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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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2
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Filimonova T, Karakulova Y. Tropomyosin receptor kinase B-mediated signaling in integration of neuropathic pain and obesity in diabetic polyneuropathy. EINSTEIN-SAO PAULO 2021; 19:eAO6256. [PMID: 34586159 PMCID: PMC8448548 DOI: 10.31744/einstein_journal/2021ao6256] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Accepted: 04/24/2021] [Indexed: 01/13/2023] Open
Abstract
Objective: To assess the quantitative serum levels of tropomyosin receptor kinase receptor B, and to estimate its association with serum concentration of brain-derived neurotrophic factor and obesity in patients with painful and painless forms of diabetic polyneuropathy. Methods: We examined 70 patients with diabetic polyneuropathy with confirming peripheral nerve dysfunction by electroneuromyography and measuring of serum levels tropomyosin receptor kinase receptor B and brain-derived neurotrophic factor by enzyme immunoassay. Diabetic polyneuropathy was diagnosed using the modified Toronto Consensus (2011) criteria, while neuropathic pain was assessed using an 11-point Numerical Pain Rating Scale. The patients were divided into two groups according to presence or absence of neuropathic pain. Control Group consisted of 14 healthy persons. Results: The serum levels of tropomyosin receptor kinase receptor B and brain-derived neurotrophic factor in patients with diabetic polyneuropathy are significantly higher than healthy controls (p=0.000). Hyperexpression of brain-derived neurotrophic factor in serum was associated with painful form of diabetic polyneuropathy (R=0.392, p=0.012) and obesity (R=0.412, p=0.001). On the contrary high concentration of tropomyosin receptor kinase receptor B in serum associated with painless diabetic polyneuropathy by Pain DETECT (R=-0.354, p=0.015), low body weight (R=-0.354, p=0.015) and severe demyelization of nerve fibers (R=-0.574, p=0.001), indicated “non-working” receptor detected in serum. Conclusion: Tropomyosin receptor kinase receptor B signaling is involved in the modulation of neuropathic pain and obesity in diabetic polyneuropathy.
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3
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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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4
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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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5
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Durso W, Martins M, Marchetti L, Cremisi F, Luin S, Cardarelli F. Lysosome Dynamic Properties during Neuronal Stem Cell Differentiation Studied by Spatiotemporal Fluctuation Spectroscopy and Organelle Tracking. Int J Mol Sci 2020; 21:ijms21093397. [PMID: 32403391 PMCID: PMC7247004 DOI: 10.3390/ijms21093397] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 05/08/2020] [Accepted: 05/09/2020] [Indexed: 01/20/2023] Open
Abstract
We investigated lysosome dynamics during neuronal stem cell (NSC) differentiation by two quantitative and complementary biophysical methods based on fluorescence: imaging-derived mean square displacement (iMSD) and single-particle tracking (SPT). The former extracts the average dynamics and size of the whole population of moving lysosomes directly from imaging, with no need to calculate single trajectories; the latter resolves the finest heterogeneities and dynamic features at the single-lysosome level, which are lost in the iMSD analysis. In brief, iMSD analysis reveals that, from a structural point of view, lysosomes decrement in size during NSC differentiation, from 1 μm average diameter in the embryonic cells to approximately 500 nm diameter in the fully differentiated cells. Concomitantly, iMSD analysis highlights modification of key dynamic parameters, such as the average local organelle diffusivity and anomalous coefficient, which may parallel cytoskeleton remodeling during the differentiation process. From average to local, SPT allows mapping heterogeneous dynamic responses of single lysosomes in different districts of the cells. For instance, a dramatic decrease of lysosomal transport in the soma is followed by a rapid increase of transport in the projections at specific time points during neuronal differentiation, an observation compatible with the hypothesis that lysosomal active mobilization shifts from the soma to the newborn projections. Our combined results provide new insight into the lysosome size and dynamics regulation throughout NSC differentiation, supporting new functions proposed for this organelle.
