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1.
Methods ; 2024 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-39097178

RESUMO

Many studies have demonstrated the importance of accurately identifying miRNA-disease associations (MDAs) for understanding disease mechanisms. However, the number of known MDAs is significantly fewer than the unknown pairs. Here, we propose RSANMDA, a subview attention network for predicting MDAs. We first extract miRNA and disease features from multiple similarity matrices. Next, using resampling techniques, we generate different subviews from known MDAs. Each subview undergoes multi-head graph attention to capture its features, followed by semantic attention to integrate features across subviews. Finally, combining raw and training features, we use a multilayer scoring perceptron for prediction. In the experimental section, we conducted comparative experiments with other advanced models on both HMDD v2.0 and HMDD v3.2 datasets. We also performed a series of ablation studies and parameter tuning exercises. Comprehensive experiments conclusively demonstrate the superiority of our model. Case studies on lung, breast, and esophageal cancers further validate our method's predictive capability for identifying disease-related miRNAs.

2.
Anal Biochem ; 686: 115407, 2024 03.
Artigo em Inglês | MEDLINE | ID: mdl-38030053

RESUMO

Bacterial effector proteins are secreted by a variety of protein secretion systems and play an important role in the interaction between the host and pathogenic bacteria. Therefore, it is important to find a fast and inexpensive method to discover bacterial effectors. In this study, we propose a multi-type secretion effector adaptive random forest (TSE-ARF) to adaptively identify secretion effectors across T1SE-T4SE and T6SE based only on protein sequences. First, we proposed two new feature descriptors by considering some characteristic protein information and fused them with some universal features to form a 290-dimensional feature vector with good versatility. Then, the TSE-ARF model was used to make classification predictions by parameter adaptation of different secretion effectors integrating Shuffled Frog Leaping Algorithm and random forest. The perfect performance in TSE-ARF under different data sets and settings shows its considerable generalization ability, with which more candidate effectors were screened in the whole genome. Source code is available at https://github.com/AIMOVE/TSE-ARF.


Assuntos
Algoritmos , Algoritmo Florestas Aleatórias , Software , Bactérias/metabolismo , Proteínas de Bactérias/metabolismo
3.
Soft Matter ; 2024 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-39087847

RESUMO

The self-assembled structure has a significant impact on the performance of ion conductors. We prepared a new type of electrolyte with self-assembled structures from an azobenzene-based liquid crystalline (LC) monomer and its corresponding polymer. By doping different amounts of monomers and lithium salt LiTFSI, the self-assembled nanostructure of the electrolyte was changed from lamellae to double gyroid. The ionic conductivity of the azobenzene-based electrolytes with the double gyroid structure was 1.64 × 10-4 S cm-1, higher than most PEO-based polymer electrolytes. The azobenzene-based system provides a new strategy to design solid electrolytes with self-assembled structures that may be potentially used in solid-state lithium-ion batteries.

4.
Angew Chem Int Ed Engl ; 61(14): e202200221, 2022 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-35107203

RESUMO

Strong interchain interactions of conjugated polymers usually result in poor miscibility with molecular dopants, limiting the doping efficiency because of uncontrolled phase separation. We have developed a strategy to achieve efficient charge-transport and high doping miscibility in n-doped conjugated polymers. We solve the miscibility issue through disorder side-chains containing dopants better. Systemic structural characterization reveals a farther side-chain branching point will lead to higher disorders, which provides appropriate sites to accommodate extrinsic molecular dopants without harming original chain packings and charge-transport channels. Therefore, better sustainability of solid-state microstructure is obtained, yielding a stable conductivity even when overloading massive dopants. This work highlights the importance of realizing high host-dopant miscibility in molecular doping of conjugated polymers.

