Adrenic acid induces oxidative stress in hepatocytes

miR-218-5p promotes hepatic lipogenesis through targeting Elovl5 in non-alcoholic fatty liver disease

Investigating and identifying pathogenic molecules of non-alcoholic fatty liver disease (NAFLD) has become imperative, which would serve as effective targets in the future. We established high-fat diet (HFD)-induced NAFLD model in mice and palmitic acid (PA)-induced model in mouse AML12 cells. The level of miR-218-5p was examined by qRT-PCR, and Elovl5 was identified as the potential target gene of miR-218-5p. The binding relationship between miR-218-5p and Elovl5 was validated by double luciferase reporter gene assay, and inhibition/overexpression of miR-218-5p in vitro. The functional mechanisms of miR-218-5p/Elovl5 in regulating lipogenesis in NAFLD were investigated in vivo and in vitro through gain- and loss-of-function studies. MiR-218-5p was significantly increased, and Elovl5 was decreased in model group. According to the double luciferase reporter and gene interference experiments in AML12 cells, Elovl5 was a target gene of miR-218-5p and its expression was regulated by miR-218-5p. The SREBP1-mediated lipogenesis signaling pathway regulated by Elovl5 was upregulated in model group. Moreover, silencing of miR-218-5p significantly upregulated Elovl5 expression, and suppressed SREBP1 signaling pathway in PA-induced AML-12 cells. Correspondingly, the cell injury, elevated TC, TG contents and lipid droplet accumulation were ameliorated. Furthermore, the effect of miR-218-5p on lipogenesis in vitro and in vivo was obstructed by si-Elovl5, implicating that miR-218-5p promotes lipogenesis by targeting ELOVL5 in NAFLD. miR-218-5p could promote fatty acid synthesis by targeting Elovl5, thereby accelerating the development of NAFLD, which is one of the key pathogenic mechanisms of NAFLD and provides a new molecular target for the management of NAFLD.

A Metabolomics Study of Feces Revealed That a Disturbance of Selenium-Centered Metabolic Bioprocess Was Involved in Kashin-Beck Disease, an Osteoarthropathy Endemic to China

Background: Kashin-Beck disease (KBD) is a distinct osteoarthropathy in China with an unclear pathogenesis. This study aims to explore whether perturbations in the intestine metabolome could be linked to KBD individuals. Methods: An investigation was conducted in KBD endemic villages and fecal samples were collected. After applying inclusion and exclusion criteria, a total of 75 subjects were enrolled for this study, including 46 KBD (including 19 Grade I KBD and 27 Grade II KBD) and 29 controls. Untargeted metabolomics analysis was performed on the platform of UHPLC-MS. PLS-DA and OPLS-DA were conducted to compare the groups and identify the differential metabolites (DMs). Pathway analysis was conducted on MPaLA platform to explore the functional implication of the DMs. Results: Metabolomics analysis showed that compared with the control group, KBD individuals have a total of 584 differential metabolites with dysregulated levels such as adrenic acid (log2FC = -1.87, VIP = 4.84, p = 7.63 × 10-7), hydrogen phosphate (log2FC = -2.57, VIP = 1.27, p = 1.02 × 10-3), taurochenodeoxycholic acid (VIP = 1.16, log2FC = -3.24, p = 0.03), prostaglandin E3 (VIP = 1.17, log2FC = 2.67, p = 5.61 × 10-4), etc. Pathway analysis revealed several significantly perturbed pathways associated with KBD such as selenium micronutrient network (Q value = 3.11 × 10-3, Wikipathways), metabolism of lipids (Q value = 8.43 × 10-4, Reactome), free fatty acid receptors (Q value = 3.99 × 10-3, Reactome), and recycling of bile acids and salts (Q value = 2.98 × 10-3, Reactome). Subgroup comparisons found a total of 267 differential metabolites were shared by KBD vs. control, KBD II vs. control, and KBD I vs. control, while little difference was found between KBD II and KBD I (only one differential metabolite detected). Conclusions: KBD individuals showed distinct metabolic features characterized by perturbations in lipid metabolism and selenium-related bioprocesses. Our findings suggest that the loss of nutrients metabolism balance in intestine was involved in KBD pathogenesis. Linking the nutrients metabolism (especially selenium and lipid) to KBD cartilage damage should be a future direction of KBD study.

