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Olivero G, Grilli M, Marchi M, Pittaluga A. Metamodulation of presynaptic NMDA receptors: New perspectives for pharmacological interventions. Neuropharmacology 2023; 234:109570. [PMID: 37146939 DOI: 10.1016/j.neuropharm.2023.109570] [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: 02/15/2023] [Revised: 04/26/2023] [Accepted: 05/02/2023] [Indexed: 05/07/2023]
Abstract
Metamodulation shifted the scenario of the central neuromodulation from a simplified unimodal model to a multimodal one. It involves different receptors/membrane proteins physically associated or merely colocalized that act in concert to control the neuronal functions influencing each other. Defects or maladaptation of metamodulation would subserve neuropsychiatric disorders or even synaptic adaptations relevant to drug dependence. Therefore, this "vulnerability" represents a main issue to be deeply analyzed to predict its aetiopathogenesis, but also to propose targeted pharmaceutical interventions. The review focusses on presynaptic release-regulating NMDA receptors and on some of the mechanisms of their metamodulation described in the literature. Attention is paid to the interactors, including both ionotropic and metabotropic receptors, transporters and intracellular proteins, which metamodulate their responsiveness in physiological conditions but also undergo adaptation that are relevant to neurological dysfunctions. All these structures are attracting more and more the interest as promising druggable targets for the treatment of NMDAR-related central diseases: these substances would not exert on-off control of the colocalized NMDA receptors (as usually observed with NMDAR full agonists/antagonists), but rather modulate their functions, with the promise of limiting side effects that would favor their translation from preclinic to clinic.
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Affiliation(s)
- Guendalina Olivero
- Department of Pharmacy, University of Genoa, Viale Cembrano 4, 16148, Genoa, Italy
| | - Massimo Grilli
- Department of Pharmacy, University of Genoa, Viale Cembrano 4, 16148, Genoa, Italy; Inter-University Center for the Promotion of the 3Rs Principles in Teaching & Research (Centro 3R), 16148, Genoa, Italy.
| | - Mario Marchi
- Department of Pharmacy, University of Genoa, Viale Cembrano 4, 16148, Genoa, Italy
| | - Anna Pittaluga
- Department of Pharmacy, University of Genoa, Viale Cembrano 4, 16148, Genoa, Italy; Inter-University Center for the Promotion of the 3Rs Principles in Teaching & Research (Centro 3R), 16148, Genoa, Italy
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Agnati LF, Guidolin D, Cervetto C, Maura G, Marcoli M. Brain Structure and Function: Insights from Chemical Neuroanatomy. Life (Basel) 2023; 13:life13040940. [PMID: 37109469 PMCID: PMC10142941 DOI: 10.3390/life13040940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 02/24/2023] [Accepted: 03/31/2023] [Indexed: 04/07/2023] Open
Abstract
We present a brief historical and epistemological outline of investigations on the brain’s structure and functions. These investigations have mainly been based on the intermingling of chemical anatomy, new techniques in the field of microscopy and computer-assisted morphometric methods. This intermingling has enabled extraordinary investigations to be carried out on brain circuits, leading to the development of a new discipline: “brain connectomics”. This new approach has led to the characterization of the brain’s structure and function in physiological and pathological conditions, and to the development of new therapeutic strategies. In this context, the conceptual model of the brain as a hyper-network with a hierarchical, nested architecture, arranged in a “Russian doll” pattern, has been proposed. Our investigations focused on the main characteristics of the modes of communication between nodes at the various miniaturization levels, in order to describe the brain’s integrative actions. Special attention was paid to the nano-level, i.e., to the allosteric interactions among G protein-coupled receptors organized in receptor mosaics, as a promising field in which to obtain a new view of synaptic plasticity and to develop new, more selective drugs. The brain’s multi-level organization and the multi-faceted aspects of communication modes point to an emerging picture of the brain as a very peculiar system, in which continuous self-organization and remodeling take place under the action of external stimuli from the environment, from peripheral organs and from ongoing integrative actions.
