Targeting cell senescence in a novel model of spontaneous disc degeneration

椎间盘退变是与慢性颈部和腰痛相关的主要危险因素， 影响全世界数百万人的普遍存在的健康状况。有一个不完整的理解 椎间盘退变的发病机制部分是由于缺乏适当的动物模型。当前动物 模型主要使用创伤性损伤来促进与大多数人类椎间盘病例不同的退化 退化虽然，一些动物模型的自发性椎间盘退变的报道，一些局限性， 防止其广泛使用。因此，非常需要更具代表性的小动物模型 人类椎间盘病理学以前的研究调查了近交系小鼠，包括SM/J和LG/J 因为它们的再生能力。与LG/J相比，SM/J是一个“超级治疗者”菌株，被发现是一个“差的治疗者”。 然而，没有研究调查这些品系小鼠的椎间盘健康状况。我们第一次展示 SM/J小鼠表现出自发性椎间盘退变的时间，其捕获了人类椎间盘的重要特征 病理基于我们新的试点数据，我们假设这种退行性表型具有很强的遗传易感性。 基础和细胞表型，代谢和衰老的早期变化驱动。我们将调查 细胞和遗传机制的基础上的椎间盘退变的SM/J小鼠在三个目的。在目标1中， 检验SM/J小鼠椎间盘退变的特征在于细胞存活受损、改变 细胞表型、代谢和衰老。我们将对NP-RNA的NP组织进行RNA-Seq和ChIP-Seq分析。 SM/J和LG/J小鼠。我们还将进行代谢组学，以确定细胞的代谢状态。这些研究 将为转录组和代谢的时间变化提供公正的见解， SM/J小鼠椎间盘退变发病机制的核心途径和机制。在目标2中， 测试从椎间盘中去除衰老细胞减缓椎间盘疾病进展的假设。 SM/J小鼠的椎间盘退变。初步研究表明，衰老细胞的积累， SM/J盘。我们将在早期和建立期对离体器官培养的椎间盘和SM/J小鼠进行体内治疗， 用特征明确的衰老清除药物对椎间盘退变分期进行分析， 和基因变化。最后，在目标3中，我们将描述有助于细胞增殖的遗传机制。 衰老和椎间盘退变。我们将进行全基因组关联研究（GWAS） 使用LG/J x SM/J高级互交系（AIL）来发现小鼠基因组中有助于 椎间盘退变的差异。为此，将在143，000 GIGAmuga芯片上对AIL小鼠进行基因分型 将来自几只小鼠的单核苷酸多态性（SNP）和圆盘用于RNA-Seq分析。 总之，这些数据将被用来确定高分辨率的数量性状基因座（QTL）的光盘性状~5基因 每个支撑间隔。将鉴定负责这些QTL的基因。这一目标将产生候选人 可能导致LG/J和SM/J品系之间衰老和椎间盘退变变异的基因。

Intervertebral disc degeneration is the major risk factor associated with chronic neck and low back pain, ubiquitous health conditions that affects millions of people world-wide. There is an incomplete understanding of the pathogenesis of disc degeneration partially due to lack of an appropriate animal model. Current animal models primarily use traumatic insults to promote degeneration differing from most human cases of disc degeneration. While, a few animal models of spontaneous disc degeneration are reported, several limitations prevent their wide-spread use. Thus, there is a great need for small animal models that are more representative of human disc pathology. Previous studies have investigated inbred strains of mice including SM/J and LG/J for their regenerative ability. In contrast to LG/J, a “super healer” strain, SM/J was found to be a “poor healer”. However, there no studies have investigated the disc health status in these strains of mice. We show for the first time that SM/J mice exhibit spontaneous disc degeneration that captures important features of human disc pathology. Based on our novel pilot data, we hypothesize that this degenerative phenotype has a strong genetic basis and driven by early changes in cell phenotype, metabolism and senescence. We will investigate the cellular and genetic mechanisms that underlie disc degeneration in SM/J mice in three Aims. In Aim 1 we will test the hypothesis that disc degeneration in SM/J mice is characterized by compromised cell survival, altered cell phenotype, metabolism and senescence. We will perform RNA-Seq and ChIP-Seq analysis of NP tissue of SM/J and LG/J mice. We will also perform metabolomics to determine metabolic status of cells. These studies will provide unbiased insights into temporal alterations in transcriptome and metabolism to delineate pathways and mechanisms central to the pathogenesis of disc degeneration in SM/J mice. In Aim 2 we will test the hypothesis that removal of senescent cells from the intervertebral disc slows down the progression of disc degeneration in SM/J mice. Pilot studies have shown that there is an accumulation of senescent cells in SM/J discs. We will treat ex vivo organ cultured discs and SM/J mice in vivo during early and established stages of disc degeneration with well-characterized senolytic drugs and analyze metabolic, histopathological and genetic changes. Lastly in Aim 3 we will delineate the genetic mechanisms that contribute to cell senescence and disc degeneration in SM/J mice. We will perform a genome-wide association study (GWAS) using LG/J x SM/J Advanced Intercross Lines (AILs) to discover regions of the mouse genome contributing to differences in disc degeneration. For this purpose, AIL mice will be genotyped at 143,000 GIGAmuga chip single nucleotide polymorphisms (SNPs) and discs from several mice will be used for RNA-Seq analysis. Together, these data will be used to identify high-resolution quantitative trait loci (QTL) for disc traits ~5 genes per support interval. The genes responsible for these QTL will be identified. This aim will generate candidate genes likely contributing to variation in the senescence and disc degeneration between LG/J and SM/J strains.