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1.
Mol Cell ; 76(1): 148-162.e7, 2019 10 03.
Artigo em Inglês | MEDLINE | ID: mdl-31447391

RESUMO

The rapid proliferation of cancer cells and dysregulated vasculature within the tumor leads to limited nutrient accessibility. Cancer cells often rewire their metabolic pathways for adaption to nutrient stress, and the underlying mechanism remains largely unknown. Glutamate dehydrogenase 1 (GDH1) is a key enzyme in glutaminolysis that converts glutamate to α-ketoglutarate (α-KG). Here, we show that, under low glucose, GDH1 is phosphorylated at serine (S) 384 and interacts with RelA and IKKß. GDH1-produced α-KG directly binds to and activates IKKß and nuclear factor κB (NF-κB) signaling, which promotes glucose uptake and tumor cell survival by upregulating GLUT1, thereby accelerating gliomagenesis. In addition, GDH1 S384 phosphorylation correlates with the malignancy and prognosis of human glioblastoma. Our finding reveals a unique role of α-KG to directly regulate signal pathway, uncovers a distinct mechanism of metabolite-mediated NF-κB activation, and also establishes the critical role of α-KG-activated NF-κB in brain tumor development.


Assuntos
Neoplasias Encefálicas/metabolismo , Proliferação de Células , Metabolismo Energético , Glioblastoma/metabolismo , Glucose/metabolismo , Glutamato Desidrogenase/metabolismo , Ácidos Cetoglutáricos/metabolismo , NF-kappa B/metabolismo , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patologia , Linhagem Celular Tumoral , Sobrevivência Celular , Criança , Feminino , Regulação Neoplásica da Expressão Gênica , Glioblastoma/genética , Glioblastoma/patologia , Glucose/deficiência , Transportador de Glucose Tipo 1/genética , Transportador de Glucose Tipo 1/metabolismo , Glutamato Desidrogenase/genética , Células HEK293 , Humanos , Quinase I-kappa B/genética , Quinase I-kappa B/metabolismo , Masculino , Camundongos Endogâmicos BALB C , Camundongos Nus , Pessoa de Meia-Idade , NF-kappa B/genética , Gradação de Tumores , Fosforilação , Transdução de Sinais , Fator de Transcrição RelA/genética , Fator de Transcrição RelA/metabolismo , Adulto Jovem
2.
EMBO J ; 41(11): e109272, 2022 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-35438208

RESUMO

Double-stranded DNA is recognized as a danger signal by cyclic guanosine monophosphate-adenosine monophosphate synthase (cGAS), triggering innate immune responses. Palmitoylation is an important post-translational modification (PTM) catalyzed by DHHC-palmitoyl transferases, which participate in the regulation of diverse biological processes. However, whether palmitoylation regulates cGAS function has not yet been explored. Here, we found that palmitoylation of cGAS at C474 restricted its enzymatic activity in the presence of double-stranded DNA. cGAS palmitoylation was catalyzed mainly by the palmitoyltransferase ZDHHC18 and double-stranded DNA promoted this modification. Mechanistically, palmitoylation of cGAS reduced the interaction between cGAS and double-stranded DNA, further inhibiting cGAS dimerization. Consistently, ZDHHC18 negatively regulated cGAS activation in human and mouse cell lines. In a more biologically relevant model system, Zdhhc18-deficient mice were found to be resistant to infection by DNA viruses, in agreement with the observation that ZDHHC18 negatively regulated cGAS mediated innate immune responses in human and mouse primary cells. In summary, the negative role of ZDHHC18-mediated cGAS palmitoylation may be a novel regulatory mechanism in the fine-tuning of innate immunity.


Assuntos
Lipoilação , Transdução de Sinais , Animais , Camundongos , DNA/metabolismo , Imunidade Inata , Nucleotidiltransferases/metabolismo , Transdução de Sinais/genética
3.
Mol Cell ; 71(2): 201-215.e7, 2018 07 19.
Artigo em Inglês | MEDLINE | ID: mdl-30029001

