Helix stabilization of amphipathic peptides by hydrocarbon stapling increases cholesterol efflux by the ABCA1 transporter

Abstract

Apolipoprotein mimetic peptides are short amphipathic peptides that efflux cholesterol from cells by the ABCA1 transporter and are being investigated as therapeutic agents for cardiovascular disease. We examined the role of helix stabilization of these peptides in cholesterol efflux. A 23-amino acid long peptide (Ac-VLDSFKVSFLSALEEYTKKLNTQ-NH2) based on the last helix of apoA-I (A10) was synthesized, as well as two variants, S1A10 and S2A10, in which the third and fourth and third and fifth turn of each peptide, respectively, were covalently joined by hydrocarbon staples. By CD spectroscopy, the stapled variants at 24°C were more helical in aqueous buffer than A10 (A10 17%, S1A10 62%, S2A10 97%). S1A10 and S2A10 unlike A10 were resistant to proteolysis by pepsin and chymotrypsin. S1A10 and S2A10 showed more than a 10-fold increase in cholesterol efflux by the ABCA1 transporter compared to A10. In summary, hydrocarbon stapling of amphipathic peptides increases their helicity, makes them resistant to proteolysis and enhances their ability to promote cholesterol efflux by the ABCA1 transporter, indicating that this peptide modification may be useful in the development of apolipoprotein mimetic peptides.

Amphipathic polyproline peptides stimulate cholesterol efflux by the ABCA1 transporter

“…Amphipathic peptides that efflux cholesterol are typically at least 18 residues or longer, because much shorter peptides cannot form stable helices. Adding salt bridges [2] or hydrocarbon staples [23] to stabilize helix formation has been shown to increase the ability of these peptides to efflux cholesterol by ABCA1.…”

Stapled peptide design: principles and roles of computation

“…Various studies have reported the therapeutic potential of hydrocarbonstapled peptides in the treatment of cancer, specifically by inhibiting the NOTCH transcription factor complex [25], reactivating the p53 tumour suppressor pathway [39][40][41][42], and promoting B cell lymphoma 2 (Bcl-2)-mediated apoptosis [43]. They have also shown potential as therapeutic agents for various other diseases, such as HIV [44,45], diabetes [46], cardiovascular disease [47], and respiratory infection [48]. Two hydrocarbon-stapled peptides developed by Aileron Therapeutics are currently undergoing clinical trials for the treatment of orphan endocrine disorders and malignant tumours [49].…”

Macrocyclic α-Helical Peptide Drug Discovery

“…In addition, the stapled Notch peptide 11 49 (Figure 9.5) is an example of a strongly hydrophilic helical peptide with cell-penetrating properties, which incorporates a single-turn, hydrocarbon-bridged macrocycle. Moreover, the stapled co-activator peptide 12, which binds the estrogen receptor, 50 and stapled apolipoprotein A-1 fragment peptide 13, which binds and increases cholesterol efflux by the ABCA1 transporter, 51 have recently been described ( Figure 9.5). Novel single-turn i,i13 a-helical and i,i13 3 10 -helical (defined as having three amino acid residues/turn and ten atoms comprising the intramolecular H-bonding substructure) peptide stabilization using ringclosing metathesis methodology has also been achieved, as exemplified by stapled peptide models 14 52 and 15, 53 respectively ( Figure 9.5).…”