Faculty Opinions recommendation of An Ixodes scapularis protein required for survival of Anaplasma phagocytophilum in tick salivary glands.

Anaplasma phagocytophilum is the agent of human anaplasmosis, the second most common tick-borne illness in the United States. This pathogen, which is closely related to obligate intracellular organisms in the genera Rickettsia, Ehrlichia, and Anaplasma, persists in ticks and mammalian hosts; however, the mechanisms for survival in the arthropod are not known. We now show that A. phagocytophilum induces expression of the Ixodes scapularis salp16 gene in the arthropod salivary glands during vector engorgement. RNA interference–mediated silencing of salp16 gene expression interfered with the survival of A. phagocytophilum that entered ticks fed on A. phagocytophilum–infected mice. A. phagocytophilum migrated normally from A. phagocytophilum–infected mice to the gut of engorging salp16-deficient ticks, but up to 90% of the bacteria that entered the ticks were not able to successfully infect I. scapularis salivary glands. These data demonstrate the specific requirement of a pathogen for a tick salivary protein to persist within the arthropod and provide a paradigm for understanding how Rickettsia-like pathogens are maintained within vectors.

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Ixodes scapularis salivary gland protein P11 facilitates migration of Anaplasma phagocytophilum from the tick gut to salivary glands

EMBO Reports ◽

10.1038/embor.2011.177 ◽

2011 ◽

Vol 12 (11) ◽

pp. 1196-1203 ◽

Cited By ~ 26

Author(s):

Lei Liu ◽

Sukanya Narasimhan ◽

Jianfeng Dai ◽

Lili Zhang ◽

Gong Cheng ◽

...

Keyword(s):

Salivary Gland ◽

Salivary Glands ◽

Anaplasma Phagocytophilum ◽

Ixodes Scapularis ◽

Salivary Gland Protein

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Water absorption through salivary gland type I acini in the blacklegged tick, Ixodes scapularis

PeerJ ◽

10.7717/peerj.3984 ◽

2017 ◽

Vol 5 ◽

pp. e3984 ◽

Cited By ~ 8

Author(s):

Donghun Kim ◽

Paulina Maldonado-Ruiz ◽

Ludek Zurek ◽

Yoonseong Park

Keyword(s):

Water Absorption ◽

Salivary Glands ◽

Ixodes Scapularis ◽

Blood Feeding ◽

Type I ◽

Atpase Inhibitor ◽

Excess Water ◽

Long Duration ◽

Tick Salivary Glands ◽

Gland Type

Tick salivary glands play critical roles in maintaining water balance for survival, as they eliminate excess water and ions during blood feeding on hosts. In the long duration of fasting in the off-host period, ticks secrete hygroscopic saliva into the mouth cavity to uptake atmospheric water vapor. Type I acini of tick salivary glands are speculated to be involved in secretion of hygroscopic saliva based on ultrastructure studies. However, we recently proposed that type I acini play a role in resorption of water/ions from the primary saliva produced by other salivary acini (i.e., types II and III) during the tick blood feeding phase. In this study, we tested the function of type I acini in unfed female Ixodes scapularis. The route of ingested water was tracked after forced feeding of water with fluorescent dye rhodamine123. We found that type-I acini of the salivary glands, but not type II and III, are responsible for water uptake. In addition, the ingestion of water through the midgut was also observed. Injection or feeding of ouabain, a Na/K-ATPase inhibitor, suppressed water absorption in type I acini. When I. scapularis was offered a droplet of water, ticks rarely imbibed water directly (5%), while some approached the water droplet to use the high humidity formed in the vicinity of the droplet (23%). We conclude that during both on- and off-host stages, type I acini in salivary glands of female Ixodes scapularis absorb water and ions.

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Anaplasma phagocytophilum Inhibits Apoptosis and Promotes Cytoskeleton Rearrangement for Infection of Tick Cells

Infection and Immunity ◽

10.1128/iai.00194-13 ◽

2013 ◽

Vol 81 (7) ◽

pp. 2415-2425 ◽

Cited By ~ 44

Author(s):

Nieves Ayllón ◽

Margarita Villar ◽

Ann T. Busby ◽

Katherine M. Kocan ◽

Edmour F. Blouin ◽

...

Keyword(s):

Salivary Glands ◽

Anaplasma Phagocytophilum ◽

Ixodes Scapularis ◽

Content Type ◽

Granulocytic Anaplasmosis ◽

New Genes ◽

Voltage Dependent ◽

Selective Channel ◽

Cytoskeleton Rearrangement

ABSTRACTAnaplasma phagocytophilumcauses human granulocytic anaplasmosis. Infection with this zoonotic pathogen affects gene expression in both the vertebrate host and the tick vector,Ixodes scapularis. Here, we identified new genes, including spectrin alpha chain or alpha-fodrin (CG8) and voltage-dependent anion-selective channel or mitochondrial porin (T2), that are involved inA. phagocytophiluminfection/multiplication and the tick cell response to infection. The pathogen downregulated the expression of CG8 in tick salivary glands and T2 in both the gut and salivary glands to inhibit apoptosis as a mechanism to subvert host cell defenses and increase infection. In the gut, the tick response to infection through CG8 upregulation was used by the pathogen to increase infection due to the cytoskeleton rearrangement that is required for pathogen infection. These results increase our understanding of the role of tick genes duringA. phagocytophiluminfection and multiplication and demonstrate that the pathogen uses similar strategies to establish infection in both vertebrate and invertebrate hosts.

