Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 27
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
BMC Genomics ; 25(1): 444, 2024 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-38711017

RESUMO

BACKGROUND: Normalization is a critical step in the analysis of single-cell RNA-sequencing (scRNA-seq) datasets. Its main goal is to make gene counts comparable within and between cells. To do so, normalization methods must account for technical and biological variability. Numerous normalization methods have been developed addressing different sources of dispersion and making specific assumptions about the count data. MAIN BODY: The selection of a normalization method has a direct impact on downstream analysis, for example differential gene expression and cluster identification. Thus, the objective of this review is to guide the reader in making an informed decision on the most appropriate normalization method to use. To this aim, we first give an overview of the different single cell sequencing platforms and methods commonly used including isolation and library preparation protocols. Next, we discuss the inherent sources of variability of scRNA-seq datasets. We describe the categories of normalization methods and include examples of each. We also delineate imputation and batch-effect correction methods. Furthermore, we describe data-driven metrics commonly used to evaluate the performance of normalization methods. We also discuss common scRNA-seq methods and toolkits used for integrated data analysis. CONCLUSIONS: According to the correction performed, normalization methods can be broadly classified as within and between-sample algorithms. Moreover, with respect to the mathematical model used, normalization methods can further be classified into: global scaling methods, generalized linear models, mixed methods, and machine learning-based methods. Each of these methods depict pros and cons and make different statistical assumptions. However, there is no better performing normalization method. Instead, metrics such as silhouette width, K-nearest neighbor batch-effect test, or Highly Variable Genes are recommended to assess the performance of normalization methods.


Assuntos
Análise de Célula Única , Análise de Célula Única/métodos , Humanos , Perfilação da Expressão Gênica/métodos , Perfilação da Expressão Gênica/normas , Análise de Sequência de RNA/métodos , Transcriptoma , Algoritmos , RNA-Seq/métodos , RNA-Seq/normas , Animais
2.
Clin Interv Aging ; 19: 613-626, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38646591

RESUMO

Purpose: This study aims to investigate how the type of anesthesia used during major orthopedic surgery may impact adverse short-term postoperative outcomes depending on frailty. Methods: To conduct this investigation, we recruited individuals aged 65 years and older who underwent major orthopedic surgery between March 2022 and April 2023 at a single institution. We utilized the FRAIL scale to evaluate frailty. The primary focus was on occurrences of death or the inability to walk 60 days after the surgery. Secondary measures included death within 60 days; inability to walk without human assistance at 60 days; death or the inability to walk without human assistance at 30 days after surgery, the first time out of bed after surgery, postoperative blood transfusion, length of hospital stay, hospital costs, and the occurrence of surgical complications such as dislocation, periprosthetic fracture, infection, reoperation, wound complications/hematoma. Results: In a study of 387 old adult patients who had undergone major orthopedic surgery, 41.3% were found to be in a frail state. Among these patients, 262 had general anesthesia and 125 had neuraxial anesthesia. Multifactorial logistic regression analyses showed that anesthesia type was not linked to complications. Instead, frailty (OR 4.04, 95% CI 1.04 to 8.57, P< 0.001), age (OR 1.05, 95% CI 1.00-1.10, P= 0.017), and aCCI scores, age-adjusted Charlson Comorbidity Index, (OR 1.36, 95% CI 1.12 to 1.66, P= 0.002) were identified as independent risk factors for death or new walking disorders in these patients 60 days after surgery. After adjusting for frailty, anesthesia methods was not associated with the development of death or new walking disorders in these patients (P > 0.05). Conclusion: In different frail populations, neuraxial anesthesia is likely to be comparable to general anesthesia in terms of the incidence of short-term postoperative adverse outcomes.


