The cytolethal distending toxin (CDT) is produced by several Gram-negative pathogenic bacteria. In addition to inflammation, experimental evidences are in favor of a protumoral role of CDT-harboring ...bacteria such as
Escherichia coli
,
Campylobacter jejuni
, or
Helicobacter hepaticus
. CDT may contribute to cell transformation
in vitro
and carcinogenesis in mice models, through the genotoxic action of CdtB catalytic subunit. Here, we investigate the mechanism of action by which CDT leads to genetic instability in human cell lines and colorectal organoids from healthy patients’ biopsies. We demonstrate that CDT holotoxin induces a replicative stress dependent on CdtB. The slowing down of DNA replication occurs mainly in late S phase, resulting in the expression of fragile sites and important chromosomic aberrations. These DNA abnormalities induced after CDT treatment are responsible for anaphase bridge formation in mitosis and interphase DNA bridge between daughter cells in G1 phase. Moreover, CDT-genotoxic potential preferentially affects human cycling cells compared to quiescent cells. Finally, the toxin induces nuclear distension associated to DNA damage in proliferating cells of human colorectal organoids, resulting in decreased growth. Our findings thus identify CDT as a bacterial virulence factor targeting proliferating cells, such as human colorectal progenitors or stem cells, inducing replicative stress and genetic instability transmitted to daughter cells that may therefore contribute to carcinogenesis. As some CDT-carrying bacterial strains were detected in patients with colorectal cancer, targeting these bacteria could be a promising therapeutic strategy.
The mammalian 20S catalytic core of the proteasome is made of 14 different subunits (α1-7 and β1-7) but exists as different subtypes depending on the cell type. In immune cells, for instance, ...constitutive catalytic proteasome subunits can be replaced by the so-called immuno-catalytic subunits, giving rise to the immunoproteasome. Proteasome activity is also altered by post-translational modifications (PTMs) and by genetic variants. Immunochemical methods are commonly used to investigate these PTMs whereby protein-tagging is necessary to monitor their effect on 20S assembly. Here, we present a new miniaturized workflow combining top-down and bottom-up mass spectrometry of immunopurified 20S proteasomes that analyze the proteasome assembly status as well as the full proteoform footprint, revealing PTMs, mutations, single nucleotide polymorphisms (SNPs) and induction of immune-subunits in different biological samples, including organoids, biopsies and B-lymphoblastoid cell lines derived from patients with proteasome-associated autoinflammatory syndromes (PRAAS). We emphasize the benefits of using top-down mass spectrometry in preserving the endogenous conformation of protein modifications, while enabling a rapid turnaround (1 h run) and ensuring high sensitivity (1-2 pmol) and demonstrate its capacity to semi-quantify constitutive and immune proteasome subunits.
Wolfram syndrome is an early onset genetic disease (1/180,000) featuring diabetes mellitus and optic neuropathy, associated to mutations in the WFS1 gene. Wfs1-/- mouse model shows pancreatic beta ...cell atrophy, but its visual performance has not been investigated, prompting us to study its visual function and histopathology of the retina and optic nerve. Electroretinogram and visual evoked potentials (VEPs) were performed in Wfs1-/- and Wfs1+/+ mice at 3, 6, 9 and 12 months of age. Fundi were pictured with Micron III apparatus. Retinal ganglion cell (RGC) abundance was determined from Brn3a immunolabeling of retinal sections. RGC axonal loss was quantified by electron microscopy in transversal optic nerve sections. Endoplasmic reticulum stress was assessed using immunoglobulin binding protein (BiP), protein disulfide isomerase (PDI) and inositol-requiring enzyme 1 alpha (Ire1α) markers. Electroretinograms amplitudes were slightly reduced and latencies increased with time in Wfs1-/- mice. Similarly, VEPs showed decreased N+P amplitudes and increased N-wave latency. Analysis of unfolded protein response signaling revealed an activation of endoplasmic reticulum stress in Wfs1-/- mutant mouse retinas. Altogether, progressive VEPs alterations with minimal neuronal cell loss suggest functional alteration of the action potential in the Wfs1-/- optic pathways.
