The regulation of ICAM-1 and LFA-1 interaction by autacoids and statins: a novel strategy for controlling inflammation and immune responses

Portal Hypertension in Malnutrition and Sarcopenia in Decompensated Cirrhosis-Pathogenesis, Implications and Therapeutic Opportunities

Malnutrition and sarcopenia are highly prevalent in patients with decompensated cirrhosis and are associated with poorer clinical outcomes. Their pathophysiology is complex and multifactorial, with protein-calorie malnutrition, systemic inflammation, reduced glycogen stores and hormonal imbalances all well reported. The direct contribution of portal hypertension to these driving factors is however not widely documented in the literature. This review details the specific mechanisms by which portal hypertension directly contributes to the development of malnutrition and sarcopenia in cirrhosis. We summarise the existing literature describing treatment strategies that specifically aim to reduce portal pressures and their impact on nutritional and muscle outcomes, which is particularly relevant to those with end-stage disease awaiting liver transplantation.

Immunotherapy in leukaemia

Leukaemia is the common name for a group of malignant diseases of the haematopoietic system with complex classifications and characteristics. Remarkable progress has been made in basic research and preclinical studies for acute leukaemia compared to that of the many other types/subtypes of leukaemia, especially the exploration of the biological basis and application of immunotherapy in acute myeloid leukaemia (AML) and B-cell acute lymphoblastic leukaemia (B-ALL). In this review, we summarize the basic approaches to immunotherapy for leukaemia and focus on the research progress made in immunotherapy development for AML and ALL. Importantly, despite the advances made to date, big challenges still exist in the effectiveness of leukaemia immunotherapy, especially in AML. Therefore, we use AML as an example and summarize the mechanisms of tumour cell immune evasion, describe recently reported data and known therapeutic targets, and discuss the obstacles in finding suitable treatment targets and the results obtained in recent clinical trials for several types of single and combination immunotherapies, such as bispecific antibodies, cell therapies (CAR-T-cell treatment), and checkpoint blockade. Finally, we summarize novel immunotherapy strategies for treating lymphocytic leukaemia and clinical trial results.

The association between visceral adiposity with systemic inflammation, oxidative stress, and risk of post-surgical adhesion

Abdominal and pelvic adhesions are common post-operative complications. Despite new medical technologies, these adhesions are appearing to be unavoidable and little is known about their causation; for example, why certain patients/or tissues are more prone to adhesions. There have been no clinical studies about increasing the risk adhesions in obese patients, but there is some evidence about the molecular mechanisms involving visceral fat (VF) that may lead to profibrotic conditions. VF is an endocrine/inflammatory organ which produces many biologically active molecules such as adipokines and inflammatory cytokines. Inflammatory conditions, oxidative stress, and the expression some fibrotic molecules in the VF may induce pathological conditions in the abdominal cavity that predispose to the formation of fibrotic bands.

Silencing GOLGA8B inhibits cell invasion and metastasis by suppressing STAT3 signaling pathway in lung squamous cell carcinoma

Changes to some Golgi subfamily member proteins are reported to be involved in tumor metastasis. However, the functional role and potential mechanism of the Golgi A8 family member B (GOLGA8B) in lung squamous cell carcinoma (LUSC) remains unknown. In the present study, GOLGA8B expression was detected using qRT-PCR, Western blot, and immunohistochemistry (IHC). In vivo animal experiments and in vitro functional assays were performed to explore the function of GOLGA8B in LUSC. Luciferase assays were performed to investigate the underlying targets of GOLGA8B in LUSC. GOLGA8B was shown to be highly expressed in LUSC metastasis tissue, and significantly associated with the distant metastasis-free survival of LUSC patients. Loss-of-function assays indicated that silencing GOLGA8B suppressed LUSC cell tumorigenesis in vivo and weakened in vitro invasion and migration. GOLGA8B silencing-induced inhibition of invasion and migration was associated with the inactivation of STAT3 signaling. Importantly, these results showed that the number of circulating tumor cells (CTCs) was markedly higher in the GOLGA8B silencing group than in the control vector group. GOLGA8B expression was positively associated with p-STAT3 expression in LUSC tissue. Study findings revealed a novel mechanism by which GOLGA8B promotes tumor metastasis in LUSC cells and suggests that this protein could be a promising target for antitumor metastasis therapy in LUSC patients.

Ruscogenin protects against deoxynivalenol-Induced hepatic injury by inhibiting oxidative stress, inflammation, and apoptosis through the Nrf2 signaling pathway: An In vitro study

Background

Deoxynivalenol (DON) is a trichothecene mycotoxin with demonstrated cytotoxicity in several cell lines and animals, primarily owing to inflammation and reactive oxygen species accumulation. Ruscogenin (RGN), a steroidal sapogenin of Radix Ophiopogon japonicus, has significant anti-thrombotic/anti-inflammatory effects.

Objective:

The aim of this study was to assess the protective role of RGN against DON-induced oxidative stress, which occurs through the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway and is regulated by phosphoinositide 3-kinases/protein kinase B (PI3K/AKT).

