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1.
Anal Chim Acta ; 1287: 342133, 2024 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-38182397

RESUMO

Although the research on nanozymes has attracted widespread attention in recent years, the development of highly active and multifunctional nanozymes remains a challenge. Here, a bifunctional AMP-Cu nanozyme with laccase- and catecholase-like activities was successfully prepared at room temperature with Cu2+ as the metal ion and adenosine-5'-monophosphate (AMP) as the ligand molecule. Based on the excellent catalytic performance of AMP-Cu, a three-channel colorimetric sensor array was constructed using reaction kinetics as the sensing unit to achieve high-throughput detection and identification of six common phenolic compounds at low concentrations. This strategy simplifies the construction of sensor array and demonstrates the capacity to obtain multidimensional data from a single material. Finally, with the assistance of smartphones and homemade dark boxes, a portable on-site detection method for phenolic compounds was developed. This work would contribute to the development of portable sensors and the highly efficient identification of phenolic compounds in complex samples.


Assuntos
Colorimetria , Smartphone , Catálise , Cinética , Lacase , Fenóis
2.
Curr Mol Med ; 2024 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-38204278

RESUMO

The stomach is a crucial digestive organ in the human body, highly susceptible to inflammation or pathogen invasion, which can lead to various gastric diseases, including gastric cancer. Toll-like receptors (TLRs) are the first line of defense against pathogen invasion. TLR4, a member of the TLRs family, recognizes pathogen and danger-related molecular patterns to induce inflammatory responses. Helicobacter pylori (H. pylori) is a significant factor in gastric health, and TLR4 recognizes H. pylori -LPS to trigger an inflammatory response. Downstream TLR4 signaling generates proinflammatory cytokines that initiate inflammation in the gastric mucosa. In addition, TLR4 gene polymorphisms can increase health risks. This study aims to investigate the contribution of TLR4 to the inflammatory response in gastric diseases and the relation between TLR4 and H. pylori, TLR4 gene polymorphisms, and how TLR4 affects gastric diseases' possible pathways to provide further insight for future prevention and clinical treatment strategies.

3.
Analyst ; 148(10): 2375-2386, 2023 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-37129055

RESUMO

Carbon dots (CDs) with red fluorescence emission are highly desirable for use in bioimaging and trace- substance detection, with potential applications in biotherapy, photothermal therapy, and tumor visualization. Most CDs emit green or blue fluorescence, thus limiting their applicability. We report a novel fluorescent detection platform based on high-brightness red fluorescence emission carbon dots (R-CDs) co-doped with nitrogen and bromine, which exhibit pH and oxidized L-glutathione (GSSG) dual-responsive characteristics. The absolute quantum yield of the R-CDs was as high as 11.93%. We discovered that the R-CDs were able to detect acidic pH in live cells and zebrafish owing to protonation and deprotonation. In addition, GSSG was detected in vitro over a broad linear range (8-200 µM) using the R-CDs with excitation-independent emission. Furthermore, cell imaging and bioimaging experiments demonstrated that the R-CDs were highly cytocompatible and could be used as fluorescent probes to target lysosomes and nucleolus. These studies highlight the promising prospects of R-CDs as biosensing tools for bioimaging and trace-substance detection applications.


Assuntos
Pontos Quânticos , Animais , Dissulfeto de Glutationa , Pontos Quânticos/química , Carbono/química , Peixe-Zebra , Corantes Fluorescentes/química , Nitrogênio/química , Concentração de Íons de Hidrogênio
4.
Autoimmunity ; 56(1): 2174531, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-36762543

RESUMO

Gastric cancer (GC) is a type of the most common cancers. Autoimmune gastritis (AIG) and infection with Helicobacter pylori (HP) are the risk factors of triggering GC. With the emphasis on the treatment of HP, the incidence and prevalence of HP infection in population is decreasing. However, AIG lacks accurate diagnosis and treatment methods, which occupies high cancer risk factors. AIG is controlled by the immune environment of the stomach, including immune cells, inflammatory cells, and infiltrating intercellular material. Various immune cells or cytokines play a central role in the process of regulating gastric parietal cells. Abnormal expression levels of cytokines involved in immunity are bound to face the risk of tumorigenesis. Therefore, it is particularly important for preventing or treating AIG and avoiding the risk of gastric cancer to clarify the confirmed action mode of immune cells and cytokines in the gastric system. Herein, we briefly reviewed the role of the immune environment under AIG, focussing on describing these double-edged effects between immune cells and cytokines, and pointing out potential research challenges.


