CD40 expression by human bronchial epithelial cells

A spatially resolved atlas of the human lung characterizes a gland-associated immune niche

Single-cell transcriptomics has allowed unprecedented resolution of cell types/states in the human lung, but their spatial context is less well defined. To (re)define tissue architecture of lung and airways, we profiled five proximal-to-distal locations of healthy human lungs in depth using multi-omic single cell/nuclei and spatial transcriptomics (queryable at lungcellatlas.org ). Using computational data integration and analysis, we extend beyond the suspension cell paradigm and discover macro and micro-anatomical tissue compartments including previously unannotated cell types in the epithelial, vascular, stromal and nerve bundle micro-environments. We identify and implicate peribronchial fibroblasts in lung disease. Importantly, we discover and validate a survival niche for IgA plasma cells in the airway submucosal glands (SMG). We show that gland epithelial cells recruit B cells and IgA plasma cells, and promote longevity and antibody secretion locally through expression of CCL28, APRIL and IL-6. This new 'gland-associated immune niche' has implications for respiratory health.

Expression of CD40 Correlates Negatively with Overall and Progression-Free Survival of Low- and High-Grade Gliomas

BACKGROUND

Low-grade gliomas (LGGs) are known to progress to glioblastoma (GBM), decreasing the chances of survival. The tumor necrosis factor receptor CD40 and its ligand CD40L have shown value as biomarkers for GBM. The present study evaluated the role of CD40/CD40L in LGG and GBM in differentiating isocitrate dehydrogenase (IDH) wild-type and IDH-mutant GBM.

METHODS

The present study was based on patient-derived samples (74 grade II gliomas, 36 grade III gliomas, and 40 cases of GBM) and expression analysis using real-time polymerase chain reaction. Open-access data from The Cancer Genome Atlas (TCGA) and the strong cohorts of TCGA data sets "brain lower grade glioma" and "glioblastoma" were used to run the analysis on mRNA expression as a validation data set.

RESULTS

We found that patients with LGG and CD40 overexpression experienced shorter progression-free survival (43 vs. 29 months; hazard ratio, 0.5715; P = 0.0262) and overall survival (116 vs. 54 months; hazard ratio, 0.3431; P < 0.0001). Consistently, relapsed grade II glioma showed greater CD40 expression compared with primary grade II glioma (P = 0.0028). Just as with LGG, CD40 was a negative marker for overall survival in GBM (12 vs. 10 months; hazard ratio, 0.5178; P = 0.0491). In this context, we found greater CD40 expression in IDH wild-type GBM than in IDH-mutant GBM. The data obtained from TCGA supported our findings, with similar results for PFS and OS in LGG and GBM. CD40L expression showed no correlation with the survival data.

CONCLUSION

High CD40 expression showed a significant correlation with poor outcomes for both LGG and GBM and was overexpressed in IDH wild-type GBM.

CD30/CD30 Ligand and CD40/CD40 Ligand in Malignant Lymphoid Disorders

CD30 and CD40 are members of the tumor necrosis factor (TNF) receptor family. These two receptors have pleiotropic biologic functions including induction of apoptosis and enhancing cell survival. This review will discuss the pattern of expression of these receptors in malignant lymphoid disorders and their prospective ligands. Understanding issues related to these two ligands and their receptors in lymphoid malignancies may help to improve the classification of these diseases and could open the doors for new treatment strategies.

ICON: the early diagnosis of congenital immunodeficiencies

Primary immunodeficiencies are intrinsic defects in the immune system that result in a predisposition to infection and are frequently accompanied by a propensity to autoimmunity and/or immunedysregulation. Primary immunodeficiencies can be divided into innate immunodeficiencies, phagocytic deficiencies, complement deficiencies, disorders of T cells and B cells (combined immunodeficiencies), antibody deficiencies and immunodeficiencies associated with syndromes. Diseases of immune dysregulation and autoinflammatory disorder are many times also included although the immunodeficiency in these disorders are often secondary to the autoimmunity or immune dysregulation and/or secondary immunosuppression used to control these disorders. Congenital primary immunodeficiencies typically manifest early in life although delayed onset are increasingly recognized. The early diagnosis of congenital immunodeficiencies is essential for optimal management and improved outcomes. In this International Consensus (ICON) document, we provide the salient features of the most common congenital immunodeficiencies.

