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Kropf E, Shekari A, Jaberi S, Puri A, Wu C, Fahnestock M. Age-induced nitrative stress decreases retrograde transport of proNGF via TrkA and increases proNGF retrograde transport and neurodegeneration via p75 NTR. Front Mol Neurosci 2023; 16:1241420. [PMID: 38025269 PMCID: PMC10679388 DOI: 10.3389/fnmol.2023.1241420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Accepted: 10/18/2023] [Indexed: 12/01/2023] Open
Abstract
Introduction Axonal transport of pro nerve growth factor (proNGF) is impaired in aged basal forebrain cholinergic neurons (BFCNs), which is associated with their degeneration. ProNGF is neurotrophic in the presence of its receptor tropomyosin-related kinase A (TrkA) but induces apoptosis via the pan-neurotrophin receptor (p75NTR) when TrkA is absent. It is well established that TrkA is lost while p75NTR is maintained in aged BFCNs, but whether aging differentially affects transport of proNGF via each receptor is unknown. Nitrative stress increases during aging, but whether age-induced nitrative stress differentially affects proNGF transport via TrkA versus p75NTR has not yet been studied. Answering these questions is essential for developing an accurate understanding of the mechanisms contributing to age-induced loss of proNGF transport and BFCN degeneration. Methods In this study, fluorescence microscopy was used to analyze axonal transport of quantum dot labeled proNGF in rat BFCNs in vitro. Receptor specific effects were studied with proNGF mutants that selectively bind to either TrkA (proNGF-KKE) or p75NTR (proNGF-Δ9-13). Signaling factor activity was quantified via immunostaining. Results Young BFCNs transported proNGF-KKE but not proNGF-Δ9-13, and proNGF transport was not different in p75NTR knockout BFCNs compared to wildtype BFCNs. These results indicate that young BFCNs transport proNGF via TrkA. In vitro aging increased transport of proNGF-Δ9-13 but decreased transport of proNGF-KKE. Treatment with the nitric oxide synthase inhibitor L-NAME reduced retrograde transport of proNGF-Δ9-13 in aged BFCNs while increasing retrograde transport of proNGF-KKE but did not affect TrkA or p75NTR levels. ProNGF-Δ9-13 induced greater pro-apoptotic signaling and neurodegeneration and less pro-survival signaling relative to proNGF-KKE. Discussion Together, these results indicate that age-induced nitrative stress decreases proNGF transport via TrkA while increasing proNGF transport via p75NTR. These transport deficits are associated with decreased survival signaling, increased apoptotic signaling, and neurodegeneration. Our findings elucidate the receptor specificity of age-and nitrative stress-induced proNGF transport deficits. These results may help to rescue the neurotrophic signaling of proNGF in aging to reduce age-induced loss of BFCN function and cognitive decline.
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Affiliation(s)
- Erika Kropf
- Neuroscience Program, McMaster University, Hamilton, ON, Canada
| | - Arman Shekari
- Neuroscience Program, McMaster University, Hamilton, ON, Canada
| | - Sama Jaberi
- Neuroscience Program, McMaster University, Hamilton, ON, Canada
| | - Anish Puri
- Neuroscience Program, McMaster University, Hamilton, ON, Canada
| | - Chengbiao Wu
- Department of Neurosciences, University of California San Diego, La Jolla, CA, United States
| | - Margaret Fahnestock
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, ON, Canada
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2
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Schirripa Spagnolo C, Luin S. Setting up multicolour TIRF microscopy down to the single molecule level. Biomol Concepts 2023; 14:bmc-2022-0032. [PMID: 37428621 DOI: 10.1515/bmc-2022-0032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Accepted: 06/26/2023] [Indexed: 07/12/2023] Open
Abstract
Investigating biological mechanisms in ever greater detail requires continuous advances in microscopy techniques and setups. Total internal reflection fluorescence (TIRF) microscopy is a well-established technique for visualizing processes on the cell membrane. TIRF allows studies down to the single molecule level, mainly in single-colour applications. Instead, multicolour setups are still limited. Here, we describe our strategies for implementing a multi-channel TIRF microscopy system capable of simultaneous two-channel excitation and detection, starting from a single-colour commercial setup. First, we report some applications at high molecule density and then focus on the challenges we faced for achieving the single molecule level simultaneously in different channels, showing that rigorous optimizations on the setup are needed to increase its sensitivity up to this point, from camera setting to background minimization. We also discuss our strategies regarding crucial points of fluorescent labelling for this type of experiment: labelling strategy, kind of probe, efficiency, and orthogonality of the reaction, all of which are aspects that can influence the achievable results. This work may provide useful guidelines for setting up advanced single-molecule multi-channel TIRF experiments to obtain insights into interaction mechanisms on the cell membrane of living cells.
