Decaisnea insignis Seed Oil Inhibits Trimethylamine-N-oxide Formation and Remodels Intestinal Microbiota to Alleviate Liver Dysfunction in l-Carnitine Feeding Mice

Mechanism of Metabolic Response to Hepatectomy by Integrated Analysis of Gut Microbiota, Metabolomics, and Proteomics

Hepatectomy is a common clinical procedure for the treatment of many liver diseases, and the successful recovery of a patient's liver metabolism and function after surgery is crucial for a good prognosis. The objective of this study was to elucidate the metabolic response to hepatectomy using high-throughput sequencing analysis of 16S rRNA gene, metabolomics, and proteomics data. Fecal and serum samples from beagle dogs were collected on day 0 (LH0), day 7 (LH7), and day 28 (LH28) after laparoscopic partial hepatectomy. Liver tissue samples were taken on LH0 and LH7. Dysbiosis in the fecal microbiota was explored, and host-microbiome interactions based on global metabolic and protein profiles and inflammatory processes were determined. Results showed that the relative abundance of Allobaculum and Turicibacter was decreased and that of Escherichia-Shigella was increased after hepatectomy (P < 0.05); the phenylalanine, tyrosine, and tryptophan biosynthetic pathway, along with the phenylalanine and aminoacyl-tRNA biosynthetic pathway, was significantly associated with liver injury. The serum metabolites l-phenylalanine and l-arginine were useful as biomarkers, and the fecal metabolite l-threonine was a signature target monitor for liver recovery. The proteomics profile revealed 412 significantly different proteins and further highlighted two key signaling pathways (mitogen-activated protein kinase [MAPK] and peroxisome proliferator-activated receptor [PPAR]) involved in the response to liver injury. We systematically explored the metabolic mechanism of liver injury and recovery, providing new insights into effective ways to promote recovery after hepatectomy and improve liver function and long-term survival. These fundamental studies on hepatectomy will provide the basis for future advances in treatment and recovery from common liver diseases. IMPORTANCE As the largest parenchymal organ, the liver is a target for bacterial and viral infections, nonalcoholic fatty liver disease (NAFLD), cirrhosis, cancer, and many other diseases, constituting a serious worldwide problem. The treatment for many of these diseases involves hepatectomy. Here, we show that aberrant inflammatory processes after hepatectomy of the liver as reflected in the association between liver metabolism and gut microbiota create a grave risk. This study investigated the mechanisms of gut microbiota and host metabolism involved in liver injury and recovery after hepatectomy, using proteomics to reveal the mechanisms of postoperative liver injury and a comprehensive multi-omics approach to identify changes in metabolism after hepatectomy.

A high-fat diet disrupts the hepatic and adipose circadian rhythms and modulates the diurnal rhythm of gut microbiota-derived short-chain fatty acids in gestational mice

The prevalence of gestational obesity has reached epidemic proportions. Evidence supported that the interactions between the gut microbiota and circadian clocks far reached, affecting host metabolism. Our study aimed to investigate the effect of a high-fat diet (HF) on the hepatic and adipose circadian rhythms in gestational mice and to explore the role of gut microbiota-derived short-chain fatty acids (SCFAs) in mediating the effects. C57BL/6 female mice were randomly fed a standard chow diet (Ctr) or HF prior to and during pregnancy. Samples were collected every 4 h over 24 h (six time points), and 16S rRNA and metabonomics were carried out. Rhythmic patterns were identified and compared using CircaCompare. The results showed that the HF before and during pregnancy significantly induced obesity and worsen glucose tolerance, insulin sensitivity, and lipid metabolism in the gestational mice. Furthermore, the HF significantly disrupted the rhythmic pattern of hepatic and adipose circadian clock genes and downstream metabolic genes. Importantly, our results revealed that the HF altered the diurnal rhythm of the gut microbiota in a diverse manner, which was assessed across three categories: phase shift, loss rhythmicity, and gained rhythmicity. We report here, for the first time, a parallel alteration of the rhythmic phase of butyric acid and butyrate-producing Clostridiaceae_1, which was confirmed by a positive correlation between them. Overall, our research emphasized the importance of the rhythmicity of gut microbiota-derived SCFAs in mediating circadian disruption in response to the HF in gestational mice, which may provide novel insights into the prevention and treatment of gestational obesity.

