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BACKGROUND: Inhaled treprostinil (iTre) is the only treatment approved for pulmonary hypertension due to interstitial lung disease (PH-ILD) to improve exercise capacity. This post hoc analysis evaluated clinical worsening and PH-ILD exacerbations from the 16-week INCREASE study and change in 6-minute walking distance (6MWD) in the INCREASE open-label extension (OLE) in patients with less severe haemodynamics. METHODS: Patients were stratified by baseline pulmonary vascular resistance (PVR) of <4 Wood units (WU) versus ≥4 WU and <5 WU versus ≥5 WU. Exacerbations of underlying lung disease, clinical worsening and change in N-terminal prohormone of brain natriuretic peptide (NT-proBNP) in INCREASE were evaluated. For the OLE, patients previously assigned to placebo were considered to have a 16-week treatment delay. 6MWD and clinical events in the OLE were evaluated by PVR subgroup. RESULTS: Of the 326 patients enrolled in INCREASE, patients with less severe haemodynamics receiving iTre had fewer exacerbations of underlying lung disease and clinical worsening events. This was supported by the Bayesian analysis of the risk of disease progression (HR<1), and significant decreases in NT-proBNP levels. In the OLE, patients without a treatment delay had improved exercise capacity after 1-year compared with those with a 16-week treatment delay (22.1 m vs -10.3 m). Patients with a PVR of ≤5 WU without a treatment delay had a change of 5.5 m compared with -8.2 m for those with a treatment delay. Patients without a treatment delay had a prolonged time to hospitalisation, lung disease exacerbation and death. CONCLUSION: Treatment with iTre led to consistent benefits in clinical outcomes in patients with PH-ILD and less severe haemodynamics. Earlier treatment in less severe PH-ILD may lead to better exercise capacity long-term, however, the subgroup analyses in this post hoc study were underpowered and confirmation of these findings is needed.
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Epoprostenol , Hipertensión Pulmonar , Enfermedades Pulmonares Intersticiales , Humanos , Teorema de Bayes , Epoprostenol/análogos & derivados , Hemodinámica , Hipertensión Pulmonar/tratamiento farmacológico , Hipertensión Pulmonar/etiología , Enfermedades Pulmonares Intersticiales/complicaciones , Enfermedades Pulmonares Intersticiales/tratamiento farmacológico , Ensayos Clínicos Controlados Aleatorios como AsuntoRESUMEN
Pulmonary hypertension currently has minimal guidelines for outpatient disease management. Congestive heart failure studies, however, have shown effectiveness of disease management plans in reducing all-cause mortality and all-cause and congestive heart failure-related hospital readmissions. Heart failure exacerbation is a common reason for readmission in both pulmonary hypertension and congestive heart failure. Our aim was to review individual studies and comprehensive meta-analyses to identify effective congestive heart failure interventions that can be used to develop similar disease management plans for pulmonary hypertension. A comprehensive literature review from 1993 to 2019 included original articles, systematic reviews, and meta-analyses. We reviewed topics of outpatient congestive heart failure interventions to decrease congestive heart failure mortality and readmission and patient management strategies in congestive heart failure. The most studied interventions included case management, multidisciplinary intervention, structured telephone strategy, and tele-monitoring. Case management showed decreased all-cause mortality at 12 months, all-cause readmission at 12 months, and congestive heart failure readmission at 6 and 12 months. Multidisciplinary intervention resulted in decreased all-cause readmission and congestive heart failure readmission. There was some discrepancy on effectiveness of tele-monitoring programs in individual studies; however, meta-analyses suggest tele-monitoring provided reduced all-cause mortality and risk of congestive heart failure hospitalization. Structured telephone strategy had similar results to tele-monitoring including decreased risk of congestive heart failure hospitalization, without effect on mortality. Extrapolating from congestive heart failure data, it seems strategies to improve the health of pulmonary hypertension patients and development of comprehensive care programs should include structured telephone strategy and/or tele-monitoring, case management strategies, and multidisciplinary interventions.
