Involvement of APRIL in Helicobacter pylori-related gastric cancer.

BACKGROUND/AIMS: A proliferation-inducing ligand (APRIL, also known as TNFSF13, CD256) is a member of the tumor necrosis factor (TNF) superfamily and involved in a diverse set of diseases. In this work, we explored the potential associations and underlying mechanism in patients suffered from gastric cancer between the expression of APRIL and H. pylori infection. METHODS: We analyzed APRIL expression levels in 200 GC tissue samples by immunohistochemistry staining. H. pylori infection was detected by modified Giemsa staining. The biological effects of APRIL on human GC cells in vitro and in vivo were tested by CCK-8 assay, colony formation, flow cytometry detection, transwell migration assay, matrigel invasion assay, and tumor xenograft assay in animals. RESULTS: APRIL reactivity was positively correlated with H. pylori infection in vitro and vivo. It turned out that the decrease of miR-145 expression was dose-dependent and time-dependent on H. pylori infection and in consistent with APRIL expression. MiR-145 significantly attenuated the effect of H. pylori infection on APRIL gene expression in SGC7901 and BGC823 cell lines. Furthermore, APRIL overexpression promoted the proliferation, migration, invasion, and transfer of GC cells and decreased apoptosis, while APRIL knockdown suppressed these effects. We confirmed that APRIL activated the canonical NF-κB pathway through phosphorylation of AKT. CONCLUSION: The expression of APRIL, which promoted the proliferation, migration, invasion, viability, and metastasis of GC cells, was upregulated in human H. pylori-infected GC through miR-145. Besides, APRIL-induced gastric tumorigenicity via activating NF-κB pathway. These results may provide a framework for the deeper analysis of APRIL in GC risk and prognosis.

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.

Insights into the molecular roles of heparan sulfate proteoglycans (HSPGs-syndecans) in autocrine and paracrine growth factor signaling in the pathogenesis of Hodgkin's lymphoma.

Syndecans (SDC, SYND) comprise a group of four structurally related type 1 transmembrane heparan sulfate proteoglycans (HSPGs) that play important roles in tumorigenic processes. SDCs exert signaling via their protein cores and their conserved transmembrane and cytoplasmic domains or by forming complexes with growth factors (GFs). In classical Hodgkin's lymphoma (cHL), a lymphoid neoplasm of predominantly B cell origin, SDC1 and SDC4 are the active SDCs, and a number of GF (vascular endothelial growth factor, fibroblast growth factor, etc.) signaling pathways have been studied. However, despite extensive pre-clinical and clinical research on SDC-mediated GF signaling in many cancer types, there is very limited data for this interaction in cHL. Thus, this review highlights the relevant literature focusing on the potential interactions of SDCs and GFs in cHL pathogenesis. Also discussed are the pre-clinical and clinical studies targeting signaling through these pathways.

The Role of TNF Superfamily Member 13 in the Progression of IgA Nephropathy.

TNF superfamily member 13 (TNFSF13) has been identified as a susceptibility gene for IgA nephropathy in recent genetic studies. However, the role of TNFSF13 in the progression of IgA nephropathy remains unresolved. We evaluated two genetic polymorphisms (rs11552708 and rs3803800) and plasma levels of TNFSF13 in 637 patients with IgA nephropathy, and determined the risk of ESRD according to theses variable. Neither of the examined genetic polymorphisms associated with a clinical outcome of IgA nephropathy. However, high plasma levels of TNFSF13 increased the risk of ESRD. To explore the causal relationship and underlying mechanism, we treated B cells from patients (n=21) with or without recombinant human TNFSF13 (rhTNFSF13) and measured the expression of IgA and galactose-deficient IgA (GdIgA) using ELISA and flow cytometry. Treatment with rhTNFSF13 significantly increased the total IgA level among B cells, and TNFSF13 receptor blockade abrogated this increase. Furthermore, the absolute levels of GdIgA increased with rhTNFSF13 treatment, but the total IgA-normalized levels did not change. Both RNA sequencing and quantitative PCR results showed that rhTNFSF13 did not alter the expression of glycosyltransferase enzymes. These results suggest that high plasma TNFSF13 levels associate with a worse prognosis of IgA nephropathy through the relative increase in GdIgA levels.