Methods:

The effects were examined using the HepG2 cell line. RGN and DON were suspended in serum-free medium. Cells were seeded onto plates, and then RGN, DON, or both were added over 24 h in triplicates for each group.

Results:

RGN conferred protection against DON-exhibited cytotoxicity against HepG2 cells. RGN pretreatment downregulated the expression of DON-induced TNF-α and COX-2 and the formation of reactive oxygen species in a dose-dependent manner. RGN upregulated the expression of Nrf2 and its antioxidant proteins as well as mRNA levels of HO-1/NQO-1/HO-1/Nrf2. Similarly, treatment with DON + RGN resulted in upregulation of the pI3K/pAKT signaling pathway in a dose-dependent manner. Finally, RGN was also found to inhibit the DON-induced apoptosis by upregulating the levels of cleaved proteins and downregulating the expression of Bcl2.

Conclusion:

The study demonstrates that RGN suppresses hepatic cell injury induced by oxidative stress through Nrf2 via activation of the pI3K/AKT signaling pathway.

Statin Use and COVID-19 Infectivity and Severity in South Korea: Two Population-Based Nationwide Cohort Studies

Background

Basic studies suggest that statins as add-on therapy may benefit patients with COVID-19; however, real-world evidence of such a beneficial association is lacking.

Objective

We investigated differences in SARS-CoV-2 test positivity and clinical outcomes of COVID-19 (composite endpoint: admission to intensive care unit, invasive ventilation, or death) between statin users and nonusers.

Methods

Two independent population-based cohorts were analyzed, and we investigated the differences in SARS-CoV-2 test positivity and severe clinical outcomes of COVID-19, such as admission to the intensive care unit, invasive ventilation, or death, between statin users and nonusers. One group comprised an unmatched cohort of 214,207 patients who underwent SARS-CoV-2 testing from the Global Research Collaboration Project (GRCP)-COVID cohort, and the other group comprised an unmatched cohort of 74,866 patients who underwent SARS-CoV-2 testing from the National Health Insurance Service (NHIS)-COVID cohort.

Results

The GRCP-COVID cohort with propensity score matching had 29,701 statin users and 29,701 matched nonusers. The SARS-CoV-2 test positivity rate was not associated with statin use (statin users, 2.82% [837/29,701]; nonusers, 2.65% [787/29,701]; adjusted relative risk [aRR] 0.97; 95% CI 0.88-1.07). Among patients with confirmed COVID-19 in the GRCP-COVID cohort, 804 were statin users and 1573 were matched nonusers. Statin users were associated with a decreased likelihood of severe clinical outcomes (statin users, 3.98% [32/804]; nonusers, 5.40% [85/1573]; aRR 0.62; 95% CI 0.41-0.91) and length of hospital stay (statin users, 23.8 days; nonusers, 26.3 days; adjusted mean difference –2.87; 95% CI –5.68 to –0.93) than nonusers. The results of the NHIS-COVID cohort were similar to the primary results of the GRCP-COVID cohort.

Conclusions

Our findings indicate that prior statin use is related to a decreased risk of worsening clinical outcomes of COVID-19 and length of hospital stay but not to that of SARS-CoV-2 infection.

Impact of IL-1β and the IL-1R antagonist on relapse risk and survival in AML patients undergoing immunotherapy for remission maintenance

Interleukin-1 beta (IL-1β), a pro-inflammatory cytokine, has been ascribed a role in the expansion of myeloid progenitors in acute myeloid leukemia (AML) and in promoting myeloid cell-induced suppression of lymphocyte-mediated immunity against malignant cells. This study aimed at defining the potential impact of IL-1β in the post-remission phase of AML patients receiving immunotherapy for relapse prevention in an international phase IV trial of 84 patients (ClinicalTrials.gov; NCT01347996). Consecutive serum samples were collected from AML patients in first complete remission (CR) who received cycles of relapse-preventive immunotherapy with histamine dihydrochloride (HDC) and low-dose interleukin-2 (IL-2). Low IL-1β serum levels before and after the first HDC/IL-2 treatment cycle favorably prognosticated leukemia-free survival and overall survival. Serum levels of IL-1β were significantly reduced in patients receiving HDC/IL-2. HDC also reduced the formation of IL-1β from activated human PBMCs in vitro. Additionally, high serum levels of the IL-1 receptor antagonist IL-1RA were associated with favorable outcome, and AML patients with low IL-1β along with high IL-1RA levels were strikingly protected against leukemic relapse. Our results suggest that strategies to target IL-1β might impact on relapse risk and survival in AML.

