The transcriptional landscape of hematopoietic stem cell ontogeny

Transcriptome analysis of adult hematopoietic stem cells (HSCs) and their progeny has revealed mechanisms of blood differentiation and leukemogenesis, but a similar analysis of HSC development is lacking. Here, we acquired the transcriptomes of developing HSCs purified from >2,500 murine embryos and adult mice. We found that embryonic hematopoietic elements clustered into three distinct transcriptional states characteristic of the definitive yolk sac, HSCs undergoing specification, and definitive HSCs. We applied a network-biology-based analysis to reconstruct the gene regulatory networks of sequential stages of HSC development and functionally validated candidate transcriptional regulators of HSC ontogeny by morpholino-mediated knockdown in zebrafish embryos. Moreover, we found that HSCs from in vitro differentiated embryonic stem cells closely resemble definitive HSCs, yet lack a Notch-signaling signature, likely accounting for their defective lymphopoiesis. Our analysis and web resource will enhance efforts to identify regulators of HSC ontogeny and facilitate the engineering of hematopoietic specification

Large intergenic non-coding RNA-RoR modulates reprogramming of human induced pluripotent stem cells

February 17, 2011The conversion of lineage-committed cells to induced pluripotent stem cells (iPSCs) by reprogramming is accompanied by a global remodeling of the epigenome[superscript 1, 2, 3, 4, 5], resulting in altered patterns of gene expression[superscript 2, 6, 7, 8, 9]. Here we characterize the transcriptional reorganization of large intergenic non-coding RNAs (lincRNAs)[superscript 10, 11] that occurs upon derivation of human iPSCs and identify numerous lincRNAs whose expression is linked to pluripotency. Among these, we defined ten lincRNAs whose expression was elevated in iPSCs compared with embryonic stem cells, suggesting that their activation may promote the emergence of iPSCs. Supporting this, our results indicate that these lincRNAs are direct targets of key pluripotency transcription factors. Using loss-of-function and gain-of-function approaches, we found that one such lincRNA (lincRNA-RoR) modulates reprogramming, thus providing a first demonstration for critical functions of lincRNAs in the derivation of pluripotent stem cells

Midbody accumulation through evasion of autophagy contributes to cellular reprogramming and tumorigenicity

The midbody is a singular organelle formed between daughter cells during cytokinesis and required for their final separation. Midbodies persist in cells long after division as midbody derivatives (MB(d)s), but their fate is unclear. Here we show that MB(d)s are inherited asymmetrically by the daughter cell with the older centrosome. They selectively accumulate in stem cells, induced pluripotent stem cells and potential cancer \u27stem cells\u27 in vivo and in vitro. MB(d) loss accompanies stem-cell differentiation, and involves autophagic degradation mediated by binding of the autophagic receptor NBR1 to the midbody protein CEP55. Differentiating cells and normal dividing cells do not accumulate MB(d)s and possess high autophagic activity. Stem cells and cancer cells accumulate MB(d)s by evading autophagosome encapsulation and exhibit low autophagic activity. MB(d) enrichment enhances reprogramming to induced pluripotent stem cells and increases the in vitro tumorigenicity of cancer cells. These results indicate unexpected roles for MB(d)s in stem cells and cancer \u27stem cells\u27

Surface antigen phenotypes of hematopoietic stem cells from embryos and murine embryonic stem cells

Surface antigens on hematopoietic stem cells (HSCs) enable prospective isolation and characterization. Here, we compare the cell-surface phenotype of hematopoietic repopulating cells from murine yolk sac, aorta-gonad-mesonephros, placenta, fetal liver, and bone marrow with that of HSCs derived from the in vitro differentiation of murine embryonic stem cells (ESC-HSCs). Whereas c-Kit marks all HSC populations, CD41, CD45, CD34, and CD150 were developmentally regulated: the earliest embryonic HSCs express CD41 and CD34 and lack CD45 and CD150, whereas more mature HSCs lack CD41 and CD34 and express CD45 and CD150. ESC-HSCs express CD41 and CD150, lack CD34, and are heterogeneous for CD45. Finally, although CD48 was absent from all in vivo HSCs examined, ESC-HSCs were heterogeneous for the expression of this molecule. This unique phenotype signifies a developmentally immature population of cells with features of both primitive and mature HSC. The prospective fractionation of ESC-HSCs will facilitate studies of HSC maturation essential for normal functional engraftment in irradiated adults

