: Mesenteric PLAT was analyzed with protein and lncRNA arrays. Additional RT-PCR confirmation was performed with epididymal/ovarian fat.

KEY FINDINGS

MCP-1, TCK-1, Galectin-1, Galectin-3, and neuropilin-1 were elevated in PLAT from obese rats of both sexes. However, 11 additional proteins were elevated only in obese males while 24 different proteins were elevated in obese females. Profiling of lncRNAs revealed lean males have elevated levels of NEAT1, MALAT1 and GAS5 compared to lean females. NEAT1, MALAT1, and GAS5 were significantly reduced with obesity in males but not in females. Another lncRNA, HOTAIR, was higher in lean females compared to males, and its levels in females were reduced with obesity. Obese rats of both sexes had similar histologic findings of mesenteric macrophage crown-like structures and hepatocyte fat accumulation.

SIGNIFICANCE

While obese male and female Zucker rats both have increased inflammation, they have distinct signals. Future studies of the proteome and lncRNA landscape of obese males vs. females in various animal models and in human subjects are warranted to better guide development of therapeutics for obesity-induced inflammation.

Involvement of single nucleotide polymorphisms of junction adhesion molecule with small vessel vascular dementia

Objectives

It is now recognized that blood brain barrier (BBB) leakage occurs in cerebral small vascular disease (CSVD) and plays a significant role in the pathophysiology of vascular dementia. We hypothesized that genetic polymorphisms of junctional adhesion molecule-A (JAM-A) (which may result in compromised structure of tight junction proteins that form the BBB) in combination with cerebrovascular risk factors hypertension, lipid disorders, and type 2 diabetes may result in BBB leakage and increase the individual's risk of CSVD-related dementia.

Methods

In this case-control study, 97 controls with a mean Mini-Mental State Exam (MMSE) score of 29 and 38 CSVD-related vascular dementia participants (mean MMSE score of 19) were recruited. Bloods were collected for the analysis of two common single nucleotide polymorphisms (SNPs) of the JAM-A genotypes rs790056 and rs2481084 using real-time polymerase chain reaction (PCR) assay. Medical history of hypertension, hyperlipidemia, and diabetes was collected for all participants.

Results

Polymorphisms of genotype JAM-A SNP rs790056 showed statistically significant result when the subgroup with hyperlipidemia was analyzed (OR = 3.130, p = 0.042 for TC + CC genotypes with hyperlipidaemia vs controls). Similar result was found with diabetes (OR = 4.670, p = 0.031 for TC + CC genotypes vs controls). No significant result was found with hypertension. Borderline results of statistical significance were found for JAM-A SNP rs2481084 with hyperlipidemia (OR = 3.210, p = 0.054 for TC + CC genotypes vs controls) and with diabetes (OR = 3.620, p = 0.069 for TC + CC genotypes vs controls) but not for hypertension. The borderline results might have been due to lack of statistical power because of small sample size.

Conclusions

These results lend further support that cerebrovascular risk factors interact with genetic polymorphisms of BBB proteins to increase the risk of vascular dementia.

Relationship between the Soluble F11 Receptor and Annexin A5 in African Americans Patients with Type-2 Diabetes Mellitus

Type 2 diabetes mellitus (T2DM) is characterized by endothelial dysfunction, increased thrombogenicity, and inflammation. The soluble human F11 receptor (sF11R) and annexin A5 (ANXA5) play crucial roles in inflammatory thrombosis and atherosclerosis. We examined the relationship between circulating sF11R and ANXA5 and their impact on endothelial function. The study included 125 patients with T2DM. Plasma levels of sF11R and ANXA5 were quantified by ELISA. Microvascular function was assessed using the vascular reactivity index (VRI). Large artery stiffness was assessed by carotid-femoral pulse wave velocity (PWV). Carotid intima-media thickness (CIMT) was assessed by B-mode ultrasound imaging. The mean age of patients in the study was 59.7 ± 7.8 years, 78% had hypertension, 76% had dyslipidemia, and 12% had CKD. sF11R correlated positively with ANXA5 levels (β = 0.250, p = 0.005), and correlated inversely with VRI and total nitic oxide (NO), (β = −0.201, p = 0.024; β = −0.357, p = 0.0001, respectively). Multivariate regression analysis revealed that sF11R was independently associated with ANXA5 in the total population and in patients with HbA1c > 6.5% (β = 0.366, p = 0.007; β = 0.425, p = 0.0001, respectively). sF11R and ANXA5 were not associated with vascular outcome, suggesting that they may not be reliable markers of vascular dysfunction in diabetes. The clinical significance of sF11R/ANXA5 association in diabetes warrants further investigation in a larger population.

