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1.
Nat Immunol ; 25(1): 102-116, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38012418

RESUMO

Chimeric antigen receptor (CAR) T cell therapies have successfully treated hematological malignancies. Macrophages have also gained attention as an immunotherapy owing to their immunomodulatory capacity and ability to infiltrate solid tumors and phagocytize tumor cells. The first-generation CD3ζ-based CAR-macrophages could phagocytose tumor cells in an antigen-dependent manner. Here we engineered induced pluripotent stem cell-derived macrophages (iMACs) with toll-like receptor 4 intracellular toll/IL-1R (TIR) domain-containing CARs resulting in a markedly enhanced antitumor effect over first-generation CAR-macrophages. Moreover, the design of a tandem CD3ζ-TIR dual signaling CAR endows iMACs with both target engulfment capacity and antigen-dependent M1 polarization and M2 resistance in a nuclear factor kappa B (NF-κB)-dependent manner, as well as the capacity to modulate the tumor microenvironment. We also outline a mechanism of tumor cell elimination by CAR-induced efferocytosis against tumor cell apoptotic bodies. Taken together, we provide a second-generation CAR-iMAC with an ability for orthogonal phagocytosis and polarization and superior antitumor functions in treating solid tumors relative to first-generation CAR-macrophages.


Assuntos
Neoplasias , Receptores de Antígenos Quiméricos , Humanos , Receptores de Antígenos de Linfócitos T , Linfócitos T , Linhagem Celular Tumoral , Receptores de Antígenos Quiméricos/genética , Imunoterapia Adotiva/métodos , Macrófagos/patologia , Microambiente Tumoral
3.
Small ; 19(42): e2302739, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37322318

RESUMO

Dual-Active-Sites Single-Atom catalysts (DASs SACs) are not only the improvement of SACs but also the expansion of dual-atom catalysts. The DASs SACs contains dual active sites, one of which is a single atomic active site, and the other active site can be a single atom or other type of active site, endowing DASs SACs with excellent catalytic performance and a wide range of applications. The DASs SACs are categorized into seven types, including the neighboring mono metallic DASs SACs, bonded DASs SACs, non-bonded DASs SACs, bridged DASs SACs, asymmetric DASs SACs, metal and nonmetal combined DASs SACs and space separated DASs SACs. Based on the above classification, the general methods for the preparation of DASs SACs are comprehensively described, especially their structural characteristics are discussed in detail. Meanwhile, the in-depth assessments of DASs SACs for variety applications including electrocatalysis, thermocatalysis and photocatalysis are provided, as well as their unique catalytic mechanism are addressed. Moreover, the prospects and challenges for DASs SACs and related applications are highlighted. The authors believe the great expectations for DASs SACs, and this review will provide novel conceptual and methodological perspectives and exciting opportunities for further development and application of DASs SACs.

4.
Phys Chem Chem Phys ; 25(41): 28479-28496, 2023 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-37846774

RESUMO

The COVID-19 pandemic caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) continues to spread globally, and rapid viral evolution and the emergence of new variants pose challenges to pandemic control. During infection, the spike protein of SARS-CoV-2 interacts with the human ACE2 protein via its receptor binding domain (RBD), and it is known that engineered forms of ACE2 can compete with wild-type (WT) ACE2 for binding to inhibit infection. Here, we conducted multiple replica molecular dynamics (MRMD) simulations to study the mechanisms of the engineered ACE2 variants 3N39 and 3N94 and provide directions for optimization. Our findings reveal that engineered ACE2 is notably more efficacious in systems that show weaker binding to WT ACE2 (i.e., WT and BA.1 RBD), but also faces immune escape as the virus evolves. Moreover, by modifying residue types near the binding interface, engineered ACE2 alters the electrostatic potential distribution and reconfigures the hydrogen bonding network, which results in modified binding to the RBD. However, this structural rearrangement does not occur in all RBD variants. In addition, we identified potentially engineerable beneficial residues and potentially engineerable detrimental residues in both ACE2 and RBD. Functional conservation can thus enable the optimization of these residues and improve the binding competitiveness of engineered ACE2, which therefore provides additional immune escape prevention. Finally, we conclude that these findings have implications for understanding the mechanisms responsible for engineered ACE2 and can help us to develop engineered ACE2 proteins that show superior performance.


