Intracellular Adhesion Molecule-1 Expression Research Articles

The mechanism of the contribution of ICAM-1 to epithelial-mesenchymal transition (EMT) in bladder cancer.

Bladder cancer is one of the most prevalent cancers worldwide. Moreover, if not optimally treated, bladder cancer is a significant burden on healthcare systems due to multiple recurrences which often require more aggressive therapies. Therefore, targeted anti-cancer therapies, developed based on an in-depth understanding of specific proteins and molecular mechanisms, are promising in cancer treatment. Here, for the first time, we presented the new approaches indicating that intracellular adhesion molecule-1 (ICAM-1) may play a potential role in enhancing therapeutic effectiveness for bladder cancer. In the present study, we presented that ICAM-1 expression as well as its regulation in bladder cancer is strongly correlated with the high expression of N-cadherin. Importantly, the presence of N-cadherin and its regulator-TWIST-1 was abolished when ICAM-1 was silenced. We identified also that ICAM-1 is capable of regulating cellular migration, proliferation, and EMT progression in bladder cancer cells via the N-cadherin/SRC/AKT/GSK-3β/β-catenin signaling axis. Therefore, we propose ICAM-1 as a novel metastatic marker for EMT progression, which may also be used as a therapeutic target in bladder cancer.

Carbon Nanodots Inhibit Tumor Necrosis Factor-α-Induced Endothelial Inflammation through Scavenging Hydrogen Peroxide and Upregulating Antioxidant Gene Expression in EA.hy926 Endothelial Cells.

Carbon nanodots (CNDs) are a new type of nanomaterial with a size of less than 10 nanometers and excellent biocompatibility, widely used in fields such as biological imaging, transmission, diagnosis, and drug delivery. However, its potential and mechanism to mediate endothelial inflammation have yet to be explored. Here, we report that the uptake of CNDs by EA.hy926 endothelial cells is both time and dose dependent. The concentration of CNDs used in this experiment was found to not affect cell viability. TNF-α is a known biomarker of vascular inflammation. Cells treated with CNDs for 24 h significantly inhibited TNF-α (0.5 ng/mL)-induced expression of intracellular adhesion molecule 1 (ICAM-1) and interleukin 8 (IL-8). ICAM-1 and IL-8 are two key molecules responsible for the activation and the firm adhesion of monocytes to activated endothelial cells for the initiation of atherosclerosis. ROS, such as hydrogen peroxide, play an important role in TNF-α-induced inflammation. Interestingly, we found that CNDs effectively scavenged H2O2 in a dose-dependent manner. CNDs treatment also increased the activity of the antioxidant enzyme NQO1 in EA.hy926 endothelial cells indicating the antioxidant properties of CNDs. These results suggest that the anti-inflammatory effects of CNDs may be due to the direct H2O2 scavenging properties of CNDs and the indirect upregulation of antioxidant enzyme NQO1 activity in endothelial cells. In conclusion, CND can inhibit TNF-α-induced endothelial inflammation, possibly due to its direct scavenging of H2O2 and the indirect upregulation of antioxidant enzyme NQO1 activity in endothelial cells.

Annotation of CD8+ T-cell function via ICAM-1 imaging identifies FAK inhibition as an adjuvant to augment the antitumor immunity of radiotherapy.

Background: Radiotherapy (RT) may trigger systemic antitumor immunity, manifesting as regression of non-irradiated lesions (abscopal effect). Intracellular adhesion molecule-1 (ICAM-1) is a key molecule involved in the abscopal effect of RT. However, the specific function of ICAM-1 in CD8+ T cells during antitumor immune responses remains unclear. Herein, we investigated whether noninvasive imaging of ICAM-1 can be used to annotate CD8+ T-cell function, thereby better selecting combinational therapy to enhance the antitumor immunity induced by RT. Methods: Using knockout mouse models, we investigated the role of ICAM-1 expressed on CD8+ T cells in the antitumor immunity of RT and conducted drug screening guided by ICAM-1-targeted noninvasive imaging. Results: The systemic antitumor effect of RT relies on the expression of ICAM-1 on CD8+ T cells. ICAM-1 expression is essential for CD8+ T-cell activation, proliferation, and effector function. Noninvasive annotation of the proliferation and effector function of CD8+ T cells by ICAM-1-targeted imaging identified VS-6063, a focal adhesion kinase inhibitor, as a new adjuvant to augment systemic antitumor immunity of RT in an immunologically "cold" tumor model. Mechanistically, VS-6063 overcomes the physical barriers in tumors and promotes the migration and infiltration of CD8+ T cells primed by RT into distant tumors. Conclusion: Our findings highlight that molecular imaging of ICAM-1 levels provides a dynamic readout of the proliferation and effector function of tumor-infiltrating CD8+ T cells, which facilitates the high-throughput exploitation of new combinational drugs to maximize the systemic antitumor effect of RT.