Homophilic Interaction Between Transmembrane-JAM-A and Soluble JAM-A Regulates Thrombo-Inflammation: Implications for Coronary Artery Disease

Genetic predisposition through F11R-single-nucleotide variation (SNV) influences circulatory soluble junctional adhesion molecule-A (sJAM-A) levels in coronary artery disease (CAD) patients. Homozygous carriers of the minor alleles (F11R-SNVs rs2774276, rs790056) show enhanced levels of thrombo-inflammatory sJAM-A. Both F11R-SNVs and sJAM-A are associated with worse prognosis for recurrent myocardial infarction in CAD patients. Platelet surface-associated JAM-A correlate with platelet activation markers in CAD patients. Activated platelets shed transmembrane-JAM-A, generating proinflammatory sJAM-A and JAM-A-bearing microparticles. Platelet transmembrane-JAM-A and sJAM-A as homophilic interaction partners exaggerate thrombotic and thrombo-inflammatory platelet monocyte interactions. Therapeutic strategies interfering with this homophilic interface may regulate thrombotic and thrombo-inflammatory platelet response in cardiovascular pathologies where circulatory sJAM-A levels are elevated.

Identification of Four Potential Biomarkers Associated With Coronary Artery Disease in Non-diabetic Patients by Gene Co-expression Network Analysis

Background

Coronary artery disease (CAD) is a type of cardiovascular disease that greatly hurts the health of human beings. Diabetic status is one of the largest clinical factors affecting CAD-associated gene expression changes. Most of the studies focus on diabetic patients, whereas few have been done for non-diabetic patients. Since the pathophysiological processes may vary among these patients, we cannot simply follow the standard based on the data from diabetic patients. Therefore, the prognostic and predictive diagnostic biomarkers for CAD in non-diabetic patient need to be fully recognized.

Materials and Methods

To screen out candidate genes associated with CAD in non-diabetic patients, weighted gene co-expression network analysis (WGCNA) was constructed to conduct an analysis of microarray expression profiling in patients with CAD. First, the microarray data GSE20680 and GSE20681 were downloaded from NCBI. We constructed co-expression modules via WGCNA after excluding the diabetic patients. As a result, 18 co-expression modules were screened out, including 1,225 differentially expressed genes (DEGs) that were obtained from 152 patients (luminal stenosis ≥50% in at least one major vessel) and 170 patients (stenosis of <50%). Subsequently, a Pearson's correlation analysis was conducted between the modules and clinical traits. Then, a functional enrichment analysis was conducted, and we used gene network analysis to reveal hub genes. Last, we validated the hub genes with peripheral blood samples in an independent patient cohort using RT-qPCR.

Results

The results showed that the midnight blue module and the yellow module played vital roles in the pathogenesis of CAD in non-diabetic patients. Additionally, CD40, F11R, TNRC18, and calcium/calmodulin-dependent protein kinase type II gamma (CAMK2G) were screened out and validated using enzyme-linked immunosorbent assay (ELISA) in an independent patient cohort and immunohistochemical (IHC) staining in an atherosclerosis mouse model.

Conclusion

Our findings demonstrate that hub genes, CD40, F11R, TNRC18, and CAMK2G, are surrogate diagnostic biomarkers and/or therapeutic targets for CAD in non-diabetic patients and require deeper validation.

Functional inhibition of F11 receptor (F11R/junctional adhesion molecule-A/JAM-A) activity by a F11R-derived peptide in breast cancer and its microenvironment

Purpose

To examine the involvement of the F11R/JAM-A protein in breast cancer metastasis, we utilized the F11R/JAM-A antagonistic peptide 4D (P4D) in experiments of transendothelial migration (TEM) of breast cancer cells.

