PMN transendothelial migration decreases nuclear NFkappaB in IL-1beta-activated endothelial cells: role of PECAM-1

Personalized risk predictor for acute cellular rejection in lung transplant using soluble CD31

We evaluated the contribution of artificial intelligence in predicting the risk of acute cellular rejection (ACR) using early plasma levels of soluble CD31 (sCD31) in combination with recipient haematosis, which was measured by the ratio of arterial oxygen partial pressure to fractional oxygen inspired (PaO₂/FiO₂) and respiratory SOFA (Sequential Organ Failure Assessment) within 3 days of lung transplantation (LTx). CD31 is expressed on endothelial cells, leukocytes and platelets and acts as a "peace-maker" at the blood/vessel interface. Upon nonspecific activation, CD31 can be cleaved, released, and detected in the plasma (sCD31). The study included 40 lung transplant recipients, seven (17.5%) of whom experienced ACR. We modelled the plasma levels of sCD31 as a nonlinear dependent variable of the PaO₂/FiO₂ and respiratory SOFA over time using multivariate and multimodal models. A deep convolutional network classified the time series models of each individual associated with the risk of ACR to each individual in the cohort.

Carbon monoxide mechanism of protection against renal ischemia and reperfusion injury

Carbon monoxide is quickly moving past its historic label as a molecule once feared, to a therapeutic drug that modulates inflammation. The development of carbon monoxide releasing molecules and utilization of heme oxygenase-1 inducers have shown carbon monoxide to be a promising therapy in reducing renal ischemia and reperfusion injury and other inflammatory diseases. In this review, we will discuss the developments and application of carbon monoxide releasing molecules in renal ischemia and reperfusion injury, and transplantation. We will review the anti-inflammatory mechanisms of carbon monoxide in respect to mitigating apoptosis, suppressing dendritic cell maturation and signalling, inhibiting toll-like receptor activation, promoting anti-inflammatory responses, and the effects on renal vasculature.

Role and Potential Mechanism of Heme Oxygenase-1 in Intestinal Ischemia-Reperfusion Injury

Intestinal ischemia-reperfusion (IR) injury is a complex, multifactorial, and pathophysiological condition with high morbidity and mortality, leading to serious difficulties in treatment, especially in humans. Heme oxygenase (HO) is the rate-limiting enzyme involved in heme catabolism. HO-1 (an inducible form) confers cytoprotection by inhibiting inflammation and oxidation. Furthermore, nuclear factor-erythroid 2-related factor 2 (Nrf2) positively regulates HO-1 transcription, whereas BTB and CNC homolog 1 (Bach1) competes with Nrf2 and represses its transcription. We investigated the role and potential mechanism of action of HO-1 in intestinal IR injury. Intestinal ischemia was induced for 45 min followed by 4 h of reperfusion in wild-type, Bach1-deficient, and Nrf2-deficient mice, and a carbon monoxide (CO)-releasing molecule (CORM)-3 was administered. An increase in inflammatory marker levels, nuclear factor-κB (NF-κB) activation, and morphological impairments were observed in the IR-induced intestines of wild-type mice. These inflammatory changes were significantly attenuated in Bach1-deficient mice or those treated with CORM-3, and significantly exacerbated in Nrf2-deficient mice. Treatment with an HO-1 inhibitor reversed this attenuation in IR-induced Bach1-deficient mice. Bach1 deficiency and treatment with CORM-3 resulted in the downregulation of NF-κB activation and suppression of adhesion molecules. Together, Bach1, Nrf2, and CO are valuable therapeutic targets for intestinal IR injury.

The psychoactive drug of abuse mephedrone differentially disrupts blood-brain barrier properties

Background

Synthetic cathinones are a category of psychostimulants belonging to the growing number of designer drugs also known as “Novel Psychoactive Substances” (NPS). In recent years, NPS have gained popularity in the recreational drug market due to their amphetamine-like stimulant effects, low cost, ease of availability, and lack of detection by conventional toxicology screening. All these factors have led to an increase in NPS substance abuse among the young adults, followed by spike of overdose-related fatalities and adverse effects, severe neurotoxicity, and cerebral vascular complications. Much remains unknown about how synthetic cathinones negatively affect the CNS and the status of the blood-brain barrier (BBB).

Methods

We used in vitro models of the BBB and primary human brain microvascular endothelial cells (hBMVEC) to investigate the effects of the synthetic cathinone, 4-methyl methcathinone (mephedrone), on BBB properties.

Results

We showed that mephedrone exposure resulted in the loss of barrier properties and endothelial dysfunction of primary hBMVEC. Increased permeability and decreased transendothelial electrical resistance of the endothelial barrier were attributed to changes in key proteins involved in the tight junction formation. Elevated expression of matrix metalloproteinases, angiogenic growth factors, and inflammatory cytokines can be explained by TLR-4-dependent activation of NF-κB signaling.

Conclusions

In this first characterization of the effects of a synthetic cathinone on human brain endothelial cells, it appears clear that mephedrone-induced damage of the BBB is not limited by the disruption of the barrier properties but also include endothelial activation and inflammation. This may especially be important in comorbid situations of mephedrone abuse and HIV-1 infections. In this context, mephedrone could negatively affect HIV-1 neuroinvasion and NeuroAIDS progression.

Metabolic adaptations of cells at the vascular-immune interface during atherosclerosis

Metabolic reprogramming is a physiological cellular adaptation to intracellular and extracellular stimuli that couples to cell polarization and function in multiple cellular subsets. Pathological conditions associated to nutrients overload, such as dyslipidaemia, may disturb cellular metabolic homeostasis and, in turn, affect cellular response and activation, thus contributing to disease progression. At the vascular/immune interface, the site of atherosclerotic plaque development, many of these changes occur. Here, an intimate interaction between endothelial cells (ECs), vascular smooth muscle cells (VSMCs) and immune cells, mainly monocytes/macrophages and lymphocytes, dictates physiological versus pathological response. Furthermore, atherogenic stimuli trigger metabolic adaptations both at systemic and cellular level that affect the EC layer barrier integrity, VSMC proliferation and migration, monocyte infiltration, macrophage polarization, lymphocyte T and B activation. Rewiring cellular metabolism by repurposing “metabolic drugs” might represent a pharmacological approach to modulate cell activation at the vascular immune interface thus contributing to control the immunometabolic response in the context of cardiovascular diseases.

