Expression Of Junctional Adhesion Molecule Research Articles

Xylanase and beta-glucanase improve performance parameters and footpad dermatitis and modulate intestinal microbiota in broilers under an Eimeria challenge

Coccidiosis is an enteric disease of poultry worldwide that compromises gut health and growth performance. The current research investigated the effects of 2 doses of a multienzyme preparation on broilers' performance, gut health, and footpad dermatitis (FPD) under an Eimeria challenge. A total of 512 mixed-sex day-old chicks (Cobb 500) were randomly allocated to 4 treatments of 8 replicates. Treatments were: 1) nonchallenged control (NC); 2) NC+Eimeria challenge (CC); 3) CC+recommended level of xylanase and glucanase (XG, 100 g/t feed [on top]); 4) CC+double XG (2XG, 200 g/t feed). Eimeria spp. vaccine strains were gavaged on d 9 to induce coccidiosis in chickens. Performance parameters were evaluated during starter, grower, and finisher phases, and 4 birds per pen were euthanized on d 16 for sampling, FPD was scored on d 35, and litter moisture was analyzed on d 17 and 35. The data were analyzed using 1-way ANOVA with Tukey's test to separate means, and Kruskal-Wallis test was used for non-normally distributed parameters. The results showed that the Eimeria challenge was successful based on reduced weight gain and feed intake during grower phase, and higher FITC-d concentration, lesion score (female), and oocyst counts (d 14) in CC group compared to N.C. group, while XG and 2XG increased (P < 0.001) weight gain and improved FCR compared to CC and NC groups during finisher phase. The addition of X.G. and 2XG decreased litter moisture (P=0.003) and FPD (P < 0.001) in challenged broilers compared to the N.C. group (d 35). Supplementing XG and 2XG reestablished the population of Lactobacillus in the cecum of challenged birds to an intermediate level between the NC and CC groups (P > 0.05). The inclusion of XG tended to increase the expression of Junctional adhesion molecule 2 (JAM2), which was not different from CC and NC groups (P > 0.05). In conclusion, the combination of xylanase and glucanase (Natugrain TS) improved the performance and modulated jejunal microbiota of broilers under mild Eimeria challenge.

The effects of oregano essential oil on production performance and intestinal barrier function in growing Hyla rabbits

The purpose of this study was to investigate the effects of oregano essential oil on the production performance and intestinal barrier in rabbits. One hundred and ninety-two weaned Hyla rabbits (35 days old) with similar body weight (1268.5 ± 25 g) were randomly divided into four groups (24 replicates per group, two rabbits per replicate): fed a basal diet (Control group), fed a basal diet containing 0.02% oregano essential oil (LO group, the purity of oregano essential oil was 5%), fed a basal diet containing 0.04% oregano essential oil (MO group), or fed a basal diet containing 0.08% oregano essential oil (HO group). The trial included 7 days of adaptation and 23 days of testing. Although dietary addition of oregano essential oil did not affect significantly the average daily body weight and final body weight (p > .05), dietary addition of 0.08% oregano essential oil decreased significantly feed intake and diarrhoea rate of the rabbits (p < .05). When the addition of oregano essential oil in the feed reached 0.08%, the Villus high/Crypt depth value in the ileum of meat rabbits increased significantly (p < .05). Dietary addition of 0.08% oregano essential oil increased significantly the gene expression of junctional adhesion molecule 2 (JAM2) and JAM3 in jejunum (p < .05). The content of interleukin-2 (IL-2) and immunoglobulin A (SIgA) in jejunum and IL-10 and secretory immunoglobulin G (SIgG) in ileum were significantly increased after the addition of 0.08% oregano essential oil compared with the control (p < .05). In conclusion, a dietary supplement of oregano essential oil modulates immune responses and enhances the intestinal barrier. Besides, our experiment offers positive evidence in improving rabbit health of oregano essential oil instead of antibiotics. HIGHLIGHTS Oregano essential oil can improve the production performance of rabbits. Oregano essential oil improved intestinal barrier function in rabbits. Oregano essential oil can be used as a new additive in rabbit feed.