The effect of feeding fermented distillers' grains diet on the intestinal metabolic profile of Guanling crossbred cattle

Fermented distiller's grains (FDG)-based diets are nutritious and can improve the growth and intestinal immunity in livestock. However, there is limited research examining the effect of feeding FDG-based diets on changes in intestinal metabolites and related pathways in livestock. In this study, nine Guanling crossbred cattle (Guizhou Guanling Yellow cattle × Simmental cattle) were selected and randomly divided into a basal diet (BD) group and two experimental groups fed with FDG replacing 15% and 30% of the daily ration concentrates (FDG-Case A and FDG-Case B), respectively, with three cattle in each group. Fresh jejunum (J) and cecum (C) tissues were collected for metabolomic analysis. Differential metabolites and metabolic pathways were explored by means of univariate and multivariate statistical analysis. Compared with the J-BD group, 30 and 100 differential metabolites (VIP > 1, p < 0.05) were obtained in the J-FDG-Case A group and J-FDG-Case B group, respectively, and the J-FDG-Case B vs. J-FDG-Case A comparison revealed 63 significantly differential metabolites, which were mainly divided into superclasses including lipids and lipid-like molecules, organoheterocyclic compounds, and organic acids and derivatives. Compared with the C-BD, 3 and 26 differential metabolites (VIP > 1, p < 0.05) were found in the C-FDG-Case A group and C-FDG-Case B group, respectively, and the C-FDG-Case B vs. C-FDG-Case A comparison revealed 21 significantly different metabolites, which were also mainly divided into superclasses including lipids and lipid-like molecules, organoheterocyclic compounds, and organic acids and derivatives. A total of 40 metabolic pathways were identified, with a significance threshold set at p < 0.05. Among them, 2, 14, and 18 metabolic pathways were significantly enriched in the J-FDG-Case A vs. J-BD, J-FDG-Case B vs. J-BD, and J-FDG-Case B vs. J-FDG-Case A comparisons, respectively. Meanwhile, 1, 2, and 3 metabolic pathways were obtained in the C-FDG-Case A vs. C-BD, C-FDG-Case B vs. C-BD, and C-FDG-Case B vs. C-FDG-Case A comparisons, respectively. Furthermore, four significant metabolic pathways, namely insulin resistance, biosynthesis of unsaturated fatty acids, linoleic acid metabolism, and primary bile acid biosynthesis, were significantly enriched in Guanling crossbred cattle fed FDG diets. These results suggest that feeding FDG diets may promote the growth and intestinal immunity of Guanling crossbred cattle by regulating metabolic patterns of lipid compounds and related metabolic pathways. This study sheds light on the potential metabolic regulatory mechanisms of FDG diets and offers some references for their use in livestock feed.

Huangqin Decoction ameliorates ulcerative colitis by regulating fatty acid metabolism to mediate macrophage polarization via activating FFAR4-AMPK-PPARα pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Huangqin Decoction (HQD), a traditional Chinese medicine (TCM) formula chronicled in Shang Han Lun, is safe and effective for treatment of ulcerative colitis (UC).

AIM OF THE STUDY

To investigate the effect of HQD against dextran sulfate sodium (DSS)-induced UC mice by regulating gut microbiota and metabolites, and further explore the mechanism of fatty acid metabolism on macrophage polarization.

