PubMed

Related Articles Comparative metabolomic analysis reveals a reactive oxygen species-dominated dynamic model underlying chilling environment adaptation and tolerance in rice. New Phytol. 2016 Sep;211(4):1295-310 Authors: Zhang J, Luo W, Zhao Y, Xu Y, Song S, Chong K Abstract Cold, a major environmental stress for plants, has been studied intensively for decades. Its response system has been revealed, especially at the transcriptional level. The mechanisms underlying recovery growth and environmental adaptation, however, remain unknown. Taking advantage of a naturally existing system, two subspecies of Asian cultivated rice (Oryza sativa) with significant divergence in chilling tolerance, we analyzed representative japonica and indica varieties, Nipponbare and 93-11, using comparative metabolomic analysis at six time points covering chilling treatment and recovery. In total, 223 known metabolites were detected. During chilling treatment, significant biochemical changes were centered on antioxidation. During recovery, a wide-ranging chilling response was observed. Large-scale amino acid accumulation occurred, consistent with the appearance of chilling injury. At the mid-treatment stage, the accumulation of antioxidation-related compounds appeared earlier in Nipponbare than in 93-11, consistent with the higher reactive oxygen species (ROS) levels in japonica vs indica varieties. A significant contribution of ROS-mediated gene regulation, rather than the C-repeat binding factor/dehydration-responsive-element binding factor (CBF/DREB) regulon, to the more vigorous transcriptional stress response in Nipponbare was revealed by RNA-seq. Accordingly, during recovery, the induction of stress-tolerant-related metabolites was more active in the chilling-tolerant variety Nipponbare. Senescence-related compounds accumulated only in the chilling-sensitive variety 93-11. Our study uncovers the dynamic metabolic models underlying chilling response and recovery, and reveals a ROS-dominated rice adaptation mechanism to low-temperature environments. PMID: 27198693 [PubMed - indexed for MEDLINE]