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Affiliation(s)
- William Durso
- NEST Laboratory—Scuola Normale Superiore, Piazza San Silvestro 12, 56127 Pisa, Italy;
| | - Manuella Martins
- Bio@SNS Laboratory—Scuola Normale Superiore, via G. Moruzzi, 1, 56126 Pisa, Italy; (M.M.); (F.C.)
| | - Laura Marchetti
- Center for Nanotechnology Innovation@NEST (CNI@NEST), Piazza San Silvestro 12, 56126 Pisa, Italy;
| | - Federico Cremisi
- Bio@SNS Laboratory—Scuola Normale Superiore, via G. Moruzzi, 1, 56126 Pisa, Italy; (M.M.); (F.C.)
| | - Stefano Luin
- NEST Laboratory—Scuola Normale Superiore, Piazza San Silvestro 12, 56127 Pisa, Italy;
- NEST, Istituto Nanoscienze, CNR, Piazza San Silvestro 12, 56127 Pisa, Italy
- Correspondence: (S.L.); (F.C.)
| | - Francesco Cardarelli
- NEST Laboratory—Scuola Normale Superiore, Piazza San Silvestro 12, 56127 Pisa, Italy;
- Correspondence: (S.L.); (F.C.)
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6
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Amodeo R, Nifosì R, Giacomelli C, Ravelli C, La Rosa L, Callegari A, Trincavelli ML, Mitola S, Luin S, Marchetti L. Molecular insight on the altered membrane trafficking of TrkA kinase dead mutants. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2019; 1867:118614. [PMID: 31760089 DOI: 10.1016/j.bbamcr.2019.118614] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 11/11/2019] [Accepted: 11/18/2019] [Indexed: 12/18/2022]
Abstract
We address the contribution of kinase domain structure and catalytic activity to membrane trafficking of TrkA receptor tyrosine kinase. We conduct a systematic comparison between TrkA-wt, an ATP-binding defective mutant (TrkA-K544N) and other mutants displaying separate functional impairments of phosphorylation, ubiquitination, or recruitment of intracellular partners. We find that only K544N mutation endows TrkA with restricted membrane mobility and a substantial increase of cell surface pool already in the absence of ligand stimulation. This mutation is predicted to drive a structural destabilization of the αC helix in the N-lobe by molecular dynamics simulations, and enhances interactions with elements of the actin cytoskeleton. On the other hand, a different TrkA membrane immobilization is selectively observed after NGF stimulation, requires both phosphorylation and ubiquitination to occur, and is most probably related to the signaling abilities displayed by the wt but not mutated receptors. In conclusion, our results allow to distinguish two different TrkA membrane immobilization modes and demonstrate that not all kinase-inactive mutants display identical membrane trafficking.
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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.
| | - Riccardo Nifosì
- NEST, Scuola Normale Superiore, Pisa, Italy; NEST, Istituto Nanoscienze-CNR, Pisa, Italy
| | | | - Cosetta Ravelli
- Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
| | | | | | | | - Stefania Mitola
- Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
| | - Stefano Luin
- NEST, Scuola Normale Superiore, Pisa, Italy; NEST, Istituto Nanoscienze-CNR, Pisa, Italy
| | - Laura Marchetti
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia, Pisa, Italy; Department of Pharmacy, University of Pisa, Pisa, Italy.
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7
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Liu Z, Cao Y, Liu G, Yin S, Ma J, Liu J, Zhang M, Wang Y. p75 neurotrophin receptor regulates NGF-induced myofibroblast differentiation and collagen synthesis through MRTF-A. Exp Cell Res 2019; 383:111504. [PMID: 31325438 DOI: 10.1016/j.yexcr.2019.111504] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 07/02/2019] [Accepted: 07/15/2019] [Indexed: 02/09/2023]
Abstract
Myofibroblasts are characterized by de novo expression of α-smooth muscle actin (α-SMA) and play a key role in tissue repair and remodeling. In addition to TGF-β1, recent studies have shown that nerve growth factor (NGF) has effects on myofibroblast differentiation and collagen synthesis. However, the regulatory mechanism remains poorly defined. NGF effects are mediated by the specific expression of the NGF neurotrophic tropomyosin-receptor kinase A (TrkA) and p75 neurotrophin receptor (p75NTR). Using NIH/3T3 fibroblast cell lines, we examined the induction of myofibroblast differentiation stimulated by NGF. Our findings showed that p75NTR was in keeping with the expression of α-SMA. Herein, we investigated the role of p75NTR in NGF-induced myofibroblast differentiation and collagen synthesis in these cells using lentivirus transfection to overexpress and knock down. Our results showed that p75NTR was preferentially expressed and was sufficient to induce actin cytoskeleton remodeling, which was required for NGF-induced α-SMA expression. Furthermore, NGF induced nuclear translocation of MRTF-A, an effect that was regulated by p75NTR, and required for α-SMA and collagen-I expression in myofibroblasts. Using a novel MRTF-A pathway inhibitor, CCG-203971, we further demonstrated the requirement of MRTF-A nuclear localization and activity in NGF-induced α-SMA expression. In conclusion, we conclude that p75NTR regulates NGF-induced myofibroblast differentiation and collagen synthesis through MRTF-A. Regulation of NGF-p75NTR interactions represents a promising therapy for fibrotic disorders.
