CD40L and Its Receptors in Atherothrombosis-An Update

Role of β2 Integrins in Neutrophils and Sepsis

Sepsis remains medically challenging, with high morbidity and mortality. A novel intervention is urgently needed in the absence of specific, targeted therapy. Neutrophils act as double-edged swords in sepsis; they can help to eradicate microbes, but they also contribute to tissue injury. β2 integrins are critical adhesion molecules that regulate a number of neutrophil functions. β2 integrins consist of four members, namely, αLβ2, αMβ2, αXβ2, and αDβ2. Here, we review the role of each β2 integrin in neutrophils and sepsis and consider future direction for therapeutic intervention.

The CD40-CD40L Dyad as Immunotherapeutic Target in Cardiovascular Disease

Chronic inflammation drives the development of atherosclerosis. Despite optimal treatment of classical cardiovascular risk factors, a substantial portion of the population has elevated inflammatory biomarkers and develops atherosclerosis-related complications, indicating that a residual inflammatory risk drives atherosclerotic cardiovascular disease in these patients. Additional anti-inflammatory therapeutic strategies are therefore required. The co-stimulatory molecule CD40 and its ligand CD40L (CD154) have a central role in the regulation of the inflammatory response during the development of atherosclerosis by modulating the interaction between immune cells and between immune cells and non-immune cells. In this review, we discuss the role of the CD40-CD40L dyad in atherosclerosis, and we discuss recent studies on the therapeutic potential of novel CD40-CD40L targeting strategies in cardiovascular medicine.

A computational model for understanding the oligomerization mechanisms of TNF receptor superfamily

By recognizing members in the tumor necrosis factor (TNF) receptor superfamily, TNF ligand proteins function as extracellular cytokines to activate various signaling pathways involved in inflammation, proliferation, and apoptosis. Most ligands in TNF superfamily are trimeric and can simultaneously bind to three receptors on cell surfaces. It has been experimentally observed that the formation of these molecular complexes further triggers the oligomerization of TNF receptors, which in turn regulate the intracellular signaling processes by providing transient compartmentalization in the membrane proximal regions of cytoplasm. In order to decode the molecular mechanisms of oligomerization in TNF receptor superfamily, we developed a new computational method that can physically simulate the spatial-temporal process of binding between TNF ligands and their receptors. The simulations show that the TNF receptors can be organized into hexagonal oligomers. The formation of this spatial pattern is highly dependent not only on the molecular properties such as the affinities of trans and cis binding, but also on the cellular factors such as the concentration of TNF ligands in the extracellular area or the density of TNF receptors on cell surfaces. Moreover, our model suggests that if TNF receptors are pre-organized into dimers before ligand binding, these lateral interactions between receptor monomers can play a positive role in stabilizing the ligand-receptor interactions, as well as in regulating the kinetics of receptor oligomerization. Altogether, this method throws lights on the mechanisms of TNF ligand-receptor interactions in cellular environments.

Biomimetic nanoparticle technology for cardiovascular disease detection and treatment

Cardiovascular disease (CVD), which encompasses a number of conditions that can affect the heart and blood vessels, presents a major challenge for modern-day healthcare. Nearly one in three people has some form of CVD, with many suffering from multiple or intertwined conditions that can ultimately lead to traumatic events such as a heart attack or stroke. While the knowledge obtained in the past century regarding the cardiovascular system has paved the way for the development of life-prolonging drugs and treatment modalities, CVD remains one of the leading causes of death in developed countries. More recently, researchers have explored the application of nanotechnology to improve upon current clinical paradigms for the management of CVD. Nanoscale delivery systems have many advantages, including the ability to target diseased sites, improve drug bioavailability, and carry various functional payloads. In this review, we cover the different ways in which nanoparticle technology can be applied towards CVD diagnostics and treatments. The development of novel biomimetic platforms with enhanced functionalities is discussed in detail.

CD40L Priming of Platelets via NF-κB Activation is CD40- and TAK1-Dependent

Background

CD40 ligand (CD40L) is a thromboinflammatory molecule that predicts cardiovascular events. CD40L is a strong activator of nuclear factor kappa B (NF‐κB) in platelets that primes and enhances platelet activation in response to thrombotic stimuli. In addition to its classical receptor CD40, CD40L binds αIIbβ3, α5β1, and αMβ2 in various cell types. However, the function of the different CD40L receptors on platelets remains unexplored. The present study aims to identify the receptors of CD40L, involved in platelet NF‐κB activation, their downstream signaling and their implication in platelet aggregation.

