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

在衰老过程中，控制细胞对损伤的促凋亡刺激的存活对于维持细胞和组织的健康是必不可少的，过量的促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)暴露在广泛的外在促凋亡刺激下，这些刺激已被证明导致软骨细胞数量减少，最终导致骨关节炎。因此，了解软骨细胞存活的关键调控途径(作为一种模型细胞类型)是至关重要的，以响应更多的促凋亡刺激以实现健康衰老。重要的是，我们已经确认Ucn1(Ucn1)是软骨细胞中一个有效的促生存因子，并有初步证据表明Ucn1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Ucn1-Ca~(2+)信号是控制细胞在暴露于外在促凋亡刺激(如NO水平升高或过度机械应激)后存活的重要轴。因此，使用软骨细胞作为一个模型系统，其中外部促凋亡刺激负责导致与年龄相关的细胞数量下降，我们现在试图研究这种拮抗剂诱导细胞死亡的分子基础以及Ucn1介导的对NO和过度机械负荷的保护。为了研究这些假设，学生将首先通过使用si-RNA筛选板来鉴定在该系统中起作用的非选择性阳离子通道。他们将利用原始的人体细胞刺激(例如NO)，以及药理抑制研究和一系列最先进的分析技术。此外，复杂的软骨负荷参数将被模拟并应用于评估损伤性负荷对猪和人骨关节炎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.