Evidence for Decreased Nucleolar PARP-1 as an Early Marker of Cognitive Impairment

Poly(ADP-ribose) polymerase-1 (PARP-1) is a nuclear protein that regulates gene expression through poly(ADP)-ribosylation, resulting in the loosening of chromatin structure. PARP-1 enzymatic activity has been shown to be necessary for the expression of several genes required for memory formation and...

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Main Authors: Matthew Regier, Jiancong Liang, Alexander Choi, Kavita Verma, Jenny Libien, A. Iván Hernández
Format: Article
Language:English
Published: Wiley 2019-01-01
Series:Neural Plasticity
Online Access:http://dx.doi.org/10.1155/2019/4383258
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author Matthew Regier
Jiancong Liang
Alexander Choi
Kavita Verma
Jenny Libien
A. Iván Hernández
author_facet Matthew Regier
Jiancong Liang
Alexander Choi
Kavita Verma
Jenny Libien
A. Iván Hernández
author_sort Matthew Regier
collection DOAJ
description Poly(ADP-ribose) polymerase-1 (PARP-1) is a nuclear protein that regulates gene expression through poly(ADP)-ribosylation, resulting in the loosening of chromatin structure. PARP-1 enzymatic activity has been shown to be necessary for the expression of several genes required for memory formation and consolidation. Previously, we showed that nucleolar PARP-1 is significantly decreased in hippocampal pyramidal cells in Alzheimer’s disease (AD). We proposed that the displacement of PARP-1 from the nucleolus results in downregulation of new rRNA expression and ribosome biogenesis, leading to cognitive impairment. To further investigate the relationship between nucleolar PARP-1 and memory impairment, we examined PARP-1 expression in the hippocampi of individuals with mild cognitive impairment (MCI) compared to control and AD cases. We used immunohistochemical techniques to examine the nucleolar distribution of PARP-1 in the Cornu Ammonis (CA region) of the hippocampus. PARP-1 positive cells were then scored for the presence or absence of PARP-1 in the nucleolus. We found a significant decrease of PARP-1 staining in the nucleolar compartment of hippocampal pyramidal cells in MCI compared with Control and AD. When the four CA (CA1-4) regions were considered separately, only the CA1 region showed significant differences in nucleolar PARP-1 with Control > AD > MCI cases. Categorization of nucleolar PARP-1 into “distinct” and “diffuse” groups suggest that most of the changes occur within the distinct group. In addition, measurements of the nucleolar diameter of nucleolar PARP-1 positive cells in CA2 and CA4 showed Control > MCI. Thus, MCI cases had a lower percentage of PARP-1 nucleolar positive cells in CA1 and smaller nucleolar diameters in CA2 and CA4, compared to Control. Our data suggest that disruption of nucleolar form and function is an early and important step in the progression of cognitive impairment.
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spelling doaj-art-b5bd09356721474885c66e643cb7beaa2025-02-03T06:11:22ZengWileyNeural Plasticity2090-59041687-54432019-01-01201910.1155/2019/43832584383258Evidence for Decreased Nucleolar PARP-1 as an Early Marker of Cognitive ImpairmentMatthew Regier0Jiancong Liang1Alexander Choi2Kavita Verma3Jenny Libien4A. Iván Hernández5Department of Pathology, Downstate Medical Center, State University of New York, Brooklyn, NY, USADepartment of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, USADepartment of Neurology, Downstate Medical Center, State University of New York, Brooklyn, NY, USADepartment of Pathology, Downstate Medical Center, State University of New York, Brooklyn, NY, USADepartment of Pathology, Downstate Medical Center, State University of New York, Brooklyn, NY, USADepartment of Pathology, Downstate Medical Center, State University of New York, Brooklyn, NY, USAPoly(ADP-ribose) polymerase-1 (PARP-1) is a nuclear protein that regulates gene expression through poly(ADP)-ribosylation, resulting in the loosening of chromatin structure. PARP-1 enzymatic activity has been shown to be necessary for the expression of several genes required for memory formation and consolidation. Previously, we showed that nucleolar PARP-1 is significantly decreased in hippocampal pyramidal cells in Alzheimer’s disease (AD). We proposed that the displacement of PARP-1 from the nucleolus results in downregulation of new rRNA expression and ribosome biogenesis, leading to cognitive impairment. To further investigate the relationship between nucleolar PARP-1 and memory impairment, we examined PARP-1 expression in the hippocampi of individuals with mild cognitive impairment (MCI) compared to control and AD cases. We used immunohistochemical techniques to examine the nucleolar distribution of PARP-1 in the Cornu Ammonis (CA region) of the hippocampus. PARP-1 positive cells were then scored for the presence or absence of PARP-1 in the nucleolus. We found a significant decrease of PARP-1 staining in the nucleolar compartment of hippocampal pyramidal cells in MCI compared with Control and AD. When the four CA (CA1-4) regions were considered separately, only the CA1 region showed significant differences in nucleolar PARP-1 with Control > AD > MCI cases. Categorization of nucleolar PARP-1 into “distinct” and “diffuse” groups suggest that most of the changes occur within the distinct group. In addition, measurements of the nucleolar diameter of nucleolar PARP-1 positive cells in CA2 and CA4 showed Control > MCI. Thus, MCI cases had a lower percentage of PARP-1 nucleolar positive cells in CA1 and smaller nucleolar diameters in CA2 and CA4, compared to Control. Our data suggest that disruption of nucleolar form and function is an early and important step in the progression of cognitive impairment.http://dx.doi.org/10.1155/2019/4383258
spellingShingle Matthew Regier
Jiancong Liang
Alexander Choi
Kavita Verma
Jenny Libien
A. Iván Hernández
Evidence for Decreased Nucleolar PARP-1 as an Early Marker of Cognitive Impairment
Neural Plasticity
title Evidence for Decreased Nucleolar PARP-1 as an Early Marker of Cognitive Impairment
title_full Evidence for Decreased Nucleolar PARP-1 as an Early Marker of Cognitive Impairment
title_fullStr Evidence for Decreased Nucleolar PARP-1 as an Early Marker of Cognitive Impairment
title_full_unstemmed Evidence for Decreased Nucleolar PARP-1 as an Early Marker of Cognitive Impairment
title_short Evidence for Decreased Nucleolar PARP-1 as an Early Marker of Cognitive Impairment
title_sort evidence for decreased nucleolar parp 1 as an early marker of cognitive impairment
url http://dx.doi.org/10.1155/2019/4383258
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