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2.
Elife ; 102021 10 05.
Artigo em Inglês | MEDLINE | ID: mdl-34609281

RESUMO

Brain microglia and border-associated macrophages (BAMs) display distinct spatial, developmental, and phenotypic features. Although at steady state, the origins of distinct brain macrophages are well-documented, the dynamics of their replenishment in neurodegenerative disorders remain elusive, particularly for activated CD11c+ microglia and BAMs. In this study, we conducted a comprehensive fate-mapping analysis of murine microglia and BAMs and their turnover kinetics during Alzheimer's disease (AD) progression. We used a novel inducible AD mouse model to investigate the contribution of bone marrow (BM) cells to the pool of fetal-derived brain macrophages during the development of AD. We demonstrated that microglia remain a remarkably stable embryonic-derived population even during the progression of AD pathology, indicating that neither parenchymal macrophage subpopulation originates from, nor is replenished by, BM-derived cells. At the border-associated brain regions, bona fide CD206+ BAMs are minimally replaced by BM-derived cells, and their turnover rates are not accelerated by AD. In contrast, all other myeloid cells are swiftly replenished by BM progenitors. This information further elucidates the turnover kinetics of these cells not only at steady state, but also in neurodegenerative diseases, which is crucial for identifying potential novel therapeutic targets.


Assuntos
Doença de Alzheimer/metabolismo , Lectinas Tipo C/metabolismo , Macrófagos/metabolismo , Lectinas de Ligação a Manose/metabolismo , Microglia/metabolismo , Receptores de Superfície Celular/metabolismo , Doença de Alzheimer/embriologia , Animais , Modelos Animais de Doenças , Camundongos
3.
Nat Commun ; 12(1): 6010, 2021 10 14.
Artigo em Inglês | MEDLINE | ID: mdl-34650077

RESUMO

Lizards regenerate amputated tails but fail to recapitulate the dorsoventral patterning achieved during embryonic development. Regenerated lizard tails form ependymal tubes (ETs) that, like embryonic tail neural tubes (NTs), induce cartilage differentiation in surrounding cells via sonic hedgehog (Shh) signaling. However, adult ETs lack characteristically roof plate-associated structures and express Shh throughout their circumferences, resulting in the formation of unpatterned cartilage tubes. Both NTs and ETs contain neural stem cells (NSCs), but only embryonic NSC populations differentiate into roof plate identities when protected from endogenous Hedgehog signaling. NSCs were isolated from parthenogenetic lizard embryos, rendered unresponsive to Hedgehog signaling via CRISPR/Cas9 gene knockout of smoothened (Smo), and implanted back into clonally-identical adults to regulate tail regeneration. Here we report that Smo knockout embryonic NSCs oppose cartilage formation when engrafted to adult ETs, representing an important milestone in the creation of regenerated lizard tails with dorsoventrally patterned skeletal tissues.


Assuntos
Células-Tronco Embrionárias/fisiologia , Edição de Genes , Lagartos/genética , Lagartos/fisiologia , Células-Tronco Neurais/fisiologia , Regeneração/fisiologia , Cauda/fisiologia , Animais , Padronização Corporal/genética , Padronização Corporal/fisiologia , Sistemas CRISPR-Cas , Cartilagem , Epêndima , Lagartos/embriologia , Transdução de Sinais/genética , Receptor Smoothened/genética , Medula Espinal/fisiologia
4.
Hum Genet ; 140(12): 1733-1751, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34647195

RESUMO

Mitochondrial disorders are collectively common, genetically heterogeneous disorders in both pediatric and adult populations. They are caused by molecular defects in oxidative phosphorylation, failure of essential bioenergetic supply to mitochondria, and apoptosis. Here, we present three affected individuals from a consanguineous family of Pakistani origin with variable seizures and intellectual disability. Both females display primary ovarian insufficiency (POI), while the male shows abnormal sex hormone levels. We performed whole exome sequencing and identified a recessive missense variant c.694C > T, p.Arg232Cys in TFAM that segregates with disease. TFAM (mitochondrial transcription factor A) is a component of the mitochondrial replisome machinery that maintains mtDNA transcription and replication. In primary dermal fibroblasts, we show depletion of mtDNA and significantly altered mitochondrial function and morphology. Moreover, we observed reduced nucleoid numbers with significant changes in nucleoid size or shape in fibroblasts from an affected individual compared to controls. We also investigated the effect of tfam impairment in zebrafish; homozygous tfam mutants carrying an in-frame c.141_149 deletion recapitulate the mtDNA depletion and ovarian dysgenesis phenotypes observed in affected humans. Together, our genetic and functional data confirm that TFAM plays a pivotal role in gonad development and expands the repertoire of mitochondrial disease phenotypes.


