Membrane Vesicles as Drug Delivery Systems: Source, Preparation, Modification, Drug Loading, In Vivo Administration and Biodistribution, and Application in Various Diseases

Fibrous scaffolds loaded with BMSC-derived apoptotic vesicles promote wound healing by inducing macrophage polarization

Macrophages play a key role in wound healing. Dysfunction of their M0 polarization to M2 leads to disorders of the wound immune microenvironment and chronic inflammation, which affects wound healing. Regulating the polarization of M0 macrophages to M2 macrophages is an effective strategy for treating wound healing. Mesenchymal stem cells (MSCs) deliver endogenous regulatory factors via paracrine extracellular vesicles, which may play a key role in wound healing, and previous studies have shown that apoptotic bodies (ABs) are closely associated with inflammation regression and macrophage polarization. However, the specific regulatory mechanisms involved in ABs remain unknown. In the present study, we designed an MSC-AB (MSC-derived AB)-loaded polycaprolactone (PCL) scaffold, evaluated the macrophage phenotype and skin wound inflammation in vivo and in vitro, and explored the ability of MSC-AB-loaded PCL scaffolds to promote wound healing. Our data suggest that the PCL scaffold regulates the expression of the CCL-1 gene by targeting the delivery of mmu-miR-21a-5p by local sustained-release MSC-ABs, and drives M0 macrophages to program M2 macrophages to regulate inflammation and angiogenesis, thereby synergistically promoting wound healing. This study provides a promising therapeutic strategy and experimental basis for treating various diseases associated with imbalances in proinflammatory and anti-inflammatory immune responses.

Identification of key miRNAs and target genes in extracellular vesicles derived from low-intensity pulsed ultrasound-treated stem cells

Objectives

This study aimed to investigate the impact of low-intensity pulsed ultrasound (LIPUS) treatment on the miRNA and mRNA profiles of stem cell-derived extracellular vesicles (EVs). Specifically, it sought to identify key miRNAs and their target mRNAs associated with enhanced therapeutic efficacy in LIPUS-treated stem cell-derived EVs.

Methods

Utilizing miRNA deep-sequencing data from the Gene Expression Omnibus database, differential gene analysis was performed. MiRNA-mRNA target analysis, functional and pathway enrichment analysis, protein-protein interaction network construction, and hub gene identification were conducted. Validation of differentially expressed miRNAs was performed via RT-qPCR in human umbilical cord mesenchymal stem cells (hUC-MSCs) treated with LIPUS.

Results

Ten differentially expressed miRNAs were identified, with six upregulated and four downregulated miRNAs in LIPUS-treated stem cell-derived EVs. Functional enrichment analysis revealed involvement in biological processes such as regulation of metabolic processes, cellular component organization, and response to stress, as well as signaling pathways like cell cycle, MAPK signaling, and Hippo signaling. Protein-protein interaction network analysis identified key hub genes including MYC, GAPDH, HSP90AA1, EP300, JUN, PTEN, DAC1, STAT3, HSPA8, and HIF1A associated with LIPUS treatment. RT-qPCR validation confirmed differential expression of selected miRNAs (hsa-miR-933, hsa-miR-3943, hsa-miR-4633-5p, hsa-miR-592, hsa-miR-659-5p, hsa-miR-4766-3p) in LIPUS-treated hUC-MSCs.

Conclusion

This study sheds light on the potential therapeutic mechanisms underlying LIPUS-treated stem cell-derived EVs. The identified differentially expressed miRNAs and their potential target mRNAs offer valuable insights into the biological processes influenced by LIPUS treatment. While further investigation is necessary to validate their roles as therapeutic targets, this study lays the groundwork for future research on optimizing SC-EV therapy with LIPUS preconditioning.

Analysis of lipid composition of cell-bound membrane vesicles (CBMVs) derived from endothelial cells

Cell-bound membrane vesicles (CBMVs), a novel type of membrane vesicles, have been identified through a series of characterization tools. However, the lipid composition of CBMVs has not yet been characterized. This study focuses on the differences in lipid composition between CBMVs and cell membranes. In order to determine the lipid composition of CBMVs and cell membranes of Human umbilical vein endothelial cells (HUVECs) and find out differential metabolites, this study was carried out by isolating CBMVs lipids and characterizing them using high-performance liquid chromatography tandem secondary mass spectrometry (LC-MS/MS). The results showed the presence of 213 up-regulated and 726 down-regulated lipids in CBMVs compared to cell membranes which produced CBMVs. There are lipids expressed in CBMVs and not in cell membranes: DGDG 18:0_8:0, DGDG O-8:0_16:1, DGDG O-26:7_26:7, DGDG O-16:3_26:7, TG 15:4_21:5_22:5; 4O, PC 49:11, PG 19:5_38:10, PI 60:14, PI 44:9, PI 25:2, PI 43:5, PI 50:10, PS 55:10. DGDG (digalactosyl diglyceride), MGDG (monogalactosyl diglyceride) belongs to galactosyl diglyceride, promotes fat catabolism, which also has antioxidant and anti-inflammatory effects, and unsaturated diacylglycerols are a class of antioxidant compounds, which enables CBMVs to have a therapeutic potential.