Assuntos
Enzima de Conversão de Angiotensina 2 , Simulação de Dinâmica Molecular , Humanos , Sítios de Ligação , Ligação Competitiva , Pandemias , SARS-CoV-2/genética , Ligação Proteica , Mutação
5.
Biochem Biophys Res Commun ; 602: 170-178, 2022 04 30.
Artigo em Inglês | MEDLINE | ID: mdl-35278890

RESUMO

DNA repair machinery is involved in estrogen-dependent transactivation. Mounting evidence suggests that mechanisms underlying estrogen-induced DNA damage are complicated. To date estrogen-induced DNA oxidation and its impact on ERα-mediated transaction remains ambiguous. Herein, we found that the process of 17ß-estradiol (E2)-induced ROS production can be approximately divided into two phases according to responding time and generation mechanisms. The intracellular Ca2+ fluctuation and ERα-dependent transcription lead to temporospatially different oxidative DNA damage. Further, we demonstrate that DNA oxidation is dispensable for estrogen-responsive gene expression. Dynamics of estrogen-induced DNA strand break generation also show two-phase pattern and topoisomerase-mediated DNA stand breaks are essential in estrogen signaling. Collectively, our findings have provided new insights into oxidative DNA damage in estrogen signaling.


Assuntos
Neoplasias da Mama , Receptor alfa de Estrogênio , Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Linhagem Celular Tumoral , DNA , Dano ao DNA , Estradiol/metabolismo , Receptor alfa de Estrogênio/metabolismo , Estrogênios/farmacologia , Feminino , Humanos , Espécies Reativas de Oxigênio/metabolismo
6.
Small ; 18(20): e2107997, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35445554

RESUMO

Direct electrochemical conversion of CO2 to CO product powered by renewable electricity is widely advocated as an emerging strategy for alleviating CO2 emissions while addressing global energy issues. However, the development of low-cost and efficient electrocatalysts with high Faradaic efficiency for CO production (FECO ) and high current density remains a grand challenge. Herein, a robust single nickel atomic site electrocatalyst, which features isolated and dense single atomic NiN3 sites anchored on highly defective hierarchically micro-mesoporous carbon (Ni-SAs/HMMNC-800), to enable enhanced charge transport and more exposed active sites for catalyzing electrochemical CO2 -to-CO conversion, is reported. The Ni-SAs/HMMNC-800 catalyst achieves excellent activity and selectivity with high FECO values of >90% throughout a wide potential range (the FECO reaches 99.5% at -0.7 V vs reversible hydrogen electrode) and a CO partial current density as high as 13.0 mA cm-2 at -0.7 V versus reversible hydrogen electrode, as well as a far outstanding durability during long-term continuous operation, indicating a superior CO2 electroreduction performance than that of other reference samples and most of previously reported carbon-based single atom electrocatalysts. Experimental and density functional theory calculations reveal that atomic NiN3 coordination sites coupled adjacent defects are favorable to significantly enhancing the formation of COOH* reaction intermediates while suppressing the competing hydrogen evolution reaction, thereby enhancing the electrocatalytic activity for CO2 -to-CO reduction. Notably, this work provides a valuable new prospect for designing and synthesizing efficient and cost-effective single atom CO2 electroreduction catalysts for practical applications.