CD40 signaling to the rescue: A CD8 exhaustion perspective in chronic infectious diseases

Chronic infectious diseases such as HIV, HBV, and HCV, among others, cause severe morbidity and mortality globally. Progressive decline in CD8 functionality, survival, and proliferative potential-a phenomenon referred to as CD8 exhaustion-is believed to be responsible for poor pathogen control in chronic infectious diseases. While the role of negative inhibitory receptors such as PD-1 in augmenting CD8 exhaustion has been extensively studied, the role of positive costimulatory receptors remains poorly understood. In this review, we discuss how one such costimulatory pathway, CD40-CD40L, regulates CD8 dysfunction and rescue. While the significance of this pathway has been extensively investigated in models of autoimmunity, acute infectious diseases, and tumor models, the role played by CD40-CD40L in regulating CD8 exhaustion in chronic infectious diseases is just beginning to be understood. Considering that monotherapy with blocking antibodies targeting inhibitory PD-1-PD-L1 pathway is only partially effective at ameliorating CD8 exhaustion and that humanized CD40 agonist antibodies are currently available, a better understanding of the role of the CD40-CD40L pathway in chronic infectious diseases will pave the way for the development of more robust immunotherapeutic and prophylactic vaccination strategies.

Anti-CD40 monoclonal antibody

Normal, bi-directional interactions between CD 40 and its natural ligand CD 154 (CD 40 ligand) are central to the generation of both T cell-dependent, humoral immune responses and cytotoxic T-cell responses. CD 40 is expressed on a broad range of hematological and epithelial malignancies. The development of monoclonal antibodies directed against CD 40 allows effective targeting of malignant cells through multiple mechanisms that include the recruitment of immune effector mechanisms such as complement-dependent cytotoxicity and antibody-dependent cellular cytotoxicity, direct anti-proliferative effects on neoplastic cells and, importantly, by the activation of tumor-targeted cellular cytotoxicity. This review provides the background to the early clinical trial data that are now beginning to emerge for this potentially exciting new treatment approach.

Epithelial cells as immune effector cells: the role of CD40

Through the expression of inflammatory mediators and immune-related molecules, epithelial cells function as immune effector cells in a wide variety of tissues; the expression of the CD40 receptor on these cells contributes this role. Engagement of CD40 activates epithelial cells and results in their release of pro- and anti-inflammatory mediators as well as pro-fibrotic molecules. As such, epithelial CD40 has been implicated in the pathogenesis of inflammatory disorders, generation of self-tolerance, and rejection of allografts.

CD40 ligation protects bronchial epithelium against oxidant-induced caspase-independent cell death

CD40 and its ligand regulate pleiotropic biological responses, including cell proliferation, differentiation, and apoptosis. In many inflammatory lung diseases, tissue damage by environmental or endogenous oxidants plays a major role in disease pathogenesis. As the epithelial barrier is a major target for these oxidants, we postulated that CD40, the expression of which is increased in asthma, plays a role in the regulation of apoptosis of bronchial epithelial cells exposed to oxidants. Using 16HBE 14o- cells exposed to oxidant stress, we found that ligation of CD40 (induced by G28-5 monoclonal antibodies) enhanced cell survival and increased the number of cells in G2/M (interphase between DNA synthesis and mitosis) of the cell cycle. This was associated with NF-kappaB and activator protein-1 activation and increased expression of the inhibitor of apoptosis, c-IAP1. However, oxidant stress-induced apoptosis was found to be caspase- and calpain-independent implicating CD40 ligation as a regulator of caspase-independent cell death. This was confirmed by the demonstration that CD40 ligation prevented mitochondrial release and nuclear translocation of apoptosis inducing factor. In conclusion, we demonstrate a novel role for CD40 as a regulator of epithelial cell survival against oxidant stress. Furthermore, we have identified, for the first time, an endogenous inhibitory pathway of caspase-independent cell death.

Novel role of CD40 in Fas-dependent apoptosis of cultured salivary epithelial cells from patients with Sjögren's syndrome

OBJECTIVE

To determine the role of Fas and CD40 in the molecular mechanism of salivary epithelial cell death in Sjogren's syndrome (SS).

METHODS

The expression of Fas and CD40 in SS salivary epithelial cells was analyzed by flow cytometry. Induction of apoptosis with anti-Fas and/or anti-CD40 monoclonal antibodies (mAb) was examined by morphologic analysis, DNA fragmentation, and TUNEL assay. Expression of c-FLIP, Fas-associated phosphatase 1, FADD, Bcl-2, Bcl-x(L), and Bcl-x(S) was determined by Western blot analysis.

