RESUMEN
Mucosa-associated lymphoid tissue lymphoma-translocation protein 1 (MALT1) is an attractive target for the development of modulatory compounds in the treatment of lymphoma and other cancers. While the three-dimensional structure of MALT1 has been previously determined through X-ray analysis, its dynamic behaviour in solution has remained unexplored. We present here dynamic analyses of the apo MALT1 form along with the E549A mutation. This investigation used NMR 15N relaxation and NOE measurements between side-chain methyl groups. Our findings confirm that MALT1 exists as a monomer in solution, and demonstrate that the domains display semi-independent movements in relation to each other. Our dynamic study, covering multiple time scales, along with the assessment of conformational populations by Molecular Dynamic simulations, Alpha Fold modelling and PCA analysis, put the side chain of residue W580 in an inward position, shedding light at potential mechanisms underlying the allosteric regulation of this enzyme.
Asunto(s)
Simulación de Dinámica Molecular , Proteína 1 de la Translocación del Linfoma del Tejido Linfático Asociado a Mucosas , Regulación Alostérica , Proteína 1 de la Translocación del Linfoma del Tejido Linfático Asociado a Mucosas/metabolismo , Proteína 1 de la Translocación del Linfoma del Tejido Linfático Asociado a Mucosas/química , Proteína 1 de la Translocación del Linfoma del Tejido Linfático Asociado a Mucosas/genética , Humanos , Espectroscopía de Resonancia Magnética/métodos , Resonancia Magnética Nuclear Biomolecular , Conformación Proteica , MutaciónRESUMEN
MALT1 has been implicated as an upstream regulator of NF-κB signaling in immune cells and tumors. This study determined the regulatory mechanisms and biological functions of MALT1 in non-small cell lung cancer (NSCLC). In cell culture and orthotopic xenograft models, MALT1 suppression via gene expression interference or protein activity inhibition significantly impaired malignant phenotypes and enhanced radiation sensitivity of NSCLC cells. CSN5, the core subunit of COP9 signalosome, was firstly verified to stabilize MALT1 via disturbing the interaction with E3 ligase FBXO3. Loss of FBXO3 in NSCLC cells reduced MALT1 ubiquitination and promoted its accumulation, which was reversed by CSN5 interference. An association between CSN5/FBXO3/MALT1 regulatory axis and poor prognosis in NSCLC patients was identified. Our findings revealed the detail mechanism of continuous MALT1 activation in NF-κB signaling, highlighting its significance as predictor and potential therapeutic target in NSCLC.
Asunto(s)
Complejo del Señalosoma COP9 , Carcinoma de Pulmón de Células no Pequeñas , Neoplasias Pulmonares , Proteína 1 de la Translocación del Linfoma del Tejido Linfático Asociado a Mucosas , FN-kappa B , Transducción de Señal , Proteína 1 de la Translocación del Linfoma del Tejido Linfático Asociado a Mucosas/metabolismo , Proteína 1 de la Translocación del Linfoma del Tejido Linfático Asociado a Mucosas/genética , Carcinoma de Pulmón de Células no Pequeñas/metabolismo , Carcinoma de Pulmón de Células no Pequeñas/patología , Carcinoma de Pulmón de Células no Pequeñas/genética , Humanos , Complejo del Señalosoma COP9/metabolismo , Complejo del Señalosoma COP9/genética , FN-kappa B/metabolismo , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patología , Neoplasias Pulmonares/genética , Animales , Línea Celular Tumoral , Ratones , Ratones Desnudos , Ubiquitinación , Péptido Hidrolasas/metabolismo , Péptido Hidrolasas/genética , Progresión de la Enfermedad , Ratones Endogámicos BALB C , Femenino , Proteínas F-Box/metabolismo , Proteínas F-Box/genética , Péptidos y Proteínas de Señalización IntracelularRESUMEN
CARD-BCL10-MALT1 (CBM) signalosomes connect distal signaling of innate and adaptive immune receptors to proximal signaling pathways and immune activation. Four CARD scaffold proteins (CARD9, 10, 11, 14) can form seeds that nucleate the assembly of BCL10-MALT1 filaments in a cell- and stimulus-specific manner. MALT1 (also known as PCASP1) serves a dual function within the assembled CBM complexes. By recruiting TRAF6, MALT1 acts as a molecular scaffold that initiates IκB kinase (IKK)/NF-κB and c-Jun N-terminal kinase (JNK)/AP-1 signaling. In parallel, proximity-induced dimerization of the paracaspase domain activates the MALT1 protease which exerts its function by cleaving a set of specific substrates. While complete MALT1 ablation leads to immune deficiency, selective destruction of either scaffolding or protease function provokes autoimmune inflammation. Thus, balanced MALT1-TRAF6 recruitment and MALT1 substrate cleavage are critical to maintain immune homeostasis and to promote optimal immune activation. Further, MALT1 protease activity drives the survival of aggressive lymphomas and other non-hematologic solid cancers. However, little is known about the relevance of the cleavage of individual substrates for the pathophysiological functions of MALT1. Unbiased serendipity, screening and computational predictions have identified and validated ~20 substrates, indicating that MALT1 targets a quite distinct set of proteins. Known substrates are involved in CBM auto-regulation (MALT1, BCL10 and CARD10), regulation of signaling and adhesion (A20, CYLD, HOIL-1 and Tensin-3), or transcription (RelB) and mRNA stability/translation (Regnase-1, Roquin-1/2 and N4BP1), indicating that MALT1 often targets multiple proteins involved in similar cellular processes. Here, we will summarize what is known about the fate and functions of individual MALT1 substrates and how their cleavage contributes to the biological functions of the MALT1 protease. We will outline what is needed to better connect critical pathophysiological roles of the MALT1 protease with the cleavage of distinct substrates.
