{"title":"Mitochondrial Calcium Uniporter (MCU) is Involved in an Ischemic Postconditioning Effect Against Ischemic Reperfusion Brain Injury in Mice","authors":"Hiromitsu Sasaki, Ichiro Nakagawa, Takanori Furuta, Shohei Yokoyama, Yudai Morisaki, Yasuhiko Saito, Hiroyuki Nakase","doi":"10.1007/s10571-024-01464-7","DOIUrl":null,"url":null,"abstract":"<p>The phenomenon of ischemic postconditioning (PostC) is known to be neuroprotective against ischemic reperfusion (I/R) injury. One of the key processes in PostC is the opening of the mitochondrial ATP-dependent potassium (mito-K<sub>ATP</sub>) channel and depolarization of the mitochondrial membrane, triggering the release of calcium ions from mitochondria through low-conductance opening of the mitochondrial permeability transition pore. Mitochondrial calcium uniporter (MCU) is known as a highly sensitive transporter for the uptake of Ca<sup>2+</sup> present on the inner mitochondrial membrane. The MCU has attracted attention as a new target for treatment in diseases, such as neurodegenerative diseases, cancer, and ischemic stroke. We considered that the MCU may be involved in PostC and trigger its mechanisms. This research used the whole-cell patch-clamp technique on hippocampal CA1 pyramidal cells from C57BL mice and measured changes in spontaneous excitatory post-synaptic currents (sEPSCs), intracellular Ca<sup>2+</sup> concentration, mitochondrial membrane potential, and <i>N</i>-methyl-<span>d</span>-aspartate receptor (NMDAR) currents under inhibition of MCU by ruthenium red 265 (Ru265) in PostC. Inhibition of MCU increased the occurrence of sEPSCs (<i>p</i> = 0.014), NMDAR currents (<i>p</i> < 0.001), intracellular Ca<sup>2+</sup> concentration (<i>p</i> < 0.001), and dead cells (<i>p</i> < 0.001) significantly after reperfusion, reflecting removal of the neuroprotective effects in PostC. Moreover, mitochondrial depolarization in PostC with Ru265 was weakened, compared to PostC (<i>p</i> = 0.004). These results suggest that MCU affects mitochondrial depolarization in PostC to suppress NMDAR over-activation and prevent elevation of intracellular Ca<sup>2+</sup> concentrations against I/R injury.</p><h3 data-test=\"abstract-sub-heading\">Graphical Abstract</h3>\n","PeriodicalId":9742,"journal":{"name":"Cellular and Molecular Neurobiology","volume":null,"pages":null},"PeriodicalIF":3.6000,"publicationDate":"2024-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Cellular and Molecular Neurobiology","FirstCategoryId":"3","ListUrlMain":"https://doi.org/10.1007/s10571-024-01464-7","RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"CELL BIOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
The phenomenon of ischemic postconditioning (PostC) is known to be neuroprotective against ischemic reperfusion (I/R) injury. One of the key processes in PostC is the opening of the mitochondrial ATP-dependent potassium (mito-KATP) channel and depolarization of the mitochondrial membrane, triggering the release of calcium ions from mitochondria through low-conductance opening of the mitochondrial permeability transition pore. Mitochondrial calcium uniporter (MCU) is known as a highly sensitive transporter for the uptake of Ca2+ present on the inner mitochondrial membrane. The MCU has attracted attention as a new target for treatment in diseases, such as neurodegenerative diseases, cancer, and ischemic stroke. We considered that the MCU may be involved in PostC and trigger its mechanisms. This research used the whole-cell patch-clamp technique on hippocampal CA1 pyramidal cells from C57BL mice and measured changes in spontaneous excitatory post-synaptic currents (sEPSCs), intracellular Ca2+ concentration, mitochondrial membrane potential, and N-methyl-d-aspartate receptor (NMDAR) currents under inhibition of MCU by ruthenium red 265 (Ru265) in PostC. Inhibition of MCU increased the occurrence of sEPSCs (p = 0.014), NMDAR currents (p < 0.001), intracellular Ca2+ concentration (p < 0.001), and dead cells (p < 0.001) significantly after reperfusion, reflecting removal of the neuroprotective effects in PostC. Moreover, mitochondrial depolarization in PostC with Ru265 was weakened, compared to PostC (p = 0.004). These results suggest that MCU affects mitochondrial depolarization in PostC to suppress NMDAR over-activation and prevent elevation of intracellular Ca2+ concentrations against I/R injury.
期刊介绍:
Cellular and Molecular Neurobiology publishes original research concerned with the analysis of neuronal and brain function at the cellular and subcellular levels. The journal offers timely, peer-reviewed articles that describe anatomic, genetic, physiologic, pharmacologic, and biochemical approaches to the study of neuronal function and the analysis of elementary mechanisms. Studies are presented on isolated mammalian tissues and intact animals, with investigations aimed at the molecular mechanisms or neuronal responses at the level of single cells. Cellular and Molecular Neurobiology also presents studies of the effects of neurons on other organ systems, such as analysis of the electrical or biochemical response to neurotransmitters or neurohormones on smooth muscle or gland cells.