VE-PTP maintains the endothelial barrier via plakoglobin and becomes dissociated from VE-cadherin by leukocytes and by VEGF

We have shown recently that vascular endothelial protein tyrosine phosphatase (VE-PTP), an endothelial-specific membrane protein, associates with vascular endothelial (VE)-cadherin and enhances VE-cadherin function in transfected cells (Nawroth, R., G. Poell, A. Ranft, U. Samulowitz, G. Fachinger, M. Golding, D.T. Shima, U. Deutsch, and D. Vestweber. 2002. EMBO J. 21:4885-4895). We show that VE-PTP is indeed required for endothelial cell contact integrity, because down-regulation of its expression enhanced endothelial cell permeability, augmented leukocyte transmigration, and inhibited VE-cadherin-mediated adhesion. Binding of neutrophils as well as lymphocytes to endothelial cells triggered rapid (5 min) dissociation of VE-PTP from VE-cadherin. This dissociation was only seen with tumor necrosis factor alpha-activated, but not resting, endothelial cells. Besides leukocytes, vascular endothelial growth factor also rapidly dissociated VE-PTP from VE-cadherin, indicative of a more general role of VE-PTP in the regulation of endothelial cell contacts. Dissociation of VE-PTP and VE-cadherin in endothelial cells was accompanied by tyrosine phoshorylation of VE-cadherin, beta-catenin, and plakoglobin. Surprisingly, only plakoglobin but not beta-catenin was necessary for VE-PTP to support VE-cadherin adhesion in endothelial cells. In addition, inhibiting the expression of VE-PTP preferentially increased tyrosine phosphorylation of plakoglobin but not beta-catenin. In conclusion, leukocytes interacting with endothelial cells rapidly dissociate VE-PTP from VE-cadherin, weakening endothelial cell contacts via a mechanism that requires plakoglobin but not beta-catenin.

Alkylamides from Echinacea are a new class of cannabinomimetics. Cannabinoid type 2 receptor-dependent and -independent immunomodulatory effects

Alkylamides (alkamides) from Echinacea modulate tumor necrosis factor alpha mRNA expression in human monocytes/macrophages via the cannabinoid type 2 (CB2) receptor (Gertsch, J., Schoop, R., Kuenzle, U., and Suter, A. (2004) FEBS Lett. 577, 563-569). Here we show that the alkylamides dodeca-2E,4E,8Z,10Z-tetraenoic acid isobutylamide (A1) and dodeca-2E,4E-dienoic acid isobutylamide (A2) bind to the CB2 receptor more strongly than the endogenous cannabinoids. The Ki values of A1 and A2 (CB2 approximately 60 nM; CB1 >1500 nM) were determined by displacement of the synthetic high affinity cannabinoid ligand [3H]CP-55,940. Molecular modeling suggests that alkylamides bind in the solvent-accessible cavity in CB2, directed by H-bonding and pi-pi interactions. In a screen with 49 other pharmacologically relevant receptors, it could be shown that A1 and A2 specifically bind to CB2 and CB1. A1 and A2 elevated total intracellular Ca2+ in CB2-positive but not in CB2-negative promyelocytic HL60 cells, an effect that was inhibited by the CB2 antagonist SR144528. At 50 nM, A1, A2, and the endogenous cannabinoid anandamide (CB2 Ki >200 nM) up-regulated constitutive interleukin (IL)-6 expression in human whole blood in a seemingly CB2-dependent manner. A1, A2, anandamide, the CB2 antagonist SR144528 (Ki <10 nM), and also the non-CB2-binding alkylamide undeca-2E-ene,8,10-diynoic acid isobutylamide all significantly inhibited lipopolysaccharide-induced tumor necrosis factor alpha, IL-1beta, and IL-12p70 expression (5-500 nM) in a CB2-independent manner. Alkylamides and anandamide also showed weak differential effects on anti-CD3-versus anti-CD28-stimulated cytokine expression in human whole blood. Overall, alkylamides, anandamide, and SR144528 potently inhibited lipopolysaccharide-induced inflammation in human whole blood and exerted modulatory effects on cytokine expression, but these effects are not exclusively related to CB2 binding.

