Platelet Endothelial Adhesion Molecule-1 Research Articles

Human and porcine aortic valve endothelial and interstitial cell isolation and characterization.

Calcific aortic valve stenosis (AVS) is defined by pathological changes in the aortic valve (AV) and their predominant cell types: valvular interstitial (VICs) and endothelial cells (VECs). Understanding the cellular and molecular mechanisms of this disease is a prerequisite to identify potential pharmacological treatment strategies. In this study, we present a unique aortic valve cell isolation technique to acquire specific human and porcine cell populations and compared VICs and VECs of these species with each other for the first time. AV cells were isolated from tissue obtained from human patients undergoing surgical aortic valve replacement (SAVR) or from porcine hearts. Functional analysis and in vitro experiments revealed that endothelial-to-mesenchymal transition (EndMT) can be induced in hVECs, leading to a significant increase in mesenchymal markers. In vitro calcification experiments of VICs demonstrated pronounced expression of calcification markers and visible calcific deposits in Alizarin Red staining in both species after incubation with pro-calcific media. Cells isolated from patient-derived AVs showed mesenchymal and endothelial-specific gene signatures (VIC and VEC, respectively). For instance, von Willebrand factor (vWF) and platelet endothelial adhesion molecule-1 (PECAM1) were upregulated in VECs, while the myofibroblastic markers alpha-smooth muscle actin (α-SMA) and vimentin (VIM) were downregulated in VECs compared to VICs. Analysis of cell function by migration revealed that VECs are more migratory than VICs. Induction of EndMT in vitro in VECs displayed increased expression of EndMT markers and decreased expression of endothelial markers, confirming their mesenchymal transdifferentiation ability. In vitro calcification of VICs revealed upregulation of alkaline phosphatase (ALPL), a hallmark of calcification. In addition, other calcification-related genes such as osteocalcin (BGLAP) and runt-related factor 2 (RUNX2) were upregulated. Alizarin red staining of calcified cells provided a further layer of confirmation that the isolated cells were VICs with osteoblastic differentiation capacity. This study aims to take a first step towards standardizing a reproducible isolation technique for specific human and porcine VEC and VIC populations. A comparison of human and porcine aortic valve cells demonstrated that porcine cells may serve as an alternative cellular model system in settings where human tissue is difficult to obtain.

Differential procoagulatory response of microvascular, arterial and venous endothelial cells upon inflammation in vitro

IntroductionInflammation induces a procoagulant phenotype of endothelial cells (EC) with the exposure of tissue factor (TF), a potent initiator of the extrinsic coagulation cascade. Although systemic inflammation affects the whole vascular system, thrombotic lesions occur particularly in microcirculation. This raises the question of whether TF-procoagulant activity (TF-PCA) differs between EC from arterial, venous, and microvascular beds. Materials and methodsFunctional coagulation tests, including TF-PCA, and inflammatory responses were investigated on arterial, venous and microvascular endothelial cells. Interleukin-6 (IL-6) and TF-levels were determined in cohort of 59 septic patients. ResultsWe found that tumor necrosis factor alpha (TNFα), lipopolysaccharide, and interleukin-1β induce a solid, dose-dependent increase in TF-PCA, which is highest in microvascular EC. A positive correlation of interleukin-6 (IL-6) with TF levels was observed in a cohort of 59 septic patients. In contrast, TF-PCA was independent of IL-6 concentrations in vitro. Re-analysis of publicly available gene expression data revealed that among the top 50 genes annotated to coagulation, TF is one of three regulated genes common to the three investigated EC subtypes. The response to inflammatory stimuli in terms of exposure of leukocyte-endothelial- and platelet-endothelial adhesion molecules (E-selectin and PECAM-1), remodeling of adherens junctions, co-exposure of negatively charged surfaces nor breakdown of the glycocalyx was comparable between the EC subtypes and did not explain the higher TF-PCA on microvascular cells. We found that the ratio of TF and TFPI exposure on the endothelial membrane significantly differs between the EC subtypes. ConclusionsThese findings indicate that the ratio of TF to its inhibitor TFPI is a determinant of endothelial TF-PCA, which is most pronounced on microvascular endothelial cells and might explain why the microvascular system is particularly susceptible to inflammation-induced thrombosis.

