Cyclosporine A enhances leukocyte binding by human intestinal microvascular endothelial cells through inhibition of p38 MAPK and iNOS. Paradoxical proinflammatory effect on the microvascular endothelium

Mafosfamide, a cyclophosphamide analog, causes a proinflammatory response and increased permeability on endothelial cells in vitro

Post-transplantation cyclophosphamide (PTCy) has decreased GVHD incidence. Endothelial damage in allo-HCT is caused by multiple factors, including conditioning treatments and some immunosupressants, and underlies HCT-complications as GVHD. Nevertheless, the specific impact of PTCy on the endothelium remains unclear. We evaluated the effect of mafosfamide (MAF), an active Cy analog, on endothelial cells (ECs) vs. cyclosporine A (CSA), with known damaging endothelial effect. ECs were exposed to MAF and CSA to explore changes in endothelial damage markers: (i) surface VCAM-1, (ii) leukocyte adhesion on ECs, (iii) VE-cadherin expression, (iv) production of VWF, and (v) activation of intracellular signaling proteins (p38MAPK, Akt). Results obtained (expressed in folds vs. controls) indicate that both compounds increased VCAM-1 expression (3.1 ± 0.3 and 2.8 ± 0.6, respectively, p < 0.01), with higher leukocyte adhesion (5.5 ± 0.6, p < 0.05, and 2.8 ± 0.4, respectively). VE-cadherin decreased with MAF (0.8 ± 0.1, p < 0.01), whereas no effect was observed with CSA. Production of VWF augmented with CSA (1.4 ± 0.1, p < 0.01), but diminished with MAF (0.9 ± 0.1, p < 0.05). p38MAPK activation occurred with both compounds, being more intense and faster with CSA. Both drugs activated Akt, with superior MAF effect at longer exposure. Therefore, the cyclophosphamide analog MAF is not exempt from a proinflammatory effect on the endothelium, though without modifying the subendothelial characteristics.

Effect of Fosfomycin on Cyclosporine Nephrotoxicity

Fosfomycin (Fos) has emerged as a potential treatment against multidrug-resistant organisms, however, there has been little work done on its influence on calcineurin inhibitor nephrotoxicity (CIN). This study was designed to evaluate the effect of Fos in combination with cyclosporine (CsA) on CIN. Two sets of experiments were undertaken. In the first, Wistar rats received different doses of Fos: 0, 62.5, 125, 250, and 500 mg/kg. In the second, rats were divided into four groups: control, CsA 15 mg/kg s.c., CsA + fosfomycin 62.5 mg/kg (CsA + LF), and CsA + Fos 500 mg/kg (CsA + HF). CsA was administrated daily for 14 days, whereas Fos administration started on the ninth day followed by two more doses, delivered 48 h apart. The administration of different Fos doses did not alter renal function. In contrast, CsA induced arteriolopathy, hypoperfusion, a reduction in the glomerular filtration rate, and downregulation of eNOS, angiotensinogen, and AT1R mRNA levels. Lower doses of Fos did not modify CIN. Instead, the CsA + HF group exhibited greater hypoperfusion, arteriolopathy, and oxidative stress, and increased mRNA levels of pro-inflammatory cytokines. This study shows that Fos administered by itself at different doses did not cause renal injury, but when it was given repeatedly at high dosages (500 mg/kg) in combination with CsA, it increased CIN through the promotion of greater oxidative stress and renal inflammation.

Experimental and Clinical Evidence of Endothelial Dysfunction in Inflammatory Bowel Disease

The endothelium has a crucial role in proper hemodynamics. Inflammatory bowel disease (IBD) is mainly a chronic inflammatory condition of the gastrointestinal tract. However, considerable evidence points to high cardiovascular risk in patients with IBD. This review positions the basic mechanisms of endothelial dysfunction in the IBD setting (both clinical and experimental). Furthermore, we review the main effects of drugs used to treat IBD in endothelial (dys)function. Moreover, we leave challenging points for enlarging the therapeutic arsenal for IBD with new or repurposed drugs that target endothelial dysfunction besides inflammation.

Bioinformatics-based study to detect chemical compounds that show potential as treatments for pulmonary thromboembolism

The objectives of the present study comprised the recognition of major genes related to pulmonary thromboembolism (PTE) and the evaluation of their functional enrichment levels, in addition to the identification of small chemical molecules that may offer potential for use in PTE treatment. The RNA expression profiling of GSE84738 was obtained from the Gene Expression Omnibus database. Following data preprocessing, the differently expressed genes (DEGs) between the PTE group and the control group were identified using the Linear Models for Microarray package. Subsequently, the protein‑protein interaction (PPI) network of these DEGs was examined using the Search Tool for the Retrieval of Interacting Genes/Proteins database, visualized via Cytoscape. The most significantly clustered modules in the network were identified using Multi Contrast Delayed Enhancement, a plugin of Cytoscape. Subsequently, functional enrichment analysis of the DEGs was performed, using the Database for Annotation Visualization and Integrated Discovery tool. Furthermore, the chemical‑target interaction networks were investigated using the Comparative Toxicogenomics Database as visualized via Cytoscape. A total of 548 DEGs (262 upregulated and 286 downregulated) were identified in the PTE group, compared with the control group. The upregulated and downregulated genes were enriched in Gene Ontology terms related to inflammation and eye sarcolemma, respectively. Tumor necrosis factor (TNF) and erb‑b2 receptor tyrosine kinase 2 (ERBB2) were upregulated genes that ranked higher in the PPI network (47 and 40 degrees, respectively) whereas C‑JUN was the most downregulated gene (46). Small chemical molecules ethinyl (135), cyclosporine (126), thrombomodulin precursor (113) and tretinoin (111) had >100 degrees in the DEG‑chemical interaction network. In addition, ethinyl targeted to TNF, whereas TNF and ERBB2 were targeted by cyclosporine, and tretinoin was a targeted chemical of ERBB2. Therefore, cyclosporine, ethinyl, and tretinoin may be potential targets for PTE treatment.

Curcumin, Cardiometabolic Health and Dementia

Current research indicates curcumin [diferuloylmethane; a polyphenolic compound isolated from the rhizomes of the dietary spice turmeric (Curcuma longa)] exerts a beneficial effect on health which may be partly attributable to its anti-oxidative and anti-inflammatory properties. The aim of this review is to examine potential mechanisms of the actions of curcumin in both animal and human studies. Curcumin modulates relevant molecular target pathways to improve glucose and lipid metabolism, suppress inflammation, stimulate antioxidant enzymes, facilitate insulin signalling and reduce gut permeability. Curcumin also inhibits Aβ and tau accumulation in animal models and enhances mitochondria and synaptic function. In conclusion, in high-dose animal studies and in vitro, curcumin exerts a potential beneficial effect on cardiometabolic disease. However, human studies are relatively unconvincing. More intervention studies should be conducted with the new curcumin formulation with improved oral bioavailability.

Calcineurin inhibitors exacerbate coronary arteritis via the MyD88 signalling pathway in a murine model of Kawasaki disease

Calcineurin inhibitors (CNIs) have been used off-label for the treatment of refractory Kawasaki disease (KD). However, it remains unknown whether CNIs show protective effects against the development of coronary artery lesions in KD patients. To investigate the effects of CNIs on coronary arteries and the mechanisms of their actions on coronary arteritis in a mouse model of KD, we performed experiments with FK565, a ligand of nucleotide-binding oligomerization domain-containing protein 1 (NOD1) in wild-type, severe combined immunodeficiency (SCID), caspase-associated recruitment domain 9 (CARD9)^-/- and myeloid differentiation primary response gene 88 (MyD88)^-/- mice. We also performed in-vitro studies with vascular and monocytic cells and vascular tissues. A histopathological analysis showed that both cyclosporin A and tacrolimus exacerbated the NOD1-mediated coronary arteritis in a dose-dependent manner. Cyclosporin A induced the exacerbation of coronary arteritis in mice only in high doses, while tacrolimus exacerbated it within the therapeutic range in humans. Similar effects were obtained in SCID and CARD9^-/- mice but not in MyD88^-/- mice. CNIs enhanced the expression of adhesion molecules by endothelial cells and the cytokine secretion by monocytic cells in our KD model. These data indicated that both vascular and monocytic cells were involved in the exacerbation of coronary arteritis. Activation of MyD88-dependent inflammatory signals in both vascular cells and macrophages appears to contribute to their adverse effects. Particular attention should be paid to the development of coronary artery lesions when using CNIs to treat refractory KD.