Assuntos
Doenças Autoimunes , Gastrite , Helicobacter pylori , Neoplasias Gástricas , Humanos , Citocinas/metabolismo , Gastrite/epidemiologia , Gastrite/etiologia , Células Parietais Gástricas/metabolismo , Helicobacter pylori/metabolismo
5.
Nucleic Acids Res ; 51(D1): D853-D860, 2023 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-36161321

RESUMO

Single-cell studies have delineated cellular diversity and uncovered increasing numbers of previously uncharacterized cell types in complex tissues. Thus, synthesizing growing knowledge of cellular characteristics is critical for dissecting cellular heterogeneity, developmental processes and tumorigenesis at single-cell resolution. Here, we present Cell Taxonomy (https://ngdc.cncb.ac.cn/celltaxonomy), a comprehensive and curated repository of cell types and associated cell markers encompassing a wide range of species, tissues and conditions. Combined with literature curation and data integration, the current version of Cell Taxonomy establishes a well-structured taxonomy for 3,143 cell types and houses a comprehensive collection of 26,613 associated cell markers in 257 conditions and 387 tissues across 34 species. Based on 4,299 publications and single-cell transcriptomic profiles of ∼3.5 million cells, Cell Taxonomy features multifaceted characterization for cell types and cell markers, involving quality assessment of cell markers and cell clusters, cross-species comparison, cell composition of tissues and cellular similarity based on markers. Taken together, Cell Taxonomy represents a fundamentally useful reference to systematically and accurately characterize cell types and thus lays an important foundation for deeply understanding and exploring cellular biology in diverse species.

6.
Nucleic Acids Res ; 50(D1): D1131-D1138, 2022 01 07.
Artigo em Inglês | MEDLINE | ID: mdl-34718720

RESUMO

Brain is the central organ of the nervous system and any brain disease can seriously affect human health. Here we present BrainBase (https://ngdc.cncb.ac.cn/brainbase), a curated knowledgebase for brain diseases that aims to provide a whole picture of brain diseases and associated genes. Specifically, based on manual curation of 2768 published articles along with information retrieval from several public databases, BrainBase features comprehensive collection of 7175 disease-gene associations spanning a total of 123 brain diseases and linking with 5662 genes, 16 591 drug-target interactions covering 2118 drugs/chemicals and 623 genes, and five types of specific genes in light of expression specificity in brain tissue/regions/cerebrospinal fluid/cells. In addition, considering the severity of glioma among brain tumors, the current version of BrainBase incorporates 21 multi-omics datasets, presents molecular profiles across various samples/conditions and identifies four groups of glioma featured genes with potential clinical significance. Collectively, BrainBase integrates not only valuable curated disease-gene associations and drug-target interactions but also molecular profiles through multi-omics data analysis, accordingly bearing great promise to serve as a valuable knowledgebase for brain diseases.


Assuntos
Encefalopatias/genética , Biologia Computacional , Bases de Dados Genéticas , Encefalopatias/classificação , Glioma/genética , Glioma/patologia , Humanos , Bases de Conhecimento
7.
ACS Appl Mater Interfaces ; 14(1): 1-19, 2022 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-34939784

RESUMO

Compared with traditional internal fixation devices, bone adhesives are expected to exhibit remarkable advantages, such as improved fixation of comminuted fractures and maintained spatial location of fractured scattered bone pieces in treating bone injuries. In this review, different bone adhesives are summarized from the aspects of bone tissue engineering, and the applications of bone adhesives are emphasized. The concepts of "liquid scaffold" and "liquid plate" are proposed to summarize two different research directions of bone adhesives. Furthermore, significant advances of bone adhesives in recent years in mechanical strength, osseointegration, osteoconductivity, and osteoinductivity are discussed. We conclude this topic by providing perspectives on the state-of-the-art research progress and future development trends of bone adhesives. We hope this review will provide a comprehensive summary of bone adhesives and inspire more extensive and in-depth research on this subject.


