Recipient Cells Research Articles

Novel JAK Inhibitors to Reduce Graft-Versus-Host Disease after Allogeneic Hematopoietic Cell Transplantation in a Preclinical Mouse Model.

Allogeneic hematopoietic cell transplantation (allo-HCT) is a highly effective, well-established treatment for patients with various hematologic malignancies and non-malignant diseases. The therapeutic benefits of allo-HCT are mediated by alloreactive T cells in donor grafts. However, there is a significant risk of graft-versus-host disease (GvHD), in which the donor T cells recognize recipient cells as foreign and attack healthy organs in addition to malignancies. We previously demonstrated that targeting JAK1/JAK2, mediators of interferon-gamma receptor (IFNGR) and IL-6 receptor signaling, in donor T cells using baricitinib and ruxolitinib results in a significant reduction in GvHD after allo-HCT. Furthermore, we showed that balanced inhibition of JAK1/JAK2 while sparing JAK3 is important for the optimal prevention of GvHD. Thus, we have generated novel JAK1/JAK2 inhibitors, termed WU derivatives, by modifying baricitinib. Our results show that WU derivatives have the potential to mitigate GvHD by upregulating regulatory T cells and immune reconstitution while reducing the frequencies of antigen-presenting cells (APCs) and CD80 expression on these APCs in our preclinical mouse model of allo-HCT. In addition, WU derivatives effectively downregulated CXCR3 and T-bet in primary murine T cells. In summary, we have generated novel JAK inhibitors that could serve as alternatives to baricitinib or ruxolitinib.

Targeted delivery of MerTK protein via cell membrane engineered nanoparticle enhances efferocytosis and attenuates atherosclerosis in diabetic ApoE−/− Mice

BackgroundClearance of apoptotic cells by efferocytosis is crucial for prevention of atherosclerosis progress, and impaired efferocytosis contributes to the aggravated atherosclerosis.ResultsIn this study, we found that diabetic ApoE–/– mice showed aggravated atherosclerosis as hyperglycemia damaged the efferocytosis capacity at least partially due to decreased expression of Mer tyrosine kinase (MerTK) on macrophages. To locally restore MerTK in the macrophages in the plaque, hybrid membrane nanovesicles (HMNVs) were thus developed. Briefly, cell membrane from MerTK overexpressing RAW264.7 cell and transferrin receptor (TfR) overexpressing HEK293T cell were mixed with DOPE polymers to produce nanovesicles designated as HMNVs. HMNVs could fuse with the recipient cell membrane and thus increased MerTK in diabetic macrophages, which in turn restored the efferocytosis capacity. Upon intravenous administration into diabetic ApoE–/– mice, superparamagnetic iron oxide nanoparticles (SMN) decorated HMNVs accumulated at the aorta site significantly under magnetic navigation, where the recipient macrophages cleared the apoptotic cells efficiently and thus decreased the inflammation.Conclusions Our study indicates that MerTK decrease in macrophages contributes to the aggravated atherosclerosis in diabetic ApoE–/– mice and regional restoration of MerTK in macrophages of the plaque via HMNVs could be a promising therapeutic approach.Graphic

Chromosome Transplantation: Opportunities and Limitations.

There are thousands of rare genetic diseases that could be treated with classical gene therapy strategies such as the addition of the defective gene via viral or non-viral delivery or by direct gene editing. However, several genetic defects are too complex for these approaches. These "genomic mutations" include aneuploidies, intra and inter chromosomal rearrangements, large deletions, or inversion and copy number variations. Chromosome transplantation (CT) refers to the precise substitution of an endogenous chromosome with an exogenous one. By the addition of an exogenous chromosome and the concomitant elimination of the endogenous one, every genetic defect, irrespective of its nature, could be resolved. In the current review, we analyze the state of the art of this technique and discuss its possible application to human pathology. CT might not be limited to the treatment of human diseases. By working on sex chromosomes, we showed that female cells can be obtained from male cells, since chromosome-transplanted cells can lose either sex chromosome, giving rise to 46,XY or 46,XX diploid cells, a modification that could be exploited to obtain female gametes from male cells. Moreover, CT could be used in veterinary biology, since entire chromosomes containing an advantageous locus could be transferred to animals of zootechnical interest without altering their specific genetic background and the need for long and complex interbreeding. CT could also be useful to rescue extinct species if only male cells were available. Finally, the generation of "synthetic" cells could be achieved by repeated CT into a recipient cell. CT is an additional tool for genetic modification of mammalian cells.

