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1.
Genes Dev ; 33(19-20): 1416-1427, 2019 10 01.
Artículo en Inglés | MEDLINE | ID: mdl-31488576

RESUMEN

Polycomb-repressive complex 2 (PRC2) is a histone methyltransferase that is critical for regulating transcriptional repression in mammals. Its catalytic subunit, EZH2, is responsible for the trimethylation of H3K27 and also undergoes automethylation. Using mass spectrometry analysis of recombinant human PRC2, we identified three methylated lysine residues (K510, K514, and K515) on a disordered but highly conserved loop of EZH2. Methylation of these lysines increases PRC2 histone methyltransferase activity, whereas their mutation decreases activity in vitro. De novo histone methylation in an EZH2 knockout cell line is greatly impeded by mutation of the automethylation lysines. EZH2 automethylation occurs intramolecularly (in cis) by methylation of a pseudosubstrate sequence on a flexible loop. This posttranslational modification and cis regulation of PRC2 are analogous to the activation of many protein kinases by autophosphorylation. We propose that EZH2 automethylation allows PRC2 to modulate its histone methyltransferase activity by sensing histone H3 tails, SAM concentration, and perhaps other effectors.


Asunto(s)
Histonas/metabolismo , Complejo Represivo Polycomb 2/metabolismo , Proteína Potenciadora del Homólogo Zeste 2/genética , Proteína Potenciadora del Homólogo Zeste 2/metabolismo , Activación Enzimática/fisiología , Regulación de la Expresión Génica , Humanos , Lisina/metabolismo , Metilación , Procesamiento Proteico-Postraduccional , Proteínas Recombinantes/metabolismo
2.
Proc Natl Acad Sci U S A ; 119(22): e2201883119, 2022 05 31.
Artículo en Inglés | MEDLINE | ID: mdl-35617427

RESUMEN

Polycomb-group proteins play critical roles in gene silencing through the deposition of histone H3 lysine 27 trimethylation (H3K27me3) and chromatin compaction. This process is essential for embryonic stem cell (ESC) pluripotency, differentiation, and development. Polycomb repressive complex 2 (PRC2) can both read and write H3K27me3, enabling progressive spreading of H3K27me3 on the linear genome. Long-range Polycomb-associated DNA contacts have also been described, but their regulation and role in gene silencing remain unclear. Here, we apply H3K27me3 HiChIP, a protein-directed chromosome conformation method, and optical reconstruction of chromatin architecture to profile long-range Polycomb-associated DNA loops that span tens to hundreds of megabases across multiple topological associated domains in mouse ESCs and human induced pluripotent stem cells. We find that H3K27me3 loop anchors are enriched for Polycomb nucleation points and coincide with key developmental genes. Genetic deletion of H3K27me3 loop anchors results in disruption of spatial contact between distant loci and altered H3K27me3 in cis, both locally and megabases away on the same chromosome. In mouse embryos, loop anchor deletion leads to ectopic activation of the partner gene, suggesting that Polycomb-associated loops control gene silencing during development. Further, we find that alterations in PRC2 occupancy resulting from an RNA binding­deficient EZH2 mutant are accompanied by loss of Polycomb-associated DNA looping. Together, these results suggest PRC2 uses RNA binding to enhance long-range chromosome folding and H3K27me3 spreading. Developmental gene loci have unique roles in Polycomb spreading, emerging as important architectural elements of the epigenome.


Asunto(s)
Cromosomas , Regulación del Desarrollo de la Expresión Génica , Silenciador del Gen , Histonas , Complejo Represivo Polycomb 2 , Animales , Inmunoprecipitación de Cromatina/métodos , Cromosomas/química , Cromosomas/metabolismo , Embrión de Mamíferos , Proteína Potenciadora del Homólogo Zeste 2/genética , Histonas/genética , Histonas/metabolismo , Humanos , Células Madre Pluripotentes Inducidas/metabolismo , Lisina/metabolismo , Metilación , Ratones , Conformación de Ácido Nucleico , Complejo Represivo Polycomb 2/química , Complejo Represivo Polycomb 2/metabolismo
3.
Psychol Med ; 54(3): 582-591, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-37553976