LncRNA PSMB8-AS1 Instigates Vascular Inflammation to Aggravate Atherosclerosis.

Increasing evidence suggests that long noncoding RNAs play significant roles in vascular biology and disease development. One such long noncoding RNA, PSMB8-AS1, has been implicated in the development of tumors. Nevertheless, the precise role of PSMB8-AS1 in cardiovascular diseases, particularly atherosclerosis, has not been thoroughly elucidated. Thus, the primary aim of this investigation is to assess the influence of PSMB8-AS1 on vascular inflammation and the initiation of atherosclerosis. We generated PSMB8-AS1 knockin and Apoe (Apolipoprotein E) knockout mice (Apoe-/-PSMB8-AS1KI) and global Apoe and proteasome subunit-β type-9 (Psmb9) double knockout mice (Apoe-/-Psmb9-/-). To explore the roles of PSMB8-AS1 and Psmb9 in atherosclerosis, we fed the mice with a Western diet for 12 weeks. Long noncoding RNA PSMB8-AS1 is significantly elevated in human atherosclerotic plaques. Strikingly, Apoe-/-PSMB8-AS1KI mice exhibited increased atherosclerosis development, plaque vulnerability, and vascular inflammation compared with Apoe-/- mice. Moreover, the levels of VCAM1 (vascular adhesion molecule 1) and ICAM1 (intracellular adhesion molecule 1) were significantly upregulated in atherosclerotic lesions and serum of Apoe-/-PSMB8-AS1KI mice. Consistently, in vitro gain- and loss-of-function studies demonstrated that PSMB8-AS1 induced monocyte/macrophage adhesion to endothelial cells and increased VCAM1 and ICAM1 levels in a PSMB9-dependent manner. Mechanistic studies revealed that PSMB8-AS1 induced PSMB9 transcription by recruiting the transcription factor NONO (non-POU domain-containing octamer-binding protein) and binding to the PSMB9 promoter. PSMB9 (proteasome subunit-β type-9) elevated VCAM1 and ICAM1 expression via the upregulation of ZEB1 (zinc finger E-box-binding homeobox 1). Psmb9 deficiency decreased atherosclerotic lesion size, plaque vulnerability, and vascular inflammation in Apoe-/- mice in vivo. Importantly, endothelial overexpression of PSMB8-AS1-increased atherosclerosis and vascular inflammation were attenuated by Psmb9 knockout. PSMB8-AS1 promotes vascular inflammation and atherosclerosis via the NONO/PSMB9/ZEB1 axis. Our findings support the development of new long noncoding RNA-based strategies to counteract atherosclerotic cardiovascular disease.

Knockdown of lncRNA PVT1 protects human trabecular meshwork cells against H2O2-induced injury via the regulation of the miR-29a-3p/VEGF/MMP-2 axis

PurposeHuman trabecular meshwork cell (HTMC) dysfunction results in imbalanced aqueous humor inflow and outflow, leading to an increase in intraocular pressure (IOP). Uncontrolled high IOP can promote the occurrence of glaucoma, an irreversible optic neuropathy. Here, we explored whether the long non-coding RNA plasmacytoma variant translocation 1 (lncRNA PVT1)/microRNA-29a-3p (miR-29a-3p) axis could ameliorate HTMC dysfunction under oxidative stress by modulating the expression of the proangiogenic factor vascular endothelial growth factor (VEGFA) and the profibrotic factor metalloproteinase-2 (MMP-2). MethodsHTMCs were cultured under H2O2-induced oxidative stress for 48 h. The expression of lncRNA PVT1, miR-29a-3p, VEGFA, MMP-2, intracellular adhesion molecule-1 (ICAM-1), and alpha-smooth muscle actin (α-SMA) was detected by reverse transcription quantitative real-time polymerase chain reaction, western blotting, and immunofluorescence. Interference experiments were conducted via the transfection of HTMCs with small interfering RNA (siRNA) targeting lncRNA PVT1 or miR-29a-3p mimics. A luciferase reporter assay was undertaken to identify the presence of a miR-29a-3p binding site in lncRNA PVT1. Flow cytometry and Transwell and Cell Counting Kit-8 assays were employed to evaluate HTMC functions under oxidative stress with different treatments. ResultsIn HTMCs, the expression of lncRNA PVT1 was induced by H2O2 treatment, whereas that of miR-29a-3p was inhibited. The levels of angiogenic factors (VEGFA, ICAM-1) and fibrosis-associated mediators (MMP-2, α-SMA) were upregulated in HTMCs under oxidative stress. The siRNA-mediated suppression of lncRNA PVT1 or the upregulation of miR-29a-3p significantly suppressed the expression of VEGFA, MMP-2, ICAM-1, and α-SMA. A luciferase reporter assay confirmed that lncRNA PVT1 directly targeted miR-29a-3p and acted as a miR-29a-3p sponge. The knockdown of lncRNA PVT1 restored the level of miR-29a-3p in H2O2-treated HTMCs, thereby inhibiting VEGFA and MMP-2, its target mRNAs. HTMC dysfunction, including increased apoptosis and decreased cell mobility and viability, could be effectively ameliorated by lncRNA PVT1 downregulation or miR-29a-3p overexpression under oxidative stress. ConclusionLncRNA PVT1 has potential as a therapeutic target for inhibiting VEGFA and MMP-2, thus protecting HTMCs, suppressing the progression of fibrosis, and, consequently, improving the outcome of glaucoma filtration surgery.

