CD40 is essential in the upregulation of TRAF proteins and NF-kappaB-dependent proinflammatory gene expression after arterial injury

Decoding the contextual duality of CD40 functions

Previously, we established that as a function of its mode of interaction with its ligand or cellular conditions such as membrane lipids, preexisting signaling intermediates activation status, a transmembrane receptor, as represented here with CD40, can induce counteractive cellular responses. Using CD40-binding peptides, recombinant mutated CD40-ligands, and an agonistic antibody, we have established the functional duality of CD40. CD40 builds up two constitutionally different signalosomes on lipid raft and non-raft membrane domains initiating two different signaling pathways. Although this initial signaling may be modified by the pre-existing signaling conditions downstream and may be subjected to feed-forward or negative signaling effects, the initial CD40-CD40L interaction plays a crucial role in the functional outcome of CD40. Herein, we have reviewed the influence of interaction between the CD40-CD40L evoking the functional duality of CD40 contingent upon different physiological states of the cells.

CD40 Upregulation in the Retina of Patients With Diabetic Retinopathy: Association With TRAF2/TRAF6 Upregulation and Inflammatory Molecule Expression

Purpose

CD40 is upregulated in the retinas of diabetic mice, drives pro-inflammatory molecule expression, and promotes diabetic retinopathy. The role of CD40 in diabetic retinopathy in humans is unknown. Upregulation of CD40 and its downstream signaling molecules TNF receptor associated factors (TRAFs) is a key feature of CD40-driven inflammatory disorders. We examined the expression of CD40, TRAF2, and TRAF6 as well as pro-inflammatory molecules in retinas from patients with diabetic retinopathy.

Methods

Posterior poles from patients with diabetic retinopathy and non-diabetic controls were stained with antibodies against von Willebrand factor (labels endothelial cells), cellular retinaldehyde-binding protein (CRALBP), or vimentin (both label Müller cells) plus antibodies against CD40, TRAF2, TRAF6, ICAM-1, CCL2, TNF-α, and/or phospho-Tyr783 phospholipase Cγ1 (PLCγ1). Sections were analyzed by confocal microscopy.

Results

CD40 expression was increased in endothelial and Müller cells from patients with diabetic retinopathy. CD40 was co-expressed with ICAM-1 in endothelial cells and with CCL2 in Müller cells. TNF-α was detected in retinal cells from these patients, but these cells lacked endothelial/Müller cell markers. CD40 in Müller cells from patients with diabetic retinopathy co-expressed activated phospholipase Cγ1, a molecule that induces TNF-α expression in myeloid cells in mice. CD40 upregulation in endothelial cells and Müller cells from patients with diabetic retinopathy was accompanied by TRAF2 and TRAF6 upregulation.

Conclusions

CD40, TRAF2, and TRAF6 are upregulated in patients with diabetic retinopathy. CD40 associates with expression of pro-inflammatory molecules. These findings suggest that CD40-TRAF signaling may promote pro-inflammatory responses in the retinas of patients with diabetic retinopathy.

Extensive involvement of CD40 and CD154 costimulators in multiple T cell-mediated responses in a perciform fish Larimichthys crocea

CD40 and CD154 are well-characterized costimulatory molecules involved in adaptive humoral immunity in humans and other mammals. These two costimulatory molecules were found to be originated from teleost fish during vertebrate evolution. However, the functionality of fish CD40 and CD154 remains to be explored. In this study, we identified the CD40 and CD154 homologs (LcCD40 and LcCD154) from large yellow croaker (Larimichthys crocea), a marine species of the perciform fish family. The LcCD40 and LcCD154 share conserved structural features to their mammalian counterparts, and are widely expressed in immune-relevant tissues and leukocytes at different transcriptional levels. Immunofluorescence staining and FCM analysis showed that LcCD40 and LcCD154 proteins are distributed on MHC-II⁺ APCs and CD4-2⁺ T cells, and are significantly upregulated in response to antigen stimulation. Co-IP assay exhibited strong association between LcCD40 and LcCD154 proteins. Blockade of LcCD154 with anti-LcCD154 antibody (Ab) or recombinant soluble LcCD40-Ig fusion protein remarkably decreased the MHC-II⁺ APC-initiated CD4⁺ T cell response upon Aeromonas hydrophila stimulation, and alloreactive T cell activation as examined by mixed lymphocyte reaction (MLR). These findings highlight the costimulatory role of LcCD40 and LcCD154 in T cell activities in Larimichthys crocea. Thus, the CD40 and CD154 costimulators may extensively participate in the regulation of multiple T cell-mediated immune responses in teleost fish. It is anticipated that this study would provide a cross-species understanding of the evolutionary history of CD40 and CD154 costimulatory signals from fish to mammals.

The Role of Tumor Necrosis Factor Associated Factors (TRAFs) in Vascular Inflammation and Atherosclerosis

TNF receptor associated factors (TRAFs) represent a family of cytoplasmic signaling adaptor proteins that regulate, bundle, and transduce inflammatory signals downstream of TNF- (TNF-Rs), interleukin (IL)-1-, Toll-like- (TLRs), and IL-17 receptors. TRAFs play a pivotal role in regulating cell survival and immune cell function and are fundamental regulators of acute and chronic inflammation. Lately, the inhibition of inflammation by anti-cytokine therapy has emerged as novel treatment strategy in patients with atherosclerosis. Likewise, growing evidence from preclinical experiments proposes TRAFs as potent modulators of inflammation in atherosclerosis and vascular inflammation. Yet, TRAFs show a highly complex interplay between different TRAF-family members with partially opposing and overlapping functions that are determined by the level of cellular expression, concomitant signaling events, and the context of the disease. Therefore, inhibition of specific TRAFs may be beneficial in one condition and harmful in others. Here, we carefully discuss the cellular expression and signaling events of TRAFs and evaluate their role in vascular inflammation and atherosclerosis. We also highlight metabolic effects of TRAFs and discuss the development of TRAF-based therapeutics in the future.

Interfering hsa_circ_0073748 alleviates caerulein-induced ductal cell injury in acute pancreatitis by inhibiting miR-132-3p/TRAF3/NF-κB pathway

