title: Identification of a new functional domain in angiopoietin-like 3 (ANGPTL3) and angiopoietin-like 4 (ANGPTL4) involved in binding and inhibition of lipoprotein lipase (LPL).
abstract: Angiopoietin-like 3 (ANGPTL3) and angiopoietin-like 4 (ANGPTL4) are secreted proteins that regulate triglyceride (TG) metabolism in part by inhibiting lipoprotein lipase (LPL). Recently, we showed that treatment of wild-type mice with monoclonal antibody (mAb) 14D12, specific for ANGPTL4, recapitulated the Angptl4 knock-out (-/-) mouse phenotype of reduced serum TG levels. In the present study, we mapped the region of mouse ANGPTL4 recognized by mAb 14D12 to amino acids Gln(29)-His(53), which we designate as specific epitope 1 (SE1). The 14D12 mAb prevented binding of ANGPTL4 with LPL, consistent with its ability to neutralize the LPL-inhibitory activity of ANGPTL4. Alignment of all angiopoietin family members revealed that a sequence similar to ANGPTL4 SE1 was present only in ANGPTL3, corresponding to amino acids Glu(32)-His(55). We produced a mouse mAb against this SE1-like region in ANGPTL3. This mAb, designated 5.50.3, inhibited the binding of ANGPTL3 to LPL and neutralized ANGPTL3-mediated inhibition of LPL activity in vitro. Treatment of wild-type as well as hyperlipidemic mice with mAb 5.50.3 resulted in reduced serum TG levels, recapitulating the lipid phenotype found in Angptl3(-/-) mice. These results show that the SE1 region of ANGPTL3 and ANGPTL4 functions as a domain important for binding LPL and inhibiting its activity in vitro and in vivo. Moreover, these results demonstrate that therapeutic antibodies that neutralize ANGPTL4 and ANGPTL3 may be useful for treatment of some forms of hyperlipidemia.
authors.affiliation: Departments of Biotherapeutics Lexicon Pharmaceuticals Inc., The Woodlands, Texas 77381. Electronic address: elee@lexpharma.com.
authors.forename: E-Chiang
authors.initials: EC
authors.lastname: Lee
authors.affiliation: Pharmaceutical Biology Lexicon Pharmaceuticals Inc., The Woodlands, Texas 77381.
authors.forename: Urvi
authors.initials: U
authors.lastname: Desai
authors.affiliation: Departments of Biotherapeutics Lexicon Pharmaceuticals Inc., The Woodlands, Texas 77381.
authors.forename: Gennady
authors.initials: G
authors.lastname: Gololobov
authors.affiliation: Departments of Biotherapeutics Lexicon Pharmaceuticals Inc., The Woodlands, Texas 77381.
authors.forename: Seokjoo
authors.initials: S
authors.lastname: Hong
authors.affiliation: Departments of Biotherapeutics Lexicon Pharmaceuticals Inc., The Woodlands, Texas 77381.
authors.forename: Xiao
authors.initials: X
authors.lastname: Feng
authors.affiliation: Pharmaceutical Discovery Lexicon Pharmaceuticals Inc., The Woodlands, Texas 77381.
authors.forename: Xuan-Chuan
authors.initials: XC
authors.lastname: Yu
authors.affiliation: Pharmaceutical Biology Lexicon Pharmaceuticals Inc., The Woodlands, Texas 77381.
authors.forename: Jason
authors.initials: J
authors.lastname: Gay
authors.affiliation: Pharmaceutical Biology Lexicon Pharmaceuticals Inc., The Woodlands, Texas 77381.
authors.forename: Nat
authors.initials: N
authors.lastname: Wilganowski
authors.affiliation: Departments of Biotherapeutics Lexicon Pharmaceuticals Inc., The Woodlands, Texas 77381.
authors.forename: Cuihua
authors.initials: C
authors.lastname: Gao
authors.affiliation: Departments of Biotherapeutics Lexicon Pharmaceuticals Inc., The Woodlands, Texas 77381.
authors.forename: Ling-Ling
authors.initials: LL
authors.lastname: Du
authors.affiliation: Departments of Biotherapeutics Lexicon Pharmaceuticals Inc., The Woodlands, Texas 77381.
authors.forename: Joan
authors.initials: J
authors.lastname: Chen
authors.affiliation: Molecular Biology, Lexicon Pharmaceuticals Inc., The Woodlands, Texas 77381.
authors.forename: Yi
authors.initials: Y
authors.lastname: Hu
authors.affiliation: Molecular Biology, Lexicon Pharmaceuticals Inc., The Woodlands, Texas 77381.
authors.forename: Sharon
authors.initials: S
authors.lastname: Zhao
authors.affiliation: Departments of Biotherapeutics Lexicon Pharmaceuticals Inc., The Woodlands, Texas 77381.
authors.forename: Laura
authors.initials: L
authors.lastname: Kirkpatrick
authors.affiliation: Pharmaceutical Biology Lexicon Pharmaceuticals Inc., The Woodlands, Texas 77381.
authors.forename: Matthias
authors.initials: M
authors.lastname: Schneider
authors.affiliation: Departments of Biotherapeutics Lexicon Pharmaceuticals Inc., The Woodlands, Texas 77381; Pharmaceutical Biology Lexicon Pharmaceuticals Inc., The Woodlands, Texas 77381; Pharmaceutical Discovery Lexicon Pharmaceuticals Inc., The Woodlands, Texas 77381; Molecular Biology, Lexicon Pharmaceuticals Inc., The Woodlands, Texas 77381.
authors.forename: Brian P
authors.initials: BP
authors.lastname: Zambrowicz
authors.affiliation: Departments of Biotherapeutics Lexicon Pharmaceuticals Inc., The Woodlands, Texas 77381.
authors.forename: Greg
authors.initials: G
authors.lastname: Landes
authors.affiliation: Pharmaceutical Biology Lexicon Pharmaceuticals Inc., The Woodlands, Texas 77381.
authors.forename: David R
authors.initials: DR
authors.lastname: Powell
authors.affiliation: Departments of Biotherapeutics Lexicon Pharmaceuticals Inc., The Woodlands, Texas 77381. Electronic address: wsonnenburg@lexpharma.com.
authors.forename: William K
authors.initials: WK
authors.lastname: Sonnenburg