Assuntos
Fragilidade , Tempo de Internação , Procedimentos Ortopédicos , Complicações Pós-Operatórias , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Anestesia Geral/efeitos adversos , Idoso Fragilizado , Tempo de Internação/estatística & dados numéricos , Modelos Logísticos , Procedimentos Ortopédicos/efeitos adversos , Complicações Pós-Operatórias/epidemiologia , Estudos Prospectivos , Fatores de Risco
3.
Aging Dis ; 2024 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-38502590

RESUMO

Alzheimer's disease (AD) is characterized by the presence of two hallmark pathologies: the accumulation of Amyloid beta (Aß) and tau proteins in the brain. There is a growing body of evidence suggesting that astrocytes, a type of glial cell in the brain, play crucial roles in clearing Aß and binding to tau proteins. However, due to the heterogeneity of astrocytes, the specific roles of different astrocyte subpopulations in response to Aß and tau remain unclear. To enhance the understanding of astrocyte subpopulations in AD, we investigated astrocyte lineage cells based on single-nuclei transcriptomic data obtained from both human and mouse samples. We characterized the diversity of astrocytes and identified global and subpopulation-specific transcriptomic changes between control and AD samples. Our findings revealed the existence of a specific astrocyte subpopulation marked by low levels of GFAP and the presence of AQP4 and CD63 expression, which showed functional enrichment in Aß clearance and tau protein binding, and diminished in AD. We verified this type of astrocytes in mouse models and in AD patient brain samples. Furthermore, our research also unveiled significant alterations of the ligand-receptor interactions between astrocytes and other cell types. These changes underscore the complex interplay between astrocytes and neighboring cells in the context of AD. Overall, our work gives insights into astrocyte heterogeneity in the context of AD and reveals a distinct astrocyte subpopulation that holds potential for therapeutic interventions in AD. Targeting specific astrocyte subpopulations may offer new avenues for the development of novel treatments for AD.

4.
Cell Mol Life Sci ; 80(12): 362, 2023 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-37979052

RESUMO

A hallmark of inherited retinal degenerative diseases such as retinitis pigmentosa (RP) is progressive structural and functional remodeling of the remaining retinal cells as photoreceptors degenerate. Extensive remodeling of the retina stands as a barrier for the successful implementation of strategies to restore vision. To understand the molecular basis of remodeling, we performed analyses of single-cell transcriptome data from adult zebrafish retina of wild type AB strain (WT) and a P23H mutant rhodopsin transgenic model of RP with continuous degeneration and regeneration. Retinas from both female and male fish were pooled to generate each library, combining data from both sexes. We provide a benchmark atlas of retinal cell type transcriptomes in zebrafish and insight into how each retinal cell type is affected in the P23H model. Oxidative stress is found throughout the retina, with increases in reliance on oxidative metabolism and glycolysis in the affected rods as well as cones, bipolar cells, and retinal ganglion cells. There is also transcriptional evidence for widespread synaptic remodeling and enhancement of glutamatergic transmission in the inner retina. Notably, changes in circadian rhythm regulation are detected in cones, bipolar cells, and retinal pigmented epithelium. We also identify the transcriptomic signatures of retinal progenitor cells and newly formed rods essential for the regenerative process. This comprehensive transcriptomic analysis provides a molecular road map to understand how the retina remodels in the context of chronic retinal degeneration with ongoing regeneration.


Assuntos
Degeneração Retiniana , Retinose Pigmentar , Animais , Masculino , Feminino , Peixe-Zebra/genética , Retina/metabolismo , Retinose Pigmentar/genética , Retinose Pigmentar/metabolismo , Células Fotorreceptoras Retinianas Bastonetes/metabolismo , Degeneração Retiniana/metabolismo , Modelos Animais de Doenças
5.
Inorg Chem ; 62(32): 12793-12802, 2023 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-37531406

RESUMO

Plant growth can be controlled and freed from natural environmental interference through indoor plant cultivation. Artificial light sources with better quality are required to promote indoor plant growth. In this study, we used a simple high-temperature solid-state reaction to synthesize high-efficiency Ce3+-activated NaGdSiO4 (NGSO) phosphors. X-ray diffraction and Rietveld refinement were performed to determine the detailed crystal structure of the NGSO:Ce3+ phosphors. The morphology of NGSO:Ce3+ and the elemental state of Ce3+ were measured and analyzed. Under near-ultraviolet (n-UV) light excitation, the Ce3+-activated NGSO phosphors exhibit a broad emission band from 375 to 500 nm, and their emission peaks are at approximately 401 nm. This asymmetrical blue emission band is caused by the spin-allowed 5d → 4f transition of Ce3+ and overlaps well with the blue absorption region of carotenoids and chlorophyll. The temperature-dependent luminescence spectra were utilized to assess the thermal stability of NGSO:Ce3+. The external quantum efficiency (EQE) was measured to be 60.91%, and the internal quantum efficiency (IQE) was measured to be 73.39%. A blue LED device assembled from the NGSO:Ce3+ phosphor has demonstrated the application potential in accelerating plant growth.

