RESUMO
Inflammatory bowel diseases (IBDs), including Crohn's disease (CD) and ulcerative colitis, are chronic diseases of the gastrointestinal tract, with an unknown etiology, that affect over 6.8 million people worldwide. To characterize disease pathogenesis, proteomic and bioinformatic analyses were performed on colon biopsies collected during diagnostic endoscopy from 119 treatment-naïve pediatric patients, including from 78 IBD patients and 41 non-IBD patients who served as controls. Due to the presence of noninflamed and/or inflamed regions in IBD patients, up to two biopsies were obtained from IBD patients as compared to a single noninflamed biopsy from non-IBD pediatric control patients. Additional biopsies were obtained and analyzed from 33 of the IBD patients after IBD-directed therapeutic intervention for comparison of pre- and post-treatment proteomes. SuperSILAC was utilized to perform quantitative analysis of homogenized tissues, which were processed by filter-aided sample preparation. Hierarchical clustering and principal component analyses revealed proteomic patterns that distinguished inflamed from noninflamed tissues independent of therapy. Gene ontology revealed that proteins downregulated in inflammation are associated with metabolism, whereas upregulated proteins contribute to protein processing. A comparison of pre- and post-treatment proteomes from CD patients identified over 100 proteins that are significantly different between patients who responded and those who did not respond to therapy, including creatine kinase B and basigin.
Assuntos
Colite Ulcerativa , Doença de Crohn , Doenças Inflamatórias Intestinais , Biópsia , Criança , Colite Ulcerativa/diagnóstico , Colite Ulcerativa/tratamento farmacológico , Colo , Doença de Crohn/diagnóstico , Doença de Crohn/tratamento farmacológico , Humanos , Doenças Inflamatórias Intestinais/diagnóstico , Doenças Inflamatórias Intestinais/tratamento farmacológico , Doenças Inflamatórias Intestinais/genética , Mucosa Intestinal , ProteômicaRESUMO
Lysine acetylation (Kac), an abundant post-translational modification (PTM) in prokaryotes, regulates various microbial metabolic pathways. However, no studies have examined protein Kac at the microbiome level, and it remains unknown whether Kac level is altered in patient microbiomes. Herein, we use a peptide immuno-affinity enrichment strategy coupled with mass spectrometry to characterize protein Kac in the microbiome, which successfully identifies 35,200 Kac peptides from microbial or human proteins in gut microbiome samples. We demonstrate that Kac is widely distributed in gut microbial metabolic pathways, including anaerobic fermentation to generate short-chain fatty acids. Applying to the analyses of microbiomes of patients with Crohn's disease identifies 52 host and 136 microbial protein Kac sites that are differentially abundant in disease versus controls. This microbiome-wide acetylomic approach aids in advancing functional microbiome research.
Assuntos
Doença de Crohn/metabolismo , Microbioma Gastrointestinal/fisiologia , Lisina/metabolismo , Acetilação , Voluntários Saudáveis , Humanos , Análise Multivariada , Proteômica , Espectrometria de Massas em TandemRESUMO
Muscle-enriched lamin-interacting protein (Mlip) is an alternatively spliced gene whose splicing specificity is dictated by tissue type. MLIP is most abundantly expressed in brain, cardiac, and skeletal muscle. In the present study, we systematically mapped the transcriptional start and stop sites of murine Mlip Rapid amplification of cDNA ends (RACE) of Mlip transcripts from the brain, heart, and skeletal muscle revealed two transcriptional start sites (TSSs), exon 1a and exon 1b, and only one transcriptional termination site. RT-PCR analysis of the usage of the two identified TSSs revealed that the heart utilizes only exon 1a for MLIP expression, whereas the brain exclusively uses exon 1b TSS. Loss of Mlip exon 1a in mice resulted in a 7-fold increase in the prevalence of centralized nuclei in muscle fibers with the Mlip exon1a-deficient satellite cells on single fibers exhibiting a significant delay in commitment to a MYOD-positive phenotype. Furthermore, we demonstrate that the A-type lamin-binding domain in MLIP is encoded in exon 1a, indicating that MLIP isoforms generated with exon 1b TSS lack the A-type lamin-binding domain. Collectively these findings suggest that Mlip tissue-specific expression and alternative splicing play a critical role in determining MLIP's functions in mice.
