Abstract
Current treatments against bacterial infections have severe limitations, mainly due to the emergence of resistance to conventional antibiotics. In the specific case of Pseudomonas aeruginosa strains, they have shown a number of resistance mechanisms to counter most antibiotics. Human secretory RNases from the RNase A superfamily are proteins involved in a wide variety of biological functions, including antimicrobial activity. The objective of this work was to explore the intracellular antimicrobial action of an RNase 3/1 hybrid protein that combines RNase 1 high catalytic and RNase 3 bactericidal activities. To achieve this, we immobilized the RNase 3/1 hybrid on Polyetheramine (PEA)-modified magnetite nanoparticles (MNPs). The obtained nanobioconjugates were tested in macrophage-derived THP-1 cells infected with Pseudomonas aeruginosa PAO1. The obtained results show high antimicrobial activity of the functionalized hybrid protein (MNP-RNase 3/1) against the intracellular growth of P. aeruginosa of the functionalized hybrid protein. Moreover, the immobilization of RNase 3/1 enhances its antimicrobial and cell-penetrating activities without generating any significant cell damage. Considering the observed antibacterial activity, the immobilization of the RNase A superfamily and derived proteins represents an innovative approach for the development of new strategies using nanoparticles to deliver antimicrobials that counteract P. aeruginosa intracellular infection.
Highlights
The rapid emergence of resistant bacteria is occurring worldwide, endangering the efficacy of antibiotics and turning into a public health threat that can compromise millions of lives [1]
We designed an RNase 3/1 hybrid that combines the unique features of RNase 3 and the high catalytic activity and ribonuclease inhibitor affinity of RNase 1 and tested the construct in an in vitro experimental evolution test with Acinetobacter baumannii, where it demonstrated its ability to delay the acquisition of colistin resistance [15]
After PEA coating, HD was measured at 460 nm with a %polydispersity index (PI) of 23 and After conjugation of RNase 3/1, the hydrodynamic diameter increased to 290 nm with a PI of 22%
Summary
The rapid emergence of resistant bacteria is occurring worldwide, endangering the efficacy of antibiotics and turning into a public health threat that can compromise millions of lives [1]. Studies have focused on the search and evaluation of new biomolecules, such as peptides and proteins, with potent antimicrobial activities [3,4] These emerging molecules have been reported to act either alone or in combination to potentiate their action against pathogens. Eight functional RNases’ (named canonical RNases [8]) genes have been identified within a single chromosome This enzyme family includes RNase 1, or pancreatic RNase, expressed in the pancreas as well as in other organs and tissues [9]. RNase 3 stands out for its high bactericidal action and the efficacy of an N-terminus-derived peptide on Gram-negative bacteria biofilms This ability to remove biofilms of Gram-negative species can be explained by its specific cell agglutination and lipopolysaccharide-binding properties [12,13,14,15]. Antimicrobial RNases have been reported to be effective against biofilm-forming pathogens, such as Mycobacterium tuberculosis, A. baumannii, or Pseudomonas aeruginosa [12,13]
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