Circular RNA hsa_circ_0073748 (circ_0073748) is upregulated in patients with acute pancreatitis (AP), a clinically common sudden inflammatory response. MicroRNA (miR)-132-3p is a stress-induced factor with high conservation between species. Herein, expression and role of circ_0073748 and miR-132-3p in caerulein-induced pancreatitis were studied. Expression levels of circ_0073748, miR-132-3p, TNF receptor associated factor 3 (TRAF3), Bcl-2 and Bcl-2-associated X protein (Bax) were examined by reverse transcription-quantitative PCR and Western blotting. Cell proliferation was measured by MTS and EdU assays. Flow cytometry and assay kits detected apoptosis, inflammatory, and oxidative responses. Western blotting detected nuclear factor (NF)-κB signaling pathway. Circ_0073748 was upregulated and miR-132-3p was downregulated in AP patients' plasma and human pancreatic ductal HPDE6-C7 cells with caerulein induction. Interfering circ_0073748 and reinforcing miR-132-3p improved cell viability, EdU incorporation, and superoxide dismutase (SOD) activity of caerulein-treated HPDE6-C7 cells but suppressed malonaldehyde (MDA), IL-6 and TNF-α levels and apoptosis rate. Moreover, TRAF3 downregulation was allied with circ_0073748 silencing and miR-132-3p overexpression in caerulein-induced HPDE6-C7 cells. Mechanically, circ_0073748 was identified as a sponge for miR-132-3p to modulate TRAF3 expression, thus establishing a competitive endogenous RNA (ceRNA) regulation model. Notably, circ_0073748 blockage could suppress expressions of phosphorylated P65 (p-P65) and p-IκB in caerulein-induced HPDE6-C7 cells by promoting miR-132-3p and inhibiting TRAF3. Silencing circ_0073748 and upregulating miR-132-3p could alleviate caerulein-induced HPDE6-C7 injury and inactivate canonical NF-κB signal by inhibiting TRAF3. Circ_0073748/miR-132-3p/TRAF3 ceRNA pathway might be one underlying mechanism and therapeutic target of caerulein-induced AP.

NAFLD as a continuous driver in the whole spectrum of vascular disease

Vascular disease is the prime determinant to cardiovascular morbidities and mortalities, which comprises the early vascular damage and subsequent cardiovascular events. Non-alcohol Fatty Liver Disease (NAFLD) is a systemic metabolic disorder that drives the progression of vascular disease through complex interactions. Although a causal relationship between NAFLD and cardiovascular disease (CVD) has not been established, a growing number of epidemiological studies have demonstrated an independent association between NAFLD and early vascular disease and subsequent cardiovascular events. In addition, mechanistic studies suggest that NAFLD initiates and accelerates vascular injury by increasing systemic inflammation and oxidative stress, impairing insulin sensitivity and lipid metabolism, and modulating epigenetics, the intestinal flora and hepatic autonomic nervous system; thus, NAFLD is a putative driving force for CVD progression. In this review, we summarize the clinical evidence supporting the association of NAFLD with subclinical vascular disease and cardiovascular events and discuss the potential mechanisms by which NAFLD promotes the progression of vascular disease.

Role of miR-145-5p/ CD40 in the inflammation and apoptosis of HUVECs induced by PM2.5

Fine particulate matter (PM_2.5) exposure can cause the injury of vascular endothelial cells by inflammatory response. CD40 works in inflammation of endothelial cells and it may be regulated by the miRNAs. This study aimed to clarify the role and mechanism of CD40 and miR-145-5p in PM_2.5-induced injury of human umbilical vein endothelial cells (HUVECs). HUVECs were treated with different concentrations of PM_2.5 exposure (0, 100, 200, 400 μg/mL) for 24 h. The si-RNA was used for CD40 gene silencing (0, 200 μg/mL PM_2.5, siRNA-CD40 and siRNA-CD40 + 200 μg/mL PM_2.5). Mimics was used for overexpression of miR-145-5p (0, 200 μg/mL PM_2.5, mimics and mimics+200 μg/mL PM_2.5). The cell viability of HUVECs was detected with Cell Counting Kit8 (CCK8) kit. The level of cell apoptosis was detected by flow cytometry. The inflammation-related factor including interleukin-1β (IL-1β), interleukin-18 (IL-18), tumor necrosis factor α (TNF-α) and C1q complement/tumor necrosis factor (TNF)-associated proteins9 (CTRP9) were tested with enzyme-linked immunosorbent assay (ELISA) kits. The mRNA and protein expression levels of CD40, CD40L, caspase1, NLRP3 (Nod-like receptor family pyrin domain-containing 3) and IKKB were detected with quantitative real-time PCR (qRT-PCR), Western blot and Immunofluorescence. Compared with the control group, the cell viability of HUVECs exposed to PM_2.5 was significantly decreased (p < 0.05); the levels of IL-Iβ and TNF-α were significantly increased, while the level of CTRP9 was significantly decreased (p < 0.05). The proportion of apoptotic cells was increased after being treated with PM_2.5 (p < 0.05). Besides, the mRNA and protein levels of CD40, CD40L, IKKB, NLRP3 and caspase1 were increased comparing with the control group (p < 0.05). After CD40 silencing, the condition of inflammation and apoptosis in HUVECs exposed to PM_2.5 was alleviated, and the expression levels of CD40L, IKKB, NLRP3 and caspase1 were significantly decreased (p < 0.05). Furthermore, miR-145-5p was significantly down-regulated after exposure to 200μg/mL PM_2.5 (p < 0.05). After over-expression of miR-145-5p, the expression level of CD40 was decreased (p < 0.05). Taken together, PM_2.5 can cause inflammation and apoptosis of HUVECs via the activation of CD40, which can be regulated by miR-145-5p. Over-expression of miR-145-5p can down-regulate CD40, further inhibiting the inflammation and apoptosis of HUVECs induced by PM_2.5.

CD40L modulates transcriptional signatures of neutrophils in the bone marrow associated with development and trafficking

Neutrophils are produced in the BM in a process called granulopoiesis, in which progenitor cells sequentially develop into mature neutrophils. During the developmental process, which is finely regulated by distinct transcription factors, neutrophils acquire the ability to exit the BM, properly distribute throughout the body, and migrate to infection sites. Previous studies have demonstrated that CD40 ligand (CD40L) influences hematopoiesis and granulopoiesis. Here, we investigate the effect of CD40L on neutrophil development and trafficking by performing functional and transcriptome analyses. We found that CD40L signaling plays an essential role in the early stages of neutrophil generation and development in the BM. Moreover, CD40L modulates transcriptional signatures, indicating that this molecule enables neutrophils to traffic throughout the body and to migrate in response to inflammatory signals. Thus, our study provides insights into the complex relationships between CD40L signaling and granulopoiesis, and it suggests a potentially novel and nonredundant role of CD40L signaling in neutrophil development and function.

