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Taking a bite out of the bed bug sialome
phorin, a heme-containing protein that transports the vasodilator nitric oxide. Surprisingly, acetylcholinesterase, an Once the scourge of seedy hotels and enzyme that degrades the neurotransflophouses, bed bugs are scurrying into mitter acetylcholine, was strongly exnew quarters, and even luxury pentpressed in bed bug saliva. “It’s a puzzle houses in New York City’s Upper East to me why acetylcholinesterase is there,” Side are within their reach. The city, like says Ribeiro. “During the evolution to several other urban centers, has seen a blood feeding, it’s almost like you make resurgence in bed bug infestations, a lottery of your genome and try to sewhich has sparked renewed scientific crete every protein in saliva interest in the bloodsucking to see if it has a beneficial pests. To gain a better uneffect.” Ribeiro plans further derstanding of the evoluexperiments to investigate tionary adaptations that the functions of the more allow some arthropods enigmatic proteins, includsuch as bedbugs to feed on ing some novel sequences, blood, Jose´ Ribeiro and coin bed bug saliva. workers at the National InIn addition to providing stitute of Allergy and Infecinsights into bed bug evolutious Disease, Rocky tion, Ribeiro’s findings Mountain Laboratories, and could have practical applithe University of Kentucky cations. “Many times paidentified salivary proteins tients go to the doctor with (the so-called sialome) of pustules or allergic reactions the common bed bug, Ciof unknown origin,” says mex lectularius. They report Ribeiro. “They deny that their results in a new JPR Don’t let the bed bugs bite. C. lectularius ingests a blood meal from a they have bed bugs in their paper (DOI 10.1021/ human host. CDC/Harvard University, Dr. Gary Alpert; Dr. Harold Harlan; house, but often that’s the pr1000169). Richard Pollack. Photo Credit: Piotr Naskrecki case. Our results could be In the 1940s and 50s, used to create a simple test bed bugs were largely to detect if the person has eradicated in the U.S. The ability to feed on blood arose antibodies against bed bug salivary prothrough widespread use of the insectiindependently multiple times during teins.” cide DDT. But after the U.S. Environevolution, and organisms evolved rePhilip Koehler at the University of mental Protection Agency banned DDT markably different strategies to do so. Florida notes that knowledge of the bed in 1972, bed bugs began to make a slow When parasites are forced to switch bug sialome could assist in developing but steady resurgence. In the mid-2000s, hosts or when hosts develop antibodallergy desensitization vaccines for complaints about infestations in New ies to salivary components, the people who suffer severe reactions to York City, London, and other large cities blood-feeding organism must adapt bed bug bites. “This is a significant piece skyrocketed, and the pests began showto changing circumstances. As a reof research that has been needed since ing up in unlikely places such as hospisult, even two species of mosquitoes the resurgence of bed bugs throughout tals, theaters, expensive hotels, and affluthat share a common ancestor can the world,” he says. “It will serve as a ent neighborhoods. have unique sialomes. resource for future studies on the effects Emerging from household crevices to Ribeiro and others have investigated and treatment of bed bug bites.” feed primarily at night, the flattened, the sialomes of mosquitoes, ticks, and Not only that, “Blood-feeding arthropod reddish-brown insects leave behind itchy fleas, but nobody had examined the saliva is a rich source of pharmacologically welts on their sleeping hosts. Because composition of bed bug saliva. After active molecules,” says Stephen Wikel at bed bugs are not known vectors for any characterizing the transcriptome of the the University of Texas Medical Branch. human disease, they are considered salivary glands of C. lectularius, Ribeiro “These sialomes are potentially very valumore of a nuisance than a serious health and colleagues analyzed the proteome able sources for drug discovery.” In other threat. Nonetheless, the bites can cause of bed bug saliva by 1DE and LC/MS/ words, someday the bed bug could prove intense itching and discomfort for those MS. A total of 46 proteins were identiitself more than just an itchy nuisance by allergic to C. lectularius saliva. fied. Although some proteins were providing leads for new drugs such as anThe saliva of blood-feeding arthropods common to the sialomes of other ticoagulants, vasodilators, and pain and is a complex concoction of vasodilators, blood-feeding arthropods, others were itch inhibitors. Until then, sleep tight. anti-clotting agents, and anesthetics that, unique to C. lectularius, such as nitro—Laura Cassiday when injected into the host during feed-
10.1021/pr1006284
ing, keep the blood flowing and compromise immune defenses. The human body possesses many overlapping mechanisms to prevent blood loss, collectively known as hemostasis. “Because there is such a redundant system in hemostasis, you cannot have a magic bullet to disarm it,” says Ribeiro. “You need to have a magic potion, and that’s what bloodsucking arthropods have in their saliva.”
© 2010 American Chemical Society
Journal of Proteome Research • Vol. 9, No. 8, 2010 3765
