Clinical-grade multipotent adult progenitor cells durably control pathogenic T cell responses in human models of transplantation and autoimmunity.

A major goal of immunotherapy remains the control of pathogenic T cell responses that drive autoimmunity and allograft rejection. Adherent progenitor cells, including mesenchymal stromal cells (MSCs) and multipotent adult progenitor cells (MAPCs), represent attractive immunomodulatory cell therapy candidates currently active in clinical trials. MAPCs can be distinguished from MSCs on the basis of cellular phenotype, size, transcriptional profile, and expansion capacity. However, despite their ongoing evaluation in autoimmune and allogeneic solid organ transplantation settings, data supporting the immune regulatory potential of clinical-grade MAPCs are limited. In this study, we used allogeneic islet transplantation as a model indication to assess the ability of clinical-grade MAPCs to control T cell responses that drive immunopathology in human autoimmune disease and allograft rejection. MAPCs suppressed T cell proliferation and Th1 and Th17 cytokine production while increasing secretion of IL-10 and were able to suppress effector functions of bona fide autoreactive T cells from individuals with type 1 diabetes mellitus, including killing of human islets. Furthermore, MAPCs favored the proliferation of regulatory T cells during homeostatic expansion driven by γ-chain cytokines and exerted a durable, yet reversible, control of T cell function. MAPC suppression required licensing and proceeded via IDO-mediated tryptophan catabolism. Therefore, the common immune modulatory characteristics of clinical-grade MAPCs shown in this study suggest that they can be regarded as an alternative source of adult progenitor cells with similar clinical usefulness to MSCs. Taken collectively, these findings may guide the successful deployment of both MSCs and MAPCs for the amelioration of human autoimmunity and allograft rejection.

Engraftment, migration and differentiation of neural stem cells in the rat spinal cord following contusion injury.

BACKGROUND AIMS: Spinal cord injury is a devastating injury that impacts drastically on the victim's quality of life. Stem cells have been proposed as a therapeutic strategy. Neural stem (NS) cells have been harvested from embryonic mouse forebrain and cultured as adherent cells. These NS cells express markers of neurogenic radial glia. METHODS: Mouse NS cells expressing green fluorescent protein (GFP) were transplanted into immunosupressed rat spinal cords following moderate contusion injury at T9. Animals were left for 2 and 6 weeks then spinal cords were fixed, cryosectioned and analyzed. Stereologic methods were used to estimate the volume and cellular environment of the lesions. Engraftment, migration and differentiation of NS cells were also examined. RESULTS: NS cells integrated well into host tissue and appeared to migrate toward the lesion site. They expressed markers of neurons, astrocytes and oligodendrocytes at 2 weeks post-transplantation and markers of neurons and astrocytes at the 6-week time-point. NS cells appeared to have a similar morphologic phenotype to radial glia, in particular at the pial surface. CONCLUSIONS: Although no functional recovery was observed using the Basso Beattie Bresnahan (BBB) locomotor rating scale, NS cells are a potential cellular therapy for treatment of injured spinal cord. They may be used as delivery vehicles for therapeutic proteins because they show an ability to migrate toward the site of a lesion. They may also be used to replace lost or damaged neurons and oligodendrocytes.

A changing time: the International Society for Cellular Therapy embraces its industry members.

The last decade has seen a dramatic rise in the development of new cellular therapeutics in a wide range of indications. There have been acceptable safety profiles reported in early studies using blood-derived and adherent stem cell products, but also an inconsistent efficacy record. Further expansion has been hindered in part by a lack of capital (both private and public) and delayed entry into the cell therapy space by large healthcare and pharmaceutical companies, those members of the industry most reliably able to initiate and maintain advanced-phase clinical trials. With recognition that the International Society for Cellular Therapy (ISCT) is uniquely positioned to serve the global translational regenerative medicine research community as a network hub for scientific standards and policy, the ISCT commissioned the establishment of an Industry Task Force (ITF) to address current and future roles for industry. The objectives of the ITF were to gather information and prioritize efforts for a new Commercialization Committee (CC) and to construct innovative platforms that would foster constructive and synergistic collaborations between industry and ISCT. Recommendations and conclusions of the ITF included that the new CC: (1) foster new relationships with therapeutic and stem cell societies, (2) foster educational workshops and forums to cross-educate and standardize practices, (3) create industry subcommittees to address priority initiatives, with clear benchmarks and global implementation, and (4) establish a framework for a greater industry community within ISCT, opening doors for industry to share the new vision for commercialization of cell therapy, emphasizing the regenerative medicine space.

Deploying human pluripotent stem cells to treat central nervous system disorders: facts, challenges and realising the potential.

Human pluripotent stem cells (hPSC) represent a unique opportunity to study fundamental biological processes in a human- and cell-specific setting. Its translational potential and the impact on human health makes this technology revolutionary. The possibility to generate stem cells from almost any somatic cell, and their capacity to be differentiated in virtually all cells of the body has been demonstrated extensively during the last decade of research. Target-centric as well as phenotypic screenings using differentiated cells have become a reality, while the use of these cells for "disease modelling" is still challenging due to the paucity of relevant and reproducible phenotypes. The combination of hPSCs with gene editing technologies aiming to e.g. reduce immunogenic response has enabled promising clinical trials that will eventually demonstrate their therapeutic potential in tissue regeneration and cancer treatment. Maximizing the therapeutic applications of hPSCs requires systematic data comparison, consensus between scientists and health care professionals, as well as a close collaboration between research labs, clinics, and regulators. The goal of this review is to provide a comprehensive outlook of the current use of hPSCs in drug development and regenerative medicine for the treatment of central nervous system (CNS) disorders. In the first part, we analyse how hPSCs are currently used in drug development and discuss their use in challenging paradigms such as neurodegeneration. In the second part we review the status of hPSCs in regenerative medicine. Finally, key challenges and pitfalls of the technology will be discussed, and strategies proposed to improve hPSC research and to benefit patients across different therapeutic areas.

