scholarly journals Leishmania infection induces a limited differential gene expression in the sand fly midgut

2020 ◽  
Author(s):  
Iliano V. Coutinho-Abreu ◽  
Tiago D. Serafim ◽  
Claudio Meneses ◽  
Shaden Kamhawi ◽  
Fabiano Oliveira ◽  
...  

Abstract Background: Sand flies are the vectors of Leishmania parasites. To develop in the sand fly midgut, Leishmania multiplies and undergoes various stage differentiations giving rise to the infective form, the metacyclic promastigotes. To determine the changes in sand fly midgut gene expression caused by the presence of Leishmania, we performed RNA-Seq of uninfected and Leishmania infantum-infected Lutzomyia longipalpis midguts from seven different libraries corresponding to time points which cover the various Leishmania developmental stages. Results: The combined transcriptomes resulted in the de novo assembly of 13,841 sand fly midgut transcripts. Importantly, only 113 sand fly transcripts, about 1%, were differentially expressed in the presence of Leishmania parasites. Further, we observed distinct differentially expressed sand fly midgut transcripts corresponding to the presence of each of the various Leishmania stages suggesting that each parasite stage influences midgut gene expression in a specific manner. Two main patterns of sand fly gene expression modulation were noted. At early time points (days 1-4), more transcripts were down-regulated by Leishmania infection at large fold changes (> 32 fold). Among the down-regulated genes, the transcription factor Forkhead/HNF-3 and hormone degradation enzymes were differentially regulated on day 2 and appear to be the upstream regulators of nutrient transport, digestive enzymes, and peritrophic matrix proteins. Conversely, at later time points (days 6 onwards), most of the differentially expressed transcripts were up-regulated by Leishmania infection with small fold changes (< 32 fold). The molecular functions of these genes have been associated with the metabolism of lipids and detoxification of xenobiotics. Conclusion: Overall, our data suggest that the presence of Leishmania produces a limited change in the midgut transcript expression profile in sand flies. Further, Leishmania modulates sand fly gene expression early on in the developmental cycle in order to overcome the barriers imposed by the midgut, yet it behaves like a commensal at later time points where a massive number of parasites in the anterior midgut results only in modest changes in midgut gene expression.

2020 ◽  
Author(s):  
Iliano V. Coutinho-Abreu ◽  
Tiago D. Serafim ◽  
Claudio Meneses ◽  
Shaden Kamhawi ◽  
Fabiano Oliveira ◽  
...  

Abstract Background: Sand flies are the vectors of Leishmania parasites. To develop in the sand fly midgut, Leishmania multiplies and undergoes various stage differentiations giving rise to the infective form, the metacyclic promastigotes. To determine the changes in sand fly midgut gene expression caused by the presence of Leishmania, we performed RNA-Seq of uninfected and Leishmania infantum-infected Lutzomyia longipalpis midguts from seven different libraries corresponding to time points which cover the various Leishmania developmental stages. Results: The combined transcriptomes resulted in the de novo assembly of 13,841 sand fly midgut transcripts. Importantly, only 113 sand fly transcripts, about 1%, were differentially expressed in the presence of Leishmania parasites. Further, we observed distinct differentially expressed sand fly midgut transcripts corresponding to the presence of each of the various Leishmania stages suggesting that each parasite stage influences midgut gene expression in a specific manner. Two main patterns of sand fly gene expression modulation were noted. At early time points (days 1-4), more transcripts were down-regulated by Leishmania infection at large fold changes (> 32 fold). Among the down-regulated genes, the transcription factor Forkhead/HNF-3 and hormone degradation enzymes were differentially regulated on day 2 and appear to be the upstream regulators of nutrient transport, digestive enzymes, and peritrophic matrix proteins. Conversely, at later time points (days 6 onwards), most of the differentially expressed transcripts were up-regulated by Leishmania infection with small fold changes (< 32 fold). The molecular functions of these genes have been associated with the metabolism of lipids and detoxification of xenobiotics. Conclusion: Overall, our data suggest that the presence of Leishmania produces a limited change in the midgut transcript expression profile in sand flies. Further, Leishmania modulates sand fly gene expression early on in the developmental cycle in order to overcome the barriers imposed by the midgut, yet it behaves like a commensal at later time points where a massive number of parasites in the anterior midgut results only in modest changes in midgut gene expression.


2020 ◽  
Author(s):  
Iliano V. Coutinho-Abreu ◽  
Tiago D. Serafim ◽  
Claudio Meneses ◽  
Shaden Kamhawi ◽  
Fabiano Oliveira ◽  
...  

