APPLIED QUANTITATIVE PROTEOMICS ANALYSIS

En esta tesis se ha aplicado el estado del arte en análisis cuantitativo en proteómica. Los datos analizados en este trabajo, provenientes de tres proyectos distintos, fueron obtenidos usando tres de las técnicas más utilizadas en proteómica: cuantificación label-free, marcaje isobárico y SWATH. Los resultados obtenidos en los diferentes proyectos son también interpretados mediante múltiples herramientas bioinformáticas. La cuantificación label-free es utilizada aquí para obtener la combinación óptima de software y parámetros usando un conjunto de datos públicos. El marcaje isobárico, usando TMT, se emplea en el estudio de los diferentes perfiles de expresión proteica, obtenidos con dos modelos de hipoxia de diferente severidad en cerebros de rata. La técnica SWATH se busca en la búsqueda de biomarcadores de síndorme de ovario poliquístico en plasma. Por último, los elementos necesarios para la implantación de una plataforma de análisis proteómica , en términos de software y hardware, se describen en forma detallada. In this thesis, the state of the art in quantitative proteomics analysis has been applied. The data analyzed in this work, coming from three different projects, were acquired using three of the most used techniques in proteomics: label-free, isobaric labeling and SWATH. The results obtained in the different projects are also interpreted using multiple bioinformatics tools. The label-free quantization is used here to asses the optimal combination of software and parameters using a public data set. Isobaric labeling, using TMT, is employed to study the different profiles in protein expression when two hypoxic models, with different severity, are applied in rat brains. The SWATH technique is used in the search of biomarkers for polycystic ovary syndrome in plasma. Finally, the elements required for setting up a platform for proteomics analysis, both in terms of hardware and software, are comprehensively described.Tesis Univ. Jaén. Departamento de Biología Experimenta

Quantitative proteomics analysis of chondrogenic differentiation of mesenchymal stem cells by SILAC

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The Al-induced proteomes of epidermal and outer cortical cells in root apex of cherry tomato \u27LA 2710\u27

This paper reports a laser capture microdissection-tandem mass tag-quantitative proteomics analysis of Al-sensitive cells in root tips. Cherry tomato (Solanum lycopersicum var. cerasiforme ‘LA2710’) seedlings were treated under 15 μM Al3+ activity for 13 d. Root-tip longitudinal fresh frozen tissue sections of 10 μm thickness were prepared. The Al-sensitive root zone and cells were determined using histochemical analysis of root-tips and micro-sections. A procedure for collecting the Al-sensitive cells using laser capture microdissection-protein extraction-tandem mass tag-proteomics analysis was developed. Proteomics analysis of 18 μg protein/sample with three biological replicates per treatment condition identified 3879 quantifiable proteins each associated with two or more unique peptides. Quantified proteins constituted a broad range of Kyoto Encyclopedia of Genes and Genomes pathways when searched in the annotated tomato genome. Differentially expressed proteins between the Al-treated and non-Al treated control conditions were identified, including 128 Al-up-regulated and 32 Al-down-regulated proteins. Analysis of functional pathways and protein-protein interaction networks showed that the Al-down-regulated proteins are involved in transcription and translation, and the Al-up-regulated proteins are associated with antioxidant and detoxification and protein quality control processes. The proteomics data are available via ProteomeXchange with identifier PXD010459 under project title ‘LCM-quantitative proteomics analysis of Al-sensitive tomato root cells’. Significance This paper presents an efficient laser capture microdissection-tandem mass tag-quantitative proteomics analysis platform for the analysis of Al sensitive root cells. The analytical procedure has a broad application for proteomics analysis of spatially separated cells from complex tissues. This study has provided a comprehensive proteomics dataset expressed in the epidermal and outer-cortical cells at root-tip transition zone of Al-treated tomato seedlings. The proteomes from the Al-sensitive root cells are valuable resources for understanding and improving Al tolerance in plants

Analysis of the hippocampal proteome in ME7 prion disease reveals a predominant astrocytic signature and highlights the brain-restricted production of clusterin in chronic neurodegeneration

