A Kunitz protease inhibitor from Dermacentor variabilis, a vector for spotted fever group rickettsiae, limits Rickettsia montanensis invasion.
A defining facet of tick-Rickettsia symbioses is the molecular strategy employed by each partner to ensure its own survival. Ticks must control rickettsial colonization to avoid immediate death. In the current study, we show that rickettsial abundance in the tick midgut increases once the expression of a Kunitz-type serine protease inhibitor from the American dog tick (Dermacentor variabilis) (DvKPI) is suppressed by small interfering RNA (siRNA). A series of in vitro invasion assays suggested that DvKPI limits rickettsial colonization during host cell entry. Interestingly, we observed that DvKPI associates with rickettsiae in vitro as well as in the tick midgut. Collectively, our data demonstrate that DvKPI limits host cell invasion by Rickettsia montanensis, possibly through an association with the bacterium.
Department of Microbiology and Immunology, University of Maryland, Baltimore, School of Medicine, 685 West Baltimore Street, Howard Hall Suite 380, Baltimore, Maryland 21201, USA. scera001@umaryland.edu
Shane M
SM
Ceraul
Ashley
A
Chung
Khandra T
KT
Sears
Vsevolod L
VL
Popov
Magda
M
Beier-Sexton
M Sayeedur
MS
Rahman
Abdu F
AF
Azad
D000818:Animals; D001179:Arthropod Vectors / Q000201:enzymology*; D002460:Cell Line; D003870:Dermacentor / Q000201:enzymology / Q000382:microbiology*; D041981:Gastrointestinal Tract / Q000201:enzymology / Q000382:microbiology; D054884:Host-Pathogen Interactions; D011480:Protease Inhibitors / Q000378:metabolism*; D034622:RNA Interference; D034741:RNA, Small Interfering; D012281:Rickettsia / Q000502:physiology*
D011480:Protease Inhibitors; D034741:RNA, Small Interfering