Transplant-associated thrombotic microangiopathy: opening Pandora's box

Transplant-associated thrombotic microangiopathy (TA-TMA) is an early complication of hematopoietic cell transplantation (HCT). A high mortality rate is documented in patients who are refractory to calcineurin inhibitor cessation. Estimates of TA-TMA prevalence vary significantly and are higher in allogeneic compared with autologous HCT. Furthermore, our understanding of the pathophysiology that is strongly related to diagnosis and treatment options is limited. Recent evidence has linked TA-TMA with atypical hemolytic uremic syndrome, a disease of excessive activation of the alternative pathway of complement, opening the Pandora's box in treatment options. As conventional treatment management is highly inefficient, detection of complement activation may allow for early recognition of patients who will benefit from complement inhibition. Preliminary clinical results showing successful eculizumab administration in children and adults with TA-TMA need to be carefully evaluated. Therefore, realizing the unmet needs of better understanding TA-TMA in this complex setting, we aimed to summarize current knowledge focusing on (1) critical evaluation of diagnostic criteria, (2) epidemiology and prognosis, (3) recent evidence of complement activation and endothelial damage and (4) treatment options.

2-Hydroxyeupatolide attenuates inflammatory responses via the inhibiting of NF-κB signaling pathways

2-Hydroxyeupatolide (2-HE), a sesquiterpene lactone, is a potential agent to improve LPS-induced acute mouse inflammation damage.

Calcineurin inhibitors cyclosporine A and tacrolimus induce vascular inflammation and endothelial activation through TLR4 signaling

The introduction of the calcineurin inhibitors (CNIs) cyclosporine and tacrolimus greatly reduced the rate of allograft rejection, although their chronic use is marred by a range of side effects, among them vascular toxicity. In transplant patients, it is proved that innate immunity promotes vascular injury triggered by ischemia-reperfusion damage, atherosclerosis and hypertension. We hypothesized that activation of the innate immunity and inflammation may contribute to CNI toxicity, therefore we investigated whether TLR4 mediates toxic responses of CNIs in the vasculature. Cyclosporine and tacrolimus increased the production of proinflammatory cytokines and endothelial activation markers in cultured murine endothelial and vascular smooth muscle cells as well as in ex vivo cultures of murine aortas. CNI-induced proinflammatory events were prevented by pharmacological inhibition of TLR4. Moreover, CNIs were unable to induce inflammation and endothelial activation in aortas from TLR4^−/− mice. CNI-induced cytokine and adhesion molecules synthesis in endothelial cells occurred even in the absence of calcineurin, although its expression was required for maximal effect through upregulation of TLR4 signaling. CNI-induced TLR4 activity increased O₂⁻/ROS production and NF-κB-regulated synthesis of proinflammatory factors in cultured as well as aortic endothelial and VSMCs. These data provide new insight into the mechanisms associated with CNI vascular inflammation.

Dysregulation of WNT5A/ROR2 Signaling Characterizes the Progression of Barrett-Associated Esophageal Adenocarcinoma

The mechanism underlying the progression of normal esophageal mucosa to esophageal adenocarcinoma remains elusive. WNT5A is a noncanonical WNT, which mainly functions via the receptor tyrosine kinase-like orphan receptor 2 (ROR2), and has an unclear role in carcinogenesis. In this study, we aimed to determine the role of WNT5A/ROR2 signaling in esophageal adenocarcinoma. Analysis of WNT5A and ROR2 expression patterns in healthy controls, Barrett and esophageal adenocarcinoma patients' esophageal clinical specimens as well as in various esophageal cell lines demonstrated a ROR2 overexpression in esophageal adenocarcinoma tissues compared with Barrett and healthy mucosa, whereas WNT5A expression was found significantly downregulated toward esophageal adenocarcinoma formation. Treatment of esophageal adenocarcinoma OE33 cells with human recombinant WNT5A (rhWNT5A) significantly suppressed proliferation, survival, and migration in a dose-dependent fashion. rhWNT5A was found to inhibit TOPflash activity in ROR2 wild-type cells, whereas increased TOPflash activity in ROR2-knockdown OE33 cells. In addition, ROR2 knockdown alone abolished cell proliferation and weakened the migration properties of OE33 cells. These findings support an early dysregulation of the noncanonical WNT5A/ROR2 pathway in the pathogenesis of esophageal adenocarcinoma, with the loss of WNT5A expression together with the ROR2 overexpression to be consistent with tumor promotion.

IMPLICATIONS

The dysregulation of WNT5A/ROR2 noncanonical WNT signaling in Barrett-associated esophageal adenocarcinoma introduces possible prognostic markers and novel targets for tailored therapy of this malignancy. Mol Cancer Res; 14(7); 647-59. ©2016 AACR.

Update on pathogenesis and predictors of response of therapeutic strategies used in inflammatory bowel disease

The search for biomarkers that characterize specific aspects of inflammatory bowel disease (IBD), has received substantial interest in the past years and is moving forward rapidly with the help of modern technologies. Nevertheless, there is a direct demand to identify adequate biomarkers for predicting and evaluating therapeutic response to different therapies. In this subset, pharmacogenetics deserves more attention as part of the endeavor to provide personalized medicine. The ultimate goal in this area is the adjustment of medication for a patient’s specific genetic background and thereby to improve drug efficacy and safety rates. The aim of the following review is to utilize the latest knowledge on immunopathogenesis of IBD and update the findings on the field of Immunology and Genetics, to evaluate the response to the different therapies. In the present article, more than 400 publications were reviewed but finally 287 included based on design, reproducibility (or expectancy to be reproducible and translationable into humans) or already measured in humans. A few tests have shown clinical applicability. Other, i.e., genetic associations for the different therapies in IBD have not yet shown consistent or robust results. In the close future it is anticipated that this, cellular and genetic material, as well as the determination of biomarkers will be implemented in an integrated molecular diagnostic and prognostic approach to manage IBD patients.

Venous thrombosis and prothrombotic factors in inflammatory bowel disease

Patients with inflammatory bowel disease (IBD) may have an increased risk of venous thrombosis (VTE). PubMed, ISI Web of Knowledge and Scopus were searched to identify studies investigating the risk of VTE and the prevalence of acquired and genetic VTE risk factors and prothrombotic abnormalities in IBD. Overall, IBD patients have a two- to fourfold increased risk of VTE compared with healthy controls, with an overall incidence rate of 1%-8%. The majority of studies did not show significant differences in the risk of VTE between Crohn’s disease and ulcerative colitis. Several acquired factors are responsible for the increased risk of VTE in IBD: inflammatory activity, hospitalisation, surgery, pregnancy, disease phenotype (e.g., fistulising disease, colonic involvement and extensive involvement) and drug therapy (mainly steroids). There is also convincing evidence from basic science and from clinical and epidemiological studies that IBD is associated with several prothrombotic abnormalities, including initiation of the coagulation system, downregulation of natural anticoagulant mechanisms, impairment of fibrinolysis, increased platelet count and reactivity and dysfunction of the endothelium. Classical genetic alterations are not generally found more often in IBD patients than in non-IBD patients, suggesting that genetics does not explain the greater risk of VTE in these patients. IBD VTE may have clinical specificities, namely an earlier first episode of VTE in life, high recurrence rate, decreased efficacy of some drugs in preventing further episodes and poor prognosis. Clinicians should be aware of these risks, and adequate prophylactic actions should be taken in patients who have disease activity, are hospitalised, are submitted to surgery or are undergoing treatment.