7.
Phys Chem Chem Phys ; 24(3): 1743-1759, 2022 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-34985081

RESUMO

The outbreak caused by SARS-CoV-2 has received extensive worldwide attention. As the main protease (Mpro) in SARS-CoV-2 has no human homologues, it is feasible to reduce the possibility of targeting the host protein by accidental drugs. Thus, Mpro has been an attractive target of efficient drug design for anti-SARS-CoV-2 treatment. In this work, multiple replica molecular dynamics (MRMD) simulations, principal component analysis (PCA), free energy landscapes (FELs), and the molecular mechanics-generalized Born surface area (MM-GBSA) method were integrated together to decipher the binding mechanism of four inhibitors masitinib, O6K, FJC and GQU to Mpro. The results indicate that the binding of four inhibitors clearly affects the structural flexibility and internal dynamics of Mpro along with dihedral angle changes of key residues. The analysis of FELs unveils that the stability in the relative orientation and geometric position of inhibitors to Mpro is favorable for inhibitor binding. Residue-based free energy decomposition reveals that the inhibitor-Mpro interaction networks involving hydrogen bonding interactions and hydrophobic interactions provide significant information for the design of potent inhibitors against Mpro. The hot spot residues including H41, M49, F140, N142, G143, C145, H163, H164, M165, E166 and Q189 identified by computational alanine scanning are considered as reliable targets of clinically available inhibitors inhibiting the activities of Mpro.


Assuntos
Antivirais/química , Tratamento Farmacológico da COVID-19 , Proteases 3C de Coronavírus/antagonistas & inibidores , Prolina/análogos & derivados , Prolina/química , SARS-CoV-2/efeitos dos fármacos , Inibidores de Protease Viral/química , Antivirais/farmacologia , Desenho de Fármacos , Humanos , Simulação de Dinâmica Molecular , Análise de Componente Principal , Prolina/farmacologia , Ligação Proteica , Conformação Proteica , Relação Estrutura-Atividade , Termodinâmica , Inibidores de Protease Viral/farmacologia
8.
Phys Chem Chem Phys ; 24(36): 22129-22143, 2022 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-36082845

RESUMO

The pneumonia outbreak caused by the SARS-CoV-2 virus poses a serious threat to human health and the world economy. The development of safe and highly effective antiviral drugs is of great significance for the treatment of COVID-19. The main protease (Mpro) of SARS-CoV-2 is a key enzyme for viral replication and transcription and has no homolog in humans. Therefore, the Mpro is an ideal target for the design of drugs against COVID-19. Insights into the inhibitor-Mpro binding mechanism and conformational changes of the Mpro are essential for the design of potent drugs that target the Mpro. In this study, we analyzed the conformational changes of the Mpro that are induced by the binding of three inhibitors, YTV, YSP and YU4, using multiple replica accelerated molecular dynamics (MR-aMD) simulations, dynamic cross-correlation map (DCCM) calculations, principal component analysis (PCA), and free energy landscape (FEL) analysis. The results from DCCM calculations and PCA show that the binding of inhibitors significantly affects the kinetic behavior of the Mpro and induces a conformational rearrangement of the Mpro. The binding ability and binding mechanism of YTV, YSP and YU4 to the Mpro were investigated using the molecular mechanics Poisson-Boltzmann surface area (MM-PBSA) method. The results indicate that substitution of the tert-butanol group by methylbenzene and trifluoromethyl groups enhances the binding ability of YSP and YU4 to the Mpro compared with YTV; moreover, massive hydrophobic interactions are detected between the inhibitors and the Mpro. Meanwhile, T25, L27, H41, M49, N142, G143, C145, M165, E166 and Q189 are identified as the key residues for inhibitor-Mpro interactions using residue-based free energy decomposition calculations, which can be employed as efficient targets in the design of drugs that inhibit the activity of the Mpro.


Assuntos
COVID-19 , Simulação de Dinâmica Molecular , Antivirais/química , Antivirais/farmacologia , Proteases 3C de Coronavírus , Cisteína Endopeptidases/metabolismo , Reposicionamento de Medicamentos/métodos , Humanos , Simulação de Acoplamento Molecular , Peptídeo Hidrolases/metabolismo , Inibidores de Proteases/química , SARS-CoV-2 , Proteínas não Estruturais Virais/metabolismo , terc-Butil Álcool
9.
BMC Musculoskelet Disord ; 23(1): 344, 2022 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-35410202