5.
Langmuir ; 2021 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-34342997

RESUMO

Photo-induced alignment of the thin-film morphologies of azobenzene-containing block copolymers (BCPs) is an effective method to obtain a uniaxial pattern of nanocylinders. Although film thickness is an important factor affecting the self-assembly of BCP thin films, the influence of film thickness on the photo-induced alignment of BCP thin-film morphology has never been systematically studied. Herein, we report the thickness-dependent photo-aligned film morphologies of the BCP containing an azobenzene-based liquid crystalline polymer and a poly(ionic liquid) (PIL), with a perfect uniaxial pattern of PIL nanocylinders. For films aligned with the unpolarized light (UPL), the out-of-plane PIL nanocylinders can be obtained in the film with a thickness of only 1L0 (∼30 nm, where L0 is the layer spacing of the hexagonally packed cylinder array), which is far lower than the thickness (more than 4L0) of the thermally annealed film needed to obtain the same morphology. This change is attributed to the orientation effect of UPL on azobenzene mesogens that suppresses the excluded volume effect. For the films aligned with linearly polarized light (LPL), to take advantage of the excluded volume effect to obtain the planar orientation of azobenzene mesogens, the thickness should be controlled to be no more than 3L0 to achieve an in-plane uniaxial alignment of PIL nanocylinders. The above relationship between the morphology and thickness of photo-aligned film eliminates the obstacles encountered in preparing films with well-ordered photo-aligned morphologies.

6.
Soft Matter ; 17(47): 10696-10702, 2021 Dec 08.
Artigo em Inglês | MEDLINE | ID: mdl-34783337

RESUMO

Anisotropic colloidal particles with concave and convex structures are useful in both theoretical studies and applications. In this work, we mass-produced polystyrene (PS) colloidal particles with multiple concavities through dispersion polymerization techniques. By increasing the delayed feeding time td of the cross-linker divinylbenzene (DVB), the morphological evolution of particles can be classified into two stages, during which the formation of different concavities is consistent with either the buckling mechanism or phase separation mechanism. By varying the DVB dosage, we found that the size of the big chamber formed on the particle surfaces decreases as the DVB dosage increases. Then, using these concave particles as seeds, 2-5 µm anisotropic colloids with various shapes, including spherical, ellipsoidal, snowman and multi-protrusion, were synthesized by seeded emulsion polymerization. Moreover, our results show that both the chambers and long narrow ditches on the surface of seeds can be the active sites for monomers to gather and polymerize, but monomers in the big chamber have a priority to polymerize first when big and small concavities both exist on seeds. The results of this study could mean great potential in synthesizing a variety of anisotropic particles with well-controlled concave morphologies.

7.
Macromol Rapid Commun ; 42(11): e2100064, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33724599

RESUMO

The preparation of 3D functional isolated mesoscopic assemblies remains a challenge in the self-assembly of polymers. Here, well-defined 3D hexagonal and hexagram prisms with uniform dimensions are acquired by the crystallization of the inclusion complex composed of a crystalline molecule tris-o-phenylenedioxycyclotriphosphazene (TPP) and a block copolymer. The crystalline TPP plays an important role in the self-assembling process. The faceted morphologies of the hexagonal and hexagram prisms are infrequent in the self-assembly field of soft materials. The formation of the prisms experiences a 3D growth mechanism. The epitaxial growth, accompanied by the heterogeneous nucleation in the edges, yields the growth of inclusion crystals. This study provides a path to construct well-defined polymeric soft materials with broad utility based on numerous supramolecular complexes.


Assuntos
Polímeros , Cristalização
8.
Exp Cell Res ; 384(1): 111615, 2019 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-31499059