RESUMEN

BACKGROUND: The age-related heterogeneity in major depressive disorder (MDD) has received significant attention. However, the neural mechanisms underlying such heterogeneity still need further investigation. This study aimed to explore the common and distinct functional brain abnormalities across different age groups of MDD patients from a large-sample, multicenter analysis. METHODS: The analyzed sample consisted of a total of 1238 individuals including 617 MDD patients (108 adolescents, 12-17 years old; 411 early-middle adults, 18-54 years old; and 98 late adults, > = 55 years old) and 621 demographically matched healthy controls (60 adolescents, 449 early-middle adults, and 112 late adults). MDD-related abnormalities in brain functional connectivity (FC) patterns were investigated in each age group separately and using the whole pooled sample, respectively. RESULTS: We found shared FC reductions among the sensorimotor, visual, and auditory networks across all three age groups of MDD patients. Furthermore, adolescent patients uniquely exhibited increased sensorimotor-subcortical FC; early-middle adult patients uniquely exhibited decreased visual-subcortical FC; and late adult patients uniquely exhibited wide FC reductions within the subcortical, default-mode, cingulo-opercular, and attention networks. Analysis of covariance models using the whole pooled sample further revealed: (1) significant main effects of age group on FCs within most brain networks, suggesting that they are decreased with aging; and (2) a significant age group × MDD diagnosis interaction on FC within the default-mode network, which may be reflective of an accelerated aging-related decline in default-mode FCs. CONCLUSIONS: To summarize, these findings may deepen our understanding of the age-related biological and clinical heterogeneity in MDD.


Asunto(s)
Trastorno Depresivo Mayor , Adulto , Humanos , Adolescente , Niño , Adulto Joven , Persona de Mediana Edad , Imagen por Resonancia Magnética , Encéfalo/diagnóstico por imagen , Mapeo Encefálico , Corteza Insular
4.
Hum Brain Mapp ; 44(6): 2191-2208, 2023 04 15.
Artículo en Inglés | MEDLINE | ID: mdl-36637216

RESUMEN

The multilayer dynamic network model has been proposed as an effective method to understand the brain function. In particular, derived from the definition of clustering coefficient in static networks, the temporal clustering coefficient provides a direct measure of the topological stability of dynamic brain networks and shows potential in predicting altered brain functions. However, test-retest reliability and demographic-related effects on this measure remain to be evaluated. Using a data set from the Human Connectome Project (157 male and 180 female healthy adults; 22-37 years old), the present study investigated: (1) the test-retest reliability of temporal clustering coefficient across four repeated resting-state functional magnetic resonance imaging scans as measured by intraclass correlation coefficient (ICC); and (2) sex- and age-related effects on temporal clustering coefficient. The results showed that (1) the temporal clustering coefficient had overall moderate test-retest reliability (ICC > 0.40 over a wide range of densities) at both global and subnetwork levels, (2) female subjects showed significantly higher temporal clustering coefficient than males at both global and subnetwork levels, particularly within the default-mode and subcortical regions, and (3) temporal clustering coefficient of the subcortical subnetwork was positively correlated with age in young adults. The results of sex effects were robustly replicated in an independent REST-meta-MDD data set, while the results of age effects were not. Our findings suggest that the temporal clustering coefficient is a relatively reliable and reproducible approach for identifying individual differences in brain function, and provide evidence for demographically related effects on the human brain dynamic connectomes.


Asunto(s)
Conectoma , Imagen por Resonancia Magnética , Adulto Joven , Humanos , Masculino , Femenino , Adulto , Reproducibilidad de los Resultados , Imagen por Resonancia Magnética/métodos , Encéfalo/diagnóstico por imagen , Conectoma/métodos , Análisis por Conglomerados
5.
Zhong Nan Da Xue Xue Bao Yi Xue Ban ; 48(1): 76-83, 2023 Jan 28.
Artículo en Inglés, Zh | MEDLINE | ID: mdl-36935180

RESUMEN

OBJECTIVES: Magnetic resonance diffusion-weighted imaging (DWI) has important clinical value in diagnosis and curative effect evaluation on endometrial carcinoma. How to improve the detection rate of endometrial small lesions by DWI is the research focus of MRI technology. This study aims to analyze the image quality of small field MRI ZOOMit-DWI sequence and conventional single-shot echo-planar imaging (SS-EPI) DWI sequence in the scanning of endometrial carcinoma, and to explore the clinical value of ZOOMit-DWI sequence. METHODS: A total of 37 patients with endometrial carcinoma diagnosed by operation and pathology in the Second Xiangya Hospital of Central South University from July 2019 to May 2021 were collected. All patients were scanned with MRI ZOOMit-DWI sequence and SS-EPI DWI sequence before operation. Two radiologists subjectively evaluated the anatomical details, artifacts, geometric deformation and focus definition of the 2 groups of DWI images. At the same time, the signal intensity were measured and the signal-to-noise ratio (SNR), contrast to noise ratio (CNR), and apparent diffusion coefficient (ADC) of the 2 DWI sequences were calculated for objective evaluation. The differences of subjective score, objective score and ADC value of the 2 DWI sequences were analyzed. RESULTS: The SNR of the ZOOMit-DWI group was significantly higher than that of the SS-EPI DWI group (301.96±141.85 vs 94.66±41.26), and the CNR of the ZOOMit-DWI group was significantly higher than that of the SS-EPI DWI group (185.05±105.45 vs 57.91±31.54, P<0.05). There was no significant difference in noise standard deviation between the ZOOMit-DWI group and the SS-EPI DWI group (P>0.05). The subjective score of anatomical detail and focus definition in the ZOOMit-DWI group was significantly higher than that of the SS-EPI DWI group (both P<0.05). The subjective score of artifacts and geometric deformation of ZOOMit-DWI group was significantly lower than that of the SS-EPI DWI group (both P<0.05). ADC had no significant difference between the ZOOMit-DWI group and the SS-EPI DWI group (P>0.05). CONCLUSIONS: The image quality of ZOOMit-DWI is significantly higher than that of conventional SS-EPI DWI. In the MRI DWI examination of endometrial carcinoma, ZOOMit-DWI can effectively reduce the geometric deformation and artifacts of the image, which is more conducive to clinical diagnosis and treatment.


