BMP2 commitment to the osteogenic lineage involves activation of Runx2 by DLX3 and a homeodomain transcriptional network

Several homeodomain (HD) proteins are critical for skeletal patterning and respond directly to BMP2 as an early step in bone formation. RUNX2, the earliest transcription factor proven essential for commitment to osteoblastogenesis, is also expressed in response to BMP2. However, there is a gap in our knowledge of the regulatory cascade from BMP2 signaling to the onset of osteogenesis. Here we show that BMP2 induces DLX3, a homeodomain protein that activates Runx2 gene transcription. Small interfering RNA knockdown studies in osteoblasts validate that DLX3 is a potent regulator of Runx2. Furthermore in Runx2 null cells, DLX3 forced expression suffices to induce transcription of Runx2, osteocalcin, and alkaline phosphatase genes, thus defining DLX3 as an osteogenic regulator independent of RUNX2. Our studies further show regulation of the Runx2 gene by several homeodomain proteins: MSX2 and CDP/cut repress whereas DLX3 and DLX5 activate endogenous Runx2 expression and promoter activity in non-osseous cells and osteoblasts. These HD proteins exhibit distinct temporal expression profiles during osteoblast differentiation as well as selective association with Runx2 chromatin that is related to Runx2 transcriptional activity and recruitment of RNA polymerase II. Runx2 promoter mutagenesis shows that multiple HD elements control expression of Runx2 in relation to the stages of osteoblast maturation. Our studies establish mechanisms for commitment to the osteogenic lineage directly through BMP2 induction of HD proteins DLX3 and DLX5 that activate Runx2, thus delineating a transcriptional regulatory pathway mediating osteoblast differentiation. We propose that the three homeodomain proteins MSX2, DLX3, and DLX5 provide a key series of molecular switches that regulate expression of Runx2 throughout bone formation. <br/

Pan-Src Family Kinase Inhibitors Replace Sox2 during the Direct Reprogramming of Somatic Cells

Small molecules do the job: Somatic cells are reprogrammed into iPS cells upon ectopic expression of Oct4, Sox2, Klf4 and c-Myc. Application of a cell-based, high-throughput chemical screen led to the identification of Src family kinase (SFK) inhibitors as chemical replacements for retroviral Sox2 delivery. These compounds are used to study the mechanisms underlying direct reprogramming and may ultimately help to bring iPS cell technology one step closer to clinical application.National Institutes of Health (U.S.) (Grant HD 045022)National Institutes of Health (U.S.) (Grant 5 R37A084198

Nurses' experiences of psychiatric patients with HIV/AIDS: A study conducted in a psychiatric hospital in the Western Cape

Bibliography: leaves 91-95.This study aims to explore the experiences of nursing staff who provide treatment and care for psychiatric patients with HIV/AIDS. The study was conducted with a view to understanding the psychological impact of caring for such patients, the additional stressors which may arise as a result of this and how these are dealt with. It was also intended to assist with identifying the needs that staff may have in order to cope with the demands of their work. Semi-structured interviews were conducted with nine nurses working in the female admission ward of a Western Cape psychiatric hospital. The interview material was analysed to identify common themes which occurred across the interviews concerning participants' experiences, their difficulties and their feelings regarding their work with HIV/AIDS patients. A number of theoretical perspectives were used in analysing and discussing the material, including theories of HIV/AIDS related occupational stress; psychodynamic theory and literature from the field of medical anthropology.The study found that overall, nursing psychiatric patients with HIV/AIDS was experienced as difficult and stressful by participants, and evoked strong emotions of fear and anxiety. The experience of stress in psychiatric HIV/AIDS care was strongly associated with the nature of the work and the anxieties evoked by nursing patients with a terminal, contagious disease. However, the difficulties experienced by participants also appeared to be related to the context of their working environment, and to extend beyond this to the broader social influences of family and community life. The absence of effective support and acknowledgement of these difficulties has resulted in physical symptoms of bum out and the adoption of individual and collective defences in an attempt to cope with the enormous personal and professional challenges of their work

Musashi-2 controls cell fate, lineage bias, and TGF-β signaling in HSCs

Hematopoietic stem cells (HSCs) are maintained through the regulation of symmetric and asymmetric cell division. We report that conditional ablation of the RNA-binding protein Msi2 results in a failure of HSC maintenance and engraftment caused by a loss of quiescence and increased commitment divisions. Contrary to previous studies, we found that these phenotypes were independent of Numb. Global transcriptome profiling and RNA target analysis uncovered Msi2 interactions at multiple nodes within pathways that govern RNA translation, stem cell function, and TGF-β signaling. Msi2-null HSCs are insensitive to TGF-β–mediated expansion and have decreased signaling output, resulting in a loss of myeloid-restricted HSCs and myeloid reconstitution. Thus, Msi2 is an important regulator of the HSC translatome and balances HSC homeostasis and lineage bias

The Impact of a Teacher’s Implementation of the Writing Process on Student Performance

