Macrophage-derived extracellular vesicles represent a promising endogenous iron-chelating therapy for iron overload and cardiac injury in myocardial infarction.

BACKGROUND: Cardiac iron overload and ferroptosis greatly contribute to the poor prognosis of myocardial infarction (MI). Iron chelator is one of the most promising strategies for scavenging excessive iron and alleviating cardiac dysfunction post MI. However, various side effects of existing chemical iron chelators restrict their clinical application, which calls for a more viable and safer approach to protect against iron injury in ischemic hearts. RESULTS: In this study, we isolated macrophage-derived extracellular vesicles (EVs) and identified macrophage-derived EVs as a novel endogenous biological chelator for iron. The administration of macrophage-derived EVs effectively reduced iron overload in hypoxia-treated cardiomyocytes and hearts post MI. Moreover, the oxidative stress and ferroptosis induced by excessive iron were considerably suppressed by application of macrophage-derived EVs. Mechanistically, transferrin receptor (TfR), which was inherited from macrophage to the surface of EVs, endowed EVs with the ability to bind to transferrin and remove excess protein-bound iron. EVs with TfR deficiency exhibited a loss of function in preventing MI-induced iron overload and protecting the heart from MI injury. Furthermore, the iron-chelating EVs were ultimately captured and processed by macrophages in the liver. CONCLUSIONS: These results highlight the potential of macrophage-derived EVs as a powerful endogenous candidate for iron chelation therapy, offering a novel and promising therapeutic approach to protect against iron overload-induced injury in MI and other cardiovascular diseases.

Improved extracellular vesicle-based mRNA delivery for familial hypercholesterolemia treatment.

Extracellular vesicle (EV)-based low-density lipoprotein receptor (Ldlr) mRNA delivery showed excellent therapeutic effects in treating familial hypercholesterolemia (FH). Nevertheless, the loading inefficiency of EV-based mRNA delivery presents a significant challenge. Recently, RNA-binding proteins (RBPs) have been fused to EV membrane proteins for selectively encapsulating targeted RNAs to promote loading efficiency. However, the strong interaction between therapeutic RNAs and RBPs prevents RNA release from endosomes to the cytosol in the recipient cells. In this study, an improved strategy was developed for efficient encapsulation of Ldlr mRNA into EVs in donor cells and controllable release in recipient cells. Methods: The MS2 bacteriophage coat protein (CD9-MCP) fusion protein, Ldlr mRNA, and a customized MS2 containing RNA aptamer base-pair matched with Ldlr mRNA were expressed in donor cells. Cells receiving the above therapeutic EVs were simultaneously treated with EVs containing "Ldlr releaser" with a sequence similar to the recognition sites in Ldlr mRNA. Therapeutic effects were analyzed in Ldlr-/- mice receiving EV treatments via the tail vein. Results: In vitro experiments demonstrated improved loading efficiency of Ldlr mRNA in EVs via MS2-MCP interaction. Treatment of "Ldlr releaser" competitively interacted with MS2 aptamer with higher affinity and released Ldlr mRNA from CD9-MCP for efficient translation. When the combinatory EVs were delivered into recipient hepatocytes, the robust LDLR expression afforded therapeutic benefits in Ldlr-/- mice. Conclusion: We proposed an EV-based mRNA delivery strategy for enhanced encapsulation of therapeutic mRNAs in EVs and RNA release into the cytosol for translation in recipient cells with great potential for gene therapy.

Associations of human papillomavirus genotypes and cervical vascular abnormality in a cohort of women underwent colposcopy, a retrospective study of 6716 patients.

