Aberrant chromatin landscape following loss of the H3.3 chaperone Daxx in haematopoietic precursors leads to Pu.1-mediated neutrophilia and inflammation

Defective silencing of retrotransposable elements has been linked to inflammageing, cancer and autoimmune diseases. However, the underlying mechanisms are only partially understood. Here we implicate the histone H3.3 chaperone Daxx, a retrotransposable element repressor inactivated in myeloid leukaemia and other neoplasms, in protection from inflammatory disease. Loss of Daxx alters the chromatin landscape, H3.3 distribution and histone marks of haematopoietic progenitors, leading to engagement of a Pu.1-dependent transcriptional programme for myelopoiesis at the expense of B-cell differentiation. This causes neutrophilia and inflammation, predisposing mice to develop an autoinflammatory skin disease. While these molecular and phenotypic perturbations are in part reverted in animals lacking both Pu.1 and Daxx, haematopoietic progenitors in these mice show unique chromatin and transcriptome alterations, suggesting an interaction between these two pathways. Overall, our findings implicate retrotransposable element silencing in haematopoiesis and suggest a cross-talk between the H3.3 loading machinery and the pioneer transcription factor Pu.1

Mir142 loss unlocks IDH2R140-dependent leukemogenesis through antagonistic regulation of HOX genes

AML is a genetically heterogeneous disease and understanding how different co-occurring mutations cooperate to drive leukemogenesis will be crucial for improving diagnostic and therapeutic options for patients. MIR142 mutations have been recurrently detected in IDH-mutated AML samples. Here, we have used a mouse model to investigate the interaction between these two mutations and demonstrate a striking synergy between Mir142 loss-of-function and IDH2R140Q, with only recipients of double mutant cells succumbing to leukemia. Transcriptomic analysis of the non-leukemic single and leukemic double mutant progenitors, isolated from these mice, suggested a novel mechanism of cooperation whereby Mir142 loss-of-function counteracts aberrant silencing of Hoxa cluster genes by IDH2R140Q. Our analysis suggests that IDH2R140Q is an incoherent oncogene, with both positive and negative impacts on leukemogenesis, which requires the action of cooperating mutations to alleviate repression of Hoxa genes in order to advance to leukemia. This model, therefore, provides a compelling rationale for understanding how different mutations cooperate to drive leukemogenesis and the context-dependent effects of oncogenic mutations

Informed consent in Sri Lanka: A survey among ethics committee members

<p>Abstract</p> <p>Background</p> <p>Approval of the research proposal by an ethical review committee from both sponsoring and host countries is a generally agreed requirement in externally sponsored research.</p> <p>However, capacity for ethics review is not universal. Aim of this study was to identify opinions and views of the members serving in ethical review and ethics committees in Sri Lanka on informed consent, essential components in the information leaflet and the consent form.</p> <p>Methods</p> <p>We obtained ethical approval from UK and Sri Lanka. A series of consensus generation meetings on the protocol were conducted. A task oriented interview guide was developed. The interview was based on open-ended questionnaire. Then the participants were given a WHO checklist on informed consent and requested to rate the items on a three point scale ranging from extremely important to not important.</p> <p>Results</p> <p>Twenty-nine members from ethics committees participated. Majority of participants (23), believed a copy of the information leaflet and consent form, should accompany research proposal. Opinions about the items that should be included in the information leaflets varied. Participants identified 18 criteria as requirements in the information leaflet and 19 for the consent form.</p> <p>The majority, 20 (69%), believed that all research need ethical approval but identified limited human resource, time and inadequate capacity as constraints. Fifteen (52%) believed that written consent is not required for all research. Verbal consent emerged as an alternative to written consent. The majority of participants rated all components of the WHO checklist as important.</p> <p>Conclusion</p> <p>The number of themes generated for the consent form (N = 18) is as many as for the information leaflet (N = 19) and had several overlaps. This suggests that the consent form should be itemized to reflect the contents covered in the information leaflet. The participants' opinion on components of the information leaflets and consent forms proved to be similar with WHO checklist on informed consent.</p

Ethics Review Committee approval and informed consent: an analysis of biomedical publications originating from Sri Lanka

<p>Abstract</p> <p>Background</p> <p>International guidelines on research have focused on protecting research participants. Ethical Research Committee (ERC) approval and informed consent are the cornerstones. Externally sponsored research requires approval through ethical review in both the host and the sponsoring country. This study aimed to determine to what extent ERC approval and informed consent procedures are documented in locally and internationally published human subject research carried out in Sri Lanka.</p> <p>Methods</p> <p>We obtained ERC approval in Sri Lanka and the United Kingdom. Theses from 1985 to 2005 available at the Postgraduate Institute of Medicine (PGIM) library affiliated to the University of Colombo were scrutinised using checklists agreed in consultation with senior research collaborators. A Medline search was carried out with MeSH major and minor heading 'Sri Lanka' as the search term for international publications originating in Sri Lanka during 1999 to 2004. All research publications from CMJ during 1999 to 2005 were also scrutinized.</p> <p>Results</p> <p>Of 291 theses, 34% documented ERC approvals and 61% documented obtaining consent. From the international journal survey, 250 publications originated from Sri Lanka of which only 79 full text original research publications could be accessed electronically. Of these 38% documented ERC approval and 39% documented obtaining consent. In the Ceylon Medical Journal 36% documented ERC approval and 37% documented obtaining consent.</p> <p>Conclusion</p> <p>Only one third of the publications scrutinized recorded ERC approval and procurement of informed consent. However, there is a positive trend in documenting these ethical requirements in local postgraduate research and in the local medical journal.</p

