B-cell Lymphoma/leukemia 10 Research Articles

Exacerbation by knocking-out metallothionein gene of obesity-induced cardiac remodeling is associated with the activation of CARD9 signaling.

Obesity increases the risk of metabolic syndrome including insulin resistance, dyslipidemia, and cardiovascular disease. We demonstrated insulin resistance, cardiac hypertrophy, and cardiac inflammation in an obese mouse model induced by a high-fat diet (HFD). Caspase recruitment domain-containing protein 9 (CARD9) and B-cell lymphoma/leukemia 10 (BCL10) were upregulated, and p38 MAPK was activated in these mice. Zinc supplementation prevented these changes with upregulation of metallothionein (MT). Deletion of MT exacerbated palmitate-triggered expression of BCL10 and p38 MAPK activation and eliminated the protective benefits of zinc in palmitate-treated cardiomyocytes. Here we further investigated the mechanisms by which endogenous MT expression affects HFD-induced cardiac remodeling and the CARD9/BCL10/p38 MAPK pathway. Male MT knockout and 129S wild-type mice were assigned to receive either a normal diet or a HFD from 8-week-age for 18 weeks. MT knockout (KO) aggravated HFD-induced obesity and systemic metabolic disorder, reflected by increased body weight, perirenal white adipose tissue, and plasma cholesterol, and cardiac hypertrophy and fibrosis. Obese MT-KO mice had abundant cardiac macrophages, upregulated cardiac proinflammatory cytokines, chemokines, adhesion molecules, CARD9, and BCL10 and activated NF-κB. MT-KO exacerbated HFD-induced trace metal dyshomeostasis and oxidative stress. MT-KO combined with HFD-induced obesity synergistically promotes cardiac remodeling, possibly via trace metal dyshomeostasis-induced oxidative stress to trigger CARD9/BCL10-mediated NF-κB activation.

Differentially expressed proteins and microbial communities of the skin regulate disease resistance to Chinese tongue sole (Cynoglossus semilaevis).

Vibriosis, caused by Vibrio, seriously affects the health of fish, shellfish, and shrimps, causing large economic losses. Teleosts are represent the first bony vertebrates with both innate and adaptive immune responses against pathogens. Aquatic animals encounter hydraulic pressure and more pathogens, compared to terrestrial animals. The skin is the first line of defense in fish, constituting the skin-associated lymphoid tissue (SALT), which belongs to the main mucosa-associated lymphoid tissues (MALT). However, little is known about the function of immunity related proteins in fish. Therefore, this study used iTRAQ (isobaric tags for relative and absolute quantitation) to compare the skin proteome between the resistant and susceptible families of Cynoglossus semilaevis. The protein integrin beta-2, the alpha-enolase isoform X1, subunit B of V-type proton ATPase, eukaryotic translation initiation factor 6, and ubiquitin-like protein ISG15, were highly expressed in the resistant family. The 16S sequencing of the skin tissues of the resistant and susceptible families showed significant differences in the microbial communities of the two families. The protein-microbial interaction identified ten proteins associated with skin microbes, including immunoglobulin heavy chain gene (IGH), B-cell lymphoma/leukemia 10 (BCL10) and pre-B-cell leukemia transcription factor 1 isoform X2 (PBX2). This study highlights the interaction between skin proteins and the microbial compositions of C. semilaevis and provides new insights into understanding aquaculture breeding research.

MicroRNA‑155‑5p affects regulatory T cell activation and immunosuppressive function by targeting BCL10 in myasthenia gravis.