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Affiliation(s)
- Luigi F. Agnati
- Department of Biochemical, Metabolic Sciences and Neuroscience, University of Modena and Reggio Emilia, 41125 Modena, Italy
| | - Diego Guidolin
- Department of Neuroscience, University of Padova, 35121 Padova, Italy
| | - Chiara Cervetto
- Department of Pharmacy, University of Genova, 16148 Genova, Italy
- Center for Promotion of 3Rs in Teaching and Research (Centro 3R), 56122 Pisa, Italy
| | - Guido Maura
- Department of Pharmacy, University of Genova, 16148 Genova, Italy
| | - Manuela Marcoli
- Department of Pharmacy, University of Genova, 16148 Genova, Italy
- Center for Promotion of 3Rs in Teaching and Research (Centro 3R), 56122 Pisa, Italy
- Center of Excellence for Biomedical Research, University of Genova, 16132 Genova, Italy
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Bono F, Mutti V, Tomasoni Z, Sbrini G, Missale C, Fiorentini C. Recent Advances in Dopamine D3 Receptor Heterodimers: Focus on Dopamine D3 and D1 Receptor-Receptor Interaction and Striatal Function. Curr Top Behav Neurosci 2022; 60:47-72. [PMID: 35505059 DOI: 10.1007/7854_2022_353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
G protein-coupled receptors (GPCR) heterodimers represent new entities with unique pharmacological, signalling, and trafficking properties, with specific distribution restricted to those cells where the two interacting receptors are co-expressed. Like other GPCR, dopamine D3 receptors (D3R) directly interact with various receptors to form heterodimers: data showing the D3R physical interaction with both GPCR and non-GPCR receptors have been provided including D3R interaction with other dopamine receptors. The aim of this chapter is to summarize current knowledge of the distinct roles of heterodimers involving D3R, focusing on the D3R interaction with the dopamine D1 receptor (D1R): the D1R-D3R heteromer, in fact, has been postulated in both ventral and motor striatum. Interestingly, since both D1R and D3R have been implicated in several pathological conditions, including schizophrenia, motor dysfunctions, and substance use disorders, the D1R-D3R heteromer may represent a potential drug target for the treatment of these diseases.
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Affiliation(s)
- Federica Bono
- Division of Pharmacology, Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
| | - Veronica Mutti
- Division of Pharmacology, Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
| | - Zaira Tomasoni
- Division of Pharmacology, Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
| | - Giulia Sbrini
- Division of Pharmacology, Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
| | - Cristina Missale
- Division of Pharmacology, Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
| | - Chiara Fiorentini
- Division of Pharmacology, Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy.
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Guidolin D, Marcoli M, Tortorella C, Maura G, Agnati LF. Adenosine A 2A-dopamine D 2 receptor-receptor interaction in neurons and astrocytes: Evidence and perspectives. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2019; 169:247-277. [PMID: 31952688 DOI: 10.1016/bs.pmbts.2019.11.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The discovery of receptor-receptor interactions in the early 1980s, together with a more accurate focusing of allosteric mechanisms in proteins, expanded the knowledge on the G protein-coupled receptor (GPCR)-mediated signaling processes. GPCRs were seen to operate not only as monomers, but also as quaternary structures shaped by allosteric interactions. These integrative mechanisms can change the function of the GPCRs involved, leading to a sophisticated dynamic of the receptor assembly in terms of modulation of recognition and signaling. In this context, the heterodimeric complex formed by the adenosine A2A and the dopamine D2 receptors likely represents a prototypical example. The pharmacological evidence obtained, together with the tissue distribution of the A2A-D2 heteromeric complexes, suggested they could represent a target for new therapeutic strategies addressing significant disorders of the central nervous system. The research findings and the perspectives they offer from the therapeutic standpoint are the focus of the here presented discussion.
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Affiliation(s)
- Diego Guidolin
- Department of Neuroscience, Section of Anatomy, University of Padova, Padova, Italy.
