Wolbachia introduction into Lutzomyia longipalpis (Diptera: Psychodidae) cell lines and its effects on immune-related gene expression and interaction with Leishmania infantum

Abstract

BackgroundThe leishmaniases are important neglected diseases caused by Leishmania spp. which are transmitted by sand flies, Lutzomyia longipalpis being the main vector of visceral leishmaniasis in the Americas. The methodologies for leishmaniasis control are not efficient, causing 1.5 million reported cases annually worldwide, therefore showing the need for development of novel strategies and interventions to control transmission of the disease. The bacterium Wolbachia pipientis is being used to control viruses transmitted by mosquitoes, such as dengue and Zika, and its introduction in disease vectors has been effective against parasites such as Plasmodium. Here we show the first successful establishment of Wolbachia into two different embryonic cell lines from L. longipalpis, LL-5 and Lulo, and analysed its effects on the sand fly innate immune system, followed by in vitro Leishmania infantum interaction.ResultsOur results show that LL-5 cells respond to wMel and wMelPop-CLA strains within the first 72 h post-infection, through the expression of antimicrobial peptides and inducible nitric oxide synthase resulting in a decrease of Wolbachia detection in the early stages of infection. In subsequent passages, the wMel strain was not able to infect any of the sand fly cell lines while the wMelPop-CLA strain was able to stably infect Lulo cells and LL-5 at lower levels. In Wolbachia stably infected cells, the expression of immune-related genes involved with downregulation of the IMD, Toll and Jak-Stat innate immune pathways was significantly decreased, in comparison with the uninfected control, suggesting immune activation upon Wolbachia transinfection. Furthermore, Wolbachia transinfection did not promote a negative effect on parasite load in those cells.ConclusionsInitial strong immune responses of LL5 cells might explain the inefficiency of stable infections in these cells while we found that Lulo cells are more permissive to infection with Wolbachia causing an effect on the cell immune system, but not against in vitro L. infantum interaction. This establishes Lulo cells as a good system for the adaptation of Wolbachia in L. longipalpis.Electronic supplementary materialThe online version of this article (10.1186/s13071-018-3227-4) contains supplementary material, which is available to authorized users.

Wolbachia host shifts: routes, mechanisms, constraints and evolutionary consequences

“…Similarly, the high abundance of Wolbachia in pollen and broods of a carpenter bee (Ceratina calcarata) (McFrederick & Rehan, 2016), and the existence of identical Wolbachia strains in a hoverfly species (Merodon luteihumerus) and its host plant's bulb tissue (sea squill) suggested plants as a plausible platform for Wolbachia transmission in this system (Zori c, Ståhls, & Đan, 2019). As a result of plant-mediated host shifts, taxonomically diverse arthropod species feeding on the same plants may share common or closely related Wolbachia strains, as has been reported for the agricultural setting of a pumpkin farm (Sintupachee et al, 2006). Sharing a common host plant may also explain high host-shift rates among various species of fig wasps (Shoemaker et al, 2002;Yang et al, 2013).…”

“…Conversely, a given host usually does not react in the same way to all Wolbachia strains [e.g. the different immune response of A. aegypti or Lutzomyia longipalpis to w Mel and w MelPop‐CLA strains (Rancès et al ., 2012; da Silva Gonçalves et al ., 2019)]. In response to the severity of the fitness cost of Wolbachia infection, such strain‐specific host reactions can be selected in a very short evolutionary timescales (Li et al ., 2018).…”

“…The host-switching ability of Wolbachia has also been corroborated by artificial transfer of the bacteria across species through so-called 'transinfection' experiments (reviewed in . Taken together, the available evidence indicates that Wolbachia has a great ability to move between host species (Heath et al, 1999;Cordaux et al, 2001;Huigens et al, 2004a;Sintupachee et al, 2006;Baldo et al, 2008;Russell, 2012).…”

The effect of the endosymbiont Wolbachia on the behavior of insect hosts

“…This indicates that Wolbachia have the potential to influence host behaviors. In addition to the nervous tissues, Wolbachia also infect many other somatic tissues such as the gut, salivary glands, fat body, hemocytes, and Malpighian tubules of their hosts where they may affect host immunity and behavior (Dobson et al, 1999;Casper-Lindley et al, 2011;Albertson et al, 2013;Rohrscheib et al, 2015;Pietri et al, 2016;Pan et al, 2018;Saijo et al, 2018;Da Silva Gonçalves et al, 2019). Furthermore, Wolbachia has been found in muscle and wing tissue of some host species (Andersen et al, 2012).…”

Towards a Sustainable Vector-Control Strategy in the Post Kala-Azar Elimination Era

“…argentipes by transforming these bacteria to express anti-leishmania molecules ( Hillesland et al., 2008 ). Further, Wolbachia , an intracellular symbiont bacterium that has been previously used for effective control of mosquitoes ( Moreira et al., 2009 ; Walker et al., 2011 ; Caragata et al., 2016 ; Dutra et al., 2016 ; O’Neill, 2018 ; Pereira et al., 2018 ), has been recently reported from sand flies ( Da Silva Goncalves et al., 2019 ; Vivero et al., 2019 ). In-depth knowledge of the composition of gut microbiota from field-collected Ph.…”