Major glycan structure underlying expression of the Lewis X epitope in the developing brain is O-mannose-linked glycans on phosphacan/RPTPβ.
TL;DR: The results revealed the importance of O-mannosylated glycan chains in the presentation of functional glycan epitopes in the brain.
Abstract: Glycosylation is a major protein modification. Although proteins are glycosylated/further modulated by several glycosyltransferases during trafficking from the endoplasmic reticulum to the Golgi apparatus, a certain glycan epitope has only been detected on a limited number of proteins. Of these glycan epitopes, Lewis X is highly expressed in the early stage of a developing brain and plays important roles in cell-cell interaction. The Lewis X epitope is comprised of a trisaccharide (Galβ1-4 (Fucα1-3) GlcNAc), and a key enzyme for the expression of this epitope is α1,3-fucosyltransferase 9. However, the scaffolding glycan structure responsible for the formation of the Lewis X epitope as well as its major carrier protein has not been fully characterized in the nervous system. Here we showed that the Lewis X epitope was mainly expressed on phosphacan/receptor protein tyrosine phosphatase β (RPTPβ) in the developing mouse brain. Expression of the Lewis X epitope was markedly reduced in β1,4-galactosyltransferase 2 (β4GalT2) gene-deficient mice, which indicated that β4GalT2 is a major galactosyltransferase required for the Lewis X epitope. We also showed that the Lewis X epitope almost disappeared due to the knockout of protein O-mannose β1,2-N-acetylglucosaminyltransferase 1, an N-acetylglucosaminyltransferase essential for the synthesis of O-mannosylated glycans, which indicated that the O-mannosylated glycan is responsible for presenting the Lewis X epitope. Since O-mannosylated glycans on phosphacan/RPTPβ could also present human natural killer-1, another glycan epitope specifically expressed in the nervous system, our results revealed the importance of O-mannosylated glycan chains in the presentation of functional glycan epitopes in the brain.
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TL;DR: In this paper, a microwave-assisted non-reductive release was employed to limit glycan degradation and employed this methodology to analyze O-glycosylation on the human striatum and substantia nigra tissue in Parkinson's disease (PD) and incidental Lewy body disease (ILBD).
Abstract: O-Glycosylation changes in misfolded proteins are of particular interest in understanding neurodegenerative conditions such as Parkinson's disease (PD) and incidental Lewy body disease (ILBD). This work outlines optimizations of a microwave-assisted nonreductive release to limit glycan degradation and employs this methodology to analyze O-glycosylation on the human striatum and substantia nigra tissue in PD, ILBD, and healthy controls, working alongside well-established reductive release approaches. A total of 70 O-glycans were identified, with ILBD presenting significantly decreased levels of mannose-core (p = 0.017) and glucuronylated structures (p = 0.039) in the striatum and PD presenting an increase in sialylation (p < 0.001) and a decrease in sulfation (p = 0.001). Significant increases in sialylation (p = 0.038) in PD were also observed in the substantia nigra. This is the first study to profile the whole nigrostriatal O-glycome in healthy, PD, and ILBD tissues, outlining disease biomarkers alongside benefits of employing orthogonal techniques for O-glycan analysis.
12 citations
TL;DR: The results of these studies suggest that SCI causes a significant alteration in N- and O-linked glycosylation, which was increased in SCI samples compared to shams and non-injured controls.
Abstract: Glycosylation is a fundamental cellular process that has a dramatic impact on the functionality of glycoconjugates such as proteins or lipids and mediates many different biological interactions including cell migration, cellular signaling, and synaptic interactions in the nervous system. In spinal cord injury (SCI), all of these cellular processes are altered, but the potential contributions of glycosylation changes to these alterations has not been thoroughly investigated. We studied the glycosylation of injured spinal cord tissue from rats that received a contusion SCI. The N- and O-linked glycosylation was assessed at 3 and 14 days post-injury (DPI), and compared with uninjured control and time-matched sham spinal tissue. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) and tandem MS (MS/MS) were performed to analyze carbohydrate structures. Results revealed diverse and abundant glycosylation in all groups, with some carbohydrate structures differentially produced in SCI animals compared with uninjured controls and shams. One such change occurred in the abundance of the Sda structure, Neu5Ac-α-(2,3)-[GalNAc-β-(1,4)-]Gal-β-(1,4)-GlcNAc, which was increased in SCI samples compared with shams and non-injured controls. Immunohistochemistry (IHC) and western blot were performed on SCI and sham samples using the CT1 antibody, which recognizes the terminal trisaccharide of Sda with high specificity. Both of these metrics confirmed elevated Sda structure in SCI tissue, where IHC further showed that Sda is expressed mainly by microglia. The results of these studies suggest that SCI causes a significant alteration in N- and O-linked glycosylation.
9 citations
TL;DR: This review evaluates recent information on the identification and functions of specific CSC surface markers, with particular emphasis on colorectal cancers and the screening of drugs to eliminate such cells.