Fenofibrate Ameliorates Retinal Pigment Epithelium Injury Induced by Excessive Fat Through Upregulation of PI3K/AKT Signaling.

This study aimed to determine the effect and its mechanism of fenofibrate on retinal pigment epithelium (RPE) injury induced by excessive fat in vitro and in vivo. ARPE-19 cells were co-incubated with palmitic acid (PA) and fenofibric acid (the active form of fenofibrate after metabolism in vivo) and mice fed with high-fat diet (HFD) were supplemented with fenofibrate. The following methods were used: Western blot and immunofluorescent staining to determine expressions of reactive oxygen species (ROS)-associated factors and proinflammatory cytokines; electroretinogram (ERG) c-wave to evaluate RPE function; TUNEL staining to detect the apoptotic cell in RPE tissue. Additionally, ARPE19 cells were treated with PI3K/AKT inhibitor or agonist to investigate the mechanism of fenofibric acid inhibiting PA-induced RPE damage. We found that the application of PA inhibited RPE cell viability in a dose-dependent manner, and increased the levels of NAPDH oxidase 4 (NOX4), 3-nitrotyrosin (3-NT), intracellular adhesion molecule-1(ICAM1), tumor necrosis factor alpha (TNFα) and vascular endothelial growth factor (VEGF) at 400μM. The application of fenofibric acid resulted in the inhibition of NOX4, 3-NT, TNFα, ICAM1 and VEGF expression in ARPE-19 cells treated with PA. Moreover, wortmannin, as a selective inhibitor of PI3K/AKT pathway, abolished the effects of fenofibrate on the oxidative stress and inflammation in ARPE-19 cells. In addition, 740Y-P, a selective agonist of PI3K/AKT pathway, enhanced the protective action of fenofibrate. Meanwhile, in vivo dosing of fenofibrate ameliorated the downregulated amplitudes of ERG c-wave in HFD-fed mice and suppressed the HFD-induced oxidative injury and inflammatory response in RPE tissues. Our results suggested that fenofibrate ameliorated RPE cell damage induced by excessive fat in vitro and in vivo, in part, through activation of the PI3K/AKT signaling pathway.

THE ROLE OF ICAM1 IN TUMOR ASSOCIATED MACROPHAGES IN GLIOBLASTOMA TUMORIGENESIS

Abstract Glioblastoma (GBM) is a fatal brain cancer in adults with ineffective treatment methods. Cell adhesion molecules (CAMs) are proteins that are expressed on the surface of cells and enable them to interact with one another and the surrounding microenvironment. Intracellular adhesion molecule 1 (ICAM-1) is a cell adhesion molecule expressed by various cell types. Preliminary data showed that ICAM-1 is associated with poorer overall and progression free survival in patients and ICAM-1 expression levels increase in recurrent tumors. TAMs enhance GBM tumor growth. The aim of this study was to determine if ICAM-1 expression on TAMs contributes to GBM tumorigenesis, specifically within the hypoxic tumor microenvironment. We hypothesized that ICAM1 facilitates TAM migration, proliferation, cell adhesion and phagocytosis, thus enhancing tumor growth. We found that upon incubation of human and mouse primary macrophages in hypoxia, ICAM-1 expression levels increased and were further exasperated upon culturing with tumor cell-conditioned medium. The migration, cell adhesion and phagocytosis of ICAM-1 deficient macrophages was lower than wild type macrophages, and effects were further exasperated upon culturing with tumor conditioned media and incubation in hypoxia. Intracranial injection of tumor cells into ICAM-1 deficient and wild type mice revealed that ICAM1 deficient mice survived longer with lower overall tumor volume than wild type mice, with survival and volume differences being rescued upon ICAM1 bone marrow reconstitution. In conclusion, the expression of ICAM1 in TAMs likely promotes GBM tumorigenesis and hypoxia further enhances the expression of ICAM-1 in macrophages which is associated with more aggressive GBM.

