{"title":"Hypoxia-inducible factor: role in cell survival in superoxide dismutase overexpressing mice after neonatal hypoxia-ischemia.","authors":"Ga Won Jeon, R Ann Sheldon, Donna M Ferriero","doi":"10.3345/kjp.2019.00850","DOIUrl":null,"url":null,"abstract":"<p><strong>Background: </strong>Sixty percent of infants with severe neonatal hypoxic-ischemic encephalopathy die, while most survivors have permanent disabilities. Treatment for neonatal hypoxic-ischemic encephalopathy is limited to therapeutic hypothermia, but it does not offer complete protection. Here, we investigated whether hypoxia-inducible factor (HIF) promotes cell survival and suggested neuroprotective strategies.</p><p><strong>Purpose: </strong>HIF-1α-deficient mice have increased brain injury after neonatal hypoxia-ischemia (HI), and the role of HIF-2α in HI is not well characterized. Copper-zinc superoxide dismutase (SOD)1 overexpression is not beneficial in neonatal HI. The expression of HIF-1α and HIF-2α was measured in SOD1 overexpressing mice and compared to wild-type littermates to see if alteration in expression explains this lack of benefit.</p><p><strong>Methods: </strong>On postnatal day 9, C57Bl/6 mice were subjected to HI, and protein expression was measured by western blotting in the ipsilateral cortex of wild-type and SOD1 overexpressing mice to quantify HIF-1α and HIF-2α. Spectrin expression was also measured to characterize the mechanism of cell death.</p><p><strong>Results: </strong>HIF-1α protein expression did not significantly change after HI injury in the SOD1-overexpressing or wild-type mouse cortex. However, HIF-2α protein expression increased 30 minutes after HI injury in the wild-type and SOD1-overexpressing mouse cortex and decreased to baseline value at 24 hours after HI injury. Spectrin 145/150 expression did not significantly change after HI injury in the SOD1- overexpressing or wild-type mouse cortex. However, spectrin 120 expression increased in both wild-type and SOD1-overexpressing mouse at 4 hours after HI, which decreased by 24 hours, indicating a greater role of apoptotic cell death.</p><p><strong>Conclusion: </strong>HIF-1α and HIF-2α may promote cell survival in neonatal HI in a cell-specific and regional fashion. Our findings suggest that early HIF-2α upregulation precedes apoptotic cell death and limits necrotic cell death. However, the influence of SOD was not clarified; it remains an intriguing factor in neonatal HI.</p>","PeriodicalId":17863,"journal":{"name":"Korean Journal of Pediatrics","volume":"62 12","pages":"444-449"},"PeriodicalIF":0.0000,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ftp.ncbi.nlm.nih.gov/pub/pmc/oa_pdf/54/fa/kjp-2019-00850.PMC6933302.pdf","citationCount":"7","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Korean Journal of Pediatrics","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.3345/kjp.2019.00850","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2019/10/18 0:00:00","PubModel":"Epub","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 7
Abstract
Background: Sixty percent of infants with severe neonatal hypoxic-ischemic encephalopathy die, while most survivors have permanent disabilities. Treatment for neonatal hypoxic-ischemic encephalopathy is limited to therapeutic hypothermia, but it does not offer complete protection. Here, we investigated whether hypoxia-inducible factor (HIF) promotes cell survival and suggested neuroprotective strategies.
Purpose: HIF-1α-deficient mice have increased brain injury after neonatal hypoxia-ischemia (HI), and the role of HIF-2α in HI is not well characterized. Copper-zinc superoxide dismutase (SOD)1 overexpression is not beneficial in neonatal HI. The expression of HIF-1α and HIF-2α was measured in SOD1 overexpressing mice and compared to wild-type littermates to see if alteration in expression explains this lack of benefit.
Methods: On postnatal day 9, C57Bl/6 mice were subjected to HI, and protein expression was measured by western blotting in the ipsilateral cortex of wild-type and SOD1 overexpressing mice to quantify HIF-1α and HIF-2α. Spectrin expression was also measured to characterize the mechanism of cell death.
Results: HIF-1α protein expression did not significantly change after HI injury in the SOD1-overexpressing or wild-type mouse cortex. However, HIF-2α protein expression increased 30 minutes after HI injury in the wild-type and SOD1-overexpressing mouse cortex and decreased to baseline value at 24 hours after HI injury. Spectrin 145/150 expression did not significantly change after HI injury in the SOD1- overexpressing or wild-type mouse cortex. However, spectrin 120 expression increased in both wild-type and SOD1-overexpressing mouse at 4 hours after HI, which decreased by 24 hours, indicating a greater role of apoptotic cell death.
Conclusion: HIF-1α and HIF-2α may promote cell survival in neonatal HI in a cell-specific and regional fashion. Our findings suggest that early HIF-2α upregulation precedes apoptotic cell death and limits necrotic cell death. However, the influence of SOD was not clarified; it remains an intriguing factor in neonatal HI.
期刊介绍:
Korean J Pediatr covers clinical and research works relevant to all aspects of child healthcare. The journal aims to serve pediatricians through the prompt publication of significant advances in any field of pediatrics and to rapidly disseminate recently updated knowledge to the public. Additionally, it will initiate dynamic, international, academic discussions concerning the major topics related to pediatrics. Manuscripts are categorized as review articles, original articles, and case reports. Areas of specific interest include: Growth and development, Neonatology, Pediatric neurology, Pediatric nephrology, Pediatric endocrinology, Pediatric cardiology, Pediatric allergy, Pediatric pulmonology, Pediatric infectious diseases, Pediatric immunology, Pediatric hemato-oncology, Pediatric gastroenterology, Nutrition, Human genetics, Metabolic diseases, Adolescence medicine, General pediatrics.