Nexus between extracellular vesicles, immunomodulation and tissue remodeling: for good or for bad?

Activation of Resolution Pathways to Prevent and Fight Chronic Inflammation: Lessons From Asthma and Inflammatory Bowel Disease

Formerly considered as a passive process, the resolution of acute inflammation is now recognized as an active host response, with a cascade of coordinated cellular and molecular events that promotes termination of the inflammatory response and initiates tissue repair and healing. In a state of immune fitness, the resolution of inflammation is contained in time and space enabling the restoration of tissue homeostasis. There is increasing evidence that poor and/or inappropriate resolution of inflammation participates in the pathogenesis of chronic inflammatory diseases, extending in time the actions of pro-inflammatory mechanisms, and responsible in the long run for excessive tissue damage and pathology. In this review, we will focus on how resolution can be the target for therapy in "Th1/Th17 cell-driven" immune diseases and "Th2 cell-driven" immune diseases, with inflammatory bowel diseases (IBD) and asthma, as relevant examples. We describe the main cells and mediators stimulating the resolution of inflammation and discuss how pharmacological and dietary interventions but also life style factors, physical and psychological conditions, might influence the resolution phase. A better understanding of the impact of endogenous and exogenous factors on the resolution of inflammation might open a whole area in the development of personalized therapies in non-resolving chronic inflammatory diseases.

Biomaterial-based delivery systems of nucleic acid for regenerative research and regenerative therapy

Regenerative medicine is a new and promising medical method aiming at treating patients with defective or dysfunctional tissues by maintaining or enhancing the biological activity of cells. The development of biomaterial-based technologies, such as cell scaffolds and carriers for drug delivery system, are highly required to promote the regenerative research and regenerative therapy. Nucleic acids are one of the most feasible factors to efficiently modify the biological activity of cells. The effective and stable delivery of nucleic acids into cells is highly required to succeed in the modification. Biomaterials-based non-viral carriers or biological carriers, like exosomes, play an important role in the efficient delivery of nucleic acids. This review introduces the examples of regenerative research and regenerative therapy based on the delivery of nucleic acids with biomaterials technologies and emphasizes their importance to accomplish regenerative medicine.

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Modifying the activity of cells is important for regenerative medicine.

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Various nucleic acids regulate gene expression to modify the activity of cells.

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Intracellular delivery system is vital to the nucleic acids-based modification.

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Biomaterials are useful for the intracellular delivery of nucleic acids.

Heterogeneity of microvesicles from cancer cell lines under inflammatory stimulation with TNF-α

Microvesicles (MVs) represent a subgroup of extracellular vesicles (EVs) emerging from various cells by blebbing of their outer membrane. Therefore, they share features such as membrane composition and antigenicity with their parental cells. Released by many immune and tumor cells, MVs act as intercellular messengers, account for horizontal gene transfer and can activate the coagulation system. With the aim to investigate their relevance for tumor cell biology, we characterized MVs released by human tumor cell lines of various origins in the absence or presence of TNF-α. After stimulation, we used the combination of low and high-speed centrifugation to enrich MVs from cell culture supernatants. We analyzed the presentation of phosphatidylserine (PS) and tissue factor (TF) activity on the cell surface and investigated their potency to induce tumor cell migration. In all tumor cell lines, TNF-α stimulation enhanced the release of MVs. While the expression of PS was universally increased, an elevated activity of procoagulant TF could be detected on MVs from lung, pancreatic, and colon carcinoma, but not from breast and ovarian cancer cell lines. Functionally, TNF-α stimulation significantly increased the potency of MVs to induce tumor cell migration. In conclusion, inflammatory conditions promote the release of MVs with increased procoagulant activity from tumor cell lines in vitro. PS-containing and TF-expressing MVs may account for systemic activation of the coagulation system as seen in cancer patients and, since they induce tumor cell migration, they may serve as biomarkers for tumor progression.

None of us is the same as all of us: resolving the heterogeneity of extracellular vesicles using single-vesicle, nanoscale characterization with resonance enhanced atomic force microscope infrared spectroscopy (AFM-IR)

Extracellular vesicles (EVs) are highly specialized, nanoscale messengers that deliver biological signals and in doing so mediate intercellular communication. Increasing evidence shows that within populations of EVs, important properties including morphology, membrane composition, and content vary substantially. This heterogeneity arises in response to the nature, state, and environmental conditions of the cell source. However, currently there are no effective approaches, which unequivocally discriminate differences between individual EVs, which critically hampers progress in this emerging scientific area. Measuring EV heterogeneity is paramount to our understanding of how EVs influence the physiological and pathological functions of their target cells. Moreover, understanding EV heterogeneity is essential for their application as diagnostics and therapeutics. We propose an innovative approach using resonance enhanced atomic force microscope infrared spectroscopy (AFM-IR) to identify the nanoscale structural composition of EVs, as demonstrated and validated using EVs derived from two types of placenta stem cells. The particular strength of this approach is that it is a label-free and ultra-high sensitivity technique that has the power to measure individual EV heterogeneity. New insights gained by this method into EV heterogeneity will have a profound impact not only on our basic understanding of EV biology but also on disease diagnostics and the emerging area of EV-therapies.