Abstract Background: Phlebotomine sand flies are the vectors of Leishmania worldwide. To develop in the sand fly midgut, Leishmania multiplies and undergoes multiple stage differentiations leading to the infective form, the metacyclic promastigotes. To gain a better understanding of the influence of Leishmania infection on midgut gene expression, we performed RNA-Seq comparing uninfected and Leishmania infantum -infected Lutzomyia longipalpis midguts at seven time points which cover the various Leishmania developmental stages including early time points when blood digestion is taking place, and late time points when the parasites are undergoing metacyclogenesis. Results: Out of over 13,841 transcripts assembled de novo , only 113 sand fly transcripts, about 1%, were differentially expressed. Further, we observed a low overlap of differentially expressed sand fly transcripts across different time points suggesting that each Leishmania stage influences midgut gene expression in a specific manner. Two main patterns of sand fly gene expression modulation were noted. At early time points (days 1-4), more transcripts were down-regulated by Leishmania infection at large fold changes (> -32 fold). Among the down-regulated genes, the transcription factor Forkhead/HNF-3 and hormone degradation enzymes were differentially regulated on day 4 and appear to be the upstream regulators of nutrient transport, digestive enzymes, and peritrophic matrix proteins. Conversely, at later time points (days 6 onwards), most of the differentially expressed transcripts were up-regulated by small fold changes (< 32 fold). The molecular function of these genes has been associated with the metabolism of lipids and detoxification of xenobiotics. Conclusion: Overall, it appears that Leishmania modulates sand fly gene expression early on in order to overcome the barriers imposed by the midgut, yet it behaves like a commensal at later time points, where a massive number of parasites in the anterior midgut results only in modest changes in midgut gene expression.


2019 ◽  
Author(s):  
Iliano V. Coutinho-Abreu ◽  
Tiago D. Serafim ◽  
Claudio Meneses ◽  
Shaden Kamhawi ◽  
Fabiano Oliveira ◽  
...  

Abstract Background: Phlebotomine sand flies are the vectors of Leishmania worldwide. To develop in the sand fly midgut, Leishmania multiplies and undergoes multiple stage differentiations leading to the infective form, the metacyclic promastigotes. To gain a better understanding of the influence of Leishmania infection in midgut gene expression, we performed RNA-Seq comparing uninfected Lutzomyia longipalpis midguts and Leishmania infantum-infected Lutzomyia longipalpis midguts at seven time points which cover the various developmental Leishmania stages including early time points when blood digestion is taking place and late time points when the parasites are undergoing metacyclogenesis. Results: Out of over 13,841 transcripts assembled de novo, only 113 sand fly transcripts, about 1%, were differentially expressed. Further, we observed a low overlap of differentially expressed sand fly transcripts across different time points suggesting a specific influence of each Leishmania stage on midgut gene expression. Two main patterns of sand fly gene expression modulation were noticed. At early time points (days 1-4), more transcripts were down-regulated by Leishmania infection at large fold changes (> -32 fold). Among the down-regulated genes, the transcription factor Forkhead/HNF-3 and hormone degradation enzymes were differentially regulated on day 4 and appear to be the upstream regulators of nutrient transport, digestive enzymes, and peritrophic matrix proteins. Conversely, at later time points (days 6 onwards), most of the differentially expressed transcripts were up-regulated by small fold changes (< 32 fold), and the molecular function of such genes are associated with the metabolism of lipids and detoxification of xenobiotics (P450). Conclusion: Overall, it appears that Leishmania modulates sand fly gene expression early on in order to overcome the barriers imposed by the midgut, yet it behaves like a commensal at later time points, when modest midgut gene expression changes correlate with a massive amount of parasites in the anterior midgut.


2019 ◽  
Author(s):  
Iliano V. Coutinho-Abreu ◽  
Tiago D. Serafim ◽  
Claudio Meneses ◽  
Shaden Kamhawi ◽  
Fabiano Oliveira ◽  
...  

AbstractBackgroundPhlebotomine sand flies are the vectors of Leishmania worldwide. To develop in the sand fly midgut, Leishmania multiplies and undergoes multiple stage differentiations leading to the infective form, the metacyclic promastigotes. To gain a better understanding of the influence of Leishmania infection in midgut gene expression, we performed RNA-Seq comparing uninfected Lutzomyia longipalpis midguts and Leishmania infantum-infected Lutzomyia longipalpis midguts at seven time points which cover the various developmental Leishmania stages including early time points when blood digestion is taking place and late time points when the parasites are undergoing metacyclogenesis.ResultsOut of over 13,841 transcripts assembled de novo, only 113 sand fly transcripts, about 1%, were differentially expressed. Further, we observed a low overlap of differentially expressed sand fly transcripts across different time points suggesting a specific influence of each Leishmania stage on midgut gene expression. Two main patterns of sand fly gene expression modulation were noticed. At early time points (days 1-4), more transcripts were down-regulated by Leishmania infection at large fold changes (> −32 fold). Among the down-regulated genes, the transcription factor Forkhead/HNF-3 and hormone degradation enzymes were differentially regulated on day 4 and appear to be the upstream regulators of nutrient transport, digestive enzymes, and peritrophic matrix proteins. Conversely, at later time points (days 6 onwards), most of the differentially expressed transcripts were up-regulated by small fold changes (< 32 fold), and the molecular function of such genes are associated with the metabolism of lipids and detoxification of xenobiotics (P450).ConclusionOverall, it appears that Leishmania modulates sand fly gene expression early on in order to overcome the barriers imposed by the midgut, yet it behaves like a commensal at later time points, when modest midgut gene expression changes correlate with a massive amount of parasites in the anterior midgut.


