Viral discovery and diversity in trypanosomatid protozoa with a focus on relatives of the human parasite <i>Leishmania</i>.

Knowledge of viral diversity is expanding greatly, but many lineages remain underexplored. We surveyed RNA viruses in 52 cultured monoxenous relatives of the human parasite &lt;i&gt;Leishmania&lt;/i&gt; ( &lt;i&gt;Crithidia&lt;/i&gt; and &lt;i&gt;Leptomonas&lt;/i&gt; ), as well as plant-infecting &lt;i&gt;Phytomonas&lt;/i&gt; &lt;i&gt;Leptomonas pyrrhocoris&lt;/i&gt; was a hotbed for viral discovery, carrying a virus (Leptomonas pyrrhocoris ostravirus 1) with a highly divergent RNA-dependent RNA polymerase missed by conventional BLAST searches, an emergent clade of tombus-like viruses, and an example of viral endogenization. A deep-branching clade of trypanosomatid narnaviruses was found, notable as &lt;i&gt;Leptomonas seymouri&lt;/i&gt; bearing Narna-like virus 1 (LepseyNLV1) have been reported in cultures recovered from patients with visceral leishmaniasis. A deep-branching trypanosomatid viral lineage showing strong affinities to bunyaviruses was termed " &lt;i&gt;Leishbunyavirus&lt;/i&gt; " (LBV) and judged sufficiently distinct to warrant assignment within a proposed family termed " &lt;i&gt;Leishbunyaviridae&lt;/i&gt; " Numerous relatives of trypanosomatid viruses were found in insect metatranscriptomic surveys, which likely arise from trypanosomatid microbiota. Despite extensive sampling we found no relatives of the totivirus &lt;i&gt;Leishmaniavirus&lt;/i&gt; (LRV1/2), implying that it was acquired at about the same time the &lt;i&gt;Leishmania&lt;/i&gt; became able to parasitize vertebrates. As viruses were found in over a quarter of isolates tested, many more are likely to be found in the &gt;600 unsurveyed trypanosomatid species. Viral loss was occasionally observed in culture, providing potentially isogenic virus-free lines enabling studies probing the biological role of trypanosomatid viruses. These data shed important insights on the emergence of viruses within an important trypanosomatid clade relevant to human disease

Exacerbated Leishmaniasis Caused by a Viral Endosymbiont can be Prevented by Immunization with Its Viral Capsid.

Recent studies have shown that a cytoplasmic virus called Leishmaniavirus (LRV) is present in some Leishmania species and acts as a potent innate immunogen, aggravating lesional inflammation and development in mice. In humans, the presence of LRV in Leishmania guyanensis and in L. braziliensis was significantly correlated with poor treatment response and symptomatic relapse. So far, no clinical effort has used LRV for prophylactic purposes. In this context, we designed an original vaccine strategy that targeted LRV nested in Leishmania parasites to prevent virus-related complications. To this end, C57BL/6 mice were immunized with a recombinant LRV1 Leishmania guyanensis viral capsid polypeptide formulated with a T helper 1-polarizing adjuvant. LRV1-vaccinated mice had significant reduction in lesion size and parasite load when subsequently challenged with LRV1+ Leishmania guyanensis parasites. The protection conferred by this immunization could be reproduced in naïve mice via T-cell transfer from vaccinated mice but not by serum transfer. The induction of LRV1 specific T cells secreting IFN-γ was confirmed in vaccinated mice and provided strong evidence that LRV1-specific protection arose via a cell mediated immune response against the LRV1 capsid. Our studies suggest that immunization with LRV1 capsid could be of a preventive benefit in mitigating the elevated pathology associated with LRV1 bearing Leishmania infections and possibly avoiding symptomatic relapses after an initial treatment. This novel anti-endosymbiotic vaccine strategy could be exploited to control other infectious diseases, as similar viral infections are largely prevalent across pathogenic pathogens and could consequently open new vaccine opportunities

Chops and Trademarks: Asian Trading Ports and Textile Branding, 1840-1920

This article is a contribution to the prehistory of modern branding, presenting a case study of the textile trade in colonial Southeast Asia. The visual appearance of brands as well as their social meaning were altered in the cultural encounter of colonial trade. Through these encounters, trademarks were modernized: the reputation of a producer became less important than the distinctiveness of the produc

FOXC2 and fluid shear stress stabilize postnatal lymphatic vasculature.