RESUMO

Macrophages are a dominant leukocyte population in the tumor microenvironment and actively promote cancer progression. However, the molecular mechanism underlying the role of macrophages remains poorly understood. Here we show that polarized M2 macrophages enhance 3-phosphoinositide-dependent protein kinase 1 (PDPK1)-mediated phosphoglycerate kinase 1 (PGK1) threonine (T) 243 phosphorylation in tumor cells by secreting interleukin-6 (IL-6). This phosphorylation facilitates a PGK1-catalyzed reaction toward glycolysis by altering substrate affinity. Inhibition of PGK1 T243 phosphorylation or PDPK1 in tumor cells or neutralization of macrophage-derived IL-6 abrogates macrophage-promoted glycolysis, proliferation, and tumorigenesis. In addition, PGK1 T243 phosphorylation correlates with PDPK1 activation, IL-6 expression, and macrophage infiltration in human glioblastoma multiforme (GBM). Moreover, PGK1 T243 phosphorylation also correlates with malignance and prognosis of human GBM. Our findings demonstrate a novel mechanism of macrophage-promoted tumor growth by regulating tumor cell metabolism, implicating the therapeutic potential to disrupt the connection between macrophages and tumor cells by inhibiting PGK1 phosphorylation.


Assuntos
Macrófagos/metabolismo , Fosfoglicerato Quinase/genética , Fosfoglicerato Quinase/metabolismo , Proteínas Quinases Dependentes de 3-Fosfoinositídeo/genética , Proteínas Quinases Dependentes de 3-Fosfoinositídeo/metabolismo , Animais , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/patologia , Carcinogênese/metabolismo , Linhagem Celular Tumoral , Proliferação de Células , Transformação Celular Neoplásica/metabolismo , Transformação Celular Neoplásica/patologia , Feminino , Glioblastoma/genética , Glioblastoma/metabolismo , Glioblastoma/patologia , Glicólise , Humanos , Macrófagos/patologia , Camundongos , Camundongos Nus , Mieloma Múltiplo/genética , Mieloma Múltiplo/metabolismo , Mieloma Múltiplo/patologia , Fosforilação , Prognóstico , Microambiente Tumoral
4.
Nature ; 571(7763): 127-131, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31243371

RESUMO

Cancer metastasis is the primary cause of morbidity and mortality, and accounts for up to 95% of cancer-related deaths1. Cancer cells often reprogram their metabolism to efficiently support cell proliferation and survival2,3. However, whether and how those metabolic alterations contribute to the migration of tumour cells remain largely unknown. UDP-glucose 6-dehydrogenase (UGDH) is a key enzyme in the uronic acid pathway, and converts UDP-glucose to UDP-glucuronic acid4. Here we show that, after activation of EGFR, UGDH is phosphorylated at tyrosine 473 in human lung cancer cells. Phosphorylated UGDH interacts with Hu antigen R (HuR) and converts UDP-glucose to UDP-glucuronic acid, which attenuates the UDP-glucose-mediated inhibition of the association of HuR with SNAI1 mRNA and therefore enhances the stability of SNAI1 mRNA. Increased production of SNAIL initiates the epithelial-mesenchymal transition, thus promoting the migration of tumour cells and lung cancer metastasis. In addition, phosphorylation of UGDH at tyrosine 473 correlates with metastatic recurrence and poor prognosis of patients with lung cancer. Our findings reveal a tumour-suppressive role of UDP-glucose in lung cancer metastasis and uncover a mechanism by which UGDH promotes tumour metastasis by increasing the stability of SNAI1 mRNA.


Assuntos
Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patologia , Metástase Neoplásica/genética , Metástase Neoplásica/prevenção & controle , Estabilidade de RNA , Fatores de Transcrição da Família Snail/genética , Uridina Difosfato Glucose/metabolismo , Animais , Linhagem Celular Tumoral , Movimento Celular , Proteína Semelhante a ELAV 1/deficiência , Proteína Semelhante a ELAV 1/genética , Proteína Semelhante a ELAV 1/metabolismo , Transição Epitelial-Mesenquimal , Feminino , Humanos , Neoplasias Pulmonares/enzimologia , Neoplasias Pulmonares/metabolismo , Camundongos , Camundongos Nus , Fosfotirosina/metabolismo , Prognóstico , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA Neoplásico/genética , RNA Neoplásico/metabolismo , Fatores de Transcrição da Família Snail/biossíntese , Uridina Difosfato Glucose Desidrogenase/química , Uridina Difosfato Glucose Desidrogenase/genética , Uridina Difosfato Glucose Desidrogenase/metabolismo , Uridina Difosfato Ácido Glucurônico/metabolismo
5.
Appl Nurs Res ; 77: 151799, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38796253

