1
|
Levites Y, Dammer EB, Ran Y, Tsering W, Duong D, Abreha M, Gadhavi J, Lolo K, Trejo-Lopez J, Phillips JL, Iturbe A, Erqiuzi A, Moore BD, Ryu D, Natu A, Dillon KD, Torrellas J, Moran C, Ladd TB, Afroz KF, Islam T, Jagirdar J, Funk CC, Robinson M, Borchelt DR, Ertekin-Taner N, Kelly JW, Heppner FL, Johnson EC, McFarland K, Levey AL, Prokop S, Seyfried NT, Golde TE. Aβ Amyloid Scaffolds the Accumulation of Matrisome and Additional Proteins in Alzheimer's Disease. bioRxiv 2023:2023.11.29.568318. [PMID: 38076912 PMCID: PMC10705437 DOI: 10.1101/2023.11.29.568318] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/14/2024]
Abstract
We report a highly significant correlation in brain proteome changes between Alzheimers disease (AD) and CRND8 APP695NL/F transgenic mice. However, integrating protein changes observed in the CRND8 mice with co-expression networks derived from human AD, reveals both conserved and divergent module changes. For the most highly conserved module (M42, matrisome) we find many proteins accumulate in plaques, cerebrovascular amyloid (CAA), dystrophic processes, or a combination thereof. Overexpression of two M42 proteins, midkine (Mdk) and pleiotrophin (PTN), in CRND8 mice brains leads to increased accumulation of A β ; in plaques and in CAA; further, recombinant MDK and PTN enhance A β ; aggregation into amyloid. Multiple M42 proteins, annotated as heparan sulfate binding proteins, bind to fibrillar A β 42 and a non-human amyloid fibril in vitro. Supporting this binding data, MDK and PTN co-accumulate with transthyretin (TTR) amyloid in the heart and islet amyloid polypeptide (IAPP) amyloid in the pancreas. Our findings establish several critical insights. Proteomic changes in modules observed in human AD brains define an A β ; amyloid responsome that is well conserved from mouse model to human. Further, distinct amyloid structures may serve as scaffolds, facilitating the co-accumulation of proteins with signaling functions. We hypothesize that this co-accumulation may contribute to downstream pathological sequalae. Overall, this contextualized understanding of proteomic changes and their interplay with amyloid deposition provides valuable insights into the complexity of AD pathogenesis and potential biomarkers and therapeutic targets.
Collapse
|
2
|
Deyts C, Clutter M, Pierce N, Chakrabarty P, Ladd TB, Goddi A, Rosario AM, Cruz P, Vetrivel K, Wagner SL, Thinakaran G, Golde TE, Parent AT. APP-Mediated Signaling Prevents Memory Decline in Alzheimer's Disease Mouse Model. Cell Rep 2020; 27:1345-1355.e6. [PMID: 31042463 DOI: 10.1016/j.celrep.2019.03.087] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [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: 05/03/2018] [Revised: 02/11/2019] [Accepted: 03/22/2019] [Indexed: 01/04/2023] Open
Abstract
Amyloid precursor protein (APP) and its metabolites play key roles in Alzheimer's disease (AD) pathophysiology. Whereas short amyloid-β (Aβ) peptides derived from APP are pathogenic, the APP holoprotein serves multiple purposes in the nervous system through its cell adhesion and receptor-like properties. Our studies focused on the signaling mediated by the APP cytoplasmic tail. We investigated whether sustained APP signaling during brain development might favor neuronal plasticity and memory process through a direct interaction with the heterotrimeric G-protein subunit GαS (stimulatory G-protein alpha subunit). Our results reveal that APP possesses autonomous regulatory capacity within its intracellular domain that promotes APP cell surface residence, precludes Aβ production, facilitates axodendritic development, and preserves cellular substrates of memory. Altogether, these events contribute to strengthening cognitive functions and are sufficient to modify the course of AD pathology.
Collapse
Affiliation(s)
- Carole Deyts
- Department of Neurobiology, The University of Chicago, 924 East 57th Street, Chicago, IL 60637, USA
| | - Mary Clutter
- Department of Neurobiology, The University of Chicago, 924 East 57th Street, Chicago, IL 60637, USA
| | - Nicholas Pierce
- Department of Neurobiology, The University of Chicago, 924 East 57th Street, Chicago, IL 60637, USA
| | - Paramita Chakrabarty
- Department of Neuroscience, Center for Translational Research in Neurodegenerative Disease, and McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA
| | - Thomas B Ladd
- Department of Neuroscience, Center for Translational Research in Neurodegenerative Disease, and McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA
| | - Anna Goddi
- Department of Neurobiology, The University of Chicago, 924 East 57th Street, Chicago, IL 60637, USA
| | - Awilda M Rosario
- Department of Neuroscience, Center for Translational Research in Neurodegenerative Disease, and McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA
| | - Pedro Cruz
- Department of Neuroscience, Center for Translational Research in Neurodegenerative Disease, and McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA
| | - Kulandaivelu Vetrivel
- Department of Neurobiology, The University of Chicago, 924 East 57th Street, Chicago, IL 60637, USA
| | - Steven L Wagner
- Department of Neurosciences, University of California San Diego, La Jolla, CA 92093, USA; Veterans Affairs San Diego Healthcare System, La Jolla, CA 92161, USA
| | - Gopal Thinakaran
- Department of Neurobiology, The University of Chicago, 924 East 57th Street, Chicago, IL 60637, USA
| | - Todd E Golde
- Department of Neuroscience, Center for Translational Research in Neurodegenerative Disease, and McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA
| | - Angèle T Parent
- Department of Neurobiology, The University of Chicago, 924 East 57th Street, Chicago, IL 60637, USA.
| |
Collapse
|
3
|
Lessard CB, Rodriguez E, Ladd TB, Minter LM, Osborne BA, Miele L, Golde TE, Ran Y. γ-Secretase modulators exhibit selectivity for modulation of APP cleavage but inverse γ-secretase modulators do not. Alzheimers Res Ther 2020; 12:61. [PMID: 32430033 PMCID: PMC7236921 DOI: 10.1186/s13195-020-00622-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Accepted: 04/27/2020] [Indexed: 12/13/2022]
Abstract
Background γ-Secretase is a multiprotein protease that cleaves amyloid protein precursor (APP) and other type I transmembrane proteins. It has two catalytic subunits, presenilins 1 and 2 (PS1 and 2). In our previous report, we observed subtle differences in PS1- and PS2-mediated cleavages of select substrates and slightly different potencies of PS1 versus PS2 inhibition for select γ-secretase inhibitors (GSIs) on various substrates. In this study, we investigated whether γ-secretase modulators (GSMs) and inverse γ-secretase modulators (iGSMs) modulate γ-secretase processivity using multiple different substrates. We next used HEK 293T cell lines in which PSEN1 or PSEN2 was selectively knocked out to investigate processivity and response to GSMs and iGSMs. Methods For cell-free γ-secretase cleavage assay, recombinant substrates were incubated with CHAPSO-solubilized CHO or HEK 293T cell membrane with GSMs or iGSMs in suitable buffer. For cell-based assay, cDNA encoding substrates were transfected into HEK 293T cells. Cells were then treated with GSMs or iGSMs, and conditioned media were collected. Aβ and Aβ-like peptide production from cell-free and cell-based assay were measured by ELISA and mass spectrometry. Result These studies demonstrated that GSMs are highly selective for effects on APP, whereas iGSMs have a more promiscuous effect on many substrates. Surprisingly, iGSMs actually appear to act as like GSIs on select substrates. The data with PSEN1 or PSEN2 knocked out HEK 293T reveal that PS1 has higher processivity and response to GSMs than PS2, but PS2 has higher response to iGSM. Conclusion Collectively, these data indicate that GSMs are likely to have limited target-based toxicity. In addition, they show that iGSMs may act as substrate-selective GSIs providing a potential new route to identify leads for substrate-selective inhibitors of certain γ-secretase-mediated signaling events. With growing concerns that long-term β-secretase inhibitor is limited by target-based toxicities, such data supports continued development of GSMs as AD prophylactics.
Collapse
Affiliation(s)
- Christian B Lessard
- Department of Neuroscience and Neurology, Center for Translational Research in Neurodegenerative Disease, and McKnight Brain Institute, College of Medicine, University of Florida, 1275 Center Drive, PO Box 100159, Gainesville, FL, 32610, USA
| | - Edgardo Rodriguez
- Department of Pharmacology and Therapeutics, Center for Translational Research in Neurodegenerative Disease, and McKnight Brain Institute, University of Florida, Gainesville, FL, 32610, USA
| | - Thomas B Ladd
- Department of Neuroscience and Neurology, Center for Translational Research in Neurodegenerative Disease, and McKnight Brain Institute, College of Medicine, University of Florida, 1275 Center Drive, PO Box 100159, Gainesville, FL, 32610, USA
| | - Lisa M Minter
- Department of Veterinary and Animal Sciences, Center for Bioactive Delivery, Institute for Applied Life Sciences, and Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, MA, 01003, USA
| | - Barbara A Osborne
- Department of Veterinary and Animal Sciences, Center for Bioactive Delivery, Institute for Applied Life Sciences, and Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, MA, 01003, USA
| | - Lucio Miele
- Department of Genetics and Stanley S. Scott Cancer Center, Louisiana State University Health Sciences Center, New Orleans, LA, 70112, USA
| | - Todd E Golde
- Department of Neuroscience and Neurology, Center for Translational Research in Neurodegenerative Disease, and McKnight Brain Institute, College of Medicine, University of Florida, 1275 Center Drive, PO Box 100159, Gainesville, FL, 32610, USA.
| | - Yong Ran
- Department of Neuroscience and Neurology, Center for Translational Research in Neurodegenerative Disease, and McKnight Brain Institute, College of Medicine, University of Florida, 1275 Center Drive, PO Box 100159, Gainesville, FL, 32610, USA.
| |
Collapse
|
4
|
Chakrabarty P, Li A, Ladd TB, Strickland MR, Koller EJ, Burgess JD, Funk CC, Cruz PE, Allen M, Yaroshenko M, Wang X, Younkin C, Reddy J, Lohrer B, Mehrke L, Moore BD, Liu X, Ceballos-Diaz C, Rosario AM, Medway C, Janus C, Li HD, Dickson DW, Giasson BI, Price ND, Younkin SG, Ertekin-Taner N, Golde TE. TLR5 decoy receptor as a novel anti-amyloid therapeutic for Alzheimer's disease. J Exp Med 2019; 215:2247-2264. [PMID: 30158114 PMCID: PMC6122970 DOI: 10.1084/jem.20180484] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 05/09/2018] [Accepted: 05/09/2018] [Indexed: 12/22/2022] Open
Abstract
Chakrabarty et al. show that human TLR5 ectodomain reduces amyloid β (Aβ) plaques by direct interaction with Aβ, demonstrating the feasibility of such immune decoy receptor strategies as potential biotherapies in Alzheimer’s disease. There is considerable interest in harnessing innate immunity to treat Alzheimer’s disease (AD). Here, we explore whether a decoy receptor strategy using the ectodomain of select TLRs has therapeutic potential in AD. AAV-mediated expression of human TLR5 ectodomain (sTLR5) alone or fused to human IgG4 Fc (sTLR5Fc) results in robust attenuation of amyloid β (Aβ) accumulation in a mouse model of Alzheimer-type Aβ pathology. sTLR5Fc binds to oligomeric and fibrillar Aβ with high affinity, forms complexes with Aβ, and blocks Aβ toxicity. Oligomeric and fibrillar Aβ modulates flagellin-mediated activation of human TLR5 but does not, by itself, activate TLR5 signaling. Genetic analysis shows that rare protein coding variants in human TLR5 may be associated with a reduced risk of AD. Further, transcriptome analysis shows altered TLR gene expression in human AD. Collectively, our data suggest that TLR5 decoy receptor–based biologics represent a novel and safe Aβ-selective class of biotherapy in AD.
