Kontrová K, Zídková J, Bartos B, Skop V, Sajdok J, Kazdová L, Mikulík K, Mlejnek P, Zídek V, Pravenec M
Department of Biochemistry and Microbiology, Institute of Chemical Technology, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
Physiol Res. 2007;56(4):493-496. doi: 10.33549/physiolres.931324.
In the current study, we tested a hypothesis that CD36 fatty acid (FA) transporter might affect insulin sensitivity by indirect effects on FA composition of adipose tissue. We examined the effects of CD36 downregulation by RNA interference in 3T3-L1 adipocytes on FA transport and composition and on sensitivity to insulin action. Transfected 3T3-L1 adipocytes, without detectable CD36 protein, showed reduced neutral lipid levels and significant differences in FA composition when levels of essential FA and their metabolites were lower or could not be detected including gamma linolenic (C18:3 n6), eicosadienic (C20:2 n6), dihomo-gamma linolenic (C20:3 n6), eicosapentaenoic (EPA) (C20:5 n3), docosapentaenoic (DPA) (C22:5 n3), and docosahexaenoic (DHA) (C22:6 n3) FA. Transfected 3T3-L1 adipocytes exhibited a significantly higher n6/n3 FA ratio, reduced 5-desaturase and higher 9-desaturase activities. These lipid profiles were associated with a significantly reduced insulin-stimulated glucose uptake (4.02+/-0.1 vs. 8.42+/-0.26 pmol.10(-3) cells, P=0.001). These findings provide evidence that CD36 regulates FA composition thereby affecting sensitivity to insulin action in 3T3-L1 adipocytes.
在本研究中，我们验证了一个假说，即CD36脂肪酸（FA）转运蛋白可能通过对脂肪组织FA组成的间接影响来影响胰岛素敏感性。我们研究了RNA干扰介导的3T3-L1脂肪细胞中CD36下调对FA转运、组成以及胰岛素作用敏感性的影响。转染后的3T3-L1脂肪细胞中未检测到CD36蛋白，当必需脂肪酸及其代谢产物水平较低或无法检测到时，包括γ-亚麻酸（C18:3 n6）、二十碳二烯酸（C20:2 n6）、二高-γ-亚麻酸（C20:3 n6）、二十碳五烯酸（EPA）（C20:5 n3）、二十二碳五烯酸（DPA）（C22:5 n3）和二十二碳六烯酸（DHA）（C22:6 n3）FA，其中性脂质水平降低，FA组成存在显著差异。转染后的3T3-L1脂肪细胞表现出显著更高的n6/n3 FA比值、降低的5-去饱和酶活性和更高的9-去饱和酶活性。这些脂质谱与胰岛素刺激的葡萄糖摄取显著降低相关（4.02±0.1对8.42±0.26 pmol·10⁻³细胞，P = 0.001）。这些发现提供了证据，表明CD36调节FA组成，从而影响3T3-L1脂肪细胞对胰岛素作用的敏感性。