Substance P Alleviates Retinal Pigment Epithelium Dysfunction Caused by High Glucose-Induced Stress.

When the retina is constantly affected by high glucose (HG) due to diabetes, the barrier function of the retinal pigment epithelium (RPE) is impaired, accompanied by unnecessary vascularization. This eventually leads to the development of diabetic retinopathy (DR). This study investigated the recovery effect of substance P (SP) on RPE injured by HG. RPE was treated with HG for 24 h, and HG-induced cellular injuries were confirmed. SP was added to the dysfunctional RPE. Compared to RPE in low glucose (LG) conditions, HG-damaged RPE had large, fibrotic cell shapes, and its cellular viability decreased. HG treatment reduced tight junction protein expression levels and caused oxidative stress by interrupting the antioxidant system; this was followed by inflammatory factor intracellular adhesion molecule-1 (ICAM-1), Monocyte chemotactic protein-1 (MCP-1), and angiogenesis factor vascular endothelial growth factor (VEGF) expression. SP treatment contributed to RPE recovery by enhancing cell viability, tight junction protein expression, and RPE function under HG conditions, possibly by activating the Akt signaling pathway. Importantly, SP treatment reduced ICAM-1, MCP-1, and VEGF expression. Collectively, SP activated survival signals to suppress oxidative stress and improve retinal barrier function in RPE, accompanied by immune suppression. This suggests the possible application of SP to diabetic retinal injuries.

Increase of Claudin-5, ICAM-1 and eNOS expressions in human brain endothelial cells by ammonium chloride

Abstract Objectives Lysosomal dysfunction could lead to a failure in the degradation process of waste materials, especially for the elimination of aggregated, misfolded and senescence proteins or organelles. Human brain endothelial cells (HBECs) are a part of the blood-brain barrier and any disruption of lysosomal functions could affect the cellular functions of the HBECs. Protein expression studies on the cells could give an insight to associate lysosomal dysfunction on HBECs homeostasis. The aim of this study was to measure the cellular changes via the expression of several proteins such as Claudin-5, which is a tight junction protein; intracellular adhesion molecule 1 (ICAM-1), an inflammatory marker and endothelial nitric oxide synthase (eNOS), which provides nitric oxide (NO) for vasodilation. These components are important in maintaining homeostasis as the imbalance could lead to endothelial impairment linked brain related disorders such as neurodegenerative disease. Methods HBECs were treated with 10 mM ammonium chloride, which is a lysosome inhibitor for 1 h. The protein lysates were collected and subjected for ICAM-1 and Claudin-5 measurement by capillary immunoassay instrument, while eNOS by ELISA. Results Claudin-5 and ICAM-1 expression significantly increased (p<0.05). The ELISA results showed eNOS increment (p<0.001) compared to control. Lysosome inhibitor could be associated with accumulation of organelles that can stimulates inflammation and initial cellular responses. Conclusions Inhibition of lysosome by the inhibitor increases protein expressions related with endothelial function.

In Vitro Antioxidant and Anti-inflammatory Effects of Erythroxylum cuneatum Leaf Extract on Oxidized Low-density Lipoprotein-stimulated Human Aortic Endothelial Cells