Single-cell RNA sequencing of equine mesenchymal stromal cells from primary donor-matched tissue sources reveals functional heterogeneity in immune modulation and cell motility

BackgroundThe efficacy of mesenchymal stromal cell (MSC) therapy is thought to depend on the intrinsic heterogeneity of MSC cultures isolated from different tissue sources as well as individual MSCs isolated from the same tissue source, neither of which is well understood. To study this, we used MSC cultures isolated from horses. The horse is recognized as a physiologically relevant large animal model appropriate for translational MSC studies. Moreover, due to its large size the horse allows for the simultaneous collection of adequate samples from multiple tissues of the same animal, and thus, for the unique collection of donor matched MSC cultures from different sources. The latter is much more challenging in mice and humans due to body size and ethical constraints, respectively.MethodsIn the present study, we performed single-cell RNA sequencing (scRNA-seq) on primary equine MSCs that were collected from three donor-matched tissue sources; adipose tissue (AT), bone marrow (BM), and peripheral blood (PB). Based on transcriptional differences detected with scRNA-seq, we performed functional experiments to examine motility and immune regulatory function in distinct MSC populations.ResultsWe observed both inter- and intra-source heterogeneity across the three sources of equine MSCs. Functional experiments demonstrated that transcriptional differences correspond with phenotypic variance in cellular motility and immune regulatory function. Specifically, we found that (i) differential expression of junctional adhesion molecule 2 (JAM2) between MSC cultures from the three donor-matched tissue sources translated into altered cell motility of BM-derived MSCs when RNA interference was used to knock down this gene, and (ii) differences in C-X-C motif chemokine ligand 6 (CXCL6) expression in clonal MSC lines derived from the same tissue source correlated with the chemoattractive capacity of PB-derived MSCs.ConclusionsUltimately, these findings will enhance our understanding of MSC heterogeneity and will lead to improvements in the therapeutic potential of MSCs, accelerating the transition from bench to bedside.

CircKIF4A sponges miR-127 to promote ovarian cancer progression.

Ovarian cancer is a major gynecologic cancer and common cause of gynecologic cancer death worldwide. However, the molecular mechanisms of ovarian cancer progression are still unclear. circular RNAs (circRNAs) are recently reported to be involved in cancer progression regulation but the potential functions of circRNAs in ovarian cancer remains unknown. In this study, we explored the expression of circKIF4A in ovarian cancer tissues. Then, a series of experiments were conducted to investigate how circKIF4A functioned in ovarian cancer in vitro and in vivo. The results revealed that circKIF4A was highly expressed in ovarian cancer tissues. Knockdown of circKIF4A suppressed cell proliferation and migration in ovarian cancer. Subsequent mechanism study revealed that circKIF4A acted as a competitive endogenous RNA (ceRNA) to promoted ovarian cancer progression by sponging miR-127 and upregulated the expression of Junctional adhesion molecule 3 (JAM3). Therefore, circKIF4A could be a novel biomarker and therapeutic target for ovarian cancer.

The effects of dietary Bacillus subtilis supplementation, as an alternative to antibiotics, on growth performance, intestinal immunity, and epithelial barrier integrity in broiler chickens infected with Eimeria maxima