Biomechanical forces, such as fluid shear stress, govern multiple aspects of endothelial cell biology. In blood vessels, disturbed flow is associated with vascular diseases, such as atherosclerosis, and promotes endothelial cell proliferation and apoptosis. Here, we identified an important role for disturbed flow in lymphatic vessels, in which it cooperates with the transcription factor FOXC2 to ensure lifelong stability of the lymphatic vasculature. In cultured lymphatic endothelial cells, FOXC2 inactivation conferred abnormal shear stress sensing, promoting junction disassembly and entry into the cell cycle. Loss of FOXC2-dependent quiescence was mediated by the Hippo pathway transcriptional coactivator TAZ and, ultimately, led to cell death. In murine models, inducible deletion of Foxc2 within the lymphatic vasculature led to cell-cell junction defects, regression of valves, and focal vascular lumen collapse, which triggered generalized lymphatic vascular dysfunction and lethality. Together, our work describes a fundamental mechanism by which FOXC2 and oscillatory shear stress maintain lymphatic endothelial cell quiescence through intercellular junction and cytoskeleton stabilization and provides an essential link between biomechanical forces and endothelial cell identity that is necessary for postnatal vessel homeostasis. As FOXC2 is mutated in lymphedema-distichiasis syndrome, our data also underscore the role of impaired mechanotransduction in the pathology of this hereditary human disease

RIP4 inhibits STAT3 signaling to sustain lung adenocarcinoma differentiation.

Loss of epithelial differentiation and extracellular matrix (ECM) remodeling are known to facilitate cancer progression and are associated with poor prognosis in patients with lung cancer. We have identified Receptor-interacting serine/threonine protein kinase 4 (RIP4) as a regulator of tumor differentiation in lung adenocarcinoma (AC). Bioinformatics analyses of human lung AC samples showed that poorly differentiated tumors express low levels of RIP4, whereas high levels are associated with better overall survival. In vitro, lung tumor cells expressing reduced RIP4 levels showed enhanced activation of STAT3 signaling and had a greater ability to invade through collagen. In contrast, overexpression of RIP4 inhibited STAT3 activation, which abrogated interleukin-6-dependent induction of lysyl oxidase, a collagen cross-linking enzyme. In an autochthonous mouse model of lung AC initiated by Kras(G12D) expression with loss of p53, Rip4 knockdown tumors progressed to a poorly differentiated state marked by an increase in Hmga2, reduced Ttf1, and enrichment of genes regulating extracellular remodeling and Jak-Stat signaling. Tail vein injections of cells overexpressing Rip4 showed a reduced potential to invade and form tumors, which was restored by co-expression of Stat3. Altogether, our work has identified that loss of RIP4 enhances STAT3 signaling in lung cancer cells, promoting the expression of ECM remodeling genes and cancer dedifferentiation

Apoptosis-like cell death in Leishmania donovani treated with KalsomeTM10, a new liposomal amphotericin B

The present study aimed to elucidate the cell death mechanism in Leishmania donovani upon treatment with KalsomeTM10, a new liposomal amphotericin B. Methodology/Principal findings We studied morphological alterations in promastigotes through phase contrast and scanning electron microscopy. Phosphatidylserine (PS) exposure, loss of mitochondrial membrane potential and disruption of mitochondrial integrity was determined by flow cytometry using annexinV-FITC, JC-1 and mitotraker, respectively. For analysing oxidative stress, generation of H2O2 (bioluminescence kit) and mitochondrial superoxide O2 − (mitosox) were measured. DNA fragmentation was evaluated using terminal deoxyribonucleotidyl transferase mediated dUTP nick-end labelling (TUNEL) and DNA laddering assay. We found that KalsomeTM10 is more effective then Ambisome against the promastigote as well as intracellular amastigote forms. The mechanistic study showed that KalsomeTM10 induced several morphological alterations in promastigotes typical of apoptosis. KalsomeTM10 treatment showed a dose- and time-dependent exposure of PS in promastigotes. Further,study on mitochondrial pathway revealed loss of mitochondrial membrane potential as well as disruption in mitochondrial integrity with depletion of intracellular pool of ATP. KalsomeTM10 treated promastigotes showed increased ROS production, diminished GSH levels and increased caspase-like activity. DNA fragmentation and cell cycle arrest was observed in KalsomeTM10 treated promastigotes. Apoptotic DNA fragmentation was also observed in KalsomeTM10 treated intracellular amastigotes. KalsomeTM10 induced generation of ROS and nitric oxide leads to the killing of the intracellular parasites. Moreover, endocytosis is indispensable for KalsomeTM10 mediated anti-leishmanial effect in host macrophag

Modulation of the peripheral blood transcriptome by the ingestion of probiotic yoghurt and acidified milk in healthy, young men

The metabolic health benefits of fermented milks have already been investigated using clinical biomarkers but the development of transcriptomic analytics in blood offers an alternative approach that may help to sensitively characterise such effects. We aimed to assess the effects of probiotic yoghurt intake, compared to non-fermented, acidified milk intake, on clinical biomarkers and gene expression in peripheral blood. To this end, a randomised, crossover study was conducted in fourteen healthy, young men to test the two dairy products. For a subset of seven subjects, RNA sequencing was used to measure gene expression in blood collected during postprandial tests and after two weeks daily intake. We found that the postprandial response in insulin was different for probiotic yoghurt as compared to that of acidified milk. Moreover changes in several clinical biomarkers were associated with changes in the expression of genes representing six metabolic genesets. Assessment of the postprandial effects of each dairy product on gene expression by geneset enrichment analysis revealed significant, similar modulation of inflammatory and glycolytic genes after both probiotic yoghurt and acidified milk intake, although distinct kinetic characteristics of the modulation differentiated the dairy products. The aryl hydrocarbon receptor was a major contributor to the down-regulation of the inflammatory genesets and was also positively associated with changes in circulating insulin at 2h after yoghurt intake (p = 0.05). Daily intake of the dairy products showed little effect on the fasting blood transcriptome. Probiotic yoghurt and acidified milk appear to affect similar gene pathways during the postprandial phase but differences in the timing and the extent of this modulation may lead to different physiological consequences. The functional relevance of these differences in gene expression is supported by their associations with circulating biomarkers

