Project description:Proper regulation of nuclear factor κB (NF-κB) transcriptional activity is required for normal lymphocyte function, and deregulated NF-κB signaling can facilitate lymphomagenesis. We demonstrate that the API2-MALT1 fusion oncoprotein created by the recurrent t(11;18)(q21;q21) in mucosa-associated lymphoid tissue (MALT) lymphoma induces proteolytic cleavage of NF-κB–inducing kinase (NIK) at arginine 325. NIK cleavage requires the concerted actions of both fusion partners and generates a C-terminal NIK fragment that retains kinase activity and is resistant to proteasomal degradation. The resulting deregulated NIK activity is associated with constitutive noncanonical NF-κB signaling, enhanced B cell adhesion, and apoptosis resistance. Our study reveals the gain-of-function proteolytic activity of a fusion oncoprotein and highlights the importance of the noncanonical NF-κB pathway in B lymphoproliferative disease.
Project description:Proper regulation of nuclear factor κB (NF-κB) transcriptional activity is required for normal lymphocyte function, and deregulated NF-κB signaling can facilitate lymphomagenesis. We demonstrate that the API2-MALT1 fusion oncoprotein created by the recurrent t(11;18)(q21;q21) in mucosa-associated lymphoid tissue (MALT) lymphoma induces proteolytic cleavage of NF-κB–inducing kinase (NIK) at arginine 325. NIK cleavage requires the concerted actions of both fusion partners and generates a C-terminal NIK fragment that retains kinase activity and is resistant to proteasomal degradation. The resulting deregulated NIK activity is associated with constitutive noncanonical NF-κB signaling, enhanced B cell adhesion, and apoptosis resistance. Our study reveals the gain-of-function proteolytic activity of a fusion oncoprotein and highlights the importance of the noncanonical NF-κB pathway in B lymphoproliferative disease. This study compares nine t(11;18)-positive MALT lymphomas (8 from the stomach and 1 from lung) and eight translocation negative MALT lymphomas (all from the stomach) using gene set enrichment analysis (GSEA). All cases were subjected to Affymetrix U133A and U133B microarray analysis. The cases used in this study are the same cases used for the study by Hamoudi et al. (2010) entitled "Differential expression of NF-kB target genes in MALT lymphoma with and without chromosome translocation: insights into molecular mechanism" with GEO reference number: GSE18736 and PubMed ID: http://www.ncbi.nlm.nih.gov/pubmed/20520640 All cases were subjected to non-specific filtering to eliminate non-variant probes, then the U133A and U133B probes were collapsed and the collapsed set was subjected to GSEA using the NF-kB target gene set as described in Hamoudi et al. (2010) study mentioned above. The 34 samples in this study are identical to the ones done in the previous series except that the gene set enrichment was done on just those 34 samples and not the complete set.
Project description:Constitutive MALT1 activity drives survival of malignant lymphomas addicted to chronic B-cell receptor (BCR) signaling, oncogenic CARD11, or the API2-MALT1 fusion oncoprotein. While MALT1 scaffolding induces NF-kB-dependent survival signaling, MALT1 protease function is thought to augment NF-kB 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-kB transcriptional responses, but is dispensable for MALT1 protease activation driven by oncogenic CARD11. To uncouple enzymatic and non-enzymatic 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. By cleaving and inactivating the RNA binding proteins Regnase-1 and Roquin-1/2, MALT1 protease induces post-transcriptional upregulation of genes like NFKBIZ/IkBz, NFKBID/IkBNS 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 mRNA level via releasing a brake imposed by Regnase-1 and Roquin-1/2. Furthermore, MALT1 protease drives post-transcriptional gene induction in the context of the API2-MALT1 fusion created by the recurrent t(11;18)(q21;q21) translocation in mucosa-associated lymphoid tissue (MALT) lymphoma. Thus, MALT1 paracaspase acts as a bifurcation point for enhancing transcriptional and post-transcriptional gene expression in malignant lymphomas. Moreover, the identification of MALT1 protease selective target genes will provides specific biomarkers for the clinical evaluation of MALT1 inhibitors.
