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Korchynska S, Lutz MI, Borók E, Pammer J, Cinquina V, Fedirko N, Irving AJ, Mackie K, Harkany T, Keimpema E. GPR55 controls functional differentiation of self-renewing epithelial progenitors for salivation. JCI Insight 2019; 4:122947. [PMID: 30830860 PMCID: PMC6478415 DOI: 10.1172/jci.insight.122947] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 01/11/2019] [Indexed: 12/17/2022] Open
Abstract
GPR55, a lipid-sensing receptor, is implicated in cell cycle control, malignant cell mobilization, and tissue invasion in cancer. However, a physiological role for GPR55 is virtually unknown for any tissue type. Here, we localize GPR55 to self-renewing ductal epithelial cells and their terminally differentiated progeny in both human and mouse salivary glands. Moreover, we find GPR55 expression downregulated in salivary gland mucoepidermoid carcinomas and GPR55 reinstatement by antitumor irradiation, suggesting that GPR55 controls renegade proliferation. Indeed, GPR55 antagonism increases cell proliferation and function determination in quasiphysiological systems. In addition, Gpr55-/- mice present ~50% enlarged submandibular glands with many more granulated ducts, as well as disordered endoplasmic reticuli and with glycoprotein content. Next, we hypothesized that GPR55 could also modulate salivation and glycoprotein content by entraining differentiated excretory progeny. Accordingly, GPR55 activation facilitated glycoprotein release by itself, inducing low-amplitude Ca2+ oscillations, as well as enhancing acetylcholine-induced Ca2+ responses. Topical application of GPR55 agonists, which are ineffective in Gpr55-/- mice, into adult rodent submandibular glands increased salivation and saliva glycoprotein content. Overall, we propose that GPR55 signaling in epithelial cells ensures both the life-long renewal of ductal cells and the continuous availability of saliva and glycoproteins for oral health and food intake.
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Affiliation(s)
| | | | - Erzsébet Borók
- Department of Molecular Neurosciences, Center for Brain Research
- Department of Cognitive Neurobiology, Centre for Brain Research, and
| | - Johannes Pammer
- Department of Pathology, Medical University of Vienna, Vienna, Austria
| | | | - Nataliya Fedirko
- Department of Human and Animal Physiology, Biological Faculty, Ivan Franko National University of Lviv, Lviv, Ukraine
| | - Andrew J. Irving
- School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Dublin, Ireland
| | - Ken Mackie
- Gill Center for Biomolecular Sciences, Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana, USA
| | - Tibor Harkany
- Department of Molecular Neurosciences, Center for Brain Research
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Erik Keimpema
- Department of Molecular Neurosciences, Center for Brain Research
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Malenczyk K, Girach F, Szodorai E, Storm P, Segerstolpe Å, Tortoriello G, Schnell R, Mulder J, Romanov RA, Borók E, Piscitelli F, Di Marzo V, Szabó G, Sandberg R, Kubicek S, Lubec G, Hökfelt T, Wagner L, Groop L, Harkany T. A TRPV1-to-secretagogin regulatory axis controls pancreatic β-cell survival by modulating protein turnover. EMBO J 2017; 36:2107-2125. [PMID: 28637794 PMCID: PMC5510001 DOI: 10.15252/embj.201695347] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 04/27/2017] [Accepted: 05/09/2017] [Indexed: 12/20/2022] Open
Abstract
Ca2+-sensor proteins are generally implicated in insulin release through SNARE interactions. Here, secretagogin, whose expression in human pancreatic islets correlates with their insulin content and the incidence of type 2 diabetes, is shown to orchestrate an unexpectedly distinct mechanism. Single-cell RNA-seq reveals retained expression of the TRP family members in β-cells from diabetic donors. Amongst these, pharmacological probing identifies Ca2+-permeable transient receptor potential vanilloid type 1 channels (TRPV1) as potent inducers of secretagogin expression through recruitment of Sp1 transcription factors. Accordingly, agonist stimulation of TRPV1s fails to rescue insulin release from pancreatic islets of glucose intolerant secretagogin knock-out(-/-) mice. However, instead of merely impinging on the SNARE machinery, reduced insulin availability in secretagogin-/- mice is due to β-cell loss, which is underpinned by the collapse of protein folding and deregulation of secretagogin-dependent USP9X deubiquitinase activity. Therefore, and considering the desensitization of TRPV1s in diabetic pancreata, a TRPV1-to-secretagogin regulatory axis seems critical to maintain the structural integrity and signal competence of β-cells.
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Affiliation(s)
- Katarzyna Malenczyk
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Vienna, Austria
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Fatima Girach
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Edit Szodorai
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Petter Storm
- Department of Clinical Sciences, Diabetes and Endocrinology CRC, Skåne University Hospital Malmö, Malmö, Sweden
| | - Åsa Segerstolpe
- Integrated Cardio Metabolic Centre, Karolinska Institutet, Huddinge, Sweden
| | | | - Robert Schnell
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Jan Mulder
- Science for Life Laboratory, Karolinska Institutet, Solna, Sweden
| | - Roman A Romanov
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Vienna, Austria
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Erzsébet Borók
- Department of Cognitive Neurobiology, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Fabiana Piscitelli
- Endocannabinoid Research Group, Istituto di Chimica Biomolecolare, Consiglio Nazionale delle Ricerche, Pozzuoli Naples, Italy
| | - Vincenzo Di Marzo
- Endocannabinoid Research Group, Istituto di Chimica Biomolecolare, Consiglio Nazionale delle Ricerche, Pozzuoli Naples, Italy
| | - Gábor Szabó
- Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | - Rickard Sandberg
- Integrated Cardio Metabolic Centre, Karolinska Institutet, Huddinge, Sweden
| | - Stefan Kubicek
- CeMM Research Centre for Molecular Medicine, Vienna, Austria
| | - Gert Lubec
- Department of Pharmaceutical Chemistry, University of Vienna, Vienna, Austria
| | - Tomas Hökfelt
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Ludwig Wagner
- University Clinic for Internal Medicine III, General Hospital Vienna, Vienna, Austria
| | - Leif Groop
- Department of Clinical Sciences, Diabetes and Endocrinology CRC, Skåne University Hospital Malmö, Malmö, Sweden
| | - Tibor Harkany
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Vienna, Austria
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
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