Nuclear Receptors Regulate Intestinal Inflammation in the Context of IBD

Gastrointestinal (GI) homeostasis is strongly dependent on nuclear receptor (NR) functions. They play a variety of roles ranging from nutrient uptake, sensing of microbial metabolites, regulation of epithelial intestinal cell integrity to shaping of the intestinal immune cell repertoire. Several NRs are associated with GI pathologies; therefore, systematic analysis of NR biology, the underlying molecular mechanisms, and regulation of target genes can be expected to help greatly in uncovering the course of GI diseases. Recently, an increasing number of NRs has been validated as potential drug targets for therapeutic intervention in patients with inflammatory bowel disease (IBD). Besides the classical glucocorticoids, especially PPARγ, VDR, or PXR-selective ligands are currently being tested with promising results in clinical IBD trials. Also, several pre-clinical animal studies are being performed with NRs. This review focuses on the complex biology of NRs and their context-dependent anti- or pro-inflammatory activities in the regulation of gastrointestinal barrier with special attention to NRs already pharmacologically targeted in clinic and pre-clinical IBD treatment regimens

Up-regulation of the anti-inflammatory adipokine adiponectin in acute liver failure in mice

BACKGROUND/AIMS: Recent reports suggest that the adipose tissue and adipokines are potent modulators of inflammation. However, there is only scarce knowledge on the functional role and regulation of endogenous adiponectin in non-fat tissues such as the liver under conditions of acute inflammation. METHODS: In the present study, we investigated adiponectin expression in healthy murine liver tissue and under inflammatory conditions in vivo. RESULTS: Adiponectin mRNA was readily detectable in healthy liver tissue and further increased in ConA-mediated acute liver failure. Adiponectin protein expression was mainly found in hepatic endothelial cells. In vitro adiponectin mRNA expression was detectable in several cell types, including primary hepatic sinusoidal endothelial cells, stellate cells, and macrophages. Mice pretreated with adiponectin before ConA administration developed reduced hepatic injury as shown by decreased release of transaminases and reduced hepatocellular apoptotis. Of note, TNF-alpha levels were not affected by adiponectin, whereas IL-10 production was increased. Neutralisation of IL-10 diminished the protective effect of adiponectin. CONCLUSIONS: Adiponectin expression is up-regulated in ConA-mediated acute liver failure. Therefore, adiponectin might play a role in the control and limitation of inflammation in the liver. Moreover, our data suggest a role for IL-10 in adiponectin-mediated hepatoprotection

Adipokines and inflammation: is it a question of weight?

Obesity has reached epidemic proportions in the Western society and is increasing in the developing world. It is considered as one of the major contributors to the global burden of disability and chronic diseases, including autoimmune, inflammatory and degenerative diseases. Research conducted on obesity and its complications over the last two decades has transformed the outdated concept of white adipose tissue (WAT) merely serving as an energy depot. WAT is now recognized as an active and inflammatory organ capable of producing a wide variety of factors known as adipokines. These molecules participate through endocrine, paracrine, autocrine, or juxtacrine cross-talk mechanisms in a great variety of physiological or pathophysiological processes, regulating food intake, insulin sensitivity, immunity, and inflammation. Although initially restricted to metabolic activities (regulation of glucose and lipid metabolism), adipokines currently represent a new family of proteins that can be considered key players in the complex network of soluble mediators involved in the pathophysiology of immune/inflammatory diseases. However, the complexity of the adipokine network in the pathogenesis and progression of inflammatory diseases has posed, since the beginning, the important question of whether it may be possible to target the mechanism(s) by which adipokines contribute to disease selectively without suppressing their physiological functions. Here we explore in depth the most recent findings concerning the involvement of adipokines in inflammation and immune responses, in particular in rheumatic, inflammatory and degenerative diseases. We also highlight several possible strategies for therapeutic development and propose that adipokines and their signalling pathways may represent innovative therapeutic strategies for inflammatory disorders.ACKNOWLEDGMENTS: OG and FL are Staff Personnel of Xunta de Galicia (Servizo Galego de Saude, SERGAS) through a research-staff stabilization contract (ISCIII/SERGAS). VF is a “Sara Borrell” Researcher funded by ISCIII and FEDER. RG is a “Miguel Servet” Researcher funded by Instituto de Salud Carlos III (ISCIII) and FEDER. OG, MAGG and RG are members of RETICS Programme, RD16/0012/0014 (RIER: Red de Investigación en Inflamación y Enfermedades Reumáticas) via Instituto de Salud Carlos III (ISCIII) and FEDER. FL is a member of CIBERCV (Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares). The work of OG (PIE13/00024 and PI14/00016, PI17/00409), FL (PI15/00681 and CB16/11/00226) and RG (PI16/01870 and CP15/00007) was funded by Instituto de Salud Carlos III and FEDER. OG is a beneficiary of a project funded by Research Executive Agency of the European Union in the framework of MSCA-RISE Action of the H2020 Programme (Project number 734899). AM has received funding from the European Commission Framework 7 programme (EU FP7; HEALTH.2012.2.4.5-2, project number 305815; Novel Diagnostics and Biomarkers for Early Identification of Chronic Inflammatory Joint Diseases) plus generous support from the Innovative Medicines Initiative Joint Undertaking under grant agreement No. 115770, resources of which are composed of financial contribution from the European Union’s Seventh Framework programme (FP7/2007-2013) and EFPIA companies’ in kind contribution. The funders had no role in study design, data collection, and analysis, decision to publish, or preparation of the manuscript

