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Updated: Oct 30, 2025
Mitigation of Blood Borne Cell Attachment to Metal Implants through CD47-Derived Peptide Immobilization
Published on: December 3, 2020
Mononuclear phagocyte system blockade using extracellular vesicles modified with CD47 on membrane surface for
Zilun Wei1, Zhaoyang Chen2, Yongchao Zhao3
1Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital, Fudan University, Shanghai, China; Institute of Biomedical Science, Fudan University, Shanghai, China; Department of Cardiology, Nanjing Drum Tower Hospital, Clinical College of Nanjing Medical University, Nanjing, China.
Abstract:
Mesenchymal stem cell (MSC)-derived extracellular vesicles (EVs) with anti-apoptotic and anti-inflammatory properties have been intensively studied. However, rapid clearance by the mononuclear phagocyte system remains a huge barrier for the delivery of extracellular vesicle contents into target organs and restricts its wider application, particularly in the heart. CD47 is a transmembrane protein that enables cancer cells to evade clearance by macrophages through CD47- signal regulatory proteinα binding, which initiates a "don't eat me" signal. This study aimed to explore the biodistribution and delivery efficiency of EVs carrying the membrane protein CD47 and specific anti-apoptotic miRNAs. EVs were isolated from MSCs overexpressing CD47 (CD47-EVs) and identified. Fluorescence-labeled EVs were injected through the tail vein and tracked using fluorescence imaging. In silico analysis was performed to determine miRNA profiles in MSCs and in a heart-derived H9c2 cardiomyoblast cell line under hypoxia vs. normoxia conditions. Electro CD47-EV was constructed by encapsulating purified CD47-EV with miR-21a via electroporation. The effect of miR21-EVs on the pro-apoptotic gene encoding phosphatase and tensin homolog (PTEN) was evaluated by dual-luciferase assay, qPCR, and western blotting. Exogenous miR21 distribution, PTEN protein level, blood vessel density, anti-apoptotic effect by TdT-mediated dUTP nick-end labeling staining, and macrophage and leukocyte infiltration in the myocardium were assessed by immunofluorescence staining. Cardiac functional recovery during the early stage and recovery period was evaluated using echocardiography. The results showed that CD47-EVs were still detectable in the plasma 120 min after the tail vein injection, compared to the detection time of less than 30 min observed with the unmodified EVs. More strikingly, CD47-EVs preferentially accumulated in the heart in the ischemia-reperfusion (I/R) + CD47-EV group [heart total fluorescence radiance ( × 105 Photons/sec/cm2/sr) 51.62 ± 11.30 v.s. 10.08 ± 3.15 in the I/R + unmodified EVs group] 8 h post-injection. Exogenous miR-21 is efficiently internalized into cardiomyocytes, inhibits apoptosis, alleviates inflammation, and improves cardiac function. In conclusion, electro CD47-EVs efficiently improve biodistribution in the heart, shedding new light on the application of a two-step EV delivery method (CD47 genetic modification followed by therapeutic content electrotransfection) as a potential therapeutic tool for myocardial I/R injury that may benefit patients in the future.
Insights
Modified extracellular vesicles (EVs) evade rapid clearance, improving delivery to the heart for treating myocardial injury. CD47-modified EVs carrying anti-apoptotic microRNAs enhance cardiac function and reduce inflammation.
Area of Science:
- Biomedical Engineering
- Regenerative Medicine
- Cardiovascular Research
Background:
- Mesenchymal stem cell (MSC)-derived extracellular vesicles (EVs) show therapeutic potential due to anti-apoptotic and anti-inflammatory properties.
- Rapid clearance of EVs by the mononuclear phagocyte system limits their efficacy, especially for cardiac applications.
- CD47 protein can mediate a "don't eat me" signal, potentially prolonging EV circulation time and improving target organ delivery.
Purpose of the Study:
- To investigate the biodistribution and delivery efficiency of CD47-modified EVs (CD47-EVs) for enhanced cardiac targeting.
- To evaluate the therapeutic efficacy of CD47-EVs loaded with anti-apoptotic microRNAs (miRNAs) in a myocardial ischemia-reperfusion (I/R) injury model.
- To explore a novel two-step EV delivery strategy combining CD47 modification and therapeutic cargo electroporation.
Main Methods:
- MSCs were genetically engineered to overexpress CD47, and resulting CD47-EVs were characterized.
- Fluorescence-labeled EVs (unmodified and CD47-modified) were injected intravenously and tracked in vivo.
- In silico analysis identified specific miRNAs (e.g., miR-21a) relevant to cardiac conditions.
- CD47-EVs were loaded with miR-21a via electroporation to create electro CD47-EVs.
- The therapeutic effects were assessed in a rat myocardial I/R model, evaluating apoptosis, inflammation, vascularization, and cardiac function via echocardiography.
Main Results:
- CD47-EVs exhibited significantly prolonged circulation time compared to unmodified EVs (120 min vs. <30 min).
- CD47-EVs demonstrated preferential accumulation in the heart following I/R injury.
- Electro CD47-EVs efficiently delivered miR-21a into cardiomyocytes, leading to PTEN inhibition, reduced apoptosis, and decreased inflammatory cell infiltration.
- Treatment with electro CD47-EVs improved cardiac function and vascular density in the I/R model.
Conclusions:
- CD47 modification enhances EV circulation time and cardiac targeting efficiency.
- The two-step delivery method of CD47 genetic modification followed by therapeutic miRNA electrotransfection is a promising strategy for myocardial I/R injury.
- Engineered EVs offer a potential therapeutic avenue for improving outcomes in cardiovascular diseases.
