Respiratory syncytial virus ribonucleoproteins hijack microtubule Rab11 dependent transport for intracellular trafficking.

Respiratory syncytial virus (RSV) is the primary cause of severe respiratory infection in infants worldwide. Replication of RSV genomic RNA occurs in cytoplasmic inclusions generating viral ribonucleoprotein complexes (vRNPs). vRNPs then reach assembly and budding sites at the plasma membrane. However, mechanisms ensuring vRNPs transportation are unknown. We generated a recombinant RSV harboring fluorescent RNPs allowing us to visualize moving vRNPs in living infected cells and developed an automated imaging pipeline to characterize the movements of vRNPs at a high throughput. Automatic tracking of vRNPs revealed that around 10% of the RNPs exhibit fast and directed motion compatible with transport along the microtubules. Visualization of vRNPs moving along labeled microtubules and restriction of their movements by microtubule depolymerization further support microtubules involvement in vRNPs trafficking. Approximately 30% of vRNPs colocalize with Rab11a protein, a marker of the endosome recycling (ER) pathway and we observed vRNPs and Rab11-labeled vesicles moving together. Transient inhibition of Rab11a expression significantly reduces vRNPs movements demonstrating Rab11 involvement in RNPs trafficking. Finally, Rab11a is specifically immunoprecipitated with vRNPs in infected cells suggesting an interaction between Rab11 and the vRNPs. Altogether, our results strongly suggest that RSV RNPs move on microtubules by hijacking the ER pathway.

The ESX-4 substrates, EsxU and EsxT, modulate Mycobacterium abscessus fitness.

ESX type VII secretion systems are complex secretion machineries spanning across the mycobacterial membrane and play an important role in pathogenicity, nutrient uptake and conjugation. We previously reported the role of ESX-4 in modulating Mycobacterium abscessus intracellular survival. The loss of EccB4 was associated with limited secretion of two effector proteins belonging to the WXG-100 family, EsxU and EsxT, and encoded by the esx-4 locus. This prompted us to investigate the function of M. abscessus EsxU and EsxT in vitro and in vivo. Herein, we show that EsxU and EsxT are substrates of ESX-4 and form a stable 1:1 heterodimer that permeabilizes artificial membranes. While expression of esxU and esxT was up-regulated in M. abscessus-infected macrophages, their absence in an esxUT deletion mutant prevented phagosomal membrane disruption while maintaining M. abscessus in an unacidified phagosome. Unexpectedly, the esxUT deletion was associated with a hyper-virulent phenotype, characterised by increased bacterial loads and mortality in mouse and zebrafish infection models. Collectively, these results demonstrate that the presence of EsxU and EsxT dampens survival and persistence of M. abscessus during infection.

Ribonucleoprotein transport in Negative Strand RNA viruses.

Negative-sense, single-stranded RNA (-ssRNA) viruses comprise some of the deadliest human pathogens (Ebola, rabies, influenza A viruses etc.). Developing therapeutic tools relies on a better understanding of their multiplication cycle. For these viruses, the genome replication and transcription activities most-often segregate in membrane-less environments called inclusion bodies (IBs) or viral factories. These "organelles" usually locate far from the cell surface from where new virions are released, and -ssRNA viruses do not encode for transport factors. The efficient trafficking of the genome progeny toward the cell surface is most often ensured by mechanisms co-opting the cellular machineries. In this review, for each -ssRNA viral family, we cover the methods employed to characterize these host-virus interactions, the strategies used by the viruses to promote the virus genome transport, and the current gaps in the literature. Finally, we highlight how Rab11 has emerged as a target of choice for the intracellular transport of -ssRNA virus genomes.

Labeled TEMPO-Oxidized Mannan Differentiates Binding Profiles within the Collectin Families.