Assuntos
DNA Mitocondrial , Proteínas de Ligação a DNA/genética , Genes Recessivos , Perda Auditiva/genética , Deficiência Intelectual/genética , Proteínas Mitocondriais/genética , Insuficiência Ovariana Primária/genética , Convulsões/genética , Fatores de Transcrição/genética , Animais , Células Cultivadas , Feminino , Gônadas/embriologia , Humanos , Masculino , Linhagem , Peixe-Zebra/genética
5.
Elife ; 102021 10 05.
Artigo em Inglês | MEDLINE | ID: mdl-34609280

RESUMO

During morphogenesis, epithelial sheets remodel into complex geometries. How cells dynamically organise their contact with neighbouring cells in these tightly packed tissues is poorly understood. We have used light-sheet microscopy of growing mouse embryonic lung explants, three-dimensional cell segmentation, and physical theory to unravel the principles behind 3D cell organisation in growing pseudostratified epithelia. We find that cells have highly irregular 3D shapes and exhibit numerous neighbour intercalations along the apical-basal axis as well as over time. Despite the fluidic nature, the cell packing configurations follow fundamental relationships previously described for apical epithelial layers, that is, Euler's polyhedron formula, Lewis' law, and Aboav-Weaire's law, at all times and across the entire tissue thickness. This arrangement minimises the lateral cell-cell surface energy for a given cross-sectional area variability, generated primarily by the distribution and movement of nuclei. We conclude that the complex 3D cell organisation in growing epithelia emerges from simple physical principles.


Assuntos
Pulmão/embriologia , Animais , Células Epiteliais/citologia , Epitélio/embriologia , Camundongos , Morfogênese
6.
Neuropharmacology ; 201: 108841, 2021 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-34666076

RESUMO

A strong association between perinatal viral infections and neurodevelopmental disorders has been established. Both the direct contact of the virus with the developing brain and the strong maternal immune response originated by viral infections can impair proper neurodevelopment. Coronavirus disease 2019 (COVID-19), caused by the highly-infectious severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is currently responsible for a large global outbreak and is a major public health issue. While initial studies focused on the viral impact on the respiratory system, increasing evidence suggest that SARS-CoV-2 infects other organs and tissues including the mature brain. While studies continue to determine the neuropathology associated to COVID-19, the consequences of SARS-CoV-2 infection to the developing brain remain largely unexplored. The present review discusses evidence suggesting that SARS-CoV-2 infection may have persistent effects on the course of pregnancy and on brain development. Studies have shown that several proinflammatory mediators which are increased in the SARS-CoV-2-associated cytokine storm, are also modified in other viral infections known to increase the risk of neurodevelopmental disorders. In this sense, further studies should assess the genuine effects of SARS-CoV-2 infection during pregnancy and delivery along with an extended follow-up of the offspring, including neurocognitive, neuroimaging, and electrophysiological examination. It also remains to be determined whether and by which mechanisms SARS-CoV-2 intrauterine and early life infection could lead to an increased risk of developing neuropsychiatric disorders, such as autism (ASD) and schizophrenia (SZ), in the offspring.


Assuntos
Transtorno do Espectro Autista/epidemiologia , COVID-19/epidemiologia , Síndrome da Liberação de Citocina/epidemiologia , Transtornos do Neurodesenvolvimento/epidemiologia , Complicações Infecciosas na Gravidez/epidemiologia , Efeitos Tardios da Exposição Pré-Natal/epidemiologia , Esquizofrenia/epidemiologia , Transtorno do Espectro Autista/imunologia , Encéfalo/embriologia , Encéfalo/imunologia , COVID-19/imunologia , Síndrome da Liberação de Citocina/imunologia , Feminino , Humanos , Transmissão Vertical de Doenças Infecciosas , Transtornos do Neurodesenvolvimento/imunologia , Gravidez , Complicações Infecciosas na Gravidez/imunologia , Efeitos Tardios da Exposição Pré-Natal/imunologia , Fatores de Risco , SARS-CoV-2 , Esquizofrenia/imunologia
7.
Development ; 148(19)2021 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-34608934