Methods and Results

We showed that platelets express CD40, αIIbβ3, and α5β1 and release CD40L in response to sCD40L stimulation. sCD40L alone dose‐dependently induced platelet NF‐κB activation; this effect was absent in CD40^−/− mouse platelets and inhibited by the CD40 blockade, but was unaffected by the αIIbβ3 or α5β1 blockade in human platelets. sCD40L/CD40 axis activates transforming growth factor‐β‐activated kinase 1 upstream of NF‐κB. In functional studies, sCD40L alone did not affect platelet aggregation but potentiated the aggregation response in the presence of suboptimal doses of thrombin; this effect was abolished by CD40, transforming growth factor‐β‐activated kinase 1, and NF‐κB inhibitors.

Conclusions

CD40L primes platelets via signaling pathways involving CD40/transforming growth factor‐β‐activated kinase 1/NF‐κB, which predisposes platelets to enhanced activation and aggregation in response to thrombotic stimuli.

CD40 forward signalling is a physiological regulator of early sensory axon growth

Multiple members of the tumour necrosis factor superfamily (TNFSF) regulate the growth and branching of neural processes late in development, when neurons are establishing and refining connections. Here, we present the first evidence that a TNFSF member acts much earlier in development, when axons are growing to their targets. CD40L transiently enhanced axon growth from embryonic mouse DRG neurons cultured at this early stage. Early spinal nerves of embryos lacking the CD40L receptor (Cd40^−/− mice) were significantly shorter in vivo than those of Cd40^+/+ littermates. CD40L was synthesized in early DRG targets and was co-expressed with CD40 in early DRG neurons. Whereas CD40L enhanced early axon growth independently of neurotrophins, disruption of a CD40L/CD40 autocrine loop impaired early neurotrophin-promoted axon growth. In marked contrast to the widespread regulation of axon and dendrite growth by CD40L reverse signalling later in development, CD40-Fc, which activates reverse signalling, had no effect on early sensory axon growth. These results suggest that CD40 forward signalling is a novel physiological regulator of early axon growth that acts by target-derived and autocrine mechanisms.

Summary: CD40L, a novel physiological regulator of early sensory axon growth at the stage when sensory axons are growing to their targets, activates CD40 forward signalling by target-derived and autocrine mechanisms.

Association of soluble CD40L with short-term and long-term cardiovascular and all-cause mortality: The Ludwigshafen Risk and Cardiovascular Health (LURIC) study

BACKGROUND AND AIMS

The CD40^-CD40 Ligand (CD40L) system has an important role in vascular inflammation. For this reason, we assessed the association of soluble CD40L with cardiovascular and all-cause mortality in the Ludwigshafen Risk and Cardiovascular Health (LURIC) study.

METHODS

Plasma levels of sCD40L were determined in 2759 persons using an enzyme immunoassay. Cox proportional hazard regressions were performed to evaluate the association between plasma concentration of sCD40 ligand and short-term (12 months) and long-term (10 years) mortality. Subpopulation analyses were conducted in seven different risk groups. Cox regression models were adjusted for traditional risk factors.

RESULTS

The present study did not reveal significant association between sCD40L plasma levels and all-cause mortality, as well as cardiovascular mortality at one-year follow-up. In selected subgroups only, significant association between elevated sCD40L plasma levels and short-term all-cause and cardiovascular mortality could be observed. With regard to long-term all-cause and cardiovascular mortality analyses, no significant correlation with increased plasma levels of sCD40L could be detected, neither overall nor in any subgroup.

CONCLUSIONS

Soluble sCD40L is not associated with cardiovascular and all-cause mortality in this large cohort. Only in selected patient subgroups elevated levels of sCD40L correlate with short-term mortality but this correlation disappears in long-term analysis.