Distinct deleterious effects of cyclosporine and tacrolimus and combined tacrolimus-sirolimus on endothelial cells: protective effect of defibrotide

Endothelial dysfunction seems to be a key factor in the development of several complications observed early after hematopoietic stem cell transplantation (HSCT). The conditioning regimen and many other factors associated with the procedure are responsible for this endothelial damage. The effects of immunosuppressive agents on endothelial function have not been explored in detail. We evaluated the effects of 3 drugs commonly used in HSCT: 2 calcineurin inhibitors, cyclosporine A (CSA) and tacrolimus (TAC), and an inhibitor of mTOR, sirolimus (SIR). We also evaluated the effect of the combination of TAC and SIR (TAC+SIR), which is used increasingly in clinical practice. Microvascular endothelial cells (HMEC-1) were exposed to these drugs to evaluate changes in (1) intercellular adhesion molecule (ICAM)-1 expression on the cell surface, assessed by immunofluorescence labeling and expressed as the mean gray value (MGV); (2) reactivity of the extracellular matrix (ECM) toward platelets, upon exposure of the ECM to circulating blood; and (3) whole-blood clot formation, assessed by thromboelastometry. Studies were conducted in the absence and presence of defibrotide (DF) to assess its possible protective effect. The exposure of HMEC-1 to CSA and TAC+SIR significantly increased the expression of ICAM-1 (157.5 ± 11.6 and 153.4 ± 9.5 MGV, respectively, versus 105.7 ± 6.5 MGV in controls [both P < .05]). TAC applied alone increased ICAM-1 slightly (120.3 ± 8.2 MGV), and SIR had no effect (108.9 ± 7.4 MGV). ECM reactivity increased significantly only in response to CSA (surface covered by platelets of 41.2% ± 5.4% versus 30.1% ± 2.0%, P < .05). DF attenuated all these changes. No significant changes in the viscoelastic properties of clot formation were observed in any condition with blood samples incubated in vitro. In conclusion, CSA and TAC+SIR had a proinflammatory effect, but only CSA exhibited an additional prothrombotic effect. Interestingly, DF exerted clear protective anti-inflammatory and antithrombotic effects on the endothelium.

Anti-inflammatory effect of essential oil and its constituents from fingered citron (Citrus medica L. var. sarcodactylis) through blocking JNK, ERK and NF-κB signaling pathways in LPS-activated RAW 264.7 cells

We investigated the composition of essential oil from fingered citron (Citrus medica L. var. sarcodactylis) (FCEO) peels by GC-MS and its anti-inflammatory effects on lipopolysaccharide (LPS) - stimulated mouse macrophage (RAW 264.7) cells. Fifteen compounds, representing 98.97% of the essential oil, were tentatively identified; the main constituents were limonene (52.44%) and γ-terpinene (28.41%). FCEO significantly inhibited nitric oxide (NO) and prostaglandin E2 (PGE2) by suppressing the protein expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2, respectively. Additionally, FCEO suppressed the production of tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, and IL-6. FCEO attenuated LPS-induced nuclear factor-κB (NF-κB) activation via inhibition of inhibitor κB-α phosphorylation. Furthermore, FCEO blocked activation of c-Jun N-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK) but not that of p38 mitogen-activated protein kinase. These results indicate that FCEO inhibits LPS-stimulated inflammation by blocking the NF-κB, JNK, and ERK pathways in macrophages, and demonstrate that FCEO possesses anti-inflammatory properties.

Efficacy of drugs used in the treatment of IBD and combinations thereof in acute DSS-induced colitis in mice

AIMS

Although acute dextran sodium sulphate (DSS)-induced colitis in mice is frequently used as a preclinical model for testing drugs involved in inflammatory bowel disease (IBD), only limited data is available that compares the efficacy of established drug treatments and combinations employed in IBD. We have therefore compared the efficacy of aminosalicylates (mesalazine, olsalazine), corticosteroids (budesonide), thiopurines (6-thioguanine (6-TG)) and cyclosporine A (CsA) and combinations thereof as well as the EP4 agonist AGN205203 in the acute DSS-colitis model.

MAIN METHODS

Female BALB/c mice were challenged with 4% DSS in drinking water for 7 days to induce colitis and treated daily with different drugs/combinations orally. Disease scores (diarrhoea, bleeding, disease activity index), systemic (body weight loss, serum amyloid A levels) and colonic (myeloperoxidase activity, length and histopathology) inflammation parameters were analysed.

KEY FINDINGS

Mesalazine, olsalazine (100mg/kg) and budesonide (0.5mg/kg) were only weakly active or even worsened colitis. 6-TG dose-dependently reduced systemic and colonic inflammation parameters with estimated ED50 values between 0.5-4 mg/kg. CsA (10, 25 and 50mg/kg) dose-dependently reduced colitis with high efficacy on systemic inflammation. A combination of CsA 25mg/kg+olsalazine 100mg/kg produced a more pronounced anti-inflammatory effect than the compounds given alone. AGN205203 (3, 10 and 30 mg/kg BID) was the most efficacious compound and almost completely inhibited colitis.

SIGNIFICANCE

6-TG and CsA are suitable reference compounds in the DSS mouse model. CsA+olsalazine, as a combination, was more efficacious than the compounds given alone, supporting combination treatments in IBD.

EUK-207 protects human intestinal microvascular endothelial cells (HIMEC) against irradiation-induced apoptosis through the Bcl2 pathway

AIM

To elucidate the signaling mechanisms involved in the protective effect of EUK-207 against irradiation-induced cellular damage and apoptosis in human intestinal microvasculature endothelial cells (HIMEC).

METHODS

HIMECs were irradiated and treated with EUK-207. Using hydroethidine and DCF-DA fluorescent probe the intracellular superoxide and reactive oxygen species (ROS) were determined. By real-time PCR and western blotting caspase-3, Bcl2 and Bax genes and proteins were analyzed. Proliferation was determined by [(3)H]-thymidine uptake. Immunofluorescence staining was used for translocation of p65 NFκB subunit.

KEY FINDING

Irradiation increased ROS production, apoptosis, Bax, Caspase3 and NFkB activity in HIMEC and inhibited cell survival/growth/proliferation. EUK-207 restored the endothelial functions, markedly inhibited the ROS, up-regulated the Bcl2 and down-regulated Bax and prevented NFκB caspase 3 activity in HIMEC.

SIGNIFICANCE

HIMEC provide a novel model to define the effect of irradiation induced endothelial dysfunction. Our findings suggest that EUK-207 effectively inhibits the damaging effect of irradiation.

Anti-inflammatory effects of Amomum compactum on RAW 264.7 cells via induction of heme oxygenase-1

Amomum compactum is commonly used in Korean traditional medicine. In this study, we demonstrate that A. compactum ethanolic extract (ACEE) has anti-inflammatory effects in a lipopolysaccharide-induced RAW 264.7 cell model of inflammation. In this system, ACEE prominently inhibited the production of nitric oxide (NO), prostaglandin E(2) (PGE(2)), interleukin (IL)-6 and tumor necrosis factor (TNF)-α, and inhibited the protein expression of inducible nitric oxide synthase and cyclooxygenase-2. Furthermore, ACEE treatment inhibited the translocation of nuclear factor-kappaB (NF-κB) and the degradation of inhibitory factor-kappaB alpha, but enhanced the expression of heme oxygenase (HO)-1 and the nuclear translocation of nuclear factor-erythroid 2 (Nrf2). Treatment with tin protoporphyrin IX dichloride (SnPP), a selective HO-1 inhibitor, reversed the ACEE-induced suppression of NO production, suggesting that the induction of HO-1 is involved in the suppression of NO, TNF-α, and IL-6 production by ACEE. Taken together, these results suggest that ACEE have anti-inflammatory effects occurring through HO-1 induction, which leads to suppression of the blocking NF-κB.

