Bone morphogenetic protein-7 release from endogenous neural precursor cells suppresses the tumourigenicity of stem-like glioblastoma cells

Glioblastoma cells with stem-like properties control brain tumour growth and recurrence. Here, we show that endogenous neural precursor cells perform an anti-tumour response by specifically targeting stem-like brain tumour cells. In vitro, neural precursor cells predominantly express bone morphogenetic protein-7; bone morphogenetic protein-7 is constitutively released from neurospheres and induces canonical bone morphogenetic protein signalling in stem-like glioblastoma cells. Exposure of human and murine stem-like brain tumour cells to neurosphere-derived bone morphogenetic protein-7 induces tumour stem cell differentiation, attenuates stem-like marker expression and reduces self-renewal and the ability for tumour initiation. Neurosphere-derived or recombinant bone morphogenetic protein-7 reduces glioblastoma expansion from stem-like cells by down-regulating the transcription factor Olig2. In vivo, large numbers of bone morphogenetic protein-7-expressing neural precursors encircle brain tumours in young mice, induce canonical bone morphogenetic protein signalling in stem-like glioblastoma cells and can thereby attenuate tumour formation. This anti-tumour response is strongly reduced in older mice. Our results indicate that endogenous neural precursor cells protect the young brain from glioblastoma by releasing bone morphogenetic protein-7, which acts as a paracrine tumour suppressor that represses proliferation, self-renewal and tumour-initiation of stem-like glioblastoma cell

Current challenges and future directions for engineering extracellular vesicles for heart, lung, blood and sleep diseases.

Extracellular vesicles (EVs) carry diverse bioactive components including nucleic acids, proteins, lipids and metabolites that play versatile roles in intercellular and interorgan communication. The capability to modulate their stability, tissue-specific targeting and cargo render EVs as promising nanotherapeutics for treating heart, lung, blood and sleep (HLBS) diseases. However, current limitations in large-scale manufacturing of therapeutic-grade EVs, and knowledge gaps in EV biogenesis and heterogeneity pose significant challenges in their clinical application as diagnostics or therapeutics for HLBS diseases. To address these challenges, a strategic workshop with multidisciplinary experts in EV biology and U.S. Food and Drug Administration (USFDA) officials was convened by the National Heart, Lung and Blood Institute. The presentations and discussions were focused on summarizing the current state of science and technology for engineering therapeutic EVs for HLBS diseases, identifying critical knowledge gaps and regulatory challenges and suggesting potential solutions to promulgate translation of therapeutic EVs to the clinic. Benchmarks to meet the critical quality attributes set by the USFDA for other cell-based therapeutics were discussed. Development of novel strategies and approaches for scaling-up EV production and the quality control/quality analysis (QC/QA) of EV-based therapeutics were recognized as the necessary milestones for future investigations.Funding information: National Heart, Lung, and Blood Institute, Grant/Award Numbers: HL 122596, HL124021, HL124074, HL128297, HL141080, HL155346-01, R35HL150807, R56HL141206 Prithu Sundd was supported by NIH-NHLBI R01 grants (HL128297 and HL141080) and 18TPA34170588 from American Heart Association. Stephen Y. Chan was supported by NIH grants R01 HL124021 and HL 122596 as well as AHA grant 18EIA33900027. SuamyaDaswas supported by NIH grants R35HL150807, UH3 TR002878 andAHASFRN35120123. ZhenjiaWangwas supported by NIH grant (R01EB027078). Pilar Martín was supported by MCIN-ISCIII-Fondo de Investigación Sanitaria grant PI22/01759. KennethW.Witwer was supported in part by NIH grants R01AI144997, R01DA047807, R33MH118164 andUH3CA241694. Tianji Chen was supported by AHA Career Development Award 18CDA34110301, Gilead Sciences Research Scholars Program in PAH, NIH-NHLBI grant R56HL141206 and Chicago Biomedical ConsortiumCatalyst Award. EduardoMarbán was supported byNIH R01 HL124074 and HL155346-01.S