Establishing the rapid and accurate diagnosis of sepsis is a key component to the improvement of clinical outcomes. The ability of analytical platforms to rapidly detect pathogen-associated molecular patterns (PAMP) in blood could provide a powerful host-independent biomarker of sepsis. A novel concept was investigated based on the idea that a pre-bound and fluorescent ligand could be released from lectins in contact with high-affinity ligands (such as PAMPs). To create fluorescent ligands with precise avidity, the kinetically followed TEMPO oxidation of yeast mannan and carbodiimide coupling were used. The chemical modifications led to decreases in avidity between mannan and human collectins, such as the mannan-binding lectin (MBL) and human surfactant protein D (SP-D), but not in porcine SP-D. Despite this effect, these fluorescent derivatives were captured by human lectins using highly concentrated solutions. The resulting fluorescent beads were exposed to different solutions, and the results showed that displacements occur in contact with higher affinity ligands, proving that two-stage competition processes can occur in collectin carbohydrate recognition mechanisms. Moreover, the fluorescence loss depends on the discrepancy between the respective avidities of the recognized ligand and the fluorescent mannan. Chemically modulated fluorescent ligands associated with a diversity of collectins may lead to the creation of diagnostic tools suitable for multiplex array assays and the identification of high-avidity ligands.

Characterisation of vaccine breakthrough infections of SARS-CoV-2 Delta and Alpha variants and within-host viral load dynamics in the community, France, June to July 2021.

We compared PCR results from SARS-CoV-2-positive patients tested in the community in France from 14 June to 30 July 2021. In asymptomatic individuals, Cq values were significantly higher in fully vaccinated than non-fully vaccinated individuals (effect size: 1.7; 95% CI: 1-2.3; p < 10-6). In symptomatic individuals and controlling for time since symptoms, the difference vanished (p = 0.26). Infections with the Delta variant had lower Cq values at symptom onset than with Alpha (effect size: -3.32; 95% CI: -4.38 to -2.25; p < 10-6).

Endocrine Causes of Hypertension.

PURPOSE OF REVIEW: To discuss selected endocrine causes of hypertension and to provide practical clinical recommendations regarding the evaluation and treatment of these disorders. RECENT FINDINGS: More than 15 endocrine disorders with varying rates of prevalence can cause hypertension. For example, primary aldosteronism may exist in up to 20% of patients with resistant hypertension. Recognition of these important secondary causes of hypertension is essential to provide contemporary targeted therapies in order to improve long-term disease outcomes. Clinicians must have a broad understanding of the prevalence, clinical presentation, and current diagnostic modalities for endocrine causes of hypertension to facilitate prompt referral, identification, and optimal management of these disorders. Endocrine causes of hypertension are multifactorial and, in some cases, widely prevalent. It is important for clinicians considering secondary causes of hypertension to be knowledgeable about the underlying pathophysiology of these disorders and to understand when additional evaluation and treatment may be needed.

Abdominal Distension and Vascular Collapse.

We present the case of a 43-year-old gentleman who presented to the emergency room with acute abdominal distension, confusion and vascular collapse. The emergent radiologic imaging obtained showed massive bilateral adrenal enlargement, but despite the initial clinical suspicion of possible overwhelming sepsis and/or massive abdominal/intralesional hemorrhage, lab tests based obtained rapidly confirmed the diagnosis of acute Addisonian crisis which responded dramatically to adrenocorticoid hormone replacement therapy and aggressive fluid resuscitation. The patient's established history of metastatic lung cancer confirmed this as a case of metastatic massive bilateral adrenal metastases with an initial presentation of acute adrenal insufficiency which is uncommon in the setting of metastatic carcinomatosis but more typically associated with lymphomas. Recognition of this clinical possibility is vital to enable rapid diagnosis and consequent life saving therapy.

[Retrospective analysis of the performance of the SARS-CoV-2 rapid antigen detection test compared to the reference RT-PCR test]. / Analyse rétrospective des performances du test de détection rapide antigénique du SARS-CoV-2 comparé au test de référence RT-PCR.

BACKGROUND: Discovered in 2019 in the region of Wuhan, China, the Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2) rapidly established itself as a major pathogenic agent of morbidity and mortality. France has implemented a strategy to fight this virus which relies essentially on widespread RT-PCR virological testing in order to isolate positive patients. Antigenic tests have recently been made available to help the diagnostics. We have conducted a retrospective study to determine the sensitivity of these antigenic tests, comparing them to the reference RT-PCR method. METHOD: Between December 7, 2020 and January 31, 2021, each patient we received in our laboratories for an RT-PCR test was enrolled. Out of 271,649 patients, 4,881 had been submitted to an antigenic test (TDR) in the preceding 24 hours. Comparing the data resulting from both tests, we established the sensitivity and the specificity of the antigenic tests. For our analysis we included the parameter of symptom and/or the value of Cycles threshold (Ct) in our parameters. RESULTS: The sensitivity of the TDRs compared to all the positive RT-PCR tests is 56%. We further demonstrate the correlation between the symptom duration and the reduction of the nasopharyngeal viral load. Based on this data, we have established that the sensitivity of the TDRs decreases very rapidly after symptom onset, contrary to the estimated viral load in the RT-PCR. Indeed, less the 24 hours after clinical symptom onset, the sensitivity of the TDRs decreases from 74% to 60%. By including the Ct value in our parameters, we have established that, despite a high viral load and clinical symptoms since 7 days or less, the sensitivity of the TDRs is 66%. Although, a high number of asymptomatic patients among carriers of SARS-CoV-2, we have estimated a specificity of 93% for our test. CONCLUSIONS: Performance in terms of sensitivity and specificity of the TDR, as assessed in practice, are inferior to those given by the manufacturer, which raises several questions. What is the impact of falsely negative results for patients carrying a high viral load? Are the implemented measures sufficient to prevent the epidemic?

