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1.
EMBO J ; 42(17): e113415, 2023 09 04.
Artigo em Inglês | MEDLINE | ID: mdl-37485728

RESUMO

The human ABC transporter ABCC3 (also known as MRP3) transports a wide spectrum of substrates, including endogenous metabolites and exogenous drugs. Accordingly, it participates in multiple physiological processes and is involved in diverse human diseases such as intrahepatic cholestasis of pregnancy, which is caused by the intracellular accumulation of bile acids and estrogens. Here, we report three cryogenic electron microscopy structures of ABCC3: in the apo-form and in complexed forms bound to either the conjugated sex hormones ß-estradiol 17-(ß-D-glucuronide) and dehydroepiandrosterone sulfate. For both hormones, the steroid nuclei that superimpose against each other occupy the hydrophobic center of the transport cavity, whereas the two conjugation groups are separated and fixed by the hydrophilic patches in two transmembrane domains. Structural analysis combined with site-directed mutagenesis and ATPase activity assays revealed that ABCC3 possesses an amphiphilic substrate-binding pocket able to hold either conjugated hormone in an asymmetric pattern. These data build on consensus features of the substrate-binding pocket of MRPs and provide a structural platform for the rational design of inhibitors.


Assuntos
Transportadores de Cassetes de Ligação de ATP , Estradiol , Humanos , Transportadores de Cassetes de Ligação de ATP/genética , Estradiol/farmacologia , Estradiol/metabolismo , Mutagênese Sítio-Dirigida
2.
PLoS Pathog ; 20(9): e1012533, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39231185

RESUMO

The body temperature of Warm-blooded hosts impedes and informs responses of bacteria accustomed to cooler environments. The second messenger c-di-GMP modulates bacterial behavior in response to diverse, yet largely undiscovered, stimuli. A long-standing debate persists regarding whether a local or a global c-di-GMP pool plays a critical role. Our research on a Stenotrophomonas maltophilia strain thriving at around 28°C, showcases BtsD as a thermosensor, diguanylate cyclase, and effector. It detects 37°C and diminishes c-di-GMP synthesis, resulting in a responsive sequence: the periplasmic c-di-GMP level is decreased, the N-terminal region of BtsD disengages from c-di-GMP, activates the two-component signal transduction system BtsKR, and amplifies sod1-3 transcription, thereby strengthening the bacterium's pathogenicity and adaptation during infections in 37°C warm Galleria mellonella larvae. This revelation of a single-protein c-di-GMP module introduces unrecognized dimensions to the functional and structural paradigms of c-di-GMP modules and reshapes our understanding of bacterial adaptation and pathogenicity in hosts with a body temperature around 37°C. Furthermore, the discovery of a periplasmic c-di-GMP pool governing BtsD-BtsK interactions supports the critical role of a local c-di-GMP pool.


Assuntos
Proteínas de Bactérias , GMP Cíclico , Infecções por Bactérias Gram-Negativas , Stenotrophomonas maltophilia , Stenotrophomonas maltophilia/metabolismo , GMP Cíclico/análogos & derivados , GMP Cíclico/metabolismo , Animais , Infecções por Bactérias Gram-Negativas/microbiologia , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/genética , Transdução de Sinais , Temperatura Corporal/fisiologia , Regulação Bacteriana da Expressão Gênica , Fósforo-Oxigênio Liases/metabolismo , Fósforo-Oxigênio Liases/genética
3.
Cell ; 146(6): 1029-41, 2011 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-21925323

RESUMO

During germ cell and preimplantation development, mammalian cells undergo nearly complete reprogramming of DNA methylation patterns. We profiled the methylomes of human and chimp sperm as a basis for comparison to methylation patterns of ESCs. Although the majority of promoters escape methylation in both ESCs and sperm, the corresponding hypomethylated regions show substantial structural differences. Repeat elements are heavily methylated in both germ and somatic cells; however, retrotransposons from several subfamilies evade methylation more effectively during male germ cell development, whereas other subfamilies show the opposite trend. Comparing methylomes of human and chimp sperm revealed a subset of differentially methylated promoters and strikingly divergent methylation in retrotransposon subfamilies, with an evolutionary impact that is apparent in the underlying genomic sequence. Thus, the features that determine DNA methylation patterns differ between male germ cells and somatic cells, and elements of these features have diverged between humans and chimpanzees.


