A point mutant of apolipoprotein A-I, V156K, exhibited potent anti-oxidant and anti-atherosclerotic activity in hypercholesterolemic C57BL/6 mice.
In our previous study, two point mutants of apolipoprotein A-I, designated V156K and A158E, revealed peculiar characteristics in their lipid-free and lipid-bound states. In order to determine the putative therapeutic potential of these mutants, several in vitro and in vivo evaluations were conducted. In the lipid-free state, V156K showed more profound antioxidant activity against LDL oxidation than did the wildtype (WT) or A158E variants in an in vitro assay. In the lipid-bound state, V156K-rHDL showed an enhanced cholesterol delivery activity to HepG2 cells in a time-dependent manner, as compared to WT-rHDL, A158E-rHDL, and R173C-rHDL. We assessed the physiological activities of the mutants in circulation, using hypercholesterolemic mice (C57BL6/J). Palmitoyloleoyl phosphatidylcholine (POPC)-rHDL preparations containing each of the apoA-I variants were injected into the mice at a dosage of 30 mg of apoA-I/kg of body weight. Forty eight hours after injection, the sera of the V156K-rHDL injected group showed the most potent antioxidant abilities in the ferric acid removal assay. The V156K-rHDL- or R173C-rHDL-injected mice showed no atherosclerotic lesions and manifested striking increases in their serum apo-E levels, as compared to the mice injected with WT-rHDL or A158E-rHDL. In conclusion, V156K-rHDL exhibited the most pronounced antioxidant activity and anti-atherosclerotic activity, both in vitro and in vivo. These results support the notion that HDL-therapy may prove beneficial due to its capacity to induce accelerated cholesterol excretion, as well as its enhanced antioxidant and anti-inflammatory effects and lesion regression effect.
Cho
Kyung-Hyun
KH
School of Biotechnology and Aging-associated Vascular Disease Research Center, Yeungnam University, Gyeongsan 712-749, Korea. chok@yu.ac.kr
Park
Sun-Hyun
SH
Han
Jong-Min
JM
Kim
Hyoung-Chin
HC
Chung
Young-Jin
YJ
Choi
Inho
I
Kim
Jae-Ryong
JR
D000596:Amino Acids / Q000235:genetics*; D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D016632:Apolipoprotein A-I / Q000235:genetics*; D050197:Atherosclerosis / Q000473:pathology*; D001692:Biological Transport / Q000187:drug effects; D045744:Cell Line, Tumor; D002784:Cholesterol / Q000378:metabolism; D003300:Copper / Q000494:pharmacology; D006801:Humans; D006937:Hypercholesterolemia / Q000139:chemically induced / Q000473:pathology*; D008075:Lipoproteins, HDL / Q000097:blood; D008077:Lipoproteins, LDL / Q000097:blood; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D010084:Oxidation-Reduction / Q000187:drug effects; D017354:Point Mutation / Q000235:genetics*; D011994:Recombinant Proteins / Q000097:blood
D000596:Amino Acids; D000975:Antioxidants; D016632:Apolipoprotein A-I; D008075:Lipoproteins, HDL; D008077:Lipoproteins, LDL; D011994:Recombinant Proteins; D003300:Copper; D002784:Cholesterol