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Affiliation(s)
| | - Stefano Luin
- NEST Laboratory, Scuola Normale Superiore, Piazza San Silvestro 12, I-56127, Pisa, Italy
- NEST Laboratory, Istituto Nanoscienze-Consiglio Nazionale delle ricerche (CNR), Piazza San Silvestro 12, I-56127, Pisa, Italy
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3
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Falconieri A, De Vincentiis S, Cappello V, Convertino D, Das R, Ghignoli S, Figoli S, Luin S, Català-Castro F, Marchetti L, Borello U, Krieg M, Raffa V. Axonal plasticity in response to active forces generated through magnetic nano-pulling. Cell Rep 2022; 42:111912. [PMID: 36640304 PMCID: PMC9902337 DOI: 10.1016/j.celrep.2022.111912] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 11/16/2022] [Accepted: 12/12/2022] [Indexed: 12/30/2022] Open
Abstract
Mechanical force is crucial in guiding axon outgrowth before and after synapse formation. This process is referred to as "stretch growth." However, how neurons transduce mechanical input into signaling pathways remains poorly understood. Another open question is how stretch growth is coupled in time with the intercalated addition of new mass along the entire axon. Here, we demonstrate that active mechanical force generated by magnetic nano-pulling induces remodeling of the axonal cytoskeleton. Specifically, the increase in the axonal density of microtubules induced by nano-pulling leads to an accumulation of organelles and signaling vesicles, which, in turn, promotes local translation by increasing the probability of assembly of the "translation factories." Modulation of axonal transport and local translation sustains enhanced axon outgrowth and synapse maturation.
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Affiliation(s)
| | - Sara De Vincentiis
- Department of Biology, Università di Pisa, 56127 Pisa, Italy,The Barcelona Institute of Science and Technology, Institut de Ciències Fotòniques, ICFO, 08860 Castelldefels, Spain
| | - Valentina Cappello
- Center for Materials Interfaces, Istituto Italiano di Tecnologia, 56025 Pontedera, Italy
| | - Domenica Convertino
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia, 56127 Pisa, Italy
| | - Ravi Das
- The Barcelona Institute of Science and Technology, Institut de Ciències Fotòniques, ICFO, 08860 Castelldefels, Spain
| | | | - Sofia Figoli
- Department of Biology, Università di Pisa, 56127 Pisa, Italy
| | - Stefano Luin
- National Enterprise for NanoScience and NanoTechnology (NEST) Laboratory, Scuola Normale Superiore, 56127 Pisa, Italy
| | - Frederic Català-Castro
- The Barcelona Institute of Science and Technology, Institut de Ciències Fotòniques, ICFO, 08860 Castelldefels, Spain
| | - Laura Marchetti
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia, 56127 Pisa, Italy,Department of Pharmacy, Università di Pisa, 56126 Pisa, Italy
| | - Ugo Borello
- Department of Biology, Università di Pisa, 56127 Pisa, Italy
| | - Michael Krieg
- The Barcelona Institute of Science and Technology, Institut de Ciències Fotòniques, ICFO, 08860 Castelldefels, Spain
| | - Vittoria Raffa
- Department of Biology, Università di Pisa, 56127 Pisa, Italy.
