Unlabelled: Polymorphonuclear neutrophil granulocytes (neutrophils) are tightly controlled by an incompletely understood homeostatic feedback loop adjusting the marrow's supply to peripheral needs. Although it has long been known that marrow cellularity is inversely correlated with G-CSF levels, the mechanism linking peripheral clearance to production remains unknown. Herein, the feedback response to antibody induced neutropenia is characterized to consist of G-CSF–dependent shifts of marrow hematopoietic progenitor populations including expansion of the lin-/Sca-1/c-kit (LSK) and granulocyte macrophage progenitor (GMP) compartments at the expense of thrombopoietic and red cell precursors. Evidence is provided that positive feedback regulation is independent from commensal germs as well as T, B, and NK cells. However, in vivo feedback is impaired in TLR4-/- and TRIF-/-, but not MyD88-/- animals. In conclusion, steady-state neutrophil homeostasis is G-CSF–dependent and regulated through pattern-recognition receptors,thereby directly linking TLR-triggering to granulopoiesis.
Key Points: Steady-state and emergency granulopoiesis are both dependent on TLR signaling.
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http://dx.doi.org/10.1182/blood-2012-05-429589 | DOI Listing |
Front Immunol
November 2024
Departamento de Inmunología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico.
Physiol Rep
November 2024
Department of Emergency Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA.
J Biol Chem
October 2024
Signalling Programme, The Babraham Institute, Babraham Research Campus, Cambridge, UK. Electronic address:
Norbin (Neurochondrin, NCDN) is a G protein-coupled receptor (GPCR) adaptor protein known for its importance in neuronal function. Norbin works by binding to numerous GPCRs, controlling their steady-state trafficking and sometimes their agonist-induced internalization, as well as their signaling. We recently showed that Norbin is expressed in neutrophils, limits the surface levels of the GPCRs C5aR1 and CXCR4 in neutrophils, and suppresses neutrophil-mediated innate immunity.
View Article and Find Full Text PDFJ Leukoc Biol
October 2024
School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.
The liver has critical digestive, metabolic, and immunosurveillance roles, which get disrupted during liver diseases such as viral hepatitis, fatty liver disease, and hepatocellular carcinoma. While previous research on the pathological development of these diseases has focused on liver-resident immune populations, such as Kupffer cells, infiltrating immune cells responding to pathogens and disease also play crucial roles. Neutrophils are one such key population contributing to hepatic inflammation and disease progression.
View Article and Find Full Text PDFJ Taibah Univ Med Sci
August 2024
Haematology and Blood Transfusion Science Unit, Department of Medical Laboratory Science, College of Medicine and Health Sciences, Afe Babalola University, Ado - Ekiti, Ekiti, Nigeria.
Objectives: This case-control study investigated the mode of leukocyte function in sickle cell anemia (SCA) to delineate the underlying immunopathology for early diagnosis and mitigate the increased bacterial infection risk in this patient population.
Method: In total, 90 participants comprising 24 hemoglobin (Hb)-AA, 22 Hb-AS, 23 steady state Hb-SS and 21 vaso-occlusive crisis state Hb-SS subjects were recruited for this study. The subjects were further divided into the following six groups: Hb-AA and Hb-AS subjects as control groups, Hb-SS subjects at steady state, Hb-SS subjects in a vaso-occlusive crisis state, Hb-SS subjects undergoing medication (Meds), and Hb-SS subjects undergoing medication plus blood transfusion (Meds/BT) group, respectively.
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