RESUMO

The decreased adhesion ability of melanocytes to the neighboring keratinocytes prompts melanocytes to lose from the epidermis, comprising the critical step in vitiligo pathogenesis. The repigmentation process involves the migration of melanocytes to the lesional area. This study aims to investigate the role and mechanism of microRNA (miR)-9 in the adhesion and migration of melanocytes during vitiligo repigmentation induced by UVB treatment. The HaCaT keratinocytes were used to mimic lesional condition and the PIG1 melanocytes as perilesional condition. Human lesional vitiligo specimens showed increased miR-9 and decreased adhesion molecules such as E-cadherin and ß1 integrin. Furthermore, UVB exposure upregulated IL-10, E-cadherin, and ß1 integrin, downregulated miR-9 in HaCaT cells. Moreover, the increased IL-10 by UVB exposure decreased miR-9 level by inducing miR-9 methylation via methyltransferase DNMT3A in HaCaT cells. Additionally, miR-9 targeted and inhibited E-cadherin and ß1 integrin in HaCaT cells, and suppressed migration of PIG1 cells to UVB-exposed HaCaT cells. In conclusion, miR-9 was suppressed by IL-10 and inhibited migration of PIG1 cells to HaCaT cells during UVB-mediated vitiligo repigmentation.


Assuntos
Adesão Celular/genética , Movimento Celular/genética , Melanócitos/patologia , MicroRNAs/genética , Pigmentação da Pele/genética , Vitiligo/genética , Caderinas/genética , Estudos de Casos e Controles , Linhagem Celular , Regulação para Baixo/genética , Humanos , Cadeias beta de Integrinas/genética , Interleucina-10/genética , Queratinócitos/patologia , Raios Ultravioleta
9.
J Phys Chem B ; 128(26): 6272-6282, 2024 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-38904939

RESUMO

Coiled-coil protein origami (CCPO) is a modular strategy for the de novo design of polypeptide nanostructures. It represents a type of modular design based on pairwise-interacting coiled-coil (CC) units with a single-chain protein programmed to fold into a polyhedral cage. However, the mechanisms underlying the self-assembly of the protein tetrahedron are still not fully understood. In the present study, 18 CCPO cages with three different topologies were modeled in silico. Then, molecular dynamics simulations and CC parameters were calculated to characterize the dynamic properties of protein tetrahedral cages at both the local and global levels. Furthermore, a deformed CC unit was redesigned, and the stability of the new cage was significantly improved.


Assuntos
Simulação de Dinâmica Molecular , Proteínas , Proteínas/química , Nanoestruturas/química , Conformação Proteica
10.
Front Microbiol ; 15: 1346371, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38650876

RESUMO

Background: Increasing research has implicated the possible effect of gut microbiota (GM) on the prognosis of ischemic stroke (IS). However, the precise causal relationship between GM and functional outcomes after IS remains unestablished. Methods: Data on 211 GM taxa from the MiBioGen consortium and data on prognosis of IS from the Genetics of Ischemic Stroke Functional Outcome (GISCOME) network were utilized as summary-level data of exposure and outcome. Four kinds of Mendelian randomization (MR) methods were carried out to ascertain the causal effect of GM on functional outcomes following IS. A reverse MR analysis was performed on the positive taxa identified in the forward MR analysis to determine the direction of causation. In addition, we conducted a comparative MR analysis without adjusting the baseline National Institute of Health Stroke Scale (NIHSS) of post-stroke functional outcomes to enhance confidence of the results obtained in the main analysis. Results: Four taxa were identified to be related to stroke prognosis in both main and comparative analyses. Specifically, genus Ruminococcaceae UCG005 and the Eubacterium oxidoreducens group showed significantly negative effects on stroke prognosis, while the genus Lachnospiraceae NK4A136 group and Lachnospiraceae UCG004 showed protective effects against stroke prognosis. The reverse MR analysis did not support a causal role of stroke prognosis in GM. No evidence of heterogeneity, horizontal pleiotropy, and outliers was found. Conclusion: This MR study provided evidence that genetically predicted GM had a causal link with post-stroke outcomes. Specific gut microbiota taxa associated with IS prognosis were identified, which may be helpful to clarify the pathogenesis of ischemic stroke and making treatment strategies.