Background The oxidation of low-density lipoprotein (LDL) by reactive oxygen species (ROS) causes inflammation, which results in the expression of adhesion molecules and monocyte adhesion and migration. This eventually leads to the progression of atherosclerosis. Erythroxylum cuneatum (EC), locally known as “Chinta mula,” is used as traditional medicine in certain countries. However, the scientific evidence of its medicinal properties, particularly related to cardiovascular disease (CVD) is still limited. Objectives This study was designed to evaluate the antioxidant and anti-inflammatory properties of EC leaf extract in protecting against atherosclerosis in vitro. Materials and Methods Human aortic endothelial cells (HAoECs) induced by oxidized LDL (oxLDL) were treated with comparable concentrations (40 and 80 µg/ml) of EC ethanol and acetone leaf extracts. The antioxidant activities were determined by thiobarbituric acid reactive substances (TBARS), ROS, and nitric oxide (NO) production assays. The anti-inflammatory effects of EC leaf extract were evaluated using monocyte adhesion and migration assays and the expression of adhesion molecules, namely, intracellular adhesion molecule-1 (ICAM-1) and human vascular cell adhesion molecule-1 (VCAM-1). Results Both EC extracts possess antioxidant and anti-inflammatory activities against oxLDL-induced HAoECs, which were concentration-dependent. Acetone extract showed significant reduced TBARS levels and increased NO production compared to ethanol extract. It also caused a significant decrease in monocyte adhesion and expression of ICAM-1 as compared to ethanol extract. Conclusion These findings suggest that EC leaf extract is valuable in preventing atherogenesis. The superior effect of EC acetone extract warrants future studies to elucidate its mechanisms in the prevention of CVDs, particularly atherosclerosis.

Transcriptomic landscapes of effective and failed liver regeneration in humans

Although extensive experimental evidence on the process of liver regeneration exists, in humans, validation is largely missing. However, liver regeneration is critically affected by underlying liver disease. Within this project, we aimed to systematically assess early transcriptional changes during liver regeneration in humans and further assess how these processes differ in people with dysfunctional liver regeneration. Blood samples of 154 patients and intraoperative tissue samples of 46 patients undergoing liver resection were collected and classified with regard to dysfunctional postoperative liver regeneration. Of those, a matched cohort of 21 patients were used for RNA sequencing. Samples were assessed for circulating cytokines, gene expression dynamics, intrahepatic neutrophil accumulation, and spatial transcriptomics. Individuals with dysfunctional liver regeneration demonstrated an aggravated transcriptional inflammatory response with higher intracellular adhesion molecule-1 induction. Increased induction of this critical leukocyte adhesion molecule was associated with increased intrahepatic neutrophil accumulation and activation upon induction of liver regeneration in individuals with dysfunctional liver regeneration. Comparing baseline gene expression profiles in individuals with and without dysfunctional liver regeneration, we found that dual-specificity phosphatase 4 (DUSP4) expression, a known critical regulator of intracellular adhesion molecule-1 expression in endothelial cells, was markedly reduced in patients with dysfunctional liver regeneration. Mimicking clinical risk factors for dysfunctional liver regeneration, we found liver sinusoidal endothelial cells of two liver disease models to have significantly reduced baseline levels of DUSP4. Exploring the landscape of early transcriptional changes of human liver regeneration, we observed that people with dysfunctional regeneration experience overwhelming intrahepatic inflammation. Subclinical liver disease might account for DUSP4 reduction in liver sinusoidal endothelial cells, which ultimately primes the liver for an aggravated inflammatory response. Using a unique human biorepository, focused on liver regeneration (LR), we explored the landscape of circulating and tissue-level alterations associated with both functional and dysfunctional LR. In contrast to experimental animal models, people with dysfunctional LR demonstrated an aggravated transcriptional inflammatory response, higher intracellular adhesion molecule-1 (ICAM-1) induction, intrahepatic neutrophil accumulation and activation upon induction of LR. Although inflammatory responses appear rapidly after liver resection, people with dysfunctional LR have exaggerated inflammatory responses that appear to be related to decreased levels of LSEC DUSP4, challenging existing concepts of post-resectional LR.

TMIC-60. THE ROLE OF ICAM1 IN GLIOBLASTOMA TUMORIGENESIS UNDER HYPOXIC CONDITIONS

Abstract Glioblastoma (GBM) is a fatal brain cancer in adults with ineffective existing treatment methods. Cell adhesion molecules (CAMs) are proteins that are expressed on the surface of cells and enable them to interact with one another and the surrounding microenvironment. Intracellular adhesion molecule 1 (ICAM-1) is a cell adhesion molecule expressed by macrophages, tumor cells and endothelial cells in GBM. Preliminary data showed that ICAM-1 is associated with poorer overall and progression free survival in GBM patients and ICAM-1 expression levels increase in recurrent GBM tumors. TAMs enhance tumor growth and proliferation, within GBM. The goal of this study was to determine whether and how ICAM-1 expression on TAMs contributes to GBM tumorigenesis, specifically within the hypoxic tumor microenvironment. We hypothesized that ICAM1 facilitates TAM migration, proliferation and phagocytosis, thus enhancing tumor growth. We found that upon incubation of human and mouse primary macrophages in hypoxia, ICAM-1 expression levels increased and were further exasperated upon culturing with tumor cell-conditioned medium. Incubation of ICAM-1 deficient macrophages in hypoxia resulted in lower migration and proliferation in ICAM-1 deficient cells compared to wild type cells. When cultured with tumor cell condition media, migration and proliferation of ICAM-1 deficient macrophages was lower than wild type macrophages. Further, intracranial injection of tumor cells into ICAM-1 deficient and wild type mice revealed that ICAM1 deficient mice survived longer and had lower overall tumor volume than wild type mice. In conclusion, the expression of ICAM1 in TAMs likely promotes GBM tumorigenesis by enhancing their proliferation and migration into the tumor microenvironment. ICAM-1 plays a role in macrophage migration, proliferation, and its expression on TAMs, resulting in more aggressive and invasive tumors. In addition, certain environmental factors like hypoxia further enhance the expression of ICAM-1 in macrophages which is associated with more aggressive features of GBM.

