Phlebotomus perniciosus (Diptera: Phlebotominae) is a medically and veterinary important insect vector. It transmits the unicellular parasite Leishmania infantum that multiplies intracellularly in macrophages causing life-threatening visceral diseases. Leishmania establishment in the vertebrate host is substantially influenced by immunomodulatory properties of vector saliva that are obligatorily co-injected into the feeding site. The repertoire of P. perniciosus salivary molecules has already been revealed and, subsequently, several salivary proteins have been expressed. However, their immunogenic properties have never been studied. In our study, we tested three P. perniciosus recombinant salivary proteins-an apyrase rSP01 and yellow-related proteins rSP03 and rSP03B-and showed their anti-inflammatory nature on the murine bone-marrow derived macrophages. Even in the presence of pro-inflammatory stimuli (IFN-γ and bacterial lipopolysaccharide, LPS), all three recombinant proteins inhibited nitric oxide production. Moreover, rSP03 seems to have a very strong anti-inflammatory effect since it enhanced arginase activity, increased the production of IL-10, and inhibited the production of TNF-α even in macrophages stimulated with IFN-γ and LPS. These results suggest that P. perniciosus apyrase and yellow-related proteins may serve as enhancing factors in sand fly saliva, facilitating the development of Leishmania infection along with their anti-haemostatic properties. Additionally, rSP03 and rSP03B did not elicit the delayed-type hypersensitivity response in mice pre-exposed to P. perniciosus bites (measured as visible skin reaction). The results of our study may help to understand the potential function of recombinant's native counterparts and their role in Leishmania transmission and establishment within the host.

• Keywords
• Phlebotomus, apyrase, immunogenicity, macrophage polarization, sand fly saliva, yellow-related proteins,
• MeSH
• Anti-Inflammatory Agents MeSH
• Phenotype MeSH
• Macrophages MeSH
• Mice MeSH
• Phlebotomus * MeSH
• Dogs MeSH
• Recombinant Proteins MeSH
• Salivary Proteins and Peptides MeSH
• Animals MeSH
• Check Tag
• Mice MeSH
• Dogs MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Anti-Inflammatory Agents MeSH
• Recombinant Proteins MeSH
• Salivary Proteins and Peptides MeSH

BACKGROUND: During blood feeding, sand flies inoculate salivary proteins that interact with the host haemostatic system. The blocking of biogenic amines such as serotonin and histamine helps to limit vasodilatation and clot formation, and thus enables the insect to finish the blood-feeding process. In sand flies, an amine-binding ability is known only for the yellow-related proteins of Phlebotomus and Lutzomyia vectors, but not yet for members of the genus Sergentomyia. METHODS: The ability of Phlebotomus argentipes and Sergentomyia schwetzi recombinant yellow-related salivary proteins to bind histamine and serotonin was measured by microscale thermophoresis. Both sand fly species were also fed through a chicken-skin membrane on blood mixed with histamine or serotonin in order to check the effects of biogenic amines on sand fly fitness. Additionally, fecundity and mortality were compared in two groups of P. argentipes females fed on repeatedly-bitten and naive hamsters, respectively. RESULTS: The P. argentipes recombinant yellow-related protein PagSP04 showed high binding affinity to serotonin and low affinity to histamine. No binding activity was detected for two yellow-related proteins of S. schwetzi. Elevated concentrations of serotonin significantly reduced the amount of eggs laid by P. argentipes when compared to the control. The fecundity of S. schwetzi and the mortality of both sand fly species were not impaired after the experimental membrane feeding. Additionally, there were no differences in oviposition or mortality between P. argentipes females fed on immunized or naive hamsters. CONCLUSIONS: Our results suggest that in natural conditions sand flies are able to cope with biogenic amines or anti-saliva antibodies without any influence on their fitness. The serotonin binding by salivary yellow-related proteins may play an important role in Phlebotomus species feeding on mammalian hosts, but not in S. schwetzi, which is adapted to reptiles.