MATERIALS AND METHODS

Based on 3% dextran sulfate sodium (DSS)-induced UC mice model, clinical symptoms observation (body weight, DAI, and colon length) and histological inspection were used to evaluate the efficacy of HQD and fecal microbiota transplantation (FMT) from HQD-treated mice. The gut microbiota and metabolites were detected by 16S rRNA sequencing and metabolomics analysis. The parameters of fatty acid metabolism, macrophage polarization, and FFAR1/FFAR4-AMPK-PPARα pathway were analyzed by immunofluorescence analysis, western blotting, and real-time PCR. Then, the effects of FFAR1 and FFAR4 on macrophage polarization were examined by agonists based on LPS-induced RAW264.7 cell model.

RESULTS

The results showed that FMT, like HQD, ameliorated UC by improving weight loss, restoring colon length, and reducing DAI scores and histopathological scores. Besides, HQD and FMT both enhanced the richness of gut microbiota, and modulated intestinal bacteria and metabolites to achieve a new balance. Untargeted metabolomics analysis revealed that fatty acids, especially long-chain fatty acids (LCFAs), dominated in HQD against DSS-induced UC by regulating the gut microenvironment. Further, FMT and HQD recovered the expression of fatty acid metabolism-related enzymes, and simultaneously activated FFAR1/FFAR4-AMPK-PPARα pathway but suppressed NF-κB pathway. Combined with cell experiment, HQD and FMT promoted macrophage polarization from M1 toward M2, which were well associated with anti-inflammatory cytokines and combined with the activated FFAR4.

CONCLUSIONS

The mechanism of HQD against UC was related to regulating fatty acid metabolism to mediate M2 macrophage polarization by activating the FFAR4-AMPK-PPARα pathway.

TRPV1 regulates ApoE4-disrupted intracellular lipid homeostasis and decreases synaptic phagocytosis by microglia

Although the ε4 allele of the apolipoprotein E (ApoE4) gene has been established as a genetic risk factor for many neurodegenerative diseases, including Alzheimer's disease, the mechanism of action remains poorly understood. Transient receptor potential vanilloid 1 (TRPV1) was reported to regulate autophagy to protect against foam cell formation in atherosclerosis. Here, we show that ApoE4 leads to lipid metabolism dysregulation in microglia, resulting in enhanced MHC-II-dependent antigen presentation and T-cell activation. Lipid accumulation and inflammatory reactions were accelerated in microglia isolated from TRPV1^flox/flox; Cx3cr1^cre-ApoE4 mice. We showed that metabolic boosting by treatment with the TRPV1 agonist capsaicin rescued lipid metabolic impairments in ApoE4 neurons and defects in autophagy caused by disruption of the AKT-mTOR pathway. TRPV1 activation with capsaicin reversed ApoE4-induced microglial immune dysfunction and neuronal autophagy impairment. Capsaicin rescued memory impairment, tau pathology, and neuronal autophagy in ApoE4 mice. Activation of TRPV1 decreased microglial phagocytosis of synapses in ApoE4 mice. TRPV1 gene deficiency exacerbated recognition memory impairment and tau pathology in ApoE4 mice. Our study suggests that TRPV1 regulation of lipid metabolism could be a therapeutic approach to alleviate the consequences of the ApoE4 allele.

Identification of biomarkers associated with the feed efficiency by metabolomics profiling: results from the broiler lines divergent for high or low abdominal fat content

Background

Improving feed efficiency (FE) is one of the main objectives in broiler breeding. It is difficult to directly measure FE traits, and breeders hence have been trying to identify biomarkers for the indirect selection and improvement of FE traits. Metabolome is the "bridge" between genome and phenome. The metabolites may potentially account for more of the phenotypic variation and can suitably serve as biomarkers for selecting FE traits. This study aimed to identify plasma metabolite markers for selecting high-FE broilers. A total of 441 birds from Northeast Agricultural University broiler lines divergently selected for abdominal fat content were used to analyze plasma metabolome and estimate the genetic parameters of differentially expressed metabolites.

