Roles for altered Wnt signaling and oxidative stress response pathways as primary drivers of reduced reparative capacity in aging canine lung mesenchymal stromal cells

项目摘要 一种新的范式假设，细胞衰老是由表观遗传学改变驱动的 发育信号通路。另一种理论表明，对 氧化应激反应、DNA损伤积累、全球表观遗传漂移或代谢 副产品积累更重要。我们无法确定 细胞衰老突显了我们在设计有效的治疗和逆转方法方面的一个关键差距 与年龄相关的疾病病理学。人类的衰老与组织修复减少有关， 肺功能下降，对慢性肺部疾病的易感性增加 这是进步的、破坏性的和不可逆转的。我们在这项拟议工作中的总体目标是 确定高增殖性多能性患者年龄相关功能下降的主要驱动因素 肺间充质基质细胞(LMSCs)。像其他组织驻留的MSCs一样，LMSCs紧密地 受调节的，在发育和成人组织修复中至关重要，对年龄相关的敏感 监管失调。我们之前已经证明，衰老的小鼠会减少肺修复 容量和减少的LMSC功能。我们提议的工作将确定LMSC老化的驱动因素 伴犬，一种新的自然衰老模型，在这种模型中，我们可以识别广泛保守的 与人类衰老有关的机制。我们的中心假设是表观遗传调控 Wnt信号通路和氧化应激反应通路的变化主要是相互依存的 衰老LMSCs修复功能减退的驱动因素。这一中心假设是基于我们的 初步数据显示，从老年犬分离的aLMSCs克隆形成能力较低， 细胞增殖、Wnt信号成分表达谱改变与氧化反应 基因，与yLMSCs相比，改变了对氧化应激的适应性反应(从 幼犬)。我们将通过追求以下两个具体目标来检验我们的中心假设。 目标1.确定Wnt信号的调节如何导致与年龄相关的修复能力下降 LMSCs的能力。从我们的初步数据来看，我们的工作假设是表观遗传学 与yLMSCs相比，Wnt信号的改变降低了aLMSCs的修复能力。目标2. 确定老年LMSCs细胞对氧化应激反应的调节驱动因素。从我们的 初步数据，我们的工作假设是关键适应性氧化的表观遗传变化 应激反应基因导致氧化反应失调和修复能力降低 ALMSCs与yLMSCs的容量。我们的理由是，我们将确定保守的驱动因素 骨髓间充质干细胞的增龄性功能下降对了解其发病机制至关重要 人类患者中的年龄相关疾病。

Project Summary An emerging paradigm postulates that cellular aging is driven by epigenetic alterations of developmental signaling pathways. Alternative theories suggest that dysregulation of the oxidative stress response, DNA damage accumulation, global epigenetic drift, or metabolic byproduct accumulation are more important. Our inability to identify the primary drivers of cellular aging highlights a critical gap in our ability to design effective ways to treat and reverse age-related disease pathologies. Aging in humans is associated with reduced tissue repair, declining pulmonary function, and an enhanced susceptibility to chronic pulmonary diseases that are progressive, destructive and irreversible. Our overall objective in this proposed work is to identify the primary drivers of age-related functional decline in highly proliferative multipotent lung mesenchymal stromal cells (LMSCs). Like other tissue resident MSCs, LMSCs are tightly regulated, critical in development and adult tissue repair, and sensitive to age-related dysregulation. We have previously demonstrated that aging mice have reduced lung repair capacity and reduced LMSC function. Our proposed work will identify drivers of LMSC aging in companion dogs, a novel naturally-aging model in which we can identify broadly conserved mechanisms relevant to human aging. Our central hypothesis is that epigenetically-regulated changes in Wnt signaling and oxidative stress response pathways are interdependent primary drivers of reduced reparative function in aging LMSCs. This central hypothesis is based on our preliminary data showing that aLMSCs (isolated from aged dogs) have lower clonogenicity and proliferation, altered expression profiles of Wnt signaling components and oxidative response genes, and altered adaptive response to oxidative stress compared to yLMSCs (isolated from young dogs). We will test our central hypothesis by pursuing the following two specific aims. Aim 1. Identify how regulation of Wnt signaling drives the age-related decrease in reparative capacity of LMSCs. From our preliminary data, our working hypothesis is that epigenetic changes in Wnt signaling drive reduced reparative capacity in aLMSCs versus yLMSCs. Aim 2. Identify regulatory drivers of the cellular response to oxidative stress in aged LMSCs. From our preliminary data, our working hypothesis is that epigenetic changes in key adaptive oxidative stress response genes leads to a dysregulated oxidative response and reduced reparative capacity in aLMSCs versus yLMSCs. Our rationale is that we will identify conserved drivers of age-related functional decline in MSCs that will be critical for understanding the pathogenesis of age-related diseases in human patients.