Entomologists Work Toward Mitigating the Spread of Lyme Disease by Unlocking Mechanisms Controlling the Black-legged Tick's Salivary Glands

Nervous system and salivary glands of a black-legged tick are shown with the colors stained for two different neuropeptides. Source: K-State department of entomology 

In research that could mitigate the spread of Lyme disease, KansasStateUniversity entomologists are looking for answers in tick saliva.

Yoonseong Park, associate professor of entomology at K-State, is working with Ladislav Simo, a research associate, to understand what controls the salivary gland system in black-legged ticks.

"My research program has focused on how the tick's neurological system is connected to the salivary system," Park said. "We have identified neuropeptides involved in controlling salivary gland activity."

Working in collaboration with K-State's Functional Genomics Consortium, Park and Simo have used the group's MALDI-TOF machine. Park said it is one of the most modern protein analysis machines available, and with it they have identified a number of neuropeptides for the first time. Understanding these neuropepties could help mitigate the spread of Lyme disease, Park said.

Also called deer ticks, black-legged ticks spread Lyme disease. Park said it affects between 250,000 and 350,000 people in the United States each year and also is a big problem in Europe. The bacteria that cause Lyme disease are transmitted through the tick's saliva when it is feeding on a host.

A tick's meal lasts about a week, Park said. During that time, neuropeptides control the salivary gland to keep the feeding process going. That means secreting anticoagulants to make the host's blood drinkable and secreting anti-immunoglobulins that inhibit the host's ability to resist the tick. Park said that the tick's salivary system is continually adjusting these secretions as needed.

The salivary system also plays a role in helping the tick survive when a host isn't available. Park said the tick uses its salivary gland to control the suction of water out of the atmosphere.

"Eventually, our study can be a tool for disrupting the disease transmission," Park said. "We might be able to inhibit the tick's salivary secretion mechanism."

He said that his research with Simo also will help scientists who are trying to understand such mechanisms in other tick species, like the species that spreads Rocky Mountain Spotted Fever.

Park said that his lab at K-State is one of few labs in the country studying the neuropeptides' role in the salivary system. Their research will be published in an upcoming issue of Cell and Tissue Research.

Park and Simo also are collaborating with Purdue University researchers who are sequencing the black-legged tick's genome. Park said that they have identified the genes responsible for encoding the neuropeptides.

Their research is being done with support from K-State's Center of Biomedical Research Excellence. Funded by the National Institutes of Health, the center provides resources to junior basic researchers and clinician-scientists at K-State and across Kansas.

Park's previous research through the center involved investigating the excretion processes in Anopheles gambaie, the mosquito that spreads malaria.