Mir142 loss unlocks IDH2^R140-dependent leukemogenesis through antagonistic regulation of HOX genes

AML is a genetically heterogeneous disease and understanding how different co-occurring mutations cooperate to drive leukemogenesis will be crucial for improving diagnostic and therapeutic options for patients. MIR142 mutations have been recurrently detected in IDH-mutated AML samples. Here, we have used a mouse model to investigate the interaction between these two mutations and demonstrate a striking synergy between Mir142 loss-of-function and IDH2R140Q, with only recipients of double mutant cells succumbing to leukemia. Transcriptomic analysis of the non-leukemic single and leukemic double mutant progenitors, isolated from these mice, suggested a novel mechanism of cooperation whereby Mir142 loss-of-function counteracts aberrant silencing of Hoxa cluster genes by IDH2R140Q. Our analysis suggests that IDH2R140Q is an incoherent oncogene, with both positive and negative impacts on leukemogenesis, which requires the action of cooperating mutations to alleviate repression of Hoxa genes in order to advance to leukemia. This model, therefore, provides a compelling rationale for understanding how different mutations cooperate to drive leukemogenesis and the context-dependent effects of oncogenic mutations

Cytokine expression by Alveolar Macrophages 24 hours after stimulation with increasing doses of WTC-PM_2.5 and WTC-PM_10–53 in µg/ml.

<p>All cytokines with a ≥2-fold induction of PM_10–53/PM_2.5 at each dose are shown. All graphs show mean ± SEM of cytokine, p<0.01 for all comparisons between PM_10–53 and PM_2.5 by Wilcoxon Matched Pairs Signed Rank Test. Panel A) GM-CSF B) IL-6 C) IL-10 D) TNF-α. N = 14 for WTC-PM_2.5 and WTC-PM_10–53 at 10 µg/mL; N = 15 for all other exposures.</p

Comparison of WTC Dust Size on Macrophage Inflammatory Cytokine Release <em>In vivo</em> and <em>In vitro</em>

<div><h3>Background</h3><p>The WTC collapse exposed over 300,000 people to high concentrations of WTC-PM; particulates up to ∼50 mm were recovered from rescue workers’ lungs. Elevated MDC and GM-CSF independently predicted subsequent lung injury in WTC-PM-exposed workers. Our hypotheses are that components of WTC dust strongly induce GM-CSF and MDC in AM; and that these two risk factors are in separate inflammatory pathways.</p> <h3>Methodology/Principal Findings</h3><p>Normal adherent AM from 15 subjects without WTC-exposure were incubated in media alone, LPS 40 ng/mL, or suspensions of WTC-PM_10–53 or WTC-PM_2.5 at concentrations of 10, 50 or 100 µg/mL for 24 hours; supernatants assayed for 39 chemokines/cytokines. In addition, sera from WTC-exposed subjects who developed lung injury were assayed for the same cytokines. In the <em>in vitro</em> studies, cytokines formed two clusters with GM-CSF and MDC as a result of PM_10–53 and PM_2.5. GM-CSF clustered with IL-6 and IL-12(p70) at baseline, after exposure to WTC-PM_10–53 and in sera of WTC dust-exposed subjects (n = 70) with WTC lung injury. Similarly, MDC clustered with GRO and MCP-1. WTC-PM_10–53 consistently induced more cytokine release than WTC-PM_2.5 at 100 µg/mL. Individual baseline expression correlated with WTC-PM-induced GM-CSF and MDC.</p> <h3>Conclusions</h3><p>WTC-PM_10–53 induced a stronger inflammatory response by human AM than WTC-PM_2.5. This large particle exposure may have contributed to the high incidence of lung injury in those exposed to particles at the WTC site. GM-CSF and MDC consistently cluster separately, suggesting a role for differential cytokine release in WTC-PM injury. Subject-specific response to WTC-PM may underlie individual susceptibility to lung injury after irritant dust exposure.</p> </div

Hierarchical Clustering of Chemokine and Cytokine Expression in in vitro and in vivo exposures to WTC-PM.

<p>Clustering was performed by log-transformed data and Spearman Correlation, with average linkage. GM-CSF is highlighted in grey, and MDC is highlighted in the clear box. Shown is the clustering of chemokines and cytokines that were consistently segregated in the <i>in vitro</i> and <i>in vivo</i> studies. GM-CSF and MDC are in separate clusters. <b>A</b>) The 22 analytes with median baseline expression levels above the LOD were clustered. Two separate clusters were identified, each containing 11 analytes. <i>In vitro</i>, baseline <b>B</b>) WTC-PM_2.5 100 µg/mL <i>in vitro</i>. <b>C</b>) WTC-PM_10–53 100 µg/mL in vitro. <b>D</b>) Serum from WTC-exposed patients with WTC-Lung Injury. E) Serum from the WTC-Exposed control population with normal lung function.</p

Spearman’s Rank Order Correlation Coefficients Relative to Unstimulated Baseline.

<p>Particulate Matter (PM) in µg/mL;</p>*<p>p<0.05.</p>**<p>p<0.01.</p

BAL Differential and Demographics of Study Population.

<p><b>Abbreviations:</b> M-Macrophages; L-Lymphocytes; N-Neutrophils; E-Eosinophils; M-Male; F-Female; AA-African American; C-Caucasian; Y-Yes, Ever-Smoker; N-No, Never-Smoker.</p>*<p>Differential rounded to whole number, Cumulative expressed as Mean (SD).</p>**<p>Cumulative expressed as %(N): Male/Caucasian/Ever-Smoker.</p>#<p>Cumulative expressed as Mean (SD).</p