Surface morphology live-cell imaging reveals how macropinocytosis inhibitors affect membrane dynamics. (10th February 2023)

• Record Type: Journal Article
• Authors: Ida, Hiroki; Taira, Noriko; Azuma, Koichi; Kumatani, Akichika; Akishiba, Misao; Futaki, Shiroh; Takahashi, Yasufumi; Shiku, Hitoshi
• Is Part Of: Electrochimica acta. Volume 441(2023)
• Publication Date: 2023-02-10
• Subjects: SICM scanningion conductance microscopy -- Macropinocytosis inhibitor -- Live cell imaging; SICM Scanning Ion Conductance Microscopy -- NaN3 sodium azide -- EIPA 5-(N-ethyl-N-isopropyl)-Amiloride -- 2D FFT two-dimensional Fast Fourier Transform; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2022.141783
• Languages: English
• ISSNs: 0013-4686

Abstract

Abstract: Macropinocytosis is a unique endocytic pathway that involves dynamic membrane ruffling and is important in various cellular functions beyond nutrient uptake. Due to its impact, macropinocytosis has been the subject of various studies and macropinocytosis inhibitors have been widely used. However, inhibitors exhibit offtarget effects and could be less specific for macropinocytosis, thereby affecting various cellular mechanisms with effects on nanoscale membrane dynamics that remain elusive. In this study, we revealed how five different inhibitors affect membrane dynamics before and after treatment using scanning ion conductance microscopic imaging on living cells. Our results indicated that cytochalasins and sodium azide exhibited similar slowing effects on horizontal ruffle movements, even though their inhibitory mechanisms are different. In contrast, ruffle deformation and elongation were less strongly inhibited compared to the movements along cell membrane direction. These results suggested the involvement of mechanisms beyond actin polymerization. The ruffles disappeared and the cell surface smoothened upon the 5-(N-ethyl-N-isopropyl)-Amiloride treatment. In the presence of wortmannin, we observed active ruffles but no cup-like structures. These findings and scanning ion conductance microscopy live-cell imaging would potentially contribute to a better understanding of inhibitor effects.