Rugulatory effect of prostaglandin EP4 receptor on LDL uptake : in vitro pilot study

Abstract

Prostaglandin E receptor subtype 4 (EP4) is a widely-distributed receptor that interacts with prostaglandin E2 (PGE2), an essential homeostatic factor, that mediates inflammatory responses. While its role in the realm of inflammation is much better documented, its apparent ability to regulate lipid uptake to adipose tissues and skeletal muscles has barely been researched.

This pilot study primarily aimed to assess the lipoprotein regulatory effects of EP4 and to develop an in vitro cell model that would adequately allow for the study of EP4. This study also made an overall evaluation on the methods and techniques used here and their subsequent appropriateness in future studies.

Lipoprotein profile and their receptors from EP4 knockout mice were analysed and in vitro cell model was done by using small-interfering RNA (siRNA) on HepG2 cell line. Elevated lipoproteins in plasma and reduced expression of lowdensity lipoprotein receptors (LDL-R) in liver tissue had been demonstrated in the absence of EP4 in this pilot study. In addition, in vitro hepatocellular model with the absence of EP4 had also shown a weak uptake efficacy on low-density lipoprotein.

Results of this pilot study suggest that there is justification for conducting further studies to investigate the basic science of EP4 in lipoprotein metabolism, particularly on its interaction with LDL-R. Evaluations on methods and in vitro model reported in this pilot study could be resourceful for future research design on enhancing methodological quality.