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Gao HL, Li C, Nabeka H, Shimokawa T, Wang ZY, Cao YM, Matsuda S. An 18-mer Peptide Derived from Prosaposin Ameliorates the Effects of Aβ1-42 Neurotoxicity on Hippocampal Neurogenesis and Memory Deficit in Mice. J Alzheimers Dis 2018; 53:1173-92. [PMID: 27372641 DOI: 10.3233/jad-160093] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The pathological hallmarks of Alzheimer's disease (AD) include amyloid-β (Aβ) accumulation, neurofibrillary tangle formation, synaptic dysfunction, and neuronal loss. The present study was performed to investigate the protective effects and mechanism of action of a prosaposin-derived 18-mer peptide (PS18: LSELIINNATEELLIKGL) on mice hippocampal progenitor cell proliferation, neurogenesis, and memory tasks after intracerebroventricular injection of Aβ1-42 peptide. Seven days after Aβ1-42 injection, significant proliferation of hippocampal progenitor cells and memory impairment were evident. Two weeks after Aβ1-42 peptide injection, elevated numbers of surviving 5-bromo-2-deoxyuridine cells and newly formed neurons were detected. Treatment with PS18 attenuated these effects evoked by Aβ1-42. Our data indicate that treatment with PS18 partially attenuated the increase in hippocampal neurogenesis caused by Aβ1-42-induced neuroinflammation and prevented memory deficits associated with increased numbers of activated glial cells. We observed an increase in ADAM10 and decreases in BACE1, PS1/2, and AβPP protein levels, suggesting that PS18 enhances the nonamyloidogenic AβPP cleavage pathway. Importantly, our results further showed that PS18 activated the PI3K/Akt pathway, phosphorylated GSK-3α/β, and, as a consequence, exerted a neuroprotective effect. In addition, PS18 showed a protective effect against Aβ1-42-induced neurotoxicity via suppression of the caspase pathway; upregulation of Bcl-2; downregulation of BAX, attenuating mitochondrial damage; and inhibition of caspase-3. These findings suggest that PS18 may provide a valuable therapeutic strategy for the treatment of progressive neurodegenerative diseases, such as AD.
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Affiliation(s)
- Hui-Ling Gao
- College of Life and Health Sciences, Northeastern University, Shenyang, China
| | - Cheng Li
- Department of Immunology, China Medical University, Shenyang, China
| | - Hiroaki Nabeka
- Department of Anatomy and Embryology, Ehime University Graduate School of Medicine, Toon, Ehime, Japan
| | - Tetsuya Shimokawa
- Department of Anatomy and Embryology, Ehime University Graduate School of Medicine, Toon, Ehime, Japan
| | - Zhan-You Wang
- College of Life and Health Sciences, Northeastern University, Shenyang, China
| | - Ya-Ming Cao
- Department of Immunology, China Medical University, Shenyang, China
| | - Seiji Matsuda
- Department of Anatomy and Embryology, Ehime University Graduate School of Medicine, Toon, Ehime, Japan
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Yoneshige A, Suzuki K, Kojima N, Matsuda J. Regional expression of prosaposin in the wild-type and saposin D-deficient mouse brain detected by an anti-mouse prosaposin-specific antibody. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2009; 85:422-434. [PMID: 19907127 PMCID: PMC3621563 DOI: 10.2183/pjab.85.422] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/25/2009] [Accepted: 10/05/2009] [Indexed: 05/28/2023]
Abstract
Prosaposin is a precursor of saposins A, B, C, and D. Saposins are indispensable for lysosomal hydrolysis of sphingolipids. The notion that prosaposin itself is likely involved in brain development led us to generate an anti-mouse prosaposin-specific antibody that do not cross-react with any of the processed saposins. We have used it to study expression of prosaposin in the brain of wild-type (WT) and saposin D knockout mice (Sap-D(-/-)). Immunoblot studies indicated that prosaposin, already abundant in the brain of WT, was dramatically increased in Sap-D(-/-). By immunohistochemistry, the brain of WT was rich in prosaposin in hippocampal CA3 pyramidal neurons, tufted cells and mitral cells in olfactory bulb, and cerebellar Purkinje cells. In Sap-D(-/-), immunoreactivity of prosaposin was increased in these neurons, most notably in the CA3 pyramidal neurons which contained prosaposin immuno-positive inclusion bodies in the endoplasmic reticulum. Further characterization of these prosaposin-rich neurons may provide new insights into the physiological functions of prosaposin in the nervous system.
