Tetrahydrocurcumin ameliorates hepatic steatosis by restoring hepatocytes lipophagy through mTORC1-TFEB pathway in nonalcoholic steatohepatitis.

PURPOSE: To investigate the therapeutic effect and underlying mechanism of tetrahydrocurcumin (THC) on nonalcoholic steatohepatitis (NASH) induced by high-fat diet (HFD). METHODS: NASH rat model was established through long-term feeding HFD, and the steatosis cell model was stimulated via palmitate acid (PA). The therapeutic effect of THC was evaluated in terms of liver function, lipid metabolism, liver pathophysiology, inflammation and oxidative stress in vivo, and lipid accumulation in vitro. The alteration in lipophagy was identified by using western blot and immunofluorescence. mTORC1-TFEB signaling pathway was measured by qRT-PCR, western blot and protein-ligand docking. In addition, chloroquine and MHY1485 were further introduced to validate the effect of THC on lipophagy and mTORC1-TFEB signaling pathway, respectively. RESULTS: THC effectively improved hepatic steatosis, inflammation and oxidative stress in NASH rats, and reduced lipid accumulation in steatosis L02 cells and Hep G2 cells. THC promoted lipophagy with increasing LC3B-II as well as decreasing P62 expression via lysosomal biogenesis upregulation, which was greatly weakened after chloroquine intervention. mTORC1-TFEB is a critical pathway for regulating lysosome in autophagy, THC treatment induced TFEB nucleus translocation via inhibiting mTORC1 to upregulate lysosomal biogenesis. However, these effects were partly eliminated by mTORC1 activator MHY1485. CONCLUSION: THC restored lipophagy to reduce lipid accumulation by regulating mTORC1-TFEB pathway in NASH rats and steatosis hepatocytes. These findings suggested that THC represents a therapeutic candidate for NASH treatment.

Tetrahydroberberine alleviates high-fat diet-induced hyperlipidemia in mice via augmenting lipoprotein assembly-induced clearance of low-density lipoprotein and intermediate-density lipoprotein.

The promotion of excess low-density lipoprotein (LDL) clearance stands as an effective clinical approach for treating hyperlipidemia. Tetrahydroberberine, a metabolite of berberine, exhibits superior bioavailability compared to berberine and demonstrates a pronounced hypolipidemic effect. Despite these characteristics, the impact of tetrahydroberberine on improving excessive LDL clearance in hyperlipidemia has remained unexplored. Thus, this study investigates the potential effects of tetrahydroberberine on high-fat diet-induced hyperlipidemia in mice. The findings reveal that tetrahydroberberine exerts a more potent lipid-lowering effect than berberine, particularly concerning LDL-cholesterol in hyperlipidemic mice. Notably, tetrahydroberberine significantly reduces serum levels of upstream lipoproteins, including intermediate-density lipoprotein (IDL) and very low-density lipoprotein, by promoting their conversion to LDL. This reduction is further facilitated by the upregulation of hepatic LDL receptor expression induced by tetrahydroberberine. Intriguingly, tetrahydroberberine enhances the apolipoprotein E (ApoE)/apolipoprotein B100 (ApoB100) ratio, influencing lipoprotein assembly in the serum. This effect is achieved through the activation of the efflux of ApoE-containing cholesterol in the liver. The ApoE/ApoB100 ratio exhibits a robust negative correlation with serum levels of LDL and IDL, indicating its potential as a diagnostic indicator for hyperlipidemia. Moreover, tetrahydroberberine enhances hepatic lipid clearance without inducing lipid accumulation in the liver and alleviates existing liver lipid content. Importantly, no apparent hepatorenal toxicity is observed following tetrahydroberberine treatment for hyperlipidemia. In summary, tetrahydroberberine demonstrates a positive impact against hyperlipidemia by modulating lipoprotein assembly-induced clearance of LDL and IDL. The ApoE/ApoB100 ratio emerges as a promising diagnostic indicator for hyperlipidemia, showcasing the potential clinical significance of tetrahydroberberine in lipid management.

Curcumin Alleviates High-fat Diet-induced Nonalcoholic Steatohepatitis via Improving Hepatic Endothelial Function with Microbial Biotransformation in Rats.

