名古屋大学博士学位論文 学位の種類:博士(医療技術学) (課程) 学位授与年月日:平成20年3月25日

Acute myeloid leukemia (AML) is a clonal neoplastic disorder organized as a cellular hierarchy, with the self-renewing leukemia stem cell (LSC) at the apex. Recurrent mutations in transcription factors (TF) and epigenetic regulators suggest that AML is driven by aberrant transcriptional circuits, but these circuits have not been fully defined in an LSC model. To study transcriptional mechanisms relevant to leukemogenesis in vivo, we generated a murine serial transplantation model of MLL-AF9-driven, myelomonocytic leukemia with genetically- and phenotypically-defined LSCs. Using this model, we pursued two related lines of investigation. First, we performed an in vivo RNA interference (RNAi) screen to identify transcription factors required for LSC function. This screen highlighted the circadian rhythm TFs, Clock and Bmal1, as genes essential for the survival of murine leukemia cells, and we validated this finding with CRISPR/Cas-based genome editing and knockdown studies in AML cell lines. Utilizing luciferase reporter mice to track expression of the circadian target gene Per2, we demonstrated that both leukemic and normal hematopoietic cells have the capacity for oscillating, circadian-dependent gene expression. Importantly, using murine knockout models, we found that normal hematopoietic stem and progenitor cells (HSPC), in contrast to leukemia cells, do not depend on Bmal1. We further demonstrated that selective depletion of LSCs following circadian perturbation is mediated through enhanced myeloid differentiation. ChIP-Seq studies revealed that the circadian rhythm network is integrally connected to the LSC self-renewal circuitry and highlighted putative Clock/Bmal1 targets in leukemia, providing a mechanistic basis for our findings. Second, we performed a functional and genomic characterization of our MLL-AF9 serial transplantation model to explore mechanisms of disease evolution and clonal selection in AML. Limiting dilution studies demonstrated that serial transplantation results in a reduction in disease latency, dramatic enrichment of leukemia-initiating cells (LIC), and reconfiguration of the LSC hierarchy. While mutations in known AML-associated genes were not linked to disease progression, RNA-sequencing (RNA-Seq) demonstrated that the increase in LIC frequency in serially transplanted leukemias is driven by changes in cell cycle and differentiation. In aggregate, these studies offer insights into the biological mechanisms regulating LSC self-renewal and disease evolution in AML.

Tyrimo objektas: miego ir paros ciklo įtaka atminčiai, sveikiems asmenims. Darbo tikslas: nustatyti kaip miegas ir paros ciklas veikia sveikų žmonių atmintį. Darbo uždaviniai: 1. Išsiaiškinti, kaip vidinės kūno temperatūros pokyčiai veikia nuotaiką ir mieguistumą. 2. Ištirti, kaip paros ciklo metu kinta atminties aktyvumas. 3. Palyginti atminties aktyvumą po išsimiegotos nakties su atminties aktyvumu po bemiegės nakties. Tyrimo hipotezės: vidinės kūno temperatūros svyravimai atspindi atminties aktyvumą. Tyrimo metodai: Mokslinės literatūros analizė. Empirinis tyrimas naudojat kompiuterinę testų programą ANAM4. Statistinė duomenų analizė. Išvados: 1. Vidinė kūno temperatūra veikia, mieguistumą ir nuotaiką. Kai nakties metu vidinė kūno temperatūra krenta, padidėja mieguistumas ir pablogėja nuotaika, o kai dienos metu vidinė kūno temperatūra kyla, mažėja mieguistumas ir pagerėja nuotaika. 2. Vidinės kūno temperatūros svyravimai atspindi darbinės atminties aktyvumo svyravimus, kai reikia atsiminti išmoktus objektus. O atliekant matematinius skaičiavimus ir erdvinio suvokimo užduotis, atmintis aktyvumo svyravimai nesutapo su vidinės kūno temperatūros svyravimais. 3. Atmintis aktyvumas yra geresnis dieną po išsimiegotos nakties, lyginant su diena po bemiegės nakties. / The object of research: sleep and circadian rhythm effects on healthy people memory. The aim of research: to find out how sleep and circadian rhythm effects memory in healthy The goals of research: 1. Find out, how core body temperature effects mood and sleepiness. 2. Determine, how memory activity changes in circadian rhythm. 3. Compare memory activity after sleep night with memory activity after sleepless. Hypothesis: core body temperature reflects fluctuations in memory activity. Research methods: Scientific literature analysis. Empiric research using computer cognitive tests program ANAM4. Statistical data analysis. Conclusions: 1. Core body temperature affects sleepiness and mood. When at night time core body temperature decreases, sleepiness increase and mood impairs, and when at day time core body temperature increases, sleepiness decreases and mood improves. 2. Core body temperature fluctuations reflects memory activity, when need to recognize learned objects. In mathematical computation and spatial processing, memory activity does not match with core body temperature fluctuations. 3. Memory activity is higher during day after sleep night, comparing with memory activity after sleepless night.

Periodic cues, including scheduled exercise, social interactions, sleep habits, and feeding time, have been shown to alter the circadian system. A disruption in circadian rhythms has been shown to have negative effects on health. Frequent skin temperature measures have been shown to be a valid method of assessing circadian rhythm parameters. The purpose of this study was to determine group mean differences in temperature amplitude, stability and lag measures among groups of young men of varying (optimal, fair and poor) adiposities. The strength of the association among the temperatures parameters and measures of body composition, physical fitness and activity, nutritional intake, lipid concentrations, and sleep were also examined. Findings indicated that men with poor adiposity had significantly lower mean amplitude and stability than the optimal or fair groups; with no significant differences in lag among the groups. Factors including physical fitness, physical activity and late night eating contributed to the variance in amplitude; physical activity, time spent in moderate to vigorous activity, late night snacking, and fat mass to stability; and sleep hours and lipid ratios to lag. These findings contribute to the identification of targeted intervention strategies that may improve the circadian synchrony and health of young men.

No description available.

Thesis (Ph. D.)--University of Virginia, 2008. / Includes bibliographical references. Also available in electronic form as viewed 2/16/2009.

Diss. (sammanfattning) Stockholm : Karol. inst., 2006. / Härtill 5 uppsatser.

Thesis (Ph. D.)--University of Washington, 2008. / Vita. Includes bibliographical references (leaves 110-127).

Thesis (Ph. D.) -- University of Texas Southwestern Medical Center at Dallas, 2004. / Vita. Bibliography: 97-109.

No description available.