RESUMO

BACKGROUND: To achieve suitable diabetes care, understanding the factors that affect self-care behaviors is necessary. OBJECTIVE: To construct a model of dispositional mindfulness, internal environmental factors, external environmental factors, and self-care behaviors in people with diabetes. DESIGN AND METHODS: This cross-sectional study analyzed a convenience sample of 311 people with type 2 diabetes in Taiwan. Data were collected through questionnaires, including the Diabetes Symptoms Checklist, Emotional Distress Scale, Empowerment Process Scale, Interpersonal Communication Scale and Self-Care Behavior scale. RESULTS: Structural equation modeling indicated that a model of dispositional mindfulness, internal environmental factors, external environmental factors, and self-care behaviors in the patients with diabetes best fit the data. Dispositional mindfulness (ß = 0.39), internal environmental factors (ß = 0.52), and external environmental factors (ß = 0.71) directly influenced self-care behaviors in the patients with diabetes. Dispositional mindfulness significantly indirectly affected self-care behaviors via internal and external environmental factors. CONCLUSIONS: To improve self-care behaviors, interventions should consider mindfulness training, and also include internal environmental factors and external environmental factors in the mindfulness training.


Assuntos
Diabetes Mellitus Tipo 2 , Atenção Plena , Autocuidado , Humanos , Diabetes Mellitus Tipo 2/psicologia , Diabetes Mellitus Tipo 2/terapia , Masculino , Feminino , Autocuidado/psicologia , Pessoa de Meia-Idade , Atenção Plena/métodos , Estudos Transversais , Taiwan , Idoso , Adulto , Inquéritos e Questionários , Análise de Classes Latentes
6.
Inorg Chem ; 62(20): 7753-7763, 2023 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-37154416

RESUMO

To elucidate the luminescence mechanism of highly efficient blue Cu(N^N)(POP)+-type thermally activated delayed fluorescence (TADF) materials, we have selected Cu(pytfmpz)(POP)+ (1) and Cu(pympz)(POP)+ (2) as targets to investigate the photophysical properties in both solution and solid phases. The self-consistent electrostatic potential (ESP) embedded charge within the quantum mechanics/molecular mechanics (QM/MM) method demonstrates a greater advantage over the charge equilibrium (QEQ) in accurately calculating atomic charges and reasonably describing the polarization effect, ultimately resulting in a favorable consistency between simulation and experimental measurements. After systematic and quantitative simulation, it has been found that complex 2, with an electron-donating group of -CH3, exhibits a much more blue-shifted spectrum and a significantly enhanced efficiency in comparison to complex 1 with -CF3. This is due to the widened HOMO-LUMO gap as well as the narrowed energy gap between the lowest singlet and triplet excited states (ΔEST), respectively. Then, the designed complex 3 is introduced with a stronger electron donor and larger tert-butyl group, which plays a key role in simultaneously suppressing the structural distortion and reducing the ΔEST. This leads to a faster reverse intersystem crossing process than that of the two experimental complexes in solution, turning out to be a new deep-blue-emitting material with excellent TADF performance.

7.
Phys Chem Chem Phys ; 25(12): 8714-8724, 2023 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-36896759

RESUMO

Uridine diphosphate glucose (UDP-Glc) is able to accelerate the decay of snail family transcriptional repressor 1 (SNAI1) mRNA by inhibiting Hu antigen R (HuR, an RNA-binding protein), thereby preventing cancer invasiveness and drug resistance. Nevertheless, the phosphorylation of tyrosine 473 (Y473) of UDP-glucose dehydrogenase (UGDH is capable of converting UDP-Glc to uridine diphosphate glucuronic acid (UDP-GlcUA)) weakens the inhibition of UDP-Glc to HuR, thus initiating the epithelial-mesenchymal transformation of tumor cells and promoting tumor cell migration and metastasis. To address the mechanism, we performed molecular dynamics simulations combined with molecular mechanics generalized Born surface area (MM/GBSA) analysis on wild-type and Y473 phosphorylated UGDH and HuR, UDP-Glc, UDP-GlcUA complexes. We demonstrated that Y473 phosphorylation was able to enhance the binding between UGDH and the HuR/UDP-Glc complex. Compared with HuR, UGDH has a stronger binding ability with UDP-Glc; therefore, UDP-Glc was inclined to bind to UGDH and then was catalyzed to UDP-GlcUA by UGDH, which relieved the inhibition of UDP-Glc to HuR. In addition, the binding ability of HuR for UDP-GlcUA was lower than its affinity for UDP-Glc, significantly reducing the inhibition of HuR. Hence, HuR bound to SNAI1 mRNA more easily to increase the stability of mRNA. Our results revealed the micromolecular mechanism of Y473 phosphorylation of UGDH regulating the interaction between UGDH and HuR as well as relieving the inhibition of UDP-Glc on HuR, which contributed to understanding the role of UGDH and HuR in tumor metastasis and developing small molecule drugs targeting the interaction between UGDH and HuR.