APRIL and BCMA promote human multiple myeloma growth and immunosuppression in the bone marrow microenvironment.

Here we show that overexpression or activation of B-cell maturation antigen (BCMA) by its ligand, a proliferation-inducing ligand (APRIL), promotes human multiple myeloma (MM) progression in vivo. BCMA downregulation strongly decreases viability and MM colony formation; conversely, BCMA overexpression augments MM cell growth and survival via induction of protein kinase B (AKT), MAPK, and nuclear factor (NF)-κB signaling cascades. Importantly, BCMA promotes in vivo growth of xenografted MM cells harboring p53 mutation in mice. BCMA-overexpressing tumors exhibit significantly increased CD31/microvessel density and vascular endothelial growth factor compared with paired control tumors. These tumors also express increased transcripts crucial for osteoclast activation, adhesion, and angiogenesis/metastasis, as well as genes mediating immune inhibition including programmed death ligand 1, transforming growth factor ß, and interleukin 10. These target genes are consistently induced by paracrine APRIL binding to BCMA on MM cells, which is blocked by an antagonistic anti-APRIL monoclonal antibody hAPRIL01A (01A). 01A is cytotoxic against MM cells even in the presence of protective bone marrow (BM) myeloid cells including osteoclasts, macrophages, and plasmacytoid dendritic cells. 01A further decreases APRIL-induced adhesion and migration of MM cells via blockade of canonical and noncanonical NF-κB pathways. Moreover, 01A prevents in vivo MM cell growth within implanted human bone chips in SCID mice. Finally, the effect of 01A on MM cell viability is enhanced by lenalidomide and bortezomib. Taken together, these data delineate new molecular mechanisms of in vivo MM growth and immunosuppression critically dependent on BCMA and APRIL in the BM microenvironment, further supporting targeting this prominent pathway in MM.

B cell activating factor (BAFF) and a proliferation inducing ligand (APRIL) mediate CD40-independent help by memory CD4 T cells.

Donor-reactive memory T cells undermine organ transplant survival and are poorly controlled by immunosuppression or costimulatory blockade. Memory CD4 T cells provide CD40-independent help for the generation of donor-reactive effector CD8 T cells and alloantibodies (alloAbs) that rapidly mediate allograft rejection. The goal of this study was to investigate the role of B cell activating factor (BAFF) and a proliferation-inducing ligand (APRIL) in alloresponses driven by memory CD4 T cells. The short-term neutralization of BAFF alone or BAFF plus APRIL synergized with anti-CD154 mAb to prolong heart allograft survival in recipients containing donor-reactive memory CD4 T cells. The prolongation was associated with reduction in antidonor alloAb responses and with inhibited reactivation and helper functions of memory CD4 T cells. Additional depletion of CD8 T cells did not enhance the prolonged allograft survival suggesting that donor-reactive alloAbs mediate late graft rejection in these recipients. This is the first report that targeting the BAFF cytokine network inhibits both humoral and cellular immune responses induced by memory CD4 T cells. Our results suggest that reagents neutralizing BAFF and APRIL may be used to enhance the efficacy of CD40/CD154 costimulatory blockade and improve allograft survival in T cell-sensitized recipients.

The role of a proliferation-inducing ligand (APRIL) in the pathogenesis of rheumatoid arthritis.