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Affiliation(s)
- Zhenxing Liu
- Department of Oral and Maxillofacial Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, 250021, China
| | - Yongqian Cao
- Department of Burns and Plastic Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, 250021, Shandong, China
| | - Guijun Liu
- Department of Oral and Maxillofacial Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, 250021, China
| | - Siyuan Yin
- Department of Burns and Plastic Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, 250021, Shandong, China
| | - Jiaxu Ma
- Department of Burns and Plastic Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, 250021, Shandong, China
| | - Jian Liu
- Department of Burns and Plastic Surgery, Yantai Yuhuangding Hospital, Yantai, 264000, Shandong, China
| | - Min Zhang
- Department of Burns and Plastic Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, 250021, Shandong, China
| | - Yibing Wang
- Department of Burns and Plastic Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, 250021, Shandong, China.
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8
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Barabás K, Godó S, Lengyel F, Ernszt D, Pál J, Ábrahám IM. Rapid non-classical effects of steroids on the membrane receptor dynamics and downstream signaling in neurons. Horm Behav 2018; 104:183-191. [PMID: 29775570 DOI: 10.1016/j.yhbeh.2018.05.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 05/08/2018] [Accepted: 05/09/2018] [Indexed: 12/26/2022]
Abstract
Contribution to Special Issue on Fast effects of steroids. Although rapid effects of steroid hormones on membrane receptors and intracellular signaling molecules have been extensively studied in neurons, we are only beginning to understand the molecular mechanisms behind these non-classical steroid actions. Single molecule tracking (SMT) studies on live cells demonstrated that surface trafficking of membrane receptors determines their ligand binding properties and downstream signaling events. Recent findings suggest that one of the underlying mechanisms of non-classical steroid actions is the alteration of receptor movements on the membrane surface. In order to highlight this novel aspect of steroid effects, we first address the types of receptor movements in the plasma membrane and the role of cortical actin dynamics in receptor movement. We then discuss how single molecules and the surface movements of receptors can be detected in live cells. Next, we review the fundamental processes, which determine the effect of steroids on the plasma membrane: steroid movement through the lipid bilayer and the role of steroid membrane receptors. Using glutamate and neurotrophin receptors (NTRs) as examples, we demonstrate the features of receptor dynamics in the membrane. In addition, we survey the available data of rapid steroid actions on membrane receptor trafficking: we discuss how glucocorticoids act on the surface diffusion of glutamate receptor molecules and how estradiol acts on NTRs and gamma-aminobutyric acid type A receptors (GABAARs) and their related signaling events as well as on cortical actin. Finally, we address the physiological relevance of rapid steroid action on membrane receptors dynamics.
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Affiliation(s)
- Klaudia Barabás
- MTA NAP-B Molecular Neuroendocrinology Research Group, Institute of Physiology, Medical School, Centre for Neuroscience, Szentágothai Research Institute, University of Pécs, Pécs, Hungary
| | - Soma Godó
- MTA NAP-B Molecular Neuroendocrinology Research Group, Institute of Physiology, Medical School, Centre for Neuroscience, Szentágothai Research Institute, University of Pécs, Pécs, Hungary
| | - Ferenc Lengyel
- MTA NAP-B Molecular Neuroendocrinology Research Group, Institute of Physiology, Medical School, Centre for Neuroscience, Szentágothai Research Institute, University of Pécs, Pécs, Hungary
| | - Dávid Ernszt
- MTA NAP-B Molecular Neuroendocrinology Research Group, Institute of Physiology, Medical School, Centre for Neuroscience, Szentágothai Research Institute, University of Pécs, Pécs, Hungary
| | - József Pál
- MTA NAP-B Molecular Neuroendocrinology Research Group, Institute of Physiology, Medical School, Centre for Neuroscience, Szentágothai Research Institute, University of Pécs, Pécs, Hungary
| | - István M Ábrahám
- MTA NAP-B Molecular Neuroendocrinology Research Group, Institute of Physiology, Medical School, Centre for Neuroscience, Szentágothai Research Institute, University of Pécs, Pécs, Hungary.