Aims: Abnormal vessel patterns are specific signs in patients with early cervical abnormality and cervical cancer(CC) by colposcopy, but the impact of human papillomavirus (HPV) infections on abnormal vessel patterns remains unknown. Methods: A total of 6716 female patients with HPV infections or cytological abnormalities who underwent a colposcopy following abnormal CC screening results were included in the study. The final pathological diagnosis was confirmed to be the most severe pathological grade across cervical biopsy, endocervical canal curettage (ECC) and conization. Univariate and multivariate logistic regression analyses were used to investigate the association between HPV infections and abnormal vessel patterns, adjusting for age, gravidity and parity. Results: There were 6124 normal vascular cases by colposcopy and 592 cases with cervical vascular abnormality. The prevalence of HPV infections was 4284 (70%) in normal patients, and the prevalence of HPV infections was 479 (80%) in cervical vascular abnormality patients. HPV high-risk type 16 infection alone increased the risk of cervical heteromorphic blood vessels (aOR=3.66, 95%CI: 2.54~5.27). HPV 16 and 33 alone (other than the commonly recognized subtype of 18) or coinfection of these two genotypes could increase the risk of cervical punctate vascular and cervical vascular mosaic features and abnormal cervical blood vessels. An increased risk of abnormal cervical lesions was observed for HPV 16 and 33 alone or combined in coinfection compared to the negative group. The risk of cervical vascular abnormality was increased 10-fold by coinfection with HPV 16 and 33 (aOR=10.67, 95% CI: 4.54~25.09, P<0.001). HPV 16, 33 alone or combined in coinfection were associated with an increased risk of lesions more advanced than high-grade squamous intraepithelial lesion (HSIL) when compared to the negative group. The risk of lesions more advanced than HSIL was up to 26-fold higher in the coinfection with HPV 16 and 33 group than in the negative group (aOR=26.23, 95%CI: 11.23~61.27, P<0.001). Conclusion: HPV16 and 33 are the most dangerous HPV genotypes correlated with abnormal vascular patterns. Combined HPV16 and HPV33 infection increases the risk of abnormal vascular patterns. Combined HPV16 and HPV33 infection increases the risk of developing HSIL+.

Ultrasound Responsive Nanovaccine Armed with Engineered Cancer Cell Membrane and RNA to Prevent Foreseeable Metastasis.

Cancer vaccine has been considered as a promising immunotherapy by inducing specific anti-tumor immune response. Rational vaccination at suitable time to efficiently present tumor associated antigen will boost tumor immunity and is badly needed. Here, a poly (lactic-co-glycolic acid) (PLGA)-based cancer vaccine of nanoscale is designed, in which engineered tumor cell membrane proteins, mRNAs, and sonosensitizer chlorin e6 (Ce6) are encapsulated at high efficiency. The nanosized vaccine can be efficiently delivered into antigen presentation cells (APCs) in lymph nodes after subcutaneous injection. In the APCs, the encapsulated cell membrane and RNA from engineered cells, which have disturbed splicing resembling the metastatic cells, provide neoantigens of metastatic cancer in advance. Moreover, the sonosensitizer Ce6 together with ultrasound irradiation promotes mRNA escape from endosome, and augments antigen presentation. Through 4T1 syngeneic mouse model, it has been proved that the proposed nanovaccine is efficient to elicit antitumor immunity and thus prevent cancer metastasis.

"All-in-One" Exosome Engineering Strategy for Effective Therapy of Familial Hypercholesterolemia.

Exosomes serve as a promising therapeutic nanoplatform. However, the exosomes produced by donor cells are a heterogeneous group, with only a small portion having high therapeutic efficacy. Specific isolation of the subpopulation with high efficacy is important for lowering the dose and minimizing toxicity. In this study, we loaded target mRNA and displayed specific Flag in engineered exosomes simultaneously. Briefly, the donor cells were transfected with plasmid expressing a fusion protein Flag-TCS-PTGFRN-CTSL-MCP, namely, exosome sorter. During biogenesis, the RNA-binding motif MCP can specifically bind with MS2-containing RNA and sort the target RNA into the lumen of exosomes. Anti-Flag magnetic beads can capture and thus purify the engineered exosomes via recognition of the Flag on the surface of exosomes. After purification, the Flag could be cleaved by thrombin treatment while MCP can be separated from the fusion protein by CTSL autocleavage upon exosome acidification, minimizing the side effects and augmenting the therapeutic effects. By the proof-of-concept experiment, the exosome sorter-based "all-in-one" strategy was confirmed effective in both the encapsulation of therapeutic mRNA (Ldlr-MS2) into exosomes and the subsequent purification. The purified Ldlr-MS2-containing exosomes had much higher efficacy in alleviating atherosclerosis, in comparison with the bulk exosomes, confirming the advantage of the proposed "all-in-one" strategy.

