•Simultaneous measurement of eicosanoids and docosanoids by HPLC–MS/MS.•Method for quantification of 24 pro-inflammatory and pro-resolving lipid mediators.•Rapid and robust method.•Method validation ...for application in cellular systems, fluids and tissues.
Lipid autacoids derived from n-3/n-6 polyunsaturated fatty acids (PUFA) are some of the earliest signals triggered by an inflammatory reaction. They are acting also as essential regulators of numerous biological processes in physiological conditions. With regards to their importance, a robust and rapid procedure to quantify a large variety of PUFA metabolites, applicable to diverse biological components needed to be formulated. We have developed a simple methodology using liquid chromatography–tandem mass spectrometry allowing quantification of low-level of PUFA metabolites including bioactive mediators, inactive products and pathway biomarkers. Solid phase extraction was used for samples preparation with an extraction yield of 80% ranging from 65% to 98%. The method was optimized to obtain a rapid (8.5min) and accurate separation of 26 molecules, with a very high sensitivity of detection and analysis (0.6–155pg). When applied to biological samples, the method enabled characterization of eicosanoids and docosanoids production in epithelial cells or foam macrophages stimulated with LPS, in biological fluids and tissues from mouse models of peritonitis or infectious colitis. Our results demonstrate that this new method can be used in cultured cells, in fluids and in colonic tissues to quantify pro-inflammatory and pro-resolving PUFA metabolites mediators.
Elafin, a natural protease inhibitor expressed in healthy intestinal mucosa, has pleiotropic anti-inflammatory properties in vitro and in animal models. We found that mucosal expression of Elafin is ...diminished in patients with inflammatory bowel disease (IBD). This defect is associated with increased elastolytic activity (elastase-like proteolysis) in colon tissue. We engineered two food-grade strains of lactic acid bacteria (LAB) to express and deliver Elafin to the site of inflammation in the colon to assess the potential therapeutic benefits of the Elafin-expressing LAB. In mouse models of acute and chronic colitis, oral administration of Elafin-expressing LAB decreased elastolytic activity and inflammation and restored intestinal homeostasis. Furthermore, when cultures of human intestinal epithelial cells were treated with LAB secreting Elafin, the inflamed epithelium was protected from increased intestinal permeability and from the release of cytokines and chemokines, both of which are characteristic of intestinal dysfunction associated with IBD. Together, these results suggest that oral delivery of LAB secreting Elafin may be useful for treating IBD in humans.
Proteolytic homeostasis is important at mucosal surfaces, but its actors and their precise role in physiology are poorly understood. Here we report that healthy human and mouse colon epithelia are a ...major source of active thrombin. We show that mucosal thrombin is directly regulated by the presence of commensal microbiota. Specific inhibition of luminal thrombin activity causes macroscopic and microscopic damage as well as transcriptomic alterations of genes involved in host-microbiota interactions. Further, luminal thrombin inhibition impairs the spatial segregation of microbiota biofilms, allowing bacteria to invade the mucus layer and to translocate across the epithelium. Thrombin cleaves the biofilm matrix of reconstituted mucosa-associated human microbiota. Our results indicate that thrombin constrains biofilms at the intestinal mucosa. Further work is needed to test whether thrombin plays similar roles in other mucosal surfaces, given that lung, bladder and skin epithelia also express thrombin.
Background & Aims Ligand-gated calcium channels have been reported to be involved in the pathogenesis of inflammatory bowel disease. One family member, transient receptor potential vanilloid 4 ...(TRPV4), is activated by arachidonic acid derivatives that might be released on inflammation, yet its role in gastrointestinal inflammation has not been characterized. We investigated whether TRPV4 activation participates in intestinal inflammation and its expression and functions in the gastrointestinal tract. Methods TRPV4 expression was studied in human colon samples, human intestinal epithelial cell lines (Caco-2 and T84), and inflamed colons of mice. Calcium mobilization and cytokine release were analyzed in intestinal epithelial cells exposed to the selective TRPV4 agonist 4α-phorbol-12,13-didecanoate (4αPDD). Mice were killed 3, 6, or 24 hours after intracolonic administration of 4αPDD; inflammatory parameters were measured in their colon tissues, and paracellular colonic permeability was measured by the passage of51 Cr-EDTA from the colon lumen to the blood. Results High levels of TRPV4 were detected in Caco-2 cells and in epithelial cells of human colon tissue samples; its expression was up-regulated in colons from inflamed mice compared with noninflamed control mice. Administration of 4αPDD to Caco-2 and T84 cells caused a dose-dependent increase in intracellular calcium concentration and chemokine release. In mice, intracolonic administration of 4αPDD caused colitis to develop 3 to 6 hours later; inflammation resolved by 24 hours. Increased colonic permeability was observed in vivo 3 hours after intracolonic administration of 4αPDD. Conclusions TRPV4 is expressed and functional in intestinal epithelial cells; its activation in the gastrointestinal tract causes increases in intracellular calcium concentrations, chemokine release, and colitis.
