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1.
Nature ; 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38693260

RESUMO

The human brain develops through a tightly organized cascade of patterning events, induced by transcription factor expression and changes in chromatin accessibility. Although gene expression across the developing brain has been described at single-cell resolution1, similar atlases of chromatin accessibility have been primarily focused on the forebrain2-4. Here we describe chromatin accessibility and paired gene expression across the entire developing human brain during the first trimester (6-13 weeks after conception). We defined 135 clusters and used multiomic measurements to link candidate cis-regulatory elements to gene expression. The number of accessible regions increased both with age and along neuronal differentiation. Using a convolutional neural network, we identified putative functional transcription factor-binding sites in enhancers characterizing neuronal subtypes. We applied this model to cis-regulatory elements linked to ESRRB to elucidate its activation mechanism in the Purkinje cell lineage. Finally, by linking disease-associated single nucleotide polymorphisms to cis-regulatory elements, we validated putative pathogenic mechanisms in several diseases and identified midbrain-derived GABAergic neurons as being the most vulnerable to major depressive disorder-related mutations. Our findings provide a more detailed view of key gene regulatory mechanisms underlying the emergence of brain cell types during the first trimester and a comprehensive reference for future studies related to human neurodevelopment.

2.
J Environ Manage ; 359: 120998, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38677232

RESUMO

Afforestation is beneficial to improving soil carbon pools. However, due to the lack of deep databases, the variations in soil carbon and the combined effects of multiple factors after afforestation have yet to be adequately explored in >1 m deep soils, especially in areas with deep-rooted plants and thick vadose zones. This study examined the multivariate controls of soil organic carbon (SOC) and inorganic carbon (SIC) in 0-18 m deep under farmland, grassland, willow, and poplar in loess deposits. The novelty of this study is that the factors concurrently affecting deep soil carbon were investigated by multiwavelet coherence and structural equation models. On average, the SOC density (53.1 ± 5.0 kg m-2) was only 12% of SIC density (425.4 ± 13.8 kg m-2), with depth-dependent variations under different land use types. In the soil profiles, the variations in SOC were more obvious in the 0-6 m layer, while SIC variations were mainly observed in the 6-12 m layer. Compared with farmland (SOC: 17.0 kg m-2; SIC: 122.9 kg m-2), the plantation of deciduous poplar (SOC: 28.5 kg m-2; SIC: 144.2 kg m-2) increased the SOC and SIC density within the 0-6 m layer (p < 0.05), but grassland and evergreen willow impacted SOC and SIC density insignificantly. The wavelet coherence analysis showed that, at the large scale (>4 m), SOC and SIC intensities were affected by total nitrogen-magnetic susceptibility and magnetic susceptibility-water content, respectively. The structural equation model further identified that SOC density was directly controlled by total nitrogen (path coefficient = 0.64) and indirectly affected by magnetic susceptibility (path coefficient = 0.36). Further, SOC stimulated the SIC deposition by improving water conservation and electrical conductivity. This study provides new insights into afforestation-induced deep carbon cycles, which have crucial implications for forest management and enhancing ecosystem sustainability in arid regions.


Assuntos
Carbono , Solo , Solo/química , Carbono/análise
3.
Chem Commun (Camb) ; 60(23): 3166-3169, 2024 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-38410041

RESUMO

In this study, we investigated Cas13a's efficacy in trans-cleaving RNA G-quadruplexes (rG4s) as an alternative to ssRNA reporters in CRISPR-Cas13a diagnostics. Our findings demonstrate enhanced efficiency due to the structural arrangement of rG4s. Implementing a simplified CRISPR-Cas13a system based on rG4, we identified SARS-CoV-2 infections in 25 patient samples within 1 hour without target pre-amplification.


