Mavroudakis Leonidas, Lanekoff Ingela
Department of Chemistry-BMC, Uppsala University, 75237 Uppsala, Sweden.
Metabolites. 2023 Feb 14;13(2):278. doi: 10.3390/metabo13020278.
Gaining a deep understanding of the molecular mechanisms underlying ischemic stroke is necessary to develop treatment alternatives. Ischemic stroke is known to cause a cellular energy imbalance when glucose supply is deprived, enhancing the role for energy production via β-oxidation where acylcarnitines are essential for the transportation of fatty acids into the mitochondria. Although traditional bulk analysis methods enable sensitive detection of acylcarnitines, they do not provide information on their abundances in various tissue regions. However, with quantitative mass spectrometry imaging the detected concentrations and spatial distributions of endogenous molecules can be readily obtained in an unbiased way. Here, we use pneumatically assisted nanospray desorption electrospray ionization mass spectrometry imaging (PA nano-DESI MSI) doped with internal standards to study the distributions of acylcarnitines in mouse brain affected by stroke. The internal standards enable quantitative imaging and annotation of endogenous acylcarnitines is achieved by studying fragmentation patterns. We report a significant accumulation of long-chain acylcarnitines due to ischemia in brain tissue of the middle cerebral artery occlusion (MCAO) stroke model. Further, we estimate activities of carnitine transporting enzymes and demonstrate disruptions in the carnitine shuttle system that affects the β-oxidation in the mitochondria. Our results show the importance for quantitative monitoring of metabolite distributions in distinct tissue regions to understand cell compensation mechanisms involved in handling damage caused by stroke.
深入了解缺血性中风的分子机制对于开发替代治疗方法至关重要。已知缺血性中风在葡萄糖供应被剥夺时会导致细胞能量失衡，增强通过β-氧化产生能量的作用，其中酰基肉碱对于脂肪酸进入线粒体的运输至关重要。尽管传统的大量分析方法能够灵敏地检测酰基肉碱，但它们无法提供其在各个组织区域中的丰度信息。然而，通过定量质谱成像，可以以无偏倚的方式轻松获得内源性分子的检测浓度和空间分布。在这里，我们使用掺杂内标物的气动辅助纳米喷雾解吸电喷雾电离质谱成像（PA纳米DESI MSI）来研究中风影响的小鼠大脑中酰基肉碱的分布。内标物实现了定量成像，通过研究碎片模式对内源性酰基肉碱进行注释。我们报告在大脑中动脉闭塞（MCAO）中风模型的脑组织中，由于缺血导致长链酰基肉碱显著积累。此外，我们估计了肉碱转运酶的活性，并证明肉碱穿梭系统受到破坏，这影响了线粒体中的β-氧化。我们的结果表明，定量监测不同组织区域中代谢物分布对于理解参与处理中风所致损伤的细胞补偿机制非常重要。