Imbalance between proteases and their inhibitors plays a crucial role in the development of Inflammatory Bowel Diseases (IBD). Increased elastolytic activity is observed in the colon of patients ...suffering from IBD. Here, we aimed at identifying the players involved in elastolytic hyperactivity associated with IBD and their contribution to the disease. We revealed that epithelial cells are a major source of elastolytic activity in healthy human colonic tissues and this activity is greatly increased in IBD patients, both in diseased and distant sites of inflammation. This study identified a previously unrevealed production of elastase 2A (ELA2A) by colonic epithelial cells, which was enhanced in IBD patients. We demonstrated that ELA2A hyperactivity is sufficient to lead to a leaky epithelial barrier. Epithelial ELA2A hyperactivity also modified the cytokine gene expression profile with an increase of pro-inflammatory cytokine transcripts, while reducing the expression of pro-resolving and repair factor genes. ELA2A thus appears as a novel actor produced by intestinal epithelial cells, which can drive inflammation and loss of barrier function, two essentials pathophysiological hallmarks of IBD. Targeting ELA2A hyperactivity should thus be considered as a potential target for IBD treatment.
Given the anti-inflammatory effects of insulin in human and animal studies done in vivo and given the signaling pathways in common between insulin and the protease-activated receptor 2 (PAR(2)), a G ...protein-coupled receptor, we hypothesized that insulin would have an impact on the inflammatory actions of PAR(2). We found that low doses or concentrations of insulin in the subnanomolar range reduced PAR(2)-induced inflammation in a murine paw edema model, attenuated PAR(2)-induced leukocyte trafficking in mouse intestinal venules, and reduced PAR(2) calcium signaling in cultured dorsal root ganglion neurons and endothelial cells. This effect of insulin to attenuate PAR(2)-mediated inflammation was reversed when cells were preincubated with LY294002 (a PI3K inhibitor) and GF 109203X (a pan-protein kinase C inhibitor). The enhanced inflammatory effect of PAR(2) observed in vivo in an insulin-deficient murine type 1 diabetes model was attenuated by the local administration of insulin at the inflammatory site. Our data point to an anti-inflammatory action of insulin that targets the acute innate inflammatory response triggered by PAR(2).
The gut-brain axis is considered as a major regulatory checkpoint in the control of glucose homeostasis. The detection of nutrients and/or hormones in the duodenum informs the hypothalamus of the ...host's nutritional state. This process may occur via hypothalamic neurons modulating central release of nitric oxide (NO), which in turn controls glucose entry into tissues. The enteric nervous system (ENS) modulates intestinal contractions in response to various stimuli, but the importance of this interaction in the control of glucose homeostasis via the brain is unknown. We studied whether apelin, a bioactive peptide present in the gut, regulates ENS-evoked contractions, thereby identifying a new physiological partner in the control of glucose utilisation via the hypothalamus.
We measured the effect of apelin on electrical and mechanical duodenal responses via telemetry probes and isotonic sensors in normal and obese/diabetic mice. Changes in hypothalamic NO release, in response to duodenal contraction modulated by apelin, were evaluated in real time with specific amperometric probes. Glucose utilisation in tissues was measured with orally administrated radiolabeled glucose.
In normal and obese/diabetic mice, glucose utilisation is improved by the decrease of ENS/contraction activities in response to apelin, which generates an increase in hypothalamic NO release. As a consequence, glucose entry is significantly increased in the muscle.
Here, we identify a novel mode of communication between the intestine and the hypothalamus that controls glucose utilisation. Moreover, our data identified oral apelin administration as a novel potential target to treat metabolic disorders.
Abstract Background Currently, treatment options for patients with advanced melanoma who experience failed immunotherapy or targeted therapy are lacking. Recent studies suggest the antitumor activity ...of combined pembrolizumab and lenvatinib in patients with advanced melanoma progressing on immunotherapy. Herein, we report the clinical outcomes of combined lenvatinib and a programmed cell death protein-1 inhibitor (PD-1) in this population. Materials and Methods This French multicenter real-world study was conducted between September 2020 and July 2023. The primary endpoint was the objective response rate (ORR) according to the Response Evaluation Criteria in Solid Tumours (version 1.1). Secondary variables were treatment-related adverse events (TRAEs), progression-free survival (PFS), overall survival (OS), and duration of response (DOR). Results Of the 67 patients included (median age, 69 years; median follow-up, 5.0 months), 85% had stage IV-M1c or M1d disease. The overall ORR was 28.4% (95% CI, 18%-41%), including 3 complete (4.5%) and 16 partial (23.9%) responses. Median DOR was 3.1 (interquartile range, 1.3-4.3) months. Median PFS and OS were 3.1 (95% CI, 2.5-3.7) and 9.8 (95% CI, 5.6-13.9) months, respectively. Grades 3-5 TRAEs occurred in 16 (24%) patients; common TRAEs were fatigue (43.3%), nausea/vomiting (26.8%), diarrhea (20.9%), and hypertension (20.9%). No treatment-related deaths occurred. Conclusion Our real-world study demonstrates an interesting response rate and acceptable safety profile in a population with poor prognostic factors. Our data support this treatment option for refractory melanoma, as it is not approved by the Food and Drug Administration or European Medicines Agency, and highlight the need for new strategies.
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