Predictors of inflammation in response to anthracycline-based chemotherapy for breast cancer

Although chemotherapy for breast cancer can increase inflammation, few studies have examined predictors of this phenomenon. This study examined potential contributions of demographics, disease characteristics, and treatment regimens to markers of inflammation in response to chemotherapy for breast cancer. Thirty-five women with stage I-III-A breast cancer (mean age 50 years) were studied prior to cycle 1 and prior to cycle 4 of anthracycline-based chemotherapy. Circulating levels of inflammatory markers with high relevance to breast cancer were examined, including C-reactive protein (CRP), tumor necrosis factor-alpha (TNF-alpha), Interleukin-1 receptor antagonist (IL1-RA), vascular endothelial growth factor (VEGF), soluble intercellular adhesion molecule-1 (sICAM-1), Interleukin- (IL-6), soluble P-selectin (sP-selectin), and von Willebrand factor (vWf). Chemotherapy was associated with elevations in VEGF (p < or = 0.01), sICAM-1 (p < or = 0.01), sP-selectin (p < or = 0.02) and vWf (p < or = 0.05). Multiple regression analysis controlling for age and body mass index (BMI) showed that higher post-chemotherapy levels of inflammation were consistently related to higher pre-chemotherapy levels of inflammation (ps < or =0.05) as well as to certain disease characteristics. Post-chemotherapy IL-6 levels were higher in patients who had larger tumors (p < or = 0.05) while post-chemotherapy VEGF levels were higher in patients who had smaller tumors (p < or = 0.05). Post-chemotherapy sP-selectin levels were highest in women who had received epirubicin, cytoxan, 5-fluorouracil chemotherapy (p < or = 0.01). These findings indicate that chemotherapy treatment can be associated with elevations in certain markers of inflammation, particularly markers of endothelial and platelet activation. Inflammation in response to chemotherapy is most significantly related to inflammation that existed prior to chemotherapy but also potentially to treatment regimen and to certain disease characteristics.

Do common genetic variants in endotoxin signaling pathway contribute to predisposition to alcoholic liver cirrhosis?

BACKGROUND: Tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta), produced by endotoxin-activated Kupffer cells, play a key role in the pathogenesis of alcoholic liver cirrhosis (ALC). Alleles TNFA -238A, IL1B -31T and variant IL1RN*2 of repeat polymorphism in the gene encoding the IL-1 receptor antagonist increase production of TNF-alpha and IL-1beta, respectively. Alleles CD14 -159T, TLR4 c.896G and TLR4 c.1196T modify activation of Kupffer cells by endotoxin. We confirmed the published associations between these common variants and genetic predisposition to ALC by means of a large case-control association study conducted on two Central European populations. METHODS: The study population comprised a Czech sample of 198 ALC patients and 370 controls (MONICA project), and a German sample of 173 ALC patients and 331 controls (KORA-Augsburg), and 109 heavy drinkers without liver disease. RESULTS: Single locus analysis revealed no significant difference between patients and controls in all tested loci. Diplotype [IL1RN 2/ 2; IL1B -31T+] was associated with increased risk of ALC in the pilot study, but not in the validation samples. CONCLUSIONS: Although cytokine mediated immune reactions play a role in the pathogenesis of ALC, hereditary susceptibility caused by variants in the corresponding genes is low in Central European populations.

Marked improvement in nail psoriasis during treatment with adalimumab

BACKGROUND: Nail involvement is known as a common finding in psoriatic patients and represents a significant impact on patients' quality of life. The treatment of nail psoriasis is often challenging, and there is a need for new therapeutic options. Biologicals effective in the treatment of moderate to severe chronic plaque psoriasis may represent a new therapeutic modality for this disease. Adalimumab is a fully human IgG1 monoclonal antibody that binds to tumor necrosis factor alpha with high affinity and specificity. OBSERVATIONS: We report two cases of rapid improvement in nail psoriasis under adalimumab monotherapy with maintained effectiveness despite intermittent treatment as well as long remission after therapy discontinuation. CONCLUSION: The marked improvement of our two cases indicates that adalimumab may also help ameliorate nail psoriasis and warrants further controlled studies to establish the effectiveness and therapeutic regimes.

