RNA interference-mediated depletion of N-ethylmaleimide sensitive fusion protein and synaptosomal associated protein of 25 kDa results in the inhibition of blood feeding of the Gulf Coast tick, Amblyomma maculatum.

The signalling pathways in tick salivary glands that control 'sialo-secretome' secretion at the tick-host interface remain elusive; however, this complex process is essential for successful feeding and manipulation of the host haemostatic response. Exocytosis of the sialo-secretome in the salivary glands requires a core of soluble N-ethylmaleimide-sensitive fusion (NSF) attachment proteins (SNAPs) and receptor proteins (SNAREs). SNAREs have been identified as the key components in regulating the sialo-secretome in the salivary gland cells. In this study, we utilized RNA interference to investigate the functional role of two Amblyomma maculatum SNARE complex proteins, AmNSF and AmSNAP-25, in the tick salivary glands during extended blood feeding on the vertebrate host. Knock-down of AmNSF and AmSNAP-25 resulted in death, impaired feeding on the host, lack of engorgement and inhibited oviposition in ticks. Depletion also led to important morphological changes in the collapse of the Golgi apparatus in the salivary gland cells. Our results imply a functional significance of AmNSF and AMSNAP-25 in prolonged tick feeding, and survival on the host. Further characterization of the factors that regulate exocytosis may lead to novel approaches to prevent tick-borne diseases.