RESUMO
Dexamethasone is a life-saving treatment for severe COVID-19, yet its mechanism of action is unknown, and many patients deteriorate or die despite timely treatment initiation. Here, we identify dexamethasone treatment-induced cellular and molecular changes associated with improved survival in COVID-19 patients. We observed a reversal of transcriptional hallmark signatures in monocytes associated with severe COVID-19 and the induction of a monocyte substate characterized by the expression of glucocorticoid-response genes. These molecular responses to dexamethasone were detected in circulating and pulmonary monocytes, and they were directly linked to survival. Monocyte single-cell RNA sequencing (scRNA-seq)-derived signatures were enriched in whole blood transcriptomes of patients with fatal outcome in two independent cohorts, highlighting the potential for identifying non-responders refractory to dexamethasone. Our findings link the effects of dexamethasone to specific immunomodulation and reversal of monocyte dysregulation, and they highlight the potential of single-cell omics for monitoring in vivo target engagement of immunomodulatory drugs and for patient stratification for precision medicine approaches.
Assuntos
Tratamento Farmacológico da COVID-19 , COVID-19 , Dexametasona , Monócitos , SARS-CoV-2 , Análise de Célula Única , Humanos , Dexametasona/farmacologia , Dexametasona/uso terapêutico , Monócitos/metabolismo , Monócitos/efeitos dos fármacos , SARS-CoV-2/efeitos dos fármacos , Masculino , Feminino , Transcriptoma , Pessoa de Meia-Idade , Idoso , Glucocorticoides/uso terapêutico , Glucocorticoides/farmacologia , Pulmão/patologia , AdultoRESUMO
Spatially resolved omics technologies reveal context-dependent cellular regulatory networks in tissues of interest. Beyond transcriptome analysis, information on epigenetic traits and chromatin accessibility can provide further insights on gene regulation in health and disease. Nevertheless, compared to the enormous advancements in spatial transcriptomics technologies, the field of spatial epigenomics is much younger and still underexplored. In this study, we report laser capture microdissection coupled to ATAC-seq (LCM-ATAC-seq) applied to fresh frozen samples for the spatial characterization of chromatin accessibility. We first demonstrate the efficient use of LCM coupled to in situ tagmentation and evaluate its performance as a function of cell number, microdissected areas, and tissue type. Further, we demonstrate its use for the targeted chromatin accessibility analysis of discrete contiguous or scattered cell populations in tissues via single-nuclei capture based on immunostaining for specific cellular markers.
Assuntos
Sequenciamento de Cromatina por Imunoprecipitação , Cromatina , Cromatina/genética , Microdissecção e Captura a Laser , Perfilação da Expressão Gênica , CongelamentoRESUMO
Systemic inflammation is established as part of late-stage severe lung disease, but molecular, functional, and phenotypic changes in peripheral immune cells in early disease stages remain ill defined. Chronic obstructive pulmonary disease (COPD) is a major respiratory disease characterized by small-airway inflammation, emphysema, and severe breathing difficulties. Using single-cell analyses we demonstrate that blood neutrophils are already increased in early-stage COPD, and changes in molecular and functional neutrophil states correlate with lung function decline. Assessing neutrophils and their bone marrow precursors in a murine cigarette smoke exposure model identified similar molecular changes in blood neutrophils and precursor populations that also occur in the blood and lung. Our study shows that systemic molecular alterations in neutrophils and their precursors are part of early-stage COPD, a finding to be further explored for potential therapeutic targets and biomarkers for early diagnosis and patient stratification.
Assuntos
Doença Pulmonar Obstrutiva Crônica , Enfisema Pulmonar , Humanos , Animais , Camundongos , Neutrófilos , Doença Pulmonar Obstrutiva Crônica/tratamento farmacológico , Pulmão , InflamaçãoRESUMO
Despite its high prevalence, the cellular and molecular mechanisms of chronic obstructive pulmonary disease (COPD) are far from being understood. Here, we determine disease-related changes in cellular and molecular compositions within the alveolar space and peripheral blood of a cohort of COPD patients and controls. Myeloid cells were the largest cellular compartment in the alveolar space with invading monocytes and proliferating macrophages elevated in COPD. Modeling cell-to-cell communication, signaling pathway usage, and transcription factor binding predicts TGF-ß1 to be a major upstream regulator of transcriptional changes in alveolar macrophages of COPD patients. Functionally, macrophages in COPD showed reduced antigen presentation capacity, accumulation of cholesteryl ester, reduced cellular chemotaxis, and mitochondrial dysfunction, reminiscent of impaired immune activation.