6.
Cell Rep ; 42(5): 112486, 2023 05 30.
Artigo em Inglês | MEDLINE | ID: mdl-37149868

RESUMO

Recent studies have revealed the heterogeneous nature of astrocytes; however, how diverse constituents of astrocyte-lineage cells are regulated in adult spinal cord after injury and contribute to regeneration remains elusive. We perform single-cell RNA sequencing of GFAP-expressing cells from sub-chronic spinal cord injury models and identify and compare with the subpopulations in acute-stage data. We find subpopulations with distinct functional enrichment and their identities defined by subpopulation-specific transcription factors and regulons. Immunohistochemistry, RNAscope experiments, and quantification by stereology verify the molecular signature, location, and morphology of potential resident neural progenitors or neural stem cells in the adult spinal cord before and after injury and uncover the populations of the intermediate cells enriched in neuronal genes that could potentially transition into other subpopulations. This study has expanded the knowledge of the heterogeneity and cell state transition of glial progenitors in adult spinal cord before and after injury.


Assuntos
Neuroglia , Traumatismos da Medula Espinal , Humanos , Traumatismos da Medula Espinal/genética , Astrócitos , Neurônios , Medula Espinal , Análise de Sequência de RNA
7.
Cell Rep ; 42(3): 112239, 2023 03 28.
Artigo em Inglês | MEDLINE | ID: mdl-36906851

RESUMO

It is widely believed that hematopoiesis after birth is established by hematopoietic stem cells (HSCs) in the bone marrow and that HSC-independent hematopoiesis is limited only to primitive erythro-myeloid cells and tissue-resident innate immune cells arising in the embryo. Here, surprisingly, we find that significant percentages of lymphocytes are not derived from HSCs, even in 1-year-old mice. Instead, multiple waves of hematopoiesis occur from embryonic day 7.5 (E7.5) to E11.5 endothelial cells, which simultaneously produce HSCs and lymphoid progenitors that constitute many layers of adaptive T and B lymphocytes in adult mice. Additionally, HSC lineage tracing reveals that the contribution of fetal liver HSCs to peritoneal B-1a cells is minimal and that the majority of B-1a cells are HSC independent. Our discovery of extensive HSC-independent lymphocytes in adult mice attests to the complex blood developmental dynamics spanning the embryo-to-adult transition and challenges the paradigm of HSCs exclusively underpinning the postnatal immune system.


Assuntos
Células Endoteliais , Células-Tronco Hematopoéticas , Animais , Camundongos , Linhagem da Célula , Medula Óssea , Hematopoese
8.
Parasit Vectors ; 15(1): 205, 2022 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-35698238

RESUMO

BACKGROUND: Plasmodium vivax reticulocyte binding protein 2b (PvRBP2b) plays a critical role in parasite invasion of reticulocytes by binding the transferrin receptor 1. PvRBP2b is a vaccine candidate based on the negative correlation between antibody titers against PvRBP2b recombinant proteins and parasitemia and risk of vivax malaria. The aim of this study was to analyze the genetic diversity of the PvRBP2b gene in the global P. vivax populations. METHODS: Near full-length PvRBP2b nucleotide sequences (190-8349 bp) were obtained from 88 P. vivax isolates collected from the China-Myanmar border (n = 44) and Thailand (n = 44). An additional 224 PvRBP2b sequences were retrieved from genome sequences from parasite populations worldwide. The genetic diversity, neutral selection, haplotype distribution and genetic differentiation of PvRBP2b were examined. RESULTS: The genetic diversity of PvRBP2b was distributed unevenly, with peak diversity found in the reticulocyte binding region in the N-terminus. Neutrality analysis suggested that this region is subjected to balancing selection or population bottlenecks. Several amino acid variants were found in all or nearly all P. vivax endemic regions. However, the critical residues responsible for reticulocyte binding were highly conserved. There was substantial population differentiation according to the geographical separation. The distribution of haplotypes in the reticulocyte binding region varied among regions; even the two major haplotypes Hap_6 and Hap_8 were found in only five populations. CONCLUSIONS: Our data show considerable genetic variations of PvRBPb in global parasite populations. The geographic divergence may pose a challenge to PvRBP2b-based vaccine development.