Simultaneous Depression of Immunological Synapse and Endothelial Injury is Associated with Organ Dysfunction in Community-Acquired Pneumonia

Rationale: A depressed expression of antigen presentation is, along with endothelial dysfunction, a recognized signature of severe community-acquired pneumonia (CAP). We aimed to evaluate the expression of a number of genes involved in the immunological synapse in non-critically ill CAP patients with or without organ dysfunction and to profile endothelial biomarkers such as proendothelin-1 (proET1) and proadrenomedullin (proADM). Methods: A nested study in a prospective cohort in CAP patients was performed. Expression levels of major histocompatibility complex class II DR alpha (HLA-DRA), CD40 ligand (CD40LG), CD3E, CD28, and inducible T-cell costimulator (ICOS) were quantified by using droplet digital polymerase chain reaction and endothelial biomarkers by immunofluorescence. Results: Ninety-four patients were included, 44.7% of whom had organ failure in one or more organs. A significant decrease in the expression of the five genes with increased levels of proadrenomedullin (proADM) and proendothelin-1 (proET1) was found in CAP with organ failure. The depressed expression of HLA-DRA (odds ratio (OR), 2.94), CD40LG (OR, 3.90), and CD28 (OR, 3.48) was independently associated with organ failure after adjustment for age, Charlson score, and severity. Conclusions. CAP with organ failure showed depressed expression of immunological synapse genes with increased levels of biomarkers denoting endothelial damage. Simultaneous profiling of immunological and endothelial signatures could help in the early identification of organ failure in CAP and in the implementation of personalized treatment.

Impact of B-Cell–Targeted Therapies on Cardiovascular Disease

Atherosclerosis is a lipid-driven chronic inflammatory disease that is modulated by many immune cell subsets, including B cells. Therefore, targeting the inflammatory component of cardiovascular disease represents a promising therapeutic strategy. In the past years, immunotherapy has revolutionized the treatment of autoimmunity and cancer. Many of these clinically used strategies target B cells. Given the multifaceted role of B cells in atherogenesis, it is conceivable that B-cell–directed therapies can modulate disease development. Here, we review clinically available B-cell–targeted therapies and the possible benefits or detrimental effects on cardiovascular disease.

Composition and structure of synaptic ectosomes exporting antigen receptor linked to functional CD40 ligand from helper T cells

Planar supported lipid bilayers (PSLB) presenting T cell receptor (TCR) ligands and ICAM-1 induce budding of extracellular microvesicles enriched in functional TCR, defined here as synaptic ectosomes (SE), from helper T cells. SE bind peptide-MHC directly exporting TCR into the synaptic cleft, but incorporation of other effectors is unknown. Here, we utilized bead supported lipid bilayers (BSLB) to capture SE from single immunological synapses (IS), determined SE composition by immunofluorescence flow cytometry and enriched SE for proteomic analysis by particle sorting. We demonstrate selective enrichment of CD40L and ICOS in SE in response to addition of CD40 and ICOSL, respectively, to SLB presenting TCR ligands and ICAM-1. SE are enriched in tetraspanins, BST-2, TCR signaling and ESCRT proteins. Super-resolution microscopy demonstrated that CD40L is present in microclusters within CD81 defined SE that are spatially segregated from TCR/ICOS/BST-2. CD40L+ SE retain the capacity to induce dendritic cell maturation and cytokine production.

Role of NF-κB in Platelet Function

Platelets are megakaryocyte-derived fragments lacking nuclei and prepped to maintain primary hemostasis by initiating blood clots on injured vascular endothelia. Pathologically, platelets undergo the same physiological processes of activation, secretion, and aggregation yet with such pronouncedness that they orchestrate and make headway the progression of atherothrombotic diseases not only through clot formation but also via forcing a pro-inflammatory state. Indeed, nuclear factor-κB (NF-κB) is largely implicated in atherosclerosis and its pathological complication in atherothrombotic diseases due to its transcriptional role in maintaining pro-survival and pro-inflammatory states in vascular and blood cells. On the other hand, we know little on the functions of platelet NF-κB, which seems to function in other non-genomic ways to modulate atherothrombosis. Therein, this review will resemble a rich portfolio for NF-κB in platelets, specifically showing its implications at the levels of platelet survival and function. We will also share the knowledge thus far on the effects of active ingredients on NF-κB in general, as an extrapolative method to highlight the potential therapeutic targeting of NF-κB in coronary diseases. Finally, we will unzip a new horizon on a possible extra-platelet role of platelet NF-κB, which will better expand our knowledge on the etiology and pathophysiology of atherothrombosis.