SiNiSan alleviates liver injury by promoting hepatic stem cell differentiation via Wnt/β-catenin signaling pathway

BACKGROUND

SiNiSan, a Traditional Chinese Medicine containing Radix Bupleuri, Radix Paeoniae Alba, Fructus Aurantii Immaturus, and Radix Glycyrrhizae, has been shown to be clinically effective in treating liver damage, its underlying molecular mechanisms however remains unclear.

PURPOSE

The aim of the current study was to understand the molecular mechanisms of SiNiSan in the treatment of liver damage utilizing mice and cell culture models.

METHODS

Here, mice were gavaged with 0.2% CCl4 to obtain acute liver injury model and with alcohol to obtain chronic liver injury model. H&E staining was performed to detect liver histomorphology. HPLC-MS was performed to analyze the composition of SiNiSan decoction and SiNiSan-medicated serum (SMS). In addition, western blots were done to analyze the representative protein expression in Wnt/β-catenin signaling. Immunofluorescence staining was done to analyze the protein levels in WB-F344 cells. Finally, in an attempt to measure the influence of SiNiSan on liver regeneration in rats, we constructed a rats partial hepatectomy models.

RESULTS

We demonstrated that SiNiSan treatment mitigated liver damage in mice, as evidenced by the decrease in serum AST and ALT levels, as well as improved liver tissue morphology. HPLC-MS results showed that SMS contained a variety of components from the SiNiSan decoction. Next, our results showed that SMS reduced the expression of α-fetoprotein (AFP) and enhanced the expression of albumin (ALB) and cytokeratin 19 (CK19) in WB-F344 cells. Further, SMS treatment induced the accumulation of β-catenin. After 14 days of SMS treatment, β-catenin protein underwent nuclear translocation and bound to the LEF1 receptor in the nucleus, which regulated c-Myc and Cyclin D1 factors to activate Wnt/β-catenin signaling and promoted differentiation of WB-F344 cells. In addition, we demonstrated that SiNiSan increased liver regeneration in rat hepatectomy.

CONCLUSION

Collectively, the current study revealed that SiNiSan alleviated the acute liver injury induced by CCl4 as well as the chronic liver damage triggered by alcohol and sucrose in vitro. Concurrently, SMS treatment induced hepatic stem cell differentiation by activating Wnt/β-catenin signaling in vivo. Further study showed that SiNiSan promoted the regeneration of rats liver. The current study provides a theoretical basis for the clinical treatment of liver-related diseases with SiNiSan.

Chlorogenic acid inhibits trimethylamine-N-oxide formation and remodels intestinal microbiota to alleviate liver dysfunction in high L-carnitine feeding mice

High L-carnitine ingestion has been shown to cause liver injury, mechanically due to an elevated circulating level of trimethylamine-N-oxide (TMAO), a gut microbiota-derived metabolite from L-carnitine. This study aimed to investigate whether chlorogenic acid (CGA), a health-promoting polyphenol, could inhibit TMAO formation and thereafter might prevent L-carnitine-induced liver injury in mice. Feeding of mice with 3% L-carnitine in drinking water increased the serum and urinary levels of TMAO (p < 0.01 vs. Normal), whereas the serum and urinary TMAO formation was sharply reduced by CGA administration (p < 0.01). At the phylum level, CGA inhibited the L-carnitine-induced increase in the abundance of Firmicutes and Proteobacteria, while it promoted Bacteroidetes. At the genus level, CGA notably increased the abundance of Akkermansia and Bacteroides, but reduced the population of Erysipelatoclostridium, Faecalibaculum and Erysipelotrichaceae in high L-carnitine feeding mice. Meanwhile, CGA caused strong inhibition against the increase of liver injury markers (i.e. AST, ALT and ALP), hepatic inflammatory cytokines (i.e. IL-1, IL-6, TNF-α and TNF-β) and dyslipidemia (i.e. TC, TG, LDL-C and HDL-C) in L-carnitine-fed mice (p < 0.05). These findings suggest that CGA holds great potential to alleviate liver dysfunction induced by high L-carnitine ingestion. The beneficial effect might be attributed to the protection against TMAO formation and the improvement of the health-promoting gut microbiota, as well as the antioxidant and anti-inflammatory properties of CGA.