Assuntos
Metilação de DNA , Epigênese Genética , Pan troglodytes/genética , Animais , Centrômero/metabolismo , Células-Tronco Embrionárias/metabolismo , Genômica , Humanos , Masculino , Primatas/genética , Regiões Promotoras Genéticas , Espermatozoides/metabolismo
4.
Nature ; 583(7815): 282-285, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32218527

RESUMO

The ongoing outbreak of viral pneumonia in China and across the world is associated with a new coronavirus, SARS-CoV-21. This outbreak has been tentatively associated with a seafood market in Wuhan, China, where the sale of wild animals may be the source of zoonotic infection2. Although bats are probable reservoir hosts for SARS-CoV-2, the identity of any intermediate host that may have facilitated transfer to humans is unknown. Here we report the identification of SARS-CoV-2-related coronaviruses in Malayan pangolins (Manis javanica) seized in anti-smuggling operations in southern China. Metagenomic sequencing identified pangolin-associated coronaviruses that belong to two sub-lineages of SARS-CoV-2-related coronaviruses, including one that exhibits strong similarity in the receptor-binding domain to SARS-CoV-2. The discovery of multiple lineages of pangolin coronavirus and their similarity to SARS-CoV-2 suggests that pangolins should be considered as possible hosts in the emergence of new coronaviruses and should be removed from wet markets to prevent zoonotic transmission.


Assuntos
Betacoronavirus/genética , Betacoronavirus/isolamento & purificação , Eutérios/virologia , Evolução Molecular , Genoma Viral/genética , Homologia de Sequência do Ácido Nucleico , Sequência de Aminoácidos , Animais , Betacoronavirus/química , Betacoronavirus/classificação , COVID-19 , China/epidemiologia , Quirópteros/virologia , Infecções por Coronavirus/epidemiologia , Infecções por Coronavirus/transmissão , Infecções por Coronavirus/virologia , Reservatórios de Doenças/virologia , Genômica , Humanos , Malásia , Pandemias , Filogenia , Pneumonia Viral/epidemiologia , Pneumonia Viral/transmissão , Pneumonia Viral/virologia , Recombinação Genética , SARS-CoV-2 , Alinhamento de Sequência , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/genética , Zoonoses/virologia
5.
J Biol Chem ; 300(1): 105522, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38043798

RESUMO

Notch signaling plays a critical role in cell fate decisions in all cell types. Furthermore, gain-of-function mutations in NOTCH1 have been uncovered in many human cancers. Disruption of Notch signaling has recently emerged as an attractive disease treatment strategy. However, the nuclear interaction landscape of the oncoprotein NOTCH1 remains largely unexplored. We therefore employed here a proximity-dependent biotin identification approach to identify in vivo protein associations with the nuclear Notch1 intracellular domain in live cells. We identified a large set of previously reported and unreported proteins that associate with NOTCH1, including general transcription and elongation factors, DNA repair and replication factors, coactivators, corepressors, and components of the NuRD and SWI/SNF chromatin remodeling complexes. We also found that Notch1 intracellular domain associates with protein modifiers and components of other signaling pathways that may influence Notch signal transduction and protein stability such as USP7. We further validated the interaction of NOTCH1 with histone deacetylase 1 or GATAD2B using protein network analysis, proximity-based ligation, in vivo cross-linking and coimmunoprecipitation assays in several Notch-addicted cancer cell lines. Through data mining, we also revealed potential drug targets for the inhibition of Notch signaling. Collectively, these results provide a valuable resource to uncover the mechanisms that fine-tune Notch signaling in tumorigenesis and inform therapeutic targets for Notch-addicted tumors.


Assuntos
Carcinogênese , Neoplasias , Proteínas Oncogênicas , Receptor Notch1 , Humanos , Diferenciação Celular , Linhagem Celular , Proteínas Oncogênicas/genética , Proteínas Oncogênicas/metabolismo , Receptor Notch1/genética , Receptor Notch1/metabolismo , Receptores Notch/metabolismo , Transdução de Sinais , Peptidase 7 Específica de Ubiquitina/metabolismo , Carcinogênese/genética , Carcinogênese/metabolismo , Neoplasias/genética , Neoplasias/metabolismo
6.
Development ; 149(8)2022 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-35333325