Assuntos
Processamento Alternativo/genética , Proteínas de Transporte/genética , Regulação da Expressão Gênica/genética , Proteínas Nucleares/genética , Sítio de Iniciação de Transcrição , Sequência de Aminoácidos , Proteínas de Transporte/química , Proteínas de Transporte/metabolismo , Linhagem Celular , Proteínas Correpressoras , Éxons/genética , Humanos , Íntrons/genética , Proteínas Nucleares/química , Proteínas Nucleares/metabolismo , Especificidade de Órgãos , Isoformas de Proteínas/química , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismoRESUMO
Alterations in gut microbiota have been implicated in the pathogenesis of inflammatory bowel disease (IBD), however factors that mediate the host-microbiota interactions remain largely unknown. Here we collected mucosal-luminal interface samples from a pediatric IBD inception cohort and characterized both the human and microbiota proteins using metaproteomics. We show that microbial proteins related to oxidative stress responses are upregulated in IBD cases compared to controls. In particular, we demonstrate that the expression of human proteins related to oxidative antimicrobial activities is increased in IBD cases and correlates with the alteration of microbial functions. Additionally, we reveal that many of these human proteins are present and show altered abundance in isolated free extracellular vesicles (EVs). Therefore, our study suggests that the alteration of intestinal EV proteomes is associated with the aberrant host-microbiota interactions in IBD.
Assuntos
Colite Ulcerativa/metabolismo , Doença de Crohn/metabolismo , Intestinos/patologia , Microbiota , Proteômica/métodos , Adolescente , Criança , Colite Ulcerativa/patologia , Biologia Computacional , Doença de Crohn/patologia , Cisteína/química , Dano ao DNA , Vesículas Extracelulares/metabolismo , Faecalibacterium prausnitzii , Fezes , Feminino , Microbioma Gastrointestinal , Humanos , Masculino , Espectrometria de Massas , Estresse Oxidativo , ProteomaRESUMO
OBJECTIVE: Improved biomarkers are an unmet clinical need for suspected inflammatory bowel disease (IBD). Need is greatest for children, since current biomarkers suffers from low specificity, particularly in this population; thus, invasive testing methods, with the accompanying risk of complications, are necessary. Additionally, current biomarkers do not delineate disease extent assessment for ulcerative colitis (UC), a factor involved in therapeutic decisions. METHODS: Intestinal mucosal-luminal interface (MLI) aspirates from the ascending colon (AC) and descending colon (DC) were collected during diagnostic colonoscopy from treatment-naïve children. The MLI proteomes of 18 non-IBD and 42 IBD patients were analyzed by liquid chromatography mass spectrometry. Analyses of proteomic data generated protein panels distinguishing IBD from non-IBD and pancolitis from non-pancolitis (UC disease extent). Select protein biomarkers were evaluated in stool samples by enzyme-linked immunosorbent assay (n = 24). RESULTS: A panel of four proteins discriminated active IBD from non-IBD (discovery cohort) with a sensitivity of 0.954 (95% confidence interval (CI): 0.772-0.999) and >0.999 (95% CI: 0.824-1.00) for the AC and DC, respectively, and a specificity of >0.999 (AC, 95% CI: 0.815-1.00; DC, 95% CI:0.692-1.00) for both the AC and DC. A separate panel of four proteins distinguished pancolitis from non-pancolitis in UC patients with sensitivity >0.999 (95% CI: 0.590-1.00) and specificity >0.999 (95% CI: 0.715-1.00). Catalase (p < 0.0001) and LTA4H (p = 0.0002) were elevated in IBD stool samples compared to non-IBD stool samples. CONCLUSION: This study identified panels of proteins that have significantly different expression levels and contribute to accurate IBD diagnosis and disease extent characterization in children with UC. Biomarkers identified from the MLI demonstrate transferable results in stool samples.
Assuntos
Colite Ulcerativa/diagnóstico , Mucosa Intestinal/patologia , Adolescente , Biomarcadores/metabolismo , Catalase/metabolismo , Criança , Colite Ulcerativa/patologia , Colo Ascendente/patologia , Colo Descendente/patologia , Colonoscopia , Ensaio de Imunoadsorção Enzimática , Epóxido Hidrolases/metabolismo , Fezes/química , Feminino , Humanos , Masculino , Proteômica/métodos , Sensibilidade e EspecificidadeRESUMO
OBJECTIVE: Accurate differentiation between Crohn's disease (CD) and UC is important to ensure early and appropriate therapeutic intervention. We sought to identify proteins that enable differentiation between CD and UC in children with new onset IBD. DESIGN: Mucosal biopsies were obtained from children undergoing baseline diagnostic endoscopy prior to therapeutic interventions. Using a super-stable isotope labeling with amino acids in cell culture (SILAC)-based approach, the proteomes of 99 paediatric control and biopsies of patients with CD and UC were compared. Multivariate analysis of a subset of these (n=50) was applied to identify novel biomarkers, which were validated in a second subset (n=49). RESULTS: In the discovery cohort, a panel of five proteins was sufficient to distinguish control from IBD-affected tissue biopsies with an AUC of 1.0 (95% CI 0.99 to 1.0); a second panel of 12 proteins segregated inflamed CD from UC within an AUC of 0.95 (95% CI 0.86 to 1.0). Application of the two panels to the validation cohort resulted in accurate classification of 95.9% (IBD from control) and 80% (CD from UC) of patients. 116 proteins were identified to have correlation with the severity of disease, four of which were components of the two panels, including visfatin and metallothionein-2. CONCLUSIONS: This study has identified two panels of candidate biomarkers for the diagnosis of IBD and the differentiation of IBD subtypes to guide appropriate therapeutic interventions in paediatric patients.
