Single Cell Peptidomics: Approach for Peptide Identification by N-Terminal Peptide Derivatization

Recent advances in mass spectrometry analysis of neuropeptides

Due to their involvement in numerous biochemical pathways, neuropeptides have been the focus of many recent research studies. Unfortunately, classic analytical methods, such as western blots and enzyme-linked immunosorbent assays, are extremely limited in terms of global investigations, leading researchers to search for more advanced techniques capable of probing the entire neuropeptidome of an organism. With recent technological advances, mass spectrometry (MS) has provided methodology to gain global knowledge of a neuropeptidome on a spatial, temporal, and quantitative level. This review will cover key considerations for the analysis of neuropeptides by MS, including sample preparation strategies, instrumental advances for identification, structural characterization, and imaging; insightful functional studies; and newly developed absolute and relative quantitation strategies. While many discoveries have been made with MS, the methodology is still in its infancy. Many of the current challenges and areas that need development will also be highlighted in this review.

Identifying Receptors for Neuropeptides and Peptide Hormones: Challenges and Recent Progress

Intercellular signaling events mediated by neuropeptides and peptide hormones represent important targets for both basic science and drug discovery. For many bioactive peptides, the protein receptors that transmit information across the receiving cell membrane are not known, severely limiting these signaling pathways as potential therapeutic targets. Identifying the receptor(s) for a given peptide of interest is complicated by several factors. Most notably, cell-cell signaling peptides are generated through dynamic biosynthetic pathways, can act on many different families of receptor proteins, and can participate in complex ligand-receptor interactions that extend beyond a simple one-to-one archetype. Here, we discuss recent methodological advances to identify signaling partners for bioactive peptides. Recent efforts have centered on methods to identify candidate receptors via transcript expression, methods to match peptide-receptor pairs through high throughput screening, and methods to capture direct ligand-receptor interactions using chemical probes. Future applications of the receptor identification approaches discussed here, as well as technical advancements to address their limitations, promise to lead to a greater understanding of how cells communicate to deliver complex physiologies. Importantly, such advancements will likely provide novel targets for the treatment of human diseases within the central nervous and endocrine systems.

[Preliminary Study on the Biological Markers for I-IIb Stage Non-small Cell Lung Cancer Based on a Serum-peptidomics]

背景与目的

非小细胞肺癌是发病率最高的一种肺恶性肿瘤，早发现、早诊断、早治疗是其治疗原则，因其发病隐匿，缺乏早期筛查的特异性标志物，多数患者就诊时已处于晚期阶段，导致其5年生存率较低，预后不理想。探索一种敏感的生物学标志物，是目前肺癌诊疗的重点。本文基于差异多肽组学技术，旨在筛选Ⅰ期-Ⅱb期非小细胞肺癌的血清生物标志物。

方法

利用纳升超高效液相色谱联合四级杆轨道阱质谱技术，比较和筛选正常健康人群、肺部良性病变患者、非小细胞肺癌患者血清中的差异多肽片段，通过对目标肽段的鉴别和定量分析，探寻非小细胞肺癌早期诊断的肿瘤生物标志物。

结果

通过与人类蛋白质组数据库进行比对，共鉴定到545个多肽，分别来自118个蛋白。将各组样本中肽段的谱图数进行比较，共筛选出201个差异多肽，经定量分析发现峰面积的变异系数（coefficient of variation, CV）≤30%的目标肽段共计7个，其中在各组间呈趋势变化的有2条肽段，分别是肺癌组中表达下调的肽段QGAKIPKPEASFSPR和肺癌组中表达上调的肽段CDDYRLC，它们分别来自于中间α球蛋白抑制因子H4蛋白（ITIH4）和基质γ-羧基谷氨酸蛋白（MGP）。

结论

将血清多肽组学用于筛选肿瘤标志物的研究，可为非小细胞肺癌的早期诊断提供新线索，其中ITIH4与MGP蛋白水解的特异性肽段是潜在早期非小细胞肺癌患者的血清标志物。