CD31 as a Therapeutic Target in Atherosclerosis

The potential of CD31 as a therapeutic target in atherosclerosis has been considered ever since its cloning in the 1990s, but the exact role played by this molecule in the biologic events underlying atherosclerosis has remained controversial, resulting in the stalling of any therapeutic perspective. Due to the supposed cell adhesive properties of CD31, specific monoclonal antibodies and recombinant proteins were regarded as blocking agents because their use prevented the arrival of leukocytes at sites of acute inflammation. However, the observed effect of those compounds likely resulted from the engagement of the immunomodulatory function of CD31 signaling. This was acknowledged only later though, upon the discovery of CD31's 2 intracytoplasmic tyrosine residues called immunoreceptor tyrosine inhibitory motifs. A growing body of evidence currently points at a therapeutic potential for CD31 agonists in atherothrombosis. Clinical observations show that CD31 expression is altered at the surface of leukocytes infiltrating unhealed atherothrombotic lesions and that the physiological immunomodulatory functions of CD31 are lost at the surface of blood leukocytes in patients with acute coronary syndromes. On the contrary, translational studies using candidate therapeutic molecules in laboratory animals have provided encouraging results: synthetic peptides administered to atherosclerotic mice as systemic drugs in the acute phases of atherosclerotic complications favor the healing of wounded arteries, whereas the immobilization of CD31 agonist peptides onto coronary stents implanted in farm pigs favors their peaceful integration within the coronary arterial wall.

Carbon monoxide-releasing molecule-3 (CORM-3) offers protection in an in vitro model of compartment syndrome

OBJECTIVE

Limb compartment syndrome (CS), a complication of trauma, results in muscle necrosis and cell death; ischemia and inflammation contribute to microvascular dysfunction and parenchymal injury. Carbon monoxide-releasing molecule-3 (CORM-3) has been shown to protect microvascular perfusion and reduce inflammation in animal models of CS. The purpose of the study was to test the effect of CORM-3 in human in vitro CS model, allowing exploration of the mechanism(s) of CO protection and potential development of pharmacologic treatment.

METHODS

Confluent human vascular endothelial cells (HUVECs) were stimulated for 6 h with serum isolated from patients with CS. Intracellular oxidative stress (production of reactive oxygen species (ROS)) apoptosis, transendothelial resistance (TEER), polymorphonuclear leukocyte (PMN) activation and transmigration across the monolayer in response to the CS stimulus were assessed. All experiments were performed in the presence of CORM-3 (100 μM) or its inactive form, iCORM-3.

RESULTS

CS serum induced a significant increase in ROS, apoptosis and endothelial monolayer breakdown; it also increased PMN superoxide production, leukocyte rolling and adhesion/transmigration. CORM-3 completely prevented CS-induced ROS production, apoptosis, PMN adhesion, rolling and transmigration, while improving monolayer integrity.

CONCLUSION

CORM-3 offers potent anti-oxidant and anti-inflammatory effects, and may have a potential application to patients at risk of developing CS.

Mechanotransduction, immunoregulation, and metabolic functions of CD31 in cardiovascular pathophysiology

Biomechanical changes in the heart and vessels drive rapid and dynamic regulation of blood flow, a vital process for meeting the changing metabolic needs of the peripheral tissues at any given point in time. The fluid movement of the blood exerts haemodynamic stress upon the solid elements of the cardiovascular system: the heart, vessels, and cellular components of the blood. Cardiovascular diseases can lead to prolonged mechanical stress, such as cardiac remodelling during heart failure or vascular stiffening in atherosclerosis. This can lead to a significantly reduced or increasingly turbulent blood supply, inducing a shift in cellular metabolism that, amongst other effects, can trigger the release of reactive oxygen species and initiate a self-perpetuating cycle of inflammation and oxidative stress. CD31 is the most abundant constitutive co-signalling receptor glycoprotein on endothelial cells, which line the cardiovascular system and form the first-line of cellular contact with the blood. By associating with most endothelial receptors involved in mechanosensing, CD31 regulates the response to biomechanical stimuli. In addition, by relocating in the lipid rafts of endothelial cells as well as of cells stably interacting with the endothelium, including leucocytes and platelets, CD31–CD31 trans-homophilic engagement guides and restrains platelet and immune cell accumulation and activation and at sites of damage. In this way, CD31 is at the centre of mediating mechanical, metabolic, and immunological changes within the circulation and provides a single target that may have pleiotropic beneficial effects.

Platelet Endothelial Cell Adhesion Molecule-1 and Oligodendrogenesis: Significance in Alcohol Use Disorders

Alcoholism is a chronic relapsing disorder with few therapeutic strategies that address the core pathophysiology. Brain tissue loss and oxidative damage are key components of alcoholism, such that reversal of these phenomena may help break the addictive cycle in alcohol use disorder (AUD). The current review focuses on platelet endothelial cell adhesion molecule 1 (PECAM-1), a key modulator of the cerebral endothelial integrity and neuroinflammation, and a targetable transmembrane protein whose interaction within AUD has not been well explored. The current review will elaborate on the function of PECAM-1 in physiology and pathology and infer its contribution in AUD neuropathology. Recent research reveals that oligodendrocytes, whose primary function is myelination of neurons in the brain, are a key component in new learning and adaptation to environmental challenges. The current review briefly introduces the role of oligodendrocytes in healthy physiology and neuropathology. Importantly, we will highlight the recent evidence of dysregulation of oligodendrocytes in the context of AUD and then discuss their potential interaction with PECAM-1 on the cerebral endothelium.

Carbon Monoxide-Releasing Molecule-401 Suppresses Polymorphonuclear Leukocyte Migratory Potential by Modulating F-Actin Dynamics

Carbon monoxide-releasing molecules (CORMs) suppress inflammation by reducing polymorphonuclear leukocyte (PMN) recruitment to the affected organs. We investigated modulation of PMN-endothelial cell adhesive interactions by water-soluble CORM-401 using an experimental model of endotoxemia in vitro. Human umbilical vein endothelial cells (HUVEC) grown on laminar-flow perfusion channels were stimulated with 1 μg/mL lipopolysaccharide for 6 hours and perfused with 100 μmol/L CORM-401 (or inactive compound iCORM-401)-pretreated PMN for 5 minutes in the presence of 1.0 dyn/cm² shear stress.

HUVEC

PMN co-cultures were perfused for additional 15 minutes with PMN-free medium containing CORM-401/inactive CORM-401. The experiments were videorecorded (phase-contrast microscopy), and PMN adhesion/migration were assessed off-line. In parallel, CORM-401-dependent modulation of PMN chemotaxis, F-actin expression/distribution, and actin-regulating pathways [eg, p21-activated protein kinases (PAK1/2) and extracellular signal-regulated kinase (ERK)/C-Jun N-terminal kinase (JNK) mitogen-activated protein kinases (MAPK)] were assessed in response to N-formyl-methionyl-leucyl-phenylalanine (fMLP) stimulation. Pretreating PMN with CORM-401 did not suppress PMN adhesion to HUVEC, but significantly reduced PMN transendothelial migration (P < 0.0001) and fMLP-induced PMN chemotaxis (ie, migration directionality and velocity). These changes were associated with CORM-401-dependent suppression of F-actin levels/cellular distribution and fMLP-induced phosphorylation of PAK1/2 and ERK/JNK MAPK (P < 0.05). CORM-401 had no effect on p38 MAPK activation. In summary, this study demonstrates, for the first time, CORM-401-dependent suppression of neutrophil migratory potential associated with modulation of PAK1/2 and ERK/JNK MAPK signaling and F-actin dynamics.

