Mitochondrial inorganic polyphosphate in the mammalian stress response.

摘要 线粒体功能障碍，包括生物能量失调，已在细胞应激下被广泛描述 条件，例如许多人类疾病中发现的条件。然而，驱动线粒体的确切机制 对这些条件下的功能障碍和失败的了解仍然太少，无法实现有效的治疗靶向。 无机多磷酸盐 (polyP) 是一种普遍存在的分子，即使它显示出线粒体内的首选位置。它是 在整个进化过程中都极其保守，并且存在于每个研究的生物体中。 PolyP 的键为 与 ATP 中的物质等能量，我们和其他人已经证明，polyP 是一种关键的能量代谢物 （该提议的科学前提）。此外，polyP 在维持细胞稳态方面发挥着关键作用。 某些生物体（例如细菌和酵母）的应激条件是已知的。 PolyP 的情况也是如此 参与一些关键线粒体过程的调节，这些过程 i) 与生物能密切相关 哺乳动物细胞的状态，以及 ii) 参与应激反应。这些过程包括，监管 线粒体钙稳态和线粒体通透性过渡孔的形成和开放。 尽管如此，polyP 在哺乳动物细胞，更具体地说，线粒体中的影响的确切程度 生理学；以及这些效应背后的分子机制仍然大多未知。这个分子 机制可能涉及肌醇多激酶 (IPMK)/AMPK 激活蛋白激酶 (AMPK) 的调节 轴，它将把polyP作为哺乳动物生物能量学中的信号分子。该项目的目标是 阐明线粒体多聚蛋白在线粒体生理学和细胞生物能学中的机制作用，在基础条件下 以及与疾病相关的应激条件。为了实现这一目标，根据参考书目和我们的初步数据， 我们的总体假设是：哺乳动物线粒体多聚蛋白是细胞生物能量的关键调节因子，并且 疾病相关急性应激条件下的线粒体生理学。 PolyP对线粒体的影响 生理学也通过 IPMK/AMPK 轴的调节来发挥作用。为了验证这个假设，我们将使用哺乳动物 细胞模型中线粒体多聚蛋白的水平将被改变，并且结合生化、细胞 生物学、分子生物学和组学技术。我们将首先优化检测哺乳动物多聚蛋白的方法（这是 该提案创新的重要组成部分）。随后，我们将研究合理的监管效应 PolyP 对细胞生物能学和线粒体生理学的影响，以及 PolyP 在生物能学信号传导中的作用，通过 IPMK/AMPK 轴的调节。该应用程序符合 PI 和实验室在线粒体方面的专业知识 PolyP 和生物能量学，加速了他们的研究进展。而且，这也符合我们的长远目标。 该应用的 PI，旨在揭示人类线粒体功能障碍和衰竭的机制 疾病。获得的数据不仅会增加我们对线粒体生理学的了解，还将帮助我们 提出polyP作为一种新的、有前途的潜在药理学工具，用于治疗各种病理状况，其中 生物能量失调已被描述（意义）。

ABSTRACT Mitochondrial dysfunction, including bioenergetics dysregulation, has been broadly described under cellular stress conditions, such as those found in many human diseases. However, the exact mechanisms that drive mitochondria to dysfunction and failure under these conditions are still too poorly understood to enable effective therapeutic targeting. Inorganic polyphosphate (polyP) is a ubiquitous molecule, even if it shows a preferred location within mitochondria. It is extremely well-conserved throughout evolution, and it is present in every studied organism. The bonds of polyP are isoenergetic to those found in ATP, and we and others have already demonstrated that polyP is a key energy metabolite (scientific premise for this proposal). Moroever, the key role played by polyP in maintaining cellular homeostasis under stress conditions in some organisms, such as bacteria and yeast, is already known. This is also the case for polyP’s involvement in the regulation of some crucial mitochondrial processes which are i) closely related to the bioenergetic status of mammalian cells, and ii) involved in the stress response. These processes include, the regulation of mitochondrial calcium homeostasis and the formation and opening of the mitochondrial permeability transition pore. Nonetheless, the exact extent of the effects of polyP in mammalian cellular, and more specifically, mitochondrial physiology; as well as the molecular mechanism underlying these effects still remain mostly unknown. This molecular mechanism could involve the regulation of the inositol multikinase (IPMK)/AMPK-Activated protein kinase (AMPK) axis, which will place polyP as a signaling molecule in mammalian bioenergetics. The objective of this project is to elucidate the mechanistic role of mitochondrial polyP in mitochondrial physiology and cellular bioenergetics, under basal and disease-relevant stress conditions. To accomplish this objective, based on the bibliography and our preliminary data, our global hypothesis is that: mammalian mitochondrial polyP is a key regulator of cellular bioenergetics and mitochondrial physiology under disease-relevant acute stress conditions. The effects of polyP on mitochondrial physiology are also exerted via the regulation of the IPMK/AMPK axis. To test this hypothesis, we will use mammalian cellular models in which the levels of mitochondrial polyP will be modified, and a combination of biochemical, cell biology, molecular biology, and -omics techniques. We will first optimize the methods to assay mammalian polyP (this is a crucial component of the innovation of this proposal). Subsequently, we will study the plausible regulatory effects of polyP on cellular bioenergetics and mitochondrial physiology, as well as polyP’s role in bioenergetics signaling, via the regulation of the IPMK/AMPK axis. This application aligns with the PI’s and laboratory’s expertise in mitochondrial polyP and bioenergetics, accelerating the progress of their research. Moreover, it is in line with the long-term goal of the PI on this application, which is to unravel the mechanisms that drive mitochondrial to dysfunction and failure in human disease. The obtained data will not only increase our knowledge of mitochondrial physiology, it will also help us to propose polyP as a new and promising potential pharmacological tool for various pathological conditions where the dysregulation of bioenergetics has been described (significance).