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4
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Marcelić M, Lučin HM, Begonja AJ, Zagorac GB, Lisnić VJ, Lučin P. Endosomal Phosphatidylinositol-3-Phosphate-Associated Functions Are Dispensable for Establishment of the Cytomegalovirus Pre-Assembly Compartment but Essential for the Virus Growth. Life (Basel) 2021; 11:859. [PMID: 34440603 PMCID: PMC8398575 DOI: 10.3390/life11080859] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 08/16/2021] [Accepted: 08/20/2021] [Indexed: 01/20/2023] Open
Abstract
Murine cytomegalovirus (MCMV) initiates the stepwise establishment of the pre-assembly compartment (pre-AC) in the early phase of infection by the expansion of the early endosome (EE)/endosomal recycling compartment (ERC) interface and relocation of the Golgi complex. We depleted Vps34-derived phosphatidylinositol-3-phosphate (PI(3)P) at EEs by VPS34-IN1 and inhibited PI(3)P-associated functions by overexpression of 2xFYVE- and p40PX PI(3)P-binding modules to assess the role of PI(3)P-dependent EE domains in the pre-AC biogenesis. We monitored the accumulation of Rab10 and Evectin-2 in the inner pre-AC and the relocation of GM130-positive cis-Golgi organelles to the outer pre-AC by confocal microscopy. Although PI(3)P- and Vps34-positive endosomes build a substantial part of pre-AC, the PI(3)P depletion and the inhibition of PI(3)P-associated functions did not prevent the establishment of infection and progression through the early phase. The PI(3)P depletion in uninfected and MCMV-infected cells rapidly dispersed PI(3)P-bond proteins and reorganized EEs, including ablation of EE-to-ERC transport and relocation of Rab11 endosomes. The PI(3)P depletion one hour before pre-AC initiation and overexpression of 2xFYVE and p40PX domains neither prevented Rab10- and Evectin-2 accumulation, nor Golgi unlinking and relocation. These data demonstrate that PI(3)P-dependent functions, including the Rab11-dependent EE-to-ERC route, are dispensable for pre-AC initiation. Nevertheless, the virus growth was drastically reduced in PI(3)P-depleted cells, indicating that PI(3)P-associated functions are essential for the late phase of infection.
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Affiliation(s)
- Marina Marcelić
- Department of Physiology and Immunology, Faculty of Medicine, University of Rijeka, 51000 Rijeka, Croatia; (M.M.); (H.M.L.); (G.B.Z.)
| | - Hana Mahmutefendić Lučin
- Department of Physiology and Immunology, Faculty of Medicine, University of Rijeka, 51000 Rijeka, Croatia; (M.M.); (H.M.L.); (G.B.Z.)
- University North, University Center Varaždin, Jurja Križanića 31b, 42000 Varaždin, Croatia
| | - Antonija Jurak Begonja
- Department of Biotechnology, University of Rijeka, Radmile Matejčić 2, 51000 Rijeka, Croatia;
| | - Gordana Blagojević Zagorac
- Department of Physiology and Immunology, Faculty of Medicine, University of Rijeka, 51000 Rijeka, Croatia; (M.M.); (H.M.L.); (G.B.Z.)
- University North, University Center Varaždin, Jurja Križanića 31b, 42000 Varaždin, Croatia
| | - Vanda Juranić Lisnić
- Center for Proteomics, Department of Histology and Embryology, Faculty of Medicine, University of Rijeka, 51000 Rijeka, Croatia;
| | - Pero Lučin
- Department of Physiology and Immunology, Faculty of Medicine, University of Rijeka, 51000 Rijeka, Croatia; (M.M.); (H.M.L.); (G.B.Z.)
- University North, University Center Varaždin, Jurja Križanića 31b, 42000 Varaždin, Croatia
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5
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Kropf E, Fahnestock M. Effects of Reactive Oxygen and Nitrogen Species on TrkA Expression and Signalling: Implications for proNGF in Aging and Alzheimer's Disease. Cells 2021; 10:cells10081983. [PMID: 34440751 PMCID: PMC8392605 DOI: 10.3390/cells10081983] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 07/30/2021] [Accepted: 08/02/2021] [Indexed: 11/18/2022] Open
Abstract
Nerve growth factor (NGF) and its precursor form, proNGF, are critical for neuronal survival and cognitive function. In the brain, proNGF is the only detectable form of NGF. Dysregulation of proNGF in the brain is implicated in age-related memory loss and Alzheimer’s disease (AD). AD is characterized by early and progressive degeneration of the basal forebrain, an area critical for learning, memory, and attention. Learning and memory deficits in AD are associated with loss of proNGF survival signalling and impaired retrograde transport of proNGF to the basal forebrain. ProNGF transport and signalling may be impaired by the increased reactive oxygen and nitrogen species (ROS/RNS) observed in the aged and AD brain. The current literature suggests that ROS/RNS nitrate proNGF and reduce the expression of the proNGF receptor tropomyosin-related kinase A (TrkA), disrupting its downstream survival signalling. ROS/RNS-induced reductions in TrkA expression reduce cell viability, as proNGF loses its neurotrophic function in the absence of TrkA and instead generates apoptotic signalling via the pan-neurotrophin receptor p75NTR. ROS/RNS also interfere with kinesin and dynein motor functions, causing transport deficits. ROS/RNS-induced deficits in microtubule motor function and TrkA expression and signalling may contribute to the vulnerability of the basal forebrain in AD. Antioxidant treatments may be beneficial in restoring proNGF signalling and axonal transport and reducing basal forebrain neurodegeneration and related deficits in cognitive function.