Assuntos
Consolidação da Fratura/efeitos dos fármacos , Fraturas Ósseas/tratamento farmacológico , Substâncias Macromoleculares/farmacologia , Adesivos Teciduais/farmacologia , Animais , Regeneração Óssea/efeitos dos fármacos , Osso e Ossos/efeitos dos fármacos , Linhagem Celular Tumoral , Humanos , Substâncias Macromoleculares/química , Osseointegração/efeitos dos fármacos , Adesivos Teciduais/química , Engenharia Tecidual , Alicerces Teciduais/química
8.
Artigo em Inglês | MEDLINE | ID: mdl-31867319

RESUMO

Many biological indicators related to chronological age have been proposed. Recent studies found that epigenetic clock or DNA methylation age is highly correlated with chronological age. In particular, a significant difference between DNA methylation age (m-age) and chronological age was observed in cancers. However, the prediction and characterization of m-age in pan-cancer remains an explored area. In this study, 1,631 age-related methylation sites in normal tissues were discovered and analyzed. A comprehensive computational model named CancerClock was constructed to predict the m-age for normal samples based on methylation levels of the extracted methylation sites. LASSO linear regression model was used to screen and train the CancerClock model in normal tissues. The accuracy of CancerClock has proved to be 81%, and the correlation value between chronological age and m-age was 0.939 (P < 0.01). Next, CancerClock was used to evaluate the difference between m-age and chronological age for 33 cancer types from TCGA. There were significant differences between predicted m-age and chronological age in large number of cancer samples. These cancer samples were defined as "age-related cancer samples" and they have some differential methylation sites. The differences between predicted m-age and chronological age may contribute to cancer development. Some of these differential methylation sites were associated with cancer survival. CancerClock provided assistance in estimating the m-age in normal and cancer samples. The changes between m-age and chronological age may improve the diagnosis and prognosis of cancers.

9.
Pathol Res Pract ; 215(12): 152688, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31727503

RESUMO

Osteosarcoma (OS) is known as a tumor that derives from skeletal system with increasing incidence worldwide. This study aimed to explore the effect of a circular RNA (circRNA), circ_0102049, on OS and reveal its potential molecular mechanism. In this work, the expression of circ_0102049 was detected by quantitative real time polymerase chain reaction (qRT-RCR) in both OS specimens and cell lines. The relationship between circ_0102049 level and patients' overall survival was evaluated by Kaplan-Meier curves and Cox regression analysis. Cell proliferation, apoptosis, migration and invasion of U2OS and MG63 cells were measured by cell counting kit-8 (CCK-8), flow cytometry, wound healing and transwell experiments, respectively. In addition, subcellular fractionation, bioinformatics analysis and dual-luciferase reporter assay were utilized to reveal the mechanism of circ_0102049 in OS. Circ_0102049 was overexpressed in both OS specimens and cells. Moreover, the level of circ_0102049 in OS patients was markedly correlated with larger tumor size, pulmonary metastasis and poor prognosis. Circ_0102049 remarkably accelerated cell proliferation, migration and invasion but attenuated cell apoptosis in OS cells analyzed by gain/loss of function experiments. What's more, we identified that circ_0102049 functions as a competing endogenous RNA (ceRNA) to competitively sponge miR-1304-5p to upregulate MDM2 expression at posttranscriptional level, thus mediating the cellular behaviors of OS cells. Collectively, our study provides an innovatively regulatory mechanism of circ_0102049 in OS and points out a new way for OS treatment.