Programmed death 1 signaling on chronic myeloid leukemia-specific T cells results in T-cell exhaustion and disease progression

Chronic myeloid leukemia (CML) is a malignant myeloproliferative disease with a characteristic chronic phase (cp) of several years before progression to blast crisis (bc). The immune system may contribute to disease control in CML. We analyzed leukemia-specific immune responses in cpCML and bcCML in a retroviral-induced murine CML model. In the presence of cpCML and bcCML expressing the glycoprotein of lymphocytic choriomeningitis virus as a model leukemia antigen, leukemia-specific cytotoxic T lymphocytes (CTLs) became exhausted. They maintained only limited cytotoxic activity, and did not produce interferon-gamma or tumor necrosis factor-alpha or expand after restimulation. CML-specific CTLs were characterized by high expression of programmed death 1 (PD-1), whereas CML cells expressed PD-ligand 1 (PD-L1). Blocking the PD-1/PD-L1 interaction by generating bcCML in PD-1-deficient mice or by repetitive administration of alphaPD-L1 antibody prolonged survival. In addition, we found that PD-1 is up-regulated on CD8(+) T cells from CML patients. Taken together, our results suggest that blocking the PD-1/PD-L1 interaction may restore the function of CML-specific CTLs and may represent a novel therapeutic approach for CML.

The NF-{kappa}B negative regulator TNFAIP3 (A20) is inactivated by somatic mutations and genomic deletions in marginal zone lymphomas

Unique and shared cytogenetic abnormalities have been documented for marginal zone lymphomas (MZLs) arising at different sites. Recently, homozygous deletions of the chromosomal band 6q23, involving the tumor necrosis factor alpha-induced protein 3 (TNFAIP3, A20) gene, a negative regulator of NF-kappaB, were described in ocular adnexal MZL, suggesting a role for A20 as a tumor suppressor in this disease. Here, we investigated inactivation of A20 by DNA mutations or deletions in a panel of extranodal MZL (EMZL), nodal MZL (NMZL), and splenic MZL (SMZL). Inactivating mutations encoding truncated A20 proteins were identified in 6 (19%) of 32 MZLs, including 2 (18%) of 11 EMZLs, 3 (33%) of 9 NMZLs, and 1 (8%) of 12 SMZLs. Two additional unmutated nonsplenic MZLs also showed monoallelic or biallelic A20 deletions by fluorescent in situ hybridization (FISH) and/or SNP-arrays. Thus, A20 inactivation by either somatic mutation and/or deletion represents a common genetic aberration across all MZL subtypes, which may contribute to lymphomagenesis by inducing constitutive NF-kappaB activation.

Pregnancy in patients with ankylosing spondylitis: do regulatory T cells play a role?

OBJECTIVE: To investigate the numerical and functional changes of CD4+CD25(high) regulatory T (Treg) cells during pregnancy and postpartum in patients with ankylosing spondylitis (AS). METHODS: The frequency of CD4+CD25(high) T cells was determined by flow cytometry in 10 pregnant and 5 nonpregnant patients with AS as well as in 14 pregnant and 4 nonpregnant healthy controls. Pregnant individuals were investigated at the third trimester and 8 weeks postpartum. Treg cells and CD4+CD25- effector T (Teff) cells separated by fluorescence-activated cell sorting were stimulated with anti-CD3 and anti-CD28 monoclonal antibodies, alone or in coculture, to investigate proliferation and cytokine secretion. RESULTS: The frequency of CD4+CD25(high) Treg cells was significantly higher during pregnancy than postpartum in both healthy control subjects and patients with AS. In contrast to Treg cells in healthy pregnant women, Treg cells in pregnant women with AS secreted only small amounts of interleukin-10 and showed lower suppression of tumor necrosis factor alpha and interferon-gamma secretion by CD4+CD25- Teff cells. At the postpartum time point, proinflammatory cytokine levels in the Treg/Teff cell cocultures and Teff cell monocultures were significantly higher in patients with AS than in healthy controls. CONCLUSION: Pregnancy influenced the expansion and cytokine secretion of Treg cells in both patients with AS and control subjects. However, the Treg cells of pregnant patients with AS failed to support an antiinflammatory cytokine milieu, thereby possibly contributing to the persistent disease activity of AS during pregnancy.

