Second door discovered in war against mosquito-borne diseases

Michigan State University Today: In the global war against disease-carrying mosquitoes, scientists have long believed that a single molecular door was the key target for insecticide. This door, however, is closing, giving mosquitoes the upper hand.

In this week’s Proceedings of the National Academy of Sciences, a team of researchers led by Michigan State University has discovered a second gateway that could turn the tide against the mosquitoes’ growing advantage.

For many years, pyrethroid insecticides have been deployed in developing countries to fend off diseases such as malaria, dengue fever and more. They’re so effective that they are the only insecticides the World Health Organization uses with their mosquito nets they distribute around the globe.

“Pyrethroids are effective because they eliminate mosquitoes while having few if any side effects on humans,” said Yuzhe Du, MSU electrophysiologist and one of the lead authors. “Our discovery of a second receptor in the mosquitoes’ sodium channel gives us a better understanding of how the insecticide works at a molecular level as well as could lead to ways to stem mosquitoes’ resistance to pyrethroids.”

...In the last decade, growing resistance in mosquitoes has been detected in many countries. At the molecular level, resistance appears as mutations in the primary receptor in the sodium channel that allow mosquitoes to survive exposure to the insecticide. The discovery of the second receptor in the sodium channel, however, opens up more avenues to increase pyrethroids’ effectiveness.

“One of the keys to the success of this research was our cloning of a mosquito sodium channel for the first time,” said Ke Dong, MSU insect toxicologist and neurobiologist and the paper’s senior author. “Another lead author of this study, Yoshiko Nomura, dedicated nearly one year to make this happen, which allowed Dr. Du to perform electrophysiological experiments with the clone.”...

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