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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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10
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Angelov B, Angelova A. Nanoscale clustering of the neurotrophin receptor TrkB revealed by super-resolution STED microscopy. NANOSCALE 2017; 9:9797-9804. [PMID: 28682396 DOI: 10.1039/c7nr03454g] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The nanoscale organization of the tropomyosin-related kinase receptor type B (TrkB), a promising therapeutic target for severe neurodegenerative and psychiatric disorders, is examined by stimulated emission depletion (STED) microscopy using the deconvoluted gated STED option. The performed immunofluorescence nanoscopic subdiffraction imaging of the membrane receptor localization reveals that clusters of oligomeric TrkB states and randomly organized nanodomains are formed in the membranes of differentiated human neuroblastoma SH-SY5Y cells, which are studied as an in vitro model of neurodegeneration. Despite that the monomeric (isolated) states of the receptor cannot be distinguished from its dimeric forms in such images, TrkB receptor dimers (or couple of individual monomers) are visualized at super-resolution as single pixels in the magnified Huygens-deconvoluted gated STED images. The clusters of higher-order TrkB oligomers are of dynamic nature rather than of a fixed stoichiometry. The propensity for membrane protein clustering as well as the dissociation of the TrkB receptors nanodomains can be modulated by neurotherapeutic formulations containing ω-3 polyunsaturated docosahexaenoic acid (DHA). Nanomolar concentrations of DHA change the receptor topology and lead to disruption of the cluster phases. This result is of therapeutic importance for TrkB receptor availability upon ligand binding as DHA favours the mobility and the dynamic distribution of the protein populations in the cell membranes.
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Affiliation(s)
- Borislav Angelov
- Institute of Physics, ELI Beamlines, Academy of Sciences of the Czech Republic, Na Slovance 2, CZ-18221 Prague, Czech Republic
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11
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Pincelli C. p75 Neurotrophin Receptor in the Skin: Beyond Its Neurotrophic Function. Front Med (Lausanne) 2017; 4:22. [PMID: 28326307 PMCID: PMC5339601 DOI: 10.3389/fmed.2017.00022] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 02/16/2017] [Indexed: 12/16/2022] Open
Abstract
p75 neurotrophin receptor (p75NTR), also known as CD271, is the low-affinity receptor that, together with the tyrosine kinase receptor tropomyosin-receptor kinase (Trk), mediate neurotrophin (NT) functions. Beside their classic role in skin innervation, NT and their receptors constitute a complex cutaneous network associated with a number of autocrine and paracrine activities. In this context, the role of p75NTR is becoming more and more important. This review will focus on the intriguing functions of p75NTR in healthy and diseased skin. First, p75NTR counterbalances the proliferative and survival activities of its cognate receptor Trk by inducing keratinocyte apoptosis. In addition, p75NTR identifies an early transit-amplifying (TA) keratinocyte population and plays a critical role in keratinocyte stem cell transition to its progeny as well as in epidermal differentiation. p75NTR is absent in psoriatic TA cells, thus rendering these cells resistant to apoptosis. On the other hand, p75NTR infection restores NT-induced apoptosis in psoriatic keratinocytes. Taken together, these results provide evidence for a critical role of p75NTR in epidermal homeostasis, while its lack may account for the TA defect in psoriasis. While the issue of p75NTR as a marker of melanoma initiating cells is still to be solved, there is strong evidence that downregulation of this receptor is a precondition to melanoma invasion and metastasis in vitro and in vivo. All in all, this review points to p75NTR as a major actor in both physiologic and pathologic conditions at the skin level.
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Affiliation(s)
- Carlo Pincelli
- Laboratory of Cutaneous Biology, Department of Surgical, Medical, Dental and Morphological Sciences, University of Modena and Reggio Emilia , Modena , Italy
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Di Matteo P, Calvello M, Luin S, Marchetti L, Cattaneo A. An Optimized Procedure for the Site-Directed Labeling of NGF and proNGF for Imaging Purposes. Front Mol Biosci 2017; 4:4. [PMID: 28210618 PMCID: PMC5288393 DOI: 10.3389/fmolb.2017.00004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 01/12/2017] [Indexed: 12/12/2022] Open
Abstract
Neurotrophins are growth factors of fundamental importance for the development, survival and maintenance of different neuronal and non-neuronal populations. Over the years, the use of labeled neurotrophins has helped in the study of their biological functions, leading to a better understanding of the processes that regulate their transport, traffic, and signaling. However, the diverse and heterogeneous neurotrophin labeling strategies adopted so far have often led to poorly reproducible protocols and sometimes conflicting conclusions. Here we present a robust, reliable, and fast method to obtain homogeneous preparations of fluorescent proNGF and NGF with 1:1 labeling stoichiometry. This strategy is well suited for several applications, ranging from advanced imaging techniques such as single particle tracking, to analyses that require large amounts of neurotrophins such as in vivo monitoring of protein biodistribution. As a proof of the quality of the labeled NGF and proNGF preparations, we provide a quantitative analysis of their colocalization with proteins involved in the signaling endosome function and sorting. This new analysis allowed demonstrating that proNGF localizes at a sub-population of endosomes not completely overlapped to the one hosting NGF.