Asunto(s)
Neoplasias Endometriales , Femenino , Humanos , Relación Señal-Ruido , Neoplasias Endometriales/diagnóstico por imagen , Imagen de Difusión por Resonancia Magnética/métodos , Endometrio , Imagen Eco-Planar/métodos , Reproducibilidad de los Resultados
6.
Mol Psychiatry ; 26(12): 7363-7371, 2021 12.
Artículo en Inglés | MEDLINE | ID: mdl-34385597

RESUMEN

Aberrant topological organization of whole-brain networks has been inconsistently reported in studies of patients with major depressive disorder (MDD), reflecting limited sample sizes. To address this issue, we utilized a big data sample of MDD patients from the REST-meta-MDD Project, including 821 MDD patients and 765 normal controls (NCs) from 16 sites. Using the Dosenbach 160 node atlas, we examined whole-brain functional networks and extracted topological features (e.g., global and local efficiency, nodal efficiency, and degree) using graph theory-based methods. Linear mixed-effect models were used for group comparisons to control for site variability; robustness of results was confirmed (e.g., multiple topological parameters, different node definitions, and several head motion control strategies were applied). We found decreased global and local efficiency in patients with MDD compared to NCs. At the nodal level, patients with MDD were characterized by decreased nodal degrees in the somatomotor network (SMN), dorsal attention network (DAN) and visual network (VN) and decreased nodal efficiency in the default mode network (DMN), SMN, DAN, and VN. These topological differences were mostly driven by recurrent MDD patients, rather than first-episode drug naive (FEDN) patients with MDD. In this highly powered multisite study, we observed disrupted topological architecture of functional brain networks in MDD, suggesting both locally and globally decreased efficiency in brain networks.


Asunto(s)
Trastorno Depresivo Mayor , Encéfalo , Mapeo Encefálico , Humanos , Imagen por Resonancia Magnética/métodos , Vías Nerviosas , Tamaño de la Muestra
7.
Bipolar Disord ; 24(4): 400-411, 2022 06.
Artículo en Inglés | MEDLINE | ID: mdl-34606159

RESUMEN

BACKGROUND: Recently, functional homotopy (FH) architecture, defined as robust functional connectivity (FC) between homotopic regions, has been frequently reported to be altered in MDD patients (MDDs) but with divergent locations. METHODS: In this study, we obtained resting-state functional magnetic resonance imaging (R-fMRI) data from 1004 MDDs (mean age, 33.88 years; age range, 18-60 years) and 898 matched healthy controls (HCs) from an aggregated dataset from 20 centers in China. We focused on interhemispheric function integration in MDDs and its correlation with clinical characteristics using voxel-mirrored homotopic connectivity (VMHC) devised to inquire about FH patterns. RESULTS: As compared with HCs, MDDs showed decreased VMHC in visual, motor, somatosensory, limbic, angular gyrus, and cerebellum, particularly in posterior cingulate gyrus/precuneus (PCC/PCu) (false discovery rate [FDR] q < 0.002, z = -7.07). Further analysis observed that the reduction in SMG and insula was more prominent with age, of which SMG reflected such age-related change in males instead of females. Besides, the reduction in MTG was found to be a male-special abnormal pattern in MDDs. VMHC alterations were markedly related to episode type and illness severity. The higher Hamilton Depression Rating Scale score, the more apparent VMHC reduction in the primary visual cortex. First-episode MDDs revealed stronger VMHC reduction in PCu relative to recurrent MDDs. CONCLUSIONS: We confirmed a significant VMHC reduction in MDDs in broad areas, especially in PCC/PCu. This reduction was affected by gender, age, episode type, and illness severity. These findings suggest that the depressive brain tends to disconnect information exchange across hemispheres.