Assuntos
Neoplasias Ósseas/metabolismo , MicroRNAs/metabolismo , Osteossarcoma/metabolismo , Proteínas Proto-Oncogênicas c-mdm2/metabolismo , RNA Circular/metabolismo , Adulto , Apoptose , Neoplasias Ósseas/genética , Neoplasias Ósseas/mortalidade , Neoplasias Ósseas/patologia , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Masculino , MicroRNAs/genética , Invasividade Neoplásica , Osteossarcoma/genética , Osteossarcoma/mortalidade , Osteossarcoma/patologia , Proteínas Proto-Oncogênicas c-mdm2/genética , RNA Circular/genética , Transdução de Sinais , Carga Tumoral
10.
Cell ; 175(7): 1931-1945.e18, 2018 12 13.
Artigo em Inglês | MEDLINE | ID: mdl-30550790

RESUMO

Mosquito-borne flaviviruses, including dengue virus (DENV) and Zika virus (ZIKV), are a growing public health concern. Systems-level analysis of how flaviviruses hijack cellular processes through virus-host protein-protein interactions (PPIs) provides information about their replication and pathogenic mechanisms. We used affinity purification-mass spectrometry (AP-MS) to compare flavivirus-host interactions for two viruses (DENV and ZIKV) in two hosts (human and mosquito). Conserved virus-host PPIs revealed that the flavivirus NS5 protein suppresses interferon stimulated genes by inhibiting recruitment of the transcription complex PAF1C and that chemical modulation of SEC61 inhibits DENV and ZIKV replication in human and mosquito cells. Finally, we identified a ZIKV-specific interaction between NS4A and ANKLE2, a gene linked to hereditary microcephaly, and showed that ZIKV NS4A causes microcephaly in Drosophila in an ANKLE2-dependent manner. Thus, comparative flavivirus-host PPI mapping provides biological insights and, when coupled with in vivo models, can be used to unravel pathogenic mechanisms.


Assuntos
Vírus da Dengue , Dengue , Proteínas de Membrana , Proteínas Nucleares , Proteínas não Estruturais Virais , Infecção por Zika virus , Zika virus , Animais , Linhagem Celular Tumoral , Culicidae , Dengue/genética , Dengue/metabolismo , Dengue/patologia , Vírus da Dengue/genética , Vírus da Dengue/metabolismo , Vírus da Dengue/patogenicidade , Células HEK293 , Humanos , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Mapeamento de Interação de Proteínas , Proteínas não Estruturais Virais/genética , Proteínas não Estruturais Virais/metabolismo , Zika virus/genética , Zika virus/metabolismo , Zika virus/patogenicidade , Infecção por Zika virus/genética , Infecção por Zika virus/metabolismo , Infecção por Zika virus/patologia
11.
Injury ; 49(6): 1215-1219, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29655591

RESUMO

Treatment of tibial plateau fractures associated with anterior cruciate ligament (ACL) injuries can be challenging. Maintaining the joint surface and axis are two main principles for the management of patients with tibial plateau fractures. Herein, we describe a patient with tibial plateau fracture of Schatzker type VI associated with complete ACL rupture. Although in a two-stage reconstruction surgery for treatment of its rupture seem to be accepted by most orthopaedic surgeons in cases of ACL injuries, we treated our patient with ORIF in a one-stage ACL reconstruction surgery. At the 1-year follow-up, the patient gained full range of motion and was functioning well. We reviewed the literature on performing ORIF in a one-stage ACL reconstruction for the treatment of tibial plateau fractures, which seemed to be a reasonable management approach that supported its use for the treatment of this patient.