Related Articles Brain and blood metabolite signatures of pathology and progression in Alzheimer disease: A targeted metabolomics study. PLoS Med. 2018 Jan;15(1):e1002482 Authors: Varma VR, Oommen AM, Varma S, Casanova R, An Y, Andrews RM, O'Brien R, Pletnikova O, Troncoso JC, Toledo J, Baillie R, Arnold M, Kastenmueller G, Nho K, Doraiswamy PM, Saykin AJ, Kaddurah-Daouk R, Legido-Quigley C, Thambisetty M Abstract BACKGROUND: The metabolic basis of Alzheimer disease (AD) is poorly understood, and the relationships between systemic abnormalities in metabolism and AD pathogenesis are unclear. Understanding how global perturbations in metabolism are related to severity of AD neuropathology and the eventual expression of AD symptoms in at-risk individuals is critical to developing effective disease-modifying treatments. In this study, we undertook parallel metabolomics analyses in both the brain and blood to identify systemic correlates of neuropathology and their associations with prodromal and preclinical measures of AD progression. METHODS AND FINDINGS: Quantitative and targeted metabolomics (Biocrates AbsoluteIDQ [identification and quantification] p180) assays were performed on brain tissue samples from the autopsy cohort of the Baltimore Longitudinal Study of Aging (BLSA) (N = 44, mean age = 81.33, % female = 36.36) from AD (N = 15), control (CN; N = 14), and "asymptomatic Alzheimer's disease" (ASYMAD, i.e., individuals with significant AD pathology but no cognitive impairment during life; N = 15) participants. Using machine-learning methods, we identified a panel of 26 metabolites from two main classes-sphingolipids and glycerophospholipids-that discriminated AD and CN samples with accuracy, sensitivity, and specificity of 83.33%, 86.67%, and 80%, respectively. We then assayed these 26 metabolites in serum samples from two well-characterized longitudinal cohorts representing prodromal (Alzheimer's Disease Neuroimaging Initiative [ADNI], N = 767, mean age = 75.19, % female = 42.63) and preclinical (BLSA) (N = 207, mean age = 78.68, % female = 42.63) AD, in which we tested their associations with magnetic resonance imaging (MRI) measures of AD-related brain atrophy, cerebrospinal fluid (CSF) biomarkers of AD pathology, risk of conversion to incident AD, and trajectories of cognitive performance. We developed an integrated blood and brain endophenotype score that summarized the relative importance of each metabolite to severity of AD pathology and disease progression (Endophenotype Association Score in Early Alzheimer's Disease [EASE-AD]). Finally, we mapped the main metabolite classes emerging from our analyses to key biological pathways implicated in AD pathogenesis. We found that distinct sphingolipid species including sphingomyelin (SM) with acyl residue sums C16:0, C18:1, and C16:1 (SM C16:0, SM C18:1, SM C16:1) and hydroxysphingomyelin with acyl residue sum C14:1 (SM (OH) C14:1) were consistently associated with severity of AD pathology at autopsy and AD progression across prodromal and preclinical stages. Higher log-transformed blood concentrations of all four sphingolipids in cognitively normal individuals were significantly associated with increased risk of future conversion to incident AD: SM C16:0 (hazard ratio [HR] = 4.430, 95% confidence interval [CI] = 1.703-11.520, p = 0.002), SM C16:1 (HR = 3.455, 95% CI = 1.516-7.873, p = 0.003), SM (OH) C14:1 (HR = 3.539, 95% CI = 1.373-9.122, p = 0.009), and SM C18:1 (HR = 2.255, 95% CI = 1.047-4.855, p = 0.038). The sphingolipid species identified map to several biologically relevant pathways implicated in AD, including tau phosphorylation, amyloid-β (Aβ) metabolism, calcium homeostasis, acetylcholine biosynthesis, and apoptosis. Our study has limitations: the relatively small number of brain tissue samples may have limited our power to detect significant associations, control for heterogeneity between groups, and replicate our findings in independent, autopsy-derived brain samples. CONCLUSIONS: We present a novel framework to identify biologically relevant brain and blood metabolites associated with disease pathology and progression during the prodromal and preclinical stages of AD. Our results show that perturbations in sphingolipid metabolism are consistently associated with endophenotypes across preclinical and prodromal AD, as well as with AD pathology at autopsy. Sphingolipids may be biologically relevant biomarkers for the early detection of AD, and correcting perturbations in sphingolipid metabolism may be a plausible and novel therapeutic strategy in AD. PMID: 29370177 [PubMed - in process]

Related Articles Targeted metabolomic analysis of 33 amino acids and biogenic amines in human urine by ion-pairing HPLC-MS/MS: biomarkers for tacrolimus nephrotoxicity after renal transplantation. Biomed Chromatogr. 2018 Jan 25;: Authors: Xia T, Fu S, Wang Q, Wen Y, Chan SA, Zhu S, Gao S, Tao X, Zhang F, Chen W Abstract BACKGROUND: Calcineurin inhibitors (CNIs) nephrotoxicity especially for the widely applicable tacrolimus has become a major concern in post-transplant immunosuppression. Multi-parametric amino acid metabolomics is instrumental for biomarker identification of tacrolimus (Tac) nephrotoxicity, for which specific quantitative methods is highlighted as a premise. METHODS: This article presented a targeted metabolomic assay to quantify 33 amino acids and biogenic amines in human urine by high performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS). Chromatographic separation was carried out on an Agilent Zorbax SB-C18 column (3.0 mm×150 mm, 5 μm) with addition of an ion-pairing agent in the mobile phase, and MS/MS detection was achieved in both the positive and negative multiple reaction monitoring (MRM) mode. RESULTS: Good correlation coefficients (r2 >0.98) were obtained for most analytes. Intra- and inter- day precision, stability, carryover and incurred sample reanalysis met with the acceptance criteria of the FDA Guidance (2001). Analysis on urine from healthy volunteers and renal transplantation patients with Tac nephrotoxicity confirmed symmetric dimethylarginine (SDMA) and serine (Ser) as biomarker at kidney injury, with AUC values of 0.95 and 0.81 in ROC analysis, respectively. Additionally, SDMA exhibited a tight correlation with serum creatinine, and was therefore indicative of renal function. CONCLUSIONS: The targeted metabolomic assay was time and cost prohibitive for amino acid analysis in human urine, facilitating the biomarker identification of Tac nephrotoxicity. PMID: 29369388 [PubMed - as supplied by publisher]

