Background
Topiroxostat, an inhibitor of xanthine oxidoreductase (XOR) was shown to reduce urinary albumin excretion of hyperuricemic patients with chronic kidney disease. However, its pharmacological mechanism is not well understood. In this study, we examined the effects of topiroxostat on glomerular podocytes. Podocyte is characterized by foot process and a unique cell-cell junction slit diaphragm functioning as a final barrier to prevent proteinuria.

Methods
The effects of topiroxostat on the expressions of podocyte functional molecules were analysed in db/db mice, a diabetic nephropathy model, anti-nephrin antibody-induced rat podocyte injury model and cultured podocytes treated with adriamycin.

Results
Topiroxostat treatment ameliorated albuminuria in db/db mice. The expression of desmin, a podocyte injury marker was increased, and nephrin and podocin, key molecules of slit diaphragm, and podoplanin, an essential molecule in maintaining foot process were downregulated in db/db mice. Topiroxostat treatment prevented the alterations in the expressions of these molecules in db/db mice. XOR activity in kidney was increased in rats with anti-nephrin antibody-induced podocyte injury. Topiroxostat treatment reduced XOR activity and restored the decreased expression of nephrin, podocin and podoplanin in the podocyte injury. Furthermore, topiroxostat enhanced the expression of podoplanin in injured human cultured podocytes.

Conclusions
Podocyte injury was evident in db/db mice. Topiroxostat ameliorated albuminuria in diabetic nephropathy model by preventing podocyte injury. Increase of XOR activity in kidney contributes to development of podocyte injury caused by stimulation to slit diaphragm. Topiroxostat has an effect to stabilize slit diaphragm and foot processes by inhibiting the reduction of nephrin, podocin and podoplanin.

DOI： 10.1016/j.nefroe.2021.11.007

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

Ephrin-B1 plays a critical role at slit diaphragm. Partitioning-defective (Par)-6 is down-regulated in podocyte of ephrin-B1 knockout mouse, suggesting that Par-6 is associated with ephrin-B1. Par polarity complex, consisting of Par-6, Par-3, and atypical protein kinase C, is essential for tight junction formation. In this study, the expression of Par-6 was analyzed in the normal and nephrotic syndrome model rats, and the molecular association of Par-6, Par-3, ephrin-B1, and nephrin was assessed with the human embryonic kidney 293 cell expression system. Par-6 was concentrated at slit diaphragm. Par 6 interacted with ephrin-B1 but not with nephrin, and Par-3 interacted with nephrin but not with ephrin-B1. The complexes of Par-6-ephrin-B1 and Par-3-nephrin were linked via extracellular sites of ephrin-B1 and nephrin. The Par-6-ephrin-B1 complex was delinked from the Par-3-nephrin complex, and Par-6 and ephrin-B1 were clearly down-regulated already at early phase of nephrotic model. The alteration of Par-6/ephrin-B1 advanced that of Par-3/nephrin. Stimulation to nephrin phosphorylated not only nephrin but also ephrin-B1, and consequently inhibited the interaction between ephrin-B1 and Par-6. Par-6 appeared at presumptive podocyte of early developmental stage and moved to basal area at capillary loop stage to participate in slit diaphragm formation at the final stage. Par-6-ephrin-B1 interaction is crucial for formation and maintenance of slit diaphragm of podocyte.

DOI： 10.1016/j.ajpath.2019.10.015

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Society of Nephrology  

Background B-type ephrins are membrane-bound proteins that maintain tissue function in several organs. We previously reported that ephrin-B1 is localized at the slit diaphragm of glomerular podocytes. However, the function of ephrin-B1 at this location is unclear. Methods We analyzed the phenotype of podocyte-specific ephrin-B1 knockout mice and assessed the molecular association of ephrin-B1 and nephrin, a key molecule of the slit diaphragm, in HEK293 cells and rats with anti-nephrin antibody-induced nephropathy. Results Compared with controls, ephrin-B1 conditional knockoutmice displayed altered podocytemorphology, disarrangement of the slit diaphragm molecules, and proteinuria. Ephrin-B1 expressed in HEK293 cells immunoprecipitated with nephrin, which required the basal regions of the extracellular domains of both proteins. Treatment of cells with an anti-nephrin antibody promoted the phosphorylation of nephrin and ephrin-B1. However, phosphorylation of ephrin-B1 did not occur in cells expressing amutant nephrin lacking the ephrin-B1 binding site or in cells treated with an Src kinase inhibitor. The phosphorylation of ephrin-B1 enhanced the phosphorylation of nephrin and promoted the phosphorylation of c-Jun N-terminal kinase (JNK), which was required for ephrin-B1- promoted cell motility in wound-healing assays. Notably, phosphorylated JNK was detected in the glomeruli of control mice but not ephrin-B1 conditional knockout mice. In rats, the phosphorylation of ephrin-B1, JNK, and nephrin occurred in the early phase (24 hours) of anti-nephrin antibody-induced nephropathy. Conclusions Through interactions with nephrin, ephrin-B1 maintains the structure and barrier function of the slit diaphragm. Moreover, phosphorylation of ephrin-B1 and, consequently, JNK are involved in the development of podocyte injury.