Asunto(s)
Trastorno Bipolar , Trastorno Depresivo Mayor , Adolescente , Adulto , Encéfalo/diagnóstico por imagen , Mapeo Encefálico/métodos , Femenino , Humanos , Imagen por Resonancia Magnética/métodos , Masculino , Persona de Mediana Edad , Adulto Joven
8.
Methods ; 191: 44-58, 2021 07.
Artículo en Inglés | MEDLINE | ID: mdl-33444739

RESUMEN

Mutagenesis studies have rapidly evolved in the era of CRISPR genome editing. Precise manipulation of genes in human induced pluripotent stem cells (iPSCs) allows biomedical researchers to study the physiological functions of individual genes during development. Furthermore, such genetic manipulation applied to patient-specific iPSCs allows disease modeling, drug screening and development of therapeutics. Although various genome-editing methods have been developed to introduce or remove mutations in human iPSCs, comprehensive strategic designs taking account of the potential side effects of CRISPR editing are needed. Here we present several novel and highly efficient strategies to introduce point mutations, insertions and deletions in human iPSCs, including step-by-step experimental protocols. These approaches involve the application of drug selection for effortless clone screening and the generation of a wild type control strain along with the mutant. We also present several examples of application of these strategies in human iPSCs and show that they are highly efficient and could be applied to other cell types.


Asunto(s)
Edición Génica , Sistemas CRISPR-Cas/genética , Repeticiones Palindrómicas Cortas Agrupadas y Regularmente Espaciadas/genética , Humanos , Células Madre Pluripotentes Inducidas , Mutagénesis
9.
BMC Psychiatry ; 22(1): 655, 2022 10 21.
Artículo en Inglés | MEDLINE | ID: mdl-36271351

RESUMEN

BACKGROUND: The association between childhood trauma (CT) and psychotic-like experiences (PLEs) is well-established. Many previous studies have recognized wisdom as a protective factor for mental health, but its role in the relation between CT and PLEs remains unknown. We aimed to investigate the mediating effect of wisdom in the above association among Chinese college students. METHODS: We conducted a nationwide survey covering 9 colleges across China and recruited a total of 5873 students using online questionnaires between September 14 and October 18, 2021. Convenience sampling was adopted. We employed the San Diego Wisdom Scale (SD-WISE), the Childhood Trauma Questionnaire (CTQ-28), and the 15-item Positive Subscale of the Community Assessment of Psychic Experiences (CAPE-15) to measure the wisdom, CT and PLEs, respectively. Descriptive, correlation, and mediation analysis were utilized. RESULTS: The positive correlation between CT and PLEs was well-replicated among college students (Pearson's r = 0.30, p < 0.001). Wisdom was negatively associated with CT (Pearson's r = - 0.46, p < 0.001) and frequency of PLEs (Pearson's r = - 0.25, p < 0.001). Total wisdom scores partially mediated the relationship between cumulative childhood trauma, neglect, abuse and PLEs, separately. The mediated model respectively explained 21.9%, 42.54% and 18.27% of the effect of CT on PLEs. Our model further suggested that childhood trauma could be related to PLEs through decreasing the following wisdom components: decisiveness, emotional regulation and prosocial behavior. CONCLUSION: For the first time, our results suggested that impaired wisdom played a role in the translation from childhood adversity to subclinical psychotic symptoms, implicating wisdom as a possible target for early intervention for psychosis among young individuals. Longitudinal work is warranted to verify the clinical implications.


Asunto(s)
Experiencias Adversas de la Infancia , Trastornos Psicóticos , Niño , Humanos , Estudios Transversales , Trastornos Psicóticos/psicología , Estudiantes/psicología , Encuestas y Cuestionarios , China/epidemiología
10.
Proc Natl Acad Sci U S A ; 116(18): 9078-9083, 2019 04 30.
Artículo en Inglés | MEDLINE | ID: mdl-30979801

RESUMEN

Major depressive disorder (MDD) is common and disabling, but its neuropathophysiology remains unclear. Most studies of functional brain networks in MDD have had limited statistical power and data analysis approaches have varied widely. The REST-meta-MDD Project of resting-state fMRI (R-fMRI) addresses these issues. Twenty-five research groups in China established the REST-meta-MDD Consortium by contributing R-fMRI data from 1,300 patients with MDD and 1,128 normal controls (NCs). Data were preprocessed locally with a standardized protocol before aggregated group analyses. We focused on functional connectivity (FC) within the default mode network (DMN), frequently reported to be increased in MDD. Instead, we found decreased DMN FC when we compared 848 patients with MDD to 794 NCs from 17 sites after data exclusion. We found FC reduction only in recurrent MDD, not in first-episode drug-naïve MDD. Decreased DMN FC was associated with medication usage but not with MDD duration. DMN FC was also positively related to symptom severity but only in recurrent MDD. Exploratory analyses also revealed alterations in FC of visual, sensory-motor, and dorsal attention networks in MDD. We confirmed the key role of DMN in MDD but found reduced rather than increased FC within the DMN. Future studies should test whether decreased DMN FC mediates response to treatment. All R-fMRI indices of data contributed by the REST-meta-MDD consortium are being shared publicly via the R-fMRI Maps Project.