The objective of this study was to investigate the effects of dietary Bacillus subtilis supplementation on growth performance, jejunal lesion scores, oocyst shedding, and cytokine and tight junction protein expression in broiler chickens infected with Eimeria maxima. A total of 196 male day-old Ross 708 broilers were given a nonexperimental diet until 14 D of age. Then, all chickens were randomly assigned to one of seven dietary treatments: 2 basal diets (CON and NC); CON + virginiamycin (AB1); CON + bacitracin methylene disalicylate (BMD; AB2); CON + B. subtilis 1781 (PB1); CON + B. subtilis 747 (PB2); or CON + B. subtilis 1781 + 747 (PB3). At day 21, all chickens except those in the CON group were orally inoculated with E. maxima oocysts. At 7 D after E. maxima infection, the body weight gains of chickens fed PB2 and PB3 increased (P = 0.032) as much as those in chickens fed AB2. The body weight gain and feed efficiency of chickens fed PB2 were significantly increased (P < 0.001), and PB2 chickens showed (P = 0.005) the lowest lesion scores after E. maxima infection. Chickens fed PB2 showed (P < 0.05) lower mRNA expression of IL-1β in infected chicken groups. Chickens in the AB1, AB2, PB1, PB2, and PB3 groups showed (P < 0.05) greater mRNA expression of junctional adhesion molecule 2 in jejunal tissue, whereas occludin expression increased (P < 0.05) in the jejunal tissue of chickens fed AB2 or PB2. Dietary B. subtilis supplementation significantly improved the growth performance of young chickens to a level comparable with that induced by virginiamycin or BMD without E. maxima infection. After infection with E. maxima, dietary virginiamycin and BMD significantly enhanced the epithelial barrier integrity, and the dietary B. subtilis 747 showed significantly enhanced growth performance, intestinal immunity, and epithelial barrier integrity. Together our results indicated that certain strains of B. subtilis provide beneficial effects on the growth of young broiler chickens and have the potential to replace antibiotic growth promoters.

Dietary addition of garlic straw improved the intestinal barrier in rabbits1.

Weanling rabbits frequently exhibit diarrhea or flatulence. Our experiment was conducted to investigate the effect of garlic straw on the performance and intestinal barrier of rabbits. Hyla rabbits (60 d, n = 160) with similar body weight were divided into 4 groups (4 replicates per group and 10 rabbits per replicate): fed a basal diet (control) or fed an experimental diet with 5%, 10%, or 15% garlic straw powder supplement. The results showed that the dietary addition of garlic straw increased significantly the average daily gain and average daily feed intake. Compared with the control, dietary addition of 10% and 15% garlic straw decreased significantly the death rate of rabbit. Rabbits in 10% garlic straw group had a higher secretory immunoglobulins A and immunoglobulins G concentration in jejunum and ileum than control while lower tumor necrosis factor α (TNFα) concentration in jejunum. Compared with the control, dietary addition of 10% garlic straw increased significantly genes expression of zonula occluden protein 2 (ZO2) in jejunum and ileum and mucin4 in ileum while did not alter the genes expression of junctional adhesion molecule 2 (JAM2), JAM3, ZO1, occluding, claudin1, mucin1, mucin6, and toll-like receptor 4 in jejunum and ileum and mucin4 in jejunum. In conclusion, dietary supplement of garlic straw modulates immune responses and enhances intestinal barrier, meanwhile inhibits the synthesis of pro-inflammatory cytokine of TNFα. Besides, our experiment offers positive evidence in improving rabbit health of garlic instead of antibiotics.

Junctional adhesion molecules JAM-B and JAM-C promote autoimmune-mediated liver fibrosis in mice

Fibrosis remains a serious health concern in patients with chronic liver disease. We recently reported that chemically induced chronic murine liver injury triggers increased expression of junctional adhesion molecules (JAMs) JAM-B and JAM-C by endothelial cells and de novo synthesis of JAM-C by hepatic stellate cells (HSCs). Here, we demonstrate that biopsies of patients suffering from primary biliary cholangitis (PBC), primary sclerosing cholangitis (PSC) or autoimmune hepatitis (AIH) display elevated levels of JAM-C on portal fibroblasts (PFs), HSCs, endothelial cells and cholangiocytes, whereas smooth muscle cells expressed JAM-C constitutively. Therefore, localization and function of JAM-B and JAM-C were investigated in three mouse models of autoimmune-driven liver inflammation. A PBC-like disease was induced by immunization with 2-octynoic acid-BSA conjugate, which resulted in the upregulation of both JAMs in fibrotic portal triads. Analysis of a murine model of PSC revealed a role of JAM-C in PF cell-cell adhesion and contractility. In mice suffering from AIH, endothelial cells increased JAM-B level and HSCs and capsular fibroblasts became JAM-C-positive. Most importantly, AIH-mediated liver fibrosis was reduced in JAM-B−/− mice or when JAM-C was blocked by soluble recombinant JAM-C. Interestingly, loss of JAM-B/JAM-C function had no effect on leukocyte infiltration, suggesting that the well-documented function of JAMs in leukocyte recruitment to inflamed tissue was not effective in the tested chronic models. This might be different in patients and may even be complicated by the fact that human leukocytes express JAM-C. Our findings delineate JAM-C as a mediator of myofibroblast-operated contraction of the liver capsule, intrahepatic vasoconstriction and bile duct stricture. Due to its potential to interact heterophilically with endothelial JAM-B, JAM-C supports also HSC/PF mural cell function. Together, these properties allow JAM-B and JAM-C to actively participate in vascular remodeling associated with liver/biliary fibrosis and suggest them as valuable targets for anti-fibrosis therapies.