Telomere elongation in induced pluripotent stem cells from dyskeratosis congenita patients

10.1038/nature08792Nature4647286292-296NATU

Long-term Effects of Multimodal Treatment on Adult Attention-Deficit/Hyperactivity Disorder Symptoms Follow-up Analysis of the COMPAS Trial

IMPORTANCE Knowledge about the long-term effects of multimodal treatment in adult attention-deficit/hyperactivity disorder (ADHD) is much needed. OBJECTIVE To evaluate the long-term efficacy of multimodal treatment for adult ADHD. DESIGN, SETTING, AND PARTICIPANTS This observer-masked, 1.5-year follow-up of the Comparison of Methylphenidate and Psychotherapy in Adult ADHD Study (COMPAS), a prospective, multicenter randomized clinical trial, compared cognitive behavioral group psychotherapy (GPT) with individual clinical management (CM) and methylphenidate (MPH) with placebo (2 x 2 factorial design). Recruitment started January 2007 and ended August 2010, and treatments were finalized in August 2011 with follow-up through March 2013. Overall, 433 adults with ADHD participated in the trial, and 256 (59.1%) participated in the follow-up assessment. Analysis began in November 2013 and was completed in February 2018. INTERVENTIONS After 1-year treatment with GPT or CM and MPH or placebo, no further treatment restrictions were imposed. MAIN OUTCOMES AND MEASURES The primary outcome was change in the observer-masked ADHD Index of Conners Adult ADHD Rating Scale score from baseline to follow-up. Secondary outcomes included further ADHD rating scale scores, observer-masked ratings of the Clinical Global Impression scale, and self-ratings of depression on the Beck Depression Inventory. RESULTS At follow-up, 256 of 433 randomized patients (baseline measured in 419 individuals) participated. Of the 256 patients participating in follow-up, the observer-masked ADHD Index of Conners Adult ADHD Rating Scale score was assessed for 251; the mean (SD) baseline age was 36.3 (10.1) years; 125 patients (49.8%) were men; and the sample was well-balanced with respect to prior randomization (GPT and MPH: 64 of 107; GPT and placebo: 67 of 109; CM and MPH: 70 of 110; and CM and placebo: 55 of 107). At baseline, the all-group mean ADHD Index of Conners Adult ADHD Rating Scale score was 20.6, which improved to adjusted means of 14.2 for the GPT arm and 14.7 for the CM arm at follow-up with no significant difference between groups (difference, -0.5; 95% CI, -1.9 to 0.9; P=.48). The adjusted mean decreased to 13.8 for the MPH arm and 15.2 for the placebo arm (difference, -1.4; 95% CI, -2.8 to -0.1; P=.04). As in the core study, MPH was associated with a larger reduction in symptoms than placebo at follow-up. These results remained unchanged when accounting for MPH intake at follow-up. Compared with participants in the CM arm, patients who participated in group psychotherapy were associated with less severe symptoms as measured by the self-reported ADHD Symptoms Total Score according to the Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition) (DSM-IV) of Conners Adult ADHD Rating Scale (AMD, -2.1; 95% CI, -4.2 to -0.1; P=.04) and in the subscale of reducing pure hyperactive symptoms, measured via the Diagnostic Checklist for the diagnosis of ADHD in adults (AMD, -1.3; 95% CI, -2.8 to 0.1; P=.08). Regarding the Clinical Global Impression scale assessment of effectiveness, the difference between GPT and CM remained significant at follow-up (odds ratio, 1.63; 95% CI, 1.03-2.59; P=.04). No differences were found for any comparison concerning depression as measured with the Beck Depression Inventory. CONCLUSIONS AND RELEVANCE Results from COMPAS demonstrate a maintained improvement in ADHD symptoms for adults 1.5 years after the end of a 52-week controlled multimodal treatment period. The results indicate that MPH treatment combined with GPT or CM provides a benefit lasting 1.5 years. Confirming the results of the core study, GPT was not associated with better results regarding the primary outcome compared with CM. TRIAL REGISTRATION isrctn.org Identifier: ISRCTN5409620