Expression plasticity of Phlebotomus papatasi salivary gland genes in distinct ecotopes through the sand fly season

Abstract

BackgroundSand fly saliva can drive the outcome of Leishmania infection in animal models, and salivary components have been postulated as vaccine candidates against leishmaniasis. In the sand fly Phlebotomus papatasi, natural sugar-sources modulate the activity of proteins involved in meal digestion, and possibly influence vectorial capacity. However, only a handful of studies have assessed the variability of salivary components in sand flies, focusing on the effects of environmental factors in natural habitats. In order to better understand such interactions, we compared the expression profiles of nine P. papatasi salivary gland genes of specimens inhabiting different ecological habitats in Egypt and Jordan and throughout the sand fly season in each habitat.ResultsThe majority of investigated genes were up-regulated in specimens from Swaymeh late in the season, when the availability of sugar sources is reduced due to water deprivation. On the other hand, these genes were not up-regulated in specimens collected from Aswan, an irrigated area less susceptible to drought effects.ConclusionExpression plasticity of genes involved with vectorial capacity in disease vectors may play an important epidemiological role in the establishment of diseases in natural habitats.

Profiling of Human Acquired Immunity Against the Salivary Proteins of Phlebotomus papatasi Reveals Clusters of Differential Immunoreactivity

“…The lack of expression of an ∼21 kDa protein (Figure 1B) by our Israeli colony of P. papatasi could be because of differential salivary gene expression between variant vector populations, especially given the seasonal and regional differences in expression of select salivary protein transcripts 15. Moreover, differences in post-translational modifications of salivary proteins, such as glycosylation or phosphorylation patterns,44 between the Tunisian and Israeli colonies may have led to differences in protein identification and even antibody specificities.…”

“…Table 1 shows regional donor profiles. Geospatial coordinates for these regions were as previously described 15. Each site was selected based on ecological characteristics in Jordan16–23 and Egypt24–29 pertaining to active cases of leishmaniasis transmission and the presence of P. papatasi vectors.…”

Impact of insect salivary proteins in blood feeding, host immunity, disease, and in the development of biomarkers for vector exposure

“…As drought reduces sugar content produced by plants, insect vectors need to bear special adaptations in order to obtain a sugar meal (reviewed in [16]). In the sand fly P. papatasi , up-regulation of five transcripts encoding for secreted salivary gland proteins are only observed in sand flies caught during the dry season [18]. This plasticity in salivary gland gene expression seems also to be associated with the transmission of Leishmania , which is more prevalent in the dry season [16,19].…”

Sand fly saliva: toward a vaccine against leishmaniases

“…The saliva components are not constant in sand flies with different species, sex, age, generation and physiological stages [32][33][34]. Environmental factors and geographical locations seem to affect the saliva composition [35,36].…”

“…The salivary glands have a unicellular epithelial layer surrounding a container for the saliva which consists of a repertoire of proteins that vary upon parameters such as the physiological state of the adult insect as well as its sex, age, generation, species and geographical location [41,32]. Moreover, the saliva composition has been shown to change upon the environmental conditions of the sand fly habitats [36]. After emerging, the number of protein components gradually increase with the age of the insect, reaching to the full amount in 3 to 5-day-old sand flies.…”