Role of hydrogen sulfide in the regulation of respiration, blood flow and bile secretory function of the liver

In acute experiments on laboratory rats, intra-portal administration of L-cysteine (20 mg/kg), the precursor of hydrogen sulfide synthesis, stimulated oxygen consumption of liver by 38.6% and reduced oxygen tension by 37.1%. Activation of tissue respiration occurred due to the strengthening of oxygen-dependent synthetic processes in liver, in particular those associated with mitochondrial enzyme-catalysed bile acid biosynthesis through the acidic pathway. The concentrations of taurocholic acid and mixtures of taurodeoxycholic and taurohenodeoxycholic acids increased by 10.3 and 17.9%, respectively, compared to the initial levels. In addition, the level of free cholesterol was decreased by 33.9% and esterification processes were intensified, as indicated by an increase in the concentration of esterified cholesterol by 22.6% in the bile of rats. The latter was to some extent confirmed by a decrease in the level of free bile acids (by 15.8%) involved in the biosynthesis of cholesterol esters and intensification of tissue respiration in the liver. L-cysteine dilated intrahepatic vessels, resulting in a significant decrease of the systemic blood pressure and blood pressure in the portal vein by 17.6 and 24.5%, respectively. L-cysteine increased the rate of local blood flow in the liver and blood supply by 28.2 and 24.4%, respectively. Blockade of cystathionine-γ-lyase by DL-propargylglycine (11 mg/kg) significantly inhibited the L-cysteine-induced tissue respiration and bile acid biosynthesis in the liver. Administration of DL-propargylglycine resulted in constriction of blood vessels of the liver and, as a consequence, to an increased blood pressure and a decreased blood flow rate in tissue. Our data point to an involvement of hydrogen sulfide in the regulation of liver tissue respiration and bile secretory function.

Identification of Mitochondrial-Related Prognostic Biomarkers Associated With Primary Bile Acid Biosynthesis and Tumor Microenvironment of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the leading causes of tumor-associated deaths worldwide. Despite great progress in early diagnosis and multidisciplinary tumor management, the long-term prognosis of HCC remains poor. Currently, metabolic reprogramming during tumor development is widely observed to support rapid growth and proliferation of cancer cells, and several metabolic targets that could be used as cancer biomarkers have been identified. The liver and mitochondria are the two centers of human metabolism at the whole organism and cellular levels, respectively. Thus, identification of prognostic biomarkers based on mitochondrial-related genes (Mito-RGs)—the coding-genes of proteins located in the mitochondria—that reflect metabolic changes associated with HCC could lead to better interventions for HCC patients. In the present study, we used HCC data from The Cancer Genome Atlas (TCGA) database to construct a classifier containing 10 Mito-RGs (ACOT7, ADPRHL2, ATAD3A, BSG, FAM72A, PDK3, PDSS1, RAD51C, TOMM34, and TRMU) for predicting the prognosis of HCC by using 10-fold Least Absolute Shrinkage and Selection Operation (LASSO) cross-validation Cox regression. Based on the risk score calculated by the classifier, the samples were divided into high- and low-risk groups. Gene set enrichment analysis (GSEA), gene set variation analysis (GSVA), t-distributed stochastic neighbor embedding (t-SNE), and consensus clusterPlus algorithms were used to identify metabolic pathways that were significantly different between the high- and low-risk groups. We further investigated the relationship between metabolic status and infiltration of immune cells into HCC tumor samples by using the Cell-type Identification By Estimating Relative Subsets Of RNA Transcripts (CIBERSORT) algorithm combined with the Tumor Immune Estimation Resource (TIMER) database. Our results showed that the classifier based on Mito-RGs could act as an independent biomarker for predicting survival of HCC patients. Repression of primary bile acid biosynthesis plays a vital role in the development and poor prognosis of HCC, which provides a potential approach to treatment. Our study revealed cross-talk between bile acid and infiltration of tumors by immune cells, which may provide novel insight into immunotherapy of HCC. Furthermore, our research may provide a novel method for HCC metabolic therapy based on modulation of mitochondrial function.

METABOLIC PROFILE IN PLASMA AND CSF OF LEVODOPA-INDUCED DYSKINESIA OF PARKINSON’S DISEASE

Structured AbstractBackgroundThe existence of few biomarkers and the lack of a better understanding of the pathophysiology of levodopa-induced dyskinesia (LID) in Parkinson’s disease (PD) require new approaches, as the metabolomic analysis, for discoveries.ObjectivesWe aimed to identify a metabolic profile associated with LID in patients with PD in an original cohort, and to confirm the results in an external cohort (BioFIND).MethodsIn the original cohort, plasma and CSF were collected from 20 healthy controls, 23 patients with PD without LID, and 24 patients with PD with LID. LC-MS/MS and metabolomics data analysis were used to perform untargeted metabolomics. Untargeted metabolomics data from the BioFIND cohort were analyzed.ResultsWe identified a metabolic profile associated with LID in PD, composed of multiple metabolic pathways. In particular, the dysregulation of glycosphingolipids metabolic pathway was more related to LID and was strongly associated with the severity of dyskinetic movements. Further, bile acid biosynthesis and C21-steroid hormone biosynthesis metabolites simultaneously found in plasma and CSF have distinguished patients with LID from other participants. Levels of cortisol and cortisone were reduced in patients with PD and LID compared to patients with PD without LID. Data from the BioFIND cohort confirmed dysregulation in plasma metabolites from the bile acid biosynthesis and C21-steroid hormone biosynthesis pathways.ConclusionThere is a distinct metabolic profile associated with LID in PD, both in plasma and CSF, which may be associated with the dysregulation of lipid metabolism and neuroinflammation.

