Abstract 101: Reconstituted High-density Lipoprotein - More Than the Sum of Its Parts.
Rationale Reconstituted high-density lipoprotein (rHDL, CSL-111) particles have been shown to reduce multiple organ failure following hypovolemic shock, perturb irritable bowel syndrome and, more recently, to inhibit aneurysm formation in animal models. To identify new endothelial targets of the protective effect we examined the differential changes that occur in the proteome of activated primary endothelial cells following treatment with rHDLs.
Methods Primary human endothelial cells were isolated from human umbilical cords, grown to confluence and activated with TNFα (10ng/ml), following a 4 hr incubation half the cells received rHDLs (1mg/ml, ApoAI) and the remaining cells received carrier only (10% sucrose). Protein lysates were prepared following 20 hr incubation and differential protein expression compared by scanning DiGE-2dimentional PAGE. Protein identities were confirmed using LC/MS of tryptic digests of proteins recovered from preparatory gels. Western blotting confirmed differential expression and established whether the response required the whole particle or solely the protein component of rHDLs.
Results Of the proteins identified by LC/MS which were differentially expressed in response to rHDLs, Perilipin 3 (PLPN3, 1.3 fold, p<0.003); Growth factor receptor-bound protein 2 (GRB2, 2.5 fold, p<0.003) and Vimentin (1.6 fold, p<0.007) were induced, whilst sinexin 6 (SNX6, 1.2 fold p< 0.007); Glutathione S Transferase-1 (GST-1, 1.6 fold, p<0.02) and Crystallin-zeta like (CrystZL, 1.2 fold, p<0.004) were reduced. We found that the entire lipoprotein particle was necessary for the induction of PLN3 and reduction of SNX6. Concentration of rHDL < 100μg/ml were able to modulate the maximal effect observed. However, both rHDL and lipid free ApoAI were able to induce cytokine-inhibited expression of GRB2 (rHDL>ApoAI).
Conclusion The PC component of rHDL is necessary for an acute effect on proteins involved in endosomal trafficking. Further studies are needed to understand the role this could play in the protective effect of HDL therapy.
- © 2013 by American Heart Association, Inc.