Related Articles The Role of Mitochondrial DNA (mtDNA) in the Development of Diabetic Retinopathy (DR): A Systematic Review. Med Hypothesis Discov Innov Ophthalmol. 2017;6(2):30-38 Authors: Sarhangi N, Khatami F, Keshtkar A, Heshmat R, Atlasi R, Mohammadamoli M Abstract Diabetic Retinopathy (DR) is the most prevalent health problem, which is influenced by environmental and genetic factors with an increasing prevalence. The current systematic review is focused on mtDNA modification, including polymorphism and mutation/deletion, with a direct effect on DR.This systematic search was initially done through PubMed, Cochrane, EMBASE, SCOPUS, and Web of Science without a restriction on the years of publication. The terms searched included ''mtDNA'', ''mitochondrial DNA'', ''diabetes'', ''diabetic'', ''retina'', and ''diabetic retinopathy''. Animal, cohort, cross-sectional, and in vitro studies, as well as case series, case reports, review articles, and Letters to Editor were excluded from this research.From 1528 resulting searched articles, only 12papers were finally chosen as the case-control studies considering mtDNA gene and DR. Actually, of these 12 articles, 8 studies were concerned with mtDNA polymorphisms (UCP1, UCP2, ROMO-1, and Mn-SOD) and 4 articles were related to mtDNA mutation (A3243G mutation in tRNALeu(UUR) gene and mtDNA deletion (ΔmtDNA 4977)).Some conflicting results were found between the selected genetic modifications of mtDNA, such as Mn-SOD, UCP1, ΔmtDNA 4977, tRNALeu (UUR), and ROMO-1.Finally, A3243G mutation in the tRNALeu (UUR) gene and rs660339 and V16A polymorphisms of UCP2 and Mn-SOD genes were respectively considered as the most important factors in the pathogenesis of DR. PMID: 29367932 [PubMed]

Related Articles A comparison of sample preparation methods for extracting volatile organic compounds (VOCs) from equine faeces using HS-SPME. Metabolomics. 2018;14(2):19 Authors: Hough R, Archer D, Probert C Abstract Introduction: Disturbance to the hindgut microbiota can be detrimental to equine health. Metabolomics provides a robust approach to studying the functional aspect of hindgut microorganisms. Sample preparation is an important step towards achieving optimal results in the later stages of analysis. The preparation of samples is unique depending on the technique employed and the sample matrix to be analysed. Gas chromatography mass spectrometry (GCMS) is one of the most widely used platforms for the study of metabolomics and until now an optimised method has not been developed for equine faeces. Objectives: To compare a sample preparation method for extracting volatile organic compounds (VOCs) from equine faeces. Methods: Volatile organic compounds were determined by headspace solid phase microextraction gas chromatography mass spectrometry (HS-SPME-GCMS). Factors investigated were the mass of equine faeces, type of SPME fibre coating, vial volume and storage conditions. Results: The resultant method was unique to those developed for other species. Aliquots of 1000 or 2000 mg in 10 ml or 20 ml SPME headspace were optimal. From those tested, the extraction of VOCs should ideally be performed using a divinylbenzene-carboxen-polydimethysiloxane (DVB-CAR-PDMS) SPME fibre. Storage of faeces for up to 12 months at - 80 °C shared a greater percentage of VOCs with a fresh sample than the equivalent stored at - 20 °C. Conclusions: An optimised method for extracting VOCs from equine faeces using HS-SPME-GCMS has been developed and will act as a standard to enable comparisons between studies. This work has also highlighted storage conditions as an important factor to consider in experimental design for faecal metabolomics studies. PMID: 29367839 [PubMed]