OBJECTIVES: To determine the differences in a proliferation-inducing ligand (APRIL) between seropositive and seronegative rheumatoid arthritis (RA) patients and further investigate the possible pathogenesis of the two subtypes of RA. METHOD: Concentrations of APRIL in sera (18 seropositive RA patients, 16 seronegative RA patients, and 10 healthy controls) and synovial fluid (SF) (eight seropositive RA patients, two seronegative RA patients, and 10 controls) were detected by enzyme-linked immunosorbent assay (ELISA). Infiltration of plasma cells, macrophages, and APRIL-positive cells in the synovium [14 seropositives, eight seronegatives, and 10 osteoarthritis (OA) controls] was detected by immunohistochemistry. Correlations between serum C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), 28-joint Disease Activity Score (DAS28), and sera/SF levels of APRIL and synovial cell infiltration were analysed. RESULTS: The mean serum APRIL level of seropositive RA patients was significantly higher than that of seronegative patients (26.1 ± 31.2 vs. 8.0 ± 10.2 ng/mL, p = 0.03). The level of APRIL in the SF of seropositive RA patients was comparable to that of seronegative patients [47.9 ± 54.4 vs. 32.82 (6.52-59.12) ng/mL, p > 0.05]. The SF APRIL level of RA patients was higher than that of patients with other inflammatory arthritis. Dramatically increased infiltration of APRIL-positive cells in the RA synovium was observed compared with the OA group (seropositive RA vs. OA, p < 0.001; seronegative RA vs. OA, p = 0.001). The infiltration of both plasma cells and macrophages was more in seropositive RA than in OA (p = 0.013 and p = 0.003, respectively). CONCLUSIONS: The serum APRIL levels of seropositive RA patients are significantly higher than those of seronegative RA patients. APRIL may participate in the formation of seropositive RA.

The BAFF/APRIL system in SLE pathogenesis.

Systemic lupus erythematosus (SLE) is characterized by multisystem immune-mediated injury in the setting of autoimmunity to nuclear antigens. The clinical heterogeneity of SLE, the absence of universally agreed clinical trial end points, and the paucity of validated therapeutic targets have, historically, contributed to a lack of novel treatments for SLE. However, in 2011, a therapeutic monoclonal antibody that neutralizes the cytokine TNF ligand superfamily member 13B (also known as B-cell-activating factor of the TNF family [BAFF]), belimumab, became the first targeted therapy for SLE to have efficacy in a randomized clinical trial. Because of its specificity, the efficacy of belimumab provides an opportunity to increase understanding of SLE pathophysiology. Although belimumab depletes B cells, this effect is not as powerful as that of other B-cell-directed therapies that have not been proven efficacious in randomized clinical trials. In this article, therefore, we review results suggesting that neutralizing BAFF can have effects on the immune system other than depletion of B cells. We also identify aspects of the BAFF system for which data in relation to SLE are still missing, and we suggest studies to investigate the pathogenesis of SLE and ways to refine anti-BAFF therapies. The role of a related cytokine, TNF ligand superfamily member 13 (also known as a proliferation-inducing ligand [APRIL]) in SLE is much less well understood, and hence this review focuses on BAFF.

CCL19 and CCL28 augment mucosal and systemic immune responses to HIV-1 gp140 by mobilizing responsive immunocytes into secondary lymph nodes and mucosal tissue.

Induction of broad and potent neutralizing Abs at the mucosal portals of entry remains a primary goal for most vaccines against mucosally acquired viral infections. Selection of appropriate adjuvants capable of promoting both systemic and mucosal responses will be crucial for the development of effective immunization strategies. In this study, we investigated whether plasmid codelivery of cytokines APRIL, CCL19, or CCL28 can enhance Ag-induced immune responses to HIV-1 gp140. Our results demonstrated that pCCL19 and pCCL28, but not pAPRIL, significantly enhanced Ag-specific systemic and mucosal Ab responses. gp140-specific Abs in serum enhanced by pCCL19 or pCCL28 were broadly distributed across all four IgG subclasses, of which IgG1 was predominant. The enhanced systemic and mucosal Abs showed increased neutralizing activity against both homologous and heterologous HIV-1, and potency correlated with gp140-specific serum IgG and vaginal IgA levels. Measurement of gp140-specific cytokines produced by splenocytes demonstrated that pCCL19 and pCCL28 augmented balanced Th1/Th2 responses. pCCL19 and pCCL28 also increased IgA(+) cells in colorectal mucosal tissue. pCCL19 codelivery resulted in an increase of CCR7(+) CD11c(+) cells in mesenteric lymph nodes and both CCR7(+) CD11c(+) cells and CCR7(+) CD3e(+) cells in spleen, whereas pCCL28 codelivery resulted in an augment of CCR10(+) CD19(+) cells in both spleen and mesenteric lymph nodes. Together, our data indicate that pCCL19 and pCCL28 can enhance HIV-1 envelope-specific systemic and mucosal Ab responses, as well as T cell responses. Such enhancements appear to be associated with mobilization of responsive immunocytes into secondary lymphoid organs and mucosal tissues through interactions with corresponding receptors.