Assuntos
Uridina Difosfato Glucose , Uridina Difosfato Ácido Glucurônico , Uridina Difosfato Glucose/metabolismo , Fosforilação , Uridina Difosfato Ácido Glucurônico/metabolismo , Glucose , RNA Mensageiro
8.
Nucleic Acids Res ; 49(22): 13135-13149, 2021 12 16.
Artigo em Inglês | MEDLINE | ID: mdl-34871438

RESUMO

Homologous recombination (HR) is a primary DNA double-strand breaks (DSBs) repair mechanism. The recombinases Rad51 and Dmc1 are highly conserved in the RecA family; Rad51 is mainly responsible for DNA repair in somatic cells during mitosis while Dmc1 only works during meiosis in germ cells. This spatiotemporal difference is probably due to their distinctive mismatch tolerance during HR: Rad51 does not permit HR in the presence of mismatches, whereas Dmc1 can tolerate certain mismatches. Here, the cryo-EM structures of Rad51-DNA and Dmc1-DNA complexes revealed that the major conformational differences between these two proteins are located in their Loop2 regions, which contain invading single-stranded DNA (ssDNA) binding residues and double-stranded DNA (dsDNA) complementary strand binding residues, stabilizing ssDNA and dsDNA in presynaptic and postsynaptic complexes, respectively. By combining molecular dynamic simulation and single-molecule FRET assays, we identified that V273 and D274 in the Loop2 region of human RAD51 (hRAD51), corresponding to P274 and G275 of human DMC1 (hDMC1), are the key residues regulating mismatch tolerance during strand exchange in HR. This HR accuracy control mechanism provides mechanistic insights into the specific roles of Rad51 and Dmc1 in DNA double-strand break repair and may shed light on the regulatory mechanism of genetic recombination in mitosis and meiosis.


Assuntos
Proteínas de Ciclo Celular/metabolismo , Reparo do DNA , Proteínas de Ligação a DNA/metabolismo , Recombinação Homóloga , Complexos Multiproteicos/metabolismo , Rad51 Recombinase/metabolismo , Sequência de Aminoácidos , Proteínas de Ciclo Celular/química , Proteínas de Ciclo Celular/genética , Microscopia Crioeletrônica , DNA/química , DNA/genética , DNA/metabolismo , Quebras de DNA de Cadeia Dupla , Proteínas de Ligação a DNA/química , Proteínas de Ligação a DNA/genética , Humanos , Simulação de Dinâmica Molecular , Complexos Multiproteicos/química , Complexos Multiproteicos/ultraestrutura , Conformação de Ácido Nucleico , Conformação Proteica , Rad51 Recombinase/química , Rad51 Recombinase/genética , Homologia de Sequência de Aminoácidos
9.
Angew Chem Int Ed Engl ; 62(24): e202212860, 2023 06 12.
Artigo em Inglês | MEDLINE | ID: mdl-36998115

RESUMO

Chemical cross-linking mass spectrometry (CXMS) has emerged as a powerful technology to analyze protein complexes. However, the progress of in vivo CXMS studies has been limited by cross-linking biocompatibility and data analysis. Herein, a glycosidic bond-based MS-cleavable cross-linker of trehalose disuccinimidyl ester (TDS) was designed and synthesized, which was fragmented in MS under CID/HCD to simplify the cross-linked peptides into conventional single peptides via selective cleavage between glycosidic and peptide bonds under individual MS collision energy. Consequently, the cross-linking identification accuracy and throughput were significantly enhanced, and the popular MS mode of stepped HCD was allowed. In addition, TDS showed proper cell-penetrating properties while being highly water-soluble, making it non-DMSO dependent during solubilization. Collectively, TDS provides a promising toolkit for CXMS characterization of living systems with high biocompatibility and accuracy.


