The Influence of Sex and Fly Species on the Development of Trypanosomes in Tsetse Flies

Unlike other dipteran disease vectors, tsetse flies of both sexes feed on blood and transmit pathogenic African trypanosomes. During transmission, Trypanosoma brucei undergoes a complex cycle of proliferation and development inside the tsetse vector, culminating in production of infective forms in the saliva. The insect manifests robust immune defences throughout the alimentary tract, which eliminate many trypanosome infections. Previous work has shown that fly sex influences susceptibility to trypanosome infection as males show higher rates of salivary gland (SG) infection with T. brucei than females. To investigate sex-linked differences in the progression of infection, we compared midgut (MG), proventriculus, foregut and SG infections in male and female Glossina morsitans morsitans. Initially, infections developed in the same way in both sexes: no difference was observed in numbers of MG or proventriculus infections, or in the number and type of developmental forms produced. Female flies tended to produce foregut migratory forms later than males, but this had no detectable impact on the number of SG infections. The sex difference was not apparent until the final stage of SG invasion and colonisation, showing that the SG environment differs between male and female flies. Comparison of G. m. morsitans with G. pallidipes showed a similar, though less pronounced, sex difference in susceptibility, but additionally revealed very different levels of trypanosome resistance in the MG and SG. While G. pallidipes was more refractory to MG infection, a very high proportion of MG infections led to SG infection in both sexes. It appears that the two fly species use different strategies to block trypanosome infection: G. pallidipes heavily defends against initial establishment in the MG, while G. m. morsitans has additional measures to prevent trypanosomes colonising the SG, particularly in female flies. We conclude that the tsetse-trypanosome interface works differently in G. m. morsitans and G. pallidipes

E-cigarettes compromise the gut barrier and trigger inflammation.

E-cigarette usage continues to rise, yet the safety of e-cigarette aerosols is questioned. Using murine models of acute and chronic e-cigarette aerosol inhalation, murine colon transcriptomics, and murine and human gut-derived organoids in co-culture models, we assessed the effects of e-cigarette use on the gut barrier. Histologic and transcriptome analyses revealed that chronic, but not acute, nicotine-free e-cigarette use increased inflammation and reduced expression of tight junction (TJ) markers. Exposure of murine and human enteroid-derived monolayers (EDMs) to nicotine-free e-cigarette aerosols alone or in co-culture with bacteria also causes barrier disruption, downregulation of TJ protein, and enhanced inflammation in response to infection. These data highlight the harmful effects of "non-nicotine" component of e-cigarettes on the gut barrier. Considering the importance of an intact gut barrier for host fitness and the impact of gut mucosal inflammation on a multitude of chronic diseases, these findings are broadly relevant to both medicine and public health

The Hague, International City - UN City- City of Peace and International Justice: Onward to 2015!

E-cigarette usage continues to rise, yet the safety of e-cigarette aerosols is questioned. Using murine models of acute and chronic e-cigarette aerosol inhalation, murine colon transcriptomics, and murine and human gut-derived organoids in co-culture models, we assessed the effects of e-cigarette use on the gut barrier. Histologic and transcriptome analyses revealed that chronic, but not acute, nicotine-free e-cigarette use increased inflammation and reduced expression of tight junction (TJ) markers. Exposure of murine and human enteroid-derived monolayers (EDMs) to nicotine-free e-cigarette aerosols alone or in co-culture with bacteria also causes barrier disruption, downregulation of TJ protein, and enhanced inflammation in response to infection. These data highlight the harmful effects of "non-nicotine" component of e-cigarettes on the gut barrier. Considering the importance of an intact gut barrier for host fitness and the impact of gut mucosal inflammation on a multitude of chronic diseases, these findings are broadly relevant to both medicine and public health

E-cigarettes compromise the gut barrier and trigger gut inflammation

ABSTRACT: E-cigarette and vaping device use continue to rise, particularly in adolescents and young adults, but the safety of inhaling the multitude of chemicals within e-cigarette aerosols has been questioned. While several studies have evaluated vaping effects on the lungs and heart; effects on the gastrointestinal tract remain unknown. Using established murine models of acute (1 week) and chronic (3 month) daily e-cigarette aerosol inhalation, both with nicotine-containing and vehicle control e-liquids, murine colon transcriptomics and organoid co-culture models, we assessed the effects of e-cigarette use on the gut barrier and mucosal health. Histologic analyses revealed that chronic exposure to nicotine-free e-cigarette aerosols induced mucosal inflammation. Transcriptome analyses revealed that chronic, but not acute, nicotine-free e-cigarette use significantly reduced expression of tight junction markers, including occluding, and drove expression of pro-inflammatory cytokines. Exposure of murine and human enteroid-derived monolayers (EDMs) to nicotine-free e-cigarette aerosols alone, or in co-culture with invasiveE. coli,confirmed that repetitive exposure was sufficient to recapitulate the key findings observedin vivo, i.e., barrier-disruption, downregulation of occludin, inflammation, and an accentuated risk of and response to bacterial infection. These data highlight an unexpected harmful effect of e-cigarette use on the gut barrier and pinpoint non-nicotine chemical components common across >90% of e-cigarette e-liquids as the source of harm. Given the ever-expanding importance of the integrity of the gut barrier for host fitness, and impact of gut mucosal inflammation on a multitude of chronic diseases, these findings are broadly relevant to medicine and public health. SIGNIFICANCE: The safety of electronic cigarettes has been questioned amidst emerging evidence that they may derail our immune system and increase our susceptibility to infections. Despite these insights, their impact on the most critical entity that separates trillions of microbes from the largest immune system in our body, i.e., the gut barrier, remains unexplored. Using a combination of mouse models, gut transcriptomics, and murine and human gut-derived organoids, here we show that chronic exposure to aerosols of electronic-cigarette disrupts the gut barrier, increases its susceptibility to bacterial infections and triggers inflammation. Given the importance of the gut barrier in the maintenance of immune homeostasis, these findings provide valuable insights into the potential long-term harmful effects of electronic cigarettes on health

Metalloproteases in Trypanosoma rangeli-infected Rhodnius prolixus

Protease activities in the haemolymph and fat body in a bloodsucking insect, Rhodnius prolixus, infected with Trypanosoma rangeli, were investigated. After SDS-polyacrylamide gel electrophoresis containing gelatin as substrate, analysis of zymograms performed on samples of different tissues of controls and insects inoculated or orally infected with short or long epimastigotes of T. rangeli, demonstrated distinct patterns of protease activities: (i) proteases were detected in the haemolymph of insects which were fed on, or inoculated with, short epimastigotes of T. rangeli (39 kDa and 33 kDa, respectively), but they were not observed in the fat body taken from these insects; (ii) protease was also presented in the fat bodies derived from naive insects or controls inoculated with sterile phosphate-saline buffer (49 kDa), but it was not detected in the haemolymph of these insects; (iii) no protease activity was observed in both haemolymph and fat bodies taken from insects inoculated with, or fed on, long epimastigotes of T. rangeli. Furthermore, in short epimastigotes of T. rangeli extracts, three bands of the protease activities with apparent molecular weights of 297, 198 and 95 kDa were detected while long epimastigotes preparation presented only two bands of protease activities with molecular weights of 297 and 198 kDa. The proteases from the insect infected with T. rangeli and controls belong to the class of either metalloproteases or metal-activated enzymes since they are inhibited by 1,10-phenanthroline. The significance of these proteases in the insects infected with short epimastigotes of T. rangeli is discussed in relation to the success of the establishment of infection of these parasites in its vector, R. prolixus