Tissue-resident myeloid (TRM) cells in adults have highly variable lifespans, and may be derived from early embryonic yolk sac, fetal liver, or bone marrow. Some of these TRM cells are known pathogenic participants in congenital and acquired diseases. Myeloablative conditioning and hematopoietic stem cell transplantation can replace long-lived brain TRM cells, resulting in clinical improvements in metabolic storage diseases.
View Article and Find Full Text PDFTissue resident myeloid cells (TRM) in adults have highly variable lifespans and may be derived from early embryonic yolk sac, fetal liver or bone marrow. Some of these TRM are known pathogenic participants in congenital and acquired diseases. Myeloablative conditioning and hematopoietic stem cell transplant can replace long-lived brain TRM resulting in clinical improvements in metabolic storage diseases.
View Article and Find Full Text PDFConditioning chemotherapy is used to deplete hematopoietic stem cells in the recipient's marrow, facilitating donor cell engraftment. Although effective, a major issue with chemotherapy is the systemic genotoxicity that increases the risk for secondary malignancies. Antibody conjugates targeting hematopoietic cells are an emerging non-genotoxic method of opening the marrow niche and promoting engraftment of transplanted cells while maintaining intact marrow cellularity.
View Article and Find Full Text PDFThe goal of high-throughput screening is to enable screening of compound libraries in an automated manner to identify quality starting points for optimization. This often involves screening a large diversity of compounds in an assay that preserves a connection to the disease pathology. Phenotypic screening is a powerful tool for drug identification, in that assays can be run without prior understanding of the target and with primary cells that closely mimic the therapeutic setting.
View Article and Find Full Text PDFClinical application of umbilical cord blood (UCB) as a source of hematopoietic stem cells for transplantation is limited by low CD34+ cell dose, increased risk of graft failure, and slow hematopoietic recovery. While the cell dose limitation is partially mitigated by using two UCB units, larger-dosed single units would be preferable. We have evaluated the feasibility and safety of StemRegenin-1 (SR-1), an aryl hydrocarbon receptor antagonist that expands CD34+ cells, by placing one of the two units in expansion culture.
View Article and Find Full Text PDFThe use of umbilical cord blood (UCB) as an alternative haematopoietic cell source in lieu of bone marrow for haematopoietic reconstitution is increasingly becoming a mainstay treatment for both malignant and nonmalignant diseases, as most individuals will have at least one available, suitably HLA-matched unit of blood. The principal limitation of UCB is the low and finite number of haematopoietic stem and progenitor cells (HSPC) relative to the number found in a typical bone marrow or mobilized peripheral blood allograft, which leads to prolonged engraftment times. In an attempt to overcome this obstacle, strategies that are often based on native processes occurring in the bone marrow microenvironment or 'niche' have been developed with the goal of accelerating UCB engraftment.
View Article and Find Full Text PDFHematopoietic stem cells (HSCs) are the progenitor cells that give rise to all blood cells. The ability to control HSC differentiation has the potential to improve the success of bone marrow transplants and the production of functional blood cells ex vivo. Here we performed an unbiased screen using primary human CD34(+) hematopoietic stem and progenitor cells (HSPCs) to identify natural products that selectively control their differentiation.
View Article and Find Full Text PDFTo identify small molecules that selectively control hematopoietic stem cell differentiation, we performed an unbiased screen using primary human CD34(+) cells. We identified a plant-derived natural product, euphohelioscopin A, capable of selectively differentiating CD34(+) cells down the granulocyte/monocytic lineage. Euphohelioscopin A also inhibits proliferation and induces differentiation of the myeloid leukemia cell lines THP-1 and HL-60.
View Article and Find Full Text PDFMolecules that control the lineage commitment of hematopoietic stem cells (HSCs) may allow the expansion of enriched progenitor populations for both research and therapeutic uses. In an effort to better understand and control the differentiation of HSCs to megakaryocytes, we carried out an image-based screen of a library of 50,000 heterocycles using primary human CD34(+) cells. A class of naphthyridinone derivatives was identified that induces the differentiation of common myeloid progenitors (CMP) to megakaryocytes.
View Article and Find Full Text PDFClinical hematopoietic transplantation outcomes are strongly correlated with the numbers of cells infused. Anticipated novel therapeutic implementations of hematopoietic stem cells (HSCs) and their derivatives further increase interest in strategies to expand HSCs ex vivo. A fundamental limitation in all HSC-driven culture systems is the rapid generation of differentiating cells and their secreted inhibitory feedback signals.
