Institute of Applied Biotechnology, University of Applied Sciences Biberach, Biberach an der Riss, Germany.
USP Development, Novartis AG, Kundl, Austria.
Appl Microbiol Biotechnol. 2022 Sep;106(18):6157-6167. doi: 10.1007/s00253-022-12123-6. Epub 2022 Aug 30.
The production of biopharmaceuticals relies on robust cell systems that can produce recombinant proteins at high levels and grow and survive in the stressful bioprocess environment. Chinese hamster ovary cells (CHO) as the main production hosts offer a variety of advantages including robust growth and survival in a bioprocess environment. Cell surface proteins are of special interest for the understanding of how CHO cells react to their environment while maintaining growth and survival phenotypes, since they enable cellular reactions to external stimuli and potentially initiate signaling pathways. To provide deeper insight into functions of this special cell surface sub-proteome, pathway enrichment analysis of the determined CHO surfaceome was conducted. Enrichment of growth/ survival-pathways such as the phosphoinositide-3-kinase (PI3K)-protein kinase B (AKT), mitogen-activated protein kinase (MAPK), Janus kinase/signal transducers and activators of transcription (JAK-STAT), and RAP1 pathways were observed, offering novel insights into how cell surface receptors and ligand-mediated signaling enable the cells to grow and survive in a bioprocess environment. When supplementing surfaceome data with RNA expression data, several growth/survival receptors were shown to be co-expressed with their respective ligands and thus suggesting self-induction mechanisms, while other receptors or ligands were not detectable. As data about the presence of surface receptors and their associated expressed ligands may serve as base for future studies, further pathway characterization will enable the implementation of optimization strategies to further enhance cellular growth and survival behavior. KEY POINTS: • PI3K/AKT, MAPK, JAK-STAT, and RAP1 pathway receptors are enriched on the CHO cell surface and downstream pathways present on mRNA level. • Detected pathways indicate strong CHO survival and growth phenotypes. • Potential self-induction of surface receptors and respective ligands.
生物制药的生产依赖于能够高水平生产重组蛋白并在生物工艺环境中生长和存活的强大细胞系统。中国仓鼠卵巢细胞（CHO）作为主要生产宿主，具有多种优势，包括在生物工艺环境中强大的生长和存活能力。细胞表面蛋白对于了解 CHO 细胞如何在维持生长和存活表型的同时对其环境做出反应特别感兴趣，因为它们使细胞能够对外界刺激做出反应，并可能启动信号通路。为了更深入地了解这个特殊的细胞表面亚蛋白组的功能，对确定的 CHO 表面组进行了途径富集分析。观察到了生长/存活途径的富集，如磷脂酰肌醇-3-激酶（PI3K）-蛋白激酶 B（AKT）、丝裂原活化蛋白激酶（MAPK）、Janus 激酶/信号转导和转录激活因子（JAK-STAT）和 RAP1 途径，为细胞表面受体和配体介导的信号如何使细胞在生物工艺环境中生长和存活提供了新的见解。当将表面组数据与 RNA 表达数据补充时，发现几个生长/存活受体与各自的配体共同表达，因此暗示了自我诱导机制，而其他受体或配体则无法检测到。由于关于表面受体存在及其相关表达配体的数据可能作为未来研究的基础，因此进一步的途径特征描述将能够实施优化策略，以进一步增强细胞生长和存活行为。关键点：
PI3K/AKT、MAPK、JAK-STAT 和 RAP1 途径受体在 CHO 细胞膜上富集，并且在 mRNA 水平上存在下游途径。
检测到的途径表明 CHO 具有强大的存活和生长表型。
表面受体和相应配体的潜在自我诱导。