Downregulation of long noncoding RNA SNHG7 protects against inflammation and apoptosis in Parkinson's disease model by targeting the miR-425-5p/TRAF5/NF-κB axis

Accumulated evidence has manifested that long noncoding RNA (lncRNA) is involved in the progress of Parkinson's disease (PD). SNHG7, a novel lncRNA, has been found to be involved in tumorigenesis. However, SNHG7 expression and its functional effects on PD remain uncharted. Rotenone (Rot) was adopted to construct PD models in Sprague-Dawley (SD) rats and SH-SY5Y cells, respectively. The expression levels of caspase 3, tyrosine hydroxylase (TH), ionized calcium-binding adapter molecule 1 (Iba1) in SD rat striatum were measured via immunohistochemistry and western blot. Additionally, the expressions of inflammatory cytokines (interleukin 1β [IL-1β], IL-6, tumor necrosis factor α) and oxidative stress factors (malondialdehyde, superoxide dismutase, and glutathione peroxidase) in the brain tissues were examined using real-time polymerase chain reaction and enzyme-linked immunosorbent assay, respectively. Moreover, the protein levels of tumor necrosis factor receptor-associated factor (TRAF5), I-κB, nuclear factor-κB (NF-κB), HO-1, Nrf2 were detected via western blot. Bioinformatics was applied to predict the targeting relationship between SNHG7, miR-425-5p, and TRAF5. Dual-luciferase activity assay and RNA immunoprecipitation assays were conducted to verify their interactions. In comparison to healthy donors, SNHG7 was found upregulated while miR-425-5p expression was downregulated in PD patients. Functional experiments confirmed that SNHG7 downregulation or miR-425-5p overexpression attenuated neuronal apoptosis in the Rot-mediated PD model, TH-positive cell loss, and microglial activation by mitigating inflammation and oxidative stress. Mechanistically, SNHG7 served as a competitive endogenous RNA by sponging miR-425-5p and promoted TRAF5 mediated inflammation and oxidative stress. Inhibition of SNHG7 ameliorated neuronal apoptosis in PD through relieving miR-425-5p/TRAF5/NF-κB signaling pathway modulated inflammation and oxidative stress, and similar results were observed in the Rot-mediated rat model of PD.

Cangrelor alleviates bleomycin-induced pulmonary fibrosis by inhibiting platelet activation in mice

Pulmonary fibrosis is a progressive chronic inflammatory lung disease whose pathogenesis is complicated. Platelets and neutrophils play important roles in the progression of pulmonary inflammation. We have reported that cangrelor, a non-sepesific GPR17 antagonist, alleviates pulmonary fibrosis partly by inhibiting macrophage inflammation in mice. Cangrelor is also a well-known anti-platelet agent. To test whether cangrelor mitigated pulmonary fibrosis partly through the inhibition of platelets, bleomycin (BLM) was used to induce pulmonary fibrosis in C57BL/6 J mice. We found that cangrelor (10 mg/kg) not only significantly decreased BLM-induced release of inflammatory cytokines (PF4, CD40 L and MPO), but also decreased the increment of platelets, neutrophils and platelet-neutrophil aggregates in the fibrotic lung and in the peripheral blood of BLM-treated mice. In addition, cangrelor decreased the number of CD40 and MPO double positive neutrophils and the expression level of CD40 in BLM-treated mouse lungs. Based on these results we conclude that cangrelor alleviates BLM-induced lung inflammation and pulmonary fibrosis in mice, partly through inhibition of platelet activation, therefore reducing the infiltration of neutrophils due to the adhesion of platelets and neutrophils mediated by CD40 - CD40 L interaction. Cangrelor could be a potential therapeutic medicine for pulmonary fibrosis.

Tumor Necrosis Factor Receptor-Associated Factor 5 Promotes Arterial Neointima Formation through Smooth Muscle Cell Proliferation

Tumor necrosis factor (TNF) receptor-associated factors (TRAFs) are cytoplasmic adaptor proteins of the TNF/interleukin (IL)-1/Toll-like receptor superfamily. Ligands of this family such as TNFα, CD40L, and IL-1β promote chronic inflammatory processes such as atherosclerosis and restenosis, the latter being a common adverse reaction after vascular interventions. We previously reported overexpression of TRAF5 in murine and human atheromata and TRAF5-dependent proinflammatory functions in vitro. However, the role of TRAF5 in restenosis remains unsettled. To evaluate whether TRAF5 affects neointima formation, TRAF5-/-LDLR-/- and TRAF5+/+LDLR-/- mice consuming a high cholesterol diet (HCD) received wire-induced injury of the carotid artery. After 28 days, TRAF5-deficient mice showed a 45% decrease in neointimal area formation compared with TRAF5-compentent mice. Furthermore, neointimal vascular smooth muscle cells (vSMC) and macrophages decreased whereas collagen increased in TRAF5-deficient mice. Mechanistically, the latter expressed lower transcript levels of the matrix metalloproteinases 2 and 9, both instrumental in extracellular matrix degradation and vSMC mobilization. Additionally, TRAF5-specific siRNA interference rendered murine vSMC less proliferative upon CD40L stimulation. In accordance with these findings, fewer vSMC isolated from TRAF5-deficient aortas were in a proliferative state as assessed by Ki67 and cyclin B1 expression. In conclusion, TRAF5 deficiency mitigates neointima formation in mice, likely through a TRAF5-dependent decrease in vSMC proliferation.

Xenogeneic Transplantation of Human Placenta-Derived Mesenchymal Stem Cells Alleviates Renal Injury and Reduces Inflammation in a Mouse Model of Lupus Nephritis

Human placenta-derived mesenchymal stem cells (pMSCs) are considered a good source for cell therapy. The purpose of this study was to observe whether the transplantation of human pMSCs would affect the treatment of lupus nephritis (LN)-prone MRL/lpr mice. Multiple injections (at the 16th, 18th, and 20th week of age) of 1 × 106 pMSCs were administered. Urine was collected to evaluate proteinuria and urine creatinine levels. Blood was collected for the measurement of serum antinuclear antibody (ANA) and anti-double-stranded DNA (dsDNA) antibody levels. Renal tissues were collected for histological staining and examination by light and electron microscopy quantitative reverse transcription polymerase chain reaction (RT-qPCR) and Western Blot. The results confirmed that pMSC treatment reduced the severity of 24-h proteinuria, decreased the production of anti-dsDNA antibodies, and ameliorated renal pathological changes in MRL/lpr mice. Furthermore, pMSCs reduced renal inflammation by inhibiting the expression of nuclear factor kappa B (NF-κB) and then downregulating the expression of tumor necrosis factor-α (TNF-α), intercellular cell adhesion molecule-1 (ICAM-1), and plasminogen activator inhibitor-1 (PAI-1). Therefore, our present study demonstrated a protective effect of pMSCs against renal injury and inflammation in MRL/lpr mice.

Innate Immune Signaling and Its Role in Metabolic and Cardiovascular Diseases

The innate immune system is an evolutionarily conserved system that senses and defends against infection and irritation. Innate immune signaling is a complex cascade that quickly recognizes infectious threats through multiple germline-encoded cell surface or cytoplasmic receptors and transmits signals for the deployment of proper countermeasures through adaptors, kinases, and transcription factors, resulting in the production of cytokines. As the first response of the innate immune system to pathogenic signals, inflammatory responses must be rapid and specific to establish a physical barrier against the spread of infection and must subsequently be terminated once the pathogens have been cleared. Long-lasting and low-grade chronic inflammation is a distinguishing feature of type 2 diabetes and cardiovascular diseases, which are currently major public health problems. Cardiometabolic stress-induced inflammatory responses activate innate immune signaling, which directly contributes to the development of cardiometabolic diseases. Additionally, although the innate immune elements are highly conserved in higher-order jawed vertebrates, lower-grade jawless vertebrates lack several transcription factors and inflammatory cytokine genes downstream of the Toll-like receptors (TLRs) and retinoic acid-inducible gene-I (RIG-I)-like receptors (RLRs) pathways, suggesting that innate immune signaling components may additionally function in an immune-independent way. Notably, recent studies from our group and others have revealed that innate immune signaling can function as a vital regulator of cardiometabolic homeostasis independent of its immune function. Therefore, further investigation of innate immune signaling in cardiometabolic systems may facilitate the discovery of new strategies to manage the initiation and progression of cardiometabolic disorders, leading to better treatments for these diseases. In this review, we summarize the current progress in innate immune signaling studies and the regulatory function of innate immunity in cardiometabolic diseases. Notably, we highlight the immune-independent effects of innate immune signaling components on the development of cardiometabolic disorders.