RESUMO

Huntington's disease (HD) is a fatal neurodegenerative disorder caused by an expansion of the CAG repeats in the huntingtin gene (HTT). Although HD has been shown to have a developmental component, how early during human embryogenesis the HTT-CAG expansion can cause embryonic defects remains unknown. Here, we demonstrate a specific and highly reproducible CAG length-dependent phenotypic signature in a synthetic model for human gastrulation derived from human embryonic stem cells (hESCs). Specifically, we observed a reduction in the extension of the ectodermal compartment that is associated with enhanced activin signaling. Surprisingly, rather than a cell-autonomous effect, tracking the dynamics of TGFß signaling demonstrated that HTT-CAG expansion perturbs the spatial restriction of activin response. This is due to defects in the apicobasal polarization in the context of the polarized epithelium of the 2D gastruloid, leading to ectopic subcellular localization of TGFß receptors. This work refines the earliest developmental window for the prodromal phase of HD to the first 2 weeks of human development, as modeled by our 2D gastruloids.


Assuntos
Linhagem da Célula , Polaridade Celular , Camadas Germinativas/metabolismo , Células-Tronco Embrionárias Humanas/metabolismo , Proteína Huntingtina/metabolismo , Ativinas/metabolismo , Animais , Linhagem Celular , Células Cultivadas , Células Epiteliais/citologia , Células Epiteliais/metabolismo , Camadas Germinativas/citologia , Camadas Germinativas/embriologia , Células-Tronco Embrionárias Humanas/citologia , Humanos , Proteína Huntingtina/genética , Camundongos , Transdução de Sinais , Fator de Crescimento Transformador beta/metabolismo , Expansão das Repetições de Trinucleotídeos
8.
Development ; 148(19)2021 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-34610637

RESUMO

Many developmental disorders are thought to arise from an interaction between genetic and environmental risk factors. The Hedgehog (HH) signaling pathway regulates myriad developmental processes, and pathway inhibition is associated with birth defects, including holoprosencephaly (HPE). Cannabinoids are HH pathway inhibitors, but little is known of their effects on HH-dependent processes in mammalian embryos, and their mechanism of action is unclear. We report that the psychoactive cannabinoid Δ9-tetrahydrocannabinol (THC) induces two hallmark HH loss-of-function phenotypes (HPE and ventral neural tube patterning defects) in Cdon mutant mice, which have a subthreshold deficit in HH signaling. THC therefore acts as a 'conditional teratogen', dependent on a complementary but insufficient genetic insult. In vitro findings indicate that THC is a direct inhibitor of the essential HH signal transducer smoothened. The canonical THC receptor, cannabinoid receptor-type 1, is not required for THC to inhibit HH signaling. Cannabis consumption during pregnancy may contribute to a combination of risk factors underlying specific developmental disorders. These findings therefore have significant public health relevance.


Assuntos
Padronização Corporal/efeitos dos fármacos , Agonistas de Receptores de Canabinoides/toxicidade , Dronabinol/toxicidade , Holoprosencefalia/induzido quimicamente , Receptor Smoothened/metabolismo , Teratógenos/toxicidade , Animais , Agonistas de Receptores de Canabinoides/farmacologia , Moléculas de Adesão Celular/genética , Células Cultivadas , Dronabinol/farmacologia , Feminino , Camundongos , Camundongos Endogâmicos C57BL , Tubo Neural/efeitos dos fármacos , Tubo Neural/embriologia , Tubo Neural/metabolismo , Transdução de Sinais/efeitos dos fármacos , Teratógenos/farmacologia
9.
Elife ; 102021 10 13.
Artigo em Inglês | MEDLINE | ID: mdl-34643182

RESUMO

The gene regulatory networks that coordinate the development of the cardiac and pulmonary systems are essential for terrestrial life but poorly understood. The T-box transcription factor Tbx5 is critical for both pulmonary specification and heart development, but how these activities are mechanistically integrated remains unclear. Here using Xenopus and mouse embryos, we establish molecular links between Tbx5 and retinoic acid (RA) signaling in the mesoderm and between RA signaling and sonic hedgehog expression in the endoderm to unveil a conserved RA-Hedgehog-Wnt signaling cascade coordinating cardiopulmonary (CP) development. We demonstrate that Tbx5 directly maintains expression of aldh1a2, the RA-synthesizing enzyme, in the foregut lateral plate mesoderm via an evolutionarily conserved intronic enhancer. Tbx5 promotes posterior second heart field identity in a positive feedback loop with RA, antagonizing a Fgf8-Cyp regulatory module to restrict FGF activity to the anterior. We find that Tbx5/Aldh1a2-dependent RA signaling directly activates shh transcription in the adjacent foregut endoderm through a conserved MACS1 enhancer. Hedgehog signaling coordinates with Tbx5 in the mesoderm to activate expression of wnt2/2b, which induces pulmonary fate in the foregut endoderm. These results provide mechanistic insight into the interrelationship between heart and lung development informing CP evolution and birth defects.


