Mitochondrial inorganic polyphosphate in the mammalian stress response.

摘要 线粒体功能障碍，包括生物能量学失调，已被广泛描述细胞应激下 条件，如在许多人类疾病中发现的条件。然而，驱动线粒体的确切机制 在这些条件下的功能障碍和失败仍然知之甚少，不能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，即使它在线粒体内显示出优选的位置。是 在整个进化过程中非常保守，它存在于每一个被研究的生物体中。聚P的键是 与ATP中发现的那些能量相等，我们和其他人已经证明polyP是一种关键的能量代谢物， （这一建议的科学前提）。此外，polyP在维持细胞内稳态中发挥的关键作用， 某些生物体如细菌和酵母中应激条件是已知的。这也是息肉的情况 参与调节一些关键的线粒体过程，这些过程i）与生物能量密切相关， 哺乳动物细胞的状态，和ii）参与应激反应。这些程序包括： 线粒体钙稳态和线粒体通透性转换孔的形成和开放。 尽管如此，在哺乳动物细胞中，更具体地说，在线粒体中，聚磷酸酶的作用的确切程度仍然是未知的。 生理学;以及这些影响的分子机制仍然是未知的。这种分子 其机制可能涉及肌醇多激酶（IPMK）/AMPK活化蛋白激酶（AMPK）的调节 轴，这将把聚P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polyP在线粒体生理学和细胞生物能量学中的机制作用， 和疾病相关的压力条件。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polyP是细胞生物能量学的关键调节因子， 线粒体生理学在疾病相关的急性应激条件下。聚P对线粒体膜电位的影响 生理学也通过IPMK/AMPK轴的调节发挥作用。为了验证这一假设，我们将使用哺乳动物 细胞模型，其中线粒体polyP的水平将被修改，以及生物化学，细胞 生物学、分子生物学和组学技术。我们将首先优化方法以测定哺乳动物polyP（这是 这是本提案创新的关键组成部分）。随后，我们将研究 polyP对细胞生物能量学和线粒体生理学的影响，以及polyP在生物能量学信号传导中的作用，通过 IPMK/AMPK轴的调节。本申请符合PI和实验室在线粒体 polyP和生物能量学，加速其研究进展。此外，这也符合联合国的长期目标。 PI在这项应用中，这是为了解开驱动线粒体功能障碍和失败的机制，在人类 疾病获得的数据不仅将增加我们对线粒体生理学的了解，还将帮助我们 提出聚P作为一种新的和有前途的潜在药理学工具，用于各种病理条件，其中 已经描述了生物能量学的失调（显著性）。

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).