Assuntos
Lesões do Ligamento Cruzado Anterior/cirurgia , Reconstrução do Ligamento Cruzado Anterior , Traumatismos do Joelho/cirurgia , Articulação do Joelho/fisiopatologia , Redução Aberta , Fraturas da Tíbia/cirurgia , Adulto , Lesões do Ligamento Cruzado Anterior/diagnóstico por imagem , Lesões do Ligamento Cruzado Anterior/fisiopatologia , Humanos , Traumatismos do Joelho/diagnóstico por imagem , Traumatismos do Joelho/fisiopatologia , Articulação do Joelho/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Radiografia , Amplitude de Movimento Articular , Fraturas da Tíbia/diagnóstico por imagem , Fraturas da Tíbia/fisiopatologia , Resultado do Tratamento
12.
Technol Health Care ; 25(4): 803-808, 2017 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-28436402

RESUMO

Publications describing the diagnosis and treatment of anterior dislocation of the sacroiliac joint are scarce. We report the case a 19-year-old female at 8 weeks' gestation who presented with anterior fracture dislocation of the right sacroiliac joint, posterior fracture dislocation of the left sacroiliac joint (crescent fracture), and incomplete abortion resulting from high energy trauma. Orthopedic surgery involved standard anterior sacroiliac joint plating using an ilioinguinal approach combined with a modified Stoppa approach. Three attempts at complete abortion failed. Complete abortion was eventually achieved by dilatation and curettage two weeks after orthopedic surgery. Our findings reveal a need to improve techniques for diagnosis and treatment of anterior fracture dislocation of the sacroiliac joint, so greater attention can be paid to the rapid and effective management of associated comorbidities, and those resulting from the initial trauma.


Assuntos
Fratura-Luxação/cirurgia , Fixação Interna de Fraturas/métodos , Articulação Sacroilíaca/cirurgia , Aborto Induzido , Placas Ósseas , Feminino , Humanos , Gravidez , Adulto Jovem
13.
Oncol Res ; 25(1): 75-81, 2017 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-28081735

RESUMO

MicroRNAs (miRNAs) are small conserved RNAs regulating specific target genes in posttranscriptional levels. They have been involved in multiple processes of tumor progression, including cell proliferation. miR-214-5p (also miR-214*) is a newly identified miRNA, and its functions are largely unknown. In this study, we explore the role of miR-214-5p in the proliferation and invasion of human osteosarcoma (OS) cells. The results showed that miR-214-5p was sharply reduced in OS tissues and cell lines, compared with normal tissues and cell lines. In addition, the miR-214-5p mimic greatly increased the miR-214-5p level and significantly decreased the proliferation and invasion of HOS and G293 OS cells. In contrast, the miR-214-5p inhibitor had a completely opposite effect on the miR-214-5p level, cell proliferation, and cell invasion. Moreover, bioinformatics and luciferase reporter gene assays confirmed that miR-1908 targeted the mRNA 3'-UTR region of ROCK1, a characterized tumor promoter in OS. In conclusion, miR-214-5p was identified as a new tumor suppressor, which directly targeted ROCK1 and suppressed proliferation of human OS cells.


Assuntos
Neoplasias Ósseas/genética , Regulação Neoplásica da Expressão Gênica , MicroRNAs/genética , Osteossarcoma/genética , Interferência de RNA , Quinases Associadas a rho/genética , Regiões 3' não Traduzidas , Sequência de Bases , Sítios de Ligação , Neoplasias Ósseas/patologia , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Humanos , Osteossarcoma/patologia
14.
Oncol Res ; 25(1): 83-91, 2017 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-28081736

RESUMO

RASSF4, a member of the RASSF family, is broadly expressed in normal tissues but often inactivated in human cancers. Despite various studies on RASSF4, its role in osteosarcoma remains unclear. Therefore, in this study, we investigated the effects of RASSF4 expression on osteosarcoma cells and explored the underlying mechanism. The results of our study showed that RASSF4 was lowly expressed in osteosarcoma tissues and cells. RASSF4 overexpression significantly inhibited proliferation, migration, and invasion as well as the EMT process in osteosarcoma cells. Meanwhile, we found that RASSF4 overexpression markedly decreased the protein expression of ß-catenin, cyclin D1, and c-Myc in osteosarcoma cells. In conclusion, our findings showed that RASSF4 overexpression inhibits proliferation, invasion, EMT, and Wnt signaling pathway in osteosarcoma cells. Thus, RASSF4 may be considered a novel target for osteosarcoma treatment.


