Figure 2. Pharmacological and genetic... | Rockefeller University Press

Figure 2.

$Figure 2. Pharmacological and genetic inhibition of Dyn2 function also reduces starvation-induced LD breakdown. HuH-7 (A) and Hep3B (B) hepatocytes were loaded with 150 µM oleate overnight and starved for 48 h in medium containing 0.1% FBS in the presence of Dyn2 inhibitors or DMSO as indicated. Representative images of inhibitor-treated and control cells (stained with Oil Red O) are shown in A and B together with the quantitation of the average LD area per cell from three independent experiments. Pharmacological inhibitors used were: Dynasore (inhibits Dyn2 GTPase activity), MiTMAB (targets PH domain and interferes with membrane binding), Dynole 34-2 (allosteric GTPase inhibitor), and Dynole 31-2 (negative control for Dynole 34-2). Bars, 20 µM. (C) Representative images from control and Dyn2 knockout MEFs after an overnight lipid loading with 400 µM oleate for 17 h. Knockout of Dyn2 was induced by treatment with 2 µM 4-hydroxy-tamoxifen for 7 d and was confirmed by immunostaining of endogenous Dyn2 (top row) and by immunoblot (D). Bars, 20 µM. (E and F) Average LD number (E) and area (F) per cell from five independent experiments. All data are represented as mean ± SE. *, P ≤ 0.05; **, P ≤ 0.01. (G) Whole-cell lysates and LD fractions isolated from HuH-7 hepatocytes under resting or starved (2 h HBSS starvation) conditions. (H) Primary hepatocyte expressing Dyn2-GFP, showing an absence of colocalization with the LD surface (stained with Oil Red O). Bar, 20 µM. Inset shows magnification of boxed region (bar, 2 µM).$

Pharmacological and genetic inhibition of Dyn2 function also reduces starvation-induced LD breakdown. HuH-7 (A) and Hep3B (B) hepatocytes were loaded with 150 µM oleate overnight and starved for 48 h in medium containing 0.1% FBS in the presence of Dyn2 inhibitors or DMSO as indicated. Representative images of inhibitor-treated and control cells (stained with Oil Red O) are shown in A and B together with the quantitation of the average LD area per cell from three independent experiments. Pharmacological inhibitors used were: Dynasore (inhibits Dyn2 GTPase activity), MiTMAB (targets PH domain and interferes with membrane binding), Dynole 34-2 (allosteric GTPase inhibitor), and Dynole 31-2 (negative control for Dynole 34-2). Bars, 20 µM. (C) Representative images from control and Dyn2 knockout MEFs after an overnight lipid loading with 400 µM oleate for 17 h. Knockout of Dyn2 was induced by treatment with 2 µM 4-hydroxy-tamoxifen for 7 d and was confirmed by immunostaining of endogenous Dyn2 (top row) and by immunoblot (D). Bars, 20 µM. (E and F) Average LD number (E) and area (F) per cell from five independent experiments. All data are represented as mean ± SE. *, P ≤ 0.05; **, P ≤ 0.01. (G) Whole-cell lysates and LD fractions isolated from HuH-7 hepatocytes under resting or starved (2 h HBSS starvation) conditions. (H) Primary hepatocyte expressing Dyn2-GFP, showing an absence of colocalization with the LD surface (stained with Oil Red O). Bar, 20 µM. Inset shows magnification of boxed region (bar, 2 µM).