Engineers in the US are one step closer to mass-producing therapeutic proteins needed by today's pharmaceutical industry.
Reporting in last week's online edition of the Proceedings of the National Academy Of Sciences, the researchers claim to have achieved a major milestone in their efforts to effectively produce human therapeutics using a yeast-based protein expression system.
The research is the result of a collaborative effort between researchers in Dartmouth, New Haven and a bioengineering startup called GlycoFi. Founded by two Dartmouth engineering professors, GlycoFi is advancing technological solutions for the mass-production of fully-humanised proteins.
Protein-based biological drugs must be manufactured by living cells, which are genetically engineered to produce (or express) proteins that mimic the structures synthesised by humans. Current production of these therapeutic proteins is being pushed beyond capacity by exponential growth in the biopharmaceutical industry. GlycoFi's business is to engineer fungal expression systems that produce therapeutic proteins with human-like structures at an industrial scale.
"Production capacity has led to a bottleneck within the biopharmaceutical pipeline," said Charles Hutchinson, co-founder and CEO of GlycoFi, as well as dean emeritus of Dartmouth's Thayer school of engineering. "The result is that some approved therapeutic protein drugs cannot be produced in adequate amounts, and still others are not making it into commercialisation due to the cost and inefficiencies of producing them. It is our hope that this push to producing homogeneous, human-like glycoproteins in yeast will eliminate the production capacity bottleneck, and allow for the production of better and safer drugs."
The researchers report that fungal-based protein expression systems are safer than conventional mammalian cell culture systems, but have not been effective in replicating complex human glycoprotein structures,until now.
"Demonstrating for the first time the production of 'hybrid' glycosylation structures in yeast brings GlycoFi an important step closer to dramatically improving the capacity and cost of producing therapeutic proteins," said Tillman Gerngross, Dartmouth engineering professor, co-founder and chief scientific officer of GlycoFi, and one of the authors on the paper. "In fact, we have already gone beyond this work and expect to manufacture fully complex human glycoproteins in one of our fungal production systems before the year's end."
Dartmouth/GlycoFi scientists genetically engineered the yeast P. pastoris to perform a series of sequential reactions that mimic the early processing of proteins in humans. After eliminating non-human glycosylation from the yeast, several genes were inserted into the yeast in such a way that the yeast synthesised new human-like glycosylation structures.
"The glycosylation structures we are seeing in our yeast are of a purity and uniformity unprecedented in biopharmaceutical manufacturing," said Stefan Wildt, also a Dartmouth engineering professor, director of strain development at GlycoFi, and another author of the paper. "This will allow GlycoFi to harness the inherent advantages of fungal protein expression systems and thereby address the biopharmaceutical manufacturing industry's capacity issues."