PECAM-1-dependent heme oxygenase-1 regulation via an Nrf2-mediated pathway in endothelial cells

The antioxidant enzyme heme oxygenase (HO)-1, which catalyses the first and rate-limiting step of heme degradation, has major anti-inflammatory and immunomodulatory effects via its cell-type-specific functions in the endothelium. In the current study, we investigated whether the key endothelial adhesion and signalling receptor PECAM-1 (CD31) might be involved in the regulation of HO-1 gene expression in human endothelial cells (ECs). To this end PECAM-1 expression was down-regulated in human umbilical vein ECs (HUVECs) by an adenoviral vector-based knockdown approach. PECAM-1 knockdown markedly induced HO-1, but not the constitutive HO isoform HO-2. Nuclear translocation of the transcription factor NF-E2-related factor-2 (Nrf2), which is a master regulator of the inducible antioxidant cell response, and intracellular levels of reactive oxygen species (ROS) were increased in PECAM-1-deficient HUVECs, respectively. PECAM-1-dependent HO-1 regulation was also examined in PECAM-1 over-expressing Chinese hamster ovary and murine L-cells. Endogenous HO-1 gene expression and reporter gene activity of transiently transfected luciferase HO-1 promoter constructs with Nrf2 target sequences were decreased in PECAM-1 over-expressing cells. Moreover, a regulatory role of ROS for HO-1 regulation in these cells is demonstrated by studies with the antioxidant N-acetylcysteine and exogenous hydrogenperoxide. Finally, direct interaction of PECAM-1 with a native complex of its binding partner NB1 (CD177) and serine proteinase 3 (PR3) from human neutrophils, markedly induced HO-1 expression in HUVECs. Taken together, we demonstrate a functional link between HO-1 gene expression and PECAM-1 in human ECs, which might play a critical role in the regulation of inflammation.

Crosstalk between reticular adherens junctions and platelet endothelial cell adhesion molecule-1 regulates endothelial barrier function

OBJECTIVE

Endothelial cells provide a barrier between the blood and tissues, which is reduced during inflammation to allow selective passage of molecules and cells. Adherens junctions (AJ) play a central role in regulating this barrier. We aim to investigate the role of a distinctive 3-dimensional reticular network of AJ found in the endothelium.

METHODS AND RESULTS

In endothelial AJ, vascular endothelial-cadherin recruits the cytoplasmic proteins β-catenin and p120-catenin. β-catenin binds to α-catenin, which links AJ to actin filaments. AJ are usually described as linear structures along the actin-rich intercellular contacts. Here, we show that these AJ components can also be organized in reticular domains that contain low levels of actin. Reticular AJ are localized in areas where neighboring cells overlap and encompass the cell adhesion receptor platelet endothelial cell adhesion molecule-1 (PECAM-1). Superresolution microscopy revealed that PECAM-1 forms discrete structures distinct from and distributed along AJ, within the voids of reticular domains. Inflammatory tumor necrosis factor-α increases permeability by mechanisms that are independent of actomyosin-mediated tension and remain incompletely understood. Reticular AJ, but not actin-rich linear AJ, were disorganized by tumor necrosis factor-α. This correlated with PECAM-1 dispersal from cell borders. PECAM-1 inhibition with blocking antibodies or small interfering RNA specifically disrupted reticular AJ, leaving linear AJ intact. This disruption recapitulated typical tumor necrosis factor-α-induced alterations of barrier function, including increased β-catenin phosphorylation, without altering the actomyosin cytoskeleton.

CONCLUSIONS

We propose that reticular AJ act coordinately with PECAM-1 to maintain endothelial barrier function in regions of low actomyosin-mediated tension. Selective disruption of reticular AJ contributes to permeability increase in response to tumor necrosis factor-α.

Inflammatory response in microvascular endothelium in sepsis: role of oxidants

Sepsis, as a severe systemic inflammatory response to bacterial infection, represents a major clinical problem. It is characterized by the excessive production of reactive oxygen species (ROS) both in the circulation and in the affected organs. The excessive generation of ROS inevitably leads to oxidative stress in the microvasculature and has been implicated as a causative event in a number of pathologies including sepsis. In this review, we focus on the role of oxidative and nitrosative stress during the early onset of sepsis. Changes in microvascular endothelial cells, the cell type that occurs in all organs, are discussed. The mechanisms underlying septic induction of oxidative and nitrosative stresses, the functional consequences of these stresses, and potential adjunct therapies for microvascular dysfunction in sepsis are identified.

Potential utility of melatonin as an antioxidant during pregnancy and in the perinatal period

Reactive oxygen species (ROS) play a critical role in the pathogenesis of various diseases during pregnancy and the perinatal period. Newborns are more prone to oxidative stress than individuals later in life. During pregnancy, increased oxygen demand augments the rate of production of ROS and women, even during normal pregnancies, experience elevated oxidative stress compared with non-pregnant women. ROS generation is also increased in the placenta during preeclampsia. Melatonin is a highly effective direct free-radical scavenger, indirect antioxidant, and cytoprotective agent in human pregnancy and it appears to be essential for successful pregnancy. This suggests a role for melatonin in human reproduction and in neonatal pathologies (asphyxia, respiratory distress syndrome, sepsis, etc.). This review summarizes current knowledge concerning the role for melatonin in human pregnancy and in the newborn. Numerous studies agree that short-term melatonin therapy is highly effective in reducing complications during pregnancy and in the neonatal period. No significant toxicity or treatment-related side effects with long-term melatonin therapy in children and adults have been reported. Treatment with melatonin might result in a wide range of health benefits, including improved quality of life and reduced healthcare costs.

Carbon monoxide-releasing molecule CORM-3 suppresses vascular endothelial cell SOD-1/SOD-2 activity while up-regulating the cell surface levels of SOD-3 in a heparin-dependent manner

The role of CO in the modulation of antioxidant enzyme function has not been investigated, yet. In this study we assessed the effects and potential mechanisms of the ruthenium-based water-soluble CO-releasing molecule CORM-3 in the modulation of superoxide dismutase (SOD) activity/binding in vascular endothelial cells (HUVECs). To this end, HUVECs were treated with CORM-3 (100 μM) and assessed for total SOD activity in cell lysates (cell-associated SOD activity) and cell culture supernatants (soluble SOD). In parallel, release/binding of extracellular SOD (SOD-3) in the absence or presence of heparin (1-10 IU/ml), a key factor regulating SOD-3 cell-surface binding, was investigated. In addition, the effects of CORM-3 on the modulation of purified SOD-1 and SOD-2 activity in a cell-free system were also assessed. The results obtained indicate that CORM-3 effectively suppresses the activity of both purified SOD-1 and SOD-2. These findings were accompanied by CORM-3-dependent attenuation of total cell-associated SOD activity (without affecting SOD-1/SOD-2 protein expression) and a subsequent increase in ROS production (DHR123 oxidation) in HUVECs. In parallel, a concomitant increase in soluble-SOD activity (due to increased SOD-3 release from the cell surface) was observed in the cell culture supernatants. However, in the presence of heparin, total cell-associated SOD activity was significantly increased by CORM-3, because of increased binding of SOD-3 to HUVECs. Taken together these findings indicate for the first time that CORM-3 modulates both the activity of intracellular SOD (i.e., SOD-1 and SOD-2) and the binding of extracellular SOD (SOD-3) to the cell surface.

