protein extraction from human tear using schirmer strip

使用 LC-MS 进行泪液蛋白质组学的非侵入性生物标志物发现

Tear proteomics has received attention to explore potential biomarkers for ocular diseases and conditions1,2,3,4,5,6, to access the pathogenesis of the ocular and systemic condition, as well as to exploit the advantage of non-invasive tear sample collection using Schirmer strips. The technological advancement of next-generation mass spectrometry has enabled protein quantification in microliter-scale tears with accuracy and precision not possible in the past. Sample preparation methods are not yet standardized. A robust and standardized sample preparation workflow is essential for the success of clinical application in tear protein biomarker research. The suspension trapping (S-Trap) sample preparation workflow was recently reported as an effective and sensitive sample preparation method for broad downstream proteomic analysis7,8. Yet, this strategy has not been well-reported in the analysis of human tear proteome, outperformed filter-aided sample preparation (FASP) and in-solution digestion in terms of enzymatic digestion efficiency and the greater number of protein identification by mass spectrometric analysis9. The S-Trap-based approach was demonstrated in the preparation of retinal tissue 10, formalin-fixed, paraffin-embedded (FFPE) tissue11, cells12, microorganism13, and liquid biopsies14,15.
This protocol describes an integrated quantitative workflow from clinical samples to enzymatically digested protein for the discovery of a non-invasive tear protein biomarker panel with a rapid, reproducible, and robust technical strategy. Briefly, tear fluid was collected using a standard Schirmer strip and immediately dried with an ophthalmic frame heater to prevent protein autolysis at room temperature. Embedded total proteins were extracted using 5% sodium dodecyl sulfate (SDS) lysis buffer according to the manufacturer&#39;s suggestion, followed by protein assay measurement. The extracted lysate then underwent standard reduction with dithiothreitol (DTT) and alkylation with iodoacetamide (IAA).
After acidification with phosphoric acid, suspension trapping column protein precipitation buffer containing 90% methanol and 100 mM triethylammonium bicarbonate (TEAB) was added to aggregate proteins. The sample was then transferred into a new suspension trapping micro column. Enzymatic digestion with done with sequencing grade trypsin at a 1:25 ratio (w/w, trypsin: protein) at 47 &#176;C for 1 h. The resulting peptides were then eluted via centrifugation, sequentially with 50 mM TEAB, 0.2% aqueous formic acid (FA), and 50% acetonitrile (ACN) containing 0.2% FA. The eluted peptides were vacuum-dried and reconstituted in 0.1 % FA. The peptide concentration was measured and adjusted to 0.5 &#181;g/&#181;L for mass spectrometric analysis.

作者聚焦：使用蛋白质组学研究的标准化方案推进泪液分析 

液相色谱-串联质谱法制备泪液蛋白质组学的蛋白质悬浮捕获样品

Watch this Scientific Journal Video about Protein Extraction from Human Tear Using Schirmer Strip at JoVE.com

Protein Extraction from Human Tear Using Schirmer Strip  

使用 Schirmer 试纸从人体泪液中提取蛋白质

首先切割并丢弃 Schirmer 条带的前端，其中包含超过零毫米标记的干人眼泪。然后将条带切成一毫米的间隔，并将碎片放入 1.5 毫升的微型离心管中。接下来，向微量离心管中加入 100 微升裂解缓冲液。在室温下以 1000 RPM 在热混合器中涡旋一小时。短暂离心后，将上清液转移到新的1.5毫升微量离心管中。使用干净的镊子，将条带移入 200 微升移液器吸头中。将吸头放回同一个微量离心管中，然后离心以获得最大的样品回收率。使用二辛可宁酸或兼容的蛋白质测定法测量蛋白质浓度。

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Research

JoVE Journal

Medicine

Protein Extraction from Human Tear Using Schirmer Strip

465 次观看. 首先切割并丢弃 Schirmer 条带的前端，其中包含超过零毫米标记的干人眼泪。然后将条带切成一毫米的间隔，并将碎片放入 1.5 毫升的微型离心管中。接下来，向微量离心管中加入 100 微升裂解缓冲液。在室温下以 1000 RPM 在热混合器中涡旋一小时。短暂离心后，将上清液转移到新的1.5毫升微量离心管中。使用干净的镊子，将条带移入 200 微升移液器吸头中。将吸头放?...

视频: Protein Extraction from Human Tear Using Schirmer Strip  

A Protein Suspension-Trapping Sample Preparation for Tear Proteomics by Liquid Chromatography-Tandem Mass Spectrometry

Tear fluid is one of the easily accessible biofluids that can be collected non-invasively. Tear proteomics has the potential to discover biomarkers for several ocular diseases and conditions. The suspension trapping column has been reported to be an efficient and user-friendly sample preparation workflow for the broad application of downstream proteomic analysis. Yet, this strategy has not been well-studied in the analysis of human tear proteome. The present protocol describes an integrated workflow from clinical human tear samples to purified peptides for non-invasive tear protein biomarker research using mass spectrometry, which provides insights into disease biomarkers and monitoring when combined with bioinformatics analysis. A protein suspension trapping sample preparation was applied and demonstrated the discovery of tear proteome with fast, reproducible, and user-friendly procedures, as a universal, optimized sample preparation for human tear fluid analysis. In particular, the suspension trapping procedure outperformed in-solution sample preparation in terms of peptide recovery, protein identification, and shorter sample preparation time.

This protocol describes a method for collecting tear samples using Schirmer strips and an integrated quantitative workflow for discovering non-invasive tear protein biomarkers. The suspension trapping sample preparation workflow enables fast and robust tear sample preparation and mass spectrometric analysis, resulting in higher peptide recovery yields and protein identification than standard in-solution procedures.

Tear fluid is one of the easily accessible biofluids that can be collected non-invasively. Tear proteomics has the potential to discover biomarkers for ...