Trichomonas vaginalis Induces Production of Proinflammatory Cytokines in Mouse Macrophages Through Activation of MAPK and NF-κB Pathways Partially Mediated by TLR2

Trichomoniasis, caused by Trichomonas vaginalis infection, is the most prevalent sexually transmitted disease in female and male globally. However, the mechanisms by innate immunity against T. vaginalis infection have not been fully elucidated. Toll-like receptor2 (TLR2) has been shown to be involved in pathogen recognition, innate immunity activation, and inflammatory response to the pathogens. Nonetheless, the function of TLR2 against T. vaginalis remains unclear. In the present study, we investigated the role of TLR2 in mouse macrophages against T. vaginalis. RT-qPCR analysis revealed that T. vaginalis stimulation increased the gene expression of TLR2 in wild-type (WT) mouse macrophages. T. vaginalis also induced the secretion of IL-6, TNF-α, and IFN-γ in WT mouse macrophages, and the expression of these cytokines significantly decreased in TLR^2-/- mouse macrophages and in WT mouse macrophages pretreated with MAPK inhibitors SB203580 (p38) and PD98059 (ERK). Western blot analysis demonstrated that T. vaginalis stimulation induced the activation of p38, ERK, and p65 NF-κB signal pathways in WT mouse macrophages, and the phosphorylation of p38, ERK, and p65 NF-κB significantly decreased in TLR2^-/- mouse macrophages. Taken together, our data suggested that T. vaginalis may regulates proinflammatory cytokines production by activation of p38, ERK, and NF-κB p65 signal pathways via TLR2 in mouse macrophages. TLR2 might be involved in the defense and elimination of T. vaginalis infection.

CD40 ligand deficiency causes functional defects of peripheral neutrophils that are improved by exogenous IFN-γ

BACKGROUND

Patients with X-linked hyper-IgM syndrome caused by CD40 ligand (CD40L) deficiency often present with episodic, cyclic, or chronic neutropenia, suggesting abnormal neutrophil development in the absence of CD40L-CD40 interaction. However, even when not neutropenic and despite immunoglobulin replacement therapy, CD40L-deficient patients are susceptible to life-threatening infections caused by opportunistic pathogens, suggesting impaired phagocyte function and the need for novel therapeutic approaches.

OBJECTIVES

We sought to analyze whether peripheral neutrophils from CD40L-deficient patients display functional defects and to explore the in vitro effects of recombinant human IFN-γ (rhIFN-γ) on neutrophil function.

METHODS

We investigated the microbicidal activity, respiratory burst, and transcriptome profile of neutrophils from CD40L-deficient patients. In addition, we evaluated whether the lack of CD40L in mice also affects neutrophil function.

RESULTS

Neutrophils from CD40L-deficient patients exhibited defective respiratory burst and microbicidal activity, which were improved in vitro by rhIFN-γ but not soluble CD40L. Moreover, neutrophils from patients showed reduced CD16 protein expression and a dysregulated transcriptome suggestive of impaired differentiation. Similar to CD40L-deficient patients, CD40L knockout mice were found to have impaired neutrophil responses. In parallel, we demonstrated that soluble CD40L induces the promyelocytic cell line HL-60 to proliferate and mature by regulating the expression of genes of the same Gene Ontology categories (eg, cell differentiation) when compared with those dysregulated in peripheral blood neutrophils from CD40L-deficient patients.

CONCLUSION

Our data suggest a nonredundant role of CD40L-CD40 interaction in neutrophil development and function that could be improved in vitro by rhIFN-γ, indicating a potential novel therapeutic application for this cytokine.

Role of TRAF3 in neurological and cardiovascular diseases: an overview of recent studies

Tumour necrosis factor receptor-associated factor 3 (TRAF3) is a member of the TRAF adaptor protein family, which exerts different effects on the cell depending on the receptor to which it binds and the cell type in which it is expressed. TRAF3 is a major regulator of the innate immune response. To perform its functions properly, TRAF3 is transcriptionally and epigenetically regulated. At the transcriptional level, TRAF3 expression has been associated with neurological and cardiovascular diseases including stroke, among other pathologies. Epigenetic modifications of TRAF3 have been observed at the histone and DNA levels. It has been observed that acetylation of TRAF3, as well as other NF-κβ target genes, is associated with cardiac hypertrophy. Furthermore, TRAF3 methylation has been associated with vascular recurrence after ischemic stroke in patients treated with clopidogrel. In this overview, we summarise the most interesting studies related to transcriptional and epigenetic regulation of TRAF3 focusing on those studies performed in neurological and cardiovascular diseases.

Platelet CD40 Mediates Leukocyte Recruitment and Neointima Formation after Arterial Denudation Injury in Atherosclerosis-Prone Mice

The role of platelets in the development of thrombosis and abrupt closure after angioplasty is well recognized. However, the direct impact of platelets on neointima formation after arterial injury remains undetermined. Herein, we show that neointima formation after carotid artery wire injury reduces markedly in CD40-/- apolipoprotein E-deficient (apoE-/-) mice but only slightly in CD40 ligand-/-apoE-/- mice, compared with apoE-/- mice. Wild-type and CD40-deficient platelets were isolated from blood of apoE-/- and CD40-/-apoE-/- mice, respectively. The i.v. injection of thrombin-activated platelets into CD40-/-apoE-/- mice was performed every 5 days, starting at 2 days before wire injury. Injection of wild-type platelets promoted neointima formation, which was associated with increased inflammation by stimulating leukocyte recruitment via up-regulation of circulating platelet surface P-selectin expression and the formation of platelet-leukocyte aggregates. It was also associated with further promoting the luminal deposition of platelet-derived regulated on activation normal T cell expressed and secreted/chemokine (C-C motif) ligand 5 and expression of monocyte chemoattractant protein-1 and vascular cell adhesion molecule 1 in wire-injured carotid arteries. Remarkably, all these inflammatory actions by activated platelets were abrogated by lack of CD40 on injected platelets. Moreover, injection of wild-type platelets inhibited endothelial recovery in wire-injured carotid arteries, but this effect was also abrogated by lack of CD40 on injected platelets. Results suggest that platelet CD40 plays a pivotal role in neointima formation after arterial injury and might represent an attractive target to prevent restenosis after vascular interventions.