Assuntos
Macrófagos Alveolares , Doença Pulmonar Obstrutiva Crônica , Quimiotaxia/fisiologia , Humanos , Macrófagos/metabolismo , Monócitos/metabolismoRESUMO
The primary cilium constitutes an organelle that orchestrates signal transduction independently from the cell body. Dysregulation of this intricate molecular architecture leads to severe human diseases, commonly referred to as ciliopathies. However, the molecular underpinnings how ciliary signaling orchestrates a specific cellular output remain elusive. By combining spatially resolved optogenetics with RNA sequencing and imaging, we reveal a novel cAMP signalosome that is functionally distinct from the cytoplasm. We identify the genes and pathways targeted by the ciliary cAMP signalosome and shed light on the underlying mechanisms and downstream signaling. We reveal that chronic stimulation of the ciliary cAMP signalosome transforms kidney epithelia from tubules into cysts. Counteracting this chronic cAMP elevation in the cilium by small molecules targeting activation of phosphodiesterase-4 long isoforms inhibits cyst growth. Thereby, we identify a novel concept of how the primary cilium controls cellular functions and maintains tissue integrity in a specific and spatially distinct manner and reveal novel molecular components that might be involved in the development of one of the most common genetic diseases, polycystic kidney disease.
Assuntos
Cistos , Doenças Renais Policísticas , Cílios/metabolismo , Cistos/metabolismo , Expressão Gênica , Humanos , Rim , Doenças Renais Policísticas/genética , Doenças Renais Policísticas/metabolismoRESUMO
Hydrocephalus, characterized by cerebral ventricular dilatation, is routinely attributed to primary defects in cerebrospinal fluid (CSF) homeostasis. This fosters CSF shunting as the leading reason for brain surgery in children despite considerable disease heterogeneity. In this study, by integrating human brain transcriptomics with whole-exome sequencing of 483 patients with congenital hydrocephalus (CH), we found convergence of CH risk genes in embryonic neuroepithelial stem cells. Of all CH risk genes, TRIM71/lin-41 harbors the most de novo mutations and is most specifically expressed in neuroepithelial cells. Mice harboring neuroepithelial cell-specific Trim71 deletion or CH-specific Trim71 mutation exhibit prenatal hydrocephalus. CH mutations disrupt TRIM71 binding to its RNA targets, causing premature neuroepithelial cell differentiation and reduced neurogenesis. Cortical hypoplasia leads to a hypercompliant cortex and secondary ventricular enlargement without primary defects in CSF circulation. These data highlight the importance of precisely regulated neuroepithelial cell fate for normal brain-CSF biomechanics and support a clinically relevant neuroprogenitor-based paradigm of CH.