Asunto(s)
Proteína 1 de la Translocación del Linfoma del Tejido Linfático Asociado a Mucosas , Transducción de Señal , Proteína 1 de la Translocación del Linfoma del Tejido Linfático Asociado a Mucosas/metabolismo , Proteína 1 de la Translocación del Linfoma del Tejido Linfático Asociado a Mucosas/genética , Humanos , Animales , Especificidad por Sustrato , Proteína 10 de la LLC-Linfoma de Células B/metabolismo , Proteína 10 de la LLC-Linfoma de Células B/genética , Proteínas Adaptadoras de Señalización CARD/metabolismo , Proteínas Adaptadoras de Señalización CARD/genética , Proteolisis , Factor 6 Asociado a Receptor de TNF/metabolismoRESUMEN
The CARMA-BCL10-MALT1 (CBM) signalosome functions as a pivotal supramolecular module, integrating diverse receptor-induced signaling pathways to regulate BCL10-dependent NF-kB activation in innate and adaptive immunity. Conversely, the API2-MALT1 fusion protein in t(11; 18)(q21; q21) MALT lymphoma constitutively induces BCL10-independent NF-kB activation. MALT1 dimer formation is indispensable for the requisite proteolytic activity and is critical for NF-kB activation regulation in both scenarios. However, the molecular assembly of MALT1 individual domains in CBM activation remains elusive. Here we report the crystal structure of the MALT1 death domain (DD) at a resolution of 2.1 Å, incorporating reconstructed residues in previously disordered loops 1 and 2. Additionally, we observe a conformational regulation element (CRE) regulating stem-helix formation in NLRPs pyrin (PYD) within the MALT1 DD structure. The structure reveals a stem-helix-mediated dimer further corroborated in solution. To elucidate how the BCL10 filament facilitates MALT1 dimerization, we reconstitute a BCL10-CARD-MALT1-DD-IG1-IG2 complex model. We propose a N+7 rule for BCL10-dependent MALT1 dimerization via the IG1-IG2 domain and for MALT1-dependent cleavage in trans. Biochemical data further indicates concentration-dependent dimerization of the MALT1 IG1-IG2 domain, facilitating MALT1 dimerization in BCL10-independent manner. Our findings provide a structural and biochemical foundation for understanding MALT1 dimeric mechanisms, shedding light on potential BCL10-independent MALT1 dimer formation and high-order BCL10-MALT1 assembly.
Asunto(s)
Proteína 10 de la LLC-Linfoma de Células B , Proteína 1 de la Translocación del Linfoma del Tejido Linfático Asociado a Mucosas , Dominios Proteicos , Multimerización de Proteína , Proteína 1 de la Translocación del Linfoma del Tejido Linfático Asociado a Mucosas/metabolismo , Proteína 1 de la Translocación del Linfoma del Tejido Linfático Asociado a Mucosas/química , Proteína 1 de la Translocación del Linfoma del Tejido Linfático Asociado a Mucosas/genética , Proteína 10 de la LLC-Linfoma de Células B/metabolismo , Proteína 10 de la LLC-Linfoma de Células B/química , Proteína 10 de la LLC-Linfoma de Células B/genética , Humanos , Cristalografía por Rayos X , Modelos Moleculares , Proteínas de Neoplasias/metabolismo , Proteínas de Neoplasias/química , Proteínas de Neoplasias/genética , Caspasas/metabolismo , Caspasas/químicaRESUMEN
The objective of this study was to clarify the long-term prognosis of patients with gastric mucosa-associated lymphoid tissue (MALT) lymphoma with additional copies of MALT1. In this multicenter retrospective study, we enrolled 145 patients with gastric MALT lymphoma who underwent fluorescence in situ hybridization (FISH) analysis to detect t(11;18) translocation. The patient cohort was divided into three groups: Group A (n = 87), comprising individuals devoid of the t(11;18) translocation or extra MALT1 copies; Group B (n = 27), encompassing patients characterized by the presence of the t(11;18) translocation; and Group C (n = 31), including patients with extra MALT1 copies. The clinical outcomes in each cohort were collected. Over the course of a mean follow-up of 8.5 ± 4.2 years, one patient died of progressive MALT lymphoma, while 15 patients died due to etiologies unrelated to lymphoma. The progression or relapse of MALT lymphoma was observed in 11 patients: three in Group A, two in Group B, and six in Group C. In Groups A, B, and C, the 10-year overall survival rates were 82.5%, 93.8%, and 86.4%, respectively, and the 10-year event-free survival rates were 96.1%, 96.0%, and 82.9%, respectively. The event-free survival rate in Group C was significantly lower than that in Group A. However, no differences were observed in the 10-year event-free survival rates among individuals limited to stage I or II1 disease (equivalent to excluding patients with stage IV disease in this study, as there were no patients with stage II2), with rates of 98.6%, 95.8%, and 92.3% for Groups A, B, and C, respectively. In conclusion, the presence of extra copies of MALT1 was identified as an inferior prognostic determinant of event-free survival. Consequently, trisomy/tetrasomy 18 may serve as an indicator of progression and refractoriness to therapeutic intervention in patients with gastric MALT lymphoma, particularly stage IV gastric MALT lymphoma.