The imbalance in immune homeostasis plays a crucial role in the pathogenesis of myasthenia gravis (MG). MicroRNAs (miRs) have been identified as key regulators of immune homeostasis. B-cell lymphoma/leukemia 10 (BCL10) has been implicated in the activation and suppressive function of regulatory T cells (Tregs). This study aimed to investigate the potential role of miR-155-5p in modulating the activation and function of Tregs in MG. To achieve this objective, blood samples were collected from MG patients to assess the expression levels of miR-155-5p and BCL10, as well as the proportion of circulating Tregs, in comparison to healthy controls. The correlation between miR-155-5p and BCL10 levels was evaluated in human samples. The expression levels of miR-155-5p and the numbers of circulating Tregs were also examined in an animal model of experimental autoimmune MG (EAMG). A dual-luciferase reporter assay was used to verify whether miR-155-5p can target BCL10. To determine the regulatory function of BCL10 in Tregs, CD4+ CD25+ Tregs were transfected with either small interfering-BCL10 or miR-155-5p inhibitor, and the expression levels of the anti-inflammatory cytokine IL-10 and transcription factors Foxp3, TGF-β1, CTLA4, and ICOS were measured. The results demonstrated that the expression level of miR-155-5p was significantly higher in patients with MG compared with that in healthy controls, whereas the expression level of BCL10 was significantly decreased in patients with MG. Furthermore, there was a significant negative correlation between the expression levels of miR-155-5p and BCL10. The number of circulating Tregs was significantly reduced in patients with MG and in the spleen of rats with EAMG compared with that in the corresponding control groups. The dual-luciferase reporter assay demonstrated that miR-155-5p could target BCL10. The Tregs transfected with si-BCL10 demonstrated significant decreases in the protein levels of TGF-β1 and IL-10, as well as in the mRNA expression levels of Foxp3, TGF-β1, CTLA-4 and ICOS. Conversely, the Tregs transfected with the miR-155-5p inhibitor exhibited a substantial increase in these protein and mRNA expression levels compared with their respective control groups. Furthermore, the knockdown of BCL10 exhibited a decline in the suppressive efficacy of Tregs on the proliferation of CD4+ T cells. Conversely, the suppression of miR-155-5p expression attenuated the inhibition of the BCL10 gene, potentially causing an indirect influence on the suppressive capability of Tregs on the proliferation of CD4+ T cells. BCL10 was thus found to contribute to the activation and immunosuppressive function of Tregs. In summary, the present study demonstrated that miR-155-5p inhibited the activation and immunosuppressive function of Tregs by targeting BCL10, which may be used as a future potential target for the treatment of MG.

BCL10 regulates the production of proinflammatory cytokines by activating MAPK–NF–κB/Rel signaling pathway in oysters

B cell lymphoma/leukemia 10 (BCL10) is an important member of the caspase recruitment domain-containing (CARD) protein family, which plays crucial roles in mediating the host inflammatory response. In the present study, a BCL10 homologue was identified from Pacific oyster Crassostrea gigas (designed as CgBCL10). The full length cDNA of CgBCL10 was of 897 bp with an open reading frame of 522 bp encoding a polypeptide of 174 amino acids containing a classical CARD domain. The deduced amino acid sequence of CgBCL10 shared low similarity with the previously identified BCL10s from other species. In the phylogenetic tree, CgBCL10 was firstly clustered with CvBCL10 from Crassostrea virginica and then assigned into the branch of invertebrate BCL10s. The mRNA transcripts of CgBCL10 were highly expressed in gonad, gill, adductor muscle, and haemocytes. After Vibrio splendidus stimulation, the mRNA expression level of CgBCL10 in haemocytes increased significantly (p < 0.01) at 24, 72 and 96 h. In CgBCL10-RNAi oysters, the phosphorylation level of mitogen-activated protein kinases (MAPKs), nuclear translocation of NF-κB/Rel and activator protein-1 (AP-1) in haemocytes were inhibited, and the mRNA expressions of inflammatory cytokines including CgIL17-1, CgIL17-2, CgIL17-3, CgIL17-6 and CgTNF all decreased significantly (p < 0.01) at 12 h after V. splendidus stimulation. These results suggested that CgBCL10 regulated the expression of inflammatory cytokines by activating MAPK kinase, and nuclear translocation of NF-κB/Rel and AP-1 to defense pathogen.

USP12 promotes CD4+ T cell responses through deubiquitinating and stabilizing BCL10

Deubiquitinases (DUBs) regulate diverse biological processes and represent a novel class of drug targets. However, the biological function of only a small fraction of DUBs, especially in adaptive immune response regulation, is well-defined. In this study, we identified DUB ubiquitin-specific peptidase 12 (USP12) as a critical regulator of CD4+ T cell activation. USP12 plays an intrinsic role in promoting the CD4+ T cell phenotype, including differentiation, activation, and proliferation. Although USP12-deficient CD4+ T cells protected mice from autoimmune diseases, the immune response against bacterial infection was subdued. USP12 stabilized B cell lymphoma/leukemia 10 (BCL10) by deubiquitinating, and thereby activated the NF-κB signaling pathway. Interestingly, this USP12 regulatory mechanism was identified in CD4+ T cells, but not in CD8+ T cells. Our study results showed that USP12 activated CD4+ T cell signaling, and targeting USP12 might help develop therapeutic interventions for treating inflammatory diseases or pathogen infections.

