1. Phage display for targeting PCSK9
- Author
-
Nicola Ferri
- Subjects
Phage display ,Research paper ,LPEI, linear polyethyleneimine ,Hypercholesterolemia ,GAPDH, glyceraldehyde 3-phosphate dehydrogenase ,PBS, phosphate-buffered saline ,lcsh:Medicine ,Computational biology ,CVD, cardiovascular disease ,LC, light chain ,General Biochemistry, Genetics and Molecular Biology ,PCSK9 ,BLI, bio-layer interferometry ,HDL-C, high-density lipoprotein cholesterol ,Text mining ,Fab, antibody-binding fragment ,CDR, complementarity-determining region ,MMPBSA, molecular mechanics-poison boltzmann surface area ,Medicine ,Humans ,Bacteriophages ,NS, nephrotic syndrome ,CDC, complement-dependent cytotoxicity ,lcsh:R5-920 ,Human antibody ,ADCC, antibody-dependent cellular cytotoxicity ,TG, triglyceride ,business.industry ,lcsh:R ,HC, heavy chain ,scFv, single-chain variable fragment ,General Medicine ,HNF1, hepatocyte nuclear factor 1 ,CTD, C-terminal domain ,IMAC, immobilised metal affinity chromatography ,TC, total cholesterol ,EGF-A, epidermal growth factor-like repeat A ,LDLR, low-density lipoprotein receptor ,BSA, bovine serum albumin ,LDL-C, low-density lipoprotein cholesterol ,Proprotein Convertase 9 ,HDD, hydrodynamic delivery ,business ,Cell Surface Display Techniques ,Affinity maturation ,lcsh:Medicine (General) ,PCSK9, proprotein convertase subtilisin/kexin type 9 ,mAbs, monoclonal antibodies - Abstract
Background Proprotein convertase subtilisin/kexin type 9 (PCSK9) regulates serum LDL cholesterol (LDL-C) levels by facilitating the degradation of the LDL receptor (LDLR) and is an attractive therapeutic target for hypercholesterolemia intervention. Herein, we generated a novel fully human antibody with favourable druggability by utilizing phage display-based strategy. Methods A potent single-chain variable fragment (scFv) named AP2M21 was obtained by screening a fully human scFv phage display library with hPCSK9, and performing two in vitro affinity maturation processes including CDR-targeted tailored mutagenesis and cross-cloning. Thereafter, it was transformed to a full-length Fc-silenced anti-PCSK9 antibody FAP2M21 by fusing to a modified human IgG1 Fc fragment with L234A/L235A/N297G mutations and C-terminal lysine deletion, thus eliminating its immune effector functions and mitigating mAb heterogeneity. Findings Our data showed that the generated full-length anti-PCSK9 antibody FAP2M21 binds to hPCSK9 with a KD as low as 1.42 nM, and a dramatically slow dissociation rate (koff, 4.68 × 10−6 s−1), which could be attributed to its lower binding energy (-47.51 kcal/mol) than its parent counterpart FAP2 (-30.39 kcal/mol). We verified that FAP2M21 potently inhibited PCSK9-induced reduction of LDL-C uptake in HepG2 cells, with an EC50 of 43.56 nM. Further, in hPCSK9 overexpressed C57BL/6 mice, a single tail i.v. injection of FAP2M21 at 1, 3 and 10 mg/kg, dose-dependently up-regulated hepatic LDLR levels, and concomitantly reduced serum LDL-C by 3.3% (P = 0.658, unpaired Student's t-test), 30.2% (P = 0.002, Mann-Whitney U-test) and 37.2% (P = 0.002, Mann-Whitney U-test), respectively. Interpretation FAP2M21 with potent inhibitory effect on PCSK9 may serve as a promising therapeutic agent for treating hypercholesterolemia and associated cardiovascular diseases.
- Published
- 2021