Blockade of glycolysis-dependent contraction by oroxylin a via inhibition of lactate dehydrogenase-a in hepatic stellate cells

Feixia Wang,Shanzhong Tan,Mengmeng Li,Jiangjuan Shao,Hai Ding,Feng Zhang,Ling Wang,Shizhong Zheng,Qinglong Guo,Yan Jia,Anping Chen

doi:10.1186/s12964-019-0324-8

Abstract

BackgroundContraction of hepatic stellate cells (HSCs) plays an important role in the pathogenesis of liver fibrosis by regulating sinusoidal blood flow and extracellular matrix remodeling. Here, we investigated how HSC contraction was affected by the natural compound oroxylin A, and elucidated the underlying mechanism.MethodsCell contraction and glycolysis were examined in cultured human HSCs and mouse liver fibrosis model upon oroxylin A intervention using diversified cellular and molecular assays, as well as genetic approaches.ResultsOroxylin A limited HSC contraction associated with inhibiting myosin light chain 2 phosphorylation. Oroxylin A blocked aerobic glycolysis in HSCs evidenced by reduction in glucose uptake and consumption and lactate production. Oroxylin A also decreased extracellular acidification rate and inhibited the expression and activity of glycolysis rate-limiting enzymes (hexose kinase 2, phosphofructokinase 1 and pyruvate kinas type M2) in HSCs. Then, we identified that oroxylin A blockade of aerobic glycolysis contributed to inhibition of HSC contraction. Furthermore, oroxylin A inhibited the expression and activity of lactate dehydrogenase-A (LDH-A) in HSCs, which was required for oroxylin A blockade of glycolysis and suppression of contraction. Oral administration of oroxylin A at 40 mg/kg reduced liver injury and fibrosis, and inhibited HSC glycolysis and contraction in mice with carbon tetrachloride-induced hepatic fibrosis. However, adenovirus-mediated overexpression of LDH-A significantly counteracted the oroxylin A’s effects in fibrotic mice.ConclusionsBlockade of aerobic glycolysis by oroxylin A via inhibition of LDH-A reduced HSC contraction and attenuated liver fibrosis, suggesting LDH-A as a promising target for intervention of hepatic fibrosis.

Highlights

Contraction of hepatic stellate cells (HSCs) plays an important role in the pathogenesis of liver fibrosis by regulating sinusoidal blood flow and extracellular matrix remodeling
The following primary antibodies were used for Western blot analysis in current study: antibodies against hexokinase 2 (HK2), phosphofructokinase 1 (PFK1), pyruvate kinas type M2 (PKM2), lactate dehydrogenase-A (LDH-A), β-actin and glyceraldehyde phosphate dehydrogenase (GAPDH) were obtained from Proteintech Group (Chicago, IL, USA); antibodies against p-MLC2Ser19, myosin light chain 2 (MLC2), α-smooth muscle actin (α-SMA), fibronectin and α1(I) procollagen were obtained from Cell Signaling Technology (Danvers, MA, USA)
Oroxylin a inhibits lactate dehydrogenase (LDH)-A in HSCs Given that LDH-A is a central player in glycolysis and has a multifunctional role in cell biology [25], we focused on the regulation of LDH-A by oroxylin A in HSCs

Summary

Introduction

Contraction of hepatic stellate cells (HSCs) plays an important role in the pathogenesis of liver fibrosis by regulating sinusoidal blood flow and extracellular matrix remodeling. Cell contraction is a highly energy-consuming process. It has been well established that a key metabolic hallmark of cancer cells is aerobic glycolysis, termed Warburg effect [8]. High expression or activity of LDH-A allows for rapid glycolysis flux so as to meet the energy demands of rapidly proliferating cells [11]. Recent evidence suggests that the activated HSCs are similar to the highly proliferative cancer cells with regard to their biosynthetic and bioenergetic requirements [12]. Aerobic glycolysis is a striking metabolic phenotype of activated HSCs during liver fibrosis [12]. Little is known about the role of aerobic glycolysis in controlling of HSC contraction

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