DNA Methylation in Stroke. Update of Latest Advances

Epigenetic modifications are hereditable and modifiable factors that do not alter the DNA sequence. These epigenetic factors include DNA methylation, acetylation of histones and non-coding RNAs. Epigenetic factors have mainly been associated with cancer but also with other diseases and conditions such as diabetes or obesity. In addition, epigenetic modifications could play an important role in cardiovascular diseases, including stroke. We review the latest advances in stroke epigenetics, focusing on DNA methylation studies and the future perspectives in this field.

Interruption of classic CD40L-CD40 signalling but not of the novel CD40L-Mac-1 interaction limits arterial neointima formation in mice

The co-stimulatory immune molecule CD40L figures prominently in a variety of inflammatory conditions including arterial disease. Recently, we made the surprising finding that CD40L mediates atherogenesis independently of its classic receptor CD40 via a novel interaction with the leukocyte integrin Mac-1. Here, we hypothesised that selective blockade of the CD40L-Mac-1 interaction may also retard restenosis. We induced neointima formation in C57/BL6 mice by ligation of the left carotid artery. Mice were randomised to daily intraperitoneal injections of either cM7, a small peptide selectively inhibiting the CD40L-Mac-1 interaction, scM7, a scrambled control peptide, or saline for 28 days. Interestingly, cM7-treated mice developed neointima of similar size compared with mice receiving the control peptide or saline as assessed by computer-assisted analysis of histological cross sections. These data demonstrate that the CD40L-Mac-1 interaction is not required for the development of restenosis. In contrast, CD40-deficient mice subjected to carotid ligation in parallel, developed significantly reduced neointimal lesions compared with respective wild-type controls (2872 ± 843 µm² vs 35469 ± 11870 µm²). Flow cytometry in CD40-deficient mice revealed reduced formation of platelet-granulocyte and platelet-inflammatory monocyte-aggregates. In vitro, supernatants of CD40-deficient platelet-leukocyte aggregates attenuated proliferation and increased apoptosis of smooth muscle cells. Unlike in the setting of atherosclerosis, CD40L mediates neointima formation via its classic receptor CD40 rather than via its recently described novel interaction with Mac-1. Therefore, selective targeting of CD40L-Mac-1 binding does not appear to be a favorable strategy to fight restenosis.

Pharmacokinetic and Pharmacodynamic Responses to Clopidogrel: Evidences and Perspectives

Clopidogrel has significantly reduced the incidence of recurrent atherothrombotic events in patients with acute coronary syndrome (ACS) and in those undergoing percutaneous coronary intervention (PCI). However, recurrence events still remain, which may be partly due to inadequate platelet inhibition by standard clopidogrel therapy. Genetic polymorphisms involved in clopidogrel’s absorption, metabolism, and the P2Y12 receptor may interfere with its antiplatelet activity. Recent evidence indicated that epigenetic modification may also affect clopidogrel response. In addition, non-genetic factors such as demographics, disease complications, and drug-drug interactions can impair the antiplatelet effect of clopidogrel. The identification of factors contributing to the variation in clopidogrel response is needed to improve platelet inhibition and to reduce risk for cardiovascular events. This review encompasses the most recent updates on factors influencing pharmacokinetic and pharmacodynamic responses to clopidogrel.

Platelet CD40L induces activation of astrocytes and microglia in hypertension

Studies have demonstrated separately that hypertension is associated with platelet activation in the periphery (resulting in accumulation and localized inflammatory response) and glial activation in the brain. We investigated the contribution of platelets in brain inflammation, particularly glial activation in vitro and in a rat model of hypertension. We found that HTN increased the expression of adhesion molecules like JAM-1, ICAM-1, and VCAM-1 on brain endothelium and resulted in the deposition of platelets in the brain. Platelet deposition in hypertensive rats was associated with augmented CD40 and CD40L and activation of astrocytes (GFAP expression) and microglia (Iba-1 expression) in the brain. Platelets isolated from hypertensive rats had significantly higher sCD40L levels and induced more prominent glial activation than platelets from normotensive rats. Activation of platelets with ADP induced sCD40L release and activation of astrocytes and microglia. Moreover, CD40L induced glial (astrocytes and microglia) activation, NFкB and MAPK inflammatory signaling, culminating in neuroinflammation and neuronal injury (increased apoptotic cells). Importantly, injection of ADP-activated platelets into normotensive rats strongly induced activation of astrocytes and microglia and increased plasma sCD40L levels compared with control platelets. On the contrary, inhibition of platelet activation by Clopidogrel or disruption of CD40 signaling prevented astrocyte and microglial activation and provided neuroprotection in both in vivo and in vitro conditions. Thus, we have identified platelet CD40L as a key inflammatory molecule for the induction of astrocyte and microglia activation, the major contributors to inflammation-mediated injury in the brain.

An inflammatory link in atherosclerosis and obesity. Co-stimulatory molecules

Atherosclerosis and obesity-induced metabolic dysfunction are lipid-driven inflammatory pathologies responsible for a major part of cardiovascular complications. Immune cell activation as well as interactions between the different immune cells is dependent on and controlled by a variety of co-stimulatory signals. These co-stimulatory signals can either aggravate or ameliorate the disease depending on the stage of the disease, the cell-types involved and the signal transduction cascades initiated. This review focuses on the diverse roles of the most established co-stimulatory molecules of the B7 and Tumor Necrosis Factor Receptor (TNFR) families, ie the CD28/CTLA4-CD80/CD86 and CD40L/CD40 dyads in the pathogenesis of atherosclerosis and obesity. In addition, we will explore their potential as therapeutic targets in both atherosclerosis and obesity.

Negative regulation of NLRP3 inflammasome by SIRT1 in vascular endothelial cells

NLRP3 inflammasome not only functions as a critical effector in innate immunity, but also triggers the production of proinflammatory cytokines involved in inflammation-associated diseases. Sirtuin 1 (SIRT1) plays an important role in the regulation of cellular inflammation. However, whether the activation of NLRP3 inflammasome is regulated by SIRT1 remains unknown. In this study, we investigated the regulatory effect of SIRT1 on NLRP3 inflammasome and the underlying mechanisms. We found that lipopolysaccharide (LPS) and adenosine triphosphate (ATP)-induced the activation of NLRP3 inflammasome in human umbilical vein endothelial cells (HUVECs). Activation of SIRT1 inhibited NLRP3 inflammasome activation and subsequent caspase-1 cleavage as well as interleukin (IL)-1β secretion, whereas SIRT1 knockdown obviously enhanced the activation of NLRP3 inflammasome in HUVECs. Importantly, gene silencing of SIRT1 abrogated the inhibitory effect of SIRT1 activator on NLRP3 inflammasome formation and IL-1β production in HUVECs stimulated with LPS plus ATP. Further study indicated that cluster of differentiation 40 (CD40) may be involved in the regulation of NLRP3 inflammasome by SIRT1. In vivo studies indicated that implantation of the periarterial carotid collar increased the arterial expression levels of CD40 and CD40 Ligand (CD40L), but inhibited arterial SIRT1 expression in the rabbits. Moreover, treatment with SIRT1 activator decreased CD40 and CD40L levels in collared arteries. Meanwhile, serum IL-1β level, the marker of inflammasome activation, was also inhibited by SIRT1 activation. Taken together, these findings revealed a novel regulatory mechanism of NLRP3 inflammasome by SIRT1, which may be related to suppression of CD40.

