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Results for “targeted proteomic analysis”

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PubMed2007

Immunoaffinity purification of plasma membrane with secondary antibody superparamagnetic beads for proteomic analysis.

Plasma membrane (PM) has very important roles in cell-cell interaction and signal transduction, and it has been extensively targeted for drug design. A major prerequisite for the analysis of PM proteome is the preparation of PM with high purity. Density gradient centrifugation has been commonly employed to isolate PM, but it often occurred with contamination of internal membrane. Here we describe a method for plasma membrane purification using second antibody superparamagnetic beads that combines subcellular fractionation and immunoisolation strategies. Four methods of immunoaffinity were compared, and the variation of crude plasma membrane (CPM), superparamagnetic beads, and antibodies was studied. The optimized method and the number of CPM, beads, and antibodies suitable for proteome analysis were obtained. The PM of mouse liver was enriched 3-fold in comparison with the density gradient centrifugation method, and contamination from mitochondria was reduced 2-fold. The PM protein bands were extracted and trypsin-digested, and the resulting peptides were resolved and characterized by MALDI-TOF-TOF and ESI-Q-TOF, respectively. Mascot software was used to analyze the data against IPI-mouse protein database. Nonredundant proteins (248) were identified, of which 67% are PM or PM-related proteins. No endoplasmic reticulum (ER) or nuclear proteins were identified according to the GO annotation in the optimized method. Our protocol represents a simple, economic, and reproducible tool for the proteomic characterization of liver plasma membrane.

Animals↗

PubMed2006

Proteome analysis of cultured fibroblasts from type 1 diabetic patients and normal subjects.

CONTEXT: Protein profiling of diabetic tissues could provide useful biomarkers for early diagnosis, therapeutic targets, and disease response markers. Cultured fibroblasts are a useful in vitro model for proteome analysis and study of the molecular mechanisms involved in diabetes. OBJECTIVE: The objective of the study was to isolate and characterize the proteins of cultured fibroblasts, obtained by skin biopsy, from long-term type 1 diabetic patients without complications and age- and sex-matched normal subjects as controls. DESIGN: Proteins were separated by two-dimensional electrophoresis (2-DE), and the gel images were qualitatively and quantitatively analyzed. Protein identification was performed by matrix-assisted laser desorption/ionization mass spectrometry. RESULTS: Reproducible protein maps of fibroblasts from diabetic and healthy subjects were obtained. A total of 125 protein spots were isolated and identified, among them 27 proteins not previously reported in published human fibroblast 2-DE maps, including 20 proteins never reported previously in the literature in human skin fibroblasts. Quantitative analyses revealed six protein spots differentially expressed in the fibroblasts from the diabetic vs. the control subjects (P < 0.05), representing glycolytic enzymes and structural proteins. An increase of triosephosphate I isomerase of two splice isoforms of pyruvate kinase and alpha-actinin 4 and a decrease of tubulin-beta2 and splice isoform 2 of tropomyosin beta-chain were detected. CONCLUSIONS: We generated 2-DE reference maps of the proteome of human skin fibroblasts from both normal and uncomplicated type 1 diabetic patients. Differences in glycolytic enzymes and structural proteins were found. The functional implications of the identified proteins are discussed.

Adult↗

PubMed2005

Limitations of current proteomics technologies.

Application of proteomics technologies in the investigation of biological systems creates new possibilities in the elucidation of biopathomechanisms and the discovery of novel drug targets and early disease markers. A proteomic analysis involves protein separation and protein identification as well as characterization of the post-translational modifications. Proteomics has been applied in the investigation of various disorders, like neurological diseases, and the application has resulted in the detection of a large number of differences in the levels and the modifications of proteins between healthy and diseased states. However, the current proteomics technologies are still under development and show certain limitations. In this article, we discuss the major drawbacks and pitfalls of proteomics we have observed in our laboratory and in particular during the application of proteomics technologies in the investigation of the brain.

