National Institute for Bioprocessing Research and Training, Foster Avenue, Mount Merrion, Blackrock, Co. Dublin, A94 X099, Ireland.
School of Chemical and Bioprocess Engineering, University College Dublin (UCD), Belfield, Dublin 4, D04 V1W8, Ireland.
Glycobiology. 2024 Mar 19;34(1). doi: 10.1093/glycob/cwad074.
Adeno-associated virus (AAV) vector has become the leading platform for gene delivery. Each serotype exhibits a different tissue tropism, immunogenicity, and in vivo transduction performance. Therefore, selecting the most suitable AAV serotype is critical for efficient gene delivery to target cells or tissues. Genome divergence among different serotypes is due mainly to the hypervariable regions of the AAV capsid proteins. However, the heterogeneity of capsid glycosylation is largely unexplored. In the present study, the N-glycosylation profiles of capsid proteins of AAV serotypes 1 to 9 have been systemically characterized and compared using a previously developed high-throughput and high-sensitivity N-glycan profiling platform. The results showed that all 9 investigated AAV serotypes were glycosylated, with comparable profiles. The most conspicuous feature was the high abundance mannosylated N-glycans, including FM3, M5, M6, M7, M8, and M9, that dominated the chromatograms within a range of 74 to 83%. Another feature was the relatively lower abundance of fucosylated and sialylated N-glycan structures, in the range of 23%-40% and 10%-17%, respectively. However, the exact N-glycan composition differed. These differences may be utilized to identify potential structural relationships between the 9 AAV serotypes. The current research lays the foundation for gaining better understanding of the importance of N-glycans on the AAV capsid surface that may play a significant role in tissue tropism, interaction with cell surface receptors, cellular uptake, and intracellular processing.
腺相关病毒 (AAV) 载体已成为基因传递的主要平台。每种血清型都表现出不同的组织趋向性、免疫原性和体内转导性能。因此，选择最合适的 AAV 血清型对于将基因有效地递送到靶细胞或组织至关重要。不同血清型之间的基因组差异主要归因于 AAV 衣壳蛋白的高变区。然而，衣壳糖基化的异质性在很大程度上尚未得到探索。在本研究中，使用先前开发的高通量和高灵敏度 N-糖谱分析平台，系统地分析和比较了 AAV 血清型 1 至 9 的衣壳蛋白的 N-糖基化谱。结果表明，所有 9 种研究的 AAV 血清型均被糖基化，具有可比的谱。最显著的特征是富含甘露糖的 N-聚糖的高丰度，包括 FM3、M5、M6、M7、M8 和 M9，它们在 74 到 83%的范围内主导色谱图。另一个特征是低丰度的岩藻糖基化和唾液酸化 N-聚糖结构，分别在 23%-40%和 10%-17%的范围内。然而，确切的 N-糖组成不同。这些差异可能被用来识别 9 种 AAV 血清型之间潜在的结构关系。目前的研究为更好地理解 N-聚糖在 AAV 衣壳表面的重要性奠定了基础，这可能在组织趋向性、与细胞表面受体的相互作用、细胞摄取和细胞内加工中发挥重要作用。
