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Background: For relapsing polychondritis (RP), no useful biomarkers have yet been identified. We analyzed serum peptide profiles to identify candidate biomarkers. Methods: Patients with RP or rheumatoid arthritis (RA) and healthy control (HC) subjects were divided into training set (RP, n=19; RA, n=21; HC, n=17) and testing set (RP, n=18; RA, n=21; HC, n=18). Seven patients demonstrating granulomatosis with polyangiitis (GPA) were used for validation. The ion intensity of serum peptides was comprehensively measured by matrix-assisted laser desorption/ionization time-of-flight/time-of-flight mass spectrometry. Results: One hundred sixty serum peptides were detected. In the RP group of the training set, 24, 8, and 7 peptides showed a ³1.2-fold difference in ion intensity in comparison to the HC, RA, and HC+RA (non-RP) groups, respectively (p the RP/nonRP-4P-2 model provided 83.3% sensitivity and 71.7% specificity in the testing set with GPA group (AUROC, 0.802). Conclusion: Serum peptide profiles provided useful candidate biomarkers for RP and may be implicated in the pathophysiology of RP. Trial registration: University Hospital Medical Information Network Clinical Trials Registry (UMIN-CTR), UMIN 000037212. Registered on 30 June 2019.

Background Malignant gliomas are characterized by high invasive ability. In this study, we investigated roles of layilin, a C-type lectin-homologous protein, in the invasive ability of malignant glioma cells. Methods Expression of layilin was investigated by western blotting in the malignant glioma cell lines of U251-MG, A172, and T98G and in astrocytes. The effects of layilin-knockdown on the expression and protein levels of snail family transcriptional repressor 1 (SNAI1), a transcriptional factor involved in the acquisition and enhancement of invasive ability in malignant gliomas, and on the expression of its target genes, matrix metalloproteinase 2 (MMP2), MMP9, and collagen type I alpha 1 chain (COL1A1), were investigated by qPCR and/or western blotting. Furthermore, the effects of layilin-knockdown on the expression and protein levels of metastasis associated 1 family member 3 (MTA3), a transcriptional repressor of SNAI1, were also investigated by qPCR and western blotting. Finally, the effects of layilin-knockdown on the invasive ability of the cells were investigated by a wound healing assay. Results All the tested malignant glioma cells highly expressed layilin, compared to astrocytes, one of representative glial cell types. Layilin-knockdown reduced SNAI1 both at the mRNA and protein levels in A172 cells, and consequently mRNA levels of MMP2, MMP9, and COL1A1 were also reduced. Furthermore, layilin-knockdown increased nuclear protein levels of MTA3 in A172 cells. Notably, layilin-knockdown suppressed the invasive ability of the cells. Conclusion Layilin up-regulates the expression of SNAI1 via down-regulation of MTA3. This process enhances the invasive ability of malignant glioma cells.

Object Functions of layilin, a type 1 transmembrane protein with a C-type lectin motif, remain to be clarified. We here investigated precise intracellular localization of layilin and the location-related functions. Methods We used HEK293T cells to assess the co-localization of layilin with different individual organelle markers by double immunostaining. We then investigated mitochondrial morphology in layilin-knockdown (KD) conditions, also with immunostaining. Next, we measured amounts of proteins involved in regulation of mitochondrial dynamics, DRP1, pS616-DRP1, mitofusin1, mitofusin2, CDK1, pY15-CDK1, and cyclin B1, in layilin-KD cells versus control cells by Western blot. Furthermore, by using layilin-knockout (KO) cells, amounts of CDK1 and pY15-CDK1 as well as mitochondrial morphology were investigated. Result We found that layilin localized to mitochondria rather than the other organelles. Small round-shape mitochondria were observed in control cells, whereas elongated and highly connected mitochondria were observed in layilin-KD cells. Amounts of active DRP1 (pS616-DRP1) and total DRP1 were significantly smaller in layilin-KD cells than in controls. Amounts of inactive CDK1 (pY15-CDK1) were significantly larger in layilin-KD cells than in controls. No other tested molecules were significantly altered in layilin-KD cells. Amounts of inactive CDK1 were significantly larger in layilin-KO cells than in wild type (WT) cells. Small round-shape mitochondria were observed in WT cells, whereas elongated and highly connected mitochondria were observed in layilin-KO cells. Conclusion We here demonstrated that layilin played a role in the maintenance of fragmented mitochondria in mitochondrial dynamics and that this function needed CDK1 and DRP1 activation. Our data unveiled a novel function for layilin, regulation of mitochondrial dynamics.

Psoriasis is a refractory inflammatory disease, however, its pathophysiology is still not fully understood.We tried to identify novel serum peptides associated with the pathophysiology of psoriasis.Serum peptides from 24 patients with psoriasis vulgaris (PV), 10 patients with psoriatic arthritis (PsA), 14 patients with atopic dermatitis (AD), and 23 healthy control (HC) subjects were analyzed by mass spectrometry. The effects of some peptides on the secretion of humoral factors from dermal cells were investigated by cytokine arrays and ELISAs.A total of 93 peptides were detected. 24, 20, 23, and 2 peptides showed at least 1.2-fold difference in ion intensity between the psoriasis (PV+PsA) and HC groups, between the PV+PsA and AD groups, between the PV and PsA groups, and between patients with severe-to-moderate PV (n=6) and those with mild PV (n=18), respectively (p0.05). 13 out of 27 peptides that showed at least 1.5-fold ion intensity difference in the abovementioned 4 comparisons were identified. The parent proteins of the identified peptides included a coagulation factor, proteins involved in the maintenance of skin, and a protein relating to cytoskeleton. We focused on 2 peptides that were increased in the PV+PsA group: a fibrinogen α chain-derived peptide (1462m/z), the unmodified form of which was fibrinopeptide A-des-alanine (FPAdA), and a filaggrin (FLG)-derived peptide (1977m/z), a modified form of FLGThe results suggested that some serum peptides are involved in the pathophysiology of psoriasis, regulating the secretion of inflammatory chemokines and an antimicrobial protein. The modulation of serum peptides may be a potential therapeutic strategy for psoriasis.