Chromatography, Liquid↗

PubMed2004

bFGF rescues 423-cells from serum starvation-induced apoptosis downstream of activated caspase-3.

Serum withdrawal rapidly induces apoptosis in rat 423-cells, while addition of bFGF results in cell survival. However, surviving cells initially display morphological changes characteristic for apoptotic cells and even process caspases. Active caspase-3 was detected at the single-cell level in those finally bFGF-rescued cells, while mitochondrial integrity was maintained. Generation of cleavage products of caspase targets was confirmed in surviving cells. Proteome analysis indicated multi-faceted survival activities of bFGF including upregulation of inhibitor-of-apoptosis and heat shock protein family members directly interfering with caspases. Our data suggest that the "point-of-no-return" in death-induced cells has to be moved downstream of activated caspase-3.

Animals↗

PubMed2006

Mechanisms of disease: Preclinical reports of antineoplastic synergistic action of bisphosphonates.

For patients with malignant bone disease, bisphosphonate therapy is the standard treatment. Preclinical and preliminary clinical data suggest that bisphosphonates have direct or indirect antitumor effects: they affect growth-factor release, cancer-cell adhesion, invasion and viability, angiogenesis, and apoptosis of cancer cells. These effects might be enhanced through co-administration with chemotherapy agents, biological agents, or both. We survey the biochemical pathways and molecular targets of bisphosphonates, and discuss the molecular mechanisms of these antitumor effects, as well as the documented antineoplastic preclinical effects of bisphosphonates used in combination with cytotoxic and biological drugs. Moreover, the positive interactions between bisphosphonates and farnesyltransferase inhibitors, KIT receptor tyrosine kinase inhibitors (e.g. imatinib mesylate) and cyclo-oxygenase-2 inhibitors are discussed in relation to their potential synergistic and additive effects. We briefly discuss identification of new molecular targets of bisphosphonates from genomic and proteomic analysis, and highlight the cellular consequences of drug-related enzyme inhibition.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed2026

TNFα-induced endothelial extracellular vesicles regulate astrocyte function: an integrated transcriptomic and proteomic study.

Endothelial cells and astrocytes are critical structural and functional components of the blood-brain barrier. In many neuroinflammatory diseases, endothelial cells are among the first to respond to inflammatory stimuli and release extracellular vesicles (EVs). However, whether inflammatory stimulation alters EV RNA cargo and subsequently regulates astrocyte function remains unclear. In this study, we performed integrated RNA sequencing and proteomic analyses to investigate the effects of TNFα-stimulated endothelial EVs on astrocytes. RNA profiling revealed significant alterations in EV cargo after TNFα stimulation, including 867 upregulated and 577 downregulated mRNAs, 317 upregulated and 15 downregulated lncRNAs, and 88 upregulated and 62 downregulated miRNAs. The results of functional enrichment analysis suggested that altered EV RNAs may primarily promote inflammatory responses, cell migration, and RNA splicing in astrocytes while reducing their regulatory effects on neuronal projection and calcium homeostasis. Further integrative analysis of EV RNAs and astrocytic proteomics revealed key overlapping targets, including upregulated expression of ICAM1, SOD2, TFPI2, and TNFAIP8, whereas NFKBIA expression was consistently decreased. Network analysis revealed NF-κB as the central regulatory node. Reduced levels of EV-derived NFKBIA mRNA were associated with decreased IκBα protein levels in astrocytes, which promoted NF-κB activation and inflammatory cytokine release. Finally, overexpression of IκBα in astrocytes significantly attenuated TNFα EV-induced IL-1β and IL-6 secretion. Collectively, these findings demonstrate that TNFα-stimulated endothelial EVs coordinately regulate astrocyte function through mRNA, lncRNA, and miRNA cargo and that the IκBα/NF-κB axis may be a key mechanism underlying endothelial EV-mediated inflammatory disruption of the blood-brain barrier.

Astrocytes↗

PubMed2006

Antibody microarrays: current status and key technological advances.