Asunto(s)
Encéfalo/fisiopatología , Trastorno Depresivo Mayor/fisiopatología , Mapeo Encefálico/métodos , China , Conectoma/métodos , Trastorno Depresivo Mayor/diagnóstico por imagen , Trastorno Depresivo Mayor/metabolismo , Femenino , Humanos , Imagen por Resonancia Magnética/métodos , Masculino , Vías Nerviosas/fisiopatología , Descanso/fisiología
11.
Compr Psychiatry ; 111: 152274, 2021 11.
Artículo en Inglés | MEDLINE | ID: mdl-34560369

RESUMEN

BACKGROUND: The COVID-19 pandemic has increased psychological stress among adolescents, and the relation between perceived stress (PS) and psychotic-like experiences (PLEs) has been well-established. However, little is known about the role of family functioning (FF) in this relation, especially when adolescents experienced the extended lockdown period with family members. METHODS: A total of 4807 adolescents completed this retrospective paper-and-pencil survey after school reopening between May 14th and June 6th, 2020 in Hunan Province, China. We measured PS with the Perceived stress scale (PSS-10), PLEs with the eight positive items from Community Assessment of Psychic Experiences (CAPE-8), and FF with the Family APGAR scale. We conducted subgroup analysis based on three FF levels (good, moderate, and poor) determined by previous studies. Finally, correlation and moderation analysis were performed to detect the effect of FF in the relation between PS and PLEs after adjusting for demographic variables. RESULTS: Adolescents with poor FF had higher levels of PS and higher prevalence of PLEs compared to those with good FF (both p < 0.001). FF was negatively associated with both PS (r = -0.34, p < 0.001) and PLEs (r = -0.29, p < 0.001). Higher FF significantly attenuated the effect of PS on PLEs after adjusting for sex and age (effect = -0.011, bootstrap 95% CI -0.018, -0.005). CONCLUSION: Our findings indicate that well-functioned family could protect against stress-induced PLEs among adolescents during this crisis. Thus family system could be an early interventional target for distressing psychotic-like experiences in youngsters.


Asunto(s)
COVID-19 , Trastornos Psicóticos , Adolescente , Control de Enfermedades Transmisibles , Humanos , Pandemias , Trastornos Psicóticos/diagnóstico , Trastornos Psicóticos/epidemiología , Estudios Retrospectivos , SARS-CoV-2 , Estrés Psicológico/epidemiología , Encuestas y Cuestionarios
12.
Aust N Z J Psychiatry ; 55(6): 577-587, 2021 06.
Artículo en Inglés | MEDLINE | ID: mdl-33322919

RESUMEN

BACKGROUND: Working memory deficits are a common feature in major depressive disorder and are associated with poor functional outcomes. Intact working memory performance requires the recruitment of large-scale brain networks. However, it is unknown how the disrupted recruitment of distributed regions belonging to these large-scale networks at the whole-brain level brings about working memory impairment seen in major depressive disorder. METHODS: We used graph theory to examine the functional connectomic metrics (local and global efficiency) at the whole-brain and large-scale network levels in 38 patients with major depressive disorder and 41 healthy controls during a working memory task. Altered connectomic metrics were studied in a moderation model relating to clinical symptoms and working memory accuracy in patients, and a machine learning method was employed to assess whether these metrics carry enough illness-specific information to discriminate patients from controls. RESULTS: Global efficiency of the frontoparietal network was reduced in major depressive disorder (false discovery rate corrected, p = 0.014); this reduction predicted worse working memory performance in patients with less severe illness burden indexed by Brief Psychiatric Rating Scale (ß =-0.43, p = 0.035, t =-2.2, 95% confidence interval = [-0.043,-0.002]). We achieved a classification accuracy and area under the curve of 73.42% and 0.734, respectively, to discriminate patients from controls based on connectomic metrics, and the global efficiency of the frontoparietal network contributed most to the diagnostic classification. CONCLUSIONS: We report a putative mechanistic link between the global efficiency of the frontoparietal network and impaired n-back performance in major depressive disorder. This relationship is more pronounced at lower levels of symptom burden, indicating the possibility of multiple pathways to cognitive deficits in severe major depressive disorder.