Assuntos
Família Aldeído Desidrogenase 1/genética , Regulação da Expressão Gênica no Desenvolvimento , Redes Reguladoras de Genes , Coração/embriologia , Pulmão/embriologia , Retinal Desidrogenase/genética , Proteínas com Domínio T/genética , Proteínas de Xenopus/genética , Xenopus/embriologia , Família Aldeído Desidrogenase 1/metabolismo , Animais , Sequência de Bases , Mesoderma/embriologia , Camundongos , Retinal Desidrogenase/metabolismo , Alinhamento de Sequência , Proteínas com Domínio T/metabolismo , Xenopus/genética , Xenopus/metabolismo , Proteínas de Xenopus/metabolismo , Xenopus laevis/genética , Xenopus laevis/metabolismo
10.
Int J Mol Sci ; 22(19)2021 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-34638956

RESUMO

NANOG is a key transcription factor required for maintaining pluripotency of embryonic stem cells. Elevated NANOG expression levels have been reported in many types of human cancers, including lung, oral, prostate, stomach, breast, and brain. Several studies reported the correlation between NANOG expression and tumor metastasis, revealing itself as a powerful biomarker of poor prognosis. However, how NANOG regulates tumor progression is still not known. We previously showed in medaka fish that Nanog regulates primordial germ cell migration through Cxcr4b, a chemokine receptor known for its ability to promote migration and metastasis in human cancers. Therefore, we investigated the role of human NANOG in CXCR4-mediated cancer cell migration. Of note, we found that NANOG regulatory elements in the CXCR4 promoter are functionally conserved in medaka fish and humans, suggesting an evolutionary conserved regulatory axis. Moreover, CXCR4 expression requires NANOG in human glioblastoma cells. In addition, transwell assays demonstrated that NANOG regulates cancer cell migration through the SDF1/CXCR4 pathway. Altogether, our results uncover NANOG-CXCR4 as a novel pathway controlling cellular migration and support Nanog as a potential therapeutic target in the treatment of Nanog-dependent tumor progression.


Assuntos
Neoplasias Encefálicas/metabolismo , Movimento Celular/genética , Quimiocina CXCL12/metabolismo , Glioblastoma/metabolismo , Proteína Homeobox Nanog/metabolismo , Receptores CXCR4/metabolismo , Transdução de Sinais/genética , Animais , Neoplasias Encefálicas/patologia , Linhagem Celular Tumoral , Técnicas de Silenciamento de Genes , Glioblastoma/patologia , Células HEK293 , Humanos , Proteína Homeobox Nanog/genética , Oryzias/embriologia , Regiões Promotoras Genéticas , Transfecção
11.
Int J Mol Sci ; 22(19)2021 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-34638970

RESUMO

Cardiovascular disease (CVD) is a common disease caused by many factors, including atherosclerosis, congenital heart disease, heart failure, and ischemic cardiomyopathy. CVD has been regarded as one of the most common diseases and has a severe impact on the life quality of patients. The main features of CVD include high morbidity and mortality, which seriously threaten human health. SUMO proteins covalently conjugate lysine residues with a large number of substrate proteins, and SUMOylation regulates the function of target proteins and participates in cellular activities. Under certain pathological conditions, SUMOylation of proteins related to cardiovascular development and function are greatly changed. Numerous studies have suggested that SUMOylation of substrates plays critical roles in normal cardiovascular development and function. We reviewed the research progress of SUMOylation in cardiovascular development and function, and the regulation of protein SUMOylation may be applied as a potential therapeutic strategy for CVD treatment.


Assuntos
Doenças Cardiovasculares/metabolismo , Proteínas Modificadoras Pequenas Relacionadas à Ubiquitina/metabolismo , Sumoilação , Animais , Doenças Cardiovasculares/tratamento farmacológico , Cisteína Endopeptidases/metabolismo , Coração/embriologia , Humanos , Lisina/metabolismo , Terapia de Alvo Molecular/métodos , Organogênese , Transdução de Sinais/efeitos dos fármacos , Sumoilação/efeitos dos fármacos , Enzimas de Conjugação de Ubiquitina/metabolismo
12.
Nature ; 598(7879): 174-181, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34616072