Assuntos
COVID-19 , Quadruplex G , Humanos , RNA/genética , RNA/química , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas , COVID-19/diagnóstico
4.
Macromol Rapid Commun ; 45(9): e2300689, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38288905

RESUMO

Polyionic liquid hydrogels attract increasing attention due to their unique properties and potential applications. However, research on amino acid-based polyionic liquid hydrogels is still in its infancy stage. Moreover, the effect of amino acid types on the properties of hydrogels is rarely studied to date. In this work, amino acid-based polyionic liquid hydrogels (D/L-PCAA hydrogels) are synthesized by copolymerizing vinyl choline-amino acid ionic liquids and acrylic acids using Al3+ as a crosslinking agent and bacterial cellulose (BC) as a reinforcing agent. The effects of amino acid types on mechanical and antimicrobial properties are systematically investigated. D-arginine-based hydrogel (D-PCArg) shows the highest tensile strength (220.7 KPa), D-phenylalanine-based hydrogel (D-PCPhe) exhibits the highest elongation at break (1346%), and L-aspartic acid-based hydrogel (L-PCAsp) has the highest elastic modulus (206.9 KPa) and toughness (1.74 MJ m-3). D/L-PCAsp hydrogels demonstrate stronger antibacterial capacity against Escherichia coli and Staphylococcus aureus, and D/L-PCPhe hydrogels possess higher antifungal activity against Cryptococcus neoformans. Moreover, the resultant hydrogels exhibit prominent hemocompatibility and low toxicity, as well as excellent self-healing capabilities (86%) and conductivity (2.8 S m-1). These results indicate that D/L-PCAA hydrogel provides a promise for applications in wound dressings.


Assuntos
Aminoácidos , Antibacterianos , Escherichia coli , Hidrogéis , Líquidos Iônicos , Staphylococcus aureus , Hidrogéis/química , Hidrogéis/farmacologia , Hidrogéis/síntese química , Escherichia coli/efeitos dos fármacos , Aminoácidos/química , Aminoácidos/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Antibacterianos/química , Antibacterianos/farmacologia , Antibacterianos/síntese química , Líquidos Iônicos/química , Líquidos Iônicos/farmacologia , Testes de Sensibilidade Microbiana , Antifúngicos/farmacologia , Antifúngicos/química , Antifúngicos/síntese química , Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Anti-Infecciosos/síntese química
5.
Nature ; 2023 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-38057666

RESUMO

Human limbs emerge during the fourth post-conception week as mesenchymal buds, which develop into fully formed limbs over the subsequent months1. This process is orchestrated by numerous temporally and spatially restricted gene expression programmes, making congenital alterations in phenotype common2. Decades of work with model organisms have defined the fundamental mechanisms underlying vertebrate limb development, but an in-depth characterization of this process in humans has yet to be performed. Here we detail human embryonic limb development across space and time using single-cell and spatial transcriptomics. We demonstrate extensive diversification of cells from a few multipotent progenitors to myriad differentiated cell states, including several novel cell populations. We uncover two waves of human muscle development, each characterized by different cell states regulated by separate gene expression programmes, and identify musculin (MSC) as a key transcriptional repressor maintaining muscle stem cell identity. Through assembly of multiple anatomically continuous spatial transcriptomic samples using VisiumStitcher, we map cells across a sagittal section of a whole fetal hindlimb. We reveal a clear anatomical segregation between genes linked to brachydactyly and polysyndactyly, and uncover transcriptionally and spatially distinct populations of the mesenchyme in the autopod. Finally, we perform single-cell RNA sequencing on mouse embryonic limbs to facilitate cross-species developmental comparison, finding substantial homology between the two species.

6.
Am J Cancer Res ; 13(11): 5513-5530, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38058845

RESUMO

Due to its heterogeneous nature, head and neck squamous cell carcinoma (HNSC) had the worst prognosis. Hence, there is an urgent need to develop novel diagnostic and prognostic models for effective disease management. A multi-layer dry-lab and wet-lab methodologies were adopted in the present study to identify novel diagnostic and prognostic biomarkers of HNSC. Initially, the GSE6631 gene microarray HNSC dataset was retrieved from the Gene Expression Omnibus (GEO) database. The R language-based "limma" package was employed to identify differentially expressed genes (DEGs) between HNSC and control samples. The Cytohubba plug-in software was used to identify the top four hub genes based on the degree score method. The Cancer Genome Atlas (TCGA) datasets, Gene Expression Omnibus (GEO) datasets, clinical HNSC tissue samples, HNSC cell line (FaDu), and normal cell line (HOK) were used to validate the expressions of hub genes. Moreover, additional bioinformatics analyses were performed to further evaluate the mechanisms of hub genes in the development of HNSC. In total, 1372 reliable DEGs were screened from the GSE6631 dataset. Out of these DEGs, only based on the four up-regulated hub genes, including UBE2C (Ubiquitin-conjugating enzyme E2C), BUB1B (BUB1 Mitotic Checkpoint Serine/Threonine Kinase B), MCM4 (Minichromosome Maintenance Complex Component 4), and KIF23 (Kinesin family member 23), we developed and validated a diagnostic and prognostic model for HNSC patients. Moreover, some interesting correlations observed between hub gene expression and infiltration level of immune cells may also improve our understanding of HNSC immunotherapy. In conclusion, we developed a novel diagnostic and prognostic model consisting of the UBE2C, BUB1B, MCM4, and KIF23 genes for HNSC patients. However, the efficiency of this model needs to be verified through more experimental studies.

