Western blotting was performed as described in a previous study (20 (link)). Antibodies targeting the following proteins were used: IκBα (CST4812, Cell Signaling Technology, Danvers, MA, USA), p65 (CST6956S, Cell Signaling Technology), CD9 (NBP2-22187, Novus Biologicals, Centennial, CO, USA), CD63 (EXOAB-CD63A-1, SBI, Tokyo, Japan), TSG101 (ab228013, Abcam, Cambridge, UK), GM130 (ab52649, Abcam), glyceraldehyde-3-phosphate dehydrogenase (GAPDH; sc-47724, Santa Cruz Biotechnology, Santa Cruz, CA, USA), histone H3 (ab1791, Abcam), mCherry (ab125096, Abcam), and GFP (CST2555, Cell Signaling Technology).