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Affiliation(s)
- Azusa Yoneshige
- Institute of Glycoscience, Tokai University, Kanagawa,
Japan
| | - Kunihiko Suzuki
- Institute of Glycoscience, Tokai University, Kanagawa,
Japan
| | - Naoya Kojima
- Institute of Glycoscience, Tokai University, Kanagawa,
Japan
| | - Junko Matsuda
- Institute of Glycoscience, Tokai University, Kanagawa,
Japan
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Bruhn H. A short guided tour through functional and structural features of saposin-like proteins. Biochem J 2005; 389:249-57. [PMID: 15992358 PMCID: PMC1175101 DOI: 10.1042/bj20050051] [Citation(s) in RCA: 157] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
SAPLIPs (saposin-like proteins) are a diverse family of lipid-interacting proteins that have various and only partly understood, but nevertheless essential, cellular functions. Their existence is conserved in phylogenetically most distant organisms, such as primitive protozoa and mammals. Owing to their remarkable sequence variability, a common mechanism for their actions is not known. Some shared principles beyond their diversity have become evident by analysis of known three-dimensional structures. Whereas lipid interaction is the basis for their functions, the special cellular tasks are often defined by interaction partners other than lipids. Based on recent findings, this review summarizes phylogenetic relations, function and structural features of the members of this family.
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Affiliation(s)
- Heike Bruhn
- Research Center for Infectious Diseases, Röntgenring 11, D-97070 Würzburg, Germany.
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Lauc G, Heffer-Lauc M. Shedding and uptake of gangliosides and glycosylphosphatidylinositol-anchored proteins. Biochim Biophys Acta Gen Subj 2005; 1760:584-602. [PMID: 16388904 DOI: 10.1016/j.bbagen.2005.11.014] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2005] [Revised: 11/22/2005] [Accepted: 11/23/2005] [Indexed: 10/25/2022]
Abstract
Gangliosides and glycosylphosphatidylinositol (GPI)-anchored proteins have very different biosynthetic origin, but they have one thing in common: they are both comprised of a relatively large hydrophilic moiety tethered to a membrane by a relatively small lipid tail. Both gangliosides and GPI-anchored proteins can be actively shed from the membrane of one cell and taken up by other cells by insertion of their lipid anchors into the cell membrane. The process of shedding and uptake of gangliosides and GPI-anchored proteins has been independently discovered in several disciplines during the last few decades, but these discoveries were largely ignored by people working in other areas of science. By bringing together results from these, sometimes very distant disciplines, in this review, we give an overview of current knowledge about shedding and uptake of gangliosides and GPI-anchored proteins. Tumor cells and some pathogens apparently misuse this process for their own advantage, but its real physiological functions remain to be discovered.
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Affiliation(s)
- Gordan Lauc
- Department of Chemistry and Biochemistry, University of Osijek School of Medicine, Croatia.
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Cohen T, Ravid L, Altman N, Madar-Shapiro L, Fein A, Weil M, Horowitz M. Conservation of expression and alternative splicing in the prosaposin gene. ACTA ACUST UNITED AC 2005; 129:8-19. [PMID: 15469878 DOI: 10.1016/j.molbrainres.2004.06.027] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/14/2004] [Indexed: 10/26/2022]
Abstract
Prosaposin is the precursor of four lysosomal activator molecules known as saposins A, B, C and D. It is also secreted and was proposed to be a neurotrophic factor. The neurotrophic function was attributed to the amino terminus of saposin C. In man, mouse and rat prosaposin is transcribed to two major isoforms differing in the inclusion of 9 bps of exon 8 within the saposin B domain. In the present study, we show that there is evolutionary conservation of the prosaposin structure and alternative splicing in chick and zebrafish as well. Moreover, there is conservation in prosaposin expression as tested immunohistochemically in the mouse and chick developing brain. We developed a sensitive assay to quantitate the prosaposin alternatively spliced forms. Our results indicate that, in mouse brain, skeletal and cardiac muscle the exon 8-containing RNA is most abundant, while it is almost absent from visceral and smooth muscle-containing organs. We observed temporal and differential expression of the alternatively spliced prosaposin mRNAs in mouse and chick brain as well as during development. The elevation in the abundance of exon 8-containing prosaposin RNA during mouse and chick brain development may suggest a role for the exon 8-containing prosaposin form in this process.