Association between serum SCUBE1 levels and thrombus burden in patients with ST-segment elevation myocardial infarction

Introduction The signal peptide-CUB-EGF domain-containing protein-1 (SCUBE1) is a recently available biomarker which is expressed by activated and adhered platelets. In present study, we aimed to investigate the association between SCUBE1 levels and thrombus burden in patients with ST elevation myocardial infarction (STEMI) who underwent primary percutaneous coronary intervention (PPCI). Methods A total of 88 patients who were diagnosed with STEMI and underwent PPCI were prospectively included between July 2019 and August 2019. Blood samples were collected for routine biochemistry and serum SCUBE1 levels before PPCI and antiplatelet therapy. Angiographic coronary thrombus burden was classified based on thrombolysis in myocardial infarction (TIMI) thrombus grades. We formed two groups based on the thrombus grade: 37 (42%) patients had high thrombus burden whereas 51 (58%) patients had low thrombus burden. Results The mean age of study population was 58.2 ± 11.8 years (34% female). The mean peak troponin I level, SCUBE1 level, SYNTAX score, and pain-to-balloon time were significantly higher in the high thrombus burden group compared to the low thrombus burden group (p < .05, for all). In ROC analysis, SCUBE1 level >65.63 ng/dL had a sensitivity of 91.9% and a specificity of 76.6% to predict high thrombus burden (AUC: 0.9256; p < .001). In multivariate analysis, SCUBE1 level (HR: 1.133, p = .004) and troponin (HR: 1.002; 95% CI 1.001–1.004, p = .003) were independent predictors of high thrombus burden. Conclusion In the present study, we showed that SCUBE1, a novel platelet-endothelial adhesion molecule and a marker of platelet activation, is an independent predictor of high thrombus burden in patients with STEMI.

CD31 acts as a checkpoint molecule and is modulated by FcγR-mediated signaling in monocytes

Abstract Monocytes and macrophages express Fc-gamma Receptors (FcγR) that engage IgG immune complexes such as antibody-opsonized pathogens or cancer cells to destroy them by various mechanisms including phagocytosis. FcγR-mediated phagocytosis is regulated by the concerted actions of activating FcγR and inhibitory receptors such as FcγRIIb and SIRPα. Here, we report that another ITIM-containing receptor, Platelet Endothelial Adhesion Molecule-1 (PECAM1/CD31), regulates FcγR function, and is itself regulated by FcγR activation. First, qRT-PCR and flow cytometry analyses revealed that monocyte FcγR activation leads to significant downregulation of CD31 expression, both at the message level and at surface expression. Interestingly, the kinetics of downregulation between the two varied, with surface expression reducing earlier than the message. Experiments to analyze the mechanism behind this discrepancy revealed that loss of surface expression was due to internalization, which depended predominantly on the PI3 Kinase pathway. Finally, functional analyses showed that downregulation of CD31 expression in monocytes by siRNA enhanced FcγR-mediated phagocytic ability. Together, these results suggest that CD31 functions as a checkpoint receptor that could be targeted to enhance FcγR functions in antibody-mediated therapies.

Localization, Occurrence, and CSF Changes of SP-G, a New Surface Active Protein with Assumable Immunoregulatory Functions in the CNS.

Conventional surfactant proteins (A, B, C, and D) are important players of the innate immunity in the central nervous system and serve as effective regulators of cerebrospinal fluid rheology, probably being involved in clearance of detrimental metabolites like beta-amyloid and phospho-tau. Recently, a novel surfactant protein, SP-G, was described in kidneys and peripheral endocrine and exocrine glands. So far, its presence and possible functions in the central nervous system are unknown. Therefore, our study aimed to elucidate the presence of SP-G in the brain and its concentration in normal and pathologic samples of cerebrospinal fluid in order to gain first insight into its regulation and possible functions. A total of 121 samples of human cerebrospinal fluid (30 controls, 60 hydrocephalus patients, 7 central nervous system infections, and 24 brain hemorrhage patients) and 21 rat brains were included in our study. CSF samples were quantified using a commercially available ELISA system. Results were analyzed statistically using SPSS 22, performing Spearman Rho correlation and ANOVA with Dunnett's post hoc analysis. Rat brains were investigated via immunofluorescence to determine SP-G presence and colocalization with common markers like aquaporin-4, glial fibrillary acidic protein, platelet endothelial adhesion molecule 1, and neuronal nuclear antigen. SP-G occurs associated with brain vessels, comparable to other conventional SPs, and is present in a set of cortical neurons. SP-G is furthermore actively produced by ependymal and choroid plexus epithelium and secreted into the cerebrospinal fluid. Its concentrations are low in control subjects and patients suffering from aqueductal stenosis, higher in normal pressure hydrocephalus (p < 0.01), and highest in infections of the central nervous system and brain hemorrhage (p < 0.001). Interestingly, SP-G did correlate with total CSF protein in patients with CNS infections and hemorrhage, but not with cell count. Based on the changes in CSF levels of SP-G in hydrocephalus, brain hemorrhage, and CNS infections as well as its abundance at CSF flow-related anatomical structures closely associated with immunological barrier systems, importance for CSF rheology, brain waste clearance, and host defense is assumable. Thus, SP-G is a potential new CSF biomarker, possibly not only reflecting aspects of CNS innate immune responses, but also rheo-dynamically relevant changes of CSF composition, associated with CSF malabsorbtion. However, further studies are warranted to validate our findings and increase insight into the physiological importance of SP-G in the CNS.

