Extracellular communication between brain cells through functional transfer of Cre mRNA mediated by extracellular vesicles

Extracellular vesicles as drug and gene delivery vehicles in central nervous system diseases

Extracellular vesicles (EVs) are secreted by almost all cell types and contain DNA, RNA, proteins, lipids and other metabolites. EVs were initially believed to be cellular waste but now recognized for their role in cell-to-cell communication. Later, EVs from immune cells were discovered to function similarly to their parent cells, paving the way for their use as gene and drug carriers. EVs from different cell types or biological fluids carry distinct cargo depending on their origin, and they perform diverse functions. For instance, EVs derived from stem cells possess pluripotent properties, reflecting the cargo from their parent cells. Over the past two decades, substantial preclinical and clinical research has explored EVs-mediated drug and gene delivery to various organs, including the brain. Natural or intrinsic EVs may be effective for certain applications, but as drug or gene carriers, they demonstrate broader and more efficient potential across various diseases. Here, we review research on using EVs to treat central nervous system (CNS) diseases, such as Alzheimer's Disease, Parkinson diseases, depression, anxiety, dementia, and acute ischemic strokes. We first reviewed the naïve EVs, especially mesenchymal stem cell (MSC) derived EVs in CNS diseases and summarized the clinical trials of EVs in treating CNS diseases and highlighted the reports of two complete trials. Then, we overviewed the preclinical research of EVs as drug and gene delivery vehicles in CNS disease models, including the most recent two years' progress and discussed the mechanisms and new methods of engineered EVs for targeting CNS. Finally, we discussed challenges and future directions and of EVs as personalized medicine for CNS diseases.

Maternal milk cell components are uptaken by infant liver macrophages via extracellular vesicle mediated transport

Milk is a multifaceted biofluid that is essential for infant nutrition and development, yet its cellular and bioactive components, particularly maternal milk cells, remain understudied. Early research on milk cells indicated that they cross the infant's intestinal barrier and accumulate within systemic organs. However, due to the absence of modern analytical techniques, these studies were limited in scope and mechanistic analysis. To overcome this knowledge gap, we have investigated the transintestinal transport of milk cells and components in pups over a 21-day period. Studies employed a mT/mG foster nursing model in which milk cells express a membrane-bound fluorophore, tdTomato. Using flow cytometry, we tracked the transport of milk cell-derived components across local and systemic tissues, including the intestines, blood, thymus, mesenteric lymph nodes, and liver. These experiments identified milk-derived fluorescent signals in intestinal epithelial and immune cells as well as liver macrophages in 7-day-old pups. However, the minute numbers of macrophages in mouse milk suggest that maternal cells are not systemically accumulating in the infant; instead, pup macrophages are consuming milk cell membrane components, such as apoptotic bodies or extracellular vesicles (EVs). Ex vivo experiments using primary macrophages support this hypothesis, showing that immune cells preferentially consumed EVs over milk cells. Together, these data suggest a more complex interplay between milk cells and the infant's immune and digestive systems than previously recognized and highlight the need for future research on the role of milk cells in infant health.

Extracellular Vesicle lncRNAs as Key Biomolecules for Cell-to-Cell Communication and Circulating Cancer Biomarkers

Extracellular vesicles (EVs) are secreted by almost every cell type and are considered carriers of active biomolecules, such as nucleic acids, proteins, and lipids. Their content can be uptaken and released into the cytoplasm of recipient cells, thereby inducing gene reprogramming and phenotypic changes in the acceptor cells. Whether the effects of EVs on the physiology of recipient cells are mediated by individual biomolecules or the collective outcome of the total transferred EV content is still under debate. The EV RNA content consists of several types of RNA, such as messenger RNA (mRNA), microRNA (miRNA), and long non-coding RNA (lncRNA), the latter defined as transcripts longer than 200 nucleotides that do not code for proteins but have important established biological functions. This review aims to update our insights on the functional roles of EV and their cargo non-coding RNA during cancer progression, to highlight the utility of EV RNA as novel diagnostic or prognostic biomarkers in cancer, and to tackle the technological advances and limitations for EV RNA identification, integrity assessment, and preservation of its functionality.

