1. Functionalization of mesoporous silica nanoparticles with a cell-penetrating peptide to target mammalian sperm in vitro
Natalia Barkalina, Celine Jones, Helen Townley, Kevin Coward Nanomedicine (Lond). 2015 May;10(10):1539-53. doi: 10.2217/nnm.14.235.
Aim: This study aimed to investigate the effects of actively targeting mesoporous silica nanoparticles (MSNPs) toward mammalian sperm with a cell-penetrating peptide (C105Y), with subsequent analysis of binding rates and nano-safety profiles. Materials & methods: Boar sperm were exposed in vitro to C105Y-functionalized MSNPs or free C105Y, in a series of increasing doses for up to 2 h, followed by the evaluation of sperm motility, kinematic parameters, acrosome morphology, MSNP-sperm binding and cell fluorescence levels. Results: C105Y-functionalized MSNPs preserved their biocompatibility with sperm, and exhibited an approximately fourfold increase in affinity toward gametes, compared with unmodified MSNPs, during the early stages of incubation. Conclusion: Our findings support the application of MSNPs and active targeting to sperm as valuable tools for reproductive biology.
2. Liposome Deformation Induced by Membrane-Binding Peptides
Kayano Izumi, Chihiro Saito, Ryuji Kawano Micromachines (Basel). 2023 Feb 2;14(2):373. doi: 10.3390/mi14020373.
This paper presents an investigation of liposome deformation and shape distortion using four membrane-binding peptides: TAT and C105Y as cell-penetrating peptides (CPPs), and melittin and ovispirin as antimicrobial peptides (AMPs). Liposome deformation was monitored utilizing fluorescent microscopy, while the binding of peptides to the DOPC membrane was estimated through capacitance measurements. The degree of liposome deformation and shape distortion was found to be higher for the CPPs compared to the AMPs. Additionally, it was observed that C105Y did not induce liposome rupture, unlike the other three peptides. We propose that these variations in liposome distortion may be attributed to differences in secondary structure, specifically the presence of an α-helix or random coil. Our studies offer insight into the use of peptides to elicit control of liposome architecture and may offer a promising approach for regulating the bodies of liposomal molecular robots.
3. Mechanism of uptake of C105Y, a novel cell-penetrating peptide
Melanie Rhee, Pamela Davis J Biol Chem. 2006 Jan 13;281(2):1233-40. doi: 10.1074/jbc.M509813200. Epub 2005 Nov 4.
C105Y, a synthetic peptide (CSIPPEVKFNKPFVYLI) based on the amino acid sequence corresponding to residues 359-374 of alpha1-antitrypsin, enhances gene expression from DNA nanoparticles. To investigate how this enhancement occurs, C105Y was fluorescently labeled to study its uptake and intracellular trafficking. When human hepatoma cells (HuH7) were incubated with fluorescently labeled C105Y for as little as 3 min, C105Y displayed nuclear and cytoplasmic staining with enrichment of fluorescent signal in the nucleus and nucleolus. Uptake and nucleolar localization were observed with the short sequence PFVYLI, but not with SIPPEVKFNK, and the D-isomer was readily taken up into cells but not into the nucleus. We found that the C105Y peptide is routed to the nucleolus very rapidly in an energy-dependent fashion, whereas membrane translocation and nuclear localization are energy-independent. When we tested the involvement of known endocytosis pathways in uptake and trafficking of this peptide, we demonstrated that C105Y peptide is internalized by a clathrin- and caveolin-independent pathway, although lipid raft-mediated endocytosis may play a role in peptide intracellular trafficking. Efficient energy-independent cell entry with rapid nuclear localization probably accounts for enhancement of gene expression from inclusion of C105Y into DNA nanoparticles.
