To elucidate the involvement of the cell envelope in the stiffness of sickle cells, methyl-β-cyclodextrin (MβCD), a putative cholesterol-depleting reagent which was reportedly able to change the biomechanical properties of the plasma membrane and the membrane association of the membrane skeleton, was subsequently recruited. The following findings are achieved: (a) MβCD can deplete cholesterol in the plasma membrane of erythrocytes at relatively low concentration (≤ 0.8 mM) and destroy the cell envelope (e.g., the formation of large pits) or even degrade entire erythrocytes at a high concentration (≥ 1.6 mM) for both normal and sickle erythrocytes; (b) the surface of normal/sickle erythrocytes treated by MβCD is rougher than that of untreated cells ; (c) the MβCD-treated normal/sickle cell ghosts are rougher and thinner than untreated ghosts (26.4 ± 4.0 nm before MβCD treatment vs. 22.4 ± 4.1 nm after treatment for two layers of sickle ghosts and 21.3 ± 2.8 nm before treatment vs. 17.9 ± 1.9 nm after treatment for two layers of normal ghosts, respectively); (d) the MβCD-treated normal/sickle erythrocytes are softer than untreated cells, and MβCD can induce a more significant decrease in stiffness of sickle cells than that of normal erythrocytes (6.036 ± 2.577 kPa before MβCD treatment vs. 4.456 ± 1.659 kPa after treatment for sickle cells and 2.597 ± 1.221 kPa before treatment vs. 1.847 ± 0.909 kPa after treatment for normal cells, respectively).
Wang, K., Li, Z., Egini, O. et al. Atomic force microscopy reveals involvement of the cell envelope in biomechanical properties of sickle erythrocytes. BMC Biol 21, 31 (2023). https://doi.org/10.1186/s12915-023-01523-3