Assuntos
Hidrocefalia , Animais , Fenômenos Biomecânicos , Encéfalo/metabolismo , Líquido Cefalorraquidiano/metabolismo , Humanos , Hidrocefalia/líquido cefalorraquidiano , Hidrocefalia/genética , Camundongos , Neurogênese/genética , Proteínas com Motivo Tripartido/genética , Proteínas com Motivo Tripartido/metabolismo , Ubiquitina-Proteína Ligases/genética , Sequenciamento do ExomaRESUMO
The Human Cell Atlas (HCA) consortium aims to establish an atlas of all organs in the healthy human body at single-cell resolution to increase our understanding of basic biological processes that govern development, physiology and anatomy, and to accelerate diagnosis and treatment of disease. The Lung Biological Network of the HCA aims to generate the Human Lung Cell Atlas as a reference for the cellular repertoire, molecular cell states and phenotypes, and cell-cell interactions that characterise normal lung homeostasis in healthy lung tissue. Such a reference atlas of the healthy human lung will facilitate mapping the changes in the cellular landscape in disease. The discovAIR project is one of six pilot actions for the HCA funded by the European Commission in the context of the H2020 framework programme. discovAIR aims to establish the first draft of an integrated Human Lung Cell Atlas, combining single-cell transcriptional and epigenetic profiling with spatially resolving techniques on matched tissue samples, as well as including a number of chronic and infectious diseases of the lung. The integrated Human Lung Cell Atlas will be available as a resource for the wider respiratory community, including basic and translational scientists, clinical medicine, and the private sector, as well as for patients with lung disease and the interested lay public. We anticipate that the Human Lung Cell Atlas will be the founding stone for a more detailed understanding of the pathogenesis of lung diseases, guiding the design of novel diagnostics and preventive or curative interventions.
Assuntos
Pneumopatias , Pulmão , Humanos , Proteômica , TóraxRESUMO
Xenopus laevis are able to regenerate the spinal cord during larvae stages through the activation of neural stem progenitor cells (NSPCs). Here we use high-resolution expression profiling to characterize the early transcriptome changes induced after spinal cord injury, aiming to identify the signals that trigger NSPC proliferation. The analysis delineates a pathway that starts with a rapid and transitory activation of immediate early genes, followed by migration processes and immune response genes, the pervasive increase of NSPC-specific ribosome biogenesis factors, and genes involved in stem cell proliferation. Western blot and immunofluorescence analysis showed that mTORC1 is rapidly and transiently activated after SCI, and its pharmacological inhibition impairs spinal cord regeneration and proliferation of NSPC through the downregulation of genes involved in the G1/S transition of cell cycle, with a strong effect on PCNA. We propose that the mTOR signaling pathway is a key player in the activation of NPSCs during the early steps of spinal cord regeneration.
RESUMO
Longitudinal analyses of the innate immune system, including the earliest time points, are essential to understand the immunopathogenesis and clinical course of coronavirus disease (COVID-19). Here, we performed a detailed characterization of natural killer (NK) cells in 205 patients (403 samples; days 2 to 41 after symptom onset) from four independent cohorts using single-cell transcriptomics and proteomics together with functional studies. We found elevated interferon (IFN)-α plasma levels in early severe COVD-19 alongside increased NK cell expression of IFN-stimulated genes (ISGs) and genes involved in IFN-α signaling, while upregulation of tumor necrosis factor (TNF)-induced genes was observed in moderate diseases. NK cells exert anti-SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) activity but are functionally impaired in severe COVID-19. Further, NK cell dysfunction may be relevant for the development of fibrotic lung disease in severe COVID-19, as NK cells exhibited impaired anti-fibrotic activity. Our study indicates preferential IFN-α and TNF responses in severe and moderate COVID-19, respectively, and associates a prolonged IFN-α-induced NK cell response with poorer disease outcome.
Assuntos
COVID-19/imunologia , Interferon-alfa/imunologia , Células Matadoras Naturais/imunologia , SARS-CoV-2/imunologia , Fator de Necrose Tumoral alfa/metabolismo , Sequência de Bases , Humanos , Imunidade Inata/imunologia , Inflamação/imunologia , Interferon-alfa/sangue , Fibrose Pulmonar/patologia , RNA-Seq , Índice de Gravidade de Doença , Transcriptoma/genética , Reino Unido , Estados UnidosRESUMO
Fast and reliable detection of patients with severe and heterogeneous illnesses is a major goal of precision medicine1,2. Patients with leukaemia can be identified using machine learning on the basis of their blood transcriptomes3. However, there is an increasing divide between what is technically possible and what is allowed, because of privacy legislation4,5. Here, to facilitate the integration of any medical data from any data owner worldwide without violating privacy laws, we introduce Swarm Learning-a decentralized machine-learning approach that unites edge computing, blockchain-based peer-to-peer networking and coordination while maintaining confidentiality without the need for a central coordinator, thereby going beyond federated learning. To illustrate the feasibility of using Swarm Learning to develop disease classifiers using distributed data, we chose four use cases of heterogeneous diseases (COVID-19, tuberculosis, leukaemia and lung pathologies). With more than 16,400 blood transcriptomes derived from 127 clinical studies with non-uniform distributions of cases and controls and substantial study biases, as well as more than 95,000 chest X-ray images, we show that Swarm Learning classifiers outperform those developed at individual sites. In addition, Swarm Learning completely fulfils local confidentiality regulations by design. We believe that this approach will notably accelerate the introduction of precision medicine.
