BAFF as a novel SASP factor and regulator of senescent traits

正在进行的工作 目的1.BAFF在衰老过程中的调节作用。 我们证实细胞因子BAFF(Steri M等人，2017)在多种衰老模型中升高。由于BAFF在髓系细胞中的高表达，我们将重点放在THP-1(人单核细胞)细胞中的BAFF的产生上，以进行分子分析。我们发现BAFF在衰老的THP-1细胞中被转录诱导，并增加了BAFF前体mRNA的水平。我们使用ECRbase(https://ecrbase.dcode.org))寻找可能驱动BAFF转录的转录因子，发现BAFF启动子含有几个与干扰素调节因子转录因子家族成员的结合位点(Sjstrand M等人，2016年)。此外，IRF1沉默显著降低了IR诱导的衰老过程中BAFF Pre-mRNA和BAFF蛋白的水平，表明BAFF在衰老细胞中作为I型干扰素反应的一部分受到IRF1的转录调控。 目的2.研究包括SASP在内的BAFF在衰老过程中的信号转导途径。 为了分析BAFF对衰老的影响，我们在THP-1细胞中沉默了BAFF，然后实施了IR诱导的衰老。我们观察到，BAFF沉默降低了SA-BetaGal的活性。有趣的是，沉默的BAFF降低了SASP因子，包括促炎细胞因子IL-8、IL-6、IL-1/和肿瘤坏死因子以及抗炎细胞因子IL-10。这些发现促使我们分析了炎症反应的主要调节因子--核因子-B途径。我们观察到，BAFF沉默降低了p50和p52的水平，分别代表典型和非典型的NF-B途径。相应地，编码细胞因子和趋化因子的几个转录本的水平也降低了。这些发现表明，BAFF可能作为SASP的上游调节因子，至少部分通过NF-B途径发挥作用。 未来计划 深入分析BAFF在衰老中的作用。 在衰老过程中使用belimumab中和BAFF(Blair等人，2018年)并评估SASP水平。 格式塔样本中人血清循环BAFF随年龄变化的定量研究。

ONGOING WORK AIM 1. BAFF regulation in senescence. We confirmed that the cytokine BAFF (Steri M et al., 2017) is elevated in multiple models of senescence. Due to its high expression in myeloid cell lines, we focused on BAFF production in THP-1 (human monocytic) cells for molecular analysis. We found that BAFF is transcriptionally induced in senescent THP-1 cells with enhanced levels of BAFF pre-mRNA. We used ECRbase (https://ecrbase.dcode.org) to identify transcription factors potentially driving BAFF transcription and found that BAFF promoter harbors several binding sites for members of the Interferon Regulated Factor (IRF) transcription factor family (Sjstrand M et al., 2016). Moreover, IRF1 silencing strongly reduced BAFF pre-mRNA and BAFF protein levels in IR-induced senescence, suggesting that BAFF is transcriptionally regulated by IRF1 in senescent cells as a part of the Interferon Type I response. AIM 2. To study BAFF signaling pathways in senescence including SASP. In order to analyze the impact of BAFF on senescence, we silenced BAFF in THP-1 cells and then implemented IR-induced senescence. We observed that BAFF silencing decreased SA-betaGal activity. Interestingly, silencing BAFF decreased SASP factors including the pro-inflammatory cytokines IL-8, IL-6, IL-1/, and TNF and the anti-inflammatory cytokine IL-10. These findings prompted us to analyze NF-B pathway, a major regulator of the inflammatory responses. We observed that BAFF silencing decreased the levels of p50 and p52, representing the canonical and non-canonical NF-B pathways, respectively. Accordingly, the level of several transcripts encoding cytokines and chemokines also decreased. These findings suggest that BAFF may act as an upstream regulator of the SASP, at least in part by acting through the NF-B pathway. FUTURE PLANS In-depth analysis of BAFF functions in senescence. Neutralization of BAFF using Belimumab (Blair et al, 2018) in senescence and evaluation of SASP levels. Quantification of circulating BAFF in human serum as a function of age in GESTALT samples.