RESUMO

Dendritic and axonal morphology reflects the input and output of neurons and is a defining feature of neuronal types1,2, yet our knowledge of its diversity remains limited. Here, to systematically examine complete single-neuron morphologies on a brain-wide scale, we established a pipeline encompassing sparse labelling, whole-brain imaging, reconstruction, registration and analysis. We fully reconstructed 1,741 neurons from cortex, claustrum, thalamus, striatum and other brain regions in mice. We identified 11 major projection neuron types with distinct morphological features and corresponding transcriptomic identities. Extensive projectional diversity was found within each of these major types, on the basis of which some types were clustered into more refined subtypes. This diversity follows a set of generalizable principles that govern long-range axonal projections at different levels, including molecular correspondence, divergent or convergent projection, axon termination pattern, regional specificity, topography, and individual cell variability. Although clear concordance with transcriptomic profiles is evident at the level of major projection type, fine-grained morphological diversity often does not readily correlate with transcriptomic subtypes derived from unsupervised clustering, highlighting the need for single-cell cross-modality studies. Overall, our study demonstrates the crucial need for quantitative description of complete single-cell anatomy in cell-type classification, as single-cell morphological diversity reveals a plethora of ways in which different cell types and their individual members may contribute to the configuration and function of their respective circuits.


Assuntos
Encéfalo/citologia , Forma Celular , Neurônios/classificação , Neurônios/metabolismo , Análise de Célula Única , Atlas como Assunto , Biomarcadores/metabolismo , Encéfalo/anatomia & histologia , Encéfalo/embriologia , Encéfalo/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Humanos , Neocórtex/anatomia & histologia , Neocórtex/citologia , Neocórtex/embriologia , Neocórtex/metabolismo , Neurogênese , Neuroglia/citologia , Neurônios/citologia , RNA-Seq , Reprodutibilidade dos Testes
13.
Int J Mol Sci ; 22(19)2021 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-34638590

RESUMO

Meningiomas represent a phenotypically and genetically diverse group of tumors which often behave in ways that are not simply explained by their pathologic grade. The genetic landscape of meningiomas has become a target of investigation as tumor genomics have been found to impact tumor location, recurrence risk, and malignant potential. Additionally, targeted therapies are being developed that in the future may provide patients with personalized chemotherapy based on the genetic aberrations within their tumor. This review focuses on the most common genetic mutations found in meningiomas of all grades, with an emphasis on the impact on tumor location and clinically relevant tumor characteristics. NF-2 and the non-NF-2 family of genetic mutations are summarized in the context of low-grade and high-grade tumors, followed by a comprehensive discussion regarding the genetic and embryologic basis for meningioma location and phenotypic heterogeneity. Finally, targeted therapies based on tumor genomics currently in use and under investigation are reviewed and future avenues for research are suggested. The field of meningioma genomics has broad implications on the way meningiomas will be treated in the future, and is gradually shifting the way clinicians approach this diverse group of tumors.


Assuntos
Biomarcadores Tumorais/genética , Neoplasias Meníngeas/genética , Meningioma/genética , Animais , Heterogeneidade Genética , Genômica , Humanos , Neoplasias Meníngeas/tratamento farmacológico , Neoplasias Meníngeas/embriologia , Meningioma/tratamento farmacológico , Meningioma/embriologia , Terapia de Alvo Molecular/métodos
14.
Elife ; 102021 10 11.
Artigo em Inglês | MEDLINE | ID: mdl-34632981

RESUMO

Gut enzymes can metabolize plant defense compounds and thereby affect the growth and fitness of insect herbivores. Whether these enzymes also influence feeding preference is largely unknown. We studied the metabolization of taraxinic acid ß-D-glucopyranosyl ester (TA-G), a sesquiterpene lactone of the common dandelion (Taraxacum officinale) that deters its major root herbivore, the common cockchafer larva (Melolontha melolontha). We have demonstrated that TA-G is rapidly deglucosylated and conjugated to glutathione in the insect gut. A broad-spectrum M. melolontha ß-glucosidase, Mm_bGlc17, is sufficient and necessary for TA-G deglucosylation. Using cross-species RNA interference, we have shown that Mm_bGlc17 reduces TA-G toxicity. Furthermore, Mm_bGlc17 is required for the preference of M. melolontha larvae for TA-G-deficient plants. Thus, herbivore metabolism modulates both the toxicity and deterrence of a plant defense compound. Our work illustrates the multifaceted roles of insect digestive enzymes as mediators of plant-herbivore interactions.