Collapse
Affiliation(s)
- Paramita Chakrabarty
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, Gainesville, FL .,McKnight Brain Institute, University of Florida, Gainesville, FL
| | - Andrew Li
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, Gainesville, FL
| | - Thomas B Ladd
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, Gainesville, FL
| | - Michael R Strickland
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, Gainesville, FL
| | - Emily J Koller
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, Gainesville, FL
| | | | | | - Pedro E Cruz
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, Gainesville, FL
| | - Mariet Allen
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL
| | - Mariya Yaroshenko
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, Gainesville, FL
| | - Xue Wang
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL
| | - Curtis Younkin
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL
| | - Joseph Reddy
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL
| | | | - Leonie Mehrke
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL
| | - Brenda D Moore
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, Gainesville, FL
| | - Xuefei Liu
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, Gainesville, FL
| | - Carolina Ceballos-Diaz
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, Gainesville, FL
| | - Awilda M Rosario
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, Gainesville, FL
| | | | - Christopher Janus
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, Gainesville, FL
| | | | | | - Benoit I Giasson
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, Gainesville, FL.,McKnight Brain Institute, University of Florida, Gainesville, FL
| | | | | | - Nilüfer Ertekin-Taner
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL.,Department of Neurology, Mayo Clinic, Jacksonville, FL
| | - Todd E Golde
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, Gainesville, FL .,McKnight Brain Institute, University of Florida, Gainesville, FL
| |
Collapse
|
5
|
Futch HS, McFarland KN, Moore BD, Kuhn MZ, Giasson BI, Ladd TB, Scott KA, Shapiro MR, Nosacka RL, Goodwin MS, Ran Y, Cruz PE, Ryu DH, Croft CL, Levites Y, Janus C, Chakrabarty P, Judge AR, Brusko TM, de Kloet AD, Krause EG, Golde TE. An anti-CRF antibody suppresses the HPA axis and reverses stress-induced phenotypes. J Exp Med 2019; 216:2479-2491. [PMID: 31467037 PMCID: PMC6829597 DOI: 10.1084/jem.20190430] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 06/05/2019] [Accepted: 08/16/2019] [Indexed: 12/20/2022] Open
Abstract
A high-affinity monoclonal antibody (CTRND05) targeting corticotropin-releasing factor (CRF) blocks stress-induced corticosterone increases, counteracts effects of chronic variable stress, and induces other phenotypes consistent with suppression of the HPA axis. Hypothalamic–pituitary–adrenal (HPA) axis dysfunction contributes to numerous human diseases and disorders. We developed a high-affinity monoclonal antibody, CTRND05, targeting corticotropin-releasing factor (CRF). In mice, CTRND05 blocks stress-induced corticosterone increases, counteracts effects of chronic variable stress, and induces other phenotypes consistent with suppression of the HPA axis. CTRND05 induces skeletal muscle hypertrophy and increases lean body mass, effects not previously reported with small-molecule HPA-targeting pharmacologic agents. Multiorgan transcriptomics demonstrates broad HPA axis target engagement through altering levels of known HPA-responsive transcripts such as Fkbp5 and Myostatin and reveals novel HPA-responsive pathways such as the Apelin-Apelin receptor system. These studies demonstrate the therapeutic potential of CTRND05 as a suppressor of the HPA axis and serve as an exemplar of a potentially broader approach to target neuropeptides with immunotherapies, as both pharmacologic tools and novel therapeutics.
Collapse
Affiliation(s)
- Hunter S Futch
- McKnight Brain Institute, Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience and Neurology, College of Medicine, University of Florida, Gainesville, FL
| | - Karen N McFarland
- McKnight Brain Institute, Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience and Neurology, College of Medicine, University of Florida, Gainesville, FL
| | - Brenda D Moore
- McKnight Brain Institute, Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience and Neurology, College of Medicine, University of Florida, Gainesville, FL
| | - M Zino Kuhn
- McKnight Brain Institute, Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience and Neurology, College of Medicine, University of Florida, Gainesville, FL
| | - Benoit I Giasson
- McKnight Brain Institute, Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience and Neurology, College of Medicine, University of Florida, Gainesville, FL
| | - Thomas B Ladd
- McKnight Brain Institute, Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience and Neurology, College of Medicine, University of Florida, Gainesville, FL
| | - Karen A Scott
- McKnight Brain Institute, Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, FL
| | - Melanie R Shapiro
- Diabetes Institute, Department of Pathology, Immunology and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, FL
| | - Rachel L Nosacka
- Department of Physical Therapy, College of Public Health and Health Professions, University of Florida, Gainesville, FL
| | - Marshall S Goodwin
- McKnight Brain Institute, Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience and Neurology, College of Medicine, University of Florida, Gainesville, FL
| | - Yong Ran
- McKnight Brain Institute, Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience and Neurology, College of Medicine, University of Florida, Gainesville, FL
| | - Pedro E Cruz
- McKnight Brain Institute, Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience and Neurology, College of Medicine, University of Florida, Gainesville, FL
| | - Daniel H Ryu
- McKnight Brain Institute, Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience and Neurology, College of Medicine, University of Florida, Gainesville, FL
| | - Cara L Croft
- McKnight Brain Institute, Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience and Neurology, College of Medicine, University of Florida, Gainesville, FL
| | - Yona Levites
- McKnight Brain Institute, Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience and Neurology, College of Medicine, University of Florida, Gainesville, FL
| | - Christopher Janus
- McKnight Brain Institute, Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience and Neurology, College of Medicine, University of Florida, Gainesville, FL
| | - Paramita Chakrabarty
- McKnight Brain Institute, Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience and Neurology, College of Medicine, University of Florida, Gainesville, FL
| | - Andrew R Judge
- Department of Physical Therapy, College of Public Health and Health Professions, University of Florida, Gainesville, FL
| | - Todd M Brusko
- Diabetes Institute, Department of Pathology, Immunology and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, FL
| | - Annette D de Kloet
- McKnight Brain Institute, Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, FL
| | - Eric G Krause
- McKnight Brain Institute, Department of Physiology and Functional Genomics, College of Medicine, University of Florida, Gainesville, FL
| | - Todd E Golde
- McKnight Brain Institute, Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience and Neurology, College of Medicine, University of Florida, Gainesville, FL
| |
Collapse
|
6
|
Lessard CB, Malnik SL, Zhou Y, Ladd TB, Cruz PE, Ran Y, Mahan TE, Chakrabaty P, Holtzman DM, Ulrich JD, Colonna M, Golde TE. High-affinity interactions and signal transduction between Aβ oligomers and TREM2. EMBO Mol Med 2019; 10:emmm.201809027. [PMID: 30341064 PMCID: PMC6220267 DOI: 10.15252/emmm.201809027] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Rare coding variants in the triggering receptor expressed on myeloid cells 2 (TREM2) are associated with increased risk for Alzheimer's disease (AD), but how they confer this risk remains uncertain. We assessed binding of TREM2, AD‐associated TREM2 variants to various forms of Aβ and APOE in multiple assays. TREM2 interacts directly with various forms of Aβ, with highest affinity interactions observed between TREM2 and soluble Aβ42 oligomers. High‐affinity binding of TREM2 to Aβ oligomers is characterized by very slow dissociation. Pre‐incubation with Aβ is shown to block the interaction of APOE. In cellular assays, AD‐associated variants of TREM2 reduced the amount of Aβ42 internalized, and in NFAT assay, the R47H and R62H variants decreased NFAT signaling activity in response to Aβ42. These studies demonstrate i) a high‐affinity interaction between TREM2 and Aβ oligomers that can block interaction with another TREM2 ligand and ii) that AD‐associated TREM2 variants bind Aβ with equivalent affinity but show loss of function in terms of signaling and Aβ internalization.
Collapse
Affiliation(s)
- Christian B Lessard
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, Gainesville, FL, USA
| | - Samuel L Malnik
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, Gainesville, FL, USA
| | - Yingyue Zhou
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA
| | - Thomas B Ladd
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, Gainesville, FL, USA
| | - Pedro E Cruz
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, Gainesville, FL, USA
| | - Yong Ran
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, Gainesville, FL, USA
| | - Thomas E Mahan
- Department of Neurology, Hope Center for Neurological Disorders, Knight ADRC, Washington University School of Medicine, St. Louis, MO, USA
| | - Paramita Chakrabaty
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, Gainesville, FL, USA.,McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - David M Holtzman
- Department of Neurology, Hope Center for Neurological Disorders, Knight ADRC, Washington University School of Medicine, St. Louis, MO, USA
| | - Jason D Ulrich
- Department of Neurology, Hope Center for Neurological Disorders, Knight ADRC, Washington University School of Medicine, St. Louis, MO, USA
| | - Marco Colonna
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA
| | - Todd E Golde
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, Gainesville, FL, USA .,McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| |
Collapse
|
7
|
Lessard CB, Rodriguez E, Ladd TB, Minter LM, Osborne BA, Miele L, Golde TE, Ran Y. Individual and combined presenilin 1 and 2 knockouts reveal that both have highly overlapping functions in HEK293T cells. J Biol Chem 2019; 294:11276-11285. [PMID: 31167792 DOI: 10.1074/jbc.ra119.008041] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [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: 02/15/2019] [Revised: 05/30/2019] [Indexed: 01/13/2023] Open
Abstract
Presenilins 1 and 2 (PS1 and 2) are the catalytic subunits of γ-secretase, a multiprotein protease that cleaves amyloid protein precursor and other type I transmembrane proteins. Previous studies with mouse models or cells have indicated differences in PS1 and PS2 functions. We have recently reported that clinical γ-secretase inhibitors (GSIs), initially developed to manage Alzheimer's disease and now being considered for other therapeutic interventions, are both pharmacologically and functionally distinct. Here, using CRISPR/Cas9-based gene editing, we established human HEK 293T cell lines in which endogenous PS1, PS2, or both have been knocked out. Using these knockout lines to examine differences in PS1- and PS2-mediated cleavage events, we confirmed that PS2 generates more intracellular β-amyloid than does PS1. Moreover, we observed subtle differences in PS1- and PS2-mediated cleavages of select substrates. In exploring the question of whether differences in activity among clinical GSIs could be attributed to differential inhibition of PS1 or PS2, we noted that select GSIs inhibit PS1 and PS2 activities on specific substrates with slightly different potencies. We also found that endoproteolysis of select PS1 FAD-linked variants in human cells is more efficient than what has been previously reported for mouse cell lines. Overall, these results obtained with HEK293T cells suggest that selective PS1 or PS2 inhibition by a given GSI does not explain the previously observed differences in functional and pharmacological properties among various GSIs.