Single-Cell RNA Sequencing in Organ and Cell Transplantation.

Single-cell RNA sequencing is a high-throughput novel method that provides transcriptional profiling of individual cells within biological samples. This method typically uses microfluidics systems to uncover the complex intercellular communication networks and biological pathways buried within highly heterogeneous cell populations in tissues. One important application of this technology sits in the fields of organ and stem cell transplantation, where complications such as graft rejection and other post-transplantation life-threatening issues may occur. In this review, we first focus on research in which single-cell RNA sequencing is used to study the transcriptional profile of transplanted tissues. This technology enables the analysis of the donor and recipient cells and identifies cell types and states associated with transplant complications and pathologies. We also review the use of single-cell RNA sequencing in stem cell implantation. This method enables studying the heterogeneity of normal and pathological stem cells and the heterogeneity in cell populations. With their remarkably rapid pace, the single-cell RNA sequencing methodologies will potentially result in breakthroughs in clinical transplantation in the coming years.

Defining tropism and activity of natural and engineered extracellular vesicles.

Extracellular vesicles (EVs) have important roles as mediators of cell-to-cell communication, with physiological functions demonstrated in various in vivo models. Despite advances in our understanding of the biological function of EVs and their potential for use as therapeutics, there are limitations to the clinical approaches for which EVs would be effective. A primary determinant of the biodistribution of EVs is the profile of proteins and other factors on the surface of EVs that define the tropism of EVs in vivo. For example, proteins displayed on the surface of EVs can vary in composition by cell source of the EVs and the microenvironment into which EVs are delivered. In addition, interactions between EVs and recipient cells that determine uptake and endosomal escape in recipient cells affect overall systemic biodistribution. In this review, we discuss the contribution of the EV donor cell and the role of the microenvironment in determining EV tropism and thereby determining the uptake and biological activity of EVs.

Applications of Exosomal miRNAs from Mesenchymal Stem Cells as Skin Boosters.

The skin is the outer layer of the human body, and it is crucial in defending against injuries and damage. The regenerative capacity of aging and damaged skin caused by exposure to external stimuli is significantly impaired. Currently, the rise in average life expectancy and the modern population's aesthetic standards have sparked a desire for stem-cell-based therapies that can address skin health conditions. In recent years, mesenchymal stem cells (MSCs) as therapeutic agents have provided a promising and effective alternative for managing skin regeneration and rejuvenation, attributing to their healing capacities that can be applied to damaged and aged skin. However, it has been established that the therapeutic effects of MSC may be primarily mediated by paracrine mechanisms, particularly the release of exosomes (Exos). Exosomes are nanoscale extracellular vesicles (EVs) that have lipid bilayer and membrane structures and can be naturally released by different types of cells. They influence the physiological and pathological processes of recipient cells by transferring a variety of bioactive molecules, including lipids, proteins, and nucleic acids such as messenger RNAs (mRNAs) and microRNAs (miRNAs) between cells, thus playing an important role in intercellular communication and activating signaling pathways in target cells. Among them, miRNAs, a type of endogenous regulatory non-coding RNA, are often incorporated into exosomes as important signaling molecules regulating protein biosynthesis. Emerging evidence suggests that exosomal miRNAs from MSC play a key role in skin regeneration and rejuvenation by targeting multiple genes and regulating various biological processes, such as participating in inflammatory responses, cell migration, proliferation, and apoptosis. In this review, we summarize the recent studies and observations on how MSC-derived exosomal miRNAs contribute to the regeneration and rejuvenation of skin tissue, with particular attention to the applications of bioengineering methods for manipulating the miRNA content of exosome cargo to improve their therapeutic potential. This review can provide new clues for the diagnosis and treatment of skin damage and aging, as well as assist investigators in exploring innovative therapeutic strategies for treating a multitude of skin problems with the aim of delaying skin aging, promoting skin regeneration, and maintaining healthy skin.