Assuntos
Blockchain , Tomada de Decisão Clínica/métodos , Confidencialidade , Conjuntos de Dados como Assunto , Aprendizado de Máquina , Medicina de Precisão/métodos , COVID-19/diagnóstico , COVID-19/epidemiologia , Surtos de Doenças , Feminino , Humanos , Leucemia/diagnóstico , Leucemia/patologia , Leucócitos/patologia , Pneumopatias/diagnóstico , Aprendizado de Máquina/tendências , Masculino , Software , Tuberculose/diagnósticoRESUMO
Strong evidence has been accumulated since the beginning of the COVID-19 pandemic that neutrophils play an important role in the pathophysiology, particularly in those with severe disease courses. While originally considered to be a rather homogeneous cell type, recent attention to neutrophils has uncovered their fascinating transcriptional and functional diversity as well as their developmental trajectories. These new findings are important to better understand the many facets of neutrophil involvement not only in COVID-19 but also many other acute or chronic inflammatory diseases, both communicable and non-communicable. Here, we highlight the observed immune deviation of neutrophils in COVID-19 and summarize several promising therapeutic attempts to precisely target neutrophils and their reactivity in patients with COVID-19.
Assuntos
COVID-19/epidemiologia , COVID-19/imunologia , Neutrófilos/imunologia , Pandemias , SARS-CoV-2/imunologia , HumanosRESUMO
BACKGROUND: The SARS-CoV-2 pandemic is currently leading to increasing numbers of COVID-19 patients all over the world. Clinical presentations range from asymptomatic, mild respiratory tract infection, to severe cases with acute respiratory distress syndrome, respiratory failure, and death. Reports on a dysregulated immune system in the severe cases call for a better characterization and understanding of the changes in the immune system. METHODS: In order to dissect COVID-19-driven immune host responses, we performed RNA-seq of whole blood cell transcriptomes and granulocyte preparations from mild and severe COVID-19 patients and analyzed the data using a combination of conventional and data-driven co-expression analysis. Additionally, publicly available data was used to show the distinction from COVID-19 to other diseases. Reverse drug target prediction was used to identify known or novel drug candidates based on finding from data-driven findings. RESULTS: Here, we profiled whole blood transcriptomes of 39 COVID-19 patients and 10 control donors enabling a data-driven stratification based on molecular phenotype. Neutrophil activation-associated signatures were prominently enriched in severe patient groups, which was corroborated in whole blood transcriptomes from an independent second cohort of 30 as well as in granulocyte samples from a third cohort of 16 COVID-19 patients (44 samples). Comparison of COVID-19 blood transcriptomes with those of a collection of over 3100 samples derived from 12 different viral infections, inflammatory diseases, and independent control samples revealed highly specific transcriptome signatures for COVID-19. Further, stratified transcriptomes predicted patient subgroup-specific drug candidates targeting the dysregulated systemic immune response of the host. CONCLUSIONS: Our study provides novel insights in the distinct molecular subgroups or phenotypes that are not simply explained by clinical parameters. We show that whole blood transcriptomes are extremely informative for COVID-19 since they capture granulocytes which are major drivers of disease severity.