Hot Start to European Pluripotent Stem Cell Banking.

Achieving consistency in standards of access to and quality of human induced pluripotent stem cells has lagged behind their use. In Europe, a network of academic and industrial partners has been established to overcome this challenge. The experience reveals the devil in the detail of worthy ambitions informing future efforts.

Embryonic stem cells as a source of differentiated neural cells for pharmacological screens.

The process of bringing a new pharmacologically active drug to market is laborious, time consuming, and costly. From drug discovery to safety assessment, new methods are constantly sought to develop faster and more efficient procedures to eliminate drugs from further investigation because of their limited effectiveness or high toxicity. Because in vitro cell assays are an important arm of this discovery process, it is therefore somewhat unsurprising that there is an emerging contribution of embryonic stem (ES) cell technology to this area. This technology utilizes the in vitro differentiation of ES cells into somatic cell target populations that, when coupled to the use of "lineage selection" protocols, allows for the production of infinite numbers of pure populations of the desired cells for both bioactivity and toxicological screens. Unlike the use of transformed cell lines, ES-derived cells remain karyotypically normal and therefore better reflect the potential responses of cells in vivo, and when selected are more homogeneous than those obtained using primary cultures. In this chapter we discuss the use of ES cell-derived somatic cells in pharmacological screens, with particular emphasis on neural cells, and describe the methods and protocols associated with the development of ES cell-derived neural cell assays.

ES cell technology: an introduction to genetic manipulation, differentiation and therapeutic cloning.

ES cells are extraordinary cells, capable of proliferating in a pluripotent state indefinitely and of differentiating spontaneously into all cell types in vivo and many in vitro. However, the manipulation and modification of ES cells by processes such as directed differentiation and genetic modification have placed ES cells at the forefront of many biological studies and could lead to their application in biopharmaceutical areas such as cellular therapy and drug screening. Here we describe some of the ES cell based technologies that have lead to this realisation of ES cell potential.

Non-immortalized human neural stem (NS) cells as a scalable platform for cellular assays.

The utilization of neural stem cells and their progeny in applications such as disease modelling, drug screening or safety assessment will require the development of robust methods for consistent, high quality uniform cell production. Previously, we described the generation of adherent, homogeneous, non-immortalized mouse and human neural stem cells derived from both brain tissue and pluripotent embryonic stem cells (Conti et al., 2005; Sun et al., 2008). In this study, we report the isolation or derivation of stable neurogenic human NS (hNS) lines from different regions of the 8-9 gestational week fetal human central nervous system (CNS) using new serum-free media formulations including animal component-free conditions. We generated more than 20 adherent hNS lines from whole brain, cortex, lobe, midbrain, hindbrain and spinal cord. We also compared the adherent hNS to some aspects of the human CNS-stem cells grown as neurospheres (hCNS-SCns), which were derived from prospectively isolated CD133(+)CD24(-/lo) cells from 16 to 20 gestational week fetal brain. We found, by RT-PCR and Taqman low-density array, that some of the regionally isolated lines maintained their regional identity along the anteroposterior axis. These NS cells exhibit the signature marker profile of neurogenic radial glia and maintain neurogenic and multipotential differentiation ability after extensive long-term expansion. Similarly, hCNS-SC can be expanded either as neurospheres or in extended adherent monolayer with a morphology and marker expression profile consistent with radial glia NS cells. We demonstrate that these lines can be efficiently genetically modified with standard nucleofection protocols for both protein overexpression and siRNA knockdown of exogenously expressed and endogenous genes exemplified with GFP and Nestin. To investigate the functional maturation of neuronal progeny derived from hNS we (a) performed Agilent whole genome microarray gene expression analysis from cultures undergoing neuronal differentiation for up to 32 days and found increased expression over time for a number of drugable target genes including neurotransmitter receptors and ion channels and (b) conducted a neuropharmacology study utilizing Fura-2 Ca(2+) imaging which revealed a clear shift from an initial glial reaction to carbachol to mature neuron-specific responses to glutamate and potassium after prolonged neuronal differentiation. Fully automated culture and scale-up of select hNS was achieved; cells supplied by the robot maintained the molecular profile of multipotent NS cells and performed faithfully in neuronal differentiation experiments. Here, we present validation and utility of a human neural lineage-restricted stem cell-based assay platform, including scale-up and automation, genetic engineering and functional characterization of differentiated progeny.

Pharmacological potential of embryonic stem cells.

Established embryonic stem (ES) cell lines have been at the forefront of approaches to understand gene function during embryogenesis and in adult vertebrate organisms, principally due to exploitation of two essential attributes; their pluripotency or ability to contribute to all three germinal layers and germ line in mice and their ease of genetic modification. Endeavours to routinely establish ES cells from species other than mice have met with limited success, although with rapid progress being made in our understanding of their basic cell biology, the regular derivation of lines from pre-implantation embryos will become easier for many species including humans. With a recent growing awareness of how these cells can be made to grow in an unlimited, but regulated manner plus how their fate can be directed or manipulated into diverse, mature phenotypes in culture, it has become clear that the biological resource offers additional attractive features applicable for future biomedical research and therapy. Advanced mouse ES-based technologies are being used in the industry for pharmaceutical discovery and development, while it is also anticipated that human ES cell reagents will revolutionise aspects of regenerative medicine. This review will summarise the advantages, potential and great hope for ES cell based systems in these contexts.