Inhibitory effect of ginsenoside-Rd on carrageenan-induced inflammation in rats

A previous study reported that ginsenoside-Rd reduced the production of tumor necrosis factor-α by inhibiting nuclear factor-κB in lipopolysaccharide-activated N9 microglia in vitro. The aim of the present study was to confirm the anti-inflammatory effects and mechanisms of ginsenoside-Rd in animal experiments involving acute inflammation. The results indicated that ginsenoside-Rd at doses ranging from 12.5 to 50 mg/kg i.m. significantly inhibited the swelling of hind paws in rats for 1-6 h after the carrageenan injection. The levels of proinflammatory cytokines and proinflammatory mediators were markedly reduced by ginsenoside-Rd. Ginsenoside-Rd, when administered intramuscularly at 12.5, 25, and 50 mg/kg doses, showed signicant inhibition of carrageenan-induced production of interleukin-1β (6.91%, 45.75%, and 55.18%, respectively), tumor necrosis factor-α (37.99%, 56.39%, and 47.38%, respectively), prostaglandin E(2) (22.92%, 30.12%, and 36.36%, respectively), and nitric oxide (28.27%, 44.53%, and 53.42%, respectively). In addition, ginsenoside-Rd (12.5, 25, and 50 mg/kg i.m.) effectively decreased the levels of nuclear factor-κB (6.77%, 20.28%, and 41.03%, respectively) and phosphorylation of IκBα (13.23%, 26.92%, and 41.80%, respectively) in the carrageenan-inflamed paw tissues. These results suggest that ginsenoside-Rd has significant anti-inflammatory effects in vivo, which might be due to its blocking of the nuclear factor-κB signaling pathway. Thus, it may be possible to develop ginsenoside-Rd as a useful agent for inflammatory diseases.

Epidermal Growth Factor–Like Domain 7 Is a Novel Inhibitor of Neutrophil Adhesion to Coronary Artery Endothelial Cells Injured by Calcineurin Inhibition

Background—

We investigated the effect of epidermal growth factor–like domain 7 (Egfl7) on nuclear factor-κB activation, intercellular adhesion molecule-1 expression, and neutrophil adhesion to human coronary artery endothelial cells after calcineurin-inhibition–induced injury.

Methods and Results—

Human coronary endothelial cells were incubated with cyclosporine (CyA) 10 μg/mL with or without Egfl7 (100 ng/mL) or the Notch receptor activator Jagged1 (200 ng/mL) for 6 to 48 hours. CyA upregulated nuclear factor-κB (p65) activity (128±2% of control, P <0.001) in nuclear extracts, as determined with a DNA-binding activity ELISA. This activity was inhibited by Egfl7 (86±3% of control; P <0.001 versus CyA alone). Jagged1 blocked Egfl7-induced nuclear factor-κB inhibition (105±4% of control; P <0.05 versus CyA plus Egfl7). CyA upregulated cell-surface intercellular adhesion molecule-1 expression (215±13% of control; P <0.001), as determined by flow cytometry. This expression was suppressed by Egfl7 (148±5%; P <0.001 versus CyA alone). Jagged1 attenuated the intercellular adhesion molecule-1–suppressive effect of Egfl7 when administered with CyA (193±3% versus 148±5%; P <0.01). CyA increased neutrophil adhesion to human coronary endothelial cells (control 20±5%, CyA 37±3%; P <0.001 versus control) in a nonstatic neutrophil adhesion assay. This increase was attenuated by Egfl7 (22±6%; P <0.001 versus CyA alone). Jagged 1 attenuated the effect of Egfl7 on neutrophil adhesion (31±3%; P <0.001 versus Egfl7 plus CyA).

Conclusions—

Our study reveals that Egfl7 is a potent inhibitor of neutrophil adhesion to human coronary endothelial cells subsequent to calcineurin-inhibition–induced injury. Mechanistically, Egfl7 blocked nuclear factor-κB pathway activation and intercellular adhesion molecule-1 expression, which suggests that it may have significant antiinflammatory properties. Because Jagged1 blocked the effect of Egfl7, Notch receptor antagonism may contribute to the mechanism of action of Egfl7.

Microvascular endothelial cells play potential immunoregulatory roles in the immune response to foot-and-mouth disease vaccines

Microvascular endothelial cells (MVECs) have been documented to have important immunoregulatory effects. Exploring their roles in the immune response to foot-and-mouth disease (FMD) vaccines would help to improve their efficacy. In this study, the effects of FMD vaccine 146s antigens on gene expression profiles of rat intestinal mucosal and myocardial MVECs were analysed using microarray, and their effects on transendothelial migration (TEM) of peripheral blood mononuclear cells (PBMC) were investigated by the Transwell migration assay. Both kinds of MVECs displayed significant responses to 146s antigens, and 252 and 67 genes were differentially expressed in rat intestinal mucosal and myocardial MVECs, respectively. Despite different altered gene expression patterns, many immune-associated genes were involved in both kinds of MVECs. The gene expression changes by microarray were confirmed by real-time reverse transcription-polymerase chain reaction. Transwell migration analysis indicated that the TEM of PBMC was increased by 146s antigens, which could be partially inhibited by blocking vascular cell adhesion molecule 1 in MVECs. This study suggests that MVECs play potential immunoregulatory roles in the immune response to FMD vaccines, one of which is influencing the TEM of immune cells.

Role of the endothelium in inflammatory bowel diseases

Inflammatory bowel diseases (IBD) are a complex group of diseases involving alterations in mucosal immunity and gastrointestinal physiology during both initiation and progressive phases of the disease. At the core of these alterations are endothelial cells, whose continual adjustments in structure and function coordinate vascular supply, immune cell emigration, and regulation of the tissue environment. Expansion of the endothelium in IBD (angiogenesis), mediated by inflammatory growth factors, cytokines and chemokines, is a hallmark of active gut disease and is closely related to disease severity. The endothelium in newly formed or inflamed vessels differs from that in normal vessels in the production of and response to inflammatory cytokines, growth factors, and adhesion molecules, altering coagulant capacity, barrier function and blood cell recruitment in injury. This review examines the roles of the endothelium in the initiation and propagation of IBD pathology and distinctive features of the intestinal endothelium contributing to these conditions.

Haemostatic system in inflammatory bowel diseases: New players in gut inflammation

Inflammation and coagulation constantly influence each other and are constantly in balance. Emerging evidence supports this statement in acute inflammatory diseases, such as sepsis, but it also seems to be very important in chronic inflammatory settings, such as inflammatory bowel disease (IBD). Patients with Crohn’s disease and ulcerative colitis have an increased risk of thromboembolic events, and several abnormalities concerning coagulation components occur in the endothelial cells of intestinal vessels, where most severe inflammatory abnormalities occur. The aims of this review are to update and classify the type of coagulation system abnormalities in IBD, and analyze the strict and delicate balance between coagulation and inflammation at the mucosal level. Recent studies on possible therapeutic applications arising from investigations on coagulation abnormalities associated with IBD pathogenesis will also be briefly presented and critically reviewed.

Cyclosporin A and atherosclerosis--cellular pathways in atherogenesis

Cyclosporin A (CsA) is an immunosuppressant drug widely used in organ transplant recipients and people with autoimmune disorders. Long term treatment with CsA is associated with many side effects including hyperlipidemia and an increased risk of atherosclerosis. While its immunosuppressive effects are closely linked to its effects on T cell activation via the inhibition of the nuclear factor of activated T cells (NFAT) pathway, the precise mechanisms underlying its cardiovascular effects appear to involve multiple pathways additional to those relevant for immunosuppression. These include inhibition of calcineurin activity and intracellular cyclophilin peptidylprolyl isomerase and chaperone activities, inhibition of pro-inflammatory extracellular cyclophilin A, and NFAT-independent transcriptional effects. CsA demonstrates complex effects on lipoprotein metabolism and bile acid production, and affects endothelial cells, smooth muscle cells and macrophages, all of which are critical to the atherosclerotic process. Interpretation of the available data is hampered as many experimental models are used to study the effects of CsA in vivo and in vitro, leading to diverse and often contradictory findings. In this review we will describe the cellular mechanisms related to CsA-induced hyperlipidemia and atherosclerosis, with a focus on identifying pro-atherogenic pathways that are distinct from those relevant to its immunosuppressant effects. The potential of CsA analogues to avoid such sequelae will be discussed.