Hepatic endothelial function is central to the development of nonalcoholic steatohepatitis (NASH). Curcumin (Cur) is reportedly hepatoprotective, however, it remains unknown whether Cur improves hepatic endothelial function in NASH. Additionally, the poor bioavailability of Cur renders it difficult to elucidate its hepatoprotective effect, hence, its biotransformation should be considered. Herein, we investigated the effects and mechanisms of Cur and its bioconversion on hepatic endothelial function against high-fat diet-induced NASH in rats. The results revealed that Cur improved hepatic lipid accumulation, inflammation, and endothelial dysfunction by inhibiting NF-κB and PI3K/Akt/HIF-1α pathways, however, these effects were weakened via antibiotic addition, which was closely related to reduced tetrahydrocurcumin (THC) produce in the liver and intestinal content. Moreover, THC exerted a better effect than Cur on restoring liver sinusoidal endothelial cells function to attenuate steatosis and injury in L02 cells. Thus, these findings indicate that the effect of Cur on NASH is closely related to hepatic endothelial function improvement with intestinal microbial biotransformation.

High fructose-induced skeletal muscle insulin resistance could be alleviated by berberine via AMPD1 and ADSL.

AMP-activated protein kinase (AMPK) is a master regulator of energy homeostasis that is activated in response to an elevated intracellular AMP/ATP ratio. Although many studies have shown berberine is an AMPK activator widely used in metabolic syndrome, how to properly control AMPK activity remains obscure. Our present study aimed to examine the protective effect of berberine against fructose-induced insulin resistance in rats and L6 cells, as well as its potential activation mechanism on AMPK. The results showed that berberine effectively reversed body weight gain, Lee's index, dyslipidemia and insulin intolerance. Moreover, berberine alleviated inflammatory response, antioxidant capacity and promoted glucose uptake in vivo and in vitro. The beneficial effect was associated with upregulation of both Nrf2 and AKT/GLUT4 pathways, which were regulated by AMPK. Notably, berberine could increase the level of AMP and the ratio of AMP/ATP, then further activate AMPK. Mechanistic experiments revealed that berberine suppressed the expression of adenosine monophosphate deaminase 1 (AMPD1) and promoted the expression of adenylosuccinate synthetase (ADSL). Taken together, berberine exerted excellent therapeutic effect on insulin resistance. And its mode of action may be related to the AMP-AMPK pathway by regulating AMPD1 and ADSL.

Metformin alleviates long-term high-fructose diet-induced skeletal muscle insulin resistance in rats by regulating purine nucleotide cycle.

Nutrient excess caused by excessive fructose intake can lead to insulin resistance and dyslipidemia, which further causes the development of metabolic syndrome. Metformin is a well-known AMPK activator widely used for the treatment of metabolic syndrome, while the mechanism of AMPK activation remains unclear. The present study aimed to investigate the pharmacological effects of metformin on fructose-induced insulin resistance rat, and the potential mechanism underlying AMPK activation in skeletal muscle tissue. Results indicated that metformin significantly ameliorated features of insulin resistance, including body weight, Lee's index, hyperinsulinemia, dyslipidemia, insulin intolerance and pancreatic damage. Moreover, treatment with metformin attenuated the inflammatory response in serum and enhanced the antioxidant capacity in skeletal muscle tissue. The therapeutic effects of metformin on fructose-induced insulin resistance may be related to the activation of AMPK to regulate Nrf2 pathway and mitochondrial abnormality. Additionally, metformin suppressed the expression of adenosine monophosphate deaminase 1 (AMPD1) and up-regulated the expression of adenylosuccinate synthetase (ADSS) in the purine nucleotide cycle (PNC), which facilitated the increase of AMP level and the ratio of AMP/ATP. Therefore, we proposed a novel mechanism that metformin activated AMPK via increasing AMP by regulating the expression of AMPD1 and ADSS in PNC pathway.

Andrographolide sodium bisulfite ameliorates dextran sulfate sodium-induced colitis and liver injury in mice via inhibiting macrophage proinflammatory polarization from the gut-liver axis.