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Affiliation(s)
- Pierluigi Di Matteo
- BioSNS Laboratory, Scuola Normale Superiore and Istituto di Neuroscienze - CNR Pisa, Italy
| | | | - Stefano Luin
- NEST Laboratory, Scuola Normale Superiore and Istituto Nanoscienze - CNR Pisa, Italy
| | - Laura Marchetti
- BioSNS Laboratory, Scuola Normale Superiore and Istituto di Neuroscienze - CNRPisa, Italy; Center for Nanotechnology Innovation@NEST, Istituto Italiano di TecnologiaPisa, Italy
| | - Antonino Cattaneo
- BioSNS Laboratory, Scuola Normale Superiore and Istituto di Neuroscienze - CNR Pisa, Italy
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De Nadai T, Marchetti L, Di Rienzo C, Calvello M, Signore G, Di Matteo P, Gobbo F, Turturro S, Meucci S, Viegi A, Beltram F, Luin S, Cattaneo A. Precursor and mature NGF live tracking: one versus many at a time in the axons. Sci Rep 2016; 6:20272. [PMID: 26829890 PMCID: PMC4735336 DOI: 10.1038/srep20272] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Accepted: 10/14/2015] [Indexed: 12/11/2022] Open
Abstract
The classical view of nerve growth factor (NGF) action in the nervous system is linked to its retrograde axonal transport. However, almost nothing is known on the trafficking properties of its unprocessed precursor proNGF, characterized by different and generally opposite biological functions with respect to its mature counterpart. Here we developed a strategy to fluorolabel both purified precursor and mature neurotrophins (NTs) with a controlled stoichiometry and insertion site. Using a single particle tracking approach, we characterized the axonal transport of proNGF versus mature NGF in living dorsal root ganglion neurons grown in compartmentalized microfluidic devices. We demonstrate that proNGF is retrogradely transported as NGF, but with a lower flux and a different distribution of numbers of neurotrophins per vesicle. Moreover, exploiting a dual-color labelling technique, we analysed the transport of both NT forms when simultaneously administered to the axon tips.
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Affiliation(s)
- Teresa De Nadai
- BioSNS Laboratory, Scuola Normale Superiore and Istituto di Neuroscienze - CNR, Pisa, Italy
| | - Laura Marchetti
- BioSNS Laboratory, Scuola Normale Superiore and Istituto di Neuroscienze - CNR, Pisa, Italy.,NEST, Scuola Normale Superiore and Istituto Nanoscienze-CNR, Pisa, Italy
| | - Carmine Di Rienzo
- NEST, Scuola Normale Superiore and Istituto Nanoscienze-CNR, Pisa, Italy.,Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia, Piazza San Silvestro 12-56127 Pisa, Italy
| | | | - Giovanni Signore
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia, Piazza San Silvestro 12-56127 Pisa, Italy
| | - Pierluigi Di Matteo
- BioSNS Laboratory, Scuola Normale Superiore and Istituto di Neuroscienze - CNR, Pisa, Italy
| | - Francesco Gobbo
- BioSNS Laboratory, Scuola Normale Superiore and Istituto di Neuroscienze - CNR, Pisa, Italy
| | | | - Sandro Meucci
- NEST, Scuola Normale Superiore and Istituto Nanoscienze-CNR, Pisa, Italy.,Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia, Piazza San Silvestro 12-56127 Pisa, Italy
| | - Alessandro Viegi
- BioSNS Laboratory, Scuola Normale Superiore and Istituto di Neuroscienze - CNR, Pisa, Italy
| | - Fabio Beltram
- NEST, Scuola Normale Superiore and Istituto Nanoscienze-CNR, Pisa, Italy.,Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia, Piazza San Silvestro 12-56127 Pisa, Italy
| | - Stefano Luin
- NEST, Scuola Normale Superiore and Istituto Nanoscienze-CNR, Pisa, Italy
| | - Antonino Cattaneo
- BioSNS Laboratory, Scuola Normale Superiore and Istituto di Neuroscienze - CNR, Pisa, Italy
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