Related Articles Ginseng polysaccharides enhanced ginsenoside Rb1 and microbial metabolites exposure through enhancing intestinal absorption and affecting gut microbial metabolism. J Ethnopharmacol. 2018 Jan 20;: Authors: Shen H, Gao X, Li T, Jing W, Han B, Jia Y, Hu N, Yan Z, Li S, Yan R Abstract ETHNOPHARMACOLOGICAL RELEVANCE: Polysaccharides and small molecules commonly co-exist in decoction of traditional Chinese medicines (TCMs). Our previous study outlined that ginseng polysaccharides (GP) could interact with co-existing ginsenosides to produce synergistic effect in an over-fatigue and acute cold stress model via gut microbiota involved mechanisms. AIM OF THE STUDY: This study aimed to verify the interactions by examining the impact of GP on oral pharmacokinetics of ginsenoside Rb1 (Rb1), the dominant protopanoxadiol (PPD)-type ginsenoside in Ginseng, on a dextran sulphate sodium (DSS) induced experimental colitis model which was characterized by gut dysbiosis, and to delineate the underlying mechanisms in vitro. MATERIALS AND METHODS: Rats received drinking water (normal group), 5% DSS (UC group), or 5% DSS plus daily oral administration of GP (GP group) for 7 days and fecal samples were collected on day -3, 0 and 6. On day 7 all animals received an oral dosage of Rb1 and blood samples were withdrawn for pharmacokinetic study. The in vitro metabolism of Rb1 with gut microbiota from normal and UC rats and the transport of Rb1 across Caco-2 cell monolayer were carried out in presence/absence of GP. Rb1 and its bacterial metabolites ginsenoside Rd (Rd), ginsenoside F2 (F2), Compound K (CK) and PPD were determined using LC-MS/MS. Total and target bacteria in fecal samples were determined by using 16S rRNA-based RT-PCR. β-Glucosidase activity was determined by measuring 4-nitrophenol formed from 4-nitrophenyl-β-D-glucopyranoside hydrolysis. RESULTS: DSS induction did not alter AUC0-t and Cmax of Rb1, which, however, were doubled together with elevated AUC0-t of the metabolites, in particular Rd and CK, in GP group. GP influenced the microbial composition and showed a prebiotic-like effect. Accordingly, GP treatment could partially restore the β-glucosidase activity which was reduced by DSS induction. The presence of GP resulted in quicker microbial metabolism of Rb1 and higher Rd formation in first 8h of incubation, while the impact on F2 and CK formation/conversion became obvious after 8h. More interestingly, GP slightly stimulated Caco-2 cell growth and facilitated Rb1 transport across the Caco-2 monolayer in both directions, increasing the Papp of Rb1 from 10-7cm/s to 10-6cm/s. CONCLUSIONS: GP alleviated DSS-induced colitis-like symptoms and enhanced the systemic exposure of Rb1 through enhancing microbial deglycosylation and intestinal epithelial absorption of Rb1. These findings further demonstrated the important role of gut microbiota in the multifaceted action of polysaccharides in the holistic actions of traditional decoction of TCMs. PMID: 29366768 [PubMed - as supplied by publisher]