Assuntos
Besouros/enzimologia , Glucosídeos/metabolismo , Herbivoria , Proteínas de Insetos/metabolismo , Lactonas/metabolismo , Sesquiterpenos/metabolismo , Taraxacum/metabolismo , beta-Galactosidase/metabolismo , Animais , Besouros/embriologia , Besouros/genética , Digestão , Glucosídeos/toxicidade , Glutationa/metabolismo , Hidrólise , Inativação Metabólica , Proteínas de Insetos/genética , Lactonas/toxicidade , Larva/enzimologia , Larva/genética , Metabolismo Secundário , Sesquiterpenos/toxicidade , Taraxacum/toxicidade , beta-Galactosidase/genética
15.
Elife ; 102021 10 12.
Artigo em Inglês | MEDLINE | ID: mdl-34636720

RESUMO

Associative learning allows animals to use past experience to predict future events. The circuits underlying memory formation support immediate and sustained changes in function, often in response to a single example. Larval Drosophila is a genetic model for memory formation that can be accessed at molecular, synaptic, cellular, and circuit levels, often simultaneously, but existing behavioral assays for larval learning and memory do not address individual animals, and it has been difficult to form long-lasting memories, especially those requiring synaptic reorganization. We demonstrate a new assay for learning and memory capable of tracking the changing preferences of individual larvae. We use this assay to explore how activation of a pair of reward neurons changes the response to the innately aversive gas carbon dioxide (CO2). We confirm that when coupled to CO2 presentation in appropriate temporal sequence, optogenetic reward reduces avoidance of CO2. We find that learning is switch-like: all-or-none and quantized in two states. Memories can be extinguished by repeated unrewarded exposure to CO2 but are stabilized against extinction by repeated training or overnight consolidation. Finally, we demonstrate long-lasting protein synthesis dependent and independent memory formation.


Assuntos
Aprendizagem por Associação , Aprendizagem da Esquiva , Comportamento Animal , Drosophila melanogaster/fisiologia , Memória , Animais , Animais Geneticamente Modificados , Dióxido de Carbono , Proteínas de Drosophila/biossíntese , Proteínas de Drosophila/genética , Drosophila melanogaster/embriologia , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Extinção Psicológica , Larva/genética , Larva/metabolismo , Larva/fisiologia , Odorantes , Percepção Olfatória , Optogenética , Recompensa , Olfato , Fatores de Tempo
16.
Elife ; 102021 10 04.
Artigo em Inglês | MEDLINE | ID: mdl-34605405

RESUMO

PERK is an endoplasmic reticulum (ER) transmembrane sensor that phosphorylates eIF2α to initiate the Unfolded Protein Response (UPR). eIF2α phosphorylation promotes stress-responsive gene expression most notably through the transcription factor ATF4 that contains a regulatory 5' leader. Possible PERK effectors other than ATF4 remain poorly understood. Here, we report that the bZIP transcription factor Xrp1 is required for ATF4-independent PERK signaling. Cell-type-specific gene expression profiling in Drosophila indicated that delta-family glutathione-S-transferases (gstD) are prominently induced by the UPR-activating transgene Rh1G69D. Perk was necessary and sufficient for such gstD induction, but ATF4 was not required. Instead, Perk and other regulators of eIF2α phosphorylation regulated Xrp1 protein levels to induce gstDs. The Xrp1 5' leader has a conserved upstream Open Reading Frame (uORF) analogous to those that regulate ATF4 translation. The gstD-GFP reporter induction required putative Xrp1 binding sites. These results indicate that antioxidant genes are highly induced by a previously unrecognized UPR signaling axis consisting of PERK and Xrp1.


Assuntos
Antioxidantes/metabolismo , Proteínas de Ligação a DNA/metabolismo , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/enzimologia , Glutationa Transferase/metabolismo , Discos Imaginais/enzimologia , eIF-2 Quinase/metabolismo , Animais , Animais Geneticamente Modificados , Sítios de Ligação , Proteínas de Ligação a DNA/genética , Proteínas de Drosophila/genética , Drosophila melanogaster/embriologia , Drosophila melanogaster/genética , Estresse do Retículo Endoplasmático , Fator de Iniciação 2 em Eucariotos/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Glutationa Transferase/genética , Discos Imaginais/embriologia , Fases de Leitura Aberta , Fosforilação , Rodopsina/genética , Rodopsina/metabolismo , Transdução de Sinais , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Resposta a Proteínas não Dobradas , eIF-2 Quinase/genética
17.
Photochem Photobiol Sci ; 20(10): 1273-1285, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34647278

