Le Laboratoire P4 Inserm Jean Mérieux

The fragmentation of plastics in the marine environment represents one of the most persistent and complex challenges in contemporary environmental science. Over the past decade, a limited number of laboratory experiments and numerical modeling have shown that plastics do not fragment into uniform debris but instead undergo a cascade of fragmentation processes that govern particle size distributions, transport behavior, and ecological impacts. However, real-world examples of plastic fragmentation remain rare, despite being essential for calibrating and validating generic numerical models. There is therefore a strong need for data derived from natural systems, ideally based on large and statistically representative datasets.In Normandy, France, the Dollemard coastal landfill provides a unique opportunity to address this issue through the study of a traceable anthropogenic marker: VALSTAR brand beer bottle caps. Manufactured from polyethylene, these caps were deposited in very large quantities from the 1960s to the 1990s. Due to ongoing coastal erosion, they continue to be released and are now found in significant numbers within the adjacent marine environment.The surfaces of these bottle caps exhibit advanced degradation, with numerous microplastics still attached to the remaining material. Systematic microscopic photographs of the degraded surfaces were acquired and automatically analyzed to quantify the number, size, and shape parameters of the attached microplastics. In parallel, a surface degradation index was established for the upper face of each cap, combined with a weighting method to estimate mass balance. From a total collection of 787 recovered caps, a representative subset of 107 was analyzed in detail. In addition, a single bottle cap was artificially aged in a UV chamber under controlled conditions to better isolate and characterize the role of UV radiation in the fragmentation process.The results demonstrate the coexistence of two fragmentation mechanisms: surface ablation and macro-fragmentation. Macro-fragmentation remains a secondary process, accounting for only 16% of the cases observed in the total dataset. UV-induced degradation does not appear to govern fragmentation at the scale of the smallest microplastics (µm range). Instead, it influences the particle size distribution of larger microplastics in the millimeter range. Thus, a clear bimodal size distribution is observed in the dataset, with a dominant population centered around an equivalent diameter of approximately 45 µm, and a secondary population of larger fragments, ranging from 0.8 to 0.9 mm. Comparing pristine caps, caps recovered in situ from landfills, and caps from marine settings allows a first-order estimation of fragmentation kinetics over the past 40 years. This comparison suggests an average mass loss of approximately 3.9% for the caps in the studied collection.

ABSTRACT Crimean-Congo hemorrhagic fever virus (CCHFV) is a virus that causes severe liver dysfunctions and hemorrhagic fever, with high mortality rate. Here, we show that CCHFV infection caused a massive lipidation of LC3 in hepatocytes. This lipidation was not dependent on ATG5, ATG7 or BECN1, and no signs for recruitment of the alternative ATG12–ATG3 pathway for lipidation was found. Both virus replication and protein synthesis were required for the lipidation of LC3. Despite an augmented transcription of SQSTM1, the amount of proteins did not show a massive and sustained increase in infected cells, indicating that degradation of SQSTM1 by macroautophagy/autophagy was still occurring. The genetic alteration of autophagy did not influence the production of CCHFV particles demonstrating that autophagy was not required for CCHFV replication. Thus, the results indicate that CCHFV multiplication imposes an overtly elevated level of LC3 mobilization that involves a possibly novel type of non-canonical lipidation. Abbreviations: BECN1: Beclin 1; CCHF: Crimean-Congo hemorrhagic fever; CCHFV: Crimean-Congo hemorrhagic fever virus; CHX: cycloheximide; ER: endoplasmic reticulum; GFP: green fluorescent protein; GP: glycoproteins; MAP1LC3: microtubule associated protein 1 light chain 3; MOI: multiplicity of infection; n.i.: non-infected; NP: nucleoprotein; p.i.: post-infection; SQSTM1: sequestosome 1

Despite several clinical trials implemented, no antiviral drug could demonstrate efficacy against Ebola virus. In non-human primates, early initiation of polymerase inhibitors favipiravir and remdesivir improves survival, but whether they could be effective in patients is unknown. Here we analyze the impact of antiviral therapy by using a mathematical model that integrates virological and immunological data of 44 cynomolgus macaques, left untreated or treated with favipiravir. We estimate that favipiravir has a ~50% efficacy in blocking viral production, which results in reducing virus growth and cytokine storm while IFNα reduces cell susceptibility to infection. Simulating the effect of delayed initiations of treatment, our model predicts survival rates of 60% for favipiravir and 100% for remdesivir when treatment is initiated within 3 and 4 days post infection, respectively. These results improve the understanding of Ebola immuno-pathogenesis and can help optimize antiviral evaluation in future outbreaks.

