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Kitamura K, Homma T, Sohel MSH, Fuyuki A, Miyawaki S, Onouchi S, Saito S. Expression patterns of prosaposin and its receptors, G protein-coupled receptor (GPR) 37 and GPR37L1, in the mouse olfactory organ. Tissue Cell 2023; 82:102093. [PMID: 37075680 DOI: 10.1016/j.tice.2023.102093] [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: 01/29/2023] [Revised: 03/24/2023] [Accepted: 04/14/2023] [Indexed: 04/21/2023]
Abstract
Prosaposin is a glycoprotein conserved widely in vertebrates, because it is a precursor for saposins that are required for normal lysosomal function and thus for autophagy, and acts as a neurotrophic factor. Most tetrapods possess two kinds of olfactory neuroepithelia, namely, the olfactory epithelium (OE) and the vomeronasal epithelium (VNE). This study examined the expression patterns of prosaposin and its candidate receptors, G protein-coupled receptor (GPR) 37 and GPR37L1, in mouse OE and VNE by immunofluorescence and in situ hybridization. Prosaposin immunoreactivity was observed in the olfactory receptor neurons, vomeronasal receptor neurons, Bowman's gland (BG), and Jacobson's gland (JG). Prosaposin expression was mainly observed in mature neurons. Prosaposin mRNA expression was observed not only in these cells but also in the apical region of the VNE. GPR37 and GPR37L1 immunoreactivities were found only in the BG and/or the JG. Prosaposin was suggested to secrete and facilitate the autophagic activities of the neurons and modulate the mucus secretion in mouse olfactory organ.
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Affiliation(s)
- Kai Kitamura
- Laboratory of Veterinary Anatomy, Faculty of Applied Biological Sciences, Gifu University, Gifu, Japan
| | - Takeshi Homma
- Laboratory of Veterinary Anatomy, Joint Graduate School of Veterinary Sciences, Gifu University, 1-1 Yanagido, Gifu, Japan
| | - Md Shahriar Hasan Sohel
- Laboratory of Veterinary Anatomy, Joint Graduate School of Veterinary Sciences, Gifu University, 1-1 Yanagido, Gifu, Japan
| | - Aimi Fuyuki
- Laboratory of Veterinary Anatomy, Faculty of Applied Biological Sciences, Gifu University, Gifu, Japan
| | - Shingo Miyawaki
- Laboratory of Veterinary Surgery, Faculty of Applied Biological Sciences, Gifu University, Gifu, Japan
| | - Sawa Onouchi
- Laboratory of Veterinary Anatomy, Faculty of Applied Biological Sciences, Gifu University, Gifu, Japan; Laboratory of Veterinary Anatomy, Joint Graduate School of Veterinary Sciences, Gifu University, 1-1 Yanagido, Gifu, Japan
| | - Shouichiro Saito
- Laboratory of Veterinary Anatomy, Faculty of Applied Biological Sciences, Gifu University, Gifu, Japan; Laboratory of Veterinary Anatomy, Joint Graduate School of Veterinary Sciences, Gifu University, 1-1 Yanagido, Gifu, Japan.
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Meyer RC, Giddens MM, Coleman BM, Hall RA. The protective role of prosaposin and its receptors in the nervous system. Brain Res 2014; 1585:1-12. [PMID: 25130661 DOI: 10.1016/j.brainres.2014.08.022] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Revised: 07/18/2014] [Accepted: 08/10/2014] [Indexed: 12/12/2022]
Abstract
Prosaposin (also known as SGP-1) is an intriguing multifunctional protein that plays roles both intracellularly, as a regulator of lysosomal enzyme function, and extracellularly, as a secreted factor with neuroprotective and glioprotective effects. Following secretion, prosaposin can undergo endocytosis via an interaction with the low-density lipoprotein-related receptor 1 (LRP1). The ability of secreted prosaposin to promote protective effects in the nervous system is known to involve activation of G proteins, and the orphan G protein-coupled receptors GPR37 and GPR37L1 have recently been shown to mediate signaling induced by both prosaposin and a fragment of prosaposin known as prosaptide. In this review, we describe recent advances in our understanding of prosaposin, its receptors and their importance in the nervous system.
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Affiliation(s)
- Rebecca C Meyer
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322, United States
| | - Michelle M Giddens
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322, United States
| | - Brilee M Coleman
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322, United States
| | - Randy A Hall
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322, United States.
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