Abstract: Few studies have reported on the analyses of drugs targeting enriched populations of cancer stem cells (CSCs) as a means for identifying potent anti-CSC agents. This review evaluates recent information on the identification and functions of specific CSC surface markers, with particular emphasis on colorectal cancers and the screening of drugs to eliminate such cells. Many of these CSC markers are found commonly expressed on CSCs from different cancer types as well as embryonic stem cells. These markers are often related to hypoxic activation of the WNT/ b-catenin pathway, cyclooxygenase-2/prostaglandin E signalling and their relationship to LGR5. By effectively using drugs that inhibit these pathways to kill the CSC population, or otherwise forcing them out of dormancy into active cell division, cancers should become more susceptible to chemotherapy. Such combinational therapies targeting both CSCs and proliferating tumor cells should greatly improve upon the current basis for treatment.
8 citations
Cites background from "Major glycan structure underlying e..."
...Studies of brain development have shown that expression of CD15/SSEA1 is predominantly associated with O-mannose-linked glycans of the phosphacan/RPTPZ1([159]) and high levels of RPTPZ1 expression have also been reported present in human CRC samples([160])....
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TL;DR: Observations suggest that time‐dependent localization of KSPGs with different sulfation patterns in the song nuclei may underlie song learning in developing male zebra finches.
Abstract: Keratan sulfate proteoglycans (KSPGs) and chondroitin sulfate proteoglycans (CSPGs) consist of a protein core with covalently attached glycosaminoglycan side chain. Although CSPGs are known to regulate the end of the critical period, the role of KSPGs in brain development remains unclear. Young male zebra finches memorise song templates during development. The brain regions that are responsible for song learning, known as song nuclei, are recognized as a suitable model for the study of brain development. To understand the potential role of KSPGs, here we examined the localization of KSs with different degrees of sulfation in the brain of developing male zebra finches. Exclusively in the song nuclei, an increase in expression of 5-D-4-positive (5-D-4(+)) high-sulfated KS started after hatching, and reached a plateau at the end of the sensory period, during which the young bird listens to and memorises the song of an adult tutor. By contrast, weak and ubiquitous expression of BCD-4(+) low-sulfated KS remained unchanged until the end of the sensory period, and first increased in the song nuclei at the end of the sensorimotor period, during which the young bird produces plastic songs. Immunoblot analysis showed that phosphacan was a common core protein of 5-D-4(+) KS and BCD-4(+) KS. Finally, we confirmed that the sulfotransferase responsible for the synthesis of high-sulfated KS was exclusively localised in the song nuclei. Our observations suggest that time-dependent localization of KSPGs with different sulfation patterns in the song nuclei may underlie song learning in developing male zebra finches.
6 citations
Cites background from "Major glycan structure underlying e..."
...In the developing brain, phosphacan plays an important role in cell–cell interaction (Yaji et al., 2015)....
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TL;DR: The expression, molecular structure, and biological roles ofPTPRZ are reviewed, as well as the pathological role of PTPRZ and its application as a diagnostic marker and therapeutic target for gliomas and demyelinating diseases.
Abstract: Gliomas are among the most common tumors of the central nervous system and include highly malignant subtypes, such as glioblastoma, which are associated with poor prognosis. Effective treatments are therefore urgently needed. Despite the recent advances in neuroimaging technologies, differentiating gliomas from other brain diseases such as multiple sclerosis remains challenging in some patients, and often requires invasive brain biopsy. Protein tyrosine phosphatase receptor type Z (PTPRZ) is a heavily glycosylated membrane protein that is highly expressed in the central nervous system. Several reports analyzing mouse tumor models suggest that PTPRZ may have potential as a therapeutic target for gliomas. A soluble cleaved form of PTPRZ (sPTPRZ) in the cerebrospinal fluid is markedly upregulated in glioma patients, making it another promising diagnostic biomarker. Intriguingly, PTPRZ is also involved in the process of remyelination in multiple sclerosis. Indeed, lowered PTPRZ glycosylation by deletion of the glycosyltransferase gene leads to reduced astrogliosis and enhanced remyelination in mouse models of demyelination. Here, we review the expression, molecular structure, and biological roles of PTPRZ. We also discuss glioma and demyelinating diseases, as well as the pathological role of PTPRZ and its application as a diagnostic marker and therapeutic target.
6 citations
References
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TL;DR: Three transformed lines of simian cells were established and found to contain T antigen; retain complete permissiveness for lytic growth of SV40; support the replication of tsA209 virus at 40 degrees C; and support the replicate of pure populations of SV 40 mutants with deletions in the early region.
2,445 citations
"Major glycan structure underlying e..." refers methods in this paper
...COS-1 cells were purchased from American Type Culture Collection (ATCC CRL-1650) (Gluzman 1981)....
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TL;DR: This review discusses the increasingly sophisticated molecular mechanisms being discovered by which mammalian glycosylation governs physiology and contributes to disease.