Project description:Purpose: study the role of MALT1 auto-proteolysis in T cell receptor mediated activation of NF-kB. Methods: Jurkat cells were generated that express wild type MALT1, the auto-cleavage deficient MALT1-R149A mutant, the catalytic inactive MALT1-C464A mutant or the R149A-C464A double mutant (RACA). Expression of endogenous MALT1 was inactivated using TALEN technology for the Jurkat cells expressing MALT1-R149A (JDM-RA) and MALT1-C464A (JDM-CA). Illumina HISeq 2000 deep sequencing was performed to determine the mRNA profiles for MALT1, JDM-RA, JDM-CA and RACA cells in unstimulated conditions or after treatment with 75ng/ml PMA and 150 ng/ml ionomycin for 3 or 18 hrs. Results: PMA ionomycin stimulation of the MALT1 auto-cleavage defective JDM-RA cells fails to activate NF-kB-dependent transcription like for the MALT1 catalytic inactive JDM-CA cells and the double RACA mutant cells. Conclusion: MALT1 autoproteolysis is essential for transcription of NF-kB target genes
Project description:Microarrays were used to examine gene expression changes at two time points following the induction of differentiation of Malt1 deficient Naive T cells into Th1 or Th17 cells. The present study aims to find the effect that Malt1 deficiency has on lineage specific T cell differentiation. Malt1 is a NF kappa B regulator and plays a key role in peripheral T cell activation and proliferation, but its role in T cell differentiation is not clear. Aspects of the latter are what the current data set investigates. Total RNA obtained from naïve T cells at two time points following induction to lineage specific T helper cells.
Project description:Microarrays were used to examine gene expression changes at two time points following the induction of differentiation of Malt1 deficient Naive T cells into Th1 or Th17 cells. The present study aims to find the effect that Malt1 deficiency has on lineage specific T cell differentiation. Malt1 is a NF kappa B regulator and plays a key role in peripheral T cell activation and proliferation, but its role in T cell differentiation is not clear. Aspects of the latter are what the current data set investigates.
Project description:The NF-κB pathway is a master regulator of inflammatory processes and is implicated in insulin resistance and pancreatic beta cell dysfunction in the metabolic syndrome. While canonical NF-κB signaling is well studied, there is little information on the divergent non-canonical NF-κB pathway in the context of pancreatic islet dysfunction in diabetes. Here, we demonstrate that pharmacological activation of the non-canonical NF-κB inducing kinase (NIK) disrupts glucose homeostasis in zebrafish in vivo. Further, we identify NIK as a critical negative regulator of beta cell function as pharmacological NIK activation results in impaired glucose-stimulated insulin secretion in mouse and human islets. NIK levels are elevated in pancreatic islets isolated from diet-induced obese (DIO) mice, which exhibit increased processing of non-canonical NF-κB components p100 to p52, and accumulation of RelB. Tumor necrosis factor α (TNFα) and receptor activator of NF-κB ligand (RANKL), two ligands associated with diabetes, induce NIK in islets. Mice with constitutive beta cell intrinsic NIK activation present impaired insulin secretion with DIO. NIK activation triggers the non-canonical NF-κB transcriptional network to induce genes identified in human type 2 diabetes genome-wide association studies linked to beta cell failure. These studies reveal that NIK contributes a central mechanism for beta cell failure in diet-induced obesity. We identify a role for Nuclear Factor inducing κB (NIK) in pancreatic beta cell failure. NIK activation disrupts glucose homeostasis in zebrafish in vivo and impairs glucose-stimulated insulin secretion in mouse and human islets in vitro. NIK activation also perturbs beta cell insulin secretion in a diet-induced obesity mouse model. These studies reveal that NIK contributes a central mechanism for beta cell failure in obesity. To uncover the role of NIK in pancreatic beta cells, we performed a gene expression microarray analysis comparing pancreatic islets with constitutive beta cell intrinsicNIK activation from the 16 week old mice (beta cell specific TRAF2 and TRAF2 knockout mice) to their controls (n=3 per group).
