Project description:Plasma is a highly valuable resource for biomarker research since it is easy obtainable and contains a high amount of information on patient health status. Although advancements in the field of proteomics enabled analysis of the plasma proteome, identification of low abundant proteins remains challenging due to high complexity and large dynamic range. In order to reduce the dynamic range of protein concentrations, a tandem depletion technique consisting of ammonium sulfate precipitation and Protein A affinity chromatography was developed. Using this method, 50 % of albumin, together with other high abundant proteins such as alpha-1-antitrypin, was depleted from the plasma sample at 20 % to 40 % ammonium sulfate saturation levels. In combination with immunoglobulin removal using a Protein A column, this technique delivered up to 40 new low- to medium abundance protein identifications when performing a shotgun mass spectrometry analysis. Compared to non-depleted plasma, 270 additional protein spots were observed during 2D-PAGE analysis. These results illustrate that this tandem depletion method is equivalent to commercial kits which are based on immune-affinity chromatography. Moreover, this method using protein A immunoglobulin depletion was shown to be highly reproducible and a minimal amount of non-target proteins was depleted. The combination of ammonium sulfate precipitation and Protein A affinity chromatography offers a low cost, efficient, straightforward and reproducible alternative to commercial kits, with proteins remaining in native conformation, allowing protein activity and protein interaction studies.
Project description:We assess the mRNA-enrichment performance of a custom-made non-mRNA depletion protocol in comparison to a commercially available mRNA-enrichment kit (Ribo-off, Vazyme). Whereas most available kits focus only on removal of rRNA, our method also targets the transfer-messenger RNA (tmRNA). tmRNA was shown to consume up to 25% of the reads in RNA-sequencing data of Pseudomonas aeruginosa. Our established depletion technique is based on the targeting of overly abundant RNA species (16S and23S rRNA, tmRNA) in total RNA preparations of Pseudomonas aeruginosa PA14 by hybridization with organism-specific DNA probes and subsequent degradation by RNase H treatment. While introducing no systematic bias into the gene expression profile we were able to increase the mRNA read share of the total reads in the samples treated with our mRNA-enrichment protocol to 93% - 99%. Therefore, our custom-made depletion technique outcompeted the commercially available reference kit (72% mRNA share) and represents a cost-efficient mRNA-enrichment method for high-throughput next-generation sequencing.
Project description:Serum miRNAs are considered useful as non-invasive biomarkers for various diseases, but the optimal method for extracting RNA from serum is currently unknown. In this study, several RNA extraction kits were used to determine which kit is the optimal method. RNA was extracted from the serum of 8-week-old C57BL/6NJcl male mice according to the protocol of each RNA extraction kit. The yield of extracted RNA samples was calculated and electrophoretic patterns were evaluated by Agilent bioanalyzer. Expression patterns of the extracted RNA samples were confirmed by Agilent mouse miRNA microarray. The results showed significant differences in RNA yields in the miRNeasy serum/plasma advanced kit, and mirVana™ PARIS™ RNA and Native Protein Purification Kit compared to almost all other samples. Furthermore, two peaks were identified in the miRNeasy serum/plasma advanced kit using small RNA kit of Agilent bioanalyzer, one at 20-40 nucleotides (nt) and the other around 40-100 nt whereas the other reagents had a single peak. In addition, a high correlation was observed between the two RNA extraction kits in microarray. These results suggest that the above two kits are suitable for miRNA extraction from mouse serum.
Project description:Objectives: Hashimoto’s thyroiditis (HT) is one of the most common autoimmune disorders; however, its underlying pathological mechanisms remain unclear. Although aberrant glycosylation has been implicated in the N-glycome of immunoglobulin G (IgG), changes in serum proteins have not been comprehensively characterized. This study aimed to investigate the glycosylation profile of serum samples of HT patients that were depleted of highly abundant proteins by and propose the potential functions of glycoproteins for the further study of pathological mechanisms of HT . Methods: A lectin microarray containing 70 lectins was used to detect and analyze glycosylation of serum proteins using serum samples (N=27 HT; N=26 healthy control [HC]) depleted of abundant proteins. Significant differences in glycosylation status between HT patients and the HC group were verified by lectin blot analysis. A lectin-based pull-down assay combined with mass spectrometry was used to investigate potential glycoproteins combined with differentially present lectins, and an enzyme-linked immunosorbent assay (ELISA) was used to identify the expression of targeted glycoproteins in 131 patients with papillary thyroid carcinoma (PTC), 131 patients with benign thyroid nodules (BTN) patients, 130 patients with HT, and 128 HCs. Results: Compared with the HC group, the majority of the lectin binding signals in HT group were weakened, while the Vicia villosa agglutinin (VVA) binding signal was increased. The difference in VVA binding signals verified by lectin blotting was consistent with the results of the lectin microarray. A total of 113 potential VVA-binding glycoproteins were identified by mass spectrometry and classified by gene ontology (GO) and kyoto encyclopedia of genes and genomes (KEGG) analyses . Using ELISA, we confirmed that lactoferrin (LTF) and mannan-binding lectin-associated serine protease 1 (MASP-1) levels were elevated in the serum of patients with HT and PTC. Conclusions: Following depletion of abundant proteins, remaining serum proteins in HT patients exhibited lower glycosylation levels than those observed in HCs. An increased level of potential VVA-binding glycoproteins may play an important role in HT development. LTF and MASP-1 expression was significantly higher in the serum of HT and PTC patients, suggesting key roles played by glycosylation in pathological mechanisms underlying HT and PTC.