Collapse
Affiliation(s)
- Christian B Lessard
- Department of Neuroscience and Neurology, Center for Translational Research in Neurodegenerative Disease, and McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, Florida 32610
| | - Edgardo Rodriguez
- Department of Pharmacology and Therapeutics, Center for Translational Research in Neurodegenerative Disease, and McKnight Brain Institute, University of Florida, Gainesville, Florida 32610
| | - Thomas B Ladd
- Department of Neuroscience and Neurology, Center for Translational Research in Neurodegenerative Disease, and McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, Florida 32610
| | - Lisa M Minter
- Department of Veterinary and Animal Sciences, Center for Bioactive Delivery, Institute for Applied Life Sciences, and Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, Massachusetts 01003
| | - Barbara A Osborne
- Department of Veterinary and Animal Sciences, Center for Bioactive Delivery, Institute for Applied Life Sciences, and Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, Massachusetts 01003
| | - Lucio Miele
- Department of Genetics and Stanley S. Scott Cancer Center, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112
| | - Todd E Golde
- Department of Neuroscience and Neurology, Center for Translational Research in Neurodegenerative Disease, and McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, Florida 32610
| | - Yong Ran
- Department of Neuroscience and Neurology, Center for Translational Research in Neurodegenerative Disease, and McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, Florida 32610
| |
Collapse
|
8
|
Moore BD, Martin J, de Mena L, Sanchez J, Cruz PE, Ceballos-Diaz C, Ladd TB, Ran Y, Levites Y, Kukar TL, Kurian JJ, McKenna R, Koo EH, Borchelt DR, Janus C, Rincon-Limas D, Fernandez-Funez P, Golde TE. Short Aβ peptides attenuate Aβ42 toxicity in vivo. J Exp Med 2017; 215:283-301. [PMID: 29208777 PMCID: PMC5748850 DOI: 10.1084/jem.20170600] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 08/18/2017] [Accepted: 10/04/2017] [Indexed: 01/05/2023] Open
Abstract
Data demonstrate that short amyloid-β (Aβ) peptides are not toxic in vivo and can partially block toxicity associated with Aβ42 accumulation. Moore et al. further validate the use of γ-secretase modulators that lower Aβ42 and increase short Aβs as potential Alzheimer’s disease therapeutics. Processing of amyloid-β (Aβ) precursor protein (APP) by γ-secretase produces multiple species of Aβ: Aβ40, short Aβ peptides (Aβ37–39), and longer Aβ peptides (Aβ42–43). γ-Secretase modulators, a class of Alzheimer’s disease therapeutics, reduce production of the pathogenic Aβ42 but increase the relative abundance of short Aβ peptides. To evaluate the pathological relevance of these peptides, we expressed Aβ36–40 and Aβ42–43 in Drosophila melanogaster to evaluate inherent toxicity and potential modulatory effects on Aβ42 toxicity. In contrast to Aβ42, the short Aβ peptides were not toxic and, when coexpressed with Aβ42, were protective in a dose-dependent fashion. In parallel, we explored the effects of recombinant adeno-associated virus–mediated expression of Aβ38 and Aβ40 in mice. When expressed in nontransgenic mice at levels sufficient to drive Aβ42 deposition, Aβ38 and Aβ40 did not deposit or cause behavioral alterations. These studies indicate that treatments that lower Aβ42 by raising the levels of short Aβ peptides could attenuate the toxic effects of Aβ42.
Collapse
Affiliation(s)
- Brenda D Moore
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, Gainesville, FL.,McKnight Brain Institute, University of Florida, Gainesville, FL
| | - Jason Martin
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, Gainesville, FL.,McKnight Brain Institute, University of Florida, Gainesville, FL
| | - Lorena de Mena
- McKnight Brain Institute, University of Florida, Gainesville, FL.,Department of Neurology, University of Florida, Gainesville, FL
| | - Jonatan Sanchez
- McKnight Brain Institute, University of Florida, Gainesville, FL.,Department of Neurology, University of Florida, Gainesville, FL
| | - Pedro E Cruz
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, Gainesville, FL.,McKnight Brain Institute, University of Florida, Gainesville, FL
| | - Carolina Ceballos-Diaz
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, Gainesville, FL.,McKnight Brain Institute, University of Florida, Gainesville, FL
| | - Thomas B Ladd
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, Gainesville, FL.,McKnight Brain Institute, University of Florida, Gainesville, FL
| | - Yong Ran
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, Gainesville, FL.,McKnight Brain Institute, University of Florida, Gainesville, FL
| | - Yona Levites
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, Gainesville, FL.,McKnight Brain Institute, University of Florida, Gainesville, FL
| | - Thomas L Kukar
- Department of Pharmacology and Neurology, Emory University School of Medicine, Atlanta, GA
| | - Justin J Kurian
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL
| | - Robert McKenna
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL
| | - Edward H Koo
- Department of Neuroscience, University of California, San Diego, La Jolla, CA
| | - David R Borchelt
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, Gainesville, FL.,McKnight Brain Institute, University of Florida, Gainesville, FL
| | - Christopher Janus
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, Gainesville, FL.,McKnight Brain Institute, University of Florida, Gainesville, FL
| | - Diego Rincon-Limas
- McKnight Brain Institute, University of Florida, Gainesville, FL.,Department of Neurology, University of Florida, Gainesville, FL
| | - Pedro Fernandez-Funez
- Department of Biomedical Sciences, University of Minnesota School of Medicine, Duluth, MN
| | - Todd E Golde
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, Gainesville, FL .,McKnight Brain Institute, University of Florida, Gainesville, FL
| |
Collapse
|
9
|
Levey DF, Niculescu EM, Le-Niculescu H, Dainton HL, Phalen PL, Ladd TB, Weber H, Belanger E, Graham DL, Khan FN, Vanipenta NP, Stage EC, Ballew A, Yard M, Gelbart T, Shekhar A, Schork NJ, Kurian SM, Sandusky GE, Salomon DR, Niculescu AB. Towards understanding and predicting suicidality in women: biomarkers and clinical risk assessment. Mol Psychiatry 2016; 21:768-85. [PMID: 27046645 DOI: 10.1038/mp.2016.31] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2015] [Revised: 01/27/2016] [Accepted: 02/11/2016] [Indexed: 02/06/2023]
Abstract
Women are under-represented in research on suicidality to date. Although women have a lower rate of suicide completion than men, due in part to the less-violent methods used, they have a higher rate of suicide attempts. Our group has previously identified genomic (blood gene expression biomarkers) and clinical information (apps) predictors for suicidality in men. We now describe pilot studies in women. We used a powerful within-participant discovery approach to identify genes that change in expression between no suicidal ideation (no SI) and high suicidal ideation (high SI) states (n=12 participants out of a cohort of 51 women psychiatric participants followed longitudinally, with diagnoses of bipolar disorder, depression, schizoaffective disorder and schizophrenia). We then used a Convergent Functional Genomics (CFG) approach to prioritize the candidate biomarkers identified in the discovery step by using all the prior evidence in the field. Next, we validated for suicidal behavior the top-ranked biomarkers for SI, in a demographically matched cohort of women suicide completers from the coroner's office (n=6), by assessing which markers were stepwise changed from no SI to high SI to suicide completers. We then tested the 50 biomarkers that survived Bonferroni correction in the validation step, as well as top increased and decreased biomarkers from the discovery and prioritization steps, in a completely independent test cohort of women psychiatric disorder participants for prediction of SI (n=33) and in a future follow-up cohort of psychiatric disorder participants for prediction of psychiatric hospitalizations due to suicidality (n=24). Additionally, we examined how two clinical instruments in the form of apps, Convergent Functional Information for Suicidality (CFI-S) and Simplified Affective State Scale (SASS), previously tested in men, perform in women. The top CFI-S item distinguishing high SI from no SI states was the chronic stress of social isolation. We then showed how the clinical information apps combined with the 50 validated biomarkers into a broad predictor (UP-Suicide), our apriori primary end point, predicts suicidality in women. UP-Suicide had a receiver-operating characteristic (ROC) area under the curve (AUC) of 82% for predicting SI and an AUC of 78% for predicting future hospitalizations for suicidality. Some of the individual components of the UP-Suicide showed even better results. SASS had an AUC of 81% for predicting SI, CFI-S had an AUC of 84% and the combination of the two apps had an AUC of 87%. The top biomarker from our sequential discovery, prioritization and validation steps, BCL2, predicted future hospitalizations due to suicidality with an AUC of 89%, and the panel of 50 validated biomarkers (BioM-50) predicted future hospitalizations due to suicidality with an AUC of 94%. The best overall single blood biomarker for predictions was PIK3C3 with an AUC of 65% for SI and an AUC of 90% for future hospitalizations. Finally, we sought to understand the biology of the biomarkers. BCL2 and GSK3B, the top CFG scoring validated biomarkers, as well as PIK3C3, have anti-apoptotic and neurotrophic effects, are decreased in expression in suicidality and are known targets of the anti-suicidal mood stabilizer drug lithium, which increases their expression and/or activity. Circadian clock genes were overrepresented among the top markers. Notably, PER1, increased in expression in suicidality, had an AUC of 84% for predicting future hospitalizations, and CSNK1A1, decreased in expression, had an AUC of 96% for predicting future hospitalizations. Circadian clock abnormalities are related to mood disorder, and sleep abnormalities have been implicated in suicide. Docosahexaenoic acid signaling was one of the top biological pathways overrepresented in validated biomarkers, which is of interest given the potential therapeutic and prophylactic benefits of omega-3 fatty acids. Some of the top biomarkers from the current work in women showed co-directionality of change in expression with our previous work in men, whereas others had changes in opposite directions, underlying the issue of biological context and differences in suicidality between the two genders. With this study, we begin to shed much needed light in the area of female suicidality, identify useful objective predictors and help understand gender commonalities and differences. During the conduct of the study, one participant committed suicide. In retrospect, when the analyses were completed, her UP-Suicide risk prediction score was at the 100 percentile of all participants tested.
