Agonist of RORA Attenuates Nonalcoholic Fatty Liver Progression in Mice via Up-regulation of MicroRNA 122

BACKGROUND & AIMS

Development of nonalcoholic steatohepatitis (NASH) is associated with reductions in hepatic microRNA122 (MIR122); the RAR related orphan receptor A (RORA) promotes expression of MIR122. Increasing expression of RORA in livers of mice increases expression of MIR122 and reduces lipotoxicity. We investigated the effects of a RORA agonist in mouse models of NASH.

METHODS

We screened a chemical library to identify agonists of RORA and tested their effects on a human hepatocellular carcinoma cell line (Huh7). C57BL/6 mice were fed a chow or high-fat diet (HFD) for 4 weeks to induce fatty liver. Mice were given hydrodynamic tail vein injections of a MIR122 antagonist (antagomiR-122) or a control antagomiR once each week for 3 weeks while still on the HFD or chow diet, or intraperitoneal injections of the RORA agonist RS-2982 or vehicle, twice each week for 3 weeks. Livers, gonad white adipose, and skeletal muscle were collected and analyzed by reverse-transcription polymerase chain reaction, histology, and immunohistochemistry. A separate group of mice were fed an atherogenic diet, with or without injections of RS-2982 for 3 weeks; livers were analyzed by immunohistochemistry, and plasma was analyzed for levels of aminotransferases. We analyzed data from liver tissues from patients with NASH included in the RNA-sequencing databases GSE33814 and GSE89632.

RESULTS

Injection of mice with antagomiR-122 significantly reduced levels of MIR122 in plasma, liver, and white adipose tissue; in mice on an HFD, antagomiR-122 injections increased fat droplets and total triglyceride content in liver and reduced β-oxidation and energy expenditure, resulting in significantly more weight gain than in mice given the control microRNA. We identified RS-2982 as an agonist of RORA and found it to increase expression of MIR122 promoter activity in Huh7 cells. In mice fed an HFD or atherogenic diet, injections of RS-2982 increased hepatic levels of MIR122 precursors and reduced hepatic synthesis of triglycerides by reducing expression of biosynthesis enzymes. In these mice, RS-2982 significantly reduced hepatic lipotoxicity, reduced liver fibrosis, increased insulin resistance, and reduced body weight compared with mice injected with vehicle. Patients who underwent cardiovascular surgery had increased levels of plasma MIR122 compared to its levels before surgery; increased expression of plasma MIR122 was associated with increased levels of plasma free fatty acids and levels of RORA.

CONCLUSIONS

We identified the compound RS-2982 as an agonist of RORA that increases expression of MIR122 in cell lines and livers of mice. Mice fed an HFD or atherogenic diet given injections of RS-2982 had reduced hepatic lipotoxicity, liver fibrosis, and body weight compared with mice given the vehicle. Agonists of RORA might be developed for treatment of NASH.

The lipidome of endometrial fluid differs between implantative and non-implantative IVF cycles

OBJECTIVE

To characterize the most relevant changes in the lipidome of endometrial fluid aspirate (EFA) in non-implantative cycles.

DESIGN

Lipidomics in a prospective cohort study.

SETTINGS

Reproductive unit of a university hospital.

PATIENTS

Twenty-nine women undergoing an IVF cycle. Fifteen achieved pregnancy and 14 did not.

INTERVENTION

Endometrial fluid aspiration immediately before performing embryo transfer.

MAIN OUTCOME MEASURES

Clinical pregnancy rate and lipidomic profiles obtained on an ultra-high performance liquid chromatography coupled to time-of-flight mass spectrometry (UHPLC-ToF-MS)-based analytical platform.

RESULTS

The comparative analysis of the lipidomic patterns of endometrial fluid in implantative and non-implantative IVF cycles revealed eight altered metabolites: seven glycerophospholipids and an omega-6 polyunsaturated fatty acid. Then, women with a non-implantative cycle were accurately classified with a support vector machine algorithm including these eight lipid metabolites. The diagnostic performances of the algorithm showed an area under the receiver operating characteristic curve, sensitivity, specificity, and accuracy of 0.893 ± 0.07, 85.7%, 80.0%, and 82.8%, respectively.

CONCLUSION

A predictive lipidomic signature linked to the implantative status of the endometrial fluid has been found.