RESUMO

BACKGROUND: The aim of this study was to investigate the role of Vaspin on the chondrogenic differentiation of bone mesenchymal stem cells (BMSCs), and its effect on chondrocyte survival and ECM secretion. We also assessed whether the Akt activation participates in these processes. METHODS: In vivo, immunohistochemistry was used to examine the positive rate of the protein expressions of Akt in Wistar rat articular cartilage and subchondral bone after Vaspin intraperitoneal injection for 14 days. In vitro, we isolated and expanded BMSCs from Wistar rats, and further cultured BMSCs as pellets in a chondrogenic-differentiation medium supplemented with different concentrations of Vaspin. After 21 days, the pellets were processed for cell counting kit assay. The mRNA level of Akt, SOX9 and COL2A1 in the pellets were investigated using quantitative Real-Time polymerase chain reaction, and the protein level of COMP was detected using western blot. RESULTS: During the chondrogenic differentiation of BMSCs, Vaspin promoted the chondrogenic differentiation of BMSCs and chondrocyte survival by activating the Akt pathway. These effects were significantly reduced by treatment with an Akt inhibitor. Moreover, Vaspin promoted chondrogenic differentiation of BMSCs by increasing the expression of markers in cartilage formation and extracellular matrix secretion. Furthermore, our study also found that Vaspin could increase Akt expression in cartilage cavities and subchondral bone in vivo. CONCLUSION: These findings demonstrate that Vaspin can promote the chondrogenic differentiation of BMSCs and chondrocyte survival via Akt activation. Our study provides new insights into the potential ability of Vaspin to ameliorate the chondrogenic differentiation of BMSCs and chondrocyte survival in OA.


Assuntos
Células-Tronco Mesenquimais , Osteoartrite , Animais , Condrogênese/fisiologia , Humanos , Células-Tronco Mesenquimais/metabolismo , Osteoartrite/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Ratos , Ratos Wistar
10.
Nano Lett ; 21(22): 9691-9698, 2021 Nov 24.
Artigo em Inglês | MEDLINE | ID: mdl-34748344

RESUMO

Lithium-sulfur (Li-S) batteries suffer from multiple complex and often interwoven issues, such as the low electronic conductivity of sulfur and Li2S/Li2S2, shuttle effect, and sluggish electrochemical kinetics of lithium polysulfides (LiPSs). Guided by theoretical calculations, a multifunctional catalyst of isolated single-atom nickel in an optimal Ni-N5 active moiety incorporated in hollow nitrogen-doped porous carbon (Ni-N5/HNPC) is constructed and acts as an ideal host for a sulfur cathode. The host improved electrical conductivity, enhanced physical-chemical dual restricting capability toward LiPSs, and, more importantly, boosted the redox reaction kinetics by the Ni-N5 active moiety. Therefore, the Ni-N5/HNPC/S cathode exhibits superior rate performance, long-term cycling stability, and good areal capacity at high sulfur loading. This work highlights the important role of the coordination number of active centers in single-atom catalysts and provides a strategy to design a hollow nanoarchitecture with single-atom active sites for high-performance Li-S batteries.