Distinct Differences on Neointima Formation in Immunodeficient and Humanized Mice after Carotid or Femoral Arterial Injury

Percutaneous coronary intervention is widely adopted to treat patients with coronary artery disease. However, restenosis remains an unsolved clinical problem after vascular interventions. The role of the systemic and local immune response in the development of restenosis is not fully understood. Hence, the aim of the current study was to investigate the role of the human immune system on subsequent neointima formation elicited by vascular injury in a humanized mouse model. Immunodeficient NOD.Cg-Prkdc^scidIL2rg^tm1Wjl(NSG) mice were reconstituted with human (h)PBMCs immediately after both carotid wire and femoral cuff injury were induced in order to identify how differences in the severity of injury influenced endothelial regeneration, neointima formation, and homing of human inflammatory and progenitor cells. In contrast to non-reconstituted mice, hPBMC reconstitution reduced neointima formation after femoral cuff injury whereas hPBMCs promoted neointima formation after carotid wire injury 4 weeks after induction of injury. Neointimal endothelium and smooth muscle cells in the injured arteries were of mouse origin. Our results indicate that the immune system may differentially respond to arterial injury depending on the severity of injury, which may also be influenced by the intrinsic properties of the arteries themselves, resulting in either minimal or aggravated neointima formation.

New function of the myostatin/activin type I receptor (ALK4) as a mediator of muscle atrophy and muscle regeneration

Skeletal muscle fibrosis and impaired muscle regeneration are major contributors to muscle wasting in Duchenne muscular dystrophy (DMD). Muscle growth is negatively regulated by myostatin (MSTN) and activins. Blockage of these pathways may improve muscle quality and function in DMD. Antisense oligonucleotides (AONs) were designed specifically to block the function of ALK4, a key receptor for the MSTN/activin pathway in skeletal muscle. AON-induced exon skipping resulted in specific Alk4 down-regulation, inhibition of MSTN activity, and increased myoblast differentiation in vitro. Unexpectedly, a marked decrease in muscle mass (10%) was found after Alk4 AON treatment in mdx mice. In line with in vitro results, muscle regeneration was stimulated, and muscle fiber size decreased markedly. Notably, when Alk4 was down-regulated in adult wild-type mice, muscle mass decreased even more. RNAseq analysis revealed dysregulated metabolic functions and signs of muscle atrophy. We conclude that ALK4 inhibition increases myogenesis but also regulates the tight balance of protein synthesis and degradation. Therefore, caution must be used when developing therapies that interfere with MSTN/activin pathways.—Pasteuning-Vuhman, S., Boertje-van der Meulen, J. W., van Putten, M., Overzier, M., ten Dijke, P., Kiełbasa, S. M., Arindrarto, W., Wolterbeek, R., Lezhnina, K. V., Ozerov, I. V., Aliper, A. M., Hoogaars, W. M., Aartsma-Rus, A., Loomans, C. J. M. New function of the myostatin/activin type I receptor (ALK4) as a mediator of muscle atrophy and muscle regeneration.

CD40 in coronary artery disease: a matter of macrophages?

Coronary artery disease (CAD), also known as ischemic heart disease (IHD), is the leading cause of mortality in the western world, with developing countries showing a similar trend. With the increased understanding of the role of the immune system and inflammation in coronary artery disease, it was shown that macrophages play a major role in this disease. Costimulatory molecules are important regulators of inflammation, and especially, the CD40L-CD40 axis is of importance in the pathogenesis of cardiovascular disease. Although it was shown that CD40 can mediate macrophage function, its exact role in macrophage biology has not gained much attention in cardiovascular disease. Therefore, the goal of this review is to give an overview on the role of macrophage-specific CD40 in cardiovascular disease, with a focus on coronary artery disease. We will discuss the function of CD40 on the macrophage and its (proposed) role in the reduction of atherosclerosis, the reduction of neointima formation, and the stimulation of arteriogenesis.

TRAF3 Epigenetic Regulation Is Associated With Vascular Recurrence in Patients With Ischemic Stroke

Background and Purpose—

Clopidogrel is one of the most used antiplatelet drugs in patients with cardiovascular disease. However, 16% to 50% of patients have a high on-clopidogrel platelet reactivity and an increased risk of ischemic events. The pathogenesis of high on-treatment platelet reactivity in patients with stroke is only partially explained by genetic variations. This study aims to find differentially methylated sites across the genome associated with vascular recurrence in ischemic stroke patients treated with clopidogrel.

Methods—

From a cohort of 1900 patients with ischemic stroke, we selected 42 patients treated with clopidogrel, including 21 with a recurrent vascular event and 21 without vascular recurrence during the first year of follow-up. Over 480 000 DNA methylation sites were analyzed across the genome. Differentially methylated CpG sites were identified by nonparametric testing using R. Replication analysis was performed in a new cohort of 191 subjects and results were correlated with platelet reactivity in a subset of 90 subjects using light transmission aggregometry.

Results—

A total of 73 differentially methylated CpG sites ( P <1×10 −05 ) were identified; 3 of them were selected for further replication: cg03548645 ( P =1.42×10 −05 , TRAF3 ), cg09533145 ( P =7.81×10 −06 , ADAMTS2 ), and cg15107336 ( P =1.89×10 −05 , XRCC1 ). The cg03548645 CpG remained significant in the replication study ( P =0.034), a deep analysis of this region revealed another methylation site associated with vascular recurrence, P =0.037. Lower cg03548645 ( TRAF3 ) DNA methylation levels were correlated with an increased platelet aggregation (ρ=−0.29, P =0.0075).

Conclusions—

This study suggests for the first time that epigenetics may significantly contribute to the variability of clopidogrel response and recurrence of ischemic events in patients with stroke.

Survival analysis and microarray profiling identify Cd40 as a candidate for the Salmonella susceptibility locus, Ity5

The outcome of infection with Salmonella Typhimurium in mouse models of human typhoid fever is dependent upon a coordinated complex immune response. A panel of recombinant congenic strains (RCS) derived from reciprocal backcross of A/J and C57BL/6J mice was screened for their susceptibility to Salmonella infection and two susceptibility loci, Ity4 (Immunity to Typhimurium locus 4) and Ity5, were identified. We validated Ity5 in a genetic environment free of the impact of Ity4 using a cross between A/J and 129S6. Using a time-series analysis of genome-wide transcription during infection, comparing A/J with AcB60 mice having a C57BL/6J-derived Ity5 interval, we have identified the differential expression of the positional candidate gene Cd40, Cd40-associated signaling pathways, and the differential expression of numerous genes expressed in neutrophils. CD40 is known to coordinate T cell-dependent B-cell responses and myeloid cell activation. In fact, CD40 signaling is altered in A/J mice as seen by impaired IgM upregulation during infection, decreased Ig class switching, neutropenia, reduced granulocyte recruitment in response to infection and inflammation, and decreased ERK1/2 activity. These results suggest that altered CD40 signaling and granulocyte recruitment in response to infection are responsible for the Ity5-associated Salmonella susceptibility of A/J mice.