RESUMO

Eosinophils, best known for their role in anti-parasitic responses, have recently been shown to actively participate in tissue homeostasis and repair. Their regulation must be tightly controlled, as their absence or hyperplasia is associated with chronic disease (e.g. asthma or inflammatory bowel disease). In the context of skeletal muscle, eosinophils play a supportive role after acute damage. Indeed, their depletion leads to strong defects in skeletal muscle regeneration and, in the absence of eosinophil-secreted interleukin (IL) 4 and IL13, fibro-adipogenic progenitors fail to support muscle stem cell proliferation. However, the role of eosinophils in muscular dystrophy remains elusive. Although it has been shown that eosinophils are present in higher numbers in muscles from mdx mice (a mouse model for Duchenne muscular dystrophy), their depletion does not affect muscle histopathology at an early age. Here, we evaluated the impact of hyper-eosinophilia on the development of fibrofatty infiltration in aged mdx mice and found that muscle eosinophilia leads to defects in muscle homeostasis, regeneration and repair, and eventually hastens death.


Assuntos
Distrofia Muscular de Duchenne , Animais , Modelos Animais de Doenças , Eosinófilos/metabolismo , Eosinófilos/patologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos mdx , Músculo Esquelético/metabolismo , Distrofia Muscular de Duchenne/metabolismo , Distrofia Muscular de Duchenne/patologia
7.
Ann Neurol ; 2024 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-38984615

RESUMO

OBJECTIVE: To investigate the association between infections and disability worsening in people with multiple sclerosis (MS) treated with either B-cell depleting therapy (rituximab) or interferon-beta/glatiramer acetate (IFN/GA). METHODS: This cohort study spanned from 2000 to 2021, using data from the Swedish MS Registry linked to national health care registries, comprising 8,759 rituximab and 7,561 IFN/GA treatment episodes. The risk of hospital-treated infection was estimated using multivariable Cox models. The association between infections and increase in Expanded Disability Status Scale (EDSS) scores was assessed using a doubly robust generalized estimating equations model. Additionally, a piece-wise exponential model analyzed events of increased disability beyond defined cut-off values, controlling for relapses, and MRI activity. RESULTS: Compared with IFN/GA, rituximab displayed increased risk of both inpatient- and outpatient-treated infections (hazard ratio [HR], 2.08; 95% confidence interval [CI], 1.50-2.90 and HR, 1.37; 95% CI, 1.13-1.67, respectively). An inpatient-treated infection was associated with a 0.19-unit increase in EDSS (95% CI, 0.12-0.26). Degree of worsening was greatest for progressive MS, and under IFN/GA treatment, which unlike rituximab, was more commonly associated with MRI activity. After controlling for relapses and MRI activity, inpatient-treated infections were associated with disability worsening in people with relapsing-remitting MS treated with IFN/GA (HR, 2.01; 95% CI, 1.59-2.53), but not in those treated with rituximab. INTERPRETATION: Compared to IFN/GA, rituximab doubled the infection risk, but reduced the risk of subsequent disability worsening. Further, the risk of worsening after hospital-treated infection was greater with progressive MS than with relapsing-remitting MS. Infection risk should be considered to improve long term outcomes. ANN NEUROL 2024.

8.
Ann Neurol ; 2024 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-39455418

RESUMO

OBJECTIVE: The objective of this study was to investigate the association between developmental and premorbid body composition measurements and the risk of motor neuron disease (MND). METHODS: We performed a cohort study in the UK Biobank to assess the association of developmental body metrics and premorbid body composition measures (using 28 measurements and 7 patterns of body composition) with the risk of MND. Among participants with longitudinal measures, we compared the changes in body composition over time between individuals who later developed MND and those who remained free of MND. RESULTS: Among the 412,691 individuals included in this study, 549 people received an MND diagnosis during the follow-up visit. Higher birth weight was associated with an increased risk of MND among individuals born over 4 kg (hazard ratio [HR] per kg increase = 2.21, 95% confidence interval [CI] = 1.38-3.55), and taller adult height was associated with an increased risk of MND (HR per 5 cm increase = 1.10, 95% CI = 1.03-1.17). We observed that measures of elevated fat mass were associated with a lower risk of MND more than 5 years before diagnosis. A higher "leg-dominant fat distribution" pattern was associated with an increased risk whereas higher "muscle strength" was associated with a reduced risk of MND 5 years before diagnosis. Longitudinal analyses indicated a faster decline in measures of fat mass and muscle strength, as well as a shift in fat distribution from arm to leg dominant, among individuals who later developed MND, compared with others. INTERPRETATION: Body composition at early and middle age may be indicative of the risk of MND development. ANN NEUROL 2024.