DOI： 10.1681/ASN.2017090993

Scopus

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

14-3-3 proteins are a ubiquitously expressed family of adaptor proteins. Despite exhibiting high sequence homology, several 14-3-3 isoforms have isoform-specific binding partners and roles. We reported that 14-3-3β interacts with FKBP12 and synaptopodin to maintain the structure of actin fibers in podocytes. However, the precise localization and differential role of 14-3-3 isoforms in kidneys are unclear. Herein, we showed that 14-3-3β in glomeruli was restricted in podocytes, and 14-3-3σ in glomeruli was expressed in podocytes and mesangial cells. Although 14-3-3β was dominantly co-localized with FKBP12 in the foot processes, a part of 14-3-3β was co-localized with Par3 at the slit diaphragm. 14-3-3β interacted with Par3, and FKBP12 bound to 14-3-3β competitively with Par3. Deletion of 14-3-3β enhanced the interaction of Par3 with Par6 in podocytes. Gene silencing for 14-3-3β altered the structure of actin fibers and process formation. 14-3-3β and synaptopodin expression was decreased in podocyte injury models. In contrast, 14-3-3σ in podocytes was expressed in the primary processes. 14-3-3σ interacted with vimentin but not with the actin-associated proteins FKBP12 and synaptopodin. Gene silencing for 14-3-3σ altered the structure of vimentin fibers and process formation. 14-3-3σ and vimentin expression was increased in the early phase of podocyte injury models but was decreased in the late stage. Together, the localization of 14-3-3β at actin cytoskeleton plays a role in maintaining the foot processes and the Par complex in podocytes. In contrast, 14-3-3σ at vimentin cytoskeleton is essential for maintaining primary processes.

DOI： 10.1096/fj.202300865R

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

NeXtProt is a web-based protein knowledge platform that supports research on human proteins. NeXtProt (release 2015-04-28) lists 20,060 proteins, among them, 3373 canonical proteins (16.8%) lack credible experimental evidence at protein level (PE2:PE5). Therefore, they are considered as "missing proteins". A comprehensive bio-informatic workflow has been proposed to analyze these "missing" proteins. The aims of current study were to analyze physicochemical properties, existence and distribution of the tryptic cleavage sites, and to pinpoint the signature peptides of the missing proteins. Our findings showed that 23.7% of missing proteins were hydrophobic proteins possessing transmembrane domains (TMD). Also, forty missing entries generate tryptic peptides were either out of mass detection range (>30 aa) or mapped to different proteins (<9 aa). Additionally, 21% of missing entries didn't generate any unique tryptic peptides. In silico endopeptidase combination strategy increased the possibility of missing proteins identification. Coherently, using both mature protein database and signal peptidome database could be a promising option to identify some missing proteins by targeting their unique N-terminal tryptic peptide from mature protein database and or C-terminus tryptic peptide from signal peptidome database. In conclusion, Identification of missing protein requires additional consideration during sample preparation, extraction, digestion and data analysis to increase its incidence of identification. (C) 2016 Published by Elsevier B.V.

DOI： 10.1016/j.jprot.2016.08.005

Web of Science

researchmap

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：SAGE PUBLICATIONS LTD  

Nephrin, a major intercellular junction (ICJ) molecule of mammalian podocytes in the renal glomerulus, is absent in the avian genome. We hypothesized that birds use ICJ molecules other than nephrin in their podocytes. Therefore, in the present study, we examined the possible involvement of adherens junction (AJ) proteins in the ICJs of avian podocytes. We found the AJ proteins N-cadherin and - and -catenins in podocytes of quail and chickens but not in those of rats, pigs or humans. The AJ proteins were prominent in avian glomerulus-rich fractions in immunoblot analyses, and in immunofluorescence microscopy analyses, they were localized along glomerular capillary walls appearing in at least two staining patterns: weakly diffuse and distinctly granular. Immunoelectron microscopy demonstrated that the significant accumulation of immunogold particles for the AJ proteins were especially evident in avian slit diaphragms and AJs. Furthermore, N-cadherin was found to be expressed in all nephron cells in the early developmental stage but became confined to podocytes during maturation. These results indicate that avian slit diaphragms clearly express AJ proteins as compared with that in the mammalwhere AJ proteins are suppressed to an extremely low leveland that avian podocytes are interconnected by AJs per se in addition to slit diaphragms.