Assuntos
Malária Vivax , Parasitos , Animais , Antígenos de Protozoários/genética , Antígenos de Protozoários/metabolismo , Variação Genética , Haplótipos , Malária Vivax/parasitologia , Plasmodium vivax/genética , Proteínas de Protozoários/metabolismo , Reticulócitos , Seleção Genética
9.
Cell Mol Life Sci ; 79(2): 123, 2022 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-35129669

RESUMO

Traumatic brain injury (TBI) and spinal cord injury (SCI) are two main central nervous system (CNS) traumas, caused by external physical insults. Both injuries have devastating effects on the quality of life, and there is no effective therapy at present. Notably, gene expression profiling using bulk RNA sequencing (RNA-Seq) and single-cell RNA-Seq (scRNA-Seq) have revealed significant changes in many coding and non-coding genes, as well as important pathways in SCI and TBI. Particularly, recent studies have revealed that long non-coding RNAs (lncRNAs) with lengths greater than 200 nucleotides and without protein-coding potential have tissue- and cell type-specific expression pattern and play critical roles in CNS injury by gain- and loss-of-function approaches. LncRNAs have been shown to regulate protein-coding genes or microRNAs (miRNAs) directly or indirectly, participating in processes including inflammation, glial activation, cell apoptosis, and vasculature events. Therefore, lncRNAs could serve as potential targets for the diagnosis, treatment, and prognosis of SCI and TBI. In this review, we highlight the recent progress in transcriptome studies of SCI and TBI and insights into molecular mechanisms.


Assuntos
Lesões Encefálicas Traumáticas/metabolismo , RNA Longo não Codificante/metabolismo , Traumatismos da Medula Espinal/metabolismo , Animais , Regulação da Expressão Gênica , Humanos , Transcriptoma
10.
Front Neurol ; 12: 619626, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34531807

RESUMO

Alzheimer's disease (AD) is a progressive neurodegenerative disease and is the most common cause of dementia in an aging population. The majority of research effort has focused on the role of neurons in neurodegeneration and current therapies have limited ability to slow disease progression. Recently more attention has been given to the role of astrocytes in the process of neurodegeneration. Specifically, reactive astrocytes have both advantageous and adverse effects during neurodegeneration. The ability to isolate and depict astrocyte phenotype has been challenging. However, with the recent development of single-cell sequencing technologies researchers are provided with the resource to delineate specific biomarkers associated with reactive astrocytes in AD. In this review, we will focus on the role of astrocytes in normal conditions and the pathological development of AD. We will further review recent developments in the understanding of astrocyte heterogeneity and associated biomarkers. A better understanding of astrocyte contributions and phenotypic changes in AD can ultimately lead to more effective therapeutic targets.

11.
Mol Psychiatry ; 26(12): 7803-7812, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34385598

RESUMO

Opioid use disorder (OUD) is a public health crisis in the U.S. that causes over 50 thousand deaths annually due to overdose. Using next-generation RNA sequencing and proteomics techniques, we identified 394 differentially expressed (DE) coding and long noncoding (lnc) RNAs as well as 213 DE proteins in Brodmann Area 9 of OUD subjects. The RNA and protein changes converged on pro-angiogenic gene networks and cytokine signaling pathways. Four genes (LGALS3, SLC2A1, PCLD1, and VAMP1) were dysregulated in both RNA and protein. Dissecting these DE genes and networks, we found cell type-specific effects with enrichment in astrocyte, endothelial, and microglia correlated genes. Weighted-genome correlation network analysis (WGCNA) revealed cell-type correlated networks including an astrocytic/endothelial/microglia network involved in angiogenic cytokine signaling as well as a neuronal network involved in synaptic vesicle formation. In addition, using ex vivo magnetic resonance imaging, we identified increased vascularization in postmortem brains from a subset of subjects with OUD. This is the first study integrating dysregulation of angiogenic gene networks in OUD with qualitative imaging evidence of hypervascularization in postmortem brain. Understanding the neurovascular effects of OUD is critical in this time of widespread opioid use.