Collapse
Affiliation(s)
- D F Levey
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA.,Stark Neuroscience Research Institute, Indiana University School of Medicine, Indianapolis, IN, USA
| | - E M Niculescu
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - H Le-Niculescu
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - H L Dainton
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - P L Phalen
- Indianapolis Veterans' Affairs Medical Center, Indianapolis, IN, USA
| | - T B Ladd
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA.,Stark Neuroscience Research Institute, Indiana University School of Medicine, Indianapolis, IN, USA
| | - H Weber
- Indianapolis Veterans' Affairs Medical Center, Indianapolis, IN, USA
| | - E Belanger
- Indianapolis Veterans' Affairs Medical Center, Indianapolis, IN, USA
| | - D L Graham
- Indianapolis Veterans' Affairs Medical Center, Indianapolis, IN, USA
| | - F N Khan
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - N P Vanipenta
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - E C Stage
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA.,Stark Neuroscience Research Institute, Indiana University School of Medicine, Indianapolis, IN, USA
| | - A Ballew
- Marion County Coroner's Office, Indianapolis, IN, USA
| | - M Yard
- Indiana Center for Biomarker Research in Neuropsychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - T Gelbart
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - A Shekhar
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - N J Schork
- J. Craig Venter Institute, La Jolla, CA, USA
| | - S M Kurian
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - G E Sandusky
- Indiana Center for Biomarker Research in Neuropsychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - D R Salomon
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - A B Niculescu
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA.,Stark Neuroscience Research Institute, Indiana University School of Medicine, Indianapolis, IN, USA.,Indianapolis Veterans' Affairs Medical Center, Indianapolis, IN, USA
| |
Collapse
|
10
|
Niculescu AB, Levey DF, Phalen PL, Le-Niculescu H, Dainton HD, Jain N, Belanger E, James A, George S, Weber H, Graham DL, Schweitzer R, Ladd TB, Learman R, Niculescu EM, Vanipenta NP, Khan FN, Mullen J, Shankar G, Cook S, Humbert C, Ballew A, Yard M, Gelbart T, Shekhar A, Schork NJ, Kurian SM, Sandusky GE, Salomon DR. Understanding and predicting suicidality using a combined genomic and clinical risk assessment approach. Mol Psychiatry 2015; 20:1266-85. [PMID: 26283638 PMCID: PMC4759104 DOI: 10.1038/mp.2015.112] [Citation(s) in RCA: 102] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Revised: 06/25/2015] [Accepted: 06/29/2015] [Indexed: 12/26/2022]
Abstract
Worldwide, one person dies every 40 seconds by suicide, a potentially preventable tragedy. A limiting step in our ability to intervene is the lack of objective, reliable predictors. We have previously provided proof of principle for the use of blood gene expression biomarkers to predict future hospitalizations due to suicidality, in male bipolar disorder participants. We now generalize the discovery, prioritization, validation, and testing of such markers across major psychiatric disorders (bipolar disorder, major depressive disorder, schizoaffective disorder, and schizophrenia) in male participants, to understand commonalities and differences. We used a powerful within-participant discovery approach to identify genes that change in expression between no suicidal ideation and high suicidal ideation states (n=37 participants out of a cohort of 217 psychiatric participants followed longitudinally). We then used a convergent functional genomics (CFG) approach with existing prior evidence in the field to prioritize the candidate biomarkers identified in the discovery step. Next, we validated the top biomarkers from the prioritization step for relevance to suicidal behavior, in a demographically matched cohort of suicide completers from the coroner's office (n=26). The biomarkers for suicidal ideation only are enriched for genes involved in neuronal connectivity and schizophrenia, the biomarkers also validated for suicidal behavior are enriched for genes involved in neuronal activity and mood. The 76 biomarkers that survived Bonferroni correction after validation for suicidal behavior map to biological pathways involved in immune and inflammatory response, mTOR signaling and growth factor regulation. mTOR signaling is necessary for the effects of the rapid-acting antidepressant agent ketamine, providing a novel biological rationale for its possible use in treating acute suicidality. Similarly, MAOB, a target of antidepressant inhibitors, was one of the increased biomarkers for suicidality. We also identified other potential therapeutic targets or biomarkers for drugs known to mitigate suicidality, such as omega-3 fatty acids, lithium and clozapine. Overall, 14% of the top candidate biomarkers also had evidence for involvement in psychological stress response, and 19% for involvement in programmed cell death/cellular suicide (apoptosis). It may be that in the face of adversity (stress), death mechanisms are turned on at a cellular (apoptosis) and organismal level. Finally, we tested the top increased and decreased biomarkers from the discovery for suicidal ideation (CADM1, CLIP4, DTNA, KIF2C), prioritization with CFG for prior evidence (SAT1, SKA2, SLC4A4), and validation for behavior in suicide completers (IL6, MBP, JUN, KLHDC3) steps in a completely independent test cohort of psychiatric participants for prediction of suicidal ideation (n=108), and in a future follow-up cohort of psychiatric participants (n=157) for prediction of psychiatric hospitalizations due to suicidality. The best individual biomarker across psychiatric diagnoses for predicting suicidal ideation was SLC4A4, with a receiver operating characteristic (ROC) area under the curve (AUC) of 72%. For bipolar disorder in particular, SLC4A4 predicted suicidal ideation with an AUC of 93%, and future hospitalizations with an AUC of 70%. SLC4A4 is involved in brain extracellular space pH regulation. Brain pH has been implicated in the pathophysiology of acute panic attacks. We also describe two new clinical information apps, one for affective state (simplified affective state scale, SASS) and one for suicide risk factors (Convergent Functional Information for Suicide, CFI-S), and how well they predict suicidal ideation across psychiatric diagnoses (AUC of 85% for SASS, AUC of 89% for CFI-S). We hypothesized a priori, based on our previous work, that the integration of the top biomarkers and the clinical information into a universal predictive measure (UP-Suicide) would show broad-spectrum predictive ability across psychiatric diagnoses. Indeed, the UP-Suicide was able to predict suicidal ideation across psychiatric diagnoses with an AUC of 92%. For bipolar disorder, it predicted suicidal ideation with an AUC of 98%, and future hospitalizations with an AUC of 94%. Of note, both types of tests we developed (blood biomarkers and clinical information apps) do not require asking the individual assessed if they have thoughts of suicide, as individuals who are truly suicidal often do not share that information with clinicians. We propose that the widespread use of such risk prediction tests as part of routine or targeted healthcare assessments will lead to early disease interception followed by preventive lifestyle modifications and proactive treatment.
Collapse
Affiliation(s)
- A B Niculescu
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
- Stark Neuroscience Research Institute, Indiana University School of Medicine, Indianapolis, IN, USA
- Indianapolis VA Medical Center, Indianapolis, IN, USA
| | - D F Levey
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
- Stark Neuroscience Research Institute, Indiana University School of Medicine, Indianapolis, IN, USA
| | - P L Phalen
- Indianapolis VA Medical Center, Indianapolis, IN, USA
| | - H Le-Niculescu
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - H D Dainton
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - N Jain
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - E Belanger
- Indianapolis VA Medical Center, Indianapolis, IN, USA
| | - A James
- Indianapolis VA Medical Center, Indianapolis, IN, USA
| | - S George
- Indianapolis VA Medical Center, Indianapolis, IN, USA
| | - H Weber
- Indianapolis VA Medical Center, Indianapolis, IN, USA
| | - D L Graham
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - R Schweitzer
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - T B Ladd
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - R Learman
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - E M Niculescu
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - N P Vanipenta
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - F N Khan
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - J Mullen
- Advanced Biomedical IT Core, Indiana University School of Medicine, Indianapolis, IN, USA
| | - G Shankar
- Advanced Biomedical IT Core, Indiana University School of Medicine, Indianapolis, IN, USA
| | - S Cook
- Marion County Coroner's Office, Indianapolis, IN, USA
| | - C Humbert
- Marion County Coroner's Office, Indianapolis, IN, USA
| | - A Ballew
- Marion County Coroner's Office, Indianapolis, IN, USA
| | - M Yard
- INBRAIN, Indiana University School of Medicine, Indianapolis, IN, USA
| | - T Gelbart
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - A Shekhar
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - N J Schork
- J. Craig Venter Institute, La Jolla, CA, USA
| | - S M Kurian
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - G E Sandusky
- INBRAIN, Indiana University School of Medicine, Indianapolis, IN, USA
| | - D R Salomon
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA, USA
| |
Collapse
|
11
|
Rutherford NJ, Sacino AN, Brooks M, Ceballos-Diaz C, Ladd TB, Howard JK, Golde TE, Giasson BI. Studies of lipopolysaccharide effects on the induction of α-synuclein pathology by exogenous fibrils in transgenic mice. Mol Neurodegener 2015. [PMID: 26223783 PMCID: PMC4520273 DOI: 10.1186/s13024-015-0029-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Parkinson's disease (PD) is a progressive neurodegenerative disorder that is pathologically characterized by loss of dopaminergic neurons from the substantia nigra, the presence of aggregated α-synuclein (αS) and evidence of neuroinflammation. Experimental studies have shown that the cerebral injection of recombinant fibrillar αS, especially in αS transgenic mouse models, can induce the formation and spread of αS inclusion pathology. However, studies reporting this phenomenon did not consider the presence of lipopolysaccharide (LPS) in the injected αS, produced in E. coli, as a potential confound. The objectives of this study are to develop a method to remove the LPS contamination and investigate the differences in pathologies induced by αS containing LPS or αS highly purified of LPS. RESULTS AND CONCLUSIONS We were able to remove >99.5% of the LPS contamination from the αS preparations through the addition of a cation exchange step during purification. The αS pathology induced by injection of fibrils produced from αS containing LPS or purified of LPS, showed a similar distribution pattern; however, there was less spread into the cortex of the mice injected with αS containing higher levels of LPS. As previously reported, injection of αS fibrils could induce astrogliosis, and αS inclusions were present within astrocytes in mice injected with fibrils comprised of αS with or without cation exchange purification. Furthermore, we identified the presence of αS pathology in ependymal cells in both groups of mice, which suggests the involvement of a novel mechanism for spread in this model of αS pathology.