Nuclear factor-κB (NF-κB) is the most potent proinflammatory transactivator, and an inhibitor of NF-κB is a good antiinflammatory drug. Glucocorticoids (GCs) are the strongest and the most frequently used antiinflammatory drugs. GC-bound glucocorticoid receptor (GR) inhibits the transcriptional activity of NF-κB and thereby suppresses a broad range of inflammatory processes. Concurrently, in whole body outside the inflammation area, the GR exerts a lot of hormone action, which results in severe side effects. There is a long-awaited need for a new NF-κB inhibitor. Previously we found a small nuclear acidic protein (named MTI-II, also known as Zn2+-binding protein or parathymosin), which worked as a coactivator of GR. Here we showed that overexpression of MTI-II inhibited a transcriptional activity of NF-κB independently of GCs and the GR. Vise versa, RNA interference suppression of inherent MTI-II enhanced the transcriptional activity of NF-κB. An immunoprecipitation analysis showed that MTI-II precipitated NF-κB after the stimulation of TNFα. Deletion mutants of MTI-II showed that central acidic region is essential for the inhibition of the transcriptional activity of NF-κB. These results suggest that MTI-II would be an inherent inhibitor that interacts with NF-κB. Next, we constructed MTI-II-based antiinflammatory drugs (three fusion proteins of MTI-II with a protein transduction domain and a fusion peptide of the central acidic region with protein transduction domain). These drugs had significant antiinflammatory effects on acute inflammation models and on animal models of human chronic inflammation diseases without an increase of the blood glucose level and repeated-dose toxicity. The MTI-II-based antiinflammatory drug will be a good alternative of GCs.

Background To understand the roles of serum exosomes in rheumatoid arthritis (RA), we comprehensively investigated the protein profiles of serum exosomes in patients with RA. Methods Exosomes were isolated from serum samples obtained from 33 patients (12 with active RA [aRA], 11 with inactive RA [iRA], 10 with osteoarthritis [OA]) and 10 healthy donors (HLs). Proteins extracted from the exosomes were separated by two-dimensional differential gel electrophoresis (2D-DIGE) and identified by mass spectrometry. Results In total, 204 protein spots were detected by 2D-DIGE. In the aRA, iRA, and OA groups, 24, 5, and 7 spots showed approximately ≥ ±1.3-fold intensity differences compared with the HL group, respectively. We were able to identify proteins in six protein spots. Among them, the protein spot identified as Toll-like receptor 3 (TLR3) showed approximately 6-fold higher intensity in the aRA group than in the other groups. Conclusions Patients with active RA possessed considerably different protein profiles of serum exosomes from patients with iRA, patients with OA, and healthy donors. The unique protein profile of serum exosomes, such as the possession of abundant TLR3 fragments, may reflect the pathophysiology of active RA. Electronic supplementary material The online version of this article (10.1186/s41927-018-0041-8) contains supplementary material, which is available to authorized users.

We investigated effects of salazosulfapyridine (SASP) on the protein profile of cell surface (CS)-proteins of SW982, a human synovial sarcoma cell line, using biotinylation of CS-proteins and 2-dimensional fluorescence difference gel electrophoresis (2D-DIGE).SW982 cells were treated with SASP and its metabolites, sulfapyridine (SP) and 5-aminosalicylic acid (5ASA). Then the cells were treated with a membrane-impermeable biotinylating reagent. Biotinylated CS-proteins were isolated using NeutrAvidin-bound beads. CS-proteins affected by the drugs were detected by 2D-DIGE and subjected to mass spectrometry.By the 2D-DIGE analysis, in total 576 spots were detected, 29 out of which showed more than ±1.5-fold different intensity in the SASP-, SP-, and 5ASA-treated cells, compared to non-treated cells (p 0.05). Interestingly, 7 out of the 29 spots changed their intensity only by SASP and 17 spots changed their intensity only by SP. We identified 9 protein from 15 out of the 29 spots, most of which were evidenced to exist on the cell surface by flow cytometry.We found novel effects of SASP and its metabolites on SW982 cells by the combination of biotinylation of cell surface proteins and 2D-DIGE analysis. These data would help understanding of anti-rheumatic actions of SASP. Furthermore, the combination would be a useful method for the analysis of CS-proteins in various conditions.

Objective For diagnosis of dementia with Lewy bodies (DLB), we tried to find blood biomarkers for the disease. Methods Serum peptides were comprehensively detected by mass spectrometry. Peptides of interest were identified by tandem mass spectrometry. Results One hundred forty-six peptides were detected in a training set consisting of 30 DLB patients, 30 patients with Alzheimer's disease (AD), and 28 healthy control (HC) subjects. Multivariate analysis for discriminating the DLB group from the non-DLB (AD and HC) group using ion intensity of four peptides (2898, 4052, 4090, and 5002 m/z) showed sensitivity of 93.3% and specificity of 87.9% (DLB/nonDLB-4P model). In a testing set consisting of 20 DLB patients, 30 AD patients, and 14 HC subjects, this model showed sensitivity of 90.0% and specificity of 88.6%. DLB/nonDLB-4P model detected 86.7% and 90.0% of the AD patients as non-DLB in the training and testing sets, respectively, and discriminated all the 15 patients with amnestic mild cognitive impairment as non-DLB. Notably, a combination of two peptides (1737 and 5002 m/z) showed sensitivity of 95.0% and specificity of 93.3% for discriminating the DLB group from the AD group (DLB/nonDLB-2P model) in the testing set. The peptides used in these models included fragments from complement 4b, Wnt-2b, and lipopolysaccharide-binding protein, which were reported to be involved in the pathology of DLB or Parkinson's disease and hippocampal neurogenesis. Conclusions Serum peptide profiles would provide useful DLB biomarker candidates, which may be implicated in the pathophysiology of the disease. Copyright © 2015 John Wiley & Sons, Ltd.

Aim To explore disease-associated molecules in rheumatoid arthritis (RA), we comprehensively analyzed phosphoproteins purified from RA synoviocytes. Method Synoviocytes were obtained from three patients with RA and three patients with osteoarthritis (OA). Profiles of phosphoproteins purified from the synoviocytes were compared by two-dimensional differential gel electrophoresis (2D-DIGE) between the RA and OA groups. Protein spots with significantly different phosphorylation levels were identified by mass spectrometry. Recombinant protein of annexin A4 (ANXA4), one of the identified phosphoproteins, was transfected into synoviocytes from an OA patient to mimic RA synoviocytes and humoral factor secretion was compared between rANXA4-transfected and non-transfected synoviocytes under a tumor necrosis factor-α (TNFα)-stimulated condition. Results In 2D-DIGE, 318 phosphoprotein spots were detected, of which 94 spots showed significantly different intensities between the two groups (P < 0.05). Among the 94 spots, 22 spots showed two-fold or higher intensity and one spot showed less than 1/2-fold intensity in the RA group compared to the OA group. From the 22 spots, 11 phosphoproteins were identified, which included kinases, carrier and chaperone proteins, cytoskeletal proteins, proteases and calcium-binding proteins. One of the identified calcium-binding proteins was ANXA4, an exocytosis-regulating protein. The transfected rANXA4 was found to be phosphorylated intracellularly, and secretion of chemokine (C-X-C motif) ligand 1 and interleukin-8 induced by TNFα stimulation was significantly suppressed by the transfection (P < 0.01). Conclusion The phosphoprotein profile of RA synoviocytes was different from that of OA synoviocytes. This difference would reflect the different pathophysiologies of the diseases. ANXA4 may be one of therapeutic targets in RA.