Gene Expression Alterations Associated with Oleuropein-Induced Antiproliferative Effects and S-Phase Cell Cycle Arrest in Triple-Negative Breast Cancer Cells.

It is known that the Mediterranean diet is effective in reducing the risk of several chronic diseases, including cancer. A critical component of the Mediterranean diet is olive oil, and the relationship between olive oil consumption and the reduced risk of cancer has been established. Oleuropein (OL) is the most prominent polyphenol component of olive fruits and leaves. This compound has been shown to have potent properties in various types of cancers, including breast cancer. In the present study, the molecular mechanism of OL was examined in two racially different triple-negative breast cancer (TNBC) cell lines—African American (AA, MDA-MB-468) and Caucasian American (CA, MDA-MB-231). The data obtained showed that OL effectively inhibits cell growth in both cell lines, concomitant with S-phase cell cycle arrest-mediated apoptosis. The results also showed that OL-treated MDA-MB-468 cells were two-fold more sensitive to OL antiproliferative effect than MDA-MB-231 cells were. At lower concentrations, OL modified the expression of many apoptosis-involved genes. OL was more effective in MDA-MB-468, compared to MDA-MB-231 cells, in terms of the number and the fold-change of the altered genes. In MDA-MB-468 cells, OL induced a noticeable transcription activation in fourteen genes, including two members of the caspase family: caspase 1 (CASP1) and caspase 14 (CASP14); two members of the TNF receptor superfamily: Fas-associated via death domain (FADD) and TNF receptor superfamily 21 (TNFRSF21); six other proapoptotic genes: growth arrest and DNA damage-inducible 45 alpha (GADD45A), cytochrome c somatic (CYCS), BCL-2 interacting protein 2 (BNIP2), BCL-2 interacting protein 3 (BNIP3), BH3 interacting domain death agonist (BID), and B-cell lymphoma/leukemia 10 (BCL10); and the CASP8 and FADD-like apoptosis regulator (CFLAR) gene. Moreover, in MDA-MB-468 cells, OL induced a significant upregulation in two antiapoptotic genes: bifunctional apoptosis regulator (BFAR) and B-Raf proto-oncogene (BRAF) and a baculoviral inhibitor of apoptosis (IAP) repeat-containing 3 (BIRC3). On the contrary, in MDA-MB-231 cells, OL showed mixed impacts on gene expression. OL significantly upregulated the mRNA expression of four genes: BIRC3, receptor-interacting serine/threonine kinase 2 (RIPK2), TNF receptor superfamily 10A (TNFRSF10A), and caspase 4 (CASP4). Additionally, another four genes were repressed, including caspase 6 (CASP6), pyrin domain (PYD), and caspase recruitment domain (CARD)-containing (PAYCARD), baculoviral IAP repeat-containing 5 (BIRC5), and the most downregulated TNF receptor superfamily member 11B (TNFRSF11B, 16.34-fold). In conclusion, the data obtained indicate that the two cell lines were markedly different in the anticancer effect and mechanisms of oleuropein’s ability to alter apoptosis-related gene expressions. The results obtained from this study should also guide the potential utilization of oleuropein as an adjunct therapy for TNBC to increase chemotherapy effectiveness and prevent cancer progression.

By regulating miR-182-5p/&lt;i&gt;BCL10&lt;/i&gt;/&lt;i&gt;CYCS&lt;/i&gt;, sufentanil reduces the apoptosis of umbilical cord mesenchymal stem cells caused by ropivacaine