Prion diseases are characterized by accumulation of misfolded protein, gliosis, synaptic dysfunction, and ultimately neuronal loss. This sequence, mirroring key features of Alzheimer disease, is modeled well in ME7 prion disease. We used iTRAQ(TM)/mass spectrometry to compare the hippocampal proteome in control and late-stage ME7 animals. The observed changes associated with reactive glia highlighted some specific proteins that dominate the proteome in late-stage disease. Four of the up-regulated proteins (GFAP, high affinity glutamate transporter (EAAT-2), apo-J (Clusterin), and peroxiredoxin-6) are selectively expressed in astrocytes, but astrocyte proliferation does not contribute to their up-regulation. The known functional role of these proteins suggests this response acts against protein misfolding, excitotoxicity, and neurotoxic reactive oxygen species. A recent convergence of genome-wide association studies and the peripheral measurement of circulating levels of acute phase proteins have focused attention on Clusterin as a modifier of late-stage Alzheimer disease and a biomarker for advanced neurodegeneration. Since ME7 animals allow independent measurement of acute phase proteins in the brain and circulation, we extended our investigation to address whether changes in the brain proteome are detectable in blood. We found no difference in the circulating levels of Clusterin in late-stage prion disease when animals will show behavioral decline, accumulation of misfolded protein, and dramatic synaptic and neuronal loss. This does not preclude an important role of Clusterin in late-stage disease, but it cautions against the assumption that brain levels provide a surrogate peripheral measure for the progression of brain degeneration

Quantitative Proteomics Analysis of Differentially Expressed Proteins in Aβ(17-42) Treated Synaptosomes

Oxidative stress has been associated in the pathogenesis of numerous diseases such as neurodegenerative disorders, ischemia, and cancer. The brain is susceptible to oxidative stress due to its high content of peroxidizable unsaturated fatty acids, high consumption of oxygen per unit weight, high levels of free radicals, and comparatively low levels of antioxidant defense systems. Reactive oxygen species (ROS) and reactive nitrogen species (RNS) can react with biomolecules such as proteins, lipids, carbohydrates, DNA, and RNA, which can lead to oxidative damage, cellular dysfunction, and can ultimately cause cell death. Down syndrome (DS) is the most common form of chromosomal abnormality found in live-born infants. DS patients have an extensive deposition of Aβ(17-42) peptide, which could contribute to their increased rate of developing Alzheimer\u27s disease (AD). Since AD cannot be properly diagnosed until autopsy, development of a novel Down syndrome model using Aβ(17-42) could be beneficial in determining oxidative stress levels and their relationship to mild cognitive impairment (MCI), the earliest form of AD in order to possibly be used as a diagnostic tool for AD. We have found a significant difference between oxidative stress levels in Aβ(17-42) treated synaptosomes and control. By using proteomics, we have also identified several biomarkers including aldehyde dehydrogenase, aldolase, α-enolase, heat shock cognate 71, peptidyl-prolyl cis-trans isomerase, and ATP synthase α chain. Our present findings, suggest the role of Aβ(17-42) as one of the contributing factors in mediating oxidative stress in DS, and AD brain leading to neurodegeneration

Quantitative proteomics analysis of CaMKII phosphorylation and the CaMKII interactome in the mouse forebrain

Ca(2+)/calmodulin-dependent protein kinase IIα (CaMKIIα) autophosphorylation at Thr286 and Thr305/Thr306 regulates kinase activity and modulates subcellular targeting and is critical for normal synaptic plasticity and learning and memory. Here, a mass spectrometry-based approach was used to identify Ca(2+)-dependent and -independent in vitro autophosphorylation sites in recombinant CaMKIIα and CaMKIIβ. CaMKII holoenzymes were then immunoprecipitated from subcellular fractions of forebrains isolated from either wild-type (WT) mice or mice with a Thr286 to Ala knock-in mutation of CaMKIIα (T286A-KI mice) and analyzed using the same approach in order to characterize in vivo phosphorylation sites in both CaMKII isoforms and identify CaMKII-associated proteins (CaMKAPs). A total of six and seven autophosphorylation sites in CaMKIIα and CaMKIIβ, respectively, were detected in WT mice. Thr286-phosphorylated CaMKIIα and Thr287-phosphorylated CaMKIIβ were selectively enriched in WT Triton-insoluble (synaptic) fractions compared to Triton-soluble (membrane) and cytosolic fractions. In contrast, Thr306-phosphorylated CaMKIIα and Ser315- and Thr320/Thr321-phosphorylated CaMKIIβ were selectively enriched in WT cytosolic fractions. The T286A-KI mutation significantly reduced levels of phosphorylation of CaMKIIα at Ser275 across all subcellular fractions and of cytosolic CaMKIIβ at Ser315 and Thr320/Thr321. Significantly more CaMKAPs coprecipitated with WT CaMKII holoenzymes in the synaptic fraction compared to that in the membrane fraction, with functions including scaffolding, microtubule organization, actin organization, ribosomal function, vesicle trafficking, and others. The T286A-KI mutation altered the interactions of multiple CaMKAPs with CaMKII, including several proteins linked to autism spectrum disorders. These data identify CaMKII isoform phosphorylation sites and a network of synaptic protein interactions that are sensitive to the abrogation of Thr286 autophosphorylation of CaMKIIα, likely contributing to the diverse synaptic and behavioral deficits of T286A-KI mice