9.
Plant Cell ; 34(5): 2038-2055, 2022 04 26.
Artigo em Inglês | MEDLINE | ID: mdl-35188198

RESUMO

In tomato (Solanum lycopersicum) and other plants, the photoreceptor UV-RESISTANCE LOCUS 8 regulates plant UV-B photomorphogenesis by modulating the transcription of many genes, the majority of which depends on the transcription factor ELONGATED HYPOCOTYL 5 (HY5). HY5 transcription is induced and then rapidly attenuated by UV-B. However, neither the transcription factors that activate HY5 transcription nor the mechanism for its attenuation during UV-B signaling is known. Here, we report that the tomato B-BOX (BBX) transcription factors SlBBX20 and SlBBX21 interact with SlHY5 and bind to the SlHY5 promoter to activate its transcription. UV-B-induced SlHY5 expression and SlHY5-controlled UV-B responses are normal in slbbx20 and slbbx21 single mutants, but strongly compromised in the slbbx20 slbbx21 double mutant. Surprisingly, UV-B responses are also compromised in lines overexpressing SlBBX20 or SlBBX21. Both SlHY5 and SlBBX20 bind to G-box1 in the SlHY5 promoter. SlHY5 outcompetes SlBBX20 for binding to the SlHY5 promoter in vitro, and inhibits the association of SlBBX20 with the SlHY5 promoter in vivo. Overexpressing 35S:SlHY5-FLAG in the WT background inhibits UV-B-induced endogenous SlHY5 expression. Together, our results reveal the critical role of the SlBBX20/21-SlHY5 module in activating the expression of SlHY5, the gene product of which inhibits its own gene transcription under UV-B, forming an autoregulatory negative feedback loop that balances SlHY5 transcription in plants.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Solanum lycopersicum , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Fatores de Transcrição de Zíper de Leucina Básica/metabolismo , Retroalimentação , Regulação da Expressão Gênica de Plantas/genética , Solanum lycopersicum/genética , Solanum lycopersicum/metabolismo , Fatores de Transcrição/metabolismo , Raios Ultravioleta
10.
Plant Cell ; 34(10): 3685-3701, 2022 09 27.
Artigo em Inglês | MEDLINE | ID: mdl-35775949

RESUMO

Demethylation of transposons can activate the expression of nearby genes and cause imprinted gene expression in the endosperm; this demethylation is hypothesized to lead to expression of transposon small interfering RNAs (siRNAs) that reinforce silencing in the next generation through transfer either into egg or embryo. Here we describe maize (Zea mays) maternal derepression of r1 (mdr1), which encodes a DNA glycosylase with homology to Arabidopsis thaliana DEMETER and which is partially responsible for demethylation of thousands of regions in endosperm. Instead of promoting siRNA expression in endosperm, MDR1 activity inhibits it. Methylation of most repetitive DNA elements in endosperm is not significantly affected by MDR1, with an exception of Helitrons. While maternally-expressed imprinted genes preferentially overlap with MDR1 demethylated regions, the majority of genes that overlap demethylated regions are not imprinted. Double mutant megagametophytes lacking both MDR1 and its close homolog DNG102 result in early seed failure, and double mutant microgametophytes fail pre-fertilization. These data establish DNA demethylation by glycosylases as essential in maize endosperm and pollen and suggest that neither transposon repression nor genomic imprinting is its main function in endosperm.


Assuntos
Arabidopsis , DNA Glicosilases , Arabidopsis/genética , DNA/metabolismo , DNA Glicosilases/genética , DNA Glicosilases/metabolismo , Metilação de DNA/genética , Endosperma/genética , Endosperma/metabolismo , Regulação da Expressão Gênica de Plantas/genética , Impressão Genômica/genética , RNA Interferente Pequeno/genética , Zea mays/genética , Zea mays/metabolismo
11.
FASEB J ; 38(13): e23706, 2024 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-38877842