Assuntos
Neoplasias Ósseas/genética , Neoplasias Ósseas/metabolismo , Transição Epitelial-Mesenquimal/genética , Expressão Gênica , Osteossarcoma/genética , Osteossarcoma/metabolismo , Proteínas Supressoras de Tumor/genética , Via de Sinalização Wnt , Apoptose/genética , Neoplasias Ósseas/patologia , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Humanos , Osteossarcoma/patologia
15.
Virus Res ; 220: 172-8, 2016 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-27157859

RESUMO

Multigene-armed oncolytic adenoviruses are capable of efficiently generating a productive antitumor immune response. The chemokine (C-C motif) ligand 21 (CCL21) binds to CCR7 on naïve T cells and dendritic cells (DCs) to promote their chemoattraction to the tumor and resultant antitumor activity. Interleukin 21 (IL21) promotes survival of naïve T cells while maintaining their CCR7 surface expression, which increases their capacity to transmigrate in response to CCL21 chemoattraction. IL21 is also involved in NK cell differentiation and B cell activation and proliferation. The generation of effective antitumor immune responses is a complex process dependent upon coordinated interactions of various subsets of effector cells. Using the AdEasy system, we aimed to construct an oncolytic adenovirus co-expressing CCL21 and IL21 that could selectively replicate in TERTp-positive tumor cells (Ad-CCL21-IL21 virus). The E1A promoter of these oncolytic adenoviruses was replaced by telomerase reverse transcriptase promoter (TERTp). Ad-CCL21-IL21 was constructed from three plasmids, pGTE-IL21, pShuttle-CMV-CCL21 and AdEasy-1 and was homologously recombined and propagated in the Escherichia coli strain BJ5183 and the packaging cell line HEK-293, respectively. Our results showed that our targeted and armed oncolytic adenoviruses Ad-CCL21-IL21 can induce apoptosis in TERTp-positive tumor cells to give rise to viral propagation, in a dose-dependent manner. Importantly, we confirm that these modified oncolytic adenoviruses do not replicate efficiently in normal cells even under high viral loads. Additionally, we investigate the role of Ad-CCL21-IL21 in inducing antitumor activity and tumor specific cytotoxicity of CTLs in vitro. This study suggests that Ad-CCL21-IL21 is a promising targeted tumor-specific oncolytic adenovirus.


Assuntos
Adenoviridae/genética , Proteínas E1A de Adenovirus/genética , Quimiocina CCL21/genética , Interleucinas/genética , Vírus Oncolíticos/genética , Telomerase/genética , Adenoviridae/imunologia , Proteínas E1A de Adenovirus/imunologia , Células CACO-2 , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Quimiocina CCL21/imunologia , Técnicas de Cocultura , Células Epiteliais/citologia , Células Epiteliais/imunologia , Escherichia coli/genética , Escherichia coli/metabolismo , Células HEK293 , Células HT29 , Células HeLa , Recombinação Homóloga , Humanos , Interleucinas/imunologia , Masculino , Terapia Viral Oncolítica/métodos , Vírus Oncolíticos/imunologia , Plasmídeos/química , Plasmídeos/imunologia , Próstata/citologia , Próstata/imunologia , Linfócitos T Citotóxicos/citologia , Linfócitos T Citotóxicos/imunologia , Células THP-1 , Telomerase/imunologia
16.
Mol Biochem Parasitol ; 196(2): 90-9, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25176160

