A Brain-Permeable Aminosterol Regulates Cell Membranes to Mitigate the Toxicity of Diverse Pore-Forming Agents

Abstract

The molecular composition of the plasma membrane plays a key role in mediating the susceptibility of cells to perturbations induced by toxic molecules. The pharmacological regulation of the properties of the cell membrane has therefore the potential to enhance cellular resilience to a wide variety of chemical and biological compounds. In this study, we investigate the ability of claramine, a blood–brain barrier permeable small molecule in the aminosterol class, to neutralize the toxicity of acute biological threat agents, including melittin from honeybee venom and α-hemolysin from Staphylococcus aureus . Our results show that claramine neutralizes the toxicity of these pore-forming agents by preventing their interactions with cell membranes without perturbing their structures in a detectable manner. We thus demonstrate that the exogenous administration of an aminosterol can tune the properties of lipid membranes and protect cells from diverse biotoxins, including not just misfolded protein oligomers as previously shown but also biological protein-based toxins. Our results indicate that the investigation of regulators of the physicochemical properties of cell membranes offers novel opportunities to develop countermeasures against an extensive set of cytotoxic effects associated with cell membrane disruption.

Combinations of Vitamin A and Vitamin E Metabolites Confer Resilience against Amyloid-β Aggregation

“…Authenticated SH-SY5Y cells (ATCC, Virginia, USA) were cultured in DMEM/F-12 with l -glutamine, HEPES, and phenol red (11330032, Thermo Fisher Gibco, Massachusetts, USA) and supplemented with 10% FBS and 1.0% antibiotics (penicillin–streptomycin, Thermo Fisher Gibco, Massachusetts, USA). Cell cultures were maintained in a 5% CO 2 -humidified atmosphere at 37 °C and grown until they reached 80% confluence for a maximum of 20 passages. , The cell line tested negative for mycoplasma contamination.…”

“…Aβ42 oligomers (3 μM, in monomer equivalents) formed with or without vitamins were added to cell culture medium for 1 h at 37 °C under quiescent conditions and then added to the cell culture medium of SH-SY5Y cells seeded in 96-well plates for 24 h. All samples contained a final concentration of 1% DMSO, which was confirmed not to significantly change the viability of the untreated cells or the toxicity of Aβ42 oligomers. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) was purchased from Sigma-Aldrich, Missouri, USA, and the MTT reduction assay was performed as previously described. , Briefly, cells were exposed to solutions of oligomers and vitamins for 24 h at 37 °C. This solution was removed (therein removing any vitamins present in the extracellular medium) and 0.5 mg/mL MTT added for 4 h at 37 °C, after which time the MTT solution was removed and replaced with DMSO for 1 h at room temperature with agitation (150 rpm).…”

“…Cell cultures were maintained in a 5% CO 2humidified atmosphere at 37 °C and grown until they reached 80% confluence for a maximum of 20 passages. 29,35 The cell line tested negative for mycoplasma contamination.…”

“…3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) was purchased from Sigma-Aldrich, Missouri, USA, and the MTT reduction assay was performed as previously described. 29,35 Briefly, cells were exposed to solutions of oligomers and vitamins for 24 h at 37 °C. This solution was removed (therein removing any vitamins present in the extracellular medium) and 0.5 mg/mL MTT added for 4 h at 37 °C, after which time the MTT solution was removed and replaced with DMSO for 1 h at room temperature with agitation (150 rpm).…”

Drug repurposing screens identifies compounds that inhibit α-synuclein oligomers’ membrane disruption and block antibody interactions

“…The membrane blocking phenomenon has previously been observed for several aminosterol compounds such as squalamine and trodusquemine, which in this way are thought to suppress the toxicity of Aβ and αSOs 19,56,57 . Claramine, a blood-brain barrier permeable small molecule from the aminosterol class, has also shown to prevent the toxicity of pore forming agents including melittin from honeybee venom and α-hemolysin from Staphylococcus aureus 58 . Compounds A8 and A10 reduced the amount of calcein release but did not affect binding to DOPG liposomes, suggesting that the compounds could perhaps reduce oligomer membrane permeabilization without preventing binding (e.g.…”