Browsing by Author "King, Katherine Y."

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    Chronic Infection Depletes Hematopoietic Stem Cells through Stress-Induced Terminal Differentiation
    (Cell Press, 2016) Matatall, Katie A.; Jeong, Mira; Chen, Siyi; Sun, Deqiang; Chen, Fengju; Mo, Qianxing; Kimmel, Marek; King, Katherine Y.
    Chronic infections affect a third of the world’s population and can cause bone marrow suppression, a severe condition that increases mortality from infection. To uncover the basis for infection-associated bone marrow suppression, we conducted repeated infection of WT mice with Mycobacterium avium. After 4–6 months, mice became pancytopenic. Their hematopoietic stem and progenitor cells (HSPCs) were severely depleted and displayed interferon gamma (IFN-γ) signaling-dependent defects in self-renewal. There was no evidence of increased HSPC mobilization or apoptosis. However, consistent with known effects of IFN-γ, transcriptome analysis pointed toward increased myeloid differentiation of HSPCs and revealed the transcription factor Batf2 as a potential mediator of IFN-γ-induced HSPC differentiation. Gain- and loss-of-function studies uncovered a role for Batf2 in myeloid differentiation in both murine and human systems. We thus demonstrate that chronic infection can deplete HSPCs and identify BATF2 as a mediator of infection-induced HSPC terminal differentiation.
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    Genomic trajectory in leukemogenesis of myeloproliferative neoplasms: a case report
    (BioMed Central, 2021) Chen, Yujie; Talukder, Rafee; Merritt, Brian Y.; King, Katherine Y.; Kimmel, Marek; Rivero, Gustavo; Sosa, Romina
    We report a patient with Essential Thrombocythemia (ET), subsequently diagnosed with concurrent myeloid and lymphoid leukemia. Generally, the molecular mechanisms underlying leukemic transformation of Philadelphia-negative myeloproliferative neoplasms (Ph-MPN) are poorly understood. Risk of transformation to acute myelogenous leukemia (AML) is low; transformation to both AML and acute lymphoblastic leukemia (ALL) is extremely low. Genetic defects, including allele burden, order of mutation acquisition, clonal heterogeneity and epigenetic mechanisms are important contributors to disease acceleration.
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    Interferon Gamma Mediates Hematopoietic Stem Cell Activation and Niche Relocalization through BST2
    (Cell Press, 2020) Florez, Marcus A.; Matatall, Katie A.; Jeong, Youngjae; Ortinau, Laura; Shafer, Paul W.; Lynch, Anne M.; Jaksik, Roman; Kimmel, Marek; Park, Dongsu; King, Katherine Y.
    During chronic infection, the inflammatory cytokine interferon gamma (IFNγ) damages hematopoietic stem cells (HSCs) by disrupting quiescence and promoting excessive terminal differentiation. However, the mechanism by which IFNγ hinders HSC quiescence remains undefined. Using intravital 3-dimensional microscopy, we find that IFNγ disrupts the normally close interaction between HSCs and CXCL12-abundant reticular (CAR) cells in the HSC niche. IFNγ stimulation increases expression of the cell surface protein BST2, which we find is required for IFNγ-dependent HSC relocalization and activation. IFNγ stimulation of HSCs increases their E-selectin binding by BST2 and homing to the bone marrow, which depends on E-selectin binding. Upon chronic infection, HSCs from mice lacking BST2 are more quiescent and more resistant to depletion than HSCs from wild-type mice. Overall, this study defines a critical mechanism by which IFNγ promotes niche relocalization and activation in response to inflammatory stimulation and identifies BST2 as a key regulator of HSC quiescence.