Methods

Experiments were conducted in the mouse 4T1 breast cancer model utilizing the human mammary epithelial cell and endothelial cell lines. The levels of soluble F11R/JAM-A (sJAM-A) in the murine plasmas were measured by ELISA. Levels of F11R/JAM-A mRNA and protein in cell lines were assessed by qRT-PCR and Western blot, respectively. Cell surface expression of F11R/JAM-A was demonstrated by flow cytometry. Functional tests included the TEM of breast cancer cells and adhesion of breast cancer cells to the endothelium. The endothelial permeability was studied by fluorescent tracer assay and by the Real-Time Cell Analysis (RTCA).

Results

The tumor inducers Tβ4 and TGF-β1 reduced the levels of sJAM-A in murine plasma, and reduced the F11R/JAM-A protein levels in the human microvascular endothelial cell line HMEC-1. The adhesion and TEM measured between breast cancer cells and inflamed or Tβ4-treated endothelium were inhibited by P4D. The presence of P4D did not destabilize the pre-existing tight junctions in the endothelial monolayer. The barrier-protecting effect of P4D was stronger than that of forskolin, when a booster dose of P4D was applied to the inflamed endothelium.

Conclusions

F11R/JAM-A protein can be considered as a novel target in the treatment of breast cancer metastasis. In vivo and clinical studies are needed to further investigate the effectiveness of F11R/JAM-A-derived peptide as a possible anti-metastatic drug.

Electronic supplementary material

The online version of this article (10.1007/s10549-019-05471-x) contains supplementary material, which is available to authorized users.

Investigation of JAM-A (rs790056) and LFA-1 (rs8058823) gene variants in Turkish colorectal cancer patients

BACKGROUND/AIMS

Lymphocyte function-associated antigen 1 (LFA-1) is a transmembrane glycoprotein expressed on the surface of leukocytes and containing the binding domain for junctional adhesion molecule-A (JAM-A). The aim of the present study was to evaluate the effects of JAM-A and LFA-1 variants on the formation of colorectal cancer and metastasis.

MATERIALS AND METHODS

A total of 82 subjects with colorectal cancer and 67 healthy subjects were studied. DNA was isolated from blood samples, and variations were determined using the polymerase chain reaction and restriction fragment length polymorphism method.

RESULTS

JAM-A rs790056 CC genotype and C allele were found to be higher in the colorectal cancer group (p<0.05), and approximately 3-fold increased colorectal cancer risk with CC genotype was determined (p=0.029). Haplotype analysis showed that GC haplotype (LFA-1 rs8058823G and JAM-A rs790056C) frequency was significantly higher in the patient group (p=0.041) than in controls.

CONCLUSION

JAM-A rs790056 variation may be effective in the development of colorectal cancer.

Dysregulation of junctional adhesion molecule-A via p63/GATA-3 in head and neck squamous cell carcinoma

Junctional adhesion molecule-A (JAM-A), which belongs to the IgG superfamily, is a tight junction molecule associated with epithelial and endothelial barrier function. Overexpression of JAM-A is also closely associated with invasion and metastasis of cancers such as breast cancer, lung cancer and pancreatic cancer. However, little is known about the mechanism in overexpression of JAM-A in head and neck squamous cell carcinoma (HNSCC). In the present study, we found high expression of JAM-A at the protein and mRNA levels in HNSCC tissues, including those of the oropharynx, larynx, and hypopharynx, together with high protein expression of β-catenin, p63, ΔNp63 and GATA-3. Furthermore, in ELISA, a significant increase of soluble JAM-A in the sera of HNSCC patients was observed compared to healthy subjects. Knockdown of JAM-A by siRNA inhibited cell proliferation, invasion and migration in the HNSCC cell line Detroit562 in vitro. JAM-A expression in Detroit562 was increased via a distinct signal transduction pathway including NF-κB. Expression of JAM-A, β-catenin, p63 and ΔNp63 in Detroit562 was decreased under hypoxia. Knockdown of p63, ΔNp63 or GATA-3 by siRNAs reduced JAM-A expression in Detroit562. In primary cultured HNSCC cells in which CK7, p63, ΔNp63 and GATA-3 were detected, JAM-A expression was decreased by knockdown of p63 or ΔNp63. These results indicate that JAM-A is a biomarker of malignancy in HNSCC and that plasma soluble JAM-A may contribute to serum-based diagnosis of HNSCC. The mechanism of dysregulation of JAM-A via p63/GATA-3 is important in possible molecular targeted therapy for HNSCC.

