ABSTRACT
Amphotericin B is the most potent antimycotic known to date. However due to its large collateral toxicity, its use, although long standing, had been limited. Many attempts have been made to produce derivatives with reduced collateral damage. The molecular mechanism of polyene has also been closely studied for this purpose and understanding it would contribute to the development of safe derivatives. Our study examined polyene action, including chemical synthesis, electrophysiology, pharmacology, toxicology and molecular dynamics. The results were used to support a novel Amphotericin B derivative with increased selectivity: L-histidine methyl ester of Amphotericin B. We found that this derivative has the same form of action as Amphotericin B, i.e. pore formation in the cell membrane. Its reduced dimerization in solution, when compared to Amphotericin B, is at least partially responsible for its increased selectivity. Here we also present the results of preclinical tests, which show that the derivative is just as potent as Amphotericin B and has increased safety.
ABSTRACT
Cell penetrating peptides (CPP) and cationic antibacterial peptides (CAP) have similar physicochemical properties and yet it is not understood how such similar peptides display different activities. To address this question, we used Iztli peptide 1 (IP-1) because it has both CPP and CAP activities. Combining experimental and computational modeling of the internalization of IP-1, we show it is not internalized by receptor-mediated endocytosis, yet it permeates into many different cell types, including fungi and human cells. We also show that IP-1 makes pores in the presence of high electrical potential at the membrane, such as those found in bacteria and mitochondria. These results provide the basis to understand the functional redundancy of CPPs and CAPs.