RESUMO

The etiology of preeclampsia (PE), a complex and multifactorial condition, remains incompletely understood. DNA methylation, which is primarily regulated by three DNA methyltransferases (DNMTs), DNMT1, DNMT3A, and DNMT3B, plays a vital role in early embryonic development and trophectoderm differentiation. Yet, how DNMTs modulate trophoblast fusion and PE development remains unclear. In this study, we found that the DNMTs expression was downregulated during trophoblast cells fusion. Downregulation of DNMTs was observed during the reconstruction of the denuded syncytiotrophoblast (STB) layer of placental explants. Additionally, overexpression of DNMTs inhibited trophoblast fusion. Conversely, treatment with the DNA methylation inhibitor 5-aza-CdR decreased the expression of DNMTs and promoted trophoblast fusion. A combined analysis of DNA methylation data and gene transcriptome data obtained from the primary cytotrophoblasts (CTBs) fusion process identified 104 potential methylation-regulated differentially expressed genes (MeDEGs) with upregulated expression due to DNA demethylation, including CD59, TNFAIP3, SDC1, and CDK6. The transcription regulation region (TRR) of TNFAIP3 showed a hypomethylation with induction of 5-aza-CdR, which facilitated CREB recruitment and thereby participated in regulating trophoblast fusion. More importantly, clinical correlation analysis of PE showed that the abnormal increase in DNMTs may be involved in the development of PE. This study identified placental DNA methylation-regulated genes that may contribute to PE, offering a novel perspective on the role of epigenetics in trophoblast fusion and its implication in PE development.


Assuntos
DNA (Citosina-5-)-Metiltransferases , Metilação de DNA , Pré-Eclâmpsia , Trofoblastos , Trofoblastos/metabolismo , Feminino , Pré-Eclâmpsia/genética , Pré-Eclâmpsia/metabolismo , Pré-Eclâmpsia/patologia , Gravidez , Humanos , DNA (Citosina-5-)-Metiltransferases/genética , DNA (Citosina-5-)-Metiltransferases/metabolismo , Fusão Celular , Placenta/metabolismo , DNA (Citosina-5-)-Metiltransferase 1/metabolismo , DNA (Citosina-5-)-Metiltransferase 1/genética
12.
Mol Psychiatry ; 2024 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-38755244

RESUMO

Pre-existing psychiatric disorders were linked to an increased susceptibility to COVID-19 during the initial outbreak of the pandemic, while evidence during Omicron prevalence is lacking. Leveraging data from two prospective cohorts in China, we identified incident Omicron infections between January 2023 and April 2023. Participants with a self-reported history or self-rated symptoms of depression or anxiety before the Omicron pandemic were considered the exposed group, whereas the others were considered unexposed. We employed multivariate logistic regression models to examine the association of pre-existing depression or anxiety with the risk of any or severe Omicron infection indexed by medical interventions or severe symptoms. Further, we stratified the analyses by polygenic risk scores (PRSs) for COVID-19 and repeated the analyses using the UK Biobank data. We included 10,802 individuals from the Chinese cohorts (mean age = 51.1 years, 45.6% male), among whom 7841 (72.6%) were identified as cases of Omicron infection. No association was found between any pre-existing depression or anxiety and the overall risk of Omicron infection (odds ratio [OR] =1.04, 95% confidence interval [CI] 0.95-1.14). However, positive associations were noted for severe Omicron infection, either as infections requiring medical interventions (1.26, 1.02-1.54) or with severe symptoms (≥3: 1.73, 1.51-1.97). We obtained comparable estimates when stratified by COVID-19 PRS level. Additionally, using clustering method, we identified eight distinct symptom patterns and found associations between pre-existing depression or anxiety and the patterns characterized by multiple or complex severe symptoms including cough and taste and smell decline (ORs = 1.42-2.35). The results of the UK Biobank analyses corroborated findings of the Chinese cohorts. In conclusion, pre-existing depression and anxiety was not associated with the risk of Omicron infection overall but an elevated risk of severe Omicron infection, supporting the continued efforts on monitoring and possible early intervention in this high-risk population during Omicron prevalence.