Targeting signaling pathways with small molecules to treat autoimmune disorders

Chronic activation of immune responses, mediated by inflammatory mediators and involving different effector cells of the innate and acquired immune system characterizes autoimmune disorders, such as rheumatoid arthritis, inflammatory bowel disease, psoriasis and septic shock syndrome. MAPKs are crucial intracellular mediators of inflammation. MAPK inhibitors are attractive anti-inflammatory drugs, because they are capable of reducing the synthesis of inflammation mediators at multiple levels and are effective in blocking proinflammatory cytokine signaling. Janus kinase (JAK)/signal transducers and activators of transcription (STAT) pathway converts cytokine signals into genomic responses regulating proliferation and differentiation of the immune cells. JAK inhibitors are a new class of immunomodulatory agents with immunosuppressive, anti-inflammatory and antiallergic properties. This review discusses the rationale behind current strategies of targeting MAPK and JAK/STAT signaling pathways, and the overall effects of signal transduction inhibitors in animal models of inflammatory disorders. Signal transduction inhibitors are small molecules that can be administered orally, and initial results of clinical trials have shown clinical benefits in patients with chronic inflammatory disorders.

Thalidomide inhibits inflammatory and angiogenic activation of human intestinal microvascular endothelial cells (HIMEC)

The glutamic acid derivative thalidomide is a transcriptional inhibitor of TNF-alpha but is also known to affect human blood vessels, which may underlie its teratogenicity. Thalidomide has been used in the treatment of refractory Crohn's disease (CD), but the therapeutic mechanism is not defined. We examined the effect of thalidomide on primary cultures of human intestinal microvascular endothelial cells (HIMEC), the relevant endothelial cell population in inflammatory bowel disease (IBD), to determine its effect on endothelial activation, leukocyte interaction, and VEGF-induced angiogenesis. HIMEC cultures were pretreated with thalidomide before activation with either TNF-alpha/LPS or VEGF. A low-shear-stress flow adhesion assay with either U-937 or whole blood was used to assess HIMEC activation following TNF-alpha/LPS, and a Wright's stain identified adherent leukocytes. Expression of cell adhesion molecules (E-selectin, intercellular adhesion molecule-1, vascular cell adhesion molecule-1) was assessed using radioimmunoassay. Effects of thalidomide on NF-kappaB activation, cyclooxygenase (COX)-2, and inducible nitric oxide synthase (iNOS) expression in TNF-alpha/LPS-activated HIMEC were determined by RT-PCR and Western blotting. Thalidomide blocked adhesion of both U-937 and whole blood leukocytes by 50% in HIMEC, inhibiting binding of all classes of leukocytes. Thalidomide also blocked NF-kappaB and cell adhesion molecule expression in HIMEC. In marked contrast, thalidomide did not affect either iNOS or COX-2 expression, two key molecules that play a role in the downregulation of HIMEC activation. VEGF-induced HIMEC transmigration, growth, proliferation, tube formation, and Akt phosphorylation were significantly inhibited by thalidomide. In summary, thalidomide exerted a potent effect on HIMEC growth and activation, suggesting that it may also function via an endothelial mechanism in the treatment of CD.

Pichinde virus induces microvascular endothelial cell permeability through the production of nitric oxide

This report is the first to demonstrate infection of human endothelial cells by Pichinde virus (PIC). PIC infection induces an upregulation of the inducible nitric oxide synthase gene; as well as an increase in detectable nitric oxide (NO). PIC induces an increase in permeability in endothelial cell monolayers which can be abrogated at all measured timepoints with the addition of a nitric oxide synthase inhibitor, indicating a role for NO in the alteration of endothelial barrier function. Because NO has shown antiviral activity against some viruses, viral titer was measured after addition of the NO synthase inhibitor and found to have no effect in altering virus load in infected EC. The NO synthase inhibition also has no effect on levels of activated caspases induced by PIC infection. Taken together, these data indicate NO production induced by Pichinde virus infection has a pathogenic effect on endothelial cell monolayer permeability.

Vascular cell adhesion molecule-1 expression in human intestinal microvascular endothelial cells is regulated by PI 3-kinase/Akt/MAPK/NF-kappaB: inhibitory role of curcumin

Endothelial activation and surface expression of cell adhesion molecules (CAMs) is critical for binding and recruitment of circulating leukocytes in tissues during the inflammatory response. Endothelial CAM expression plays a critical role in the intestinal microvasculature in inflammatory bowel disease (IBD), as blockade of leukocyte alpha4-integrin binding by gut endothelial CAM ligands has therapeutic benefit in IBD. Mechanisms underlying expression of vascular cell adhesion molecule (VCAM)-1, a ligand for alpha4-integrin in primary cultures of human intestinal microvascular endothelial cells (HIMEC) has not been defined. We investigated the effect of curcumin, phosphatidylinositol 3-kinase (PI 3-kinase)/protein kinase B (Akt), and mitogen-activated protein kinase (MAPK) inhibitors on VCAM-1 expression and function in HIMEC. CAM expression was assessed and HIMEC-leukocyte adhesion was visualized under static and flow conditions. Western blotting and in vitro kinase assays were used to assess Akt and MAPK activation. Nuclear factor-kappaB (NF-kappaB) activation and nuclear translocation of its p65 subunit were determined. Tumor necrosis factor (TNF)-alpha/lipopolysaccharide (LPS)-induced VCAM-1 expression in HIMEC was suppressed by Akt small-interfering RNA, curcumin, and inhibitors of NF-kappaB (SN-50), p38 MAPK (SB-203580) and PI 3-kinase/Akt (LY-294002). VCAM-1 induction was partially suppressed by p44/42 MAPK (PD-098059) but unaffected by c-Jun NH2-terminal kinase (SP-600125) inhibition. Curcumin inhibited Akt/MAPK/NF-kappaB activity and prevented nuclear translocation of the p65 NF-kappaB subunit following TNF-alpha/LPS. At physiological shear stress, curcumin attenuated leukocyte adhesion to TNF-alpha/LPS-activated HIMEC monolayers. In conclusion, curcumin inhibited the expression of VCAM-1 in HIMECs through blockade of Akt, p38 MAPK, and NF-kappaB. Curcumin may represent a novel therapeutic agent targeting endothelial activation in IBD.

Flower extract of Panax notoginseng attenuates lipopolysaccharide-induced inflammatory response via blocking of NF-kappaB signaling pathway in murine macrophages

AIM OF THE STUDY

The root of Panax notoginseng (PN) is commonly used to treat chronic liver disease with its therapeutic abilities to stop haemorrhage in the circulation, while the PN flower (PN-F) is largely unknown in the biological activities on inflammation and mechanisms of its actions. In this study, the pharmacologic effects of PN-F methanol extract on inflammation were investigated to address potential therapeutic or toxic effects in LPS-stimulated mouse macrophage cells, RAW264.7 cells.

MATERIALS AND METHODS

Production of NO, PGE2 and pro-inflammatory cytokines (TNF-alpha and IL-1beta) in supernatant, the expression of iNOS, COX-2 and cytokines, the phosphorylation of MAPK molecules (ERK1/2, JNK and p38 MAPK), and the activation of NF-kappaB in PN-F extract were assayed in LPS-stimulated RAW264.7 cells.

RESULTS

PN-F extract significantly inhibited the productions of NO, PGE2, TNF-alpha and IL-1beta on the LPS-stimulated RAW264.7 cells. In addition, PN-F extract suppressed the mRNA and protein expressions of iNOS, COX-2, TNF-alpha and IL-1beta in LPS-stimulated RAW264.7 cells. The molecular mechanism of PN-F extract-mediated attenuation in RAW264.7 cells has close a relationship to suppressing the phosphorylation of MAPK molecules such as ERK1/2, JNK and p38 MAPK, and the translocation of NF-kappaB p65 subunit into nuclear.