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Dissecting Flavivirus Biology in Salivary Gland Cultures from Fed and Unfed Ixodes scapularis (Black-Legged Tick)

mBio ◽

10.1128/mbio.02628-18 ◽

2019 ◽

Vol 10 (1) ◽

pp. e02628-18 ◽

Cited By ~ 4

Author(s):

Jeffrey M. Grabowski ◽

Olof R. Nilsson ◽

Elizabeth R. Fischer ◽

Dan Long ◽

Danielle K. Offerdahl ◽

...

Keyword(s):

Salivary Glands ◽

Cellular Localization ◽

Ixodes Scapularis ◽

Blood Feeding ◽

The United States ◽

Embryonic Cells ◽

Content Type ◽

Virus Like Particles ◽

Powassan Virus ◽

Tick Salivary Glands

ABSTRACT The Ixodes scapularis tick transmits a number of pathogens, including tick-borne flaviviruses (TBFVs). In the United States, confirmed human infections with the Powassan virus (POWV) TBFV have a fatality rate of ∼10% and are increasing in incidence. Tick salivary glands (SGs) serve as an organ barrier to TBFV transmission, and little is known regarding the location of TBFV infection in SGs from fed ticks. Previous studies showed I. scapularis vanin (VNN) involved with TBFV infection of I. scapularis ISE6 embryonic cells, suggesting a potential role for this gene. The overall goal of this study was to use SG cultures to compare data on TBFV biology in SGs from fully engorged, replete (fed) ticks and from unfed ticks. TBFV multiplication was higher in SGs from fed ticks than in those from unfed ticks. Virus-like particles were observed only in granular acini of SGs from unfed ticks. The location of TBFV infection of SGs from fed ticks was observed in cells lining lobular ducts and trachea but not observed in acini. Transcript knockdown of VNN decreased POWV multiplication in infected SG cultures from both fed and unfed ticks. This work was the first to identify localization of TBFV multiplication in SG cultures from a fed tick and a tick transcript important for POWV multiplication in the tick SG, an organ critical for TBFV transmission. This research exemplifies the use of SG cultures in deciphering TBFV biology in the tick and as a translational tool for screening and identifying potential tick genes as potential countermeasure targets. IMPORTANCE Tick-borne flaviviruses (TBFVs) are responsible for more than 15,000 human disease cases each year, and Powassan virus lineage 2 (POWV-L2) deer tick virus has been a reemerging threat in North America over the past 20 years. Rapid transmission of TBFVs in particular emphasizes the importance of preventing tick bites, the difficulty in developing countermeasures to prevent transmission, and the importance of understanding TBFV infection in tick salivary glands (SGs). Tick blood feeding is responsible for phenomenal physiological changes and is associated with changes in TBFV multiplication within the tick and in SGs. Using SG cultures from Ixodes scapularis female ticks, the primary aims of this study were to identify cellular localization of virus-like particles in acini of infected SGs from fed and unfed ticks, localization of TBFV infection in infected SGs from fed ticks, and a tick transcript (with associated metabolic function) involved in POWV-L2 infection in SG cultures.

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An efficient microinjection method to generate human anaplasmosis agent Anaplasma phagocytophilum-infected ticks

Scientific Reports ◽

10.1038/s41598-020-73061-9 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Vikas Taank ◽

Ellango Ramasamy ◽

Hameeda Sultana ◽

Girish Neelakanta

Keyword(s):

Anaplasma Phagocytophilum ◽

Ixodes Scapularis ◽

In Vitro Cultures ◽

Transmission Dynamics ◽

Tick Feeding ◽

Nymphal Stage ◽

Bacterial Colony ◽

Obligate Intracellular ◽

Transstadial Transmission

Abstract Ticks are important vectors that transmit several pathogens including human anaplasmosis agent, Anaplasma phagocytophilum. This bacterium is an obligate intracellular rickettsial pathogen. An infected reservoir animal host is often required for maintenance of this bacterial colony and as a source for blood to perform needle inoculations in naïve animals for tick feeding studies. In this study, we report an efficient microinjection method to generate A. phagocytophilum-infected ticks in laboratory conditions. The dense-core (DC) form of A. phagocytophilum was isolated from in vitro cultures and injected into the anal pore of unfed uninfected Ixodes scapularis nymphal ticks. These ticks successfully transmitted A. phagocytophilum to the murine host. The bacterial loads were detected in murine blood, spleen, and liver tissues. In addition, larval ticks successfully acquired A. phagocytophilum from mice that were previously infected by feeding with DC-microinjected nymphal ticks. Transstadial transmission of A. phagocytophilum from larvae to nymphal stage was also evident in these ticks. Taken together, our study provides a timely, rapid, and an efficient method not only to generate A. phagocytophilum-infected ticks but also provides a tool to understand acquisition and transmission dynamics of this bacterium and perhaps other rickettsial pathogens from medically important vectors.

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