13.
Brain ; 147(6): 1967-1974, 2024 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-38478578

RESUMO

Leigh syndrome spectrum (LSS) is a primary mitochondrial disorder defined neuropathologically by a subacute necrotizing encephalomyelopathy and characterized by bilateral basal ganglia and/or brainstem lesions. LSS is associated with variants in several mitochondrial DNA genes and more than 100 nuclear genes, most often related to mitochondrial complex I (CI) dysfunction. Rarely, LSS has been reported in association with primary Leber hereditary optic neuropathy (LHON) variants of the mitochondrial DNA, coding for CI subunits (m.3460G>A in MT-ND1, m.11778G>A in MT-ND4 and m.14484T>C in MT-ND6). The underlying mechanism by which these variants manifest as LSS, a severe neurodegenerative disease, as opposed to the LHON phenotype of isolated optic neuropathy, remains an open question. Here, we analyse the exome sequencing of six probands with LSS carrying primary LHON variants, and report digenic co-occurrence of the m.11778G > A variant with damaging heterozygous variants in nuclear disease genes encoding CI subunits as a plausible explanation. Our findings suggest a digenic mechanism of disease for m.11778G>A-associated LSS, consistent with recent reports of digenic disease in individuals manifesting with LSS due to biallelic variants in the recessive LHON-associated disease gene DNAJC30 in combination with heterozygous variants in CI subunits.


Assuntos
Doença de Leigh , Atrofia Óptica Hereditária de Leber , Humanos , Doença de Leigh/genética , Atrofia Óptica Hereditária de Leber/genética , Masculino , Feminino , Adulto , DNA Mitocondrial/genética , Complexo I de Transporte de Elétrons/genética , Criança , Adolescente , NADH Desidrogenase/genética , Mutação , Adulto Jovem , Sequenciamento do Exoma , Pré-Escolar
14.
Nature ; 569(7757): 581-585, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-31043749

RESUMO

Methylation of cytosine to 5-methylcytosine (5mC) is a prevalent DNA modification found in many organisms. Sequential oxidation of 5mC by ten-eleven translocation (TET) dioxygenases results in a cascade of additional epigenetic marks and promotes demethylation of DNA in mammals1,2. However, the enzymatic activity and function of TET homologues in other eukaryotes remains largely unexplored. Here we show that the green alga Chlamydomonas reinhardtii contains a 5mC-modifying enzyme (CMD1) that is a TET homologue and catalyses the conjugation of a glyceryl moiety to the methyl group of 5mC through a carbon-carbon bond, resulting in two stereoisomeric nucleobase products. The catalytic activity of CMD1 requires Fe(II) and the integrity of its binding motif His-X-Asp, which is conserved in Fe-dependent dioxygenases3. However, unlike previously described TET enzymes, which use 2-oxoglutarate as a co-substrate4, CMD1 uses L-ascorbic acid (vitamin C) as an essential co-substrate. Vitamin C donates the glyceryl moiety to 5mC with concurrent formation of glyoxylic acid and CO2. The vitamin-C-derived DNA modification is present in the genome of wild-type C. reinhardtii but at a substantially lower level in a CMD1 mutant strain. The fitness of CMD1 mutant cells during exposure to high light levels is reduced. LHCSR3, a gene that is critical for the protection of C. reinhardtii from photo-oxidative damage under high light conditions, is hypermethylated and downregulated in CMD1 mutant cells compared to wild-type cells, causing a reduced capacity for photoprotective non-photochemical quenching. Our study thus identifies a eukaryotic DNA base modification that is catalysed by a divergent TET homologue and unexpectedly derived from vitamin C, and describes its role as a potential epigenetic mark that may counteract DNA methylation in the regulation of photosynthesis.


Assuntos
5-Metilcitosina/metabolismo , Proteínas de Algas/metabolismo , Ácido Ascórbico/metabolismo , Biocatálise , Chlamydomonas reinhardtii/enzimologia , DNA/química , DNA/metabolismo , 5-Metilcitosina/química , Dióxido de Carbono/metabolismo , Metilação de DNA , Glioxilatos/metabolismo , Nucleosídeos/química , Nucleosídeos/metabolismo , Fotossíntese
15.
Cereb Cortex ; 34(2)2024 01 31.
Artigo em Inglês | MEDLINE | ID: mdl-38185991

RESUMO

Intracranial electrical stimulation (iES) of auditory cortex can elicit sound experiences with a variety of perceived contents (hallucination or illusion) and locations (contralateral or bilateral side), independent of actual acoustic inputs. However, the neural mechanisms underlying this elicitation heterogeneity remain undiscovered. Here, we collected subjective reports following iES at 3062 intracranial sites in 28 patients (both sexes) and identified 113 auditory cortical sites with iES-elicited sound experiences. We then decomposed the sound-induced intracranial electroencephalogram (iEEG) signals recorded from all 113 sites into time-frequency features. We found that the iES-elicited perceived contents can be predicted by the early high-γ features extracted from sound-induced iEEG. In contrast, the perceived locations elicited by stimulating hallucination sites and illusion sites are determined by the late high-γ and long-lasting α features, respectively. Our study unveils the crucial neural signatures of iES-elicited sound experiences in human and presents a new strategy to hearing restoration for individuals suffering from deafness.