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BACKGROUND: The DelIVery for Pulmonary Arterial Hypertension clinical trial was a multi-center, prospective, single arm, Investigational Device Exemption study utilizing a fully implantable, programmable intravascular delivery system consisting of a pump and a catheter for intravenous treprostinil. The study met its primary endpoint and demonstrated that the intravascular delivery system significantly reduced catheter related complications at 22,000 subject-days of follow-up compared with a predefined objective performance criterion. Here we summarize the results obtained during a 6.4-year follow-up period. METHODS: Throughout study follow-up, participants had clinic visits and medication refills at least every 12 weeks (dependent on the subjects' dose). All adverse events and intravascular delivery system complications were evaluated and recorded. RESULTS: Sixty pulmonary arterial hypertension subjects were followed post device implantation for approximately 282 patient-years (range 87 days to 6.4 years). Of the 60 subjects, 14 died (1 related to intravascular delivery system pump failure), 2 withdrew after lung transplants, and 2 withdrew due to pump pocket infection. No catheter-related bloodstream infections, catheter thrombosis or occlusions, or catheter kinks occurred through 282 patient-years. Two participants had adverse events of abdominal pain, rash, due to subcutaneous treprostinil "leaks" after one catheter puncture and one catheter laceration during pump refill and replacement, respectively. Eight pump failure events occurred: seven pump motor stalls and one early replacement (faulty battery). CONCLUSION: Delivery of treprostinil with an intravascular delivery system is a safe alternative to an external delivery system, while providing enhanced life experiences. To preserve the risk-benefit ratio, treatment at specialized pulmonary arterial hypertension centers is recommended until training is disseminated at other sites.
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The disability, mortality and costs caused by non-vertebral osteoporotic fractures are enormous. Existing osteoporosis therapies are highly effective at reducing vertebral but not non-vertebral fractures. Cortical bone is a major determinant of non-vertebral bone strength. To identify novel osteoporosis drug targets, we phenotyped cortical bone of 3 366 viable mouse strains with global knockouts of druggable genes. Cortical bone thickness was substantially elevated in Notum -/- mice. NOTUM is a secreted WNT lipase and we observed high NOTUM expression in cortical bone and osteoblasts but not osteoclasts. Three orally active small molecules and a neutralizing antibody inhibiting NOTUM lipase activity were developed. They increased cortical bone thickness and strength at multiple skeletal sites in both gonadal intact and ovariectomized rodents by stimulating endocortical bone formation. Thus, inhibition of NOTUM activity is a potential novel anabolic therapy for strengthening cortical bone and preventing non-vertebral fractures.
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The emergence of multicellular animals was associated with an increase in phenotypic complexity and with the acquisition of spatial cell differentiation and embryonic development. Paradoxically, this phenotypic transition was not paralleled by major changes in the underlying developmental toolkit and regulatory networks. In fact, most of these systems are ancient, established already in the unicellular ancestors of animals [1-5]. In contrast, the Microprocessor protein machinery, which is essential for microRNA (miRNA) biogenesis in animals, as well as the miRNA genes themselves produced by this Microprocessor, have not been identified outside of the animal kingdom [6]. Hence, the Microprocessor, with the key proteins Pasha and Drosha, is regarded as an animal innovation [7-9]. Here, we challenge this evolutionary scenario by investigating unicellular sister lineages of animals through genomic and transcriptomic analyses. We identify in Ichthyosporea both Drosha and Pasha (DGCR8 in vertebrates), indicating that the Microprocessor complex evolved long before the last common ancestor of animals, consistent with a pre-metazoan origin of most of the animal developmental gene elements. Through small RNA sequencing, we also discovered expressed bona fide miRNA genes in several species of the ichthyosporeans harboring the Microprocessor. A deep, pre-metazoan origin of the Microprocessor and miRNAs comply with a view that the origin of multicellular animals was not directly linked to the innovation of these key regulatory components.