7.
bioRxiv ; 2023 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-37986877

RESUMO

T cells develop from circulating precursors, which enter the thymus and migrate throughout specialised sub-compartments to support maturation and selection. This process starts already in early fetal development and is highly active until the involution of the thymus in adolescence. To map the micro-anatomical underpinnings of this process in pre- vs. post-natal states, we undertook a spatially resolved analysis and established a new quantitative morphological framework for the thymus, the Cortico-Medullary Axis. Using this axis in conjunction with the curation of a multimodal single-cell, spatial transcriptomics and high-resolution multiplex imaging atlas, we show that canonical thymocyte trajectories and thymic epithelial cells are highly organised and fully established by post-conception week 12, pinpoint TEC progenitor states, find that TEC subsets and peripheral tissue genes are associated with Hassall's Corpuscles and uncover divergence in the pace and drivers of medullary entry between CD4 vs. CD8 T cell lineages. These findings are complemented with a holistic toolkit for spatial analysis and annotation, providing a basis for a detailed understanding of T lymphocyte development.

8.
Science ; 382(6667): eadf1226, 2023 10 13.
Artigo em Inglês | MEDLINE | ID: mdl-37824650

RESUMO

The adult human brain comprises more than a thousand distinct neuronal and glial cell types, a diversity that emerges during early brain development. To reveal the precise sequence of events during early brain development, we used single-cell RNA sequencing and spatial transcriptomics and uncovered cell states and trajectories in human brains at 5 to 14 postconceptional weeks (pcw). We identified 12 major classes that are organized as ~600 distinct cell states, which map to precise spatial anatomical domains at 5 pcw. We described detailed differentiation trajectories of the human forebrain and midbrain and found a large number of region-specific glioblasts that mature into distinct pre-astrocytes and pre-oligodendrocyte precursor cells. Our findings reveal the establishment of cell types during the first trimester of human brain development.


Assuntos
Encéfalo , Neurogênese , Primeiro Trimestre da Gravidez , Feminino , Humanos , Gravidez , Astrócitos/citologia , Encéfalo/citologia , Encéfalo/embriologia , Neuroglia , Neurônios/citologia , Atlas como Assunto , Análise da Expressão Gênica de Célula Única
9.
Heliyon ; 9(7): e18290, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37539185

RESUMO

Background: Laryngeal squamous cell carcinoma (LSCC) belongs to tumors of head and neck. Circular RNA circSLC7A11 functions as oncogenes in various tumors. However, the role of circSLC7A11 in LSCC remains largely unknown. Here, we aimed to clarify the circSLC7A11 function in LSCC. Methods: Relevance between circSLC7A11 expressions and LSCC clinicopathological was checked using chi-square. Relevance between circSLC7A11 expressions and LSCC patients' survival time was validated using Kaplan-Meier analysis. CircSLC7A11 expressions in LSCC tissues and cells were determined using quantitative real-time PCR. CircSLC7A11 functions in LSCC were examined by Cell Counting Kit-8, EdU analysis, Western blot, flow cytometry, sphere formation assay, and Transwell analysis. Meanwhile, circSLC7A11 mechanism in LSCC was determined using dual-luciferase reporter analysis, RNA pull-down, RNA Immunoprecipitation. Results: CircSLC7A11 was highly expressed in LSCC, and high circSLC7A11 expressions were interrelated to the TNM stage. Also, LSCC patients with high circSLC7A11 owned shorter overall survival. Functional studies revealed that circSLC7A11 knockdown reduced LSCC cell proliferation, migration, invasion, stemness characteristics, and enhanced cell apoptosis. Mechanistic study data corroborated that circSLC7A11 targeted miR-877-5p, miR-877-5p targeted LASP1. LASP1 was negatively interrelated to miR-877-5p and was positively interrelated to circSLC7A11 in LSCC tissues. Also, circSLC7A11 knockdown reduced the LASP1 levels, and miR-877-5p inhibitor co-transfection reversed this reduction. Rescue assays further demonstrated that circSLC7A11 accelerated LSCC through miR-877-5p/LASP1. Conclusion: CircSLC7A11 exerted oncogenic functions in LSCC by miR-877-5p/LASP1, hinting that circSLC7A11 was a novel biomarker for LSCC.