In 2009, the co-circulation of H5N1 and H1N1pdm09 raised concerns that a reassortment event may lead to highly pathogenic influenza strains. H1N1pdm09 and H5N1 are able to infect the same target cells of the lower respiratory tract. To investigate the capacity of the emergence of reassortant viruses, we characterized viruses obtained from the co-infection of cells with H5N1 (A/Turkey/13/2006) and H1N1pdm09 (A/Lyon/969/2009 H1N1). In our analysis, all the screened reassortants possessed the PB2, HA, and NP segments from H5N1 and acquired one or two of the H1N1pdm09 segments. Moreover, the in vivo infections showed that the acquisition of the NS segment from H1N1pdm09 increased the virulence of H5N1 in mice. We conclude, therefore, that reassortment can occur between these two viruses, even if this process has never been detected in nature.

BACKGROUND. The pathogenesis of Ebola virus (EBOV) disease (EVD) is poorly characterized. The establishment of well-equipped diagnostic laboratories close to Ebola treatment centers (ETCs) has made it possible to obtain relevant virological and biological data during the course of EVD and to assess their association with the clinical course and different outcomes of the disease. METHODS. We were responsible for diagnosing EBOV infection in patients admitted to two ETCs in forested areas of Guinea. The pattern of clinical signs was recorded, and an etiological diagnosis was established by RT-PCR for EBOV infection or a rapid test for malaria and typhoid fever. Biochemical analyses were also performed. RESULTS. We handled samples from 168 patients between November 29, 2014, and January 31, 2015; 97 patients were found to be infected with EBOV, with Plasmodium falciparum coinfection in 18%. Overall mortality for EVD cases was 58%, rising to 86% if P. falciparum was also present. Viral load was higher in fatal cases of EVD than in survivors, and fatal cases were associated with higher aspartate aminotransferase (AST) and alanine aminotransferase (ALT), C-reactive protein (CRP), and IL-6 levels. Furthermore, regardless of outcome, EVD was characterized by higher creatine kinase (CPK), amylase, and creatinine levels than in febrile patients without EVD, with higher blood urea nitrogen (BUN) levels in fatal cases of EVD only. CONCLUSION. These findings suggest that a high viral load at admission is a marker of poor EVD prognosis. In addition, high AST, ALT, CRP, and IL-6 levels are associated with a fatal outcome of EVD. Damage to the liver and other tissues, with massive rhabdomyolysis and, probably, acute pancreatitis, is associated with EVD and correlated with disease severity. Finally, biochemical analyses provide substantial added value at ETCs, making it possible to improve supportive rehydration and symptomatic care for patients. FUNDING. The French Ministry of Foreign Affairs, the Agence Française de Développement, and Institut Pasteur.

BackgroundMalaria treatment is recommended for patients with suspected Ebola virus disease (EVD) in West Africa, whether systematically or based on confirmed malaria diagnosis. At the Ebola treatment center in Foya, Lofa County, Liberia, the supply of artemether–lumefantrine, a first-line antimalarial combination drug, ran out for a 12-day period in August 2014. During this time, patients received the combination drug artesunate–amodiaquine; amodiaquine is a compound with anti–Ebola virus activity in vitro. No other obvious change in the care of patients occurred during this period.MethodsWe fit unadjusted and adjusted regression models to standardized patient-level data to estimate the risk ratio for death among patients with confirmed EVD who were prescribed artesunate–amodiaquine (artesunate–amodiaquine group), as compared with those who were prescribed artemether–lumefantrine (artemether–lumefantrine group) and those who were not prescribed any antimalarial drug (no-antimalarial group).ResultsBetween June 5 and October 24, 2014, a total of 382 patients with confirmed EVD were admitted to the Ebola treatment center in Foya. At admission, 194 patients were prescribed artemether–lumefantrine and 71 were prescribed artesunate–amodiaquine. The characteristics of the patients in the artesunate–amodiaquine group were similar to those in the artemether–lumefantrine group and those in the no-antimalarial group. A total of 125 of the 194 patients in the artemether–lumefantrine group (64.4%) died, as compared with 36 of the 71 patients in the artesunate–amodiaquine group (50.7%). In adjusted analyses, the artesunate–amodiaquine group had a 31% lower risk of death than the artemether–lumefantrine group (risk ratio, 0.69; 95% confidence interval, 0.54 to 0.89), with a stronger effect observed among patients without malaria.ConclusionsPatients who were prescribed artesunate–amodiaquine had a lower risk of death from EVD than did patients who were prescribed artemether–lumefantrine. However, our analyses cannot exclude the possibility that artemether–lumefantrine is associated with an increased risk of death or that the use of artesunate–amodiaquine was associated with unmeasured patient characteristics that directly altered the risk of death.

