Extracellular Vesicles within the Bone Marrow Niche : A novel way of communication between osteoblasts and hematopoietic progenitor cells

Cell-to-cell communication plays an essential role in regulating homeostasis in multicellular organisms. Recent evidence indicates that cells effectively communicate via extracellular vesicles (EVs), which carry bioactive cargo, such as proteins, lipids and RNA, between cells. Advancement in the field produced tremendous information that gives insights into the biological role of EVs in many aspects of physiological and pathophysiological events. Due to their signature content and biocompatibility, EVs represent a potential source of diagnostic tools and therapeutic agents. As well, their use might overcome limitations and risks associated with cell-therapy approaches. Bone is a complex organ consisting of a broad variety of cell types living in harmony within the favorable microenvironment of the bone marrow. The establishment of a proper communication network is key to ensure not only normal bone development but also many other vital

Molecular characterization of human osteoblast-derived extracellular vesicle mRNA using next-generation sequencing

Extracellular vesicles (EVs) are membrane-bound intercellular communication vehicles that transport proteins, lipids and nucleic acids with regulatory capacity between cells. RNA profiling using microarrays and sequencing technologies has revolutionized the discovery of EV-RNA content, which is crucial to understand the molecular mechanism of EV function. Recent studies have indicated that EVs are enriched with specific RNAs compared to the originating cells suggestive of an active sorting mechanism. Here, we present the comparative transcriptome analysis of human osteoblasts and their corresponding EVs using next-generation sequencing. We demonstrate that osteoblast-EVs are specifically depleted of cellular mRNAs that encode proteins involved in basic cellular activities, such as cytoskeletal functions, cell survival and apoptosis. In contrast, EVs are significantly enriched with 254 mRNAs that are associated with protein translation and RNA processing. Moreover, mRNAs enriched in EVs encode proteins important for communication with the neighboring cells, in particular with osteoclasts, adipocytes and hematopoietic stem cells. These findings provide the foundation for understanding the molecular mechanism and function of EV-mediated interactions between osteoblasts and the surrounding bone microenvironment

Osteoblasts secrete miRNA-containing extracellular vesicles that enhance expansion of human umbilical cord blood cells

Osteolineage cells represent one of the critical bone marrow niche components that support maintenance of hematopoietic stem and progenitor cells (HSPCs). Recent studies demonstrate that extracellular vesicles (EVs) regulate stem cell development via horizontal transfer of bioactive cargo, including microRNAs (miRNAs). Using next-generation sequencing we show that human osteoblast-derived EVs contain highly abundant miRNAs specifically enriched in EVs, including critical regulators of hematopoietic proliferation (e.g., miR-29a). EV treatment of human umbilical cord blood-derived CD34 + HSPCs alters the expression of candidate miRNA targets, such as HBP1, BCL2 and PTEN. Furthermore, EVs enhance proliferation of CD34 + cells and their immature subsets in growth factor-driven ex vivo expansion cultures. Importantly, EV-expanded cells retain their differentiation capacity in vitro and successfully engraft in vivo. These discoveries reveal a novel osteoblast-derived EV-mediated mechanism for regulation of HSPC proliferation and warrant consideration of EV-miRNAs for the development of expansion strategies to treat hematological disorders

Identification of osteolineage cell-derived extracellular vesicle cargo implicated in hematopoietic support

Osteolineage cell-derived extracellular vesicles (EVs) play a regulatory role in hematopoiesis and have been shown to promote the ex vivo expansion of human hematopoietic stem and progenitor cells (HSPCs). Here, we demonstrate that EVs from different human osteolineage sources do not have the same HSPC expansion promoting potential. Comparison of stimulatory and non-stimulatory osteolineage EVs by next-generation sequencing and mass spectrometry analyses revealed distinct microRNA and protein signatures identifying EV-derived candidate regulators of ex vivo HSPC expansion. Accordingly, the treatment of umbilical cord blood-derived CD34+ HSPCs with stimulatory EVs-altered HSPC transcriptome, including genes with known roles in cell proliferation. An integrative bioinformatics approach, which connects the HSPC gene expression data with the candidate cargo in stimulatory EVs, delineated the potentially targeted biological functions and pathways during hematopoietic cell expansion and development. In conclusion, our study giv

Minimal information for studies of extracellular vesicles 2018 (MISEV2018):a position statement of the International Society for Extracellular Vesicles and update of the MISEV2014 guidelines

The last decade has seen a sharp increase in the number of scientific publications describing physiological and pathological functions of extracellular vesicles (EVs), a collective term covering various subtypes of cell-released, membranous structures, called exosomes, microvesicles, microparticles, ectosomes, oncosomes, apoptotic bodies, and many other names. However, specific issues arise when working with these entities, whose size and amount often make them difficult to obtain as relatively pure preparations, and to characterize properly. The International Society for Extracellular Vesicles (ISEV) proposed Minimal Information for Studies of Extracellular Vesicles (“MISEV”) guidelines for the field in 2014. We now update these “MISEV2014” guidelines based on evolution of the collective knowledge in the last four years. An important point to consider is that ascribing a specific function to EVs in general, or to subtypes of EVs, requires reporting of specific information beyond mere description of function in a crude, potentially contaminated, and heterogeneous preparation. For example, claims that exosomes are endowed with exquisite and specific activities remain difficult to support experimentally, given our still limited knowledge of their specific molecular machineries of biogenesis and release, as compared with other biophysically similar EVs. The MISEV2018 guidelines include tables and outlines of suggested protocols and steps to follow to document specific EV-associated functional activities. Finally, a checklist is provided with summaries of key points

Кераміка «terra sigillata» з с. Зимне на Волині

Стаття присвячена публікації чотирьох керамічних посудин типу «terra sigillata», знайдених на дні р. Луги у с. Зимне Володимир-Волинського району Волинської області. Попередній аналіз цих знахідок дозволяє віднести їх до Понтійського центру виробництва такого посуду. Вірогідним шляхом потрапляння цієї колекції на Волинь була готська експансія у Північне Причорномор’я

Extracellular vesicles: Specialized bone messengers

Mammalian cells actively secrete factors that contribute to shape their microenvironment. These factors either travel freely or they are enclosed within the lipid bilayer of extracellular vesicles (EVs), and regulate the function of neighboring and distant cells. EVs are secreted by a wide spectrum of cell types and are found in various biological fluids. They convey their message by mediating the horizontal transfer of bioactive molecules, such as proteins, mRNAs and miRNAs, between cells. Recent studies showed the vital roles of EVs in a wide range of physiological and pathophysiological processes. In this review, we highlight the recent developments in the newly emerging EV field, including their biogenesis, molecular content and function. Moreover, we discuss the role of EVs in bone biology and their promising applications in diagnosis, drug development and regenerative therapy. (C) 2014 Published by Elsevier Inc