Inhibition of receptor internalization attenuates the TNFα-induced ROS generation in non-phagocytic cells

Reactive oxygen species (ROS) are important regulatory molecules implicated in the signaling cascade triggered by tumor necrosis factor (TNF)α, although the events through which TNFα induces ROS generation are not well characterized. Here, we report that TNFα-induced ROS production was blocked by pretreatment with internalization inhibitor monodansyl cadaverine (MDC). Similarly, a transient expression of a GTP-binding and hydrolysis-defective dynamin mutant (dynaminK44A) that had been shown to be defective in internalization significantly attenuated the TNFα-induced intracellular ROS production. Importantly, the inhibition of receptor internalization suppressed TNFα signaling to mitogen-activated protein kinases (MAPKs) stimulation. Together, our results suggest that receptor internalization is somehow necessary for the TNFα-induced ROS generation and subsequent intracellular downstream signaling in non-phagocytes.