10.
Front Plant Sci ; 14: 1206246, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37469781

RESUMO

This study is aimed at investigating the effects of exogenous selenium (Se) on the ionic equilibrium and micro-domain distribution, state transitions between photosystem I (PSI) and photosystem II (PSII), and the photosynthetic carbon assimilation efficiency of tomato (Solanum lycopersicon L.) seedlings under the influence of salt stress. The application of 0.01 mmol•L-1 exogenous Se had no significant effects on the selective transport capacity of sodium (Na), potassium (K), calcium (Ca) and magnesium (Mg) from the roots to leaves under salt stress. It, however, significantly hindered the absorption of Na by the root system and leaves, increased the ratios of K/Na, Ca/Na and Mg/Na, and relieved the nonuniformity of micro-domain ionic distribution, thus, mitigating the ionic homeostasis imbalance and ion toxicity induced by salt stress. Additionally, the application of exogenous Se overcame stomatal limitation, regulated the state transitions between PSI and PSII, and enhanced the initial and overall activity of Rubisco as well as the activities of Rubisco activase (RCA) and fructose-1,6-bisphosphatase (FBPase). It also increased the levels of expression of nine relevant genes in Calvin cycle, which subsequently improved the concentration of photosynthetic substrates, balanced the distribution of activation energy between PSI and PSII, promoted the efficiency of CO2 carboxylation and carbon assimilation, thereby increasing the photosynthetic efficiency of tomato seedling leaves under salt stress. Hence, the supply of exogenous Se can alleviate the inhibition of salt stress on tomato seedling growth by rebuilding ionic homeostasis and promoting photosynthetic capacity.

11.
J Agric Food Chem ; 71(16): 6326-6337, 2023 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-37040528

RESUMO

Human milk phospholipids are important for the regular growth and development of infants. Ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC/Q-TOF-MS) was employed to qualitatively and quantitatively analyze 277 phospholipid molecular species in 112 human milk samples to obtain a detailed profile of human milk phospholipids along the lactation stage. MS/MS fragmentation patterns of sphingomyelin, phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol, and phosphatidylserine were characterized in detail. Phosphatidylcholine is the most dominant group, followed by sphingomyelin. PC(18:0/18:2), SM(d18:1/24:1), PE(18:0/18:0), PS(18:0/20:4), and PI(18:0/18:2) showed the highest average concentration among all of the phosphatidylcholine, sphingomyelin, phosphatidylethanolamine, phosphatidylserine, and phosphatidylinositol molecular species, respectively. The fatty acids attached to the phospholipid molecules were mainly palmitic, stearic, oleic, and linoleic acids, and the plasmalogens decreased along the lactation stage. The increase of sphingomyelins and phosphatidylethanolamines and the decrease of phosphatidylcholines are the key changes from colostrum to transitional milk; the increase of lysophosphatidylcholines and lysophosphatidylethanolamines and the continuous decrease of phosphatidylcholines are the vital changes from transitional milk to mature milk.