11.
J Sci Food Agric ; 102(11): 4522-4531, 2022 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-35137421

RESUMO

BACKGROUND: Alginate oligosaccharides (AOS), with various physiological effects, have been widely used in the food, agricultural, and pharmaceutical industries. The biological enzymatic method of preparing AOS, using alginate lyase, has more advantages compared with physical and chemical methods. Cloning and heterologously expressing alginate lyase are therefore very important. RESULTS: A novel alginate lyase, BY17PV7, from Microbulbifer sp. BY17, isolated from Gracilaria, was cloned and expressed in Escherichia coli BL21(DE3). BY17PV7 was about 27 KDa. BY17PV7 showed the greatest activity (150.42 ± 3.32 U/mg) at 43 °C and pH 8.9. It could be activated by Ca2+ , Mn2+ , Co2+ , Fe3+ , Na+ , and inhibited by Mg2+ , Zn2+ , Ba2+ , Cu2+ , sodium dodecyl sulfate (SDS), ethylene diamine tetraacetic acid (EDTA). BY17PV7 had a wide range of substrate specificity and good degradation effects for poly ß-D-mannuronate (polyM) and poly α-L-guluronate (polyG), demonstrating that it is a bifunctional alginate lyase. The kinetic parameters showed that BY17PV7 had a greater affinity for polyG. BY17PV7 released AOS with a degree of polymerization (DP) of 3-4 in an endolytic manner from sodium alginate. Alginate oligosaccharides showed strong antioxidant ability of reducing Fe3+ and scavenging radicals such as hydroxyl, 2,2-azion-bia (3-ethylbenzo-thiazoline-6-sulfonic acid diammonium salt) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH). CONCLUSION: A novel bifunctional alginate lyase, BY17PV7, was expressed and characterized in Escherichia coli BL21(DE3). The results were helpful for the analysis of the molecular mechanisms of degrading patterns in the polysaccharide lyase (PL) family. © 2022 Society of Chemical Industry.


Assuntos
Alginatos , Polissacarídeo-Liases , Alginatos/metabolismo , Proteínas de Bactérias/metabolismo , Clonagem Molecular , Escherichia coli/genética , Escherichia coli/metabolismo , Concentração de Íons de Hidrogênio , Oligossacarídeos/metabolismo , Polissacarídeo-Liases/química , Polissacarídeo-Liases/genética , Especificidade por Substrato
12.
J Chem Inf Model ; 61(4): 1954-1969, 2021 04 26.
Artigo em Inglês | MEDLINE | ID: mdl-33739090

RESUMO

Mutations yield significant effect on the structural flexibility of two switch domains, SW1 and SW2, in K-Ras, which is considered as an important target of anticancer drug design. To unveil a molecular mechanism with regard to mutation-mediated tuning on the activity of K-Ras, multiple replica Gaussian accelerated molecular dynamics (MR-GaMD) simulations followed by analysis of free energy landscapes (FELs) are performed on the GDP- and GTP-bound wild-type (WT), G12V, and D33E K-Ras. The results suggest that G12V and D33E not only evidently change the flexibility of SW1 and SW2 but also greatly affect correlated motions of SW1 and SW2 separately relative to the P-loop and SW1, which exerts a certain tuning on the activity of K-Ras. The information stemming from the analyses of FELs reveals that the conformations of SW1 and SW2 are in high disorders in the GDP- and GTP-associated WT and mutated K-Ras, possibly producing significant effect on binding of guanine nucleotide exchange factors or effectors to K-Ras. The interaction networks of GDP and GTP with K-Ras are identified and the results uncover that the instability in hydrogen-bonding interactions of SW1 with GDP and GTP is mostly responsible for conformational disorder of SW1 and SW2 as well as tunes the activity of oncogenic K-Ras.


Assuntos
Simulação de Dinâmica Molecular , Guanosina Difosfato , Guanosina Trifosfato , Ligação de Hidrogênio , Mutação
13.
Proc Natl Acad Sci U S A ; 115(50): 12692-12697, 2018 12 11.
Artigo em Inglês | MEDLINE | ID: mdl-30487213

RESUMO

Exploring efficient and cost-effective catalysts to replace precious metal catalysts, such as Pt, for electrocatalytic oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER) holds great promise for renewable energy technologies. Herein, we prepare a type of Co catalyst with single-atomic Co sites embedded in hierarchically ordered porous N-doped carbon (Co-SAS/HOPNC) through a facile dual-template cooperative pyrolysis approach. The desirable combination of highly dispersed isolated atomic Co-N4 active sites, large surface area, high porosity, and good conductivity gives rise to an excellent catalytic performance. The catalyst exhibits outstanding performance for ORR in alkaline medium with a half-wave potential (E1/2) of 0.892 V, which is 53 mV more positive than that of Pt/C, as well as a high tolerance of methanol and great stability. The catalyst also shows a remarkable catalytic performance for HER with distinctly high turnover frequencies of 0.41 and 3.8 s-1 at an overpotential of 100 and 200 mV, respectively, together with a long-term durability in acidic condition. Experiments and density functional theory (DFT) calculations reveal that the atomically isolated single Co sites and the structural advantages of the unique 3D hierarchical porous architecture synergistically contribute to the high catalytic activity.