| | - Manuela Marcoli
- Department of Pharmacy and Center of Excellence for Biomedical Research, University of Genova, Genova, Italy
| | - Cinzia Tortorella
- Department of Neuroscience, Section of Anatomy, University of Padova, Padova, Italy
| | - Guido Maura
- Department of Pharmacy and Center of Excellence for Biomedical Research, University of Genova, Genova, Italy
| | - Luigi F Agnati
- Department of Biomedical Sciences, University of Modena and Reggio Emilia, Modena, Italy; Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
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Guidolin D, Marcoli M, Tortorella C, Maura G, Agnati LF. G protein-coupled receptor-receptor interactions give integrative dynamics to intercellular communication. Rev Neurosci 2018; 29:703-726. [DOI: 10.1515/revneuro-2017-0087] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 01/01/2018] [Indexed: 01/14/2023]
Abstract
Abstract
The proposal of receptor-receptor interactions (RRIs) in the early 1980s broadened the view on the role of G protein-coupled receptors (GPCR) in the dynamics of the intercellular communication. RRIs, indeed, allow GPCR to operate not only as monomers but also as receptor complexes, in which the integration of the incoming signals depends on the number, spatial arrangement, and order of activation of the protomers forming the complex. The main biochemical mechanisms controlling the functional interplay of GPCR in the receptor complexes are direct allosteric interactions between protomer domains. The formation of these macromolecular assemblies has several physiologic implications in terms of the modulation of the signaling pathways and interaction with other membrane proteins. It also impacts on the emerging field of connectomics, as it contributes to set and tune the synaptic strength. Furthermore, recent evidence suggests that the transfer of GPCR and GPCR complexes between cells via the exosome pathway could enable the target cells to recognize/decode transmitters and/or modulators for which they did not express the pertinent receptors. Thus, this process may also open the possibility of a new type of redeployment of neural circuits. The fundamental aspects of GPCR complex formation and function are the focus of the present review article.
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Affiliation(s)
- Diego Guidolin
- Department of Neuroscience , University of Padova, via Gabelli 65 , I-35121 Padova , Italy
| | - Manuela Marcoli
- Department of Pharmacy and Center of Excellence for Biomedical Research , University of Genova , I-16126 Genova , Italy
| | - Cinzia Tortorella
- Department of Neuroscience , University of Padova, via Gabelli 65 , I-35121 Padova , Italy
| | - Guido Maura
- Department of Pharmacy and Center of Excellence for Biomedical Research , University of Genova , I-16126 Genova , Italy
| | - Luigi F. Agnati
- Department of Biomedical Sciences , University of Modena and Reggio Emilia , I-41121 Modena , Italy
- Department of Neuroscience , Karolinska Institutet , S-17177 Stockholm , Sweden
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Guidolin D, Marcoli M, Maura G, Agnati LF. New dimensions of connectomics and network plasticity in the central nervous system. Rev Neurosci 2018; 28:113-132. [PMID: 28030363 DOI: 10.1515/revneuro-2016-0051] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Accepted: 09/20/2016] [Indexed: 12/24/2022]
Abstract
Cellular network architecture plays a crucial role as the structural substrate for the brain functions. Therefore, it represents the main rationale for the emerging field of connectomics, defined as the comprehensive study of all aspects of central nervous system connectivity. Accordingly, in the present paper the main emphasis will be on the communication processes in the brain, namely wiring transmission (WT), i.e. the mapping of the communication channels made by cell components such as axons and synapses, and volume transmission (VT), i.e. the chemical signal diffusion along the interstitial brain fluid pathways. Considering both processes can further expand the connectomics concept, since both WT-connectomics and VT-connectomics contribute to the structure of the brain connectome. A consensus exists that such a structure follows a hierarchical or nested architecture, and macro-, meso- and microscales have been defined. In this respect, however, several lines of evidence indicate that a nanoscale (nano-connectomics) should also be considered to capture direct protein-protein allosteric interactions such as those occurring, for example, in receptor-receptor interactions at the plasma membrane level. In addition, emerging evidence points to novel mechanisms likely playing a significant role in the modulation of intercellular connectivity, increasing the plasticity of the system and adding complexity to its structure. In particular, the roamer type of VT (i.e. the intercellular transfer of RNA, proteins and receptors by extracellular vesicles) will be discussed since it allowed us to introduce a new concept of 'transient changes of cell phenotype', that is the transient acquisition of new signal release capabilities and/or new recognition/decoding apparatuses.