Objective To find a blood biomarker and disease-related peptides in Alzheimer's disease (AD), we comprehensively detected serum peptides. Methods Ion intensity of serum peptides from 62 AD patients and 82 control subjects was measured by mass spectrometry. Results A total of 157 peptides were detected from 30 AD patients and 30 healthy control (HC) subjects. Sixty out of the 157 peptide profiles discriminated between the AD and HC groups. Sixteen out of the 60 peptides were identified, 10 out of which were fragments of a fibrinogen α chain (FIBA). Among the 10 peptides, four and six peptides were derived from fibrinopeptide A (FPA, Aα1–16) and the C-terminal region of the αC-domain (αCDC, Aα557–610), respectively. The profile of 10 FIBA-derived peptides combined with age discriminated between the two groups with an area under the receiver operating characteristic curve (AUROC) of 0.940. Validation of this model using a testing set of 32 AD patients and 19 HC subjects showed an AUROC of 0.717, sensitivity of 65.6%, and specificity of 73.7% by a cutoff value of 0.56420. Another value, 0.04029, showed sensitivity of 96.9%, suggesting that subjects with values less than 0.04029 rarely possess AD. FPA and αCDC showed increased ion intensity in the AD group compared with the HC group (p

Edaravone (3-methyl-1-phenyl-2-pyrazolin-5-one) is a free radical scavenger used for acute ischemic stroke. However, it is not known whether edaravone works only as a free radical scavenger or possess other pharmacological actions. Therefore, we elucidated the effects of edaravone on human brain microvascular endothelial cells (HBMECs) by 2 dimensional fluorescence difference gel electrophoresis (2D-DIGE). We found 38 protein spots the intensity of which was significantly altered 1.3 fold on average (p0.05) by the edaravone treatment and successfully identified 17 proteins of those. Four of those 17 proteins were cytoskeleton proteins or cytoskeleton-regulating proteins. Therefore, we subsequently investigated the change of size and shape of the cells, the actin network, and the tight junction of HBMEC by immunocytochemistry. As a result, most edaravone-treated HBMECs became larger and rounder compared with those that were not treated. Furthermore, edaravone-treated HBMECs formed gathering zona occludens (ZO)-1, a tight junction protein, along the junction of the cells. In addition, we found that edaravone suppressed interleukin (IL)-1β-induced secretion of monocyte chemoattractant protein-1 (MCP-1), which was reported to increase cell permeability. We found a novel function of edaravone is the promotion of tight junction formations of vascular endothelial cells partly via the down-regulation of MCP-1 secretion. These data provide fundamental and useful information in the clinical use of edaravone in patients with cerebral vascular diseases.

Both microscopic polyangiitis (MPA) and granulomatosis with polyangiitis (GPA) belong to ANCA-associated vasculitis (AAV), in which neutrophils play a key role in their pathology. In this study, in order to discriminate between MPA and GPA, protein profiles of peripheral blood polymorphonuclear cells (PMNs) of 11 MPA patients and 9 GPA patients and 10 healthy controls (HC) were analyzed by 2D-DIGE. In all the 864 spots detected, intensity of 55 spots was significantly different (p0.05) among the three groups by ANOVA. 31 out of the 55 spots were identified by mass spectrometry. Orthogonal partial-least-squares-discriminate analysis revealed that the abundance profile of the protein spots discriminated the AAV group from the HC group, and the MPA group from the GPA group completely. 13 protein spots were considered as biomarker candidates to distinguish between MPA and GPA. In those, spots whose intensity was higher in MPA than in GPA included actin with various pI values, while a considerable part of spots whose intensity was higher in GPA were proteins related with the activity of neutrophils. Among the candidate proteins, ROC analysis showed that a combination of neutrophil gelatinase-associated lipocalin and a-kinase anchor protein 7 isoforms beta had a high diagnostic potential.In this study, protein profiles of polymorphonuclear cells (PMNs) of microscopic polyangiitis (MPA) and granulomatosis with polyangiitis (GPA) patients and healthy controls (HC) were investigated by 2D-DIGE, and MS analysis. As a result, we found that the protein profiles of PMNs were useful for distinguishing between patients (MPA and GPA) and HC, and between patients with MPA and patients with GPA. Especially, we found that the 13 protein spots that consisted of 10 proteins considerably contributed to the discrimination between MPA and GPA. This is the first to demonstrate that protein profiles of PMNs are different among MPA, GPA and healthy control. The 10 proteins we identified in this study would be new biomarkers for the diagnosis of the diseases, and may be reflect the pathology difference between MPA and GPA.

Hiroyuki Mitsui1, 2), Mitsumi Arito1), Toshiyuki Sato1), Michiyo K. Yokoyama1), Naoya Suematsu1), Kazuki Okamoto1), Manae S. Kurokawa1), Kazuo Yudo3), Hiroshi Nakamura4), Moroe Beppu2) and Tomohiro Kato1,*) 1)Clinical Proteomics and Molecular Medicine, St. Marianna University Graduate School of Medicine, Kawasaki, Japan 2)Department of Orthopedic Surgery and 3)Institute of Medical Science, St. Marianna University School of Medicine, Kawasaki, Japan 4)Department of Rheumatology, Nippon Medical School, Tokyo, Japan

Nuclear factor-κB (NF-κB) is the most potent proinflammatory transactivator, and an inhibitor of NF-κB is a good antiinflammatory drug. Glucocorticoids (GCs) are the strongest and the most frequently used antiinflammatory drugs. GC-bound glucocorticoid receptor (GR) inhibits the transcriptional activity of NF-κB and thereby suppresses a broad range of inflammatory processes. Concurrently, in whole body outside the inflammation area, the GR exerts a lot of hormone action, which results in severe side effects. There is a long-awaited need for a new NF-κB inhibitor. Previously we found a small nuclear acidic protein (named MTI-II, also known as Zn

