Prolyl Endopeptidase Gene Disruption Improves Gut Dysbiosis and Non-alcoholic Fatty Liver Disease in Mice Induced by a High-Fat Diet

Activation of prep expression by Tet2 promotes the proliferation of bipotential progenitor cells during liver regeneration

Biliary epithelial cell (BEC)-derived liver regeneration in zebrafish exhibits similarities to liver regeneration in chronic liver injury. However, the underlying mechanisms remain poorly understood. Here, we identified a serine peptidase called prolyl endopeptidase (Prep) as an indispensable factor during the BEC-derived liver regeneration process. prep was significantly upregulated and enriched in bipotential progenitor cells (BP-PCs). Through gain- and loss-of-function assays, prep was found to potently accelerate liver regeneration and drastically increase the proliferation of BP-PCs. Mechanistically, prep expression was directly regulated by ten-eleven translocation 2 (Tet2)-mediated DNA demethylation. More strikingly, Tet2 regulated prep expression by directly interacting and reducing the methylation of CpG sites in the prep promoter. Subsequently, Prep activated the PI3K-AKT-mTOR signaling pathway to regulate liver regeneration. Therefore, our study revealed the role and mechanism of Tet2-mediated DNA demethylation-associated upregulation of prep in the proliferation of BP-PCs during liver regeneration. These results identify promising targets for stimulating regeneration following chronic liver injury.

Neuregulin1 ameliorates metabolic dysfunction-associated fatty liver disease via the ERK/SIRT1 signaling pathways

BACKGROUND

Neuregulin (NRG) family is involved in energy metabolism, among which NRG1 is a neuregulin proved to play a protective role in MAFLD cells. But the presice echanism has not been fully illustrated. This study aimed to investigate the role of NRG1 via the ERK/SIRT1 signaling in the pathogenesis of MAFLD.

METHODS

C57BL/6 mice were fed with high-fat diet for 8 weeks, and then injected with NRG1 (0.3 mg/kg/d) and PD98059 (0.3 mg/kg/d) via tail vein for 5 weeks. HepG2 cells induced by oleic acid and palmitic acid were treated with 20ng/mL NRG1 and 10µmol/L PD98059. The changes of histopathological, biochemical indexes, inflammatory factors, lipid metabolism, apoptosis and autophagy parameters were measured.

RESULTS

The expressions of NRG1 in MAFLD cell and animal models were significantly lower than that in the control group. After the intervention of ERK inhibitor PD98059, the expression of NRG1 decreased significantly in vivo, but no significant change was observed in vitro. Moreover, NRG1 ameliorated hepatic steatosis, enhanced cell viability, reduced cell apoptosis, and attenuated liver injury both in vitro and in vivo. After NRG1 intervention, the expressions of ERBB2, ERBB3, p-ERK1/2, SIRT1 and p-FOXO1 as well as the LC3II/I ratio in MAFLD cells and liver tissues of MAFLD mice were significantly increased, while the expression of SREBP1c was decreased. The aforementioned therapeutic effect of NRG1 was lost after the intervention of PD98059.

CONCLUSION

NRG1 might play a protective role in the pathogenesis of MAFLD by activating the downstream ERK1/2 through ErbB2-ErbB3, which promotes the expression of SIRT1 and autophagy markers. This study might indicate a new therapeutic strategy for MAFLD.

Berberine Protects against High-Energy and Low-Protein Diet-Induced Hepatic Steatosis: Modulation of Gut Microbiota and Bile Acid Metabolism in Laying Hens

Berberine (BBR) is a natural alkaloid with multiple biotical effects that has potential as a treatment for fatty liver hemorrhagic syndrome (FLHS). However, the mechanism underlying the protective effect of BBR against FLHS remains unclear. The present study aimed to investigate the effect of BBR on FLHS induced by a high-energy, low-protein (HELP) diet and explore the involvement of the gut microbiota and bile acid metabolism in the protective effects. A total of 90 healthy 140-day-old Hy-line laying hens were randomly divided into three groups, including a control group (fed a basic diet), a HELP group (fed a HELP diet), and a HELP+BBR group (high-energy, high-protein diet supplemented with BBR instead of maize). Our results show that BBR supplementation alleviated liver injury and hepatic steatosis in laying hens. Moreover, BBR supplementation could significantly regulate the gut's microbial composition, increasing the abundance of Actinobacteria and Romboutsia. In addition, the BBR supplement altered the profile of bile acid. Furthermore, the gut microbiota participates in bile acid metabolism, especially taurochenodeoxycholic acid and α-muricholic acid. BBR supplementation could regulate the expression of genes and proteins related to glucose metabolism, lipid synthesis (FAS, SREBP-1c), and bile acid synthesis (FXR, CYP27a1). Collectively, our findings demonstrate that BBR might be a potential feed additive for preventing FLHS by regulating the gut microbiota and bile acid metabolism.

Constipation is associated with depression of any severity, but not with suicidal ideation: insights from a large cross-sectional study

OBJECTIVE

The association between constipation and depression or suicidal ideation (SI) has not been adequately studied. This study aims to examine whether constipation is associated with depression or SI in US adults.

METHOD

4,562 adults aged 20 and older were selected from the National Health and Nutrition Examination Survey 2009-2010 for the sample. The Bowel Health Questionnaire provided constipation information. Clinical depression and depression severity were assessed by the validated Patient Health Questionnaide-9 (PHQ-9), and item 9 of the PHQ-9 assessed SI. Adjusted odds ratios (ORs) were calculated using multivariate logistic regression models. Stability of the results was ensured by a subgroup analysis.

RESULT

After adjusting for covariates such as demographics, risk behaviors, associated comorbidities, dietary intake, and related medications, the PHQ-9 score and clinical depression were both significantly associated with constipation, with ORs and 95%CIs of 1.13 (1.10-1.16) and 3.76 (2.65-5.34). Depression of all severities was also significantly associated with constipation. The ORs and 95%CIs of constipation with mild depression, moderate depression, and moderately severe to severe depression were 2.21 (1.54-3.16), 3.69 (2.34-5.81) and 6.84 (4.19-11.15), respectively. Subgroup analyses showed no statistically significant interactions (P > 0.05), and the association was stronger in men than in women (OR: 7.81, 95%CI: 3.67-16.61 vs OR: 3.46, 95%CI: 2.31-5.19). The association between constipation and SI was not significant (OR: 1.36, 95%CI: 0.78-2.37).

CONCLUSION

In conclusion, constipation was significantly associated with depression of any severity, but not with SI, suggesting that enough attention should be paid to the emotional and psychological status of patients with constipation, especially male patients.