Engineered red blood cells carrying PCSK9 inhibitors persistently lower LDL and prevent obesity

PLoS One. 2021 Nov 3;16(11):e0259353. doi: 10.1371/journal.pone.0259353. eCollection 2021.

Abstract

Low plasma levels of Proprotein Convertase Subtilisin/Kexin 9 (PCSK9) are associated with decreased low-density lipoprotein (LDL) cholesterol and a reduced risk of cardiovascular disease. PCSK9 binds to the epidermal growth factor-like repeat A (EGFA) domain of LDL receptors (LDLR), very low-density lipoprotein receptors (VLDLR), apolipoprotein E receptor 2 (ApoER2), and lipoprotein receptor-related protein 1 (LRP1) and accelerates their degradation, thus acting as a key regulator of lipid metabolism. Antibody and RNAi-based PCSK9 inhibitor treatments lower cholesterol and prevent cardiovascular incidents in patients, but their high-cost hampers market penetration. We sought to develop a safe, long-term and one-time solution to treat hyperlipidemia. We created a cDNA encoding a chimeric protein in which the extracellular N- terminus of red blood cells (RBCs) specific glycophorin A was fused to the LDLR EGFA domain and introduced this gene into mouse bone marrow hematopoietic stem and progenitor cells (HSPCs). Following transplantation into irradiated mice, the animals produced RBCs with the EGFA domain (EGFA-GPA RBCs) displayed on their surface. These animals showed significantly reduced plasma PCSK9 (66.5% decrease) and reduced LDL levels (40% decrease) for as long as 12 months post-transplantation. Furthermore, the EGFA- GPA mice remained lean for life and maintained normal body weight under a high-fat diet. Hematopoietic stem cell gene therapy can generate red blood cells expressing an EGFA-glycophorin A chimeric protein as a practical and long-term strategy for treating chronic hyperlipidemia and obesity.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Body Weight
  • Cells, Cultured
  • Cholesterol, LDL / blood*
  • Diet, High-Fat / adverse effects
  • Down-Regulation*
  • Erythrocytes / metabolism
  • Female
  • Genetic Engineering
  • Glycophorins / chemistry
  • Glycophorins / genetics*
  • HEK293 Cells
  • Humans
  • Hyperlipidemias / chemically induced
  • Hyperlipidemias / metabolism
  • Hyperlipidemias / prevention & control*
  • Mice
  • Pregnancy
  • Proprotein Convertase 9 / blood*
  • Receptors, LDL / chemistry
  • Receptors, LDL / genetics*
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Stem Cell Transplantation
  • Transduction, Genetic

Substances

  • Cholesterol, LDL
  • Glycophorins
  • LDLR protein, human
  • Receptors, LDL
  • Recombinant Fusion Proteins
  • Pcsk9 protein, mouse
  • Proprotein Convertase 9