Neuronal Pnn Deficiency Increases Oxidative Stress and Exacerbates Cerebral Ischemia/Reperfusion Injury in Mice

Shu-Yuan Hsu; Chih-Hung Chen; Sujira Mukda; Steve Leu

doi:10.3390/antiox11030466

Neuronal Pnn Deficiency Increases Oxidative Stress and Exacerbates Cerebral Ischemia/Reperfusion Injury in Mice

Antioxidants (Basel). 2022 Feb 26;11(3):466. doi: 10.3390/antiox11030466.

Authors

Shu-Yuan Hsu^{1

2}, Chih-Hung Chen³, Sujira Mukda⁴, Steve Leu^{2

5}

Affiliations

¹ Department of Anatomy, Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan.
² Institute for Translational Research in Biomedicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung 833401, Taiwan.
³ Department of Internal Medicine, Divisions of General Medicine, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung 833401, Taiwan.
⁴ Research Center for Neuroscience, Institute of Molecular Biosciences, Mahidol University, Salaya, Nakornpathom 73170, Thailand.
⁵ Department of Biotechnology, College of Life Science, Kaohsiung Medical University, Kaohsiung 807378, Taiwan.

Abstract

Cerebral stroke remains one of the leading causes of death worldwide. Ischemic stroke caused by the sudden loss of blood flow in brain is the major type of cerebral stroke. In addition to necrotic cell death in the ischemic core region, neuronal apoptosis is usually observed in the ischemic penumbra. Pnn, a multi-functional protein, participates in cellular proliferation, migration, differentiation, apoptosis as well as cell-cell interaction through its abilities in regulating gene transcription and mRNA processing. Our recent studies have demonstrated that Pnn has a cell type-specific distribution manner in neural cells under ischemic injury and plays a protective role in astrocytes against ischemic stress. In this study, we generated an inducible neuron-specific Pnn deficiency mouse model to further investigate the physiological role of Pnn in neurons. To directly examine the role of neuronal Pnn in ischemic stress, four weeks after induction of Pnn deficiency in neurons, middle cerebral artery occlusion (MCAO) was applied to induce cerebral ischemia/reperfusion in mice. In the cerebrum and hippocampus with neuronal Pnn depletion, the expression of SRSF2, a mRNA splicing regulator, was increased, while the expression of SRSF1, a functional antagonist of SRSF2, was reduced. Expression levels of ROS generators (NOX-1 and NOX-2) and antioxidant proteins (GR, HO-1, NQO-1) were upregulated in brain tissue with loss of neuronal Pnn, echoing an increase in oxidized proteins in cortical and hippocampal neurons. Furthermore, the expression of DNA damage marker, p53bp1, was found in the choroid plexus of mice with neuronal Pnn depletion. In mice with MCAO, compared to wild type mice, both increased cerebral infarcted area and elevated expressions of proapoptotic proteins were found in mice with neuronal Pnn depletion. In conclusion, Pnn deficiency increases oxidative stress in neurons and exacerbates cerebral ischemia/reperfusion injury in mice.

Keywords: Pnn; ischemia/reperfusion; mRNA alternative splicing; neuron; oxidative stress.

Abstract

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