Related Articles Microbe participation in aroma production during soy sauce fermentation. J Biosci Bioeng. 2018 Jan 20;: Authors: Harada R, Yuzuki M, Ito K, Shiga K, Bamba T, Fukusaki E Abstract Soy sauce is a traditional Japanese fermented seasoning that contains various constituents such as amino acids, organic acids, and volatiles that are produced during the long fermentation process. Although studies regarding the correlation between microbes and aroma constituents have been performed, there are no reports about the influences of the microbial products, such as lactic acid, acetic acid, and ethanol, during fermentation. Because it is known that these compounds contribute to microbial growth and to changes in the constituent profile by altering the moromi environment, understanding the influence of these compounds is important. Metabolomics, the comprehensive study of low molecular weight metabolites, is a promising strategy for the deep understanding of constituent contributions to food characteristics. Therefore, the influences of microbes and their products such as lactic acid, acetic acid, and ethanol on aroma profiles were investigated using gas chromatography/mass spectrometry (GC/MS)-based metabolic profiling. The presence of aroma constituents influenced by microbes and chemically influenced by lactic acid, acetic acid, and ethanol were proposed. Most of the aroma constituents were not produced by adding ethanol alone, confirming the participation of yeast in aroma production. It was suggested that lactic acid bacterium relates to a key aromatic compound, 2,5-dimethyl-4-hydroxy-3(2H)-furanone. However, most of the measured aroma constituents changed similarly in both samples with lactic acid bacterium and acids. Thus, it was clear that the effect of lactic acid and acetic acid on the aroma profile was significant. PMID: 29366719 [PubMed - as supplied by publisher]

Related Articles Lipoprotein particle number and size distribution in apparently healthy spanish population according to sex and age, assessed by nuclear magnetic resonance. Atherosclerosis. 2017 Aug;263:e86 Authors: Gil Serret M, Ibarretxe D, Plana N, Correig X, Masana L, Amigó N PMID: 29366250 [PubMed - in process]

Related Articles Characterization of glycoprotein and lipoprotein profiles of rheumatoid arthritis (RA) patiens by 1H-nuclear magnetic resonance spectroscopy (1H-NMR). Atherosclerosis. 2017 Aug;263:e121 Authors: Fuertes Martín R, Amigó Grau N, Carles Vallvé J, Paredes S, Taverner D, Masana L, Correig Blanchar X PMID: 29365495 [PubMed - in process]

Related Articles Homeostatic control of metabolic and functional fitness of Treg cells by LKB1 signalling. Nature. 2017 08 31;548(7669):602-606 Authors: Yang K, Blanco DB, Neale G, Vogel P, Avila J, Clish CB, Wu C, Shrestha S, Rankin S, Long L, Kc A, Chi H Abstract Regulatory T cells (Treg cells) have a pivotal role in the establishment and maintenance of immunological self-tolerance and homeostasis. Transcriptional programming of regulatory mechanisms facilitates the functional activation of Treg cells in the prevention of diverse types of inflammatory responses. It remains unclear how Treg cells orchestrate their homeostasis and interplay with environmental signals. Here we show that liver kinase B1 (LKB1) programs the metabolic and functional fitness of Treg cells in the control of immune tolerance and homeostasis. Mice with a Treg-specific deletion of LKB1 developed a fatal inflammatory disease characterized by excessive TH2-type-dominant responses. LKB1 deficiency disrupted Treg cell survival and mitochondrial fitness and metabolism, but also induced aberrant expression of immune regulatory molecules including the negative co-receptor PD-1 and the TNF receptor superfamily proteins GITR and OX40. Unexpectedly, LKB1 function in Treg cells was independent of conventional AMPK signalling or the mTORC1-HIF-1α axis, but contributed to the activation of β-catenin signalling for the control of PD-1 and TNF receptor proteins. Blockade of PD-1 activity reinvigorated the ability of LKB1-deficient Treg cells to suppress TH2 responses and the interplay with dendritic cells primed by thymic stromal lymphopoietin. Thus, Treg cells use LKB1 signalling to coordinate their metabolic and immunological homeostasis and to prevent apoptotic and functional exhaustion, thereby orchestrating the balance between immunity and tolerance. PMID: 28847007 [PubMed - indexed for MEDLINE]

33 new pubmed citations were retrieved for your search. Click on the search hyperlink below to display the complete search results: metabolomics These pubmed results were generated on 2018/01/25PubMed comprises more than millions of citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full-text content from PubMed Central and publisher web sites.

33 new pubmed citations were retrieved for your search. Click on the search hyperlink below to display the complete search results: metabolomics These pubmed results were generated on 2018/01/25PubMed comprises more than millions of citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full-text content from PubMed Central and publisher web sites.