The role of SCUBE1 in the development of late stent thrombosis presenting with ST-elevation myocardial infarction

Introduction and AimThere is an important link between platelets and inflammation, thrombosis, and vascular and tissue repair mechanisms. SCUBE1 (signal peptide-CUB-EGF domain-containing protein 1) may function as a novel platelet-endothelial adhesion molecule and play pathological roles in cardiovascular biology. Stent thrombosis (ST) following percutaneous coronary intervention is an uncommon and potentially catastrophic event that can manifest as myocardial infarction and sudden death. High platelet reactivity is a risk factor for thrombotic events, including late ST. For this reason, in the current study, we researched the role of SCUBE1 in the development of late coronary ST. MethodsWe included 40 patients admitted to our hospital with a diagnosis of ST-elevation myocardial infarction (STEMI) and signs of late ST on a coronary angiogram. For the control group, we recruited 50 healthy gender- and age-matched individuals who were seen for health check-ups. We also randomly included 100 patients with a diagnosis of STEMI without ST. ResultsThere were no significant differences between the groups in terms of baseline and demographic characteristics. The mean SCUBE1 level in patients with STEMI with late ST at admission and the STEMI without ST group was significantly higher than in the control group (p<0.01). The mean SCUBE1 level in the STEMI with late ST group was significantly higher than in the STEMI without ST group (p=0.03). In multivariate regression analysis, serum SCUBE1 (odds ratio [OR]: 1.022; 95% confidence interval [CI]: 1.011-1.033, p<0.001) remained an independent predictor for the presence of late ST. In addition, receiver operating characteristic curve analysis was used to determine the optimal SCUBE1 cut-off value for predicting late ST. The area under the curve was 0.972 (95% CI 0.95-0.98). The SCUBE1 cut-off value was 59.2 ng/ml, with a sensitivity of 95.4% and specificity of 82.9%. ConclusionThe present work is the first clinical study to demonstrate that serum SCUBE1 levels are significantly higher in patients with late ST and serum SCUBE1 was an independent predictor for the presence of late ST in our study population.

Topical delivery of l-theanine ameliorates TPA-induced acute skin inflammation via downregulating endothelial PECAM-1 and neutrophil infiltration and activation

l-theanine, the most abundant free amino acid in tea, has been documented to possess many different bioactive properties through oral or intragastrical delivery. However, little is known about the effect of topical delivery of l-theanine on acute inflammation. In the present study, by using 12-O-tetradecanoylphorbol-13-acetate (TPA, 2.5 μg/ear)-induced ear edema model in mice, we first found that single-dose local pretreatment of l-theanine 30 min before TPA time- and dose-dependently suppressed the increases in both skin thickness and weight. Subsequently l-theanine ameliorated TPA-induced erythema, vascular permeability increase, epidermal and dermal hyperplasia, neutrophil infiltration and activation via downregulating the expression of PECAM-1 (a platelet endothelial adhesion molecule-1) in blood vessels and the production of pro-inflammatory cytokines IL-1β, TNF-α, and mediator cyclooxygenase-2 (COX-2), which is mainly expressed in neutrophils. It highlighted the potential of l-theanine as a locally administrable therapeutic agent for acute cutaneous inflammation.

