Project description:Senescent cells release a variety of cytokines, proteases and growth factors collectively defined as the Senescent Secretory Associated Phenotype (SASP). Sustained SASP induces a pattern of chronic inflammation associated with aging and implicated in multiple age-related diseases. Here, we investigated the expression and function of the immunomodulatory cytokine BAFF (B-cell activating factor), a SASP factor, in multiple senescence models. First, we characterized BAFF production across different senescence models, including senescent human diploid fibroblasts (WI-38, IMR-90) and monocytic leukemia cells (THP-1), and tissues of mice induced to undergo senescence. We identified IRF1 (interferon response factor 1) as a transcription factor required for promoting BAFF mRNA transcription in senescence, and found that suppressing BAFF production decreased the senescent phenotype in both monocytes and fibroblasts. Importantly, the influence of BAFF on the senescence program was cell type-specific: in monocytes, BAFF promoted the early activation of NF-κB and general SASP secretion, while in fibroblasts, BAFF contributed to the production and function of TP53 (p53). Overall, BAFF silencing affected shared senescence-associated phenotypes including IL6 secretion, SA-beta-Gal staining, and γ-H2AX accumulation. We propose that BAFF is a novel biomarker of senescence and a potential target for senotherapy.
Project description:Emerging clinical evidence points to a function for B cell activating factor (BAFF) in pregnancy. However, a direct role for BAFF-axis members including BAFF, the closely related a proliferation-inducing ligand (APRIL), and their respective receptors in pregnancy has not been examined. This study demonstrates that loss of BAFF results in decreased inflammatory responsiveness and decreased susceptibility to inflammation-induced preterm birth (PTB). In contrast, loss of APRIL increases inflammatory responsiveness and susceptibility to PTB. Consistent with overlapping receptor utilization by BAFF and APRIL, deletion of BAFF-axis receptors is not sufficient to modify susceptibility to PTB. Critically, therapeutic administration of BAFF/APRIL monoclonal antibodies or recombinant proteins is sufficient to manipulate susceptibility to inflammation-induced PTB. Further, macrophages are identified as the principle BAFF producing immune cells at the maternal-fetal interface and BAFF and APRIL divergently manipulate macrophage gene expression and inflammatory function. Genes linked to labor initiation are upregulated in WT and APRIL deficient macrophages while downregulated in BAFF deficient macrophages and correlate with myeloid gene expression in human placental samples during labor. Thus, BAFF and APRIL play important, but divergent, counterregulatory inflammatory roles in pregnancy and provide new therapeutic targets for mitigating the risk of PTB.
Project description:Emerging evidence indicates BAFF to be an important cytokine influencing anti-tumoral immunity. We generated a BAFF-overexpressing B16.F10 (BAFF) melanoma cell model and found that a significant survival advantage was conferred to C57BL/6 mice inoculated with BAFF cells. BAFF tumors had decreased myeloid infiltrates with lower PD-L1 expression. Monocyte depletion and anti-PD-L1 antibody treatment confirmed the functional significance on the phenotype. RNA-Seq analysis confirmed that monocytes isolated from BAFF tumors where characterized by a decreased exhaustive phenotype and enriched for in genes activating adaptive immune responses and NF- signaling. We wondered about the clinical relevance of BAFF plasma levels in melanoma patients. Evaluation of late stage metastatic melanoma patients treated with inhibitors of the PD-1/PD-L1 axis demonstrated a stratification of patients with high and low BAFF plasma levels, the former of which experienced lower responses to anti-PD-1 immunotherapies. In summary, we have shown that BAFF, through effects on tumor infiltrating monocytes not only impacts primary tumor growth but as biomarker can contribute to predicting response to anti-PD1 immunotherapy in later stages of advanced disease.