Junctional Adhesion Molecule 2 Represents a Novel Subset of Hematopoietic Stem Cells Poised for T Lymphopoiesis

Phenotypically well-characterized hematopoietic stem cells (HSCs) still represent a heterogeneous pool of primitive cells regarding to their functionality. In particular, different lineage potential of HSCs have been considered as one of key features of the HSC heterogeneity. The lineage output of HSCs is often coupled with cell cycle status or long-term reconstitution potential, however molecular mechanisms of the mutuality are unclear and other type of the regulation may exist. In addition, prospective isolation of such HSCs biased towards specific lineage(s) is still problematic, as many of categorizations highly rely on retrospective information, e.g. transplantation assay. Although several markers have been reported to be able to subdivide HSCs into subcategories, exploration of additional markers will allow us understanding further molecular mechanisms of HSC regulations including activation and lineage choice.Here, we show that cell surface expression of Junctional adhesion molecule 2 (Jam2) represents higher reconstitution capacity of HSCs and the T cell potential. Flow cytometry analyses revealed that a subset of CD150+CD48-KSL cells in mouse bone marrow (BM) were positive for Jam2 (Jam2+HSC, 36.6 ±13.0 %), while other Jam family member Jam1 (F11r) was expressed on all HSCs and Jam3 was not detected. To examine functional differences of Jam2+ and Jam2-HSCs, 30 cells were separately transplanted into lethally irradiated mice. Peripheral blood analyses revealed that Jam2+HSCs reconstituted more efficiently than Jam2-HSCs (77.5 ±15.9 and 51.7 ±29.3 %, respectively). In case of transplantation using 5 cells, the frequency of reconstituted mice was higher in Jam2+HSCs (7 in 11) compared to Jam2-HSCs (4 in 11), indicating that Jam2+ population is more enriched for functional HSCs. The expression of Jam2 on HSC is reversible, but not hierarchical, as both Jam2+ and Jam2-HSCs reconstituted opposite population in the BM.Lineage analyses revealed that Jam2+HSCs have a greater potential in lymphoid cell reconstitution, particularly T cells, whereas the chimerism in myeloid cells was not significantly different from Jam2-HSCs. This tendency of higher contribution to the T cell development was even more pronounced in the secondary transplantation experiments, where the contribution of Jam2+HSCs in T cells was close to 100 %. Of note, most of Jam2+HSCs were in a dormant state, suggesting that the T cell (or lymphoid) potential of Jam2+HSCs is independent of cell cycle progression.Jam2 has been reported to interact with Jam1, which mediates the Notch signaling (Kobayashi et al., Nature, 2014). Competitive co-culture of Jam2+ vs Jam2-HSCs on OP9-DL1 showed that Jam2+HSCs dominated the T cell production, whereas no difference was seen in B cell production upon OP9 co-culture. Since Jam2 positivity correlates to T cell potential, we asked if altered T lymphopoiesis environment affects the cell surface Jam2 expression. Comparison of C57BL/6, NOD, NOD-Scid and NOD-Scid Il2rγ KO (NSG) mice showed that HSCs of NSG mice have significantly higher frequency of Jam2+HSCs, suggesting that cell surface Jam2 expression might be regulated by specific cytokine(s) binding to IL2Rγ.Our findings suggest Jam2 is a new marker for a subset of HSCs that preferentially generate T cells. In addition, this work uncouples the lineage choice and cell cycle status, which proposes a novel model to the lineage-determining machineries. Since efficient and immediate generation of T cells in transplantation therapy is important to minimize infectious risks, understanding the molecular basis of the Jam-Notch cooperation would contribute to establish safer and more efficient treatment. DisclosuresNo relevant conflicts of interest to declare.