Abortive and productive infection of CNS cell types following in vivo delivery of VSV

Viral infection is frequently assayed by ongoing expression of viral genes. These assays fail to identify cells that have been exposed to the virus but limit or inhibit viral replication. To address this limitation, we used a dual-labeling vesicular stomatitis virus (DL-VSV), which has a deletion of the viral glycoprotein gene, to allow evaluation of primary infection outcomes. This virus encodes Cre, which can stably mark any cell with even a minimal level of viral gene expression. Additionally, the virus encodes GFP, which distinguishes cells with higher levels of viral gene expression, typically due to genome replication. Stereotactic injections of DL-VSV into the murine brain showed that different cell types had very different responses to the virus. Almost all neurons hosted high levels of viral gene expression, while glial cells varied in their responses. Astrocytes (Sox9+) were predominantly productively infected, while oligodendrocytes (Sox10+) were largely abortively infected. Microglial cells (Iba1+) were primarily uninfected. Furthermore, we monitored the early innate immune response to viral infection and identified unique patterns of interferon (IFN) induction. Shortly after infection, microglia were the main producers of IFNb, whereas later, oligodendrocytes were the main producers. IFNb+ cells were primarily abortively infected regardless of cell type. Last, we investigated whether IFN signaling had any impact on the outcome of primary infection and did not observe significant changes, suggesting that intrinsic factors are likely responsible for determining the outcome of primary infection.

Exploring the potential of cell-derived vesicles for transient delivery of gene editing payloads

Gene editing technologies have the potential to correct genetic disorders by modifying, inserting, or deleting specific DNA sequences or genes, paving the way for a new class of genetic therapies. While gene editing tools continue to be improved to increase their precision and efficiency, the limited efficacy of in vivo delivery remains a major hurdle for clinical use. An ideal delivery vehicle should be able to target a sufficient number of diseased cells in a transient time window to maximize on-target editing and mitigate off-target events and immunogenicity. Here, we review major advances in novel delivery platforms based on cell-derived vesicles - extracellular vesicles and virus-like particles - for transient delivery of gene editing payloads. We discuss major findings regarding packaging, in vivo biodistribution, therapeutic efficacy, and safety concerns of cell-derived vesicles delivery of gene editing cargos and their potential for clinical translation.

Beyond Traditional Medicine: EVs-Loaded Hydrogels as a Game Changer in Disease Therapeutics

Extracellular vesicles (EVs), especially exosomes, have shown great therapeutic potential in the treatment of diseases, as they can target cells or tissues. However, the therapeutic effect of EVs is limited due to the susceptibility of EVs to immune system clearance during transport in vivo. Hydrogels have become an ideal delivery platform for EVs due to their good biocompatibility and porous structure. This article reviews the preparation and application of EVs-loaded hydrogels as a cell-free therapy strategy in the treatment of diseases. The article also discusses the challenges and future outlook of EVs-loaded hydrogels.

Preconditioning of exosomes derived from human olfactory ensheathing cells improved motor coordination and balance in an SCA3/MJD mouse model: A new therapeutic approach

Exosome therapy is a novel trend in regeneration medicine. However, identifying a suitable biomarker that can associate the therapeutic efficacy of exosomes with SCA3/MJD is essential. In this study, parental cells were preconditioned with butylidenephthalide (Bdph) for exosome preparation to evaluate the therapeutic effect of SCA3/MJD. The therapeutic agent hsa-miRNA-6780-5p was enriched up to 98-fold in exosomes derived from butylidenephthalide (Bdph)-preconditioned human olfactory ensheathing cells (hOECs) compared with that in naïve hOECs exosomes. The particle sizes of exosomes derived from naïve hOECs and those derived from hOECs preconditioned with Bdph were approximately 113.0 ± 3.5 nm and 128.9 ± 0.7 nm, respectively. A liposome system was used to demonstrate the role of hsa-miRNA-6780-5p, wherein hsa-miRNA-6780-5p was found to enhance autophagy and inhibit the expression of spinocerebellar ataxia type 3 (SCA3) disease proteins with the polyglutamine (polyQ) tract. Exosomes with enriched hsa-miRNA-6780-5p were further applied to HEK-293-84Q cells, leading to decreased expression of polyQ and increased autophagy. The results were reversed when 3MA, an autophagy inhibitor, was added to the cells treated with hsa-miRNA-6780-5p-enriched exosomes, indicating that the decreased polyQ expression was modulated via autophagy. SCA3 mice showed improved motor coordination behavior when they intracranially received exosomes enriched with hsa-miRNA-6780-5p. SCA3 mouse cerebellar tissues treated with hsa-miRNA-6780-5p-enriched exosomes showed decreased expression of polyQ and increased expression of LC3II/I, an autophagy marker. In conclusion, our findings can serve as a basis for developing an alternative therapeutic strategy for SCA3 disease treatment using miRNA-enriched exosomes derived from chemically preconditioned cells.