Ulcerative colitis (UC), an inflammatory disease, is widely thought to be associated with colonic barrier damage and inflammatory response. With the destruction of the colonic barrier, lipopolysaccharide (LPS) enters the liver through the portal vein and causes liver injury. Liver injury in turn exacerbates UC to form a vicious cycle, so the treatment of liver injury cannot be ignored. Andrographolide (Andro) has a protective effect against colitis and liver injury, but with low bioavailability. Andrographolide sodium bisulfite (ASB), a water-soluble sulfonate of Andro, has better bioavailability, whether it has a better curative effect against UC and liver injury is rarely reported. Hence, we investigated the protective effect and potential mechanism of ASB against dextran sulfate sodium (DSS)-induced UC and liver injury in mice. The results showed that treatment with ASB significantly relieved the clinical symptoms of UC and liver injury by reducing disease activity index, inhibiting gut-derived LPS leakage, and improving colonic and hepatic injury, and its curative effect was better than Andro. Moreover, ASB effectively decreased the YAP-mediated colonic inflammation and TLR4/MyD88/NF-κB-mediated pro-inflammatory factor release in the liver. Both colonic and hepatic inflammation were associated with macrophage proinflammatory polarization, but they were significantly inhibited by ASB. ASB showed good safety in the treatment of UC and liver injury and has no nephrotoxicity as previously described. In conclusion, ASB has an effective protective effect on DSS-induced UC and liver injury, mainly by suppressing macrophage proinflammatory polarization from the gut-liver axis.

ß-patchoulene protects against non-alcoholic steatohepatitis via interrupting the vicious circle among oxidative stress, histanoxia and lipid accumulation in rats.

Non-alcoholic steatohepatitis (NASH), an extreme progressive subtype of metabolic associated fatty liver disease, is well characterized by hepatic steatosis, injury and inflammation. It causes irreversible hepatic damage and there are no approved interventions for it. ß-PAE, a representatively pharmacological active substance isolated from Pogostemon cablin, has been indicated to alleviate hepatic steatosis and injury through modulating lipid metabolism in rats with simple steatosis. However, its protection against NASH remains unclear. Here, this study explored the potential effect of ß-PAE against high-fat diet-induced NASH in rats. The results displayed that ß-PAE significantly reduced the gains of body weight and epididymal adipose tissue, liver index and attenuated liver histological damages in NASH rats. It also markedly alleviated hepatic inflammation by inhibiting NLRP3 inflammasome activation. In NASH, the active NLRP3 inflammasome is caused by hepatic lipid abnormal accumulation-induced oxidative stress. Excessive oxidative stress results in hepatic histanoxia, which exacerbates lipid metabolism disorders by elevating CD36 to suppress AMPK signalling pathways. Moreover, the lipid accumulation led by lipid metabolism dysfunction intensifies oxidative stress. A vicious circle is formed among oxidative stress, histanoxia and lipid accumulation, eventually, but ß-PAE effectively interrupted it. Interestingly, soluble CD36 (sCD36) was tightly associated not only with hepatic steatosis and injury but also with inflammation. Collectively, ß-PAE exerted a positive effect against NASH by interrupting the vicious circle among oxidative stress, histanoxia and lipid accumulation, and sCD36 may be a promising non-invasive tool for NASH diagnosis.

ß-Patchoulene Ameliorates Water Transport and the Mucus Barrier in 5-Fluorouracil-Induced Intestinal Mucositis Rats via the cAMP/PKA/CREB Signaling Pathway.

Intestinal mucositis (IM) is the main side effect observed in patients who receive cancer chemotherapy. The characteristics of ulceration, vomiting, and severe diarrhea cause patients to delay or abandon further treatment, thereby aggravating their progress. Hence, IM cannot be overlooked. ß-patchoulene (ß-PAE) is an active ingredient isolated from Pogostemon cablin (Blanco) Benth (Labiatae) and has shown a marked protective effect against gastrointestinal diseases in previous studies. However, whether ß-PAE plays a positive role in IM is still unknown. Herein, we explore the effects and the underlying mechanism of ß-PAE against 5-fluorouracil (5-FU)-induced IM in IEC-6 cells and rats. ß-PAE significantly recovered cell viability, upregulated the IM-induced rat body weight and food intake and improved the pathological diarrhea symptoms. Aquaporin is critical for regulating water fluid homeostasis, and its abnormal expression was associated with pathological diarrhea in IM. ß-PAE displayed an outstanding effect in inhibiting aquaporin 3 (AQP3) via the cAMP/protein kinase A (PKA)/cAMP-response element-binding protein (CREB) signaling pathway. Besides, inflammation-induced mucus barrier injury deteriorated water transport and aggravated diarrhea in IM-induced rats. ß-PAE's effect on suppressing inflammation and recovering the mucus barrier strengthened its regulation of water transport and thus alleviated diarrhea in IM-induced rats. In sum, ß-PAE improved IM in rats mainly by improving water transport and the mucus barrier, and these effects were correlated with its function on inhibiting the cAMP/PKA/CREB signaling pathway.