Vitamin E isoforms (d α-tocopherol and δ-tocotrienol) promote healing of secondary skin wounds in diabetic rats

l-theanine, the most abundant free amino acid in tea, has been documented to possess many different bioactive properties through oral or intragastrical delivery. However, little is known about the effect of topical delivery of l-theanine on acute inflammation. In the present study, by using 12-O-tetradecanoylphorbol-13-acetate (TPA, 2.5 μg/ear)-induced ear edema model in mice, we first found that single-dose local pretreatment of l-theanine 30 min before TPA time- and dose-dependently suppressed the increases in both skin thickness and weight. Subsequently l-theanine ameliorated TPA-induced erythema, vascular permeability increase, epidermal and dermal hyperplasia, neutrophil infiltration and activation via downregulating the expression of PECAM-1 (a platelet endothelial adhesion molecule-1) in blood vessels and the production of pro-inflammatory cytokines IL-1β, TNF-α, and mediator cyclooxygenase-2 (COX-2), which is mainly expressed in neutrophils. It highlighted the potential of l-theanine as a locally administrable therapeutic agent for acute cutaneous inflammation.

Expression of blood vessel growth inhibitory factor and platelet endothelial adhesion molecules 34 in hepatocellular carcinoma tissue and its clinical significance

Objective To investigate the effect and mechanism of advanced oxidation protein products (AOPP) on the proliferation of CD4+ CD25+ regulatery T cells (Tregs). Methods Tregs and CD4+ CD25- T cells (worked as effective T cells, Teff) were isolated, and dendrtic cells (DCs) were induced from the human peripheral blood mononuclear cells. Tregs (5×104/well) were co-cultured with Mitomycin-inactivated DCs loaded with allogeneic antigen and IL-2 (100 U/ml), and according to the presence of AOPP into 3 different groups: Control group (200 μg/ml serum albumin), AOPP group (200 μg/ml AOPP), Antioxidant group [pretreated with 100 μmol/L diphenyleneiodonium (DPI) 1 h before AOPP was added]. The incorporation of [3H]thymidine was used to evaluate the proliferation of Tregs and the suppressive function of Tregs on the Teff. Western blotting was used to observe the expression of phosphorylated extracellular signal-regulated kinase 1/2 (p-ERK1/2), phosphorylated protein kinase B (p-Akt), phosphorylated signal transducer and activators of transcription 5 (p-STAT5) and p27kip1. Results In AOPP group, the incorporation of [3H]thymidine was (36213.3±3 385.9) cpm, which was significantly lower than that [(65 557.0±3 981.6) cpm] of Control group (P=0.001). In Antioxidant group, the value was (44 827.0±3 694.6) cpm, which was significantly higher than that of AOPP group (P=0.041), but lower than that of Control group (P=0.003). When Tregs and Teff were incubated at the ratio of 1∶1 and 1/2∶1, the suppressive ratios of Tregs on the Teff in AOPP group were (27.3±4.0)% and (23.9±3.7)%, which were significantly lower than those [(68.5±7.9)% and (62.9±5.0)%] of Control group (P=0.001, 0.001). Compared with Control group, addition of AOPP significantly downregulated the expression of p-ERK, p-Akt, p-STAT5 and upregulated the expression of p27kip1 in Tregs (P=0.009, 0.021, 0.036, 0.036). After antioxidants was added, the expression of p-ERK, p-Akt, p-STAT5 was significantly upregulated compared with AOPP group (P=0.034, 0.030, 0.042) and lower than that of Control group (P=0.043, 0.039, 0.007); the expression of p27kip1 was significantly doenregulated compared with AOPP group (P=0.048) and higher than that of Control group (P=0.047). Conclusion AOPP significantly inhibits the proliferation of Tregs through downregulating p-ERK, p-Akt and p-STAT5, and upregulating p27kip1 via oxidative stress in vitro. Key words: Advanced oxidation protein products; Regulatory T cells; Proliferation

Elevated levels of tissue plasminogen activator and E-selectin in male children with autism spectrum disorder.

