Elsevier

Metabolic Engineering

Volume 21, January 2014, Pages 91-102
Metabolic Engineering

CHO cell engineering to prevent polypeptide aggregation and improve therapeutic protein secretion

https://doi.org/10.1016/j.ymben.2012.12.003Get rights and content
Under a Creative Commons license
open access

Abstract

The ability to efficiently produce recombinant proteins in a secreted form is highly desirable and cultured mammalian cells such as CHO cells have become the preferred host as they secrete proteins with human-like post-translational modifications. However, attempts to express high levels of particular proteins in CHO cells may consistently result in low yields, even for non-engineered proteins such as immunoglobulins. In this study, we identified the responsible faulty step at the stage of translational arrest, translocation and early processing for such a “difficult-to-express” immunoglobulin, resulting in improper cleavage of the light chain and its precipitation in an insoluble cellular fraction unable to contribute to immunoglobulin assembly. We further show that proper processing and secretion were restored by over-expressing human signal receptor protein SRP14 and other components of the secretion pathway. This allowed the expression of the difficult-to-express protein to high yields, and it also increased the production of an easy-to-express protein. Our results demonstrate that components of the secretory and processing pathways can be limiting, and that engineering of the secretory pathway may be used to improve the secretion efficiency of therapeutic proteins from CHO cells.

Highlights

► “Difficult-to-express” proteins consistently yield low expression from mammalian cells. ► Low protein secretion can stem from faulty cleavage and precipitation in degradation organelles. ► Expression of translational arrest and secretion pathway components restores proper secretion. ► Secretion pathway engineering also increases expression of an easy-to-express immunoglobulin. ► Metabolic engineering thus resolves CHO cell protein processing and secretion bottlenecks.

Keywords

CHO cells
Metabolic engineering
Protein secretion
Therapeutic proteins
Immunoglobulins

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