Non-coding RNAs in Mesenchymal Stem Cell-Derived Extracellular Vesicles: Deciphering Regulatory Roles in Stem Cell Potency, Inflammatory Resolve, and Tissue Regeneration

Extracellular vesicles (EVs) are heterogeneous populations of nano- and micro-sized vesicles secreted by various cell types. There is mounting evidence that EVs have widespread roles in transporting proteins, lipids, and nucleic acids between cells and serve as mediators of intercellular communication. EVs secreted from stem cells could function as paracrine factors, and appear to mimic and recapitulate several features of their secreting cells. EV-mediated transport of regulatory RNAs provides a novel source of trans-regulation between cells. As such, stem cells have evolved unique forms of paracrine mechanisms for recapitulating their potencies with specialized functions by transporting non-coding RNAs (ncRNAs) via EVs. This includes the dissemination of stem cell-derived EV-ncRNAs and their regulatory effects elicited in differentiation, self-renewal, pluripotency, and the induction of reparative programs. Here, we summarize and discuss the therapeutic effects of mesenchymal stem cell-derived EV-ncRNAs in the induction of intrinsic regenerative programs elicited through regulating several mechanisms. Among them, most noticeable are the EV-mediated enrichment of ncRNAs at the injury sites contributing the regulation of matrix remodeling, epithelial mesenchymal transitions, and attraction of fibroblasts. Additionally, we emphasize EV-mediated transmission of anti-inflammatory RNAs from stem cells to injury site that potentially orchestrate the resolution of the inflammatory responses and immune alleviation to better facilitate healing processes. Collectively, this knowledge indicates a high value and potential of EV-mediated RNA-based therapeutic approaches in regenerative medicine.

Extracellular vesicle-mediated transport of non-coding RNAs between stem cells and cancer cells: implications in tumor progression and therapeutic resistance

Recent years have witnessed intensive progress in studying extracellular vesicles (EVs), both for understanding their basic biology and contribution to variety of diseases, biomarker discovery, and their potential as gene delivery vectors and source of innovative therapies. As such, stem cell-derived EVs have contributed significant knowledge which led to the development of cell-free therapies in regenerative medicine. Although, the role of stem cell-derived EVs in maintaining stemness, differentiation and repairing tissue injuries is relatively well-understood; however, knowledge about the contribution of stem cell-derived EVs in cancer progression is just emerging. The aim of this review is, therefore, to discuss the recent developments in stem cell-derived EVs and tumor progression, placing a particular focus on non-coding RNA (ncRNA) mediated cancer progression and resistance against therapies. This includes the failure of normal hematopoiesis and the progression of myeloid neoplasms, enhanced capacity of cancer cells to proliferate and metastasize, and the conversion of normal cells into cancer cells, activation of angiogenic pathways and dormancy in cancer cells. These processes are shared by mesenchymal stem cells (MSCs), cancer stem like-cells and cancer cells in an intricate intratumoral network in order to create self-strengthening tumor niche. In this context, EV-ncRNAs serve as mediators to relay bystander effects of secreting cancer stem cells (CSCs) into recipient cells for priming a tumor permissive environment and relaying therapeutic resistance. Collectively, this knowledge will improve our understandings and approaches in finding new therapeutic targets in the context of CSCs, which could be benefited through engineering EVs for innovative therapies.

Extracellular Vesicles, Tunneling Nanotubes, and Cellular Interplay: Synergies and Missing Links

The process of intercellular communication seems to have been a highly conserved evolutionary process. Higher eukaryotes use several means of intercellular communication to address both the changing physiological demands of the body and to fight against diseases. In recent years, there has been an increasing interest in understanding how cell-derived nanovesicles, known as extracellular vesicles (EVs), can function as normal paracrine mediators of intercellular communication, but can also elicit disease progression and may be used for innovative therapies. Over the last decade, a large body of evidence has accumulated to show that cells use cytoplasmic extensions comprising open-ended channels called tunneling nanotubes (TNTs) to connect cells at a long distance and facilitate the exchange of cytoplasmic material. TNTs are a different means of communication to classical gap junctions or cell fusions; since they are characterized by long distance bridging that transfers cytoplasmic organelles and intracellular vesicles between cells and represent the process of heteroplasmy. The role of EVs in cell communication is relatively well-understood, but how TNTs fit into this process is just emerging. The aim of this review is to describe the relationship between TNTs and EVs, and to discuss the synergies between these two crucial processes in the context of normal cellular cross-talk, physiological roles, modulation of immune responses, development of diseases, and their combinatory effects in tissue repair. At the present time this review appears to be the first summary of the implications of the overlapping roles of TNTs and EVs. We believe that a better appreciation of these parallel processes will improve our understanding on how these nanoscale conduits can be utilized as novel tools for targeted therapies.