Hendra virus (HeV) and Nipah virus (NiV) are closely related, recently emerged paramyxoviruses that form Henipavirus genus and are capable of causing considerable morbidity and mortality in a number of mammalian species, including humans. However, in contrast to many other species and despite expression of functional virus entry receptors, mice are resistant to henipavirus infection. We report here the susceptibility of mice deleted for the type I interferon receptor (IFNAR-KO) to both HeV and NiV. Intraperitoneally infected mice developed fatal encephalitis, with pathology and immunohistochemical features similar to what was found in humans. Viral RNA was found in the majority of analyzed organs, and sublethally infected animals developed virus-specific neutralizing antibodies. Altogether, these results reveal IFNAR-KO mice as a new small animal model to study HeV and NiV pathogenesis, prophylaxis, and treatment and suggest the critical role of type I interferon signaling in the control of henipavirus infection.

To the Editor: The production of specific point mutations in the p53 tumor suppressor gene, as can be induced by certain chemical carcinogens, is believed to contribute to the development of some occupational cancers. A model system for studying this process in vivo in humans is provided by workers who have been occupationally exposed to high levels of vinyl chloride (VC) and are at risk for the development of the sentinel neoplasm, angiosarcoma of the liver (ASL). This is because of the fact that the active metabolites of VC are known to form stable etheno-adenosine adducts in DNA that could result in A → T transversions. Such A → T transversions have been found in the DNA from two of four ASLs in VC-exposed workers studied to date (at the first base of codons 249 and 255),1 and similar mutations have not been identified in non-VC-induced ASLs.2 These mutations would result in amino acid substitutions in the encoded p53 proteins (Arg → Trp at 249 and Ile → Phe at 255). These amino acid substitutions occur in a highly conserved region of p53 that is believed to be critical to its tumor-suppressor function. Similar amino acid substitutions in this region of p53 occur frequently in human cancers and are thought to contribute to the development of the cancers. In certain cases, such amino acid substitutions produce a conformational change in the p53 protein that stabilizes the mutant protein from intracellular degradation (which is rapid for the wild-type protein, which has a short half-life), extending the half-life and resulting in intranuclear accumulations of the mutant protein. Such mutant p53 can be demonstrated by the use of a specific mouse monoclonal antibody (PAb240), which identifies an epitope between amino acids 212 and 217 that is normally concealed in the wild-type p53 but which is revealed in many mutant p53 proteins because of the aforementioned conformational changes produced in the mutants. We have been able to use a previously described enzyme-linked immunosorbent assay (ELISA) based on PAb240 3 to detect increased amounts of the mutant p53 protein (up to 0.84 ng/mL) in the extracellular supernatant of cells in culture (SW480) known to contain increased amounts of the mutant p53. This suggests that in a similar situation in vivo, in which individuals have tumors that contain p53 mutations, increased amounts of mutant p53 protein may be detectable in easily accessible extracellular biological fluids such as serum. Therefore, we have examined the expression of mutant p53 protein in 29 individuals from a previously described cohort of VC-exposed workers and unexposed control subjects.4 This group included: four VC-exposed workers with ASLs (two with p53 mutations and two without p53 mutations), one VC-exposed worker with hepatocellular carcinoma (HCC) without a p53 mutation, 18 VC exposed workers without ASLs, and five unexposed control subjects group-matched for age, sex, and race. In these individuals, tumor-tissue was analyzed by immunohistochemistry by using a modification of the technique of Cattoretti et al5 with mouse monoclonal antibody DO-1, and serum was analyzed by ELISA based on PAb240 as described previously.3 The two of four cases of ASL (50%) that were known to contain p53 mutations in their tumor DNA were found to have increased amounts of mutant p53 protein in their tumor tissue and serum, whereas the two cases of ASL and one case of HCC that were known not to contain p53 mutations in their tumor DNA were found not to have increased amounts of mutant p53 protein in their tumor tissue or serum. Because these results suggested that serum mutant p53 could be a valid surrogate for mutant p53 gene expression in tissue, we examined the serum mutant p53 in the 18 VC-exposed workers without ASLs and the five control subjects. Three of 18 exposed workers (16%) had elevated serum mutant p53, compared with none of the control subjects. All of the five p53 serum-positive individuals in this group had histories of potential high exposure to VC (greater than 10 years of work in an exposed job category and an estimated total dose greater than 1500 ppm-year), whereas the VC-exposed workers with lesser exposure were all serum-negative. These results suggest that the detection of serum mutant p53 protein may be a useful biomarker for the study of VC-induced carcinogenesis in exposed human populations. Steven J. Smith, MPH; Jiin-Chyuan Luo, MD, DrPH; Paul Brandt-Rauf, ScD, MD, DrPH Division of Environmental Health Sciences; Columbia University School of Public Health; New York, NY Marie-Jeanne Marion, PhD INSERM; Lyon, France