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Abstract
Pleiotrophin (PTN) is a potent mitogenic cytokine with a high affinity for the polysaccharide glycosaminoglycan (GAG). Although it is most strongly associated with neural development during embryogenesis and the neonatal period, its expression has also been linked to a plethora of other physiological events including cancer metastasis, angiogenesis, bone development, and inflammation. A considerable amount of research has been carried out to understand the mechanisms by which PTN regulates these events. In particular, PTN has now been shown to bind a diverse collection of receptors including many GAG-containing proteoglycans. These interactions lead to the activation of many intracellular kinases and, ultimately, activation and transformation of cells. Structural studies of PTN in complex with both GAG and domains from its non-proteoglycan receptors reveal a binding mechanism that relies on electrostatic interactions and points to PTN-induced receptor oligomerization as one of the possible ways PTN uses to control cellular functions.
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Bertram S, Roll L, Reinhard J, Groß K, Dazert S, Faissner A, Volkenstein S. Pleiotrophin increases neurite length and number of spiral ganglion neurons in vitro. Exp Brain Res 2019; 237:2983-2993. [PMID: 31515588 DOI: 10.1007/s00221-019-05644-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 09/03/2019] [Indexed: 11/28/2022]
Abstract
Acoustic trauma, aging, genetic defects or ototoxic drugs are causes for sensorineural hearing loss involving sensory hair cell death and secondary degeneration of spiral ganglion neurons. Auditory implants are the only available therapy for severe to profound sensorineural hearing loss when hearing aids do not provide a sufficient speech discrimination anymore. Neurotrophic factors represent potential therapeutic candidates to improve the performance of cochlear implants (CIs) by the support of spiral ganglion neurons (SGNs). Here, we investigated the effect of pleiotrophin (PTN), a well-described neurotrophic factor for different types of neurons that is expressed in the postnatal mouse cochlea. PTN knockout mice exhibit severe deficits in auditory brainstem responses, which indicates the importance of PTN in inner ear development and function and makes it a promising candidate to support SGNs. Using organotypic explants and dissociated SGN cultures, we investigated the influence of PTN on the number of neurons, neurite number and neurite length. PTN significantly increased the number and neurite length of dissociated SGNs. We further verified the expression of important PTN-associated receptors in the SG. mRNA of anaplastic lymphoma kinase, αv integrin, β3 integrin, receptor protein tyrosine phosphatase β/ζ, neuroglycan C, low-density lipoprotein receptor-related protein 1 and syndecan 3 was detected in the inner ear. These results suggest that PTN may be a novel candidate to improve sensorineural hearing loss treatment in the future.
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Affiliation(s)
- Sebastian Bertram
- Department of Otorhinolaryngology, Head and Neck Surgery, St. Elisabeth-Hospital, Ruhr-University Bochum, Bleichstr. 15, 44787, Bochum, Germany
| | - Lars Roll
- Department of Cell Morphology and Molecular Neurobiology, Faculty of Biology and Biotechnology, Ruhr-University Bochum, Universitätsstr. 150, 44801, Bochum, Germany
| | - Jacqueline Reinhard
- Department of Cell Morphology and Molecular Neurobiology, Faculty of Biology and Biotechnology, Ruhr-University Bochum, Universitätsstr. 150, 44801, Bochum, Germany
| | - Katharina Groß
- Department of Cell Morphology and Molecular Neurobiology, Faculty of Biology and Biotechnology, Ruhr-University Bochum, Universitätsstr. 150, 44801, Bochum, Germany
| | - Stefan Dazert
- Department of Otorhinolaryngology, Head and Neck Surgery, St. Elisabeth-Hospital, Ruhr-University Bochum, Bleichstr. 15, 44787, Bochum, Germany
| | - Andreas Faissner
- Department of Cell Morphology and Molecular Neurobiology, Faculty of Biology and Biotechnology, Ruhr-University Bochum, Universitätsstr. 150, 44801, Bochum, Germany
| | - Stefan Volkenstein
- Department of Otorhinolaryngology, Head and Neck Surgery, St. Elisabeth-Hospital, Ruhr-University Bochum, Bleichstr. 15, 44787, Bochum, Germany.
