Impact of different cell penetrating peptides on the efficacy of antisense therapeutics for targeting intracellular pathogens

• Published in: Scientific reports Vol. 6; no. 1; p. 20832
• Main Authors: Abushahba, Mostafa F. N., Mohammad, Haroon, Thangamani, Shankar, Hussein, Asmaa A. A., Seleem, Mohamed N.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 10.02.2016; Nature Publishing Group
• Subjects: 631/250/2499; 692/308/153; Amino Acid Sequence; Animals; Anti-Bacterial Agents - pharmacology; Antibacterial activity; Antisense therapy; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Caenorhabditis elegans - drug effects; Caenorhabditis elegans - microbiology; Cell culture; Cell-Penetrating Peptides - chemistry; Cell-Penetrating Peptides - metabolism; Cell-Penetrating Peptides - pharmacology; DNA-directed RNA polymerase; DNA-Directed RNA Polymerases - genetics; DNA-Directed RNA Polymerases - metabolism; Gene silencing; Genes; Humanities and Social Sciences; Intracellular; Listeria; Listeria monocytogenes; Listeria monocytogenes - drug effects; Listeria monocytogenes - genetics; Listeria monocytogenes - metabolism; Listeriolysin O; Medical innovations; Microbial Sensitivity Tests; Mitochondria; multidisciplinary; Oligonucleotides, Antisense - chemistry; Oligonucleotides, Antisense - metabolism; Oligonucleotides, Antisense - pharmacology; Pathogens; Peptide nucleic acids; Peptide Nucleic Acids - chemistry; Peptide Nucleic Acids - metabolism; Peptide Nucleic Acids - pharmacology; Protein biosynthesis; Protein synthesis; RpoA gene; Science; Virulence; Virulence - genetics
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/srep20832

There is a pressing need for novel and innovative therapeutic strategies to address infections caused by intracellular pathogens. Peptide nucleic acids (PNAs) present a novel method to target intracellular pathogens due to their unique mechanism of action and their ability to be conjugated to cell penetrating peptides (CPP) to overcome challenging delivery barriers. In this study, we targeted the RNA polymerase α subunit ( rpo A) using a PNA that was covalently conjugated to five different CPPs. Changing the conjugated CPP resulted in a pronounced improvement in the antibacterial activity observed against Listeria monocytogenes in vitro , in cell culture and in a Caenorhabditis elegans ( C. elegans ) infection model. Additionally, a time-kill assay revealed three conjugated CPPs rapidly kill Listeria within 20 minutes without disrupting the bacterial cell membrane. Moreover, rpo A gene silencing resulted in suppression of its message as well as reduced expression of other critical virulence genes (Listeriolysin O and two phospholipases plc A and plc B) in a concentration-dependent manner. Furthermore, PNA-inhibition of bacterial protein synthesis was selective and did not adversely affect mitochondrial protein synthesis. This study provides a foundation for improving and developing PNAs conjugated to CPPs to better target intracellular pathogens.