Selective induction of cell adhesion molecules by proinflammatory mediators in human cardiac microvascular endothelial cells in culture

Pro-inflammatory mediators can dramatically alter many responses of cultured endothelial cells in vitro, which are relevant to understanding the role played by the endothelium in inflammation in vivo. The aim of this study was to determine the ability of a comprehensive array of pro-inflammatory stimuli to modulate Cell Adhesion Molecule (CAM) expression in cultures of human microvascular cardiac endothelial cells (HMVEC.c). Cell ELISA, immunocy-tochemistry and flow cytometry were used to measure the CAM expressions in HMVEC.c in response to interleukins, TNF-α and LPS. Passage matched HMVEC.c from different donors showed different CAM expression profiles, confirming inherent variability in endothelial cells. Endothelial cells from different parts of the vasculature are exposed to different cytokines and thus different protein expression profiles. A thorough understanding of these innate differences in expression pattern of the microvasculatures of cardiac tissues might allow us the opportunity to target these tissues selectively.

PECAM-1: conflicts of interest in inflammation

Platelet endothelial cell adhesion molecule-1 (PECAM-1, CD31) is a cell adhesion and signaling receptor that is expressed on hematopoietic and endothelial cells. PECAM-1 is vital to the regulation of inflammatory responses, as it has been shown to serve a variety of pro-inflammatory and anti-inflammatory functions. Pro-inflammatory functions of PECAM-1 include the facilitation of leukocyte transendothelial migration and the transduction of mechanical signals in endothelial cells emanating from fluid shear stress. Anti-inflammatory functions include the dampening of leukocyte activation, suppression of pro-inflammatory cytokine production, and the maintenance of vascular barrier integrity. Although PECAM-1 has been well-characterized and studied, the mechanisms through which PECAM-1 regulates these seemingly opposing functions, and how they influence each other, are still not completely understood. The purpose of this review, therefore, is to provide an overview of the pro- and anti-inflammatory functions of PECAM-1 with special attention paid to mechanistic insights that have thus far been revealed in the literature in hopes of gaining a clearer picture of how these opposing functions might be integrated in a temporal and spatial manner on the whole organism level. A better understanding of how inflammatory responses are regulated should enable the development of new therapeutics that can be used in the treatment of acute and chronic inflammatory disorders.

Carbon monoxide liberated from CO-releasing molecule (CORM-2) attenuates ischemia/reperfusion (I/R)-induced inflammation in the small intestine

CORM-released CO has been shown to be beneficial in resolution of acute inflammation. The acute phase of intestinal ischemia-reperfusion (I/R) injury is characterized by oxidative stress-related inflammation and leukocyte recruitment. In this study, we assessed the effects and potential mechanisms of CORM-2-released CO in modulation of inflammatory response in the small intestine following I/R-challenge. To this end mice (C57Bl/6) small intestine were challenged with ischemia by occluding superior mesenteric artery (SMA) for 45 min. CORM-2 (8 mg/kg; i.v.) was administered immediately before SMA occlusion. Sham operated mice were injected with vehicle (0.25% DMSO). Inflammatory response in the small intestine (jejunum) was assessed 4 h following reperfusion by measuring tissue levels of TNF-alpha protein (ELISA), adhesion molecules E-selectin and ICAM-1 (Western blot), NF-kappaB activation (EMSA), along with PMN tissue accumulation (MPO assay) and leukocyte rolling/adhesion in the microcirculation of jejunum (intravital microscopy). The obtained results indicate that tissue levels of TNF-alpha, E-selectin and ICAM-1 protein expression, activation of NF-kappaB, and subsequent accumulation of PMN were elevated in I/R-challenged jejunum. The above changes were significantly attenuated in CORM-2-treated mice. Taken together these findings indicate that CORM-2-released CO confers anti-inflammatory effects by interfering with NF-kappaB activation and subsequent up-regulation of vascular pro-adhesive phenotype in I/R-challenged small intestine.

The anti-inflammatory actions of platelet endothelial cell adhesion molecule-1 do not involve regulation of endothelial cell NF-kappa B

PECAM-1 is a cell adhesion and signaling receptor that is expressed on many hematopoietic cells and at endothelial cell-cell junctions. Accumulating evidence from a number of in vitro and in vivo model systems suggests that PECAM-1 suppresses cytokine production and vascular permeability induced by a wide range of inflammatory stimuli. In several of these models of inflammatory disease, endothelial, and not leukocyte or platelet, PECAM-1 conferred protection against inflammatory insult. However, the mechanism by which endothelial PECAM-1 functions as an anti-inflammatory protein is poorly understood. It was recently suggested that PECAM-1 exerts its anti-inflammatory effects in endothelial cells by inhibiting the activity of NF-kappaB, a proinflammatory transcription factor. To confirm and extend these observations, we examined the effect of engaging, cross-linking, or expressing PECAM-1 on NF-kappaB activation in a variety of human cells. PECAM-1 had no effect on the phosphorylation of the NF-kappaB inhibitory protein, IkappaBalpha; on the nuclear translocation of NF-kappaB; on the suppression of cytokine-induced transcriptional activation of an NF-kappaB luciferase reporter plasmid; or on the cytokine-stimulated upregulation of ICAM-1, an NF-kappaB target gene, in endothelial cells. Taken together, these studies strongly suggest that the anti-inflammatory actions of PECAM-1 in endothelial cells are not likely to involve its regulation of NF-kappaB.