Asunto(s)
Linfoma de Células B de la Zona Marginal , Linfoma no Hodgkin , Neoplasias Gástricas , Humanos , Linfoma de Células B de la Zona Marginal/genética , Linfoma de Células B de la Zona Marginal/patología , Hibridación Fluorescente in Situ , Estudios Retrospectivos , Recurrencia Local de Neoplasia/genética , Translocación Genética , Proteína 1 de la Translocación del Linfoma del Tejido Linfático Asociado a Mucosas/genéticaRESUMEN
The protease MALT1 promotes lymphocyte activation and lymphomagenesis by cleaving a limited set of cellular substrates, most of which control gene expression. Here, we identified the integrin-binding scaffold protein Tensin-3 as a MALT1 substrate in activated human B cells. Activated B cells lacking Tensin-3 showed decreased integrin-dependent adhesion but exhibited comparable NF-κB1 and Jun N-terminal kinase transcriptional responses. Cells expressing a noncleavable form of Tensin-3, on the other hand, showed increased adhesion. To test the role of Tensin-3 cleavage in vivo, mice expressing a noncleavable version of Tensin-3 were generated, which showed a partial reduction in the T cell-dependent B cell response. Interestingly, human diffuse large B cell lymphomas and mantle cell lymphomas with constitutive MALT1 activity showed strong constitutive Tensin-3 cleavage and a decrease in uncleaved Tensin-3 levels. Moreover, silencing of Tensin-3 expression in MALT1-driven lymphoma promoted dissemination of xenografted lymphoma cells to the bone marrow and spleen. Thus, MALT1-dependent Tensin-3 cleavage reveals a unique aspect of the function of MALT1, which negatively regulates integrin-dependent B cell adhesion and facilitates metastatic spread of B cell lymphomas.
Asunto(s)
Caspasas , Linfoma de Células B Grandes Difuso , Ratones , Humanos , Animales , Adulto , Tensinas/genética , Caspasas/metabolismo , FN-kappa B/metabolismo , Adhesión Celular/genética , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , Proteína 1 de la Translocación del Linfoma del Tejido Linfático Asociado a Mucosas/genética , Proteína 1 de la Translocación del Linfoma del Tejido Linfático Asociado a Mucosas/metabolismo , Linfoma de Células B Grandes Difuso/genética , IntegrinasRESUMEN
MALT1 (mucosa-associated lymphoid tissue lymphoma translocation protein 1) serves as a pivotal mediator for NF-κB activation in response to a wide spectrum of transmembrane receptor stimuli. In the present study, a homolog of MALT1, named LvMALT1, is cloned from the Pacific white shrimp (Litopenaeus vannamei) and its potential function in shrimp innate immunity is explored. The open reading frame of LvMALT1 is 2364 bp that encodes 787 amino acids. The predicted LvMALT1 protein structure comprises a death domain, three immunoglobulin domains, and a caspase-like domain, exhibiting remarkable similarity to other homologs. LvMALT1 is a cytoplasmic-localized protein and could interact with LvTRAF6. Overexpression of LvMALT1 induces the activation of promoter elements governing the expression of several key antimicrobial peptides (AMPs), including penaeidins (PENs) and crustins (CRUs). Conversely, silencing of LvMALT1 leads to a reduction in the phosphorylation levels of Dorsal and Relish, along with a concomitant decline in the in vivo expression levels of multiple AMPs. Furthermore, LvMALT1 is prominently upregulated in response to a challenge by the white spot syndrome virus (WSSV), facilitating the NF-κB-mediated expression of AMPs as a defense against viral infection. Taken together, we identified a MALT1 homolog from the shrimp L. vannamei, which plays a positive role in the TRAF6/NF-κB/AMPs axis-mediated innate immunity.