Assuntos
COVID-19/patologia , Neutrófilos/metabolismo , Transcriptoma , Antivirais/uso terapêutico , COVID-19/virologia , Estudos de Casos e Controles , Regulação para Baixo , Reposicionamento de Medicamentos , Humanos , Neutrófilos/citologia , Neutrófilos/imunologia , Fenótipo , Análise de Componente Principal , RNA/sangue , RNA/química , RNA/metabolismo , Análise de Sequência de RNA , Índice de Gravidade de Doença , Regulação para Cima , Tratamento Farmacológico da COVID-19RESUMO
In December 2019, a new coronavirus, SARS-CoV-2, which causes the respiratory illness that led to the COVID-19 pandemic, was reported. In the face of such a new pathogen, special precautions must be taken to examine potentially infectious materials due to the lack of knowledge on disease transmissibility, infectivity, and molecular pathogenicity. Here, we present a complete and safe workflow for performing scRNA-seq experiments on blood samples of infected patients from cell isolation to data analysis using the micro-well based BD Rhapsody platform. For complete information on the use and execution of this protocol, please refer to Schulte-Schrepping et al. (2020).
Assuntos
COVID-19 , Doenças Transmissíveis , RNA-Seq/métodos , Análise de Célula Única/métodos , Transcriptoma/genética , Biomarcadores/sangue , COVID-19/genética , COVID-19/metabolismo , Doenças Transmissíveis/genética , Doenças Transmissíveis/metabolismo , Humanos , SARS-CoV-2 , Fluxo de TrabalhoRESUMO
Coronavirus disease 2019 (COVID-19) is a mild to moderate respiratory tract infection, however, a subset of patients progress to severe disease and respiratory failure. The mechanism of protective immunity in mild forms and the pathogenesis of severe COVID-19 associated with increased neutrophil counts and dysregulated immune responses remain unclear. In a dual-center, two-cohort study, we combined single-cell RNA-sequencing and single-cell proteomics of whole-blood and peripheral-blood mononuclear cells to determine changes in immune cell composition and activation in mild versus severe COVID-19 (242 samples from 109 individuals) over time. HLA-DRhiCD11chi inflammatory monocytes with an interferon-stimulated gene signature were elevated in mild COVID-19. Severe COVID-19 was marked by occurrence of neutrophil precursors, as evidence of emergency myelopoiesis, dysfunctional mature neutrophils, and HLA-DRlo monocytes. Our study provides detailed insights into the systemic immune response to SARS-CoV-2 infection and reveals profound alterations in the myeloid cell compartment associated with severe COVID-19.
Assuntos
Infecções por Coronavirus/imunologia , Células Mieloides/imunologia , Mielopoese , Pneumonia Viral/imunologia , Adulto , Idoso , Antígenos CD11/genética , Antígenos CD11/metabolismo , COVID-19 , Células Cultivadas , Infecções por Coronavirus/sangue , Infecções por Coronavirus/patologia , Feminino , Antígenos HLA-DR/genética , Antígenos HLA-DR/metabolismo , Humanos , Masculino , Pessoa de Meia-Idade , Células Mieloides/citologia , Pandemias , Pneumonia Viral/sangue , Pneumonia Viral/patologia , Proteoma/genética , Proteoma/metabolismo , Proteômica , Análise de Célula ÚnicaRESUMO
Here we consider RNA-Seq, used to measure global gene expression through RNA fragmentation, capture, sequencing, and subsequent computational analysis. Xenopus, with its large number of RNA-rich, synchronously developing, and accessible embryos, is an excellent model organism for exploiting the power of high-throughput sequencing to understand gene expression during development. Here we present a standard RNA-Seq protocol for performing two-state differential gene expression analysis (between groups of replicates of control and treated embryos) using Illumina sequencing. Samples contain multiple whole embryos, and polyadenylated mRNA is measured under relative normalization. The protocol is divided into two parts: wet-lab processes to prepare samples for sequencing and downstream computational analysis including quality control, quantification of gene expression, and differential expression.
