Regulates the Function of Lympho-Myeloid Primed Progenitors after Transplantation.

, a zinc finger E-box binding homeobox epithelial-mesenchymal (EMT) transcription factor, acts as a critical regulator of hematopoietic stem cell (HSC) self-renewal and multi-lineage differentiation. Whether directly regulates the function of multi-potent progenitors primed for hematopoietic lineage commitment remains ill defined. By using an inducible conditional mouse model where was genetically engineered to be deficient in the adult hematopoietic system (hereafter ), we found that the absolute cell number of immunophenotypically defined lympho-myeloid primed progenitors (LMPPs) from mice was reduced.

An alginate-based encapsulation system for delivery of therapeutic cells to the CNS.

Treatment options for neurodegenerative conditions such as Parkinson's disease have included the delivery of cells which release dopamine or neurotrophic factors to the brain. Here, we report the development of a novel approach for protecting cells after implantation into the central nervous system (CNS), by developing dual-layer alginate beads that encapsulate therapeutic cells and release an immunomodulatory compound in a sustained manner. An optimal alginate formulation was selected with a view to providing a sustained physical barrier between engrafted cells and host tissue, enabling exchange of small molecules while blocking components of the host immune response.

Zeb1 modulates hematopoietic stem cell fates required for suppressing acute myeloid leukemia.

Zeb1, a zinc finger E-box binding homeobox epithelial-mesenchymal transition (EMT) transcription factor, confers properties of "stemness," such as self-renewal, in cancer. Yet little is known about the function of Zeb1 in adult stem cells. Here, we used the hematopoietic system as a well-established paradigm of stem cell biology to evaluate Zeb1-mediated regulation of adult stem cells.

Inhibition of GATA2 restrains cell proliferation and enhances apoptosis and chemotherapy mediated apoptosis in human GATA2 overexpressing AML cells.

GATA2, a zinc finger transcription factor predominantly expressed in hematopoietic cells, acts as an essential regulator of hematopoietic stem cell generation, survival and functionality. Loss and gain of GATA2 expression has been implicated in myelodysplastic syndrome and acute myeloid leukemia (AML) yet the precise biological impact of GATA2 expression on human AML cell fate decisions remains ambiguous. Herein, we performed large-scale bioinformatics that demonstrated relatively frequent GATA2 overexpression in AML patients as well as select human AML (or AML-like) cell lines.

Gata2 as a Crucial Regulator of Stem Cells in Adult Hematopoiesis and Acute Myeloid Leukemia.

Subversion of transcription factor (TF) activity in hematopoietic stem/progenitor cells (HSPCs) leads to the development of therapy-resistant leukemic stem cells (LSCs) that drive fulminant acute myeloid leukemia (AML). Using a conditional mouse model where zinc-finger TF Gata2 was deleted specifically in hematopoietic cells, we show that knockout of Gata2 leads to rapid and complete cell-autonomous loss of adult hematopoietic stem cells. By using short hairpin RNAi to target GATA2, we also identify a requirement for GATA2 in human HSPCs.

Isolation and Characterisation of Human Adipose-Derived Stem Cells.

Recently, adipose-derived stem cells (ASCs), obtained from fresh human lipoaspirate, have shown promise as immunomodulatory agents having demonstrated immunosuppressive functionality both in vitro and in vivo. A number of researchers have described the isolation of ASCs through the enzymatic digestion of fat samples, followed by a number of purification steps, involving centrifugation and filtration. Here, we utilize a standard isolation technique, with the added purification of putative ASCs by fluorescence activated cell sorting (FACS).

Stem Cells Cycle toward Immune Surveillance.

Immune surveillance is an established regulatory mechanism that spares tissues from malignant transformation. Agudo et al. (2018) find that the chief cell type to generate tissues in the body-somatic stem cells-is subject to immune surveillance only during proliferation.

Dickkopf-3, a tissue-derived modulator of local T-cell responses.

The adaptive immune system protects organisms from harmful environmental insults. In parallel, regulatory mechanisms control immune responses in order to assure preservation of organ integrity. Yet, molecules involved in the control of T-cell responses in peripheral tissues are poorly characterized.

Lack of immune response to differentiated cells derived from syngeneic induced pluripotent stem cells.

The prospects for using autologous induced pluripotent stem cells (iPSCs) in cell replacement therapy have been tempered by evidence that undifferentiated, syngeneic mouse iPSCs are immunogenic upon transplantation. However, the immunogenicity of more therapeutically relevant differentiated cells remains unexplored. Here, we differentiated mouse iPSCs into embryoid bodies (EBs) or representative cell types spanning the three embryonic germ layers and assessed their immunogenicity in vitro and after their transplantation into syngeneic recipients.

Concise review: Immune recognition of induced pluripotent stem cells.

Autologous-induced pluripotent stem cells (iPSCs) may eventually be used in cell replacement therapies to treat a wide range of diseases and have been touted as a solution to the vexing problem of immune rejection in this context. Emerging evidence suggests, however, that ostensibly histocompatible iPSCs may be rejected following transplantation. Here, we review the mechanisms that contribute to immunogenicity in iPSCs and forward approaches to permit their acceptance in potential cell replacement therapies.

A role for regulatory T cells in acceptance of ESC-derived tissues transplanted across an major histocompatibility complex barrier.