Early Assessment of Atherosclerotic Lesions and Vulnerable Plaques in vivo by Targeting Apoptotic Macrophages with AV Nanobubbles.

Background: The early detection of atherosclerotic lesions is particularly important for risk prediction of acute cardiovascular events. Macrophages apoptosis was significantly associated with the degree of AS lesions and especially contributed to plaque vulnerability. In this research, we mainly sought to explore the feasibility of a home-made AV-nanobubbles (NBAV) for visualization of apoptotic macrophages and assessment of atherosclerosis (AS) lesions by contrast-enhanced ultrasound (CEUS) imaging. Methods: NBAV were prepared by "Optimized Thin-Film Hydration" and "Biotin-Avidin-Biotin" methods. Then, the characterization and echogenicity of NBAV were measured and analyzed in vitro. The targeting ability of NBAV to ox-LDL-induced apoptotic macrophages was observed by laser scanning confocal microscope. The ApoE-/- mice mode fed with high fat diet were observed by high-frequency ultrasound, microanatomy and oil red O staining. CEUS imaging in vivo was performed on AS plaques with NBAV and NBCtrl injection through the tail vein in turn in ApoE-/- mice. After CEUS imaging, the plaques were confirmed and analyzed by histopathological and immunological assessment. Results: The prepared NBAV had a nano-scale size distribution with a low PDI and a negative zeta potential. Moreover, NBAV showed an excellent stability and exhibited a significantly echogenic signal than saline in vitro. In addition, we found that NBAV could target apoptotic macrophages induced by ox-LDL. Compared with NBCtrl, CEUS imaging of NBAV showed strong and sustained echo enhancement in plaque area of aortic arch in vivo. Further research showed that NBAV sensitive plaques presented more significant pathological changes with several vulnerable plaque features and abundant TUNEL-positive area. Conclusion: NBAV displayed a sensitive indicator to evaluate apoptotic macrophages, indicating a promising CEUS molecular probe for AS lesions and vulnerable plaques identification.

Exosome-mediated delivery of inflammation-responsive Il-10 mRNA for controlled atherosclerosis treatment.

Rationale: Tailored inflammation control is badly needed for the treatment of kinds of inflammatory diseases, such as atherosclerosis. IL-10 is a potent anti-inflammatory cytokine, while systemic and repeated delivery could cause detrimental side-effects due to immune repression. In this study, we have developed a nano-system to deliver inflammation-responsive Il-10 mRNA preferentially into macrophages for tailored inflammation control. Methods:Il-10 was engineered to harbor a modified HCV-IRES (hepatitis C virus internal ribosome entry site), in which the two miR-122 recognition sites were replaced by two miR-155 recognition sites. The translational responsiveness of the engineered mRNA to miR-155 was tested by Western blot or ELISA. Moreover, the engineered Il-10 mRNA was passively encapsulated into exosomes by forced expression in donor cells. Therapeutic effects on atherosclerosis and the systemic leaky expression effects in vivo of the functionalized exosomes were analyzed in ApoE-/- (Apolipoprotein E-deficient) mice. Results: The engineered IRES-Il-10 mRNA could be translationally activated in cells when miR-155 was forced expressed or in M1 polarized macrophages with endogenous miR-155 induced. In addition, the engineered IRES-Il-10 mRNA, when encapsulated into the exosomes, could be efficiently delivered into macrophages and some other cell types in the plaque in ApoE-/- mice. In the recipient cells of the plaque, the encapsulated Il-10 mRNA was functionally translated into protein, with relatively low leaky in other tissues/organs without obvious inflammation. Consistent with the robust Il-10 induction in the plaque, exosome-based delivery of the engineered Il-10 could alleviate the atherosclerosis in ApoE-/- mice. Conclusion: Our study established a potent platform for controlled inflammation control via exosome-based systemic and repeated delivery of engineered Il-10 mRNA, which could be a promising strategy for atherosclerosis treatment.