JAM-A as a prognostic factor and new therapeutic target in multiple myeloma

Cell adhesion in the multiple myeloma (MM) microenvironment has been recognized as a major mechanism of MM cell survival and the development of drug resistance. Here we addressed the hypothesis that the protein junctional adhesion molecule-A (JAM-A) may represent a novel target and a clinical biomarker in MM. We evaluated JAM-A expression in MM cell lines and in 147 MM patient bone marrow aspirates and biopsies at different disease stages. Elevated JAM-A levels in patient-derived plasma cells were correlated with poor prognosis. Moreover, circulating soluble JAM-A (sJAM-A) levels were significantly increased in MM patients as compared with controls. Notably, in vitro JAM-A inhibition impaired MM migration, colony formation, chemotaxis, proliferation and viability. In vivo treatment with an anti-JAM-A monoclonal antibody (αJAM-A moAb) impaired tumor progression in a murine xenograft MM model. These results demonstrate that therapeutic targeting of JAM-A has the potential to prevent MM progression, and lead us to propose JAM-A as a biomarker in MM, and sJAM-A as a serum-based marker for clinical stratification.

Junctional Adhesion Molecules (JAMs): Cell Adhesion Receptors With Pleiotropic Functions in Cell Physiology and Development

Junctional adhesion molecules (JAM)-A, -B and -C are cell-cell adhesion molecules of the immunoglobulin superfamily which are expressed by a variety of tissues, both during development and in the adult organism. Through their extracellular domains, they interact with other adhesion receptors on opposing cells. Through their cytoplasmic domains, they interact with PDZ domain-containing scaffolding and signaling proteins. In combination, these two properties regulate the assembly of signaling complexes at specific sites of cell-cell adhesion. The multitude of molecular interactions has enabled JAMs to adopt distinct cellular functions such as the regulation of cell-cell contact formation, cell migration, or mitotic spindle orientation. Not surprisingly, JAMs regulate diverse processes such as epithelial and endothelial barrier formation, hemostasis, angiogenesis, hematopoiesis, germ cell development, and the development of the central and peripheral nervous system. This review summarizes the recent progress in the understanding of JAMs, including their characteristic structural features, their molecular interactions, their cellular functions, and their contribution to a multitude of processes during vertebrate development and homeostasis.

Endothelial Cell Junctional Adhesion Molecules: Role and Regulation of Expression in Inflammation

Endothelial cells line the lumen of all blood vessels and play a critical role in maintaining the barrier function of the vasculature. Sealing of the vessel wall between adjacent endothelial cells is facilitated by interactions involving junctionally expressed transmembrane proteins, including tight junctional molecules, such as members of the junctional adhesion molecule family, components of adherence junctions, such as VE-Cadherin, and other molecules, such as platelet endothelial cell adhesion molecule. Of importance, a growing body of evidence indicates that the expression of these molecules is regulated in a spatiotemporal manner during inflammation: responses that have significant implications for the barrier function of blood vessels against blood-borne macromolecules and transmigrating leukocytes. This review summarizes key aspects of our current understanding of the dynamics and mechanisms that regulate the expression of endothelial cells junctional molecules during inflammation and discusses the associated functional implications of such events in acute and chronic scenarios.

Developing Potential Candidates of Preclinical Preeclampsia

The potential for developing molecules of interest in preclinical preeclampsia from candidate genes that were discovered on gene expression microarray analysis has been challenged by limited access to additional first trimester trophoblast and decidual tissues. The question of whether these candidates encode secreted proteins that may be detected in maternal circulation early in pregnancy has been investigated using various proteomic methods. Pilot studies utilizing mass spectrometry based proteomic assays, along with enzyme linked immunosorbent assays (ELISAs), and Western immunoblotting in first trimester samples are reported. The novel targeted mass spectrometry methods led to robust multiple reaction monitoring assays. Despite detection of several candidates in early gestation, challenges persist. Future antibody-based studies may lead to a novel multiplex protein panel for screening or detection to prevent or mitigate preeclampsia.