14.
Nano Lett ; 20(8): 6206-6214, 2020 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-32697097

RESUMO

Herein, we report efficient single copper atom catalysts that consist of dense atomic Cu sites dispersed on a three-dimensional carbon matrix with highly enhanced mesoporous structures and improved active site accessibility (Cu-SA/NC(meso)). The ratio of +1 to +2 oxidation state of the Cu sites in the Cu-SA/NC(meso) catalysts can be controlled by varying the urea content in the adsorption precursor, and the activity for ORR increases with the addition of Cu1+ sites. The optimal Cu1+-SA/NC(meso)-7 catalyst with highly accessible Cu1+ sites exhibits superior ORR activity in alkaline media with a half-wave potential (E1/2) of 0.898 V vs RHE, significantly exceeding the commercial Pt/C, along with high durability and enhanced methanol tolerance. Control experiments and theoretical calculations demonstrate that the superior ORR catalytic performance of Cu1+-SA/NC(meso)-7 catalyst is attributed to the atomically dispersed Cu1+ sites in catalyzing the reaction and the advantage of the introduced mesoporous structure in enhancing the mass transport.

15.
J Pathol ; 247(2): 158-165, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30306595

RESUMO

Keratin 17 (K17) is a type I intermediate filament mainly expressed in the basal cells of epithelia. As a multifaceted cytoskeletal protein, K17 regulates a myriad of biological processes, including cell proliferation and growth, skin inflammation and hair follicle cycling. Aberrant overexpression of K17 is found in various diseases ranging from psoriasis to malignancies such as breast, cervical, oral squamous and gastric carcinomas. Moreover, genetic mutation in KRT17 is related to tissue-specific diseases, represented by steatocystoma multiplex and pachyonychia congenita. In this review, we summarize our findings concerning the regulatory mechanisms of K17 overexpression in psoriasis and compare them to the literature relating to other diseases. We discuss data that proinflammatory cytokines, including interleukin-17 (IL-17), IL-22, interferon-gamma (IFN-γ), transforming growth factor-beta (TGF-ß) and transcription factors glioma-associated oncogene homolog 1/2 (Gli1/2), Nrf2 and p53 can regulate K17 by transcriptional and translational control. Moreover, post-translational modification, including phosphorylation and ubiquitination, is involved in the regulation of K17 stability and biological functions. We therefore review the current understanding of the K17 regulatory mechanism and its pathogenic role in diseases from dermatoses to cancer. Prospects for anti-K17 therapy in diagnosis, prognosis and disease treatment are also discussed. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.


Assuntos
Transformação Celular Neoplásica/metabolismo , Queratina-17/metabolismo , Neoplasias/metabolismo , Dermatopatias/metabolismo , Animais , Transformação Celular Neoplásica/genética , Transformação Celular Neoplásica/patologia , Citocinas/genética , Citocinas/metabolismo , Regulação Neoplásica da Expressão Gênica , Humanos , Mediadores da Inflamação/metabolismo , Queratina-17/genética , Neoplasias/genética , Neoplasias/patologia , Processamento de Proteína Pós-Traducional , Transdução de Sinais , Dermatopatias/genética , Dermatopatias/patologia , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
16.
Phys Chem Chem Phys ; 22(4): 2262-2275, 2020 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-31917380