Assuntos
Córtex Auditivo , Ilusões , Masculino , Feminino , Humanos , Córtex Auditivo/fisiologia , Ilusões/fisiologia , Estimulação Acústica , Mapeamento Encefálico , Estimulação Elétrica , Alucinações
16.
Cell Mol Life Sci ; 81(1): 92, 2024 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-38363375

RESUMO

The maintenance of genome integrity in the germline is crucial for mammalian development. Long interspersed element type 1 (LINE-1, L1) is a mobile genetic element that makes up about 17% of the human genome and poses a threat to genome integrity. N6-methyl-adenosine (m6A) plays an essential role in regulating various biological processes. However, the function of m6A modification in L1 retrotransposons and human germline development remains largely unknown. Here we knocked out the m6A methyltransferase METTL3 or the m6A reader YTHDF2 in human embryonic stem cells (hESCs) and discovered that METTL3 and YTHDF2 are crucial for inducing human spermatogonial stem cells (hSSCs) from hESCs in vitro. The removal of METTL3 or YTHDF2 resulted in increased L1 retrotransposition and reduced the efficiency of SSC differentiation in vitro. Further analysis showed that YTHDF2 recognizes the METTL3-catalyzed m6A modification of L1 retrotransposons and degrades L1 mRNA through autophagy, thereby blocking L1 retrotransposition. Moreover, the study confirmed that m6A modification in human fetal germ cells promotes the degradation of L1 retrotransposon RNA, preventing the insertion of new L1 retrotransposons into the genome. Interestingly, L1 retrotransposon RNA was highly expressed while METTL3 was significantly downregulated in the seminal plasma of azoospermic patients with meiotic arrest compared to males with normal fertility. Additionally, we identified some potentially pathogenic variants in m6A-related genes in azoospermic men with meiotic arrest. In summary, our study suggests that m6A modification serves as a guardian of genome stability during human germline development and provides novel insights into the function and regulatory mechanisms of m6A modification in restricting L1 retrotransposition.


Assuntos
Azoospermia , Retroelementos , Masculino , Animais , Humanos , Retroelementos/genética , RNA , Azoospermia/genética , Diferenciação Celular/genética , Metiltransferases/genética , Metiltransferases/metabolismo , RNA Mensageiro/genética , Mamíferos/metabolismo
17.
Proc Natl Acad Sci U S A ; 119(48): e2206829119, 2022 11 29.
Artigo em Inglês | MEDLINE | ID: mdl-36409915

RESUMO

Retinal ganglion cells (RGCs) are heterogeneous projection neurons that convey distinct visual features from the retina to brain. Here, we present a high-throughput in vivo RGC activity assay in response to light stimulation using noninvasive Ca2+ imaging of thousands of RGCs simultaneously in living mice. Population and single-cell analyses of longitudinal RGC Ca2+ imaging reveal distinct functional responses of RGCs and unprecedented individual RGC activity conversions during traumatic and glaucomatous degeneration. This study establishes a foundation for future in vivo RGC function classifications and longitudinal activity evaluations using more advanced imaging techniques and visual stimuli under normal, disease, and neural repair conditions. These analyses can be performed at both the population and single-cell levels using temporal and spatial information, which will be invaluable for understanding RGC pathophysiology and identifying functional biomarkers for diverse optic neuropathies.