Differential mouse-strain specific expression of Junctional Adhesion Molecule (JAM)-B in placental structures

ABSTRACTThe junctional adhesion molecule (JAM)-B, a member of the immunoglobulin superfamily, is involved in stabilization of interendothelial cell-cell contacts, formation of vascular tubes, homeostasis of stem cell niches and promotion of leukocyte adhesion and transmigration. In the human placenta, JAM-B protein is abundant and mRNA transcripts are enriched in first-trimester extravillous trophoblast in comparison to the villous trophoblast. We here aimed to elucidate the yet unexplored spatio-temporal expression of JAM-B in the mouse placenta. We investigated and semi-quantified JAM-B protein expression by immunohistochemistry in early post-implantation si tes and in mid- to late gestation placentae of various murine mating combinations. Surprisingly, the endothelium of the placental labyrinth was devoid of JAM-B expression. JAM-B was mainly present in spongiotrophoblast cells of the junctional zone, as well as in the fetal vessels of the chorionic plate, the umbilical cord and in maternal myometrial smooth muscle. We observed a strain-specific placental increase of JAM-B protein expression from mid- to late gestation in Balb/c-mated C57BL/6 females, which was absent in DBA/2J-mated Balb/c females. Due to the essential role of progesterone during gestation, we further assessed a possible modulation of JAM-B in mid-gestational placentae deficient in the progesterone receptor (Pgr−/−) and observed an increased expression of JAM-B in Pgr−/− placentae, compared to Pgr+/+ tissue samples. We propose that JAM-B is an as yet underappreciated trophoblast lineage-specific protein, which is modulated via the progesterone receptor and shows unique strain-specific kinetics. Future work is needed to elucidate its possible contribution to placental processes necessary to ensuring its integrity, ultimately facilitating placental development and fetal growth.

Increased Bacterial Invasion and Differential Expression of Tight‐Junction Proteins, Growth Factors, and Growth Factor Receptors in Periodontal Lesions

Many pathogens are known to modulate epithelial physical barriers, particularly tight-junction (TJ) proteins, to enter host cells and/or tissues. Growth factors have been implicated in the regulation of TJ proteins. The aim of this study is to determine differences in the levels of TJ proteins, growth factors, and their receptors in relation to bacterial invasion in diseased gingival tissues obtained from patients with periodontitis. The presence of bacteria and expression of junctional adhesion molecule (JAM)-A, occludin, epidermal growth factor (EGF), keratinocyte growth factor (KGF), insulin-like growth factor-I (IGF-I), EGF receptor, KGF receptor, and IGF-1 receptor (IGF-1R) were evaluated in gingival tissues from healthy (n = 10) and diseased (n = 10) sites in patients with periodontitis by in situ hybridization and immunohistochemistry. The bacterial invasion of gingival tissue was increased in periodontal lesions compared with healthy sites. Although the levels of JAM-A and occludin were not significantly different between the healthy and diseased sites, aberrant cytoplasmic expression of JAM-A and occluding was often observed in the lesions. In addition, more leukocytes expressing JAM-A or occludin were observed within the disease-associated epithelia. Compared with the healthy sites, the differential expression of KGF, IGF-I, and IGF-1R was observed in the periodontal lesions. The levels of TJ proteins showed positive correlations with those of growth factors. The aberrant expression of growth factors and TJ proteins may contribute to increased bacterial invasion and disease progression in periodontal lesions.