CONCLUSION

These results indicate that PN-F extract inhibits LPS-induced inflammatory response via the blocking of NF-kappaB signaling pathway in macrophages, and demonstrated that PN-F extract possesses anti-inflammatory properties in vitro.

Prophylaxis against Pneumocystis pneumonia in patients with inflammatory bowel disease: toward a standard of care

Patients with Crohn's Disease and ulcerative colitis are increasingly treated with a host of immunomodulatory and immunosuppressive medications, including thiopurines and antibody-based biologic agents. Despite the known infectious complications associated with these therapies from the HIV and solid organ transplant literature, there are currently no well-defined concise guidelines to assist gastroenterologists and other physicians in the utility and indication for prophylaxis against Pneumocystis pneumonia and other infections in inflammatory bowel disease (IBD) patients. In this article, we discuss the evidence of various infections associated with immunocompromise in HIV/AIDS, organ transplantation, and in other immunocompromised states, and discuss the evidence for the efficacy and safety of various infectious prophylaxis protocols. In addition, we discuss the evidence for Pneumocystis and other infections in IBD patients treated with corticosteroids, azathioprine/6-MP, biologic agents and other therapies, and we present the case for various antibiotic (and antiviral) regimens to prevent such infections. Based on the review of the literature, this discussion represents a true call for guidelines for infection prophylaxis, to help guide gastroenterologists and all practitioners who care for the challenging population of IBD patients.

Increased arginase activity and endothelial dysfunction in human inflammatory bowel disease

Nitric oxide (.NO) generation from conversion of l-arginine to citrulline by nitric oxide synthase isoforms plays a critical role in vascular homeostasis. Loss of .NO is linked to vascular pathophysiology and is decreased in chronically inflamed gut blood vessels in inflammatory bowel disease (IBD; Crohn's disease and ulcerative colitis). Mechanisms underlying decreased .NO production in IBD gut microvessels are not fully characterized. Loss of .NO generation may result from increased arginase (AR) activity, which enzymatically competes with nitric oxide synthase for the common substrate l-arginine. We characterized AR expression in IBD microvessels and endothelial cells and its contribution to decreased .NO production. AR expression was assessed in resected gut tissues and human intestinal microvascular endothelial cells (HIMEC). AR expression significantly increased in both ulcerative colitis and Crohn's disease microvessels and submucosal tissues compared with normal. TNF-alpha/lipopolysaccharide increased AR activity, mRNA and protein expression in HIMEC in a time-dependent fashion. RhoA/ROCK pathway, a negative regulator of .NO generation in endothelial cells, was examined. The RhoA inhibitor C3 exoenzyme and the ROCK inhibitor Y-27632 both attenuated TNF-alpha/lipopolysaccharide-induced MAPK activation and blocked AR expression in HIMEC. A significantly higher AR activity and increased RhoA activity were observed in IBD submucosal tissues surrounding microvessels compared with normal control gut tissue. Functionally, inhibition of AR activity decreased leukocyte binding to HIMEC in an adhesion assay. Loss of .NO production in IBD microvessels is linked to enhanced levels of AR in intestinal endothelial cells exposed to chronic inflammation in vivo.

Differential effects of immunosuppressive drugs on T-cell motility

The best-characterized mechanism of the action of immunosuppressive drugs is to prevent T-cell clonal expansion, thus containing the magnitude of the ensuing immune response. As T-cell recruitment to the inflammatory site is another key step in the development of T-cell-mediated inflammation, we analyzed and compared the effects of two commonly used immunosuppressants, cyclosporin A (CsA) and the rapamycin-related compound SDZ-RAD, on the motility of human CD4+ T cells. We show that CsA, but not SDZ-RAD, inhibits T-cell transendothelial migration in vitro. CsA selectively impaired chemokine-induced T-cell chemotaxis while integrin-mediated migration was unaffected. The inhibition of T-cell chemotaxis correlated with reduced AKT/PKB but not ERK activation following exposure to the chemokine CXCL-12/SDF-1. In addition, CsA, but not SDZ-RAD, prevents some T-cell receptor-mediated effects on T-cell motility. Finally, we show that CsA, but not SDZ-RAD inhibits tissue infiltration by T cells in vivo. Our data suggest a prominent antiinflammatory role for CsA in T-cell-mediated tissue damage, by inhibiting T-cell trafficking into tissues in addition to containing clonal expansion.

Dickkopf homologs in squamous mucosa of esophagitis patients are overexpressed compared with Barrett's patients and healthy controls

OBJECTIVES

Esophageal mucosal response to acid exposure varies from minimal changes to erosions/ulcerations and Barrett's metaplasia. While differences in acid contact time have been suggested, the reason for these different responses is not completely understood. The aim of this study was to identify and compare gene expression differences between normal distal and proximal squamous esophageal mucosa (SM) in esophagitis patients with that of healthy controls and Barrett's patients.

METHODS

Gene microarray was performed on laser-capture microdissected epithelial cells isolated from biopsy specimens followed by real-time PCR. The effect of acidic pH (pH 4.5) on Dickkopf Homolog 1 (Dkk-1) expression in the human esophageal epithelial cell line (Het-1A) was determined.

RESULTS

Gene microarray analysis demonstrated that the upregulation of five genes in the distal compared with the proximal SM in esophagitis patients was greater than the healthy controls and Barrett's patients. Overexpression of Dkk-1 and Dkk-4 was further confirmed by real-time PCR. Dkk-1 and Dkk-4 mRNA levels in the distal SM of the esophagitis patients were 7.0- and 3.1-fold higher, respectively, than in the distal SM of the Barrett's patients and 4.1- and 4.1-fold higher than in healthy controls, respectively. Dkk-1 protein expression in the distal esophagitis SM was also higher than the Barrett's patients and healthy controls. Acidic pH exposure of Het-1A cells resulted in Dkk-1 upregulation at the level of both mRNA and protein.

CONCLUSIONS

Dkk-1 and Dkk-4 may potentially be involved in the development of different injuries in response to pathological gastroesophageal acid reflux.

Human esophageal microvascular endothelial cells respond to acidic pH stress by PI3K/AKT and p38 MAPK-regulated induction of Hsp70 and Hsp27

The heat shock response maintains cellular homeostasis following sublethal injury. Heat shock proteins (Hsps) are induced by thermal, oxyradical, and inflammatory stress, and they chaperone denatured intracellular proteins. Hsps also chaperone signal transduction proteins, modulating signaling cascades during repeated stress. Gastroesophageal reflux disease (GERD) affects 7% of the US population, and it is linked to prolonged esophageal acid exposure. GERD is characterized by enhanced and selective leukocyte recruitment from esophageal microvasculature, implying activation of microvascular endothelium. We investigated whether phosphatidylinositol 3-kinase (PI3K)/Akt and MAPK regulate Hsp induction in primary cultures of human esophageal microvascular endothelial cells (HEMEC) in response to acid exposure (pH 4.5). Inhibitors of signaling pathways were used to define the contribution of PI3K/Akt and MAPKs in the heat shock response and following acid exposure. Acid significantly enhanced phosphorylation of Akt and MAPKs in HEMEC as well as inducing Hsp27 and Hsp70. The PI3K inhibitor LY-294002, and Akt small interfering RNA inhibited Akt activation and Hsp70 expression in HEMEC. The p38 MAPK inhibitor (SB-203580) and p38 MAPK siRNA blocked Hsp27 and Hsp70 mRNA induction, suggesting a role for MAPKs in the HEMEC heat shock response. Thus acidic pH exposure protects HEMEC through induction of Hsps and activation of MAPK and PI3 kinase pathway. Acidic exposure increased HEMEC expression of VCAM-1 protein, but not ICAM-1, which may contribute to selective leukocyte (i.e., eosinophil) recruitment in esophagitis. Activation of esophageal endothelial cells exposed to acidic refluxate may contribute to GERD in the setting of a disturbed mucosal squamous epithelial barrier (i.e., erosive esophagitis, peptic ulceration).

