Protein/oligonucleotide conjugates as a cell specific PNA carrier

Area of Science:

• Bioconjugation Chemistry
• Molecular Delivery Systems
• Hepatocyte Targeting

Background:

• Peptide nucleic acids (PNAs) offer therapeutic potential but require efficient delivery vectors.
• Cell-specific delivery is crucial for targeting therapies to particular cell types, like hepatocytes.
• Protein-oligonucleotide conjugates can be engineered for targeted delivery applications.

Purpose of the Study:

• To develop a protein-oligonucleotide conjugate as a cell-specific delivery vector for PNAs.
• To utilize asialofetuin (AF) as a hepatocyte-specific ligand for targeted delivery.
• To investigate the mechanism of PNA uptake into hepatocytes mediated by the conjugate.

Main Methods:

• Conjugation of succinimidyl-transe-4(N-maleimidylmethyl)-cyclohexane-1-carboxylate (SMCC) modified AF with 5'-thiolated oligodeoxynucleotide (HS-ODN).
• Complex formation of the AF-ODN conjugate with PNAs.
• Assessment of PNA/DNA conjugate stability against nucleases.
• Evaluation of PNA release upon target nucleotide binding.
• Measurement of PNA uptake into hepatocytes using the conjugate.

Main Results:

• A stable PNA/DNA conjugate was successfully synthesized using AF and ODNs.
• The conjugate demonstrated nuclease resistance in serum.
• Efficient PNA release was observed upon binding to target nucleotides.
• Hepatocyte uptake of PNAs was significantly enhanced by the AF-ODN conjugate.
• Free AF blocked uptake, confirming asialoglycoprotein receptor (ASGP-R) mediated endocytosis.

Conclusions:

• Protein-oligonucleotide conjugates serve as effective cell-specific delivery vectors for PNAs.
• The AF-ODN conjugate facilitates targeted PNA delivery to hepatocytes via ASGP-R.
• This delivery strategy shows promise for PNA-based therapeutics targeting liver cells.