Sufentanil is a type of opioid analgesic and is usually used to facilitate painless labor in combination with the local anesthetic ropivacaine. One aim of the current study was to investigate the effects of sufentanil and ropivacaine on umbilical cord mesenchymal stem cells (UCMSCs). A second aim of this study was to determine whether sufentanil attenuated the cytotoxicity of ropivacaine in vitro. UCMSCs were divided into 3 groups: one was treated with ropivacaine at a concentration of 50, 100, 200, or 400 μg/mL, another was treated with sufentanil at a concentration of 0.5, 5, 50, or 500 nmol/L, and a third was treated with a combination of ropivacaine at a concentration of 200 μg/mL and sufentanil at a concentration of 0.5, 5, 50, or 500 nmol/L. Results indicated that cell proliferation decreased in cells treated with ropivacaine while it increased in cells treated with sufentanil. In addition, sufentanil limited the inhibitory effect of ropivacaine on UCMSC growth in a dose- and time-dependent manner. Combined treatment with ropivacaine at a concentration of 200 μg/mL and sufentanil at a concentration of 500 nmol/L decreased the proportion of dead and apoptotic UCMSCs, and fewer cells were arrested in the S phase compared to cells treated with ropivacaine. Sufentanil inhibited the apoptosis induced by ropivacaine by increasing miR-182-5p, which regulated the expression of mRNA of the pro-apoptotic genes B-cell lymphoma/leukemia 10 (BCL10) and cytochrome c, somatic (CYCS). Sufentanil also increased the expression of mRNA of anti-apoptotic genes. In short, ropivacaine inhibits the cell viability and induces the apoptosis of UCMSCs in vitro while sufentanil attenuates this apoptosis by regulating miR182-5p/BCL10/CYCS.

BCL10 - Bridging CARDs to Immune Activation.

Since the B-cell lymphoma/leukemia 10 (BCL10) protein was first described in 1999, numerous studies have elucidated its key functions in channeling adaptive and innate immune signaling downstream of CARMA/caspase-recruitment domain (CARD) scaffold proteins. While T and B cell antigen receptor (TCR/BCR) signaling induces the recruitment of BCL10 bound to mucosa-associated lymphoid tissue (MALT)1 to the lymphocyte-specific CARMA1/CARD11–BCL10–MALT1 (CBM-1) signalosome, alternative CBM complexes utilize different CARMA/CARD scaffolds in distinct innate or inflammatory pathways. BCL10 constitutes the smallest subunit in all CBM signalosomes, containing a 233 amino acid coding for N-terminal CARD as well as a C-terminal Ser/Thr-rich region. BCL10 forms filaments, thereby aggregating into higher-order clusters that mediate and amplify stimulation-induced signals, ultimately leading to MALT1 protease activation and canonical NF-κB and JNK signaling. BCL10 additionally undergoes extensive post-translational regulation involving phosphorylation, ubiquitination, MALT1-catalyzed cleavage, and degradation. Through these feedback and feed-forward events, BCL10 integrates positive and negative regulatory processes that govern the function as well as the dynamic assembly, disassembly, and destruction of CBM complexes. Thus, BCL10 is a critical regulator for activation as well as termination of immune cell signaling, revealing that its role extends far beyond that of a mere linking factor in CBM complexes.

A CARD10-Dependent Tonic Signalosome Activates MALT1 Paracaspase and Regulates IL-17/TNF-α–Driven Keratinocyte Inflammation

The paracaspase MALT1 (Mucosa associated lymphoid tissue lymphoma translocation protein 1) controls signaling downstream of several cell surface receptors, such as C-type lectin receptors on myeloid cells and antigen receptors on lymphocytes. Upon receptor engagement, MALT1, BCL10 (B-cell lymphoma/leukemia 10) and a CARD (Caspase recruitment domain) family member assemble into a ‘CBM’ complex, which is required to trigger MALT1 paracaspase activity and downstream transcriptional activation mechanisms (Meininger and Krappmann 2016; Rosebeck et al. 2011). Here, we found that CARD10 is highly expressed in proliferating keratinocytes and is responsible for a tonic level of paracaspase activity, driven by MALT1 isoform A. Furthermore, using the potent and selective MALT1 inhibitor MLT-827 (Bardet et al. 2018; Unterreiner et al. 2017), we reveal that MALT1 activity regulates pro-inflammatory responses downstream of IL-17/TNF-α.

B-cell lymphoma/leukemia 10 promotes oral cancer progression through STAT1/ATF4/S100P signaling pathway.

This corrects the article DOI: 10.1038/onc.2014.43.

