Unité de Technologies Chimiques et Biologiques pour la Santé

Erythropoietin (EPO) is a glycoprotein hormone primarily known for its central role in red blood cell production, but it is now also recognized for its immunomodulatory effects on a range of immune effectors. Several studies indicate that EPO helps regulate intestinal barrier integrity, although its effect on intraepithelial lymphocytes (IELs) is still unknown. Using multiparameter flow cytometry and both conventional and unsupervised analyses, we conducted an in-depth phenotypic assessment of IELs from the murine duodenum, jejunum, ileum and colon. Our results revealed that in EPO-treated C57BL/6 mice, the absolute IEL count in the colonic epithelium was more than twice that observed in control mice without changes in the frequencies of the various subpopulations, indicating a global increase. This was accompanied by integrin α4β7 overexpression. Furthermore, EPO treatment alters the intestinal microbiota, increasing bacterial load while reducing diversity, with a notable decrease in Muribaculaceae, a taxon involved in microbial cross-feeding. This alteration may contribute to epithelial imbalance and indirectly to the observed increase in IEL density. Importantly, EPO treatment did not trigger colonic mucosal inflammation, although the affected IELs show a microbiota-dependent decrease in CD8αα expression (known to downregulate IEL activity). The present study is the first to provide a phenotypic mapping of IEL populations in the digestive tract of C57BL/6 mice and highlighted a novel regulatory role of EPO on colonic IELs. These results raise important questions about the impact of exogenous EPO supplementation and endogenous EPO fluctuations on intestinal immune responses - particularly in the context of inflammatory diseases.

Pancreatic cancer is a lethal malignancy, frequently diagnosed at an advanced stage due to its asymptomatic progression. Current combinatorial therapies show the benefits of the multi-drug approach; however, the side effects of these therapeutic protocols remain severe. Therefore, there is an urgent need for new combination therapies that are better tolerated by patients. In this study, we highlight the interest of combining disulfiram, a repurposed anti-alcoholism drug, with gemcitabine, based on evidence of synergism between the two molecules. Liposomal formulations were then developed to deliver gemcitabine and its lipophilic prodrug 4-( N )-stearoyl-gemcitabine, and combined with disulfiram. The formulations were characterized for their size, polydispersity index, zeta-potential, encapsulation efficiency, and drug release profile. The 4-( N )-stearoyl-gemcitabine-loaded liposomes exhibited a more sustained release profile compared to gemcitabine-loaded liposomes. The combination of free gemcitabine with disulfiram significantly improved the in vitro efficacy of the molecule in gemcitabine-resistant pancreatic ductal adenocarcinoma cell line PANC-1. The synergistic effect was confirmed by the combination index analysis. In parallel we demonstrated that the delayed release of gemcitabine from the liposomes greatly influences the efficacy of the combination. This study provides a systematic comparison of the doses required to achieve synergy when administering free molecules versus molecules encapsulated in nanosystems. It demonstrates the importance of considering prolonged release in order to achieve the same results as with free molecules, and this should be considered when translating the study into preclinical and clinical settings. • Liposomes improved GEM stability and controlled drug release. • Synergy was observed in GEM/DSF and GEM-C18/DSF combinations in vitro. • DSF enhanced GEM effect by inhibiting drug resistance mechanisms.

Basidiomycete fungi are the main decomposers of dead wood with an impact on the global carbon cycle. Their degradative mechanisms have been well-studied under aerobic conditions. Here, we study their activity in oxygen-depleted environments. We use metaproteomics in a field study to identify active wood-decomposing fungi and their enzymes at different depths from the wood surface, including in oxygen-depleted conditions. In vitro, we observe that the brown-rot fungus Fomitopsis pinicola can grow on wood in complete anoxia. Using 13C solid-state NMR, we demonstrate the degradation of plant cell-wall polysaccharides and fungal growth in the absence of oxygen. Proteomic analyses reveal that F. pinicola switches from a Fenton chemistry-based process under aerobic conditions to the secretion of plant cell wall-active enzymes in anoxia. Our finding that wood decay fungi can thrive in complete anoxia provides a deeper understanding of lignocellulose degradation mechanisms in nature and raises opportunities for the development of bio-inspired anaerobic processes.

