Laboratory modified corn has shown some progress in treating a rare, life-threatening childhood genetic disease. Researchers have been developing enzyme therapeutics for lysosomal storage diseases - rare but devastating childhood genetic diseases – for more than a decade. 

In the most severe forms of these inherited diseases, untreated patients die in early childhood because of progressive damage to all organs of the body and currently, enzyme treatments are available for only six of the more than 70 diverse types of lysosomal storage diseases.

Scientifically-engineered maize may become a platform for making alpha-L-iduronidase, an enzyme used to treat the lysosomal storage disease known as mucopolysaccharidosis I, according to research published in this week's Nature Communications.  Their technology manipulates processes inside the maize seed that "traffick" messenger RNAs to certain parts of the cell as a means of controlling the subsequent sugar processing of the therapeutic protein. 

In that way, researchers have been able to produce the enzyme drug in maize seeds. The product could ultimately be used as a disease therapeutic, although it is still early days - much would need to be accomplished before this can become a reality.

"In part because mammalian cell cultures have been the system of choice to produce these therapeutics, the enzymes are extremely costly to make, with treatments typically ranging from $300,000 to $500,000 per year for children, with even higher costs for adults," says Kermode, noting the strain on healthcare budgets in Canada and other countries is becoming an issue. "In 2005, we had the basis of our story worked out. Taking it to the next level involved their precise analyses to determine the sugar residues on the therapeutic enzyme produced by the modified maize seeds. 

"When we first looked at the sugar analysis data we were amazed at how well the 'mRNA-trafficking strategy' had worked, and the high fidelity of the process for controlling the sugar-processing of the therapeutic protein. This is critical as sugar processing influences the characteristics of a protein (enzyme) therapeutic, including its safety, quality, half-life in the bloodstream, and efficacy. The work could well extend to forming a platform for the production of other protein therapeutics."

Citation: Xu He, Thomas Haselhorst, Mark von Itzstein, Daniel Kolarich, Nicolle H. Packer, Tracey M. Gloster, David J. Vocadlo, Lorne A. Clarke, Yi Qian&Allison R. Kermode, 'Production of α-L-iduronidase in maize for the potential treatment of a human lysosomal storage disease', Nature Communications 3, Article number: 1062 doi:10.1038/ncomms2070