RESUMO

Sunscreen safety and efficacy is generally evaluated based upon the properties of the individual chemicals in a formulation. However, the photostability of sunscreens has been shown to be highly dependent on the mixture of chemicals present. To better understand how sunscreen formulation influences stability, and to establish a foundation for probing the influence of zinc oxide additives, we formulated five different small-molecule based ultraviolet-filter (UV-filter) mixtures with a Sun Protection Factor (SPF) of 15. These mixtures contained active ingredients approved in either the United States or European Union and were designed to represent formulations of actual products on the market. We evaluated the photostability and toxicity of these mixtures in the absence and presence of zinc oxide after UV exposure for two hours. Changes in UV absorbance were minimal for all five small-molecule-based mixtures without zinc oxide. The presence of either micro- or nano-sized zinc oxide caused significant small-molecule photodegradation and the degraded mixtures exhibited higher levels of toxicity in embryonic zebrafish assays. This study suggests that caution must be taken when formulating sunscreens containing both zinc oxide and small-molecule UV-filters to avoid unintended consequences during use.


Assuntos
Protetores Solares/farmacologia , Protetores Solares/toxicidade , Raios Ultravioleta , Óxido de Zinco/farmacologia , Óxido de Zinco/toxicidade , Animais , Tamanho da Partícula , Protetores Solares/química , Peixe-Zebra/embriologia , Óxido de Zinco/química
18.
Molecules ; 26(20)2021 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-34684803

RESUMO

Honey is prone to be adulterated through mixing with sugars, cheap and low-quality honey, and other adulterants. Consumption of adulterated honey may cause several health issues such as weight gain, diabetes, and liver and kidney dysfunction. Therefore, studying the impact of consumption of adulterated honey on consumers is critical since there is a lack of study in this field. Hence, the aims of this paper were: (1) to determine the lethal concentration (LC50) of adulterated honey using zebrafish embryo, (2) to elucidate toxicology of selected adulterated honey based on lethal dose (LD50) using adult zebrafish, (3) to determine the effects of adulterated honey on histological changes of zebrafish, and (4) to screen the metabolites profile of adulterated honey by using zebrafish blood serum. The LC50 of Heterotrigona itama honey (acacia honey) and its sugar adulterants (light corn sugar, cane sugar, inverted sugar, and palm sugar in the proportion of 1-3% (w/w) from the total volume) was determined by the toxicological assessment of honey samples on zebrafish embryos (different exposure concentrations in 24, 48, 72, and 96 h postfertilization (hpf)). Pure H. itama honey represents the LC50 of 34.40 ± 1.84 (mg/mL) at 96 hpf, while the inverted sugar represents the lowest LC50 (5.03 ± 0.92 mg/mL) among sugar adulterants. The highest concentration (3%) of sugar adulterants were used to study the toxicology of adulterated honey using adult zebrafish in terms of acute, prolong-acute, and sub-acute tests. The results of the LD50 from the sub-acute toxicity test of pure H. itama honey was 2.33 ± 0.24 (mg/mL). The histological studies of internal organs showed a lesion in the liver, kidney, and spleen of adulterated treated-honey groups compared to the control group. Furthermore, the LC-MS/MS results revealed three endogenous metabolites in both the pure and adulterated honey treated groups, as follows: (1) S-Cysteinosuccinic acid, (2) 2,3-Diphosphoglyceric acid, and (3) Cysteinyl-Tyrosine. The results of this study demonstrated that adulterated honey caused mortality, which contributes to higher toxicity, and also suggested that the zebrafish toxicity test could be a standard method for assessing the potential toxicity of other hazardous food additives. The information gained from this research will permit an evaluation of the potential risk associated with the consumption of adulterated compared to pure honey.


Assuntos
Acacia/química , Contaminação de Alimentos/análise , Mel/análise , Mel/toxicidade , Açúcares/análise , Açúcares/toxicidade , Animais , Abelhas , Humanos , Rim/efeitos dos fármacos , Rim/patologia , Dose Letal Mediana , Fígado/efeitos dos fármacos , Fígado/patologia , Malásia , Metaboloma , Baço/efeitos dos fármacos , Baço/patologia , Espectrometria de Massas em Tandem , Testes de Toxicidade Aguda/métodos , Peixe-Zebra/sangue , Peixe-Zebra/embriologia
19.
PLoS One ; 16(9): e0257073, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34495967