DOI： 10.1369/0022155415611708

Web of Science

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-BLACKWELL  

Urine has evolved as one of the most important biofluids in clinical proteomics due to its noninvasive sampling and its stability. Yet, it is used in clinical diagnostics of several disorders by detecting changes in its components including urinary protein/polypeptide profile. Despite the fact that majority of proteins detected in urine are primarily originated from the urogenital (UG) tract, determining its precise source within the UG tract remains elusive. In this article, we performed a comprehensive analysis of ureter proteome to assemble the first unbiased ureter dataset. Next, we compared these data to urine, urinary exosome, and kidney mass spectrometric datasets. Our result concluded that among 2217 nonredundant ureter proteins, 751 protein candidates (33.8%) were detected in urine as urinary protein/polypeptide or exosomal protein. On the other hand, comparing ureter protein hits (48) that are not shown in corresponding databases to urinary bladder and prostate human protein atlas databases pinpointed 21 proteins that might be unique to ureter tissue. In conclusion, this finding offers future perspectives for possible identification of ureter disease-associated biomarkers such as ureter carcinoma. In addition, the ureter proteomic dataset published in this article will provide a valuable resource for researchers working in the field of urology and urine biomarker discovery. All MS data have been deposited in the ProteomeXchange with identifier PXD002620 ().

DOI： 10.1002/pmic.201500214

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier Inc.  

Human glomeruli with intermediate (i-GS) and advanced (GS) sclerotic lesions as well as the normal control (Nor) were captured from laser microdissection, digested by trypsin and subjected to shotgun LC-MS/MS analysis (LTQ-Orbitrap XL). The label-free quantification was performed using the Normalized Spectral Index (SIN) to assess the relative molar concentration of each protein identified in a sample. All the experimental data are shown in this article. The data is associated to the research article submitted to Journal of Proteomics [1].

DOI： 10.1016/j.dib.2015.05.013

Scopus

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

OFFGEL fractionation of mouse kidney protein lysate and its tryptic peptide digest has been examined in this study for better understanding the differences between protein and peptide fractionation methods and attaining maximum recruitment of this modern methodology for in-depth proteomic analysis. With the same initial protein/peptide load for both fractionation methods, protein OFFGEL fractionation showed a preponderance in terms of protein identification, fractionation efficiency, and focusing resolution, while peptide OFF GEL was better in recovery, number of peptide matches, and protein coverage. This result suggests that the protein fractionation method is more suitable for shotgun analysis while peptide fractionation suits well quantitative peptide analysis [isobaric tags for relative and absolute quantitation (iTRAQ) or tandem mass tags (TMT)]. Taken together, utilization of the advantages of both fractionation approaches could be attained by coupling both methods to be applied on complex biological tissue. A typical result is shown in this article by identification of 8262 confident proteins of whole mouse kidney under stringent condition. We therefore fractionation as an effective and efficient addition to both label-free and quantitative label proteomics workflow.

DOI： 10.1021/acs.analchem.5b01911

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-BLACKWELL  

Formalin-fixed paraffin-embedded (FFPE) tissue is considered as an appropriate alternative to frozen/fresh tissue for proteomic analysis. Here we study formalin-induced alternations on a proteome-wide level. We compared LC-MS/MS data of FFPE and frozen human kidney tissues by two methods. First, clustering analysis revealed that the biological variation is higher than the variation introduced by the two sample processing techniques and clusters formed in accordance with the biological tissue origin and not with the sample preservation method. Second, we combined open modification search and spectral counting to find modifications that are more abundant in FFPE samples compared to frozen samples. This analysis revealed lysine methylation (+14 Da) as the most frequent modification induced by FFPE preservation. We also detected a slight increase in methylene (+12 Da) and methylol (+30 Da) adducts as well as a putative modification of +58 Da, but they contribute less to the overall modification count. Subsequent SEQUEST analysis and X!Tandem searches of different datasets confirmed these trends. However, the modifications due to FFPE sample processing are a minor disturbance affecting 2-6% of all peptide-spectrum matches and the peptides lists identified in FFPE and frozen tissues are still highly similar.

DOI： 10.1002/pmic.201400454

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

Since glomerular sclerosis frequently accompanies various glomerular diseases at the end stages, it is challenging to differentiate ubiquitous biological processes underlying this pathology from those critically involved in specific diseases. Furthermore, in-depth proteomic profile of human glomerular sclerosis remains limited. In this study, human glomeruli with intermediate (i-GS) and advanced (GS) sclerotic lesions, which were excluded from specific renal diseases and assumed to be aging-related, were laser captured from macroscopically normal cortex distant from urological carcinoma, and subjected to label-free quantitative proteomic analysis. We explicate an evident increase of membrane attack complex in i-GS and GS with an up-going tendency, which is accompanied by increasing of inhibitory regulators of alternative and terminal pathways. GO annotation and IPA pathway analysis agree to these results. Proteomic findings are validated by immunohistochemical studies which indicate that alternative and terminal pathways are positively involved in the glomerular sclerosis seen in distinct renal diseases. Furthermore, proteomic analysis also demonstrates remarkable increases of complement factor B in GS and TGF-beta 1 in both GS and i-GS. Identification of complement factor B implicates that on-site activation of alternative pathway may occur in injured glomeruli and stepwise increase of TGF-beta 1 suggests its contribution to the progression of glomerulosclerosis.
Biological significance
This study provides in-depth quantitative proteornic profiles of human glomeruli with intermediate and advanced sclerotic lesions. It reveals that the over-expression of alternative and terminal pathway components is significantly involved in human glomerulosclerosis seen in distinct renal diseases. Proteomic identification of the increased TGF-beta 1 provides supporting evidence for the role of podocyte apoptosis leading to human glomerulosclerosis. (C) 2015 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jprot.2015.03.024