2019 ◽  
Vol 56 (5) ◽  
pp. 1368-1376 ◽  
Author(s):  
Josiane V Lopes ◽  
Erika M Michalsky ◽  
Nathalia C L Pereira ◽  
Adão J V de Paula ◽  
Fabiana O Lara-Silva ◽  
...  

Abstract Among neglected tropical diseases, visceral leishmaniasis (VL) shows great relevance in global terms and is a serious public health concern due to the possibility of severe and lethal forms in humans. In this study, we evaluate entomological factors such as diversity and abundance of phlebotomine sand flies (Diptera:Psychodidae) and the Leishmania species circulating in these species in possible association with VL transmission in the Brazilian town Itaúna. The entomological collections were performed during three consecutive nights, always in the third week of each month, within a period of 12 mo. A total of 1,786 sand fly specimens were collected, from which 20% were collected inside houses. The influence of three local climatic variables (temperature, rainfall, relative humidity) on the population sizes of these insects was evaluated. Temperature was the most influential factor, with a significant positive correlation with the local population size of phlebotomine sand flies collected per month. Lutzomyia longipalpis (Lutz & Neiva, 1912) was the predominant species in the study area. Leishmania DNA was detected in nine out of 133 pools of sand fly females, using nested/PCR, which resulted in a minimal natural infection rate of 2.91%. DNA from Leishmania infantum Nicolle, 1908 (Kinetoplastida: Trypanosomatida), was detected in Evandromyia cortelezzii (Bréthes, 1923), Ev. evandroi (Costa, Lima & Antunes, 1936), Ev. lenti (Mangabeira, 1938), and Ev. termitophila (Martins, Falcão & Silva, 1964), besides Lu. longipalpis. Our study indicates favorable conditions for VL spreading in Itaúna due to the presence of Lu. longipalpis and Le. infantum-infected phlebotomine sand flies.


2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
C. S. Moraes ◽  
K. Aguiar-Martins ◽  
S. G. Costa ◽  
P. A. Bates ◽  
R. J. Dillon ◽  
...  

Lutzomyia longipalpis is the main vector of visceral leishmaniasis (VL) in America. Physiological and molecular mechanisms of Leishmania infection in sand flies have been studied during the first gonotrophic cycle. There are few studies about these interactions during the second gonotrophic cycle mainly because of the difficulties maintaining sand flies through sequential feeds. Here we standardized conditions to perform the second blood feed efficiently, and our results show that oviposition is an essential factor for the success of multiple feeds. We evaluated the impact of the second blood meal on longevity, protein digestion, trypsin activity, and Leishmania mexicana development within L. longipalpis gut. Mortality of blood-fed females increases after second blood meal as compared to sugar-fed females. Trypsin activity was lower during the second gonotrophic cycle. However, no difference in protein intake was observed between blood meals. There was no difference in the population size of Leishmania in the gut after both blood meals. In this work, we presented an optimized protocol for obtaining sufficient numbers of sand fly females fed on a second blood meal, and we described some physiological and parasitological aspects of the second gonotrophic cycle which might influence the vectorial competence of sand flies.


Author(s):  
Camila Oliveira Vasconcelos ◽  
Zirlane C. Branco Coelho ◽  
Cristina de Souza Chaves ◽  
Clarissa Romero Teixeira ◽  
Margarida M. Lima Pompeu ◽  
...  

Recruitment of a specific cell population after Leishmania infection can influence the outcome of the disease. Cellular migration in response to Leishmania or vector saliva has been reported in air pouch model, however, cellular migration induced by Leishmania associated with host's blood and vector saliva in this model has not been described. Herein we investigated cellular migration into air pouch of hamster after stimulation with combination of L. chagasi and host's blood and Lutzomyia longipalpis saliva. Migration induced by saliva was 3-fold more than those induced by L. chagasi alone. Additionally, L. chagasi associated with blood and saliva induced significantly even more leukocytes into air pouch than Leishmania alone. L. chagasi recruited a diverse cell population; however, most of these cells seem to have not migrated to the inflammatory exudate, remaining in the pouch lining tissue. These results indicate that L. chagasi can reduce leukocyte accumulation to the initial site of infection, and when associated with vector saliva in the presence of blood components, increase the influx of more neutrophils than macrophages, suggesting that the parasite has developed a strategy to minimize the initial inflammatory response, allowing an unlimited progression within the host. This work reinforces the importance of studies on the salivary components of sand fly vectors of leishmaniasis in the transmission process and the establishment of the infection.


