Androsin alleviates non-alcoholic fatty liver disease by activating autophagy and attenuating de novo lipogenesis

Abstract

Background: Non-alcoholic fatty liver disease (NAFLD) is a chronic liver disease with therapeutic options on the horizon. Picrorhiza kurroa, enriched with iridoid glycosides like picroside I and picroside II is known for its hepatoprotective activity and anti-inflammatory properties. Androsin, the other phytochemical present in P. kurroa has been shown to have anti-inflammatory and anti-asthmatic properties. However, its role in NAFLD is yet to be investigated.

Purpose: This study aims to identify the potent hepatoprotective agent from P. kurroa that can attenuate NAFLD in HFrD-fed ApoE^-/- mice, and elucidate the underlying mechanisms governing its effects.

Methods: Classical purification methods were used to isolate seven compounds, including picroside I, picroside II and androsin from the roots of P. kurroa. NAFLD-induced ApoE^-/- mice were administered orally with either picroside I, picroside II, or androsin for 7 weeks. Animals were scanned non-invasively by ultrasonography at 1^st and 14^th week. Gross histomorphometry was examined by HE and Sirius red staining. mRNA transcript and protein profile associated with autophagy, lipogenesis, inflammation, and fibrosis was done through RT-PCR and Western blot analysis.

Results: In-vitro and in-vivo studies revealed that among the seven evaluated compounds, androsin shows the most potent in-vitro activity. Oral dosing of androsin (10 mg/kg) protected the liver against HFrD-induced NAFLD in ApoE^-/- mice model. Biochemical analysis revealed a reduction in ALT and AST enzymes and a significant reduction in cholesterol levels. Hepatocyte ballooning, hepatic lipid deposition, inflammation, and fibrosis were reduced. Androsin treatment significantly reduced fibrosis (α-SMA, collagens, TGF-β) and inflammation (ILs, TNF-α, NFκB) in ApoE^-/- mice. Mechanistically, androsin activated AMPKα and down-regulated the expression of SREBP-1c, resulting in ameliorating hepatic lipogenesis.

Conclusion: Our results support autophagy as one of the therapeutic strategies to reduce steatosis and hepatic damage. We found that androsin treatment significantly ameliorated hepatic steatosis, serum lipid levels, and hepatic injury in ApoE^-/- induced by HFrD. Androsin administration mitigated lipogenesis by inhibiting SREBP1c/FASN pathway and activating autophagy through AMPKα/PI3K/Beclin1/LC3 pathway.

Keywords: Androsin; ApoE-/-; NAFLD; Picrorhiza kurroa; autophagy; de novo lipogenesis.