Stimuli-Responsive Codelivery of Oligonucleotides and Drugs by Self-Assembled Peptide Nanoparticles

Abstract

Ever more emerging combined treatments exploiting synergistic effects of drug combinations demand smart, responsive codelivery carriers to reveal their full potential. In this study, a multifunctional stimuli-responsive amphiphilic peptide was designed and synthesized to self-assemble into nanoparticles capable of co-bearing and -releasing hydrophobic drugs and antisense oligonucleotides for combined therapies. The rational design was based on a hydrophobic l-tryptophan-d-leucine repeating unit derived from a truncated sequence of gramicidin A (gT), to entrap hydrophobic cargo, which is combined with a hydrophilic moiety of histidines to provide electrostatic affinity to nucleotides. Stimuli-responsiveness was implemented by linking the hydrophobic and hydrophilic sequence through an artificial amino acid bearing a disulfide functional group (H3SSgT). Stimuli-responsive peptides self-assembled in spherical nanoparticles in sizes (100-200 nm) generally considered as preferable for drug delivery applications. Responsive peptide nanoparticles revealed notable nucleotide condensing abilities while maintaining the ability to load hydrophobic cargo. The disulfide cleavage site introduced in the peptide sequence induced responsiveness to physiological concentrations of reducing agent, serving to release the incorporated molecules. Furthermore, the peptide nanoparticles, singly loaded or coloaded with boron-dipyrromethene (BODIPY) and/or antisense oligonucleotides, were efficiently taken up by cells. Such amphiphilic peptides that led to noncytotoxic, reduction-responsive nanoparticles capable of codelivering hydrophobic and nucleic acid payloads simultaneously provide potential toward combined treatment strategies to exploit synergistic effects.

Delivery of ROS Generating Anthraquinones Using Reduction‐Responsive Peptide‐Based Nanoparticles

“…The presence of a disulfide bond in the backbone of the amphiphilic peptide H 3 SSgT is intended to trigger the destruction of the NPs in reductive environments and induce the release of the anthraquinones. The release profile of the hydrophobic model payload Bodipy upon incubation in 10 m m dithiothreitol (DTT) was previously reported and showed a rapid release of the compound, reaching 50% after 30 min . In the present case of anthraquinone entrapping NPs, the release profile could not be determined since the studied compounds lack fluorescent properties.…”

“…As the peptide NPs are MCMs, they possess multiple hydrophobic inner cores and thus preferentially entrap hydrophobic compounds. [ ][ ] Therefore, the structural differences between these anthraquinones can affect their loading efficiency within the hydrophobic cores of the peptide NPs. To prepare the loaded NPs, the anthraquinone was added to a peptide solution, diluted to a final concentration of 6 – 12 μ m in 50% ethanol and dialyzed against water.…”

“…More complex self‐assembly structures, namely multi‐compartment‐micelles (MCMs) can host both hydrophilic and hydrophobic drugs, making them especially versatile candidates for drug delivery. We have recently reported the redox‐responsive amphiphilic peptide H 3 SSgT (of the sequence H 2 N ‐H 3 ‐X‐[W‐ D L] 3 ‐W‐ NH 2 , where X = –NH‐(CH 2 ) 2 ‐S‐S‐(CH 2 ) 2 ‐NH‐CO‐(CH 2 ) 2 ‐CO– and D L = d ‐Leucine; Figure ), that forms such MCMs . They were shown to efficiently entrap the model compound boron‐dipyrromethene (Bodipy) and release it in presence of physiological amounts of reducing agent .…”

“…We have recently reported the redox‐responsive amphiphilic peptide H 3 SSgT (of the sequence H 2 N ‐H 3 ‐X‐[W‐ D L] 3 ‐W‐ NH 2 , where X = –NH‐(CH 2 ) 2 ‐S‐S‐(CH 2 ) 2 ‐NH‐CO‐(CH 2 ) 2 ‐CO– and D L = d ‐Leucine; Figure ), that forms such MCMs . They were shown to efficiently entrap the model compound boron‐dipyrromethene (Bodipy) and release it in presence of physiological amounts of reducing agent . The MCMs are about 150 nm in diameter, making them suitable to deploy the EPR effect for tumor tissue uptake.…”

“…[12 -14] They were shown to efficiently entrap the model compound boron-dipyrromethene (Bodipy) and release it in presence of physiological amounts of reducing agent. [13] The MCMs are about 150 nm in diameter, making them suitable to deploy the EPR effect for tumor tissue uptake. In addition to a leaky vasculature leading to the EPR effect, the environment surrounding tumor tissues possess abnormal physicochemical properties such as decreased pH, increased temperature and unusual redox potentials.…”