Effects of perilipin 2 antisense oligonucleotide treatment on hepatic lipid metabolism and gene expression

Abstract

Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease worldwide. We previously showed that Perilipin 2 (Plin2), a member of lipid droplet protein family, is markedly increased in fatty liver, and its reduction in the liver of diet-induced obese mice by antisense oligonucleotide (ASO) decreased steatosis and enhanced insulin sensitivity. Plin2-ASO treatment markedly suppressed lipogenic gene expression. To gain a better understanding of the biological role of Plin2 in liver, we performed microarray analysis to determine genes differentially regulated by Plin2-ASO compared with a control (scrambled) oligonucleotide (Cont). Male C57BL/6J mice on a high-fat diet were treated with Plin2- or Cont-ASO for 4 wk. Plin2-ASO decreased hepatic triglycerides, and this was associated with changes in expression of 1,363 genes. We analyzed the data for functional clustering and validated the expression of representative genes using real-time PCR. On the high-fat diet, Plin2-ASO decreased the expression of enzymes involved in fatty acid metabolism (acsl1, lipe) and steroid metabolism (hmgcr, hsd3b5, hsd17b2), suggesting that Plin2 affects hepatic lipid metabolism at the transcriptional level. Plin2-ASO also increased the expression of genes involved in regulation of hepatocyte proliferation (afp, H19), mitosis (ccna2, incenp, sgol1), and extracellular matrix (col1a1, col3a1, mmp8). Plin2-ASO had similar effects on gene expression in chow-fed mice. Together, these results indicate that Plin2 has diverse metabolic and structural roles in the liver, and its downregulation promotes hepatic fibrosis and proliferation.

Perilipin-2 Deletion Impairs Hepatic Lipid Accumulation by Interfering with Sterol Regulatory Element-binding Protein (SREBP) Activation and Altering the Hepatic Lipidome

“…Previous studies using antisense oligonucleotides targeting PLIN2 in ob/ob mice and in mice fed high fat diets suggested that SREBP target genes might be altered upon loss of PLIN2 (11,12,17). In this study, we show that both SREBP-1 and SREBP-2 target genes do indeed experience extreme alterations with loss of PLIN2.…”

“…Effects of Insulin Activity on SREBP Regulation-Insulin has been shown to exert effects on transcription and activation of SREBP-1c (12,51). Indeed, we observed impaired glucose tolerance for WT mice on WD.…”

“…This could possibly be due to incomplete knock-out of the PLIN2 protein (50) and/or differences in dietary sucrose. Additionally, the majority of studies examining the effect on hepatic TG accumulation with the loss of Plin2 have been performed in the context of leptin deficiency (11,18) and high fat diet-only feeding studies (12,17). Thus, complete characterization of the gene, protein, and lipid profile changes on control diet represents a novel area of study with regard to the role of PLIN2 in normal hepatic lipid metabolism.…”

“…Under high fat diet-induced NAFLD, PLIN2 is the predominant lipid droplet coat protein in hepatocytes in humans and rodents (10,11). Therefore, PLIN2 has become a potentially valuable therapeutic target for the treatment or prevention of NAFLD development (12).…”

Liver Perilipin 5 Expression Worsens Hepatosteatosis But Not Insulin Resistance in High Fat-Fed Mice

“…Microarray analysis of the liver from HFD fed mice treated with antisense oligonucleotides against PLIN2 showed the increase in markers of hepatic proliferation (Afp and H19) and extracellular matrix remodeling (20). Markers of inflammation and oxidative stress were also increased in the liver of PLIN5 deficient mice on HFD (12).…”