11.
Exp Dermatol ; 22(11): 764-6, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24433185

RESUMO

Activation of the α-melanocyte-stimulating hormone (αMSH)/melanocortin-1 receptor (MC1R) signalling pathway exerts antagonistic actions on cutaneous inflammatory and fibrogenic responses in addition to promoting pigment production. Herein, the expression of MC1R by keloid-derived fibroblasts and keloid scar tissue was investigated using a range of techniques. MC1R mRNA expression levels in five different keloid fibroblast cell lines were significantly reduced to less than half compared with five normal fibroblast cell lines (P < 0.05). Immunohistological analysis of tissue samples indicated that MCR1 immunoreactivity in both epidermal and dermal compartments of five keloid tissue samples was dramatically decreased compared with normal skin (P < 0.05). Insufficient expression of MC1R on human dermal fibroblasts might abolish the αMSH-mediated suppression of collagen production and myofibroblast transformation elicited by the profibrotic cytokine-transforming growth factor-ß1. Restoration of reduced MC1R by dermal fibroblasts may lead to novel scar-reducing therapeutic approaches for treating this refractory fibrotic disease.


Assuntos
Colágeno/biossíntese , Fibroblastos/metabolismo , Queloide/metabolismo , Receptor Tipo 1 de Melanocortina/metabolismo , Pele/metabolismo , Regulação da Expressão Gênica , Humanos , Melanócitos/citologia , Transdução de Sinais , Fator de Crescimento Transformador beta1/metabolismo , Cicatrização , alfa-MSH/metabolismo
12.
Mech Ageing Dev ; 211: 111779, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36731753

RESUMO

Vitiligo is a chronic autoimmune disease characterized by the T helper 1 (Th1) cytokine-driven immune destruction of melanocytes (MCs). Although narrowband ultraviolet B (NBUVB) phototherapy has been proven to be an effective therapeutic option, the repigmentation response to that phototherapy varies greatly in different vitiligo patients. Here, we demonstrate that there is an increase of NBUVB-induced cellular senescence in vitiligo MCs exposed to Th1 cytokine interferon γ (IFNγ) and/or tumor necrosis factor α (TNFα) in lesional vitiligo skin from poor responders who had undergone NBUVB phototherapy. Supplementation with exogenous recombinant human stem cell factor (rhSCF) in the culture medium as well as the lentiviral vector-mediated overexpression of cKIT could prevent the MCs from the IFNγ/TNFα-accelerated cellular senescence. Mechanistic studies indicated that the reduced ratio of membrane-bound KIT (mKIT) to the soluble form of KIT (sKIT) is directly related to the cellular senescence of vitiligo MCs following exposure to IFNγ and TNFα. Furthermore, the matrix metalloprotease 9 (MMP9) inhibitor GM6001 attenuates the production of sKIT via the suppression of cKIT ectodomain shedding. Altogether, our study indicates that the presence of Th1 cytokines IFNγ and/or TNFα in the epidermal milieu might impair the repigmentation response of vitiligo patients to NBUVB phototherapy.


Assuntos
Vitiligo , Humanos , Vitiligo/radioterapia , Vitiligo/tratamento farmacológico , Fator de Necrose Tumoral alfa , Citocinas , Interferon gama , Fototerapia , Melanócitos/patologia , Resultado do Tratamento , Aceleração
13.
J Dermatol Sci ; 108(2): 98-108, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36577564

RESUMO

BACKGROUND: Few studies have addressed the impact of the psoriasis-related proinflammatory cytokines on the proliferation and melanogenesis of melanocytes (MCs) in lesional psoriatic skin. OBJECTIVE: We investigated the effects of TNFα, IL17A, and IL8 on the proliferation and melanin synthesis of MCs. METHODS: Skin specimens were biopsied from patients with psoriasis vulgaris at the active stage, or from the tail skin of Dct-LacZ mice with imiquimod (IMQ)-induced psoriasiform dermatitis. Cultured keratinocytes (KCs), MCs, and human skin explants were used in this study. The numbers of MCs were measured via ß-galactosidase staining, EdU incorporation and HMB45 immunohistochemical staining. The expression of human ß-defensin 3 (hBD3) in KCs was silenced by siRNA, the conditioned medium (CM) from siRNA-transfected KCs was used to treat MCs, then followed by αMSH stimulation. The melanogenesis-related genes were examined by using qRT-PCR and western blotting. RESULTS: The increased number of MCs and decreased melanin content were highly relevant to the enhanced expression of IL8 and BD3 both in human psoriatic skin and in IMQ-treated mouse tail skin. IL8 expression in KCs and CXCR2 expression in MCs was significantly increased by IL17A and TNFα, the αMSH-induced upregulations of microphthalmia-associated transcription factor (MITF) and tyrosinase in MCs were abrogated by the CM from hBD3-unsilenced KCs, but not from hBD3-silenced KCs. CONCLUSION: Our results suggest the roles of IL8-CXCR2 activation in promoting MC proliferation and of BD3 upregulation in reducing melanogenesis. These findings have been implicated in the underlying mechanism that active psoriasis prefers hypopigmentation despite chronic inflammation.