Asunto(s)
Conectoma , Trastorno Depresivo Mayor , Encéfalo , Humanos , Imagen por Resonancia Magnética , Trastornos de la Memoria , Memoria a Corto Plazo
13.
Nucleic Acids Res ; 44(17): 8395-406, 2016 09 30.
Artículo en Inglés | MEDLINE | ID: mdl-27484477

RESUMEN

The superfamily of 3'-5' polymerases synthesize RNA in the opposite direction to all other DNA/RNA polymerases, and its members include eukaryotic tRNA(His) guanylyltransferase (Thg1), as well as Thg1-like proteins (TLPs) of unknown function that are broadly distributed, with family members in all three domains of life. Dictyostelium discoideum encodes one Thg1 and three TLPs (DdiTLP2, DdiTLP3 and DdiTLP4). Here, we demonstrate that depletion of each of the genes results in a significant growth defect, and that each protein catalyzes a unique biological reaction, taking advantage of specialized biochemical properties. DdiTLP2 catalyzes a mitochondria-specific tRNA(His) maturation reaction, which is distinct from the tRNA(His) maturation reaction typically catalyzed by Thg1 enzymes on cytosolic tRNA. DdiTLP3 catalyzes tRNA repair during mitochondrial tRNA 5'-editing in vivo and in vitro, establishing template-dependent 3'-5' polymerase activity of TLPs as a bona fide biological activity for the first time since its unexpected discovery more than a decade ago. DdiTLP4 is cytosolic and, surprisingly, catalyzes robust 3'-5' polymerase activity on non-tRNA substrates, strongly implying further roles for TLP 3'-5' polymerases in eukaryotes.


Asunto(s)
ARN Polimerasas Dirigidas por ADN/metabolismo , Dictyostelium/enzimología , Biocatálisis , Dictyostelium/crecimiento & desarrollo , Proteínas Protozoarias/metabolismo , ARN/metabolismo , Edición de ARN/genética , Interferencia de ARN , ARN Mitocondrial , ARN de Transferencia de Histidina/metabolismo , Fracciones Subcelulares/enzimología , Especificidad por Sustrato
14.
J Biol Chem ; 289(22): 15155-65, 2014 May 30.
Artículo en Inglés | MEDLINE | ID: mdl-24737330

RESUMEN

Mitochondrial tRNA (mt-tRNA) 5'-editing was first described more than 20 years ago; however, the first candidates for 5'-editing enzymes were only recently identified in a eukaryotic microbe (protist), the slime mold Dictyostelium discoideum. In this organism, eight of 18 mt-tRNAs are predicted to be edited based on the presence of genomically encoded mismatched nucleotides in their aminoacyl-acceptor stem sequences. Here, we demonstrate that mt-tRNA 5'-editing occurs at all predicted sites in D. discoideum as evidenced by changes in the sequences of isolated mt-tRNAs compared with the expected sequences encoded by the mitochondrial genome. We also identify two previously unpredicted editing events in which G-U base pairs are edited in the absence of any other genomically encoded mismatches. A comparison of 5'-editing in D. discoideum with 5'-editing in another slime mold, Polysphondylium pallidum, suggests organism-specific idiosyncrasies in the treatment of U-G/G-U pairs. In vitro activities of putative D. discoideum editing enzymes are consistent with the observed editing reactions and suggest an overall lack of tRNA substrate specificity exhibited by the repair component of the editing enzyme. Although the presence of terminal mismatches in mt-tRNA sequences is highly predictive of the occurrence of mt-tRNA 5'-editing, the variability in treatment of U-G/G-U base pairs observed here indicates that direct experimental evidence of 5'-editing must be obtained to understand the complete spectrum of mt-tRNA editing events in any species.


Asunto(s)
Dictyostelium/genética , Edición de ARN/genética , ARN de Transferencia/genética , ARN/genética , Disparidad de Par Base , ARN Polimerasas Dirigidas por ADN/metabolismo , Dictyostelium/enzimología , Mitocondrias/genética , Mixomicetos/genética , Conformación de Ácido Nucleico , ARN/química , ARN Mitocondrial , ARN de Transferencia/química
15.
Int J Mol Sci ; 15(12): 23975-98, 2014 Dec 22.
Artículo en Inglés | MEDLINE | ID: mdl-25535083

RESUMEN

During maturation, tRNA molecules undergo a series of individual processing steps, ranging from exo- and endonucleolytic trimming reactions at their 5'- and 3'-ends, specific base modifications and intron removal to the addition of the conserved 3'-terminal CCA sequence. Especially in mitochondria, this plethora of processing steps is completed by various editing events, where base identities at internal positions are changed and/or nucleotides at 5'- and 3'-ends are replaced or incorporated. In this review, we will focus predominantly on the latter reactions, where a growing number of cases indicate that these editing events represent a rather frequent and widespread phenomenon. While the mechanistic basis for 5'- and 3'-end editing differs dramatically, both reactions represent an absolute requirement for generating a functional tRNA. Current in vivo and in vitro model systems support a scenario in which these highly specific maturation reactions might have evolved out of ancient promiscuous RNA polymerization or quality control systems.