Asunto(s)
Virosis , Virus del Síndrome de la Mancha Blanca 1 , Humanos , FN-kappa B/metabolismo , Transducción de Señal , Regiones Promotoras Genéticas , Regulación de la Expresión Génica , Virus del Síndrome de la Mancha Blanca 1/genética , Inmunidad Innata , Proteína 1 de la Translocación del Linfoma del Tejido Linfático Asociado a Mucosas/genética , Proteína 1 de la Translocación del Linfoma del Tejido Linfático Asociado a Mucosas/metabolismoRESUMEN
It is widely accepted that pancreatic islet ß-cell failure and the onset of type 2 diabetes (T2DM) constitute an intricate interplay between the genetic expression of the disease and a host of intracellular events including increased metabolic (oxidative, endoplasmic reticulum) stress under the duress of glucolipotoxicity. Emerging evidence implicates unique roles for Caspase Recruitment Domain containing protein 9 (CARD9) in the onset of metabolic diseases, including obesity and insulin resistance. Mechanistically, CARD9 has been implicated in the regulation of p38MAPK and NFkB signaling pathways culminating in cellular dysfunction. Several regulatory factors, including B-cell lymphoma/leukemia 10 (BCL10) have been identified as modulators of CARD9 function in multiple cell types. Despite this evidence on regulatory roles of CARD9-BCL10 signalome in the onset of various pathological states, putative roles of this signaling module in islet ß-cell dysfunction in metabolic stress remain less understood. This brief review is aimed at highlighting roles for CARD9 in islet ß-cell function under acute (physiological insulin secretion) and long-term (cell dysfunction) exposure to glucose. Emerging roles of other signaling proteins, such as Rac1, BCL10 and MALT1 as contributors to CARD9 signaling in the islet ß-cells are also reviewed. Potential avenues for future research toward the development of novel therapeutics for the prevention CARD9-BCL10-Rac1 (CBR) signalome-induced ß-cell defects under metabolic stress are discussed.
Asunto(s)
Diabetes Mellitus Tipo 2 , Islotes Pancreáticos , Humanos , Proteína 10 de la LLC-Linfoma de Células B/genética , Proteínas Adaptadoras de Señalización CARD/genética , Proteína 1 de la Translocación del Linfoma del Tejido Linfático Asociado a Mucosas/genética , Proteínas , Transducción de Señal , Estrés FisiológicoRESUMEN
Constitutive activation of the MALT1 paracaspase in conventional T cells of Malt1TBM/TBM (TRAF6 Binding Mutant = TBM) mice causes fatal inflammation and autoimmunity, but the involved targets and underlying molecular mechanisms are unknown. We genetically rendered a single MALT1 substrate, the RNA-binding protein (RBP) Roquin-1, insensitive to MALT1 cleavage. These Rc3h1Mins/Mins mice showed normal immune homeostasis. Combining Rc3h1Mins/Mins alleles with those encoding for constitutively active MALT1 (TBM) prevented spontaneous T cell activation and restored viability of Malt1TBM/TBM mice. Mechanistically, we show how antigen/MHC recognition is translated by MALT1 into Roquin cleavage and derepression of Roquin targets. Increasing T cell receptor (TCR) signals inactivated Roquin more effectively, and only high TCR strength enabled derepression of high-affinity targets to promote Th17 differentiation. Induction of experimental autoimmune encephalomyelitis (EAE) revealed increased cleavage of Roquin-1 in disease-associated Th17 compared to Th1 cells in the CNS. T cells from Rc3h1Mins/Mins mice did not efficiently induce the high-affinity Roquin-1 target IκBNS in response to TCR stimulation, showed reduced Th17 differentiation, and Rc3h1Mins/Mins mice were protected from EAE. These data demonstrate how TCR signaling and MALT1 activation utilize graded cleavage of Roquin to differentially regulate target mRNAs that control T cell activation and differentiation as well as the development of autoimmunity.
