Receptor for advanced glycation end-product (RAGE) modulates
inflammation during tick infestation
Abstract
Ticks are notorious blood-sucking ectoparasites affecting both humans
and animals, and serve as a unique vector of various deadly diseases.
Ticks are pool feeder and extensive tissue damage is a common feature in
hosts’ skin during their feeding. Here, we have elegantly shown the
roles of the receptor for advanced glycation end-products (RAGE) during
repeated tick infestations. Initially (day1), ticks attached hypostome
into the skin making a notch on the epidermis associated with cellular
damage and infiltrations, and there were no hemorrhagic changes. In
advanced stages (day5), a large blood pool developed, which was flooded
with blood (RBC). The hemorrhagic zone was surrounded by the presence of
inflammatory cells. Very few inflammatory cells were detected around the
zone of hemorrhage in the primary infestation. In the primary
infestation, we found very few eosinophils up to day4 of feeding. At
day5 of post attachment, eosinophil infiltration a little bit increased
at the periphery of blood pool. Infiltrations of inflammatory cells
increased in the subsequent infestations and reached to the highest
level in the 3 rd infestation in wild type (wt) mice,
but not in RAGE-/- mice, which was comparable to the non-infested
control mouse skin. RAGE was highly expressed in the 3
rd infestation in wt mice. Interestingly, in the
tertiary infestation, infiltration of innate lymphoid cells type 2
(ILC2s), expression of S100A8 and S100B, and peripheral eosinophil
counts significantly increased at the biting sites of ticks in wt, but
not in RAGE -/- mice. Taken together, our study
revealed that RAGE-mediated inflammation and eosinophils played crucial
roles in the tick induced inflammatory reactions.