Collapse
Affiliation(s)
- Nicola J Rutherford
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, 1275 Center Drive, Room BMS J-483, PO Box 100159, Gainesville, FL, 32610, USA.
| | - Amanda N Sacino
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, 1275 Center Drive, Room BMS J-483, PO Box 100159, Gainesville, FL, 32610, USA.
| | - Mieu Brooks
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, 1275 Center Drive, Room BMS J-483, PO Box 100159, Gainesville, FL, 32610, USA.
| | - Carolina Ceballos-Diaz
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, 1275 Center Drive, Room BMS J-483, PO Box 100159, Gainesville, FL, 32610, USA.
| | - Thomas B Ladd
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, 1275 Center Drive, Room BMS J-483, PO Box 100159, Gainesville, FL, 32610, USA.
| | - Jasie K Howard
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, 1275 Center Drive, Room BMS J-483, PO Box 100159, Gainesville, FL, 32610, USA.
| | - Todd E Golde
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, 1275 Center Drive, Room BMS J-483, PO Box 100159, Gainesville, FL, 32610, USA.
| | - Benoit I Giasson
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, 1275 Center Drive, Room BMS J-483, PO Box 100159, Gainesville, FL, 32610, USA.
| |
Collapse
|
12
|
Jung JI, Price AR, Ladd TB, Ran Y, Park HJ, Ceballos-Diaz C, Smithson LA, Hochhaus G, Tang Y, Akula R, Ba S, Koo EH, Shapiro G, Felsenstein KM, Golde TE. Cholestenoic acid, an endogenous cholesterol metabolite, is a potent γ-secretase modulator. Mol Neurodegener 2015; 10:29. [PMID: 26169917 PMCID: PMC4501119 DOI: 10.1186/s13024-015-0021-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Accepted: 05/29/2015] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Amyloid-β (Aβ) 42 has been implicated as the initiating molecule in the pathogenesis of Alzheimer's disease (AD); thus, therapeutic strategies that target Aβ42 are of great interest. γ-Secretase modulators (GSMs) are small molecules that selectively decrease Aβ42. We have previously reported that many acidic steroids are GSMs with potencies ranging in the low to mid micromolar concentration with 5β-cholanic acid being the most potent steroid identified GSM with half maximal effective concentration (EC50) of 5.7 μM. RESULTS We find that the endogenous cholesterol metabolite, 3β-hydroxy-5-cholestenoic acid (CA), is a steroid GSM with enhanced potency (EC50 of 250 nM) relative to 5β-cholanic acid. CA i) is found in human plasma at ~100-300 nM concentrations ii) has the typical acidic GSM signature of decreasing Aβ42 and increasing Aβ38 levels iii) is active in in vitro γ-secretase assay iv) is made in the brain. To test if CA acts as an endogenous GSM, we used Cyp27a1 knockout (Cyp27a1-/-) and Cyp7b1 knockout (Cyp7b1-/-) mice to investigate if manipulation of cholesterol metabolism pathways relevant to CA formation would affect brain Aβ42 levels. Our data show that Cyp27a1-/- had increased brain Aβ42, whereas Cyp7b1-/- mice had decreased brain Aβ42 levels; however, peripheral dosing of up to 100 mg/kg CA did not affect brain Aβ levels. Structure-activity relationship (SAR) studies with multiple known and novel CA analogs studies failed to reveal CA analogs with increased potency. CONCLUSION These data suggest that CA may act as an endogenous GSM within the brain. Although it is conceptually attractive to try and increase the levels of CA in the brain for prevention of AD, our data suggest that this will not be easily accomplished.
Collapse
Affiliation(s)
- Joo In Jung
- Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, FL, 32610, USA.
- Department of Neuroscience, University of Florida, Gainesville, FL, 32610, USA.
- McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, FL, 32610, USA.
| | - Ashleigh R Price
- Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, FL, 32610, USA.
- Department of Neuroscience, University of Florida, Gainesville, FL, 32610, USA.
- McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, FL, 32610, USA.
| | - Thomas B Ladd
- Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, FL, 32610, USA.
- Department of Neuroscience, University of Florida, Gainesville, FL, 32610, USA.
- McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, FL, 32610, USA.
| | - Yong Ran
- Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, FL, 32610, USA.
- Department of Neuroscience, University of Florida, Gainesville, FL, 32610, USA.
- McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, FL, 32610, USA.
| | - Hyo-Jin Park
- Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, FL, 32610, USA.
- Department of Neuroscience, University of Florida, Gainesville, FL, 32610, USA.
- McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, FL, 32610, USA.
| | - Carolina Ceballos-Diaz
- Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, FL, 32610, USA.
- Department of Neuroscience, University of Florida, Gainesville, FL, 32610, USA.
- McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, FL, 32610, USA.
| | - Lisa A Smithson
- Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, FL, 32610, USA.
- Department of Neuroscience, University of Florida, Gainesville, FL, 32610, USA.
- McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, FL, 32610, USA.
| | - Günther Hochhaus
- College of Pharmacy, University of Florida, Gainesville, FL, 32610, USA.
| | - Yufei Tang
- College of Pharmacy, University of Florida, Gainesville, FL, 32610, USA.
| | | | - Saritha Ba
- SAI Life Sciences Ltd., Turkapally, AP500078, India.
| | - Edward H Koo
- Department of Neuroscience, University of California, La Jolla, San Diego, CA, 92093, USA.
- Departments of Medicine and Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 119077, Singapore.
| | | | - Kevin M Felsenstein
- Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, FL, 32610, USA.
- Department of Neuroscience, University of Florida, Gainesville, FL, 32610, USA.
- McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, FL, 32610, USA.
| | - Todd E Golde
- Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, FL, 32610, USA.
- Department of Neuroscience, University of Florida, Gainesville, FL, 32610, USA.
- McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, FL, 32610, USA.
| |
Collapse
|
13
|
Jung JI, Premraj S, Cruz PE, Ladd TB, Kwak Y, Koo EH, Felsenstein KM, Golde TE, Ran Y. Independent relationship between amyloid precursor protein (APP) dimerization and γ-secretase processivity. PLoS One 2014; 9:e111553. [PMID: 25350374 PMCID: PMC4211736 DOI: 10.1371/journal.pone.0111553] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Accepted: 09/28/2014] [Indexed: 12/26/2022] Open
Abstract
Altered production of β-amyloid (Aβ) from the amyloid precursor protein (APP) is closely associated with Alzheimer's disease (AD). APP has a number of homo- and hetero-dimerizing domains, and studies have suggested that dimerization of β-secretase derived APP carboxyl terminal fragment (CTFβ, C99) impairs processive cleavage by γ-secretase increasing production of long Aβs (e.g., Aβ1-42, 43). Other studies report that APP CTFβ dimers are not γ-secretase substrates. We revisited this issue due to observations made with an artificial APP mutant referred to as 3xK-APP, which contains three lysine residues at the border of the APP ectodomain and transmembrane domain (TMD). This mutant, which dramatically increases production of long Aβ, was found to form SDS-stable APP dimers, once again suggesting a mechanistic link between dimerization and increased production of long Aβ. To further evaluate how multimerization of substrate affects both initial γ-secretase cleavage and subsequent processivity, we generated recombinant wild type- (WT) and 3xK-C100 substrates, isolated monomeric, dimeric and trimeric forms of these proteins, and evaluated both ε-cleavage site utilization and Aβ production. These show that multimerization significantly impedes γ-secretase cleavage, irrespective of substrate sequence. Further, the monomeric form of the 3xK-C100 mutant increased long Aβ production without altering the initial ε-cleavage utilization. These data confirm and extend previous studies showing that dimeric substrates are not efficient γ-secretase substrates, and demonstrate that primary sequence determinants within APP substrate alter γ-secretase processivity.
Collapse
Affiliation(s)
- Joo In Jung
- Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, Florida, United States of America
- Department of Neuroscience, University of Florida, Gainesville, Florida, United States of America
- McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, Florida, United States of America
| | - Sasha Premraj
- Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, Florida, United States of America
- College of Pharmacy, University of Florida, Gainesville, Florida, United States of America
| | - Pedro E. Cruz
- Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, Florida, United States of America
- Department of Neuroscience, University of Florida, Gainesville, Florida, United States of America
- McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, Florida, United States of America
| | - Thomas B. Ladd
- Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, Florida, United States of America
- Department of Neuroscience, University of Florida, Gainesville, Florida, United States of America
- McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, Florida, United States of America
| | - Yewon Kwak
- Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, Florida, United States of America
| | - Edward H. Koo
- Department of Neuroscience, University of California San Diego, La Jolla, California, United States of America
| | - Kevin M. Felsenstein
- Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, Florida, United States of America
- Department of Neuroscience, University of Florida, Gainesville, Florida, United States of America
- McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, Florida, United States of America
| | - Todd E. Golde
- Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, Florida, United States of America
- Department of Neuroscience, University of Florida, Gainesville, Florida, United States of America
- McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, Florida, United States of America
| | - Yong Ran
- Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, Florida, United States of America
- Department of Neuroscience, University of Florida, Gainesville, Florida, United States of America
- McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, Florida, United States of America
| |
Collapse
|
14
|
Jung JI, Ran Y, Cruz PE, Rosario AM, Ladd TB, Kukar TL, Koo EH, Felsenstein KM, Golde TE. Complex relationships between substrate sequence and sensitivity to alterations in γ-secretase processivity induced by γ-secretase modulators. Biochemistry 2014; 53:1947-57. [PMID: 24620716 PMCID: PMC3985764 DOI: 10.1021/bi401521t] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
![]()
γ-Secretase
catalyzes the final cleavage of the amyloid precursor
protein (APP), resulting in the production of amyloid-β (Aβ)
peptides with different carboxyl termini. Presenilin (PSEN) and amyloid precursor protein (APP) mutations
linked to early onset familial Alzheimer’s disease modify the
profile of Aβ isoforms generated, by altering both the initial
γ-secretase cleavage site and subsequent processivity in a manner
that leads to increased levels of the more amyloidogenic Aβ42
and in some circumstances Aβ43. Compounds termed γ-secretase
modulators (GSMs) and inverse GSMs (iGSMs) can decrease and increase
levels of Aβ42, respectively. As GSMs lower the level of production
of pathogenic forms of long Aβ isoforms, they are of great interest
as potential Alzheimer’s disease therapeutics. The factors
that regulate GSM modulation are not fully understood; however, there
is a growing body of evidence that supports the hypothesis that GSM
activity is influenced by the amino acid sequence of the γ-secretase
substrate. We have evaluated whether mutations near the luminal border
of the transmembrane domain (TMD) of APP alter the ability of both
acidic, nonsteroidal anti-inflammatory drug-derived carboxylate and
nonacidic,
phenylimidazole-derived classes of GSMs and iGSMs to modulate γ-secretase
cleavage. Our data show that point mutations can dramatically reduce
the sensitivity to modulation of cleavage by GSMs but have weaker
effects on iGSM activity. These studies support the concept that the
effect of GSMs may be substrate selective; for APP, it is dependent
on the amino acid sequence of the substrate near the junction of the
extracellular domain and luminal segment of the TMD.