Antibody-based microarrays are among the novel classes of rapidly evolving proteomic technologies that holds great promise in biomedicine. Miniaturized microarrays (< 1 cm2) can be printed with thousands of individual antibodies carrying the desired specificities, and with biological sample (e.g., an entire proteome) added, virtually any specifically bound analytes can be detected. While consuming only minute amounts (< microL scale) of reagents, ultra- sensitive assays (zeptomol range) can readily be performed in a highly multiplexed manner. The microarray patterns generated can then be transformed into proteomic maps, or detailed molecular fingerprints, revealing the composition of the proteome. Thus, protein expression profiling and global proteome analysis using this tool will offer new opportunities for drug target and biomarker discovery, disease diagnostics, and insights into disease biology. Adopting the antibody microarray technology platform, several biomedical applications, ranging from focused assays to proteome-scale analysis will be rapidly emerging in the coming years. This review will discuss the current status of the antibody microarray technology focusing on recent technological advances and key issues in the process of evolving the methodology into a high-performing proteomic research tool.

Animals↗

PubMed2005

Genistein blocks homocysteine-induced alterations in the proteome of human endothelial cells.

Dietary isoflavones from soy are suggested to protect endothelial cells from damaging effects of endothelial stressors and thereby to prevent atherosclerosis. In search of the molecular targets of isoflavone action, we analyzed the effects of the major soy isoflavone, genistein, on changes in protein expression levels induced by the endothelial stressor homocysteine (Hcy) in EA.hy 926 endothelial cells. Proteins from cells exposed for 24 h to 25 microM Hcy alone or in combination with 2.5 microM genistein were separated by two-dimensional gel electrophoresis and those with altered spot intensities were identified by peptide mass fingerprinting. Genistein reversed Hcy-induced changes of proteins involved in metabolism, detoxification, and gene regulation; and some of those effects can be linked functionally to the antiatherosclerotic properties of the soy isoflavone. Alterations of steady-state levels of cytoskeletal proteins by genistein suggested an effect on apoptosis. As a matter of fact genistein caused inhibition of Hcy-mediated apoptotic cell death as indicated by inhibition of DNA fragmentation and chromatin condensation. In conclusion, proteome analysis allows the rapid identification of cellular target proteins of genistein action in endothelial cells exposed to the endothelial stressor Hcy and therefore enables the identification of molecular pathways of its antiatherosclerotic action.

Apoptosis↗

PubMed2005

[Proteome analysis of nuclear matrix proteins during arsenic trioxide induced apoptosis in K562 cells].

OBJECTIVE: To investigate arsenic trioxide (As(2)O(3))-target interactions at the level of nuclear matrix (NM) in chronic myelogenous leukemia cell line K562 by proteomics. METHODS: DNA fragmentation analysis was used for As(2)O(3) induced apoptosis of K562 cells. The nuclear matrix proteins were analyzed by high-resolution two-dimensional gel electrophoresis and computer-assisted image analysis. RESULTS: While more than 200 protein spots were shared among the nuclear matrices, about 18 distinct spots were found characteristic of As(2)O(3) treated cells. Onset of mass mange apoptosis, and the profiling of nuclear matrix proteins had been alternated and it was a more sensitive indicator than nucleosomal DNA fragmentation against As(2)O(3) treatment. CONCLUSION: As(2)O(3) induced apoptosis in K562 cells in a dose-time-dependent manner. As(2)O(3) might be clinically useful in treatment of chronic myelogenous leukemia and the changes of nuclear matrix proteins in the treated cells can be used as a useful indicator for the treatment.

Antineoplastic Agents↗

PubMed2026

Proteomic and Phosphoproteomic Signatures Link Molecular Remodeling to Behavioral Outcomes Following Elderberry and DHA Supplementation in Aging Mice.

