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

Area of Science:

• Biotechnology
• Cell Biology
• Protein Engineering

Background:

• CHO cells are preferred for recombinant protein production due to human-like post-translational modifications.
• Low yields of specific proteins, like immunoglobulins, can occur even in CHO cells.
• Identifying bottlenecks in protein secretion is crucial for improving production.

Purpose of the Study:

• To identify the limiting step in the secretion of "difficult-to-express" immunoglobulins in CHO cells.
• To investigate if enhancing the secretion pathway can improve protein yields.
• To demonstrate the potential of engineering the secretory pathway for therapeutic protein production.

Main Methods:

• Analysis of translational arrest, translocation, and early processing stages.
• Investigating immunoglobulin light chain cleavage and precipitation.
• Over-expression of human signal receptor protein SRP14 and other secretion pathway components.

Main Results:

• A faulty step in translational arrest, translocation, and early processing was identified for difficult-to-express immunoglobulins.
• Improper light chain cleavage and precipitation were observed.
• Over-expressing SRP14 and other secretion components restored proper processing and secretion.
• High yields of the difficult-to-express protein were achieved, along with increased production of an easy-to-express protein.

Conclusions:

• Components of the secretory and processing pathways can be rate-limiting for recombinant protein production.
• Engineering the secretory pathway is a viable strategy to enhance the secretion efficiency of therapeutic proteins from CHO cells.
• This approach can improve yields for both difficult-to-express and easy-to-express proteins.