Collapse
Affiliation(s)
- Joo In Jung
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, and McKnight Brain Institute, College of Medicine, University of Florida , Gainesville, Florida 32603, United States
| | | | | | | | | | | | | | | | | |
Collapse
|
15
|
Ran Y, Cruz PE, Ladd TB, Fauq AH, Jung JI, Matthews J, Felsenstein KM, Golde TE. γ-Secretase processing and effects of γ-secretase inhibitors and modulators on long Aβ peptides in cells. J Biol Chem 2013; 289:3276-87. [PMID: 24352661 DOI: 10.1074/jbc.m113.512921] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Understanding how different species of Aβ are generated by γ-secretase cleavage has broad therapeutic implications, because shifts in γ-secretase processing that increase the relative production of Aβx-42/43 can initiate a pathological cascade, resulting in Alzheimer disease. We have explored the sequential stepwise γ-secretase cleavage model in cells. Eighteen BRI2-Aβ fusion protein expression constructs designed to generate peptides from Aβ1-38 to Aβ1-55 and C99 (CTFβ) were transfected into cells, and Aβ production was assessed. Secreted and cell-associated Aβ were detected using ELISA and immunoprecipitation MALDI-TOF mass spectrometry. Aβ peptides from 1-38 to 1-55 were readily detected in the cells and as soluble full-length Aβ proteins in the media. Aβ peptides longer than Aβ1-48 were efficiently cleaved by γ-secretase and produced varying ratios of Aβ1-40:Aβ1-42. γ-Secretase cleavage of Aβ1-51 resulted in much higher levels of Aβ1-42 than any other long Aβ peptides, but the processing of Aβ1-51 was heterogeneous with significant amounts of shorter Aβs, including Aβ1-40, produced. Two PSEN1 variants altered Aβ1-42 production from Aβ1-51 but not Aβ1-49. Unexpectedly, long Aβ peptide substrates such as Aβ1-49 showed reduced sensitivity to inhibition by γ-secretase inhibitors. In contrast, long Aβ substrates showed little differential sensitivity to multiple γ-secretase modulators. Although these studies further support the sequential γ-secretase cleavage model, they confirm that in cells the initial γ-secretase cleavage does not precisely define subsequent product lines. These studies also raise interesting issues about the solubility and detection of long Aβ, as well as the use of truncated substrates for assessing relative potency of γ-secretase inhibitors.
Collapse
Affiliation(s)
- Yong Ran
- From the Department of Neuroscience, Center for Translational Research in Neurodegenerative Disease and McKnight Brain Institute, College of Medicine University of Florida, Gainesville, Florida 32610 and
| | | | | | | | | | | | | | | |
Collapse
|
16
|
Jung JI, Ladd TB, Kukar T, Price AR, Moore BD, Koo EH, Golde TE, Felsenstein KM. Steroids as γ-secretase modulators. FASEB J 2013; 27:3775-85. [PMID: 23716494 PMCID: PMC3752532 DOI: 10.1096/fj.12-225649] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2013] [Accepted: 05/14/2013] [Indexed: 11/11/2022]
Abstract
Aggregation and accumulation of Aβ42 play an initiating role in Alzheimer's disease (AD); thus, selective lowering of Aβ42 by γ-secretase modulators (GSMs) remains a promising approach to AD therapy. Based on evidence suggesting that steroids may influence Aβ production, we screened 170 steroids at 10 μM for effects on Aβ42 secreted from human APP-overexpressing Chinese hamster ovary cells. Many acidic steroids lowered Aβ42, whereas many nonacidic steroids actually raised Aβ42. Studies on the more potent compounds showed that Aβ42-lowering steroids were bonafide GSMs and Aβ42-raising steroids were inverse GSMs. The most potent steroid GSM identified was 5β-cholanic acid (EC50=5.7 μM; its endogenous analog lithocholic acid was virtually equipotent), and the most potent inverse GSM identified was 4-androsten-3-one-17β-carboxylic acid ethyl ester (EC50=6.25 μM). In addition, we found that both estrogen and progesterone are weak inverse GSMs with further complex effects on APP processing. These data suggest that certain endogenous steroids may have the potential to act as GSMs and add to the evidence that cholesterol, cholesterol metabolites, and other steroids may play a role in modulating Aβ production and thus risk for AD. They also indicate that acidic steroids might serve as potential therapeutic leads for drug optimization/development.
Collapse
Affiliation(s)
- Joo In Jung
- Center for Translational Research in Neurodegenerative Disease and
- Department of Neuroscience, College of Medicine, University of Florida, Gainesville, Florida, USA
| | - Thomas B. Ladd
- Center for Translational Research in Neurodegenerative Disease and
- Department of Neuroscience, College of Medicine, University of Florida, Gainesville, Florida, USA
| | - Thomas Kukar
- Department of Pharmacology and Neurology, Emory University School of Medicine, Atlanta, Georgia, USA; and
| | - Ashleigh R. Price
- Center for Translational Research in Neurodegenerative Disease and
- Department of Neuroscience, College of Medicine, University of Florida, Gainesville, Florida, USA
| | - Brenda D. Moore
- Center for Translational Research in Neurodegenerative Disease and
- Department of Neuroscience, College of Medicine, University of Florida, Gainesville, Florida, USA
| | - Edward H. Koo
- Department of Neuroscience, University of California, San Diego, La Jolla, California, USA
| | - Todd E. Golde
- Center for Translational Research in Neurodegenerative Disease and
- Department of Neuroscience, College of Medicine, University of Florida, Gainesville, Florida, USA
| | - Kevin M. Felsenstein
- Center for Translational Research in Neurodegenerative Disease and
- Department of Neuroscience, College of Medicine, University of Florida, Gainesville, Florida, USA
| |
Collapse
|
17
|
Liu Y, Zhang W, Li L, Salvador LA, Chen T, Chen W, Felsenstein KM, Ladd TB, Price AR, Golde TE, He J, Xu Y, Li Y, Luesch H. Cyanobacterial Peptides as a Prototype for the Design of Potent β-Secretase Inhibitors and the Development of Selective Chemical Probes for Other Aspartic Proteases. J Med Chem 2012. [DOI: 10.1021/jm301630s] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Yanxia Liu
- Department of Medicinal Chemistry, University of Florida, Gainesville, Florida 32610,
United States
| | - Wei Zhang
- Department of Medicinal Chemistry, University of Florida, Gainesville, Florida 32610,
United States
- School of
Pharmacy, Fudan University, Shanghai 201203,
China
| | - Li Li
- Drug Discovery and
Design Center, Shanghai Institute of Materia Medica, Chinese Academy
of Sciences, 555 Zuchongzhi Road, Shanghai 201203, China
| | - Lilibeth A. Salvador
- Department of Medicinal Chemistry, University of Florida, Gainesville, Florida 32610,
United States
| | - Tiantian Chen
- Drug Discovery and
Design Center, Shanghai Institute of Materia Medica, Chinese Academy
of Sciences, 555 Zuchongzhi Road, Shanghai 201203, China
| | - Wuyan Chen
- Drug Discovery and
Design Center, Shanghai Institute of Materia Medica, Chinese Academy
of Sciences, 555 Zuchongzhi Road, Shanghai 201203, China
| | - Kevin M. Felsenstein
- Department of Neuroscience,
Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, Florida 32610,
United States
| | - Thomas B. Ladd
- Department of Neuroscience,
Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, Florida 32610,
United States
| | - Ashleigh R. Price
- Department of Neuroscience,
Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, Florida 32610,
United States
| | - Todd E. Golde
- Department of Neuroscience,
Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, Florida 32610,
United States
| | - Jianhua He
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai
201800, China
| | - Yechun Xu
- Drug Discovery and
Design Center, Shanghai Institute of Materia Medica, Chinese Academy
of Sciences, 555 Zuchongzhi Road, Shanghai 201203, China
| | - Yingxia Li
- School of
Pharmacy, Fudan University, Shanghai 201203,
China
| | - Hendrik Luesch
- Department of Medicinal Chemistry, University of Florida, Gainesville, Florida 32610,
United States
| |
Collapse
|
18
|
Park HJ, Shabashvili D, Nekorchuk MD, Shyqyriu E, Jung JI, Ladd TB, Moore BD, Felsenstein KM, Golde TE, Kim SH. Retention in endoplasmic reticulum 1 (RER1) modulates amyloid-β (Aβ) production by altering trafficking of γ-secretase and amyloid precursor protein (APP). J Biol Chem 2012; 287:40629-40. [PMID: 23043097 PMCID: PMC3504776 DOI: 10.1074/jbc.m112.418442] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2012] [Revised: 10/05/2012] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND Aβ production is influenced by intracellular trafficking of secretases and amyloid precursor protein (APP). RESULTS Retention in endoplasmic reticulum 1 (RER1) regulates the trafficking of γ-secretase and APP, thereby influences Aβ production. CONCLUSION RER1, an ER retention/retrieval factor for γ-secretase and APP, modulates Aβ production. SIGNIFICANCE RER1 and its influence on γ-secretase and APP may be implicated for a safe strategy to target Aβ production. The presence of neuritic plaques containing aggregated amyloid-β (Aβ) peptides in the brain parenchyma is a pathological hallmark of Alzheimer disease (AD). Aβ is generated by sequential cleavage of the amyloid β precursor protein (APP) by β- and γ-secretase, respectively. As APP processing to Aβ requires transport through the secretory pathway, trafficking of the substrate and access to the secretases are key factors that can influence Aβ production (Thinakaran, G., and Koo, E. H. (2008) Amyloid precursor protein trafficking, processing, and function. J. Biol. Chem. 283, 29615-29619). Here, we report that retention in endoplasmic reticulum 1 (RER1) associates with γ-secretase in early secretory compartments and regulates the intracellular trafficking of γ-secretase. RER1 overexpression decreases both γ-secretase localization on the cell surface and Aβ secretion and conversely RER1 knockdown increases the level of cell surface γ-secretase and increases Aβ secretion. Furthermore, we find that increased RER1 levels decrease mature APP and increase immature APP, resulting in less surface accumulation of APP. These data show that RER1 influences the trafficking and localization of both γ-secretase and APP, thereby regulating the production and secretion of Aβ peptides.