A capture-sequencing strategy identifies IRF8, EBF1, and APRIL as novel IGH fusion partners in B-cell lymphoma.

The characterization of immunoglobulin heavy chain (IGH) translocations provides information on the diagnosis and guides therapeutic decisions in mature B-cell malignancies while enhancing our understanding of normal and malignant B-cell biology. However, existing methodologies for the detection of IGH translocations are labor intensive, often require viable cells, and are biased toward known IGH fusions. To overcome these limitations, we developed a capture sequencing strategy for the identification of IGH rearrangements at nucleotide level resolution and tested its capabilities as a diagnostic and discovery tool in 78 primary diffuse large B-cell lymphomas (DLBCLs). We readily identified IGH-BCL2, IGH-BCL6, IGH-MYC, and IGH-CCND1 fusions and discovered IRF8, EBF1, and TNFSF13 (APRIL) as novel IGH partners in these tumors. IRF8 and TNFSF13 expression was significantly higher in lymphomas with IGH rearrangements targeting these loci. Modeling the deregulation of IRF8 and EBF1 in vitro defined a lymphomagenic profile characterized by up-regulation of AID and/or BCL6, down-regulation of PRMD1, and resistance to apoptosis. Using a capture sequencing strategy, we discovered the B-cell relevant genes IRF8, EBF1, and TNFSF13 as novel targets for IGH deregulation. This methodology is poised to change how IGH translocations are identified in clinical settings while remaining a powerful tool to uncover the pathogenesis of B-cell malignancies.

The BAFF/APRIL system: emerging functions beyond B cell biology and autoimmunity.

The BAFF system plays a key role in the development of autoimmunity, especially in systemic lupus erythematosus (SLE). This often leads to the assumption that BAFF is mostly a B cell factor with a specific role in autoimmunity. Focus on BAFF and autoimmunity, driven by pharmaceutical successes with the recent approval of a novel targeted therapy Belimumab, has relegated other potential roles of BAFF to the background. Far from being SLE-specific, the BAFF system has a much broader relevance in infection, cancer and allergy. In this review, we provide the latest views on additional roles of the BAFF system in health and diseases, as well as an update on BAFF and autoimmunity, with particular focus on current clinical trials.

Targeting the BLyS-APRIL signaling pathway in SLE.

The B lymphocyte stimulator (BLyS)-A PRoliferation-Inducing Ligand (APRIL) signaling pathway has an important role in the selection, maturation and survival of B cells and plays a significant role in the pathogenesis of systemic lupus erythematosus (SLE). The inhibition of BLyS, a survival factor for transitional and mature B cells, has recently proven to be successful in large phase III clinical trials that led to the approval of an anti-BLyS monoclonal antibody (belimumab) for the treatment of SLE. Yet, there is currently a need to both understand better the mechanisms of action of belimumab in SLE and better define the subsets of patients that are more likely to respond to the drug.

B-cell maturation antigen, a proliferation-inducing ligand, and B-cell activating factor are candidate mediators of spinal cord injury-induced autoimmunity.

