Ferritin 1 silencing effect in Rhipicephalus sanguineus sensu lato (Acari: Ixodidae) during experimental infection with Ehrlichia canis

Abstract

Rhipicephalus sanguineus sensu lato (s.l.) is a very common ectoparasite of domestic dogs able to transmit several pathogens of human and veterinary importance. Tick infestations and tick-borne diseases (TBDs) remain a serious and persistent problem, due to the lack of efficient control measures. It is therefore vital that novel approaches to control are pursued. Whilst vaccination is recognised as a potential control method to reduce tick infestation, no anti-R. sanguineus vaccine is available. Ticks depend on their blood meals to obtain nutrients and to achieve sexual maturity, which exposes them to vast amounts of iron. Although an essential molecule for several biological processes, its excess can lead to oxidative stress. Iron homeostasis is achieved with the help of iron-binding proteins called ferritins, among others, present in several tick tissues and developmental stages. These evolutionarily conserved proteins regulate iron homeostasis by storing and releasing iron in a controlled manner. In this study the R. sanguineus ferritin 1 gene was silenced through RNA interference (RNAi) in adult females exposed to an experimental infection with Ehrlichia canis. The purpose of this study was to assess the role of this protein in tick feeding, ovary development, oogenesis, and pathogen acquisition. Our data has shown that silencing ferritin 1 alters tick competence to normally engorge and causes morphologic and histochemical changes in the ovaries (OV) and oocytes. Furthermore, our data revealed that no E. canis DNA was found in either experimental group. Determining the function of molecules that act in key biological processes, such as blood digestion or reproduction, and that could be considered potential tick antigens will contribute towards the improvement of current control measures against these ectoparasites and the pathogens they vector.

Rhipicephalus bursa Sialotranscriptomic Response to Blood Feeding and Babesia ovis Infection: Identification of Candidate Protective Antigens

“…Babesiosis is one of the most important diseases transmitted by ticks that affect a wide range of vertebrates, considered an emerging zoonose (Hunfeld et al, 2008 ; Ord and Lobo, 2015 ; Antunes et al, 2017 ). B. ovis is a potentially lethal pathogen that is normally found in small ruminants, and it is primarily transmitted by R. bursa , a tick species that is widely distributed in the Mediterranean region (Walker et al, 2000 ; Ferrolho et al, 2016a ). Despite the importance of the R. bursa - B. ovis -vertebrate host interactome, no studies have examined these molecular relationships.…”

“…(Raele et al, 2015 ; Dahmani et al, 2016 ; Ferrolho et al, 2016b ), thus demonstrating its importance in animal health, particularly in livestock. B. ovis , an intraerythrocytic apicomplexan parasite, is the main etiological agent of ovine babesiosis, which is a tick-borne disease of small ruminants, and its geographical distribution overlaps with that of R. bursa (Walker et al, 2000 ; Ranjbar-Bahadori et al, 2012 ; Erster et al, 2015 ; Ferrolho et al, 2016a ). This highly pathogenic organism is characterized by low parasitaemia, and it causes severe infections (Habela et al, 1990 ; Sevinc et al, 2013 ; Hurtado et al, 2015 ).…”

Disruption of blood meal-responsive serpins prevents Ixodes scapularis from feeding to repletion

“…An important goal of this study was to determine the importance of the 11 serpins in tick feeding using RNAi silencing. The RNAi silencing approach is widely used to establish functions of tick genes in tick feeding physiology (Aljamali et al, 2003; Gao et al, 2011; Karim et al, 2005; Kim et al, 2014b; 2015a; 2015b; Mulenga and Khumthong, 2010a; 2010b; Mulenga et al, 2013b; Mulenga et al, 2010a; Mulenga et al, 2010b; Pedra et al, 2006; Radulović et al, 2015) and transmission of TBD agents (Adamson et al, 2013; Antunes et al, 2012; Coumou et al, 2016; Ferrolho et al, 2017; Kocan et al, 2009; Merino et al, 2011). Similar to other organisms (Garrett et al, 2009; Gulley et al, 2013; Reichhart et al, 2011; Tong et al, 2005), the tick serpin family is large with high potential for redundancy (Mulenga et al, 2009; Porter et al, 2015).…”

Transcriptome and Proteome Response of Rhipicephalus annulatus Tick Vector to Babesia bigemina Infection

“…× 33-gauge needle. The control group was injected with the same volume of elution buffer, similar to what has been described in other studies (Hussein et al, 2015; Ferrolho et al, 2017). While the use of unrelated dsRNA is now a well-established control in species with full genome annotation, the R. annulatus genome is not annotated thus increasing the possibility of off targets in silencing assays.…”