Effects of IL-15 and its specific inhibitor, the mutant IL-15/FCγ2Aprotein, on bone turnover: new factors in osteo-inmmune context

L'IL-15 et l'IL-21 étant des cytokines jouant un rôle clé dans la pathogénie de maladies inflammatoires et auto-immunes, l'inhibition des voies de signalisation de ces deux cytokines sont à explorer comme nouveaux outils thérapeutiques. De ce fait, nous avons étudié l'IL-15 et l'IL-21 ainsi que de leurs antagonistes dans un modèle murins de l'ostéoporose. Nous avons démontré que l'antagoniste de l'IL-15 peut raisonnablement représenter un nouvel outil thérapeutique aussi bien dans le cas de l'ostéoporose post-ménopausique que dans une l'ostéoporose survenant à la suite d'une maladie auto-immune. L'antagoniste de l'IL-21 inhibe complètement la voie de signalisation de l'IL-21. Nos résultats confirment que l'IL-21 est une cytokine unique, capable de maintenir les lymphocytes T à l'état naïf, tout en préservant leurs propriétés effectrices et mémoires. Tel que l'antagoniste de l'IL-15, l'antagoniste spécifique de l'IL-21 peut être utilisé in vivo et in vitro afin d'étudier des modèles murins de maladie auto-immune

Enoxaparin Attenuates Mouse Colon Cancer Liver Metastases by Inhibiting Heparanase and Interferon-γ-inducible Chemokines

Low-molecular-weight heparin (LMWH) has been suggested to reduce the risk of cancer progression in both preclinical and clinical studies but the underlying mechanisms remain poorly explored. The aim of the study was to investigate the anti-metastatic role of enoxaparin, a clinically-used LMWH, in a murine model of colon cancer and to explore its underlying mechanisms

In vivo investigations on anti-fibrotic potential of proteasome inhibition in lung and skin fibrosis

In systemic sclerosis (SSc), a disease characterized by fibrosis of the skin and internal organs, the occurrence of interstitial lung disease is responsible for high morbidity and mortality. We previously demonstrated that proteasome inhibitors (PI) show anti-fibrotic properties in vitro by reducing collagen production and favoring collagen degradation in a c-jun N-terminal kinase (JNK)-dependent manner in human fibroblasts. Therefore, we tested whether PI could control fibrosis development in bleomycin-induced lung injury, which is preceded by massive inflammation. We extended the study to test PI in TSK-1/+ mice, where skin fibrosis develops in the absence of overt inflammation. C57Bl/6 mice received bleomycin intratracheally and were treated or not with PI. Lung inflammation and fibrosis were assessed by histology and quantification of hydroxyproline content, type I collagen mRNA, and TGF-beta at Days 7, 15, and 21, respectively. Histology was used to detect skin fibrosis in TSK-1/+mice. The chymotryptic activity of 20S proteasome was assessed in mice blood. JNK and Smad2 phosphorylation were evaluated by Western blot on lung protein extracts. PI reduced collagen mRNA levels in murine lung fibroblasts, without affecting their viability in vitro. In addition, PI inhibited the chymotryptic activity of proteasome and enhanced JNK and TGF-beta signaling in vivo. PI failed to prevent bleomycin-induced lung inflammation and fibrosis and to attenuate skin fibrosis in TSK-1/+mice. In conclusion, our results provide direct evidence that, despite promising in vitro results, proteasome blockade may not be a strategy easily applicable to control fibrosis development in diseases such as lung fibrosis and scleroderma

Metataxonomic and Metabolic Impact of Fecal Microbiota Transplantation From Patients With Pancreatic Cancer Into Germ-Free Mice: A Pilot Study.

Background Body weight (BW) loss is prevalent in patients with pancreatic cancer (PC). Gut microbiota affects BW and is known to directly shape the host immune responses and antitumor immunity. This pilot study evaluated the link between gut microbiota, metabolic parameters and inflammatory/immune parameters, through the fecal material transplantation (FMT) of PC patients and healthy volunteers into germ-free (GF) mice. Methods We transplanted the feces from five PC patients and five age- and gender-matched healthy volunteers into two GF mice each. Mouse BW and energy intake were measured every 1-5 days, oral glucose on day 21, insulin tolerance on day 26, fecal bacterial taxonomic profile by 16S rRNA gene sequencing on day 5, 10, 15 and 30, and gut-associated lymphoid tissue T cells, plasma cytokines and weights of fat and muscle mass at sacrifice (day 34). Results are presented as mean ± SD. The continuous parameters of mice groups were compared by linear univariate regressions, and their bacterial communities by Principal Coordinates Analysis (PCoA), Bray-Curtis similarity and ANCOM test. Results Recipients of feces from PC patients and healthy volunteers had similar BW gain and food intake. Visceral fat was lower in recipients of feces from PC patients than from healthy individuals (0.72 ± 0.17 vs. 0.92 ± 0.14 g; coeff -0.19, 95% CI -0.38, -0.02, p=0.035). The other non-metataxonomic parameters did not differ between groups. In PCoA, microbiota from PC patients clustered apart from those of healthy volunteers and the same pattern was observed in transplanted mice. The proportions of Clostridium bolteae, Clostridium scindens, Clostridium_g24_unclassified and Phascolarctobacterium faecium were higher, while those of Alistipes obesi, Lachnospiraceae PAC000196_s and Coriobacteriaceae_unclassified species were lower in PC patients and in mice transplanted with the feces from these patients. Conclusion In this pilot study, FMT from PC patients was associated with a decrease in visceral fat as compared to FMT from healthy individuals. Some of the differences in fecal microbiota between PC and control samples are common to humans and mice. Further research is required to confirm that feces contain elements involved in metabolic and immune alterations