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.

Targeting the CD40-CD154 Signaling Pathway for Treatment of Autoimmune Arthritis

Full activation of T lymphocytes requires signals from both T cell receptors and costimulatory molecules. In addition to CD28, several T cell molecules could deliver costimulatory signals, including CD154, which primarily interacts with CD40 on B-cells. CD40 is a critical molecule regulating several B-cell functions, such as antibody production, germinal center formation and cellular proliferation. Upregulated expression of CD40 and CD154 occurs in immune effector cells and non-immune cells in different autoimmune diseases. In addition, therapeutic benefits have been observed by blocking the CD40-CD154 interaction in animals with collagen-induced arthritis. Given the therapeutic success of the biologics abatacept, which blocks CD28 costimulation, and rituximab, which deletes B cells in the treatment of autoimmune arthritis, the inhibition of the CD40-CD154 axis has two advantages, namely, attenuating CD154-mediated T cell costimulation and suppressing CD40-mediated B-cell stimulation. Furthermore, blockade of the CD40-CD154 interaction drives the conversion of CD4+ T cells to regulatory T cells that mediate immunosuppression. Currently, several biological products targeting the CD40-CD154 axis have been developed and are undergoing early phase clinical trials with encouraging success in several autoimmune disorders, including autoimmune arthritis. This review addresses the roles of the CD40-CD154 axis in the pathogenesis of autoimmune arthritis and its potential as a therapeutic target.

Analysis of Genetic Variation in CD40 and CD40L: Relationship with mRNA Relative Expression and Soluble Proteins in Acute Coronary Syndrome

Acute coronary syndrome (ACS) can be triggered by the presence of inflammatory factors which promote the activation of immune cells by costimulatory molecules such as CD40 and its ligand CD40L. Environmental and genetic factors are involved in the etiology of the ACS. The aim of this study was to explore the gene and protein expression associated with CD40 and CD40L genetic variants in ACS patients from the western Mexican population. A total of 620 individuals from western Mexico were recruited: 320 ACS patients and 300 individuals without a history of ischemic cardiopathy were evaluated. The genotype was determined using TaqMan SNP genotyping assays. CD40 and CD40L expressions at the mRNA level were quantified using TaqMan Gene Expression Assays. Soluble protein isoforms were measured by enzyme-linked immunosorbent assay. We did not find evidence of association between CD40 (rs1883832, rs4810485, and rs11086998) and CD40L (rs3092952 and rs3092920) genetic variants and susceptibility to ACS, although rs1883832 and rs4810485 were significantly associated with high sCD40 plasma levels. Plasma levels of sCD40L can be affected by gender and the clinical spectrum of acute coronary syndrome. Our results do not suggest a functional role of CD40 and CD40L genetic variants in ACS. However, they could reflect the inflammatory process and platelet activation in ACS patients, even when they are under pharmacological therapy. Due to the important roles of the CD40-CD40L system in the pathogenesis of ACS, longitudinal studies are required to determine if soluble levels of CD40 and CD40L could be clinically useful markers of a recurrent cardiovascular event after an ACS.

CD40 ligand deficiency: treatment strategies and novel therapeutic perspectives

INTRODUCTION

CD40 ligand (CD40L) deficiency or X-linked Hyper-IgM syndrome is a severe primary immunodeficiency caused by mutations in the CD40L gene. Despite currently available treatments, CD40L-deficient patients remain susceptible to life-threatening infections and have poor long term survival. Areas covered: Here, we discuss clinical and immunological characteristics of CD40L deficiency as well as current therapeutic strategies used for patient management. This review highlights that beyond B cell defects, patients' susceptibility to opportunistic pathogens might be due to impaired T cell and innate immune responses. In this context, we discuss how better knowledge of CD40L function and regulation may result in the development of new treatments. Expert opinion: Despite the introduction of hematopoietic stem-cell transplantation, immunoglobulin replacement, granulocyte colony-stimulating factor (G-CSF) administration, and prophylactic antibiotic therapies, life-threatening infections still cause high morbidity and mortality among CD40L-deficient patients. The reasons for this inadequate response to current therapies remains poorly understood, but recent reports suggest the involvement of CD40L-CD40 interaction in early stages of the innate immune system ontogeny. The development of novel gene therapeutic approaches and the use of redirected immunotherapies represent alternative treatment methods that could offer reduced morbidity and mortality rates for patients with CD40L deficiency.