Project description:We performed RNA-sequencing on hPSCs treated with mitosis poison nocodazol (NOC) or MCL1 inhibitor A1210477 (A121). Our data revealed that NOC and A121 treatment lead to significant upregulation of apoptosis related genes as well as NIK/NF kappa B pathway gene. To investigate effects of anti-apoptotic mutations on hPSCs under stress, we also preformed RNA-seq on BCL-XL overexpression cells and NOXA-/- cells with NOC or A121 treatment. Results showed that anti-apoptotic mutations can promote hPSCs survival by inhibiting both apoptosis pathway and NIK/NF kappa B pathway. Furthermore, SNP analysis showed that cells with anti-apoptotic mutation gained more SNP under NOC or A121 treatment.
Project description:This study sought to evaluate the diffferential gene expression following the conditional knockout of either the canonical (p65) or non-canonical (NIK) NF-κB signaling pathway in myeloid (LysMCre) or intestinal epithelial (VillinCre) cell deletions in a murine model. Genetic susceptibility to colitis-associated colorectal cancer via the chemical induction of AOM/DSS was evaluated on colonic lesion (LT) and healthy tissue (HT) using microarray to assess implicated genes/pathways downstream of NF-kappaB. Abstract from associated publication: Dysregulation of intestinal epithelial cell proliferation is a critical feature in the development of colorectal cancer. This malignancy is typically driven by loss of stem cell regulation in the crypts. Here, we show that NF-κB-inducing kinase (NIK) attenuates colorectal cancer through the regulation of intestinal epithelial cell regeneration and differentiation mediated by noncanonical NF-κB signaling. We observed increased tumor burden in mice lacking NIK either systemically or specifically in intestinal epithelial cells in a model of inflammation-induced tumorigenesis in the colon. Mechanistic studies using crypts and organoids revealed that loss of NIK results in the accumulation of mature, non-dividing colonic epithelial cells, which are more susceptible to mutations and eventual transformation. These findings are consistent with our observations in human colorectal cancer patients revealing a significant decrease in NIK and noncanonical NF-κB signaling. Our work extends previous findings for NIK in attenuating sepsis and gastrointestinal inflammation and defines a critical role for this kinase in colorectal cancer.
Project description:Metabolic reprograming towards aerobic glycolysis is a pivotal mechanism that shapes immune responses. While deregulated T cell metabolism is associated with autoimmune diseases, metabolic deficiency contributes to T cell exhaustion in tumor microenvironment. Here we describe a posttranslational mechanism of glycolysis regulation mediated by the NF-kB-inducing kinase (NIK). NIK deficiency impairs glycolysis induction, rendering CD8 effector T cells hypofunctional with features of exhaustion in tumor microenvironment. Conversely, ectopic expression of NIK promotes CD8 T cell metabolism and prevents exhaustion, thereby profoundly enhancing antitumor immunity and improving the efficacy of T cell adoptive therapy. Interestingly, although NIK is known as a kinase mediating activation of noncanonical NF-kB, NIK regulates T cell metabolism via an NF-kB-independent mechanism that involves stabilization of hexokinase 2 (HK2), a rate-limiting enzyme of the glycolytic pathway. NIK deficiency causes autophagic degradation of HK2, at least in part due to aberrant ROS accumulation. NIK phosphorylates, and maintains the activity of, glucose-6-phosphate dehydrogenase (G6PD), an enzyme mediating production of the antioxidant NADPH required for preventing ROS accumulation and oxidative stress. We provide genetic evidence that the G6PD-NADPH redox system has a vital role in regulating HK2 stability and metabolism in activated T cells. These findings establish NIK as a pivotal regulator of T cell metabolism and highlight a posttranslational mechanism of metabolic regulation involving the G6PD-NADPH redox system.