Aim Biomarkers predicting sustained virological response (SVR) to pegylated interferon-α plus ribavirin (PEG IFN-α/RBV) were investigated. Methods Peptides in pretreatment sera from 107 patients with hepatitis C virus (HCV) genotype 1 were comprehensively analyzed by mass spectrometry. Ion intensity of the peptides was used to generate discriminant models between the responders who achieved SVR (R) and the non-responders (NR) to PEG IFN-α/RBV. Results In total, 107 peptides were detected in a training set (n = 23). A discriminant model using a peptide, complement 3f des-arginine (C3f-dR), showed sensitivity of 35% and specificity of 94% for SVR prediction in a testing set (n = 68). In all the R and NR (n = 96), an area under the receiver–operator curve (AUROC) of 0.64 in the C3f-dR model was increased to 0.78 by addition of platelet (PLT) counts (C3f-dR/PLT model). Another model using the 107 peptides (AUROC, 0.77) also showed higher AUROC (0.79) by addition of hemoglobin (Hb), body mass index (BMI) and age (107P/Hb/BMI/Age model). The sensitivity and specificity of the C3f-dR/PLT model were 59% and 88%, and those of the 107P/Hb/BMI/Age model were 70% and 92%, respectively. The C3f-dR/PLT model showed high AUROC (0.82), similar to that of interleukin-28B rs8099917 genotype analysis (0.86) in the 45 tested patients. Prediction by the combination of the C3f-dR/PLT model, the 107P/Hb/BMI/Age model and the rs8099917 genotype analysis was accurate in 44 out of the 45 patients (AUROC, 0.95). Conclusion Serum peptides, especially C3f-dR, would be useful predictors for SVR to PEG IFN-α/RBV. The complements may be involved in the HCV elimination.

Anti-ribonucleoprotein (anti-RNP) antibodies are one of the representative autoantibodies detectable in patients with systemic lupus erythematosus (SLE) and mixed connective tissue disease (MCTD). Generally, posttranslational modifications (PTMs) on autoantigens are proposed to be involved in the production of autoantibodies. In this study, we tried to detect the alteration in PTMs on a U1 small nuclear RNP 68k subunit (U1-68k), a major antigen of anti-RNP antibodies. Peripheral blood mononuclear cells (PBMCs) were obtained from patients with MCTD, SLE, and rheumatoid arthritis (RA), and from healthy donors. U1-68ks in the PBMCs were detected by 2D Western blot (WB), where extracted nuclear proteins were separated by 2DE, followed by the detection of U1-68k using WB. More than 20 PTM isoforms were detected with different molecular weights of 65.0 , 66.5, and 68.0kDa, and different pIs between 6.0 and 8.5. Importantly, the relative intensity of the spot with 66.5 kDa and pI 7.5 was significantly increased in the MCTD and SLE groups compared to the RA and healthy groups. Further, this U1-68k isoform, in particular, in its RS domain, was found to have significantly decreased phosphorylation compared to the other isoforms. The PTM alternation may be one of the steps to generate the anti-RNP antibodies.

Objective Microscopic polyangiitis (MPA) is necrotizing vasculitis of unknown etiology. We analyzed the serum peptide profile of MPA to find a biomarker for this disease. Methods Serum peptides from 33 patients with MPA, 7 with granulomatosis with polyangiitis (Wegener's), 7 with Churg-Strauss syndrome, 6 with giant cell arteritis, and 25 with systemic lupus erythematosus (SLE) were comprehensively analyzed by mass spectrometry. Peptide function on human microvascular endothelial cells (HMVECs) was examined by enzyme-linked immunosorbent assay and real-time polymerase chain reaction. Results A total of 102 serum peptides were detected from the 78 patients. One of the peptides, peptide 1,523, showed significantly higher ion intensity in MPA (mean ± SD 46.8 ± 39.3 arbitrary units [AU]) than in the other systemic vasculitides (14.1 ± 12.2 AU) (P < 0.05) or in SLE (17.0 ± 12.1 AU) (P < 0.05). In MPA, peptide 1,523 showed significantly higher ion intensity before treatment than 1 week (P < 0.05) and 6 weeks (P < 0.05) after the initiation of treatment. Peptide 1,523 was identified as 13 C-terminal amino acid residues of apolipoprotein A-I (Apo A-I) and was designated “AC13.” Validation of AC13 ion intensity using another MPA cohort (n = 14) similarly showed significantly higher ion intensity (90.1 ± 167.9 AU) compared to 14 patients with rheumatoid arthritis (8.6 ± 5.4 AU) (P < 0.01) and 14 healthy subjects (11.8 ± 6.1 AU) (P < 0.01). Serum concentrations of Apo A-I and high-density lipoprotein cholesterol were down-regulated in MPA before treatment and returned to their normal ranges 6 weeks after the initiation of treatment (both P < 0.01). Stimulation of HMVECs with AC13 significantly up-regulated secretion of interleukin-6 (IL-6) (P < 0.05) and IL-8 (P < 0.01). Conclusion AC13, a candidate biomarker for MPA, may be useful for monitoring disease activity and may exacerbate vascular inflammation through up-regulation of proinflammatory cytokines.

Objective To identify novel proteins involved in the pathogenesis of rheumatoid arthritis (RA) and to characterise the identified proteins based on pathogenic and therapeutic aspects. Methods The authors applied differential phosphoproteomic analysis to articular synoviocytes between RA and osteoarthritis (OA) to identify proteins differently phosphorylated between RA and OA. Focusing on annexin VII (Anx7), one of the highly phosphorylated proteins in RA, the authors prepared Anx7 -transgenic C57BL/6 ( Anx7 -Tg-B6) mice to evaluate their susceptibility to collagen-induced arthritis (CIA). In addition, the authors examined the effect of anti-Anx7 antibodies (Abs) on CIA and serum levels of cytokines in wild-type DBA/1J mice, which are known to be susceptible to CIA, and in Anx7 -Tg-B6 mice. In vitro, the authors examined the effect of the Anx7 knockdown by small interfering RNA on the secretion of cytokines in rheumatoid synoviocytes and the human synovial sarcoma cell line SW982. Results The Anx7 transgene altered the CIA-resistant B6 mice to CIA-susceptible ones. The Abs treatment suppressed CIA even in the wild-type DBA/1J mice. The serum levels of cytokines including interleukin 6 (IL-6) and TNFα were not altered by the Abs treatment in vivo. On the other hand, the knockdown of Anx7 by small interfering RNA caused downregulation of IL-8 secretion in vitro. Conclusions These results indicate that Anx7 participates in the pathogenesis of RA partly through the secretion of IL-8. The study data have demonstrated the pathogenic roles and therapeutic significance of Anx7 in RA for the first time.

Renal biopsy samples are important not only for the diagnosis of glomerulonephritis, but also for the investigation of its pathogenesis. However, it remains difficult to biochemically analyze proteins extracted solely from the glomeruli of needle biopsy samples, since the samples contain various components like renal tubules and connective tissue. Even a recent micro-dissection method, recovering the glomeruli in the sliced sections of the biopsy samples, has not fully solved the difficulty because the amount of obtainable proteins by this method is not usually enough for protein analysis. To overcome this problem, we established a simple but reliable method to isolate whole glomeruli from needle biopsy samples. By this method, termed ‘micro-sieving’, we were able to isolate on average more than 50 glomeruli from a single needle biopsy sample in an hour. The amount of the extracted glomerular proteins was on average 23 µg per biopsy sample. As a representative use of this method, we were able to obtain a glomerular protein profile by fluorescent 2-dimensional electrophoresis for each of the tested patients with glomerulonephritis. ‘Micro-sieving’ can be used widely as a fundamental technique to analyze glomeruli in renal needle biopsy samples.