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：OXFORD UNIV PRESS  

neXtProt (http://www.nextprot.org) is a human protein-centric knowledgebase developed at the SIB Swiss Institute of Bioinformatics. Focused solely on human proteins, neXtProt aims to provide a state of the art resource for the representation of human biology by capturing a wide range of data, precise annotations, fully traceable data provenance and a web interface which enables researchers to find and view information in a comprehensive manner. Since the introductory neXtProt publication, significant advances have been made on three main aspects: the representation of proteomics data, an extended representation of human variants and the development of an advanced search capability built around semantic technologies. These changes are presented in the current neXtProt update.

DOI： 10.1093/nar/gku1178

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER  

Several proteins have been proposed as new urinary biomarkers of kidney injuries, but they are not always capable of identifying the kidney nephron segment that has been injured. Since calbindin 1 protein is exclusively localized in the kidney distal nephron segment, it is presumed that its expression is altered during distal nephron segment injuries, resulting in changes in its urinary excretion.
Calbindin 1 expression in normal rat kidneys was compared with that in the kidneys of rats that had suffered distal nephron segment injuries (unilateral ureteral obstruction [UUO] or anti-glomerular basement membrane glomerulonephritis [anti-GBM GN]) using immunohistochemical examinations and real-time polymerase chain reaction. The urinary calbindin 1 protein concentration of normal rats was also compared with that of anti-GBM GN rats and of cisplatin nephropathy rats using Western blotting. We also compared the kidney and urinary calbindin 1 protein concentrations of normal human subjects with those of proteinuric patients [immunoglobulin (Ig)A nephropathy; IgAN] with distal nephron segment injuries.
Calbindin 1 mRNA expression in the renal cortices and calbindin 1 protein expression in the kidney distal nephron segments were decreased in the UUO and anti-GBM GN rat kidneys. The urinary calbindin 1 protein levels of the anti-GBM GN rats were also markedly decreased, whereas those of the cisplatin nephropathy rats were slightly decreased. The human IgAN patients displayed decreased renal calbindin 1 protein expression in their dilated distal tubules, and some patients displayed decreased urinary calbindin 1 levels.
Since it has been demonstrated that decreased urinary calbindin 1 levels are indicative of decreased calbindin 1 kidney expression due to distal nephron segment injuries, calbindin 1 might be a useful urinary biomarker for identifying distal nephron segment injuries.

DOI： 10.1007/s10157-013-0835-3

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-BLACKWELL  

AimHeparin, a highly sulfated glycosaminoglycan, has been shown to have a renoprotective effect on renal diseases, but its mechanisms remain to be elucidated. In this study, we examined the effect of heparin on podocytes by using primary cultured podocytes positive for podocyte-specific markers including podocin and podocalyxin.
MethodsPodocytes were cultured from highly purified glomeruli isolated by the method with renal perfusion with magnetic beads and digestion of collagenase. Podocyte-specific gene expressions and proteins were examined by real-time polymerase chain reaction (PCR), Western blotting and immunofluorescence microscopy.
ResultsReal-time PCR showed that addition of heparin to the culture media significantly upregulated most of the podocyte-specific genes in a dose-dependent and time-dependent manner. Western blotting showed a marked increase in protein levels of nephrin and podocin. Podocin localization at cell-cell contact sites became conspicuous in the presence of heparin. The effect of heparin was observed even in culture media deprived of bovine foetal serum. Heparan sulfate, less sulfated than heparin, and hyaluronan did not show such effects, but sulfated dextran did markedly.
ConclusionHeparin acts on cultured podocytes to increase podocyte-specific gene expressions. A high degree of sulfation is crucial for the effect of heparin.
Summary at a Glance This study characterises the rapid downregulation of podocyte specific genes in primary cultures of podocytes isolated from rat glomeruli. However, the addition of heparin sulphate promoted nephrin and podocin expression in cultured podocytes, which may explain the protective effect of heparin sulphate in models of proteinuria and glomerulosclerosis.