Assuntos
Psoríase , Fator de Necrose Tumoral alfa , Humanos , Animais , Camundongos , Fator de Necrose Tumoral alfa/metabolismo , Melaninas/metabolismo , Citocinas/metabolismo , Interleucina-8/metabolismo , Melanócitos/metabolismo , Psoríase/metabolismo , RNA Interferente Pequeno/metabolismo , Imiquimode/farmacologia , Proliferação de Células , Fator de Transcrição Associado à Microftalmia/metabolismo
14.
ACS Appl Mater Interfaces ; 13(30): 36320-36329, 2021 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-34309364

RESUMO

The zinc-ion battery (ZIB) is a novel energy storage device, an attractive alternative to the lithium-ion battery. The frequently used aqueous electrolyte suffers from many problems such as zinc dendrites and leakage, which prompts hydrogel electrolytes and solid electrolytes as good replacements. However, hydrogel electrolytes are usually unstable, owing to water volatilization. Herein, a novel solid polymer electrolyte (SPE) utilizing coordination of zinc ions is designed and then introduced into an all-solid ZIB. Benefiting from the unique coordination structure between the polymer and zinc ions, the SPE shows outstanding flexibility, high ion conductivity, and self-healing properties. In addition, the imine bonds in the polymer allow the electrolyte to degrade in acid environments, endowing its recyclability. More importantly, solid-state ZIBs based on the polymer electrolytes exhibit an impressive cycling stability (125% capacity retention after 300 cycles) and a high coulombic efficiency (94% after 300 cycles). The results demonstrate the promising potentials of the developed SPEs that can be used in all-solid ZIBs.

15.
Chem Commun (Camb) ; 58(1): 108-111, 2021 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-34875677

RESUMO

A series of tetraphenylporphyrin-based thermotropic liquid crystals containing oligo(dimethylsiloxane) were synthesized. These disc-coil hybrids form ordered nanostructures with periodic sizes on the sub-5 nm scale, including oblique columnar, lamellar, and hexagonal columnar phases. Films with sub-5 nm line patterns and homeotropically aligned columnar structures can be obtained by substrate-induced self-assembly.

16.
Histol Histopathol ; 36(9): 995-1005, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34486677

RESUMO

Long noncoding RNAs (lncRNAs) are the most recently discovered class of noncoding RNAs. LncRNAs play a crucial role in multiple disorders. However, the role and mechanism of action of lncRNAs in keloids remain unclear. Here, qRT-PCR and western blotting assays were performed to determine the expression of genes and proteins, respectively. MTT assays were carried out to measure the proliferation of keloid fibroblasts. In addition, a luciferase activity assay was conducted to investigate the relationships between LINC00937 and miR-28-5p and between miR-28-5p and MC1R. The results showed that LINC00937 and MC1R were decreased, whereas miR-28-5p was increased in keloid tissues. LINC00937 overexpression in keloid fibroblasts could repress the extracellular matrix (ECM) deposition and cell proliferation and promote MC1R expression. Moreover, high expression of miR-28-5p and low expression of LINC00937 were detected in keloid fibroblasts. We further showed that LINC00937 promoted MC1R expression by sponging miR-28-5p. Finally, our data indicated that LINC00937 inhibited the ECM deposition and proliferation of keloid fibroblasts by inhibiting miR-28-5p and facilitating MC1R expression. Overall, LINC00937 suppressed the ECM deposition and proliferation of keloid fibroblasts by acting as an miR-28-5p sponge and promoting MC1R expression. Our data suggested that LINC00937 is a potential target for keloid treatment.