Quantitative Proteomics Analysis of Maternal Plasma in Down Syndrome Pregnancies Using Isobaric Tagging Reagent (iTRAQ)

Currently no specific biomarkers exist for the screening of pregnancies at risk for down syndrome (DS). Since a quantitative proteomic approach with isobaric labelling (iTRAQ) has recently been suggested to be highly suitable for the discovery of novel plasma biomarkers, we have now used this method to examine for potential quantitative changes in the plasma proteome of the pregnancies bearing DS fetuses in comparison to normal healthy babies. In our study, we used plasma from six women with DS pregnancies and six with uncomplicated pregnancies care were taken to match cases and controls for gestational and maternal age, as these could be a confounder. In our quantitative proteomics analysis we were able to detect 178 proteins using iTRAQ labelling in conjunction with 4800 MALDI TOF/TOF. Amongst these we observed changes in βHCG, a known screening marker for DS, indicating that our assay was functional. We found a number of elevated proteins Ig lambda chain C region, serum amyloid P-component, amyloid beta A4, and under expressed proteins like gamma-actin and titin in DS pregnancies. These proteins are also found in the sera of patients with Alzheimer disease, which share similar pathologies of DS. Our study therefore indicates that the iTRAQ labelling approach may be indeed useful for the detection of novel biomarkers

iTRAQ-based quantitative proteomics analysis identifies host pathways modulated during toxoplasma gondii infection in swine

Toxoplasma gondii is a leading cause of foodborne illness and consumption of undercooked pig meat is a major risk factor for acquiring toxoplasmosis, which causes a substantial burden on society. Here, we used isobaric tags for relative and absolute quantification (iTRAQ) labelling coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS) to identify cellular proteins and pathways altered during T. gondii infection in pigs. We also used parallel reaction monitoring-based LC-MS/MS to verify the levels of protein expression of infected spleens and mesenteric lymph nodes (MLNs). At 6 days post-infection (dpi), 156, 391, 170, 292, and 200 differentially expressed proteins (DEPs) were detected in the brain, liver, lung, MLNs and spleen, respectively. At 18 dpi, 339, 351, 483, 388, and 303 DEPs were detected in the brain, liver, lung, MLNs and spleen, respectively. Although proteins involved in immune responses were upregulated in all infected tissues, protein expression signature in infected livers was dominated by downregulation of the metabolic processes. By weighted gene co-expression network analysis, we could further show that all proteins were clustered into 25 co-expression modules and that the pink module significantly correlated with the infection status. We also identified 163 potential anti-T. gondii proteins (PATPs) and provided evidence that two PATPs (HSP70.2 and PDIA3) can reduce T. gondii burden in porcine macrophages in vitro. This comprehensive proteomics analysis reveals new facets in the pathogenesis of T. gondii infection and identifies key proteins that may contribute to the pig’s defense against this infection

SETD3 is an actin histidine methyltransferase that prevents primary dystocia.

For more than 50 years, the methylation of mammalian actin at histidine 73 has been known to occur1. Despite the pervasiveness of His73 methylation, which we find is conserved in several model animals and plants, its function remains unclear and the enzyme that generates this modification is unknown. Here we identify SET domain protein 3 (SETD3) as the physiological actin His73 methyltransferase. Structural studies reveal that an extensive network of interactions clamps the actin peptide onto the surface of SETD3 to orient His73 correctly within the catalytic pocket and to facilitate methyl transfer. His73 methylation reduces the nucleotide-exchange rate on actin monomers and modestly accelerates the assembly of actin filaments. Mice that lack SETD3 show complete loss of actin His73 methylation in several tissues, and quantitative proteomics analysis shows that actin His73 methylation is the only detectable physiological substrate of SETD3. SETD3-deficient female mice have severely decreased litter sizes owing to primary maternal dystocia that is refractory to ecbolic induction agents. Furthermore, depletion of SETD3 impairs signal-induced contraction in primary human uterine smooth muscle cells. Together, our results identify a mammalian histidine methyltransferase and uncover a pivotal role for SETD3 and actin His73 methylation in the regulation of smooth muscle contractility. Our data also support the broader hypothesis that protein histidine methylation acts as a common regulatory mechanism