Differential expression profiles of the salivary proteins SP15 and SP44 from Phlebotomus papatasi

Abstract

BackgroundSand fly saliva has been shown to help parasite establishment and to induce immune responses in vertebrate hosts. In the current study, we investigated the pattern of expression of two Phlebotomus papatasi salivary transcripts in specific physiological and seasonal conditions at a hyperendemic area of zoonotic cutaneous leishmaniasis (ZCL) in Iran.MethodsSand flies were collected during 2012–2013, and grouped according to physiological stages such as unfed, fed, semi-gravid, gravid, parous, nulliparous, infected or non-infected with Leishmania major and also based on the season in which they were collected. Quantitative Real-Time PCR was applied for assessment of the expression of two relevant salivary transcripts, PpSP15 and PpSP44, associated to protection from and exacerbation of ZCL, respectively.ResultsThe expression of PpSP15 and PpSP44 transcripts was significantly up-regulated (1.74 and 1.4 folds, respectively) in blood fed compared to unfed flies. Among four groups of fed, unfed, semi-gravid and gravid flies, the lowest levels of PpSP15 and PpSP44 expression were observed in gravid flies. Additionally, the expression levels of both PpSP15 and PpSP44 transcripts in P. papatasi collected during summer were significantly up-regulated (3.7 and 4.4 folds, respectively) compared to spring collections. In addition, the PpSP15 transcript exhibited a significant up-regulation (P < 0.05) in non-infected flies compared to those infected with L. major.ConclusionsThis study contributes to our knowledge of the differential expression of salivary genes among different groups within a P. papatasi population under natural field conditions. Cutaneous and visceral leishmaniasis are of public health importance in many parts of Iran and neighbouring countries where P. papatasi is the proven and dominant sand fly vector for ZCL, the most prevalent and endemic form of the disease in Iran. Therefore, the current study could be helpful in understanding the influence of salivary genes on Leishmania transmission by phlebotomine sand flies. Our findings demonstrate the differential expression of salivary transcripts under various physiological conditions potentially influencing the sand fly capacity for parasite transmission as well as the outcome of disease.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-016-1633-z) contains supplementary material, which is available to authorized users.

Species diversity and spatial distribution of CL/VL vectors: Evidence for variation in gene expression of immunogenic SP15 and LeIF proteins due to bioclimatic characteristics and physiological status of sand flies, Iran

“…Moreover, aging has been proved as another physiological factor affecting the gene expression profiles; however, it is not considered as significant as genotype or sex determination in insects [40]. Also, similar to what has been observed by other researchers [29], the direct relationship was corroborated between the up-regulation of SP15 transcript and aging.…”

“…Physiological status of sand flies was considered to determine SP15 gene expression level. Therefore, due to fresh-fed sand flies indicated a significant up-regulation of SP15 compared to un-fed ones [29], we selected only blood-fed sand flies to investigate the pattern of expression for SP15 transcript in different eco-epidemiologic conditions of Northern Khorasan province. After accomplishing definitive identification of female P. papatasi, salivary glands in addition to their head accessories were dissected using sterile forceps, and then were immediately resuspended in 50 μl of RNA-zole ® RT solution (MRC, OH, USA), homogenized, and stored at -20°C.…”

Epidemiological Survey of Cutaneous Leishmaniasis in Mazandaran Province, Northern Iran

“…Cutaneous leishmaniasis has been observed in 17 out of 31 provinces of Iran (11)(12)(13). The highest disease incidence has been reported in some provinces, such as Khorasan, Esfahan, Ilam, Fars, Yazd, Bushehr, Khuzestan, whereas western and northwest provinces of the country have been associated with the lowest incidence (14).…”

Sand fly saliva: toward a vaccine against leishmaniases

“…Another study which contributes to our knowledge of the differential expression of the salivary genes among different groups within a P. papatasi population has been conducted under natural field conditions in Iran. This study has reported the expression pattern of two P. papatasi salivary transcripts of PpSP15 and PpSP44 to be regulated by sand fly blood feeding, activity season, accessory gland status and leishmanial infection [58,59]. In laboratory examinations, immune responses to sand fly saliva have been detected in mice, hamsters, dogs and humans after multiple exposures to the bites or inoculation of dissected salivary glands from female P. papatasi, Phlebotomus argentipes, P. ariasi, P. sergenti, Lu.…”