Although the etiopathology of autism spectrum disorder (ASD) is not clear, immune dysfunction has been proposed as a mechanism for the pathophysiology of ASD. The purpose of this study is to examine serum levels of tissue plasminogen activator (t-PA) and some adhesion molecules in children with ASD that have not been investigated previously in detail. The study group included 35 male children aged from 2 to 9 diagnosed with ASD according to DSM-V criteria. Soluble platelet endothelial adhesion molecule-1 (sPECAM-1), P-selectin, E-selectin, and t-PA in the serum were determined with enzyme-linked immunosorbent assay. Autism behavior check list (ABC) is used for the assessment of ASD severity. The levels of t-PA (P = 0.025) and E-selectin (P = 0.007) was detected significantly higher in children with ASD than control group. Serum levels of sPECAM-1 showed statistically significant negative correlation with sensory, body and object-use, language, social, and self-help and total scores in the patient group (r = -0.349, P = 0.04; r = -0.411, P = 0.01; r = -0.412, P = 0.01; r = -0.417, P = 0.01, and r = -0.531, P < 0.01, respectively). Serum levels of P-selectin levels showed statistically significant negative correlation with ABC total score in the patient group (r = -0.378, P = 0.03). It may be suggested that t-PA, E-selectin, P-selectin, and sPECAM-1 a crucial role in inflammatory conditions in children with ASD. Autism Res 2016, 9: 1241-1247. © 2016 International Society for Autism Research, Wiley Periodicals, Inc.

PROGNOSTIC NEUROBIOCHEMICAL MARKERS OF MULTIPLE SCLEROSIS COURSE

The association of pathobiochemical liquor markers with relapses and progression of multiple sclerosis in 60 patients with remitting-relapsing multiple sclerosis (RRMS) were studied. It is found that risk of MS relapse in the nearest three years is increased when the level of tumor necrosis factor alpha and matrix metalloproteinase 2 in cerebrospinal fluid is higher than median level. The risk of rapid progression of neurological deficit increases when the liquor level of soluble plateletendothelial adhesion molecule 1 (sPECAM-1), soluble adhesion molecules vascular endothelium type 1 (sVCAM-1) and matrix metalloproteinase 2 (MMP-2) exceeds the median level.

Kinin B1 receptor regulates interactions between neutrophils and endothelial cells by modulating the levels of Mac-1, LFA-1 and intercellular adhesion molecule-1.

Kinins are pro-inflammatory peptides that mimic the cardinal features of inflammation. We examined the concept that expression levels of endothelial intercellular adhesion molecule-1 (ICAM-1) and neutrophil integrins Mac-1 and LFA-1 are modulated by the kinin B1 receptor (B1R) agonist, Lys-des[Arg(9)]bradykinin (LDBK). Stimulation of endothelial cells with LDBK increased the levels of ICAM-1 mRNA transcripts/protein, and also of E-selectin and platelet endothelial adhesion molecule-1. ICAM-1 levels increased in a magnitude comparable with that produced by TNF-α. This stimulatory effect was reduced when endothelial cells, which had been previously transfected with a B1R small interfering RNA, were stimulated with LDBK, under comparable conditions. Similarly, LDBK produced a significant increase in protein levels of LFA-1 and Mac-1 integrins in human neutrophils, an effect that was reversed by pretreatment of cells with 10 µg/ml cycloheximide or a B1R antagonist. Functional experiments performed with post-confluent monolayers of endothelial cells stimulated with LDBK and neutrophils primed with TNF-α, and vice versa, resulted in enhanced adhesiveness between both cells. Neutralizing Abs to ICAM-1 and Mac-1 reduced the adhesion between them. Our results indicate that kinin B1R is a novel modulator that promotes adhesion of leukocytes to endothelial cells, critically enhancing the movement of neutrophils from the circulation to sites of inflammation.

