Antimicrobial and cell-penetrating properties of penetratin analogs:effect of sequence and secondary structure

AbstractCell-penetrating peptides (CPPs) and antimicrobial peptides (AMPs) show great potential as drug delivery vectors and new antibiotic drug entities, respectively. The current study deals with the properties of a variety of peptide analogs derived from the well-known CPP penetratin as well as octaarginine and different Tat sequences. The effects of peptide length, guanidinium content, and sequence of non-cationic residues were assessed in mammalian and bacterial cells. The arginine (Arg) content in the penetratin analogs was found to influence eukaryotic cell uptake efficiency, antimicrobial activity towards both Gram-positive and Gram-negative bacteria as well as eukaryotic cell viability. All examined analogs retained the ability to cross eukaryotic membranes giving rise to a distribution within the vacuolar apparatus. Interestingly, a series of shuffled analogs of penetratin with the cationic residues in conserved positions, attain the same α-helical conformation as native penetratin in the presence of cholesterol-containing liposomes, while conformational differences were observed in the presence of highly anionic liposomes. While the antibacterial effect of the two groups of peptides was similar, the eukaryotic cellular uptake of the shuffled analogs was noticeably lower than for native penetratin. Moreover, a point substitution of Met to Leu in native penetratin had no influence on eukaryotic cellular uptake and antimicrobial effect, and only a minor effect on cytotoxicity, in contrast to the fact that the same substitution in the shuffled analog gave rise to reduced eukaryotic cellular uptake while increasing the antibacterial effect and cytotoxicity

No QTc Prolongation with Semaglutide: A Thorough QT Study in Healthy Subjects

<p><b> </b></p> <p></p><p><b>Article full text</b></p> <p><br></p> <p>The full text of this article can be found here<b>. </b><a href="https://link.springer.com/article/10.1007/s13300-018-0442-0" rel="noreferrer nofollow" target="_blank">https://link.springer.com/article/10.1007/s13300-018-0442-0</a></p> <p><br></p> <p><b>Provide enhanced content for this article</b></p> <p><br></p> <p>If you are an author of this publication and would like to provide additional enhanced content for your article then please contact <a href="http://www.medengine.com/Redeem/”mailto:[email protected]”"><b>[email protected]</b></a>.</p> <p><br></p> <p>The journal offers a range of additional features designed to increase visibility and readership. All features will be thoroughly peer reviewed to ensure the content is of the highest scientific standard and all features are marked as ‘peer reviewed’ to ensure readers are aware that the content has been reviewed to the same level as the articles they are being presented alongside. Moreover, all sponsorship and disclosure information is included to provide complete transparency and adherence to good publication practices. This ensures that however the content is reached the reader has a full understanding of its origin. No fees are charged for hosting additional open access content.</p> <p><br></p> <p>Other enhanced features include, but are not limited to:</p> <p><br></p> <p>• Slide decks</p> <p>• Videos and animations</p> <p>• Audio abstracts</p> <p>• Audio slides</p><br><p></p

Tailoring Cytotoxicity of Antimicrobial Peptidomimetics with High Activity against Multidrug-Resistant <i>Escherichia coli</i>

Infections with multidrug-resistant pathogens are an increasing concern for public health. Recently, subtypes of peptide–peptoid hybrids were demonstrated to display potent activity against multidrug-resistant Gram-negative bacteria. Here, structural variation of these antibacterial peptidomimetics was investigated as a tool for optimizing cell selectivity. A protocol based on dimeric building blocks allowed for efficient synthesis of an array of peptide–peptoid oligomers representing length variation as well as different backbone designs displaying chiral or achiral peptoid residues. Lack of α-chirality in the side chains of the peptoid residues proved to be correlated to reduced cytotoxicity. Furthermore, optimization of the length of these peptidomimetics with an alternating cationic–hydrophobic design was a powerful tool to enhance the selectivity against Gram-negative pathogens over benign mammalian cells. Thus, lead compounds with a high selectivity toward killing of clinically important multidrug-resistant <i>E. coli</i> were identified