Results

The results identified 124 differentially expressed plasma metabolites (P < 0.05) between the lean line (high-FE birds) and the fat line (low-FE birds). Among these differentially expressed plasma metabolites, 44 were found to have higher positive or negative genetic correlations with FE traits (|r_g| ≥ 0.30). Of these 44 metabolites, 14 were found to display moderate to high heritability estimates (h² ≥ 0.20). However, among the 14 metabolites, 4 metabolites whose physiological functions have not been reported were excluded. Ultimately, 10 metabolites were suggested to serve as the potential biomarkers for breeding the high-FE broilers. Based on the physiological functions of these metabolites, reducing inflammatory and improving immunity were proposed to improve FE and increase production efficiency.

Conclusions

According to the pipeline for the selection of the metabolite markers established in this study, it was suggested that 10 metabolites including 7-ketocholesterol, dimethyl sulfone, epsilon-(gamma-glutamyl)-lysine, gamma-glutamyltyrosine, 2-oxoadipic acid, L-homoarginine, testosterone, adenosine 5'-monophosphate, adrenic acid, and calcitriol could be used as the potential biomarkers for breeding the "food-saving broilers".

Changes in plasma fatty acids profile in hyperketonemic ewes during early lactation: a preliminary study

The transition from late pregnancy to early lactation is characterized by marked changes in energy balance of dairy ruminants. The mobilization of adipose tissue led to an increase in plasma non-esterified fatty acids (NEFA) and β-hydroxybutyrate (BHB). The aim of this study was to analyze the total plasma fatty acids of healthy and hyperketonemic dairy ewes in early lactation through gas chromatography (GC) to evaluate metabolic alterations. An observational study was used with a cross-sectional experimental design. Forty-six Sarda dairy ewes were enrolled in the immediate post-partum (7 ± 3 days in milk) and divided into two groups according to serum BHB concentration: non-hyperketonemic group (n = 28; BHB < 0.86 mmol/L) and hyperketonemic group (n = 18; BHB ≥ 0.86 mmol/L). A two-way ANOVA included the effect of group and parity was used to evaluate differences in fatty acids (FA) concentrations. A total of 34 plasma FA was assessed using GC. 12 out of 34 FA showed a significant different between groups and 3 out of 34 were tended to significance. Only NEFA concentration and stearic acid were influenced by parity. The results may suggest possible links with lipid metabolism, inflammatory and immune responses in hyperketonemic group. In conclusion, GC represents a useful tool in the study of hyperketonemia and primiparous dairy ewes might show a greater risk to develop this condition.

Alteration of Bile Acids and Omega-6 PUFAs Are Correlated With the Progression and Prognosis of Drug-Induced Liver Injury

Background & Aims

Drug-induced liver injury (DILI) is one of the leading causes of liver failure with some of the patients progressed to chronic DILI. The mechanisms underlying the severity and chronicity of DILI are poorly elucidated and the biomarkers are limited. Metabolites and gut microbiota played a crucial role in the development of various liver diseases. Herein, a systematic analysis of serum metabolites and gut microbiota was performed in DILI patients, aiming to identify metabolites correlated with the progression and clinical prognosis of DILI.

Methods

Various serum metabolites were quantitated using a metabolite array technology in this prospective study. Gut microbiome compositions and the expression profiles of liver genes were determined in patients with DILI and healthy controls.

Results

Metabolomic analysis revealed that bile acids (BAs) and polyunsaturated fatty acids (PUFAs) were closely related to DILI severity and chronicity respectively. The ratios of serum primary/secondary BAs and omega-6/omega-3 PUFAs were elevated in DILI patients. A model established by adrenic acid (AdA) and aspartic acid (Asp) exerts good performance for predicting the chronicity of DLIL. Hepatic transcriptome revealed enhanced expression of PUFA peroxidation and supressed expression of BA synthesis related genes in DILI patients. In addition, Lactic acid bacteria and BA converting bacteria were increased in gut of DILI patients. Besides, elevated serum malondialdehyde (MDA) and fibroblast growth factor 19 (FGF19) was observed in DILI patients.

