During mammalian ontogeny, haematopoietic stem cells (HSCs) translocate from the fetal liver to the bone marrow, where haematopoiesis occurs throughout adulthood. Unique features of bone that contribute to a microenvironmental niche for stem cells might include the known high concentration of calcium ions at the HSC-enriched endosteal surface. Cells respond to extracellular ionic calcium concentrations through the seven-transmembrane-spanning calcium-sensing receptor (CaR), which we identified as being expressed on HSCs. Here we show that, through the CaR, the simple ionic mineral content of the niche may dictate the preferential localization of adult mammalian haematopoiesis in bone. Antenatal mice deficient in CaR had primitive haematopoietic cells in the circulation and spleen, whereas few were found in bone marrow. CaR-/- HSCs from fetal liver were normal in number, in proliferative and differentiative function, and in migration and homing to the bone marrow. Yet they were highly defective in localizing anatomically to the endosteal niche, behaviour that correlated with defective adhesion to the extracellular matrix protein, collagen I. CaR has a function in retaining HSCs in close physical proximity to the endosteal surface and the regulatory niche components associated with it.
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http://dx.doi.org/10.1038/nature04247 | DOI Listing |
J Pediatr Hematol Oncol
January 2025
Department of Pediatrics, Teerthanker Mahaveer Medical College and Research Center, TMU, Moradabad, Uttar Pradesh, India.
Leukemia symptoms occurring in the first 4 weeks of infancy are known as congenital leukemia. We present a case of congenital leukemia in a full-term neonate manifesting at birth with a grossly distended abdomen due to a large abdominal mass. Ultrasonography of the abdomen showed a large abdominal mass originating from the liver.
View Article and Find Full Text PDFAdv Sci (Weinh)
January 2025
Translational Medical Center, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, 450001, China.
Immune thrombocytopenia (ITP) is an autoimmune disorder characterized by reduced platelet levels and heightened susceptibility to bleeding resulting from augmented autologous platelet destruction and diminished thrombopoiesis. Although antibody-mediated autoimmune reactions are widely recognized as primary factors, the precise etiological agents that trigger ITP remain unidentified. The pathogenesis of ITP remains unclear owing to the absence of comprehensive high-throughput data, except for the belated emergence of autoreactive antibodies.
View Article and Find Full Text PDFFEBS J
January 2025
Department of Pharmacology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Germany.
Creatine is essential for ATP regeneration in energy-demanding cells. Creatine deficiency results in severe neurodevelopmental impairments. In the brain, creatine is synthesized locally by oligodendrocytes to supply neighboring neurons.
View Article and Find Full Text PDFTransplantation
January 2025
Department of Surgery, Center for Transplantation Sciences, Massachusetts General Hospital, Harvard Medical School, Boston, MA.
Background: Long-term renal allograft acceptance has been achieved in macaques using a transient mixed hematopoetic chimerism protocol, but similar regimens have proven unsuccessful in heart allograft recipients unless a kidney transplant was performed simultaneously. Here, we test whether a modified protocol based on targeting CD154, CD2, and CD28 is sufficient to prolong heart allograft acceptance or promote the expansion of regulatory T cells.
Methods: Eight macaques underwent heterotopic allo-heart transplantation from major histocompatibility complex-mismatched donors.
J Cancer Res Ther
December 2024
Institute of Infection, Immunology and Tumor Microenvironment, Hubei Province Key Laboratory of Occupational Hazard Identification and Control, School of Medicine, Wuhan University of Science and Technology, Wuhan, China.
Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is one of the most important methods for treating a wide range of hematologic malignancies and bone marrow failure diseases. However, graft-versus-host disease (GVHD), a major complication associated with this method, can seriously affect the survival and quality of life of patients. Acute GVHD (aGVHD) occurs within 100 days after transplantation, and gastrointestinal aGVHD (GI-aGVHD) is one of the leading causes of nonrecurrent death after allo-HSCT.
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