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Posiphen Reduces the Levels of Huntingtin Protein through Translation Suppression

Posiphen tartrate (Posiphen) is an orally available small molecule that targets a conserved regulatory element in the mRNAs of amyloid precursor protein (APP) and α-synuclein (αSYN) and inhibits their translation. APP and αSYN can cause neurodegeneration when their aggregates induce neurotoxicity. T...

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Autores principales: Chen, Xu-Qiao, Barrero, Carlos A., Vasquez-Del Carpio, Rodrigo, Reddy, E. Premkumar, Fecchio, Chiara, Merali, Salim, Deglincerti, Alessia, Fang, Cheng, Rogers, Jack, Maccecchini, Maria L.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8708689/
https://www.ncbi.nlm.nih.gov/pubmed/34959389
http://dx.doi.org/10.3390/pharmaceutics13122109
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author Chen, Xu-Qiao
Barrero, Carlos A.
Vasquez-Del Carpio, Rodrigo
Reddy, E. Premkumar
Fecchio, Chiara
Merali, Salim
Deglincerti, Alessia
Fang, Cheng
Rogers, Jack
Maccecchini, Maria L.
author_facet Chen, Xu-Qiao
Barrero, Carlos A.
Vasquez-Del Carpio, Rodrigo
Reddy, E. Premkumar
Fecchio, Chiara
Merali, Salim
Deglincerti, Alessia
Fang, Cheng
Rogers, Jack
Maccecchini, Maria L.
author_sort Chen, Xu-Qiao
collection PubMed
description Posiphen tartrate (Posiphen) is an orally available small molecule that targets a conserved regulatory element in the mRNAs of amyloid precursor protein (APP) and α-synuclein (αSYN) and inhibits their translation. APP and αSYN can cause neurodegeneration when their aggregates induce neurotoxicity. Therefore, Posiphen is a promising drug candidate for neurodegenerative diseases, including Alzheimer’s disease and Parkinson’s disease. Posiphen’s safety has been demonstrated in three independent phase I clinical trials. Moreover, in a proof of concept study, Posiphen lowered neurotoxic proteins and inflammatory markers in cerebrospinal fluid of mild cognitive impaired patients. Herein we investigated whether Posiphen reduced the expression of other proteins, as assessed by stable isotope labeling with amino acids in cell culture (SILAC) followed by mass spectrometry (MS)-based proteomics. Neuroblastoma SH-SY5Y cells, an in vitro model of neuronal function, were used for the SILAC protein profiling response. Proteins whose expression was altered by Posiphen treatment were characterized for biological functions, pathways and networks analysis. The most significantly affected pathway was the Huntington’s disease signaling pathway, which, along with huntingtin (HTT) protein, was down-regulated by Posiphen in the SH-SY5Y cells. The downregulation of HTT protein by Posiphen was confirmed by quantitative Western blotting and immunofluorescence. Unchanged mRNA levels of HTT and a comparable decay rate of HTT proteins after Posiphen treatment supported the coclusion that Posiphen reduced HTT via downregulation of the translation of HTT mRNA. Meanwhile, the downregulation of APP and αSYN proteins by Posiphen was also confirmed. The mRNAs encoding HTT, APP and αSYN contain an atypical iron response element (IRE) in their 5′-untranslated regions (5′-UTRs) that bind iron regulatory protein 1 (IRP1), and Posiphen specifically bound this complex. Conversely, Posiphen did not bind the IRP1/IRE complex of mRNAs with canonical IREs, and the translation of these mRNAs was not affected by Posiphen. Taken together, Posiphen shows high affinity binding to the IRE/IRP1 complex of mRNAs with an atypical IRE stem loop, inducing their translation suppression, including the mRNAs of neurotoxic proteins APP, αSYN and HTT.
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spelling pubmed-87086892021-12-25 Posiphen Reduces the Levels of Huntingtin Protein through Translation Suppression Chen, Xu-Qiao Barrero, Carlos A. Vasquez-Del Carpio, Rodrigo Reddy, E. Premkumar Fecchio, Chiara Merali, Salim Deglincerti, Alessia Fang, Cheng Rogers, Jack Maccecchini, Maria L. Pharmaceutics Communication Posiphen tartrate (Posiphen) is an orally available small molecule that targets a conserved regulatory element in the mRNAs of amyloid precursor protein (APP) and α-synuclein (αSYN) and inhibits their translation. APP and αSYN can cause neurodegeneration when their aggregates induce neurotoxicity. Therefore, Posiphen is a promising drug candidate for neurodegenerative diseases, including Alzheimer’s disease and Parkinson’s disease. Posiphen’s safety has been demonstrated in three independent phase I clinical trials. Moreover, in a proof of concept study, Posiphen lowered neurotoxic proteins and inflammatory markers in cerebrospinal fluid of mild cognitive impaired patients. Herein we investigated whether Posiphen reduced the expression of other proteins, as assessed by stable isotope labeling with amino acids in cell culture (SILAC) followed by mass spectrometry (MS)-based proteomics. Neuroblastoma SH-SY5Y cells, an in vitro model of neuronal function, were used for the SILAC protein profiling response. Proteins whose expression was altered by Posiphen treatment were characterized for biological functions, pathways and networks analysis. The most significantly affected pathway was the Huntington’s disease signaling pathway, which, along with huntingtin (HTT) protein, was down-regulated by Posiphen in the SH-SY5Y cells. The downregulation of HTT protein by Posiphen was confirmed by quantitative Western blotting and immunofluorescence. Unchanged mRNA levels of HTT and a comparable decay rate of HTT proteins after Posiphen treatment supported the coclusion that Posiphen reduced HTT via downregulation of the translation of HTT mRNA. Meanwhile, the downregulation of APP and αSYN proteins by Posiphen was also confirmed. The mRNAs encoding HTT, APP and αSYN contain an atypical iron response element (IRE) in their 5′-untranslated regions (5′-UTRs) that bind iron regulatory protein 1 (IRP1), and Posiphen specifically bound this complex. Conversely, Posiphen did not bind the IRP1/IRE complex of mRNAs with canonical IREs, and the translation of these mRNAs was not affected by Posiphen. Taken together, Posiphen shows high affinity binding to the IRE/IRP1 complex of mRNAs with an atypical IRE stem loop, inducing their translation suppression, including the mRNAs of neurotoxic proteins APP, αSYN and HTT. MDPI 2021-12-07 /pmc/articles/PMC8708689/ /pubmed/34959389 http://dx.doi.org/10.3390/pharmaceutics13122109 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 Communication
Chen, Xu-Qiao
Barrero, Carlos A.
Vasquez-Del Carpio, Rodrigo
Reddy, E. Premkumar
Fecchio, Chiara
Merali, Salim
Deglincerti, Alessia
Fang, Cheng
Rogers, Jack
Maccecchini, Maria L.
Posiphen Reduces the Levels of Huntingtin Protein through Translation Suppression
title Posiphen Reduces the Levels of Huntingtin Protein through Translation Suppression
title_full Posiphen Reduces the Levels of Huntingtin Protein through Translation Suppression
title_fullStr Posiphen Reduces the Levels of Huntingtin Protein through Translation Suppression
title_full_unstemmed Posiphen Reduces the Levels of Huntingtin Protein through Translation Suppression
title_short Posiphen Reduces the Levels of Huntingtin Protein through Translation Suppression
title_sort posiphen reduces the levels of huntingtin protein through translation suppression
topic Communication
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8708689/
https://www.ncbi.nlm.nih.gov/pubmed/34959389
http://dx.doi.org/10.3390/pharmaceutics13122109
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