Myeloid HMG-CoA (3-Hydroxy-3-Methylglutaryl-Coenzyme A) Reductase Determines Atherosclerosis by Modulating Migration of Macrophages

Objective- Inhibition of HMGCR (3-hydroxy-3-methylglutaryl-coenzyme A reductase) is atheroprotective primarily by decreasing plasma LDL (low-density lipoprotein)-cholesterol. However, it is unknown whether inhibition of HMGCR in myeloid cells contributes to this atheroprotection. We sought to determine the role of myeloid HMGCR in the development of atherosclerosis. Approach and Results- We generated mice with genetically reduced Hmgcr in myeloid cells ( Hmgcr ^{m- /m-}) using LysM (Cre) and compared various functions of their macrophages to those of Hmgcr ^fl/fl control mice. We further compared the extent of atherosclerosis in Hmgcr ^{m-/ m-} and Hmgcr ^fl/fl mice in the absence of Ldlr (LDL receptor). Hmgcr ^{m-/ m-} macrophages and granulocytes had significantly lower Hmgcr mRNA expression and cholesterol biosynthesis than Hmgcr ^fl/fl cells. In vitro, Hmgcr ^{m-/ m-} monocytes/macrophages had reduced ability to migrate, proliferate, and survive compared with Hmgcr ^fl/fl monocytes/macrophages. However, there was no difference in ability to adhere, phagocytose, store lipids, or polarize to M1 macrophages between the 2 types of macrophages. The amounts of plasma membrane-associated small GTPase proteins, such as RhoA (RAS homolog family member A), were increased in Hmgcr ^{m-/ m-} macrophages. In the setting of Ldlr deficiency, Hmgcr ^{m-/ m-} mice developed significantly smaller atherosclerotic lesions than Hmgcr ^fl/fl mice. However, there were no differences between the 2 types of mice either in plasma lipoprotein profiles or in the numbers of proliferating or apoptotic cells in the lesions in vivo. The in vivo migration of Hmgcr ^{m-/ m-} macrophages to the lesions was reduced compared with Hmgcr ^fl/fl macrophages. Conclusions- Genetic reduction of HMGCR in myeloid cells may exert atheroprotective effects primarily by decreasing the migratory activity of monocytes/macrophages to the lesions.

Expression of Histidine Decarboxylase and Its Roles in Inflammation

Histamine is a well-known mediator of inflammation that is released from mast cells and basophils. To date, many studies using histamine receptor antagonists have shown that histamine acts through four types of receptors: H1, H2, H3, and H4. Thus, histamine plays more roles in various diseases than had been predicted. However, our knowledge about histamine-producing cells and the molecular mechanisms underlying histamine production at inflammatory sites is still incomplete. The histamine producing enzyme, histidine decarboxylase (HDC), is commonly induced at inflammatory sites during the late and chronic phases of both allergic and non-allergic inflammation. Thus, histamine levels in tissues are maintained at effective concentrations for hours, enabling the regulation of various functions through the production of cytokines/chemokines/growth factors. Understanding the regulation of histamine production will allow the development of a new strategy of using histamine antagonists to treat inflammatory diseases.

Statins: Old drugs as new therapy for liver diseases?

In addition to lowering cholesterol levels, statins have pleiotropic effects, particularly anti-inflammatory, antiangiogenic, and antifibrotic, that may be beneficial in some chronic inflammatory conditions. Statins have only recently been investigated as a potential treatment option in chronic liver diseases because of concerns related to their safety in patients with impaired liver function. A number of experimental studies in animal models of liver diseases have shown that statins decrease hepatic inflammation, fibrogenesis and portal pressure. In addition, retrospective cohort studies in large populations of patients with cirrhosis and pre-cirrhotic conditions have shown that treatment with statins, with the purpose of decreasing high cholesterol levels, was associated with a reduced risk of disease progression, hepatic decompensation, hepatocellular carcinoma development, and death. These beneficial effects persisted after adjustment for disease severity and other potential confounders. Finally, a few randomised controlled trials have shown that treatment with simvastatin decreases portal pressure (two studies) and mortality (one study). Statin treatment was generally well tolerated but a few patients developed severe side effects, particularly rhabdomyolysis. Despite these promising beneficial effects, further randomised controlled trials in large series of patients with hard clinical endpoints should be performed before statins can be recommended for use in clinical practice.

Statins in the treatment of COPD and asthma-where do we stand?

Asthma and chronic obstructive pulmonary disease (COPD) are the two most prevalent obstructive lung diseases that account for tremendous morbidity and mortality throughout the world. These diseases have strong inflammatory components, with multiple prior studies showing elevated levels of various inflammatory markers and cells in those with COPD and asthma. Therefore, efforts to target inflammation in management of these diseases are of great interest. Statins, which define a class of drugs that are HMG-CoA inhibitors, are used to decrease cholesterol levels and have also been described to have many pleotropic effects that include anti-inflammatory and anti-oxidative properties. These properties have led to multiple studies looking at the potential use of statins in decreasing inflammation in many diseases, including COPD and asthma. This review aims to address the current evidence behind the potential use of statins in the treatment of asthma and COPD.

Statins: immunomodulators for autoimmune rheumatic disease?