AMPK in Pathogens

During host–pathogen interactions, a complex web of events is crucial for the outcome of infection. Pathogen recognition triggers powerful cellular signaling events that is translated into the induction and maintenance of innate and adaptive host immunity against infection. In opposition, pathogens employ active mechanisms to manipulate host cell regulatory pathways toward their proliferation and survival. Among these, subversion of host cell energy metabolism by pathogens is currently recognized to play an important role in microbial growth and persistence. Extensive studies have documented the role of AMP-activated protein kinase (AMPK) signaling, a central cellular hub involved in the regulation of energy homeostasis, in host–pathogen interactions. Here, we highlight the most recent advances detailing how pathogens hijack cellular metabolism by suppressing or increasing the activity of the host energy sensor AMPK. We also address the role of lower eukaryote AMPK orthologues in the adaptive process to the host microenvironment and their contribution for pathogen survival, differentiation, and growth. Finally, we review the effects of pharmacological or genetic AMPK modulation on pathogen growth and persistence.CIHR -Canadian Institutes of Health Researc

Cathepsin B-like and cell death in the unicellular human pathogen Leishmania

In several studies reporting cell death (CD) in lower eukaryotes and in the human protozoan parasite Leishmania, proteolytic activity was revealed using pan-caspase substrates or inhibitors such as carbobenzoxy-valyl-alanyl-aspartyl-[O-methyl]-fluoromethylketone (Z-VAD-FMK). However, most of the lower eukaryotes do not encode caspase(s) but MCA, which differs from caspase(s) in its substrate specificity and cannot be accountable for the recognition of Z-VAD-FMK. In the present study, we were interested in identifying which enzyme was capturing the Z-VAD substrate. We show that heat shock (HS) induces Leishmania CD and leads to the intracellular binding of Z-VAD-FMK. We excluded binding and inhibition of Z-VAD-FMK to Leishmania major metacaspase (LmjMCA), and identified cysteine proteinase C (LmjCPC), a cathepsin B-like (CPC) enzyme, as the Z-VAD-FMK binding enzyme. We confirmed the specific interaction of Z-VAD-FMK with CPC by showing that Z-VAD binding is absent in a Leishmania mexicana strain in which the cpc gene was deleted. We also show that parasites exposed to various stress conditions release CPC into a soluble fraction. Finally, we confirmed the role of CPC in Leishmania CD by showing that, when exposed to the oxidizing agent hydrogen peroxide (H2O2), cpc knockout parasites survived better than wild-type parasites (WT). In conclusion, this study identified CPC as the substrate of Z-VAD-FMK in Leishmania and as a potential additional executioner protease in the CD cascade of Leishmania and possibly in other lower eukaryotes

Role of apoptosis-inducing factor (AIF) in programmed nuclear death during conjugation in Tetrahymena thermophila

<p>Abstract</p> <p>Background</p> <p>Programmed nuclear death (PND), which is also referred to as nuclear apoptosis, is a remarkable process that occurs in ciliates during sexual reproduction (conjugation). In <it>Tetrahymena thermophila</it>, when the new macronucleus differentiates, the parental macronucleus is selectively eliminated from the cytoplasm of the progeny, concomitant with apoptotic nuclear events. However, the molecular mechanisms underlying these events are not well understood. The parental macronucleus is engulfed by a large autophagosome, which contains numerous mitochondria that have lost their membrane potential. In animals, mitochondrial depolarization precedes apoptotic cell death, which involves DNA fragmentation and subsequent nuclear degradation.</p> <p>Results</p> <p>We focused on the role of mitochondrial apoptosis-inducing factor (AIF) during PND in <it>Tetrahymena</it>. The disruption of <it>AIF </it>delays the normal progression of PND, specifically, nuclear condensation and kilobase-size DNA fragmentation. AIF is localized in <it>Tetrahymena </it>mitochondria and is released into the macronucleus prior to nuclear condensation. In addition, AIF associates and co-operates with the mitochondrial DNase to facilitate the degradation of kilobase-size DNA, which is followed by oligonucleosome-size DNA laddering.</p> <p>Conclusions</p> <p>Our results suggest that <it>Tetrahymena </it>AIF plays an important role in the degradation of DNA at an early stage of PND, which supports the notion that the mitochondrion-initiated apoptotic DNA degradation pathway is widely conserved among eukaryotes.</p