View Article and Find Full Text PDFThe biological functions of the aryl hydrocarbon receptor (AHR) can be delineated into dioxin response element (DRE)-dependent or -independent activities. Ligands exhibiting either full or partial agonist activity, e.g.
View Article and Find Full Text PDFPotential applications of stem cells in medicine range from their inclusion in disease modeling and drug discovery to cell transplantation and regenerative therapies. However, before this promise can be realized several obstacles must be overcome, including the control of stem cell differentiation, allogeneic rejection and limited cell availability. This will require an improved understanding of the mechanisms that govern stem cell potential and the development of robust methods to efficiently control their fate.
View Article and Find Full Text PDFAlthough practiced clinically for more than 40 years, the use of hematopoietic stem cell (HSC) transplants remains limited by the ability to expand these cells ex vivo. An unbiased screen with primary human HSCs identified a purine derivative, StemRegenin 1 (SR1), that promotes the ex vivo expansion of CD34+ cells. Culture of HSCs with SR1 led to a 50-fold increase in cells expressing CD34 and a 17-fold increase in cells that retain the ability to engraft immunodeficient mice.
View Article and Find Full Text PDFBz-423 is a pro-apoptotic 1,4-benzodiazepine with therapeutic properties in murine models of lupus demonstrating selectivity for autoreactive lymphocytes. Bz-423 modulates the F(1)F(0)-ATPase, inducing the formation of superoxide within the mitochondrial respiratory chain, which then functions as a second messenger initiating apoptosis. In order to understand some of the features that contribute to the increased sensitivity of lymphocytes, we report the signaling pathway engaged by Bz-423 in a Burkitt lymphoma cell line (Ramos).
View Article and Find Full Text PDFBz-423 is a proapoptotic 1,4-benzodiazepine with potent therapeutic properties in murine models of lupus and psoriasis. Bz-423 modulates the F(1)F(0)-ATPase, inducing the formation of superoxide within the mitochondrial respiratory chain, which then functions as a second messenger initiating apoptosis. Herein, we report the signaling pathway activated by Bz-423 in mouse embryonic fibroblasts containing knockouts of key apoptotic proteins.
View Article and Find Full Text PDFBz-423 is a new benzodiazepine that has cytotoxic and cytostatic effects against a number of cell types in culture, and recent studies have shown efficacy in experimental lupus models in rodents. The present study demonstrates that treating human skin in organ culture with Bz-423 suppresses retinoid-induced epidermal hyperplasia. Bz-423 suppresses hyperplasia in organ culture at concentrations that also inhibit keratinocyte proliferation in monolayer culture but that are not cytotoxic for keratinocytes and do not inhibit fibroblast growth.
View Article and Find Full Text PDFBz-423 is a 1,4-benzodiazepine with selective lymphotoxic properties and potent therapeutic activity against lupus-like disease in autoimmune mice. In NZB/W lupus-prone mice, Bz-423 specifically kills germinal center B cells, which are the cells that drive disease both in this model and in human systemic lupus erythematosus. In this report, the mechanistic basis for the selective action of Bz-423 is investigated.
View Article and Find Full Text PDFResveratrol (3,5,4-trihydroxystilbene), a natural phytoalexin present in grapes, nuts, and red wine, has antineoplastic activities. Several molecular mechanisms have been described to underlie its effects on cells in vitro and in vivo. In the present study, the response of ovarian cancer cells to resveratrol is explored.
View Article and Find Full Text PDFThe NFkappaB transcription factors can both promote cell survival and induce apoptosis depending on cell type and context. Neuroblastoma (NB) cells display two predominant culture phenotypes identified as N- and S-types. Malignant S-type cells express neither high levels of MYCN nor Bcl-2, suggesting that other survival mechanisms are important.
View Article and Find Full Text PDFThe substrate oxidation rates of P450(BM-3) are unparalleled in the cytochrome P450 (CYP) superfamily of enzymes. Furthermore, the bacterial enzyme, originating from Bacillus megaterium, has been used repeatedly as a model to study the metabolism of mammalian P450s. A specific example is presented where studying P450(BM-3) substrate dynamics can define important enzyme-substrate characteristics, which may be useful in modeling omega-hydroxylation seen in mammalian P450s.
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