Inhibitors of 3-hydroxy-3-methylgluttaryl coenzyme A (HMG-CoA) reductase, or statins, are used extensively to reduced elevated lipid levels and reduce cardiovascular risk. However, accumulated evidence suggests that stains not only act by lowering cholesterol levels, but also exert pleiotropic effects on many essential cellular functions including cell proliferation, differentiation, and survival and participate in the regulation of cell shape and motility. Thus cardiovascular benefit is provided by lowering raised cholesterol levels and by modulation of the inflammatory component of this disease. Such an anti-inflammatory effect may also benefit patients with autoimmune rheumatic disease. This overview assesses the evidence for using statins in patients with rheumatoid arthritis and systemic lupus erythematosus (SLE).

The role of poly(ADP-ribose) polymerase-1 inhibitor in carrageenan-induced lung inflammation in mice

Increasing indication is unveiling a role for poly(ADP-ribose) polymerase (PARP)-1 in the regulation of inflammatory/immune responses. The aim of the present study was to determine the potential anti-inflammatory effects of PARP-1 inhibitor 5-aminoisoquinolinone (5-AIQ) to explore the role of PARP-1 inhibitor in a mouse model of carrageenan-induced lung inflammation. A single dose of 5-AIQ (1.5mg/kg) was administered intraperitoneally (i.p.) 1h before λ-carrageenan (Cg) administration. We assessed the effects of 5-AIQ treatment on CD25(+), GITR(+), CD25(+)GITR(+), IL-17(+) and Foxp3(+) cells which were investigated using flowcytometry in pleural exudates and heparinized blood. We also evaluated mRNA expressions of IL-6, TNF-α, IL-1β, IL-10, CD11a, l-selectin (CD62L), ICAM-1, MCP-1, iNOS and COX-2 in the lung tissue. We further examined the effects of 5-AIQ on the key mediators of inflammation, namely COX-2, STAT-3, NF-kB p65, PARP-1, IkB-α and IL-4 protein expression in the lung tissue using western blotting. The results illustrated that the numbers of T cell subsets, IL-17(+) cytokine levels were markedly increased and Foxp3(+) production decreased in the Cg group. Furthermore, Cg-induced up-regulation of adhesion molecules, pro-inflammatory mediators and chemokine expressions. Western blot analysis revealed an increased protein expressions of COX-2, STAT-3 NF-kB p65 and PARP-1 and decreased IkB-α and IL-4 in the Cg group. PARP-1 inhibitor via 5-AIQ treatment reverses the action significantly of all the previously mentioned effects. Moreover, histological examinations revealed anti-inflammatory effects of 5-AIQ, whereas Cg-group aggravated Cg-induced inflammation. Present findings demonstrate the potent anti-inflammatory action of the PARP-1 inhibitor in acute lung injury induced by carrageenan.

Anti-LFA-1 antibodies enhance metastasis of ocular lymphoma to the brain and contralateral eye

Previously we demonstrated that intraperitoneal (IP) inoculation of Rev-2-T-6 mouse lymphoma into syngeneic Balb/c hosts resulted in brain metastasis, migration along the optic nerve sheath, and ocular infiltration. In a second model: intravitreal inoculation of Rev-2-T-6 cells, the developing lymphoma was largely confined within the eye, seldom breaching the retinal pigment epithelium to reside in the choroid and sclera. There was no retrograde infiltration into the brain. Here, we describe a third, complementary model, whereby intravitreal inoculation of Rev-2-T-6 cells into Balb/c mice, followed by repeated IP inoculations of anti-LFA-1/CD11a monoclonal antibodies, results in extensive infiltration of the choroid, sclera, conjunctiva, eyelids and orbit. Furthermore, the lymphoma cells metastasize along the optic nerve sheath into the brain, and through the contralateral optic nerve tract into the contralateral eye. There is no systemic involvement of the lymphoma. Furthermore, anti-LFA-1 treatment results in elevated levels of serum anti-Rev-2-T-6 antibodies. Inoculation of Rev-2-T-6 cells into the vitreous of severe combined immune deficient mice demonstrates a course of clinical signs and histopathological findings similar to those in immune-competent mice treated with anti-LFA-1 antibodies, including invasion of the contralateral eye. Taken together, these findings suggest that confinement of Rev-2-T-6 lymphoma cells to the eye depends on active immune surveillance using a population of effector cells expressing the cell surface integrin LFA-1. Impairing this protection enhances tumor aggressiveness within the eye, and the likelihood of early retrograde lymphoma metastasis into the brain and the contralateral eye.

