Biotech Rice to Prevent Hypertension

Eating rice to prevent hypertension? The idea seems far fetched, but not unlikely. Researchers from Japan have  developed transgenic rice accumulating significant levels of the anti-hypertensive proteins gamma-aminobutyric acid (GABA) and nicotianamine (NA). Hypertension is the leading cause of cardiovascular disease and cerebral stroke, affecting more than one billion individuals worldwide.

Kazuhito Akama and colleagues from Shimame University developed rice lines that express increased levels of the four-carbon amino acid GABA. GABA, an inhibitory neurotransmitter in mammalian central nervous system, has been shown to lower blood pressure in animals. A modified form of the gene that encodes for glutamate decarboxylase (GAD), under the control of the rice glutelin promoter (GluB-1), was introduced to rice cells via Agrobacterium-mediated transformation.

Kanako Usuda and colleagues, on the other hand, developed rice plants that produce the ACE inhibitor nicotianamine (NA). ACE or angiotensin I-converting enzyme is a key enzyme in hypertension and studies have shown that inhibition of its activity leads to reduced blood pressure. ACE inhibitors are widely accepted as the drugs of first choice for patients with hypertension and congestive heart failure. The scientists found that the ACE inhibitory activity of the transgenic rice-derived NA is very strong, even when compared with commercially available antihypertensive peptides. To minimize public anxiety over the GM rice, the selectable marker genes for antibiotic resistance were removed using the Cre/loxP DNA excision system.

The work of Akama and colleagues appears in the current issue of Transgenic Research. It is available at http://dx.doi.org/10.1007/s11248-009-9272-1 The Plant Biotechnology Journal, on the other hand, published the work of Usuda and colleagues. Read the paper at http://dx.doi.org/10.1111/j.1467-7652.2008.00374.x