To promote an understanding of autoimmunity in BD, we surveyed autoAgs in patients with BD and investigated the prevalence and clinical significance of the identified autoAbs. Specifically, proteins, extracted from peripheral blood mononuclear cells and separated by 2DE, were subjected to WB, using five serum samples from patients with BD. The detected candidate autoAgs were identified by mass spectrometry. As a result, 17 autoantigenic spots were detected by the 2DE-WB, out of which eight spots were identified. They are enolase-1, cofilin-1, vimentin, Rho-GDI beta protein, tubulin-like protein, and actin-like proteins. The autoAbs to one of the identified proteins, cofilin-1, were investigated by WB using a recombinant protein in 30 patients with BD, 35 patients with RA, 32 patients with SLE, and 16 patients with PM/DM. The autoAbs to cofilin-1 were detected by WB in four (13.3%) of the 30 patients with BD, five (14.3%) of the 35 patients with RA, two (6.3%) of the 32 patients with SLE, and eight (24.2%) of the 33 patients with PM/DM. Our data indicate that the generation of autoAbs to cofilin-1 may reflect common immunological disorders in BD, RA, and PM/DM. Our data would help understanding of the immunopathology of BD. In addition, the proteomic approach would be a useful way to investigate autoAgs.

We analyzed serum short peptides comprehensively to know whether they were useful to characterize IgA nephropathy (IgAN). Serum samples from 26 patients with untreated IgAN and 25 healthy donors were tested. Short peptides with molecular weights of approximately 7 kDa, purified from the serum samples by magnetic-beads-based weak cation exchange, were detected by mass spectrometry. Then the peptide peaks detected were subjected to the multivariate data analysis by SIMCA-P+ containing principal component analysis (PCA) and orthogonal partial-least-squares-discriminate analysis (OPLS-DA). A total of 92 peptide peaks were detected in the tested serum samples. The OPLS-DA analysis revealed that the profile of all the peptide peak intensities discriminated the IgAN group and the healthy group completely with a high R2 value (0.919) and a high Q2 value (0.861). Further, the profile of only five peptide peaks was found to discriminate the two groups. By tandem mass spectrometry and database searching, three of the five peptides which increased in the IgAN group were identified as fragments of fibrinogen alpha chain, and the two peptides which increased in the healthy group were identified as fragments of complement C3f and kininogen-1 light chain. Taken together, the profile of the serum short peptides would be useful to discriminate IgAN and healthy conditions. Further, the five peptides may be candidate serum markers for IgAN and may be related to pathogenesis of IgA.

To clarify roles of an endogenous pain modulatory system of the central nervous system (CNS) in hyperalgesia, we tried to identify qualitative and quantitative protein changes by a proteomic analysis using an animal model of hyperalgesia. Specifically, we first induced functional hyperalgesia on male Wistar rats by repeated cold stress (specific alternation of rhythm in temperature, SART). We then compared proteomes of multiple regions of CNS and the dorsal root ganglion between the hyperalgetic rats and non-treated ones by 2-D PAGE in the pI range of 4.0-7.0. We found that SART changed the proteomes prominently in the mesencephalon and cerebellum. We thus analyzed the two brain regions in more detail using gels with narrower pI ranges. As a result, 29 and 23 protein spots were significantly changed in the mesencephalon and the cerebellum, respectively. We successfully identified 12 protein spots by a MALDI-TOF/TOF MS and subsequent protein database searching. They included unc-18 protein homolog 67K, collapsin response mediator protein (CRMP)-2 and CRMP-4, which were reported to be involved in neurotransmitter release or axon elongation. Interestingly, mRNA expression levels of these three proteins were not changed significantly by the induction of hyperalgesia. Instead, we found that the detected changes in the protein spots are caused by the post-translational modification (PTM) of proteolysis or phosphorylation. Taken together, development of the hyperalgesia would be linked to PTM of these three CNS proteins. PTM regulation may be one of the useful ways to treat hyperalgesia.

Background Tumor necrosis factor (TNF)-α is suggested to induce epithelial-mesenchymal transformation (EMT) of renal tubular epithelial cells that possibly exacerbates renal interstitial fibrosis in glomerulonephritis (GN). We here investigated whether layilin (LAYN), a c-type lectin-homologous protein, was involved in the EMT process. Methods Expression of LAYN was investigated in kidneys of mice administered with TNF-α and in a clear cell renal carcinoma cell line of KMRC-1 stimulated with TNF-α by quantitative polymerase chain reaction (qPCR) and/or western blotting. Expression of LAYN was assessed immunohistochemically in renal biopsy samples of patients with various types of GN. Changes of EMT markers and cell morphology by TNF-α and transforming growth factor (TGF)-β in LAYN-knocked down KMRC-1 cells were investigated by qPCR and immunocytochemistry. Results Administration of TNF-α increased expression of LAYN in renal tubular epithelia in mice. TNF-α but not TGF-β increased expression of LAYN in KMRC-1 cells. Renal biopsy samples from the patients with GN showed high expression of LAYN in tubular epithelial cells. TNF-α induced up-regulation of vimentin, down-regulation of E-cadherin, and fibroblast-like morphological change in KMRC-1 cells, indicating occurrence of EMT. These changes were not observed in the LAYN-knocked down cells. In contrast, similarly occurred TGF-β-induced EMT was not affected by the LAYN knockdown. Conclusion Our data indicate that LAYN is involved in the TNF-α-induced EMT of renal tubular epithelial cells. LAYN may play roles in the generation of renal interstitial fibrosis in GN via TNF-α-induced EMT.

We evaluated the effectiveness of using Flinders Technology Associates (FTA) filter paper for the polymerase chain reaction (PCR) genotyping of transgenic mice. Tail prick blood sample dried on an FTA filter disc was processed for genomic PCR. It is easy and rapid to prepare DNA templates because the protocol is extraction-free and only requires minimal handling of wash briefly bloodstained FTA filter discs. Progeny of a transgene-positive founder mated with wild-type mice was screened for the presence of the transgene by the filter-based PCR using transgene-specific primers. The resulting amplicons with expected sizes of 3134 bp, 1152 bp, 877 bp and 688 bp were robust and reproducible, allowing a distinction between transgenic (n=44) and wild-type (n=47) mice showing no signal. The filter-based PCR screening took only half a day. The present study confirmed the validity and usefulness of the novel rapid extraction-free genotyping method.