Assuntos
Glaucoma , Células Ganglionares da Retina , Animais , Camundongos , Diagnóstico por Imagem , Retina , Glaucoma/diagnóstico por imagem , Encéfalo
18.
Eur Heart J ; 45(31): 2865-2875, 2024 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-38889798

RESUMO

BACKGROUND AND AIMS: Increasing evidence suggests that some reproductive factors/hazards are associated with a future risk of cardiovascular disease (CVD) in women. While major (non-perinatal) depression has consistently been associated with CVD, the long-term risk of CVD after perinatal depression (PND) is largely unknown. METHODS: A nationwide population-based matched cohort study involving 55 539 women diagnosed with PND during 2001-14 in Sweden and 545 567 unaffected women individually matched on age and year of conception/delivery was conducted. All women were followed up to 2020. Perinatal depression and CVD were identified from Swedish national health registers. Using multivariable Cox models, hazard ratios (HR) of any and type-specific CVD according to PND were estimated. RESULTS: The mean age at the PND diagnosis was 30.8 [standard deviation (SD) 5.6] years. During the follow-up of up to 20 years (mean 10.4, SD 3.6), 3533 (6.4%) women with PND (expected number 2077) and 20 202 (3.7%) unaffected women developed CVD. Compared with matched unaffected women, women with PND had a 36% higher risk of developing CVD [adjusted HR = 1.36, 95% confidence interval (CI): 1.31-1.42], while compared with their sisters, women with PND had a 20% higher risk of CVD (adjusted HR = 1.20, 95% CI 1.07-1.34). The results were most pronounced in women without a history of psychiatric disorder (P for interaction < .001). The association was observed for all CVD subtypes, with the highest HR in the case of hypertensive disease (HR = 1.50, 95% CI: 1.41-1.60), ischaemic heart disease (HR = 1.37, 95% CI: 1.13-1.65), and heart failure (HR 1.36, 95% CI: 1.06-1.74). CONCLUSIONS: Women with PND are at higher risk of CVD in middle adulthood. Reproductive history, including PND, should be considered in CVD risk assessments of women.


Assuntos
Doenças Cardiovasculares , Humanos , Feminino , Suécia/epidemiologia , Adulto , Doenças Cardiovasculares/epidemiologia , Gravidez , Fatores de Risco , Complicações na Gravidez/epidemiologia , Depressão/epidemiologia
19.
J Infect Dis ; 2024 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-39215587

RESUMO

Gullain-Barré syndrome (GBS) is an acute peripheral neuropathy often preceded by respiratory or gastrointestinal infections, though molecular testing of cerebrospinal fluid (CSF) is often inconclusive. In a recent case of severe pediatric GBS in British Columbia, Canada, we detected CSF antibodies against enterovirus D (EV-D) to link GBS with prior EV-D68 respiratory infection.

20.
J Neurosci ; 43(8): 1405-1413, 2023 02 22.
Artigo em Inglês | MEDLINE | ID: mdl-36690451

RESUMO

Rapid detection of a threat or its symbol (e.g., fearful face), whether visible or invisible, is critical for human survival. This function is suggested to be enabled by a subcortical pathway to the amygdala independent of the cortex. However, conclusive electrophysiological evidence in humans is scarce. Here, we explored whether the amygdala can rapidly encode invisible fearful faces. We recorded intracranial electroencephalogram (iEEG) responses in the human (both sexes) amygdala to faces with fearful, happy, and neutral emotions rendered invisible by backward masking. We found that a short-latency intracranial event-related potential (iERP) in the amygdala, beginning 88 ms poststimulus onset, was preferentially evoked by invisible fearful faces relative to invisible happy or neutral faces. The rapid iERP exhibited selectivity to the low spatial frequency (LSF) component of the fearful faces. Time-frequency iEEG analyses further identified a rapid amygdala response preferentially for LSF fearful faces at the low gamma frequency band, beginning 45 ms poststimulus onset. In contrast, these rapid responses to invisible fearful faces were absent in cortical regions, including early visual areas, the fusiform gyrus, and the parahippocampal gyrus. These findings provide direct evidence for the existence of a subcortical pathway specific for rapid fear detection in the amygdala and demonstrate that the subcortical pathway can function without conscious awareness and under minimal influence from cortical areas.SIGNIFICANCE STATEMENT Automatic detection of biologically relevant stimuli, such as threats or dangers, has remarkable survival value. Here, we provide direct intracranial electrophysiological evidence that the human amygdala preferentially responds to fearful faces at a rapid speed, despite the faces being invisible. This rapid, fear-selective response is restricted to faces containing low spatial frequency information transmitted by magnocellular neurons and does not appear in cortical regions. These results support the existence of a rapid subcortical pathway independent of cortical pathways to the human amygdala.


Assuntos
Medo , Imageamento por Ressonância Magnética , Masculino , Feminino , Humanos , Medo/fisiologia , Emoções/fisiologia , Felicidade , Tonsila do Cerebelo/fisiologia , Expressão Facial
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