Abstract 3015: BCL10 is a novel DNA damage response factor whose expression inversely correlates with the clinical outcome of breast invasive ductal carcinoma

Abstract Timely and properly cellular response to DNA damage is essential for maintenance of genome stability and integrity. B-cell lymphoma/leukemia 10 (BCL10) facilitates ubiquitination of NEMO in the cytosol, activating NFκB signaling. Translocation and/or point mutations of BCL10 associate with mucosa-associated lymphoid tissue lymphomas and other malignancies. We recently found that BCL10 in nucleus is enriched onto the DNA damage sites in an ATM- and RNF8-dependent manner, and ATM-dependent phosphorylation and RNF8-dependent ubiquitination of BCL10 confers UBC13 to RNF8/RNF168 to regulate ubiquitination-mediated DSB signaling and repair. In this report, we further found that inhibition of BCL10 expression compromised RNF168 dimerization and RNF168-dependent histone H2A ubiquitination. Immunohistochemistry staining analysis revealed that BCL10 expression status inversely correlates with prognosis in 339 cases of breast invasive ductal carcinoma with a median follow up of 60 months (range, 3-127 months). Taken together, our results demonstrated that BCL10 is a novel DDR factor with a potential role as a biomarker in breast cancer therapy. Note: This abstract was not presented at the meeting. Citation Format: Min Zhu, Hongchang Zhao, Xingzhi Xu. BCL10 is a novel DNA damage response factor whose expression inversely correlates with the clinical outcome of breast invasive ductal carcinoma. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3015. doi:10.1158/1538-7445.AM2015-3015

Abstract 2409: BCL10 regulates RNF8/RNF168-mediated ubiquitination in the DNA damage response

Abstract Our genome is constantly attacked by a variety of endogenous and environmental agents. Timely and properly cellular response to DNA damage is essential for maintenance of genome stability and integrity, which plays key roles in prevention of tumor initiation and development. B-cell lymphoma/leukemia 10 (BCL10), when translocated or mutated, contributes to mucosa-associated lymphoid tissue lymphomas and other malignancies. However, the mechanisms by which the resulting aberrant expression of BCL10 leads to tumorigenesis are poorly understood. In this report, we uncovered that, in response to DNA damage, BCL10 is recruited to the damage sites and modified sequentially by phosphorylation and ubiquitination. Modified BCL10 in turn facilitates to bring about cascades of ubiquitination and recruitment of DNA damage response (DDR) factors, promoting high-fidelity DNA repair. Furthermore, BCL10 is over-expressed in breast tumors (376 cases of breast cancer vs. 62 cases of normal breast, p=0.000). Taken together, our study reveals a novel function of BCL10 in ubiquitination-driven DDR, contributing to the maintenance of genome stability and integrity. Note: This abstract was not presented at the meeting. Citation Format: Hongchang Zhao, Min Zhu, Xingzhi Xu. BCL10 regulates RNF8/RNF168-mediated ubiquitination in the DNA damage response. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2409. doi:10.1158/1538-7445.AM2014-2409

BCL10 regulates RNF8/RNF168-mediated ubiquitination in the DNA damage response

Timely and proper cellular response to DNA damage is essential for maintenance of genome stability and integrity. B-cell lymphoma/leukemia 10 (BCL10) facilitates ubiquitination of NEMO in the cytosol, activating NFκB signaling. Translocation and/or point mutations of BCL10 associate with mucosa-associated lymphoid tissue lymphomas and other malignancies. However, the mechanisms by which the resulting aberrant expression of BCL10 leads to cellular oncogenesis are poorly understood. In this report, we found that BCL10 in the nucleus is enriched at the DNA damage sites in an ATM- and RNF8-dependent manner. ATM-dependent phosphorylation of BCL10 promotes its interaction with and presentation of UBC13 to RNF8, and RNF8-mediated ubiquitination of BCL10 enhances binding of BCL10 and UBC13 to RNF168. This allows mono-ubiquitination on H2AX by RNF168 and further poly-ubiquitination by the RNF8/RNF168-containing complex. Depletion of BCL10 compromised homology recombination-mediated DNA double-strand break (DSB) repair because of insufficient recruitment of BRCA1, RAD51, and the ubiquitinated DNA damage response factors. Taken together, our results demonstrate a novel function of BCL10 in delivering UBC13 to RNF8/RNF168 to regulate ubiquitination-mediated DSB signaling and repair.