Project description:Tumor necrosis factor-associated factors 2 and 3 (TRAF2 and TRAF3) were shown to function in a co-operative and non-redundant manner to suppress nuclear factor-κB2 (NF-κB2) activation, gene expression and survival in mature B cells. In the absence of this suppressive activity, B cells developed independently of the obligatory B cell survival factor, BAFF (B cell activating factor of the tumor necrosis factor family). This constitutive, lineage-specific suppression of B cell survival by TRAF2 and TRAF3 determines the requirement for BAFF to sustain B cell development in vivo. We wished to investigate the effect on gene expression in B cells which lacked the negative regulators TRAF2 and TRAF3, and hence had hyperactive NF-kB2 signalling. As Baff-tg mice display a similar phenotype, and have a genetic modification which acts in the same pathway, yet further up, than TRAF2 and TRAF3, we wished to compare and contrast Baff-tg B cells with TRAF2 and TRAF3 deficient B cells. This analysis should identify genes that are important in B cell survival. Experiment Overall Design: Lymph node B cells were purified from Traf2 B cell knockout mice, Traf3 B cell knockout mice, Baff-tg mice and respective controls. RNA was extracted and hybridised to Affymetrix 430 2.0 Mouse Genome Arrays. Samples were processed and hence analysed on three spearate days. Day 1 two control mice: Traf2lox/lox pool and CD19-cretg were compared to two knockout mice: Traf2DB 80 and Traf3DB 94. On Day 2 three control mice: Traf2lox/lox 77, Traf2lox/lox 79 and Traf3lox/lox 97 were compared to two knockout mice: Traf2DB 76 and Traf3DB 01. On Day 3 three control mice: WT33, WT34, WT35 were compared to three Baff-tg mice: Baff-tg 99, Baff-tg 100, Baff-tg 101.
Project description:The purpose of the study was to identify downstream gene targets regulated by a new alternative splice of BAFF (B-Cell Activating factor belonging to the TNF Family) that we called Delta4-BAFF (because it characterized by an alternative splice of exon 4). To do this we used human burkitt's lymphoma cell line (RAMOS) stably transfected with Delta4-BAFF or stably transfected with Delta4-BAFF mutated on its N-glycosylation site (Delta4-BAFF-N124D). One control was used : RAMOS stably transfected with empty vector (pIRES2-GFP from Clontech)
Project description:RNAseq analysis of BAFF in vitro-stimulated (6 hours) murine nfkb2fl/flCD19-Cre (furtheron designated as REL) and CD19-Cre (furtheron designated as WT) splenic B cells identifies genes regulated by the transcription factor NF-kB2 in BAFF-stimulated B cells.
Project description:Tumor necrosis factor-associated factors 2 and 3 (TRAF2 and TRAF3) were shown to function in a co-operative and non-redundant manner to suppress nuclear factor-κB2 (NF-κB2) activation, gene expression and survival in mature B cells. In the absence of this suppressive activity, B cells developed independently of the obligatory B cell survival factor, BAFF (B cell activating factor of the tumor necrosis factor family). This constitutive, lineage-specific suppression of B cell survival by TRAF2 and TRAF3 determines the requirement for BAFF to sustain B cell development in vivo. We wished to investigate the effect on gene expression in B cells which lacked the negative regulators TRAF2 and TRAF3, and hence had hyperactive NF-kB2 signalling. As Baff-tg mice display a similar phenotype, and have a genetic modification which acts in the same pathway, yet further up, than TRAF2 and TRAF3, we wished to compare and contrast Baff-tg B cells with TRAF2 and TRAF3 deficient B cells. This analysis should identify genes that are important in B cell survival. Keywords: Genetic modification
Project description:In this project, we profiled the proteome of 46 diverse CLL samples with data-independent acquisition mass spectrometry (DIA-MS), in order to undertand the protein-level pathway changes that are related to CLL proliferative drive (CLL-PD)
Project description:Chronic lymphocytic leukemia (CLL) is a disease with a highly variable prognosis. The clinical course can however be predicted thanks to prognostic markers. Poor prognosis is associated with expression of a B cell receptor (BCR) from unmutated immunoglobulin variable heavy-chain genes (IgVH) and expression of zeta associated protein of 70 kDa (ZAP-70). The reason why ZAP-70 expression is associated with poor prognosis and whether the protein has a direct pathogenic function is at present unknown. By transfer of ZAP-70 to CLL cells, we show here that expression of ZAP-70 in CLL cells leads to increased expression of the NF-κB target genes interleukin-1β (IL-1β), IL-6 and IL-8 upon BCR triggering. This could be blocked by inhibition of NF-κB signaling through inhibition of IκB kinases (IKK). Transcriptome analysis identified a NF-κB RelA signature imposed by ZAP-70 expression in BCR stimulated CLL cells. We conclude that ZAP-70 acts directly as an amplifier of NF-κB signaling in CLL cells which could be an underlying mechanism for its association with poor prognosis and which may represent a therapeutic target.
Project description:The aim of the study was to illucidate how BAFF mediates B cell survival and growth through the identification of BAFF-regulated genes. Keywords: cell stimulation