Assuntos
Leite Humano , Fosfolipídeos , Feminino , Humanos , Lactação , Lecitinas , Leite Humano/química , Fosfatidilcolinas/análise , Fosfatidiletanolaminas , Fosfatidilinositóis/análise , Fosfatidilserinas , Fosfolipídeos/análise , Esfingomielinas , Espectrometria de Massas em Tandem , Cromatografia Líquida de Alta Pressão
12.
Light Sci Appl ; 12(1): 23, 2023 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-36635271

RESUMO

"New" electro-optical (EO) crystals are hard to find, "old" EO crystals are scarce and each has its own problems, and the demand for high-performance EO crystals by higher power, higher repetition rate, and narrower pulse width laser is realistic and urgent. The EO performance of KTP was recognized as soon as it was discovered, but after more than 40 years of development, the reports, and products of EO devices based on KTP are less than those of other EO crystals, even though KTP is now almost the cheapest nonlinear optical crystal material. In this paper, based on our understanding of the crystal structure of predecessors and ourselves, especially the understanding and practice of quasi-one-dimensional ionic conduction mechanism, we think that crystal growth is the most important reason that affects the controllability of crystal performance. Through a series of science and technology, we realize the growth of large-size crystals with high-optical uniformity, then reduce the absorption of KTP to a very low level, and grow crystals with resistance to electric damage and laser damage. On this basis, reducing the conductivity and improving the uniformity of optical, electrical, piezoelectric, and ferroelectric properties are emphasized. The extinction ratio, piezoelectric ringing effect, and thermal influence of the EO switch based on KTP crystal are tested, and some publicly available progress of using KTP EO devices in high-repetition rate laser is listed. Finally, we are looking forward to the development of KTP EO crystal for the laser system to EO generator for integrated optics.

14.
Sci Rep ; 12(1): 22100, 2022 12 21.
Artigo em Inglês | MEDLINE | ID: mdl-36543795

RESUMO

This study aimed to investigate the risk factors of patients with postpartum hemorrhage (PPH) after cesarean delivery (CD) and to develop a risk-factor model for PPH after CD. Patients were selected from seven affiliated medical institutions of Chongqing Medical University from January 1st, 2015, to January 1st, 2020. Continuous and categorical variables were obtained from the hospital's electronic medical record systems. Independent risk factors were identified by univariate analysis, least absolute shrinkage and selection operator and logistic regression. Furthermore, logistic, extreme gradient boosting, random forest, classification and regression trees, as well as an artificial neural network, were used to build the risk-factor model. A total of 701 PPH cases after CD and 2797 cases of CD without PPH met the inclusion criteria. Univariate analysis screened 28 differential indices. Multi-variable analysis screened 10 risk factors, including placenta previa, gestational age, prothrombin time, thrombin time, fibrinogen, anemia before delivery, placenta accreta, uterine atony, placental abruption and pregnancy with uterine fibroids. Areas under the curve by random forest for the training and test sets were 0.957 and 0.893, respectively. The F1 scores in the random forest training and test sets were 0.708. In conclusion, the risk factors for PPH after CD were identified, and a relatively stable risk-factor model was built.


Assuntos
Descolamento Prematuro da Placenta , Hemorragia Pós-Parto , Humanos , Gravidez , Feminino , Hemorragia Pós-Parto/epidemiologia , Hemorragia Pós-Parto/etiologia , Estudos Retrospectivos , Placenta , Cesárea/efeitos adversos , Fatores de Risco
15.
Cell ; 185(25): 4841-4860.e25, 2022 Dec 08.
Artigo em Inglês | MEDLINE | ID: mdl-36493756

RESUMO

We present a multiomic cell atlas of human lung development that combines single-cell RNA and ATAC sequencing, high-throughput spatial transcriptomics, and single-cell imaging. Coupling single-cell methods with spatial analysis has allowed a comprehensive cellular survey of the epithelial, mesenchymal, endothelial, and erythrocyte/leukocyte compartments from 5-22 post-conception weeks. We identify previously uncharacterized cell states in all compartments. These include developmental-specific secretory progenitors and a subtype of neuroendocrine cell related to human small cell lung cancer. Our datasets are available through our web interface (https://lungcellatlas.org). To illustrate its general utility, we use our cell atlas to generate predictions about cell-cell signaling and transcription factor hierarchies which we rigorously test using organoid models.