Atherogenic mononuclear cell recruitment is facilitated by oxidized lipoprotein-induced endothelial junctional adhesion molecule-A redistribution

BACKGROUND

Junctional adhesion molecule (JAM-) A is a transmembrane protein expressed in many cell types and maintains junctional integrity in endothelial cells. Upon inflammatory stimulation, JAM-A relocates to the apical surface and might thereby facilitate the recruitment of leukocytes.

OBJECTIVE

Although inflammatory JAM-A redistribution is an established process, further effort is required to understand its exact role in the transmigration of mononuclear cells, particularly under atherogenic conditions.

METHODS

By the use of RNA interference and genetic deletion, the role of JAM-A in the transmigration of T cells and monocytes through aortic endothelial cells was investigated. JAM-A-localization and subsequent mononuclear cell rolling, adhesion and transmigration were explored during endothelial inflammation, induced by oxidized LDL or cytokines.

RESULTS

RNA interference or genetic deletion of JAM-A in aortic endothelial cells resulted in a decreased transmigration of mononuclear cells. Treatment of the endothelial cells with oxLDL resulted in an increase of both permeability and apical JAM-A presentation, as shown by bead adhesion and confocal microscopy experiments. Redistribution of JAM-A resulted in an increased leukocyte adhesion and transmigration, which could be inhibited with antibodies against JAM-A or by lovastatin-treatment, but not with the peroxisome proliferator activated receptor gamma-agonist pioglitazone.

CONCLUSIONS

This study demonstrates that redistribution of JAM-A in endothelial cells after stimulation with pro-atherogenic oxidized lipoproteins results in increased transmigration of mononuclear cells. This inflammatory dispersal of JAM-A could be counteracted with statins, revealing a novel aspect of their mechanism of action.

Differential expression of junctional adhesion molecules in different stages of systemic sclerosis

OBJECTIVE

Systemic sclerosis (SSc) is characterized by early perivascular inflammation, microvascular endothelial cell (MVEC) activation/damage, and defective angiogenesis. Junctional adhesion molecules (JAMs) regulate leukocyte recruitment to sites of inflammation and ischemia-reperfusion injury, vascular permeability, and angiogenesis. This study was undertaken to investigate the possible role of JAMs in SSc pathogenesis.

METHODS

JAM-A and JAM-C expression levels in skin biopsy samples from 25 SSc patients and 15 healthy subjects were investigated by immunohistochemistry and Western blotting. Subcellular localization of JAMs in cultured healthy dermal MVECs and SSc MVECs was assessed by confocal microscopy. Serum levels of soluble JAM-A (sJAM-A) and sJAM-C in 64 SSc patients and 32 healthy subjects were examined by enzyme-linked immunosorbent assay.

RESULTS

In control skin, constitutive JAM-A expression was observed in MVECs and fibroblasts. In early-stage SSc skin, JAM-A expression was strongly increased in MVECs, fibroblasts, and perivascular inflammatory cells. In late-stage SSc, JAM-A expression was decreased compared with controls. JAM-C was weakly expressed in control and late-stage SSc skin, while it was strongly expressed in MVECs, fibroblasts, and inflammatory cells in early-stage SSc. Surface expression of JAM-A was higher in early-stage SSc MVECs and increased in healthy MVECs stimulated with early-stage SSc sera. JAM-C was cytoplasmic in resting healthy MVECs, while it was recruited to the cell surface upon challenge with early-stage SSc sera. Early-stage SSc MVECs exhibited constitutive surface JAM-C expression. In SSc, increased levels of sJAM-A and sJAM-C correlated with early disease and measures of vascular damage.

CONCLUSION

Our findings indicate that JAMs may participate in MVEC activation, inflammatory processes, and impaired angiogenesis in different stages of SSc.

Upregulation of junctional adhesion molecule-A is a putative prognostic marker of hypertension

Aims

Establishing biochemical markers of pre-hypertension and early hypertension could help earlier diagnostics and therapeutic intervention. We assess dynamics of junctional adhesion molecule-A (JAM-A) expression in rat models of hypertension and test whether JAM-A expression could be driven by angiotensin (ANG) II and whether JAM-A contributes to the progression of hypertension. We also compare JAM-A expression in normo- and hypertensive humans.