RESUMO

Recently, fatty acid binding proteins 5 and 7 (FABP5 and FABP7) have been regarded as the prospective targets for clinically treating multiple diseases related to FABPs. In this work, multiple short molecular dynamics (MSMD) simulations followed by binding free energy calculations were performed to investigate the binding selectivity of three inhibitors, namely, 65X, 8KS, and 5M8 toward FABP5 and FABP7. The RMSF analysis suggests that the structural flexibility of FABP5 is stronger than that of FABP7; moreover, the calculated molecular surface area of FABP5 is also larger than that of FABP7. Meanwhile, the results from the cross-correlation analysis show that the inhibitor bindings exert different impacts on the internal dynamics of FABP5 and FABP7. Binding free energies predicted by the molecular mechanics/generalized Born surface area (MM-GBSA) method indicate that the increase in the enthalpy changes caused by the bindings of inhibitors toward FABP7 relative to FABP5 mostly drives the binding selectivity of the inhibitors toward FABP5 versus FABP7. Hierarchical clustering analysis based on the energy contributions of separate residues and calculations of residue-based free energy decompositions were carried out by using the equilibrated MSMD trajectories. The obtained results not only recognize the hot interaction spots of inhibitors with FABP5 and FABP7, but also display that several common residues, namely, (T56, T54), (L60, F58), (E75, E73), (A76, A78), (D79, D77), (R81, R79), (R107, R109), (C120, L118), and (R129, R127) belonging to (FABP5, FABP7) induce obvious binding differences in the inhibitors toward FABP5 and FABP7. Therefore, these residues play significant roles in the binding selectivities of inhibitors toward FABP5 and FABP7.


Assuntos
Proteína 7 de Ligação a Ácidos Graxos/antagonistas & inibidores , Proteínas de Ligação a Ácido Graxo/antagonistas & inibidores , Simulação de Dinâmica Molecular , Proteínas Supressoras de Tumor/antagonistas & inibidores , Sítios de Ligação , Análise por Conglomerados , Entropia , Proteína 7 de Ligação a Ácidos Graxos/metabolismo , Proteínas de Ligação a Ácido Graxo/metabolismo , Humanos , Ligação de Hidrogênio , Ligação Proteica , Estrutura Terciária de Proteína , Proteínas Supressoras de Tumor/metabolismo
17.
J Cell Mol Med ; 23(8): 5193-5199, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31148371

RESUMO

Vitiligo is a common skin depigmenting disorder characterized by the loss of functional melanocytes. Its pathogenesis is complicated and oxidative stress plays a critical role in the development of vitiligo. Thus, antioxidant therapy is a promising therapeutic strategy to prevent or even reverse the progression of depigmentation. Ginkgo biloba extract EGb761 has been confirmed to have protective effects on neurons against oxidative stress. Notably, several clinical trials have shown that patients with stable vitiligo achieved repigmentation after taking EGb761. However, the exact mechanism underlying the protective effects of EGb761 on melanocytes against oxidative stress has not been fully elucidated. In the present study, we found that EGb761 effectively protected melanocytes against oxidative stress-induced apoptosis and alleviated the excessive accumulation of reactive oxygen species (ROS) and lipid peroxidation by enhancing the activity of antioxidative enzymes. Furthermore, the antioxidative effect of EGb761 was achieved by activating Nrf2 and its downstream antioxidative genes. In addition, interfering Nrf2 with siRNA abolished the protective effects of EGb761 on melanocytes against oxidative damage. In conclusion, our study proves that EGb761 could protect melanocytes from H2 O2 -induced oxidative stress by activating Nrf2. Therefore, EGb761 is supposed to be a potential therapeutic agent for vitiligo.


Assuntos
Ginkgo biloba/química , Fator 2 Relacionado a NF-E2/genética , Extratos Vegetais/farmacologia , Antioxidantes/farmacologia , Apoptose/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Peróxido de Hidrogênio/farmacologia , Peroxidação de Lipídeos/efeitos dos fármacos , Oxirredução/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Extratos Vegetais/química , Espécies Reativas de Oxigênio/metabolismo
18.
Sensors (Basel) ; 20(1)2019 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-31861412

RESUMO

During pulse signal collection, width information of pulse waves is essential for the diagnosis of disease. However, currently used measuring instruments can only detect the amplitude while can't acquire the width information. This paper proposed a novel wrist pulse signal acquisition system, which could realize simultaneous measurements of the width and amplitude of dynamic pulse waves under different static forces. A tailor-packaged micro-electro-mechanical system (MEMS) sensor array was employed to collect pulse signals, a conditioning circuit was designed to process the signals, and a customized algorithm was developed to compute the width. Experiments were carried out to validate the accuracy of the sensor array and system effectiveness. The results showed the system could acquire not only the amplitude of pulse wave but also the width of it. The system provided more information about pulse waves, which could help doctors make the diagnosis.