9P The role of ICAM1 in glioblastoma tumor associated macrophages under hypoxia

Glioblastoma (GBM) is an aggressive and fatal brain cancer in adults with ineffective existing treatment methods. Intracellular adhesion molecule 1 (ICAM1) is a cell adhesion molecule expressed by tumor associated macrophages (TAMs) in GBM. TAMs enhance tumor growth and proliferation, particularly within the characteristic hypoxic tumor microenvironment (TME) of GBM. Hypothesis: I hypothesize that the expression of ICAM1 on the surface of TAMs contributes to GBM cell invasiveness, especially in the hypoxic TME, by enhancing the interaction between tumor cells and macrophages, thereby facilitating the migration, proliferation and invasion of the tumor cells.

A pulmonary endothelial amplification loop aggravates ex-vivo transfusion-related acute lung injury via increased toll-like receptor 4 and intra-cellular adhesion molecule-1 expression.

Transfusion-Related Acute Lung Injury (TRALI) is a life-threatening complication of blood transfusions characterized by pulmonary endothelial cell damage and edema, with a high incidence in critically ill patients. The pathophysiology of TRALI is unresolved, but can generally be hypothesized to follow a 2-hit model in which the first hit is elicited by the underlying clinical condition of the patient (e.g., inflammation, which can be reflected by LPS in experimental models), and the second hit is delivered by the blood transfusion product (e.g., HLA class I antibodies). Here, we report a synergistic role for LPS and HLA class I antibody binding to pulmonary endothelium resulting in enhanced inflammatory responses. Pulmonary endothelial cells were treated with PBS or low-dose LPS, exclusively or in combination with anti-HLA class I. Endothelial surface expression of HLA class I, TLR4, and inflammatory marker ICAM-1 were measured, and trans-endothelial migration (TEM) of neutrophils was investigated. LPS treatment of pulmonary endothelium enhanced HLA class I antibody binding, and combined LPS and HLA class I antibody binding enhanced TLR4 (LPS receptor) and ICAM-1 expression on the endothelial cell surface. Low-dose LPS and HLA antibody together also increased neutrophil TEM under physiological flow by on average 5-fold. We conclude that LPS and anti-HLA class I antibody have the ability to activate the pulmonary endothelium into a spiral of increasing inflammation, opening the opportunity to potentially block TLR4 to prevent or reduce the severity of TRALI in vivo.

BSCI-14 THE ROLE OF ICAM1 IN GLIOBLASTOMA TUMOUR ASSOCIATED MACROPHAGES UNDER HYPOXIC CONDITIONS

Abstract BACKGROUND Glioblastoma (GBM) is an aggressive and highly fatal brain cancer in adults. Existing treatment methods are ineffective and we are in need of new treatments that extend the overall survival and improve quality-of-life. Cell adhesion molecules (CAMs) are proteins that enable cells to communicate with one another and the surrounding environment. Intracellular adhesion molecule 1 (ICAM1) is a CAM expressed by TAMs in GBM. Tumour associated macrophages (TAMs) are thought to enhance tumour growth and proliferation, particularly within the characteristic hypoxic tumour microenvironment (TME) of GBM. I hypothesize that the expression of ICAM1 on the surface of TAMs contributes to GBM cell invasiveness, especially in the hypoxic TME, by enhancing the interaction between tumour cells and macrophages, thereby facilitating the migration and invasion of the tumour cells. METHODOLOGY Assess the expression levels of ICAM1 in primary and immortalized human and mouse macrophages under hypoxic conditions. Analyze the effect of ICAM1 deficiency on macrophage behaviour including migration, proliferation, and adhesion to tumour cells. Intracranially inject GL261 glioma cells in ICAM1 deficient and wild type mice. RESULTS ICAM1 is highly expressed in different cell types within the GBM microenvironment, including TAMs. The expression is particularly enhanced when primary or immortalized macrophages are treated with tumour cell-conditioned medium and is further exacerbated upon incubation of these cells in hypoxic conditions. The migration levels of bone marrow derived macrophage mouse cell type is higher in wild type cells than in ICAM1 deficient cells and higher when co-cultured with tumour cell condition media. ICAM1 deficient mice succumbed to GBM more quickly compared with wild type. CONCLUSIONS It is evident that the hypoxic tumour microenvironment increases the expression of ICAM1 in macrophages. The tumour microenvironment increases migration levels of macrophages. The expression of ICAM1 in TAMs in hypoxic TME promotes GBM cell invasiveness, proliferation, aggressiveness and migration.

