Targeting regenerative exosomes to myocardial infarction using cardiac homing peptide

Abstract

Rationale: Cardiac stem cell-derived exosomes have been demonstrated to promote cardiac regeneration following myocardial infarction in preclinical studies. Recent studies have used intramyocardial injection in order to concentrate exosomes in the infarct. Though effective in a research setting, this method is not clinically appealing due to its invasive nature. We propose the use of a targeting peptide, cardiac homing peptide (CHP), to target intravenously-infused exosomes to the infarcted heart.Methods: Exosomes were conjugated with CHP through a DOPE-NHS linker. Ex vivo targeting was analyzed by incubating organ sections with the CHP exosomes and analyzing with fluorescence microscopy. In vitro assays were performed on neonatal rat cardiomyocytes and H9C2 cells. For the animal study, we utilized an ischemia/reperfusion rat model. Animals were treated with either saline, scramble peptide exosomes, or CHP exosomes 24 h after surgery. Echocardiography was performed 4 h after surgery and 21 d after surgery. At 21 d, animals were sacrificed, and organs were collected for analysis.Results: By conjugating the exosomes with CHP, we demonstrate increased retention of the exosomes within heart sections ex vivo and in vitro with neonatal rat cardiomyocytes. In vitro studies showed improved viability, reduced apoptosis and increased exosome uptake when using CHP-XOs. Using an animal model of ischemia/reperfusion injury, we measured the heart function, infarct size, cellular proliferation, and angiogenesis, with improved outcomes with the CHP exosomes.Conclusions: Our results demonstrate a novel method for increasing delivery of for treatment of myocardial infarction. By targeting exosomes to the infarcted heart, there was a significant improvement in outcomes with reduced fibrosis and scar size, and increased cellular proliferation and angiogenesis.

Engineered Exosomes With Ischemic Myocardium‐Targeting Peptide for Targeted Therapy in Myocardial Infarction

“…In research by Won et al,44 they presented that a polymeric gene carrier conjugated with IMTP (CSTSMLKAC) was capable of targeting ischemic myocardium, resulting in high localization within the ischemic zone of the LV of an ischemia/reperfusion rat model on systemic administration. Vandergriff et al45 conjugated cardiac stem cell–derived exosomes with IMTP through a dioleoylphosphatidylethanolamine N‐hydroxysuccinimide linker, demonstrating an increasing retention of the IMTP‐exosomes within the ischemia/reperfusion injured heart tissues and a significant improvement in cardiac function.…”

Message in a Bottle: Upgrading Cardiac Repair into Rejuvenation

“…It is important to bear in mind that not all cardiovascular patients may be eligible for acute in situ treatment requiring either percutaneous coronary intervention/angioplasty or collateral cardiac surgery; therefore, there is an increasing need for optimizing EV cardiac-specific homing for future cell-free paracrine therapy. Several studies have been lately reported suggesting alternative strategies to functionalise EVs for more accurate targeting of the damaged heart [220,221]. These include: lentiviral vector-based engineering of secreting cells to upregulate the expression of cardiomyocyte-specific binding peptides fused to the murine transmembrane protein Lamp2b, in order to enrich the targeting epitope on the exosomal surface [222]; overexpression of exosomal CXCR4 to push their bioavailability towards the ischaemic heart [156]; membrane anchoring systems to directly dock tissue-specific antibodies or homing antigens on the EV surface [223,224].…”

Turning regenerative technologies into treatment to repair myocardial injuries

“…Exosomes derived from CPCs engineered to overexpress CXCR4, a receptor of the chemokine stromal cell‐derived factor 1 (SDF‐1), increase myocardium homing and cardioprotective effects in a rat model of ischaemia/reperfusion injury after systemic delivery . The enrichment in ligands can also be achieved by directly conjugating a synthetic myocardium targeting peptide, such as the cardiac homing peptide (CHP), to the surface of intravenously infused CSC‐derived exosomes . In addition, cells labelled with superparamagnetic nanoparticle can be guided to the injury site by an external magnetic field placed above the heart during the injection enhancing the retention/engraftment in the damaged area and multiplying the therapeutic benefit .…”