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Moderately Inducing Autophagy Reduces Tertiary Brain Injury after Perinatal Hypoxia-Ischemia

Recent studies of cerebral hypoxia-ischemia (HI) have highlighted slowly progressive neurodegeneration whose mechanisms remain elusive, but if blocked, could considerably improve long-term neurological function. We previously established that the cytokine transforming growth factor (TGF)β1 is highly...

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Autores principales: Kim, Brian H., Jeziorek, Maciej, Kanal, Hur Dolunay, Contu, Viorica Raluca, Dobrowolski, Radek, Levison, Steven W.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8070811/
https://www.ncbi.nlm.nih.gov/pubmed/33919804
http://dx.doi.org/10.3390/cells10040898
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author Kim, Brian H.
Jeziorek, Maciej
Kanal, Hur Dolunay
Contu, Viorica Raluca
Dobrowolski, Radek
Levison, Steven W.
author_facet Kim, Brian H.
Jeziorek, Maciej
Kanal, Hur Dolunay
Contu, Viorica Raluca
Dobrowolski, Radek
Levison, Steven W.
author_sort Kim, Brian H.
collection PubMed
description Recent studies of cerebral hypoxia-ischemia (HI) have highlighted slowly progressive neurodegeneration whose mechanisms remain elusive, but if blocked, could considerably improve long-term neurological function. We previously established that the cytokine transforming growth factor (TGF)β1 is highly elevated following HI and that delivering an antagonist for TGFβ receptor activin-like kinase 5 (ALK5)—SB505124—three days after injury in a rat model of moderate pre-term HI significantly preserved the structural integrity of the thalamus and hippocampus as well as neurological functions associated with those brain structures. To elucidate the mechanism whereby ALK5 inhibition reduces cell death, we assessed levels of autophagy markers in neurons and found that SB505124 increased numbers of autophagosomes and levels of lipidated light chain 3 (LC3), a key protein known to mediate autophagy. However, those studies did not determine whether (1) SB was acting directly on the CNS and (2) whether directly inducing autophagy could decrease cell death and improve outcome. Here we show that administering an ALK5 antagonist three days after HI reduced actively apoptotic cells by ~90% when assessed one week after injury. Ex vivo studies using the lysosomal inhibitor chloroquine confirmed that SB505124 enhanced autophagy flux in the injured hemisphere, with a significant accumulation of the autophagic proteins LC3 and p62 in SB505124 + chloroquine treated brain slices. We independently activated autophagy using the stimulatory peptide Tat-Beclin1 to determine if enhanced autophagy is directly responsible for improved outcomes. Administering Tat-Beclin1 starting three days after injury preserved the structural integrity of the hippocampus and thalamus with improved sensorimotor function. These data support the conclusion that intervening at this phase of injury represents a window of opportunity where stimulating autophagy is beneficial.
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spelling pubmed-80708112021-04-26 Moderately Inducing Autophagy Reduces Tertiary Brain Injury after Perinatal Hypoxia-Ischemia Kim, Brian H. Jeziorek, Maciej Kanal, Hur Dolunay Contu, Viorica Raluca Dobrowolski, Radek Levison, Steven W. Cells Article Recent studies of cerebral hypoxia-ischemia (HI) have highlighted slowly progressive neurodegeneration whose mechanisms remain elusive, but if blocked, could considerably improve long-term neurological function. We previously established that the cytokine transforming growth factor (TGF)β1 is highly elevated following HI and that delivering an antagonist for TGFβ receptor activin-like kinase 5 (ALK5)—SB505124—three days after injury in a rat model of moderate pre-term HI significantly preserved the structural integrity of the thalamus and hippocampus as well as neurological functions associated with those brain structures. To elucidate the mechanism whereby ALK5 inhibition reduces cell death, we assessed levels of autophagy markers in neurons and found that SB505124 increased numbers of autophagosomes and levels of lipidated light chain 3 (LC3), a key protein known to mediate autophagy. However, those studies did not determine whether (1) SB was acting directly on the CNS and (2) whether directly inducing autophagy could decrease cell death and improve outcome. Here we show that administering an ALK5 antagonist three days after HI reduced actively apoptotic cells by ~90% when assessed one week after injury. Ex vivo studies using the lysosomal inhibitor chloroquine confirmed that SB505124 enhanced autophagy flux in the injured hemisphere, with a significant accumulation of the autophagic proteins LC3 and p62 in SB505124 + chloroquine treated brain slices. We independently activated autophagy using the stimulatory peptide Tat-Beclin1 to determine if enhanced autophagy is directly responsible for improved outcomes. Administering Tat-Beclin1 starting three days after injury preserved the structural integrity of the hippocampus and thalamus with improved sensorimotor function. These data support the conclusion that intervening at this phase of injury represents a window of opportunity where stimulating autophagy is beneficial. MDPI 2021-04-14 /pmc/articles/PMC8070811/ /pubmed/33919804 http://dx.doi.org/10.3390/cells10040898 Text en © 2021 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Kim, Brian H.
Jeziorek, Maciej
Kanal, Hur Dolunay
Contu, Viorica Raluca
Dobrowolski, Radek
Levison, Steven W.
Moderately Inducing Autophagy Reduces Tertiary Brain Injury after Perinatal Hypoxia-Ischemia
title Moderately Inducing Autophagy Reduces Tertiary Brain Injury after Perinatal Hypoxia-Ischemia
title_full Moderately Inducing Autophagy Reduces Tertiary Brain Injury after Perinatal Hypoxia-Ischemia
title_fullStr Moderately Inducing Autophagy Reduces Tertiary Brain Injury after Perinatal Hypoxia-Ischemia
title_full_unstemmed Moderately Inducing Autophagy Reduces Tertiary Brain Injury after Perinatal Hypoxia-Ischemia
title_short Moderately Inducing Autophagy Reduces Tertiary Brain Injury after Perinatal Hypoxia-Ischemia
title_sort moderately inducing autophagy reduces tertiary brain injury after perinatal hypoxia-ischemia
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8070811/
https://www.ncbi.nlm.nih.gov/pubmed/33919804
http://dx.doi.org/10.3390/cells10040898
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