Irp2基因缺陷小鼠的脑铁代谢异常与轻度神经和行为障碍有关。

Abnormal brain iron metabolism in Irp2 deficient mice is associated with mild neurological and behavioral impairments.

作者信息

Zumbrennen-Bullough Kimberly B, Becker Lore, Garrett Lillian, Hölter Sabine M, Calzada-Wack Julia, Mossbrugger Ilona, Quintanilla-Fend Leticia, Racz Ildiko, Rathkolb Birgit, Klopstock Thomas, Wurst Wolfgang, Zimmer Andreas, Wolf Eckhard, Fuchs Helmut, Gailus-Durner Valerie, de Angelis Martin Hrabě, Romney Steven J, Leibold Elizabeth A

机构信息

Program in Anemia Signaling Research, Division of Nephrology, Program in Membrane Biology, Center for Systems Biology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, United States of America.

German Mouse Clinic, Helmholtz-Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany; Institute of Experimental Genetics, Helmholtz-Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany.

出版信息

PLoS One. 2014 Jun 4;9(6):e98072. doi: 10.1371/journal.pone.0098072. eCollection 2014.

Abstract

Iron Regulatory Protein 2 (Irp2, Ireb2) is a central regulator of cellular iron homeostasis in vertebrates. Two global knockout mouse models have been generated to explore the role of Irp2 in regulating iron metabolism. While both mouse models show that loss of Irp2 results in microcytic anemia and altered body iron distribution, discrepant results have drawn into question the role of Irp2 in regulating brain iron metabolism. One model shows that aged Irp2 deficient mice develop adult-onset progressive neurodegeneration that is associated with axonal degeneration and loss of Purkinje cells in the central nervous system. These mice show iron deposition in white matter tracts and oligodendrocyte soma throughout the brain. A contrasting model of global Irp2 deficiency shows no overt or pathological signs of neurodegeneration or brain iron accumulation, and display only mild motor coordination and balance deficits when challenged by specific tests. Explanations for conflicting findings in the severity of the clinical phenotype, brain iron accumulation and neuronal degeneration remain unclear. Here, we describe an additional mouse model of global Irp2 deficiency. Our aged Irp2-/- mice show marked iron deposition in white matter and in oligodendrocytes while iron content is significantly reduced in neurons. Ferritin and transferrin receptor 1 (TfR1, Tfrc), expression are increased and decreased, respectively, in the brain from Irp2-/- mice. These mice show impairments in locomotion, exploration, motor coordination/balance and nociception when assessed by neurological and behavioral tests, but lack overt signs of neurodegenerative disease. Ultrastructural studies of specific brain regions show no evidence of neurodegeneration. Our data suggest that Irp2 deficiency dysregulates brain iron metabolism causing cellular dysfunction that ultimately leads to mild neurological, behavioral and nociceptive impairments.

摘要

铁调节蛋白2(Irp2,Ireb2)是脊椎动物细胞铁稳态的核心调节因子。已构建了两种全身性敲除小鼠模型来探究Irp2在调节铁代谢中的作用。虽然这两种小鼠模型均显示Irp2缺失会导致小细胞性贫血和机体铁分布改变,但相互矛盾的结果使Irp2在调节脑铁代谢中的作用受到质疑。一种模型显示,老年Irp2缺陷小鼠会发生成年期起病的进行性神经退行性变,这与轴突变性和中枢神经系统中浦肯野细胞的丧失有关。这些小鼠在整个大脑的白质束和少突胶质细胞胞体中出现铁沉积。另一种全身性Irp2缺陷的对比模型未显示神经退行性变或脑铁蓄积的明显或病理迹象,仅在接受特定测试时表现出轻度的运动协调和平衡缺陷。关于临床表型严重程度、脑铁蓄积和神经元变性方面相互矛盾的研究结果的解释仍不清楚。在此,我们描述了另一种全身性Irp2缺陷的小鼠模型。我们的老年Irp2 - / - 小鼠在白质和少突胶质细胞中显示出明显的铁沉积,而神经元中的铁含量显著降低。Irp2 - / - 小鼠大脑中的铁蛋白和转铁蛋白受体1(TfR1,Tfrc)表达分别增加和减少。通过神经学和行为测试评估时,这些小鼠在运动、探索、运动协调/平衡和痛觉感受方面存在障碍,但缺乏神经退行性疾病的明显迹象。对特定脑区的超微结构研究未发现神经退行性变的证据。我们的数据表明,Irp2缺陷会导致脑铁代谢失调,引起细胞功能障碍,最终导致轻度的神经、行为和痛觉感受损伤。

https://cdn.ncbi.nlm.nih.gov/pmc/blobs/b66a/4045679/9776f6c35fed/pone.0098072.g001.jpg

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