Targeting the CD40-CD40L pathway in autoimmune diseases: Humoral immunity and beyond

CD40 is a TNF receptor superfamily member expressed on both immune and non-immune cells. Interactions between B cell-expressed CD40 and its binding partner, CD40L, predominantly expressed on activated CD4+ T cells, play a critical role in promoting germinal center formation and the production of class-switched antibodies. Non-hematopoietic cells expressing CD40 can also engage CD40L and trigger a pro-inflammatory response. This article will highlight what is known about the biology of the CD40-CD40L axis in humans and describe the potential contribution of CD40 signaling on both hematopoietic and non-hematopoietic cells to autoimmune disease pathogenesis. Additionally, novel therapeutic approaches to target this pathway, currently being evaluated in clinical trials, are discussed.

2016 Jeffrey M. Hoeg Award Lecture

Innate and adaptive immune effector mechanisms, in conjunction with hyperlipidemia, are important drivers of atherosclerosis. The interaction between the different immune cells and the secretion of cytokines and chemokines determine the progression of atherosclerosis. The activation or dampening of the immune response is tightly controlled by immune checkpoints. Costimulatory and coinhibitory immune checkpoints represent potential targets for immune modulatory therapies for atherosclerosis. This review will discuss the current knowledge on immune checkpoints in atherosclerosis and the clinical potential of immune checkpoint targeted therapy for atherosclerosis.

T Cells in Atherosclerosis in Ldlr-/- and Apoe-/- Mice

Atherosclerosis is the underlying basis for most cardiovascular diseases. It is a chronic inflammation affecting the arterial intima and is promoted by hypercholesterolemia. Cells of both the innate and adaptive immune systems contribute to this inflammation with macrophages and T cells being the most abundant immune cells in the atherosclerotic plaques. In this review, we discuss the studies that examined the role of T cells and T cell subsets in Apoe-/- and Ldlr-/- murine models of atherosclerosis. While there is a general consensus that Th1 cells are pro-atherogenic and regulatory T cells are atheroprotective, the role of other subsets is more ambiguous. In addition, the results in the two models of atherosclerosis do not always yield similar results. Additional studies in the two murine models using cell specific gene manipulations are needed.

Biochemical markers of hypertension, prehypertension

OBJECTIVE

There are insufficient researches aimed at evaluating biochemical markers of mechanisms of formation of AH and lesion of target organs in hypertension and prehypertension. The aim of that research was to study the level of endothelial dysfunction markers and damage to the cardiovascular system in hypertension and prehypertension.

PATIENTS AND METHODS

A cross-sectional study was performed among 938 people aged 18 to 65 years. All respondents were surveyed, blood pressure measured, for glucose, cholesterol, interleukin-6, sFAS, LIGHT, hFABP, NT-ProBNP and an Endocan concentrations were tested. Depending on the level of blood pressure participants were splitted into groups with normotension, prehypertension and hypertension.

RESULTS

Comparing the markers of inflammation, apoptosis and target organ damage in the prehypertensive group, the level of the LIGHT protein was Me=265.2pg/ml (Q₂₅-Q₇₅: 197.7-444.3), in the control group - Me=251.1pg/ml (Q₂₅-Q₇₅: 176.6-376.6), the Endocan level was Me=660.6pg/ml (Q₂₅-Q₇₅: 419.6-867.4) and in the control group Me=587.5pg/ml (Q₂₅-Q₇₅: 401.9-838.1). In the AH group, the level of the LIGHT Me=273.1pg/ml (Q₂₅-Q₇₅: 195.1-455.2), Endocan Me=668.2pg/ml (Q₂₅-Q₇₅: 434.8-977.3), heart-type fatty-acid-binding protein Me=2233.1pg/ml (Q₂₅-Q₇₅: 1518.4-3391.1) exceeded the control group.