Dingxin Recipe IV attenuates atherosclerosis by regulating lipid metabolism through LXR-α/SREBP1 pathway and modulating the gut microbiota in ApoE-/- mice fed with HFD

ETHNOPHARMACOLOGICAL RELEVANCE

Dingxin Recipe (DXR) is a traditional Chinese medicine formula that has been reported to be effective and safe treatment for cardiovascular diseases, such as arrhythmias, coronary heart disease. Dingxin Recipe IV (DXR IV) was further improved from the DXR according to the traditional use. However, the mechanism of DXR IV in atherosclerosis is unclear.

AIM OF THE STUDY

This study aimed to illustrate whether DXR IV improve atherosclerosis through modulating the lipid metabolism and gut microbiota in atherosclerosis mice.

MATERIALS AND METHODS

40 male ApoE^-/- mice were fed on HFD for 12 weeks and were then treated with DXR IV (1.8, 0.9, or 0.45 g/kg/d) for another 12 weeks. The decroation of DXR IV contains four traditional Chinese medicines: the dried rhizome of Coptis chinensis Franch. (15.09%), the root of Salvia miltiorrhiza Bunge (28.30%), the seed of Ziziphus jujuba Mill. (37.74%) and the fruiting body of Ganoderma lucidum (Leyss.ex Fr.) Karst. (18.87%). 8 male c57BL/6 mice fed a normal diet served as control group. The atherosclerotic plaque was quantified by oil-red O staining and masson trichrome staining. Mice feces were collected. The gut micobiota were detected by 16S rRNA gene sequencing and fecal metabolites were analyzed by ¹H NMR spectroscopy. The effect of DXR IV on blood lipids (TG, TC, LDL-C, HDL-C) was investigated. The lipid metabolism related genes were determined by RT-qPCR and western blotting respectively.

RESULTS

DXR IV exerted the anti-atherosclerosis effect by inhibiting the excessive cholesterol deposition in aorta and regulating the level of TG, TC, LDL-C and HDL-C. The composition of gut microbiota was changed. Interestingly, the relative abundance of Muribaculaceae and Ruminococcaceae increased after DXR IV administration, whereas the abundance of Erysipelotrichaceae decreased, which have been beneficial to lipid metabolism. Nine potential metabolic biomarkers, including acetate, butyrate, propionate, alanine, succinate, valerate, xylose, choline, glutamate, were identified, which were related to fatty acid metabolism. Further, the pathway of fatty acid was detected by the RT-qPCR and western blotting. Compared with model group, the level of LXR-α and SREBP1 decreased significantly in DXR IV group while LXR-β, SREBP2 showed no statistical significance. It indicated that DXR IV modulated lipid metabolism by LXR-α/SREBP1 but not LXRβ and SREBP2.

CONCLUSIONS

DXR IV exhibits potential anti-atherosclerosis effect, which is closely related to lipid metabolism and the gut microbiota. This study may provide novel insights into the mechanism of DXR IV on atherosclerosis and a basis for promising clinical usage.