Monocytic microparticles enhance proinflammatory cytokine secretion by monocytes and activate endothelial cells

Background: Monocytic microparticles (mMPs) are microparticles derived from activated human monocytes and play an important role in cell-to-cell communication in the circulation. Endothelial cells also exist in the circulation and are thought to have a complex interaction with the released mMPs. Both mMPs and endothelial cells are important players in inflammation. However, the underlying mechanism exerted by mMPs in modulating monocyte and endothelial cell activation during inflammation remains unclear. Methods: Monocytic THP-1 and U937 cells, as well as human blood monocytes, were cultured in the presence or absence of their corresponding mMPs prior to assessing tumor necrosis factor-a (TNF-a), interleukin 1b (IL-1b ), and interleukin 6 (IL-6) secretion. Upon the culture of human umbilical vein endothelial cells (HUVECs) in the presence or absence of mMPs, the expression of CD31, intracellular adhesion molecule 1 (ICAM-1), and vascular cell adhesion molecule 1 (VCAM-1) by HUVECs and endothelial microparticles (eMPs) was assessed. Results: Our results showed that THP-1 cells and stimulated monocyte-derived mMPs enhanced IL-1b and IL-6 secretion, respectively. Additionally, mMPs derived from stimulated monocytes enhanced the expression of CD31, ICAM-1, and VCAM-1 by HUVECs and increased the release of eMPs. Conclusion: These data suggest that mMPs may exacerbate inflammation through IL-1b and IL-6 activity and facilitate monocyte recruitment to inflammatory sites via CD31, ICAM-1, and VCAM-1.

Cucurbitacin B Down-Regulates TNF Receptor 1 Expression and Inhibits the TNF-α-Dependent Nuclear Factor κB Signaling Pathway in Human Lung Adenocarcinoma A549 Cells.

Pro-inflammatory cytokines, such as tumor necrosis factor-α (TNF-α), induce the expression of intracellular adhesion molecule-1 (ICAM-1) by activating the nuclear factor κB (NF-κB) signaling pathway. In the present study, we found that cucurbitacin B decreased the expression of ICAM-1 in human lung adenocarcinoma A549 cells stimulated with TNF-α or interleukin-1α. We further investigated the mechanisms by which cucurbitacin B down-regulates TNF-α-induced ICAM-1 expression. Cucurbitacin B inhibited the nuclear translocation of the NF-κB subunit RelA and the phosphorylation of IκBα in A549 cells stimulated with TNF-α. Cucurbitacin B selectively down-regulated the expression of TNF receptor 1 (TNF-R1) without affecting three adaptor proteins (i.e., TRADD, RIPK1, and TRAF2). The TNF-α-converting enzyme inhibitor suppressed the down-regulation of TNF-R1 expression by cucurbitacin B. Glutathione, N-acetyl-L-cysteine, and, to a lesser extent, L-cysteine attenuated the inhibitory effects of cucurbitacin B on the TNF-α-induced expression of ICAM-1, suggesting that an α,β-unsaturated carbonyl moiety is essential for anti-inflammatory activity. The present results revealed that cucurbitacin B down-regulated the expression of TNF-R1 at the initial step in the TNF-α-dependent NF-κB signaling pathway.

Direct Impact of Human Platelets on the Development of Transplant Arteriosclerosis.