A novel flow cytometric high throughput assay for a systematic study on molecular mechanisms underlying T cell receptor-mediated integrin activation

Lymphocyte function-associated antigen 1 (LFA-1), a member of β2-integrin family, exerts multiple roles in host T cell immunity and has been identified as a useful drug-development target for inflammatory and autoimmune diseases. Applying the findings that primary resting T cells absorb nanometric membrane vesicles derived from antigen presenting cells (APC) via dual receptor/ligand interactions of T cell receptor (TCR) with cognate peptide-major histocompatibility complex (MHC) complex (pMHC) and LFA-1 with its ligand, intercellular adhesion molecule-1 (ICAM-1), and that signaling cascades triggered by TCR/pMHC interaction take a part in the vesicle-absorption, we established a cell-based high throughput assay for systematic investigation, via isolation of small molecules modulating the level of vesicle-absorption, of molecular mechanisms underlying the T cell absorption of APC-derived vesicles, i.e., structural basis of TCR/pMHC and LFA-1/ICAM-1 interactions and TCR-mediated LFA-1 activation. As primary T cells along with physiological ligands expressed in biological membrane are used and also individual cells in assay samples are analyzed by flow cytometry, results obtained using the assay system hold superior physiological and therapeutic relevance as well as statistical precision.

Potential skin antiinflammatory effects of 4-methylthiobutylisothiocyanate (MTBI) isolated from rocket (Eruca sativa) seeds

Isothiocyanates (ITCs), which are organosulfur compounds present in cruciferous vegetables, have anticarcinogenic, antiinflammatory, and antiproliferative activities. These biological activities, and the knowledge that rocket seed (Eruca sativa) extract is used in skin disorders in traditional Middle Eastern medicine, led to the isolation and assessment of 4-methylthiobutylisothiocyanate (MTBI), the major ITC in rocket seeds, for its potential in the prevention of inflammatory skin diseases, such as psoriasis. MTBI was found to depress the growth of activated keratinocytes and to arrest the activated THP-1 monocytes in the G2 stage. Both MTBI and its oxidized derivative sulforaphane (SFN), which was found in the rocket seed at a low concentration, downregulated the expression of the proinflammatory genes, tumor necrosis factor (TNF)-alpha and interleukin (IL)-12/23 p40, as well as that of intercellular adhesion molecule-1, in activated THP-1 cells. These results demonstrate that MTBI may deter the inflammation process, as has been reported for SFN. Furthermore, pretreatment with MTBI hindered the induction of the inflammatory state in the THP-1 cells, as shown by the inhibition of cytokine mRNA expression of IL-1beta, IL-12/23 p40, and TNF-alpha. Overall, our results imply that MTBI may represent a new family of natural compounds possessing significant skin inflammation-preventive activities.

Induction of ICAM-1 and VCAM-1 on the mouse lingual lymphatic endothelium with TNF-alpha

This study investigated the TNF-α-induced ICAM-1 and VCAM-1 expression on mouse lingual lymphatic vessels. All podoplanin-positive lymphatic vessels expressed PECAM-1. In the lamina propria mucosae of TNF-α-treated tongue, almost all initial lymphatics expressed ICAM-1. There were initial lymphatics with the VCAM-1 expression and also the vessels without the expression. In the tunica muscularis of TNF-α-treated tongue, collecting lymphatic vessels expressed ICAM-1, but rarely expressed VCAM-1 whereas blood vessels simultaneously expressed ICAM-1 and VCAM-1. The ICAM-1-positive rate increased with TNF-α to 75% from 10% on initial lymphatics, and to 40% from 0% on collecting lymphatic vessels while it increased to 90% from 45% on blood vessels. The VCAM-1-positive rate increased with TNF-α to 30% from 0% on initial lymphatics, and to 5% from 0% on collecting lymphatic vessels while it increased to 75% from 5% on blood vessels. These findings suggest that the lingual lymphatic endothelium has the ability to express ICAM-1, and VCAM-1 to a lesser extent than the ICAM-1 induction with TNF-α, and that the ICAM-1 and VCAM-1 induction predominantly occurs in the initial lymphatics compared with collecting lymphatic vessels.

Cyclosporin A inhibits CD11a/CD18 adhesion molecules due to inhibition of TNFalpha and IL-1 beta levels in the mouse model of pleurisy induced by carrageenan

The mouse model of pleurisy induced by carrageenan is characterized by a significant enhancement of cell migration due to neutrophils 4 h after pleurisy induction. Forty-eight hours after pleurisy induction, a significant increase in cell migration due to mononuclear cells occurs. Recently, studies in our laboratory have demonstrated that cyclosporine A (CsA) inhibits leukocyte migration in the pleural cavity and lungs in the mouse model of pleurisy induced by carrageenan. In the present work we evaluated whether CsA was able to downregulate CD11a/CD18 adhesion molecule in the lungs, as well as TNFalpha and IL-1 beta levels in the fluid leakage of the pleural cavity in this model. Our results showed that CsA significantly decreased CD11a/CD18 in the lungs, as well as TNFalpha and IL-1 beta levels in the fluid leakage of the pleural cavity 4 h and 48 h after pleurisy induction. It is our hypothesis that the inhibitory effect elicited by CsA upon these adhesion molecules may be also be attributed to the downregulation of TNFalpha and IL-1 beta cytokines.

