The pro-survival effect of Urocortin1 on articular chondrocytes through modulation of calcium influx

响应于有害的促细胞凋亡刺激的细胞存活的控制对于在衰老期间维持细胞和组织健康是必不可少的，并且过量的促细胞凋亡刺激可导致细胞死亡和与年龄相关的疾病。在关节软骨中，常驻细胞群（软骨细胞）暴露于广泛的外源性促凋亡刺激，其已显示导致软骨细胞数量减少并最终导致骨关节炎。因此，有必要了解参与软骨细胞存活（作为一种模型细胞类型）的关键调控途径，以响应增加促凋亡刺激，使健康的老龄化。重要的是，我们已经确定了尿皮质素-1（Ucn 1）作为一种有效的促生存因子在软骨细胞中，并有初步证据表明，Ucn 1通过调节非选择性阳离子通道发挥其保护作用。因此，我们假设Ucn 1-Ca 2+信号是一个重要的轴暴露于外源性促凋亡刺激，如NO水平升高，或过度的机械应力后，细胞存活的控制。因此，我们使用软骨细胞作为模型系统，其中外部促凋亡刺激导致细胞数量与年龄相关的下降，我们现在试图研究这种拮抗剂诱导的细胞死亡和Ucn 1介导的NO和过度机械负荷保护的分子基础。为了研究这些假设，学生将首先确定该系统中起作用的非选择性阳离子通道，通过使用si-RNA筛选板。他们将利用原代人类细胞刺激（例如NO），沿着药理学抑制研究和一系列最先进的分析技术。此外，将模拟复杂的软骨载荷参数，并应用于评估损伤载荷对猪和人骨关节炎软骨中软骨细胞健康的影响。

Control of cell survival in response to injurious pro-apoptotic stimuli is essential for maintenance of cell and tissue health during ageing and an excess of pro-apoptotic stimuli can lead to cell death and to age-related disease. In articular cartilage, the resident cell population (chondrocytes) are exposed to a wide range of extrinsic pro-apoptotic stimuli which have been shown to result in a decrease in chondrocyte number and ultimately in osteoarthritis. It is thus essential to understand the key regulatory pathways involved in chondrocyte survival (as a model cell type) in response to increased pro-apoptotic stimuli to enable healthy ageing.Importantly, we have identified urocortin-1 (Ucn1) as a potent pro-survival factor in chondrocytes and have preliminary evidence that Ucn1 exerts its protective effect by modulating a non-selective cation channel. Thus, we hypothesise that Ucn1-Ca2+signalling is an essential axis for control of cell survival following exposure to extrinsic pro-apoptotic stimuli, such as increased NO levels, or excessive mechanical stress. Therefore, using chondrocytes as a model system in which extrinsic pro-apoptotic stimuli are responsible for causing an age-related decline in cell number, we now seek to investigate the molecular basis of this antagonist-induced cell death and Ucn1 mediated protection from NO and excessive mechanical load.To investigate these hypotheses, the student will first work to identify the non-selective cation channel at work in this system, through use of an si-RNA screening plate. They will utilise primary human cell stimulation (e.g. NO), along with pharmacological inhibition studies and a range of state-of-the-art analytical techniques. Additionally, complex cartilage loading parameters will be modelled and applied to assess the effect of injurious load upon chondrocyte health in both porcine and human osteoarthritic cartilage.