Conclusion

BAs and PUFAs could be potent markers for the severity and chronicity of DILI respectively. The panel of AdA and Asp could be ideal predictive model for the risk of chronicity at the acute stage of DILI. Gut microbiota might act as a negative feedback mechanism to maintain the homeostasis of BAs and PUFAs via FGF19 signalling and PUFA saturation, respectively. Our study revealed novel biomarkers for severe and chronic DILI and provided new therapeutic targets for DILI.

Differences of the Plasma Total Lipid Fraction from Pre-Foaling to Post-Foaling Period in Donkeys

Simple Summary

An association between increased metabolic demands and reduced dry matter intake is observed from late gestation to early lactation in donkeys. Furthermore, little is known about the nutritional and energy requirements of this period in animals. Changes in energy metabolism make donkeys more susceptible to metabolic diseases such as hyperlipemia, which is characterized by the mobilization of fatty acids from adipose tissue. A better knowledge of this period could improve animal husbandry, well-being, and health. The aim of this study was to analyze the plasma total lipid fraction, to highlight metabolic changes from the pre-foaling to post-foaling periods, using the gas chromatography technique. Our findings reveal a greater risk of metabolic disease in late gestation to early lactation in donkeys.

Abstract

The period from late gestation to early lactation is characterized by changes in energy metabolism. The aim of the current study was to analyze the plasma total lipid fraction using gas chromatography (GC) analysis, in order to highlight metabolic changes from the pre-foaling to post-foaling periods. Eleven pluriparous dairy jennies (mean age of 11.88 ± 3.79 years) belonging to the Amiata donkey breed were enrolled. Blood sampling was performed at 15 days before foaling (T0), and 15 (T1), 30 (T2), 60 (T3), and 90 (T4) days after foaling, for biochemical and GC analysis. A total of 37 fatty acids were identified in plasma samples: 4 medium chain (MCFA), 24 long chain (LCFA), and 9 very-long chain (VLCFA) fatty acids. Among them, 20 fatty acids changed significantly, and two fatty acid showed a trend toward significance. Furthermore, the LCFA, saturated, unsaturated, monounsaturated, and polyunsaturated ω-3 fatty acids changed significantly during the study period. The main alterations were between T0 and the other time points and appeared to be related to lipid metabolism, cellular structure and function, and inflammatory and immune responses. Our findings reveal greater energy requirements at the end of gestation compared to early lactation in donkeys.

The Gut Barrier, Intestinal Microbiota, and Liver Disease: Molecular Mechanisms and Strategies to Manage

Liver disease encompasses pathologies as non-alcoholic fatty liver disease, non-alcoholic steatohepatitis, alcohol liver disease, hepatocellular carcinoma, viral hepatitis, and autoimmune hepatitis. Nowadays, underlying mechanisms associating gut permeability and liver disease development are not well understood, although evidence points to the involvement of intestinal microbiota and their metabolites. Animal studies have shown alterations in Toll-like receptor signaling related to the leaky gut syndrome by the action of bacterial lipopolysaccharide. In humans, modifications of the intestinal microbiota in intestinal permeability have also been related to liver disease. Some of these changes were observed in bacterial species belonging Roseburia, Streptococcus, and Rothia. Currently, numerous strategies to treat liver disease are being assessed. This review summarizes and discusses studies addressed to determine mechanisms associated with the microbiota able to alter the intestinal barrier complementing the progress and advancement of liver disease, as well as the main strategies under development to manage these pathologies. We highlight those approaches that have shown improvement in intestinal microbiota and barrier function, namely lifestyle changes (diet and physical activity) and probiotics intervention. Nevertheless, knowledge about how such modifications are beneficial is still limited and specific mechanisms involved are not clear. Thus, further in-vitro, animal, and human studies are needed.