RESUMO

BACKGROUND: Pyridoxine-dependent epilepsy (PDE) is due to biallelic variants in ALDH7A1 (PDE-ALDH7A1). ALDH7A1 encodes α-aminoadipic semialdehyde dehydrogenase in lysine catabolism. We investigated the gamma aminobutyric acid (GABA) metabolism and energy production pathways in human PDE-ALDH7A1 and its knock-out aldh7a1 zebrafish model. METHODS: We measured GABA pathway, and tricarboxylic acid cycle metabolites and electron transport chain activities in patients with PDE-ALDH7A1 and in knock-out aldh7a1 zebrafish. RESULTS: We report results of three patients with PDE-ALDH7A1: low paired complex I+II and complex II+III and individual complex IV activities in muscle biopsy in patient 1 (likely more severe phenotype); significantly elevated CSF glutamate in the GABA pathway and elevated CSF citrate, succinate, isocitrate and α-ketoglutarate in the TCA cycle in patient 3 (likely more severe phenotype); and normal CSF GABA pathway and TCA cycle metabolites on long-term pyridoxine therapy in patient 2 (likely milder phenotype). All GABA pathway metabolites (γ-hydroxybutyrate, glutamine, glutamate, total GABA, succinic semialdehyde) and TCA cycle metabolites (citrate, malate, fumarate, isocitrate, lactate) were significantly low in the homozygous knock-out aldh7a1 zebrafish compared to the wildtype zebrafish. Homozygous knock-out aldh7a1 zebrafish had decreased electron transport chain enzyme activities compared to wildtype zebrafish. DISCUSSION: We report impaired electron transport chain function, accumulation of glutamate in the central nervous system and TCA cycle dysfunction in human PDE-ALDH7A1 and abnormal GABA pathway, TCA cycle and electron transport chain in knock-out aldh7a1 zebrafish. Central nervous system glutamate toxicity and impaired energy production may play important roles in the disease neuropathogenesis and severity in human PDE-ALDH7A1.


Assuntos
Aldeído Desidrogenase/genética , Alelos , Metabolismo Energético , Epilepsia/metabolismo , Proteínas de Peixe-Zebra/genética , Animais , Ciclo do Ácido Cítrico , DNA Mitocondrial/genética , Transporte de Elétrons , Embrião não Mamífero , Metabolismo Energético/genética , Peixe-Zebra/embriologia
20.
Elife ; 102021 09 14.
Artigo em Inglês | MEDLINE | ID: mdl-34519267

RESUMO

We developed an Xrcc4M61R separation of function mouse line to overcome the embryonic lethality of Xrcc4-deficient mice. XRCC4M61R protein does not interact with Xlf, thus obliterating XRCC4-Xlf filament formation while preserving the ability to stabilize DNA ligase IV. X4M61R mice, which are DNA repair deficient, phenocopy the Nhej1-/- (known as Xlf -/-) setting with a minor impact on the development of the adaptive immune system. The core non-homologous end-joining (NHEJ) DNA repair factor XRCC4 is therefore not mandatory for V(D)J recombination aside from its role in stabilizing DNA ligase IV. In contrast, Xrcc4M61R mice crossed on Paxx-/-, Nhej1-/-, or Atm-/- backgrounds are severely immunocompromised, owing to aborted V(D)J recombination as in Xlf-Paxx and Xlf-Atm double Knock Out (DKO) settings. Furthermore, massive apoptosis of post-mitotic neurons causes embryonic lethality of Xrcc4M61R -Nhej1-/- double mutants. These in vivo results reveal new functional interplays between XRCC4 and PAXX, ATM and Xlf in mouse development and provide new insights into the understanding of the clinical manifestations of human XRCC4-deficient condition, in particular its absence of immune deficiency.


Assuntos
Reparo do DNA por Junção de Extremidades , Proteínas de Ligação a DNA/genética , Linfócitos/imunologia , Mutação de Sentido Incorreto , Imunodeficiência Combinada Severa/genética , Recombinação V(D)J , Animais , Apoptose , Proteínas Mutadas de Ataxia Telangiectasia/genética , Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Encéfalo/embriologia , Encéfalo/metabolismo , DNA Ligase Dependente de ATP/genética , DNA Ligase Dependente de ATP/metabolismo , Proteínas de Ligação a DNA/metabolismo , Modelos Animais de Doenças , Predisposição Genética para Doença , Humanos , Linfócitos/metabolismo , Camundongos Endogâmicos C57BL , Camundongos Knockout , Neurônios/metabolismo , Neurônios/patologia , Fenótipo , Imunodeficiência Combinada Severa/imunologia , Imunodeficiência Combinada Severa/metabolismo
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