Background: Aging is a risk factor for Alzheimer's disease and related dementias, which are associated with synaptic dysfunction and cognitive decline. Elderberry (Sambucus spp.) is rich in anthocyanins with antioxidant and anti-inflammatory properties. Docosahexaenoic acid (DHA), an essential fatty acid, plays a key role in neuronal membrane integrity during brain aging. However, it remains unclear whether elderberry and DHA exert overlapping or distinct effects on brain aging and how these relate to molecular signaling. This study aimed to characterize molecular signatures induced by dietary supplementation and to determine their relationships with behavioral outcomes. Methods: 44-week-old male C57BL/6J mice were randomly assigned to control, elderberry, DHA, or combined diets for 12 weeks. Behavioral testing assessed anxiety-like behavior, spatial learning and memory. Brain tissues underwent proteomic and phosphoproteomic profiling and fatty-acid analysis. Data were analyzed using Ingenuity Pathway Analysis to identify enriched pathways, upstream regulators, and functional associations. Results: Elderberry as well as DHA supplementation induced targeted remodeling of the proteome and phosphoproteome, with pathway enrichment involving synaptogenesis, glutamatergic signaling, and long-term potentiation. Upstream-regulator analysis predicted elderberry-associated CDK5 signaling, accompanied by reduced MAPT/Tau phosphorylation at selected sites, whereas DHA supplementation was associated with CAMK-related signaling. DHA supplementation altered fatty-acid composition, increasing the n-3/n-6 ratio. Elderberry reduced anxiety-like behavior and improved target-directed search during the Barnes maze probe test. Molecular signatures were examined in relation to the measured behavioral outcomes. Conclusions: Elderberry and DHA are associated with distinct molecular networks related to synaptic function and behavioral outcomes in the aging male mouse brain. These findings support further investigation of elderberry and DHA as dietary interventions targeting molecular and behavioral features of brain aging.

Animals↗

PubMed2006

Chemical and structural diversity of siRNA molecules.

Short interfering RNAs (siRNAs) are 21-23 nt long double-stranded oligoribonucleotides which in mammalian cells exhibit a potency for sequence-specific gene silencing via an RNA interference (RNAi) pathway. It has been already proven that exogenous, chemically synthesized siRNA molecules are effective inhibitors of gene expression and are widely applied for analysis of protein function and proteomics-based target identification. Moreover, since their discovery siRNA molecules have been implemented as potential candidates for therapeutic applications. Variously modified siRNA molecules containing sugar modifications (2'-OMe, -F, -O-allyl, -amino, orthoesters and LNA analogues), internucleotide phospodiester bond modifications (phosphorothioates, boranophosphates), base modifications (s(2)U) as well as 3'-terminal cholesterol-conjugated constructs were investigated as potential candidates for effective inhibition of gene expression. This chapter reviews an impact of chemical and structural modifications of siRNA molecules on their serum and thermal stability, cellular and in vivo activity, cellular uptake, biodistribution and cytotoxicity. Functional analysis of chemically modified siRNA molecules allows for better understanding of the mechanism of the RNA interference process as well as demonstrates immense efforts in optimizing in vivo potency of siRNA molecules for RNAi-based drug design.

Animals↗

PubMedDate not supplied

Liquid chromatography MALDI MS/MS for membrane proteome analysis.

Membrane proteins play critical roles in many biological functions and are often the molecular targets for drug discovery. However, their analysis presents a special challenge largely due to their highly hydrophobic nature. We present a surfactant-aided shotgun proteomics approach for membrane proteome analysis. In this approach, membrane proteins were solubilized and digested in the presence of SDS followed by newly developed auto-offline liquid chromatography/matrix-assisted laser desorption ionization (LC/MALDI) tandem MS analysis. Because of high tolerance of MALDI to SDS, one-dimensional (1D) LC separation can be combined with MALDI for direct analysis of protein digests containing SDS, without the need for extensive sample cleanup. In addition, the heated droplet interface used in LC/MALDI can work with high flow LC separations, allowing a relatively large amount of protein digest to be used for 1D LC/MALDI which facilitates the detection of low abundance proteins. The proteome identification results obtained by LC/MALDI are compared to the gel electrophoresis/MS method as well as the shotgun proteomics method using 2D LC/electrospray ionization MS. It is demonstrated that, while LC/MALDI provides more extensive proteome coverage compared to the other two methods, these three methods are complementary to each other and a combination of these methods should provide a more comprehensive membrane proteome analysis.

