Induced Pluripotent Stem Cells Can Effectively Differentiate into Multiple Functional Lymphocyte Lineages In Vivo with Negligible Bias

Generation of Lungs by Blastocyst Complementation in Apneumic Fgf10-Deficient Mice

The shortage of donor lungs hinders lung transplantation, the only definitive option for patients with end-stage lung disease. Blastocyst complementation enables the generation of transplantable organs from pluripotent stem cells (PSCs) in animal models. Pancreases and kidneys have been generated from PSCs by blastocyst complementation in rodent models. Here, we report the generation of lungs using mouse embryonic stem cells (ESCs) in apneumic Fgf10 Ex1^mut/Ex3^mutmice by blastocyst complementation. Complementation with ESCs enables Fgf10-deficient mice to survive to adulthood without abnormalities. Both the generated lung alveolar parenchyma and the interstitial portions, including vascular endothelial cells, vascular and parabronchial smooth muscle cells, and connective tissue, largely originate from the injected ESCs. These data suggest that Fgf10 Ex1^mut/Ex3^mutblastocysts provide an organ niche for lung generation and that blastocyst complementation could be a viable approach for generating whole lungs.

Dose- and Time-Dependent Effects of Human Mesenchymal Stromal Cell Infusion on Cardiac Allograft Rejection in Mice

Heart transplantation is the final life-saving therapeutic strategy for many end-stage heart diseases. Long-term immunosuppressive regimens are needed to prevent allograft rejection. Mesenchymal stromal cells (MSCs) have been shown as immunomodulatory therapy for organ transplantation. However, the effect of dose and timing of MSC treatment on heart transplantation has not yet been examined. In this study, we infused three doses (1 × 106, 2 × 106, or 5 × 106 cells) of human MSCs (hMSCs) to the recipient BALB/c mice before (7 days or 24 h) or after (24 h) receiving C57BL/6 cardiac transplants. We found that infusion of high dose hMSCs (5 × 106) at 24 h post-transplantation significantly prolonged the survival time of cardiac grafts. To delineate the underlying mechanism, grafts, spleens, and draining lymph nodes were harvested for analysis. Dose-dependent effect of hMSC treatment was shown in: (1) alleviation of International Society of Heart and Lung Transplantation (ISHLT) score in grafts; (2) reduction of the population of CD4+ and CD8+ T cells; (3) increase of regulatory T (Treg) cells; (4) and decrease of serum levels of inflammatory cytokines and donor-specific antibodies. Taken together, we showed timing critical and dose-dependent immunomodulatory effects of hMSC treatment against acute allograft rejection in a mouse model of heart transplantation.

Beyond CAR-T cells: Natural killer cells immunotherapy

Children and adolescents suffering from refractory leukaemia, relapse after stem cell transplantation, solid metastatic tumour or refractory to conventional treatments still condition a dismal prognosis. The critical role of the immune system in the immunosurveillance of cancer is becoming relevant with the development of new treatments such as the checkpoint inhibitor drugs and genetic modified T lymphocytes, tisagenlecleucel or axicabtagene ciloleucel. In addition, other immunotherapies are being developed such as cell therapy with natural killer (NK) lymphocytes. The rapid and potent cytotoxic activity of NK cells respecting healthy cells and the possibility of expansion, manipulating them and combining them with other treatments, make these cells a powerful therapeutic tool to be developed, with a very high safety profile. Furthermore, new strategies are being developed to increase the therapeutic benefit of NK cells such as genetic manipulation for the expression of chimeric antigen receptors.

Toward Immunocompetent 3D Skin Models

3D human skin models provide a platform for toxicity testing, biomaterials evaluation, and investigation of fundamental biological processes. However, the majority of current in vitro models lack an inflammatory system, vasculature, and other characteristics of native skin, indicating scope for more physiologically complex models. Looking at the immune system, there are a variety of cells that could be integrated to create novel skin models, but to do this effectively it is also necessary to understand the interface between skin biology and tissue engineering as well as the different roles the immune system plays in specific health and disease states. Here, a progress report on skin immunity and current immunocompetent skin models with a focus on construction methods is presented; scaffold and cell choice as well as the requirements of physiologically relevant models are elaborated. The wide range of technological and fundamental challenges that need to be addressed to successfully generate immunocompetent skin models and the steps currently being made globally by researchers as they develop new models are explored. Induced pluripotent stem cells, microfluidic platforms to control the model environment, and new real-time monitoring techniques capable of probing biochemical processes within the models are discussed.

Progress and Future Prospectives in Skin-on-Chip Development with Emphasis on the use of Different Cell Types and Technical Challenges

Understanding the healthy and diseased state of skin is important in many areas of basic and applied research. Although the field of skin tissue engineering has advanced greatly over the last years, current in vitro skin models still do not mimic the complexity of the human skin. Skin-on-chip and induced pluripotent stem cells (iPSC) might be key technologies to improve in vitro skin models. This review summarizes the state of the art of in vitro skin models with regard to cell sources (primary, cell line, iPSC) and microfluidic devices. It can be concluded that iPSC have the potential to be differentiated into many kinds of immunologically matched cells and skin-on-chip technology might lead to more physiologically relevant skin models due to the controlled environment, possible exchange of immune cells, and an increased barrier function. Therefore the combination of iPSC and skin-on-chip is expected to lead to superior healthy and diseased in vitro skin models.

Manufacturing Natural Killer Cells as Medicinal Products

Natural Killer (NK) cells are innate lymphoid cells (ILC) with cytotoxic and regulatory properties. Their functions are tightly regulated by an array of inhibitory and activating receptors, and their mechanisms of activation strongly differ from antigen recognition in the context of human leukocyte antigen presentation as needed for T-cell activation. NK cells thus offer unique opportunities for new and improved therapeutic manipulation, either in vivo or in vitro, in a variety of human diseases, including cancers. NK cell activity can possibly be modulated in vivo through direct or indirect actions exerted by small molecules or monoclonal antibodies. NK cells can also be adoptively transferred following more or less substantial modifications through cell and gene manufacturing, in order to empower them with new or improved functions and ensure their controlled persistence and activity in the recipient. In the present review, we will focus on the technological and regulatory challenges of NK cell manufacturing and discuss conditions in which these innovative cellular therapies can be brought to the clinic.

iPS Cells-The Triumphs and Tribulations

The year 2006 will be remembered monumentally in science, particularly in the stem cell biology field, for the first instance of generation of induced pluripotent stem cells (iPSCs) from mouse embryonic/adult fibroblasts being reported by Takahashi and Yamanaka. A year later, human iPSCs (hiPSCs) were generated from adult human skin fibroblasts by using quartet of genes, Oct4, Sox2, Klf4, and c-Myc. This revolutionary technology won Yamanaka Nobel Prize in Physiology and Medicine in 2012. Like human embryonic stem cells (hESCs), iPSCs are pluripotent and have the capability for self-renewal. Moreover, complications of immune rejection for therapeutic applications would be greatly eliminated by generating iPSCs from individual patients. This has enabled their use for drug screening/discovery and disease modelling in vitro; and for immunotherapy and regenerative cellular therapies in vivo, paving paths for new therapeutics. Although this breakthrough technology has a huge potential, generation of these unusual cells is still slow, ineffectual, fraught with pitfalls, and unsafe for human use. In this review, I describe how iPSCs are being triumphantly used to lay foundation for a fully functional discipline of regenerative dentistry and medicine, alongside discussing the challenges of translating therapies into clinics. I also discuss their future implications in regenerative dentistry field.