Acute effects of ionizing radiation on human endothelial barrier function

The human vasculature is critical to healthy functioning of the tissues of the body and a major factor in maintaining homeostasis is the endothelial barrier. In the brain, the blood–brain barrier (BBB) is highly specialized in order to sustain the neural tissue.Here, we have examined the effects of radiation on BBB models using a unique variety of endpoints to assess barrier function. These include trans-endothelial electrical resistance (TEER), morphological effects, localization of adhesion and cell junction proteins (in two-dimensional monolayers and in three-dimensional tissue models) and permeability of molecules through the endothelial barrier. Two culture conditions were used to represent conditions on the inside or the lumen of vessels and conditions on the outside or ablumenal side of vessels. For the lumen, cells were cultured in serum and growth factor containing media, and for the ablumenal side of vessels, cells were cultured in serum-free defined media.Initial experiments with gamma rays in serum-free conditions revealed a previously unknown acute effect involving cell detachment and the loss of the clinically relevant cell adhesion molecule—cell platelet endothelial adhesion molecule (PECAM)-1 [ 1]. Gamma radiation (5 Gy) induced a rapid and transient decrease in TEER at 3 h, with effects also seen at the lower radiotherapy dose of 2 Gy. This dip in resistance correlated with the transient loss PECAM-1 in discrete areas where cells often detached from the monolayer leaving gaps. Loss in PECAM-1 occurred at least in part as detached microparticles. Redistribution of PECAM-1 microparticles was also seen in three-dimensional human tissue models. By 6 h, the remaining cells had migrated to reseal the barrier, coincident with TEER returning to control levels. Resealed monolayers contained fewer cells per unit area and their barrier function was weakened as corroborated by an increased permeability over 24 h. Because PECAM-1 is involved in barrier function and platelet aggregation, this effect is likely highly relevant to cancer radiotherapy using gamma rays.These studies were extended to include low linear energy transfer (LET) photons of X-rays and ion particles present in the space environment—low LET ion particles including high energy (1 GeV) protons and helium ions. X-rays under serum-free conditions also showed an acute response involving a dip in TEER at 3 h and the loss of PECAM-1 between cells as microparticles. Ion particles, however, did not show these effects of photons under serum-free conditions. Both protons and helium ions at doses up to 5 Gy did not produce this transient change in TEER or PECAM-1, although some longer term effects in TEER were noted.In the presence of serum and growth factors, however, all radiations tested showed short-term effects in TEER, that of a series of symmetrical peaks which diminished in size over several hours. For 1 GeV protons and helium ions, this effect could be fitted to an equation for under-damped oscillation, a pattern typical of a mechanism for timing of events in periodic processes. For gamma and X-rays, the underdamped oscillation was present but superimposed on a drop in resistance at 3 h similar to that seen in serum-free conditions.In conclusion, we have shown two acute effects of low LET radiation on the human endothelial barrier. First, a short-term effect of photons but not ion particles involving a single dip in TEER and the loss of PECAM-1 at 3 h after irradiation, and second an underdamped oscillation of TEER induced by both photons and ion particles that to date does not appear to be associated with the loss of PECAM-1 or any other junction molecules.

Serum levels of soluble platelet endothelial cell adhesion molecule-1 and vascular cell adhesion molecule-1 are decreased in subjects with autism spectrum disorder

BackgroundAdhesion molecules, such as platelet-endothelial adhesion molecule-1 (PECAM-1), platelet selectin (P-selectin), endothelial selectin (E-selectin), intracellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1), are localized on the membranes of activated platelets and leukocytes and on the vascular endothelium. Recently, we measured serum levels of soluble (s) forms of adhesion molecules in adults,18 to 26 years old, with autism spectrum disorder (ASD) and observed low levels of sPECAM-1 and sP-selectin. A subsequent study showed a similar result in children two to four years old with ASD. However, information about school age (five to seventeen years old) ASD subjects is required to determine whether adhesion molecules are also reduced in individuals with ASD in this age range.FindingsTwenty-two subjects with high-functioning ASD and 29 healthy age-matched controls were recruited. ELISA was used for sPECAM-1, and a suspension array system was used for sP-selectin, sE-selectin, sICAM-1 and sVCAM-1 measurements. We found that serum levels of sPECAM-1 (U = 91.0, P<0.0001 by Mann–Whitney U test) and sVCAM-1 (U = 168.0, P = 0.0042) were significantly lower in ASD subjects than in controls. Subsequently, we examined the correlations between serum levels of either sPECAM-1 or sVCAM-1 and clinical variables including Autism Diagnostic Interview - Revised subscores and our previous cytokine profile data from the same ASD subjects. However, we did not find any significant correlations between them.ConclusionsThe present results, taken together with previous results, suggest that sPECAM-1 may play a role in the generation and development of ASD, beginning in childhood and lasting until adulthood.

