Collaborative project targets cellular signals driving disease transmission in blood-feeding pests

University of Idaho scientists are part of a research team that will compare how cells in mosquitoes and ticks pass along messages, which could lead to common methods for controlling both pests.

Shirley Luckhart, a professor in U of I’s Department of Entomology, Plant Pathology and Nematology (EPPN) and Department of Biological Sciences, is a principal investigator on a four-year, $2.7 million Department of Defense (DOD) grant to evaluate similarities and differences between a pair of ancient signaling pathways in the cells of both blood-feeders. The project will also analyze how these pathways affect transmission of important disease-causing microbes.

A cellular signaling pathway is like a relay system inside a cell. It starts when a signal, such as a hormone or chemical, binds to a receptor on the cell surface. This triggers a chain of events inside the cell, passing the message specific to that signal through different molecules. When the signal reaches the target — usually the DNA, it causes a cellular response, such as turning on genes. In the case of ticks or mosquitoes, this may result in a change in the pest’s behavior and ability to transmit disease-causing microbes.

“Vector-borne diseases have always been a major interest of the U.S. military because of deployments to regions of the world where these diseases present a huge problem, as well as to the civilian workforce surrounding the military,” said Luckhart, who is also co-director of the Institute for Health in the Human Ecosystem (IHHE).

Ed Lewis, an EPPN professor and co-director of the IHHE, and postdoctoral fellow Kevin Ochwedo are also representing U of I on the project. Other collaborators include the research teams of Stephen Dumler, a professor in the Department of Pathology at Uniformed Services University (USU) in Bethesda, Maryland, and Utpal Pal, an entomology professor with the University of Maryland.

Luckhart has extensively studied signaling pathways that allow mosquitoes to draw information from hosts’ blood. She was struck by similarities between her own work and Pal’s upon learning of his research on ticks — a species that is extremely difficult to study and has received relatively little attention from scientists.

“I read some really interesting work Utpal published within the last couple of years and I thought, ‘Wow, it’s going in the same direction that we’re working on in mosquitoes right now,’” Luckhart said. “It’s always bugged me: ‘Why aren’t we working together on these things?’”

Luckhart’s expertise is in molecular and cellular biology. Lewis is an expert in behavioral biology and will devise experiments delving into how signaling pathways regulate mosquito behavior. Ochwedo will study how the signaling pathways affect behavior and physiology, and he also has a background in mosquitoes and malaria. Dumler will evaluate host responses to tick-borne pathogens, and Pal will analyze interactions between ticks and pathogens they may harbor.

Luckhart’s ties with USU researchers date back to the mid-1990s, when she worked as a postdoctoral researcher at the Walter Reed Army Institute of Research and had an adjunct appointment with USU. Throughout the years, she’s also led several collaborative grants involving colleagues from both institutions.

The research has ramifications for human health. The pathways Luckhart and her colleagues will be evaluating are also present in humans, and the findings should shed light on how they evolved in primitive organisms. Furthermore, ticks are primary vectors of Lyme disease, and mosquitoes can spread malaria. The U.S. military often encounters both pests during deployments.

“From a practical standpoint, we proposed, ‘Wouldn’t it be interesting if we found out that there was enough shared biology between ticks and mosquitoes that we might be able to develop some very similar strategies for interventions, leveraging very similar biology in these two distantly separated hosts?’” Luckhart said.