Assuntos
Colite Ulcerativa , Colo Ascendente , Doença de Crohn , Subunidade beta da Proteína Mitocondrial Trifuncional/análise , Nicotinamida Fosforribosiltransferase/análise , Proteômica/métodos , Adolescente , Biomarcadores/análise , Biópsia/métodos , Canadá , Colite Ulcerativa/diagnóstico , Colite Ulcerativa/metabolismo , Colite Ulcerativa/patologia , Colo Ascendente/metabolismo , Colo Ascendente/patologia , Doença de Crohn/diagnóstico , Doença de Crohn/metabolismo , Doença de Crohn/patologia , Estudos Transversais , Diagnóstico Diferencial , Intervenção Médica Precoce , Feminino , Humanos , Masculino , Seleção de PacientesRESUMO
Intestinal microbial dysbiosis is associated with Crohn's disease (CD). However, the mechanisms leading to the chronic mucosal inflammation that characterizes this disease remain unclear. In this report, we use systems-level approaches to study the interactions between the gut microbiota and host in new-onset paediatric patients to evaluate causality and mechanisms of disease. We report an altered host proteome in CD patients indicative of impaired mitochondrial functions. In particular, mitochondrial proteins implicated in H2S detoxification are downregulated, while the relative abundance of H2S microbial producers is increased. Network correlation analysis reveals that Atopobium parvulum controls the central hub of H2S producers. A. parvulum induces pancolitis in colitis-susceptible interleukin-10-deficient mice and this phenotype requires the presence of the intestinal microbiota. Administrating the H2S scavenger bismuth mitigates A. parvulum-induced colitis in vivo. This study reveals that host-microbiota interactions are disturbed in CD and thus provides mechanistic insights into CD pathogenesis.
Assuntos
Bactérias/genética , Doença de Crohn/microbiologia , Microbioma Gastrointestinal , Adolescente , Animais , Bactérias/classificação , Bactérias/isolamento & purificação , Criança , Pré-Escolar , Feminino , Vida Livre de Germes , Humanos , Interleucina-10/genética , Interleucina-10/metabolismo , Masculino , Camundongos , Camundongos Knockout , FilogeniaRESUMO
BACKGROUND: The gut microbiota has been shown to be closely associated with human health and disease. While next-generation sequencing can be readily used to profile the microbiota taxonomy and metabolic potential, metaproteomics is better suited for deciphering microbial biological activities. However, the application of gut metaproteomics has largely been limited due to the low efficiency of protein identification. Thus, a high-performance and easy-to-implement gut metaproteomic approach is required. RESULTS: In this study, we developed a high-performance and universal workflow for gut metaproteome identification and quantification (named MetaPro-IQ) by using the close-to-complete human or mouse gut microbial gene catalog as database and an iterative database search strategy. An average of 38 and 33 % of the acquired tandem mass spectrometry (MS) spectra was confidently identified for the studied mouse stool and human mucosal-luminal interface samples, respectively. In total, we accurately quantified 30,749 protein groups for the mouse metaproteome and 19,011 protein groups for the human metaproteome. Moreover, the MetaPro-IQ approach enabled comparable identifications with the matched metagenome database search strategy that is widely used but needs prior metagenomic sequencing. The response of gut microbiota to high-fat diet in mice was then assessed, which showed distinct metaproteome patterns for high-fat-fed mice and identified 849 proteins as significant responders to high-fat feeding in comparison to low-fat feeding. CONCLUSIONS: We present MetaPro-IQ, a metaproteomic approach for highly efficient intestinal microbial protein identification and quantification, which functions as a universal workflow for metaproteomic studies, and will thus facilitate the application of metaproteomics for better understanding the functions of gut microbiota in health and disease.