HIF1α epigenetically repressed macrophages via CRISPR/Cas9-EZH2 system for enhanced cancer immunotherapy.

Immune suppressive microenvironment in tumor emerges as the main obstacle for cancer immunotherapy. In this study, we identified that HIF1α was activated in the tumor associated macrophages and acted as an important factor for the immune suppressive microenvironment. Epigenetically silencing of Hif1α via histone H3 methylation in the promoter region was achieved by CRISPR/dCas9-EZH2 system, in which histone H3 methylase EZH2 was recruited to the promoter region specifically. The Hif1α silenced macrophage, namely HERM (Hif1α Epigenetically Repressed Macrophage) manifested as inheritable tumor suppressing phenotype. In the subcutaneous B16-F10 melanoma syngeneic model, intratumoral injection of HERMs reprogrammed the immune suppressive microenvironment to the active one, reducing tumor burden and prolonging overall survival. Additionally, HERMs therapy remarkably inhibited tumor angiogenesis. Together, our study has not only identified a promising cellular and molecular target for reverting immune suppressive microenvironment, but also provided a potent strategy for reprogramming tumor microenvironment via epigenetically reprogrammed macrophages.

Exosomes in atherosclerosis: performers, bystanders, biomarkers, and therapeutic targets.

Exosomes are nanosized lipid vesicles originating from the endosomal system that carry many macromolecules from their parental cells and play important roles in intercellular communication. The functions and underlying mechanisms of exosomes in atherosclerosis have recently been intensively studied. In this review, we briefly introduce exosome biology and then focus on advances in the roles of exosomes in atherosclerosis, specifically exosomal changes associated with atherosclerosis, their cellular origins and potential functional cargos, and their detailed impacts on recipient cells. We also discuss the potential of exosomes as biomarkers and drug carriers for managing atherosclerosis.

Exosome-based Ldlr gene therapy for familial hypercholesterolemia in a mouse model.

Familial hypercholesterolemia (FH), with high LDL (low-density lipoprotein) cholesterol levels, is due to inherited mutations in genes, such as low-density lipoprotein receptor (LDLR). Development of therapeutic strategies for FH, which causes atherosclerosis and cardiovascular disease, is urgently needed. Methods: Mice with low-density lipoprotein receptor (Ldlr) deletion (Ldlr-/- mice) were used as an FH model. Ldlr mRNA was encapsulated into exosomes by forced expression of Ldlr in the donor AML12 (alpha mouse liver) cells, and the resultant exosomes were denoted as ExoLdlr. In vivo distribution of exosomes was analyzed by fluorescence labeling and imaging. The delivery efficiency of Ldlr mRNA was analyzed by qPCR and Western blotting. Therapeutic effects of ExoLdlr were examined in Ldlr-/- mice by blood lipids and Oil Red O staining. Results: The encapsulated mRNA was stable and could be translated into functional protein in the recipient cells. Following tail vein injection, exosomes were mainly delivered into the liver, producing abundant LDLR protein, resembling the endogenous expression profile in the wild-type mouse. Compared with control exosomes, ExoLdlr treatment significantly decreased lipid deposition in the liver and lowered the serum LDL-cholesterol level. Significantly, the number and size of atherosclerotic plaques and inflammation were reduced in the ExoLdlr-treated mice. Conclusions: We have shown that exosome-mediated Ldlr mRNA delivery effectively restored receptor expression, treating the disorders in the Ldlr-/- mouse. Our study provided a new therapeutic approach for the treatment of FH patients and managing atherosclerosis.