ß-patchoulene improves lipid metabolism to alleviate non-alcoholic fatty liver disease via activating AMPK signaling pathway.

Non-alcoholic fatty liver disease (NAFLD) has been a leading cause of chronic metabolic disease, seriously posing healthy burdens to the public, whereas interventions available for it are limited to date. Patchouli oil had been reported to attenuate hepatic steatosis in our previous study. ß-patchoulene (ß-PAE) is a representative component separated from patchouli oil with multiple activities, but its effect against NAFLD is still unknown. To investigate the effect and potential mechanism of ß-PAE on NAFLD, we used high fat diet (HFD) in vivo and free fatty acid (FFA) in vitro to induce hepatic steatosis in rats and L02 cells, respectively. Histological examination was evaluated via Hematoxylin-eosin and oil red O staining. The parameters for hepatic steatosis were estimated via biochemical kits, western blotting and quantitative real-time PCR. Compound C, the inhibitor of AMPK, was applied further to examine the precise mechanism of ß-PAE on NAFLD. Our results indicated that ß-PAE significantly attenuated HFD-induced weight gain, hepatic injury, lipid deposition in serum and hepatic tissue as well as FFA induced-lipid accumulation. Besides, ß-PAE markedly improved the expression of AMP-activated protein kinase (AMPK) and its downstream factors which correlate with hepatic lipid synthesis and oxidation in vivo and in vitro. Nevertheless, Compound C abrogated the benefits derived from ß-PAE in L02 cells. In conclusion, these results suggest that ß-PAE exerts AMPK agonist-like effect to regulate hepatic lipid synthesis and oxidation, eventually prevent NAFLD progression.

ß-patchoulene simultaneously ameliorated dextran sulfate sodium-induced colitis and secondary liver injury in mice via suppressing colonic leakage and flora imbalance.

Ulcerative colitis (UC) often occurs accompanied by colonic leakage and flora imbalance, resulting in secondary liver injury (SLI). SLI, in turn, aggravates UC, so the treatment of UC should not ignore it. ß-patchoulene (ß-PAE), a tricyclic sesquiterpene isolated from Pogostemon cablin, has been reported to exert a protective effect in gastrointestinal disease in our previous studies. However, its protection against UC and SLI remains unknown. Here we explored the protective effect and underlying mechanism of ß-PAE against dextran sulfate sodium-induced UC and SLI in mice. The results indicated that ß-PAE significantly reduced disease activity index, splenic index and attenuated the shortening of colonic length in UC mice. It alleviated colonic pathological changes and apoptosis through protecting tight junctions, reducing neutrophil aggregation, and inhibiting the release of pro-inflammatory cytokines and adhesion molecules. These effects of ß-PAE were associated with the inhibition of TLR4/MyD88/NF-κB and ROCK1/MLC2 signalling pathway. UC-induced colonic leakage caused abnormally high LPS levels to result in SLI, and ß-PAE markedly inhibited it. ß-PAE simultaneously ameliorated SLI with reduced biomarker levels of endotoxin exposure and hepatic inflammation. High levels of LPS were also associated with flora imbalance in UC mice. However, ß-PAE restored the diversity of gut microbiota and altered the relative abundance of characteristic flora of UC mice. Escherichia-dominated gut microbiota of UC mice was changed to Oscillospira-dominated after ß-PAE treatment. In conclusion, pharmacological effects of ß-PAE on UC and SLI were mainly contributed by suppressing colonic leakage and flora imbalance. The findings may have implications for UC treatment that not neglect the treatment of SLI.