Methods and results

In pre-hypertensive and spontaneously hypertensive rats (SHRs), JAM-A protein was overexpressed in the brainstem microvasculature, lung, liver, kidney, spleen, and heart. JAM-A upregulation at early and late stages was even greater in the stroke-prone SHR. However, JAM-A was not upregulated in leucocytes and platelets of SHRs. In Goldblatt 2K-1C hypertensive rats, JAM-A expression was augmented before any increase in blood pressure, and similarly JAM-A upregulation preceded hypertension caused by peripheral and central ANG II infusions. In SHRs, ANG II type 1 (AT₁) receptor antagonism reduced JAM-A expression, but the vasodilator hydralazine did not. Body-wide downregulation of JAM-A with Vivo-morpholinos in juvenile SHRs delayed the progression of hypertension. In the human saphenous vein, JAM-A mRNA was elevated in hypertensive patients with untreated hypertension compared with normotensive patients but reduced in patients treated with renin–angiotensin system antagonists.

Conclusion

Body-wide upregulation of JAM-A in genetic and induced models of hypertension in the rat precedes the stable elevation of arterial pressure. JAM-A upregulation may be triggered by AT₁ receptor-mediated signalling. An association of JAM-A with hypertension and sensitivity to blockers of ANG II signalling were also evident in humans. We suggest a prognostic and possibly a pathogenic role of JAM-A in arterial hypertension.

Plasma adrenomedullin level is related to a single nucleotide polymorphism in the adrenomedullin gene

OBJECTIVE

Adrenomedullin (ADM) plays an important role in inflammation and is a marker of future cardiovascular events. We studied common single nucleotide polymorphisms (SNPs) in the gene encoding ADM and their relationship with the plasma levels of ADM and other inflammatory markers.

DESIGN AND METHODS

Plasma ADM, interleukin 6 (IL6), fibrinogen, and C-reactive protein (CRP) were measured in 476 subjects from the population-based Hong Kong Cardiovascular Risk Factor Prevalence Study-2. Four tag SNPs in ADM were genotyped.

RESULTS

Plasma ADM level increased with decreasing plasma IL6 level (β=-0.116, P=0.014). Plasma ADM level was not related to plasma levels of CRP and fibrinogen, and other clinical characteristics, except age (P=0.049). The four SNPs, rs3814700, rs11042725, rs34354539, and rs4910118, had minor allele frequencies of 31.1, 28.7, 33.8, and 23.4% respectively. Carriers of the minor allele of rs4910118 had a mean plasma ADM level that was 10.5% (95% confidential interval: 2.5-17.8%) lower than the non-carriers (β=-0.115, P=0.011). Haplotype analysis revealed a similar significant association with plasma ADM (P=0.040). In multivariate analysis, the presence of the minor allele of rs4910118, but not plasma IL6, was independently associated with plasma ADM (P=0.010).

CONCLUSION

Plasma ADM correlates with plasma IL6 level, consistent with its role in inflammation. It is related to an SNP common in Chinese, independent of other covariates. ADM genotype should be included in future studies of cardiovascular risk prediction.

Transcription and translation of human F11R gene are required for an initial step of atherogenesis induced by inflammatory cytokines

BACKGROUND

The F11 Receptor (F11R; aka JAM-A, JAM-1) is a cell adhesion protein present constitutively on the membrane surface of circulating platelets and within tight junctions of endothelial cells (ECs). Previous reports demonstrated that exposure of ECs to pro-inflammatory cytokines causes insertion of F11R molecules into the luminal surface of ECs, ensuing with homologous interactions between F11R molecules of platelets and ECs, and a resultant adhesion of platelets to the inflamed ECs. The main new finding of the present report is that the first step in this chain of events is the de-novo transcription and translation of F11R molecules, induced in ECs by exposure to inflammatory cytokines.

METHODS

The experimental approach utilized isolated, washed human platelet suspensions and cultured human venous endothelial cells (HUVEC) and human arterial endothelial cells (HAEC) exposed to the proinflammatory cytokines TNF-alpha and/or IFN-gamma, for examination of the ability of human platelets to adhere to the inflamed ECs thru the F11R. Our strategy was based on testing the effects of the following inhibitors on this activity: general mRNA synthesis inhibitors, inhibitors of the NF-kappaB and JAK/STAT pathways, and small interfering F11R-mRNA (siRNAs) to specifically silence the F11R gene.