• Keywords
• Anti-saliva antibodies, Histamine, Mortality, Oviposition, Phlebotomus argentipes, Sergentomyia schwetzi, Serotonin, Yellow-related proteins,
• MeSH
• Biogenic Amines * blood   pharmacology   MeSH
• Fertility drug effects   MeSH
• Histamine blood   MeSH
• Insect Proteins chemistry   metabolism   MeSH
• Insect Bites and Stings immunology   MeSH
• Cricetinae MeSH
• Blood metabolism   MeSH
• Evolution, Molecular MeSH
• Mortality MeSH
• Phlebotomus metabolism   MeSH
• Reptiles MeSH
• Antibodies MeSH
• Psychodidae metabolism   MeSH
• Recombinant Proteins chemistry   metabolism   MeSH
• Mammals MeSH
• Serotonin blood   MeSH
• Salivary Proteins and Peptides * chemistry   metabolism   MeSH
• Saliva immunology   MeSH
• Protein Binding MeSH
• Animals MeSH
• Check Tag
• Cricetinae MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Biogenic Amines * MeSH
• Histamine MeSH
• Insect Proteins MeSH
• Antibodies MeSH
• Recombinant Proteins MeSH
• Serotonin MeSH
• Salivary Proteins and Peptides * MeSH

During the blood feeding, sand fly females inject saliva containing immunomodulatory and anti-haemostatic molecules into their vertebrate hosts. The saliva composition is species-specific, likely due to an adaptation to particular haemostatic pathways of their preferred host. Research on sand fly saliva is limited to the representatives of two best-studied genera, Phlebotomus and Lutzomyia. Although the members of the genus Sergentomyia are highly abundant in many areas in the Old World, their role in human disease transmission remains uncertain. Most Sergentomyia spp. preferentially attack various species of reptiles, but feeding on warm-blooded vertebrates, including humans and domestic animals, has been repeatedly described, especially for Sergentomyia schwetzi, of which salivary gland transcriptome and proteome is analyzed in the current study. Illumina RNA sequencing and de novo assembly of the reads and their annotation revealed 17,293 sequences homologous to other arthropods' proteins. In the sialome, all proteins typical for sand fly saliva were identified-antigen 5-related, lufaxin, yellow-related, PpSP15-like, D7-related, ParSP25-like, and silk proteins, as well as less frequent salivary proteins included 71kDa-like, ParSP80-like, SP16-like, and ParSP17-like proteins. Salivary enzymes include apyrase, hyaluronidase, endonuclease, amylase, lipase A2, adenosine deaminase, pyrophosphatase, 5'nucleotidase, and ribonuclease. Proteomics analysis of salivary glands identified 631 proteins, 81 of which are likely secreted into the saliva. We also compared two S. schwetzi lineages derived from the same origin. These lineages were adapted for over 40 generations for blood feeding either on mice (S-M) or geckos (S-G), two vertebrate hosts with different haemostatic mechanisms. Altogether, 20 and 40 annotated salivary transcripts were up-regulated in the S-M and S-G lineage, respectively. Proteomic comparison revealed ten salivary proteins more abundant in the lineage S-M, whereas 66 salivary proteins were enriched in the lineage S-G. No difference between lineages was found for apyrase activity; contrarily the hyaluronidase activity was significantly higher in the lineage feeding on mice.

• MeSH
• Apyrase analysis   genetics   metabolism   MeSH
• Phylogeny MeSH
• Insect Proteins analysis   genetics   metabolism   MeSH
• Hyaluronoglucosaminidase analysis   genetics   metabolism   MeSH
• Lizards MeSH
• Mice MeSH
• Psychodidae genetics   metabolism   MeSH
• Receptors, Odorant analysis   genetics   metabolism   MeSH
• Salivary Glands metabolism   MeSH
• Transcriptome * MeSH
• Animals MeSH
• Check Tag
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Apyrase MeSH
• Insect Proteins MeSH
• Hyaluronoglucosaminidase MeSH
• odorant-binding protein MeSH Browser
• Receptors, Odorant MeSH