Project description:LC-MS/MS data of digested human and rabbit serum samples. Experiments were conducted using Dionex UltiMate 3000 (Thermo Fisher Scientific, USA) LC system connected to a Q Exactive HF-X mass spectrometer (Thermo Fisher Scientific, Waltham, MA). Peptide spectrum matching of MS/MS spectra of each file was searched against the UniProt reviewed Human protein database (TaxID: UP000005640) using the Sequest algorithm within Proteome Discoverer v 2.4 software (Thermo Fisher Scientific, San Jose, CA).
Project description:Rabbits have been widely used for studying ocular physiology and pathology due to their relatively large eye size and similar structures with human eyes. Various rabbit ocular disease models, such as dry eye, age-related macular degeneration, and glaucoma, have been established. Despite the growing application of proteomics in vision research using rabbit ocular models, there is no spectral assay library for rabbit eye proteome publicly available. Here, we generated spectral assay libraries for rabbit eye compartments, including conjunctiva, cornea, iris, retina, sclera, vitreous humor, and tears using fractionated samples and ion mobility separation enabling deep proteome coverage. The rabbit eye spectral assay library includes 9,830 protein groups and 113,593 peptides. We present the data as a freely available community resource for proteomic studies in the vision field.
Project description:5' tRNA halves are abundantly present in small RNA libraries prepared from serum samples, thereby limiting the detection of other small RNA species. In this study, we developed and compared two protocols for the selective depletion of 5' tRNA halves in RNA isolated from murine serum samples. To evaluate the efficacy of both protocols on small RNA sequencing, we performed the two 5' tRNA halves depletion protocols on total RNA isolated from a serum pool collected from healthy mice. Each RNA sample was divided into three and the resulting fractions were either depleted using beads or RNase H, or used as a control. The experiment was performed in triplicate. Upon depletion, libraries were prepared using TruSeq Small RNA Library Preparation kit. For both protocols, very high depletion efficiencies were observed, with more than 99% of the targeted tRNA-types being depleted. This resulted in a more than 6-fold increase in mapped miRNA reads and 60% more detected mature miRNAs when performing small RNA sequencing on murine serum samples. Importantly, we observed no considerable effects on the relative expression values of miRNAs.
Project description:present study, we evaluated four small molecule affinity-based probes based on agarose-immobilized benzamidine (ABA), O-Phospho-L-Tyrosine (pTYR), 8-Amino-hexyl-cAMP (cAMP), or 8-Amino-hexyl-ATP (ATP) for their ability to remove high-abundant proteins such as serum albumin from plasma samples thereby enabling the detection of medium-to-low abundant proteins in plasma samples by mass spectrometry-based proteomics. We compared their performance with the commonly used immunodepletion method, the Multi Affinity Removal System Human 14 (MARS14) targeting the top 14 most abundant plasma proteins and also the ProteoMiner protein equalization method by label-free quantitative LC-MSMS analysis. The affinity-based probes demonstrated high reproducibility for low abundant plasma proteins, down to picomol per ml levels, compared to the MARS14 and the Proteominer methods, and also demonstrated a superior removal of the majority of the high abundant plasma proteins. The ABA-based affinity probe and the Proteominer protein equalization method performed superior compared to all other methods in terms of the number of analyzed proteins. All the tested methods were highly reproducible for both high-abundant plasma proteins and low abundant proteins as measured by correlation analysis of six replicate experiments. In conclusion, our results demonstrated that small-molecule based affinity-based probes are excellent alternatives to the commonly used immune-depletion methods for proteomic biomarker discovery studies in plasma.
Project description:LC-MS/MS raw data acquired using commercially available abundant protein depletion columns using serum of normal human and non-injured rat acquired on Orbitrap Fusion Lumos Mass Spectrometer.