CONCLUSION

Thus, the development of prehypertension and hypertension is characterized by an increase in the activity of biochemical markers of endothelial dysfunction and damage to target organs, more expressed in the presence of hypertension.

Distinct Housing Conditions Reveal a Major Impact of Adaptive Immunity on the Course of Obesity-Induced Type 2 Diabetes

Obesity is associated with adipose tissue inflammation, insulin resistance, and the development of type 2 diabetes (T2D). However, our knowledge is mostly based on conventional murine models and promising preclinical studies rarely translated into successful therapies. There is a growing awareness of the limitations of studies in laboratory mice, housed in abnormally hygienic specific pathogen-free (SPF) conditions, as relevant aspects of the human immune system remain unappreciated. Here, we assessed the impact of housing conditions on adaptive immunity and metabolic disease processes during high-fat diet (HFD). We therefore compared diet-induced obesity in SPF mice with those housed in non-SPF, so-called "antigen exposed" (AE) conditions. Surprisingly, AE mice fed a HFD maintained increased insulin levels to compensate for insulin resistance, which was reflected in islet hyperplasia and improved glucose tolerance compared to SPF mice. By contrast, we observed higher proportions of effector/memory T cell subsets in blood and liver of HFD AE mice accompanied by the development of non-alcoholic steatohepatitis-like liver pathology. Thus, our data demonstrate the impact of housing conditions on metabolic alterations. Studies in AE mice, in which physiological microbial exposure was restored, could provide a tool for revealing therapeutic targets for immune-based interventions for T2D patients.

Single Nucleotide Polymorphisms in CD40L Predict Endothelial Complications and Mortality After Allogeneic Stem-Cell Transplantation

Purpose

Endothelial vulnerability is a potential risk factor for complications after allogeneic stem-cell transplantation (alloSCT). The CD40/CD40 ligand (CD40L) axis contributes to inflammatory diseases and is upregulated in endothelial cells upon activation, suggesting a role in alloSCT biology. Here, we studied single nucleotide polymorphisms (SNPs) in the CD40L gene in recipients of alloSCT.

Patients and Methods

Three CD40L SNPs (rs3092920, rs3092952, rs3092936) were analyzed for association with transplant-associated thrombotic microangiopathy, overall nonrelapse mortality (NRM), and NRM after acute graft-versus-host disease in 294 recipients of alloSCT without statin-based endothelial prophylaxis (SEP). The significant genotype was then put into perspective with established thrombomodulin ( THBD) gene polymorphisms. Findings were validated in an independent cohort without SEP and in an additional 344 patients who received SEP.

Results

The rs3092936 CC/CT genotype was associated with an increased risk of transplant-associated thrombotic microangiopathy ( P = .001), overall NRM ( P = .03), and NRM after acute graft-versus-host disease ( P = .01). The rs3092936 CC/CT genotype was largely mutually exclusive of high-risk THBD SNPs. Both CD40L and THBD SNPs predicted adverse overall survival (OS) and overall NRM to a similar extent in training cohort (OS, P = .04; NRM, P < .001) and validation cohort (OS, P = .01; NRM, P = .001) without SEP. In contrast, SEP completely abolished the influence of the high-risk CD40L and THBD SNPs ( P = .40).

Conclusion

An increased risk of endothelial complications can be predicted before alloSCT by genetic markers in the recipient’s genome. The normalization of mortality risks in patients treated with SEP suggests a way of overcoming the negative effect of high-risk genotypes and warrants further clinical validation.

Ginkgolide C Alleviates Myocardial Ischemia/Reperfusion-Induced Inflammatory Injury via Inhibition of CD40-NF-κB Pathway