B-cell lymphoma/leukemia 10 promotes oral cancer progression through STAT1/ATF4/S100P signaling pathway

B-cell lymphoma/leukemia 10 (BCL10) is an apoptotic regulatory protein related to advanced TNM stage and disease recurrence in oral squamous cell carcinoma (OSCC). However, the regulatory mechanism of BCL10 in OSCC progression is still unknown. Here, we showed that knockdown of endogenous BCL10 could significantly reduce cell migration and invasion abilities, retard cell proliferation by G0/G1 phase accumulation and inhibit tumorigenicity in vivo. In molecular level, we identified S100P as a crucial downstream effector of BCL10-inhibited OSCC progression by high-throughput microarray analysis. S100P messenger RNA and protein expression levels were significantly diminished in silenced-BCL10 clones, and transfected S100P expression plasmids restored migration, invasion, proliferation abilities and tumorigenicity in shBCL10 transfectants. Furthermore, we provided evidence that BCL10 regulated S100P expression through signal transducers and activators of transcription 1 (STAT1) and activating transcription factor 4 (ATF4). Knockdown of BCL10 decreased S100P promoter activity, but showed no effect in truncated STAT1/ATF4 S100P promoter. In addition, we also found that the P50/P65 signaling pathway was involved in BCL10-enhanced OSCC progression. Restored S100P in silenced-BCL10 clones could markedly reverse P65 activation via outside-in signaling. Taken together, we discovered a novel axis of BCL10-regulated OSCC progression via STAT1/ATF4/S100P/P65 signaling, which could predict the prognosis of OSCC and will be beneficial for developing therapeutic strategy against advanced OSCC.

Forkhead Transcription Factor FOXO3a Protein Activates Nuclear Factor κB through B-cell lymphoma/leukemia 10 (BCL10) Protein and Promotes Tumor Cell Survival in Serum Deprivation

FOXO3a, a member of the Forkhead box O (FoxO) transcription factor family, is believed to be a tumor suppressor because it was found that FOXO3a inactivation promoted cell transformation and tumor progression. There are also a few studies showing that FOXO3a protected cells under stress conditions, including oxidative stress, serum deprivation, and hypoxia. It was reported that FOXO3a promoted invasion of cancer cells. Thus, the role of FOXO3a in cancer is complicated. Here, we report that FOXO3a is a positive regulator of nuclear factor κB (NF-κB) signaling. We found that overexpression of FOXO3a increased and knockdown of FOXO3a repressed NF-κB activities. Mechanistic studies indicate that FOXO3a activated NF-κB via inducing expression of B-cell lymphoma/leukemia 10 (BCL10), an upstream regulator of IκB kinase (IKK)/NF-κB signaling. We found that the serum deprivation activated NF-κB, which was blocked by inhibition of FOXO3a. Knockdown of FOXO3a enhanced cell apoptosis under serum-free conditions, which was inhibited by overexpression of BCL10. These results suggest that FOXO3a promotes cell survival via BCL10/NF-κB in serum starvation. Our findings may add another layer to the complexity of the role of FOXO3a in cancer. Therefore, caution should be taken when FOXO3a is employed as a target for cancer therapy.

Inhibition of Caspase-8 Activity Caused by Overexpression of BCL10 Contributes to the Pathogenesis of High-Grade MALT Lymphoma,

Abstract 3694Mucosa-associated lymphoid tissue (MALT) lymphoma comprises approximately 8% of all non-Hodgkin lymphomas and is the most common lymphoma in the gastrointestinal tract. B-cell lymphoma/leukemia 10 (BCL10) overexpression and nuclear expression has been associated with high-grade MALT lymphomas unresponsive to H. pylori eradication treatment. To explore the molecular mechanism of BCL10 overexpression on the pathogenesis and malignant phenotype of MALT lymphoma, we generated EμSR-BCL10 transgenic mice. Results in our previous report showed that predisposition to marginal zone B-cell lymphoma (MZL) development was enhanced in these transgenic mice. MALT lymphoma precursor cells - marginal zone (MZ) B cells - are expanded in BCL10 transgenic mice. Constitutive activation of both canonical and noncanonical NF-κB pathways was identified in these MZ B cells. Elevated expression of BAFF, a NF-κB downstream gene, may be in part responsible for increased tumor cell survival in MALT lymphomas. In this continuing study, quantitative analysis of BCL10 protein levels and the extent of MZ B cell expansion in heterozygous (Tg/+) and homozygous (Tg/Tg) EμSR-BCL10 transgenic mice demonstrated a direct pathogenic effect of BCL10 protein on MALT lymphomagenesis. The activities of caspase-8 and caspase-3, but not caspase-9, were inhibited with increasing BCL10 protein levels in a dose-dependent manner. Apoptosis induced by anti-IgM was selectively inhibited in MZ B cells from transgenic mice, but no differences were observed following treatment with dexamethasone, γ-irradiation or anti-CD95, implying that overexpressed BCL10 exerts anti-apoptotic effects through the B-cell antigen receptor pathway. Expression of API2, another NF-κB downstream gene, was also elevated in a dose-dependent manner with BCL10 protein level in the MZ B cells. Overexpressed BCL10 protein co-immunoprecipitated with caspase-8 and API2, suggesting an in vivo interaction leading to inhibition of caspase-8 activity. Our current data suggests a novel effect of overexpressed BCL10 in the pathogenesis of high-grade MALT lymphoma by increasing expression of API2 and recruitment of API2 and caspase-8 to form a protein complex leading to the suppression of caspase-8 activity in MZ B cells. Disclosures:No relevant conflicts of interest to declare.