Epstein-Barr nuclear antigen 1 (EBNA1), a sequence-specific DNA binding protein of Epstein-Barr virus (EBV), is essential for viral genome replication and maintenance and is therefore an attractive target for the therapeutic intervention of EBV-associated cancers. Several EBNA1-specific inhibitors have demonstrated the ability to block EBNA1 function in vitro, but practical delivery strategies for these inhibitors in vivo are still lacking. Here, we report an intelligent hierarchical targeting theranostic nanosystem (denoted as mZGOCS@MnO2-P5) that integrates an azide (N3) terminal dual-targeting peptide (N3-P5), a tumor microenvironment-responsive degradable MnO2 nanosheet, and a mesoporous ZnGa2O4:Cr3+, Sn4+ near-infrared persistent luminescence (NIR-PL) nanosphere (mZGOCS). In our design, mZGOCS@MnO2-P5 enables primarily targeting of the EBV-specific oncoprotein LMP1 (an EBV-encoded transmembrane protein) via the LMP1 targeting motif within P5. Once internalized into cells, the MnO2 nanosheet would be degraded in the acidic and reducing tumor microenvironment, simultaneously releasing P5 and recovering the NIR-PL of ZnGa2O4:Cr3+, Sn4+ initially quenched by the MnO2 nanosheet, thereby providing an autofluorescence interference-free NIR-PL imaging signal for monitoring the delivery efficacy of P5. The released P5 can secondarily target EBNA1 via the EBNA1 binding motif, blocking its function and thus inhibiting the growth of EBV-positive tumors. The feasibility of our developed hierarchical targeting theranostic nanosystem is well demonstrated both in vitro and in vivo, highlighting the huge translational potential of mZGOCS@MnO2-P5 in EBV-associated cancer therapy.

Persistent luminescence (PersL) is widely used for near infrared (NIR-I, 650-950nm) imaging as they allow getting images without background. Bio-imaging in the second shortwave-infrared region SWIR-II (NIR-II, 1000-1400nm) is less widespread but is growing as it offers the advantages of low photon scattering, increased in vivo penetration depth, and improved imaging clarity. In this work, the preparation and the complete optical properties of a new material is reported, Zn1.33Ga1.33Ni0.005Cr0.005Sn0.33O3.995 (ZGSO:Cr3+, Ni2+) able of emitting in both deep-red/NIR-I and SWIR (NIR-II) and shows its potential in bioimaging. ZGSO:Cr3+, Ni2+ can be excited using different sources such as X-rays, UV, and visible light to emit persistent signals in dual biological windows (dual-BW). By integrating an energy transfer process from Cr3+ to Ni2+ within this newly synthesized material, the influence of co-dopants on signal intensity and emission wavelengths is sought to explore. PersL at ≈700nm (NIR-I) and ≈1300nm (NIR-II) have been tested in preliminary bioimaging experiments using different protocols, allowing signal detection with good spatial resolution and depth sensitivity. The dual-BW PersL imaging strategy expands the toolbox for highly accurate analysis and has, for the first time, allowed access to accurately high-resolution sensing, and tracing.

Background & aimDietary shifts replacing animal protein (AP) with plant protein (PP) sources have been associated with lowering cardiometabolic risk (CMR), but underlying mechanisms are poorly characterized. This nutritional intervention aims to characterize the metabolic changes induced by diets containing different proportions of AP and PP sources in males at CMR. DesignThis study is a 4-week, crossover, randomized, controlled-feeding trial in which 19 males with CMR followed two diets providing either 36% for the control diet (CON-D) or 64% for the flexitarian diet (FLEX-D) of total protein intake from PP sources. Plasma nontargeted metabolomes (LC-MS method) were measured in the fasted state and after a high-fat challenge meal at the end of each intervention arm. Lipogenesis and protein synthesis fluxes, flow-mediated dilatation (FMD) and gluco-lipidic responses were assessed after the challenge meal. Data were analyzed with mixed models, and univariate and multivariate models for metabolomics data. ResultsIn both arms CMR improved with time, with decreased body weight (-0.9%), insulin resistant (-34%, HOMA-IR, Homeostatic Model Assessment for Insulin Resistance) and low-density lipoproteins (LDL)-cholesterol (-11%). Diet had no effect on FMD or metabolic fluxes, but a trend was observed for a stronger decrease in HOMA-IR and lower postprandial glucose after FLEX-D vs CON-D. The abundance of 21 and 37 metabolites differed between diets at fasted and fed states, respectively, including food intake biomarkers of AP (methylhistidine, eicosapentaenoic acid, hydroxyprolines) and PP sources (trigonelline, N-acetyl-ornithine). In fasted or fed states, indole acrylic acid and indole propionic acid, both products of tryptophan catabolism, were higher after FLEX-D vs CON-D, while the indispensable amino acids-related metabolites alpha-aminoadipic acid, hydroxymethylbutyric acids and propionylcarnitine were lower. In the postprandial state only, the ω-oxidation products dodecanedioic, tetradecanedioic and hexadecanedioic acids were higher after FLEX-D vs CON-D. ConclusionsDespite little changes in risk factors after 4 wk, this study evidenced subtle metabolic adaptations in amino acids and lipid metabolism and gut microbiota activity occurring after higher PP source intake that may be beneficial to CMR. ClinicalTrials.gov study identifierNCT04236518 Clinical Trial RegistryNCT04236518 on ClinicalTrials.gov