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Agnati LF, Guidolin D, Maura G, Marcoli M. Functional roles of three cues that provide nonsynaptic modes of communication in the brain: electromagnetic field, oxygen, and carbon dioxide. J Neurophysiol 2017; 119:356-368. [PMID: 29070628 DOI: 10.1152/jn.00413.2017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The integrative actions of the brain depend on the exchange of information among its computational elements. Hence, this phenomenon plays the key role in driving the complex dynamics of the central nervous system, in which true computations interact with noncomputational dynamical processes to generate brain representations of the body and of the body in the external world, and hence the finalistic behavior of the organism. In this context, it should be pointed out that, besides the intercellular interactions mediated by classical electrochemical signals, other types of interactions, namely, "cues" and "coercions," also appear to be exploited by the system to achieve its function. The present review focuses mainly on cues present in the environment and on those produced by cells of the body, which "pervade" the brain and contribute to its dynamics. These cues can also be metabolic substrates, and, in most cases, they are of fundamental importance to brain function and the survival of the entire organism. Three of these highly pervasive cues will be analyzed in greater detail, namely, oxygen, carbon dioxide, and electromagnetic fields (EMF). Special emphasis will be placed on EMF, since several authors have suggested that these highly pervasive energy fluctuations may play an important role in the global integrative actions of the brain; hence, EMF signaling may transcend classical connectionist models of brain function. Thus the new concept of "broadcasted neuroconnectomics" has been introduced, which transcends the current connectomics view of the brain.
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Affiliation(s)
- Luigi F Agnati
- Department of Diagnostics, Clinical Medicine and Public Health, University of Modena and Reggio Emilia , Modena , Italy.,Department of Neuroscience, Karolinska Institutet , Stockholm , Sweden
| | - Diego Guidolin
- Department of Neuroscience, University of Padova , Padua , Italy
| | - Guido Maura
- Department of Pharmacy and Center of Excellence for Biomedical Research, University of Genova , Genoa , Italy
| | - Manuela Marcoli
- Department of Pharmacy and Center of Excellence for Biomedical Research, University of Genova , Genoa , Italy
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Kshitiz, Afzal J, Suhail Y, Ahn EH, Goyal R, Hubbi ME, Hussaini Q, Ellison DD, Goyal J, Nacev B, Kim DH, Lee JH, Frankel S, Gray K, Bankoti R, Chien AJ, Levchenko A. Control of the interface between heterotypic cell populations reveals the mechanism of intercellular transfer of signaling proteins. Integr Biol (Camb) 2015; 7:364-72. [PMID: 25784457 PMCID: PMC11056238 DOI: 10.1039/c4ib00209a] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Direct intercellular transfer of cellular components is a recently described general mechanism of cell–cell communication. It is a more non-specific mode of intercellular communication that is not actively controlled by the participating cells. Though membrane bound proteins and small non-protein cytosolic components have been shown to be transferred between cells, the possibility of transfer of cytosolic proteins has not been clearly established, and its mechanism remains unexplained. Using a cell–cell pair of metastatic melanoma and endothelial cells, known to interact at various stages during cancer progression, we show that cytosolic proteins can indeed be transferred between heterotypic cells. Using precise relative cell patterning we provide evidence that this transfer depends on extent of the interface between heterotypic cell populations. This result is further supported by a mathematical model capturing various experimental conditions. We further demonstrate that cytosolic protein transfer can have important functional consequences for the tumor–stroma interactions, e.g., in heterotypic transfer of constitutively activated BRAF, a common melanoma associated mutation, leading to an enhanced activation of the downstream MAPK pathway. Our results suggest that cytosolic protein transfer can have important consequences for regulation of processes involving physical co-location of heterotypic cell types, particularly in invasive cancer growth.
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Guidolin D, Agnati LF, Marcoli M, Borroto-Escuela DO, Fuxe K. G-protein-coupled receptor type A heteromers as an emerging therapeutic target. Expert Opin Ther Targets 2014; 19:265-83. [PMID: 25381716 DOI: 10.1517/14728222.2014.981155] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION The discovery of receptor-receptor interactions (RRIs) in the early 1980s provided evidence that G-protein-coupled receptors (GPCRs) operate not only as monomers but also as heteromers, in which integration of the incoming signals takes place already at the plasma membrane level through allosteric RRIs. These integrative mechanisms give sophisticated dynamics to the structure and function of these receptor assemblies in terms of modulation of recognition, G-protein signaling and selectivity and switching to β-arrestin signaling. AREAS COVERED The present review briefly describes the concept of direct RRI and the available data on the mechanisms of oligomer formation. Further, pharmacological data concerning the best characterized heteromers involving type A GPCRs will be analyzed to evaluate their profile as possible targets for the treatment of various diseases, in particular of impacting diseases of the CNS. EXPERT OPINION GPCR heteromers have the potential to open a completely new field for pharmacology with likely a major impact in molecular medicine. Novel pharmacological strategies for the treatment of several pathologies have already been proposed. However, several challenges still exist to accurately characterize the role of the identified heteroreceptor complexes in pathology and to develop heteromer-specific ligands capable of efficiently exploiting their pharmacological features.
