Laboratório de Bioquímica Celular, Universidade Federal de São João del Rei, Campus Centro-Oeste Dona Lindu, Av Sebastião Gonçalves Coelho, 400, Divinópolis, MG, Zip Code: 35501-296, Brazil.
Laboratório de Bioquímica de Membranas e ATPases, Universidade Federal de São João del Rei, Campus Centro-Oeste Dona Lindu, Divinópolis, MG, Brazil.
J Membr Biol. 2021 Dec;254(5-6):499-512. doi: 10.1007/s00232-021-00203-z. Epub 2021 Oct 29.
We have previously shown that 21-benzylidene digoxin (21-BD) increases the total cholesterol and phospholipid content on the membrane of HeLa cells. Lipid modulation caused by cardiotonic steroids (CTS) is still unexplored. Therefore, the aim of the present study was to evaluate the cholesterol and phospholipid modulation of the cell membrane caused by ouabain and 21-BD and the possible involvement of the caveolae on this modulation. For this, one cell line containing caveolae (HeLa) and other not containing (Caco-2) were used. The modulation of the lipid profile was evaluated by total cholesterol and phospholipids measurements, and identification of membrane phospholipids by HPTLC. The cholesterol distribution was evaluated by filipin staining. The caveolin-1 expression was evaluated by Western Blotting. Ouabain had no effect on the total membrane lipid content in both cell lines. However, 21-BD increased total membrane phospholipid content and had no effect on the membrane cholesterol content in Caco-2 cells. CTS were not able to alter the specific phospholipids content. In the filipin experiments, 21-BD provoked a remarkable redistribution of cholesterol to the perinuclear region of HeLa cells. In Caco-2 cells, it was observed only a slight increase in cholesterol, especially as intracellular vesicles. The caveolin-1 expression was not altered by any of the compounds. Our data mainly show different effects of two cardiotonic steroids. Ouabain had no effect on the lipid profile of cells, whereas 21-BD causes important changes in cholesterol and phospholipid content. Therefore, the modulation of cholesterol content in the plasma membrane of HeLa cells is not correlated with the expression of caveolin-1.
我们之前已经表明，21-苄基洋地黄毒苷（21-BD）可增加 HeLa 细胞膜上的总胆固醇和磷脂含量。强心甾类化合物（CTS）引起的脂质调节仍未得到探索。因此，本研究旨在评估哇巴因和 21-BD 对细胞膜胆固醇和磷脂的调节作用，以及质膜小窝是否参与这种调节作用。为此，我们使用了一种含有质膜小窝（HeLa）的细胞系和另一种不含有质膜小窝（Caco-2）的细胞系。通过总胆固醇和磷脂的测量以及 HPTLC 鉴定来评估脂质谱的调节。用 filipin 染色评估胆固醇的分布。通过 Western Blotting 评估 caveolin-1 的表达。哇巴因对两种细胞系的总膜脂质含量均无影响。然而，21-BD 增加了 Caco-2 细胞的总膜磷脂含量，对膜胆固醇含量没有影响。CTS 不能改变特定的磷脂含量。在 filipin 实验中，21-BD 导致胆固醇在 HeLa 细胞的核周区发生明显重分布。在 Caco-2 细胞中，仅观察到胆固醇轻度增加，尤其是作为细胞内囊泡。任何一种化合物都没有改变 caveolin-1 的表达。我们的数据主要显示了两种强心甾类化合物的不同作用。哇巴因对细胞的脂质谱没有影响，而 21-BD 导致胆固醇和磷脂含量发生重要变化。因此，HeLa 细胞膜胆固醇含量的调节与 caveolin-1 的表达无关。