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Evolución Molecular , Mesomycetozoea/genética , MicroARNs/genética , Animales , Secuencia de Bases , Mesomycetozoea/metabolismo , MicroARNs/metabolismo , FilogeniaRESUMEN
microRNAs are conserved noncoding regulatory factors implicated in diverse physiological and developmental processes in multicellular organisms, as causal macroevolutionary agents and for phylogeny inference. However, the conservation and phylogenetic utility of microRNAs has been questioned on evidence of pervasive loss. Here, we show that apparent widespread losses are, largely, an artefact of poorly sampled and annotated microRNAomes. Using a curated data set of animal microRNAomes, we reject the view that miRNA families are never lost, but they are rarely lost (92% are never lost). A small number of families account for a majority of losses (1.7% of families account for >45% losses), and losses are associated with lineages exhibiting phenotypic simplification. Phylogenetic analyses based on the presence/absence of microRNA families among animal lineages, and based on microRNA sequences among Osteichthyes, demonstrate the power of these small data sets in phylogenetic inference. Perceptions of widespread evolutionary loss of microRNA families are due to the uncritical use of public archives corrupted by spurious microRNA annotations, and failure to discriminate false absences that occur because of incomplete microRNAome annotation.
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MicroARNs/genética , Animales , Secuencia Conservada/genética , Evolución Molecular , Anotación de Secuencia Molecular/métodos , Fenotipo , FilogeniaRESUMEN
BACKGROUND: Prostacyclins improve symptoms and survival in pulmonary arterial hypertension (PAH). In response to risks associated with external delivery systems, an implantable IV infusion system was developed. A multicenter, prospective, single-arm, clinical trial (DelIVery for PAH) was conducted to evaluate this system for treprostinil in PAH. This analysis describes the findings related to the implant procedure. METHODS: Patients (N = 64) with PAH (World Health Organization group 1) receiving stable IV treprostinil were enrolled. Patients were transitioned to a temporary peripheral IV infusion catheter prior to the procedure. System implantation was performed at 10 centers under general anesthesia or deep IV sedation by clinicians from various specialties. Central venous access was via the cephalic, subclavian, jugular, or axillary vein. Using an introducer and fluoroscopic guidance, the distal tip of the infusion catheter was placed at the superior caval-atrial junction. The catheter was tunneled from the venous access site to an abdominal subcutaneous pocket, where the pump was placed. RESULTS: Of the 64 patients enrolled, four exited prior to implantation. All 60 implant procedures were successful. At baseline, all patients were receiving treprostinil via an external pump at a mean dose of 71.4 ± 27.8 ng/kg/min (range: 22-142 ng/kg/min). The implant averaged 102 ± 32 min (range: 47-184 min). Clinically significant implant procedure-related complications included one pneumothorax, two infections, and one episode of atrial fibrillation. There were three postimplantation catheter dislocations in two patients. Common implant-related events that were not complications included implant site pain (83%) and bruising (17%). CONCLUSIONS: The procedure for inserting a fully implantable system for treprostinil was successfully performed, with few complications. TRIAL REGISTRY: ClinicalTrials.gov; No.: NCT01321073; URL: www.clinicaltrials.gov.