Assuntos
Overdose de Drogas , Transtornos Relacionados ao Uso de Opioides , RNA Longo não Codificante , Autopsia , Encéfalo/diagnóstico por imagem , Encéfalo/metabolismo , Citocinas , Redes Reguladoras de Genes/genética , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Neovascularização Patológica , Transtornos Relacionados ao Uso de Opioides/genética , Proteômica , RNA Longo não Codificante/genética , Transdução de Sinais
12.
Sci Data ; 8(1): 175, 2021 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-34267212

RESUMO

Spinal cord injury disrupts ascending and descending neural signals causing sensory and motor dysfunction. Neuromodulation with electrical stimulation is used in both clinical and research settings to induce neural plasticity and improve functional recovery following spinal trauma. However, the mechanisms by which electrical stimulation affects recovery remain unclear. In this study we examined the effects of cortical electrical stimulation following injury on transcription at several levels of the central nervous system. We performed a unilateral, incomplete cervical spinal contusion injury in rats and delivered stimulation for one week to the contralesional motor cortex to activate the corticospinal tract and other pathways. RNA was purified from bilateral subcortical white matter and 3 levels of the spinal cord. Here we provide the complete data set in the hope that it will be useful for researchers studying electrical stimulation as a therapy to improve recovery from the deficits associated with spinal cord injury.


Assuntos
Estimulação Elétrica , Tratos Piramidais/metabolismo , Traumatismos da Coluna Vertebral/genética , Transcriptoma , Substância Branca/metabolismo , Animais , Terapia por Estimulação Elétrica , Feminino , Plasticidade Neuronal , Ratos , Ratos Long-Evans , Traumatismos da Coluna Vertebral/terapia
13.
BMC Biol ; 19(1): 132, 2021 06 25.
Artigo em Inglês | MEDLINE | ID: mdl-34172044

RESUMO

BACKGROUND: Oligodendrocytes, responsible for axon ensheathment, are critical for central nervous system (CNS) development, function, and diseases. OLIG2 is an important transcription factor (TF) that acts during oligodendrocyte development and performs distinct functions at different stages. Previous studies have shown that lncRNAs (long non-coding RNAs; > 200 bp) have important functions during oligodendrocyte development, but their roles have not been systematically characterized and their regulation is not yet clear. RESULTS: We performed an integrated study of genome-wide OLIG2 binding and the epigenetic modification status of both coding and non-coding genes during three stages of oligodendrocyte differentiation in vivo: neural stem cells (NSCs), oligodendrocyte progenitor cells (OPCs), and newly formed oligodendrocytes (NFOs). We found that 613 lncRNAs have OLIG2 binding sites and are expressed in at least one cell type, which can potentially be activated or repressed by OLIG2. Forty-eight of them have increased expression in oligodendrocyte lineage cells. Predicting lncRNA functions by using a "guilt-by-association" approach revealed that the functions of these 48 lncRNAs were enriched in "oligodendrocyte development and differentiation." Additionally, bivalent genes are known to play essential roles during embryonic stem cell differentiation. We identified bivalent genes in NSCs, OPCs, and NFOs and found that some bivalent genes bound by OLIG2 are dynamically regulated during oligodendrocyte development. Importantly, we unveiled a previously unknown mechanism that, in addition to transcriptional regulation via DNA binding, OLIG2 could self-regulate through the 3' UTR of its own mRNA. CONCLUSIONS: Our studies have revealed the missing links in the mechanisms regulating oligodendrocyte development at the transcriptional level and after transcription. The results of our research have improved the understanding of fundamental cell fate decisions during oligodendrocyte lineage formation, which can enable insights into demyelination diseases and regenerative medicine.


