The various organogenic programs deployed during embryonic development rely on the precise expression of a multitude of genes in time and space. Identifying the cis-regulatory elements responsible for this tightly orchestrated regulation of gene expression is an essential step in understanding the genetic pathways involved in development. We describe a strategy to systematically identify tissue-specific cis-regulatory elements that share combinations of sequence motifs. Using heart development as an experimental framework, we employed a combination of Gibbs sampling and linear regression to build a classifier that identifies heart enhancers based on the presence and/or absence of various sequence features, including known and putative transcription factor (TF) binding specificities. In distinguishing heart enhancers from a large pool of random noncoding sequences, the performance of our classifier is vastly superior to four commonly used methods, with an accuracy reaching 92% in cross-validation. Furthermore, most of the binding specificities learned by our method resemble the specificities of TFs widely recognized as key players in heart development and differentiation, such as SRF, MEF2, ETS1, SMAD, and GATA. Using our classifier as a predictor, a genome-wide scan identified over 40,000 novel human heart enhancers. Although the classifier used no gene expression information, these novel enhancers are strongly associated with genes expressed in the heart. Finally, in vivo tests of our predictions in mouse and zebrafish achieved a validation rate of 62%, significantly higher than what is expected by chance. These results support the existence of underlying cis-regulatory codes dictating tissue-specific transcription in mammalian genomes and validate our enhancer classifier strategy as a method to uncover these regulatory codes.

BACKGROUND: Interstitial lung abnormalities (ILA) and interstitial lung disease (ILD) are seen in up to 60% of individuals with rheumatoid arthritis (RA), some of which will progress to have a significant impact on morbidity and mortality rates. Better characterization of progressive interstitial changes and identification of risk factors that are associated with progression may enable earlier intervention and improved outcomes. RESEARCH QUESTION: What are baseline characteristics associated with RA-ILD progression? STUDY DESIGN AND METHODS: We performed a retrospective study in which all clinically indicated CT chest scans in adult individuals with RA from 2014 to 2016 were evaluated for interstitial changes, and the data were further subdivided into ILA and ILD based on clinical record review. Progression was determined visually and subsequently semiquantified.RESULTS: Those individuals with a spectrum of interstitial changes (64 of 293) were older male smokers and less likely to be receiving biologics/small molecule disease-modifying antirheumatic drugs. Of 44% of the individuals with ILA, 46% had had chest CT scans performed for nonpulmonary indications. Of the 56 individuals with ILA/ILD with sequential CT scans, 38% had evidence of radiologic progression over 4.4 years; 29% of of individuals with ILA progressed. Risk factors for progressive ILA/ILD included a subpleural distribution and higher baseline involvement.INTERPRETATION: Of 293 individuals with RA with clinically indicated CT scans, interstitial changes were observed in 22%, one-half of whom had had a respiratory complaint at the time of imaging; radiologic progression was seen in 38%. Of individuals with progressive ILA, one-half had had baseline CT scans performed for nonpulmonary indications. Subpleural distribution and higher baseline ILA/ILD extent were risk factors associated with progression. Prospective longitudinal studies of RA-ILA are necessary.

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Aberrant activation of the three-amino-acid-loop extension (TALE) homeobox gene MEIS1 shortens the latency and accelerates the onset and progression of acute leukemia, yet the molecular mechanism underlying persistent activation of the MEIS1 gene in leukemia remains poorly understood. Here we used a combined comparative genomics analysis and an in vivo transgenic zebrafish assay to identify 6 regulatory DNA elements that are able to direct GFP expression in a spatiotemporal manner during zebrafish embryonic hematopoiesis. Analysis of chromatin characteristics and regulatory signatures suggest that many of these predicted elements are potential enhancers in mammalian hematopoiesis. Strikingly, one of the enhancer elements (E9) is a frequent integration site in retroviral induced mouse acute leukemia. The genomic region corresponding to enhancer E9 is differentially marked by H3K4 mono-methylation and H3K27 acetylation, hallmarks of active enhancers, in multiple leukemia cell lines. Decreased enrichment of these histone marks is associated with downregulation of MEIS1 expression during hematopoietic differentiation. Furthermore, MEIS1/HOXA9 transactivate this enhancer via a conserved binding motif in vitro, and participate in an autoregulatory loop that modulates MEIS1 expression in vivo. Our results suggest that an intronic enhancer regulates the expression of MEIS1 in hematopoiesis and contributes to its aberrant expression in acute leukemia.