We described a novel purification method for a recombinant glucocorticoid receptor (GR) in detail. The purification procedure consists of sequential chromatographies using common ion-exchange columns (Mono Q and Mono S). This procedure is based upon a new finding that the activated GR binds both to a Mono Q column and to a Mono S column at the same pH. The entire chromatographies took about 3 h and GR represented 97% of the purified protein sample. This purification protocol will be applicable to the purification of native GR, point-mutated recombinant GR and other nuclear receptors.

In our previous screening of chondrocyte protein profiles, the amount of adenosine monophosphate deaminase (AMPD) 2 was found to be decreased by tofacitinib. Extending the study, here we confirmed the decrease of AMPD2 by tofacitinib and further investigated effects of tofacitinib on purine nucleotide metabolism.Human articular chondrocytes and a chondrosarcoma cell line: OUMS-27 were stimulated with tofacitinib. Then the levels of AMPD2 and its related enzymes were investigated by Western blot. The levels of AMP and adenosine were assessed by mass spectrometry.We confirmed the significant decrease of AMPD2 by tofacitinib in chondrocytes (p = 0.025). The levels of adenosine kinase and 5'-nucleotidase were decreased in chondrocytes, although they did not meet statistical significance (p = 0.067 and p = 0.074, respectively). The results from OUMS-27 were similar to those from the chondrocytes. The cellular adenosine levels were significantly decreased by tofacitinib in OUMS-27 (p = 0.014). The cellular AMP levels were increased, although they did not meet statistical significance in OUMS-27 (p = 0.066).Our data indicate that tofacitinib increases the cellular levels of adenosine, which is known to have anti-inflammatory activity, through the downregulation of AMPD2. This would be a novel functional aspect of tofacitinib.

For diagnosis of dementia with Lewy bodies (DLB), we tried to find blood biomarkers for the disease.Serum peptides were comprehensively detected by mass spectrometry. Peptides of interest were identified by tandem mass spectrometry.One hundred forty-six peptides were detected in a training set consisting of 30 DLB patients, 30 patients with Alzheimer's disease (AD), and 28 healthy control (HC) subjects. Multivariate analysis for discriminating the DLB group from the non-DLB (AD and HC) group using ion intensity of four peptides (2898, 4052, 4090, and 5002 m/z) showed sensitivity of 93.3% and specificity of 87.9% (DLB/nonDLB-4P model). In a testing set consisting of 20 DLB patients, 30 AD patients, and 14 HC subjects, this model showed sensitivity of 90.0% and specificity of 88.6%. DLB/nonDLB-4P model detected 86.7% and 90.0% of the AD patients as non-DLB in the training and testing sets, respectively, and discriminated all the 15 patients with amnestic mild cognitive impairment as non-DLB. Notably, a combination of two peptides (1737 and 5002 m/z) showed sensitivity of 95.0% and specificity of 93.3% for discriminating the DLB group from the AD group (DLB/nonDLB-2P model) in the testing set. The peptides used in these models included fragments from complement 4b, Wnt-2b, and lipopolysaccharide-binding protein, which were reported to be involved in the pathology of DLB or Parkinson's disease and hippocampal neurogenesis.Serum peptide profiles would provide useful DLB biomarker candidates, which may be implicated in the pathophysiology of the disease.

Purpose To elucidate effects of salazosulfapyridine (SASP) and methotrexate (MTX), major anti-rheumatic drugs, on exosomes derived from SW982 of a human synovial sarcoma cell line. Experimental design SW982 was treated with SASP and/or MTX under interleukin-1β (IL-1β)-treated or nontreated conditions. Exosomes were isolated from the culture media, and exosomal proteome was analyzed by 2D-DIGE. Protein spots whose intensity was significantly altered by the above treatments were identified by MS. Results Two hundred ninety-four protein spots were detected in the exosome preparations by 2D-DIGE. Compared to the nontreated cells, SASP-, MTX-, and (SASP + MTX)-treated cells displayed 8, 10, and 21 exosomal protein spots with more than ±2.0-fold intensity differences (p < 0.05), respectively. Similarly, the IL-1β-treated cells displayed 58 exosomal protein spots with more than ±1.5-fold intensity differences (p < 0.05). In about half of the 58 spots, the IL-1β-induced intensity changes were suppressed by simultaneous addition of SASP and/or MTX. Most of the identified proteins were immunity- or anti-oxidation-related proteins. Conclusions and clinical relevance The SASP and/or MTX treatments altered the protein profiles of exosomes and suppressed the effects of IL-1β on the exosomal proteome. Exosomes may play roles in the actions of these anti-rheumatic drugs.

Layilin (LAYN) is thought to be involved in reorganization of cytoskeleton structures, interacting with merlin, radixin, and talin. Also, LAYN is known to be one of the receptors for hyaluronic acid (HA). In rheumatoid arthritis (RA), inflammatory cytokines like tumor necrosis factor α (TNF-α) have been known to play pathological roles. HA with low molecular weight is speculated to exacerbate inflammation in RA. In this context, differences of quantity and functions of HA receptors would affect the severity of inflammation in RA. Chondrocytes, which play critical roles in maintaining articular cartilage and are affected in RA, express at least kinds of HA receptors like CD44 and LAYN. However, roles and regulation of LAYN in articular chondrocytes have been poorly understood. To clarify regulation of LAYN in chondrocytes, we here investigated whether TNF-α affected expression levels of LAYN in human articular chondrocytes. Next, to clarify LAYN-specific roles in chondrocytes, we investigated whether binding of antibodies to the extracellular domain of LAYN affected secretion of inflammatory cytokines using a chondrosarcoma cell line. As a result, we found that TNF-α up-regulated expression levels of LAYN in the chondrocytes. Further, the LAYN signaling was found to enhance secretion of inflammatory factors, IL-8 and complement5 (C5)/C5a, from the cells. Our results indicate that LAYN would be involved in the enhancement of inflammation and degradation of cartilage in joint diseases such as RA and OA.

A cytosolic acetyl-CoA hydrolase (CACH) was purified from rat liver to homogeneity by a new method using Triton X-100 as a stabilizer. We digested the purified enzyme with an endopeptidase and determined the N-terminal amino-acid sequences of the two proteolytic fragments. From the sequence data, we designed probes for RT-PCR, and amplified CACH cDNA from rat liver mRNA. The CACH cDNA contains a 1668-bp ORF encoding a protein of 556 amino-acid residues (62 017 Da). Recombinant expression of the cDNA in insect cells resulted in overproduction of functional acetyl-CoA hydrolase with comparable acyl-CoA chain-length specificity and Michaelis constant for acetyl-CoA to those of the native CACH. Database searching shows no homology to other known proteins, but reveals high similarities to two mouse expressed sequence tags (91% and 93% homology) and human mRNA for KIAA0707 hypothetical protein (50% homology) of unknown function.