Assuntos
Oligodendroglia , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Diferenciação Celular/genética , Linhagem da Célula/genética , Proteínas do Tecido Nervoso/genética , RNA Longo não Codificante/genética
14.
Cell Rep ; 34(5): 108721, 2021 02 02.
Artigo em Inglês | MEDLINE | ID: mdl-33535036

RESUMO

Spinal cord injury (SCI) is one of the most devastating neural injuries without effective therapeutic solutions. Astrocytes are the predominant component of the scar. Understanding the complex contributions of reactive astrocytes to SCI pathophysiologies is fundamentally important for developing therapeutic strategies. We have studied the molecular changes in the injury environment and the astrocyte-specific responses by astrocyte purification from injured spinal cords from acute to chronic stages. In addition to protein-coding genes, we have systematically analyzed the expression profiles of long non-coding RNAs (lncRNAs) (>200 bp), which are regulatory RNAs that play important roles in the CNS. We have identified a highly conserved lncRNA, Zeb2os, and demonstrated using functional assays that it plays an important role in reactive astrogliosis through the Zeb2os/Zeb2/Stat3 axis. These studies provide valuable insights into the molecular basis of reactive astrogliosis and fill the knowledge gap regarding the function(s) of lncRNAs in astrogliosis and SCI.


Assuntos
Astrócitos/metabolismo , Gliose/metabolismo , RNA Longo não Codificante/metabolismo , Animais , Humanos , Camundongos , Traumatismos da Medula Espinal/fisiopatologia
15.
J Comp Neurol ; 529(5): 1066-1080, 2021 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-32783205

RESUMO

BMAL1 is a core component of the mammalian circadian clockwork. Removal of BMAL1 from the retina significantly affects visual information processing in both rod and cone pathways. To identify potential pathways and/or molecules through which BMAL1 alters signal transmission at the cone pedicle, we performed an RNA-seq differential expression analysis between cone-specific Bmal1 knockout cones (cone-Bmal1-/- ) and wild-type (WT) cones. We found 88 genes differentially expressed. Among these, Complexin3 (Cplx3), a SNARE regulator at ribbon synapses, was downregulated fivefold in the mutant cones. The purpose of this work was to determine whether BMAL1 and/or the cone clock controls CPLX3 protein expression at cone pedicles. We found that CPLX3 expression level was decreased twofold in cone-Bmal1-/- cones. Furthermore, CPLX3 expression was downregulated at night compared to the day in WT cones but remained constitutively low in mutant cones both day and night. The transcript and protein expression levels of Cplx4-the other complexin expressed in cones-were similar in WT and mutant cones; in WT cones, CPLX4 protein level did not change with the time of day. In silico analysis revealed four potential BMAL1:CLOCK binding sites upstream from exon one of Cplx3 and none upstream of exon one of Cplx4. Our results suggest that CPLX3 expression is regulated at the transcriptional level by the cone clock. The modulation of CPLX3 may be a mechanism by which the clock controls the cone synaptic transfer function to second-order cells and thereby impacts retinal signal processing during the day/night cycle.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/fisiologia , Relógios Circadianos/fisiologia , Proteínas do Tecido Nervoso/fisiologia , Células Fotorreceptoras Retinianas Cones/fisiologia , Proteínas SNARE/fisiologia , Fatores de Transcrição ARNTL/deficiência , Fatores de Transcrição ARNTL/genética , Fatores de Transcrição ARNTL/fisiologia , Proteínas Adaptadoras de Transporte Vesicular/biossíntese , Proteínas Adaptadoras de Transporte Vesicular/genética , Animais , Regulação para Baixo , Feminino , Masculino , Camundongos , Camundongos Knockout , Regiões Promotoras Genéticas/genética , RNA Mensageiro/biossíntese , RNA Mensageiro/genética , RNA-Seq , Pigmentos da Retina/genética , Rodopsinas Sensoriais/genética , Transdução de Sinais/fisiologia
16.
Malar J ; 19(1): 281, 2020 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-32758218