The Interactome analysis of the Respiratory Syncytial Virus protein M2-1 suggests a new role in viral mRNA metabolism post-transcription.

Human respiratory syncytial virus (RSV) is a globally prevalent negative-stranded RNA virus, which can cause life-threatening respiratory infections in young children, elderly people and immunocompromised patients. Its transcription termination factor M2-1 plays an essential role in viral transcription, but the mechanisms underpinning its function are still unclear. We investigated the cellular interactome of M2-1 using green fluorescent protein (GFP)-trap immunoprecipitation on RSV infected cells coupled with mass spectrometry analysis. We identified 137 potential cellular partners of M2-1, among which many proteins associated with mRNA metabolism, and particularly mRNA maturation, translation and stabilization. Among these, the cytoplasmic polyA-binding protein 1 (PABPC1), a candidate with a major role in both translation and mRNA stabilization, was confirmed to interact with M2-1 using protein complementation assay and specific immunoprecipitation. PABPC1 was also shown to colocalize with M2-1 from its accumulation in inclusion bodies associated granules (IBAGs) to its liberation in the cytoplasm. Altogether, these results strongly suggest that M2-1 interacts with viral mRNA and mRNA metabolism factors from transcription to translation, and imply that M2-1 may have an additional role in the fate of viral mRNA downstream of transcription.

Differences in short-term food preferences following vertical sleeve gastrectomy and Roux-en-Y gastric bypass surgery.

Bariatric surgery is effective in reducing body weight and obesity-related comorbidities. This study examined differences in the short-term effect of Roux en Y gastric bypass (RYGB) and vertical sleeve gastrectomy (VSG) on the hedonic rating of food. Predominantly black women with complicated obesity and a BMI>50 g/m(2) completed a validated food preference questionnaire before and 1-3 months following surgery. Analysis of preference scores indicated that the preference for fat decreased with both surgeries. VSG also decreased the preference for sugar. Further studies are needed to evaluate long term effects of surgery on food preferences and to elucidate physiological mechanisms.

Phentermine and topiramate for the management of obesity: a review.

Obesity is now a major public health concern worldwide with increasing prevalence and a growing list of comorbidities and complications. The morbidity, mortality and reduced productivity associated with obesity and its complications result in a major burden to health care costs. Obesity is a complex chronic medical syndrome often with multiple different etiologic factors in individual patients. The long term successful management of obesity remains particularly challenging and invariably requires a multifaceted approach including lifestyle and behavioral modification, increased physical activity, and adjunctive pharmacotherapy. Bariatric surgery remains a last resort though at present it has the best results for achieving sustained robust weight loss. Obesity pharmacotherapy has been very limited in its role for long term obesity management because of the past history of several failed agents as well as the fact that presently available agents are few, and generally utilized as monotherapy. The recent FDA approval of the fixed drug combination of phentermine and extended release topiramate (topiramate-ER) (trade name Qsymia™) marks the first FDA approved combination pharmacotherapeutic agent for obesity since the Phen-Fen combination of the 1990s. This review details the history and clinical trial basis for the use of both phentermine and topiramate in obesity therapeutics as well as the results of clinical trials of their combination for obesity treatment in humans. The initial clinical approval trials offer evidence that this fixed drug combination offers synergistic potential for effective, robust and sustained weight loss with mean weight loss of at least 10% of baseline achieved and sustained for up to 2 years in over 50% of subjects treated. It is anticipated that this agent will be the first in a new trend of multi-agent combination therapy for the chronic adjunctive management of obesity.