Assuntos
Proliferação de Células , Matriz Extracelular/metabolismo , Fibroblastos/metabolismo , Queloide/metabolismo , MicroRNAs/metabolismo , RNA Longo não Codificante/metabolismo , Receptor Tipo 1 de Melanocortina/metabolismo , Pele/metabolismo , Adolescente , Adulto , Células Cultivadas , Matriz Extracelular/genética , Matriz Extracelular/patologia , Feminino , Fibroblastos/patologia , Humanos , Queloide/genética , Queloide/patologia , Masculino , MicroRNAs/genética , Pessoa de Meia-Idade , RNA Longo não Codificante/genética , Receptor Tipo 1 de Melanocortina/genética , Transdução de Sinais , Pele/patologia , Adulto Jovem
17.
ACS Appl Mater Interfaces ; 12(40): 45420-45428, 2020 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-32966044

RESUMO

A white-light-emitting ion gel composed of a poly[(2-(4-vinylphenyl)ethene-1,1,2-triyl)tribenzene-b-ethylene glycol-b-(2-(4-vinylphenyl)ethene-1,1,2-triyl)tribenzene] aggregation-induced emission (AIE) network and a poly([2,2':6',2″-terpyridin]-4'-yl methacrylate-co-methyl methacrylate) Eu3+-doped network was fabricated via a solution mixing process. This ion gel exhibits special multistimuli-responsive properties, and it can change its luminescent color by changing pH, temperature, or the solvent. The unique color-changing property is attributed to the different luminescent mechanisms of the AIE/Eu3+-doped polymer networks. The former is affected by changes in its aggregation state, while the latter is controlled by the dynamic metal-ligand cross-linking bonds. Furthermore, owing to the interpenetrating networks formed by the two polymers, the hybrid gel has both good mechanical strength and flexibility. It may be used in the fields of sensors, probes, and light-emitting materials.

18.
Int J Mol Med ; 45(4): 1017-1026, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31985026

RESUMO

Clinical studies have proven that ultraviolet B (UVB) based phototherapy can induce perifollicular and marginal repigmentation patterns in the skin of vitiligo patients. It is, however, difficult to conceive how melanocytes can easily exit from their tightly interconnected epidermal microenvironment to re­enter a different location in the skin to establish a new network with neighboring keratinocytes. While it is known that matrix metalloprotease 9 (MMP9) is involved in the degradation of the extracellular matrix in physiological or pathological processes, little is known about whether MMP9 affects melanocyte migration in vitiligo repigmentation. To investigate the effects of the p53­ transient receptor potential cation channel subfamily M member 1 (TRPM1)/microRNA (miR/miRNA)­211­MMP9 axis to regulate melanocyte migration following exposure to UVB, the expression profile of MMP9 in cultured human melanocytes transfected with or without the miR­211­mimic and p53­GFP lentiviral vector, respectively were determined. Quantitative polymerase chain reaction and western blotting were used to examine p53, TRPM1 and MMP9 mRNA and protein levels in UVB­exposed and unexposed cells. The capacity of melanocytes to migrate on collagen IV substrate was estimated using a Transwell migration assay. Interestingly, the upregulation of p53 and MMP9 at the mRNA and protein levels was evident in melanocytes treated with single or repeat exposures to UVB, whereas levels of TRPM1 and miR­211 were significantly suppressed in UVB­exposed melanocytes compared with the UVB­unexposed control cells. These results indicate that the p53­TRPM1/miR­211­MMP9 axis is significantly activated in melanocytes exposed to UVB. Notably, the ability of melanocyte migration was altered by the overexpression of p53 using a lentiviral vector and by the upregulation of miR­211 using an miRNA mimic. That altered migration could be neutralized by co­treatment with GM6001 (a broad­spectrum MMP inhibitor). Overall, these results show that the MMP9­mediated migration of melanocytes is regulated by a novel mechanism driven by the p53­TRPM1/miR­211­MMP9 axis. Activation of the p53­TRPM1/miR­211­MMP9 axis potentially represents an attractive therapeutic target to improve repigmentation outcomes in vitiligo patients.


