Conophylline inhibits high fat diet-induced non-alcoholic fatty liver disease in mice

PLoS One. 2019 Jan 28;14(1):e0210068. doi: 10.1371/journal.pone.0210068. eCollection 2019.

Abstract

Conophylline (CnP), a vinca alkaloid extracted from the leaves of the tropical plant Tabernaemontana divaricate, attenuates hepatic fibrosis in mice. We have previously shown that CnP inhibits non-alcoholic steatohepatitis (NASH) using a methionine-choline-deficient (MCD) diet-fed mouse model. However, little is known about the CnP mediated inhibition of hepatic steatosis in high-fat diet-induced non-alcoholic fatty liver disease (NAFLD) mouse models. CnP (0.5 and 1 μg/g/body weight) was co-administered along with a high-fat diet to male BALB/c mice. After nine weeks of administering the high-fat diet, hepatic steatosis, triglyceride, and hepatic fat metabolism-related markers were examined. Administration of a high-fat diet for 9 weeks was found to induce hepatic steatosis. CnP dose-dependently attenuated the high-fat diet-induced hepatic steatosis. The diet also attenuated hepatic peroxisome proliferator-activated receptor alpha (PPARA) mRNA levels. PPARA is known to be involved in β-oxidation. CnP upregulated the mRNA levels of hepatic PPARA and its target genes, such as carnitine palmitoyl transferase 1 (CPT1) and CPT2, in a dose-dependent manner in the liver. Furthermore, levels of hepatic β-hydroxybutyrate, which is a type of ketone body, were increased by CnP in a dose-dependent manner. Finally, CnP increased the expression of the autophagosomal marker LC3-II and decreased the expression of p62, which are known to be selectively degraded during autophagy. These results indicate that CnP inhibits hepatic steatosis through the stimulation of β-oxidation and autophagy in the liver. Therefore, CnP might prove to be a suitable therapeutic target for NAFLD.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Autophagy / drug effects
  • Carnitine O-Palmitoyltransferase / genetics
  • Carnitine O-Palmitoyltransferase / metabolism
  • Diet, High-Fat / adverse effects*
  • Fatty Liver / etiology
  • Fatty Liver / prevention & control*
  • Gene Expression Regulation / drug effects
  • Liver / drug effects
  • Liver / metabolism
  • Liver / pathology
  • Male
  • Mice, Inbred BALB C
  • Non-alcoholic Fatty Liver Disease / etiology
  • Non-alcoholic Fatty Liver Disease / prevention & control*
  • PPAR alpha / genetics
  • PPAR alpha / metabolism
  • Vinca Alkaloids / pharmacology*

Substances

  • PPAR alpha
  • Ppara protein, mouse
  • Vinca Alkaloids
  • conophylline
  • Carnitine O-Palmitoyltransferase

Grants and funding

This work was supported by the Program for the Strategic Research Foundation at Private Universities 2011-2015 (S1101027 to M.Y.) from the Ministry of Education, Culture, Sports, Science, and Technology in Japan (MEXT). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.