Collapse
Affiliation(s)
- Hyo-Jin Park
- From the Department of Pharmacology and Therapeutics, and
- the Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, Florida 32610
| | | | | | - Eva Shyqyriu
- From the Department of Pharmacology and Therapeutics, and
| | - Joo In Jung
- the Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, Florida 32610
| | - Thomas B. Ladd
- the Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, Florida 32610
| | - Brenda D. Moore
- the Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, Florida 32610
| | - Kevin M. Felsenstein
- the Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, Florida 32610
| | - Todd E. Golde
- the Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, Florida 32610
| | - Seong-Hun Kim
- From the Department of Pharmacology and Therapeutics, and
| |
Collapse
|
19
|
Moore BD, Chakrabarty P, Levites Y, Kukar TL, Baine AM, Moroni T, Ladd TB, Das P, Dickson DW, Golde TE. Overlapping profiles of Aβ peptides in the Alzheimer's disease and pathological aging brains. Alzheimers Res Ther 2012; 4:18. [PMID: 22621179 PMCID: PMC3506932 DOI: 10.1186/alzrt121] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/08/2012] [Revised: 04/17/2012] [Accepted: 05/23/2012] [Indexed: 12/11/2022]
Abstract
INTRODUCTION A hallmark of Alzheimer's disease (AD) is the presence of senile plaques composed of aggregated amyloid β (Aβ) peptides. Pathological aging (PA) is a postmortem classification that has been used to describe brains with plaque pathology similar in extent to AD, minimal cortical tau pathology, and no accompanying history of cognitive decline in the brain donor prior to death. PA may represent either a prodromal phase of AD, a benign form of Aβ accumulation, or inherent individual resistance to the toxic effects of Aβ accumulation. To attempt to distinguish between these possibilities we have systematically characterized Aβ peptides in a postmortem series of PA, AD and non-demented control (NDC) brains. METHODS Aβ was sequentially extracted with tris buffered saline (TBS), radioimmunoprecipitation buffer (RIPA), 2% sodium dodecyl sulfate (SDS) and 70% formic acid (FA) from the pre-frontal cortex of 16 AD, eight PA, and six NDC patients. These extracts were analyzed by 1) a panel of Aβ sandwich ELISAs, 2) immunoprecipitation followed by mass spectrometry (IP/MS) and 3) western blotting. These studies enabled us to asses Aβ levels and solubility, peptide profiles and oligomeric assemblies. RESULTS In almost all extracts (TBS, RIPA, 2% SDS and 70% FA) the average levels of Aβ1-40, Aβ1-42, Aβ total, and Aβx-42 were greatest in AD. On average, levels were slightly lower in PA, and there was extensive overlap between Aβ levels in individual PA and AD cases. The profiles of Aβ peptides detected using IP/MS techniques also showed extensive similarity between the PA and AD brain extracts. In select AD brain extracts, we detected more amino-terminally truncated Aβ peptides compared to PA patients, but these peptides represented a minor portion of the Aβ observed. No consistent differences in the Aβ assemblies were observed by western blotting in the PA and AD groups. CONCLUSIONS We found extensive overlap with only subtle quantitative differences between Aβ levels, peptide profiles, solubility, and SDS-stable oligomeric assemblies in the PA and AD brains. These cross-sectional data indicate that Aβ accumulation in PA and AD is remarkably similar. Such data would be consistent with PA representing a prodromal stage of AD or a resistance to the toxic effects of Aβ.
Collapse
Affiliation(s)
- Brenda D Moore
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, McKnight Brain Institute, College of Medicine, University of Florida, 1275 Center Drive, Gainesville, FL, 32610, USA.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Kukar TL, Ladd TB, Robertson P, Pintchovski SA, Moore B, Bann MA, Ren Z, Jansen-West K, Malphrus K, Eggert S, Maruyama H, Cottrell BA, Das P, Basi GS, Koo EH, Golde TE. Lysine 624 of the amyloid precursor protein (APP) is a critical determinant of amyloid β peptide length: support for a sequential model of γ-secretase intramembrane proteolysis and regulation by the amyloid β precursor protein (APP) juxtamembrane region. J Biol Chem 2011; 286:39804-12. [PMID: 21868378 PMCID: PMC3220543 DOI: 10.1074/jbc.m111.274696] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Revised: 08/16/2011] [Indexed: 11/06/2022] Open
Abstract
γ-Secretase is a multiprotein intramembrane cleaving aspartyl protease (I-CLiP) that catalyzes the final cleavage of the amyloid β precursor protein (APP) to release the amyloid β peptide (Aβ). Aβ is the primary component of senile plaques in Alzheimer's disease (AD), and its mechanism of production has been studied intensely. γ-Secretase executes multiple cleavages within the transmembrane domain of APP, with cleavages producing Aβ and the APP intracellular domain (AICD), referred to as γ and ε, respectively. The heterogeneous nature of the γ cleavage that produces various Aβ peptides is highly relevant to AD, as increased production of Aβ 1-42 is genetically and biochemically linked to the development of AD. We have identified an amino acid in the juxtamembrane region of APP, lysine 624, on the basis of APP695 numbering (position 28 relative to Aβ) that plays a critical role in determining the final length of Aβ peptides released by γ-secretase. Mutation of this lysine to alanine (K28A) shifts the primary site of γ-secretase cleavage from 1-40 to 1-33 without significant changes to ε cleavage. These results further support a model where ε cleavage occurs first, followed by sequential proteolysis of the remaining transmembrane fragment, but extend these observations by demonstrating that charged residues at the luminal boundary of the APP transmembrane domain limit processivity of γ-secretase.
Collapse
Affiliation(s)
- Thomas L Kukar
- Emory University, School of Medicine, Department of Pharmacology, Center for Neurodegenerative Disease, Atlanta, Georgia 30322, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
21
|
Czirr E, Cottrell BA, Leuchtenberger S, Kukar T, Ladd TB, Esselmann H, Paul S, Schubenel R, Torpey JW, Pietrzik CU, Golde TE, Wiltfang J, Baumann K, Koo EH, Weggen S. Independent Generation of Aβ42 and Aβ38 Peptide Species by γ-Secretase. J Biol Chem 2008; 283:17049-54. [DOI: 10.1074/jbc.m802912200] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
|
22
|
Nyborg AC, Herl L, Berezovska O, Thomas AV, Ladd TB, Jansen K, Hyman BT, Golde TE. Signal peptide peptidase (SPP) dimer formation as assessed by fluorescence lifetime imaging microscopy (FLIM) in intact cells. Mol Neurodegener 2006; 1:16. [PMID: 17105660 PMCID: PMC1654158 DOI: 10.1186/1750-1326-1-16] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2006] [Accepted: 11/14/2006] [Indexed: 11/13/2022] Open
Abstract
Background Signal peptide peptidase (SPP) is an intramembrane cleaving protease identified by its cleavage of several type II membrane signal peptides. Conservation of intramembrane active site residues demonstrates that SPP, SPP family members, and presenilins (PSs) make up a family of intramembrane cleaving proteases. Because SPP appears to function without additional protein cofactors, the study of SPP may provide structural insights into the mechanism of intramembrane proteolysis by this biomedically important family of proteins. Previous studies have shown that SPP isolated from cells appears to be a homodimer, but some evidence exists that in vitro SPP may be active as a monomer. We have conducted additional experiments to determine if SPP exists as a monomer or dimer in vivo. Results Fluorescence lifetime imaging microscopy (FLIM) can be is used to determine intra- or intermolecular interactions by fluorescently labeling epitopes on one or two different molecules. If the donor and acceptor fluorophores are less than 10 nm apart, the donor fluorophore lifetime shortens proportionally to the distance between the fluorophores. In this study, we used two types of fluorescence energy transfer (FRET) pairs; cyan fluorescent protein (CFP) with yellow fluorescent protein (YFP) or Alexa 488 with Cy3 to differentially label the NH2- or COOH-termini of SPP molecules. A cell based SPP activity assay was used to show that all tagged SPP proteins are proteolytically active. Using FLIM we were able to show that the donor fluorophore lifetime of the CFP tagged SPP construct in living cells significantly decreases when either a NH2- or COOH-terminally YFP tagged SPP construct is co-transfected, indicating close proximity between two different SPP molecules. These data were then confirmed in cell lines stably co-expressing V5- and FLAG-tagged SPP constructs. Conclusion Our FLIM data strongly suggest dimer formation between two separate SPP proteins. Although the tagged SPP constructs are expressed throughout the cell, SPP dimer detection by FLIM is seen predominantly at or near the plasma membrane.
Collapse
Affiliation(s)
- Andrew C Nyborg
- Department of Neuroscience, Mayo Clinic Jacksonville, Mayo Clinic College of Medicine, Jacksonville, Florida 32224, USA
| | - Lauren Herl
- Alzheimer's Disease Research Unit, Massachusetts Institute for Neurodegenerative Diseases, Massachusetts General Hospital, Charlestown, Massachusetts 02129, USA
| | - Oksana Berezovska
- Alzheimer's Disease Research Unit, Massachusetts Institute for Neurodegenerative Diseases, Massachusetts General Hospital, Charlestown, Massachusetts 02129, USA
| | - Anne V Thomas
- Alzheimer's Disease Research Unit, Massachusetts Institute for Neurodegenerative Diseases, Massachusetts General Hospital, Charlestown, Massachusetts 02129, USA
| | - Thomas B Ladd
- Department of Neuroscience, Mayo Clinic Jacksonville, Mayo Clinic College of Medicine, Jacksonville, Florida 32224, USA
| | - Karen Jansen
- Department of Neuroscience, Mayo Clinic Jacksonville, Mayo Clinic College of Medicine, Jacksonville, Florida 32224, USA
| | - Bradley T Hyman
- Alzheimer's Disease Research Unit, Massachusetts Institute for Neurodegenerative Diseases, Massachusetts General Hospital, Charlestown, Massachusetts 02129, USA
| | - Todd E Golde
- Department of Neuroscience, Mayo Clinic Jacksonville, Mayo Clinic College of Medicine, Jacksonville, Florida 32224, USA
| |
Collapse
|
23
|
Nyborg AC, Ladd TB, Jansen K, Kukar T, Golde TE. Intramembrane proteolytic cleavage by human signal peptide peptidase like 3 and malaria signal peptide peptidase. FASEB J 2006; 20:1671-9. [PMID: 16873890 DOI: 10.1096/fj.06-5762com] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Signal peptide peptidase (SPP) is an intramembrane cleaving protease (I-CLiP) identified by its cleavage of several type II membrane signal peptides. To date, only human SPP has been directly shown to have proteolytic activity. Here we demonstrate that the most closely related human homologue of SPP, signal peptide peptidase like 3 (SPPL3), cleaves a SPP substrate, but a more distantly related homologue, signal peptide peptidase like 2b (SPPL2b), does not. These data provide strong evidence that the SPP and SPPL3 have conserved active sites and suggest that the active sites SPPL2b is distinct. We have also synthesized a cDNA designed to express the single SPP gene present in Plasmodium falciparum and cloned this into a mammalian expression vector. When the malaria SPP protein is expressed in mammalian cells it cleaves a SPP substrate. Notably, several human SPP inhibitors block the proteolytic activity of malarial SPP (mSPP). Studies from several model organisms that express multiple SPP homologs demonstrate that the silencing of a single SPP homologue is lethal. Based on these data, we hypothesize that mSPP is a potential a novel therapeutic target for malaria.