Levels of Soluble Platelet Endothelial Cell Adhesion Molecule-1 and P-Selectin Are Decreased in Children with Autism Spectrum Disorder

Although the etiopathology of autism spectrum disorder (ASD) is not clear, there is increasing evidence that dysfunction in the immune system affects many children with ASD. Findings of immune dysfunction in ASD include increases in inflammatory cytokines, chemokines, and microglial activity in brain tissue and cerebrospinal fluid, as well as abnormal peripheral immune cell function. Adhesion molecules, such as platelet endothelial adhesion molecule-1 (PECAM-1), intercellular adhesion molecule-1 (ICAM-1), vascular adhesion molecule-1 (VCAM-1), P-selectin, and L-selectin, function to facilitate leukocyte transendothelial migration. We assessed concentrations of soluble adhesion molecules, sPECAM-1, sICAM-1, sVCAM-1, sP-selectin, and sL-selectin in the plasma of 49 participants with ASD and 31 typically developing controls of the same age, all of whom were enrolled as part of the Autism Phenome Project. Behavioral assessment, the levels of soluble adhesion molecules, and head circumference were compared in the same subjects. Levels of sPECAM-1 and sP-selectin were significantly reduced in the ASD group compared to typically developing controls (p < .02). Soluble PECAM-1 levels were negatively associated with repetitive behavior and abnormal brain growth in children with ASD (p = .03). Because adhesion molecules modulate the permeability and signaling at the blood-brain barrier as well as leukocyte infiltration into the central nervous system, the current data suggest a role for these molecules in the complex pathophysiology of ASD.

6-Mercaptopurine Inhibits Atherosclerosis in Apolipoprotein E*3-Leiden Transgenic Mice Through Atheroprotective Actions on Monocytes and Macrophages

6-Mercaptopurine (6-MP), the active metabolite of the immunosuppressive prodrug azathioprine, is commonly used in autoimmune diseases and transplant recipients, who are at high risk for cardiovascular disease. Here, we aimed to gain knowledge on the action of 6-MP in atherosclerosis, with a focus on monocytes and macrophages. We demonstrate that 6-MP induces apoptosis of THP-1 monocytes, involving decreased expression of the intrinsic antiapoptotic factors B-cell CLL/Lymphoma-2 (Bcl-2) and Bcl2-like 1 (Bcl-x(L)). In addition, we show that 6-MP decreases expression of the monocyte adhesion molecules platelet endothelial adhesion molecule-1 (PECAM-1) and very late antigen-4 (VLA-4) and inhibits monocyte adhesion. Screening of a panel of cytokines relevant to atherosclerosis revealed that 6-MP robustly inhibits monocyte chemoattractant chemokine-1 (MCP-1) expression in macrophages stimulated with lipopolysaccharide (LPS). Finally, local delivery of 6-MP to the vessel wall, using a drug-eluting cuff, attenuates atherosclerosis in hypercholesterolemic apolipoprotein E*3-Leiden transgenic mice (P<0.05). In line with our in vitro data, this inhibition of atherosclerosis by 6-MP was accompanied with decreased lesion monocyte chemoattractant chemokine-1 levels, enhanced vascular apoptosis, and reduced macrophage content. We report novel, previously unrecognized atheroprotective actions of 6-MP in cultured monocytes/macrophages and in a mouse model of atherosclerosis, providing further insight into the effect of the immunosuppressive drug azathioprine in atherosclerosis.

Polymorphisms in CD31/PECAM-1 and CD38 Genes Are Associated with Susceptibility to Multiple Myeloma

Interactions with bone marrow microenvironment play a major role in the control of multiple myeloma (MM) growth and survival. MM clonal plasma cells co-express high levels of a signaling receptor CD38 and its ligand, the platelet endothelial adhesion molecule-1, CD31//PECAM-1. Homotypic and heterotypic interactions through these adhesion molecules (CD31/CD31, CD38/CD31 and CD38/hyaluronate interactions) may be involved in the pathogenesis of MM. The objective of this study was to investigate whether inherited variants in CD31/PECAM-1 and CD38 genes influence on susceptibility to MM. A total of 189 Caucasian patients with MM and 209 healthy controls were genotyped with the use of PCR-based methods. Genotyping was performed to assess allelic frequencies of three non-synonymous single nucleotide polymorphisms (SNPs) in CD31/PECAM1 gene including 373C>G (Leu 125Val), 1688G>A (Ser563Asn) and 2008A>G (Arg670Gly) as well as two SNPs in CD38 gene including 184C>G in intron 1 and non-synonymous 418C>T (Arg140Trp) in exon 3. Analyzing the prevalence of investigated genetic variants, we found that allelic frequencies of two SNPs in CD31/PECAM-1 gene and intron 1 184C>G SNP in CD38 gene differed significantly between MM patients and controls. Concerning CD31/PECAM-1 SNPs, the carriership of 373G allele was associated with the relative risk of MM of 4.5 (p=8×10−10), while in carriers of 1688A allele the relative risk of MM reached 3.0 (p=2×10−6). Regarding CD38 gene, compared to wild-type 184C-allele carriers, the carriers of variant 184G-allele had 3.4-fold increased risk of MM (p=1×1−9). In conclusion, the results of this study suggest that inherited variants in ligand-receptor CD31/PECAM1 - CD38 system contribute to the genetic susceptibility to MM in Caucasians.