Potential of Exosomes as Therapeutics and Therapy Targets in Cancer Patients

After an initial positive response to chemotherapy, cancer patients often acquire chemoresistance and tumor relapse, which makes cancer one of the most lethal diseases worldwide. Exosomes are essential mediators of cell-to-cell communication by delivering their cargo, such as proteins, RNAs and DNA, from cell to cell. They participate in cancer progression, metastasis, immune response and therapy resistance. Their ability to shuttle between cells makes them efficient drug delivery systems. As drug transporters, they provide novel strategies for cancer therapy by advancing targeted drug therapy and improving the therapeutic effects of anti-cancer medications. In this review, a comprehensive overview of the potential of exosomes as therapeutic agents and targeted molecules in the treatment of cancer patients is given. The current challenges of preparation of exosomes loaded with drugs and delivering them to the recipient tumor cells as well as a consequent exosome-mediated cancer therapy are also discussed.

Engineered and Mimicked Extracellular Nanovesicles for Therapeutic Delivery.

Exosomes are spherical extracellular nanovesicles with an endosomal origin and unilamellar lipid-bilayer structure with sizes ranging from 30 to 100 nm. They contain a large range of proteins, lipids, and nucleic acid species, depending on the state and origin of the extracellular vesicle (EV)-secreting cell. EVs' function is to encapsulate part of the EV-producing cell content, to transport it through biological fluids to a targeted recipient, and to deliver their cargos specifically within the aimed recipient cells. Therefore, exosomes are considered to be potential biological drug-delivery systems that can stably deliver their cargo into targeted cells. Various cell-derived exosomes are produced for medical issues, but their use for therapeutic purposes still faces several problems. Some of these difficulties can be avoided by resorting to hemisynthetic approaches. We highlight here the uses of alternative exosome-mimes involving cell-membrane coatings on artificial nanocarriers or the hybridization between exosomes and liposomes. We also detail the drug-loading strategies deployed to make them drug-carrier systems and summarize the ongoing clinical trials involving exosomes or exosome-like structures. Finally, we summarize the open questions before considering exosome-like disposals for confident therapeutic delivery.

Abstract CT143: IFN-γ and donor leukocyte infusion to treat relapsed myeloblastic malignancies after allogeneic hematopoietic stem cell transplantation