Limited mouth opening (LMO) is a frequent complication of systemic sclerosis (SS). Its management is complex and there are limited treatment options. We report four patients with SS and severe LMO ...interincisal distance (IID) <30 mm treated with pulsed carbon dioxide (CO2) laser. Pulsed CO2 laser treatment of the white lips was performed after all patients had signed a written informed consent in the absence of alternative treatment. Treatment was carried out under locoregional anaesthesia using a Sharplan 30C CO2 laser in the Silk Touch® resurfacing mode. One to three laser sessions were performed at intervals of 8-12 months between sessions. Assessments were performed at 3 and 12 months with measurement of the IID using a ruler, calculation of the Mouth Handicap in Systemic Sclerosis (MHISS) scale and global evaluation by the patients. Adverse events were also reported. In all four patients, an improvement in IID occurred 3 months after the first session with a mean gain of +5 mm (range: 2-7). At 12 months, a mean gain of +8.5 mm (range: 7-10) in IID was observed. The MHISS score decreased by a mean of -14 (range: 11-17). All patients showed improvement of lip flexibility or mouth opening, allowing better phonation and mastication and easier dental care. Adverse effects were transient erythema and/or dyschromia. CO2 laser appears to be effective and well tolerated in the improvement of LMO in SS.
We review current knowledge and understanding of the biology and ecology of the calanoid copepod Calanus helgolandicus in European waters, as well as provide a collaborative synthesis of data from 18 ...laboratories and 26 sampling stations in areas distributed from the northern North Sea to the Aegean and Levantine Seas. This network of zooplankton time-series stations has enabled us to collect and synthesise seasonal and multi-annual data on abundance, body size, fecundity, hatching success and vertical distribution of C. helgolandicus. An aim was to enable comparison with its congener Calanus finmarchicus, which has been studied intensively as a key component of European and north east Atlantic marine ecosystems. C. finmarchicus is known to over-winter at depth, whereas the life-cycle of C. helgolandicus is less well understood. Overwintering populations of C. helgolandicus have been observed off the Atlantic coast between 400 and 800 m, while in the Mediterranean there is evidence of significant deep-water populations at depths as great as 4200 m. The biogeographical distribution of C. helgolandicus in European coastal waters covers a wide range of habitats, from open ocean to coastal environments, and its contribution to mesozooplankton biomass ranges from 6% to 93%. Highest abundances were recorded in the Adriatic and off the west coast of Spain. C. helgolandicus is generally found in 9-20 C water, with maximum abundances from 13-17 C. In contrast, C. finmarchicus is found in cooler water between 0 and 15 C, with peak abundances from 0 to 9 C. As water has warmed in the North Atlantic over recent decades, the range of C. helgolandicus and its abundance on the fringes of its expanding range have increased. This review will facilitate development of population models of C. helgolandicus. This will not only help answer remaining questions but will improve our ability to forecast future changes, in response to a warming climate, in the abundance and distribution of this important species.
Hepatitis C virus (HCV)-related liver disease is a cause of significant morbidity and mortality worldwide. Currently, direct-acting antiviral drugs (DAAs) are associated with an increased sustained ...virologic response (SVR) and are the gold standard for treating HCV infection.
The new combination of grazoprevir, an inhibitor of HCV NS3/4A, and elbasvir, an inhibitor of HCV NS5A, once daily will be available for the treatment of HCV infection. This combination therapy has a high efficacy in HCV genotype 1 and 4 infections, inducing a SVR up to 95%, even in difficult to treat patients such as cirrhotic, HIV co-infected, or dialysis-dependent patients, and patients with stage 4-5 chronic kidney disease or those who failed previous therapy. The safety of grazoprevir combined with elbasvir is very good and without significant adverse effects in phase 2 or 3 studies. For patients who failed prior DAA therapy, in vitro and in vivo studies showed that the grazoprevir and elbasvir combination is fully active against resistance to NS3/4A protease inhibitors. Resistance to NS5B inhibitors is least susceptible to grazoprevir or elbasvir.
This new combination of gazoprevir with elbasvir offers an opportunity to cure HCV infection with short interferon-free therapy, even in difficult to treat patients.