Decreased Serum Levels of Platelet-Endothelial Adhesion Molecule (PECAM-1) in Subjects with High-Functioning Autism: A Negative Correlation with Head Circumference at Birth

Accumulating evidence suggests that the immune system plays a role in the pathophysiology of autism, and that the adhesion molecules play an important role in the process of inflammation. This study was undertaken to determine whether serum levels of the adhesion molecules in subjects with high-functioning autism are altered as compared with those of normal controls. Seventeen male subjects with high-functioning autism and 22 male age-matched unrelated healthy control subjects were enrolled. Serum levels of the soluble forms of platelet-endothelial adhesion molecule (PECAM-1), intracellular adhesion molecule (ICAM-1), and vascular cell adhesion molecule (VCAM-1) were measured. Levels of PECAM-1, but not ICAM-1, in the subjects with autism were significantly lower than those of control subjects. VCAM-1 showed a weak trend for a lowered level. There was a negative correlation between serum levels of PECAM-1 and head circumference at birth in the autistic subjects. These results suggest that PECAM-1 plays a role in the pathophysiology of high-functioning autism.

Dengue‐virus‐infected dendritic cells trigger vascular leakage through metalloproteinase overproduction

Dengue virus (DV) is an important re-emerging arthropod-borne virus of global significance. The defining characteristic of DV infection-associated pathology is haemorrhagic fever, which often leads to a fatal shock-like syndrome (DHF/DSS) owing to an increase in vascular endothelial permeability. Here, we show, in a viral dose-dependent manner, that DV-infected immature dendritic cells overproduce soluble gelatinolytic matrix metalloproteinase (MMP)-9-and to a lesser extent MMP-2-which enhances endothelial permeability, but which are reduced by specific inhibitors and a neutralizing anti-MMP-9 antibody. This permeability was associated with a loss of expression of the platelet endothelial adhesion molecule 1 (PECAM-1) and vascular endothelium (VE)-cadherin cell adhesion molecules and redistribution of F-actin fibres. These in vitro observations were confirmed in an in vivo vascular-leakage mouse model. These results provide a molecular basis for DHF/DSS that could be a basis for a general model of haemorrhagic fever-inducing viruses, and identify a new therapeutic approach for the treatment of viral-induced vascular leakage by specifically targeting gelatinolytic metalloproteases.

Dengue‐virus‐infected dendritic cells trigger vascular leakage through metalloproteinase overproduction

Dengue virus (DV) is an important re-emerging arthropod-borne virus of global significance. The defining characteristic of DV infection-associated pathology is haemorrhagic fever, which often leads to a fatal shock-like syndrome (DHF/DSS) owing to an increase in vascular endothelial permeability. Here, we show, in a viral dose-dependent manner, that DV-infected immature dendritic cells overproduce soluble gelatinolytic matrix metalloproteinase (MMP)-9-and to a lesser extent MMP-2-which enhances endothelial permeability, but which are reduced by specific inhibitors and a neutralizing anti-MMP-9 antibody. This permeability was associated with a loss of expression of the platelet endothelial adhesion molecule 1 (PECAM-1) and vascular endothelium (VE)-cadherin cell adhesion molecules and redistribution of F-actin fibres. These in vitro observations were confirmed in an in vivo vascular-leakage mouse model. These results provide a molecular basis for DHF/DSS that could be a basis for a general model of haemorrhagic fever-inducing viruses, and identify a new therapeutic approach for the treatment of viral-induced vascular leakage by specifically targeting gelatinolytic metalloproteases.