Endothelial cell activation leads to neutrophil transmigration as supported by the sequential roles of ICAM-2, JAM-A, and PECAM-1

Leukocyte transmigration is mediated by endothelial cell (EC) junctional molecules, but the associated mechanisms remain unclear. Here we investigate how intercellular adhesion molecule-2 (ICAM-2), junctional adhesion molecule-A (JAM-A), and platelet endothelial cell adhesion molecule (PECAM-1) mediate neutrophil transmigration in a stimulus-dependent manner (eg, as induced by interleukin-1beta [IL-1beta] but not tumor necrosis factor-alpha [TNF-alpha]), and demonstrate their ability to act in sequence. Using a cell-transfer technique, transmigration responses of wild-type and TNF-alpha p55/p75 receptor-deficient leukocytes (TNFR(-/-)) through mouse cremasteric venules were quantified by fluorescence intravital microscopy. Whereas wild-type leukocytes showed a normal transmigration response to TNF-alpha in ICAM-2(-/-), JAM-A(-/-), and PECAM-1(-/-) recipient mice, TNFR(-/-) leukocytes exhibited a reduced transmigration response. Hence, when the ability of TNF-alpha to directly stimulate neutrophils is blocked, TNF-alpha-induced neutrophil transmigration is rendered dependent on ICAM-2, JAM-A, and PECAM-1, suggesting that the stimulus-dependent role of these molecules is governed by the target cell being activated. Furthermore, analysis of the site of arrest of neutrophils in inflamed tissues from ICAM-2(-/-), JAM-A(-/-), and PECAM-1(-/-) mice demonstrated that these molecules act sequentially to mediate transmigration. Collectively, the findings provide novel insights into the mechanisms of action of key molecules implicated in leukocyte transmigration.

Expression and regulation of antimicrobial peptide rCRAMP after bacterial infection in primary rat meningeal cells

Bacterial meningitis is characterized by an inflammation of the meninges and continues to be an important cause of mortality and morbidity. Meningeal cells cover the cerebral surface and are involved in the first interaction between pathogens and the brain. Little is known about the role of meningeal cells and the expression of antimicrobial peptides in the innate immune system. In this study we characterized the expression, secretion and bactericidal properties of rat cathelin-related antimicrobial peptide (rCRAMP), a homologue of the human LL-37, in rat meningeal cells after incubation with different bacterial supernatants and the bacterial cell wall components lipopolysaccharide (LPS) and peptidoglycan (PGN). Using an agar diffusion test, we observed that supernatants from meningeal cells incubated with bacterial supernatants, LPS and PGN showed signs of antimicrobial activity. The inhibition of rCRAMP expression using siRNA reduced the antimicrobial activity of the cell culture supernatants. The expression of rCRAMP in rat meningeal cells involved various signal transduction pathways and was induced by the inflammatory cytokines interleukin-1, -6 and tumor necrosis factor alpha. In an experimental model of meningitis, infant rats were intracisternally infected with Streptococcus pneumoniae and rCRAMP was localized in meningeal cells using immunohistochemistry. These results suggest that cathelicidins produced by meningeal cells play an important part in the innate immune response against pathogens in CNS bacterial infections.

