ATG9A regulates the dissociation of recycling endosomes from microtubules to form liquid influenza A virus inclusions

It is now established that many viruses that threaten public health establish condensates via phase transitions to complete their lifecycles, and knowledge on such processes may offer new strategies for antiviral therapy. In the case of influenza A virus (IAV), liquid condensates known as viral inclusions, concentrate the 8 distinct viral ribonucleoproteins (vRNPs) that form IAV genome and are viewed as sites dedicated to the assembly of the 8-partite genomic complex. Despite not being delimited by host membranes, IAV liquid inclusions accumulate host membranes inside as a result of vRNP binding to the recycling endocytic marker Rab11a, a driver of the biogenesis of these structures. We lack molecular understanding on how Rab11a-recycling endosomes condensate specifically near the endoplasmic reticulum (ER) exit sites upon IAV infection. We show here that liquid viral inclusions interact with the ER to fuse, divide, and slide. We uncover that, contrary to previous indications, the reported reduction in recycling endocytic activity is a regulated process rather than a competition for cellular resources involving a novel role for the host factor ATG9A. In infection, ATG9A mediates the removal of Rab11a-recycling endosomes carrying vRNPs from microtubules. We observe that the recycling endocytic usage of microtubules is rescued when ATG9A is depleted, which prevents condensation of Rab11a endosomes near the ER. The failure to produce viral inclusions accumulates vRNPs in the cytosol and reduces genome assembly and the release of infectious virions. We propose that the ER supports the dynamics of liquid IAV inclusions, with ATG9A facilitating their formation. This work advances our understanding on how epidemic and pandemic influenza genomes are formed. It also reveals the plasticity of recycling endosomes to undergo condensation in response to infection, disclosing new roles for ATG9A beyond its classical involvement in autophagy.

Sexual dimorphism in Kinosternon scorpioides (Linnaeus, 1766) from the Brazilian Amazon

The sexual dimorphism of the Kinosternon scorpioides was evaluated using two different techniques (linear and geometric morphometry) from images and linear measurements of the carapace and plastron of adults (male and female). Linear morphometry indicated that the height and width of carapace and plastron are statistically different between sexes, with females being wider and taller. In the evaluation of geometric morphometry, ANOVA demonstrated variation in the size of the plastron and the shape of the carapace and plastron, expressing a tendency in shape for each sex. Sexual dimorphism, therefore, is verified for this species, notably by the plastron. This study indicates an additional tool for the phenotypic knowledge of animals, contributing to the study of threatened populations.

The 3D architecture and molecular foundations of de novo centriole assembly via bicentrioles

Centrioles are structurally conserved organelles, composing both centrosomes and cilia. In animal cycling cells, centrioles often form through a highly characterized process termed canonical duplication. However, a large diversity of eukaryotes assemble centrioles de novo through uncharacterized pathways. This unexplored diversity is key to understanding centriole assembly mechanisms and how they evolved to assist specific cellular functions. Here, we show that, during spermatogenesis of the bryophyte Physcomitrium patens, centrioles are born as a co-axially oriented centriole pair united by a cartwheel. Interestingly, we observe that these centrioles are twisted in opposite orientations. Microtubules emanate from the bicentrioles, which localize to the spindle poles during cell division. After their separation, the two resulting sister centrioles mature asymmetrically, elongating specific microtubule triplets and a naked cartwheel. Subsequently, two motile cilia are assembled that appear to alternate between different motility patterns. We further show that centriolar components SAS6, Bld10, and POC1, which are conserved across eukaryotes, are expressed during spermatogenesis and required for this de novo biogenesis pathway. Our work supports a scenario where centriole biogenesis, while driven by conserved molecular modules, is more diverse than previously thought.

The 3D architecture and molecular foundations of de novo centriole assembly via bicentrioles

Centrioles are structurally conserved organelles, composing both centrosomes and cilia. In animal cycling cells, centrioles often form through a highly characterized process termed canonical duplication. However, a large diversity of eukaryotes assemble centrioles de novo through uncharacterized pathways. This unexplored diversity is key to understanding centriole assembly mechanisms and how they evolved to assist specific cellular functions. Here, we show that, during spermatogenesis of the bryophyte Physcomitrium patens, centrioles are born as a co-axially oriented centriole pair united by a cartwheel. Interestingly, we observe that these centrioles are twisted in opposite orientations. Microtubules emanate from the bicentrioles, which localize to the spindle poles during cell division. After their separation, the two resulting sister centrioles mature asymmetrically, elongating specific microtubule triplets and a naked cartwheel. Subsequently, two motile cilia are assembled that appear to alternate between different motility patterns. We further show that centriolar components SAS6, Bld10, and POC1, which are conserved across eukaryotes, are expressed during spermatogenesis and required for this de novo biogenesis pathway. Our work supports a scenario where centriole biogenesis, while driven by conserved molecular modules, is more diverse than previously thought.