Ciclosporin aggravates tissue damage in ischemia reperfusion-induced acute pancreatitis

OBJECTIVES

Ischemia reperfusion (I/R)-associated early graft pancreatitis is a major complication after pancreas transplantation. The influence of immunosuppressants on graft pancreatitis remains unclear. The aim of this study was to evaluate ciclosporin and tacrolimus in experimental pancreatic I/R.

METHODS

Moderate pancreatitis was induced in rats by I/R injury. Animals were assigned to 4 groups: (1) control without I/R, (2) I/R without therapy, (3) I/R + ciclosporin, or (4) I/R + tacrolimus. After 24 hours, pancreatic damage was evaluated by amylase, endothelin 1, thromboxane A2, and histology. Additionally, microcirculation was evaluated 12 hours after reperfusion by intravital microscopy.

RESULTS

I/R significantly increased amylase compared with controls, with maximum levels after ciclosporin treatment. Histology showed comparable tissue injury in control and tacrolimus-treated animals. Ciclosporin-treated animals developed significantly (P < 0.05) more inflammation and necrosis compared with the other groups. Erythrocyte velocity evaluated by intravital microscopy was reduced in all animals after I/R. This was significantly pronounced after ciclosporin application. There was a significant increase of adherent leukocytes and platelets in ciclosporin-treated animals compared with both other groups.

CONCLUSIONS

Tacrolimus does not negatively influence I/R-induced pancreatitis, whereas ciclosporin aggravates pancreatic tissue damage after I/R. These effects should be evaluated in the clinical setting of pancreas transplantation.

Dendritic cell adhesion is enhanced on endothelial cells preexposed to calcineurin inhibitors

Chronic rejection remains a major complication in solid organ transplantation. Host alloreactive T cells (TC) can be activated by donor dendritic cells (DCs; direct allorecognition) or by recipient DCs (indirect allorecognition). A fundamental aspect of DC function is vascular invasion to present donor antigens to recipient naive TC in secondary lymphoid organs. We investigated the impact of calcineurin inhibitors on DC binding and transmigration to allogeneic human microvascular endothelial cells (ECs) with and without blocking of specific adhesion molecules. Recipient immature DCs were generated by culturing CD14 human peripheral blood monocytes with GM-CSF and IL-4. DC adhesion and transmigration were investigated on allogeneic ECs preincubated with increasing concentrations of cyclosporine and tacrolimus. Experiments were repeated in the presence of blocking antibodies against LFA-1, PECAM-1, VCAM-1, and ICAM-1. Endothelial stimulation with cyclosporine A (100 and 300 ng/mL) and tacrolimus (15 ng/mL) significantly enhanced DC-EC adhesion and transmigration (P<0.01). LFA-1 blockade on DCs significantly reduced cyclosporine- and tacrolimus-induced DC adhesion (P<0.001). VCAM-1 blockade on ECs partially reversed cyclosporine-induced DC adhesion (P<0.001), whereas DC adhesion under tacrolimus exposure was significantly decreased by ICAM-1 (P<0.01) and PECAM-1 (P<0.001) blockade. DC binding and transmigration on allogeneic ECs exposed to calcineurin inhibitors is concentration-dependently increased. Different adhesion molecule patterns on ECs are responsible for enhanced DC invasion under cyclosporine and tacrolimus exposure. We speculate that long-term immunosuppression mediates enhanced invasion of recipient DCs to the donor organ and therefore may aggravate chronic rejection.

Alterations of Mesenchymal and Endothelial Cells in Inflammatory Bowel Diseases

The pathogenesis of complex chronic diseases like inflammatory bowel disease (IBD) can no longer be viewed as a one-way street in which classical immune cells have exclusive control over the initiation, duration and outcome of the disease. There is enough experimental evidence to demonstrate that nonimmune cells, among which are mucosal mesenchymal and endothelial cells, also play a decisive role by interacting with immune cells and establishing a two-way reciprocal exchange of signals and responses that dictate the ultimate outcome of inflammation. Smooth muscle cells and fibroblasts/myofibroblasts display a variety of immune functions and modulate the activity and survival of T-cells. Mucosal microvascular cells, through the expression of adhesion molecules and secretion of chemokines, regulate the quantity and quality of leukocytes transmigrating into the interstitial space. A number of receptor-ligand pairs are expressed by immune and nonimmune cells that control their functional interplay, but the CD40/CD40 ligand system may be the most effective because CD40 is expressed by activated muscle and endothelial cells, while the CD40 ligand is expressed by activated T-cells and platelets. The activation of this system in IBD can lead to the establishment of a continuous cycle of nonimmune cell-dependent, antigen-independent interactions that perpetuates gut inflammation.

Immunomodulatory benefits of cyclosporine A in inflammatory bowel disease

Etiopathogenesis of mucosal inflammation in inflammatory bowel disease remains a complex and enigmatic field; various factors (genetic, environmental and microbial) trigger an event that activates intestinal immune and nonimmune systems culminating in inflammation and tissue injury. Specifically, both innate and adaptive immune systems seem to play important roles in the pathophysiology of this disease. Cyclosporine A represents a macrolide immune modulator with primary inhibitory effects on T helper lymphocyte production of interleukin-2, and other cytokines leading to altered T-lymphocyte and B-lymphocyte function. The diversity of its therapeutic outcome reported in inflammatory bowel disease may be due to the intricate immuno-pathogenic profile of the disease and the variety of the applied dose-dependent courses of therapy. Cyclosporine A exerts additional actions on other components of the inflammatory infiltrate, including neutrophils and mast cells, thereby appearing to be a multi-dynamic therapeutic approach, although with potential drawbacks, that may be applied alone or combined with other immunomodulatory agents in inflammatory bowel disease patients. Because cyclosporine A induces apoptosis of T-lymphocytes responsible for perpetuation of the chronic inflammatory process in the disease with potential tumorigenic effect, it may exert a further inhibitory effect on cancer development in inflammatory bowel disease patients, and can be combined with other relative agents, such as rapamycin, which also promotes T-lymphocyte apoptosis. Therefore, recently established multifactorial action of cyclosporine A in relation to the pathogenesis of the disease can open new horizons for prospective, controlled trials in large cohorts, aiming to emphasize cyclosporine A's potential.

MAPK signalling pathways as molecular targets for anti-inflammatory therapy--from molecular mechanisms to therapeutic benefits

Excessive inflammation is becoming accepted as a critical factor in many human diseases, including inflammatory and autoimmune disorders, neurodegenerative conditions, infection, cardiovascular diseases, and cancer. Cerebral ischemia and neurodegenerative diseases are accompanied by a marked inflammatory reaction that is initiated by expression of cytokines, adhesion molecules, and other inflammatory mediators, including prostanoids and nitric oxide. This review discusses recent advances regarding the detrimental effects of inflammation, the regulation of inflammatory signalling pathways in various diseases, and the potential molecular targets for anti-inflammatory therapy. Mitogen-activated protein kinases (MAPKs) are a family of serine/threonine protein kinases that mediate fundamental biological processes and cellular responses to external stress signals. Increased activity of MAPK, in particular p38 MAPK, and their involvement in the regulation of the synthesis of inflammation mediators at the level of transcription and translation, make them potential targets for anti-inflammatory therapeutics. Inhibitors targeting p38 MAPK and JNK pathways have been developed, and preclinical data suggest that they exhibit anti-inflammatory activity. This review discusses how these novel drugs modulate the activity of the p38 MAPK and JNK signalling cascades, and exhibit anti-inflammatory effects in preclinical disease models, primarily through the inhibition of the expression of inflammatory mediators. Use of MAPK inhibitors emerges as an attractive strategy because they are capable of reducing both the synthesis of pro-inflammatory cytokines and their signalling. Moreover, many of these drugs are small molecules that can be administered orally, and initial results of clinical trials have shown clinical benefits in patients with chronic inflammatory disease.