Regulation of atherosclerotic plaque inflammation

The immune reactions that regulate atherosclerotic plaque inflammation involve chemokines, lipid mediators and costimulatory molecules. Chemokines are a family of chemotactic cytokines that mediate immune cell recruitment and control cell homeostasis and activation of different immune cell types and subsets. Chemokine production and activation of chemokine receptors form a positive feedback mechanism to recruit monocytes, neutrophils and lymphocytes into the atherosclerotic plaque. In addition, chemokine signalling affects immune cell mobilization from the bone marrow. Targeting several of the chemokines and/or chemokine receptors reduces experimental atherosclerosis, whereas specific chemokine pathways appear to be involved in plaque regression. Leukotrienes are lipid mediators that are formed locally in atherosclerotic lesions from arachidonic acid. Leukotrienes mediate immune cell recruitment and activation within the plaque as well as smooth muscle cell proliferation and endothelial dysfunction. Antileukotrienes decrease experimental atherosclerosis, and recent observational data suggest beneficial clinical effects of leukotriene receptor antagonism in cardiovascular disease prevention. By contrast, other lipid mediators, such as lipoxins and metabolites of omega-3 fatty acids, have been associated with the resolution of inflammation. Costimulatory molecules play a central role in fine-tuning immunological reactions and mediate crosstalk between innate and adaptive immunity in atherosclerosis. Targeting these interactions is a promising approach for the treatment of atherosclerosis, but immunological side effects are still a concern. In summary, targeting chemokines, leukotriene receptors and costimulatory molecules could represent potential therapeutic strategies to control atherosclerotic plaque inflammation.

Prostaglandin E2-EP4 signaling persistently amplifies CD40-mediated induction of IL-23 p19 expression through canonical and non-canonical NF-κB pathways

While there is mounting evidence that interleukin (IL)-23-IL-17 axis plays a critical role in the pathogenesis of various autoimmune diseases, much remains to be elucidated on how IL-23 is induced in the pathological processes. IL-23 is a heterodimer composed of p19 and p40, the latter being shared with IL-12. We previously reported that prostaglandin (PG) E2 promotes CD40-mediated induction of Il23a (p19) expression through its E receptor subtype 4 (EP4) receptor in splenic dendritic cells (DCs). Here, we have analyzed signaling pathways regulating Il23a induction in the cross talk between EP4 and CD40 in bone marrow-derived DCs. We found that PGE2 synergistically induced Il23a transcription with CD40 signaling. An EP4 agonist, but not agonists of EP1, EP2, or EP3, reproduced this action. Stimulation of CD40 with an agonist antibody evoked biphasic induction of Il23a expression, with the early phase peaking at 1 h and the late phase peaking at 12 h and lasting up to 36 h after stimulation, whereas induction by lipopolysaccharide or tumor necrosis factor-α was transient. The early phase induction by CD40 stimulation was absent in DCs derived from Nfkb1-deficient mice, and the late phase induction was eliminated by RNA interference of nuclear factor-kappa B (NF-κB) p100 subunit. Further, cAMP response element-binding protein (CREB) depletion completely eliminated the induction of Il23a by CD40 stimulation. The addition of the EP4 agonist amplified the induction in both phases through the cAMP-protein kinase A (PKA) pathway. These results suggest that Il23a expression in DCs is synergistically triggered by the PG E2-EP4-cAMP-PKA pathway and canonical/non-canonical NF-κB pathways and CREB activated by CD40 stimulation.

CD137 expression is induced by Epstein-Barr virus infection through LMP1 in T or NK cells and mediates survival promoting signals

To clarify the mechanism for development of Epstein-Barr virus (EBV)-positive T- or NK-cell neoplasms, we focused on the costimulatory receptor CD137. We detected high expression of CD137 gene and its protein on EBV-positive T- or NK-cell lines as compared with EBV-negative cell lines. EBV-positive cells from EBV-positive T- or NK-cell lymphoproliferative disorders (EBV-T/NK-LPDs) patients also had significantly higher CD137 gene expression than control cells from healthy donors. In the presence of IL-2, whose concentration in the serum of EBV-T/NK-LPDs was higher than that of healthy donors, CD137 protein expression was upregulated in the patients' cells whereas not in control cells from healthy donors. In vitro EBV infection of MOLT4 cells resulted in induction of endogenous CD137 expression. Transient expression of LMP1, which was enhanced by IL-2 in EBV-T/NK-LPDs cells, induced endogenous CD137 gene expression in T and NK-cell lines. In order to examine in vivo CD137 expression, we used EBV-T/NK-LPDs xenograft models generated by intravenous injection of patients' cells. We identified EBV-positive and CD8-positive T cells, as well as CD137 ligand-positive cells, in their tissue lesions. In addition, we detected CD137 expression on the EBV infected cells from the lesions of the models by immune-fluorescent staining. Finally, CD137 stimulation suppressed etoposide-induced cell death not only in the EBV-positive T- or NK-cell lines, but also in the patients' cells. These results indicate that upregulation of CD137 expression through LMP1 by EBV promotes cell survival in T or NK cells leading to development of EBV-positive T/NK-cell neoplasms.

Roles of the kinase TAK1 in CD40-mediated effects on vascular oxidative stress and neointima formation after vascular injury

Although TAK1 has been implicated in inflammation and oxidative stress, its roles in vascular smooth muscle cells (VSMCs) and in response to vascular injury have not been investigated. The present study aimed to investigate the role of TAK1 in modulating oxidative stress in VSMCs and its involvement in neointima formation after vascular injury. Double immunostaining reveals that vascular injury induces a robust phosphorylation of TAK1 (Thr187) in the medial VSMCs of injured arteries in wildtype mice, but this effect is blocked in CD40-deficient mice. Upregulation of TAK1 in VSMCs is functionally important, as it is critically involved in pro-oxidative and pro-inflammatory effects on VSMCs and eventual neointima formation. In vivo, pharmacological inhibition of TAK1 with 5Z-7-oxozeaenol blocked the injury-induced phosphorylation of both TAK1 (Thr187) and NF-kB/p65 (Ser536), associated with marked inhibition of superoxide production, 3-nitrotyrosine, and MCP-1 in the injured arteries. Cell culture experiments demonstrated that either siRNA knockdown or 5Z-7-oxozeaenol inhibition of TAK1 significantly attenuated NADPH oxidase activation and superoxide production induced by CD40L/CD40 stimulation. Co-immunoprecipitation experiments indicate that blockade of TAK1 disrupted the CD40L-induced complex formation of p22phox with p47phox, p67phox, or Nox4. Blockade of TAK1 also inhibited CD40L-induced NF-kB activation by modulating IKKα/β and NF-kB p65 phosphorylation and this was related to reduced expression of proinflammatory genes (IL-6, MCP-1 and ICAM-1) in VSMCs. Lastly, treatment with 5Z-7-oxozeaenol attenuated neointimal formation in wire-injured femoral arteries. Our findings demonstrate previously uncharacterized roles of TAK1 in vascular oxidative stress and the contribution to neointima formation after vascular injury.