RESULTS

Expression of Fas and CD40 was significantly higher in SS salivary epithelial cells than in normal cells after interferon-gamma (IFNgamma) stimulation (P < 0.001 for both Fas and CD40). Although neither anti-Fas (CH11) nor anti-CD40 mAb alone could induce typical apoptosis, the two together and preincubation with IFNgamma efficiently induced apoptosis in SS salivary epithelial cells. This apoptosis was almost completely blocked by neutralizing anti-Fas mAb (ZB4), whereas an antagonistic mAb to CD40 (ch5D12) partially inhibited anti-Fas/anti-CD40-induced apoptosis. Also, c-FLIP, an important inhibitory molecule in the Fas death pathway, was strongly expressed in SS salivary epithelial cells, but its expression was down-regulated at the protein level by anti-CD40 mAb.

CONCLUSION

CD40 signals promote Fas-dependent death of SS salivary epithelial cells by down-regulating c-FLIP expression. The presence of c-FLIP in these cells may explain their resistance to undergoing apoptosis in response to either anti-Fas or anti-CD40 mAb, despite their surface expression of both proteins. These findings suggest that SS salivary epithelial cell death requires the cooperation of both Fas and CD40.

CD40 on adult human airway epithelial cells: expression and proinflammatory effects

CD40/CD40 ligand interaction is an important pathway for B and T cell cooperation and function; functional CD40 molecules have recently been found on nonhematopoietic cells. We detected CD40 in vivo on normal human respiratory epithelial cells and showed that its expression is increased on inflamed airway epithelium. Subsequently, we analyzed its expression and function on primary cultures of human airway epithelial cells. Our data show that CD40 is up-regulated by IFN-beta and IFN-gamma, its ligation increases the surface expression of CD54 and CD106 and it may stimulate the release of IL-6 and IL-8. The use of Janus kinase 3 (JAK3) and NF-kappaB inhibitors suggests that both basal and CD40-induced release of the two cytokines is JAK3-dependent. Using colocalization techniques, we revealed the existence of CD40/JAK3 and CD40/TNFR-associated factor 2 interplay. The extent of these interactions may be partial (2-40% of the cells) or massive (80-90% of the cells) in cultured cells. Stimulation via CD40 causes a significant increase in the number of cells expressing colocalization only in the cultures displaying low frequency of initial colocalization. Thus, airway epithelial cells, activated by CD40, may behave as effector cells of the inflammation process and should be considered priority targets for anti-inflammatory therapy. This work identifies CD40 and the correlated JAK3 signaling molecule as potential molecular targets to block the inflammatory functions of epithelial cells.

IFN regulatory factor-1 is required for the up-regulation of the CD40-NF-kappa B activator 1 axis during airway inflammation

Recent studies show that NF-kappa B activator 1 (Act1) functions as an important adapter molecule for CD40-mediated signaling in epithelial cells. To explore the physiological function of the CD40-Act1 axis, we studied the regulation of gene expression of CD40 and Act1 both in vivo and in cell culture models. Although CD40 and Act1 are up-regulated in mouse lung upon LPS stimulation, IL-1 plus IFN-alpha, -beta, or -gamma synergistically up-regulate both CD40 and Act1 gene expression in human epithelial A549 cells. Cycloheximide superinduces the Act1 mRNA, whereas actinomycin D completely abolishes the Act1 mRNA, indicating that the induction of Act1 mRNA is at the transcriptional level and does not require protein synthesis. Promoter sequence analyses identified putative IFN regulatory factor (IRF)-1, C/EBP-beta, and AP-1 transcription factor binding sites in the Act1 promoter. Although mutation of any of the three sites abolished the promoter activity, Abs against IRF-1 and C/EBP-beta, but not AP-1, blocked the formation of the DNA-binding complex induced by IL-1 plus IFN-beta stimulation, suggesting cooperative action between IRF-1 and C/EBP-beta in mediating Act1 promoter activity. Importantly, LPS-induced gene expression of CD40 and Act1 in the mouse lung is abolished in IRF-1(-/-) mice, indicating an essential role of transcription factor IRF-1 in the coordinated regulation of these two genes during airway inflammation. The induced expression of the CD40-Act1 axis by inflammatory cytokines in epithelial cells probably plays an important role in priming these cells for their response to CD40 ligand during airway inflammation.

