flow-cytometry-analysis-murine-bone-marrow-hematopoietic-stem

Flow Cytometry Analysis of Murine Bone Marrow Hematopoietic Stem and Progenitor Cells and Stromal Niche Cells

The bone marrow (BM) is the soft tissue found within bones where hematopoiesis, the process by which new blood cells are generated, primarily occurs. As ...

Universidade do Porto

Instituto Português de Oncologia (IPO)-Porto

Faculdade de Medicina da Universidade do Porto

Porto Comprehensive Cancer Center (P.CCC)

Endothelial (EMPs) and platelet microparticles (PMPs) have been studied as biomarkers in several inflammatory diseases and as central players in intercellular communication.

Increased circulating platelet microparticles as a potential biomarker in asthma.

Bone marrow vascular niches sustain hematopoietic stem cells (HSCs) and are drastically remodeled in leukemia to support pathological functions. Acute myeloid leukemia (AML) cells produce angiogenic factors, which likely contribute to this remodeling, but anti-angiogenic therapies do not improve AML patient outcomes. Using intravital microscopy, we found that AML progression leads to differential remodeling of vasculature in central and endosteal bone marrow regions. Endosteal AML cells produce pro-inflammatory and anti-angiogenic cytokines and gradually degrade endosteal endothelium, stromal cells, and osteoblastic cells, whereas central marrow remains vascularized and splenic vascular niches expand. Remodeled endosteal regions have reduced capacity to support non-leukemic HSCs, correlating with loss of normal hematopoiesis. Preserving endosteal endothelium with the small molecule deferoxamine or a genetic approach rescues HSCs loss, promotes chemotherapeutic efficacy, and enhances survival. These findings suggest that preventing degradation of the endosteal vasculature may improve current paradigms for treating AML.

Inhibition of Endosteal Vascular Niche Remodeling Rescues Hematopoietic Stem Cell Loss in AML.

Polyphenols present in some alcoholic beverages have been linked to beneficial effects in preventing cardiovascular diseases. Polyphenols found in beer with anti-proliferative and anti-cancer properties are appealing in the context of the quasi-malignant phenotype of pulmonary arterial hypertension (PAH). Our purpose was to evaluate if the chronic ingestion of a xanthohumol-fortified beer (FB) would be able to modulate the pathophysiology of experimental PAH. Male Wistar rats with monocrotaline (MCT)-induced PAH (60 mg/kg) were allowed to drink either xanthohumol-fortified beer (MCT + FB) or 5.2% ethanol (MCT + SHAM) for a period 4 weeks. At the end of the protocol, cardiopulmonary exercise testing and hemodynamic recordings were performed, followed by sample collection for further analysis. FB intake resulted in a significant attenuation of the pulmonary vascular remodeling in MCT + FB animals. This improvement was paralleled with the downregulation in expression of proteins responsible for proliferation (ERK1/2), cell viability (AKT), and apoptosis (BCL-XL). Moreover, MCT + FB animals presented improved right ventricle (RV) function and remodeling accompanied by VEGFR-2 pathway downregulation. The present study demonstrates that a regular consumption of xanthohumol through FB modulates major remodeling pathways activated in experimental PAH.

Anti-Remodeling Effects of Xanthohumol-Fortified Beer in Pulmonary Arterial Hypertension Mediated by ERK and AKT Inhibition.

 Iron is an essential element required for sustaining a normal healthy life. However, an excess amount of iron in the bloodstream and tissue generates toxic hydroxyl radicals through Fenton reactions. Henceforth, a balance in iron concentration is extremely important to maintain cellular homeostasis in both normal hematopoiesis and erythropoiesis. Iron deficiency or iron overload can impact hematopoiesis and is associated with many hematological diseases.  The mechanisms of action of key iron regulators such as erythroferrone and the discovery of new drugs, such as ACE-536/luspatercept, are of potential interest to treat hematological disorders, such as β-thalassemia. New therapies targeting inflammation-induced ineffective erythropoiesis are also in progress. Furthermore, emerging evidences support differential interactions between iron and its cellular antioxidant responses of hematopoietic and neighboring stromal cells. Both iron and its systemic regulator, such as hepcidin, play a significant role in regulating erythropoiesis.  Significant pre-clinical studies are on the way and new drugs targeting iron metabolism have been recently approved or are undergoing clinical trials to treat pathological conditions with impaired erythropoiesis such as myelodysplastic syndromes or β-thalassemia.  Future studies should explore how iron regulates hematopoiesis in both benign and malignant conditions.  35, 415-432.

The Role of Iron in Benign and Malignant Hematopoiesis.

Acute myeloid leukemia (AML) is a heterogeneous disease with poor prognosis and limited treatment strategies. Determining the role of cell-extrinsic regulators of leukemic cells is vital to gain clinical insights into the biology of AML. Iron is a key extrinsic regulator of cancer, but its systemic regulation remains poorly explored in AML. To address this question, we studied iron metabolism in patients with AML at diagnosis and explored the mechanisms involved using the syngeneic MLL-AF9-induced AML mouse model. We found that AML is a disorder with a unique iron profile, not associated with inflammation or transfusion, characterized by high ferritin, low transferrin, high transferrin saturation (TSAT), and high hepcidin. The increased TSAT in particular, contrasts with observations in other cancer types and in anemia of inflammation. Using the MLL-AF9 mouse model of AML, we demonstrated that the AML-induced loss of erythroblasts is responsible for iron redistribution and increased TSAT. We also show that AML progression is delayed in mouse models of systemic iron overload and that elevated TSAT at diagnosis is independently associated with increased overall survival in AML. We suggest that TSAT may be a relevant prognostic marker in AML.

Loss of erythroblasts in acute myeloid leukemia causes iron redistribution with clinical implications.

Editorial: The Dynamic Interface Between Vascular Blood Vessels to Blood Forming Hematopoietic Stem Cells in Health and Disease.

Ferritin Increase in Hemochromatosis Subjects After Discontinuing Their Regular Maintenance Treatment: A Longitudinal Analysis Performed During the COVID-19 Imposed Hospital Lockdown.

Article	Year
Increased circulating platelet microparticles as a potential biomarker in asthma. Allergy\| PubMed ID: 23889600	2013
Inhibition of Endosteal Vascular Niche Remodeling Rescues Hematopoietic Stem Cell Loss in AML. Cell stem cell\| PubMed ID: 29276143	2018
Anti-Remodeling Effects of Xanthohumol-Fortified Beer in Pulmonary Arterial Hypertension Mediated by ERK and AKT Inhibition. Nutrients\| PubMed ID: 30857304	2019
The Role of Iron in Benign and Malignant Hematopoiesis. Antioxidants & redox signaling\| PubMed ID: 33231101	2021
Loss of erythroblasts in acute myeloid leukemia causes iron redistribution with clinical implications. Blood advances\| PubMed ID: 34402883	2021
Editorial: The Dynamic Interface Between Vascular Blood Vessels to Blood Forming Hematopoietic Stem Cells in Health and Disease. Frontiers in cell and developmental biology\| PubMed ID: 35309923	2022
Ferritin Increase in Hemochromatosis Subjects After Discontinuing Their Regular Maintenance Treatment: A Longitudinal Analysis Performed During the COVID-19 Imposed Hospital Lockdown. HemaSphere\| PubMed ID: 36034093	2022

Delfim Duarte

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