DOI： 10.1111/nep.12207

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Performing a comprehensive nonbiased proteome analysis is an extraordinary challenge due to sample complexity and wide dynamic range, especially in eukaryotic tissues. Thus, prefractionation steps conducted prior to mass spectrometric analysis are critically important to reduce complex biological matrices and allow in-depth analysis. Here we demonstrated the use of OFFGel prefractionation to identify more low abundant and hydrophobic proteins than in a nonfractionated sample. Moreover, OFFGel prefractionation of a kidney protein sample was able to unveil protein functional relevance by detecting PTMs, especially when prefractionation was augmented with a targeted enrichment strategy such as TiO2 phospho-enrichment. The OFFGel-TiO2 combination used in this study was comparable to other global phosphoproteomics approaches (SCX-TiO2 ERLIC-TiO2, or HILIC-TiO2). The detailed mouse kidney proteome with the phosphopeptide enrichment presented here serves as a useful platform for a better understanding of how the renal protein modification machinery works and, ultimately, will contribute to our understanding of pathological processes as well as normal physiological renal functions.

DOI： 10.1021/pr401122m

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer-Verlag Tokyo  

DOI： 10.1007/s10157-013-0846-0

Scopus

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

Gel- based proteomics is one of the most versatile methods for fractionating protein complexes. Among these methods, two dimensional- polyacrylamide gel electrophoresis (2-DE) represents a mainstay orthogonal approach, which is popularly used to simultaneously fractionate, identify, and quantify proteins when coupled with mass spectrometric identification or other immunological tests. Although 2-DE was first introduced more than three decades ago, several challenges and limitations to its utility still exist. This review discusses the principles of 2-DE as well as both recent methodological advances and new applications.

DOI： 10.1186/1559-0275-11-16,

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER  

Vascular endothelial cells (VECs) play crucial roles in physiological and pathologic conditions in tissues and organs. Most of these roles are related to VEC plasma membrane proteins. In the kidney, VECs are closely associated with structures and functions; however, plasma membrane proteins in kidney VECs remain to be fully elucidated.
Rat kidneys were perfused with cationic colloidal silica nanoparticles (CCSN) to label the VEC plasma membrane. The CCSN-labeled plasma membrane fraction was collected by gradient ultracentrifugation. The VEC plasma membrane or whole-kidney lysate proteins were separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis and digested with trypsin in gels for liquid chromatography-tandem mass spectrometry. Enrichment analysis was then performed.
The VEC plasma membrane proteins were purified by the CCSN method with high yield (approximately 20 mu g from 1 g of rat kidney). By Mascot search, 582 proteins were identified in the VEC plasma membrane fraction, and 1,205 proteins were identified in the kidney lysate. In addition to 16 VEC marker proteins such as integrin beta-1 and intercellular adhesion molecule-2 (ICAM-2), 8 novel proteins such as Deltex 3-like protein and phosphatidylinositol binding clathrin assembly protein (PICALM) were identified. As expected, many key functions of plasma membranes in general and of endothelial cells in particular (i.e., leukocyte adhesion) were significantly overrepresented in the proteome of CCSN-labeled kidney VEC fraction.
The CCSN method is a reliable technique for isolation of VEC plasma membrane from the kidney, and proteomic analysis followed by bioinformatics revealed the characteristics of in vivo VECs in the kidney.

DOI： 10.1007/s10157-012-0708-1

Web of Science

researchmap

DOI： 10.1186/1477-5956-11-13

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

European community acquired methicillin resistant Staphylococcus aureus (CA-MRSA) clone remains a striking pathogenic clone spreading in European and Mediterranean countries. Since analysis of the secretome produced from this clone by proteomics could provide a comprehensive picture of both core exoproteins as well as virulence factors, we applied two proteomic approaches, pre-fractionation of proteins on SDS-PAGE followed by in-gel trypsin digestion, and in-solution trypsin-digestion followed by off-line SCX fractionation, both of which were coupled with LC-MS/MS analyses. A total of 174 distinct proteins were identified with a high-confidence. Functional classification of these identified proteins resulted in16.09% of protein synthesis, 13.79% of virulence, 6.89% of toxin, and 17.24% of unknown function. Prediction of their cellular localizations revealed 18.39% in extracellular space, 36.20% in cytoplasm, 5.17% in cytoplasmic membranes, 6.89% in cell wall, 1.14% in multiple localizations, and 32.18% in unknown localization. Among them, 52% proteins were predicted to be secreted through signal peptide-independent pathways. Most notably, the expression of some proteins such as enterotoxins U and B were identified for the first time in this clone. © 2012 Elsevier Inc.

