5 days ago
Yeast cells brew human DNase1 for first time, paving way for cheaper treatment
DNase1 is a powerful human enzyme that breaks down free DNA in the body. It plays a critical role in clearing thick mucus in cystic fibrosis patients.
For decades, scientists have relied on expensive production methods using immortalized hamster cells. But that could change, thanks to new research that shows the enzyme can be made using yeast cells instead.
A team from Ruhr University Bochum, led by Professor Beate Brand-Saberi and Dr. Markus Napirei, has successfully produced human DNase1 in yeast for the first time.
'This is the result of years of work, and could lay the groundwork for the manufacture of human DNase1 in yeast as a biological agent,' said Napirei.
The research team used the yeast fungus Pichia pastoris, a well-known system for producing therapeutic proteins.
They implanted lab-produced DNA into the yeast using an electric pulse. The yeast stably integrated the gene, read it, and began releasing human DNase1.
'The advantages of yeast over mammalian cells are cost-effective culture conditions, a high rate of reproduction without the need to immortalize cells, and lower susceptibility to pathogens,' explained Napirei.
Mammalian cells like those from hamster ovaries have been used for DNase1 production since 1993. However, they must be chemically or genetically altered to keep dividing indefinitely.
This immortalization adds complexity, cost, and time to the process.
Doctoral student Jan-Ole Krischek, under Napirei's and Professor Hans Georg Mannherz's supervision, was able to express, purify, and analyze the enzyme in yeast.
This marks the first time human DNase1 has been produced using this method.
Despite the success, researchers found that the yeast produced far less human DNase1 than expected. In comparison, it made more of a similar mouse version of the enzyme.
'This is partly due to the specific folding behaviors of the two proteins,' Napirei said.
Mouse DNase1 shares 82% of its primary structure with the human form. The team had used it as a model, but the structural differences affected production.
Human DNase1 is already in clinical use. It has been produced from hamster ovary cells for over three decades to treat cystic fibrosis.
The enzyme breaks down DNA in thick bronchial mucus, making it easier for patients to breathe and cough it out.
DNase1 also holds promise in other medical areas. It helps remove neutrophil extracellular traps (NETs), which the body uses to trap bacteria.
In diseases like sepsis or COVID-19, NETs can become overactive and form dangerous microthrombi.
'It could be useful to use DNase1 to better dissolve these microthrombi that contain DNA,' said Napirei.
Researchers are also exploring DNase1's role in treating strokes caused by blocked brain arteries.
Producing DNase1 in yeast could significantly lower costs and simplify manufacturing.
This could improve global access to treatments for cystic fibrosis and potentially open doors to new therapeutic uses.
With the groundwork now laid, further research may optimize yield and unlock broader medical applications.
Their findings were published in PLOS One.
