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Pharmacological modulation of fatty acid desaturation and of cholesterol biosynthesis in THP‐1 cells
Author(s) -
Risé P.,
Ghezzi S.,
Levati M. G.,
Mirtini R.,
Colombo C.,
Galli C.
Publication year - 2003
Publication title -
lipids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.601
H-Index - 120
eISSN - 1558-9307
pISSN - 0024-4201
DOI - 10.1007/s11745-003-1134-5
Subject(s) - simvastatin , geranylgeraniol , chemistry , nicardipine , cholesterol , biochemistry , curcumin , prenylation , arachidonic acid , reductase , linoleic acid , fatty acid , enzyme , pharmacology , biology , calcium , organic chemistry
In THP‐1 cells, simvastatin decreases, in a concentration‐dependent manner, cholesterol synthesis and increases linoleic acid (LA) conversion to its long‐chain derivatives, in particular to arachidonic acid, activating Δ6 and Δ5 fatty acid (FA) desaturases. The intermediates in cholesterol synthesis, mevalonate and geranylgeraniol, partially reverse the effects of simvastatin on the LA conversion. The aims of this work were to evaluate: (i) the correlation between cholesterol synthesis and desaturase activity and (ii) the possible involvement of protein isoprenylation in desaturase activity, assessed through pharmacological treatments. THP‐1 cells were incubated with [1‐ 14 C]LA or with [1‐ 14 C]di‐homo‐γ‐linolenic acid (DHGLA) and treated with simvastatin or with curcumin and nicardipine, inhibitors of desaturases. Curcumin was more active than nicardipine in inhibiting LA and DHGLA conversion: 20 μM curcumin, alone or with simvastatin, totally inhibited Δ6 and Δ5 desaturation steps; 10 μM nicardipine only partially inhibited the enzymes, being more active on Δ5 desaturase. Simvastatin treatment decreased the incorporation of acetate in cholesterol (−93.8%) and cholesterol esters (−70.2%), as expected. Curcumin and nicardipine also decreased cholesterol synthesis and potentiated simvastatin. Finally, the isoprenylation inhibitors (perillic acid and GGTI‐286) neither affected the conversion of LA nor inhibited the Δ5 desaturase activity. In conclusion, our results indicate that there is no direct relationship between cholesterol synthesis and desaturase activity. In fact, simvastatin decreased cholesterol synthesis and enhanced LA conversion (mainly Δ5 desaturation), whereas curcumin and nicardipin decreased Δ5 desaturation, with a limited effect on cholesterol synthesis.