Open AccessChylomicron accelerates C3 tick‐over by regulating the role of Factor H, leading to overproduction of acylation stimulating protein
Author(s) -
Fujita Takayuki,
Fujioka Takayuki,
Murakami Tetsuo,
Satomura Atsushi,
Fuke Yoshinobu,
Matsumoto Koichi
Publication year - 2007
Publication title -
journal of clinical laboratory analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.536
H-Index - 50
eISSN - 1098-2825
pISSN - 0887-8013
DOI - 10.1002/jcla.20158
Subject(s) - overproduction , chylomicron , acylation , chemistry , biochemistry , catalysis , lipoprotein , very low density lipoprotein , cholesterol , enzyme
Acylation stimulating protein (ASP) is a fragment of the third component of complement (C3) that is generated in the presence of chylomicron, and plays a role in the synthesis of triacylglycerol by transporting free fatty acids into adipocytes. However, the precise mechanism of ASP generation, especially the role of chylomicron in ASP generation, is unknown. We examined the mechanism through which chylomicron induces ASP generation. Ultracentrifugationally separated chylomicron was incubated with normal human serum (NHS) under various conditions, and the amounts of complement activation products and ASP in the incubation mixture were determined by enzyme‐linked immunosorbent assay (ELISA). Upon incubation of NHS with various amounts of chylomicron for 120 min, ASP was generated in a dose‐dependent manner. The time course of the production of ASP was similar to the time course of the C3 tick‐over phenomenon that occurred by depletion of factor H from the serum. The complement activation induced by chylomicron was different from the usual complement activation that occurs under the regulation of factor H and factor I with respect to the time course and the amount of ASP produced. Our results indicate that chylomicron accelerates C3 tick‐over by regulating the role of factor H, leading to the overproduction of ASP. J. Clin. Lab. Anal. 21:14–23, 2007. © 2007 Wiley‐Liss, Inc.