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

Alessandra Romanelli,Concetta Avitabile,Silvia Catuogno,Alessandra Affinito,Jessica Modica,Geroloma Condorelli,Margherita Iaboni,Paola Ceriotti,Daniele Catalucci,Fabio Martelli

doi:10.1371/journal.pone.0193392

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 Cavβ2 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.

Highlights

Therapeutic peptides for clinical applications have recently obtained increasing interest, reaching over 60 FDA-approved products on the market and more than 150 mimetic peptides in clinical trials [1, 2]
To provide guidance for targeting of mimetic peptide (MP) to the heart, we conjugated it to the Gint4.T aptamer, which we previously showed promotes the functional internalization of miRNAs and antimiRs in a PDGFRβ-dependent manner [21, 22]
This was achieved through Cu (I)-mediated click chemistry, an approach poorly explored mainly due to difficulties associated with RNA degradation caused by Cu (I) disproportionation and subsequent redox reactions

Summary

Introduction

Therapeutic peptides for clinical applications have recently obtained increasing interest, reaching over 60 FDA-approved products on the market and more than 150 mimetic peptides in clinical trials [1, 2]. Despite the encouraging results obtained for the therapeutic treatment of LTCC-related cardiac conditions, such as diabetic cardiomyopathy [6, 7], the use of R7W-MP faces limitations due to the broad tissue targeting of the R7W moiety, which is not cell specific and may thereby lead to potential side effects at other locations where the Cavβ target is expressed. This limitation highlights the critical need for the identification of novel and more cell-specific targeting carriers. The development of aptamer-peptide conjugates has a broader applicability for the selective delivery and intracellular penetration of therapeutic peptides in several diseases, including cancer [13]

Material and methods

Results and discussion

Conclusions