Minimal Information for Studies of Extracellular Vesicles (MISEV): Ten-Year Evolution (2014-2023)

In the tenth year since the first edition of MISEV was released in 2014, MISEV2023 has been reported in 2024 with the aim of refining the standard and improving the rigor, reproducibility, and transparency of extracellular vesicle (EV) research to clarify the requirements for experimental design of EVs, emphasize the importance of reproducible experimental results as well as encouraging openness of experimental information. The release of MISEV has significantly contributed to the quality of research in the field of EVs, which creates a more reliable research environment. However, despite the important role of MISEV, there is still a need for the EV researchers to continue to push for the widespread implementation of the guidelines to meet the evolving nature and challenges of EV research. The evolution of EV research and the attention it receives have grown exponentially over time, as has the number of people involved in the writing of MISEV. Here, this review briefly summarizes the evolution of the three editions of MISEV, aiming to recall MISEV2014 and MISEV2018 while learning about the latest release, MISEV2023, to gain a deeper understanding of the content, and to provide a quick note for beginners who want to learn about MISEV and explore the EV world.

Delivery of neurotrophin-3 by RVG-Lamp2b-modified mesenchymal stem cell-derived exosomes alleviates facial nerve injury

We aim to investigate the effect of RVG-Lamp2b-modified exosomes (exos) loaded with neurotrophin-3 (NT-3) on facial nerve injury. Exos were collected from control cells (Ctrl Exo) or bone marrow mesenchymal stem cells co-transfected with RVG-Lamp2b and NT-3 plasmids (RVG-NT-3 Exo) by gradient centrifugation and identified by western blotting, transmission electron microscopy, and nanoparticle tracking analysis. Effect of RVG-NT-3 Exo on oxidative stress damage was determined by analysis of the morphology, viability, and ROS production of neurons. Effect of RVG-NT-3 Exo on facial nerve axotomy (FNA) was determined by detecting ROS production, neuroinflammatory reaction, microglia activation, facial motor neuron (FMN) death, and myelin sheath repair. Loading NT-3 and modifying with RVG-Lamp2b did not alter the properties of the exos. Moreover, RVG-NT-3 Exo could effectively target neurons to deliver NT-3. Treatment with RVG-NT-3 Exo lowered H2O2-induced oxidative stress damage in primary neurons and Nsc-34 cells. RVG-NT-3 Exo treatment significantly decreased ROS production, neuroinflammatory response, FMN death, and elevated microglia activation and myelin sheath repair in FNA rat models. Our findings suggested that RVG-NT-3 Exo-mediated delivery of NT-3 is effective for the treatment of facial nerve injury.

Exosome: From biology to drug delivery

In recent years, different advancements have been observed in nanosized drug delivery systems. Factors such as stability, safety and targeting efficiency cause hindrances in the clinical translation of these synthetic nanocarriers. Therefore, researchers employed endogenous nanocarriers like exosomes as drug delivery vehicles that have an inherent ability to target more efficiently after appropriate functionalization and show higher biocompatibility and less immunogenicity and facilitate penetration through the biological barriers more quickly than the other available carriers. Exosomes are biologically derived lipid bilayer-enclosed nanosized extracellular vesicles (size ranges from 30 to 150 nm) secreted from both prokaryotic and eukaryotic cells and appears significantly in the extracellular space. These EVs (extracellular vesicles) can exist in different sources, including mammals, plants and microorganisms. Different advanced techniques have been introduced for the isolation of exosomes to overcome the existing barriers present with conventional methods. Extensive research on the application of exosomes in therapeutic delivery for treating various diseases related to central nervous system, bone, cancer, skin, etc. has been employed. Several studies are on different stages of clinical trials, and many exosomes patents have been registered.

Thermosensitive Capturer Coupled with the CD63 Aptamer for Highly Efficient Isolation of Exosomes

Exosomes are bioactive substances secreted by various cells that play a crucial role in cell communication. Due to their nanoscale size and interference from nonexosome proteins, the rapid capture and nondestructive release of exosomes remain a technical challenge which significantly hinders their biomedical application. To overcome this obstacle, we have designed a CD63 aptamer-based thermosensitive copolymer for the effective isolation of exosomes from mesenchymal stem cells (MSCs). A thermal-responsive copolymer, poly(N-isopropylacrylamide-co-butyl methacrylate-co-N-hydroxysuccinimide methacrylate) P(NIPAM-co-BMA-co-NHSMA, PNB), was prepared, which could realize reversible hydrophilic/hydrophobic phase transition by varying temperature. Then, CD63 aptamers were further modified to the copolymer to form the PNB-aptamer, where the aptamer units, acting as a "lock and key", specifically bind exosomes. Under the low critical solution temperature (LCST) of the PNB-aptamer, it can maintain a hydrophilic state, capturing exosomes from the cell culture medium. Subsequently, exosome-carrying PNB-aptamers can endure from hydrophilic to hydrophobic phase transition by increasing the temperature above its LCST, and then they can be collected after centrifugation. By introducing the complementary sequence of the CD63 aptamer, the stronger binding affinity between the complementary sequence and the aptamers facilitates the release of exosomes from the PNB-aptamer. The yield of exosome samples captured from a MSC culture medium by the PNB-aptamer system (around 62%) is considerably higher than that obtained by the current "gold standard" ultrafiltration (UC) approach (around 42%). Thus, the PNB-aptamer capturer provides a potential strategy for highly efficient exosome isolation.