title: The hypolipidemic effect of cilostazol can be mediated by regulation of hepatic low-density lipoprotein receptor-related protein 1 (LRP1) expression.
abstract: OBJECTIVE
  Cilostazol, a selective phosphodiesterase 3 (PDE3) inhibitor, is a vasodilator and an anti-thrombotic agent. The mechanism whereby cilostazol reduces plasma triglyceride is not completely understood. Here we investigated the effect of cilostazol on a remnant lipoprotein receptor, low-density lipoprotein receptor-related protein 1 (LRP1), which has been reported to play an essential role in clearance of circulating triglyceride in the liver.
  
  
  METHODS
  Total cellular expression, and functional and transcriptional regulation of LRP1 were analyzed in human hepatocarcinoma cell lines incubated with cilostazol. Also, C57BL/6 mice were subjected to high-fat diet (60% kcal) and cilostazol (30 mg/kg) treatment for 10 weeks.
  
  
  RESULTS
  Cilostazol increased both mRNA and protein expression of LRP1 in HepG2 and Hep3B cells. In addition, enhanced transcriptional activity of the LRP1 promoter containing a peroxisome proliferator response element (PPRE) was observed after cilostazol exposure. Cilostazol treatment enhanced the uptake of lipidated apoE3, and this effect was abolished when LRP1 was silenced by siRNA knockdown. High-fat diet induced hyperglycemia with high level of plasma triglycerides, and reduced hepatic LRP1 expression in mice. Treatment with cilostazol for the same period of time, however, successfully prevented this down-regulation of LRP1 expression and reduced plasma triglycerides.
  
  
  CONCLUSIONS
  Taken together, our results demonstrated that cilostazol enhances LRP1 expression in liver by activating PPARγ through the PPRE in the LRP1 promoter. Increased hepatic LRP1 may be essential for the reduction of circulating triglycerides brought about by cilostazol.
authors.affiliation: Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Hyung Jun
authors.initials: HJ
authors.lastname: Kim
authors.forename: Jae Hoon
authors.initials: JH
authors.lastname: Moon
authors.forename: Hyun Min
authors.initials: HM
authors.lastname: Kim
authors.forename: Mi Ra
authors.initials: MR
authors.lastname: Yun
authors.forename: Byung Hun
authors.initials: BH
authors.lastname: Jeon
authors.forename: Byungwan
authors.initials: B
authors.lastname: Lee
authors.forename: Eun Seok
authors.initials: ES
authors.lastname: Kang
authors.forename: Hyun Chul
authors.initials: HC
authors.lastname: Lee
authors.forename: Bong Soo
authors.initials: BS
authors.lastname: Cha
mesh_terms: D000818:Animals; D053318:Apolipoprotein E3 / Q000378:metabolism; D015153:Blotting, Western; D006528:Carcinoma, Hepatocellular / Q000378:metabolism; D045744:Cell Line, Tumor; D000077407:Cilostazol; D059305:Diet, High-Fat; D015536:Down-Regulation; D015972:Gene Expression Regulation, Neoplastic; D020868:Gene Silencing; D056945:Hep G2 Cells; D006801:Humans; D000960:Hypolipidemic Agents / Q000494:pharmacology*; D008099:Liver / Q000378:metabolism*; D008113:Liver Neoplasms / Q000378:metabolism; D026503:Low Density Lipoprotein Receptor-Related Protein-1 / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D060888:Real-Time Polymerase Chain Reaction; D013777:Tetrazoles / Q000494:pharmacology*; D014158:Transcription, Genetic; D014280:Triglycerides / Q000097:blood*
chemical_list: D053318:Apolipoprotein E3; D000960:Hypolipidemic Agents; C475476:LRP1 protein, human; D026503:Low Density Lipoprotein Receptor-Related Protein-1; D013777:Tetrazoles; D014280:Triglycerides; D000077407:Cilostazol
keywords: 1,2-dimyristoyl-sn-glycero-3-phosphocholin; 2-chloro-5-nitrobenzanilide; 3,3′-Diaminobenzidine; 4′,6-diamidino-2-phenylindole; Atherosclerosis; CR; DAB; DAPI; DMPC; DMSO; DNase; Dyslipidemia; GW9662; Glut 4; H&E; HDL; HSPG; HUVEC; IPGTT; LDL; LPL; LRP1; MEM; PCR; PDE3; PPAR-γ; PPARγ; PPRE; Polymerase chain reaction; RNase; RT; RT-PCR; Reverse transcriptase; STZ; TG; VLDL; apoE; apolipoprotein E; chylomicron remnants; dNTP; deoxyriboNTP; deoxyribonuclease; dimethyl sulfoxide; glucose transporter 4; hematoxylin and eosin; heparan sulfate proteoglycans; high-density lipoprotein; human umbilical vein endothelia cell; i.p. glucose tolerance test; lipoprotein lipase; low-density lipoprotein; low-density lipoprotein receptor-related protein 1; minimum essential medium; peroxisome proliferator activated receptor-γ; peroxisome proliferator response element; phosphodiesterase 3; real-time polymerase chain reaction; ribonuclease; siRNA; small interfering RNA;PKA, protein kinase A; streptozotocin; triglyceride; very low-density lipoproteins