Assuntos
Glicosídeos , Espectrometria de Massas em Tandem , Espectrometria de Massas em Tandem/métodos , Peptídeos/química , Reagentes de Ligações Cruzadas/química
10.
Mol Cell Proteomics ; 19(10): 1724-1737, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32675193

RESUMO

In-depth coverage of proteomic analysis could enhance our understanding to the mechanism of the protein functions. Unfortunately, many highly hydrophobic proteins and low-abundance proteins, which play critical roles in signaling networks, are easily lost during sample preparation, mainly attributed to the fact that very few extractants can simultaneously satisfy the requirements on strong solubilizing ability to membrane proteins and good enzyme compatibility. Thus, it is urgent to screen out ideal extractant from the huge compound libraries in a fast and effective way. Herein, by investigating the interior mechanism of extractants on the membrane proteins solubilization and trypsin compatibility, a molecular dynamics simulation system was established as complement to the experimental procedure to narrow down the scope of candidates for proteomics analysis. The simulation data shows that the van der Waals interaction between cation group of ionic liquid and membrane protein is the dominant factor in determining protein solubilization. In combination with the experimental data, 1-dodecyl-3-methylimidazolium chloride (C12Im-Cl) is on the shortlist for the suitable candidates from comprehensive aspects. Inspired by the advantages of C12Im-Cl, an ionic liquid-based filter-aided sample preparation (i-FASP) method was developed. Using this strategy, over 3,300 proteins were confidently identified from 103 HeLa cells (∼100 ng proteins) in a single run, an improvement of 53% over the conventional FASP method. Then the i-FASP method was further successfully applied to the label-free relative quantitation of human liver cancer and para-carcinoma tissues with obviously improved accuracy, reproducibility and coverage than the commonly used urea-based FASP method. The above results demonstrated that the i-FASP method could be performed as a versatile tool for the in-depth coverage proteomic analysis of biological samples.


Assuntos
Líquidos Iônicos/química , Simulação de Dinâmica Molecular , Proteoma/metabolismo , Proteômica , Bacteriorodopsinas/química , Bacteriorodopsinas/metabolismo , Carcinoma Hepatocelular/metabolismo , Células HeLa , Humanos , Neoplasias Hepáticas/metabolismo , Proteínas de Membrana/metabolismo , Solubilidade , Tripsina/metabolismo
11.
Geriatr Nurs ; 48: 303-314, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36347114

RESUMO

This study sampled 86 community-dwelling older adults to investigate the effect of horticultural activities on their quality of life, perceived stress, and working memory. The results demonstrated that after 8 weeks of horticultural activities, the effect sizes (Cohen's d) of their quality of life, perceived stress, and working memory were 0.92, -1.32, and 0.62, respectively. Among the four domains of quality of life, the social relationships domain improved the most. For perceived stress, the score of the experimental group decreased from 1.70 (0.48) to 1.29 (0.58). For working memory, the score increased from 3.43 (1.13) to 4.14 (1.27), whereas the score of the control group did not change substantially. Statistical analysis conducted using a generalized estimating equation revealed a significant interaction effect between group and time (P < 0.001). This study provides a reference for improving the quality of life, perceived stress, and working memory in older people.


Assuntos
Vida Independente , Qualidade de Vida , Humanos , Idoso , Memória de Curto Prazo , Relações Interpessoais , Estresse Psicológico
12.
PLoS Biol ; 16(11): e2006525, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30427828

RESUMO

Protein transmembrane domains (TMDs) are generally hydrophobic, but our bioinformatics analysis shows that many TMDs contain basic residues at terminal regions. Physiological functions of these membrane-snorkeling basic residues are largely unclear. Here, we show that a membrane-snorkeling Lys residue in integrin αLß2 (also known as lymphocyte function-associated antigen 1 [LFA-1]) regulates transmembrane heterodimer formation and integrin adhesion through ionic interplay with acidic phospholipids and calcium ions (Ca2+) in T cells. The amino group of the conserved Lys ionically interacts with the phosphate group of acidic phospholipids to stabilize αLß2 transmembrane association, thus keeping the integrin at low-affinity conformation. Intracellular Ca2+ uses its charge to directly disrupt this ionic interaction, leading to the transmembrane separation and the subsequent extracellular domain extension to increase adhesion activity. This Ca2+-mediated regulation is independent on the canonical Ca2+ signaling or integrin inside-out signaling. Our work therefore showcases the importance of intramembrane ionic protein-lipid interaction and provides a new mechanism of integrin activation.