Asunto(s)
Autoinmunidad , Encefalomielitis Autoinmune Experimental , Ratones , Animales , Proteína 1 de la Translocación del Linfoma del Tejido Linfático Asociado a Mucosas/genética , Inflamación/metabolismo , Diferenciación Celular , Encefalomielitis Autoinmune Experimental/genética , Receptores de Antígenos de Linfocitos T/genética , Ubiquitina-Proteína LigasasRESUMEN
Constitutive mucosa-associated lymphoid tissue lymphoma translocation protein 1 (MALT1) activity drives survival of malignant lymphomas addicted to chronic B-cell receptor signaling, oncogenic CARD11, or the API2-MALT1 (also BIRC3::MALT1) fusion oncoprotein. Although MALT1 scaffolding induces NF-κB-dependent survival signaling, MALT1 protease function is thought to augment NF-κB activation by cleaving signaling mediators and transcriptional regulators in B-cell lymphomas. However, the pathological role of MALT1 protease function in lymphomagenesis is not well understood. Here, we show that TRAF6 controls MALT1-dependent activation of NF-κB transcriptional responses but is dispensable for MALT1 protease activation driven by oncogenic CARD11. To uncouple enzymatic and nonenzymatic functions of MALT1, we analyzed TRAF6-dependent and -independent as well as MALT1 protease-dependent gene expression profiles downstream of oncogenic CARD11 and API2-MALT1. The data suggest that by cleaving and inactivating the RNA binding proteins Regnase-1 and Roquin-1/2, MALT1 protease induces posttranscriptional upregulation of many genes including NFKBIZ/IκBζ, NFKBID/IκBNS, and ZC3H12A/Regnase-1 in activated B-cell-like diffuse large B-cell lymphoma (ABC DLBCL). We demonstrate that oncogene-driven MALT1 activity in ABC DLBCL cells regulates NFKBIZ and NFKBID induction on an mRNA level via releasing a brake imposed by Regnase-1 and Roquin-1/2. Furthermore, MALT1 protease drives posttranscriptional gene induction in the context of the API2-MALT1 fusion created by the recurrent t(11;18)(q21;q21) translocation in MALT lymphoma. Thus, MALT1 paracaspase acts as a bifurcation point for enhancing transcriptional and posttranscriptional gene expression in malignant lymphomas. Moreover, the identification of MALT1 protease-selective target genes provides specific biomarkers for the clinical evaluation of MALT1 inhibitors.
Asunto(s)
Linfoma de Células B de la Zona Marginal , Linfoma de Células B Grandes Difuso , Humanos , Proteína 1 de la Translocación del Linfoma del Tejido Linfático Asociado a Mucosas/genética , FN-kappa B/genética , FN-kappa B/metabolismo , Factor 6 Asociado a Receptor de TNF/genética , Oncogenes , Linfoma de Células B de la Zona Marginal/genética , Linfoma de Células B de la Zona Marginal/metabolismo , Linfoma de Células B Grandes Difuso/patología , Proteínas de Fusión Oncogénica/genética , Proteínas de Fusión Oncogénica/metabolismoRESUMEN
Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer and the third leading cause of cancer-related deaths worldwide. Despite recent advances in treatment options, therapeutic management of HCC remains a challenge, emphasizing the importance of exploring novel targets. MALT1 paracaspase is a druggable signaling molecule whose dysregulation has been linked to hematological and solid tumors. However, the role of MALT1 in HCC remains poorly understood, leaving its molecular functions and oncogenic implications unclear. Here we provide evidence that MALT1 expression is elevated in human HCC tumors and cell lines, and that correlates with tumor grade and differentiation state, respectively. Our results indicate that ectopic expression of MALT1 confers increased cell proliferation, 2D clonogenic growth, and 3D spheroid formation in well differentiated HCC cell lines with relatively low MALT1 levels. In contrast, stable silencing of endogenous MALT1 through RNA interference attenuates these aggressive cancer cell phenotypes, as well as migration, invasion, and tumor-forming ability, in poorly differentiated HCC cell lines with higher paracaspase expression. Consistently, we find that pharmacological inhibition of MALT1 proteolytic activity with MI-2 recapitulates MALT1 depletion phenotypes. Finally, we show that MALT1 expression is positively correlated with NF-kB activation in human HCC tissues and cell lines, suggesting that its tumor promoting functions may involve functional interaction with the NF-kB signaling pathway. This work unveils new insights into the molecular implications of MALT1 in hepatocarcinogenesis and places this paracaspase as a potential marker and druggable liability in HCC.
Asunto(s)
Carcinoma Hepatocelular , Neoplasias Hepáticas , Humanos , Proteína 1 de la Translocación del Linfoma del Tejido Linfático Asociado a Mucosas/genética , Proteína 1 de la Translocación del Linfoma del Tejido Linfático Asociado a Mucosas/metabolismo , Carcinoma Hepatocelular/genética , FN-kappa B/metabolismo , Caspasas/metabolismo , Supervivencia Celular , Neoplasias Hepáticas/genéticaRESUMEN
The paracaspase MALT1 is a crucial regulator of immune responses in various cellular contexts. Recently, there is increasing evidence suggesting that MALT1 might represent a novel key player in mucosal inflammation. However, the molecular mechanisms underlying this process and the targeted cell population remain unclear. In this study, we investigate the role of MALT1 proteolytic activity in the context of mucosal inflammation. We demonstrate a significant enrichment of MALT1 gene and protein expression in colonic epithelial cells of UC patients, as well as in the context of experimental colitis. Mechanistically we demonstrate that MALT1 protease function inhibits ferroptosis, a form of iron-dependent cell death, upstream of NF-κB signaling, which can promote inflammation and tissue damage in IBD. We further show that MALT1 activity contributes to STAT3 signaling, which is essential for the regeneration of the intestinal epithelium after injury. In summary, our data strongly suggests that the protease function of MALT1 plays a critical role in the regulation of immune and inflammatory responses, as well as mucosal healing. Understanding the mechanisms by which MALT1 protease function regulates these processes may offer novel therapeutic targets for the treatment of IBD and other inflammatory diseases.