Sulfasalazine (SSZ) and tofacitinib are effective for treating rheumatoid arthritis, however, their effects on chondrocytes have not been fully understood. We here tried to elucidate their effects on chondrocyte proteins.We treated chondrocytes from five osteoarthritis patients with IL-1β, IL-1β+ SSZ, IL-1β+ tofacitinib, SSZ alone, and tofacitinib alone. Then, we compared protein profiles of the chondrocytes using two-dimensional differential gel electrophoresis. Further, we identified altered proteins by mass spectrometry.Out of 892 detected protein spots, the IL-1β stimulation changed intensity of 43 spots more than 1.3-fold or less than 1/1.3-fold significantly. SSZ suppressed the IL-1β-induced intensity alteration in 16 (37%) out of the 43 protein spots. Tofacitinib suppressed the IL-1β-induced alteration in 4 (9.3%) out of the 43 spots. The production of AMP deaminase 2 and procollagen-lysine, 2-oxoglutarate 5-dioxygenase 2 were increased by IL-1β and the increase was suppressed by SSZ and by tofacitinib. SSZ alone altered intensity of 273 (31%) out of the 852 spots significantly, whereas tofacitinib alone altered intensity of only 24 (2.7%) out of them.SSZ and, to lesser extent, tofacitinib suppress the effects of IL-1β on the protein profiles of chondrocytes. Our data would promote understanding of effects of the drugs on chondrocytes.

Background: To promote understanding of immunoglobulin A nephropathy (IgAN) pathophysiology, we tried to elucidate glomerular protein profiles in IgAN, using microsieving that we established recently to isolate glomeruli from renal biopsy samples and proteomic approaches. Methods: Glomeruli were isolated from renal biopsy samples of patients with IgAN (n = 5) and with minimal change nephrotic syndrome (MCNS; n = 5) using microsieving. Proteins extracted from the isolated glomeruli were separated by 2-dimensional differential gel electrophoresis (2D-DIGE). Proteins with different amounts between the two groups were identified by mass spectrometry. One of the identified proteins, α-actinin-4 (ACTN4), was further analyzed by Western blotting, RT-polymerase chain reaction (PCR), and immunohistochemistry. Results: By 2D-DIGE, 72 out of the detected 1,170 protein spots showed significantly different intensity between the two groups (p < 0.05). Thirty-four out of the 72 protein spots showed more than 1.5-fold or less than 1/1.5-fold intensity, out of which 16 protein spots were successfully identified. No microbial protein was identified. ACTN4 molecules with a low molecular weight of approximately 77 kDa were found to increase in the IgAN group. Lack of an N-terminal part of ACTN4 was demonstrated by Western blotting. No defect of mRNA for ACTN4 was evidenced by RT-PCR. Predominant existence of ACTN4 in capillary walls of glomeruli of IgAN patients was demonstrated by immunohistochemistry in glomerular sections of patients with IgAN. Conclusion: Use of microsieving enabled us to biochemically analyze glomerular proteins in renal biopsy samples from patients with glomerular diseases. With this method, we demonstrated skewed glomerular protein profiles in IgAN.

To find a blood biomarker and disease-related peptides in Alzheimer's disease (AD), we comprehensively detected serum peptides.Ion intensity of serum peptides from 62 AD patients and 82 control subjects was measured by mass spectrometry.A total of 157 peptides were detected from 30 AD patients and 30 healthy control (HC) subjects. Sixty out of the 157 peptide profiles discriminated between the AD and HC groups. Sixteen out of the 60 peptides were identified, 10 out of which were fragments of a fibrinogen α chain (FIBA). Among the 10 peptides, four and six peptides were derived from fibrinopeptide A (FPA, Aα1-16) and the C-terminal region of the αC-domain (αCDC, Aα557-610), respectively. The profile of 10 FIBA-derived peptides combined with age discriminated between the two groups with an area under the receiver operating characteristic curve (AUROC) of 0.940. Validation of this model using a testing set of 32 AD patients and 19 HC subjects showed an AUROC of 0.717, sensitivity of 65.6%, and specificity of 73.7% by a cutoff value of 0.56420. Another value, 0.04029, showed sensitivity of 96.9%, suggesting that subjects with values less than 0.04029 rarely possess AD. FPA and αCDC showed increased ion intensity in the AD group compared with the HC group (p 0.05).The profile of 10 FIBA-derived peptides combined with age would be a candidate biomarker for AD, which facilitates screening of the disease. The significant release of FPA and αCDC may be involved in the aberrant coagulation that leads to vascular damage in AD.

To investigate the pathophysiology of Behçet's disease (BD) and find biomarkers for the disease, we analysed protein profiles of peripheral blood mononuclear cells (PBMCs).Proteins, extracted from PBMCs, were comprehensively analysed in 16 patients with BD, 16 patients with rheumatoid arthritis (RA), 12 patients with Crohn's disease (CD), and 16 healthy control subjects (HC) by 2-dimensional differential gel electrophoResis (2D-DIGE). Differently expressed proteins were identified by mass spectrometry.563 protein spots were detected. We completely discriminated between the BD and HC groups, between the BD and RA groups, and between the BD and CD groups by multivariate analysis of intensity of 23, 35, and 1 spots, respectively. The spots contributing to the differences included proteins related to cytoskeleton, transcription/translation, T cell activation, bone turnover, regulating apoptosis, and microbial infection. Intensity of 3 spots (tyrosine-protein phosphatase non-receptor type 4, threonine synthase-like 2, and β-actin) provided area under the receiver operating characteristic curves (AUROC) of 0.889 for discrimination between the BD group and the non-BD groups. Informatively, intensity of the above 1 spot completely discriminated the CD group from the other groups (AUROC 1.000). This spot, identified as β-actin, had different pI from the above β-actin-spot probably due to different post-translational modification.PBMC protein profiles, especially the profile of the 3 spots, would be candidate biomarkers for BD. The latter β-actin subtype would be useful for discriminating inflammatory bowel diseases from BD and other diseases. The identified proteins may play important roles in the pathophysiology of BD.