Increasing evidence shows that inflammation plays a vital role in the occurrence and development of ischemia/reperfusion (I/R). Suppression of excessive inflammation can ameliorate impaired cardiac function, which shows therapeutic potential for clinical treatment of myocardial ischemia/reperfusion (MI/R) diseases. In this study, we investigated whether Ginkgolide C (GC), a potent anti-inflammatory flavone, extenuated MI/R injury through inhibition of inflammation. In vivo, rats with the occlusion of the left anterior descending (LAD) coronary artery were applied to mimic MI/R injury. In vitro, primary cultured neonatal ventricular myocytes exposed to hypoxia/reoxygenation (H/R) were applied to further discuss the anti-H/R injury property of GC. The results revealed that GC significantly improved the symptoms of MI/R injury, as evidenced by reducing infarct size, preventing myofibrillar degeneration and reversing the mitochondria dysfunction. Moreover, histological analysis and Myeloperoxidase (MPO) activity measurement showed that GC remarkably suppressed Polymorphonuclears (PMNs) infiltration and ameliorated the histopathological damage. Furthermore, GC pretreatment was shown to improve H/R-induced ventricular myocytes viability and enhance tolerance of inflammatory insult, as evidenced by suppressing expression of CD40, translocation of NF-κB p65 subunit, phosphorylation of IκB-α, as well as the activity of IKK-β. In addition, downstream inflammatory cytokines modulated by NF-κB signaling were effectively down-regulated both in vivo and in vitro, as determined by immunohistochemistry and ELISA. In conclusion, these results indicate that GC possesses a beneficial effect against MI/R injury via inflammation inhibition that may involve suppression of CD40-NF-κB signal pathway and downstream inflammatory cytokines expression, which may offer an alternative medication for MI/R diseases.

Distinct CD40L receptors mediate inflammasome activation and secretion of IL-1β and MCP-1 in cultured human retinal pigment epithelial cells

CD40L signaling occurs in several diseases with inflammatory components, including ocular and retinal diseases. However, it has never been evaluated as a pathogenic mechanism in age-related macular degeneration (AMD) or as an inducer of inflammasome formation in any cell type. mRNA and protein levels of CD40, IL-1β, NALP1, NALP3, caspase-1, and caspase-5 were determined by RT-PCR, qPCR, and Western blot. CD40L receptor (CD40, α5β1, and CD11b) expression was determined by Western and immunofluorescent staining. IL-1β, IL-18, and MCP-1 secretions were determined by ELISA. NALP1 and NALP3 inflammasome formation were determined by Co-IP. Experiments were conducted on primary human retinal pigment epithelial (hRPE) cells from four different donors. Human umbilical vein endothelial (HUVEC) and monocytic leukemia (THP-1) cells demonstrated the general applicability of our findings. In hRPE cells, CD40L-induced NALP1 and NALP3 inflammasome activation, cleavage of caspase-1 and caspase-5, and IL-1β and IL-18 secretion. Interestingly, neutralizing CD11b and α5β1 antibodies, but not CD40, reduced CD40L-induced IL-1β secretion in hRPE cells. Similarly, CD40L treatment also induced HUVEC and THP-1 cells to secret IL-1β through CD11b and α5β1. Additionally, the CD40L-induced IL-1β secretion acted in an autocrine/paracrine manner to feed back and induce hRPE cells to secrete MCP-1. This study is the first to show that CD40L induces inflammasome activation in any cell type, including hRPE cells, and that this induction is through CD11b and α5β1 cell-surface receptors. These mechanisms likely play an important role in many retinal and non-retinal diseases and provide compelling drug targets that may help reduce pro-inflammatory processes.

A ligand-specific blockade of the integrin Mac-1 selectively targets pathologic inflammation while maintaining protective host-defense

Integrin-based therapeutics have garnered considerable interest in the medical treatment of inflammation. Integrins mediate the fast recruitment of monocytes and neutrophils to the site of inflammation, but are also required for host defense, limiting their therapeutic use. Here, we report a novel monoclonal antibody, anti-M7, that specifically blocks the interaction of the integrin Mac-1 with its pro-inflammatory ligand CD40L, while not interfering with alternative ligands. Anti-M7 selectively reduces leukocyte recruitment in vitro and in vivo. In contrast, conventional anti-Mac-1 therapy is not specific and blocks a broad repertoire of integrin functionality, inhibits phagocytosis, promotes apoptosis, and fuels a cytokine storm in vivo. Whereas conventional anti-integrin therapy potentiates bacterial sepsis, bacteremia, and mortality, a ligand-specific intervention with anti-M7 is protective. These findings deepen our understanding of ligand-specific integrin functions and open a path for a new field of ligand-targeted anti-integrin therapy to prevent inflammatory conditions.