25 new pubmed citations were retrieved for your search. Click on the search hyperlink below to display the complete search results: metabolomics These pubmed results were generated on 2018/01/24PubMed comprises more than millions of citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full-text content from PubMed Central and publisher web sites.

25 new pubmed citations were retrieved for your search. Click on the search hyperlink below to display the complete search results: metabolomics These pubmed results were generated on 2018/01/24PubMed comprises more than millions of citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full-text content from PubMed Central and publisher web sites.

17 new pubmed citations were retrieved for your search. Click on the search hyperlink below to display the complete search results: metabolomics These pubmed results were generated on 2018/01/23PubMed comprises more than millions of citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full-text content from PubMed Central and publisher web sites.

17 new pubmed citations were retrieved for your search. Click on the search hyperlink below to display the complete search results: metabolomics These pubmed results were generated on 2018/01/23PubMed comprises more than millions of citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full-text content from PubMed Central and publisher web sites.

Metabolomics in Sepsis and Its Impact on Public Health. Public Health Genomics. 2018 Jan 19;: Authors: Evangelatos N, Bauer P, Reumann M, Satyamoorthy K, Lehrach H, Brand A Abstract Sepsis, with its often devastating consequences for patients and their families, remains a major public health concern that poses an increasing financial burden. Early resuscitation together with the elucidation of the biological pathways and pathophysiological mechanisms with the use of "-omics" technologies have started changing the clinical and research landscape in sepsis. Metabolomics (i.e., the study of the metabolome), an "-omics" technology further down in the "-omics" cascade between the genome and the phenome, could be particularly fruitful in sepsis research with the potential to alter the clinical practice. Apart from its benefit for the individual patient, metabolomics has an impact on public health that extends beyond its applications in medicine. In this review, we present recent developments in metabolomics research in sepsis, with a focus on pneumonia, and we discuss the impact of metabolomics on public health, with a focus on free/libre open source software. PMID: 29353273 [PubMed - as supplied by publisher]

NMR-based serum metabolomics study reveals a innovative diagnostic model for missed abortion. Biochem Biophys Res Commun. 2018 Jan 15;: Authors: Wu Z, Jin L, Zheng W, Zhang C, Zhang L, Chen Y, Guan J, Fei H Abstract A missed abortion (MA) is an in-utero death of the embryo or fetus before the 20th week of gestation with retained products of conception. In order to discover novel biomarkers for MA, a 1H NMR spectroscopy-based metabolomics approach was applied to detect human MA serum metabolic profiles. Serum samples were obtained from patients with MA (n = 15) and healthy controls (n = 9) for study. The NOESYPR1D spectrum combined with multi-variate pattern recognition analysis was used to cluster the groups and establish a disease-specific metabolites phenotype. Principal component analysis (PCA) and orthogonal partial least-squares discriminant analysis (OPLS-DA) models were capable of distinguishing MA patients from healthy subjects. The results revealed that 24 metabolites altered in MA patients compared with the control population. Metabolomic pathway analysis demonstrated that alanine, aspartate and glutamate metabolism, citrate cycle (TCA cycle), taurine and hypotaurine metabolism were significantly altered in MA. The results indicated that serum NMR-based metabolomic profiling method is sensitive and specific enough to distinguish MA and from healthy controls, this method could be developed as a clinically useful diagnostic tool for MA. The finding from the MA serum metabolic profiling shed a new light on further understanding of MA disease mechanisms. PMID: 29353036 [PubMed - as supplied by publisher]