Asunto(s)
Enfermedades Inflamatorias del Intestino , Transducción de Señal , Humanos , Inflamación , Enfermedades Inflamatorias del Intestino/genética , Proteína 1 de la Translocación del Linfoma del Tejido Linfático Asociado a Mucosas/genética , Proteína 1 de la Translocación del Linfoma del Tejido Linfático Asociado a Mucosas/metabolismo , FN-kappa B/metabolismo , Proteolisis , Células EpitelialesRESUMEN
The paracaspase mucosa-associated lymphoid tissue 1 (MALT1) is a protease and scaffold protein essential in propagating B-cell receptor (BCR) signaling to NF-κB. The deubiquitinating enzyme cylindromatosis (CYLD) is a recently discovered MALT1 target that can negatively regulate NF-κB activation. Here, we show that low expression of CYLD is associated with inferior prognosis of diffuse large B-cell lymphoma (DLBCL) and mantle cell lymphoma (MCL) patients, and that chronic BCR signaling propagates MALT1-mediated cleavage and, consequently, inactivation and rapid proteasomal degradation of CYLD. Ectopic overexpression of WT CYLD or a MALT1-cleavage resistant mutant of CYLD reduced phosphorylation of IκBα, repressed transcription of canonical NF-κB target genes and impaired growth of BCR-dependent lymphoma cell lines. Furthermore, silencing of CYLD expression rendered BCR-dependent lymphoma cell lines less sensitive to inhibition of NF-κΒ signaling and cell proliferation by BCR pathway inhibitors, e.g., the BTK inhibitor ibrutinib, indicating that these effects are partially mediated by CYLD. Taken together, our findings identify an important role for MALT1-mediated CYLD cleavage in BCR signaling, NF-κB activation and cell proliferation, which provides novel insights into the underlying molecular mechanisms and clinical potential of inhibitors of MALT1 and ubiquitination enzymes as promising therapeutics for DLBCL, MCL and potentially other B-cell malignancies.
Asunto(s)
Enzima Desubiquitinante CYLD , Linfoma de Células B Grandes Difuso , Proteína 1 de la Translocación del Linfoma del Tejido Linfático Asociado a Mucosas , FN-kappa B , Humanos , Caspasas/metabolismo , Enzima Desubiquitinante CYLD/genética , Enzima Desubiquitinante CYLD/metabolismo , Linfoma de Células B Grandes Difuso/patología , Proteína 1 de la Translocación del Linfoma del Tejido Linfático Asociado a Mucosas/genética , Proteína 1 de la Translocación del Linfoma del Tejido Linfático Asociado a Mucosas/metabolismo , FN-kappa B/metabolismo , Receptores de Antígenos de Linfocitos B , Transducción de Señal/fisiologíaRESUMEN
Bruton's tyrosine kinase (BTK) is a proven target in mantle cell lymphoma (MCL), an aggressive subtype of non-Hodgkin lymphoma. However, resistance to BTK inhibitors is a major clinical challenge. We here report that MALT1 is one of the top overexpressed genes in ibrutinib-resistant MCL cells, while expression of CARD11, which is upstream of MALT1, is decreased. MALT1 genetic knockout or inhibition produced dramatic defects in MCL cell growth regardless of ibrutinib sensitivity. Conversely, CARD11-knockout cells showed antitumor effects only in ibrutinib-sensitive cells, suggesting that MALT1 overexpression could drive ibrutinib resistance via bypassing BTK/CARD11 signaling. Additionally, BTK knockdown and MALT1 knockout markedly impaired MCL tumor migration and dissemination, and MALT1 pharmacological inhibition decreased MCL cell viability, adhesion, and migration by suppressing NF-κB, PI3K/AKT/mTOR, and integrin signaling. Importantly, cotargeting MALT1 with safimaltib and BTK with pirtobrutinib induced potent anti-MCL activity in ibrutinib-resistant MCL cell lines and patient-derived xenografts. Therefore, we conclude that MALT1 overexpression associates with resistance to BTK inhibitors in MCL, targeting abnormal MALT1 activity could be a promising therapeutic strategy to overcome BTK inhibitor resistance, and cotargeting of MALT1 and BTK should improve MCL treatment efficacy and durability as well as patient outcomes.