RESULTS

Treatment of inflamed ECs with the inhibitors actinomycin, parthenolide or with AG-480 resulted in complete blockade of F11R- mRNA expression, indicating the involvement of NF-kappaB and JAK/STAT pathways in this induction. Transfection of ECs with F11R siRNAs caused complete inhibition of the cytokine-induced upregulation of F11R mRNA and inhibition of detection of the newly- translated F11R molecules in cytokine-inflamed ECs. The functional consequence of the inhibition of F11R transcription and translation was the significant blockade of the adhesion of human platelets to inflamed ECs.

CONCLUSION

These results prove that de novo synthesis of F11R in ECs is required for the adhesion of platelets to inflamed ECs. Because platelet adhesion to an inflamed endothelium is crucial for plaque formation in non-denuded blood vessels, we conclude that the de-novo translation of F11R is a crucial early step in the initiation of atherogenesis, leading to atherosclerosis, heart attacks and stroke.

THE AUTODIGESTION HYPOTHESIS AND RECEPTOR CLEAVAGE IN DIABETES AND HYPERTENSION

One of the key features of cardiovascular complications, such as hypertension or diabetes, is that they often appear at the same time in the same individual together with other forms of co-morbidities. While clinically a recognized phenomenon, no molecular mechanism for such co-morbidities has received universal acceptance. We propose a new hypothesis that provides a molecular basis for co-morbidities in hypertension due to unchecked proteolytic activity and receptor destruction. Testing of the hypothesis in the spontaneously hypertensive rat reveals an unchecked matrix metalloproteinase and serine protease activity in plasma and on several cardiovascular and parenchymal cells. The elevated proteolytic activity causes extracellular cleavage of multiple receptor types, such that cleavage of one receptor type leads to loss of the function carried out by this receptor. Proteolytic cleavage of the extracellular domain of the β(2) adrenergic receptor in arteries and arterioles causes vasoconstriction and elevation of the central blood pressure while cleavage of the extracellular domain of the insulin receptor leads to insulin resistance and lack of transmembrane glucose transport. A diverse set of cell dysfunctions in the spontaneously hypertensive rat are accompanied by cleavage of the membrane receptors that are involved in these functions. Chronic inhibition of the unchecked protease activity in the spontaneously hypertensive rat serves to restore the extracellular receptor density and alleviates the corresponding cell dysfunctions. The mild unchecked proteolytic activity in the spontaneously hypertensive rat points towards a chronic autodigestion process as a contributor to the end organ injury encountered in this rat strain. The presence of various soluble receptors, which consist of extracellular fragments of membrane receptors, in the plasma of hypertensive and diabetic patients suggest that the autodigestion process may also be present in man.

Evaluation of soluble junctional adhesion molecule-A as a biomarker of human brain endothelial barrier breakdown

BACKGROUND

An inducible release of soluble junctional adhesion molecule-A (sJAM-A) under pro-inflammatory conditions was described in cultured non-CNS endothelial cells (EC) and increased sJAM-A serum levels were found to indicate inflammation in non-CNS vascular beds. Here we studied the regulation of JAM-A expression in cultured brain EC and evaluated sJAM-A as a serum biomarker of blood-brain barrier (BBB) function.

METHODOLOGY/PRINCIPAL FINDINGS

As previously reported in non-CNS EC types, pro-inflammatory stimulation of primary or immortalized (hCMEC/D3) human brain microvascular EC (HBMEC) induced a redistribution of cell-bound JAM-A on the cell surface away from tight junctions, along with a dissociation from the cytoskeleton. This was paralleled by reduced immunocytochemical staining of occludin and zonula occludens-1 as well as by increased paracellular permeability for dextran 3000. Both a self-developed ELISA test and Western blot analysis detected a constitutive sJAM-A release by HBMEC into culture supernatants, which importantly was unaffected by pro-inflammatory or hypoxia/reoxygenation challenge. Accordingly, serum levels of sJAM-A were unaltered in 14 patients with clinically active multiple sclerosis compared to 45 stable patients and remained unchanged in 13 patients with acute ischemic non-small vessel stroke over time.