Abstract Introduction: Allogeneic stem cell transplantation (alloSCT) can provide a cure for myeloid malignancies partially through the graft-vs-leukemia effect (GVL), wherein donor-derived alloreactive T cells attack recipient leukemia cells. Preclinical data strongly suggested IFN-γ is crucial for effective GVL against myeloblastic leukemia. IFN-γ receptor gene-deficient myeloblastic leukemia were resistant to GVL in mouse models (Matte-Martone, Shlomchik JCI 2017). IFN-γ upregulated HLA expression in relapsed myeloblasts in vitro (Christopher NEJM 2018, Toffalori Nat Med 2019). We hypothesized that IFN-γ would sensitize myeloblasts to alloreactive T cells and promote GVL. Here, we present the results of a phase 1 study to evaluate the safety of IFN-γ combined with donor leukocyte infusions (DLI) for relapsed myeloblastic malignancies post-transplant (NCT04628338). Methods: HLA-matched donor alloSCT recipients with relapsed acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS) and no active graft-versus-host disease (GVHD) were eligible. Patients self-administered 100mcg IFN-γ (Actimmune, Horizon Therapeutics) three times a week for 4 weeks (cohort 1) or 1 week (cohort 2), followed by DLI and concurrent IFN-γ for a total of 12 weeks. Flow cytometry-based surface HLA expression and single-cell RNAseq (scRNAseq) were analyzed using bone marrow (BM) collected before and after IFN-γ. Results: Seven patients with high-risk diseases (2 MDS and 5 AML) were enrolled. There were no serious adverse events during IFN-γ monotherapy. After DLI, 5 patients developed grade I-II GVHD along with immune effector cell-associated neurotoxicity syndrome (grade 1 or 2; n=2) and idiopathic pneumonia syndrome (IPS; n=1). All immune-mediated toxicities, including IPS, resolved with corticosteroids. 4 out of 6 DLI recipients achieved minimal residual disease negative complete remissions and full donor hematopoietic cell reconstitution. The median overall survival was 579 days (range, 97-906) in responders. Myeloid blasts upregulated HLA-DR after IFN-γ, and enrichment of recipient malignant hematopoietic stem cells expressing CIITA was observed in post-IFN-γ BM by scRNAseq. Conclusions: This first in human use of IFN-γ to treat post-transplant relapse was safe, with a promising efficacy signal when combined with DLI. Correlative studies support our hypothesis that in vivo IFN-γ activates myeloblasts, manifest by HLA-DR upregulation and CIITA induction. We plan to design a phase 2 trial to formally test the efficacy of this novel immunotherapeutic approach to boost GVL in alloSCT. Citation Format: Sawa Ito, Emily Geramita, Kedwin Ventura, Biswas Neupane, Shruti Bhise, Scott N. Furlan, Warren D. Shromchik. IFN-γ and donor leukocyte infusion to treat relapsed myeloblastic malignancies after allogeneic hematopoietic stem cell transplantation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT143.

Extracellular Microvesicles Modified with Arginine-Rich Peptides for Active Macropinocytosis Induction and Delivery of Therapeutic Molecules.

Extracellular vesicles (EVs), including exosomes and microvesicles (MVs), transfer bioactive molecules from donor to recipient cells in various pathophysiological settings, thereby mediating intercellular communication. Despite their significant roles in extracellular signaling, the cellular uptake mechanisms of different EV subpopulations remain unknown. In particular, plasma membrane-derived MVs are larger vesicles (100 nm to 1 μm in diameter) and may serve as efficient molecular delivery systems due to their large capacity; however, because of size limitations, receptor-mediated endocytosis is considered an inefficient means for cellular MV uptake. This study demonstrated that macropinocytosis (lamellipodia formation and plasma membrane ruffling, causing the engulfment of large fluid volumes outside cells) can enhance cellular MV uptake. We developed experimental techniques to induce macropinocytosis-mediated MV uptake by modifying MV membranes with arginine-rich cell-penetrating peptides for the intracellular delivery of therapeutic molecules.

Microdroplets Encapsulated with NFATc1-siRNA and Exosomes-Derived from MSCs Onto 3D Porous PLA Scaffold for Regulating Osteoclastogenesis and Promoting Osteogenesis.