Autoimmunity is thought to contribute to poor neurological outcomes after spinal cord injury (SCI). There are few mechanism-based therapies, however, designed to reduce tissue damage and neurotoxicity after SCI because the molecular and cellular bases for SCI-induced autoimmunity are not completely understood. Recent groundbreaking studies in rodents indicate that B cells are responsible for SCI-induced autoimmunity. This novel paradigm, if confirmed in humans, could aid in the design of neuroprotective immunotherapies. The aim of this study was to investigate the molecular signaling pathways and mechanisms by which autoimmunity is induced after SCI, with the goal of identifying potential targets in therapies designed to reduce tissue damage and inflammation in the chronic phase of SCI. To that end, we performed an exploratory microarray analysis of peripheral blood mononuclear cells to identify differentially expressed genes in chronic SCI. We identified a gene network associated with lymphoid tissue structure and development that was composed of 29 distinct molecules and five protein complexes, including two cytokines, a proliferation-inducing ligand (APRIL) and B-cell-activating factor (BAFF), and one receptor, B-cell maturation antigen (BMCA) involved in B cell development, proliferation, activation, and survival. Real-time polymerase chain reaction analysis from ribonucleic acid samples confirmed upregulation of these three genes in SCI. To our knowledge, this is the first report that peripheral blood mononuclear cells produce increased levels of BAFF and APRIL in chronic SCI. This finding provides evidence of systemic regulation of SCI-autoimmunity via APRIL and BAFF mediated activation of B cells through BMCA and points toward these molecules as potential targets of therapies designed to reduce neuroinflammation after SCI.

The rationale for BAFF inhibition in systemic lupus erythematosus.

BAFF (B-cell-activating factor) is a critical survival factor for transitional and mature B cells and is a promising therapeutic target for systemic lupus erythematosus (SLE). In 2010-2011, two phase 3 clinical trials showed that the addition of the anti-BAFF antibody belimumab to standard-of-care therapy in patients with moderately active SLE results in a better outcome at 52 weeks than standard-of-care therapy alone. Belimumab has been US Food and Drug Administration approved for the treatment of SLE, and other drugs that target BAFF are now in various stages of clinical testing. This review describes the function of BAFF and its homolog APRIL (a proliferation-inducing ligand) and addresses the rationale for the treatment of SLE with BAFF/APRIL inhibitors.

Selective APRIL blockade delays systemic lupus erythematosus in mouse.

SLE pathogenesis is complex, but it is now widely accepted that autoantibodies play a key role in the process by forming excessive immune complexes; their deposits within tissues leading to inflammation and functional damages. A proliferation inducing ligand (APRIL) is a member of the tumor necrosis factor (TNF) superfamily mediating antibody-producing plasma cell (PC)-survival that may be involved in the duration of pathogenic autoantibodies in lupus. We found significant increases of APRIL at the mRNA and protein levels in bone marrow but not spleen cells from NZB/W lupus mice, as compared to control mice. Selective antibody-mediated APRIL blockade delays disease development in this model by preventing proteinuria, kidney lesions, and mortality. Notably, this was achieved by decreasing anti-DNA and anti-chromatin autoantibody levels, without any perturbation of B- and T-cell homeostasis. Thus, anti-APRIL treatment may constitute an alternative therapy in SLE highly specific to PCs compared to other B-cell targeting therapies tested in this disease, and likely to be associated with less adverse effects than any anti-inflammatory and immunosuppressant agents previously used.

Molecular cloning and partial functional characterization of a proliferation inducing ligand (APRIL) in zebrafish (Danio rerio).

Here we describe the identification of a Danio rerio homologue of a proliferation-inducing ligand (APRIL) of the TNF family (designated zAPRIL). Sequence analysis showed that the open reading frame of zAPRIL consists of 600 bases encoding a protein of 199-amino acids. Recombinant soluble APRIL (zsAPRIL) was constructed consisting of fluorescence-enhanced green fluorescent protein (EGFP) and cloned into a pET28a vector. SDS-PAGE and western blotting analysis indicated a high-level expression of soluble EGFP/zsAPRIL protein in Escherichia coli BL21 (DE3). Observation by confocal microscopy demonstrated that EGFP/zsAPRIL could successfully bind to the surface receptors of zebrafish lymphocytes. In vitro survival analysis revealed that purified EGFP/zsAPRIL was able to promote the survival of zebrafish lymphocytes in a dose-dependent manner. The biological role of APRIL does not seem to be restricted to proliferation induction. Zebrafish may could served as a model organism for further study of APRIL.

[Interleukins network in rheumatoid arthritis pathophysiology: beyond proinflammatory cytokines]. / Interleucinas en la fisiopatología de la artritis reumatoide: más allá de las citocinas proinflamatorias.

