SUMMARY Post-transcriptional adenosine-to-inosine RNA editing mediated by adenosine deaminase acting on RNA1 (ADAR1) promotes cancer progression and therapeutic resistance. However, ADAR1 editase-dependent mechanisms governing leukemia stem cell (LSC) generation have not been elucidated. In blast crisis chronic myeloid leukemia (BC CML), we show that increased JAK2 signaling and BCR-ABL1 amplification activate ADAR1. In a humanized BC CML mouse model, combined JAK2 and BCR-ABL1 inhibition prevents LSC self-renewal commensurate with ADAR1 downregulation. Lentiviral ADAR1 wild-type, but not an editing-defective ADAR1E912 mutant, induces self-renewal gene expression and impairs biogenesis of stem cell regulatory let-7 microRNAs. Combined RNA sequencing, qRT-PCR, CLIP-ADAR1, and pri-let-7 mutagenesis data suggest that ADAR1 promotes LSC generation via let-7 pri-microRNA editing and LIN28B upregulation. A small molecule tool compound antagonizes ADAR1’s effect on LSC self-renewal in stromal co-cultures and restores let-7 biogenesis. Thus, ADAR1 activation represents a unique therapeutic vulnerability in LSC with active JAK2 signaling.

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A project designed to foster the full and fair participation of girls in high‐school science classes addressed obstacles, both perceived and actual, to equal participation. In order to modify existing classroom techniques and environments, a Teacher Intervention Program was designed. By means of a workshop and periodic personal communications, teachers were sensitized to the importance of a stimulating, gender‐free learning environment. In addition, they were presented with a variety of methods and materials which had been shown to encourage girls in science. Twelve teachers, who were selected randomly, taught in diverse communities throughout one Midwestern state. The subjects tested were students in 24 general biology classes taught by the 12 teachers. Although both qualitative and quantitative measures were used during the research, only the quantitative results are discussed in this paper. Using ANOVA's, treatment group by student sex, a comparison of the mean scores was made for all students, as well as for all females and for all males. The results indicated that the experimental group, compared to the control group, had significantly higher mean scores on tests of attitudes toward science, perceptions of science, extracurricular science activities, and interest in a science‐related career.

American Indian and Alaska Native (AIAN) governments are sovereign entities with inherent authority to establish and administer public health programs within their communities and will be critical partners in national efforts to prepare for pandemic influenza. Within AIAN communities, some subpopulations will be particularly vulnerable during an influenza pandemic because of their underlying health conditions, whereas others will be at increased risk because of limited access to prevention or treatment interventions.We outline potential issues to consider in identifying and providing appropriate services for selected vulnerable populations within tribal communities. We also highlight pandemic influenza preparedness resources available to tribal leaders and their partners in state and local health departments, academia, community-based organizations, and the private sector.

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We developed an inquiry-based learning model to better stimulate undergraduate students’ cognitive development of exercise physiology laboratory concepts. The course core is the two independent research projects that students, working in small groups, complete during the last 9 wk of the semester. Student groups develop their own research question and hypothesis, design the experiment, collect and analyze the data, and report their findings to the rest of the class using presentation software. To help with success of the research projects, students are taken through a series of guided-inquiry laboratory activities during the initial 6 wk of the semester to develop laboratory skills and an understanding of the scientific process. Observations of student behaviors reflected a high level of enthusiasm and engagement in laboratory activities. Surveys, journal entries, and interviews indicated that students felt empowered by having ownership in their projects, which may be the key reason for the success of this model.

Formative research suggests that a human embryonic stem cellspecific alternative splicing gene regulatory network, which is repressed by Muscleblind-like (MBNL) RNA binding proteins, is involved in cell reprogramming. In this study, RNA sequencing, splice isoform-specific quantitative RT-PCR, lentiviral transduction, and in vivo humanized mouse model studies demonstrated that malignant reprogramming of progenitors into self-renewing blast crisis chronic myeloid leukemia stem cells (BC LSCs) was partially driven by decreased MBNL3. Lentiviral knockdown of MBNL3 resulted in reversion to an embryonic alternative splice isoform program typified by overexpression of CD44 transcript variant 3, containing variant exons 8-10, and BC LSC proliferation. Although isoform-specific lentiviral CD44v3 overexpression enhanced chronic phase chronic myeloid leukemia (CML) progenitor replating capacity, lentiviral shRNA knockdown abrogated these effects. Combined treatment with a humanized pan-CD44 monoclonal antibody and a breakpoint cluster region -ABL proto-oncogene 1, nonreceptor tyrosine kinase (BCR-ABL1) antagonist inhibited LSC maintenance in a niche-dependent manner. In summary, MBNL3 down-regulationrelated reversion to an embryonic alternative splicing program, typified by CD44v3 overexpression, represents a previously unidentified mechanism governing malignant progenitor reprogramming in malignant microenvironments and provides a pivotal opportunity for selective BC LSC detection and therapeutic elimination.S ince the discovery of induction of stem cell characteristics in somatic cells by enforced expression of four transcription factors (1, 2), human pluripotent stem cell research has provided key insights into human development. Comparative DNA and RNA sequencing (RNAseq) studies have revealed that humanspecific distal regulatory elements, RNA editing, and alternative splicing play key roles in human embryonic stem cell (hESC) self-renewal and cell fate determination (3-6). Several of the phosphoproteins regulated during differentiation are components of the posttranscriptional RNA modification machinery, including double-stranded RNA-specific adenosine deaminase (ADAR) and serine/arginine-rich splicing factor 7 (SFRS7), thereby highlighting the importance of RNA processing alterations in hESC cell fate determination (5). Another key stem cell regulatory protein, β-catenin, is involved in hESC pluripotency and in the transcriptional regulation of adhesion molecules such as CD44 (5).Increased CD44 expression and splice isoform switching have been linked to enhanced metastatic potential and a poor prognosis in several types of cancer (7,8). Alternative splicing of 9 out of 19 exons in human CD44 pre-mRNA results in expression of different transcript variants, leading to variation in the length and function of the extracellular domain [for National Center for Biotechnology Information (NCBI)-designated CD44 nomenclature, see SI Materials and Methods and Fig. 1E]. Binding of CD44 to stem cell niche-related extracellular ma...

Highlights d Inflammation-dependent APOBEC3C C-to-T deaminase fuels human HSPC expansion d C-to-T mutagenesis increases during human MPN pre-LSC evolution d Inflammation-induced ADAR1p150 isoform expression promotes hyperediting in pre-LSCs d JAK2/STAT3 inhibition and shRNA ADAR1 knockdown prevent STAT3 isoform switching in LSCs