2021 ◽  
Vol 17 (3) ◽  
pp. e1009354
Author(s):  
Monica E. Staniek ◽  
James G. C. Hamilton

Globally visceral leishmaniasis (VL) causes thousands of human deaths every year. In South America, the etiologic agent, Leishmania infantum, is transmitted from an infected canine reservoir to human hosts by the bite of the sand fly vector; predominantly Lutzomyia longipalpis. Previous evidence from model rodent systems have suggested that the odour of infected hosts is altered by the parasite making them more attractive to the vector leading to an increased biting rate and improved transmission prospects for the pathogen. However, there has been no assessment of the effect of Le infantum infection on the attractiveness of dogs, which are the natural reservoirs for human infection. Hair collected from infected and uninfected dogs residing in a VL endemic city in Brazil was entrained to collect the volatile chemical odours present in the headspace. Female and male Lu. longipalpis sand flies were offered a choice of odour entrained from infected and uninfected dogs in a series of behavioural experiments. Odour of uninfected dogs was equally attractive to male or female Lu. longipalpis when compared to a solvent control. Female Lu. longipalpis were significantly more attracted to infected dog odour than uninfected dog odour in all 15 experimental replicates (average 45.7±0.87 females attracted to infected odour; 23.9±0.82 to uninfected odour; paired T-test, P = 0.000). Male Lu. longipalpis did not significantly prefer either infected or uninfected odour (average 36.1±0.4 males to infected odour; 35.7±0.6 to uninfected odour; paired T-test, P = 0.722). A significantly greater proportion of females chose the infected dog odour compared to the males (paired T-test, P = 0.000). The results showed that the odour of dogs infected with Le. infantum was significantly more attractive to blood-seeking female sand flies than it was to male sand flies. This is strong evidence for parasite manipulation of the host odour in a natural transmission system and indicates that infected dogs may have a disproportionate significance in maintaining infection in the canine and human population.


2021 ◽  
Vol 2 ◽  
Author(s):  
Erich Loza Telleria ◽  
Daisy Aline Azevedo-Brito ◽  
Barbora Kykalová ◽  
Bruno Tinoco-Nunes ◽  
André Nóbrega Pitaluga ◽  
...  

Phlebotomine sand flies (Diptera, Psychodidae) belonging to the Lutzomyia genus transmit zoonoses in the New World. Lutzomyia longipalpis is the main vector of Leishmania infantum, which is the causative agent of visceral leishmaniasis in Brazil. To identify key molecular aspects involved in the interaction between vector and pathogens and contribute to developing disease transmission controls, we investigated the sand fly innate immunity mediated by the Janus kinase/signal transducer and activator of transcription (Jak-STAT) pathway in response to L. infantum infection. We used two study models: L. longipalpis LL5 embryonic cells co-cultured with L. infantum and sand fly females artificially infected with the parasite. We used qPCR to follow the L. longipalpis gene expression of molecules involved in the Jak-STAT pathway. Also, we modulated the Jak-STAT mediated immune response to understand its role in Leishmania parasite infection. For that, we used RNAi to silence the pathway regulators, protein inhibitor of activated STATs (PIAS) in LL5 cells, and STAT in adult females. In addition, the pathway suppression effect on parasite development within the vector was assessed by light microscopy in late-phase infection. The silencing of the repressor PIAS in LL5 cells led to a moderate increase in a protein tyrosine phosphatase 61F (PTP61F) expression. It suggests a compensatory regulation between these two repressors. L. infantum co-culture with LL5 cells upregulated repressors PIAS, suppressor of cytokine signaling (SOCS), and PTP61F. It also downmodulated virus-induced RNA-1 (VIR-1), a pathway effector, indicating that the parasite could repress the Jak-STAT pathway in LL5 cells. In Leishmania-infected L. longipalpis females, STAT and the antimicrobial peptide attacin were downregulated on the third day post-infection, suggesting a correlation that favors the parasite survival at the end of blood digestion in the sand fly. The antibiotic treatment of infected females showed that the reduction of gut bacteria had little effect on the Jak-STAT pathway regulation. STAT gene silencing mediated by RNAi reduced the expression of inducible nitric oxide synthase (iNOS) and favored Leishmania growth in sand flies on the first day post-infection. These results indicate that STAT participated in the iNOS regulation with subsequent effect on parasite survival.


BMC Genomics ◽  
2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Iliano V. Coutinho-Abreu ◽  
Tiago Donatelli Serafim ◽  
Claudio Meneses ◽  
Shaden Kamhawi ◽  
Fabiano Oliveira ◽  
...  

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