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Cateterismo Venoso Central/métodos , Epoprostenol/análogos & derivados , Hipertensión Pulmonar/tratamiento farmacológico , Bombas de Infusión Implantables , Antihipertensivos/administración & dosificación , Relación Dosis-Respuesta a Droga , Epoprostenol/administración & dosificación , Femenino , Estudios de Seguimiento , Humanos , Hipertensión Pulmonar/diagnóstico , Hipertensión Pulmonar/fisiopatología , Infusiones Intravenosas , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Presión Esfenoidal Pulmonar/efectos de los fármacos , Resultado del TratamientoRESUMEN
Stringent searches for microRNAs (miRNAs) have so far only identified these molecules in animals, land plants, chlorophyte green algae, slime molds and brown algae. The identification of miRNAs in brown algae was based on the analysis of a single species, the filamentous brown alga Ectocarpus sp. Here, we have used deep sequencing of small RNAs and a recently published genome sequence to identify miRNAs in a second brown alga, the kelp Saccharina japonica. S. japonica possesses a large number of miRNAs (117) and these miRNAs are highly diverse, falling into 98 different families. Surprisingly, none of the S. japonica miRNAs share significant sequence similarity with the Ectocarpus sp. miRNAs. However, the miRNA repertoires of the two species share a number of structural and genomic features indicating that they were generated by similar evolutionary processes and therefore probably evolved within the context of a common, ancestral miRNA system. This lack of sequence similarity suggests that miRNAs evolve rapidly in the brown algae (the two species are separated by â¼95 Myr of evolution). The sets of predicted targets of miRNAs in the two species were also very different suggesting that the divergence of the miRNAs may have had significant consequences for miRNA function.
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Evolución Molecular , Genómica , MicroARNs/genética , Phaeophyceae/genética , Chlorophyta/genética , Genoma/genética , Secuenciación de Nucleótidos de Alto RendimientoRESUMEN
MicroRNAs are non-coding regulators of gene expression and key factors in development, disease, and targets for bioengineering. Consequently, microRNAs have become essential elements of already burgeoning draft plant genome descriptions where their annotation is often particularly poor, contributing unduly to the corruption of public databases. Using the Citrus sinensis as an example, we highlight and review common failings of miRNAome annotations. Understanding and exploiting the role of miRNAs in plant biology will be stymied unless the research community acts decisively to improve the accuracy of miRNAome annotations. We encourage genome annotation teams to do it right or not at all.
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Genoma de Planta , MicroARNs , Anotación de Secuencia Molecular , Plantas/genética , Citrus sinensis/genética , Guías como AsuntoRESUMEN
Morphological data provide the only means of classifying the majority of life's history, but the choice between competing phylogenetic methods for the analysis of morphology is unclear. Traditionally, parsimony methods have been favoured but recent studies have shown that these approaches are less accurate than the Bayesian implementation of the Mk model. Here we expand on these findings in several ways: we assess the impact of tree shape and maximum-likelihood estimation using the Mk model, as well as analysing data composed of both binary and multistate characters. We find that all methods struggle to correctly resolve deep clades within asymmetric trees, and when analysing small character matrices. The Bayesian Mk model is the most accurate method for estimating topology, but with lower resolution than other methods. Equal weights parsimony is more accurate than implied weights parsimony, and maximum-likelihood estimation using the Mk model is the least accurate method. We conclude that the Bayesian implementation of the Mk model should be the default method for phylogenetic estimation from phenotype datasets, and we explore the implications of our simulations in reanalysing several empirical morphological character matrices. A consequence of our finding is that high levels of resolution or the ability to classify species or groups with much confidence should not be expected when using small datasets. It is now necessary to depart from the traditional parsimony paradigms of constructing character matrices, towards datasets constructed explicitly for Bayesian methods.
