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Pallaki P, Georganta EM, Serafimidis I, Papakonstantinou MP, Papanikolaou V, Koutloglou S, Papadimitriou E, Agalou A, Tserga A, Simeonof A, Thomaidou D, Gaitanou M, Georgoussi Z. A novel regulatory role of RGS4 in STAT5B activation, neurite outgrowth and neuronal differentiation. Neuropharmacology 2017; 117:408-421. [PMID: 28219718 DOI: 10.1016/j.neuropharm.2017.02.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 02/01/2017] [Accepted: 02/14/2017] [Indexed: 12/26/2022]
Abstract
The Regulator of G protein Signalling 4 (RGS4) is a multitask protein that interacts with and negatively modulates opioid receptor signalling. Previously, we showed that the δ-opioid receptor (δ-OR) forms a multiprotein signalling complex consisting of Gi/Go proteins and the Signal Transducer and Activator of Transcription 5B (STAT5B) that leads to neuronal differentiation and neurite outgrowth upon δ-ΟR activation. Here, we investigated whether RGS4 could participate in signalling pathways to regulate neurotropic events. We demonstrate that RGS4 interacts directly with STAT5B independently of δ-ΟR presence both in vitro and in living cells. This interaction involves the N-terminal portion of RGS4 and the DNA-binding SH3 domain of STAT5B. Expression of RGS4 in HEK293 cells expressing δ-OR and/or erythropoietin receptor results in inhibition of [D-Ser2, Leu5, Thr6]-enkephalin (DSLET)-and erythropoietin-dependent STAT5B phosphorylation and subsequent transcriptional activation. DSLET-dependent neurite outgrowth of neuroblastoma cells is also blocked by RGS4 expression, whereas primary cortical cultures of RGS4 knockout mice (RGS4-/-) exhibit enhanced neuronal sprouting after δ-OR activation. Additional studies in adult brain extracts from RGS4-/- mice revealed increased levels of p-STAT5B. Finally, neuronal progenitor cultures from RGS4-/- mice exhibit enhanced proliferation with concomitant increases in the mRNA levels of the anti-apoptotic STAT5B target genes bcl2 and bcl-xl. These observations suggest that RGS4 is implicated in opioid dependent neuronal differentiation and neurite outgrowth via a "non-canonical" signaling pathway regulating STAT5B-directed responses.
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Affiliation(s)
- Paschalina Pallaki
- Laboratory of Cellular Signalling and Molecular Pharmacology, Institute of Biosciences and Applications, National Centre for Scientific Research «Demokritos», 15310 Athens, Greece
| | - Eirini-Maria Georganta
- Laboratory of Cellular Signalling and Molecular Pharmacology, Institute of Biosciences and Applications, National Centre for Scientific Research «Demokritos», 15310 Athens, Greece
| | - Ioannis Serafimidis
- Laboratory of Developmental Biology, Biomedical Research Foundation of the Academy of Athens, 11527 Athens, Greece
| | - Maria-Pagona Papakonstantinou
- Laboratory of Cellular Signalling and Molecular Pharmacology, Institute of Biosciences and Applications, National Centre for Scientific Research «Demokritos», 15310 Athens, Greece
| | - Vassilis Papanikolaou
- Laboratory of Cellular Signalling and Molecular Pharmacology, Institute of Biosciences and Applications, National Centre for Scientific Research «Demokritos», 15310 Athens, Greece
| | - Sofia Koutloglou
- Laboratory of Cellular Signalling and Molecular Pharmacology, Institute of Biosciences and Applications, National Centre for Scientific Research «Demokritos», 15310 Athens, Greece
| | - Elsa Papadimitriou
- Laboratory of Cellular and Molecular Neurobiology, Hellenic Pasteur Institute, 11521 Athens, Greece
| | - Adamantia Agalou
- Laboratory of Cellular Signalling and Molecular Pharmacology, Institute of Biosciences and Applications, National Centre for Scientific Research «Demokritos», 15310 Athens, Greece
| | - Aggeliki Tserga
- Laboratory of Cellular Signalling and Molecular Pharmacology, Institute of Biosciences and Applications, National Centre for Scientific Research «Demokritos», 15310 Athens, Greece
| | - Alexandra Simeonof
- Laboratory of Cellular Signalling and Molecular Pharmacology, Institute of Biosciences and Applications, National Centre for Scientific Research «Demokritos», 15310 Athens, Greece
| | - Dimitra Thomaidou
- Laboratory of Cellular and Molecular Neurobiology, Hellenic Pasteur Institute, 11521 Athens, Greece
| | - Maria Gaitanou
- Laboratory of Cellular and Molecular Neurobiology, Hellenic Pasteur Institute, 11521 Athens, Greece
| | - Zafiroula Georgoussi
- Laboratory of Cellular Signalling and Molecular Pharmacology, Institute of Biosciences and Applications, National Centre for Scientific Research «Demokritos», 15310 Athens, Greece.
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