Osteoporotic-related fractures remains a significant public health concern, thus imposing substantial burdens on our society. Excessive activation of osteoclastic activity is one of the main contributing factors for osteoporosis-related fractures. While polylactic acid (PLA) is frequently employed as a biodegradable scaffold in tissue engineering, it lacks sufficient biological activity. Microdroplets (MDs) have been explored as an ultrasound-responsive drug delivery method, and mesenchymal stem cell (MSC)-derived exosomes have shown therapeutic effects in diverse preclinical investigations. Thus, this study aimed to develop a novel bioactive hybrid PLA scaffold by integrating MDs-NFATc1-silencing siRNA to target osteoclast formation and MSCs-exosomes (MSC-Exo) to influence osteogenic differentiation (MDs-NFATc1/PLA-Exo). Human bone marrow-derived mesenchymal stromal cells (hBMSCs) were used for exosome isolation. Transmission electron microscopy (TEM) and confocal laser scanning microscopy were used for exosome and MDs morphological characterization, respectively. The MDs-NFATc1/PLA-Exo scaffold was fabricated through poly(dopamine) and fibrin gel coating. Biocompatibility was assessed using RAW 264.7 macrophages and hBMSCs. Osteoclast formations were examined via TRAP staining. Osteogenic differentiation of hBMSCs and cytokine expression modulation were also investigated. MSC-Exo exhibited a cup-shaped structure and effective internalization into cells, while MDs displayed a spherical morphology with a well-defined core-shell structure. Following ultrasound stimulation, the internalization study demonstrated efficient delivery of bioactive MDs into recipient cells. Biocompatibility studies indicated no cytotoxicity of MDs-NFATc1/PLA-Exo scaffolds in RAW 264.7 macrophages and hBMSCs. Both MDs-NFATc1/PLA and MDs-NFATc1/PLA-Exo treatments significantly reduced osteoclast differentiation and formation. In addition, our results further indicated MDs-NFATc1/PLA-Exo scaffold significantly enhanced osteogenic differentiation of hBMSCs and modulated cytokine expression. These findings suggest that the bioactive MDs-NFATc1/PLA-Exo scaffold holds promise as an innovative structure for bone tissue regeneration. By specifically targeting osteoclast formation and promoting osteogenic differentiation, this hybrid scaffold may address key challenges in osteoporosis-related fractures.

EV-COMM: A database of interspecies and intercellular interactions mediated by extracellular vesicles.

Intra- and inter-organismal interactions play a crucial role inthe maintenance and function of individuals, as well as communities. Extracellular vesicles (EVs) have been identified as effective mediators for the communication both within and between species. They can carry and transport molecular cargoes to transmit biological messages. Several databases (ExoBCD, ExoCarta, EVpedia, EV-TRACK, Vesiclepedia) complied the cargoes information including DNA, RNA, protein, lipid and metabolite associated with EVs. Databases that refer to the complete records on both donor and recipient information are warranted to facilitate the understanding of the interaction across cells and species. In this study, we developed a database that compiled the records equipped with a structured process of EV-mediated interaction. The sources of donor and recipient were classified by cell type, tissues/organs and species, thus providing an extended knowledge of cell-cell, species-species interaction. The isolation and identification methods were presented for assessing the quality of EVs. Information on functional cargoes was included, where microRNA was linked to a prediction server to broaden its potential effects. Physiological and pathological context was marked to show the environment where EVs functioned. At present, a total of 1481 data records in our database, including 971 cell-cell interactions belonging to more than 40 different tissues/organs, and 510 cross-species records. The database provides a web interface to browse, search, visualize and download the interaction records. Users can search for interactions by selecting the context of interest or specific cells/species types, as well as functional cargoes. To the best of our knowledge, the database is the first comprehensive database focusing on interactions between donor and recipient cells or species mediated by EVs, serving as a convenient tool to explore and validate interactions. The Database, shorten as EV-COMM (EV mediated communication) is freely available at http://sdc.iue.ac.cn/evs/list/ and will be continuously updated.

(602) - Gene Expression Analysis of B and T Cells in De Novo mTOR Inhibitor Recipients Over Time

(602) - Gene Expression Analysis of B and T Cells in De Novo mTOR Inhibitor Recipients Over Time

(685) - Development of an Easy-to-Use Flow Cytometric Panel for Monitoring B Regulatory Cells in Transplant Recipients

(685) - Development of an Easy-to-Use Flow Cytometric Panel for Monitoring B Regulatory Cells in Transplant Recipients

The Landscape of Exosomes Biogenesis to Clinical Applications.