Estrogens, such as the 17β-estradiol (E2) and the 17α-ethinylestradiol (EE2), have been regarded as a global threat to aquatic ecosystems due to their pseudo-persistence, their high estrogenic ...activity and their toxicity towards non-target species. Data regarding their ecotoxicological effects on marine calanoid copepods are very scarce. In this study, the calanoid copepod Acartia clausi was used as a model organism for estrogens exposure in marine pelagic ecosystems. Lethal effects of estrogens on A. clausi life-stages (Embryos, one day old nauplii: N1, three day old nauplii: N3, copepodites: C1-C3 and adults: C6) were investigated using 48 h acute tests. Copepods showed stage-specific responses against E2 and EE2 acute exposure. The most resistant life stage was N1 with LC50 values > 1500 μg L-1 and >5000 μg L-1, respectively for E2 and EE2. For N3, C1-C3, and C6, sensitivity to estrogens decreased with age and survival was affected at concentrations above those detected in the environment reflecting low estrogens acute toxicity for these life stages. In contrast, embryonic stage revealed high vulnerability to E2 and EE2 acute effects. Embryos showed non-monotonic dose-response and hatching success was significantly reduced at low realistic concentrations of E2 (0.005, 0.5, and 5 μg L-1) and EE2 (0.05 and 5 μg L-1).
Survival, development and sex ratio of A. clausi to EE2 exposure at 1 and 100 μg L-1 were also determined during a life cycle experiment. Fitness of the females of the generation F0 was evaluated by measuring lifespan, prosome length and egg production. The main observed effects were the decrease of females’ prosome length, the feminization of the population and the reduction of the egg production for the generation F0 at 100 μg L-1 of EE2. This concentration is above those reported in the environment indicating the tolerance of A. clausi to EE2 at environmentally relevant concentrations.
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•First knowledge on Acartia clausi response to acute and chronic estrogens exposure.•Estrogens exhibit a U-shape curve for A. clausi embryos.•Survival of N1 life stage of A. clausi was not sensitive to E2 and EE2 exposure.•Sex ratio was skewed towards females at 100 μg L-1 of EE2.•Reproduction and prosome length were reduced in females reared with 100 μg L-1 of EE2.
AIM:To assess,in a routine practice setting,the sus-tained virologic response(SVR) to telaprevir(TPV) or boceprevir(BOC) in hepatitis C virus(HCV) nullresponders or relapsers with severe liver ...fibrosis.METHODS:One hundred twenty-five patients were treated prospectively for 48 wk with TPV or BOC + pegylated-interferon(peg-INF) α2a + ribavirin(PR) according to standard treatment schedules without randomization.These patients were treated in routine practice settings in 10 public or private health care centers,and the data were prospectively collected.Only patients with severe liver fibrosis(Metavir scores of F3 or F4 upon liver biopsy or liver stiffness assessed by elastography),genotype 1 HCV and who were null-responders or relapsers to prior PR combination therapy were included in this study.RESULTS:The Metavir fibrosis scores were F3 in 35(28%) and F4 in 90(72%) of the patients.In total,62.9% of the patients were null-responders and 37.1% relapsers to the previous PR therapy.The overall SVR rate at 24 wk post-treatment withdrawal was 59.8%.The SVR was 65.9% in the TPV group and 44.1% in the BOC group.Independent predictive factors of an SVR included a response to previous treatment,relapsers vs null-responders OR = 3.9;(1.4,10.6),P = 0.0084,a rapid virological response(RVR) OR 6.9(2.6,18.2),P = 0.001 and liver stiffness lower than 21.3 kPa OR = 8.2(2.3,29.5),P = 0.001.During treatment,63 patients(50.8%) had at least one severe adverse event(SAE) of grade 3 or 4.A multivariate analysis identified two factors associated with SAEs:female gender OR = 2.4(1.1,5.6),P = 0.037 and a platelet count below 150 × 103/ mm3 OR = 5.3(2.3,12.4),P ≤ 0.001.CONCLUSION:More than half of these difficult-to-treat patients achieved an SVR and had SAEs in an actual practice setting.The SVR rate was influenced by the response to previous PR treatment,the RVR and liver stiffness.