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Affiliation(s)
- Diego Guidolin
- University of Padova, Department of Molecular Medicine , via Gabelli 65, 35121 Padova , Italy +39 049 8272316 ; +39 049 8272319 ;
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Information handling by the brain: proposal of a new "paradigm" involving the roamer type of volume transmission and the tunneling nanotube type of wiring transmission. J Neural Transm (Vienna) 2014; 121:1431-49. [PMID: 24866694 DOI: 10.1007/s00702-014-1240-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Accepted: 05/06/2014] [Indexed: 12/13/2022]
Abstract
The current view on the organization of the central nervous system (CNS) is basically anchored to the paradigm describing the brain as formed by networks of neurons interconnected by synapses. Synaptic contacts are a fundamental characteristic for describing CNS operations, but increasing evidence accumulated in the last 30 years pointed to a refinement of this view. A possible overcoming of the classical "neuroscience paradigm" will be here outlined, based on the following hypotheses: (1) the basic morpho-functional unit in the brain is a compartment of tissue (functional module) where different resident cells (not only neurons) work as an integrated unit; (2) in these complex networks, a spectrum of intercellular communication processes is exploited, that can be classified according to a dichotomous criterion: wiring transmission (occurring through physically delimited channels) and volume transmission (exploiting diffusion in the extracellular space); (3) the connections between cells can themselves be described as a network, leading to an information processing occurring at different levels from cell network down to molecular level; (4) recent evidence of the existence of specialized structures (microvesicles and tunneling nanotubes) for intercellular exchange of materials, could allow a further type of polymorphism of the CNS networks based on at least transient changes in cell phenotype. When compared to the classical paradigm, the proposed scheme of cellular organization could allow a strong increase of the degrees of freedom available to the whole system and then of its plasticity. Furthermore, long range coordination and correlation can be more easily accommodated within this framework.
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Octopamine neuromodulation regulates Gr32a-linked aggression and courtship pathways in Drosophila males. PLoS Genet 2014; 10:e1004356. [PMID: 24852170 PMCID: PMC4031044 DOI: 10.1371/journal.pgen.1004356] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 03/24/2014] [Indexed: 01/08/2023] Open
Abstract
Chemosensory pheromonal information regulates aggression and reproduction in many species, but how pheromonal signals are transduced to reliably produce behavior is not well understood. Here we demonstrate that the pheromonal signals detected by Gr32a-expressing chemosensory neurons to enhance male aggression are filtered through octopamine (OA, invertebrate equivalent of norepinephrine) neurons. Using behavioral assays, we find males lacking both octopamine and Gr32a gustatory receptors exhibit parallel delays in the onset of aggression and reductions in aggression. Physiological and anatomical experiments identify Gr32a to octopamine neuron synaptic and functional connections in the suboesophageal ganglion. Refining the Gr32a-expressing population indicates that mouth Gr32a neurons promote male aggression and form synaptic contacts with OA neurons. By restricting the monoamine neuron target population, we show that three previously identified OA-FruM neurons involved in behavioral choice are among the Gr32a-OA connections. Our findings demonstrate that octopaminergic neuromodulatory neurons function as early as a second-order step in this chemosensory-driven male social behavior pathway. To mate or fight? When meeting other members of their species, male fruit flies must determine whether a second fly is male or female and proceed with the appropriate behavioral patterns. The taste receptor, Gr32a, has been reported to respond to chemical messages (pheromones) that are important for gender recognition, as eliminating Gr32a function impairs both male courtship and aggressive behavior. Here we demonstrate that different subsets of Gr32a-expressing neuron populations mediate these mutually exclusive behaviors and the male Gr32a-mediated behavioral response is amplified through neurons that contain the neuromodulator octopamine (OA, an invertebrate equivalent of norepinephrine). Gr32a-expressing neurons connect functionally and synaptically with distinct OA neurons indicating these amine neurons may function as early as a second-order step in a chemosensory-driven circuit. Our results contribute to understanding how an organism selects an appropriate behavioral response upon receiving external sensory signals.