Ultrasound targeted microbubble destruction assisted exosomal delivery of miR-21 protects the heart from chemotherapy associated cardiotoxicity.

Chemotherapy related cardiotoxicity is now becoming one of the biggest hurdles for the prognosis of cancer patients. Therapeutically delivering protective small RNAs holds promise for the cardiotoxicity prevention and therapy. However, heart is intrinsically refractory to the nanoparticle-mediated drug delivery. In this study, we found that the exosome-mediated miRNA delivery into the heart could be significantly augmented with the aid of ultrasound targeted microbubble destruction (UTMD). Moreover, we found that UTMD assisted exosomal miR-21 delivery into the heart significantly decreased the cell death, and restored the cardiac function in a doxorubicin induced cardiotoxicity mouse model. Our study here not only provides a promising strategy to protect the heart from the chemotherapy related cardiotoxicity, but also sheds light on gene therapy of other heart diseases.

Chronic myelogenous leukemia cells remodel the bone marrow niche via exosome-mediated transfer of miR-320.

Rationale: Reciprocal interactions between leukemic cells and bone marrow mesenchymal stromal cells (BMMSC) remodel the normal niche into a malignant niche, leading to leukemia progression. Exosomes have emerged as an essential mediator of cell-cell communication. Whether leukemic exosomes involved in bone marrow niche remodeling remains unknown. Methods: We investigated the role of leukemic exosomes in molecular and functional changes of BMMSC in vitro and in vivo. RNA sequencing and bioinformatics were employed to screen for miRNAs that are selectively sorted into leukemic exosomes and the corresponding RNA binding proteins. Results: We demonstrated that leukemia cells significantly inhibited osteogenesis by BMMSC both in vivo and in vitro. Some tumor suppressive miRNAs, especially miR-320, were enriched in exosomes and thus secreted by leukemic cells, resulting in increased proliferation of the donor cells. In turn, the secreted exosomes were significantly endocytosed by adjacent BMMSC and thus inhibited osteogenesis at least partially via ß-catenin inhibition. Mechanistically, miR-320 and some other miRNAs were sorted out into the exosomes by RNA binding protein heterogeneous nuclear ribonucleoprotein A1 (HNRNPA1), as these miRNAs harbor the recognition site for HNRNPA1. Conclusion: HNRNPA1-mediated exosomal transfer of miR-320 from leukemia cells to BMMSC is an important mediator of leukemia progression and is a potential therapeutic target for CML.

In Vitro and in Vivo RNA Inhibition by CD9-HuR Functionalized Exosomes Encapsulated with miRNA or CRISPR/dCas9.

In vitro and in vivo delivery of RNAs of interest holds promise for gene therapy. Recently, exosomes are considered as a kind of rational vehicle for RNA delivery, especially miRNA and/or siRNA, while the loading efficiency is limited. In this study, we engineered the exosomes for RNA loading by constructing a fusion protein in which the exosomal membrane protein CD9 was fused with RNA binding protein, while the RNA of interest either natively harbors or is engineered to have the elements for the binding. By proof-of-principle experiments, we here fused CD9 with HuR, an RNA binding protein interacting with miR-155 with a relatively high affinity. In the exosome packaging cells, the fused CD9-HuR successfully enriched miR-155 into exosomes when miR-155 was excessively expressed. Moreover, miR-155 encapsulated in the exosomes in turn could be efficiently delivered into the recipient cells and recognized the endogenous targets. In addition, we also revealed that the CD9-HuR exosomes could enrich the functional miRNA inhibitor or CRISPR/dCas9 when the RNAs were engineered to have the AU rich elements. Taken together, we here have established a novel strategy for enhanced RNA cargo encapsulation into engineered exosomes, which in turn functions in the recipient cells.