Role of p38 in nitric oxide synthase and cyclooxygenase expression, and nitric oxide and PGE2 synthesis in human gingival fibroblasts stimulated with lipopolysaccharides

Periodontal disease, a gingival inflammatory disease caused by gram-negative bacteria, is the main cause of tooth loss. Lipopolysaccharides (LPS) present in bacterial cell walls induce human gingival fibroblasts' production of pro-inflammatory cytotoxins such as IL-1beta and TNFalpha. The goal of this study was to determine p38 role in the expression of inducible nitric oxide synthase enzyme (i-NOS) and cyclooxygenase (COX-2), as well as in PGE(2) and nitric oxide synthesis in human gingival fibroblasts challenged with LPS. We found that lipopolysaccharides induced a rapid and significant increase in p38 phosphorylation. After interruption of p38 transduction pathway by pre-treatment with inhibitor SB203580, no response to stimulation with LPS was observed; i-NOS expression and nitric oxide synthesis was completely blocked. However, p38 inhibition only partially blocked COX-2 expression and PGE2 synthesis. We conclude that p38 is critically involved in i-NOS induction, and that it participates in COX-2 expression and in PGE2 synthesis.

Effect of cyclosporin A on cell adhesion molecules and leukocyte-endothelial cell interactions in experimental colitis

BACKGROUND

Cyclosporin A (CsA) is an immunosuppressive agent that is believed to act primarily through effects on T-helper lymphocyte function and proliferation. The aim of this study was to investigate whether modulation of leukocyte recruitment and expression of cell adhesion molecules contribute to the therapeutic efficacy of CsA in a model of experimental colitis.

METHODS

The therapeutic effects of CsA were assessed in mice with dextran sulfate sodium-induced colitis. Leukocyte-endothelial cell interactions were determined in colonic venules by intravital microscopy. The expression of cell adhesion molecules intercellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule 1 (VCAM-1), and mucosal addressin cell adhesion molecule 1 (MAd-CAM-1) was measured by the radiolabeled antibody technique.

RESULTS

Treatment with CsA (4 mg/kg/day) significantly improved the clinical course of colitis, decreasing weight loss, diarrhea, rectal bleeding, disease activity index, colon weight, and colonic shortening. Microscopic damage score, myeloperoxidase activity, tumor necrosis factor alpha (TNF-alpha), and interleukin-6 in colonic tissue were significantly diminished by CsA. CsA also significantly reduced ICAM-1 and VCAM-1, but not MAdCAM-1, expression in colitic mice. TNF-alpha-induced ICAM-1 and VCAM-1 expression in primary cultures of human umbilical vein endothelial cells was reduced by co-incubation with CsA. The reduction in adhesion molecule expression was followed by a marked decrease in leukocyte adhesion in colonic venules of colitic mice.

CONCLUSIONS

CsA ameliorates experimental colitis in mice. Reduced adhesion molecule expression resulting from diminished pro-inflammatory cytokine production and from a direct effect of CsA in endothelial cells decreases leukocyte recruitment into the inflamed intestine, contributing to this protective effect.

Mechanisms of MAdCAM-1 gene expression in human intestinal microvascular endothelial cells

Mucosal addressin cell adhesion molecule-1 (MAdCAM-1) is a homing receptor preferentially expressed on gut-associated endothelial cells that plays a central role in leukocyte traffic into the mucosal immune compartment. Although the molecular mechanisms underlying endothelial ICAM-1 or E-selectin expression have been intensively investigated, the mechanisms that regulate human MAdCAM-1 expression have not been defined. We report MAdCAM-1 gene and protein expression in primary cultures of human intestinal microvascular endothelial cells (HIMEC) that was not demonstrated in human umbilical vein endothelial cells. Similar to ICAM-1 and E-selectin expression, MAdCAM-1 gene expression in HIMEC was inducible with TNF-alpha, IL-1beta, or LPS activation. However, in striking contrast to ICAM-1 and E-selectin expression, MAdCAM-1 mRNA and protein expression in HIMEC was heavily dependent on culture duration and/or cellular density, suggesting a prominent role for cell-cell interaction among these endothelial cells in the expression of the mucosal addressin. MAdCAM-1 expression was inhibited by both SN-50 (NF-kappaB inhibitor) and LY-294002 [phosphatidylinositol 3-kinase (PI3-K) inhibitor], whereas ICAM-1 and E-selectin expression was inhibited by SN-50 but not by LY-294002. The Akt phosphorylation by TNF-alpha or LPS was greater at higher cell density, demonstrating a pattern similar to that of MAdCAM-1 expression. NF-kappaB activation was not affected by cellular density in HIMEC. MAdCAM-1 expression in human gut endothelial cells is regulated by distinct signaling mechanisms involving both NF-kappaB and PI3-K/Akt. These data also suggest that PI3-K/Akt is involved in the gut-specific differentiation of HIMEC, which results in expression of the mucosal addressin MAdCAM-1.

Decay-accelerating factor induction on vascular endothelium by vascular endothelial growth factor (VEGF) is mediated via a VEGF receptor-2 (VEGF-R2)- and protein kinase C-alpha/epsilon (PKCalpha/epsilon)-dependent cytoprotective signaling pathway and is inhibited by cyclosporin A

Decay-accelerating factor (DAF), a membrane-bound complement regulatory protein, is up-regulated on endothelial cells (ECs) following treatment with vascular endothelial growth factor (VEGF), providing enhanced protection from complement-mediated injury. We explored the signaling pathways involved in this response. Incubation of human umbilical vein ECs with VEGF induced a 3-fold increase in DAF expression. Inhibition by flk-1 kinase inhibitor SU1498 and failure of placental growth factor (PlGF) to up-regulate DAF confirmed the role of VEGF-R2. The response was also blocked by pretreatment with phospholipase C-gamma (PLCgamma) inhibitor U71322 and protein kinase C (PKC) antagonist GF109203X. In contrast, no effect was seen with nitric oxide synthase inhibitor N(G)-monomethyl-l-arginine (l-NMMA). Use of PKC agonists and isozyme-specific pseudosubstrate peptide antagonists suggested a role for PKCalpha and -epsilon in VEGF-mediated DAF up-regulation. This was confirmed by transfection of ECs with PKCalpha and -epsilon dominant-negative constructs, which in combination completely abrogated induction of DAF by VEGF. In contrast, LY290042, a phosphoinositide 3-kinase (PI3K) inhibitor, significantly augmented DAF expression, suggesting a negative regulatory role for phosphoinositide 3-kinase. The widely used immunosuppressive drug cyclosporin A (CsA) inhibited DAF induction by VEGF in a dose-dependent manner. The VEGF-induced DAF expression was functionally effective, significantly reducing complement-mediated EC lysis, and this cytoprotective effect was reversed by CsA. These data provide evidence for a VEGF-R2-, phospholipase C-gamma-, and PKCalpha/epsilon-mediated cytoprotective pathway in ECs. This may represent an important mechanism for the maintenance of vascular integrity during chronic inflammation involving complement activation. Moreover, inhibition of this pathway by CsA may play a role in CsA-mediated vascular injury.

Dynamic regulation of gene expression by the Flt-1 kinase and Matrigel in endothelial tubulogenesis

A nontubulogenic endothelial cell line, NP31, can be transformed by the active form of the Flt-1 kinase (BCR-FLTm1) into Tb3 cells, which show a tubulogenic property only when cultured in Matrigel. By utilizing this strict dependence of NP31 on BCR-FLTm1 and Matrigel for experimental angiogenesis, we performed microarray analyses under several conditions and found 97 genes whose dynamically regulated profiles of gene expression are divided into nine groups, in two major clusters. In one major cluster, gene expression is interdependently regulated by BCR-FLTm1 or Matrigel. The second major cluster contains genes whose expression patterns under BCR-FLTm1 influence are reversed by Matrigel. Based on these gene expression patterns in NP31 driven by BCR-FLTm1 and/or Matrigel, we propose a model in which sequential and alternate stimulation by BCR-FLTm1 and Matrigel induces cooperative regulation of subsets of genes. Microarray analyses of Tb3 under 11 different conditions revealed 5 candidate genes whose gene expression regulation is most closely associated with tubulogenesis.