Assuntos
Integrinas/fisiologia , Antígeno-1 Associado à Função Linfocitária/fisiologia , Proteínas de Membrana/fisiologia , Sequência de Aminoácidos , Cálcio/metabolismo , Adesão Celular , Citoplasma/metabolismo , Humanos , Integrinas/metabolismo , Íons , Metabolismo dos Lipídeos/fisiologia , Lipídeos/fisiologia , Antígeno-1 Associado à Função Linfocitária/metabolismo , Proteínas de Membrana/metabolismo , Concentração Osmolar , Ligação Proteica , Conformação Proteica , Domínios Proteicos/fisiologia , Transdução de Sinais , Linfócitos T/metabolismo
13.
J Chem Inf Model ; 60(6): 2939-2950, 2020 06 22.
Artigo em Inglês | MEDLINE | ID: mdl-32383873

RESUMO

Molecular docking plays an indispensable role in predicting the receptor-ligand interactions in which the protein receptor is usually kept rigid, whereas the ligand is treated as being flexible. Because of the inherent flexibility of proteins, the binding pocket of apo receptors might undergo significant conformational rearrangement upon ligand binding, which limits the prediction accuracy of docking. Here, we present an iterative anisotropic network model (iterANM)-based ensemble docking approach, which generates multiple holo-like receptor structures starting from the apo receptor and incorporates protein flexibility into docking. In a validation data set consisting of 233 chemically diverse cyclin-dependent kinase 2 (CDK2) inhibitors, the iterANM-based ensemble docking achieves higher capacity to reproduce native-like binding poses compared with those using single apo receptor conformation or conformational ensemble from molecular dynamics simulations. The prediction success rate within the top5-ranked binding poses produced by the iterANM can further be improved through reranking with the molecular mechanics-Poisson-Boltzmann surface area method. In a smaller data set with 58 CDK2 inhibitors, the iterANM-based ensemble shows a higher success rate compared with the flexible receptor-based docking procedure AutoDockFR and other receptor conformation generation approaches. Further, an additional docking test consisting of 10 diverse receptor-ligand combinations shows that the iterANM is robustly applicable for different receptor structures. These results suggest the iterANM-based ensemble docking as an accurate, efficient, and practical framework to predict the binding mode of a ligand for receptors with flexibility.


Assuntos
Proteínas , Sítios de Ligação , Ligantes , Simulação de Acoplamento Molecular , Ligação Proteica , Conformação Proteica
14.
Aging Clin Exp Res ; 32(5): 877-883, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31267378

RESUMO

BACKGROUND: Little is known about muscle strength and physical performance in Chinese. AIM: This study aimed to assess the age- and sex-related differences in muscle strength and physical performance in older Chinese. METHODS: Three hundred and eight healthy participants (110 males and 198 females) age 68.3 ± 6.1 (mean ± SD) years were enrolled in this cross-sectional study. The handgrip muscle strength (HGS) of the dominant hand was measured using a Jamar dynamometer. Physical performance was assessed by the Timed Up and Go test (TUG). The EuroQol five-dimension questionnaire (EQ-5D) was used to evaluate participants' health status. RESULTS: Men showed higher levels of HGS with a smaller percentage having low muscle strength compared with women. No differences were observed in TUG between sexes. No significant association of TUG and age was observed in males. However, older females had increased TUG and hence poorer performance. Good health status was associated with better physical performance but was not related to muscle strength in either sex. DISCUSSION: In men, there was no correlation between age and TUG, although a negative association with handgrip muscle strength was observed. For women, both muscle strength and physical performance declined with age. The sex-related differences in aging effects on physical performance in our study could partly explain why women have a higher incidence of hip fracture than men. CONCLUSION: Chinese women may be more vulnerable to severe sarcopenia in old age than men.