Mediators released from LPS-challenged lungs induce inflammatory responses in liver vascular endothelial cells and neutrophilic leukocytes

The systemic inflammatory response plays an important role in the progression of acute lung injury (ALI) to multiple organ dysfunction syndrome (MODS). However, the role of lung-derived inflammatory mediators in induction of the inflammatory response in remote organs is poorly understood. To address the above, we investigated the effects of lung inflammation on induction of inflammatory response(s) in the liver in vitro. Inflammation in mouse lungs was induced by intranasal administration of lipopolysaccharide (LPS; 1 mg/ml) followed by mechanical ventilation using the isolated perfused mouse lung method to obtain and characterize lung perfusate from the pulmonary circulation. LPS administration to mouse lungs resulted in an increased release of inflammation-relevant cytokines and chemokines into the perfusate (Luminex assay) compared with the saline-controls. Subsequently, primary mouse liver vascular endothelial cells (LVEC) or mouse polymorphonuclear leukocytes (PMN) in vitro were stimulated with the perfusate obtained from saline- or LPS-challenged lungs and assessed for various inflammation-relevant end points. The obtained results indicate that stimulation of LVEC with perfusate obtained from LPS-challenged lungs results in 1) reactive oxygen species (ROS) production; 2) activation of NF-kappaB; and 3) expression of E-selectin, ICAM-1, and VCAM-1 and a subsequent increase in PMN rolling and adhesion to LVEC. In addition, perfusate from LPS-challenged lung induced activation of PMN with respect to increased ROS production and upregulation of cell surface levels of adhesion molecules MAC-1 and VLA-4. Heat-inactivation of the perfusate obtained from LPS-challenged lungs was very effective in suppressing increased proadhesive phenotype (i.e., E-selectin and ICAM-1 expression) in LVEC, whereas targeted inhibition (immunoneutralization) of TNF-alpha and/or IL-6 in LPS-lung perfusate had no effect. Taken together, these findings indicate that multiple proinflammatory mediators (proteinaceous in nature) released from inflamed lungs act synergistically to induce systemic activation of circulating PMN and promote inflammatory responses in liver vascular endothelial cells.

Lansoprazole, a proton pump inhibitor, mediates anti-inflammatory effect in gastric mucosal cells through the induction of heme oxygenase-1 via activation of NF-E2-related factor 2 and oxidation of kelch-like ECH-associating protein 1

Induction of heme oxygenase-1 (HO-1) expression has been associated with cytoprotective and anti-inflammatory actions of lansoprazole, a proton pump inhibitor, but the underlying molecular mechanisms remain largely unresolved. In this study, we investigate the role of transcriptional NF-E2-related factor 2 (Nrf2), its phosphorylation/activation, and oxidation of Kelch-like ECH-associating protein 1 (Keap1) in lansoprazole-induced HO-1 up-regulation using cultured gastric epithelial cells (rat gastric mucosal cell line, RGM-1). HO-1 expression of RGM-1 cells was markedly enhanced in a time- and dose-dependent manner by the treatment with lansoprazole, and this up-regulation of HO-1 contributed to the inhibition of chemokine production from stimulated RGM-1 cells. Transfection of Nrf2-siRNA suppressed the lansoprazole-induced HO-1. An electrophoretic mobility shift assay showed increases in the nuclear translocation and stress-response elements (StRE) binding activity of Nrf2 proteins in RGM-1 cells treated with lansoprazole. Furthermore, in RGM-1 cells transfected with HO-1 enhancer luciferase reporter plasmid containing mutant StRE, lansoprazole-induced HO-1 reporter gene activity was diminished. Lansoprazole promoted the phosphorylation of extracellular signal-regulated kinase (ERK), and lansoprazole-induced HO-1 up-regulation was suppressed by U0126, an ERK-specific inhibitor. Phosphorylated Nrf2 protein was detected in the phosphoprotein fraction purified by a Pro-Q Diamond Phosphoprotein Enrichment kit. Finally, an oxidative form of the Keap1 protein was detected in lansoprazole-treated RGM-1 cells by analyzing S-oxidized proteins using biotinylated cysteine as a molecular probe. These results indicate that lansoprazole up-regulates HO-1 expression in rat gastric epithelial cells, and the up-regulated HO-1 contributes to the anti-inflammatory effects of the drug. Phosphorylation of ERK and Nrf2, activation and nuclear translocation of Nrf2, and oxidation of Keap1 are all involved in the lansoprazole-induced HO-1 up-regulation.

CORM-3-derived CO modulates polymorphonuclear leukocyte migration across the vascular endothelium by reducing levels of cell surface-bound elastase

Recently, it has been shown that carbon monoxide (CO)-releasing molecule (CORM)-released CO can suppress inflammation. In this study, we assessed the effects and potential mechanisms of a ruthenium-based water-soluble CO carrier [tricarbonylchloroglycinate-ruthenium(II) (CORM-3)] in the modulation of polymorphonuclear leukocyte (PMN) inflammatory responses in an experimental model of sepsis. Sepsis in mice was induced by cecal ligation and puncture. CORM-3 (3 mg/kg iv) was administered 15 min after the induction of cecal ligation and puncture. PMN accumulation in the lung (myeloperoxidase assay), bronchoalveolar lavage (BAL) fluid, and lung vascular permeability (protein content in BAL fluid) were assessed 6 h later. In in vitro experiments, human PMNs were primed with LPS (10 ng/ml) and subsequently stimulated with formyl-methionyl-leucylphenylalanine (fMLP; 100 nM). PMN production of ROS (L-012/dihydrorhodamine-123 oxidation), degranulation (release of elastase), and PMN rolling, adhesion, and migration to/across human umbilical vein endothelial cells (HUVECs) were assessed in the presence or absence of CORM-3 (1-100 muM). The obtained results indicated that systemically administered CORM-3 attenuates PMN accumulation and vascular permeability in the septic lung. Surprisingly, in in vitro experiments, treatment of PMNs with CORM-3 further augmented LPS/fMLP-induced ROS production and the release of elastase. The latter effects, however, were accompanied by an inability of PMNs to mobilize elastase to the cell surface (plasma membrane), an event required for efficient PMN transendothelial migration. The CORM-3-induced decrease in cell surface levels of elastase was followed by decreased PMN rolling/adhesion to HUVECs and complete prevention of PMN migration across HUVECs. In contrast, treatment of HUVECs with CORM-3 had no effect on PMN transendothelial migration. Taken together, these findings indicate that, in sepsis, CORM3-released CO, while further amplifying ROS production and degranulation of PMNs, concurrently reduces the levels of cell surface-bound elastase, which contributes to suppressed PMN transendothelial migration.

Oxidative stress of the newborn in the pre- and postnatal period and the clinical utility of melatonin

Newborns, and especially those delivered preterm, are probably more prone to oxidative stress than individuals later in life. Also during pregnancy, increased oxygen demand augments the rate of production of reactive oxygen species (ROS) and women, even with normal pregnancies, experience elevated oxidative stress and lipid peroxidation compared with nonpregnant women. Also, there appears to be an increase in ROS generation in the placenta of pre-eclamptic women. In comparison with healthy adults, newborn infants have lower levels of plasma antioxidants such as vitamin E, beta-carotene, and sulphydryl groups, lower levels of plasma metal binding proteins including ceruloplasmin and transferrin, and reduced activity of erythrocyte superoxide dismutase. This review summarizes conditions of newborns where there is elevated oxidative stress. Included in this group of conditions is asphyxia, respiratory distress syndrome and sepsis and the review also summarizes the literature related to clinical trials of antioxidant therapies and of melatonin, a highly effective antioxidant and free radical scavenger. The authors document there is general agreement that short-term melatonin therapy may be highly effective and that it has a remarkably benign safety profile, even when neonates are treated with pharmacological doses. Significant complications with long-term melatonin therapy in children and adults also have not been reported. None of the animal studies of maternal melatonin treatment or in postnatal life have shown any treatment-related side effects. The authors conclude that treatment with melatonin might result in a wide range of health benefits, improved quality of life and reduced healthcare costs and may help reduce complications in the neonatal period.