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Fenotipo , Filogenia , Incertidumbre , Teorema de Bayes , Funciones de VerosimilitudRESUMEN
BACKGROUND: The use of systemic prostanoids in severe pulmonary arterial hypertension (PAH) is often limited by patient/physician dissatisfaction with the delivery methods. Complications associated with external pump-delivered continuous therapy include IV catheter-related bloodstream infections and subcutaneous infusion site pain. We therefore investigated a fully implantable intravascular delivery system for treprostinil infusion. METHODS: A multicenter, prospective, single-arm, clinical trial (DelIVery for Pulmonary Arterial Hypertension) was conducted by using an implantable intravascular delivery system. The implanted pumps were refilled percutaneously at least every 12 weeks. The primary end point was the rate of catheter-related complications using the new model 10642 catheter compared with a predefined objective performance criterion of 2.5 per 1,000 patient-days based on the literature. RESULTS: Patients (n = 60) with severe PAH (World Health Organization group 1) receiving a stable dose of IV treprostinil for at least 4 weeks received an implant device and were followed up for 12.1 ± 4.4 months. Six catheter-related complications occurred, corresponding to a complication rate of 0.27 per 1,000 patient-days. The 97.5% upper one-sided confidence bound of 0.59 was less than the predefined criterion of 2.5 per 1,000 patient-days (P < .0001). Plasma treprostinil levels at 1 week postimplantation were highly correlated with baseline levels (r = 0.91; P < .0001). The delivery system management time as reported by the patients was 2.5 ± 1.7 hours per week preimplantation, and this time decreased to 0.6 ± 0.8 hour per week at 6 months' postimplantation (P < .0001). All patients rated overall satisfaction with the implantable system as good, very good, or excellent at 6 weeks and 6 months. There were no catheter-related bloodstream infections or catheter occlusions. CONCLUSIONS: The implantable intravascular delivery system delivered treprostinil to patients with PAH with a low rate of catheter-related complications and a high rate of patient satisfaction. TRIAL REGISTRY: ClinicalTrials.gov; No.: NCT01321073; URL: www.clinicaltrials.gov.
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Efectos Colaterales y Reacciones Adversas Relacionados con Medicamentos , Epoprostenol/análogos & derivados , Hipertensión Pulmonar/tratamiento farmacológico , Bombas de Infusión Implantables/efectos adversos , Adulto , Antihipertensivos/administración & dosificación , Obstrucción del Catéter/estadística & datos numéricos , Infecciones Relacionadas con Catéteres/diagnóstico , Infecciones Relacionadas con Catéteres/epidemiología , Infecciones Relacionadas con Catéteres/etiología , Monitoreo de Drogas/métodos , Monitoreo de Drogas/estadística & datos numéricos , Efectos Colaterales y Reacciones Adversas Relacionados con Medicamentos/diagnóstico , Efectos Colaterales y Reacciones Adversas Relacionados con Medicamentos/etiología , Epoprostenol/administración & dosificación , Femenino , Humanos , Hipertensión Pulmonar/diagnóstico , Bombas de Infusión Implantables/estadística & datos numéricos , Masculino , Persona de Mediana Edad , Evaluación de Procesos y Resultados en Atención de Salud , Estudios Prospectivos , Estados UnidosRESUMEN
Different analytical methods can yield competing interpretations of evolutionary history and, currently, there is no definitive method for phylogenetic reconstruction using morphological data. Parsimony has been the primary method for analysing morphological data, but there has been a resurgence of interest in the likelihood-based Mk-model. Here, we test the performance of the Bayesian implementation of the Mk-model relative to both equal and implied-weight implementations of parsimony. Using simulated morphological data, we demonstrate that the Mk-model outperforms equal-weights parsimony in terms of topological accuracy, and implied-weights performs the most poorly. However, the Mk-model produces phylogenies that have less resolution than parsimony methods. This difference in the accuracy and precision of parsimony and Bayesian approaches to topology estimation needs to be considered when selecting a method for phylogeny reconstruction.
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Teorema de Bayes , Filogenia , Evolución Biológica , Simulación por Computador , Fósiles , Funciones de Verosimilitud , Modelos BiológicosRESUMEN
A group of small molecule thienopyrimidine inhibitors of Notum Pectinacetylesterase are described. We explored both 2-((5,6-thieno[2,3-d]pyrimidin-4-yl)thio)acetic acids and 2-((6,7-thieno[3,2-d]pyrimidin-4-yl)thio)acetic acids. In both series, highly potent, orally active Notum Pectinacetylesterase inhibitors were identified.