Asunto(s)
Linfoma de Células del Manto , Proteínas Tirosina Quinasas , Humanos , Adulto , Agammaglobulinemia Tirosina Quinasa/genética , Proteínas Tirosina Quinasas/metabolismo , Linfoma de Células del Manto/tratamiento farmacológico , Linfoma de Células del Manto/genética , Línea Celular Tumoral , Fosfatidilinositol 3-Quinasas , Resistencia a Antineoplásicos/genética , Inhibidores de Proteínas Quinasas/farmacología , Inhibidores de Proteínas Quinasas/uso terapéutico , Proteína 1 de la Translocación del Linfoma del Tejido Linfático Asociado a Mucosas/genéticaRESUMEN
A 68-year-old man was admitted because of a left shoulder mass and swollen right testis. Pathological examinations indicated a diagnosis of diffuse large B-cell lymphoma (DLBCL) with the CD20+BCL6+MUM1+BCL2+CD10-MYC- phenotype in both lesions. G-banding of soft tissue showed 47,XY,+18, whereas testicular cells showed 47,X,+X,-Y,der (4) t (4;18) (p15;?),del (5) (q?),+13. Fluorescence in situ hybridization detected additional MALT1 and BCL2 signals in both lesions. Southern blot demonstrated different IGH rearrangements between the soft tissue and testis. The patient was diagnosed with biclonal DLBCL with different karyotypes but similar immunophenotypes. Partial trisomy 18q involving MALT1 and BCL2 may be commonly involved in the pathogenesis of this biclonal DLBCL.
Asunto(s)
Linfoma de Células B Grandes Difuso , Trisomía , Masculino , Humanos , Trisomía/genética , Translocación Genética , Hibridación Fluorescente in Situ , Linfoma de Células B Grandes Difuso/genética , Linfoma de Células B Grandes Difuso/patología , Proteínas Proto-Oncogénicas c-bcl-2/genética , Proteína 1 de la Translocación del Linfoma del Tejido Linfático Asociado a Mucosas/genéticaRESUMEN
The uniqueness of MALT1 protease activity in controlling several aspects of immunity in humans has made it a very attractive therapeutic target for multiple autoimmune diseases and lymphoid malignancies. Despite several encouraging preclinical studies with MALT1 inhibitors, severe reduction in regulatory T cells and immune-mediated pathology seen in MALT1 protease-dead (MALT1-PD) mice and some, but not all, studies analysing the effect of prolonged pharmacological MALT1 protease inhibition, indicates the need to further unravel the mechanism of MALT1 protease function. Notably, the contribution of individual MALT1 substrates to the immune defects seen in MALT1-PD mice is still unclear. Previous in vitro studies indicated a role for MALT1-mediated cleavage of the E3 ubiquitin ligase HOIL-1 in the modulation of nuclear factor-κB (NF-κB) signalling and inflammatory gene expression in lymphocytes. Here, we addressed the immunological consequences of inhibition of HOIL-1 cleavage by generating and immunophenotyping MALT1 cleavage-resistant HOIL-1 knock-in (KI) mice. HOIL-1 KI mice appear healthy and have no overt phenotype. NF-κB activation in T or B cells, as well as IL-2 production and in vitro T-cell proliferation, is comparable between control and HOIL-1 KI cells. Inhibition of HOIL-1 cleavage in mice has no effect on thymic T-cell development and conventional T-cell homeostasis. Likewise, B-cell development and humoral immune responses are not affected. Together, these data exclude an important role of MALT1-mediated HOIL-1 cleavage in T- and B-cell development and function in mice.
Asunto(s)
Caspasas , FN-kappa B , Animales , Humanos , Ratones , Caspasas/metabolismo , Homeostasis , Activación de Linfocitos , Linfocitos/metabolismo , Proteína 1 de la Translocación del Linfoma del Tejido Linfático Asociado a Mucosas/genética , Proteína 1 de la Translocación del Linfoma del Tejido Linfático Asociado a Mucosas/metabolismo , FN-kappa B/metabolismo , Ubiquitina-Proteína Ligasas/metabolismoRESUMEN
Objective: MALT1 regulates immunity and inflammation in multiple ways, while its role in rheumatoid arthritis (RA) is obscure. This study aimed to investigate the relationship of MALT1 with disease features, treatment outcome, as well as its effect on Th1/2/17 cell differentiation and underlying molecule mechanism in RA. Methods: Totally 147 RA patients were enrolled. Then their blood Th1, Th2, and Th17 cells were detected by flow cytometry. Besides, PBMC MALT1 expression was detected before treatment (baseline), at week (W) 6, W12, and W24. PBMC MALT1 in 30 osteoarthritis patients and 30 health controls were also detected. Then, blood CD4+ T cells were isolated from RA patients, followed by MALT1 overexpression or knockdown lentivirus transfection and Th1/2/17 polarization assay. In addition, IMD 0354 (NF-κB antagonist) and SP600125 (JNK antagonist) were also added to treat CD4+ T cells. Results: MALT1 was increased in RA patients compared to osteoarthritis patients and healthy controls. Meanwhile, MALT1 positively related to CRP, ESR, DAS28 score, Th17 cells, negatively linked with Th2 cells, but did not link with other features or Th1 cells in RA patients. Notably, MALT1 decreased longitudinally during treatment, whose decrement correlated with RA treatment outcome (treatment response, low disease activity, or disease remission). In addition, MALT1 overexpression promoted Th17 differentiation, inhibited Th2 differentiation, less affected Th1 differentiation, activated NF-κB and JNK pathways in RA CD4+ T cells; while MALT1 knockdown exhibited the opposite effect. Besides, IMD 0354 and SP600125 addition attenuated MALT1's effect on Th2 and Th17 differentiation. Conclusion: MALT1 regulates Th2 and Th17 differentiation via NF-κB and JNK pathways, as well as correlates with disease activity and treatment outcome in RA.