Low junctional adhesion molecule A expression correlates with poor prognosis in gastric cancer

BackgroundThe aberrant expression of junctional adhesion molecule A (JAM-A), which has a close correlation with the development, progression, metastasis, and prognosis of cancer, has been frequently reported. However, neither JAM-A expression nor its correlation with clinicopathologic variables and patient survival has been defined in gastric cancers. Moreover, little is known about the role of JAM-A in gastric cancer progression. We carried out the present study to investigate the prognostic value of JAM-A expression in gastric cancer patients. Furthermore, the biological roles of JAM-A in gastric cancer progression were also investigated. MethodsWe determined JAM-A expression in 167 primary gastric cancer tissues and 94 matched adjacent non-tumor tissues by immunohistochemistry. Transwell migration assays and matrigel invasion assays were used to explore the role of JAM-A in gastric cancer cells migration and invasion. CCK-8 assays were used to examine the effect of JAM-A on the proliferation of gastric cancer cells. ResultsJAM-A was downregulated in gastric cancer tissues. Low JAM-A expression was significantly associated with tumor size, lymphatic vessel invasion, lymph node metastasis, and TNM stage. Low JAM-A expression was also significantly associated with poor disease-specific survival in gastric cancer patients. Multivariate analysis demonstrated low JAM-A expression as an independent factor predicting poor survival. In addition, JAM-A had the effect on inhibition of gastric cancer cells migration and invasion. However, JAM-A had no significant effects on proliferation of gastric cancer cells. ConclusionsLow JAM-A expression correlates with poor clinical outcome and promotes cell migration and invasion in gastric cancer.

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

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

Bifidobacteria Isolated From Infants and Cultured on Human Milk Oligosaccharides Affect Intestinal Epithelial Function

Human milk oligosaccharides (HMOs) are the third most abundant component of breast milk. Our laboratory has previously revealed gene clusters specifically linked to HMO metabolism in selected bifidobacteria isolated from fecal samples of infants. Our objective was to test the hypothesis that growth of selected bifidobacteria on HMO stimulates the intestinal epithelium. Caco-2 and HT-29 cells were incubated with lactose (LAC)- or HMO-grown Bifidobacterium longum subsp infantis (B infantis) or B bifidum. Bacterial adhesion and translocation were measured by real-time quantitative polymerase chain reaction. Expression of pro- and anti-inflammatory cytokines and tight junction proteins was analyzed by real-time reverse transcriptase. Distribution of tight junction proteins was measured using immunofluorescent microscopy. We showed that HMO-grown B infantis had a significantly higher rate of adhesion to HT-29 cells compared with B bifidum. B infantis also induced expression of a cell membrane glycoprotein, P-selectin glycoprotein ligand-1. Both B infantis and B bifidum grown on HMO caused less occludin relocalization and higher expression of anti-inflammatory cytokine, interleukin-10 compared with LAC-grown bacteria in Caco-2 cells. B bifidum grown on HMO showed higher expression of junctional adhesion molecule and occludin in Caco-2 cells and HT-29 cells. There were no significant differences between LAC or HMO treatments in bacterial translocation. The study provides evidence for the specific relation between HMO-grown bifidobacteria and intestinal epithelial cells. To our knowledge, this is the first study describing HMO-induced changes in the bifidobacteria-intestinal cells interaction.

Low Expression of Junctional Adhesion Molecule A Is Associated with Metastasis and Poor Survival in Pancreatic Cancer

Characterized by its highly aggressive tumor biology, pancreatic cancer still remains a fatal diagnosis. The junctional adhesion molecule A (JAM-A) is a type I transmembrane glycoprotein, which recently has been shown to affect the prognosis of several human malignancies. JAM-A antigen expression was investigated retrospectively by immunohistochemistry in paraffin-embedded primary tumor tissue samples from a series (n = 186) of consecutive patients with pancreatic adenocarcinoma. Survival was calculated by Kaplan-Meier curves. Parameters found to be of prognostic significance in univariate analysis were verified in a multivariate Cox regression model. Low expression of JAM-A was observed in 79 (42 %) of 186 pancreatic cancer specimens and was significantly associated with poor overall survival (P < 0.01). By univariate analysis, low expression of JAM-A was found to correlate with positive lymph node status (P = 0.02), the presence of distant metastasis (P = 0.05), and tumor grade (P = 0.04), suggesting it may be an important event involved in cancer progression. Furthermore, in the subgroup of patients with surgically resected pancreatic cancer, low expression of JAM-A significantly correlated with decreased progression-free survival (P < 0.01). Multivariate analysis revealed JAM-A to be an independent predictor of poor outcome. These findings suggest for the first time that low levels of JAM-A expression in pancreatic cancer are associated with poor clinical outcome. JAM-A may represents a target molecule for functional inactivation and serve as a novel biomarker of adverse prognosis in pancreatic cancer.