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Inhibidores Enzimáticos/farmacología , Esterasas/antagonistas & inhibidores , Fémur/efectos de los fármacos , Osteogénesis/efectos de los fármacos , Pirimidinas/farmacología , Animales , Relación Dosis-Respuesta a Droga , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/química , Esterasas/metabolismo , Fémur/anatomía & histología , Fémur/crecimiento & desarrollo , Humanos , Ratones , Estructura Molecular , Pirimidinas/síntesis química , Pirimidinas/química , Relación Estructura-ActividadRESUMEN
A group of small molecule thienochromenes inhibitors of Notum Pectinacetylesterase are described. We developed SAR on three series based on carbon, oxygen and sulfur replacement of the 5-position. In each series, highly potent Notum Pectinacetylesterase inhibitors were identified.
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Benzopiranos/química , Inhibidores Enzimáticos/química , Esterasas/antagonistas & inhibidores , Animales , Benzopiranos/farmacocinética , Benzopiranos/uso terapéutico , Inhibidores Enzimáticos/farmacocinética , Inhibidores Enzimáticos/uso terapéutico , Esterasas/metabolismo , Fémur/fisiología , Semivida , Humanos , Concentración 50 Inhibidora , Masculino , Ratones , Osteoporosis/tratamiento farmacológico , Osteoporosis/fisiopatología , Unión Proteica , Relación Estructura-ActividadRESUMEN
Placental mammals comprise three principal clades: Afrotheria (e.g., elephants and tenrecs), Xenarthra (e.g., armadillos and sloths), and Boreoeutheria (all other placental mammals), the relationships among which are the subject of controversy and a touchstone for debate on the limits of phylogenetic inference. Previous analyses have found support for all three hypotheses, leading some to conclude that this phylogenetic problem might be impossible to resolve due to the compounded effects of incomplete lineage sorting (ILS) and a rapid radiation. Here we show, using a genome scale nucleotide data set, microRNAs, and the reanalysis of the three largest previously published amino acid data sets, that the root of Placentalia lies between Atlantogenata and Boreoeutheria. Although we found evidence for ILS in early placental evolution, we are able to reject previous conclusions that the placental root is a hard polytomy that cannot be resolved. Reanalyses of previous data sets recover Atlantogenata + Boreoeutheria and show that contradictory results are a consequence of poorly fitting evolutionary models; instead, when the evolutionary process is better-modeled, all data sets converge on Atlantogenata. Our Bayesian molecular clock analysis estimates that marsupials diverged from placentals 157-170 Ma, crown Placentalia diverged 86-100 Ma, and crown Atlantogenata diverged 84-97 Ma. Our results are compatible with placental diversification being driven by dispersal rather than vicariance mechanisms, postdating early phases in the protracted opening of the Atlantic Ocean.
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Evolución Molecular , Mamíferos/genética , Modelos Genéticos , Filogenia , Placenta/anatomía & histología , Animales , Femenino , Fósiles , Especiación Genética , Genoma , Mamíferos/clasificación , MicroARNs/genética , EmbarazoRESUMEN
Although microRNAs (miRNAs) are among the most intensively studied molecules of the past 20 years, determining what is and what is not a miRNA has not been straightforward. Here, we present a uniform system for the annotation and nomenclature of miRNA genes. We show that less than a third of the 1,881 human miRBase entries, and only approximately 16% of the 7,095 metazoan miRBase entries, are robustly supported as miRNA genes. Furthermore, we show that the human repertoire of miRNAs has been shaped by periods of intense miRNA innovation and that mature gene products show a very different tempo and mode of sequence evolution than star products. We establish a new open access database--MirGeneDB ( http://mirgenedb.org )--to catalog this set of miRNAs, which complements the efforts of miRBase but differs from it by annotating the mature versus star products and by imposing an evolutionary hierarchy upon this curated and consistently named repertoire.