We have previously reported that ESC-derived tissues are subject to some level of immune privilege, which might facilitate induction of immune tolerance. Herein, we further demonstrate that fully allogeneic ESC-derived tissues are accepted with a regimen of coreceptor blockade even in recipients known to be relatively resistant to such a tolerizing protocol. Moreover, ESC-derived tissues could be spontaneously accepted across a class I major histocompatibility complex disparity.

Characteristics of the early immune response following transplantation of mouse ES cell derived insulin-producing cell clusters.

Background: The fully differentiated progeny of ES cells (ESC) may eventually be used for cell replacement therapy (CRT). However, elements of the innate immune system may contribute to damage or destruction of these tissues when transplanted.

Methodology/principal Findings: Herein, we assessed the hitherto ill-defined contribution of the early innate immune response in CRT after transplantation of either ESC derived insulin producing cell clusters (IPCCs) or adult pancreatic islets.

Approaches for immunological tolerance induction to stem cell-derived cell replacement therapies.

The shortage of donors for organ transplantation and also to treat degenerative diseases has led to the development of the new field of regenerative medicine. One aim of this field, in addition to in vivo induction of endogenous tissue regeneration, is to utilize stem cells as a supplementary source of cells to repair or replace tissues or organs that have ceased to function owing to ageing or autoimmunity. Embryonic stem cells hold promise in this respect because of their developmental capacity to generate all tissues within the body.

Variation in MHC expression between undifferentiated mouse ES cells and ES cell-derived insulin-producing cell clusters.

Background: The progeny of embryonic stem (ES) cells may eventually be used to replace damaged tissues in transplantation, yet their immunogenicity remains ill-defined. The major histocompatibility complex (MHC) is a determinant of immunogenicity in transplantation.

Methods And Results: Herein, we show differences in MHC expression between mouse ES cells and ES cell derived insulin producing cell clusters (IPCCs), including a relatively higher expression of MHC Class I in IPCCs and a faster, more dramatic induction of MHC Class I in IPCCs following challenge with interferon-gamma (IFN-gamma).

GATA-2 regulates granulocyte-macrophage progenitor cell function.

The zinc finger transcription factor GATA-2 has been implicated in the regulation of hematopoietic stem cells. Herein, we explored the role of GATA-2 as a candidate regulator of the hematopoietic progenitor cell compartment. We showed that bone marrow from GATA-2 heterozygote (GATA-2(+/-)) mice displayed attenuated granulocyte-macrophage progenitor function in colony-forming cell (CFC) and serial replating CFC assays.

Embryonic stem cells and their differentiated derivatives have a fragile immune privilege but still represent novel targets of immune attack.

Embryonic stem cells (ESCs) offer an attractive potential in cell replacement therapy and regenerative medicine because of their inherent plasticity and ability to self-renew. However, the immunological response against transplanted ESC-derived allografts requires further evaluation. In this study, we showed that ESCs expressing the major histocompatibility complex class I molecule H2K(b) escape immune recognition by H2K(b)-reactive CD8(+) T cells, irrespective of H2K(b) expression levels.

A comparison of protocols used to generate insulin-producing cell clusters from mouse embryonic stem cells.

Embryonic stem cells (ESCs) have the capacity to generate a panoply of tissue types and may therefore provide an alternative source of tissue in regenerative medicine to treat potentially debilitating conditions like Type 1 diabetes mellitus. However, the ability of mouse ESCs to generate insulin-producing cell clusters (IPCCs) remains highly contentious. In an attempt to clarify this issue, three protocols for the ESC-based generation of IPCCs (referred to as Blyszczuk, Hori, and Lumelsky protocols) were modified and evaluated for their ability to express pancreatic islet genes and proteins and their capacity to function.

Embryonic stem cell transplantation: potential applicability in cell replacement therapy and regenerative medicine.

Embryonic stem cells are derived from the inner cell mass of the trophoblast, and have the ability to differentiate into all the tissues of the fetus. As such, their potential in cell replacement therapy and regenerative medicine has been widely acknowledged. Useful cell types such as neurons, cardiomyocytes, hepatocytes, pancreatic beta cells, and blood cells have all been successfully derived in the laboratory.

Transplanting stem cells: potential targets for immune attack. Modulating the immune response against embryonic stem cell transplantation.

The curative promise of stem cells and their descendants for tissue regeneration and repair is currently the subject of an intense research effort worldwide. If it proves feasible to differentiate stem cells into specific tissues reliably and safely, this approach will be invaluable in the treatment of diseases that lead to organ degeneration or failure, providing an alternative or supplementary source of tissue for transplantation. Embryonic stem (ES) cells are pluripotent cells derived from the inner cell mass of a pre-implantation blastocyst that can produce all cells and tissues of the foetus.

Haploinsufficiency of GATA-2 perturbs adult hematopoietic stem-cell homeostasis.

The zinc finger transcription factor GATA-2 plays a fundamental role in generating hematopoietic stem-cells in mammalian development. Less well defined is whether GATA-2 participates in adult stem-cell regulation, an issue we addressed using GATA-2 heterozygote mice that express reduced levels of GATA-2 in hematopoietic cells. While GATA-2+/- mice demonstrated decreases in some colony-forming progenitors, the most prominent changes were observed within the stem-cell compartment.