Rheumatoid arthritis (RA) is a systemic autoimmune disease characterized by synovitis and progressive destruction of the joint cartilage and underlying bone, together with diverse extra-articular manifestations. Cytokines act as soluble effector mediators of the inflammatory process. Therapeutic neutralization with monoclonal antibodies against the pro-inflammatory cytokines TNF-alpha and interleukin 1 (IL-1) has shown a clear efficacy on inflammation and clinical manifestations of RA, although a percentage of patients do not respond. This review covers new relevant cytokines in the RA physiopathology and potential biomarkers of inflammation. The current challenge is to develop biomarkers that enable an earlier diagnosis, as well as prognostic markers and new therapeutic candidates. Combined administration of several of these cytokines could eventually address a personalized treatment approach for each patient.

[Encounter of cancer cells with bone. Cancer and inflammation--input and output of NF-κB - ].

NF-κB activation is frequently found in a variety of tumors, especially in those that are resistant to chemotherapy. The malignant phenotypes of tumor cells that are required for invasion and metastasis could be established by the output of NF-κB signaling including interactions with white blood cells, anti-apoptosis and angiogenesis. Consequently, by utilizing the similar mechanisms for immune cells to migrate through the body, tumor cells migrate via blood stream, survive against selective pressures in other organs they stop by, achieve re-growth as metastasis, or make a clinical relapse by traveling back to the primary site.

Prominent role for plasmacytoid dendritic cells in mucosal T cell-independent IgA induction.

Although both conventional dendritic cells (cDCs) and plasmacytoid dendritic cells (pDCs) are present in the gut-associated lymphoid tissues (GALT), the roles of pDCs in the gut remain largely unknown. Here we show a critical role for pDCs in T cell-independent (TI) IgA production by B cells in the GALT. When pDCs of the mesenteric lymph nodes (MLNs) and Peyer's patches (PPs) (which are representative GALT) were cultured with naive B cells to induce TI IgA class switch recombination (CSR), IgA production was substantially higher than in cocultures of these cells with cDCs. IgA production was dependent on APRIL and BAFF production by pDCs. Importantly, pDC expression of APRIL and BAFF was dependent on stromal cell-derived type I IFN signaling under steady-state conditions. Our findings provide insight into the molecular basis of pDC conditioning to induce mucosal TI IgA production, which may lead to improvements in vaccination strategies and treatment for mucosal-related disorders.

Evaluation of TNF superfamily molecules release by neutrophils and B leukemic cells of patients with chronic B - cell lymphocytic leukemia.

It was demonstrated that TNF superfamily proteins may affect significantly the time of leukemic cells' survival in the course of B-cell chronic lymphocytic leukemia (B-CLL). The aim of our study was to evaluate the expression and release of BAFF (B-cell activating factor), APRIL (a proliferation-inducing ligand) and TRAIL (TNF-related apoptosis inducing ligand) molecules belonging to the cytokines of the superfamily of the tumor necrosis factor (TNF) by neutrophils (PMNs) and, for comparison, B cells isolated from the blood of patients with B-CLL vs. their concentration in the blood serum. 40 patients suffering from B-CLL and a control group of 15 healthy subjects were included in the study. Cytoplasmic fractions of PMNs and B cells were analyzed with the use of western blotting for the presence of TRAIL, BAFF and APRIL. Soluble TRAIL, BAFF and APRIL in the culture supernatants and the serum were assessed using ELISA kits. PMNs and B cells of patients with B-CLL before treatment demonstrated the statistically significantly higher expression of APRIL and BAFF proteins when compared with the control group of healthy subjects. In contrast, the expression of TRAIL protein in both types of cells of patients was statistically significantly lower than its expression in the control cells. In the supernatants of PMN and B lymphocytes of patients the decreased concentrations of sBAFF, unchanged of APRIL and increased of sTRAIL molecules were demonstrated. The results of studies carried out in patients with B-CLL before treatment indicate that the relations demonstrated between APRIL, BAFF and TRAIL molecules, released by neutrophils and B cells and relations between their concentrations in the serum can significantly influence the development of B-CLL.