Dietary bioactive ingredients to modulate the gut microbiota-derived metabolite TMAO. New opportunities for functional food development

There is a growing body of clinical evidence that supports a strong association between elevated circulating trimethylamine N-oxide (TMAO) levels with increased risk of developing adverse cardiovascular outcomes such as atherosclerosis and thrombosis. TMAO is synthesized through a meta-organismal stepwise process that involves (i) the microbial production of TMA in the gut from dietary precursors and (ii) its subsequent oxidation to TMAO by flavin-containing monooxygenases in the liver. Choline, l-carnitine, betaine, and other TMA-containing compounds are the major dietary precursors of TMA. TMAO can also be absorbed directly from the gastrointestinal tract after the intake of TMAO-rich foods such as fish and shellfish. Thus, diet is an important factor as it provides the nutritional precursors to eventually produce TMAO. A number of studies have attempted to associate circulating TMAO levels with the consumption of diets rich in these foods. On the other hand, there is growing interest for the development of novel food ingredients that reduce either the TMAO-induced damage or the endogenous TMAO levels through the interference with microbiota and host metabolic processes involved in TMAO pathway. Such novel functional food ingredients would offer great opportunities to control circulating TMAO levels or its effects, and potentially contribute to decrease cardiovascular risk. In this review we summarize and discuss current data regarding the effects of TMA precursors-enriched foods or diets on circulating TMAO levels, and recent findings regarding the circulating TMAO-lowering effects of specific foods, food constituents and phytochemicals found in herbs, individually or in extracts, and their potential beneficial effect for cardiovascular health.

Leuconostoc pseudomesenteroides improves microbiota dysbiosis and liver metabolism imbalance and ameliorates the correlation between dihydroceramide and strains of Firmicutes and Proteobacteria in high fat diet obese mice

Leuconostoc pseudomesenteroides is widely isolated from fermented foods; however, the underlying molecular mechanism behind its anti-obesity function has rarely been studied. This study aims to explore the role of alterations in gut microbes and liver metabolites mediated by Leuconostoc pseudomesenteroides (Tu) in obese mice for a period of 8 weeks through UPLC/Q-TOF-MS and 16S rRNA sequencing. Our results showed that Tu administration at a dosage of 1 × 10⁹ CFU per day per mouse effectively attenuated the weight of mice, significantly reduced serum lipids, and markedly improved fecal lipid output. Tu also ameliorated the lipid profiles in the liver and epididymal fat tissues, and restored intestinal disorder caused by a high-fat diet. Moreover, glycerophospholipid metabolism in the liver was altered by increased dihydroceramide levels. Surprisingly, the correlation between dihydroceramide and strains of Firmicutes and Proteobacteria was found for the first time. Collectively, these findings highlight that Tu could be a potential dietary supplement for weight control.

Bifidobacterium longum subsp. longum Remodeled Roseburia and Phosphatidylserine Levels and Ameliorated Intestinal Disorders and liver Metabolic Abnormalities Induced by High-Fat Diet

Bifidobacterium longum is considered as a potential supplement in antiobesity treatment; however, the underlying molecular mechanism has rarely been studied. To understand the contributions of B. longum subsp. longum (BL21) in the prevention of obesity, we investigated alterations in the liver metabonomic phenotype and gut microbiota by ultraperformance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry and 16S ribosomal RNA gene sequencing in C57BL/6J male mice orally administered with BL21 for 8 weeks [high-fat diet (HFD)]. BL21 at 1 × 109 CFU·day-1 per mouse reduced the weight of mice by 16.9% relative to that of the mice fed with HFD and significantly lowered the serum levels of total cholesterol, triglycerides, and low-density lipoprotein cholesterol. BL21 also ameliorated fat vacuolization in liver cells and epididymal fat accumulation. BL21 also lowered the Firmicutes/Bacteroidetes ratio, regulated liver remodeling in glycerophospholipids, and alleviated the levels of d-tryptophan. A positive correlation between the butyrate-producing strain Roseburia and the cell membrane component phosphatidylserine was found for the first time. Thus, BL21 can potentially prevent mice from being obese by rebalancing the gut microbiota and glycerophospholipid metabolism. BL21 can be a promising dietary supplement for weight control.