Anti-ribonucleoprotein (anti-RNP) antibodies are one of the representative autoantibodies detectable in patients with systemic lupus erythematosus (SLE) and mixed connective tissue disease (MCTD). Generally, posttranslational modifications (PTMs) on autoantigens are proposed to be involved in the production of autoantibodies. In this study, we tried to detect the alteration in PTMs on a U1 small nuclear RNP 68k subunit (U1-68k), a major antigen of anti-RNP antibodies. Peripheral blood mononuclear cells (PBMCs) were obtained from patients with MCTD, SLE, and rheumatoid arthritis (RA), and from healthy donors. U1-68ks in the PBMCs were detected by 2D Western blot (WB), where extracted nuclear proteins were separated by 2DE, followed by the detection of U1-68k using WB. More than 20 PTM isoforms were detected with different molecular weights of 65.0 , 66.5, and 68.0kDa, and different pIs between 6.0 and 8.5. Importantly, the relative intensity of the spot with 66.5 kDa and pI 7.5 was significantly increased in the MCTD and SLE groups compared to the RA and healthy groups. Further, this U1-68k isoform, in particular, in its RS domain, was found to have significantly decreased phosphorylation compared to the other isoforms. The PTM alternation may be one of the steps to generate the anti-RNP antibodies.

Aim To elucidate the pathophysiology of rheumatoid arthritis (RA) as well as osteoarthritis (OA), we analyzed protein profiles of bone marrow-derived adherent cells (BMACs) from patients with these diseases. Methods Proteins, extracted from BMACs from three RA and three OA patients, were comprehensively analyzed by 2-dimensional differential image gel electrophoresis (2D-DIGE). Then a part of the detected proteins, differently expressed between the two diseases, were identified by mass spectrometric analysis. Results 2D-DIGE analysis detected more than 1600 protein spots in both RA and OA BMACs. Out of these, expression of 340 spots was significantly altered between the diseases (more than 1.5-fold: RA > OA, 26 spots; OA > RA, 314 spots; P

In our previous proteomic surveillance, we found that at least 11 proteins in neutrophils were increased more than 2.5-fold by the stimulation of GM-CSF. In this paper, focusing on one of the 11 proteins, S100 calcium binding protein A8 (S100A8), we tried to elucidate the effect of S100A8 and the cooperative effect of S100A8 and GM-CSF on production and secretion of cytokines of neutrophils.S100A8 in neutrophil was detected by western blotting, and concentrations of S100A8 in synovial fluid (SF) from patients with rheumatoid arthritis (RA) and osteoarthritis (OA) were measured by ELISA. Cytokine levels in the culture medium of neutrophils incubated with and without S100A8 were measured by an antibody array. IL-8 and IL-16 levels in the culture medium of neutrophils stimulated with S100A8, GM-CSF, and the combination of S100A8 and GM-CSF were measured by ELISA. The mRNA levels of IL-8 and IL-16 in the stimulated neutrophils were analysed by real-time PCR.The western blotting analysis confirmed that S100A8 is up-regulated in neutrophil by the stimulation of GM-CSF. Furthermore, the ELISA analysis confirmed that S100A8 was significantly elevated in SF of patients with RA compared to SF of patients with OA. S100A8 induced mRNA expression and secretion of IL-8 and IL-16. S100A8 further enhanced production of IL-8 by GM-CSF but not that of IL-16.These data suggest that S100A8 may be involved in the exacerbation of RA, and that S100A8 may be a therapeutic target of RA.

To promote an understanding of autoimmunity in BD, we surveyed autoAgs in patients with BD and investigated the prevalence and clinical significance of the identified autoAbs. Specifically, proteins, extracted from peripheral blood mononuclear cells and separated by 2DE, were subjected to WB, using five serum samples from patients with BD. The detected candidate autoAgs were identified by mass spectrometry. As a result, 17 autoantigenic spots were detected by the 2DE-WB, out of which eight spots were identified. They are enolase-1, cofilin-1, vimentin, Rho-GDI beta protein, tubulin-like protein, and actin-like proteins. The autoAbs to one of the identified proteins, cofilin-1, were investigated by WB using a recombinant protein in 30 patients with BD, 35 patients with RA, 32 patients with SLE, and 16 patients with PM/DM. The autoAbs to cofilin-1 were detected by WB in four (13.3%) of the 30 patients with BD, five (14.3%) of the 35 patients with RA, two (6.3%) of the 32 patients with SLE, and eight (24.2%) of the 33 patients with PM/DM. Our data indicate that the generation of autoAbs to cofilin-1 may reflect common immunological disorders in BD, RA, and PM/DM. Our data would help understanding of the immunopathology of BD. In addition, the proteomic approach would be a useful way to investigate autoAgs.

Unilateral labyrinthectomy (UL) in rats is used as a human vertigo model. In this model, spontaneous nystagmus and dysequilibrium caused by UL are ameliorated within 48–72 hours. The amelioration, termed vestibular compensation (VC), is long lasting. Although cerebellar flocculi have been reported to be involved in VC, the molecular mechanisms behind VC are unknown. In this study, we used 2D-DIGE to detect protein changes in flocculi during acute (48 hours) and chronic (1 week) stages of VC. We found 99 out of 967 protein spots that showed significant changes in their intensities. Of the 99 spots, 45 spots (ipsilateral side, 15; contralateral side, 30) changed unilaterally during the acute stage, whereas 46 spots (ipsilateral side, 21; contralateral side, 25) changed unilaterally during the chronic stage. Thus, the acute compensation mechanism is more complicated in the contralateral flocculus than in the ipsilateral flocculus. Using MALDI-TOF MS, we identified 10 proteins out of the 12 protein spots. Of these, 3 proteins involved in synaptic transmission, neuronal filament formation and vesicular transport, respectively, demonstrated altered expression only in the acute stage. Our results enhance the understanding of the role of the cerebellar flocculi in VC generation.

We analyzed serum short peptides comprehensively to know whether they were useful to characterize IgA nephropathy (IgAN). Serum samples from 26 patients with untreated IgAN and 25 healthy donors were tested. Short peptides with molecular weights of approximately 7 kDa, purified from the serum samples by magnetic-beads-based weak cation exchange, were detected by mass spectrometry. Then the peptide peaks detected were subjected to the multivariate data analysis by SIMCA-P+ containing principal component analysis (PCA) and orthogonal partial-least-squares-discriminate analysis (OPLS-DA). A total of 92 peptide peaks were detected in the tested serum samples. The OPLS-DA analysis revealed that the profile of all the peptide peak intensities discriminated the IgAN group and the healthy group completely with a high R2 value (0.919) and a high Q2 value (0.861). Further, the profile of only five peptide peaks was found to discriminate the two groups. By tandem mass spectrometry and database searching, three of the five peptides which increased in the IgAN group were identified as fragments of fibrinogen alpha chain, and the two peptides which increased in the healthy group were identified as fragments of complement C3f and kininogen-1 light chain. Taken together, the profile of the serum short peptides would be useful to discriminate IgAN and healthy conditions. Further, the five peptides may be candidate serum markers for IgAN and may be related to pathogenesis of IgA.