Urine and plasma metabolomics study on potential hepatoxic biomarkers identification in rats induced by Gynura segetum. J Ethnopharmacol. 2018 Jan 15;: Authors: Shoubei Q, Haixia Z, Qianqian F, Fenxia Z, Jing W, Xiaobin J, Bin C Abstract ETHNOPHARMACOLOGICAL RELEVANCE: Gynura segetum (GS) is an herbal medicine containing Pyrrolizidine Alkaloids (PAs) that causes hepatic sinusoidal obstruction syndrome (HSOS). AIM OF THE STUDY: To discover potential biomarkers and metabolic mechanisms involved in the hepatotoxicity induced by GS. METHODS: SD rats were randomly divided into 4 groups including Saline, the decoction of GS high, medium and low dosage at dosages of 3.75g • kg-1, 7.5g • kg-1 and 15g • kg-1. A metabolomics approach using Ultraperformance Liquid Chromatography -Quadrupole-Time-of-Flight / Mass Spectrometry (UPLC-Q-TOF/MS) was developed to perform the plasma and urinary metabolic profiling analysis, and identified differential metabolites by comparing the saline control group and decoction of GS groups. RESULTS: The herbal was presented dosage-dependent led to ingravescence of hepatotoxicity after the rats were consecutively given with the decoction of GS at varied dosages. A total of 18 differential metabolites of decoction of GS-induced hepatotoxicity were identified, while 10 of them including arginine, proline, glutamate, creatine, valine, linoleic acid, arachidonic acid, sphinganine, phytosphingosine, and citric acid could be discovered in urine and plasma, and primarily involved in Amino acid metabolism, Lipids metabolism and Energy metabolism. CONCLUSIONS: The results suggested that the differential metabolites of arginine, creatine, valine, glutamine and citric acid were verified as potential markers of GS-induced hepatotoxicity via the regulation of multiple metabolic pathways primarily involving in Amino acids metabolism and Energy metabolism. PMID: 29353003 [PubMed - as supplied by publisher]

Fc gamma receptor binding profile of anti-citrullinated protein antibodies in immune complexes suggests a role for FcγRI in the pathogenesis of synovial inflammation. Clin Exp Rheumatol. 2018 Jan 15; Authors: Kempers AC, Nejadnik MR, Rombouts Y, Ioan-Facsinay A, van Oosterhout M, Jiskoot W, Huizinga TWJ, Toes REM, Scherer HU Abstract OBJECTIVES: Anti-citrullinated protein antibodies (ACPA) are highly specific for rheumatoid arthritis (RA). Here, we studied binding of ACPA-IgG immune complexes (IC) to individual Fc gamma receptors (FcγR) to identify potential effector mechanisms by which ACPA could contribute to RA pathogenesis. METHODS: ACPA-IgG1 and control IgG1(IgG1 depleted of ACPA-IgG1) were isolated from plasma and synovial fluid (SF) of RA patients by affinity chromatography using CCP2 peptides. Subsequently, IC were generated using fluorescently labelled F(ab')2 fragments against the F(ab')2 region of IgG, or by using citrullinated fibrinogen. IC were incubated with FcγR-transfected CHO cell lines or neutrophils from healthy donors. FcγR binding of IC was analysed by flow cytometry in the presence or absence of specific blocking antibodies. RESULTS: ACPA-IgG1 IC predominantly bound to FcγRI and FcγRIIIA on FcγR-transfected CHO cell lines, while much lower binding was observed to FcγRIIA and FcγRIIB. ACPA-IgG1 IC showed reduced binding to FcγRIIIA compared to control IgG1 IC, in line with enhanced ACPA-IgG1 Fc core-fucosylation. Neutrophils activated in vitro to induce de novo expression of FcγRI showed binding of ACPA-IgG IC, and blocking studies revealed that almost 30% of ACPA-IgG IC binding to activated neutrophils was mediated by FcγRI. CONCLUSIONS: Our studies show that ACPA-IgG1 IC bind predominately to activating FcγRI and FcγRIIIA, and highlight FcγRI expressed by activated neutrophils as relevant receptor for these IC. As neutrophils isolated from SF exhibit an activated state and express FcγRI in the synovial compartment, this IC-binding could contribute to driving disease pathogenesis in RA. PMID: 29352854 [PubMed - as supplied by publisher]