Relationship between inflammation and cognitive function in obstructive sleep apnea

OBJECTIVES: Obstructive sleep apnea (OSA) can have adverse effects on cognitive functioning, mood, and cardiovascular functioning. OSA brings with it disturbances in sleep architecture, oxygenation, sympathetic nervous system function, and inflammatory processes. It is not clear which of these mechanisms is linked to the decrease in cognitive functioning. This study examined the effect of inflammatory parameters on cognitive dysfunction. MATERIALS AND METHODS: Thirty-nine patients with untreated sleep apnea were evaluated by polysomnography and completed a battery of neuropsychological tests. After the first night of evaluation in the sleep laboratory, blood samples were taken for analysis of interleukin 6, tumor necrosis factor-alpha (TNF-alpha), and soluble TNF receptor 1 (sTNF-R1). RESULTS: sTNF-R1 significantly correlated with cognitive dysfunction. In hierarchical linear regression analysis, measures of obstructive sleep apnea severity explained 5.5% of the variance in cognitive dysfunction (n.s.). After including sTNF-R1, percentage of variance explained by the full model increased more than threefold to 19.6% (F = 2.84, df = 3, 36, p = 0.05). Only sTNF-R1 had a significant individual relationship with cognitive dysfunction (beta = 0.376 t = 2.48, p = 0.02). CONCLUSIONS: sTNF-R1 as a marker of chronic inflammation may be associated with diminished neuropsychological functioning in patients with OSA.

Analysis of key molecules of the innate immune system in mammary epithelial cells isolated from marker-assisted and conventionally selected cattle

Mastitis is the most prevalent infectious disease in dairy herds. Breeding programs considering mastitis susceptibility were adopted as approaches to improve udder health status. In recent decades, conventional selection criteria based on phenotypic characteristics such as somatic cell score in milk have been widely used to select animals. Recently, approaches to incorporate molecular information have become feasible because of the detection of quantitative trait loci (QTL) affecting mastitis resistance. The aims of the study were to explore molecular mechanisms underlying mastitis resistance and the genetic mechanisms underlying a QTL on Bos taurus chromosome 18 found to influence udder health. Primary cell cultures of mammary epithelial cells from heifers that were selected for high or low susceptibility to mastitis were established. Selection based on estimated pedigree breeding value or on the basis of marker-assisted selection using QTL information was implemented. The mRNA expression of 10 key molecules of the innate immune system was measured using quantitative real-time PCR after 1, 6, and 24 h of challenge with heat-inactivated mastitis pathogens (Escherichia coli and Staphylococcus aureus) and expression levels in the high and low susceptibility groups were compared according to selection criteria. In the marker-assisted selection groups, mRNA expression in cells isolated from less-susceptible animals was significantly elevated for toll-like receptor 2, tumor necrosis factor-alpha, IL-1beta, IL-6, IL-8, RANTES (regulated upon activation, normal t-cell expressed and secreted), complement factor C3, and lactoferrin. In the estimated pedigree breeding value groups, mRNA expression was significantly elevated only for V-rel reticuloendotheliosis viral oncogene homolog A, IL-1 beta, and RANTES. These observations provide first insights into genetically determined divergent reactions to pathogens in the bovine mammary gland and indicate that the application of QTL information could be a successful tool for the selection of animals resistant to mastitis.

The potential association between gingival crevicular fluid inflammatory mediators and adverse pregnancy outcomes: a systematic review

OBJECTIVES The association between periodontal disease and adverse pregnancy outcomes (APO), primarily preterm birth (PTB), is still controversially discussed in the literature. Therefore, the aim of the present systematic review was to analyze the existing literature on the potential association between inflammatory mediators detected in gingival crevicular fluid (GCF) and APO. MATERIALS AND METHODS MEDLINE (PubMed) and EMBASE databases were searched for entries up to April 2012 and studies were selected by two independent reviewers. RESULTS The majority of the eight studies included confirmed a positive association between GCF mediators, such as interleukin-1β, prostaglandin E2, and tumor necrosis factor-alpha, and APO. Due to the heterogeneity and variability of the available studies, no meta-analysis could be performed. CONCLUSIONS A positive association between GCF inflammatory mediator levels and APO/PTB might be present but the results need to be considered with great caution because of the heterogeneity and variability among the studies. Further studies with an adequate number of patients allowing for an appropriate analysis are warranted to definitely confirm this association. CLINICAL RELEVANCE The present findings suggest that an association between GCF inflammatory mediator levels and APO might exist.