Exosomes are extracellular vesicles that originate from various cells and mediate intercellular communication, altering the behavior or fate of recipient cells. They carry diverse macromolecules, such as lipids, proteins, carbohydrates, and nucleic acids. Environmental stressors can change the exosomal contents of many cells, making them useful for diagnosing many chronic disorders, especially neurodegenerative, cardiovascular, cancerous, and diabetic diseases. Moreover, exosomes can be engineered as therapeutic agents to modulate disease processes. State-of-art techniques are employed to separate exosomes including ultracentrifugation, size-exclusion chromatography and immunoaffinity. However, modern technologies such as aqueous two-phase system as well as microfluidics are gaining attention in the recent years. The article highlighted the composition, biogenesis, and implications of exosomes, as well as the standard and novel methods for isolating them and applying them as biomarkers and therapeutic cargo carriers.

The Difference of Milk-Derived Extracellular Vesicles from Cow Colostrum and Mature Milk on miRNAs Expression and Protecting Intestinal Epithelial Cells against Lipopolysaccharide Damage.

Intestinal epithelial cells (IECs) play crucial roles in forming an essential barrier, providing host defense against pathogens and regulating nutrients absorption. Milk-derived extracellular vesicles (EVs) within its miRNAs are capable of modulating the recipient cell function. However, the differences between colostrum and mature milk EVs and their biological function in attenuating intestinal epithelial cell injury remain poorly understood. Thus, we carried out the present study to characterize the difference between colostrum and mature milk-derived miRNA of EVs and the effect of colostrum and mature milk EVs on the proliferation, apoptosis, proinflammatory cytokines and intestinal epithelial barrier related genes in IEC-6 induced by LPS. Differential expression of 329 miRNAs was identified between colostrum and mature milk EVs, with 185 miRNAs being downregulated and 144 upregulated. In addition, colostrum contains a greater number and protein concentration of EVs than mature milk. Furthermore, compared to control, EVs derived from colostrum significantly inhibited the expression of apoptosis- (Bax, p53, and caspase-3) and proinflammatory-related genes (TNFα, IL6, and IL1β). EVs derived from mature milk did not affect expression of apoptosis-related genes (Bax, p53, bcl2, and caspase-3). The EVs derived from mature milk significantly inhibited the expression of proinflammatory-related genes (TNFα and IL6). Western blot analysis also indicated that colostrum and mature milk EVs significantly decreased the apoptosis of IEC-6 cells. The EdU assay results showed that colostrum and mature milk EVs significantly increased the proliferation of IEC-6 cells. The expression of intestinal barrier-related genes (TJP1, CLDN1, OCLN, CDX2, MUC2, and IGF1R) was significantly promoted in IEC-6 cells after colostrum and mature milk EVs addition. Importantly, colostrum and mature milk EVs significantly relieved the LPS-induced inhibition of proliferation and intestinal barrier-related genes expression and attenuated apoptosis and proinflammatory responses induced by LPS in IEC-6 cells. Flow cytometry and Western blot analysis also indicated that colostrum and mature milk EVs significantly affect the apoptosis of IEC-6 cells induced by LPS. The results also indicated that EVs derived from colostrum had better effects on inhibiting the apoptosis- and proinflammatory cytokines-related genes expression. However, the EVs derived from mature milk exhibited beneficial effects on intestinal epithelial barrier protection. The present study will provide a better understanding of the role of EVs derived from colostrum and milk in dairy cows with different responses in the regulation of intestinal cells function, and also presents new evidence for the change of EVs cargos during various stages of lactation.

Extracellular vesicles derived from human foreskin cells (hFS-Exo) accelerate cell migration and angiogenesis through MAPK pathway: an in vitro study.