Differential expression of junctional adhesion molecules in different stages of systemic sclerosis: pathogenetic implications

Systemic sclerosis (SSc, scleroderma) 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. In the present study, we investigated the possible role of JAMs in SSc pathogenesis.The expression of JAM-A and JAM-C in skin biopsies from 25 patients with SSc (14 early-stage SSc, 11 late-stage SSc) and 15 healthy subjects was investigated by immunohistochemistry and western blotting. Subcellular localization of JAMs in cultured dermal healthy MVECs (H-MVECs) and early-stage SSc-MVECs was assessed by confocal laser scanning microscopy. Serum levels of soluble JAM-A (sJAM-A) and JAM-C (sJAM-C) from 64 SSc patients (25 early-stage SSc, 39 late-stage SSc) and 32 healthy subjects were examined by ELISA.In control skin, constitutive JAM-A expression was observed in dermal MVECs and fibroblasts. In early-stage SSc skin, JAM-A expression was strongly increased in MVECs, fibroblasts and perivascular infiltrating inflammatory cells. In late-stage SSc, JAM-A expression was decreased compared with healthy controls. JAM-C was weakly expressed in control and latestage SSc skin, while it was strongly expressed in MVECs, fibroblasts and inflammatory cells from early-stage SSc skin. Cell surface expression of JAM-A was higher in early-stage SSc-MVECs and increased in H-MVECs upon stimulation with early-stage SSc sera. JAM-C was cytoplasmic in resting H-MVECs, while it was rapidly recruited to the cell surface upon challenging with early-stage SSc sera. Early-stage SSc-MVECs exhibited increased expression and constitutive localization of JAM-C on the cell surface. Circulating levels of sJAM-A and sJAM-C were significantly increased in earlystage SSc compared with healthy controls and late-stage SSc. In addition, sJAM-A and sJAM-C levels were significantly raised in SSc patients with ‘early/active’ nailfold capillaroscopic pattern compared with those with ‘late’ capillaroscopic pattern. Collectively, the results of our study suggest that JAMs may participate in dermal MVEC activation, inflammatory processes and impaired angiogenesis in different stages of SSc.

The junctional adhesion molecule JAM-C regulates polarized transendothelial migration of neutrophils in vivo

Neutrophil migration into inflamed tissues is a fundamental component of innate immunity. A decisive step in this process is the polarised migration of blood neutrophils through endothelial cells (ECs) lining the venular lumen (transendothelial cell migration; TEM) in a luminal to abluminal direction. Using real-time confocal imaging we report that neutrophils can exhibit disrupted polarised TEM (“hesitant” and “reverse”) in vivo. These events were noted in inflammation following ischemia-reperfusion injury, characterised by reduced expression of junctional adhesion molecule C (JAM-C) from EC junctions, and were enhanced by EC JAM-C blockade or genetic deletion. The results identify JAM-C as a key regulator of polarised neutrophil TEM in vivo and suggest that reverse TEM neutrophils can contribute to dissemination of systemic inflammation.

Differential expression of junctional adhesion molecules in systemic sclerosis (SSc) skin

ObjectiveJunctional adhesion molecule (JAM)-A and JAM-C regulate leucocyte-endothelial cell (EC) interactions. JAMs also interact at inter-EC junctions regulating vascular permeability and are implicated in pathophysiological processes involving leucocyte transmigration, tight...

