An anti-PDGFRβ aptamer for selective delivery of small therapeutic peptide to cardiac cells

Abstract

Small therapeutic peptides represent a promising field for the treatment of pathologies such as cardiac diseases. However, the lack of proper target-selective carriers hampers their translation towards a potential clinical application. Aptamers are cell-specific carriers that bind with high affinity to their specific target. However, some limitations on their conjugation to small peptides and the functionality of the resulting aptamer-peptide chimera exist. Here, we generated a novel aptamer-peptide chimera through conjugation of the PDGFRβ-targeting Gint4.T aptamer to MP, a small mimetic peptide that via targeting of the Ca v β2 subunit of the L-type calcium channel (LTCC) can recover myocardial function in pathological heart conditions associated with defective LTCC function. The conjugation reaction was performed by click chemistry in the presence of N,N,N',N',N"-pentamethyldiethylenetriamine as a Cu (I) stabilizing agent in a DMSO-free aqueous buffer. When administered to cardiac cells, the Gint4.T-MP aptamer-peptide chimera was successfully internalized in cells, allowing the functional targeting of MP to LTCC. This approach represents the first example of the use of an internalizing aptamer for selective delivery of a small therapeutic peptide to cardiac cells.

The Discovery of RNA Aptamers that Selectively Bind Glioblastoma Stem Cells

“…Recently, we reported the use of GL21.T and Gint4.T aptamers as carriers for miR-137 and anti-miR-10b to target GSCs. Both bind Axl and PDGFRβ,21, 25, 26 respectively, two tyrosine kinase receptors commonly expressed on GBM cells. These aptamers bind to targets shared between stem and differentiated cells.…”

Modified nucleic acids: replication, evolution, and next-generation therapeutics

“…In another recent report, Sullenger and colleagues modified RNA aptamers against prostate cancer cells with 2′F pyrimidines. Upon conjugation with small molecule drugs or therapeutic peptides, these aptamers displayed significant specificity and toxicity against cancerous but not normal cells [ 196 , 197 ]. We direct the reader to a recent review for a more detailed panorama of modified aptamer chemistry and related technologies [ 198 ].…”

Aptamer Chimeras for Therapeutic Delivery: The Challenging Perspectives

“…Recently Romanelli et al [ 43 ] developed a peptide (R7W-MP) that, by targeting Cavβ2, demonstrated to be able to correct the L-type calcium channel (LTCC) density at the plasma membrane, often hampered in various cardiovascular pathological conditions. The R7W-MP peptide is a fusion molecule composed by a R7W CPP fused to a mimetic peptide (MP), able to target the Tail Interacting Domain (TID) in the Cavβ2, inhibiting its interaction with the C-terminal coiled-coil tail (C-tail) in the site where Cavβ2 is phosphorylated by Akt, and thus, preventing Cavβ2 structural rearrangements responsible for increased LTCC density at the plasma membrane.…”

“…The R7W-MP peptide revealed to be able to reestablish normal calcium balance and recover myocardial contractility in mouse models of diabetic cardiomyopathy [ 44 ]. In order to overcome limitations showed by the R7W-MP peptide, essentially in reference to the lack of selectivity of the R7W moiety, the same group developed an aptamer-based approach for the selective delivery of MP mimetic to cardiac cells [ 43 ]. The authors described an innovative approach for direct conjugation of the MP to a 2′-fluoro pyrimidines modified RNA aptamer, named Gint4.T, specifically targeting the PDGFRβ that is abundantly expressed in cardiomyocytes [ 45 ].…”

“… Schematic representation of aptamer-peptide conjugates. ( A ) Direct conjugation through click chemistry of the Gint4.t anti- PDGFRβ aptamer to the active mimetic peptide (MP) described by Romanelli et al [ 43 ]. ( B ) Covalent conjugation of the AS1411 anti-nucleolin aptamer to the cancer cytotoxic melittin peptide described by Rajabnejad et al [ 46 ].…”