Leukocyte adhesion molecule and chemokine production through lipoteichoic acid recognition by toll-like receptor 2 in cultured human lymphatic endothelium

We have recently reported that the human lymphatic endothelium has toll-like receptor 4 (TLR4)-mediated lipopolysaccharide recognition mechanisms that induce the expression of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1). Although ligand engagement with TLR2 enables activation of the MyD88-dependent pathway similarly to TLR4, whether TLR2 ligands such as lipoteichoic acid (LTA) trigger the activation of lymphatic endothelium remains unclear. This study has been designed to investigate the expression dynamics of LTA-induced leukocyte adhesion molecules and chemokines in cultured human lymphatic endothelium (LEC). Reverse transcription/polymerase chain reaction (RT-PCR) and real-time quantitative PCR analyses have shown that LEC usually expresses TLR2 and increases TLR2 gene expression on LTA treatment. Indeed, LTA-treated LEC increases the expression of E-selectin, ICAM-1, and VCAM-1 but does not alter the gene expression of ICAM-2, ICAM-3, junctional adhesion molecule-1 (JAM-1), JAM-3, or platelet endothelial cell adhesion molecule-1 (PECAM-1). The expression of LTA-induced E-selectin, ICAM-1, and VCAM-1 in LEC is suppressed by anti-TLR2 but not by anti-TLR4 and is also suppressed by TLR2-specific short interfering RNA (siRNA) but not by siRNA for TLR4. The expression of CCL2, CCL5, and CCL20 (Cys-Cys motif chemokines) and of CXCL1, CXCL3, CXCL5, CXCL6, and CXCL8 (Cys-X-Cys motif chemokines) was induced in LEC with LTA. These data suggest that the human lymphatic endothelial phenotype has TLR2-mediated LTA-recognition mechanisms, resulting in increased expression of inflammatory leukocyte adhesion molecules and phagocyte-attractive chemokines. The human lymphatic endothelium may thus function to collect leukocytes from tissues into lymphatic vessels by means of immunologically functional molecules.

Intercellular adhesion molecule-1 (ICAM-1) expression is necessary for monocyte adhesion to the placental bed endothelium and is increased in type 1 diabetic human pregnancy

BACKGROUND

That adhesion molecule expression is upregulated in endothelial cells of the placental bed in pregnancies complicated by type 1 diabetes mellitus, and that this is associated with increased adherence of peripheral blood monocytes, which can be reversed by reduction in activity or expression of relevant adhesion molecules. Specific aims were to compare the adherence of monocytes from normal pregnancies to decidual endothelial cells from both normal and diabetic pregnancies, and to examine the involvement of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) in regulation of such adhesion.

METHODS

We examined adhesion of peripheral blood monocytes (isolated by density gradient centrifugation) of normal third trimester pregnant women, to cultured endothelial cells (isolated from decidual biopsies collected at elective caesarean section) from both normal women and those with type 1 diabetes. Adhesion molecule expression was determined by flow cytometry. The role of ICAM-1 was further investigated by monoclonal antibody-blocking experiments and gene-silencing methodology.

RESULTS

There was a significant increase in monocyte adhesion to decidual endothelial cells from diabetic pregnancies, associated with increased endothelial cell expression of ICAM-1, but not VCAM-1. ICAM-1 expression in normal decidual endothelial cells was stimulated by pro-atherogenic and pro-inflammatory stimuli. Following ICAM-1 antibody blockade, monocyte adhesion was decreased by > 70%. ICAM-1 silencing by small interfering RNAs also inhibited monocyte adhesion and ICAM-1 expression.

CONCLUSIONS

These findings implicate upregulation of ICAM-1 in decidual endothelial cells in the development of placental bed vascular pathology in diabetic pregnancy.

[Inducible histamine protects mice from hepatitis through H2-receptor stimulation]

Histamine is well known for its roles in allergic diseases and anaphylaxis through H(1)-receptor stimulation. The H(1)-receptor stimulation by histamine results in an increase in vascular permeability, vasodilatation, and stimulation of nerve terminals in primary sensory neurons, thereby accelerating the inflammatory responses. On the other hand, histamine has been demonstrated to be involved in the regulation of innate and acquired immune responses through H(2)-receptors. In a previous study with human peripheral blood mononuclear cells, we observed that histamine exerts various regulatory effects on monocyte/macrophage function. In this review, we discuss how inducible histamine protects mice from lethal hepatitis, induced by heat-killed P.acnes (1 mg, i.v.) followed by challenge with a low dose of lipopolysaccharide (1 microg), by reducing the excessive cytokine response in the liver. In addition, from in vivo studies with histidine decarboxylase knockout and H(1)-, H(2)-receptor knockout mice, the protective effect of histamine against fulminant hepatitis is shown to be elicited through H(2)-receptor stimulation.

