Medicine from moss: Bioreactor technique may offer hope to people with age-related blindness

Whereas insulin used to be extracted from slaughterhouse waste today it is produced genetically in bacteria. However, more complex proteins have to be synthesised in more complex organisms. This takes place mostly in bioreactors using animal cell lines. Biotechnologist Prof. Ralf Reski from Freiburg, Germany, has developed the moss Physcomitrella patens into a safe and inexpensive alternative supplier of medicine.

His group has now, under Dr. Eva Decker, for the first time succeeded in producing a human protein in a moss bioreactor, which has been assigned the "orphan drug" status by the respective EU authorities. This means the development and approval of such medication receive particular support from the authorities. In many people the amount of this protein decreases with old age -- with severe consequences. Eva Decker explains: "With the complement factor H we have produced a protein in moss that otherwise occurs only in blood and is important for the immune system. Not enough of this protein in older people is the main cause of blindness for 50 million people worldwide. This age-related macular degeneration (AMD) is a problem, particularly in industrialised countries."

Biochemists from the Freiburg Centre for Systems Biology under Dr. Andreas Schlosser were able to show with the help of high-performance mass spectrometers that the human factor H engineered into and produced by moss was a complete protein. Infection biologists headed by Prof. Peter F. Zipfel from the Hans-Knöll-Institute in Jena, Germany, were able to prove in biological assays that factor H from moss is fully functional. "Currently factor H is not available in pharmacies, so treatment for AMD with this protein is not possible. To date recombinant production of factor H was barely feasible. I am convinced that for the first time the moss bioreactor is a promising option," says Peter Zipfel.

This work was supported by the German Federal Ministry of Education and Research (BMBF), the Freiburg Initiative for Systems Biology and the Cluster of Excellence BIOSS.

Dr. Annette Büttner-Mainik, first author of the publication, was a Kekulé scholarship holder from the endowment fund of the German Chemical Industry (FCI).

"It will take a while before medication produced in moss is available in pharmacies," says Ralf Reski, member of the Innovation Think Tank of the governor of Baden-Wuerttemberg. "We are further optimising the moss bioreactor using methods from Systems Biology and Synthetic Biology. However, the implementation of clinical studies and the setting up of industrial production is long-winded and expensive; this is the task of industry and not of university research."