Assuntos
Feto , Pulmão , Humanos , Diferenciação Celular , Perfilação da Expressão Gênica , Pulmão/citologia , Organogênese , Organoides , Atlas como Assunto , Feto/citologia
16.
Front Nutr ; 9: 1007184, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36505248

RESUMO

Background: Muscle mass loss is common in long-standing rheumatoid arthritis (RA). The aim was to explore the prevalence and effects of RA disease characteristics in patients with early RA. Methods: This cross-sectional study was carried out based on a Chinese RA cohort and control subjects. The body composition (BC) was assessed using bioelectric impedance analysis. Myopenia was defined by an appendicular skeletal muscle mass index of ≤ 7.0 kg/m2 in men and ≤ 5.7 kg/m2 in women. Physical dysfunction was defined as a health assessment questionnaire disability index > 1. Propensity score matching was performed to balance age and gender differences among patients with early RA (disease duration ≤ 12 months) and established RA, and controls (with 1:3:3 matching). Results: In total, 2017 controls and 1,008 patients with RA were recruited for this study. Among the patients with RA, there were 190 (18.8%) patients with early RA, with a median disease duration of 7 (4, 11) months. The matched patients with early RA (n = 160) showed a higher prevalence of myopenia than the matched controls (41.3 vs. 15.8%, P < 0.0167), but no difference was found in the matched patients with established RA (41.3 vs. 50.4%, P > 0.0167). Compared with the patients with established RA, the patients with early RA exhibited higher disease activity scores [disease activity score in 28 joints with four variables including C-reactive protein (DAS28-CRP): median 4.76 vs. 3.93, P < 0.001] and a higher prevalence of physical dysfunction (26.3 vs. 19.4%, P = 0.035). In the patients with early RA, patients with myopenia showed a higher prevalence of physical dysfunction than those without myopenia (41.3 vs. 15.5%, P < 0.001), among which walking and common daily activities were the most involved subdimensions. Multivariate logistic regression analysis showed that DAS28-CRP was positively associated with myopenia [adjusted odds ratio (AOR) 1.558, 95% CI (1.138-2.132)], and myopenia [AOR 2.983, 95% CI (1.192-7.465)] was independently associated with physical dysfunction in the patients with early RA. Conclusion: Our data indicate the importance of early detection of muscle involvement in the early stage of RA and imply the significance of early aggressive control of disease activity for the prevention of myopenia and physical dysfunction in patients with early RA. Our study provides a new perspective on RA management.

17.
Int J Mol Sci ; 23(21)2022 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-36361956

RESUMO

In vitro models of corticogenesis from pluripotent stem cells (PSCs) have greatly improved our understanding of human brain development and disease. Among these, 3D cortical organoid systems are able to recapitulate some aspects of in vivo cytoarchitecture of the developing cortex. Here, we tested three cortical organoid protocols for brain regional identity, cell type specificity and neuronal maturation. Overall, all protocols gave rise to organoids that displayed a time-dependent expression of neuronal maturation genes such as those involved in the establishment of synapses and neuronal function. Comparatively, guided differentiation methods without WNT activation generated the highest degree of cortical regional identity, whereas default conditions produced the broadest range of cell types such as neurons, astrocytes and hematopoietic-lineage-derived microglia cells. These results suggest that cortical organoid models produce diverse outcomes of brain regional identity and cell type specificity and emphasize the importance of selecting the correct model for the right application.


Assuntos
Organoides , Células-Tronco Pluripotentes , Humanos , Células-Tronco Pluripotentes/metabolismo , Diferenciação Celular , Neurônios/metabolismo , Encéfalo
18.
Development ; 149(23)2022 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-36305490

RESUMO

Significant efforts are ongoing to develop refined differentiation protocols to generate midbrain dopamine (DA) neurons from pluripotent stem cells for application in disease modeling, diagnostics, drug screening and cell-based therapies for Parkinson's disease. An increased understanding of the timing and molecular mechanisms that promote the generation of distinct subtypes of human midbrain DA during development will be essential for guiding future efforts to generate molecularly defined and subtype-specific DA neurons from pluripotent stem cells. Here, we use droplet-based single-cell RNA sequencing to transcriptionally profile the developing human ventral midbrain (VM) when the DA neurons are generated (6-11 weeks post-conception) and their subsequent differentiation into functional mature DA neurons in primary fetal 3D organoid-like cultures. This approach reveals that 3D cultures are superior to monolayer conditions for their ability to generate and maintain mature DA neurons; hence, they have the potential to be used for studying human VM development. These results provide a unique transcriptional profile of the developing human fetal VM and functionally mature human DA neurons that can be used to guide stem cell-based therapies and disease modeling approaches in Parkinson's disease.


