基于timsTOF Pro2的非标记单细胞蛋白质组学技术优化

Optimization of the Routine Approach for Label-Free Single-Cell Proteomics Using timsTOF Pro2 MS

  • 摘要: 单细胞蛋白质组学(SCP)以解析组织微环境中细胞间的蛋白质异质性为核心目标,其依赖于高灵敏度质谱平台,如timsTOF Pro2质谱仪。本研究通过系统优化timsTOF Pro2质谱的操作流程,展示在该平台获得可靠数据的可行性,为类似设备的使用提供优化方案。以HeLa细胞为模型,采用CellenONE进行单细胞分选,通过系统优化裂解缓冲液组成、酶解时间等前处理条件,并结合纳升液相色谱(nLC)的柱型、洗脱梯度、流速与温度参数,以及timsTOF Pro2质谱在数据非依赖采集(DIA)模式下的m/z隔离窗口和斜坡时间,建立了一套低成本、高效的单细胞蛋白质组分析流程。优化后的方法使用含十二烷基麦芽苷(DDM)的碳酸氢铵缓冲体系及2 h胰酶酶解,显著提升了蛋白质提取效率与重复性,样本间蛋白重叠率达78%~82%,定量相关系数超过0.88;采用6 cm nLC柱、15 min短梯度、200 nL/min流速及45 ℃柱温,质谱参数中斜坡时间设为125 ms,最终在单个HeLa细胞中平均鉴定到2 459种蛋白质。结果表明,通过系统优化timsTOF Pro2平台的参数,可在单细胞水平实现深度蛋白质组鉴定。本研究为高性能LC-MS平台的使用提供了一套可借鉴的优化方案,为相关基础研究提供了方法学参考。

     

    Abstract: Single-cell proteomics (SCP) aims to resolve protein heterogeneity among cells within tissue microenvironments. Single-cell proteomics analysis inherently relies on high-sensitivity mass spectrometry platforms. In this study, a series of optimizations for SCP analysis in a routine approach based on timsTOF Pro2 MS was reported. HeLa cells were selected as testing materials and processed to single cells through CellenONE. Single HeLa cells were treated under different experimental conditions, such as lysis buffer, cell disruption, and digestion period, to seek an optimized protocol with enhanced efficiency of protein extraction. For optimizing LC conditions, the samples with 5 ng were loaded onto the LC, and chromatographic parameters such as LC column type, elution gradient, flow rate, and column temperature were assessed. Mass spectrometer of timsTOF Pro2 was used under data-independent acquisition (DIA) mode, and the acquisition parameters were focused on m/z isolation window and ramp time. For protein extraction, an ammonium bicarbonate buffer system combined with n-Dodecyl-β-D-maltoside (DDM) and two-hour enzymatic digestion enabled an increase of the identified proteins. With the extraction system, analytical reproducibility reached a stable status, the overlap rate of inter-samples at 78%-82% and the correlation coefficients of protein quantification exceeding 0.88. In chromatography to separate 5 ng peptides, a 6 cm column was employed under a 15 min short gradient with a flow rate of 200 nL/min at temperature of 45 ℃. During the refinement of mass spectrometry parameters, the m/z isolation window was set at 125 ms ramp time. The optimized method achieved remarkable performance in protein identification at single-cell level, with an average of 2 459 proteins/HeLa cell. Through systematic optimization of the parameters of the timsTOF Pro2 platform, deep proteome identification can be achieved at the single-cell level. This study provides a set of optimizable solutions for laboratories equipped with similar high-performance LC-MS platforms, and preliminarily validates its applicability in multiple cell lines, offering methodological references for related basic research.

     

/

返回文章
返回