Assuntos
Envelhecimento/fisiologia , Força Muscular/fisiologia , Desempenho Físico Funcional , Idoso , Povo Asiático , Estudos Transversais , Feminino , Nível de Saúde , Humanos , Masculino , Pessoa de Meia-Idade , Equilíbrio Postural , Caracteres Sexuais , Estudos de Tempo e Movimento
15.
Geriatr Nurs ; 40(4): 386-391, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30792050

RESUMO

Promoting psychological health in older populations is important. This study evaluated a horticultural activity program for reducing depression and loneliness in older residents of nursing homes in Taiwan. A convenience sample of 150 older residents of three nursing homes were recruited and randomly assigned to either an experimental group or a control group. The experimental group (n = 75) participated in an 8-week horticultural activity program. The control group (n = 75) received routine care. Generalized estimating equations analyses revealed significant time by treatment interaction effects for depression (p < .001) and loneliness (p < .001). This study provides a reference for improving psychological health in older people.


Assuntos
Depressão/prevenção & controle , Depressão/terapia , Horticultura Terapêutica , Solidão/psicologia , Casas de Saúde , Idoso , Depressão/psicologia , Feminino , Humanos , Pacientes Internados/psicologia , Masculino , Qualidade de Vida , Inquéritos e Questionários , Taiwan
16.
Biomacromolecules ; 18(12): 4349-4356, 2017 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-29148735

RESUMO

Vitamin E (α-tocopherol; TPGS) micelle is a robust nanocarrier in delivering hydrophobic active pharmaceutical ingredients, but it is suffering from poor stability that is essential in terms of pharmaceutical and biomedical applications. Taking advantage of the chirality of vitamin E, this work reports the stereoselective stabilization of polymer-vitamin E conjugate micelles. Vitamin E was covalently linked to multivalent methoxy poly(ethylene glycol)-co-poly(glutamic acid), generating amphiphilic conjugates that could self-assemble into micelles. Eight types of micelles were produced via tailored combination of polymer backbone and side chain with different chirality. The particle size and critical micelle concentration analysis demonstrated a correlation between conjugate chirality and micelle stability. The most stable micelles were obtained when poly(glutamic acid) and vitamin E both are dextrorotatory, because of the high degree of α-helix revealed by both circular dichroism spectroscopy and molecular dynamics simulation. This phenomenon was further verified by the fluorescence resonance energy transfer (FRET) analysis in HepG2 cells. The current work not only provides a method to enhance the stability of vitamin E micelles, but also adds an additional facile tool in regulating the stability of polymer conjugate micelles without changing the conjugate composition.


Assuntos
Polímeros/química , Vitamina E/química , Linhagem Celular , Portadores de Fármacos/química , Sistemas de Liberação de Medicamentos/métodos , Glutamatos/química , Células Hep G2 , Humanos , Concentração de Íons de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Micelas , Tamanho da Partícula , Polietilenoglicóis/química
17.
Molecules ; 23(1)2017 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-29301229

RESUMO

In all of the classical force fields, electrostatic interaction is simply treated and explicit electronic polarizability is neglected. The condensed-phase polarization, relative to the gas-phase charge distributions, is commonly accounted for in an average way by increasing the atomic charges, which remain fixed throughout simulations. Based on the lipid polarizable force field DMPC and following the same framework as Atomic Multipole Optimized Energetics for BiomoleculAr (AMOEBA) simulation, the present effort expands the force field to new anionic lipid models, in which the new lipids contain DMPG and POPS. The parameters are compatible with the AMOEBA force field, which includes water, ions, proteins, etc. The charge distribution of each atom is represented by the permanent atomic monopole, dipole and quadrupole moments, which are derived from the ab initio gas phase calculations. Many-body polarization including the inter- and intramolecular polarization is modeled in a consistent manner with distributed atomic polarizabilities. Molecular dynamics simulations of the two aqueous DMPG and POPS membrane bilayer systems, consisting of 72 lipids with water molecules, were then carried out to validate the force field parameters. Membrane width, area per lipid, volume per lipid, deuterium order parameters, electron density profile, electrostatic potential difference between the center of the bilayer and water are all calculated, and compared with limited experimental data.