The Histo-CLEM Workflow for tissues of model organisms

Bridging from the macrostructure to the nanostructure of tissues is often technically challenging. To try to solve this, we developed a flexible CLEM workflow that can be applied to the analysis of tissues from diverse model organisms across various length scales. The Histo-CLEM Workflow combines three main microscopy techniques, namely histology, light microscopy and electron microscopy. Herein, all the steps of the Histo-CLEM Workflow are explained in detail to enable the adaptation of the method to tissue particularities and biological questions. The preparation and visualization of mice nerve fibers is shown as an application example of the presented Histo-CLEM Workflow.

Is the Proteome of Bronchoalveolar Lavage Extracellular Vesicles a Marker of Advanced Lung Cancer?

Simple Summary

Bronchoalveolar lavage is routinely collected during bronchoscopy for cytology analysis in the diagnostic of lung cancer. Due to low sensitivity of this method, early-stage cancers are undetected, lowering the treatment success. In this study, we analyzed extracellular vesicles isolated from bronchoalveolar lavage of lung cancer suspects by mass spectrometry-based proteomics. The protein composition of bronchoalveolar lavage extracellular vesicles of late-stage cancer showed a higher proteome complexity associated with mortality within the two year follow-up period. We identified a potential therapeutic target DNMT3B complex which was significantly expressed in bronchoalveolar lavage extracellular vesicles as well as in tumor tissue. Bronchoalveolar lavage extracellular vesicles proteome analysis of immune markers indicates the presence of markers of innate immune and fibroblast cells.

Abstract

Acellular bronchoalveolar lavage (BAL) proteomics can partially separate lung cancer from non-lung cancer patients based on principal component analysis and multivariate analysis. Furthermore, the variance in the proteomics data sets is correlated mainly with lung cancer status and, to a lesser extent, smoking status and gender. Despite these advances BAL small and large extracellular vehicles (EVs) proteomes reveal aberrant protein expression in paracrine signaling mechanisms in cancer initiation and progression. We consequently present a case-control study of 24 bronchoalveolar lavage extracellular vesicle samples which were analyzed by state-of-the-art liquid chromatography-mass spectrometry (LC-MS). We obtained evidence that BAL EVs proteome complexity correlated with lung cancer stage 4 and mortality within two years´ follow-up (p value = 0.006). The potential therapeutic target DNMT3B complex is significantly up-regulated in tumor tissue and BAL EVs. The computational analysis of the immune and fibroblast cell markers in EVs suggests that patients who deceased within the follow-up period display higher marker expression indicative of innate immune and fibroblast cells (four out of five cases). This study provides insights into the proteome content of BAL EVs and their correlation to clinical outcomes.

Blood biomarkers associated with inflammation predict poor prognosis in cerebral venous thrombosis:: a multicenter prospective observational study

BACKGROUND AND PURPOSE

Experimental studies suggest inflammation can contribute to blood barrier disruption and brain injury in cerebral venous thrombosis (CVT). We aimed to determine whether blood biomarkers of inflammation were associated with the evolution of brain lesions, persistent venous occlusion or functional outcome in patients with CVT.

METHODS

Pathophysiology of Venous Infarction-Prediction of Infarction and Recanalization in CVT (PRIORITy-CVT) was a multicenter prospective cohort study of patients with newly diagnosed CVT. Evaluation of neutrophil-to-lymphocyte ratio (NLR) and C-reactive protein (CRP) concentrations in peripheral blood samples was performed at admission in 62 patients. Additional quantification of interleukin (IL)-6 was performed at day 1, 3 and 8 in 35 patients and 22 healthy controls. Standardized magnetic resonance imaging was performed at day 1, 8 and 90. Primary outcomes were early evolution of brain lesion, early recanalization and functional outcome at 90 days.

RESULTS

Interleukin-6 levels were increased in patients with CVT with a peak at baseline. IL-6, NLR and CRP levels were not related with brain lesion outcomes or early recanalization but had a significant association with unfavourable functional outcome at 90 days (IL-6: OR = 1.28, 95% CI: 1.05-1.56, P = 0.046; NLR: OR = 1.39, 95% CI: 1.4-1.87, P = 0.014; CRP: OR = 1.756, 95% CI: 1.010-3.051, P = 0.029). Baseline IL-6 had the best discriminative capacity, with an area under the receiver operating characteristic curve to predict unfavourable functional outcome of 0.74 (P = 0.031).