Modelling the benefits of an optimised treatment strategy for 5-ASA in mild-to-moderate ulcerative colitis.

peer reviewedOBJECTIVES: 5-aminosalicylate (mesalazine; 5-ASA) is an established first-line treatment for mild-to-moderate ulcerative colitis (UC). This study aimed to model the benefits of optimising 5-ASA therapy. METHODS: A decision tree model followed 10 000 newly diagnosed patients with mild-to-moderately active UC through induction and 1 year of maintenance treatment. Optimised treatment (maximising dose of 5-ASA and use of combined oral and rectal therapy before treatment escalation) was compared with standard treatment (standard doses of 5-ASA without optimisation). Modelled data were derived from published meta-analyses. The primary outcomes were patient numbers achieving and maintaining remission, with an analysis of treatment costs for each strategy conducted as a secondary outcome (using UK reference costs). RESULTS: During induction, there was a 39% increase in patients achieving remission through the optimised pathway without requiring systemic steroids and/or biologics (6565 vs 4725 for standard). Potential steroidal/biological adverse events avoided included: seven venous thromboembolisms and eight serious infections. Out of the 6565 patients entering maintenance following successful induction on 5-ASA, there was a 21% reduction in relapses when optimised (1830 vs 2311 for standard). This translated into 297 patients avoiding further systemic steroids and 214 biologics. Optimisation led to an average net saving of £272 per patient entering the model for the induction and maintenance of remission over 1 year. CONCLUSION: Modelling suggests that optimising 5-ASA therapy (both the inclusion of rectal 5-ASA into a combined oral and rectal regimen and maximisation of 5-ASA dose) has clinical and cost benefits that supports wider adoption in clinical practice

The impact of clinical experience on decision-making regarding the treatment and management of mild-to-moderate ulcerative colitis.

peer reviewe

Pharmacological Inhibition of Nicotinamide Phosphoribosyltransferase/Visfatin Enzymatic Activity Identifies a New Inflammatory Pathway Linked to NAD

Nicotinamide phosphoribosyltransferase (NAMPT), also known as visfatin, is the rate-limiting enzyme in the salvage pathway of NAD biosynthesis from nicotinamide. Since its expression is upregulated during inflammation, NAMPT represents a novel clinical biomarker in acute lung injury, rheumatoid arthritis, and Crohn's disease. However, its role in disease progression remains unknown. We report here that NAMPT is a key player in inflammatory arthritis. Increased expression of NAMPT was confirmed in mice with collagen-induced arthritis, both in serum and in the arthritic paw. Importantly, a specific competitive inhibitor of NAMPT effectively reduced arthritis severity with comparable activity to etanercept, and decreased pro-inflammatory cytokine secretion in affected joints. Moreover, NAMPT inhibition reduced intracellular NAD concentration in inflammatory cells and circulating TNFα levels during endotoxemia in mice. In vitro pharmacological inhibition of NAMPT reduced the intracellular concentration of NAD and pro-inflammatory cytokine secretion by inflammatory cells. Thus, NAMPT links NAD metabolism to inflammatory cytokine secretion by leukocytes, and its inhibition might therefore have therapeutic efficacy in immune-mediated inflammatory disorders

A gut bacterial signature in blood and liver tissue characterizes cirrhosis and hepatocellular carcinoma

BackgroundHCC is the leading cause of cancer in chronic liver disease. A growing body of experimental mouse models supports the notion that gut-resident and liver-resident microbes control hepatic immune responses and, thereby, crucially contribute to liver tumorigenesis. However, a comprehensive characterization of the intestinal microbiome in fueling the transition from chronic liver disease to HCC in humans is currently missing.MethodsHere, we profiled the fecal, blood, and liver tissue microbiome of patients with HCC by 16S rRNA sequencing and compared profiles to nonmalignant cirrhotic and noncirrhotic NAFLD patients.ResultsWe report a distinct bacterial profile, defined from 16S rRNA gene sequences, with reduced α-and β-diversity in the feces of patients with HCC and cirrhosis compared to NAFLD. Patients with HCC and cirrhosis exhibited an increased proportion of fecal bacterial gene signatures in the blood and liver compared to NAFLD. Differential analysis of the relative abundance of bacterial genera identified an increased abundance of Ruminococcaceae and Bacteroidaceae in blood and liver tissue from both HCC and cirrhosis patients compared to NAFLD. Fecal samples from cirrhosis and HCC patients both showed a reduced abundance for several taxa, including short-chain fatty acid-producing genera, such as Blautia and Agathobacter. Using paired 16S rRNA and transcriptome sequencing, we identified a direct association between gut bacterial genus abundance and host transcriptome response within the liver tissue.ConclusionsOur study indicates perturbations of the intestinal and liver-resident microbiome as a critical determinant of patients with cirrhosis and HCC