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Evolución Biológica , MicroARNs/genética , Anotación de Secuencia Molecular/métodos , Vertebrados/genética , Animales , Bases de Datos Genéticas , Evolución Molecular , Humanos , Terminología como AsuntoRESUMEN
Phenotypic plasticity is important in adaptation and shapes the evolution of organisms. However, we understand little about what aspects of the genome are important in facilitating plasticity. Eusocial insect societies produce plastic phenotypes from the same genome, as reproductives (queens) and nonreproductives (workers). The greatest plasticity is found in the simple eusocial insect societies in which individuals retain the ability to switch between reproductive and nonreproductive phenotypes as adults. We lack comprehensive data on the molecular basis of plastic phenotypes. Here, we sequenced genomes, microRNAs (miRNAs), and multiple transcriptomes and methylomes from individual brains in a wasp (Polistes canadensis) and an ant (Dinoponera quadriceps) that live in simple eusocial societies. In both species, we found few differences between phenotypes at the transcriptional level, with little functional specialization, and no evidence that phenotype-specific gene expression is driven by DNA methylation or miRNAs. Instead, phenotypic differentiation was defined more subtly by nonrandom transcriptional network organization, with roles in these networks for both conserved and taxon-restricted genes. The general lack of highly methylated regions or methylome patterning in both species may be an important mechanism for achieving plasticity among phenotypes during adulthood. These findings define previously unidentified hypotheses on the genomic processes that facilitate plasticity and suggest that the molecular hallmarks of social behavior are likely to differ with the level of social complexity.
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Hormigas/genética , Regulación de la Expresión Génica/genética , Jerarquia Social , Modelos Genéticos , Fenotipo , Conducta Social , Avispas/genética , Animales , Hormigas/fisiología , Secuencia de Bases , Encéfalo/metabolismo , Metilación de ADN/genética , Genoma de los Insectos/genética , Secuenciación de Nucleótidos de Alto Rendimiento , MicroARNs/genética , Datos de Secuencia Molecular , Transcriptoma/genética , Avispas/fisiologíaRESUMEN
There is currently convincing evidence that microRNAs have evolved independently in at least six different eukaryotic lineages: animals, land plants, chlorophyte green algae, demosponges, slime molds and brown algae. MicroRNAs from different lineages are not homologous but some structural features are strongly conserved across the eukaryotic tree allowing the application of stringent criteria to identify novel microRNA loci. A large set of 63 microRNA families was identified in the brown alga Ectocarpus based on mapping of RNA-seq data and nine microRNAs were confirmed by northern blotting. The Ectocarpus microRNAs are highly diverse at the sequence level with few multi-gene families, and do not tend to occur in clusters but exhibit some highly conserved structural features such as the presence of a uracil at the first residue. No homologues of Ectocarpus microRNAs were found in other stramenopile genomes indicating that they emerged late in stramenopile evolution and are perhaps specific to the brown algae. The large number of microRNA loci in Ectocarpus is consistent with the developmental complexity of many brown algal species and supports a proposed link between the emergence and expansion of microRNA regulatory systems and the evolution of complex multicellularity.
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Evolución Molecular , MicroARNs/genética , Phaeophyceae/genética , Sitios Genéticos , Variación Genética , Genoma , MicroARNs/química , MicroARNs/clasificación , MicroARNs/metabolismo , Phaeophyceae/metabolismo , Reacción en Cadena de la Polimerasa , Análisis de Secuencia de ARNRESUMEN
microRNAs (miRNAs) are short noncoding regulatory genes that perform important roles in plant development and physiology. With the increasing power of next generation sequencing technologies and the development of bioinformatic tools, there has been a dramatic increase in the number of studies surveying the miRNAomes of plant species, which has led to an explosion in the number of described miRNAs. Unfortunately, very many of these new discoveries have been incompletely annotated and thus fail to discriminate genuine miRNAs from small interfering RNAs (siRNAs), fragments of longer RNAs, and random sequence. We review the published repertoire of plant miRNAs, discriminating those that have been correctly annotated. We use these data to explore prevailing hypotheses on the tempo and mode of miRNA evolution within the plant kingdom.