Expression of junctional adhesion molecules on the human lymphatic endothelium

Human lymphatic vessels express several leukocyte adhesion molecules. The study here investigated the expression of three junctional adhesion molecules (JAM) which are a newly reported glycoprotein family of adhesion molecules on human lymphatic endothelium. In this study, JAM-1 and JAM-3 but not JAM-2 were detected in cultured human neonatal dermal lymphatic endothelial cells (LEC) at the gene and protein levels by microarray, RT-PCR, real-time PCR, and immunohistochemical analysis. The JAM-1 and JAM-3 expression was not altered in the TNF-α-treated LEC or in the untreated cells. In human tissue, the expression of JAM-1, and the expression of JAM-1, JAM-2, and JAM-3 were observed in collecting lymphatic vessels of uninflamed small intestine, and in initial lymphatics of inflamed tongue and uninflamed gingival tissue. It is thought that JAM-2 mRNA could be produced in mature vascular endothelium but not in cultured cells, and that human intestinal and oral lymphatic vessels usually express JAM-1, JAM-2, and JAM-3. There were initial lymphatics simultaneously expressing JAM-1, JAM-2, and JAM-3 in the mucosal connective tissue papillae of gingival tissue. The three JAM expressions on the lymphatic endothelium may contribute to both seal the cell–cell contact at interendothelial junctions and also allow lymphocytes to transmigrate into lymphatic vessels from tissue, independent of inflammatory cytokines.

The uremic solute p-cresol decreases leukocyte transendothelial migration in vitro

Chronic renal failure (CRF) patients display an immunodeficiency state, and uremic solutes that accumulate during CRF may be involved in this immunodeficiency. In this study, we examined whether the uremic solute para-cresol (p-cresol), at concentrations similar to those found in patients, alters leukocyte transmigration in vitro. We found that p-cresol significantly inhibited monocyte THP-1 cell line and PBMCs transmigration across IL-1beta-stimulated human umbilical vein endothelial cell (HUVEC) in a static two-compartment model. This inhibitory effect of p-cresol persisted in the presence of a physiologic concentration of human serum albumin. In order to investigate the mechanism involved, expression of endothelial chemokines, fractalkine, monocyte chemoattractant protein 1 (MCP-1) and IL-8 and membrane expression of junctional adhesion molecule A (JAM-A or JAM-1) were studied. We found that p-cresol decreased mRNA expression of the chemokine fractalkine in IL-1beta-stimulated HUVEC, without modifying mRNA expression of MCP-1 and IL-8. In addition, p-cresol decreased IL-1beta-induced expression of membrane-bound and soluble forms of fractalkine and impaired the membrane expression of JAM-A. Taken together, these results suggest that p-cresol, by impairing leukocyte transendothelial migration, plays a role in the immune dysfunction of uremic patients.

Conjugated linoleic acid enhances transepithelial calcium transport in human intestinal-like Caco-2 cells: An insight into molecular changes

Conjugated linoleic acid (CLA) has been shown to enhance paracellular and transcellular Ca transport across human intestinal-like Caco-2 cell monolayers. The mechanisms of action, however, are still unclear. Therefore, this study investigated the molecular mechanisms underlying CLA-induced stimulation of Ca transport by use of preliminary microarray data together with more detailed and comprehensive quantitative reverse transcriptase-PCR analysis. While molecular expression of junctional adhesion molecule (JAM), ZO-2, ZO-3, claudin 2 and claudin 3 were unaltered, ZO-1, occludin, and claudin 4 were all up-regulated (1.6, 1.6, 2.4-fold, respectively; P < 0.001 – 0.01 ) and claudin 1 down-regulated (2.5-fold; P < 0.05 ) by trans-10, cis-12 CLA, which may underpin its effects on tight-junction function and paracellular Ca transport. On the other hand, expression of key genes involved in transcellular Ca transport (CaT1, ECaC1, calbindin D 9k, vitamin D receptor and PMCA) were unaffected by trans-10, cis-12 CLA. The mechanism by which CLA enhances transcellular Ca transport remains unclear.