Naringenin Attenuates Non-Alcoholic Fatty Liver Disease by Enhancing Energy Expenditure and Regulating Autophagy via AMPK

Abstract

Background: The prevalence of non-alcoholic fatty liver disease (NAFLD) keeps growing recently.Purpose: To investigate the effects and mechanisms of naringenin (NAR) on NAFLD.Methods: High-fat diet (HFD)-induced NAFLD rats were orally administered with NAR at 10, 30, and 90 mg/kg for 2 weeks. The serum level of triglyceride (TG), total cholesterol (TC), glutamic-oxaloacetic transaminase (AST), and glutamic-pyruvic transaminase (ALT) was measured. The hepatic histology was detected by H&E and oil red O staining. L02 and Huh-7 cells were induced by sodium oleate to establish a NAFLD cell model. The effects of NAR on lipid accumulation were detected by oil red O staining. The glucose uptake and ATP content of 3T3-L1 adipocytes and C2C12 myotubes were measured. The expression of proteins of the AMPK signaling pathway in 3T3-L1 adipocytes and C2C12 myotubes was assessed by Western blotting. The mitochondrial biogenesis of 3T3-L1 adipocytes and C2C12 myotubes was measured by mitotracker orange staining and Western blotting. The biomarkers of autophagy were detected by Western blotting and immunofluorescence. The binding of NAR to AMPKγ1 was analyzed by molecular docking. Chloroquine and compound C were employed to block autophagic flux and AMPK, respectively.Results: NAR alleviated HFD-induced NAFLD in rats at 10, 30, and 90 mg/kg. NAR attenuated lipid accumulation in L02 and Huh-7 cells at 0.7, 2.2, 6.7, and 20 μM. NAR increased glucose uptake, decreased the ATP content, activated the CaMKKβ/AMPK/ACC pathway, and enhanced the mitochondrial biogenesis in 3T3-L1 adipocytes and C2C12 myotubes. NAR increased autophagy and promoted the initiation of autophagic flux in 3T3-L1 preadipocytes and C2C12 myoblasts, while it inhibited autophagy in NAFLD rats, 3T3-L1 adipocytes, and C2C12 myotubes. Molecular docking showed that NAR binds to AMPKγ1. Compound C blocked effects of NAR on lipid accumulation and autophagy in L02 cells.Conclusion: NAR alleviates NAFLD by increasing energy expenditure and regulating autophagy via activating AMPK directly and indirectly. The direct binding of NAR and AMPKγ1 needs further validation.

Anti-adipogenic effect of the flavonoids through the activation of AMPK in palmitate (PA)-treated HepG2 cells

“…An in silico previous study reported that kaemferide is a promising AMPK activator [ 8 ]. Naringenin has shown an anti-adipogenic effect by binding to the AMP binding sites of the γ-subunit as the agonists of AMPK [ 9 ]. In the present study, molecular docking analysis showed that the flavonoids activate AMPK directly as positive modulators by interacting with the R groups of the CBS domains in the γ-subunit of AMPK.…”

“…AMP binding to the γ-subunit stimulates Thr172 phosphorylation by the upstream kinases, including liver kinase B1 (LKB1) and calcium/calmodulin-dependent protein kinase kinase-β (CaMKKβ) [ 7 ]. Various in silico studies showed that polyphenols act as positive modulators by interacting with the γ-subunit of AMPK, similar to AMP [ 8 9 ]. Accordingly, a direct activator of AMPK that would mimic the mechanism of AMP might be a suitable therapeutic strategy against adipogenesis.…”

Naringin ameliorates motor dysfunction and exerts neuroprotective role against vanadium-induced neurotoxicity

“…Group A (Control: normal saline), Group B (Naringin at 30 mg/kg BW intraperitoneally), Group C (Naringin at 30 mg/kg BW and Vanadium at 10mg/kg BW), Group D (Vanadium at 10mg/kg BW intraperitoneally). The duration of the experiment was 14 days [7] , [8] .…”

Could Naringenin Participate as a Regulator of Obesity and Satiety?

“…NAR has also been shown to exert hepatoprotective effects in vivo [ 42 , 65 ] that can prevent the development of MAFLD, which is frequently associated with obesity and MetS. Such effects focus on decreasing hepatic enzyme activity and hindering TG and cholesterol deposits, which can be macroscopically and histologically evident [ 66 ].…”

“…Most in vivo and in vitro studies describe a dose-dependent effect of NAR [ 19 , 42 , 87 ], still, its use has been studied in vivo at low doses (25 mg/kg body weight) [ 19 ] in a short period of time (2 days, intraperitoneal) [ 102 ] with positive results (see Table 1 ), which may support its use as a dietary supplement [ 65 ]. It is also important to consider that the documented effects regarding NAR are mainly preventive, protective and related to an improvement, but are not curative.…”