DOI： 10.1016/j.peptides.2012.06.011

Scopus

PubMed

researchmap

DOI： 10.1002/prca.201200016

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：BIOMED CENTRAL LTD  

Background: Most of the current proteomic researches focus on proteome alteration due to pathological disorders (i.e.: colorectal cancer) rather than normal healthy state when mentioning colon. As a result, there are lacks of information regarding normal whole tissue-colon proteome.
Results: We report here a detailed murine (mouse) whole tissue-colon protein reference dataset composed of 1237 confident protein (FDR < 2) with comprehensive insight on its peptide properties, cellular and subcellular localization, functional network GO annotation analysis, and its relative abundances. The presented dataset includes wide spectra of pI and Mw ranged from 3-12 and 4-600 KDa, respectively. Gravy index scoring predicted 19.5% membranous and 80.5% globularly located proteins. GO hierarchies and functional network analysis illustrated proteins function together with their relevance and implication of several candidates in malignancy such as Mitogen-activated protein kinase (Mapk8, 9) in colorectal cancer, Fibroblast growth factor receptor (Fgfr 2), Glutathione S-transferase (Gstp1) in prostate cancer, and Cell division control protein (Cdc42), Ras-related protein (Rac1,2) in pancreatic cancer. Protein abundances calculated with 3 different algorithms (NSAF, PAF and emPAI) provide a relative quantification under normal condition as guidance.
Conclusions: This highly confidence colon proteome catalogue will not only serve as a useful reference for further experiments characterizing differentially expressed proteins induced from diseased conditions, but also will aid in better understanding the ontology and functional absorptive mechanism of the colon as well.

DOI： 10.1186/1756-0381-5-11

Web of Science

researchmap

Language：Japanese   Publisher：Japanese Proteomics Society (Japan Human Proteome Organisation)  

DOI： 10.14889/jhupo.2012.0.91.0

CiNii Article

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

Eicosapentaenoic Acid (EPA) is an omega-3 fatty acid (polyunsaturated fatty acid) that has pleiotropic effects as hypolipidemic and anti-inflammatory actions. Podocytes injury in the renal glomeruli has been proposed as the crucial mechanism in the development of focal segmental glomerulosclerosis or nephrosis. The effect of EPA on Puromycin aminonucleoside (PAN) induced nephrosis was tested. EPA was administered daily for 28 days at a dose of 1 g kg-1 b.wt. then PAN was injected intravenously at a dose of 6 mg/100 g of body weight followed by EPA for 6 days. PAN nephrosis induced increase in proteinuria, lipid profiles, podocytes proteins expression and immunolocalization. EPA induced decrease in proteinuria and lipid profiles induced by PAN nephrosis. Also, EPA induced significant down-regulation in expression of connexin 43 and synaptopodin. Moreover, EPA induced 50% decrease in glomerular cell adhesion induced by PAN nephrosis. Immunoflerusecnce shows expression of desmin and connexin 43 in rat glomeruli that increased by PAN and decreased by EPA. These findings collectively showed that EPA has reno-protective effect during inflammation. © 2012 Academic Journals Inc.

DOI： 10.3923/ajb.2012.16.26

Scopus

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

In the field of bottom-up proteomics, heavy contamination of human keratins could hinder the comprehensive protein identification, especially for the detection of low abundance proteins. In this study, we examined the keratin contamination in the four major experimental procedures in gel-based proteomic analysis including gel preparation, gel electrophoresis, gel staining, and in-gel digestion. We found that in-gel digestion procedure might be of importance corresponding to keratin contaminants compared to the other three ones. The human keratin contamination was reduced significantly by using an electrostatic eliminator during in-gel digestion, suggesting that static electricity built up on insulated experimental materials might be one of the essential causes of keratin contamination. We herein proposed a series of methods for improving experimental conditions and sample treatment in order to minimize the keratin contamination in an economical and practical way. (C) 2011 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jprot.2011.03.001

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER  

Tight junctions are the main intercellular junctions of podocytes of the renal glomerulus under nephrotic conditions. Their requisite components, claudins, still remain to be identified. We have measured the mRNA levels of claudin subtypes by quantitative real-time PCR using isolated rat glomeruli. Claudin-5 was found to be expressed most abundantly in glomeruli. Mass spectrometric analysis of membrane preparation from isolated glomeruli also confirmed only claudin-5 expression without any detection of other claudin subtypes. In situ hybridization and immunolocalization studies revealed that claudin-5 was localized mainly in glomeruli where podocytes were the only cells expressing claudin-5. Claudin-5 protein was observed on the entire surface of podocytes including apical and basal domains of the plasma membrane in the normal condition and was inclined to be concentrated on tight junctions in puromycin aminonucleoside nephrosis. Total protein levels of claudin-5 in isolated glomeruli were not significantly upregulated in the nephrosis. These findings suggest that claudin-5 is a main claudin expressed in podocytes and that the formation of tight junctions in the nephrosis may be due to local recruitment of claudin-5 rather than due to total upregulation of the claudin protein levels.

DOI： 10.1007/s00441-010-1117-y

Web of Science

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

We have developed an easy-to use methodology for refining large extensible markup language (XML) - based proteomics dataset with a high stringent and simple approach using VBA- coded plug-in. A methodology we term it (All and None). Selections of targeted candidates differentially significant between compared groups were selected based on its appearance or absence followed by peptide screening with a novel and simple approach. By testing the reliability and efficiency of this method, All and None was confirmed to be an applicable process for initial screening of biological biomarkers in complex specimens and tissue extract. © 2011 Magdeldin S, et al.