2,376 citations
"Major glycan structure underlying e..." refers background in this paper
...Moreover, these "specific glycosylations" have been shown to determine the functionality of the carrier glycoproteins (Kleene and Schachner 2004; Ohtsubo and Marth 2006)....
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TL;DR: It is concluded that the majority of sequon containing proteins will be found to be glycosylated and that more than half of all proteins are glycoproteins.
1,756 citations
"Major glycan structure underlying e..." refers background in this paper
...Glycosylation is one of the most frequent post-translational modifications of proteins (Apweiler et al. 1999)....
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TL;DR: It is suggested that interference in O-mannosyl glycosylation is a new pathomechanism for muscular dystrophy as well as neuronal migration disorder.
685 citations
"Major glycan structure underlying e..." refers background or methods in this paper
...…known to be biosynthesized by the first enzyme POMT (Beltran-Valero de Bernabe et al. 2002), and N-acetylglucosamine at O ndokuz M ayis U niversity on N ovem ber 12, 2014 http://glycob.oxfordjournals.org/ D ow nloaded from (GlcNAc) could be transferred to O-mannose by POMGnT1 (Yoshida et al. 2001)....
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...1997) and was synthesized by protein O-mannosyl transferase 1 (POMT1), POMT2, and protein O-mannose β1,2-N-acetylglucosaminyltransferase 1 (POMGnT1) (Yoshida et al. 2001; Manya et al. 2004)....
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...Mutations in the genes encoding POMT1/2 and POMGnT1 have been shown to cause muscular dystrophies with abnormal -DG glycosylation, designated as Walker-Warburg syndrome and muscle-eye-brain disease, respectively (Yoshida et al. 2001; Beltran-Valero de Bernabe et al. 2002; van Reeuwijk et al. 2005)....
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...…(Siaα2-3Galβ1-4GlcNAcβ1-2Man) was discovered in bovine peripheral nerve α-dystroglycan (α-DG) (Chiba et al. 1997) and was synthesized by protein O-mannosyl transferase 1 (POMT1), POMT2, and protein O-mannose β1,2-N-acetylglucosaminyltransferase 1 (POMGnT1) (Yoshida et al. 2001; Manya et al. 2004)....
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...(GlcNAc) could be transferred to O-mannose by POMGnT1 (Yoshida et al. 2001)....
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TL;DR: Immunohistochemical analysis of muscle from patients with POMT1 mutations corroborated the O-mannosylation defect, as judged by the absence of glycosylation of alpha-dystroglycan.
Abstract: Walker-Warburg syndrome (WWS) is an autosomal recessive developmental disorder characterized by congenital muscular dystrophy and complex brain and eye abnormalities. A similar combination of symptoms is presented by two other human diseases, muscle-eye-brain disease (MEB) and Fukuyama congenital muscular dystrophy (FCMD). Although the genes underlying FCMD (Fukutin) and MEB (POMGnT1) have been cloned, loci for WWS have remained elusive. The protein products of POMGnT1 and Fukutin have both been implicated in protein glycosylation. To unravel the genetic basis of WWS, we first performed a genomewide linkage analysis in 10 consanguineous families with WWS. The results indicated the existence of at least three WWS loci. Subsequently, we adopted a candidate-gene approach in combination with homozygosity mapping in 15 consanguineous families with WWS. Candidate genes were selected on the basis of the role of the FCMD and MEB genes. Since POMGnT1 encodes an O-mannoside N-acetylglucosaminyltransferase, we analyzed the possible implication of O-mannosyl glycan synthesis in WWS. Analysis of the locus for O-mannosyltransferase 1 (POMT1) revealed homozygosity in 5 of 15 families. Sequencing of the POMT1 gene revealed mutations in 6 of the 30 unrelated patients with WWS. Of the five mutations identified, two are nonsense mutations, two are frameshift mutations, and one is a missense mutation. Immunohistochemical analysis of muscle from patients with POMT1 mutations corroborated the O-mannosylation defect, as judged by the absence of glycosylation of α-dystroglycan. The implication of O-mannosylation in MEB and WWS suggests new lines of study in understanding the molecular basis of neuronal migration.
645 citations
"Major glycan structure underlying e..." refers background in this paper
...Mutations in the genes encoding POMT1/2 and POMGnT1 have been shown to cause muscular dystrophies with abnormal -DG glycosylation, designated as Walker-Warburg syndrome and muscle-eye-brain disease, respectively (Yoshida et al. 2001; Beltran-Valero de Bernabe et al. 2002; van Reeuwijk et al. 2005)....
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...O-mannosyl glycans are known to be biosynthesized by the first enzyme POMT (Beltran-Valero de Bernabe et al. 2002), and N-acetylglucosamine at O ndokuz M ayis U niversity on N ovem ber 12, 2014 http://glycob.oxfordjournals.org/ D ow nloaded from (GlcNAc) could be transferred to O-mannose by POMGnT1…...
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