Writing is a crucial skill that students need to consistently practice throughout their educational experiences. However, new technologies, such as AI, are beginning to create worries amongst educators regarding a shift from writing as an opportunity to grow towards writing as solely a product to be graded. This emerging mindset led to the development of the research question: how does a teacher’s implementation of the writing process impact a student’s performance? A review of the literature was conducted to analyze topics related to the problems that led to the development of the research question. This review consisted of three categories of research: self-efficacy, role of the teacher, and revision strategies. After the review of the literature, I conducted a four-week study centered around the implementation of the writing process in a twelfth grade Honors English IV class. The participants were nine twelfth grade students. Four data sources were used: rubric scores on a final written product, teacher feedback, student reflection on the writing process, and teacher fieldnotes. The findings of the four-week study resulted in three themes: students struggle in crafting a clear and concise thesis statement in the initial stages of the writing process, the impacts of individualized feedback are demonstrated through stronger revisions being made after receiving feedback, and student understanding of the writing process grew as a result of prioritizing revision throughout the writing process. The study findings suggest that individualized feedback provided throughout the writing process positively impacted student writing, and that students improve their understanding of the writing process as a result of prioritizing revision throughout the writing process

Paper Session III-A - America\u27s Space Transportation System for the 1990\u27s and Beyond

NASA and the nation are again at a point of decision concerning the future direction of space exploration and space exploitation. Many new initiatives have been proposed for future exploration and colonization of the solar system, including an outpost on the moon and, eventually, a permanent Martian base. The transportation system required to implement these bold, new initiatives must be a powerful one—able to explore new frontiers, transport large amounts of cargo, and guarantee safety and reliability well into the next century. NASA must now decide how to implement these goals. Through ongoing NASA upgrades and evolution programs, the current transportation system, the Space Shuttle, can evolve to meet the mission requirements of the 1990s and beyond. The broad scope of these evolutionary studies encompasses both the Shuttle and Shuttle-derived vehicles, such as Shuttle-C. Shuttle evolution delays the requirement for a new lowearth- orbit space transportation system well into the next century, when significantly new mission requirements and/or the development of new enabling technology may justify a new system. This paper discusses the ongoing programs sponsored by NASA and Rockwell that will evolve the Shuttle into the space transportation system for the future. These programs include NASA\u27s Assured Shuttle Availability Program, which will develop and implement cost-effective Shuttle improvements, and Rockwejl\u27s IR&D projects, which are targeted at avoiding Shuttle system obsolescence and improving Shuttle safety, operations cost, and performance margin

Rb regulates fate choice and lineage commitment in vivo

February 1, 2011Mutation of the retinoblastoma gene (RB1) tumour suppressor occurs in one-third of all human tumours and is particularly associated with retinoblastoma and osteosarcoma[superscript 1]. Numerous functions have been ascribed to the product of the human RB1 gene, the retinoblastoma protein (pRb). The best known is pRb’s ability to promote cell-cycle exit through inhibition of the E2F transcription factors and the transcriptional repression of genes encoding cell-cycle regulators[superscript 1]. In addition, pRb has been shown in vitro to regulate several transcription factors that are master differentiation inducers[superscript 2]. Depending on the differentiation factor and cellular context, pRb can either suppress or promote their transcriptional activity. For example, pRb binds to Runx2 and potentiates its ability to promote osteogenic differentiation in vitro[superscript 3]. In contrast, pRb acts with E2F to suppress peroxisome proliferator-activated receptor γ subunit (PPAR-γ), the master activator of adipogenesis[superscript 4, 5]. Because osteoblasts and adipocytes can both arise from mesenchymal stem cells, these observations suggest that pRb might play a role in the choice between these two fates. However, so far, there is no evidence for this in vivo. Here we use mouse models to address this hypothesis in mesenchymal tissue development and tumorigenesis. Our data show that Rb status plays a key role in establishing fate choice between bone and brown adipose tissue in vivo.National Cancer Institute (U.S.) (Grant)National Institutes of Health (U.S.) (Grant

Specific detection of OCT3/4 isoform A/B/B1 expression in solid (germ cell) tumours and cell lines: Confirmation of OCT3/4 specificity for germ cell tumours

Background: OCT3/4 (POU5F1) is an established diagnostic immunohistochemical marker for specific histological variants of human malignant germ cell tumours (GCTs), including the seminomatous types and the stem cell component of non-seminomas, known as embryonal carcinoma. OCT3/4 is crucial for the regulation of pluripotency and the self-renewal of normal embryonic stem-and germ cells. Detection of expression of this transcription factor is complicated by the existence of multiple pseudogenes and isoforms. Various claims have been made about OCT3/4 expression in non-GCTs, possibly related to using nonspecific detection methods. False-positive findings undermine the applicability of OCT3/4 as a specific diagnostic tool in a clinical setting. In addition, false-positive findings could result in misinterpretation of pluripotency regulation in solid somatic cancers and their stem cells. Of the three identified isoforms-OCT4A, OCT4B and OCT4B1-only OCT4A proved to regulate pluripotency. Up until now, no convincing nuclear OCT4A protein expression has been shown in somatic cancers or tissues. Methods: This study investigates expression of the various OCT3/4 isoforms in GCTs (both differentiated and undifferentiated) and somatic (non-germ cell) cancers, including representative cell lines and xenografts. Results: Using specific methods, OCT4A and OCT4B1 are shown to be preferentially expressed in undifferentiated GCTs. The OCT4B variant shows no difference in expression between GCTs (either differentiated or undifferentiated) and somatic cancers. In spite of the presence of OCT4A mRNA in somatic cancer-derived cell lines, no OCT3/4