倫理創成研究の動向 : シュレーダー＝フレチェットの『リスクと合理性』から

Mechanisms behind how the immune system signals to the brain in response to systemic inflammation are not fully understood. Transgenic mice expressing Cre recombinase specifically in the hematopoietic lineage in a Cre reporter background display recombination and marker gene expression in Purkinje neurons. Here we show that reportergene expression in neurons is caused by intercellular transfer of functional Cre recombinase messenger RNA from immune cells into neurons in the absence of cell fusion. In vitro purified secreted extracellular vesicles (EVs) from blood cells contain Cre mRNA, which induces recombination in neurons when injected into the brain. Although Cre-mediated recombination events in the brain occur very rarely in healthy animals, their number increases considerably in different injury models, particularly under inflammatory conditions, and extend beyond Purkinje neurons to other neuronal populations in cortex, hippocampus, and substantia nigra. Recombined Purkinje neurons differ in their miRNA profile from their nonrecombined counterparts, indicating physiological significance. These observations reveal the existence of a previously unrecognized mechanism to communicate RNA-based signals between the hematopoietic system and various organs, including the brain, in response to inflammation

Obstacles and opportunities in the functional analysis of extracellular vesicle RNA - An ISEV position paper

The release of RNA-containing extracellular vesicles (EV) into the extracellular milieu has been demonstrated in a multitude of different in vitro cell systems and in a variety of body fluids. RNA-containing EV are in the limelight for their capacity to communicate genetically encoded messages to other cells, their suitability as candidate biomarkers for diseases, and their use as therapeutic agents. Although EV-RNA has attracted enormous interest from basic researchers, clinicians, and industry, we currently have limited knowledge on which mechanisms drive and regulate RNA incorporation into EV and on how RNAencoded messages affect signalling processes in EV-targeted cells. Moreover, EV-RNA research faces various technical challenges, such as standardisation of EV isolationmethods, optimisation of methodologies to isolate and characteriseminute quantities of RNA found in EV, and development of approaches to demonstrate functional transfer of EV-RNA in vivo. These topics were discussed at the 2015 EV-RNA workshop of the International Society for Extracellular Vesicles. This position paper was written by the participants of the workshop not only to give an overview of the current state of knowledge in the field, but also to clarify that our incomplete knowledge – of the nature of EV(-RNA)s and of how to effectively and reliably study them – currently prohibits the implementation of gold standards in EV-RNA research. In addition, this paper creates awareness of possibilities and limitations of currently used strategies to investigate EV-RNA and calls for caution in interpretation of the obtained data

Neural stem cells and their contribution to neurogenesis in the adult mammalian brain

