Scientific Resources

The classical model of hematopoiesis predicts a dichotomous lineage restriction of multipotent hematopoietic progenitors (MPPs) into common lymphoid progenitors (CLPs) and common myeloid progenitors (CMPs). However,this idea has been challenged by the identification of lymphoid progenitors retaining partial myeloid potential (e.g.,LMPPs),implying that granulocytes can arise within both the classical lymphoid and the myeloid branches. Here,we resolve this issue by using cell-surface CD133 expression to discriminate functional progenitor populations. We show that eosinophilic and basophilic granulocytes as well as erythrocytes and megakaryocytes derive from a common erythro-myeloid progenitor (EMP),whereas neutrophilic granulocytes arise independently within a lympho-myeloid branch with long-term progenitor function. These findings challenge the concept of a CMP and restore dichotomy to the classical hematopoietic model. View Publication

Dysregulation of the JAK/STAT signaling pathway is associated with Multiple Sclerosis (MS) and its mouse model,Experimental Autoimmune Encephalomyelitis (EAE). Suppressors Of Cytokine Signaling (SOCS) negatively regulate the JAK/STAT pathway. We previously reported a severe,brain-targeted,atypical form of EAE in mice lacking Socs3 in myeloid cells (Socs3DeltaLysM),which is associated with cerebellar neutrophil infiltration. There is emerging evidence that neutrophils are detrimental in the pathology of MS/EAE,however,their exact function is unclear. Here we demonstrate that neutrophils from the cerebellum of Socs3DeltaLysM mice show a hyper-activated phenotype with excessive production of reactive oxygen species (ROS) at the peak of EAE. Neutralization of ROS in vivo delayed the onset and reduced severity of atypical EAE. Mechanistically,Socs3-deficient neutrophils exhibit enhanced STAT3 activation,a hyper-activated phenotype in response to G-CSF,and upon G-CSF priming,increased ROS production. Neutralization of G-CSF in vivo significantly reduced the incidence and severity of the atypical EAE phenotype. Overall,our work elucidates that hypersensitivity of G-CSF/STAT3 signaling in Socs3DeltaLysM mice leads to atypical EAE by enhanced neutrophil activation and increased oxidative stress,which may explain the detrimental role of G-CSF in MS patients. View Publication