Astaxanthin protects mesangial cells from hyperglycemia-induced oxidative signaling

Astaxanthin (ASX) is a carotenoid that has potent protective effects on diabetic nephropathy in mice model of type 2 diabetes. In this study, we investigated the protective mechanism of ASX on the progression of diabetic nephropathy using an in vitro model of hyperglycemia, focusing on mesangial cells. Normal human mesangial cells (NHMCs) were cultured in the medium containing normal (5 mM) or high (25 mM) concentrations of D-glucose. Reactive oxygen species (ROS) production, the activation of nuclear transcription factors such as nuclear factor kappa B (NFkappaB) and activator protein-1 (AP-1), and the expression/production of transforming growth factor-beta 1 (TGFbeta(1)) and monocyte chemoattractant protein-1 (MCP-1) were evaluated in the presence or absence of ASX. High glucose (HG) exposure induced significant ROS production in mitochondria of NHMCs, which resulted in the activation of transcription factors, and subsequent expression/production of cytokines that plays an important role in the mesangial expansion, an important event in the pathogenesis of diabetic nephropathy. ASX significantly suppressed HG-induced ROS production, the activation of transcription factors, and cytokine expression/production by NHMCs. In addition, ASX accumulated in the mitochondria of NHMCs and reduced the production of ROS-modified proteins in mitochondria. ASX may prevent the progression of diabetic nephropathy mainly through ROS scavenging effect in mitochondria of mesangial cells and thus is expected to be very useful for the prevention of diabetic nephropathy.

Gene expression of endothelial cells due to interleukin-1 beta stimulation and neutrophil transmigration

During the inflammatory response, endothelial cell (EC) functions and mechanics change dramatically. To understand these responses, the authors analyzed changes in EC gene expression in an in vitro model of inflammation using cDNA microarrays. After interleukin-1 beta (IL1beta) stimulation, over 2500 genes were differentially expressed, of which approximately 2000 had not been previously identified by microarray studies of IL1beta stimulation in human umbilical vein endothelial cells (HUVECs). Functional grouping of these genes according to gene ontologies revealed genes associated with apoptosis, cell cycle, nuclear factor (NF)-kappa B cascade, chemotaxis, and immune response. Interestingly, claudin-1, known to exist in endothelial cell-cell junctions was up-regulated, but claudin-5 and occludin, which also exist in EC junctions, were down-regulated. Pre-b-cell colony enhancing factor (PBEF), a cytokine which may play a role in regulating endothelial permeability, was also up-regulated following IL1beta stimulation. Neutrophil transmigration across IL1beta-stimulated ECs did not induce changes in EC gene expression as strongly as IL1beta stimulation alone. Nineteen genes after 1 h and 22 genes after 3 h of neutrophil application were differentially expressed. These results indicate that, in terms of transcriptional effects on ECs, neutrophil transmigration is a relatively small perturbation in comparison to the background of large scale changes induced in ECs by cytokine stimulation. Supplementary materials are available for this article. Go to the publisher's online edition of Endothelium for the following free supplementary resources: supplementary figures and tables.

Cell type-specific aspects in biocompatibility testing: the intercellular contact in vitro as an indicator for endothelial cell compatibility

Endothelial cells cover the inner surface of blood vessels and form the interface between the blood and the tissues. Endothelial cells are involved in regulating barrier function, which is maintained by the interendothelial cell contacts. These interendothelial cell contacts are established by the interaction of different molecules. The maintenance of the barrier requires an appropriate signalling between these molecules. Thus, a number of different signalling pathways are integrated within interendothelial contacts. Since endothelial cells are important in tissue-implant interactions (especially for stent materials) this study examines the expression pattern of different interendothelial contact molecules to determine the usefulness in the analysis of biocompatibility in vitro. The effects of different pro-inflammatory and toxic stimuli and contact of human microvascular endothelial cells to metallic surfaces were examined for their impact on the pattern of interendothelial contact molecules. Striking modifications in the arrangement of these molecules were induced and the mode of modification was dependent on the tested compound. Thus, examining the pattern of expression of specific interendothelial contact molecules in vitro may be useful for testing the endothelial cell compatibility of biomaterials and their corrosion products.

Expression of podoplanin in the mouse salivary glands

OBJECTIVE

Podoplanin is one of the most highly expressed lymphatic-specific genes. Here, we report the distribution of cells expressing podoplanin in mouse salivary glands.

DESIGN

We immunohistochemically investigated the distribution of cells expressing podoplanin in mouse major salivary glands by laser-scanning microscopy. The expression of endothelial cell marker PECAM-1 was tested to discriminate lymphatic endothelium from salivary gland cells, and myoepithelial cells were identified by an antibody for P-cadherin.

RESULTS

The podoplanin expression was rarely found in acini of the parotid gland but clearly found at the basal portion of acini in the submandibular and sublingual glands. The number of portion reacted with anti-podoplanin is greater in the sublingual gland than in the submandibular gland. The expression was also found at the basal portion of ducts in all major salivary glands. The P-cadherin expression was rarely found in acini of the parotid gland but found in acini of the sublingual gland and on ducts in parotid and sublingual glands, corresponding to the area of podoplanin expression.

CONCLUSIONS

It was suggested that the acinar and myoepithelial cells in the salivary glands have the ability to express podoplanin, and that the expression may be concerned with the mucous saliva excretion.

Carbon monoxide liberated from carbon monoxide-releasing molecule CORM-2 attenuates inflammation in the liver of septic mice

Recent studies suggest that exogenously administered CO is beneficial for the resolution of acute inflammation. In this study, we assessed the role of CO liberated from a systemically administered tricarbonyldichlororuthenium-(II)-dimer (CORM-2) on modulation of liver inflammation during sepsis. Polymicrobial sepsis in mice was induced by cecal ligation and perforation (CLP). CORM-2 (8 mg/kg iv) was administered immediately after CLP induction, and neutrophil [polymorphonuclear leukocyte (PMN)] tissue accumulation, activation of transcription factor, NF-kappaB, and changes in adhesion molecule ICAM-1 expression (inflammation-relevant markers) were assessed in murine liver 24 h later. In addition, the effects and potential mechanisms of CORM-2-released CO in modulation of vascular endothelial cell proinflammatory responses were assessed in vitro. To this end, human umbilical vein endothelial cells (HUVEC) were stimulated with LPS (1 microg/ml) in the presence or absence of CORM-2 (10-100 microM) and production of intracellular reactive oxygen species (ROS), (DHR123 oxidation) and NO (DAF-FM nitrosation) and subsequent activation of NF-kappaB were assessed 4 h later. In parallel, expression of ICAM-1 and inducible NO synthase (iNOS) proteins along with PMN adhesion to LPS-challenged HUVEC were also assessed. Induction of CLP resulted in increased PMN accumulation, ICAM-1 expression, and activation of NF-kappaB in the liver of septic mice. These effects were significantly attenuated by systemic administration of CORM-2. In in vitro experiments, CORM-2-released CO attenuated LPS-induced production of ROS and NO, activation of NF-kappaB, increase in ICAM-1 and iNOS protein expression and PMN adhesion to LPS-stimulated HUVEC. Taken together, these findings indicate that CO released from systemically administered CORM-2 provides anti-inflammatory effects by interfering with NF-kappaB activation and subsequent downregulation of proadhesive vascular endothelial cell phenotype in the liver of septic mice.