DOI： 10.4172/jpb.1000178

Scopus

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Aquaporin (AQP) family plays a pivotal role in fluid secretion and absorption especially in the digestive system and secretory glands Within this family AQP8 was reported to be widely expressed in the epithelia of the digestive tract, liver, and pancreas In two parallel experimental platforms with different analytical and comparative approaches, in gel tryptic digestion with macro-embedded spreadsheet analysis and in-solution tryptic digestion with LC MS alignment based approach we compared wild type and AQP8 knockout mice colon proteomes Shared result between both experiments revealed down-regulation of alpha-amylase 2 in AQP8-deleted mice model Verification on both transcriptional and translational levels confirmed the involvement of AQP8 in alpha-amylase 2 regulation Given the profound role of AQP8 as a water and solutes transporter, it might be important in modulating a-amylase 2 synthesis by colonic epithelial cells as well Here, we also proved the capability of our coupled approaches for selecting the most reliable and significant candidates, an applicable process for initial screening of biological biomarkers in complex specimens and tissue extracts

DOI： 10.1021/pr100789v

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

Aquaporin (AQP) family plays a fundamental role in transmembrane water and small solutes movement. Within this family, aquaporin 8 (AQP8), showed to be widely distributed in the digestive system especially colon. To investigate the possible protein alterations involved in AQP8 regulation and trafficking, we extensively compared between wild type and AQP8 knockout mouse colon using semi-quantitative fluorescence- stained two dimensional gel electrophoresis (2-DE) coupled with nano LC-Ms/Ms. Our analysis revealed identification and regulation of 21 proteins, most notably, actin-related family which suggests its possible involvement in regulating AQP8 secretory vesicles migration to be integrated as a cell membrane protein. (C) 2010 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jprot.2010.06.010

Web of Science

researchmap

DOI： 10.1093/ndt/gfp697

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：GENERAL PHYSIOL AND BIOPHYSICS  

In order to investigate the effects of dietary supplementation rich in omega 3 and omega 6 fatty acids, we set up an experiment of twenty four C57BL/6J male mice segregated into 3 groups: normal diet (ND), omega 3 polyunsaturated fatty acid (n-3 PUFA,) and omega 6 (n-6 PUFA). At the end of the experiment that lasted for I month, food consumption of ND and n-3 PUFA were similar while it decreased in n-6 PUFA group. Total cholesterol, triglycerides, free fatty acids, and phospholipids profiles were increased in n-6 PUFA. LDL decreased in n-3 PUFA while increased in n-6 PUFA fed mice comparing to control group. On the other hand, there was no difference between treatments in HDL and glucose levels. Expression of leptin (ob) gene transcripts in epididymal fat were significantly elevated in n-6 PUFA mice compared to ND and n-3 PUFA groups while hypothalamic ob receptor A (obRa) mRNA did not changed in response to diet regimes. Transmission and scanning electron microscopy showed different degrees in fatty changes in the liver of both PUFA groups including lipid droplet infiltration and Ito cells with over accumulated lipids. In conclusion, under PUFA dietary supplementation, the hyperlipidemic status and elevated ob expression of n-6 PUFA but not n-3 PUFA fed mice suggests altered lipid metabolism between PUFA groups and/or different endocrine involvement. Moreover, the coincidently structural changes observed in liver of this group direct us to call for further studies to investigate the anti-obesity effect and safety of these PUFA under high supplementation condition.

DOI： 10.4149/gpb_2009_03_266

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

BACKGROUND: It is generally admitted that ABO(H) blood group antigens are linked to lipids and proteins. Although glycolipids carrying ABO antigens have been well characterized in human kidneys, glycoproteins carrying ABO antigens are largely unknown, and their molecular properties remain to be elucidated. METHODS: All the blood group A antigen-linked proteins in human kidney could be solubilized and captured on immobilized Helix pomatia lectin that recognizes A antigens. These proteins were separated on SDS-PAGE gels. The gel pieces containing protein bands immunoreactive with anti-A antibody were excised, in-gel digested with trypsin, and analyzed by nanoLC tandem mass spectrometer. Protein candidates that carry ABO antigens were confirmed by immunoprecipitation and double-labeled immunofluorescense microscopy. RESULTS: All the glycoproteins carrying ABO antigens were found to be Asn-linked glycoproteins, and presented as multiple bands on SDS-PAGE with molecular masses ranging from 60 to 270 kDa. The protein bands were subjected for mass spectrometric analysis, which identified 121 distinct proteins with high confidence. Of the identified proteins, 55 N-glycosylated, membrane proteins were selected as glycoprotein candidates that carry ABO antigens. Among them, most abundantly expressed proteins as estimated by the number of peptide matches in the MS spectrometric analysis, such as platelet endothelial cell adhesion molecule 1, plasmalemmal vesicle-associated protein, and von Willebrand factor, were further characterized. CONCLUSIONS: Several glycoproteins were identified that represented major glycoproteins carrying ABO antigens in the human kidney, which exhibited distinct features in localization to most of vascular endothelial cells.

