The Potential Impact of CRISPR-Cas9 Gene Editing on Controlling Chagas Disease

The principal vector of Chagas disease, a serious public health hazard in Central and South America as well as the southern United States, is also known as triatomine bugs. Controlling the organisms that carry the parasite is crucial to halting the potentially fatal disease's spread, as there are currently few effective treatment options.

For the first time, CRISPR-Cas9 gene editing is used in kissing bugs in new research by an international team that includes a Penn State researcher. This opens the door to further studies on practical methods for controlling Chagas disease. Their findings were published in The CRISPR Journal.

“People have tried to do CRISPR and genetic engineering in triatomine bugs for a long time, but no one has been able to do it because traditional methods are very difficult in these bugs,” said Jason Rasgon, Dorothy Foehr Huck and J. Lloyd Huck Endowed Chair in Disease Epidemiology and Biotechnology and Co-Author of the study.

For the last six years, we have been developing tools to genetically modify difficult organisms. Here, we showed that you could genetically modify this vector insect. Our technology has the potential to make gene editing more efficient, easier, and cheaper in a wide range of animals.”

Jason Rasgon, Dorothy Foehr Huck and J. Lloyd Huck Endowed Chair, Disease Epidemiology and Biotechnology, The Pennsylvania State University

When it comes to gene editing, scientists usually use a procedure known as “embryonic microinjections,” in which they directly inject embryos with CRISPR gene editing material. However, there is no assurance that the genetic engineering process will be successful, and the method can be inefficient and costly. In kissing bugs, this method is challenging due to the toughness of their eggs, making them difficult to penetrate.

Instead, we have developed a technology — Receptor-Mediated Ovary Transduction of Cargo or ‘ReMOT Control’ — where you can inject the materials directly into the circulatory system of the mother and guide that material to the developing eggs, it is the equivalent of injecting every single egg in her body all at the same time.”

Jason Rasgon, Department of Entomology, The Pennsylvania State University

The team aimed to conduct a proof-of-concept study using triatomine bugs to test the ReMOT Control technology, focusing on genes associated with the color of the bugs' cuticle (outer covering) and their eyes.

Scientists injected female kissing bugs and then examined their offspring to observe any changes in the color of their eyes or cuticles. The visible changes confirmed that the targeted genes had been successfully deleted through genetic editing.

The researchers also noted that kissing bugs could serve as a model system for studying insect physiology. They believe that the development of this new protocol will allow scientists to investigate fundamental biological questions about insect behavior and disease transmission.

This has important implications for basic research, but it also brings triatomine bugs and Chagas disease into conversations about genetic technologies for the control of vector-borne pathogens, we are on the cusp of having the technology and tools available to be able to do that.”

Jason Rasgon, Department of Entomology, The Pennsylvania State University