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Affiliation(s)
- Erika Kropf
- Graduate Program in Neuroscience, Faculty of Health Sciences, McMaster University, Hamilton, ON L8S 4K1, Canada;
| | - Margaret Fahnestock
- Department of Psychiatry and Behavioural Neurosciences, Faculty of Health Sciences, McMaster University, Hamilton, ON L8S 4K1, Canada
- Correspondence:
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6
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Convertino D, Mishra N, Marchetti L, Calvello M, Viegi A, Cattaneo A, Fabbri F, Coletti C. Effect of Chemical Vapor Deposition WS 2 on Viability and Differentiation of SH-SY5Y Cells. Front Neurosci 2020; 14:592502. [PMID: 33192279 PMCID: PMC7662391 DOI: 10.3389/fnins.2020.592502] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 10/07/2020] [Indexed: 01/09/2023] Open
Abstract
In recent years, transition metal dichalcogenides have been attracting an increasing interest in the biomedical field, thus implying the need of a deeper understanding of their impact on cell behavior. In this study we investigate tungsten disulfide (WS2) grown via chemical vapor deposition (CVD) on a transparent substrate (sapphire) as a platform for neural-like cell culture. We culture SH-SY5Y human neuroblastoma cells on WS2, using graphene, sapphire and standard culture well as controls. The quality, thickness and homogeneity of the materials is analyzed using atomic force microscopy and Raman spectroscopy. The cytocompatibility of CVD WS2 is investigated for the first time by cell viability and differentiation assessment on SH-SY5Y cells. We find that cells differentiated on WS2, displaying a viability and neurite length comparable with the controls. These findings shine light on the possibility of using WS2 as a cytocompatible material for interfacing neural cells.
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Affiliation(s)
- Domenica Convertino
- National Enterprise for nanoScience and nanoTechnology Laboratory, Scuola Normale Superiore, Pisa, Italy
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia, Pisa, Italy
| | - Neeraj Mishra
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia, Pisa, Italy
| | - Laura Marchetti
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia, Pisa, Italy
- Department of Pharmacy, University of Pisa, Pisa, Italy
| | | | | | | | - Filippo Fabbri
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia, Pisa, Italy
- NEST Istituto Nanoscienze—CNR and Scuola Normale Superiore, Pisa, Italy
| | - Camilla Coletti
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia, Pisa, Italy
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7
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Amodeo R, Convertino D, Calvello M, Ceccarelli L, Bonsignore F, Ravelli C, Cattaneo A, Martini C, Luin S, Mitola S, Signore G, Marchetti L. Fluorolabeling of the PPTase-Related Chemical Tags: Comparative Study of Different Membrane Receptors and Different Fluorophores in the Labeling Reactions. Front Mol Biosci 2020; 7:195. [PMID: 32850976 PMCID: PMC7426934 DOI: 10.3389/fmolb.2020.00195] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 07/22/2020] [Indexed: 11/13/2022] Open
Abstract
The set-up of an advanced imaging experiment requires a careful selection of suitable labeling strategies and fluorophores for the tagging of the molecules of interest. Here we provide an experimental workflow to allow evaluation of fluorolabeling performance of the chemical tags target of phosphopantetheinyl transferase enzymes (PPTases), once inserted in the sequence of different proteins of interest. First, S6 peptide tag was fused to three different single-pass transmembrane proteins (the tyrosine receptor kinases TrkA and VEGFR2 and the tumor necrosis factor receptor p75NTR), providing evidence that all of them can be conveniently albeit differently labeled. Moreover, we chose the S6-tagged TrkA construct to test eight different organic fluorophores for the PPTase labeling of membrane receptors in living cells. We systematically compared their non-specific internalization when added to a S6-tag negative cell culture, the percentage of S6-TrkA expressing cells effectively labeled and the relative mean fluorescence intensity, their photostability upon conjugation, and ratio of specific (cellular) versus background (glass-adhered) signal. This allowed to identify which fluorophores are actually recommended for these labeling reactions. Finally, we compared the PPTase labeling of a purified, YBBR-tagged Nerve Growth Factor with two differently charged organic dyes. We detected some batch-to-batch variability in the labeling yield, regardless of the fluorophore used. However, upon purification of the fluorescent species and incubation with living primary DRG neurons, no significant difference could be appreciated in both internalization and axonal transport of the labeled neurotrophins.