RESUMO

BACKGROUND: In the Greater Mekong sub-region, Plasmodium vivax has become the predominant species and imposes a major challenge for regional malaria elimination. This study aimed to investigate the variations in genes potentially related to drug resistance in P. vivax populations from the China-Myanmar border area. In addition, this study also wanted to determine whether divergence existed between parasite populations associated with asymptomatic and acute infections. METHODS: A total of 66 P. vivax isolates were obtained from patients with acute malaria who attended clinics at the Laiza area, Kachin State, Myanmar in 2015. In addition, 102 P. vivax isolates associated with asymptomatic infections were identified by screening of volunteers without signs or symptoms from surrounding villages. Slide-positive samples were verified with nested PCR detecting the 18S rRNA gene. Multiclonal infections were further excluded by genotyping at msp-3α and msp-3ß genes. Parasite DNA from 60 symptomatic cases and 81 asymptomatic infections was used to amplify and sequence genes potentially associated with drug resistance, including pvmdr1, pvcrt-o, pvdhfr, pvdhps, and pvk12. RESULTS: The pvmdr1 Y976F and F1076L mutations were present in 3/113 (2.7%) and 97/113 (85.5%) P. vivax isolates, respectively. The K10 insertion in pvcrt-o gene was found in 28.2% of the parasites. Four mutations in the two antifolate resistance genes reached relatively high levels of prevalence: pvdhfr S58R (53.4%), S117N/T (50.8%), pvdhps A383G (75.0%), and A553G (36.3%). Haplotypes with wild-type pvmdr1 (976Y/997K/1076F) and quadruple mutations in pvdhfr (13I/57L/58R/61M/99H/117T/173I) were significantly more prevalent in symptomatic than asymptomatic infections, whereas the pvmdr1 mutant haplotype 976Y/997K/1076L was significantly more prevalent in asymptomatic than symptomatic infections. In addition, quadruple mutations at codons 57, 58, 61 and 117 of pvdhfr and double mutations at codons 383 and 553 of pvdhps were found both in asymptomatic and symptomatic infections with similar frequencies. No mutations were found in the pvk12 gene. CONCLUSIONS: Mutations in pvdhfr and pvdhps were prevalent in both symptomatic and asymptomatic P. vivax infections, suggestive of resistance to antifolate drugs. Asymptomatic carriers may act as a silent reservoir sustaining drug-resistant parasite transmission necessitating a rational strategy for malaria elimination in this region.


Assuntos
Antimaláricos/administração & dosagem , Resistência a Medicamentos/genética , Marcadores Genéticos , Malária Vivax/parasitologia , Plasmodium vivax/genética , Proteínas de Protozoários/genética , Adolescente , Adulto , Infecções Assintomáticas , Criança , Feminino , Humanos , Masculino , Proteínas de Membrana Transportadoras/análise , Proteínas Associadas à Resistência a Múltiplos Medicamentos/análise , Mianmar , Plasmodium vivax/efeitos dos fármacos , Proteínas de Protozoários/análise , Análise de Sequência de DNA , Adulto Jovem
17.
Sci Adv ; 6(28): eaba7232, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32832605

RESUMO

Mouse photoreceptors are electrically coupled via gap junctions, but the relative importance of rod/rod, cone/cone, or rod/cone coupling is unknown. Furthermore, while connexin36 (Cx36) is expressed by cones, the identity of the rod connexin has been controversial. We report that FACS-sorted rods and cones both express Cx36 but no other connexins. We created rod- and cone-specific Cx36 knockout mice to dissect the photoreceptor network. In the wild type, Cx36 plaques at rod/cone contacts accounted for more than 95% of photoreceptor labeling and paired recordings showed the transjunctional conductance between rods and cones was ~300 pS. When Cx36 was eliminated on one side of the gap junction, in either conditional knockout, Cx36 labeling and rod/cone coupling were almost abolished. We could not detect direct rod/rod coupling, and cone/cone coupling was minor. Rod/cone coupling is so prevalent that indirect rod/cone/rod coupling via the network may account for previous reports of rod coupling.

18.
Nanomedicine ; 29: 102271, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32702466

RESUMO

Mammalian small extracellular vesicles (sEVs) can deliver diverse molecules to target cells. However, they are difficult to obtain in large quantities and can activate host immune responses. Plant-derived vesicles may help to overcome these challenges. We optimized isolation methods for two types of plant vesicles, nanovesicles from disrupted leaf and sEVs from the extracellular apoplastic space of Arabidopsis thaliana. Both preparations yielded intact vesicles of uniform size, and a mean membrane charge of approximately -25 mV. We also demonstrated applicability of these preparative methods using Brassicaceae vegetables. Proteomic analysis of a subset of vesicles with a density of 1.1-1.19 g mL-1 sheds light on the likely cellular origin and complexity of the vesicles. Both leaf nanovesicles and sEVs were taken up by cancer cells, with sEVs showing an approximately three-fold higher efficiency compared to leaf nanovesicles. These results support the potential of plant-derived vesicles as vehicles for therapeutic delivery.