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Spiegelberg BD. G protein coupled-receptor signaling and reversible lysine acetylation. J Recept Signal Transduct Res 2013; 33:261-6. [PMID: 23895385 DOI: 10.3109/10799893.2013.822889] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Emerging data suggest that interaction with reversible protein acetylation is an important mediator of GPCR-initiated changes in transcription and other processes. Alteration of acetylation downstream of GPCR activation occurs through a variety of mechanisms, including kinase-dependent and -independent regulation of histone deacetylases (HDACs) and histone acetyltransferases (HATs). The prominence of both GPCR and acetylation in pathology and drug development efforts highlights the importance of understanding cross-talk between these two signaling mechanisms.
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Affiliation(s)
- Bryan D Spiegelberg
- Department of Chemistry and Biochemistry, Rider University , New Jersey , USA
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Gonda DD, Akers JC, Kim R, Kalkanis SN, Hochberg FH, Chen CC, Carter BS. Neuro-oncologic Applications of Exosomes, Microvesicles, and Other Nano-Sized Extracellular Particles. Neurosurgery 2013; 72:501-10. [DOI: 10.1227/neu.0b013e3182846e63] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
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Peptide inhibitors disrupt the serotonin 5-HT2C receptor interaction with phosphatase and tensin homolog to allosterically modulate cellular signaling and behavior. J Neurosci 2013; 33:1615-30. [PMID: 23345234 DOI: 10.1523/jneurosci.2656-12.2013] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Serotonin (5-hydroxytryptamine; 5-HT) signaling through the 5-HT(2C) receptor (5-HT(2C)R) is essential in normal physiology, whereas aberrant 5-HT(2C)R function is thought to contribute to the pathogenesis of multiple neural disorders. The 5-HT(2C)R interacts with specific protein partners, but the impact of such interactions on 5-HT(2C)R function is poorly understood. Here, we report convergent cellular and behavioral data that the interaction between the 5-HT(2C)R and protein phosphatase and tensin homolog (PTEN) serves as a regulatory mechanism to control 5-HT(2C)R-mediated biology but not that of the closely homologous 5-HT(2A)R. A peptide derived from the third intracellular loop of the human 5-HT(2C)R [3L4F (third loop, fourth fragment)] disrupted the association, allosterically augmented 5-HT(2C)R-mediated signaling in live cells, and acted as a positive allosteric modulator in rats in vivo. We identified the critical residues within an 8 aa fragment of the 3L4F peptide that maintained efficacy (within the picomolar range) in live cells similar to that of the 3L4F peptide. Last, molecular modeling identified key structural features and potential interaction sites of the active 3L4F peptides against PTEN. These compelling data demonstrate the specificity and importance of this protein assembly in cellular events and behaviors mediated by 5-HT(2C)R signaling and provide a chemical guidepost to the future development of drug-like peptide or small-molecule inhibitors as neuroprobes to study 5-HT(2C)R allostery and therapeutics for 5-HT(2C)R-mediated disorders.
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Modeling intercellular transfer of biomolecules through tunneling nanotubes. Bull Math Biol 2013; 75:1400-16. [PMID: 23417627 DOI: 10.1007/s11538-013-9819-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2012] [Accepted: 01/21/2013] [Indexed: 10/27/2022]
Abstract
Tunneling nanotubes (TNTs) have previosly been observed as long and thin transient structures forming between cells and intercellular protein transfer through them has been experimentally verified. It is hypothesized that this may be a physiologically important means of cell-cell communication. This paper attempts to give a simple model for the rates of transfer of molecules across these TNTs at different distances. We describe the transfer of both cytosolic and membrane bound molecules between neighboring populations of cells and argue how the lifetime of the TNT, the diffusion rate, distance between cells, and the size of the molecules may affect their transfer. The model described makes certain predictions and opens a number of questions to be explored experimentally.