Human immunodeficiency virus infection and macrophage cholesterol metabolism

Macrophages play a central role in the pathogenesis of atherosclerosis and are also a host for a number of viruses, most importantly, HIV. Many viruses, including HIV, require cholesterol for their replication and as a structural element. Cholesterol also plays a pivotal role in innate antiviral immune responses. Although impairing innate immune response by increasing cell cholesterol content may be a deliberate strategy used by a pathogen to improve its infectivity, enhancing the risk of atherosclerosis is likely a byproduct. Consistent association between HIV infection and elevated risk of atherosclerosis suggested a connection between virus-induced changes in cholesterol metabolism and atherogenesis, but the mechanisms of such connection have not been identified. We describe in this review various mechanisms enabling viruses to exploit macrophage pathways of cholesterol metabolism, thus diverting cholesterol for a purpose of increasing viral replication and/or for altering innate immune responses. To alter the cellular cholesterol content, viruses "hijack" the pathways responsible for maintaining intracellular cholesterol metabolism. The damage to these pathways by viral infection may result in the inability of macrophages to control cholesterol accumulation and may lead to formation of foam cells, a characteristic feature of atherosclerosis. Further elucidation of the mechanisms connecting viral infection and macrophage cholesterol metabolism may be fruitful for developing approaches to treatment of atherosclerosis and viral diseases.

Upregulation of ICAM-1 expression in bronchial epithelial cells by airway secretions in bronchiectasis

The airway epithelium participates in chronic airway inflammation by expressing adhesion molecules that mediate the transmigration of neutrophils into the inflamed airways. We hypothesize that, in patients with bronchiectasis, cytokines in their bronchial secretions enhance the expression of intercellular cell adhesion molecule (ICAM-1) in the bronchial epithelium and thus contribute to sustained recruitment of neutrophils into the inflamed airways. In the present study, we investigated the effect of bronchial secretions on the regulation of ICAM-1 in bronchial epithelial cells, and its modulation by pharmacologic agents. The expression of ICAM-1 mRNA and protein in human bronchial epithelial cells upon exposure to sputum sol from subjects with bronchiectasis were evaluated by reverse transcription-polymerase chain reaction (RT-PCR) and ELISA, respectively. Modulating effects of dexamethasone, ibuprofen, MK-663 or triptolide on ICAM-1 regulation were investigated in vitro. We demonstrated that changes in ICAM-1 expression correlated with levels of TNF-alpha in the sputum sol, and treatment of sol samples with TNF-alpha antibodies attenuated both the increase in ICAM-1 mRNA and protein. The role of TNF-alpha was further demonstrated when TNF-alpha elicited dose dependent increase in ICAM-1 expression. The sputum effect could also be suppressed dose-dependently by pre-incubation of bronchial epithelial cells with dexamethasone, ibuprofen, MK-663 or triptolide. Evidence is thus provided for the upregulation of bronchial epithelial ICAM-1 expression by airway secretions in bronchiectasis and a specific role for TNF-alpha in the secretions. The success of drug attenuation of this upregulation provides insight into possible therapeutic paradigms in the management of the disease.

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.

Relation between common polymorphisms in genes related to inflammatory response and colorectal cancer

AIM: To investigate the association between common single nucleotide polymorphisms (SNPs) in inflammatory response-related genes such as interleukin (IL)-6, IL-8, tumor necrosis factor α (TNFα), peroxisome proliferators-activated receptor γ (PPARγ), intercellular adhesion molecule-1 (ICAM-1) and the risk of colorectal cancer (CRC) in a group of Greek patients.

METHODS: The study group consisted of 222 CRC patients and 200 healthy controls. Genotyping was performed using allele-specific PCR of PRC-RFLP and the results were confirmed by sequencing. We studied the association of SNPs in the IL-6 (-174G > C), IL-8 (-251T > A), TNFα (-308G > A), ICAM-1 (R241G and K469E), and PPARγ (Pro12Ala) genes and the risk of CRC.

RESULTS: The IL-6 -174G, R241 and K469 alleles of ICAM-1 were associated with increased risk of CRC (OR = 1.77, 95% CI: 1.34-2.34; OR = 1.83, 95% CI: 1.23-2.72; and OR = 1.35, 95% CI: 1.03-1.77 respectively). The IL-8 and TNFα polymorphisms had no effect. Whereas the PPARγ Pro12 genotype was associated with increased risk of disease (OR = 1.78, 95% CI: 1.25-2.49).

CONCLUSION: The association between common SNPs in immunologic response-related genes and CRC is reported in the present study. Apart from shedding light on the mechanisms of malignancy initiation and progression, SNPs may improve appropriate screening for sub-populations at risk.

Potential therapeutic role for statins in respiratory disease

Statins reduce cholesterol levels by inhibiting 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase and have an established role in the treatment of atherosclerotic disease. Recent research has identified anti-inflammatory properties of statins. Statins appear to reduce the stability of lipid raft formation with subsequent effects on immune activation and regulation, and also prevent the prenylation of signalling molecules with subsequent downregulation of gene expression. Both these effects result in reduced cytokine, chemokine, and adhesion molecule expression, with effects on cell apoptosis or proliferation. This review considers the evidence for the anti-inflammatory properties of statins in the lung, and how these effects are being applied to research into the role of statins as a novel treatment of respiratory diseases.

