Complete rescue of lipoprotein lipase-deficient mice by somatic gene transfer of the naturally occurring LPLS447X beneficial mutation.
The naturally occurring human lipoprotein lipase S447X variant (LPLS447X) exemplifies a gain-of function mutation with significant benefits including decreased plasma triglycerides (TG), increased high-density lipoprotein (HDL) cholesterol, and reduced risk of coronary artery disease. The S447X variant may be associated with higher LPL catalytic activity; however, in vitro data supporting this hypothesis are contradictory. We wanted to investigate the in vivo mechanism by which the LPLS447X variant improves the lipid profile of S447X carriers. We conducted a functional assessment of human LPLS447X compared with LPLWT in mice. LPL variants were compared in the absence of endogenous mouse LPL in newborn LPL(-/-) mice by adenoviral-mediated gene transfer. LPL(-/-) mice normally exhibit severe hypertriglyceridemia and die within 48 hours of birth. LPLWT gene transfer prolonged the survival of mice up to 21 days. In contrast, LPLS447X completely rescued 95% of the mice to adulthood and increased LPL catalytic activity in postheparin plasma 2.1-fold compared with LPLWT at day 3 (P=0.003). LPLS447X also reduced plasma TG 99% from baseline (P<0.001), 2-fold more than LPLWT, (P<0.01) and increased plasma HDL cholesterol 2.9-fold higher than LPLWT (P<0.01). These data provide in vivo evidence that the increased catalytic activity of LPLS447X improves plasma TG clearance and increases the HDL cholesterol pool compared with LPLWT.
Department of Medical Genetics, University of British Columbia, Centre for Molecular Medicine and Therapeutics, Vancouver, Canada.
Colin J D
CJ
Ross
Guoqing
G
Liu
Jan Albert
JA
Kuivenhoven
Jaap
J
Twisk
Jaap
J
Rip
Willemijn
W
van Dop
Katherine J D Ashbourne
KJ
Excoffon
Suzanne M E
SM
Lewis
John J
JJ
Kastelein
Michael R
MR
Hayden
D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D000831:Animals, Newborn; D016466:CHO Cells; D008076:Cholesterol, HDL / Q000097:blood; D006224:Cricetinae; D005298:Fertility; D018014:Gene Transfer Techniques; D015316:Genetic Therapy / Q000379:methods*; D006801:Humans; D015228:Hypertriglyceridemia / Q000097:blood / Q000235:genetics / Q000628:therapy*; D007774:Lactation; D008071:Lipoprotein Lipase / Q000235:genetics* / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D008817:Mice, Mutant Strains; D017354:Point Mutation; D012333:RNA, Messenger / Q000032:analysis; D014280:Triglycerides / Q000097:blood
D008076:Cholesterol, HDL; D012333:RNA, Messenger; D014280:Triglycerides; D008071:Lipoprotein Lipase