Disseminated cryptosporidium infection in an infant with hyper-IgM syndrome caused by CD40 deficiency

We report the case of an infant with severe respiratory infections, chronic diarrhea, failure to thrive, and disseminated Cryptosporidium parvum infection. Laboratory investigations disclosed a diagnosis of hyper-IgM syndrome caused by CD40 deficiency.

CD40 on salivary gland epithelial cells: high constitutive expression by cultured cells from Sjögren's syndrome patients indicating their intrinsic activation

CD40 has been identified in an expanding list of haematopoietic and non-haematopoietic cells and has received an increased interest based on its role in a variety of cell-mediated responses and its potential to participate in the pathogenesis of chronic inflammatory disorders. Sjögren's syndrome (SS) is an autoimmune exocrinopathy, which is characterized by chronic lymphocytic infiltration of exocrine glands and aberrant activation of epithelial tissues. We studied the expression of CD40 protein in cultured non-neoplastic salivary gland epithelial cell (SGEC) lines as well as in minor SG biopsies obtained from 17 SS patients and 12 controls. Immunocytochemical and flow cytometric analyses had revealed the occurrence of constitutively expressed CD40 molecules on the surface of long-term cultured SGEC lines, which could be further induced by interferon-gamma (IFN-gamma) and IL-1beta cytokines, but not tumour necrosis factor-alpha (TNF-alpha), IL-4, IL-6, granulocyte-macrophage colony-stimulating factor (GM-CSF) or IFN-alpha. Triggering of SGEC through CD40 enhanced the surface expression of the adhesion molecule intercellular adhesion molecule-1 (ICAM-1)/CD54, but not MHC class I and class II (HLA-DR) molecules. Spontaneous CD40 expression was significantly higher in SGEC lines derived from SS patients, compared with controls (P < 0.001), which is suggestive of their intrinsically activated status. In SG biopsies, CD40 was constitutively expressed by lymphocytes, ductal epithelial cells and endothelial cells but not by other glandular cell types, such as acinar cells, myoepithelial cells and fibroblasts. In addition, CD40L staining was also detected in 30--50% of the infiltrating lymphocytes in the biopsies of SS patients. Our findings indicate the immunoregulatory potential of SGEC and lend further support to a model of intrinsic activation in salivary epithelia in SS, whereby these cells actively participate in the induction and maintenance of lymphocytic infiltrates of patients.

Proinflammatory and Th2-derived cytokines modulate CD40-mediated expression of inflammatory mediators in airway epithelia: implications for the role of epithelial CD40 in airway inflammation

Cytokines produced by activated macrophages and Th2 cells within the lung play a key role in asthma-associated airway inflammation. Additionally, recent studies suggest that the molecule CD40 modulates lung immune responses. Because airway epithelial cells can act as immune effector cells through the expression of inflammatory mediators, the epithelium is now considered important in the generation of asthma-associated inflammation. Therefore, the goal of the present study was to examine the effects of proinflammatory and Th2-derived cytokines on the function of CD40 in airway epithelia. The results show that airway epithelial cells express CD40 and that engagement of epithelial CD40 induces a significant increase in expression of the chemokines RANTES, monocyte chemoattractant protein (MCP-1), and IL-8 and the adhesion molecule ICAM-1. Cross-linking epithelial CD40 had no effect on expression of the adhesion molecule VCAM-1. The proinflammatory cytokines TNF-alpha and IL-1beta and the Th2-derived cytokines IL-4 and IL-13 modulated the positive effects of CD40 engagement on inflammatory mediator expression in airway epithelial cells. Importantly, CD40 ligation enhanced the sensitivity of airway epithelial cells to the effects of TNF-alpha and/or IL-1beta on expression of RANTES, MCP-1, IL-8, and VCAM-1. In contrast, neither IL-4 nor IL-13 modified the effects of CD40 engagement on the expression of RANTES, MCP-1, IL-8, or VCAM-1; however, both IL-4 and IL-13 attenuated the effects of CD40 cross-linking on ICAM-1 expression. Together, these findings suggest that interactions between CD40-responsive airway epithelial cells and CD40 ligand+ leukocytes, such as activated T cells, eosinophils, and mast cells, modulate asthma-associated airway inflammation.