Assuntos
Lipídeos/química , Simulação de Dinâmica Molecular , Gases/química , Bicamadas Lipídicas/química , Fenômenos Físicos , Eletricidade Estática , Termodinâmica , Água/química
18.
J Comput Chem ; 37(6): 614-22, 2016 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-26493154

RESUMO

The free energy calculation library PLUMED has been incorporated into the OpenMM simulation toolkit, with the purpose to perform enhanced sampling MD simulations using the AMOEBA polarizable force field on GPU platform. Two examples, (I) the free energy profile of water pair separation (II) alanine dipeptide dihedral angle free energy surface in explicit solvent, are provided here to demonstrate the accuracy and efficiency of our implementation. The converged free energy profiles could be obtained within an affordable MD simulation time when the AMOEBA polarizable force field is employed. Moreover, the free energy surfaces estimated using the AMOEBA polarizable force field are in agreement with those calculated from experimental data and ab initio methods. Hence, the implementation in this work is reliable and would be utilized to study more complicated biological phenomena in both an accurate and efficient way. © 2015 Wiley Periodicals, Inc.


Assuntos
Dipeptídeos/química , Termodinâmica , Modelos Químicos , Simulação de Dinâmica Molecular , Água/química
19.
Proteomics ; 15(1): 68-76, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25354842

RESUMO

Many protein kinases are activated through phosphorylation of an activation loop thereby turning on downstream signaling pathways. Activation of JAK2, a nonreceptor tyrosine kinase with an important role in growth factor and cytokine signaling, requires phosphorylation of the 1007 and 1008 tyrosyl residues. Dephosphorylation of these two sites by phosphatases presumably inactivates the enzyme, but the underlying mechanism is not known. In this study, we employed MALDI-TOF/TOF and triple quadrupole mass spectrometers to analyze qualitatively and quantitatively the dephosphorylation process by using synthetic peptides derived from the tandem autophosphorylation sites (Y1007 and Y1008) of human JAK2. We found that tyrosine phosphatases catalyzed the dephosphorylation reaction sequentially, but different enzymes exhibited different selectivity. Protein tyrosine phosphatase 1B caused rapid dephosphorylation of Y1008 followed by Y1007, while SHP1 and SHP2 selectively dephosphorylated Y1008 only, and yet HePTP randomly removed a single phosphate from either Y1007 or Y1008, leaving behind mono-phosphorylated peptides. The specificity of dephosphorylation was further confirmed by molecular modeling. The data reveal multiple modes of JAK2 regulation by tyrosine phosphatases, reflecting a complex, and intricate interplay between protein phosphorylation and dephosphorylation.


Assuntos
Janus Quinase 2/química , Janus Quinase 2/metabolismo , Proteínas Tirosina Fosfatases/metabolismo , Sequência de Aminoácidos , Humanos , Células Jurkat , Dados de Sequência Molecular , Peptídeos/análise , Peptídeos/metabolismo , Fosforilação , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
20.
J Comput Chem ; 36(15): 1103-13, 2015 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-25788250

RESUMO

In this work, we aim at optimizing the performance of the anisotropic GBEMP model, which adopts a framework by combining a Gay-Berne (GB) anisotropic potential with an electric multipole (EMP) potential, in simulating a DMPC lipid bilayer in an implicit solvent model. First, the Gay-Berne parameters were initially obtained by fitting to atomistic profiles of van der Waals interactions between homodimers of molecular fragments while EMP parameters was directly derived from the expansion of point multipoles at predefined EMP sites. Second, the GB and EMP parameters for DMPC molecule were carefully optimized to be comparable to AMBER atomistic model in the calculations of the dipole moments of DMPC monomers adopting different conformations as well as the nonbonded interactions between two DMPC molecules adopting different conformations and separated at various distances. Finally, the GB parameters for DMPC were slightly adjusted in simulating a 72 DMPC bilayer system so that our GBEMP model would be able to reproduce a few important structural properties, namely, thickness (DHH), area per lipid ( AL) and volume per lipid ( VL). Meanwhile, the atomistic and experimental results for electron density profiles and order parameters were reproduced reasonably well by the GBEMP model, demonstrating the promising feature of GBEMP model in modeling lipid systems. Finally, we have shown that current GBEMP model is more efficient by a factor of about 25 than AMBER atomistic point charge model.


Assuntos
Dimiristoilfosfatidilcolina/química , Bicamadas Lipídicas/química , Solventes/química , Anisotropia , Físico-Química/métodos , Ligação de Hidrogênio , Modelos Químicos , Eletricidade Estática
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