Denti Vanna, Monza Nicole, Bindi Greta, Porto Natalia Shelly, L'Imperio Vincenzo, Pagni Fabio, Piga Isabella, Smith Andrew
Proteomics and Metabolomics Unit, Department of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy.
Pathology Unit, Department of Medicine and Surgery, Fondazione IRCCS San Gerardo dei Tintori, University of Milano-Bicocca, 20900 Monza, Italy.
Int J Mol Sci. 2024 Dec 21;25(24):13678. doi: 10.3390/ijms252413678.
Matrix Assisted Laser Desorption/Ionisation-Mass Spectrometry Imaging (MALDI-MSI) is a well-established spatial omic technique which enables the untargeted mapping of various classes of biomolecules, including tryptic peptides, directly on tissue. This method relies on the use of matrices for the ionisation and volatilisation of analytes, and α-Cyano-4-hydroxycinnamic acid (CHCA) represents the most widespread matrix for tryptic peptides analysis. However, CHCA also presents certain limitations that foster the quest for novel matrix compounds. 6-aza-2-thiothymine (ATT), traditionally used in MALDI mass spectrometry (MS) for oligonucleotides, small molecules and oxidised phospholipids, has not been thoroughly investigated as a potential matrix for tryptic peptide analysis in MALDI-MS or MALDI-MSI. Therefore, this study addresses this gap by evaluating the capability of ATT to ionise tryptic peptides from Bovine Serum Albumin (BSA) and map in situ-digested peptides from formalin-fixed paraffin-embedded (FFPE) tissue sections in these respective applications. Comparative analysis with CHCA demonstrated the complementary strengths of these matrices for detecting tryptic peptides, establishing ATT as a feasible alternative to CHCA in the MALDI-MSI field and paving the way for future advancements in spatial proteomics.
基质辅助激光解吸/电离质谱成像（MALDI-MSI）是一种成熟的空间组学技术，能够在组织上直接对包括胰蛋白酶解肽段在内的各类生物分子进行非靶向图谱分析。该方法依赖于使用基质来实现分析物的电离和挥发，α-氰基-4-羟基肉桂酸（CHCA）是用于胰蛋白酶解肽段分析的最常用基质。然而，CHCA也存在一定局限性，这促使人们寻找新型基质化合物。6-氮杂-2-硫胸腺嘧啶（ATT）传统上用于MALDI质谱（MS）分析寡核苷酸、小分子和氧化磷脂，但尚未作为MALDI-MS或MALDI-MSI中胰蛋白酶解肽段分析的潜在基质进行深入研究。因此，本研究通过评估ATT在这些应用中电离牛血清白蛋白（BSA）中的胰蛋白酶解肽段以及对福尔马林固定石蜡包埋（FFPE）组织切片中原位消化肽段进行图谱分析的能力，填补了这一空白。与CHCA的对比分析证明了这些基质在检测胰蛋白酶解肽段方面的互补优势，确立了ATT作为MALDI-MSI领域中CHCA的可行替代物，并为空间蛋白质组学的未来发展铺平了道路。
