<p>Pathogenic bacteria are evolving to drug resistant
strains at alarming rates. The threat posed by drug resistant bacterial
infections emphasize the need to establish new antimicrobial agents. Of
immediate concern regarding the dangers of antibiotic resistance is the
existence of intracellular bacteria, which find refuge from bactericidal devices
by hiding within mammalian cells. Unfortunately, many therapeutics, such as
vancomycin, do not possess membrane penetrating abilities to achieve efficacious
eradication of bacteria at the subcellular level, allowing infections to
persist. In an effort to target pathogens that thrive within mammalian cells,
features of cell penetrating peptides (CPPs) and antimicrobial peptides (AMPs)
were combined to develop a dual action antimicrobial CPP, cationic amphiphilic
polyproline helices (CAPHs). CAPHs have proven to be an effective antimicrobial
agent to combat an array of both Gram negative and Gram positive bacteria. </p>
<p> </p>
<p>Herein, to improve CAPHs activity, we have
demonstrated how the incorporation of strategic modifications has resulted in
increased cell uptake, alternative subcellular locations for CAPHs, and
advanced antimicrobial potency. By simultaneously extending the helical length
of CAPHs while incorporating different hydrophobic groups in place of the original
isobutyl moiety that compose CAPHs we have created a <b>FL-P17-5R </b>series of peptides with five carbon aliphatic motifs: <b>Fl-P17-5B</b>, <b>Fl-P17-5C</b> and <b>Fl-P17-5L. </b>Through
these modifications the peptides proved to be 2 to 5-fold more efficient in
accumulating in macrophage cells than parent peptide Fl-P14LRR and where able
to clear intracellular pathogenic bacteria, such as <i>Listeria</i>, from infected macrophages by 26 to 54%. </p>
<p> </p>
<p>In addition to making the <b>Fl-P17-5R</b> series of CAPHs to potentiate CAPHs activity, modifications
to the cationic moiety of CAPHs were explored. By incorporating a new cationic
monomer into the CAPHs sequence, a guanylated amino proline (GAP) residue, we produced
<b>Fl-P14GAP</b>, a CAPHs peptide with an
organized cationic charge display. This modification resulted in a 5-fold
increase in cell uptake and a 2 to 16-fold decrease in minimum inhibitory
concentration (MIC) values against strains of enteric and ESKAPE pathogens in
comparison to Fl-P14LRR. <b>Fl-P14GAP</b>
also executed superior clearance of intracellular pathogenic bacteria that
resulted in the complete eradication of a drug resistant strain of <i>A. baumannii</i> from infected macrophage
cells. Overall, our efforts with the <b>Fl-P17-5R</b>
series of CAPHs and <b>Fl-P14GAP</b> have
strengthened the therapeutic potential of CAPHs in the hopes of addressing the
need for novel antibiotics with the propensity to eradicate intracellular
pathogens.</p>
| Identifer | oai:union.ndltd.org:purdue.edu/oai:figshare.com:article/9696266 |
| Date | 31 January 2022 |
| Creators | Reena Blade (7289858) |
| Source Sets | Purdue University |
| Detected Language | English |
| Type | Text, Thesis |
| Rights | CC BY 4.0 |
| Relation | https://figshare.com/articles/thesis/STRATEGIC_MODIFICATIONS_TO_OPTIMIZE_A_CELL_PENETRATING_ANTIMICROBIAL_PEPTIDE/9696266 |
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