Assuntos
Metaloproteinase 9 da Matriz/metabolismo , Melanócitos/metabolismo , Melanócitos/efeitos da radiação , MicroRNAs/metabolismo , Canais de Cátion TRPM/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Raios Ultravioleta , Adolescente , Adulto , Western Blotting , Movimento Celular/efeitos da radiação , Células Cultivadas , Humanos , Adulto Jovem
19.
Chem Commun (Camb) ; 56(71): 10341-10344, 2020 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-32760981

RESUMO

Sub-5 nm ordered nanostructures including lamellar, double gyroid, and columnar phases are formed by a series of oligo(dimethylsiloxane) (ODMS)-based rod-coil liquid crystals with accurate molecular weights. Films with well-oriented line patterns can be obtained by substrate-induced directed self-assembly, which may be further used as lithographic templates.

20.
Oxid Med Cell Longev ; 2019: 2084805, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31214276

RESUMO

Although vitamin C (VC, L-ascorbic acid) has been widely used as a skin lightening agent for a long time, the mechanism by which it inhibits melanogenesis remains poorly understood. It is well-documented that the intramelanocytic pH is an important factor in regulating tyrosinase function and melanosome maturation. The activity of tyrosinase, the rate-limiting enzyme required for melanin synthesis, is generally minimal in an acidic environment. Given that VC is an acidic compound, we might speculate that the intracellular acidification of melanocytes induced by VC likely reduces melanin content through the suppression of tyrosinase activity. The results of this study reveal that treatment of melanocytes with VC or its derivatives, magnesium ascorbyl phosphate (MAP) and 3-O-ethyl-L-ascorbic acid (AAE), resulted in significant decreases in the tyrosinase activity and melanin content and in the levels of intracellular reactive oxygen species (ROS), indicating that VC and its derivatives possess antimelanogenic and antioxidative activities. Western blotting analysis indicated that VC, MAP, and AAE exert their antimelanogenic activity by inhibiting the tyrosinase activity rather than by downregulating the expression of melanogenic proteins such as tyrosinase, premelanosome protein 17 (Pmel17) and microphthalmia-associated transcription factor (MITF). Further, we found that the reduced tyrosinase activity of melanocytes treated with VC or its derivatives could be reactivated following intracellular neutralization induced by ammonium chloride (NH4Cl) or concanamycin A (Con A). Finally, we examined the expression of sodium-dependent VC transporter-2 (SVCT-2) using western blotting and qPCR, which revealed that there was a significant increase in the expression of SVCT-2 in melanocytes following treatment with VC. VC-mediated intracellular acidification was neutralized by phloretin (a putative SVCT-2 inhibitor) in a dose-dependent manner. Taken together, these data show that VC and its derivatives suppress tyrosinase activity through cytoplasmic acidification that potentially results from enhanced VC transmembrane transport via the VC transporter SVCT-2.


Assuntos
Antioxidantes/metabolismo , Ácido Ascórbico/metabolismo , Citoplasma/metabolismo , Melaninas/metabolismo , Melanócitos/fisiologia , Melanossomas/metabolismo , Monofenol Mono-Oxigenase/metabolismo , Preparações Clareadoras de Pele/metabolismo , Animais , Ácido Ascórbico/análogos & derivados , Diferenciação Celular , Linhagem Celular , Citoplasma/química , Humanos , Concentração de Íons de Hidrogênio , Camundongos , Camundongos Endogâmicos C57BL , Pigmentação da Pele , Transportadores de Sódio Acoplados à Vitamina C/genética , Transportadores de Sódio Acoplados à Vitamina C/metabolismo , Regulação para Cima
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