Assuntos
Perfilação da Expressão Gênica/métodos , RNA-Seq/métodos , Animais , Regulação da Expressão Gênica no Desenvolvimento , Biblioteca Gênica , Manejo de Espécimes , Xenopus/embriologiaRESUMO
Correct development of the vertebrate body plan requires the early definition of two asymmetric, perpendicular axes. The first axis is established during oocyte maturation, and the second is established by symmetry breaking shortly after fertilization. The physical processes generating the second asymmetric, or dorsal-ventral, axis are well understood, but the specific molecular determinants, presumed to be maternal gene products, are poorly characterized. Whilst enrichment of maternal mRNAs at the animal and vegetal poles in both the oocyte and the early embryo has been studied, little is known about the distribution of maternal mRNAs along either the dorsal-ventral or left-right axes during the early cleavage stages. Here we report an unbiased analysis of the distribution of maternal mRNA on all axes of the Xenopus tropicalis 8-cell stage embryo, based on sequencing of single blastomeres whose positions within the embryo are known. Analysis of pooled data from complete sets of blastomeres from four embryos has identified 908 mRNAs enriched in either the animal or vegetal blastomeres, of which 793 are not previously reported as enriched. In contrast, we find no evidence for asymmetric distribution along either the dorsal-ventral or left-right axes. We confirm that animal pole enrichment is on average distinctly lower than vegetal pole enrichment, and that considerable variation is found between reported enrichment levels in different studies. We use publicly available data to show that there is a significant association between genes with human disease annotation and enrichment at the animal pole. Mutations in the human ortholog of the most animally enriched novel gene, Slc35d1, are causative for Schneckenbecken dysplasia, and we show that a similar phenotype is produced by depletion of the orthologous protein in Xenopus embryos.
Assuntos
Blastômeros/metabolismo , Xenopus/embriologia , Xenopus/genética , Animais , Padronização Corporal/genética , Feminino , Técnicas de Silenciamento de Genes , Humanos , Masculino , Modelos Animais , Proteínas de Transporte de Monossacarídeos/antagonistas & inibidores , Proteínas de Transporte de Monossacarídeos/genética , Mutação , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Transcrição Gênica , Xenopus/metabolismo , Proteínas de Xenopus/antagonistas & inibidores , Proteínas de Xenopus/genéticaRESUMO
The Xenopus mid-blastula transition (MBT) marks the onset of large-scale zygotic transcription, as well as an increase in cell cycle length and a loss of synchronous cell divisions. Little is known about what triggers the activation of transcription or how newly expressed genes interact with each other. Here, we use high-resolution expression profiling to identify three waves of gene activity: a post-fertilisation wave involving polyadenylation of maternal transcripts; a broad wave of zygotic transcription detectable as early as the seventh cleavage and extending beyond the MBT at the twelfth cleavage; and a shorter post-MBT wave of transcription that becomes apparent as development proceeds. Our studies have also allowed us to define a set of maternal mRNAs that are deadenylated shortly after fertilisation, and are likely to be degraded thereafter. Experimental analysis indicates that the polyadenylation of maternal transcripts is necessary for the establishment of proper levels of zygotic transcription at the MBT, and that genes activated in the second wave of expression, including Brachyury and Mixer, contribute to the regulation of genes expressed in the third. Together, our high-resolution time series and experimental studies have yielded a deeper understanding of the temporal organisation of gene regulatory networks in the early Xenopus embryo.
Assuntos
Blástula/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Xenopus/embriologia , Xenopus/genética , Animais , Embrião não Mamífero/metabolismo , Perfilação da Expressão Gênica , Anotação de Sequência Molecular , Poli A/metabolismo , Poliadenilação/genética , Estabilidade de RNA/genética , RNA Mensageiro Estocado/genética , RNA Mensageiro Estocado/metabolismo , Reprodutibilidade dos Testes , Fatores de Transcrição/metabolismo , Transcrição Gênica , Proteínas de Xenopus/genética , Proteínas de Xenopus/metabolismo , Peixe-Zebra/genéticaRESUMO
Continuous light treatment during early juvenile stages in Gadus morhua is a common farming management practice but the effects of these unnatural light conditions on fish stress have received scant attention. In the present study we investigated how continuous illumination affects transcription levels of key stress-related and antimicrobial peptide genes in juvenile Atlantic cod. Gene expression quantification by real-time PCR revealed higher levels of transcripts coding for antioxidant enzymes, namely superoxide dismutase, catalase and glutathione reductase in liver of fish reared under continuous illumination, concomitantly with a 43% decrease in glutathione content. Transcription of antimicrobial peptides such as piscidins, hepcidin and cathelicidin was also affected by constant illumination. Overall, the significant changes in liver transcript levels of these biomarkers in response to continuous light may be an adaptation to light stress.