Collapse
Affiliation(s)
- Andrew C Nyborg
- Department of Neuroscience, Mayo Clinic Jacksonville, Mayo Clinic College of Medicine, 4500 San Pablo Rd., Jacksonville, Florida 32224, USA
| | | | | | | | | |
Collapse
|
24
|
Nyborg AC, Levites Y, Ladd TB, Zwizinski CW, Jansen K, Golde TE. O3–03–03: Sortilin, SorLA, SorCS1: Just novel gamma–secretase substrates or more intimately involved in AD pathogenesis? Alzheimers Dement 2006. [DOI: 10.1016/j.jalz.2006.05.207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
|
25
|
Nyborg AC, Ladd TB, Zwizinski CW, Lah JJ, Golde TE. Sortilin, SorCS1b, and SorLA Vps10p sorting receptors, are novel gamma-secretase substrates. Mol Neurodegener 2006; 1:3. [PMID: 16930450 PMCID: PMC1513133 DOI: 10.1186/1750-1326-1-3] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2006] [Accepted: 06/12/2006] [Indexed: 11/30/2022] Open
Abstract
Background The mammalian Vps10p sorting receptor family is a group of 5 type I membrane homologs (Sortilin, SorLA, and SorCS1-3). These receptors bind various cargo proteins via their luminal Vps10p domains and have been shown to mediate a variety of intracellular sorting and trafficking functions. These proteins are highly expressed in the brain. SorLA has been shown to be down regulated in Alzheimer's disease brains, interact with ApoE, and modulate Aβ production. Sortilin has been shown to be part of proNGF mediated death signaling that results from a complex of Sortilin, p75NTR and proNGF. We have investigated and provide evidence for γ-secretase cleavage of this family of proteins. Results We provide evidence that these receptors are substrates for presenilin dependent γ-secretase cleavage. γ-Secretase cleavage of these sorting receptors is inhibited by γ-secretase inhibitors and does not occur in PS1/PS2 knockout cells. Like most γ-secretase substrates, we find that ectodomain shedding precedes γ-secretase cleavage. The ectodomain cleavage is inhibited by a metalloprotease inhibitor and activated by PMA suggesting that it is mediated by an α-secretase like cleavage. Conclusion These data indicate that the α- and γ-secretase cleavages of the mammalian Vps10p sorting receptors occur in a fashion analogous to other known γ-secretase substrates, and could possibly regulate the biological functions of these proteins.
Collapse
Affiliation(s)
- Andrew C Nyborg
- Department of Neuroscience, Mayo Clinic Jacksonville, Mayo Clinic College of Medicine, 4500 San Pablo Road, Jacksonville, Florida 32224, USA
| | - Thomas B Ladd
- Department of Neuroscience, Mayo Clinic Jacksonville, Mayo Clinic College of Medicine, 4500 San Pablo Road, Jacksonville, Florida 32224, USA
| | - Craig W Zwizinski
- Department of Neuroscience, Mayo Clinic Jacksonville, Mayo Clinic College of Medicine, 4500 San Pablo Road, Jacksonville, Florida 32224, USA
| | - James J Lah
- Department of Neurology, Center for Neurodegenerative Disease, Emory University, Whitehead Biomedical Research Building, 615 Michael Street, Suite 505, Atlanta, GA 30322, USA
| | - Todd E Golde
- Department of Neuroscience, Mayo Clinic Jacksonville, Mayo Clinic College of Medicine, 4500 San Pablo Road, Jacksonville, Florida 32224, USA
| |
Collapse
|
26
|
Leuchtenberger S, Kummer MP, Kukar T, Czirr E, Teusch N, Sagi SA, Berdeaux R, Pietrzik CU, Ladd TB, Golde TE, Koo EH, Weggen S. Inhibitors of Rho-kinase modulate amyloid-β (Aβ) secretion but lack selectivity for Aβ42. J Neurochem 2006; 96:355-65. [PMID: 16300630 DOI: 10.1111/j.1471-4159.2005.03553.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Certain non-steroidal anti-inflammatory drugs (NSAIDs) preferentially inhibit production of the amyloidogenic Abeta42 peptide, presumably by direct modulation of gamma-secretase activity. A recent report indicated that NSAIDs could reduce Abeta42 by inhibition of the small GTPase Rho, and a single inhibitor of Rho kinase (ROCK) mimicked the effects of Abeta42-lowering NSAIDs. To investigate whether Abeta42 reduction is a common property of ROCK inhibitors, we tested commercially available compounds in cell lines that were previously used to demonstrate the Abeta42-lowering activity of NSAIDs. Surprisingly, we found that two ROCK inhibitors reduced total Abeta secretion in a dose-dependent manner but showed no selectivity for Abeta42. In addition, ROCK inhibitors did not increase Abeta38 secretion in cell-based assays or reduce Abeta production in gamma-secretase in vitro assays, which are critical characteristics of Abeta42-lowering NSAIDs. The reduction in total Abeta levels by ROCK inhibitors was not accompanied by overall-changes in amyloid precursor protein processing. Targeting ROCK by expression of dominant-negative or constitutively active ROCK mutants failed to modulate Abeta secretion, indicating that ROCK inhibition may either be redundant or insufficient for Abeta reduction by ROCK inhibitors. Taken together, these results seem to exclude a mechanistic involvement of ROCK in the Abeta42-lowering activity of NSAIDs.
Collapse
Affiliation(s)
- Stefanie Leuchtenberger
- Emmy Noether Research Group, Institute of Physiological Chemistry and Pathobiochemistry, Johannes Gutenberg University Mainz, Mainz, Germany
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
27
|
Nyborg AC, Jansen K, Ladd TB, Fauq A, Golde TE. A signal peptide peptidase (SPP) reporter activity assay based on the cleavage of type II membrane protein substrates provides further evidence for an inverted orientation of the SPP active site relative to presenilin. J Biol Chem 2004; 279:43148-56. [PMID: 15252014 DOI: 10.1074/jbc.m405879200] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Signal peptide peptidase (SPP) is an intramembrane-cleaving protease identified by its cleavage of several type II membrane signal peptides after signal peptidase cleavage. Here we describe a novel, quantitative, cell-based SPP reporter assay. This assay utilizes a substrate consisting of the NH2 terminus of the ATF6 transcription factor fused to a transmembrane domain susceptible to SPP cleavage in vitro. In cells, cleavage of the substrate releases ATF6 from the membrane. This cleavage can be monitored by detection of an epitope that is unmasked in the cleaved substrate or by luciferase activity induced by the cleaved ATF6 substrate binding to and activating an ATF6 luciferase reporter construct. Using this assay we show that (i) SPP is the first aspartyl intramembrane-cleaving protease whose activity increases proportionally to its overexpression and (ii) selectivity of various SPP and gamma-secretase inhibitors can be rapidly evaluated. Because this assay was designed based on data suggesting that SPP has an orientation distinct from presenilin and cleaves type II membrane proteins, we determined whether the segment of SPP located between the two presumptive catalytic aspartates was in the lumen or cytoplasm. Using site-directed mutagenesis to insert an N-linked glycosylation site we show that a portion of this region is present in the lumen. These data provide strong evidence that although the SPP and presenilin active sites have some similarities, their presumptive catalytic domains are inverted. This assay should prove useful for additional functional studies of SPP as well as evaluation of SPP and gamma-secretase inhibitors.
Collapse
Affiliation(s)
- Andrew C Nyborg
- Mayo Clinic, Mayo Clinic College of Medicine, Department of Neuroscience, Jacksonville, Florida 32224, USA
| | | | | | | | | |
Collapse
|
28
|
Nyborg AC, Ladd TB, Jansen K, Kornilova A, Wolfe MS, Golde TE. P4-276 Presenilin homolog, signal peptide peptidase, provides a basis for understanding intramembrane aspartic proteolytic cleavage. Neurobiol Aging 2004. [DOI: 10.1016/s0197-4580(04)81834-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
29
|
Nyborg AC, Kornilova AY, Jansen K, Ladd TB, Wolfe MS, Golde TE. Signal peptide peptidase forms a homodimer that is labeled by an active site-directed gamma-secretase inhibitor. J Biol Chem 2004; 279:15153-60. [PMID: 14704149 DOI: 10.1074/jbc.m309305200] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Presenilin (PS) is the presumptive catalytic component of the intramembrane aspartyl protease gamma-secretase complex. Recently a family of presenilin homologs was identified. One member of this family, signal peptide peptidase (SPP), has been shown to be a protease, which supports the hypothesis that PS and presenilin homologs are related intramembrane-cleaving aspartyl proteases. SPP has been reported as a glycoprotein of approximately 45 kDa. Our initial characterization of SPP isolated from human brain and cell lines demonstrated that SPP is primarily present as an SDS-stable approximately 95-kDa protein on Western blots. Upon heating or treatment of this approximately 95-kDa SPP band with acid, a approximately 45-kDa band could be resolved. Co-purification of two different epitope-tagged forms of SPP from a stably transfected cell line expressing both tagged versions demonstrated that the approximately 95-kDa band is a homodimer of SPP. Pulse-chase metabolic labeling studies demonstrated that the SPP homodimer assembles rapidly and is metabolically stable. In a glycerol velocity gradient, SPP sedimented from approximately 100-200 kDa. Significantly the SPP homodimer was specifically labeled by an active site-directed photoaffinity probe (III-63) for PS, indicating that the active sites of SPP and PS/gamma-secretase are similar and providing strong evidence that the homodimer is functionally active. Collectively these data suggest that SPP exists in vivo as a functional dimer.
Collapse
Affiliation(s)
- Andrew C Nyborg
- Department of Neuroscience, Mayo Clinic Jacksonville, Jacksonville, Florida 32224, USA
| | | | | | | | | | | |
Collapse
|