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Affiliation(s)
- Rosy Amodeo
- NEST, Scuola Normale Superiore, Pisa, Italy.,Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia, Pisa, Italy
| | - Domenica Convertino
- NEST, Scuola Normale Superiore, Pisa, Italy.,Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia, Pisa, Italy
| | | | - Lorenzo Ceccarelli
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia, Pisa, Italy.,Dipartimento di Farmacia, Università di Pisa, Pisa, Italy
| | | | - Cosetta Ravelli
- Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
| | | | | | - Stefano Luin
- NEST, Scuola Normale Superiore, Pisa, Italy.,CNR-NANO, Pisa, Italy
| | - Stefania Mitola
- Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
| | - Giovanni Signore
- NEST, Scuola Normale Superiore, Pisa, Italy.,Fondazione Pisana per la Scienza Onlus, Pisa, Italy
| | - Laura Marchetti
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia, Pisa, Italy.,Dipartimento di Farmacia, Università di Pisa, Pisa, Italy
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8
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Convertino D, Fabbri F, Mishra N, Mainardi M, Cappello V, Testa G, Capsoni S, Albertazzi L, Luin S, Marchetti L, Coletti C. Graphene Promotes Axon Elongation through Local Stall of Nerve Growth Factor Signaling Endosomes. NANO LETTERS 2020; 20:3633-3641. [PMID: 32208704 DOI: 10.1021/acs.nanolett.0c00571] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Several works reported increased differentiation of neuronal cells grown on graphene; however, the molecular mechanism driving axon elongation on this material has remained elusive. Here, we study the axonal transport of nerve growth factor (NGF), the neurotrophin supporting development of peripheral neurons, as a key player in the time course of axonal elongation of dorsal root ganglion neurons on graphene. We find that graphene drastically reduces the number of retrogradely transported NGF vesicles in favor of a stalled population in the first 2 days of culture, in which the boost of axon elongation is observed. This correlates with a mutual charge redistribution, observed via Raman spectroscopy and electrophysiological recordings. Furthermore, ultrastructural analysis indicates a reduced microtubule distance and an elongated axonal topology. Thus, both electrophysiological and structural effects can account for graphene action on neuron development. Unraveling the molecular players underneath this interplay may open new avenues for axon regeneration applications.
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Affiliation(s)
- Domenica Convertino
- NEST, Scuola Normale Superiore, 56127 Pisa, Italy
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia, 56127 Pisa, Italy
| | - Filippo Fabbri
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia, 56127 Pisa, Italy
| | - Neeraj Mishra
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia, 56127 Pisa, Italy
| | - Marco Mainardi
- BIO@SNS Laboratory, Scuola Normale Superiore, 56126 Pisa, Italy
| | - Valentina Cappello
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia, 56127 Pisa, Italy
| | - Giovanna Testa
- BIO@SNS Laboratory, Scuola Normale Superiore, 56126 Pisa, Italy
| | - Simona Capsoni
- BIO@SNS Laboratory, Scuola Normale Superiore, 56126 Pisa, Italy
- Section of Physiology, Department of Biomedical and Specialty Surgical Sciences, University of Ferrara, via Borsari 46, 44121 Ferrara, Italy
| | - Lorenzo Albertazzi
- Nanoscopy for Nanomedicine Group, Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology (BIST), Carrer Baldiri Reixac 15-21, 08024 Barcelona, Spain
- Department of Biomedical Engineering, Institute for Complex Molecular Systems (ICMS), Eindhoven University of Technology, 5612AZ Eindhoven, The Netherlands
| | - Stefano Luin
- NEST, Scuola Normale Superiore, 56127 Pisa, Italy
- NEST Istituto Nanoscienze, CNR and Scuola Normale Superiore, 56126 Pisa, Italy
| | - Laura Marchetti
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia, 56127 Pisa, Italy
- Department of Pharmacy, University of Pisa, 56127 Pisa, Italy
| | - Camilla Coletti
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia, 56127 Pisa, Italy
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9