Assuntos
Gadus morhua/imunologia , Luz , Estresse Fisiológico , Adaptação Ocular , Animais , Peptídeos Catiônicos Antimicrobianos/genética , Peptídeos Catiônicos Antimicrobianos/metabolismo , Biomarcadores/metabolismo , Catalase/genética , Catalase/metabolismo , Regulação da Expressão Gênica , Glutationa Redutase/genética , Glutationa Redutase/metabolismo , Luz/efeitos adversos , Estresse Oxidativo , Estresse Fisiológico/genética , Superóxido Dismutase/genética , Superóxido Dismutase/metabolismoRESUMO
Multiple anthropogenic activities present along coastal environments may affect the health status of aquatic ecosystems. In this study, specimens of European sea bass (Dicentrarchus labrax) were exposed for 30 days to highly contaminated sediment collected from the industrial area between Augusta and Priolo (Syracuse, Italy), defined as the most mercury polluted site in the Mediterranean. The aim was to evaluate the responses of juvenile D. labrax to highly contaminated sediments, particularly enriched in Hg, in order to enhance the scarce knowledge on the potential compensatory mechanisms developed by organisms under severe stress conditions. Apoptotic and proliferative activities [cell turnover: Proliferating Cell Nuclear Antigen (PCNA) and FAS Ligand (FasL)], onset of hypoxic condition [hypoxia: Hypoxia Inducibile Factor-1α (HIF-1α)], and changes in the neuroendocrine control mechanisms [neurotransmission: Tyrosine Hydroxylase (TH), Choline Acetyltransferase (ChAT), Acetylcholinesterase (AChE), 5-Hydroxytryptamine (5-HT) and 5-Hydroxytryptamine receptor 3 (5-HT3)] were investigated in sea bass gill tissues. In the specimens exposed to the polluted sediment, the occurrence of altered cell turnover may result in impaired gas exchange that leads to a condition of "functional hypoxia". Changes in neurotransmission pathways were also observed, suggesting a remodeling process as an adaptive response to increase the O2-carrying capacity and restore the normal physiological conditions of the gills. Overall, these findings demonstrated that although chronic exposure to heavy metal polluted sediments alters the functioning of both the nervous and endocrine systems, as well as plasticity of the gill epithelium, fish are able to trigger a series of physiological adjustments or adaptations interfering with specific neuroendocrine control mechanisms that enable their long-term survival.
Assuntos
Bass/fisiologia , Brânquias/efeitos dos fármacos , Metais Pesados/toxicidade , Poluentes do Solo/toxicidade , Anaerobiose/efeitos dos fármacos , Animais , Apoptose/efeitos dos fármacos , Western Blotting , Proliferação de Células/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos dos fármacos , Brânquias/citologia , Itália , Transmissão Sináptica/efeitos dos fármacosRESUMO
Environmental metabolomics was applied to assess the metabolic responses in transplanted mussels to environmental pollution. Specimens of Mytilus galloprovincialis, sedentary filter-feeders, were caged in anthropogenic-impacted and reference sites along the Augusta coastline (Sicily, Italy). Chemical analysis revealed increased levels of PAHs in the digestive gland of mussels from the industrial area compared with control, and marked morphological changes were also observed. Digestive gland metabolic profiles, obtained by 1H NMR spectroscopy and analyzed by multivariate statistics, showed changes in metabolites involved in energy metabolism. Specifically, changes in lactate and acetoacetate could indicate increased anaerobic fermentation and alteration in lipid metabolism, respectively, suggesting that the mussels transplanted to the contaminated field site were suffering from adverse environmental condition. The NMR-based environmental metabolomics applied in this study results thus in it being a useful and effective tool for assessing environmental influences on the health status of aquatic organisms.