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Affiliation(s)
- Tsadok Cohen
- Department of Cell Research and Immunology, Faculty of Life Sciences, Tel Aviv University, Ramat Aviv 69978, Israel
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Scaccianoce S, Mattei V, Del Bianco P, Gizzi C, Sorice M, Hiraiwa M, Misasi R. Hippocampal prosaposin changes during stress: a glucocorticoid-independent event. Hippocampus 2004; 14:275-80. [PMID: 15132426 DOI: 10.1002/hipo.10192] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Several studies indicate that stress can produce remarkable effects on neurotrophic factors. In this regard, hippocampus is the most interesting structure of the brain because of its broad involvement in behavioral and neuroendocrine phenomena. In the present study, we investigated the effect of stress on hippocampal prosaposin, which is known to act as a neurotrophic and neuroprotective factor. Rats subjected to restraint stress (120 min) had a significant and transient reduction of hippocampal, but not hypothalamic, prosaposin full-length protein. Indeed, when this stressful stimulus was applied daily for 3 days, no differences were detected in comparison with naive rats. To investigate the role of glucocorticoids in the stress-induced decrease in hippocampal prosaposin, adrenalectomized and corticosterone-treated rats were studied. The results indicate that adrenalectomized rats behave as intact animals. This finding indicates that the absence of endogenous corticosterone does not prevent a decrease in hippocampal prosaposin. When an increase of corticosterone was achieved through exogenous administration, hippocampal prosaposin concentrations were unchanged in comparison with vehicle-injected (sesame oil) rats. These results led to the conclusion that stress, not via an increase of glucocorticoid hormone, transiently reduces hippocampal prosaposin levels. This phenomenon is followed by rapid recovery of the neurotrophin level, even when the stress stimulus persists.
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Affiliation(s)
- Sergio Scaccianoce
- Dipartimento di Fisiologia Umana e Farmacologia, Vittorio Erspamer, Roma, Italy
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Smiljanic-Georgijev N, Rigat B, Xie B, Wang W, Mahuran DJ. Characterization of the affinity of the G(M2) activator protein for glycolipids by a fluorescence dequenching assay. BIOCHIMICA ET BIOPHYSICA ACTA 1997; 1339:192-202. [PMID: 9187239 DOI: 10.1016/s0167-4838(97)00002-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The G(M2) activator protein is a substrate specific cofactor for degradation of G(M2) ganglioside by lysosomal beta-hexosaminidase A. Mutations in the gene encoding the activator result in the AB-variant form of G(M2) gangliosidosis. The activator protein contains at least three functional elements; a hydrophobic binding pocket, an oligosaccharide binding site(s), and an area that interacts with hexosaminidase A. In this report a fluorescence dequenching assay specific for only the hydrophobic binding pocket is evaluated and optimized. It is shown that various glycolipids inhibit the transport between liposomes of a self-quenching fluorescent lipid probe, octadecylrhodamine, by the activator protein. The level of inhibition produced by each glycolipid is then used to characterize the oligosaccharide-binding specificity of the activator. The fluorescence dequenching assay is also used to evaluate the functionality of a truncated form of the activator protein. Our results indicate that this simple assay can be used to determine structure-function relationships within the normal or mutant forms of the activator. The data suggest that the C-terminus of the activator is required to produce a functional hydrophobic binding pocket.
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Affiliation(s)
- N Smiljanic-Georgijev
- Research Institute, The Hospital for Sick Children, University of Toronto, Ont., Canada
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Hiraiwa M, Taylor EM, Campana WM, Darin SJ, O'Brien JS. Cell death prevention, mitogen-activated protein kinase stimulation, and increased sulfatide concentrations in Schwann cells and oligodendrocytes by prosaposin and prosaptides. Proc Natl Acad Sci U S A 1997; 94:4778-81. [PMID: 9114068 PMCID: PMC20801 DOI: 10.1073/pnas.94.9.4778] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Prosaposin, the precursor of saposins A, B, C, and D, was recently identified as a neurotrophic factor. Herein prosaposin was found to increase sulfatide concentrations in primary and transformed Schwann cells (iSC) and oligodendrocytes (differentiated CG4 cells). Of the four mature saposins, only saposin C was found to increase sulfatide concentrations in these cell types. A similar result was obtained by using peptides (prosaptides) encompassing the neurotrophic sequence located in the saposin C domain. Dose-response curves demonstrated maximal enhancement by saposin C and prosaptides at low nanomolar concentrations (5-10 nM). The increase in sulfatide concentration by a 14-mer prosaptide, TX14(A), in CG4 oligodendrocytes was about 3-fold greater than in primary Schwann cells. A mutant prosaptide with a single amino acid replacement of Asn --> Asp was inactive. Prosaptides did not induce cell proliferation of primary Schwann cells, iSC cells, or CG4 oligodendrocytes but nanomolar concentrations of prosaptides prevented cell death of iSC cells and CG4 oligodendrocytes. Immunoblot analysis demonstrated that phosphorylation of both mitogen-activated protein kinase p-42 and p-44 isoforms were enhanced 3- to 5-fold after 5 min of treatment with prosaptides at concentrations of 1-5 nM. These findings suggest that prosaposin and prosaptides bind to a receptor that initiates signal transduction to promote myelin lipid synthesis and prolong cell survival in both Schwann cells and oligodendrocytes. Prosaposin may function as a myelinotrophic factor in vivo during development and repair of myelinated nerves explaining the deficiency of myelin observed in prosaposin-deficient mice and humans.
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Affiliation(s)
- M Hiraiwa
- Department of Neurosciences, University of California, San Diego, School of Medicine, La Jolla, CA 92093, USA
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