Wound healing is one of the important processes in the body. Attempts to create new drugs are of interest due to the side effects of natural and chemical wound healing compounds. To overcome this obstacle, stem cells have been used as healing agents. However, both difficulties in collection and risks such as rejection and teratoma in the recipient body have limited the use of stem cells, directly. Since the potential content of the stem cells can be transferred to the recipient cells by vesicles, small extracellular vesicles have recently become prominent agents. The wound-healing effect of extracellular vesicles derived from foreskin cells was investigated in both keratinocyte and endothelial cells. Migration assay, RT-PCR, Col1a1 ELISA and Western Blot experiments were utilized to reveal healing effect of EVs and its possible molecular pathways. EV-treated groups exhibited more proliferative, invasive, and migrative characteristics. When comparing to the control group, new vessel formation was induced in EV groups. An increase in gene levels of growth factors related to wound healing and change in the mitogen-activated protein kinase (MAPK) signaling pathway proteins in EV-treated groups were determined. Possible molecular mechanisms underlying cell movements were associated with the MAPK pathway. It was found that human foreskin cell EVs (hFS-Exo) may have a potential to heal wounds in a short period of time by triggering the MAPK pathway. hFS-Exo could be a new promising wound healing agent in the future.

Optimal conditions for adenoviral transduction of immature dendritic cells without affecting the tolerogenic activity of DC-based immunotherapy

Dendritic cells (DCs) play a pivotal role in maintaining immune tolerance. Using recombinant adenovirus (rAd) to deliver vectors to immature dendritic cells (imDCs) is an important method for studying the tolerogenic function of DCs. We found that using RPMI medium and a higher MOI during transduction increased the expression of CD80, CD86, and MHC-II on the surface of imDCs. Our data reveal a significant increase in the secretion of the pro-inflammatory cytokine IL-6 in the group showing the most pronounced phenotypic changes. In the mouse heart transplant model, imDCs with unstable phenotype and function due to adenoviral transduction resulted in an increased proportion of Th1 and Th17 cells in recipients. However, these effects can be managed, and our proposed optimized transduction strategy significantly minimizes these adverse effects. Our study holds significant implications for the development and optimization of immunotherapy utilizing tolerogenic dendritic cells.

Dissemination of the Flavivirus Subgenomic Replicon Genome and Viral Proteins by Extracellular Vesicles.

Extracellular vesicles (EVs) such as exosomes have been shown to play physiological roles in cell-to-cell communication by delivering various proteins and nucleic acids. In addition, several studies revealed that the EVs derived from the cells that are infected with certain viruses could transfer the full-length viral genomes, resulting in EVs-mediated virus propagation. However, the possibility cannot be excluded that the prepared EVs were contaminated with infectious viral particles. In this study, the cells that harbor subgenomic replicon derived from the Japanese encephalitis virus and dengue virus without producing any replication-competent viruses were employed as the EV donor. It was demonstrated that the EVs in the culture supernatants of those cells were able to transfer the replicon genome to other cells of various types. It was also shown that the EVs were incorporated by the recipient cells primarily through macropinocytosis after interaction with CD33 and Tim-1/Tim-4 on HeLa and K562 cells, respectively. Since the methods used in this study are free from contamination with infectious viral particles, it is unequivocally indicated that the flavivirus genome can be transferred by EVs from cell to cell, suggesting that this pathway, in addition to the classical receptor-mediated infection, may play some roles in the viral propagation and pathogenesis.

Transfer and fates of damaged mitochondria: role in health and disease.

Intercellular communication is pivotal in mediating the transfer of mitochondria from donor to recipient cells. This process orchestrates various biological functions, including tissue repair, cell proliferation, differentiation and cancer invasion. Typically, dysfunctional and depolarized mitochondria are eliminated through intracellular or extracellular pathways. Nevertheless, increasing evidence suggests that intercellular transfer of damaged mitochondria is associated with the pathogenesis of diverse diseases. This review investigates the prevalent triggers of mitochondrial damage and the underlying mechanisms of mitochondrial transfer, and elucidates the role of directional mitochondrial transfer in both physiological and pathological contexts. Additionally, we propose potential previously unknown mechanisms mediating mitochondrial transfer and explore their prospective roles in disease prevention and therapy.