Chromatography, High Pressure Liquid↗

PubMed2006

A screening method for DNA aptamers that bind to a specific, unidentified protein in tissue samples.

Aptamers are oligonucleotide ligands with a high affinity to, and specificity for, various target molecules and they are expected to be powerful tools for proteomic analysis. To select aptamers that bind to a specific unidentified protein in tissues for protein analysis, a screening method was developed using chicken skeletal muscle as a model. Target proteins in the target mixture were separated by electrophoresis and transferred to a membrane, and a DNA library was added onto it. The aptamers that bound to the target protein were visualized by chemiluminescence and collected by cutting out the visualized band. The specific aptamers to the target protein were selected by only one round of selection using this screening, suggesting this screening method might be useful for selecting aptamers for proteome analysis.

Animals↗

PubMed2002

Targeted proteomic profiling of renal Na(+) transporter and channel abundances in angiotensin II type 1a receptor knockout mice.

The renal tubule transporters responsible for Na(+) and water transport along the nephron have been identified and cloned, permitting comprehensive analysis of transporter protein abundance changes in complex physiological models by using a "targeted proteomics" approach. Here, we apply this approach to screen renal homogenates from mice in which the gene for the angiotensin II type 1a (AT(1a)) receptor has been deleted (versus wild-type mice) to determine which sodium transporters and channels are regulated by the AT(1a) receptor at the protein abundance level. In mice maintained on a low NaCl diet (<0.02% NaCl), (1) the abundances of 2 aldosterone-regulated transporters were markedly decreased in knockout versus wild-type mice, namely, the thiazide-sensitive cotransporter and the alpha-subunit of the amiloride-sensitive Na(+) channel (alpha-ENaC); (2) the abundances of beta-ENaC and gamma-ENaC were markedly increased; and (3) there were no significant changes in the abundances of the proximal tubule Na+-H(+) exchanger or the Na(+)-K(+)-2Cl(-) cotransporter of the thick ascending limb. When the experiment was repeated on higher NaCl diets (0.4% or 6% NaCl), the decrease in alpha-ENaC abundance persisted, whereas the other changes were abolished. Analysis of serum aldosterone concentration in AT(1a) knockout mice and wild-type mice on the low NaCl diet revealed the absence of a decrease with AT(1a) gene deletion (11.8 +/- 2.3 nmol/L for knockout mice and 5.7 +/- 0.8 nmol/L for wild-type mice [significantly increased]). These results reveal that the AT(1a) receptor plays an important role in regulation of Na(+) transporter and channel proteins in the "post-macula densa" region of the renal tubule via a mechanism that is not dependent on altered circulating aldosterone concentrations.

Angiotensin II↗

PubMed2004

Proteomic response analysis of endothelial cells of human coronary artery to stimulation with carbachol.

AIM: To identify the molecular basis of the endothelial target for acetylcholine (ETA). METHODS: Proteomic methods were used to monitor changes in protein expression in the first 10 h following the stimulation of human coronary endothelial cells with carbachol 100 micromol/L. Thirty proteins showing the largest changes were identified by mass spectrometry. RESULTS: Based on analysis with Image Master 2-D Elite software, about 623 protein spots were detected in control cells and 825 protein spots in carbachol-treated cells, the matching rate was 68.1 %. Among all the detected spots, 39 were up-regulated and 29 were down-regulated, showing detectable changes varied from 1.7-3.8 folds. Forty one spots in the peptide mass fingerprints were successfully obtained. The most interesting feature was that all the four newly synthesized proteins belonged to the heat shock protein family. CONCLUSION: These identified proteins played key roles in the molecular mechanism of ETA.

Acetylcholine↗

PubMed2005

Flux balance analysis of mycolic acid pathway: targets for anti-tubercular drugs.