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Agnati LF, Guidolin D, Guescini M, Battistin L, Stocchi V, De Caro R, Genedani S, Fuxe K. Aspects on the integrative actions of the brain from neural networks to "brain-body medicine". J Recept Signal Transduct Res 2012; 32:163-80. [PMID: 22620712 DOI: 10.3109/10799893.2012.687748] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
"Integration" is a key term in describing how nervous system can perform high level functions. A first condition to have "integration" is obviously the presence of efficient "communication processes" among the parts that have to be combined into the harmonious whole. In this respect, two types of communication processes, called wiring transmission (WT) and volume transmission (VT), respectively, were found to play a major role in the nervous system, allowing the exchange of signals not only between neurons, but rather among all cell types present in the central nervous system (CNS). A second fundamental aspect of a communication process is obviously the recognition/decoding process at target level. As far as this point is concerned, increasing evidence emphasizes the importance of supramolecular complexes of receptors (the so called receptor mosaics) generated by direct receptor-receptor interactions. Their assemblage would allow a first integration of the incoming information already at the plasma membrane level. Recently, evidence of two new subtypes of WT and VT has been obtained, namely the tunnelling nanotubes mediated WT and the microvesicle (in particular exosomes) mediated VT allowing the horizontal transfer of bioactive molecules, including receptors, RNAs and micro-RNAs. The physiological and pathological implications of these types of communication have opened up a new field that is largely still unexplored. In fact, likely unsuspected integrative actions of the nervous system could occur. In this context, a holistic approach to the brain-body complex as an indissoluble system has been proposed. Thus, the hypothesis has been introduced on the existence of a brain-body integrative structure formed by the "area postrema/nucleus tractus solitarius" (AP/NTS) and the "anteroventral third ventricle region/basal hypothalamus with the median eminence" (AV3V-BH). These highly interconnected regions operate as specialized interfaces between the brain and the body integrating brain-borne and body-borne neural and humoral signals.
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Microvesicle and tunneling nanotube mediated intercellular transfer of g-protein coupled receptors in cell cultures. Exp Cell Res 2012; 318:603-13. [PMID: 22266577 DOI: 10.1016/j.yexcr.2012.01.005] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2011] [Revised: 12/27/2011] [Accepted: 01/03/2012] [Indexed: 01/10/2023]
Abstract
Recent evidence shows that cells exchange collections of signals via microvesicles (MVs) and tunneling nano-tubes (TNTs). In this paper we have investigated whether in cell cultures GPCRs can be transferred by means of MVs and TNTs from a source cell to target cells. Western blot, transmission electron microscopy and gene expression analyses demonstrate that A(2A) and D(2) receptors are present in released MVs. In order to further demonstrate the involvement of MVs in cell-to-cell communication we created two populations of cells (HEK293T and COS-7) transiently transfected with D(2)R-CFP or A(2A)R-YFP. These two types of cells were co-cultured, and FRET analysis demonstrated simultaneously positive cells to the D(2)R-CFP and A(2A)R-YFP. Fluorescence microscopy analysis also showed that GPCRs can move from one cell to another also by means of TNTs. Finally, recipient cells pre-incubated for 24 h with A(2A)R positive MVs were treated with the adenosine A(2A) receptor agonist CGS-21680. The significant increase in cAMP accumulation clearly demonstrated that A(2A)Rs were functionally competent in target cells. These findings demonstrate that A(2A) receptors capable of recognizing and decoding extracellular signals can be safely transferred via MVs from source to target cells.
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On the origin of the triplet puzzle of homologies in receptor heteromers: Toll-like receptor triplets in different types of receptors. J Neural Transm (Vienna) 2011; 119:517-23. [PMID: 22068823 DOI: 10.1007/s00702-011-0734-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2011] [Accepted: 10/26/2011] [Indexed: 10/15/2022]
Abstract
Based on our theory, we have discovered main triplets of amino acid residues in the GABAB1 receptor and several other neural receptors, which seem to originate from toll-like receptors and appear also as homologies in receptor heteromers. The obtained results strengthen our hypothesis that these triplets may 'guide-and-clasp' receptor-receptor interactions.
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