Defining a role for non-canonical mTORC1 activity at focal adhesions

雷帕霉素是一种最初从复活节岛上收集的细菌中分离出来的药物，也被称为拉帕努伊岛。它特异性抑制雷帕霉素复合体1的机制靶点（mTORC1），这是一种进化上保守的蛋白质复合体，整合有丝分裂和应激信号来控制细胞生长和代谢。自从四十年前雷帕霉素被发现以来，由于其免疫抑制和抗肿瘤的特性而被广泛使用。然而最近，它作为一种很有前景的抗衰老药物而受到关注。在酵母、苍蝇、鱼和老鼠等实验室“动物”模型中进行的研究表明，雷帕霉素治疗与热量限制具有相似的效果，而热量限制是促进健康寿命和寿命的最有力干预措施之一。然而，人类雷帕霉素治疗与许多鲜为人知的副作用有关，包括伤口愈合受损。这些副作用限制了使用雷帕霉素支持健康人类衰老的可行性。在这项研究中，我们想要探索我们已经确定的特定mTORC1库的作用和调控。我们最近的论文首次描述了mTORC1可以在细胞边缘被激活，靠近与局灶黏附相关的蛋白质（Rabanal-Ruiz et al, 2021）。这些是专门的结构，负责将细胞锚定在细胞外环境。这些结构的动态性质在细胞迁移过程中是重要的，这是伤口愈合的最早阶段之一，将伤口关闭到外部环境。我们的初步和已发表的数据表明，mTORC1活性和局灶黏附之间存在紧密的相互调节；即，局灶黏附的破坏会损害mTORC1的激活，而相反，抑制mTORC1会导致局灶黏附数量、大小和定位的变化。此外，我们的工作表明，这个特定的mTORC1池不受传统调节器的控制，因此我们想要确定它是如何控制的。鉴于雷帕霉素对伤口愈合的不利影响，我们提出局灶粘连附近的mTORC1库在这一过程中起着重要而特殊的作用。因此，这项资助的目的是确定在局灶粘连中控制mTORC1的机制，并确定其在细胞迁移和伤口愈合中的生理作用。这些数据可能为未来发展治疗方案提供信息，以减轻雷帕霉素的副作用，使其成为健康老龄化干预措施的广泛使用。

Rapamycin is a drug that was originally isolated from bacteria collected on Easter Island, also known as Rapa Nui. It specifically inhibits the mechanistic Target Of Rapamycin Complex 1 (mTORC1), an evolutionarily conserved protein complex that integrates mitogenic and stress signals to control cell growth and metabolism. Since its discovery forty years ago, rapamycin has been used extensively for its immunosuppressive and antitumour properties. More recently however, it has gained attention as a promising anti-ageing drug. Work in laboratory 'animal' models, such as yeast, flies, fish and mice has shown that treatment with rapamycin has similar effects to caloric restriction which is one of the most robust interventions to promote healthspan and lifespan. Rapamycin treatment in humans is however associated with a number of poorly understood side effects, including impaired wound healing. Such side-effects limit the feasibility of using rapamycin to support healthy human ageing. In this study, we want to explore the role and regulation of a specific pool of mTORC1 that we have identified. Our recent manuscript described, for the first time, that mTORC1 can be activated at the cell edge, in close proximity to proteins associated with focal adhesions (Rabanal-Ruiz et al, 2021). These are specialist structures responsible for anchoring cells to the extracellular environment. The dynamic nature of these structures is important during cell migration, one of the earliest stages of wound healing to close the wound off to the outside environment. Our preliminary and published data indicates that there is tight reciprocal regulation of mTORC1 activity and focal adhesions; namely, disruption of focal adhesions impairs mTORC1 activation while conversely, inhibition of mTORC1 leads to changes in focal adhesion number, size and localisation. Furthermore, our work indicates that this specific pool of mTORC1 is not controlled via classical regulators, and thus we want to identify exactly how it is controlled. Given the detrimental impact of rapamycin on wound healing, we propose that the pool of mTORC1 in the vicinity of focal adhesions plays an important and specific role in this process. The aim of this grant is to therefore identify the mechanisms controlling mTORC1 at focal adhesions and determine its physiological role in cell migration and wound healing. These data may inform on the future development of therapeutic options to mitigate the side-effects of rapamycin, allowing its widespread use a healthy ageing intervention.