Platelets play an important role in the pathogenesis of inflammatory and proliferative vascular changes. The aim of this study was to investigate whether human platelets are able to induce transplant arteriosclerosis in a humanized C57/Bl6-Rag2-/-γc-/- mouse xenograft model. Nonactivated and in vitro-activated human platelets were analyzed and phenotyped for surface markers by flow cytometry. Side branches of human mammary arteries were implanted into the infrarenal aorta of recipients, followed by daily application of human platelets and histological analyzed on day 30 after transplantation. Human platelets collected by apheresis had low levels of platelet activation markers. However, after in vitro activation, expression was markedly increased. Sixty minutes after injection in recipient mice, nonactivated human platelets become significantly activated. Increased adhesion of platelets to the vascular endothelium was detected by in vivo fluorescence microscopy. After intravenous injection of nonactivated or activated platelets, human xenografts showed pronounced intimal proliferation. Immunohistological analysis showed that the group treated with activated human platelets exhibited significantly increased intragraft protein expression of intracellular adhesion molecule-1 and platelet-derived growth factor receptor beta and smooth muscle cell migration into the neointima. These data demonstrate that an isolated daily application of both in vivo- and in vitro-activated human platelets results in the development of transplant arteriosclerosis in a humanized mouse transplantation model.

Extracellular vesicles from ALI models induce endothelial dysfunction

One distinguishing characteristic of acute respiratory distress syndrome (ARDS) or its lesser form, acute lung injury (ALI), is dysfunction of the lung endothelium. This dysfunction leads to increased permeability and eventual pulmonary edema. Despite the globally climbing rates of ARDS, the mechanisms of endothelial dysfunction are poorly understood. Recently, extracellular vesicles (EVs) have been shown to induce various microvascular disease states, as they contain various endothelial‐targeting cargo in the form of mRNA, proteins, lipids, and miRNAs. Therefore, we hypothesized that EVs play a role in the endothelial dysfunction observed in ARDS/ALI. EVs were isolated from the plasma of male Sprague Dawley rats which were given saline or P. aeruginosa (PA103) via intratracheal (IT) injection for 48h. ALI was confirmed by determining the wet to dry weights of the rodent lungs. We then tested the effect of the EVs isolated from saline‐ and ALI treated animals (sEVs and ALI‐EVs, respectively) on endothelial barrier function and modifications in gene expression. We found that treatment with ALI‐EVs, but not sEVs, increased rat lung microvascular endothelial cell (RLMVEC) permeability in the presence of lipopolysaccharide (LPS). Interestingly, ALI‐EVs did not induce endothelial dysfunction on their own, rather exacerbated the damage induced by LPS. We further noted ALI‐EVs, but not sEVs, increased gene expression of toll‐like receptor 4 (TLR4), which is the main pattern recognition receptor (PRR) for LPS and its downstream signaling molecule, MyD88 in the presence of LPS in RLMVEC. Further, we found that ALI‐EVs, together with LPS, increased gene expression of intracellular adhesion molecule 1 (ICAM‐1), vascular adhesion molecule 1 (VCAM‐1), and interleukin 6 (IL‐6), which are all involved in inflammatory signaling. Thus, it is likely that through the modulation of inflammatory signaling mediators, ALI‐EVs contain select cargo that worsen the endothelial barrier in settings where LPS is present, such as bacterial‐ARDS.

Endothelial dysfunction caused by circulating microparticles from diabetic mice is reduced by PD98059 through ERK and ICAM-1

Endothelial dysfunction contributes to the development of diabetic complications and the production of circulating microparticles (MPs). Our previous study showed that diabetic mice-derived MPs (DM MPs) had increased levels of extracellular regulated protein kinase 1/2 (ERK1/2) and impaired endothelial-dependent relaxation in aortas when compared with control mice-derived MPs. This study was designed to investigate whether PD98059, an ERK1/2 inhibitor, affects the function of aortas and DM MPs. MPs were obtained from streptozotocin-induced DM, DM after PD98059 treatment, and ICR mice as control. The mice and MPs were then analyzed on the basis of their vascular function and enzyme expressions. Compared with the controls, platelet-derived MPs and ERK1/2 levels in the MPs were significantly elevated in the DM but showed little change in PD98059-treated DM. PD98059 mainly decreased ERK1/2 phosphorylation in the MPs. In the aortas of DM and DM MPs the endothelium-dependent vascular function was impaired, and there was a significantly greater improvement in the vascular function in the PD98059-treated DM aortas and the aortas treated with PD98059-treated DM MPs than in DM aortas and the aortas treated with DM MPs. Furthermore, DM MPs increased ERK1/2 and intracellular adhesion molecule-1 (ICAM-1) expressions in the aortas, but PD98059-treated DM MPs did not show these effects. For the first time, these results indicate that PD98059 treatment improves endothelial dysfunction in DM, and adhesion properties of DM MPs can be partly blocked by PD98059 via ERK and ICAM-1. These effects may explain some of the vascular complications in diabetes.