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Covell DJ, Robinson JL, Akhtar RS, Grossman M, Weintraub D, Bucklin HM, Pitkin RM, Riddle D, Yousef A, Trojanowski JQ, Lee VMY. Novel conformation-selective alpha-synuclein antibodies raised against different in vitro fibril forms show distinct patterns of Lewy pathology in Parkinson's disease. Neuropathol Appl Neurobiol 2017; 43:604-620. [PMID: 28386933 DOI: 10.1111/nan.12402] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Revised: 03/30/2017] [Accepted: 04/07/2017] [Indexed: 12/12/2022]
Abstract
AIMS The aim of this study was to test the hypothesis that different conformations of misfolded α-synuclein (α-syn) are present in Parkinson's disease (PD) brain. METHODS Using two previously characterized conformations of α-syn fibrils, we generated new conformation-selective α-syn monoclonal antibodies (mAbs). We then interrogated multiple brain regions in a well-characterized autopsy cohort of PD patients (n = 49) with these mAbs, Syn7015 and Syn9029. RESULTS Syn7015 detects Lewy bodies (LBs) and Lewy neurites (LNs) formed by pathological α-syn in all brain regions tested, and is particularly sensitive to LNs and small Lewy dots, inclusions believed to form early in the disease. Further, we observed colocalization between Syn7015 and an early marker of α-syn pathology formation, phospho-Ser129-α-syn, and a lack of extensive colocalization with markers of more mature pathology. In comparison, Syn9029 detects Lewy pathology in all regions examined, but indicates significantly fewer LNs than Syn7015. In addition, colocalization of Syn9029 with later markers of α-syn pathology maturation (ubiquitin and P62) suggests that the pathology detected by Syn9029 is older. Semiquantitative scoring of both LN and LB pathology in nine brain regions further established this trend, with Syn7015 LN scores consistently higher than Syn9029 LN scores. CONCLUSIONS Our data indicate that different conformations of α-syn pathology are present in PD brain and correspond to different stages of maturity for Lewy pathology. Regional analysis of Syn7015 and Syn9029 immunostaining also provides support for the Braak hypothesis that α-syn pathology advances through the brain.
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Affiliation(s)
- D J Covell
- Center for Neurodegenerative Disease Research and Institute on Aging, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - J L Robinson
- Center for Neurodegenerative Disease Research and Institute on Aging, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - R S Akhtar
- Center for Neurodegenerative Disease Research and Institute on Aging, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA.,Department of Neurology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - M Grossman
- Department of Neurology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - D Weintraub
- Departments of Psychiatry and Neurology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - H M Bucklin
- Center for Neurodegenerative Disease Research and Institute on Aging, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - R M Pitkin
- Center for Neurodegenerative Disease Research and Institute on Aging, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - D Riddle
- Center for Neurodegenerative Disease Research and Institute on Aging, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - A Yousef
- Center for Neurodegenerative Disease Research and Institute on Aging, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - J Q Trojanowski
- Center for Neurodegenerative Disease Research and Institute on Aging, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - V M-Y Lee
- Center for Neurodegenerative Disease Research and Institute on Aging, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
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Abstract
Neural precursor cells (NPCs) are markedly sensitive to apoptotic insults. p53-Dependent transcriptional activation of proapoptotic genes has been hypothesized to regulate NPC death in response to DNA damage. Recent studies of non-NPCs have also indicated that p53 may directly interact with Bcl-2 molecules and thereby regulate death independently of transcription. The contribution of transcription-independent p53 activation in NPC death has not been characterized. In this study, we found that apoptosis caused by chemotherapeutic agents in NPCs required p53 expression and new macromolecular synthesis. In contrast, NPC death induced by staurosporine, a broad kinase inhibitor, is regulated by p53 in the absence of macromolecular synthesis. The apoptosis effector molecules Bax and Bak, Apaf-1, and caspase-9 were shown to be downstream of p53 in both pathways. These findings indicate that p53 is in a unique position to regulate at least two distinct signaling portals that activate the intrinsic apoptotic death pathway in NPCs.
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Affiliation(s)
- R S Akhtar
- Department of Pathology, Division of Neuropathology, University of Alabama at Birmingham, SC 961, 1530 3rd Avenue South, Birmingham, AL 35294-0017, USA
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