Costimulatory molecule CD40 is essential for myelin protein 0 peptide 106-125-induced experimental autoimmune neuritis in mice

Myelin protein 0 peptide 106-125-induced murine experimental autoimmune neuritis (EAN) is a CD4-positive T cell-mediated monophasic axonal inflammatory neuropathy; interferon-γ is the key proinflammatory mediator. Experimental autoimmune neuritis is well suited for elucidating pathogenetic mechanisms underlying human acute axonal Guillain-Barré syndrome. Here, the functional role of the costimulatory molecule CD40 was defined by characterization of EAN in CD40-deficient mice. In contrast to immunized C57BL/6 mice, CD40-deficient mice were resistant to EAN owing to impaired priming of CD4-positive T-effector cells. To determine whether CD40 is a suitable candidate for the treatment of EAN, we administered monoclonal anti-CD40 antibody either before immunization or upon onset of neurologic signs. Prophylactic anti-CD40 treatment completely abolished CD4-positive T-cell priming. Therapeutic application of anti-CD40 prevented full activation of CD4-positive T cells that were in the process of priming and suppressed production of interferon-γ in peripheral lymph nodes, spleen, and serum, and of interleukin-6, interleukin-12p40, intercellular adhesion molecule-1, and vascular cell adhesion molecule-1, which are associated with activation of the nuclear factor-κB signaling pathway. This resulted in enhanced recovery by early generation of CD25-positive, Foxp3-positive, CD4-positive regulatory T cells. Thus, these experiments highlight the crucial role of CD40 as an important costimulatory molecule in EAN and suggest that it has potential as a therapeutic target in human neuritis.

Expression and role of icam-1 in the occurrence and development of hepatocellular carcinoma

Intercellular adhesion molecule-1 (ICAM-1) is a member of the immunoglobulin superfamily, its main function being to participate in recognition and adhesion between cells. ICAM-1 is considered closely related to occurrence, development, metastasis and invasion process of hepatocellular carcinoma (HCC). A variety of inflammatory cytokines and stimulus affect its expression through the nuclear factor-kappa B (NF-κB) signal transduction pathway. In the initial stage of inflammation, hepatocirrhosis and tumor development, ICAM-1 is expressed differently, and has varied effects on different cells to promote occurrence of malignancy and metastasis. ICAM-1 has diagnostic significance for AFP-negative or suspected HCC, and may be a prognositic significance. It is thus widely used in studies as a biomarker which reflects cancer cells metastasis as well as curative effect of drugs. Many new treatments of HCC may be based on the effects of ICAM-1 on different levels of function.

Lymphocytic tumor necrosis factor receptor superfamily co-stimulatory molecules in the pathogenesis of atherosclerosis

PURPOSE OF REVIEW

The role of lymphocytes in the chronic inflammatory disease atherosclerosis has emerged over the past decade. Co-stimulatory molecules of the heterogeneous tumor necrosis factor receptor superfamily play a pivotal role in lymphocyte activation, proliferation and differentiation. Here we describe the immune modulatory properties and mechanisms of four tumor necrosis factor receptor superfamily members in atherosclerosis.

RECENT FINDINGS

CD40/CD40L, OX40L/OX40, CD70/CD27 and CD137/CD137L are present in human atherosclerotic plaques and have shown strong immune modulatory functions in atherosclerosis, resulting in either atherogenic or atheroprotective effects in mouse models of atherosclerosis.

SUMMARY

Insight into the immune modulatory mechanisms of co-stimulatory interactions in atherosclerosis can contribute to clinical exploitation of these interactions in the treatment of cardiovascular disease.

Soluble CD40 ligand stimulates CD40-dependent activation of the β2 integrin Mac-1 and protein kinase C zeda (PKCζ) in neutrophils: implications for neutrophil-platelet interactions and neutrophil oxidative burst

Recent work has revealed an essential involvement of soluble CD40L (sCD40L) in inflammation and vascular disease. Activated platelets are the major source of sCD40L, which has been implicated in platelet and leukocyte activation, although its exact functional impact on leukocyte-platelet interactions and the underlying mechanisms remain undefined. We aimed to determine the impact and the mechanisms of sCD40L on neutrophils. We studied neutrophil interactions with activated, surface-adherent platelets as a model for leukocyte recruitment to the sites of injury. Our data show that CD40L contributes to neutrophil firm adhesion to and transmigration across activated surface-adherent platelets, possibly through two potential mechanisms. One involves the direct interaction of ligand-receptor (CD40L-CD40), i.e., platelet surface CD40L interaction with neutrophil CD40; another involves an indirect mechanism, i.e. soluble CD40L stimulates activation of the leukocyte-specific β2 integrin Mac-1 in neutrophils and thereby further promotes neutrophil adhesion and migration. Activation of the integrin Mac-1 is known to be critical for mediating neutrophil adhesion and migration. sCD40L activated Mac-1 in neutrophils and enhanced neutrophil-platelet interactions in wild-type neutrophils, but failed to elicit such responses in CD40-deficient neutrophils. Furthermore, our data show that the protein kinase C zeta (PKCζ) is critically required for sCD40L-induced Mac-1 activation and neutrophil adhesive function. sCD40L strongly stimulated the focal clustering of Mac-1 (CD11b) and the colocalization of Mac-1 with PKCζ in wild-type neutrophils, but had minimal effect in CD40-deficient neutrophils. Blocking PKCζ completely inhibited sCD40L-induced neutrophil firm adhesion. Moreover, sCD40L strongly stimulates neutrophil oxidative burst via CD40-dependent activation of PI3K/NF-KB, but independent of Mac-1 and PKCζ. These findings may contribute to a better understanding of the underlying mechanisms by which sCD40L/CD40 pathway contributes to inflammation and vascular diseases.

CD40 activation induces NREM sleep and modulates genes associated with sleep homeostasis

The T-cell derived cytokine CD40 ligand is overexpressed in patients with autoimmune diseases. Through activation of its receptor, CD40 ligand leads to a tumor necrosis factor (TNF) receptor 1 (TNFR1) dependent impairment of locomotor activity in mice. Here we report that this effect is explained through a promotion of sleep, which was specific to non-rapid eye movement (NREM) sleep while REM sleep was suppressed. The increase in NREM sleep was accompanied by a decrease in EEG delta power during NREM sleep and by a decrease in the expression of transcripts in the cerebral cortex known to be associated with homeostatic sleep drive, such as Homer1a, Early growth response 2, Neuronal pentraxin 2, and Fos-like antigen 2. The effect of CD40 activation was mimicked by peripheral TNF injection and prevented by the TNF blocker etanercept. Our study indicates that sleep-wake dysregulation in autoimmune diseases may result from CD40 induced TNF:TNFR1 mediated alterations of molecular pathways, which regulate sleep-wake behavior.