Asunto(s)
Edición de ARN , ARN de Transferencia/genética , ARN de Transferencia/metabolismo , Animales , Evolución Biológica , Humanos , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo
16.
Front Psychiatry ; 15: 1456714, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39238939

RESUMEN

Females and males are known to be different in the prevalences of multiple psychiatric disorders, while the underlying neural mechanisms are unclear. Based on non-invasive neuroimaging techniques and graph theory, many researchers have tried to use a small-world network model to elucidate sex differences in the brain. This manuscript aims to compile the related research findings from the past few years and summarize the sex differences in human brain networks in both normal and psychiatric populations from the perspective of small-world properties. We reviewed published reports examining altered small-world properties in both the functional and structural brain networks between males and females. Based on four patterns of altered small-world properties proposed: randomization, regularization, stronger small-worldization, and weaker small-worldization, we found that current results point to a significant trend toward more regularization in normal females and more randomization in normal males in functional brain networks. On the other hand, there seems to be no consensus to date on the sex differences in small-world properties of the structural brain networks in normal populations. Nevertheless, we noticed that the sample sizes in many published studies are small, and future studies with larger samples are warranted to obtain more reliable results. Moreover, the number of related studies conducted in psychiatric populations is still limited and more investigations might be needed. We anticipate that these conclusions will contribute to a deeper understanding of the sex differences in the brain, which may be also valuable for developing new methods in the treatment of psychiatric disorders.

17.
J Affect Disord ; 350: 867-876, 2024 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-38272370

RESUMEN

BACKGROUND: There are rare studies about the network structure of psychotic-like experiences (PLEs) and depressive symptoms among adolescents. Studies have widely acknowledged that PLEs in adolescents confer a higher risk of depressive symptoms, but the complex interactions remain inadequately understood. Our study aimed to examine the hierarchy and inter-associations of PLEs and depressive symptoms in a large adolescent sample from the network analysis perspective. METHODS: A total of 5008 Chinese adolescents were enrolled in our sample. Community Assessment of Psychic Experiences-42 (CAPE-42) was applied to build the network. Centrality indexes were calculated to represent the significance of nodes in the network. Community detection was conducted to figure out the specific clustering of nodes. Demographic information was collected for the sub-network comparisons. Accuracy and stability of the network were also tested. RESULTS: "Failure", "External control", and "Lack of activity" were the most central nodes. The main bridge nodes linking PLEs and depressive symptoms were "Failure", "Guilty", and "No future". Positive PLE "Odd looks" and negative PLE "Unable to terminate" are the two PLEs that were most relevant to depressive nodes. Community detection further demonstrated the bias of depressive nodes in the data-driven clustering. Comparative sub-network analysis suggested that age was the only demographic factor related to the current network. CONCLUSION: In this study of a large adolescent sample, we first demonstrated the network structure and specific clustering preference of PLEs and depressive symptoms. Our findings may enhance the understanding of the relationship between PLE and depressive symptoms.


Asunto(s)
Trastornos Psicóticos , Humanos , Adolescente , Trastornos Psicóticos/epidemiología , Trastornos Psicóticos/diagnóstico , Depresión/epidemiología , Análisis por Conglomerados , Pueblo Asiatico , China/epidemiología , Encuestas y Cuestionarios
18.
Front Psychol ; 15: 1384807, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39246309

RESUMEN

The 33-item Childhood Trauma Questionnaire (CTQ-33) is a recently developed tool expanded from the 28-item Childhood Trauma Questionnaire (CTQ-28) to assess childhood trauma events, which showed good test-retest reliability over 2 weeks. However, little is known regarding the factor structure and long-term test-retest reliability of the CTQ-33. To fill such a gap, this study investigated the factorial validity of the CTQ-33 and test-retest reliability of the scale over a relatively long interval of 1 year. Data on demographics, the CTQ-33 scores, and mental health statuses such as depressive/anxiety symptoms were collected in Chinese adolescents (n = 188) twice across a one-year period. Results of the confirmatory factor analysis (CFA) revealed that the Chinese version of CTQ-33 has close factor validity when compared to the original CTQ-28 in college students. Furthermore, the total and most subscale scores of the CTQ-33 have fair to good test-retest reliability (intra-class correlation coefficients >0.6 for the total score, and > 0.4 for most subscales), except for the physical abuse subscale. Moreover, we replicated previous findings of significant positive relationships between levels of different childhood trauma subtypes using the CTQ-33. These findings provide initial evidence supporting that the CTQ-33 is overall reliable to assess childhood traumatic events in adolescents over relatively long intervals.