Asunto(s)
Artritis Reumatoide , Proteína 1 de la Translocación del Linfoma del Tejido Linfático Asociado a Mucosas , FN-kappa B , Osteoartritis , Artritis Reumatoide/tratamiento farmacológico , Artritis Reumatoide/genética , Artritis Reumatoide/inmunología , Diferenciación Celular , Humanos , Leucocitos Mononucleares/inmunología , Sistema de Señalización de MAP Quinasas/inmunología , Proteína 1 de la Translocación del Linfoma del Tejido Linfático Asociado a Mucosas/genética , Proteína 1 de la Translocación del Linfoma del Tejido Linfático Asociado a Mucosas/inmunología , FN-kappa B/genética , FN-kappa B/inmunología , Osteoartritis/metabolismo , Células Th17/inmunología , Células Th2/inmunología , Resultado del TratamientoRESUMEN
Alternative splicing plays key roles for cell type-specific regulation of protein function. It is controlled by cis-regulatory RNA elements that are recognized by RNA binding proteins (RBPs). The MALT1 paracaspase is a key factor of signaling pathways that mediate innate and adaptive immune responses. Alternative splicing of MALT1 is critical for controlling optimal T cell activation. We demonstrate that MALT1 splicing depends on RNA structural elements that sequester the splice sites of the alternatively spliced exon7. The RBPs hnRNP U and hnRNP L bind competitively to stem-loop RNA structures that involve the 5' and 3' splice sites flanking exon7. While hnRNP U stabilizes RNA stem-loop conformations that maintain exon7 skipping, hnRNP L disrupts these RNA elements to facilitate recruitment of the essential splicing factor U2AF2, thereby promoting exon7 inclusion. Our data represent a paradigm for the control of splice site selection by differential RBP binding and modulation of pre-mRNA structure.
Asunto(s)
Ribonucleoproteína Heterogénea-Nuclear Grupo L , Precursores del ARN , Empalme Alternativo , Sitios de Unión , Exones , Ribonucleoproteína Heterogénea-Nuclear Grupo L/genética , Ribonucleoproteína Heterogénea-Nuclear Grupo L/metabolismo , Ribonucleoproteína Heterogénea-Nuclear Grupo U/genética , Ribonucleoproteína Heterogénea-Nuclear Grupo U/metabolismo , Ribonucleoproteínas Nucleares Heterogéneas/genética , Ribonucleoproteínas Nucleares Heterogéneas/metabolismo , Proteína 1 de la Translocación del Linfoma del Tejido Linfático Asociado a Mucosas/genética , Proteína 1 de la Translocación del Linfoma del Tejido Linfático Asociado a Mucosas/metabolismo , Precursores del ARN/genética , Sitios de Empalme de ARN , Proteínas de Unión al ARN/genética , Proteínas de Unión al ARN/metabolismoRESUMEN
Deep vein thrombosis (DVT) is the third most common cause of cardiovascular mortality. Several studies suggest that DVT occurs at the intersection of dysregulated inflammation and coagulation upon activation of inflammasome and secretion of interleukin 1ß (IL-1ß) in restricted venous flow conditions. Our recent studies showed a signaling adapter protein, Gab2 (Grb2-associated binder 2), plays a crucial role in propagating inflammatory signaling triggered by IL-1ß and other inflammatory mediators in endothelial cells. The present study shows that Gab2 facilitates the assembly of the CBM (CARMA3 [CARD recruited membrane-associated guanylate kinase protein 3]-BCL-10 [B-cell lymphoma 10]-MALT1 [mucosa-associated lymphoid tissue lymphoma translocation protein 1]) signalosome, which mediates the activation of Rho and NF-κB in endothelial cells. Gene silencing of Gab2 or MALT1, the effector signaling molecule in the CBM signalosome, or pharmacological inhibition of MALT1 with a specific inhibitor, mepazine, significantly reduced IL-1ß-induced Rho-dependent exocytosis of P-selectin and von Willebrand factor (VWF) and the subsequent adhesion of neutrophils to endothelial cells. MALT1 inhibition also reduced IL-1ß-induced NF-κB-dependent expression of tissue factor and vascular cell adhesion molecule 1. Consistent with the in vitro data, Gab2 deficiency or pharmacological inhibition of MALT1 suppressed the accumulation of monocytes and neutrophils at the injury site and attenuated venous thrombosis induced by the inferior vena cava ligation-induced stenosis or stasis in mice. Overall, our data reveal a previously unrecognized role of the Gab2-MALT1 axis in thromboinflammation. Targeting the Gab2-MALT1 axis with MALT1 inhibitors may become an effective strategy to treat DVT by suppressing thromboinflammation without inducing bleeding complications.