RESUMO

Phosphatidylcholine (PC) is the most abundant phospholipid in the membranes of the human parasite Leishmania. It is synthesized via two metabolic routes, the de novo pathway that starts with the uptake of choline, and the threefold methylation of phosphatidylethanolamine. Choline was shown to be dispensable for Leishmania; thus, the methylation pathway likely represents the primary route for PC production. Here, we have identified and characterized two phosphatidylethanolamine methyltransferases, LmjPEM1 and LmjPEM2. Both enzymes are expressed in promastigotes as well as in the vertebrate form amastigotes, suggesting that these methyltransferases are important for the development of the parasite throughout its life cycle. These enzymes are maximally expressed during the log phase of growth which correlates with the demand of PC synthesis during cell multiplication. Immunofluorescence studies combined with cell fractionation have shown that both methyltransferases are localized at the endoplasmic reticulum membrane. Heterologous expression in yeast has demonstrated that LmjPEM1 and LmjPEM2 complement the choline auxotrophy phenotype of a yeast double null mutant lacking phosphatidylethanolamine methyltransferase activity. LmjPEM1 catalyzes the first, and to a lesser extent, the second methylation reaction. In contrast, LmjPEM2 has the capacity to add the second and third methyl group onto phosphatidylethanolamine to yield (lyso)PC; it can also add the first methyl group, albeit with very low efficiency. Finally, we have demonstrated using inhibition studies with choline analogs that miltefosine and octadecyltrimethylammonium bromide are potent inhibitors of this metabolic pathway.


Assuntos
Colina/química , Leishmania major/enzimologia , Leishmaniose Cutânea/parasitologia , Fosfatidiletanolamina N-Metiltransferase/química , Proteínas de Protozoários/química , Animais , Colina/análogos & derivados , Humanos , Leishmania major/química , Leishmania major/genética , Leishmaniose Cutânea/metabolismo , Metilação , Camundongos , Fosfatidiletanolamina N-Metiltransferase/antagonistas & inibidores , Fosfatidiletanolamina N-Metiltransferase/genética , Fosfatidiletanolamina N-Metiltransferase/metabolismo , Fosfatidiletanolaminas/metabolismo , Proteínas de Protozoários/antagonistas & inibidores , Proteínas de Protozoários/genética , Proteínas de Protozoários/metabolismo
17.
Exp Parasitol ; 130(3): 200-4, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22306069

RESUMO

Ether glycerolipid biosynthesis in Leishmania major initiates with the acylation of dihydroxyacetonephosphate by the glycosomal dihydroxyacetonephosphate acyltransferase LmDAT. We previously reported that a null mutant of LmDAT is severely affected in logarithmic growth, survival during stationary phase, and in virulence in mice. In addition, it lacks all ether glycerolipids, produces altered forms of the ether-lipid based virulence factors lipophosphoglycan and increased levels of GPI-anchored protein gp63. Here, we describe the characterization of a compensatory mutant of a null strain of LmDAT, Δlmdat/Δlmdat(rev). Similarly to the null mutant, the Δlmdat/Δlmdat(rev) strain formed altered forms of lipophosphoglycan and increased levels of gp63, and was avirulent in mice infection. Further, dihydroxyacetonephosphate acyltransferase activity was absent in the revertant clone, indicating that a mutation in another acyltransferase gene did not confer dihydroxyacetonephosphate specificity. In contrast, the revertant grew normally but still exhibited poor survival during stationary phase. In addition, agarose gel analysis of its genomic DNA failed to detect any amplified DNA. Surprisingly, its sensitivity to aminoglycoside based antibiotics G418 and hygromycin was lower than that of the null mutant, wild type and complemented line.


Assuntos
Aciltransferases/genética , Antiprotozoários/farmacologia , Cinamatos/farmacologia , Gentamicinas/farmacologia , Higromicina B/análogos & derivados , Leishmania major/genética , Éteres Fosfolipídicos/metabolismo , Aciltransferases/metabolismo , Animais , Resistência a Medicamentos/genética , Amplificação de Genes , Glicoesfingolipídeos/metabolismo , Higromicina B/farmacologia , Leishmania major/efeitos dos fármacos , Leishmania major/crescimento & desenvolvimento , Leishmania major/metabolismo , Proteínas de Membrana/metabolismo , Metaloendopeptidases/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Mutação , Proteoglicanas/metabolismo , Proteínas de Protozoários/metabolismo , Virulência/genética
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