Identification of prognostic and metastasis-related alternative splicing signatures in hepatocellular carcinoma

As the most common neoplasm in digestive system, hepatocellular carcinoma (HCC) is one of the most important leading cause of cancer deaths worldwide. Its high-frequency metastasis and relapse rate lead to the poor survival of HCC patients. However, the mechanism of HCC metastasis is still unclear. Alternative splicing events (ASEs) have a great effect in cancer development, progression and metastasis. We downloaded RNA sequencing and seven types of ASEs data of HCC samples, in order to explore the mechanism of ASEs underlying tumorigenesis and metastasis of HCC. The data were taken from the The Cancer Genome Atlas (TCGA) and TCGASpliceSeq databases. Univariate Cox regression analysis was used to determine a total of 3197 overall survival-related ASEs (OS-SEs). And based on five OS-SEs screened by Lasso regression, we constructed a prediction model with the Area Under Curve of 0.765. With a good reliability of the model, the risk score was also proved to be an independent predictor. Among identified 390 candidate SFs, Y-box protein 3 (YBX3) was significantly correlated with OS and metastasis. Among 177 ASEs, ATP-binding cassette subfamily A member 6 (ABCA6)-43162-AT and PLIN5-46808-AT were identified both associated with OS, bone metastasis and co-expressed with SFs. Then we identified primary bile acid biosynthesis as survival-related (KEGG) pathway by Gene Set Variation Analysis (GSVA) and univariate regression analysis, which was correlated with ABCA6-43162-AT and PLIN5-46808-AT. Finally, we proposed that ABCA6-43162-AT and PLIN5-46808-AT may contribute to HCC poor prognosis and metastasis under the regulation of aberrant YBX3 through the pathway of primary bile acid biosynthesis.

THU0405 SERUM METABOLIC PROFILING ANALYSIS OF GOUT PATIENTS BASED ON UHPLC-Q-TOF/MS

Background:Gout is a common kind of inflammatory arthritis with metabolic disorders. The detailed pathogenesis of gout remains largely unknown. Metabolomics has become an important tool in detecting the new pathogenesis and biomarkers. However, few studies have focused on the serum metabolic profiling of gout.Objectives:The study aims to investigate the metabolic profiling of gout patients with ultra-performance liquid chromatograph quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS), and explore the potential pathological mechanisms and biomarkers.Methods:Serum samples from 31 gout patients and 31 healthy controls were analyzed by UPLC-Q-TOF-MS. Principal components analysis (PCA), orthogonal partial least squares-discriminant analysis (OPLS-DA) and Hierarchical clustering analysis were performed to detect different compounds between the two groups. Receiver operating characteristic (ROC) curve analysis and pathway analysis of the different metabolites were conducted.Results:A total of 9192 compounds were detected, of which 138 significantly different compounds were selected, according to the criteria of (Variable importance in projection (VIP)>3,P<0.05). Eventually, 96 reliable metabolites matched the HMDB database were confirmed. ROC curve results showed that the area under the curve (AUC) value of 4-hydroxytriazolam for gout was 0.933 (CI95%: 0.875-0.992), yielding a highest AUC value, with the sensitivity of 83.9% and specificity of 93.5%. The pathway analysis results indicated that the significantly different metabolites were mainly involved in “primary bile acid biosynthesis”, “purine metabolism” and “glycerophospholipid metabolism”.Conclusion:The serum metabolic profiling in gout patients were significantly different from healthy subjects. 4-hydroxytriazolam was the potential biomarkers. Primary bile acid biosynthesis may be a novel metabolic pathway of gout.References:[1]Banoei MM, et al. Metabolomics and Biomarker Discovery in Traumatic Brain Injury. J Neurotrauma, 2018. 35(16): p. 1831-1848.Disclosure of Interests: :None declared

Bile Acid Biosynthesis Avoiding Cholesterol

Bile acids are the end products of cholesterol metabolism secreted into bile. They are essential for the absorption of lipids and lipid soluble compounds from the intestine. Here we have investigated the bile acid content of plasma and urine from patients with a defect in cholesterol biosynthesis, i.e. Smith-Lemli-Opitz syndrome (SLOS), resulting in elevated levels of 7-dehydrocholesterol (7-DHC), an immediate precursor of cholesterol. Using liquid chromatography – mass spectrometry (LC-MS) we have identified a novel pathway of bile acid biosynthesis in SLOS avoiding cholesterol starting with 7-DHC. This pathway also proceeds to a minor extent in healthy individuals. Monitoring of the pathway products could provide a rapid diagnostic for SLOS while elevated levels of pathway intermediates could be responsible for some of the features of the disease. Importantly, intermediates in the pathway are modulators of the activity of Smoothened, an oncoprotein that mediates Hedgehog signalling during embryogenesis and regeneration of postembryonic tissue.