Mycobacterium tuberculosis is the focus of several investigations for design of newer drugs, as tuberculosis remains a major epidemic despite the availability of several drugs and a vaccine. Mycobacteria owe many of their unique qualities to mycolic acids, which are known to be important for their growth, survival, and pathogenicity. Mycolic acid biosynthesis has therefore been the focus of a number of biochemical and genetic studies. It also turns out to be the pathway inhibited by front-line anti-tubercular drugs such as isoniazid and ethionamide. Recent years have seen the emergence of systems-based methodologies that can be used to study microbial metabolism. Here, we seek to apply insights from flux balance analyses of the mycolic acid pathway (MAP) for the identification of anti-tubercular drug targets. We present a comprehensive model of mycolic acid synthesis in the pathogen M. tuberculosis involving 197 metabolites participating in 219 reactions catalysed by 28 proteins. Flux balance analysis (FBA) has been performed on the MAP model, which has provided insights into the metabolic capabilities of the pathway. In silico systematic gene deletions and inhibition of InhA by isoniazid, studied here, provide clues about proteins essential for the pathway and hence lead to a rational identification of possible drug targets. Feasibility studies using sequence analysis of the M. tuberculosis H37Rv and human proteomes indicate that, apart from the known InhA, potential targets for anti-tubercular drug design are AccD3, Fas, FabH, Pks13, DesA1/2, and DesA3. Proteins identified as essential by FBA correlate well with those previously identified experimentally through transposon site hybridisation mutagenesis. This study demonstrates the application of FBA for rational identification of potential anti-tubercular drug targets, which can indeed be a general strategy in drug design. The targets, chosen based on the critical points in the pathway, form a ready shortlist for experimental testing.

Algorithms↗

PubMed2003

Proteomic analysis of the cell-surface membrane in chronic lymphocytic leukemia: identification of two novel proteins, BCNP1 and MIG2B.

B-cell-specific plasma-membrane proteins are potential targets for either small molecule or antibody-based therapies. We have sought to annotate proteins expressed at the cell surface membrane in patients with chronic lymphocytic leukemia (CLL) using plasma-membrane-based proteomic analysis to identify previously uncharacterized and potentially B-cell-specific proteins. Proteins from plasma-membrane fractions were separated on one-dimensional gels and trypsinized fractions subjected to high-throughput MALDI-TOF mass spectrometry. Using this method, many known B-cell surface antigens were detected, but also known proteins not previously described in this disease or in this cellular compartment, including cell surface receptors, membrane-associated enzymes and secreted proteins, and completely unknown proteins. To validate the method, we show that BLK, a B-cell-specific kinase, is located in the CLL-plasma-membrane fraction. We also describe two novel proteins (MIG2B and B-cell novel protein #1, BCNP1), which are expressed preferentially in B cells. MIG2B is in a highly conserved and defined gene family containing two plasma-membrane-binding ezrin/radixin/moesin domains and a pleckstrin homology domain; the Caenorhabditis elegans homolog (UNC-112) is a membrane-associated protein that colocalizes with integrin at cell-matrix adhesion complexes. BCNP1 is a completely unknown protein with three predicted transmembrane domains, with three alternatively spliced final exons. Proteomic analysis may thus define new potential therapeutic targets.

Apoptosis Regulatory Proteins↗

PubMed2006

Phorboxazole analogues induce association of cdk4 with extranuclear cytokeratin intermediate filaments.

The cellular localization profile and molecular association of the phorboxazoles were examined with a streamlined target elucidation system using synthetic fluorescent probes. Cellular image analyses identified the binding of phorboxazole analogues to cytosolic components. Proteomic analysis directed at fluorescently labeled cytosolic fractions indicated that the primary targets observed microscopically were cytokeratins, as verified by determination of low nanomolar binding to cloned and expressed proteins. Phorboxazole probes localized the essential cell cycle promoter cdk4 upon cytokeratin networks.

Cell Cycle↗