Enhancement of the activity of the antimicrobial p... - LL-37 Study

Key Findings

RNase alone has no antimicrobial activity

RNase boosts LL‑37’s killing power at very high bacterial concentrations

tRNA blocks some peptide activity but RNase’s boost can overcome that

Practical Outcomes

For biohackers, the finding hints that combining RNase with LL‑37 might improve antibacterial effects in situations with heavy bacterial loads, such as topical infections, but there’s no proven human protocol yet and more research is needed.

Summary

The study shows that mixing the enzyme RNase with the antimicrobial peptide LL‑37 can make LL‑37 work better against lots of bacteria, while RNase alone doesn’t kill bacteria. This effect was seen in lab tests with high bacterial counts, not in people.

Abstract

Background: HNP1, LL-37, and HBD1 are antimicrobial against Escherichia coli ATCC 25922 at the standard inoculum but less active at higher inocula.   Methods: The virtual colony count (VCC) microbiological assay was adapted for high inocula and the addition of yeast tRNA and bovine pancreatic ribonuclease A (RNase).  96-well plates were read for 12 hours in a Tecan Infinite M1000 plate reader and photographed under 10x magnification.    Results: Adding tRNA 1:1 wt/wt to HNP1 at the standard inoculum almost completely abrogated activity.  Adding RNase 1:1 to HNP1 at the standard inoculum of 5x10 5 CFU/mL did not enhance activity.  Increasing the inoculum to 6.25x10 7 CFU/mL almost abrogated HNP1 activity.  However, adding RNase 25:1 to HNP1 enhanced activity at the highest tested concentration of HNP1.  Adding both tRNA and RNase resulted in enhanced activity, indicating that the enhancement effect of RNase overwhelms the inhibiting effect of tRNA when both are present.  HBD1 activity at the standard inoculum was almost completely abrogated by the addition of tRNA, but LL-37 activity was only slightly inhibited by tRNA.  At the high inoculum, LL-37 activity was enhanced by RNase.  HBD1 activity was not enhanced by RNase.  RNase was not antimicrobial in the absence of antimicrobial peptides.  Cell clumps were observed at the high inoculum in the presence of all three antimicrobial peptides and at the standard inoculum in the presence of HNP1+tRNA and HBD1+tRNA.    Conclusions: Antimicrobial peptide-ribonuclease combinations have the potential to be active against high cell concentrations, conditions where the antimicrobial agent alone is relatively ineffective.

Study Information

Provider

pubmed

Year

2023

Date

2023-03-13T00:00:00.000Z

DOI

10.12688/f1000research.123044.3

Citations

References