19.
Phys Chem Chem Phys ; 20(24): 16641-16649, 2018 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-29873368

RESUMO

Fluorescent base analogues are of great importance as sensitive probes to detect the dynamic structures of DNA. In this research, the structural and photophysical properties of 13-mer oligonucleotides containing 4-aminophthalimide:2,4-diaminopyrimidine (4AP:DAP) (4AP0, 4AP') were characterized using both molecular dynamics simulations and quantum mechanics methods. The results indicate that the 4AP:DAP pair is well adapted to the overall B-DNA structure with higher stability and π-stacking abilities. The structural overlap of 4AP' and 4AP0 with the neighboring adenines only lies in the 5'-direction which results in the structure distortion from native B-DNA. Furthermore, the photophysical properties of the fluorescent base monomers and the B-DNA duplex were explored in detail. A very important result is that the hydrogen bond interaction does not have more effect on the fluorescence band apart from the slight red-shifts. In particular, the identity of the neighboring bases stacked with 4AP has an important effect on the fluorescence band. How the local environment can alter the photophysical features of the nucleobases when they are incorporated into the DNA duplex is elucidated.


Assuntos
DNA/química , Corantes Fluorescentes/química , Sondas Moleculares/química , Ftalimidas/química , Pirimidinas/química , Pareamento de Bases , DNA/genética , Fluorescência , Ligação de Hidrogênio , Simulação de Dinâmica Molecular , Sondas Moleculares/genética , Teoria Quântica
20.
Int J Mol Sci ; 19(9)2018 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-30142969

RESUMO

Designing highly selective inhibitors of fatty acid binding proteins 4 and 5 (FABP4 and FABP5) is of importance for treatment of some diseases related with inflammation, metabolism, and tumor growth. In this study, molecular dynamics (MD) simulations combined with molecular mechanics generalized Born surface area (MM-GBSA) method were performed to probe binding selectivity of three inhibitors (5M7, 65X, and 65Z) to FABP4/FABP5 with Ki values of 0.022/0.50 µM, 0.011/0.086 µM, and 0.016/0.12 µM, respectively. The results not only suggest that all inhibitors associate more tightly with FABP4 than FABP5, but also prove that the main forces driving the selective bindings of inhibitors to FABP4 and FABP5 stem from the difference in the van der Waals interactions and polar interactions of inhibitors with two proteins. Meanwhile, a residue-based free energy decomposition method was applied to reveal molecular basis that inhibitors selectively interact with individual residues of two different proteins. The calculated results show that the binding difference of inhibitors to the residues (Phe16, Phe19), (Ala33, Gly36), (Phe57, Leu60), (Ala75, Ala78), (Arg126, Arg129), and (Tyr128, Tyr131) in (FABP4, FABP5) drive the selectivity of inhibitors toward FABP4 and FABP5. This study will provide great help for further design of effective drugs to protect against a series of metabolic diseases, arteriosclerosis, and inflammation.


Assuntos
Anti-Inflamatórios/química , Proteínas de Ligação a Ácido Graxo/química , Piperidinas/química , Quinolinas/química , Sequência de Aminoácidos , Anti-Inflamatórios/síntese química , Sítios de Ligação , Proteínas de Ligação a Ácido Graxo/antagonistas & inibidores , Humanos , Interações Hidrofóbicas e Hidrofílicas , Cinética , Ligantes , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Piperidinas/síntese química , Ligação Proteica , Conformação Proteica em alfa-Hélice , Conformação Proteica em Folha beta , Domínios e Motivos de Interação entre Proteínas , Quinolinas/síntese química , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Termodinâmica
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