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Rowe, G.

Publications and source records attributed to Rowe, G..

5 recordsLinked to original sources

RNA splicing factor mutations drive myeloid neoplasm oncogenesis through protein complex poisoning

RNA splicing factor mutations (SFmut) are founding oncogenic events which cause RNA splicing errors with unpredictable gene expression dynamics. Despite extensive transcriptomic studies, SFmut cancer-initiating mechanisms remain elusive. Among SFmut cancers, myeloid neoplasms (MN) alone offer a setting where true cancer-driving SFmut stem cells can be identified, namely the hematopoietic stem cell (HSC). Within a cohort of 62 MN patients and 20 healthy donors, we conducted long/short-read single-cell transcriptomics (10X-ONT, n = 21) and immunophenotype-resolved low-cell proteomics (pauciproteomics, n = 78) to resolve gene expression, RNA splicing and protein expression dynamics across healthy and SFmut MN hematopoiesis. During hematopoietic differentiation, SFmut RNA mis-splicing decouples proteotranscriptomic dynamics in a mutation-specific manner. Pauciproteomics defines the functional effects of SFmut RNA mis-splicing on the protein layer, identifying early-stage protein effects which poison entire functional protein complexes and progressively disrupt the proteome-wide network during cellular maturation. Importantly, this information could neither be resolved nor predicted by transcriptomic analyses. Finally, we functionally validate the proteome dynamics of HSC through induced pluripotent stem cell culture models of early hematopoietic differentiation, identifying candidate mechanisms for SFmut oncogenesis. Overall, these data elucidate SFmut MN disease biology with unprecedented granularity, defining the molecular consequences of SFmut RNA mis-splicing and offering a generalizable framework for cancer stem cell studies.

cancer biology↗

Dynamic activity of Erg promotes aging of the hematopoietic system

Hematopoiesis changes to adapt to the physiology of development and aging. Temporal changes in hematopoiesis parallel age-dependent incidences of blood diseases. Several heterochronic regulators of hematopoiesis have been identified, but how the master transcription factor (TF) circuitry of definitive hematopoietic stem cells (HSCs) adapts over the lifespan is unknown. Here, we show that expression of the ETS family TF Erg is adult-biased, and that programmed upregulation of Erg expression during juvenile to adult aging is evolutionarily conserved and required for complete implementation of adult patterns of HSC self-renewal and myeloid, erythroid, and lymphoid differentiation. Erg deficiency maintains fetal transcriptional and epigenetic programs, and persistent juvenile phenotypes in Erg haploinsufficient mice are dependent on deregulation of the fetal-biased TF Hmga2. Finally, Erg haploinsufficiency in the adult results in fetal-like resistance to leukemogenesis. Overall, we identify a mechanism whereby HSC TF networks are rewired to specify stage-specific hematopoiesis, a finding directly relevant to age-biased blood diseases. SUMMARYThe hematopoietic system undergoes a process of coordinated aging from the juvenile to adult states. Here, we find that expression of ETS family transcription factor Erg is temporally regulated. Impaired upregulation of Erg during the hematopoietic maturation results in persistence of juvenile phenotypes.

developmental biology↗

Developmental maturation of the hematopoietic system controlled by a Lin28b-let-7-PRC1 axis

Hematopoiesis changes over life to meet the demands of maturation and aging. Here, we find that the definitive hematopoietic stem and progenitor cell (HSPC) compartment is remodeled from gestation into adulthood, a process regulated by the heterochronic Lin28b/let-7 axis. Native fetal and neonatal HSPCs distribute with a pro-lymphoid/erythroid bias with a shift toward myeloid output in adulthood. By mining transcriptomic data comparing juvenile and adult HSPCs and reconstructing coordinately activated gene regulatory networks, we uncover the Polycomb repressor complex 1 (PRC1) component Cbx2 as an effector of Lin28b/let-7s control of hematopoietic maturation. We find that juvenile Cbx2-/- hematopoietic tissues show impairment of B-lymphopoiesis and a precocious adult-like myeloid bias and that Cbx2/PRC1 regulates developmental timing of expression of key hematopoietic transcription factors. These findings define a novel mechanism of epigenetic regulation of HSPC output as a function of age with potential impact on age-biased pediatric and adult blood disorders.

developmental biology↗

Hematopoiesis at single cell resolution spanning human development and maturation

Hematopoiesis is a process of constitutive regeneration whereby hematopoietic stem and progenitor cells (HSPCs) replenish mature blood cells. During maturation and aging, HSPCs shift their output to support the demands of prenatal development and postnatal maturation both at homeostasis and in response to stress. How HSPC ontogeny changes throughout life is unknown; studies to date have largely focused on specific individual ages, particularly at single cell resolution. Here, we performed single cell RNA-seq of human HSPCs from early prenatal development into mature adulthood. We observed shifts in HSPC transcriptional states and differentiation trajectories over time. We identified age-specific gene expression patterns throughout human maturation and developed methods for identifying, prospectively purifying, and functionally validating age-specific HSC states. Together, our findings define the temporal maturation of human HSPCs and uncover principles applicable to age-biased blood diseases. SummarySingle cell RNA sequencing reveals that the mechanisms of human hematopoietic stem and progenitor cell (HSPC) fate commitment change over a lifetime from gestation to mature adulthood.

developmental biology↗

Single-cell analysis reveals mechanisms of plasticity of leukemia initiating cells

Leukemia initiating cells (LICs) fuel leukemic growth and spark relapse. Previously thought to be primitive and rare, the LIC state may actually be heterogeneous and dynamic, enabling evasion of therapies. Here, we use single-cell transcriptomics to track LIC multipotency within the cellular ontogeny of MLL-rearranged B-lymphoblastic leukemia (MLL-r B-ALL). Although we identify rare transcriptionally and phenotypically primitive LICs, we also observe LICs emerging from more differentiated populations with the capability to replenish the full leukemic cellular diversity. We find that activation of MYC-driven oxidative phosphorylation controls this process of facultative state conversion in LICs.

cancer biology↗