Antisense peptide nucleic acid-functionalized cationic nanocomplex for in vivo mRNA detection

Area of Science:

• Biomedical Engineering
• Molecular Imaging
• Nanomedicine

Background:

• Acute lung injury (ALI) is a critical condition characterized by inflammation and impaired gas exchange, often linked to inducible nitric oxide synthase (iNOS) overproduction.
• Targeting iNOS mRNA with antisense nucleic acids offers a potential diagnostic and therapeutic strategy for ALI.
• Peptide nucleic acids (PNAs) are promising for antisense applications but face challenges with cell membrane permeability.

Purpose of the Study:

• To develop and evaluate a novel radiolabeled nanocomplex for imaging iNOS mRNA expression.
• To assess the efficacy of the nanocomplex for in vitro and in vivo detection of iNOS in the context of ALI.

Main Methods:

• Preparation of a nanocomplex via electrostatic complexation of a radiolabeled antisense PNA-YR9 · oligodeoxynucleotide (ODN) hybrid with cationic shell-cross-linked knedel-like nanoparticles (cSCK).
• Assessment of nanocomplex binding affinity and cellular uptake in RAW264.7 cells.
• Evaluation of in vitro and in vivo imaging capabilities using (123)I-labeled nanocomplexes in iNOS-induced cellular and mouse models.

Main Results:

• The PNA-YR9 · ODN hybrid successfully complexed with cSCK nanoparticles, forming stable nanocomplexes.
• The nanocomplexes demonstrated efficient cellular uptake in RAW264.7 cells, unlike the PNA-ODN hybrid alone.
• Radiolabeled nanocomplexes showed specific and enhanced retention of radioactivity in iNOS-induced cells and mouse lungs, both in vitro and in vivo, compared to mismatched controls.

Conclusions:

• The developed radiolabeled PNA-ODN/cSCK nanocomplexes serve as a sensitive and specific imaging probe for iNOS mRNA.
• This theranostic approach holds significant potential for the early diagnosis of acute lung injury.