For a long time it was believed that neurogenesis in the mammalian central nervous system was restricted to the embryonic and early postnatal period. Almost four decades ago Altman and colleagues challenged this notion, but it took more than thirty years before new studies with refined methods convincingly demonstrated neurogenesis in the adult mammalian brain, including the adult monkey and human brain. Another major discovery was the demonstration by Reynolds and Weiss (1992) that neural stem cells persist in the mature brain that could be grown in culture and had the hallmark properties of stem cells: multipotency and self-renewal capacity. An obvious question following the discovery of stem cells in the adult brain was the localization and identity of these cells. We tested the hypothesis if ependymal cells, which delineate the ventricular system, might be a neural stem cell population in the adult brain. Ependymal cells were labeled in vivo, using either the fluoroescent label DiI or an adenovirus expressing the reporter gene lacZ. Immediately following an intraventricular injection, labeling was restricted to ependymal cells. At later timepoints labeled cells could be observed to enter the migratory stream to the olfactory bulb. There they differentiated into neurons as demonstrated by double labeling with neuronal markers. Based on fluorescent labeling and on their specific morphology single ependymal cells could be isolated, cultured and induced to differentiate into the major cell types of the CNS. Exploiting the fact that ependymal cells express the notch- I receptor on their surface, neural stem cells could be enriched by magnetic sorting. Long term labeling of cells in the subventricular zone and the spinal cord with BrdU revealed that neural stem cells are slowly dividing. After a traumatic injury to the spinal cord however, proliferation of ependymal cells increased. Newborn cells migrated from the central canal to the site of injury where they contributed to the formation of the glial scar. A very slow rate of proliferation can be indicative for a stem cell in certain tissues and is widely considered as a primary step leading towards their identification. We devised a method that combined postembedding, detection and ultrastructural characterization of immunogold labeled cells, thus allowing for the relatively rapid screening of rarely dividing cells in the adult central nervous system. This technique was applied to identify the ultrastructure of slowly proliferating putative stern cells in the adult mouse spinal cord. A specific supplement added to the culture medium was shown to have a selective effect on the propagation of distinct neural stem cell populations, This was in contrast to hypoxic culture conditions which were shown not to have this specific effect on neural stem cell propagation. There were no apparent differences between the distinct neural stem cell populations in their morphology, capacity for self-renewal, or ability to differentiate into glia and neurons. Intraventricular infusion of EphB2 receptor leads to a cellular rearrangement in the subventricular zone with astrocytes contacting the ventricular lumen. After infusing EphB2 receptors or vehicle solution, an upregulation of GFAP expression in ependymal cells was seen in both cases. We conclude that this is an injury related reaction rather than a specific effect of EphB2. The adult mammalian hippocampus and olfactory bulb are structures with an extensive, continuous generation of interneurons derived from stem cells. We asked whether there may also be a turnover of neurons in other regions of the adult brain, and focused on the substantia nigra pars compacta in the midbrain, where the dopamine- producing neurons that are lost in Parkinson's disease reside. We found that despite ongoing neuronal cell death in the substantia nigra, total cell number remained constant over a large part of the life span of the adult mouse. This indicated that there must be the generation of new neurons to compensate for cell loss. After long term labeling with either BrdU or DiI, we found TH-positive neurons with BrdU positive nuclei or DiI labeled membranes were found. We obtained similar results after labeling with tritiated thymidine followed by autoradiography. As the most likely origin for newborn dopaminergic neurons, we identified ependymal cells lining the third ventricular recess and the cerebral aqueduct by labeling with BrdU or DiI. Newborn neurons were found to send projections to their target area and integrate into the local synaptic circuitry as assessed by retrograde tracing and pseudorabies virus labeling studies. Similar to other injury studies, we could show that the rate of neurogenesis is increased after selectively ablating dopaminergic neurons with the toxin MPTP

Developments in new biotechnology firms in Germany.

Germany now has a substantial number of new biotechnology firms, with the number steadily increasing. The institutional framework has been slow to develop for this novel form of company, but many are now emerging and will certainly play an important part in the dynamics of the system. At the same time, the science base in this area has gained considerably in breadth and quality. The essential questions that arise from these recent developments are: (i) what prevented these new biotechnology firms from growing earlier and what is the current situation? (ii) What changes have occurred which have stimulated this growth? (iii) How are biotechnology companies going to develop further and what are the implications for Germany's pharmaceutical industry and wider economy? A database for biotechnology firms in Germany was set up of which a subset was used to analyse the current state of development. The following conclusions were reached: (i) Germany now has a substantial number of new biotechnology firms and the numbers are steadily increasing. (ii) Their collaborations with and proximity to academic centres of excellence suggests they are well embedded in the German research system. However, their sectoral composition sets them apart from their American counterparts, with greater bias towards instrumentation and environmental biotechnology, both areas of German industrial strength. (iii) Since the mid-1980s there has been continuous, if slow, adaptation to the institutional framework supporting biotechnology. These changes have finally resulted in an effective network of industry, academic and government links and have helped to promote both an increasingly strong scientific performance and the development of new firms. The authors suggest that, although these developments do not conform to the Anglo-Saxon entrepreneurial model in which new firms effectively forge new industries, the German evolutionary approach to innovation may still be holding its ground