The proinflammatory phenotype of PECAM-1-deficient mice results in atherogenic diet-induced steatohepatitis

The severity of nonalcoholic steatohepatitis (NASH) is determined by environmental and genetic factors, the latter of which are incompletely characterized. Platelet endothelial cell adhesion molecule-1 (PECAM-1) is a 130-kDa transmembrane glycoprotein expressed on blood and vascular cells. In the present study, we provide data for the novel finding that genetic deficiency of PECAM-1 potentiates the development and progression of NASH. We found that the rate of development and severity of diet-induced NASH are markedly enhanced in PECAM-1-deficient [knockout (KO)] mice relative to wild-type (WT) mice, as measured by histological and biochemical evaluation. Livers from KO mice exhibited typical histological features of NASH, including macrovesicular fat accumulation, hepatocyte injury with infiltration of inflammatory cells, fibrosis, and heightened oxidative stress. Alanine aminotransferase, a marker for liver injury, was also significantly higher in KO compared with WT mice. Consistent with a role for PECAM-1 as a suppressor of proinflammatory cytokines, plasma levels of inflammatory cytokines, including TNF-alpha and monocyte chemoattractant protein-1 (MCP-1), were also significantly higher in KO compared with WT mice. These findings are the first to show that the PECAM-1-deficient mouse develops progressive nonalcoholic fatty liver disease (NAFLD), supporting a role for PECAM-1 as a negative regulator of NAFLD progression. Future examination of recently identified PECAM-1 allelic isoforms in humans as potential risk factors for developing NASH may be warranted.

Effects of TNF-alpha on leukocyte adhesion molecule expressions in cultured human lymphatic endothelium

TNF-alpha alters leukocyte adhesion molecule expression of cultured endothelial cells like human umbilical vein endothelial cells (HUVEC). This study was designed to investigate the changes in vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1), and platelet endothelial cell adhesion molecule-1 (PECAM-1) expression with TNF-alpha stimulation in cultured human neonatal dermal lymphatic endothelial cells (HNDLEC). The real-time quantitative PCR analysis on HNDLEC showed that TNF-alpha treatment leads to increases of VCAM-1 and ICAM-1 mRNAs to the 10.8- and 48.2-fold levels of untreated cells and leads to a reduction of PECAM-1 mRNA to the 0.42-fold level of untreated cells. Western blot and immunohistochemical analysis showed that TNF-alpha leads to VCAM-1 and ICAM-1 expressions that were inhibited by antiserum to human TNF receptor or by AP-1 inhibitor nobiletin. In flow cytometry analysis, the number of VCAM-1- and ICAM-1-positive cells increased, and PECAM-1-positive cells decreased with TNF-alpha treatment. Regarding protein amounts produced in cells and amounts expressed on the cell surface, VCAM-1 and ICAM-1 increased in HNDLEC and HUVEC, and PECAM-1 decreased in HNDLEC in a TNF-alpha concentration-dependent manner. VCAM-1, ICAM-1, and PECAM-1 protein amounts in TNF-alpha-stimulated cells were lower in HNDLEC than in HUVEC. This suggests that the lymphatic endothelium has the TNF-alpha-induced signaling pathway, resulting in increased VCAM-1 and ICAM-1 expression to a weaker extent than blood endothelium and PECAM-1 reduction to a stronger extent than blood endothelium.

Methylparaben potentiates UV-induced damage of skin keratinocytes

For many years, methylparaben (MP) has been used as a preservative in cosmetics. In this study, we investigated the effects of ultraviolet-B (UVB) exposure on MP-treated human skin keratinocytes. HaCaT keratinocyte was cultured in MP-containing medium for 24h, exposed to UVB (15 or 30 mJ/cm(2)) and further cultured for another 24h. Subsequent cellular viability was quantified by MTT-based assay and cell death was qualified by fluorescent microscopy and flow cytometry. Oxidative stress, nitric oxide (NO) production and cellular lipid peroxidation were measured using fluorescent probes. In addition, activation of nuclear factor kappa B and activator protein-1 was assessed by electro-mobility gel-shift assay. Practical concentrations of MP (0.003%) had a little or no effect on cellular viability, oxidative stress, NO production, lipid peroxidation and activation of nuclear transcription factors in HaCaT keratinocytes. Low-dose UVB also had little or no effect on these parameters in HaCaT keratinocytes. However, UVB exposure significantly increased cell death, oxidative stress, NO production, lipid peroxidation and activation of transcription factors in MP-treated HaCaT keratinocytes. These results indicate that MP, which has been considered a safe preservative in cosmetics, may have harmful effects on human skin when exposed to sunlight.

Suppression of atherogenesis by delivery of TGFbeta1ACT using adeno-associated virus type 2 in LDLR knockout mice

TGFbeta(1) deficiency has been attributed to the development of atherosclerosis. There is, however, little direct evidence for this concept. To examine this hypothesis, low-density lipoprotein receptor knockout (LDLR(-/-)) mice were injected via tail vein with recombinant adeno-associated virus type 2 (rAAV) carrying a bioactive TGFbeta(1) mutant (AAV/TGFbeta1ACT, n=10) or granulocyte-macrophage-colony stimulating factor (AAV/GM-CSF, n=10, a negative control) or saline (n=9, control), and then put on a high cholesterol diet. At 18 weeks, blood lipids were found to be similarly elevated in all LDLR(-/-) mice. TGFbeta1ACT and GM-CSF (DNA, mRNA, and protein) were highly expressed in the tissues of mice given TGFbeta1ACT or AAV/GM-CSF, respectively, showing sustained transfection following gene delivery by the systemic route. Saline-treated and AAV/GM-CSF-treated LDLR(-/-) mice showed extensive areas of atherosclerotic lesion formation. There was evidence of intense oxidative stress (nitrotyrosine staining), inflammation (CD68 staining), and expression of adhesion molecules and the ox-LDL receptor LOX-1 (gene array analysis) in the atherosclerotic tissues. Importantly, atherosclerotic lesion formation was markedly inhibited in the LDLR(-/-) mice given AAV/TGFbeta1ACT. Expression of adhesion molecules and LOX-1, oxidative stress, and inflammatory response all were inhibited in the mice given AAV/TGFbeta1ACT (P<0.05 vs. saline-treated or GM-CSF-treated LDLR(-/-) mice). These data for the first time demonstrate that systemic delivery of TGFbeta1ACT gene via AAV can inhibit formation of atherosclerotic lesions, possibly via anti-inflammatory and anti-oxidant mechanisms. These findings suggest a novel view of TGFbeta(1) in atherogenesis and a potential new gene therapy for treatment of atherosclerosis.