Inhibition of caspase‐8 activity caused by overexpression of bcl10 contributes to the pathogenesis of high‐grade MALT lymphoma

Mucosa-associated lymphoid tissue (MALT) lymphoma comprises approximately 8% of all non-Hodgkin lymphomas and is the most common lymphoma in the gastro-intestinal tract. It is caused by genetic abnormalities or bacterial infections/chronic inflammation. B-cell lymphoma/leukemia 10 (BCL10) overexpression and nuclear expression have been associated with high-grade MALT lymphomas with genetic abnormalities that are unresponsive to Helicobacter pylori eradication treatment. To explore the molecular mechanism of BCL10 overexpression on the pathogenesis and malignant phenotype of MALT lymphoma, we generated EµSR-BCL10 transgenic mice. By generation of heterozygous and homozygous EuSR-BCL10 mice and showing BCL10 expression levels in these mice, we quantitatively examined relation of MZ B cell expansion and inhibition of caspase-8 activity with BCL10 protein level. We also investigated API2 and caspase-8 expression by Western blot and their interaction with BCL10 by co-immunoprecipitation. MZ B-cell expansion is directly related to BCL10 protein level in a dose-dependent manner. The activity of caspases-8 and -3, but not caspase-9, was inhibited with increasing of BCL10 protein level. Expanded MZ B cells showed selective survival under stimulation of anti-immunoglobulin M, but not dexamethasone, γ-irradiation, or anti-CD95, implying that overexpressed BCL10 exerts anti-apoptotic effects through B-cell antigen receptor (BCR) pathway. Overexpressed BCL10 protein co-immunoprecipitated with caspase-8 and API2 protein, suggesting an in vivo interaction of them. Our data demonstrate a novel effect of overexpressed BCL10 in the pathogenesis of high-grade MALT lymphoma by increasing expression of API2 and it then forming a protein complex with BCL10/caspase-8 leading to caspase-8 activity suppression.

Carrageenan-induced innate immune response is modified by enzymes that hydrolyze distinct galactosidic bonds

The common food additive carrageenan (CGN) predictably induces intestinal inflammation in animal models. Mechanisms of CGN-induced nuclear factor κB and interleukin-8 (IL-8) stimulation include an immune-mediated pathway involving toll-like receptor 4 (TLR4) and B-cell lymphoma/leukemia 10 (BCL10) and a reactive oxygen species (ROS)-mediated pathway. To determine how the structure of CGN contributes to its initiation of inflammation through these two distinct mechanisms, we treated CGNs with galactosidases and carrageenases (CGNases) and determined the impact on IL-8 secretion and BCL10 production. Hydrolysis of CGN by the enzyme α-1→(3,6)-galactosidase significantly reduced increases in IL-8 and BCL10, but other galactosidases tested, including α-1→6-galactosidase, β-1→4-galactosidase and β-1→3,6-galactosidase, had no effect. In contrast, specific κ-CGNases or ι-CGNases, which hydrolyze β-1,4-galactosidic bonds, produced increases in IL-8 and BCL10 attributable to increased exposure of the immunogenic α-1→3-galactosidic epitope of CGN to TLR4. These results were consistent with induction of innate immune response by an interaction of TLR4 with the unusual α- d-Gal-(1→3)- d-Gal epitope present in CGN. Activation of the ROS-mediated pathway was unaffected by treatment of κ-CGN with either κ-CGNase (3 mg/L), α-1→(3,6)-galactosidase (20 mU/ml) or these enzymes in combination, indicating that changes in IL-8 production were attributable to the effects of induction of inflammation on the TLR4–BCL10-mediated innate immune pathway. These findings provide new information about the specificity of carbohydrate–protein interaction between CGN and TLR4 and may help to devise treatments that modify the immune reactivity induced by carbohydrate antigens.