DOI： 10.1097/TP.0b013e31819e0054

PubMed

researchmap

Language：Japanese   Publisher：(一社)日本腎臓学会  

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：KARGER  

Background/Aims: Mesangial cells bear the tensional forces generated in the glomerular capillary wall. Not only mesangial cells per se, but also their intercellular junctions should be physically stable against the tensional forces; this prompted the search for actin filament- reinforced adherens junctions of mesangial cells. We previously reported alpha- and beta-catenins localized at the cell-cell contact sites of mesangial cells in the rat. Classical cadherin expressed by mesangial cells, however, remains to be elucidated. Methods: Expression of classical cadherins, especially N-cadherin, was examined in rat glomeruli by ribonuclease protection assay, Western blot analysis and immunofluorescence and immuno-electron microscopy. Results: Ribonuclease protection assay detected significant expression of N-cadherin in rat glomeruli. Western blot analysis showed that rabbit and murine antibodies against N-cadherin reacted with a specific band in isolated glomeruli. Immunofluorescence microscopy revealed that both antibodies reacted only with the mesangium in glomeruli. Immunoelectron microscopy demonstrated that the immunogold particles for N-cadherin were found predominantly at cell-cell contact sites of mesangial cells where actin filaments concentrated. Conclusion: N-cadherin interconnects mesangial cells, suggesting that the cadherin-catenin-actin filament system in the mesangium may play a role in the counteraction of the hydraulic pressure gradient across the capillary wall. Copyright (C) 2009 S. Karger AG, Basel

DOI： 10.1159/000224797

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER PHYSIOLOGICAL SOC  

Tight junctions rarely exist in podocytes of the normal renal glomerulus, whereas they are the main intercellular junctions of podocytes in nephrosis and in the early stage of development. Claudins have been identified as tight junction-specific integral membrane proteins. Those of podocytes, however, remain to be elucidated. In the present study, we investigated the expression and localization of claudin-6 in the rat kidney, especially in podocytes. Western blot analysis and RT-PCR revealed that the neonatal kidney expressed much higher levels of claudin-6 than the adult kidney. Immunofluorescence microscopy showed intense claudin-6 staining in most of the tubules and glomeruli in neonates. The staining in tubules declined distinctly in adults, whereas staining in glomeruli was well preserved during development. Claudin-6 in glomeruli was distributed along the glomerular capillary wall and colocalized with zonula occludens-1. The staining became conspicuous after kidney perfusion with protamine sulfate (PS) to increase tight junctions in podocytes. Immunoelectron microscopy showed that immunogold particles for claudin-6 were accumulated at close cell-cell contact sites of podocytes in PS-perfused kidneys, whereas a very limited number of immunogold particles were detected, mainly on the basal cell membrane and occasionally at the slit diaphragm and close cell-cell contact sites in normal control kidneys. In puromycin aminonucleoside nephrosis, immunogold particles were also found mainly at cell-contact sites of podocytes. These findings indicate that claudin-6 is a transmembrane protein of tight junctions in podocytes during development and under pathological conditions.

DOI： 10.1152/ajpregu.00862.2007

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

The kidney glomerulus plays a pivotal role in ultrafiltration of plasma into urine and also is the locus of kidney disease progressing to chronic renal failure. We have focused proteomic analysis on the glomerulus that is most proximal to the disease locus. In the present study, we aimed to provide a confident, in-depth profiling of the glomerulus proteome. The glomeruli were highly purified from the kidney cortex from a male, 68-year-old patient who underwent nephroureterectomy due to ureter carcinoma. The patient was normal in clinical examinations including serum creatinine and urea levels and liver function, and did not receive any chemotherapy and radiotherapy. The cortical tissue was histologically normal, and no significant deposition of immunoglobulins and complement C3 was observed. We employed a novel strategy of protein separation using 1D (SDS-PAGE) and 2D (solution-phase IEF in combination with SDS-PAGE) prefractionation prior to the shotgun analysis with LC-MS/MS. The protein prefractionation produced 90 fractions, and eventually provided a confident set of identified proteins consisting of 6686 unique proteins (3679 proteins with two or more peptide matches and 3007 proteins with one peptide match), representing 2966 distinct genes. All the identified proteins were annotated and classified in terms of molecular function and biological process, compiled into 1D and 2D protein arrays, consisting of 15 and 75 sections, corresponding to the protein fractions which were defined by MW and pI range, and deposited on a Web-based database (http://www.hkupp.org). The most remarkable feature of the glomerulus proteome was a high incidence of identification of cytoskeleton-related proteins, presumably reflecting the well-developed, cytoskeletal organization of glomerular cells related to their physiological functions.

PubMed

researchmap

Language：English   Publishing type：Doctoral thesis  

researchmap

researchmap

researchmap

researchmap

Language：Japanese   Presentation type：Poster presentation  

researchmap

researchmap

researchmap

researchmap