Assuntos
Doença de Parkinson , Células-Tronco Pluripotentes , Humanos , Doença de Parkinson/genética , Doença de Parkinson/terapia , Neurônios Dopaminérgicos , Mesencéfalo , Diferenciação Celular/genética
19.
Int J Mol Sci ; 23(17)2022 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-36077120

RESUMO

How to fabricate bone tissue engineering scaffolds with excellent antibacterial and bone regeneration ability has attracted increasing attention. Herein, we produced a hierarchical porous ß-tricalcium phosphate (ß-TCP)/poly(lactic-co-glycolic acid)-polycaprolactone composite bone tissue engineering scaffold containing tetracycline hydrochloride (TCH) through a micro-extrusion-based cryogenic 3D printing of Pickering emulsion inks, in which the hydrophobic silica (h-SiO2) nanoparticles were used as emulsifiers to stabilize composite Pickering emulsion inks. Hierarchically porous scaffolds with desirable antibacterial properties and bone-forming ability were obtained. Grid scaffolds with a macroscopic pore size of 250.03 ± 75.88 µm and a large number of secondary micropores with a diameter of 24.70 ± 15.56 µm can be fabricated through cryogenic 3D printing, followed by freeze-drying treatment, whereas the grid structure of scaffolds printed or dried at room temperature was discontinuous, and fewer micropores could be observed on the strut surface. Moreover, the impartment of ß-TCP in scaffolds changed the shape and density of the micropores but endowed the scaffold with better osteoconductivity. Scaffolds loaded with TCH had excellent antibacterial properties and could effectively promote the adhesion, expansion, proliferation, and osteogenic differentiation of rat bone marrow-derived mesenchymal stem cells afterward. The scaffolds loaded with TCH could realize the strategy to "kill bacteria first, then induce osteogenesis". Such hierarchically porous scaffolds with abundant micropores, excellent antibacterial property, and improved bone-forming ability display great prospects in treating bone defects with infection.


Assuntos
Osteogênese , Engenharia Tecidual , Animais , Antibacterianos/farmacologia , Regeneração Óssea , Emulsões/farmacologia , Porosidade , Impressão Tridimensional , Ratos , Dióxido de Silício/farmacologia , Alicerces Teciduais/química
20.
J Mech Behav Biomed Mater ; 135: 105487, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-36179614

RESUMO

Three bi-quaternary ammonium methacrylates (biQAMA-12, biQAMA-14, and biQAMA-16) with different alkyl chain length were synthesized with the purpose of endowing dental resin composites (DRCs) with antibacterial activity without sacrificing physicochemical properties of DRCs. All of biQAMAs were confirmed by 1H-NMR spectra and incorporated into Bis-GMA/TEGDMA (60 wt/40 wt) resin matrix with a mass fraction of 5 wt% as antibacterial agent. The obtained resin matrixes were mixed with commercial silaned glass fillers at a mass ratio of 30 wt/70 wt to prepare antibacterial DRCs. The double bond conversion (DC), antibacterial activity against S. mutans., surface charge density, water contact angle, water sorption (WS) and solubility (SL), mechanical properties, and cytotoxicity of biQAMAs containing DRCs were investigated. The DRC without biQAMAs was used as control. The results showed that all biQAMAs containing DRCs had antibacterial rate higher than 90%, and DRC with biQAMA-12 had the highest antibacterial rate due to its highest surface charge density. Adding 5 wt% of biQAMAs would not bring out negative effect on physicochemical properties of DRCs, except for increasing WS, but the resultant WS still met the ISO requirement on WS of restorative materials. Both biQAMA-14 and biQAMA-16 containing DRCs showed higher cytotoxicity than control, thus biQAMA-12 was considered as the optimal antibacterial agent in this research.


Assuntos
Compostos de Amônio , Metacrilatos , Antibacterianos/química , Antibacterianos/farmacologia , Anticestoides , Bis-Fenol A-Glicidil Metacrilato/química , Resinas Compostas/farmacologia , Teste de Materiais , Metacrilatos/química , Metacrilatos/farmacologia , Água/química
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