Intercellular adhesion molecule-1 expression in human endometrium: implications for long term progestin only contraception

BACKGROUND

Neutrophils infiltrate the endometrium pre-menstrually and after long-term progestin only-contraceptive (LTPOC) treatment. Trafficking of neutrophils involves endothelial cell-expressed intercellular adhesion molecule (ICAM-1). Previous studies observed that ICAM-1 was immunolocalized to the endothelium of endometrial specimens across the menstrual cycle, but disagreed as to whether extra-endothelial cell types express ICAM-1 and whether ICAM-1 expression varies across the menstrual cycle.

METHODS

Endometrial biopsies were obtained from women across the menstrual cycle and from those on LTPOC treatment (either Mirena or Norplant). The biopsies were formalin-fixed and paraffin-embedded with subsequent immunohistochemical staining for ICAM-1.

RESULTS

The current study found prominent ICAM-1 staining in the endometrial endothelium that was of equivalent intensity in different blood vessel types irrespective of the steroidal or inflammatory endometrial milieu across the menstrual cycle and during LTPOC therapy. Unlike the endothelial cells, the glands were negative and the stromal cells were weakly positive for ICAM immunostaining.

CONCLUSION

The results of the current study suggest that altered expression of ICAM-1 by endothelial cells does not account for the influx of neutrophils into the premenstrual and LTPOC-derived endometrium. Such neutrophil infiltration may depend on altered expression of neutrophil chemoattractants.

Inducible histamine protects mice from P. acnes-primed and LPS-induced hepatitis through H2-receptor stimulation

BACKGROUND & AIMS

Inducible histamine and histamine H2-receptors have been suggested to be involved in innate immune response.

METHODS

We examined a functional role of inducible histamine in the protection against hepatic injury and lethality in Propionibacterium acnes -primed and lipopolysaccharide-induced hepatitis, using histidine decarboxylase knockout and H2-receptor knockout mice.

RESULTS

Lipopolysaccharide challenge after Propionibacterium acnes priming increased histidine decarboxylase activity in the liver of wild-type mice, associated with a marked elevation of histamine turnover. Histidine decarboxylase-like immunoreactivity was observed in CD68-positive Kupffer cells/macrophages. Treatment of wild-type mice with famotidine or ranitidine but not d -chlorpheniramine augmented hepatic injury and inhibited the survival rate significantly. The same dose of Propionibacterium acnes and lipopolysaccharide induced severe hepatitis and high lethality in histidine decarboxylase knockout and H2-receptor knockout mice; the former were rescued by the subcutaneous injection of histamine. Immunohistochemical study supported the protective role of histamine against the apoptosis of hepatocytes. Histamine suppressed the expression of IL-18 and tumor necrosis factor alpha in the liver, leading to the reduced plasma levels of cytokines including IL-18, TNF-alpha, IL-12, IFN-gamma, and IL-6.

CONCLUSIONS

These findings as a whole indicated that endogenously produced histamine in Kupffer cells/macrophages plays a very important role in preventing excessive innate immune response in endotoxin-induced fulminant hepatitis through the stimulation of H2-receptors.

Unique regulation profile of prostaglandin e1 on adhesion molecule expression and cytokine production in human peripheral blood mononuclear cells

In the present study, we examined the effects of prostaglandin E1 (PGE1) on the expression of intercellular adhesion molecule (ICAM)-1, B7.1, B7.2, CD40, and CD40 ligand (CD40L) on peripheral blood mononuclear cells (PBMC) using fluorescence-activated cell sorting analysis as well as its effects on cytokine production using enzyme-linked immunosorbent assay. Whereas no inhibitor of spontaneous expression of adhesion molecules was reported, we found that PGE1 inhibited spontaneous ICAM-1, B7.2, and CD40 expression on monocytes in a concentration-dependent manner but had no effect on the expression of B7.1 and CD40L. Although interleukin (IL)-18 induced the expression of ICAM-1, B7.2, CD40, and CD40L, PGE1 prevented IL-18-induced expression of ICAM-1, B7.2, and CD40. We examined the involvement of five subtypes of PGE1 receptors (IP, EP1, EP2, EP3, and EP4) in the effect of PGE1 on the expression of these adhesion molecules using subtype-specific agonists. Among EP receptor agonists, EP2 and EP4 receptor agonists inhibited IL-18-elicited ICAM-1, B7.2, and CD40 expression. ONO-1301 (IP receptor agonist) prevented the expression of ICAM-1, B7.2, and CD40 regardless of the presence of IL-18 with the same potency as PGE1. The effect of a combination of ONO-1301 and 11-deoxy (D)-PGE1 (EP2/EP4 receptor agonist) on ICAM-1, B7.2, and CD40 expression mimicked that of PGE1. Moreover, PGE1 inhibited the production of IL-12 and interferon-gamma in PBMC in the presence and absence of IL-18, whereas PGE1 induced IL-10 production. In conclusion, IP receptor and EP2/EP4 receptor play an important role in the action of PGE1 on the expression of adhesion molecules on monocytes and cytokine production.