Assuntos
Bactérias/classificação , Microbioma Gastrointestinal , Metagenômica/métodos , Proteômica/métodos , Animais , Bactérias/metabolismo , Proteínas de Bactérias/metabolismo , Biologia Computacional/métodos , Bases de Dados Genéticas , Dieta Hiperlipídica , Microbioma Gastrointestinal/efeitos dos fármacos , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Humanos , Camundongos , Espectrometria de Massas em TandemRESUMO
Intestinal microbiota is emerging as one of the key environmental factors influencing or causing the development of numerous human diseases. Metaproteomics can provide invaluable information on the functional activities of intestinal microbiota and on host-microbe interactions as well. However, the application of metaproteomics in human microbiota studies is still largely limited, in part due to the lack of accurate quantitative intestinal metaproteomic methods. Most current metaproteomic microbiota studies are based on label-free quantification, which may suffer from variability during the separate sample processing and mass spectrometry runs. In this study, we describe a quantitative metaproteomic strategy, using in vitro stable isotopically ((15)N) labeled microbiota as a spike-in reference, to study the intestinal metaproteomes. We showed that the human microbiota were efficiently labeled (>95% (15)N enrichment) within 3 days under in vitro conditions, and accurate light-to-heavy protein/peptide ratio measurements were obtained using a high-resolution mass spectrometer and the quantitative proteomic software tool Census. We subsequently employed our approach to study the in vitro modulating effects of fructo-oligosaccharide and five different monosaccharides on the microbiota. Our methodology improves the accuracy of quantitative intestinal metaproteomics, which would promote the application of proteomics for functional studies of intestinal microbiota.
Assuntos
Intestinos/microbiologia , Microbiota , Proteômica , Cromatografia Líquida de Alta Pressão , Bases de Dados Factuais , Fucose/metabolismo , Humanos , Mucosa Intestinal/metabolismo , Marcação por Isótopo , Isótopos de Nitrogênio/química , Peptídeos/análise , Peptídeos/química , Análise de Componente Principal , Proteínas/análise , Proteínas/química , Espectrometria de Massas em TandemRESUMO
Mutations in the A-type lamin (LMNA) gene are associated with age-associated degenerative disorders of mesenchymal tissues, such as dilated cardiomyopathy, Emery-Dreifuss muscular dystrophy, and limb-girdle muscular dystrophy. The molecular mechanisms that connect mutations in LMNA with different human diseases are poorly understood. Here, we report the identification of a Muscle-enriched A-type Lamin-interacting Protein, MLIP (C6orf142 and 2310046A06rik), a unique single copy gene that is an innovation of amniotes (reptiles, birds, and mammals). MLIP encodes alternatively spliced variants (23-57 kDa) and possesses several novel structural motifs not found in other proteins. MLIP is expressed ubiquitously and most abundantly in heart, skeletal, and smooth muscle. MLIP interacts directly and co-localizes with lamin A and C in the nuclear envelope. MLIP also co-localizes with promyelocytic leukemia (PML) bodies within the nucleus. PML, like MLIP, is only found in amniotes, suggesting that a functional link between the nuclear envelope and PML bodies may exist through MLIP. Down-regulation of lamin A/C expression by shRNA results in the up-regulation and mislocalization of MLIP. Given that MLIP is expressed most highly in striated and smooth muscle, it is likely to contribute to the mesenchymal phenotypes of laminopathies.
Assuntos
Processamento Alternativo/fisiologia , Proteínas de Transporte/biossíntese , Regulação da Expressão Gênica/fisiologia , Lamina Tipo A/metabolismo , Proteínas Musculares/biossíntese , Músculos/metabolismo , Membrana Nuclear/metabolismo , Proteínas Nucleares/biossíntese , Animais , Proteínas de Transporte/genética , Proteínas Correpressoras , Humanos , Lamina Tipo A/genética , Camundongos , Proteínas Musculares/genética , Músculos/citologia , Membrana Nuclear/genética , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Especificidade de Órgãos , Proteína da Leucemia Promielocítica , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Proteínas Supressoras de Tumor/genética , Proteínas Supressoras de Tumor/metabolismoRESUMO
We sought to identify an essential component of the TEAD4/VGLL4 transcription factor complex that controls vascular endothelial growth factor A (VEGFA) expression in muscle. A yeast 2-hybrid screen was used to clone a novel component of the TEAD4 complex from a human heart cDNA library. We identified interferon response factor 2 binding protein 2 (IRF2BP2) and confirmed its presence in the TEAD4/VGLL4 complex in vivo by coimmunoprecipitation and mammalian 2-hybrid assays. Coexpression of IRF2BP2 with TEAD4/VGLL4 or TEAD1 alone potently activated, whereas knockdown of IRF2BP2 reduced, VEGFA expression in C(2)C(12) muscle cells. Thus, IRF2BP2 is required to activate VEGFA expression. In mouse embryos, IRF2BP2 was ubiquitously expressed but became progressively enriched in the fetal heart, skeletal muscles, and lung. Northern blot analysis revealed high levels of IRF2BP2 mRNA in adult human heart and skeletal muscles, but immunoblot analysis showed low levels of IRF2BP2 protein in skeletal muscle, indicating post-transcriptional regulation of IRF2BP2 expression. IRF2BP2 protein levels are markedly increased by ischemia in skeletal and cardiac muscle compared to normoxic controls. IRF2BP2 is a novel ischemia-induced coactivator of VEGFA expression that may contribute to revascularization of ischemic cardiac and skeletal muscles.