Detection of differentially expressed glycogenes in trabecular meshwork of eyes with primary open-angle glaucoma

PURPOSE

To identify differentially expressed glycogenes in trabecular meshwork (TM) of eyes with primary open-angle glaucoma (POAG).

METHODS

Total RNA was isolated from TM of cadaveric eyes derived from donors with diagnosed glaucomas of different etiologies and from normal control subjects. RNA was amplified and hybridized to the GLYCOv2 oligonucleotide microarray that contains probes for carbohydrate-binding proteins, glycosyltransferases, and other genes involved in the regulation of glycosylation. Statistical analysis was used to identify differentially expressed genes between normal and POAG samples.

RESULTS

This study revealed that POAG TM and normal TM have distinct gene expression profiles. Of the 2001 genes on the array, 19 genes showed differential expression of greater than 1.4-fold in POAG. Mimecan and activinA, which have been shown to be upregulated in models of glaucoma, were both found to be elevated in POAG TM. Many genes were identified for the first time to be differentially regulated in POAG. Among the upregulated genes were: (1) cell adhesion molecules including platelet endothelial cell adhesion molecule-1 and P-selectin, both of which are targets of NFkappaB, which has been shown to be activated in glaucomatous TM; (2) lumican, a core protein of keratan sulfate proteoglycans; and (3) the receptor for IL6, a cytokine that has been shown to be upregulated in TM in response to elevated intraocular pressure. Among the downregulated genes were chondroitin-4-O-sulfotransferase involved in the synthesis of chondroitin sulfate chains and the receptor for PDGFbeta, a growth factor that has been shown to stimulate both TM cell proliferation and phagocytic activity. Results for several genes were confirmed by RTq-PCR.

CONCLUSIONS

Microarray technology was used to show, for the first time, that POAG TM has a distinct glycogene expression profile. Differentially expressed glycogenes identified in this study have not been previously investigated for their role in the pathogenesis of POAG and thus are novel factors for further study of the mechanism of the disease and for their possible use as diagnostic markers.

PECAM-1 and gelatinase B coexist in vascular cuffs of multiple sclerosis lesions

In multiple sclerosis (MS), the matrix metalloprotease (MMP) gelatinase B/MMP-9 and platelet endothelial cell adhesion molecule (PECAM)-1 have both been implicated in trans-endothelial infiltration of leucocytes into the brain, but their functional connection has not yet been investigated. We investigated the expression of gelatinase B and PECAM-1 in post mortem brains of MS patients by immunohistochemistry. Because increased soluble PECAM-1 serum levels have been observed in MS patients, we also tested in vitro whether this could be due to cleavage of PECAM-1 by gelatinase B or matrilysin-1/MMP-7. Constitutive expression of PECAM-1 was found on brain endothelial cells, whilst in active MS lesions cell-bound PECAM-1 was highly up-regulated on foamy macrophages in perivascular infiltrates and co-localized with gelatinase B. However, human THP-1 monocyte-bound or soluble recombinant PECAM-1 were both resistant to proteolytic cleavage by gelatinase B or matrilysin-1 in vitro, as demonstrated by Western blot analysis and flow cytometry. These results suggest that PECAM-1 and gelatinase B may complement each other during the transmigration of the blood-brain barrier by mononuclear cells.

Nitric oxide in wound-healing

Modulation of the complex process of wound-healing remains a surgical challenge. Little improvement beyond controlling infection, gentle tissue handling, and debridement of necrotic tissue has been had in the modern era. However, increasing appreciation of the process from a biomolecular perspective offers the potential for making significant strides in wound modulation. The bioactive molecule nitric oxide was found to have wide-ranging impact on cellular activities, including the cellular responses engendered by wound healing. Current research suggests that nitric oxide and several nitric oxide donors can exert biologic effects, although the particular net responses of cells contributing to wound repair are context-dependent.

Aging and the endothelium

One link between aging and endothelial function is the inflammatory response. On one hand, the latter shortens the biological engaged by activated leukocytes against invaders or stressing agents. On the other hand, the surveyed tissues become targets of the toxicity of reactive oxygen species, ROS. The ensuing regeneration is source of transcriptional infidelity, leading to the alteration of the repaired tissue. Hence, the toll of inflammatory stress consists in premature senescence of cell and tissues. This hypothesis is discussed in the present review, which focuses on the molecular targets relevant for cancer and degenerative diseases, both tributary to an inflammatory environment and taking advantage from the consequences of cell and tissue dysfunctions characteristic of aging. Eventually, adaptation to stress, whatever its origin -inflammatory and/or psychosocial-is discussed. Basal nitric oxide (NO) release, such as provided through moderate exercise, seems to be the most potent guardian against immune, nervous and cardiovascular over-stimulation. Tissue regeneration is also obtained by circulating endothelial progenitors able to recognize the damaged tissue. To avoid post-inflammatory alterations resulting in detrimental changes of tissues and organs, the pharmacological protection of endothelium by agents able to modulate its activation seems crucial to us.

Tumor necrosis factor-alpha-induced cytokine-induced neutrophil chemoattractant-1 (CINC-1) production by rat gastric epithelial cells: role of reactive oxygen species and nuclear factor-kappaB

Rat cytokine-induced neutrophil chemoattractant-1 (CINC-1), a counterpart of the human growth-regulated oncogene product (GRO), has been suggested to participate in neutrophil recruitment in an experimental model of gastritis in rat. However, the mechanism(s) involved in regulation of CINC-1 production by the gastric mucosa remains unclear. The aim of this study was to investigate the mechanism(s) of CINC-1 production by rat gastric mucosa in vitro. All experiments were performed using rat normal gastric mucosal cell line (RGM-1). RGM-1s were stimulated with tumor necrosis factor (TNF)-alpha, and CINC-1 mRNA levels (reverse transcription-polymerase chain reaction) and protein secretion (enzyme-linked immunosorbent assay) were assessed. The production of reactive oxygen species (ROS) and nuclear factor (NF)-kappaB activation (translocation to the nuclei) in response to TNF-alpha stimulation was evaluated using fluorescence microscopy in the presence or absence of the inhibitors of mitochondrial electron flow and NF-kappaB activation. Stimulation of RGM-1 cells with TNF-alpha resulted in an increase in intracellular oxidative stress, NF-kappaB translocation to the nuclei, and up-regulation of CINC-1 mRNA and protein, which was prevented by interfering with mitochondria-dependent ROS production and NF-kappaB activation. Taken together, these findings indicate that CINC-1, a counterpart of the human GRO, production by rat gastric epithelial cells in response to TNF-alpha stimulation is an oxidant stress-mediated and NF-kappaB-dependent event.