Targeted UPLC-MS Metabolic Analysis of Human Faeces Reveals Novel Low-Invasive Candidate Markers for Colorectal Cancer

Low invasive tests with high sensitivity for colorectal cancer and advanced precancerous lesions will increase adherence rates, and improve clinical outcomes. We have performed an ultra-performance liquid chromatography/time-of-flight mass spectrometry (UPLC-(TOF) MS)-based metabolomics study to identify faecal biomarkers for the detection of patients with advanced neoplasia. A cohort of 80 patients with advanced neoplasia (40 advanced adenomas and 40 colorectal cancers) and 49 healthy subjects were analysed in the study. We evaluated the faecal levels of 105 metabolites including glycerolipids, glycerophospholipids, sterol lipids and sphingolipids. We found 18 metabolites that were significantly altered in patients with advanced neoplasia compared to controls. The combinations of seven metabolites including ChoE(18:1), ChoE(18:2), ChoE(20:4), PE(16:0/18:1), SM(d18:1/23:0), SM(42:3) and TG(54:1), discriminated advanced neoplasia patients from healthy controls. These seven metabolites were employed to construct a predictive model that provides an area under the curve (AUC) median value of 0.821. The inclusion of faecal haemoglobin concentration in the metabolomics signature improved the predictive model to an AUC of 0.885. In silico gene expression analysis of tumour tissue supports our results and puts the differentially expressed metabolites into biological context, showing that glycerolipids and sphingolipids metabolism and GPI-anchor biosynthesis pathways may play a role in tumour progression.

Use of a metabolomic approach to non-invasively diagnose non-alcoholic fatty liver disease in patients with type 2 diabetes mellitus

AIMS

To assess the utility of existing metabolomics scores to classify liver disease in patients with type 2 diabetes mellitus (T2DM).

MATERIALS AND METHODS

A total of 220 patients with T2DM were recruited. Patients underwent routine laboratory tests, liver proton magnetic resonance spectroscopy (¹ H-MRS), a 75-g oral glucose tolerance test, and liver biopsy if ¹ H-MRS findings indicated non-alcoholic fatty liver disease. A serum sample was blindly provided to OWL Metabolomics on which to run the OWLiver Care and OWLiver tests.

RESULTS

When compared with liver biopsy, the OWLiver Care and OWLiver tests had a suboptimal performance in patients with T2DM (areas under the receiver-operating characteristic [AUROC] curve both <0.70). Given the discordance of these results in this heterogeneous, multiethnic cohort compared with those of a previous report in predominantly white patients without diabetes, we examined the influence of age, ethnicity and other variables on test performance. A specific subset of patients was selected to mirror the characteristics of the population used for the development of this model (ie, white patients without T2DM). Among white patients with good glycaemic control (glycated haemoglobin <53mmol/mol [or <7%]) and without cirrhosis, the AUROC curve was significantly improved (0.79 [CI 95%: 0.68-0.90]). Among white patients with lower insulin resistance (homeostatic model assessment of insulin resistance <3) and without cirrhosis, the AUROC was even higher: 0.87 (CI 95%: 0.76-0.97).

CONCLUSIONS

There is a great need to develop non-invasive approaches to diagnose non-alcoholic steatohepatitis in patients with T2DM; models originally developed for patients without diabetes cannot be directly applied to patients with T2DM.

Solute carrier family 2 member 1 is involved in the development of nonalcoholic fatty liver disease

Susceptibility to develop nonalcoholic fatty liver disease (NAFLD) has genetic bases, but the associated variants are uncertain. The aim of the present study was to identify genetic variants that could help to prognose and further understand the genetics and development of NAFLD. Allele frequencies of 3,072 single-nucleotide polymorphisms (SNPs) in 92 genes were characterized in 69 NAFLD patients and 217 healthy individuals. The markers that showed significant allele-frequency differences in the pilot groups were subsequently studied in 451 NAFLD patients and 304 healthy controls. Besides this, 4,414 type 2 diabetes mellitus (T2DM) cases and 4,567 controls were genotyped. Liver expression of the associated gene was measured and the effect of its potential role was studied by silencing the gene in vitro. Whole genome expression, oxidative stress (OS), and the consequences of oleic acid (OA)-enriched medium on lipid accumulation in siSLC2A1-THLE2 cells were studied by gene-expression analysis, dihydroethidium staining, BODIPY, and quantification of intracellular triglyceride content, respectively. Several SNPs of SLC2A1 (solute carrier family 2 [facilitated glucose transporter] member 1) showed association with NAFLD, but not with T2DM, being the haplotype containing the minor allele of SLC2A1 sequence related to the susceptibility to develop NAFLD. Gene-expression analysis demonstrated a significant down-regulation of SLC2A1 in NAFLD livers. Enrichment functional analyses of transcriptome profiles drove us to demonstrate that in vitro silencing of SLC2A1 induces an increased OS activity and a higher lipid accumulation under OA treatment.

CONCLUSIONS

Genetic variants of SLC2A1 are associated with NAFLD, and in vitro down-regulation of this gene promotes lipid accumulation. Moreover, the oxidative response detected in siSLC2A1-THLE2 cells corroborated the antioxidant properties previously related to this gene and linked the most representative clinical characteristics of NAFLD patients: oxidative injury and increased lipid storage.