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Objective:Pulmonary alveolar proteinosis (PAP) is a rare disease, characterized by the alveolar accumulation of surfactant, which is composed of proteins and lipids. PAP is caused by a deficit of macrophage activity, for which the main treatment is whole-lung lavage (WLL). We report the experience at a referral center for PAP in Brazil. Methods:This was a retrospective study involving patients with PAP followed between 2002 and 2016. We analyzed information regarding clinical history, diagnostic methods, treatments, and outcomes, as well as data on lung function, survival, and complications. Results:We evaluated 12 patients (8 of whom were women). The mean age was 41 ± 15 years. Most of the patients were diagnosed by means of BAL and transbronchial biopsy. The mean number of WLLs performed per patient was 2.8 ± 2.5. One third of the patients never underwent WLL. Four patients (33.3%) had associated infections (cryptococcosis, in 2; nocardiosis, in 1; and tuberculosis, in 1), and 2 (16.6%) died: 1 due to lepidic adenocarcinoma and 1 due to complications during anesthesia prior to WLL. When we compared baseline data with those obtained at the end of the follow-up period, there were no significant differences in the functional data, although there was a trend toward an increase in SpO2. The median follow-up period was 45 months (range, 1-184 months). The 5-year survival rate was 82%. Conclusions:To our knowledge, this is the largest case series of patients with PAP ever conducted in Brazil. The survival rate was similar to that found at other centers. For symptomatic, hypoxemic patients, the treatment of choice is still WLL. Precautions should be taken in order to avoid complications, especially opportunistic infections.

Introduction Sarcoidosis is a multi-systemic granulomatous disease of unknown etiology. Cardiac sarcoidosis (CS) has proven to be a clinically significant cause of unexplained ventricular dysfunction, atrioventricular block (AVB) and ventricular tachyarrhythmias (VT). Studies have suggested that clinically manifest cardiac involvement occurs in only 5% of patients with sarcoidosis. However, recent imaging studies have shown that cardiac involvement can be observed in up to 54.9% of patients with extracardiac sarcoidosis, mostly clinically silent, but that can eventually manifest into life-threatening arrhythmias. Purpose The purpose of this study was to evaluate the routine use of cardiac testing in patients with sarcoidosis. We aimed to evaluate the frequency with which clinical evaluation and cardiac testing are routinely utilized, the results of these tests, and how these results impacted downstream management. Methods This study was carried out in a tertiary hospital, assessing referred patients with suspected cardiac sarcoidosis. Clinically manifest CS was defined as the presence of ventricular systolic dysfunction, AVB or sustained VT. The cardiac involvement was evaluated with Late gadolinium-enhanced MRI and PET-CT with FDG. The diagnosis of cardiac sarcoidosis was performed using the criteria of the HRS. All patients had a biopsy with a histopathology suggestive of Sarcoidosis. Results Forty-one patients with sarcoidosis were evaluated. CS was confirmed in 46% (N=19), with exclusive cardiac involvement in 10% (N=2). The mean age was 53±9.6 years old and 53% (N=10) were female. Clinically manifest CS was present in 63% (N=12). The most prevalent initial cardiac manifestation was left ventricular dysfunction, in 58% (N=7), usually in the silent form (71%), with VT in 25% (N=3) and AVB in 17% (N=2). All patients with cardiac silent form had PET-CT with FDG or MRI suggestive of CS. The sensitivity of the MRI and PET-CT with FDG was 75% and 82%, respectively, while the concomitant performance of the two methods had a sensitivity of 100%, considering the HRS criteria as gold standard. Conclusion Cardiac involvement in patients with sarcoidosis is high and has important prognostic implications. With the enhancement of imaging tests, diagnosis of CS has significantly increased. PET-CT with FDG and MRI are very useful and effective in the evaluation of patients with CS.

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