Tarvirdizadeh, T. | bioRxiv Science

bioRxiv2022

Surface engineering enhances the therapeutic potential of extracellular vesicles following acute myocardial infarction

Structured AbstractO_ST_ABSObjectivesC_ST_ABSThe objective of the study was to assess the therapeutic efficacy of targeting remote zone cardiomyocytes with cardiosphere-derived cell (CDC) extracellular vesicles (EVs) in acute myocardial infarction. BackgroundCardiomyocyte (CM) cell death plays a significant role in left ventricular (LV) remodeling and cardiac dysfunction following myocardial infarction (MI). While EVs secreted by CDCs have shown efficacy in promoting cardiac repair in preclinical models of MI, their translational potential is limited by their biodistribution. We hypothesized that targeting therapeutic EVs to CMs would result in further reduction of cardiomyocyte (CM) cell death in vivo and improvement in cardiac function post-MI. MethodsCDC-derived EVs were engineered to express a CM-specific binding peptide (CMP) on their surface and characterized for size, morphology, and protein expression. Mice with acute MI underwent delivery of human CDC EVs, CMP-EVs and placebo in a double-blind study. LVEF was assessed by echo at 1- and 28-days post-MI and tissue samples processed for assessment of EV biodistribution and histological endpoints. ResultsCMP-EVs demonstrated superior cardiac targeting and retention when compared with control EVs 24 hours post MI. While intramyocardial administered CDC-EVs improved LVEF compared with placebo at 4 weeks, mice treated with CMP-EVs demonstrated a significant improvement in LVEF compared with non-targeted EVs. Likely accounting for their augmented therapeutic efficacy, CMP-EVs demonstrated enhanced reduction of remote zone cardiomyocyte apoptosis. ConclusionsTargeting CMP-EVs to CMs post-MI improved cardiac function compared with unmodified EVs demonstrating a strategy to further optimize therapeutic EV delivery to increase efficacy and decease off-target effects. Condensed AbstractExtracellular vesicles (EVs) offer several potential advantages over small molecule therapeutics for cardiovascular disease (CVD). However, their potential is limited by their biodistribution and lack of specificity. We engineered cardiosphere-derived cells (CDCs) to express Lamp2b fused to a cardiomyocyte specific peptide (CMP), generating EVs with increased cardiomyocyte uptake and cardiac retention. CMP-EVs enhanced cardiac function following acute MI and further reduced remote zone apoptosis when compared with unmodified CDC-EVs. This work highlights a role for targeting therapeutic EVs to cardiomyocytes following injury and serves as a proof-of-concept study for the utility of EV surface engineering in the treatment of CVD.

bioengineering↗

bioRxiv2022

Extracellular vesicle microRNA cargo engineering reveals critical mechanisms underlying therapeutic efficacy

BackgroundExtracellular vesicles (EVs) are key mediators of intercellular communication and function to transfer biological cargo, including microRNA (miR), from donor to recipient cells. EVs isolated from cardiosphere-derived cells (CDCs) have demonstrated therapeutic efficacy in pre-clinical models of ischemic heart disease, highlighting them as promising vectors for the treatment of CVD. Importantly, it has not yet been established whether miR cargo is necessary for the observed therapeutic benefit of CDC-EVs following acute MI (AMI). MethodsCDCs were transfected with siRNA against Drosha, the initial endonuclease in the miRNA biogenesis pathway, to generate miR depleted DROSHA-EVs. EVs were characterized by size, morphology, and protein/miR expression. The role of EV miRNA on cardiac target cell apoptosis, proliferation and angiogenesis was examined using a series of in vitro assays. Mice with acute MI underwent delivery of human CDC EVs, DROSHA-EVs and placebo in a double-blind study. LVEF was assessed by echo at 1- and 28-days post-MI and tissue samples processed for assessment of histological endpoints. In vitro sufficiency assays were performed using a combinatorial approach with individual candidate miRs to identify clusters exhibiting synergistic efficacy. ResultsDROSHA-EVs exhibited global downregulation of miRNA cargo but were otherwise indistinguishable from wild-type CDC-EVs. miR cargo was responsible for mediating the beneficial effects of human CDC-EV treatment on cardiomyocyte apoptosis, fibroblast proliferation and angiogenesis in vitro. DROSHA-EVs were unable to promote recovery following AMI on a functional or histological level, highlighting the critical role of EV miRNAs in cardioprotection following ischemic injury. A potentially therapeutic miR cluster, miR-146a-370-126a, was identified which acted synergistically to reduce cardiomyocyte apoptosis and was sufficient to render inert EVs into therapeutic vectors. ConclusionsThese results demonstrate for the first time that miRNAs are required for the regenerative potential of CDC-EVs following AMI and identify a novel miR cluster with therapeutic implications.

bioengineering↗