ApoA-I mutants V156K and R173C promote anti-inflammatory function and antioxidant activities.
BACKGROUND
Two mutants of apolipoprotein (apo) A-I, V156K and A158E, showed markedly different structural and functional properties in lipid-free and lipid-bound states in the authors' earlier report. The physiological activities of these mutants were compared with the wild-type (WT) and R173C mutant using in vitro and in vivo experiments.


METHODS
A reconstituted high-density lipoprotein (rHDL) with palmitoyloleoyl phosphatidylcholine (POPC), combined with each of the apoA-I variants, was injected into the tail-veins of hypercholesterolaemic mice (C57BL6/J), which had been fed a high cholesterol and high fat (HCHF; 0.5% cholesterol, 15% lard, 0.1% sodium cholate) diet for 23 weeks, once at 0 h and then every 24 h, at a dosage of 30 mg apoA-I kg(-1) of body-weight.


RESULTS
The V156K-rHDL and R173C-rHDL exhibited significantly stronger anti-oxidant activity against copper-mediated low-density lipoprotein (LDL) oxidation than did A158E in an apolipoprotein state. The mice injected with WT-rHDL or A158E-rHDL showed abrupt increases in total cholesterol concentrations (47% and 38%, respectively) as compared with the levels before injection, whereas the mice injected with V156K-rHDL and R173C-rHDL did not. Injection with V156K-rHDL improved serum lipids and anti-oxidative activities compared with the injection of WT-rHDL. Injection of WT-rHDL or A158E-rHDL increased serum interleukin-6 (IL-6) to 90-110 pg mL(-1), whereas the injection of V156K-rHDL or R173C-rHDL increased serum IL-6 to 17-25 pg mL(-1) only.


CONCLUSIONS
The V156K-rHDL and R173C-rHDL displayed potent beneficial effects, including anti-oxidant and anti-inflammatory activity from both in vitro and in vivo evaluations, whereas the WT-rHDL and A158E-rHDL did not.
Cho
K H
KH
School of Biotechnology, Yeungnam University, Gyeongsan, South Korea. chok@yu.ac.kr
Park
S H
SH
Han
J M
JM
Kim
H C
HC
Choi
Y K
YK
Choi
I
I
D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D016632:Apolipoprotein A-I / Q000235:genetics / Q000378:metabolism*; D016207:Cytokines / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D008075:Lipoproteins, HDL / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D007862:Phosphatidylcholine-Sterol O-Acyltransferase / Q000378:metabolism; D017354:Point Mutation; D011994:Recombinant Proteins
D000975:Antioxidants; D016632:Apolipoprotein A-I; D016207:Cytokines; D008075:Lipoproteins, HDL; D011994:Recombinant Proteins; D007862:Phosphatidylcholine-Sterol O-Acyltransferase