CONCLUSIONS

Increased baseline levels of NLR, CRP and IL-6 may serve as new predictive markers of worse functional prognosis at 90 days in patients with CVT. No association was found between inflammatory markers and early evolution of brain lesion or venous recanalization.

Influenza A virus ribonucleoproteins form liquid organelles at endoplasmic reticulum exit sites

Influenza A virus has an eight-partite RNA genome that during viral assembly forms a complex containing one copy of each RNA. Genome assembly is a selective process driven by RNA-RNA interactions and is hypothesized to lead to discrete punctate structures scattered through the cytosol. Here, we show that contrary to the accepted view, formation of these structures precedes RNA-RNA interactions among distinct viral ribonucleoproteins (vRNPs), as they assemble in cells expressing only one vRNP type. We demonstrate that these viral inclusions display characteristics of liquid organelles, segregating from the cytosol without a delimitating membrane, dynamically exchanging material and adapting fast to environmental changes. We provide evidence that viral inclusions develop close to endoplasmic reticulum (ER) exit sites, depend on continuous ER-Golgi vesicular cycling and do not promote escape to interferon response. We propose that viral inclusions segregate vRNPs from the cytosol and facilitate selected RNA-RNA interactions in a liquid environment.

Influenza A virus forms cytosolic inclusions containing viral ribonucleoproteins. Here, the authors show that viral inclusions form juxtaposed the endoplasmic reticulum and have liquid properties, likely constituting sites of assembly of epidemic and pandemic influenza genomes.

Characterization of spermatogonial cells and niche in the scorpion mud turtle (Kinosternon scorpioides)

Undifferentiated spermatogonia (A_und) or spermatogonial stem cells (SSCs) are committed to the establishment and maintenance of spermatogenesis and fertility throughout a male's life and are located in a highly specialized microenvironment called niche that regulates their fate. Although several studies have been developed on SSCs in mammalian testis, little is known about other vertebrate classes. The present study is the first to perform a more detailed investigation on the spermatogonial cells and their niche in a reptilian species. Thus, we characterized A_und/SSCs and evaluated the existence of SSCs niche in the Kinosternon scorpioides, a freshwater turtle found from Mexico to northern and central South America. Our results showed that, in this species, A_und/SSCs exhibited a nuclear morphological pattern similar to those described for other mammalian species already investigated. However, in comparison to other spermatogonial cell types, A_und/SSCs presented the largest nuclear volume in this turtle. Similar to some mammalian and fish species investigated, both GFRA1 and CSF1 receptors were expressed in A_und/SSCs in K. scorpioides. Also, as K. scorpioides A_und/SSCs were preferentially located near blood vessels, it can be suggested that this niche characteristic is a well conserved feature during evolution. Besides being valuable for comparative reproductive biology, our findings represent an important step towards the understanding of SSCs biology and the development of valuable systems/tools for SSCs culture and cryopreservation in turtles. Moreover, we expect that the above-mentioned results will be useful for reproductive biotechnologies as well as for governmental programs aiming at reptilian species conservation.

PLK4 is a microtubule-associated protein that self-assembles promoting de novo MTOC formation

The centrosome is an important microtubule-organising centre (MTOC) in animal cells. It consists of two barrel-shaped structures, the centrioles, surrounded by the pericentriolar material (PCM), which nucleates microtubules. Centrosomes can form close to an existing structure (canonical duplication) or de novo. How centrosomes form de novo is not known. The master driver of centrosome biogenesis, PLK4, is critical for the recruitment of several centriole components. Here, we investigate the beginning of centrosome biogenesis, taking advantage of Xenopus egg extracts, where PLK4 can induce de novo MTOC formation ( Eckerdt et al., 2011; Zitouni et al., 2016). Surprisingly, we observe that in vitro, PLK4 can self-assemble into condensates that recruit α- and β-tubulins. In Xenopus extracts, PLK4 assemblies additionally recruit STIL, a substrate of PLK4, and the microtubule nucleator γ-tubulin, forming acentriolar MTOCs de novo. The assembly of these robust microtubule asters is independent of dynein, similar to what is found for centrosomes. We suggest a new mechanism of action for PLK4, where it forms a self-organising catalytic scaffold that recruits centriole components, PCM factors and α- and β-tubulins, leading to MTOC formation.

This article has an associated First Person interview with the first author of the paper.

Summary: PLK4 binds to microtubules and self-assembles into condensates that recruit tubulin and trigger de novo microtubule-organising centre formation in vitro.