Vascular cell adhesion molecule 1 expression by biliary epithelium promotes persistence of inflammation by inhibiting effector T-cell apoptosis

Chronic hepatitis occurs when effector lymphocytes are recruited to the liver from blood and retained in tissue to interact with target cells, such as hepatocytes or bile ducts (BDs). Vascular cell adhesion molecule 1 (VCAM-1; CD106), a member of the immunoglobulin superfamily, supports leukocyte adhesion by binding a4b1 integrins and is critical for the recruitment of monocytes and lymphocytes during inflammation. We detected VCAM-1 on cholangiocytes in chronic liver disease (CLD) and hypothesized that biliary expression of VCAM-1 contributes to the persistence of liver inflammation. Hence, in this study, we examined whether cholangiocyte expression of VCAM-1 promotes the survival of intrahepatic a4b1 expressing effector T cells. We examined interactions between primary human cholangiocytes and isolated intrahepatic T cells ex vivo and in vivo using the Ova-bil antigen-driven murine model of biliary inflammation. VCAM-1 was detected on BDs in CLDs (primary biliary cirrhosis, primary sclerosing cholangitis, alcoholic liver disease, and chronic hepatitis C), and human cholangiocytes expressed VCAM-1 in response to tumor necrosis factor alpha alone or in combination with CD40L or interleukin-17. Liver-derived T cells adhered to cholangiocytes in vitro by a4b1, which resulted in signaling through nuclear factor kappa B p65, protein kinase B1, and p38 mitogen-activated protein kinase phosphorylation. This led to increased mitochondrial B-cell lymphoma 2 accumulation and decreased activation of caspase 3, causing increased cell survival. We confirmed our findings in a murine model of hepatobiliary inflammation where inhibition of VCAM-1 decreased liver inflammation by reducing lymphocyte recruitment and increasing CD8 and T helper 17 CD4 Tcell survival. Conclusions: VCAM-1 expression by cholangiocytes contributes to persistent inflammation by conferring a survival signal to a4b1 expressing proinflammatory T lymphocytes in CLD.

Intracisternal application of endotoxin enhances the susceptibility to subsequent hypoxic-ischemic brain damage in neonatal rats.

Perinatal brain damage is associated not only with hypoxic-ischemic insults but also with intrauterine inflammation. A combination of antenatal inflammation and asphyxia increases the risk of cerebral palsy >70 times. The aim of the present study was to determine the effect of intracisternal (i.c.) administration of endotoxin [lipopolysaccharides (LPS)] on subsequent hypoxic-ischemic brain damage in neonatal rats. Seven-day-old Wistar rats were subjected to i.c. application of NaCl or LPS (5 microg/pup). One hour later, the left common carotid artery was exposed through a midline neck incision and ligated with 6-0 surgical silk. After another hour of recovery, the pups were subjected to a hypoxic gas mixture (8% oxygen/92% nitrogen) for 60 min. The animals were randomized to four experimental groups: 1) sham control group, left common carotid artery exposed but not ligated (n = 5); 2) LPS group, subjected to i.c. application of LPS (n = 7); 3) hypoxic-ischemic study group, i.c. injection of NaCl and exposure to hypoxia after ligation of the left carotid artery (n = 17); or 4) hypoxic-ischemic/LPS study group, i.c. injection of LPS and exposure to hypoxia after ligation of the left carotid artery (n = 19). Seven days later, neonatal brains were assessed for neuronal cell damage. In a second set of experiments, rat pups received an i.c. injection of LPS (5 microg/pup) and were evaluated for tumor necrosis factor-alpha expression by immunohistochemistry. Neuronal cell damage could not be observed in the sham control or in the LPS group. In the hypoxic-ischemic/LPS group, neuronal injury in the cerebral cortex was significantly higher than in animals that were subjected to hypoxia/ischemia after i.c. application of NaCl. Injecting LPS intracisternally caused a marked expression of tumor necrosis factor-alpha in the leptomeninges. Applying LPS intracisternally sensitizes the immature rat brain to a subsequent hypoxic-ischemic insult.