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Lampropoulou E, Logoviti I, Koutsioumpa M, Hatziapostolou M, Polytarchou C, Skandalis SS, Hellman U, Fousteris M, Nikolaropoulos S, Choleva E, Lamprou M, Skoura A, Megalooikonomou V, Papadimitriou E. Cyclin-dependent kinase 5 mediates pleiotrophin-induced endothelial cell migration. Sci Rep 2018; 8:5893. [PMID: 29651006 PMCID: PMC5897396 DOI: 10.1038/s41598-018-24326-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 03/22/2018] [Indexed: 12/21/2022] Open
Abstract
Pleiotrophin (PTN) stimulates endothelial cell migration through binding to receptor protein tyrosine phosphatase beta/zeta (RPTPβ/ζ) and ανβ3 integrin. Screening for proteins that interact with RPTPβ/ζ and potentially regulate PTN signaling, through mass spectrometry analysis, identified cyclin-dependent kinase 5 (CDK5) activator p35 among the proteins displaying high sequence coverage. Interaction of p35 with the serine/threonine kinase CDK5 leads to CDK5 activation, known to be implicated in cell migration. Protein immunoprecipitation and proximity ligation assays verified p35-RPTPβ/ζ interaction and revealed the molecular association of CDK5 and RPTPβ/ζ. In endothelial cells, PTN activates CDK5 in an RPTPβ/ζ- and phosphoinositide 3-kinase (PI3K)-dependent manner. On the other hand, c-Src, ανβ3 and ERK1/2 do not mediate the PTN-induced CDK5 activation. Pharmacological and genetic inhibition of CDK5 abolished PTN-induced endothelial cell migration, suggesting that CDK5 mediates PTN stimulatory effect. A new pyrrolo[2,3-α]carbazole derivative previously identified as a CDK1 inhibitor, was found to suppress CDK5 activity and eliminate PTN stimulatory effect on cell migration, warranting its further evaluation as a new CDK5 inhibitor. Collectively, our data reveal that CDK5 is activated by PTN, in an RPTPβ/ζ-dependent manner, regulates PTN-induced cell migration and is an attractive target for the inhibition of PTN pro-angiogenic properties.
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Affiliation(s)
- Evgenia Lampropoulou
- Laboratory of Molecular Pharmacology, Department of Pharmacy, University of Patras, GR26504, Patras, Greece
| | - Ioanna Logoviti
- Laboratory of Molecular Pharmacology, Department of Pharmacy, University of Patras, GR26504, Patras, Greece
| | - Marina Koutsioumpa
- Laboratory of Molecular Pharmacology, Department of Pharmacy, University of Patras, GR26504, Patras, Greece.,Center for Systems Biomedicine, Vatche and Tamar Manoukian Division of Digestive Diseases, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA, 90095, USA
| | - Maria Hatziapostolou
- Department of Biosciences, School of Science and Technology, Nottingham Trent University, Nottingham, NG11 8NS, United Kingdom
| | - Christos Polytarchou
- Department of Biosciences, School of Science and Technology, Nottingham Trent University, Nottingham, NG11 8NS, United Kingdom
| | - Spyros S Skandalis
- Laboratory of Biochemistry, Department of Chemistry, University of Patras, GR26504, Patras, Greece.,Ludwig Institute for Cancer Research, Uppsala University, Uppsala, SE-751-05, Sweden
| | - Ulf Hellman
- Ludwig Institute for Cancer Research, Uppsala University, Uppsala, SE-751-05, Sweden
| | - Manolis Fousteris
- Laboratory of Medicinal Chemistry, Department of Pharmacy, University of Patras, GR26504, Patras, Greece
| | - Sotirios Nikolaropoulos
- Laboratory of Medicinal Chemistry, Department of Pharmacy, University of Patras, GR26504, Patras, Greece
| | - Efrosini Choleva
- Laboratory of Molecular Pharmacology, Department of Pharmacy, University of Patras, GR26504, Patras, Greece
| | - Margarita Lamprou
- Laboratory of Molecular Pharmacology, Department of Pharmacy, University of Patras, GR26504, Patras, Greece
| | - Angeliki Skoura
- Computer Engineering and Informatics Department, University of Patras, Patras, Greece
| | | | - Evangelia Papadimitriou
- Laboratory of Molecular Pharmacology, Department of Pharmacy, University of Patras, GR26504, Patras, Greece.
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