Influenza A virus ribonucleoproteins modulate host recycling by competing with Rab11 effectors

Influenza A virus assembly is an unclear process, whereby individual virion components form an infectious particle. The segmented nature of the influenza A genome imposes a problem to assembly because it requires packaging of eight distinct RNA particles (vRNPs). It also allows genome mixing from distinct parental strains, events associated with influenza pandemic outbreaks. It is important to public health to understand how segmented genomes assemble, a process that is dependent on the transport of components to assembly sites. Previously, it has been shown that vRNPs are carried by recycling endosome vesicles, resulting in a change of Rab11 distribution. Here, we describe that vRNP binding to recycling endosomes impairs recycling endosome function, by competing for Rab11 binding with family-interacting proteins, and that there is a causal relationship between Rab11 ability to recruit family-interacting proteins and Rab11 redistribution. This competition reduces recycling sorting at an unclear step, resulting in clustering of single- and double-membraned vesicles. These morphological changes in Rab11 membranes are indicative of alterations in protein and lipid homeostasis during infection. Vesicular clustering creates hotspots of the vRNPs that need to interact to form an infectious particle.

Diet and medication in the treatment of hyperuricemia in hypertensive patients

OBJECTIVE

To evaluate the effects of diet and medication, either isolated or associated, on serum levels of uric acid in patients with hyperuricemia.

METHODS

We studied patients from the Hypertension Unit of the University of Goias who had hyperuricemia (men > or =8.5 mg/dL and women > or =7.5 mg/dL). We divided the patients into three groups: G1 (low purine diet), G2 (low purine diet + medication), and G3 (medication only). Patients received allopurinol, 150 mg/day titrated up to 300 mg/dL when necessary. Patients were evaluated with regards to their lifestyles (diet, smoking, physical, activity, alcohol consumption), uric acid, blood pressure, use of medication, body mass index, cholesterol, and triglyceride. Follow-up took place in weeks 0 (M1), 6 (M2), 12 (M3) during the intervention and in week 36 (M4) after the study was completed.

RESULTS

Fifty-five patients participated in the study, 31 women, mean age 54.4+/-10.6 years, body mass index 28.6+/-3.9 kg/m2. A similar reduction (p<0.001) in uric acid levels occurred in the three intervention groups. In week 36 (M4), after 24 weeks without intervention, a tendency toward elevation of uricemia was noted in G2 and G3, and a continuous drop in uricemia was noted in G1. No significant modifications were observed in the other variables analyzed.

CONCLUSION

Considering the cost x benefit relationship, a diet low in purine should be the 1st therapeutic option for controlling hyperuricemia in patients with similar characteristic to the ones presented in this study.

[Different therapies in the treatment of obesity in hypertensive patients]

PURPOSE

To evaluate the efficacy and tolerability of different therapies associated with diet in the treatment of hypertensive obese patients.

METHODS

In a clinical study we randomly evaluated 39 hypertensive obese patients (body mass index (BMI) > or = 30 kg/m2). After 45 days of diet the patients were again randomly distributed in 3 groups and received in double blind way: group 1-hypocaloric diet+placebo; group 2-hypocaloric diet+dexfenfluramine; group 3-hypocaloric diet+spiruline+fucus+gelatin. We followed their progress during 12 weeks under medication and further 24 weeks without. We evaluated the groups comparing: weight, BMI, blood pressure and side-effects.

RESULTS

Twenty seven patients completed the observation. In those patients from groups 1 and 3 no changes in any of parameters were observed. In group 2 we observed a clear loss of weight (-3.8 Kg) and a fall in BMI. Blood Pressure changes were only observed in group 2 (-9.6%). The only patients to maintain weight loss after the termination of use of medicines were those from group 2. We did not observe any side-effects.

CONCLUSION

In hypertensive obese patients, when isolated diet is not enough to control weight loss, dexfenfluramine could be useful in association with a controlled diet. The drug assists in weight loss, does not promote side-effects and does not interfere in the treatment of blood pressure.

[Multidisciplinary experience in the approach to the hypertensive patient]

PURPOSE

To evaluate the impact of the educational activities on the approach of patients with hypertension, with an interdisciplinary team.

METHODS

Fifty patients divided into two groups: A) with 25 patients who participated in educational activities in the Hypertension League (HL) and B) who were also registered and did not take part in the activities. They were studied regarding blood pressure (BP), weight control, smoking habits, alcoholic beverage consumption, physical activities and frequency of medical care.

RESULTS

There was a drop in BP of 84% of the patients in group A and 88% in group B, a drop in weight in 60% of group A and 44% of group B. We registered the presence of 4% of smokers in group A and 16% in group B. Physical activities were regular in 56% of group A and 36% in group B. Absenteeism to meetings was slightly higher among group B (44%) when compared with group A (30%).

CONCLUSION

In spite of not having observed any significant differences between both approaches, regarding to strict BP control, we were able to observe a noticeable advantage in favor of the educational approach to the group, with participation of interdisciplinary team.