CONCLUSION

Soluble JAM-A was not suited as a biomarker of BBB breakdown in our hands. The unexpected non-inducibility of sJAM-A release at the human BBB might contribute to a particular resistance of brain EC to inflammatory stimuli, protecting the CNS compartment.

Poly(I:C) reduces expression of JAM-A and induces secretion of IL-8 and TNF-α via distinct NF-κB pathways in human nasal epithelial cells

Human nasal epithelium is an important physical barrier and innate immune defense protecting against inhaled substances and pathogens. Toll-like receptor (TLR) signaling, which plays a key role in the innate immune response, has not been well characterized in human nasal epithelial cells (HNECs), including the epithelial tight junctional barrier. In the present study, mRNAs of TLR1-10 were detected in hTERT-transfected HNECs, which can be used as an indispensable and stable model of normal HNECs, similar to primary cultured HNECs. To investigate the changes of tight junction proteins and the signal transduction pathways via TLRs in HNECs in vitro, hTERT-transfected HNECs were treated with TLR2 ligand P(3)CSK(4), TLR3 ligand poly(I:C), TLR4 ligand LPS, TLR7/8 ligand CL097, TLR8 ligand ssRNA40/LyoVec, and TLR9 ligand ODN2006. In hTERT-transfected HNECs, treatment with poly(I:C) significantly reduced expression of the tight junction protein JAM-A and induced secretion of proinflammatory cytokines IL-8 and TNF-α. Both the reduction of JAM-A expression and the induction of secretion of IL-8 and TNF-α after treatment with poly(I:C) were modulated by distinct signal transduction pathways via EGFR, PI3K, and p38 MAPK and finally regulated by a TLR3-mediated NF-κB pathway. The control of TLR3-mediated signaling pathways in HNECs may be important not only in infection by viral dsRNA but also in autoimmune diseases caused by endogenous dsRNA released from necrotic cells.

Silencing of the F11R gene reveals a role for F11R/JAM-A in the migration of inflamed vascular smooth muscle cells and in atherosclerosis

RATIONALE AND OBJECTIVE

Our previous studies have determined that the F11 receptor (F11R; aka JAM-A) exerts a critical force in the adhesion of human platelets to inflamed endothelial cells (ECs), and thus can play a significant role in the initiation of atherosclerotic plaque formation. In the present study, we focus on a subsequent event in plaque development--the migration of smooth muscle cells (SMCs) from the media to the intima of inflamed vessels. Here we report our investigation of the expression of F11R in atherosclerotic arteries of coronary artery disease (CAD) patients, and of the role of F11R in the migration of SMCs involved in atherogenesis.

METHODS AND RESULTS

Histological staining and specific-antibody immunofluorescence of excised, human atherosclerotic coronary arteries revealed the expression of F11R in the SMCs of the intima. RT-PCR and SDS-PAGE followed by immunoblotting procedures demonstrated that F11R mRNA and the F11R protein levels were enhanced by the stimulation of cultured human aortic SMCs with a combined treatment of proinflammatory cytokines (TNFalpha+INFgamma+IL-beta1). Neither the F11R message nor protein was expressed in non-stimulated SMCs. The functional role of F11R in SMCs' migration was studied in cytokine-stimulated SMCs by interference of F11R expression with siRNA. Silencing of the F11R gene of cytokines-treated SMCs inhibited the expression of both F11R mRNA and F11R protein. Functionally, silencing of the F11R gene blocked the proliferation and migration of these inflamed SMCs, both critical events in atherogenesis.

CONCLUSIONS

The new findings of this study are that F11R mRNA and F11R protein are expressed in SMCs of the intima (but not in the media) of atherosclerotic arteries of CAD patients, and that F11R is required for the proliferation and migration of inflamed SMCs. Based on these findings, we conclude that in addition to the previously reported role of F11R in the initiation of plaque formation, F11R plays also an important role in the subsequent growth of atherosclerotic plaques. Identification of drugs that interfere with these pathophysiologic actions of F11R thus represents an effective new approach for the prevention and treatment of atherosclerosis, heart attacks and stroke.