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Fahnestock M, Shekari A. ProNGF and Neurodegeneration in Alzheimer's Disease. Front Neurosci 2019; 13:129. [PMID: 30853882 PMCID: PMC6395390 DOI: 10.3389/fnins.2019.00129] [Citation(s) in RCA: 76] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 02/05/2019] [Indexed: 11/13/2022] Open
Abstract
Profound and early basal forebrain cholinergic neuron (BFCN) degeneration is a hallmark of Alzheimer's disease (AD). Loss of synapses between basal forebrain and hippocampal and cortical target tissue correlates highly with the degree of dementia and is thought to be a major contributor to memory loss. BFCNs depend for their survival, connectivity and function on the neurotrophin nerve growth factor (NGF) which is retrogradely transported from its sites of synthesis in the cortex and hippocampus. The form of NGF found in human brain is proNGF. ProNGF binds to the NGF receptors TrkA and p75NTR, but it binds more strongly to p75NTR and more weakly to TrkA than does mature NGF. This renders proNGF more sensitive to receptor balance than mature NGF. In the healthy brain, where BFCNs express both TrkA and p75NTR, proNGF is neurotrophic, activating TrkA-dependent signaling pathways such as MAPK and Akt-mTOR and eliciting cell survival and neurite outgrowth. However, if TrkA is lost or if p75NTR is increased, proNGF activates p75NTR-dependent apoptotic pathways such as JNK. This receptor sensitivity serves as a neurotrophic/apoptotic switch that eliminates BFCNs that cannot maintain TrkA/p75NTR balance and therefore synaptic connections with their targets. TrkA is increasingly lost in mild cognitive impairment (MCI) and AD. In addition, proNGF accumulates at BFCN terminals in cortex and hippocampus, reducing the amount of trophic factor that reaches BFCN cell bodies. The loss of TrkA and accumulation of proNGF occur early in MCI and correlate with cognitive impairment. Increased levels of proNGF and reduced levels of TrkA lead to BFCN neurodegeneration and eventual p75NTR-dependent apoptosis. In addition, in AD BFCNs suffer from reduced TrkA-dependent retrograde transport which reduces neurotrophic support. Thus, BFCNs are particularly vulnerable to AD due to their dependence upon retrograde trophic support from proNGF signaling and transport.
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Affiliation(s)
- Margaret Fahnestock
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, ON, Canada
| | - Arman Shekari
- Neuroscience Graduate Program, McMaster University, Hamilton, ON, Canada
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10
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Gobbo F, Bonsignore F, Amodeo R, Cattaneo A, Marchetti L. Site-Specific Direct Labeling of Neurotrophins and Their Receptors: From Biochemistry to Advanced Imaging Applications. Methods Mol Biol 2018; 1727:295-314. [PMID: 29222790 DOI: 10.1007/978-1-4939-7571-6_22] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We describe here a versatile methodological platform to achieve site-directed and stoichiometry-controlled labeling of neurotrophins and their receptors with various probes, ranging from biotin to small organic dyes. This labeling method works in vitro on purified neurotrophins as well as in a living cell context, where it achieves selective labeling of surface-exposed neurotrophin receptors. Here, we list all experimental details of our labeling protocols, along with examples of the wide range of applications in which these can be used.
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Affiliation(s)
- Francesco Gobbo
- Bio@SNS, Scuola Normale Superiore, Piazza dei Cavalieri 7, Pisa, 56126, Italy
| | - Fulvio Bonsignore
- NEST, Scuola Normale Superiore, Piazza San Silvestro 12, Pisa, 56127, Italy
| | - Rosy Amodeo
- NEST, Scuola Normale Superiore, Piazza San Silvestro 12, Pisa, 56127, Italy
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia, Piazza San Silvestro 12, Pisa, 56127, Italy
| | - Antonino Cattaneo
- Bio@SNS, Scuola Normale Superiore, Piazza dei Cavalieri 7, Pisa, 56126, Italy
| | - Laura Marchetti
- Bio@SNS, Scuola Normale Superiore, Piazza dei Cavalieri 7, Pisa, 56126, Italy.
- NEST, Scuola Normale Superiore, Piazza San Silvestro 12, Pisa, 56127, Italy.
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia, Piazza San Silvestro 12, Pisa, 56127, Italy.
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