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Identification of fatty acid oxidation disorder patients with lowered acyl‐CoA thioesterase activity in human skin fibroblasts
Author(s) -
Hunt M. C.,
Ruiter J.,
Mooyer P.,
Van Roermond C. W. T.,
Ofman R.,
Ijlst L.,
Wanders R. J. A.
Publication year - 2005
Publication title -
european journal of clinical investigation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.164
H-Index - 107
eISSN - 1365-2362
pISSN - 0014-2972
DOI - 10.1111/j.1365-2362.2005.01447.x
Subject(s) - thioesterase , biochemistry , coenzyme a , acyl coa , western blot , fatty acid , biology , enzyme , acyl carrier protein , chemistry , biosynthesis , gene , reductase
Background Acyl‐CoA thioesterases are enzymes that hydrolyze acyl‐CoAs to the free fatty acid and coenzyme A (CoASH). These enzymes have been identified in several cellular compartments and are thought to regulate intracellular levels of acyl‐CoAs, free fatty acids and CoASH. However, to date no patients deficient in acyl‐CoA thioesterases have been identified. Design Acyl‐CoA thioesterase activity was measured in human skin fibroblasts. Western‐blot analysis was used to determine Type‐II acyl‐CoA thioesterase protein levels in patients. Results Acyl‐CoA thioesterase activity was found in human fibroblasts with all saturated acyl‐CoAs from C4‐CoA to C18‐CoA, with highest activity detected with lauroyl‐CoA and myristoyl‐CoA (C12‐CoA and C14‐CoA). An antibody that recognizes the major isoforms of Type‐II acyl‐CoA thioesterases precipitated the majority of acyl‐CoA thioesterase activity in fibroblasts, showing that the main thioesterase activity detected in fibroblasts is catalyzed by Type‐II thioesterases. Measurement of acyl‐CoA thioesterase activity from fibroblasts of 34 patients with putative fatty acid oxidation disorders resulted in the identification of three patients with lowered Type‐II acyl‐CoA thioesterase activity in fibroblasts. These patients also had lowered expression of Type‐II acyl‐CoA thioesterase protein in fibroblasts as judged by Western‐blot analysis. However, mutation analysis failed to identify any mutation in the coding sequences for the mitochondrial acyl‐CoA thioesterase II (MTE‐II) or the cytosolic acyl‐CoA thioesterase II (CTE‐II). Conclusions We have described three patients with lowered Type‐II acyl‐CoA thioesterase protein and activity in human skin fibroblasts, which is the first description of patients with a putative defect in acyl‐CoA thioesterases.