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Clemons GA, Silva ACE, Acosta CH, Udo MSB, Tesic V, Rodgers KM, Wu CYC, Citadin CT, Lee RHC, Neumann JT, Allani S, Prentice H, Zhang Q, Lin HW. Protein arginine methyltransferase 4 modulates nitric oxide synthase uncoupling and cerebral blood flow in Alzheimer's disease. J Cell Physiol 2024; 239:e30858. [PMID: 36036549 PMCID: PMC9971360 DOI: 10.1002/jcp.30858] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 07/17/2022] [Accepted: 08/08/2022] [Indexed: 12/14/2022]
Abstract
Alzheimer's disease (AD) is the leading cause of mortality, disability, and long-term care burden in the United States, with women comprising the majority of AD diagnoses. While AD-related dementia is associated with tau and amyloid beta accumulation, concurrent derangements in cerebral blood flow have been observed alongside these proteinopathies in humans and rodent models. The homeostatic production of nitric oxide synthases (NOS) becomes uncoupled in AD which leads to decreased NO-mediated vasodilation and oxidative stress via the production of peroxynitrite (ONOO-∙) superoxide species. Here, we investigate the role of the novel protein arginine methyltransferase 4 (PRMT4) enzyme function and its downstream product asymmetric dimethyl arginine (ADMA) as it relates to NOS dysregulation and cerebral blood flow in AD. ADMA (type-1 PRMT product) has been shown to bind NOS as a noncanonic ligand causing enzymatic dysfunction. Our results from RT-qPCR and protein analyses suggest that aged (9-12 months) female mice bearing tau- and amyloid beta-producing transgenic mutations (3xTg-AD) express higher levels of PRMT4 in the hippocampus when compared to age- and sex-matched C57BL6/J mice. In addition, we performed studies to quantify the expression and activity of different NOS isoforms. Furthermore, laser speckle contrast imaging analysis was indicative that 3xTg-AD mice have dysfunctional NOS activity, resulting in reduced production of NO metabolites, enhanced production of free-radical ONOO-, and decreased cerebral blood flow. Notably, the aforementioned phenomena can be reversed via pharmacologic PRMT4 inhibition. Together, these findings implicate the potential importance of PRMT4 signaling in the pathogenesis of Alzheimer's-related cerebrovascular derangement.
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Affiliation(s)
- Garrett A Clemons
- Department of Cellular Biology & Anatomy, Louisiana State University Health Sciences Center, Shreveport, Louisiana, USA
| | | | - Christina H Acosta
- Department of Cellular Biology & Anatomy, Louisiana State University Health Sciences Center, Shreveport, Louisiana, USA
| | - Mariana Sayuri Berto Udo
- Department of Neurology, Louisiana State University Health Sciences Center, Shreveport, Louisiana, USA
| | - Vesna Tesic
- Department of Neurology, Louisiana State University Health Sciences Center, Shreveport, Louisiana, USA
| | - Krista M Rodgers
- Department of Cellular Biology & Anatomy, Louisiana State University Health Sciences Center, Shreveport, Louisiana, USA
| | - Celeste Yin-Chieh Wu
- Department of Neurology, Louisiana State University Health Sciences Center, Shreveport, Louisiana, USA
| | - Cristiane T Citadin
- Department of Cellular Biology & Anatomy, Louisiana State University Health Sciences Center, Shreveport, Louisiana, USA
| | - Reggie Hui-Chao Lee
- Department of Neurology, Louisiana State University Health Sciences Center, Shreveport, Louisiana, USA
| | - Jake T Neumann
- Department of Biomedical Sciences, West Virginia School of Osteopathic Medicine, Lewisburg, West Virginia, USA
| | - Shailaja Allani
- Center for Molecular Biology and Biotechnology, Florida Atlantic University, Jupiter, Florida, USA
| | - Howard Prentice
- Department of Biomedical Sciences, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, Florida, USA
| | - Quanguang Zhang
- Department of Neurology, Louisiana State University Health Sciences Center, Shreveport, Louisiana, USA
| | - Hung Wen Lin
- Department of Cellular Biology & Anatomy, Louisiana State University Health Sciences Center, Shreveport, Louisiana, USA
- Department of Neurology, Louisiana State University Health Sciences Center, Shreveport, Louisiana, USA
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Hamey JJ, Rakow S, Bouchard C, Senst JM, Kolb P, Bauer UM, Wilkins MR, Hart-Smith G. Systematic investigation of PRMT6 substrate recognition reveals broad specificity with a preference for an RG motif or basic and bulky residues. FEBS J 2021; 288:5668-5691. [PMID: 33764612 DOI: 10.1111/febs.15837] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 03/17/2021] [Accepted: 03/23/2021] [Indexed: 10/21/2022]
Abstract
Protein arginine methyltransferase 6 (PRMT6) catalyses the asymmetric dimethylation of arginines on numerous substrate proteins within the human cell. In particular, PRMT6 methylates histone H3 arginine 2 (H3R2) which affects both gene repression and activation. However, the substrate specificity of PRMT6 has not been comprehensively analysed. Here, we systematically characterise the substrate recognition motif of PRMT6, finding that it has broad specificity and recognises the RG motif. Working with a H3 tail peptide as a template, on which we made 204 amino acid substitutions, we use targeted mass spectrometry to measure their effect on PRMT6 in vitro activity. We first show that PRMT6 methylates R2 and R8 in the H3 peptide, although H3R8 is methylated with lower efficiency and is not an in vivo PRMT6 substrate. We then quantify the effect of 194 of these amino acid substitutions on methylation at both H3R2 and H3R8. In both cases, we find that PRMT6 tolerates essentially any amino acid substitution in the H3 peptide, but that positively charged and bulky residues are preferred near the target arginine. We show that PRMT6 also has preference for glycine, but only in the position immediately following the target arginine. This indicates that PRMT6 recognises the RG motif rather than the RGG motif. We further confirm this preference for the RG motif on another PRMT6 substrate, histone H4R3. This broad specificity and recognition of RG rather than RGG are distinctive among the PRMT family and has implications for the development of drugs to selectively target PRMT6. DATABASES: Panorama Public (https://panoramaweb.org/PRMT6motif.url); ProteomeXchange (PXD016711).
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Affiliation(s)
- Joshua J Hamey
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Sinja Rakow
- Institute for Molecular Biology and Tumor Research (IMT), Philipps-University Marburg, Germany
| | - Caroline Bouchard
- Institute for Molecular Biology and Tumor Research (IMT), Philipps-University Marburg, Germany
| | - Johanna M Senst
- Department of Pharmaceutical Chemistry, Philipps-University Marburg, Germany
| | - Peter Kolb
- Department of Pharmaceutical Chemistry, Philipps-University Marburg, Germany
| | - Uta-Maria Bauer
- Institute for Molecular Biology and Tumor Research (IMT), Philipps-University Marburg, Germany
| | - Marc R Wilkins
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Gene Hart-Smith
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia.,Department of Molecular Sciences, Macquarie University, Sydney, NSW, Australia
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