19.
JAMA Netw Open ; 7(3): e241933, 2024 Mar 04.
Artículo en Inglés | MEDLINE | ID: mdl-38470418

RESUMEN

Importance: Adolescent major depressive disorder (MDD) is associated with serious adverse implications for brain development and higher rates of self-injury and suicide, raising concerns about its neurobiological mechanisms in clinical neuroscience. However, most previous studies regarding the brain alterations in adolescent MDD focused on single-modal images or analyzed images of different modalities separately, ignoring the potential role of aberrant interactions between brain structure and function in the psychopathology. Objective: To examine alterations of structural and functional connectivity (SC-FC) coupling in adolescent MDD by integrating both diffusion magnetic resonance imaging (MRI) and resting-state functional MRI data. Design, Setting, and Participants: This cross-sectional study recruited participants aged 10 to 18 years from January 2, 2020, to December 28, 2021. Patients with first-episode MDD were recruited from the outpatient psychiatry clinics at The First Affiliated Hospital of Chongqing Medical University. Healthy controls were recruited by local media advertisement from the general population in Chongqing, China. The sample was divided into 5 subgroup pairs according to different environmental stressors and clinical characteristics. Data were analyzed from January 10, 2022, to February 20, 2023. Main Outcomes and Measures: The SC-FC coupling was calculated for each brain region of each participant using whole-brain SC and FC. Primary analyses included the group differences in SC-FC coupling and clinical symptom associations between SC-FC coupling and participants with adolescent MDD and healthy controls. Secondary analyses included differences among 5 types of MDD subgroups: with or without suicide attempt, with or without nonsuicidal self-injury behavior, with or without major life events, with or without childhood trauma, and with or without school bullying. Results: Final analyses examined SC-FC coupling of 168 participants with adolescent MDD (mean [mean absolute deviation (MAD)] age, 16.0 [1.7] years; 124 females [73.8%]) and 101 healthy controls (mean [MAD] age, 15.1 [2.4] years; 61 females [60.4%]). Adolescent MDD showed increased SC-FC coupling in the visual network, default mode network, and insula (Cohen d ranged from 0.365 to 0.581; false discovery rate [FDR]-corrected P < .05). Some subgroup-specific alterations were identified via subgroup analyses, particularly involving parahippocampal coupling decrease in participants with suicide attempt (partial η2 = 0.069; 90% CI, 0.025-0.121; FDR-corrected P = .007) and frontal-limbic coupling increase in participants with major life events (partial η2 ranged from 0.046 to 0.068; FDR-corrected P < .05). Conclusions and Relevance: Results of this cross-sectional study suggest increased SC-FC coupling in adolescent MDD, especially involving hub regions of the default mode network, visual network, and insula. The findings enrich knowledge of the aberrant brain SC-FC coupling in the psychopathology of adolescent MDD, underscoring the vulnerability of frontal-limbic SC-FC coupling to external stressors and the parahippocampal coupling in shaping future-minded behavior.


Asunto(s)
Experiencias Adversas de la Infancia , Trastorno Depresivo Mayor , Femenino , Humanos , Adolescente , Trastorno Depresivo Mayor/diagnóstico por imagen , Estudios Transversales , Depresión , Encéfalo/diagnóstico por imagen
20.
Commun Biol ; 7(1): 960, 2024 Aug 08.
Artículo en Inglés | MEDLINE | ID: mdl-39117859

RESUMEN

Previous studies in small samples have identified inconsistent cortical abnormalities in major depressive disorder (MDD). Despite genetic influences on MDD and the brain, it is unclear how genetic risk for MDD is translated into spatially patterned cortical vulnerability. Here, we initially examined voxel-wise differences in cortical function and structure using the largest multi-modal MRI data from 1660 MDD patients and 1341 controls. Combined with the Allen Human Brain Atlas, we then adopted transcription-neuroimaging spatial correlation and the newly developed ensemble-based gene category enrichment analysis to identify gene categories with expression related to cortical changes in MDD. Results showed that patients had relatively circumscribed impairments in local functional properties and broadly distributed disruptions in global functional connectivity, consistently characterized by hyper-function in associative areas and hypo-function in primary regions. Moreover, the local functional alterations were correlated with genes enriched for biological functions related to MDD in general (e.g., endoplasmic reticulum stress, mitogen-activated protein kinase, histone acetylation, and DNA methylation); and the global functional connectivity changes were associated with not only MDD-general, but also brain-relevant genes (e.g., neuron, synapse, axon, glial cell, and neurotransmitters). Our findings may provide important insights into the transcriptomic signatures of regional cortical vulnerability to MDD.


Asunto(s)
Trastorno Depresivo Mayor , Transcriptoma , Humanos , Trastorno Depresivo Mayor/genética , Trastorno Depresivo Mayor/fisiopatología , Femenino , Masculino , Adulto , Corteza Cerebral/fisiopatología , Corteza Cerebral/diagnóstico por imagen , Corteza Cerebral/metabolismo , Persona de Mediana Edad , Imagen por Resonancia Magnética , Perfilación de la Expresión Génica
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