Assuntos
Arabidopsis/química , Sistemas de Liberação de Medicamentos , Vesículas Extracelulares/química , Folhas de Planta/química , Arabidopsis/genética , Vesículas Extracelulares/genética , Humanos , Folhas de Planta/genética , Proteômica/métodos
19.
IEEE/ACM Trans Comput Biol Bioinform ; 17(5): 1493-1503, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31425044

RESUMO

Although plenty of structural variant detecting approaches for human genomes can be looked up in the literatures, little has been acknowledged on the effectiveness of those structural variant softwares for plant genomes. Moreover, it has been demonstrated frequent occurrences for those structural variant detecting softwares to find too many false structural variants. In this paper, we devote to detect deletions, insertions, and inversions, in total of three kinds of structural variants occurring in Hedou12 genome in contrast to Williams82 genome. To find more potential structural variants, we try to develop new principles to detect discordant and split read map sets supporting structural variants. Aiming to enhance the precision of structural variant detections, we propose two new sequencing characteristic based probability models, which use the sequencing parameters of Hedou12 genome as well as the parameters for Hedou12 paired-end reads to be aligned onto Williams82, to evaluate the probability for a potential structural variant to occur in. To remove the false members from those potential structural variants, we propose a set cover problem model to describe formally on which potential structural variants it should accept to achieve as high as possible a probability summation. This will achieve a solution with more credible structural variants, which can be verified by comparing with DELLY version 0.5.8 and LUMPY version 0.2.2.3. Our algorithm has been verified to be able to find deletions, insertions, and inversions in Hedou12 in contrast to Williams82 DELLY as well as LUMPY fails to find.


Assuntos
Genoma de Planta/genética , Variação Estrutural do Genoma/genética , Genômica/métodos , Software , Algoritmos , Deleção de Genes , Mutagênese Insercional/genética , Análise de Sequência de DNA , Inversão de Sequência/genética , Glycine max/genética
20.
Genes (Basel) ; 10(9)2019 09 09.
Artigo em Inglês | MEDLINE | ID: mdl-31505774

RESUMO

The emergence and spread of drug resistance is a problem hindering malaria elimination in Southeast Asia. In this study, genetic variations in drug resistance markers of Plasmodium falciparum were determined in parasites from asymptomatic populations located in three geographically dispersed townships of Myanmar by PCR and sequencing. Mutations in dihydrofolate reductase (pfdhfr), dihydropteroate synthase (pfdhps), chloroquine resistance transporter (pfcrt), multidrug resistance protein 1 (pfmdr1), multidrug resistance-associated protein 1 (pfmrp1), and Kelch protein 13 (k13) were present in 92.3%, 97.6%, 84.0%, 98.8%, and 68.3% of the parasites, respectively. The pfcrt K76T, pfmdr1 N86Y, pfmdr1 I185K, and pfmrp1 I876V mutations were present in 82.7%, 2.5%, 87.5%, and 59.8% isolates, respectively. The most prevalent haplotypes for pfdhfr, pfdhps, pfcrt and pfmdr1 were 51I/59R/108N/164L, 436A/437G/540E/581A, 74I/75E/76T/220S/271E/326N/356T/371I, and 86N/130E/184Y/185K/1225V, respectively. In addition, 57 isolates had three different point mutations (K191T, F446I, and P574L) and three types of N-terminal insertions (N, NN, NNN) in the k13 gene. In total, 43 distinct haplotypes potentially associated with multidrug resistance were identified. These findings demonstrate a high prevalence of multidrug-resistant P. falciparum in asymptomatic infections from diverse townships in Myanmar, emphasizing the importance of targeting asymptomatic infections to prevent the spread of drug-resistant P.falciparum.


Assuntos
Antimaláricos/farmacologia , Resistência a Múltiplos Medicamentos , Malária/parasitologia , Plasmodium falciparum/genética , Polimorfismo Genético , Di-Hidropteroato Sintase/genética , Humanos , Malária/epidemiologia , Proteínas Associadas à Resistência a Múltiplos Medicamentos/genética , Mianmar , Plasmodium falciparum/efeitos dos fármacos , Plasmodium falciparum/patogenicidade , Proteínas de Protozoários/genética , Tetra-Hidrofolato Desidrogenase/genética
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...