Microplastics have been reported everywhere around the globe. With very limited human activities, the Arctic is distant from major sources of microplastics. However, microplastic ingestions have been ...found in several Arctic marine predators, confirming their presence in this region. Nonetheless, existing information for this area remains scarce, thus there is an urgent need to quantify the contamination of Arctic marine waters. In this context, we studied microplastic abundance and composition within the zooplankton community off East Greenland. For the same area, we concurrently evaluated microplastic contamination of little auks (Alle alle), an Arctic seabird feeding on zooplankton while diving between 0 and 50 m. The study took place off East Greenland in July 2005 and 2014, under strongly contrasted sea-ice conditions. Among all samples, 97.2% of the debris found were filaments. Despite the remoteness of our study area, microplastic abundances were comparable to those of other oceans, with 0.99 ± 0.62 m−3 in the presence of sea-ice (2005), and 2.38 ± 1.11 m−3 in the nearby absence of sea-ice (2014). Microplastic rise between 2005 and 2014 might be linked to an increase in plastic production worldwide or to lower sea-ice extents in 2014, as sea-ice can represent a sink for microplastic particles, which are subsequently released to the water column upon melting. Crucially, all birds had eaten plastic filaments, and they collected high levels of microplastics compared to background levels with 9.99 and 8.99 pieces per chick meal in 2005 and 2014, respectively. Importantly, we also demonstrated that little auks took more often light colored microplastics, rather than darker ones, strongly suggesting an active contamination with birds mistaking microplastics for their natural prey. Overall, our study stresses the great vulnerability of Arctic marine species to microplastic pollution in a warming Arctic, where sea-ice melting is expected to release vast volumes of trapped debris.
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•Microplastic concentration of East Greenland was similar to other oceanic basins.•Microplastics were more abundant when sea-ice was absent.•100% of little auks were contaminated with microplastics.•Little auks mistook microplastics for their zooplankton prey.•97% of debris were filaments.
Microplastic pollution is significant in the Greenland Sea, despite its remoteness. Local seabirds mistake microplastics for their zooplankton prey, and all of them are contaminated.
Although direct-acting antivirals have been used extensively to treat patients with chronic hepatitis C virus (HCV) infection, their clinical effectiveness has not been well reported. We compared the ...incidence of death, hepatocellular carcinoma, and decompensated cirrhosis between patients treated with direct-acting antivirals and those untreated, in the French ANRS CO22 Hepather cohort.
We did a prospective study in adult patients with chronic HCV infection enrolled from 32 expert hepatology centres in France. We excluded patients with chronic hepatitis B, those with a history of decompensated cirrhosis, hepatocellular carcinoma, or liver transplantation, and patients who were treated with interferon-ribavirin with or without first-generation protease inhibitors. Co-primary study outcomes were incidence of all-cause mortality, hepatocellular carcinoma, and decompensated cirrhosis. The association between direct-acting antivirals and these outcomes was quantified using time-dependent Cox proportional hazards models. This study is registered with ClinicalTrials.gov, number NCT01953458.
Between Aug 6, 2012, and Dec 31, 2015, 10 166 patients were eligible for the study. 9895 (97%) patients had available follow-up information and were included in analyses. Median follow-up was 33·4 months (IQR 24·0–40·7). Treatment with direct-acting antivirals was initiated during follow-up in 7344 patients, and 2551 patients remained untreated at the final follow-up visit. During follow-up, 218 patients died (129 treated, 89 untreated), 258 reported hepatocellular carcinoma (187 treated, 71 untreated), and 106 had decompensated cirrhosis (74 treated, 32 untreated). Exposure to direct-acting antivirals was associated with increased risk for hepatocellular carcinoma (unadjusted hazard ratio HR 2·77, 95% CI 2·07–3·71) and decompensated cirrhosis (3·83, 2·29–6·42). After adjustment for variables (age, sex, body-mass index, geographical origin, infection route, fibrosis score, HCV treatment-naive, HCV genotype, alcohol consumption, diabetes, arterial hypertension, biological variables, and model for end-stage liver disease score in patients with cirrhosis), exposure to direct-acting antivirals was associated with a decrease in all-cause mortality (adjusted HR 0·48, 95% CI 0·33–0·70) and hepatocellular carcinoma (0·66, 0·46–0·93), and was not associated with decompensated cirrhosis (1·14, 0·57–2·27).
Treatment with direct-acting antivirals is associated with reduced risk for mortality and hepatocellular carcinoma and should be considered in all patients with chronic HCV infection.
INSERM-ANRS (France Recherche Nord & Sud Sida-HIV Hépatites), ANR (Agence Nationale de la Recherche), DGS (Direction Générale de la Santé), MSD, Janssen, Gilead, AbbVie, Bristol-Myers Squibb, and Roche.
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