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1.
Adv Mater ; : e2405475, 2024 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-38898702

RESUMO

While proteolysis-targeting chimeras (PROTACs) hold great potential for persistently reprogramming the immunosuppressive tumor microenvironment via targeted protein degradation, precisely activating them in tumor tissues and preventing uncontrolled proteolysis at off-target sites remain challenging. Herein, a light-triggered PROTAC nanoassembly (LPN) for photodynamic indoleamine 2,3-dioxygenase (IDO) proteolysis is reported. The LPN is derived from the self-assembly of prodrug conjugates, which comprise a PROTAC, cathepsin B-specific cleavable peptide linker, and photosensitizer, without any additional carrier materials. In colon tumor models, intravenously injected LPNs initially silence the activity of PROTACs and accumulate significantly in targeted tumor tissues due to an enhanced permeability and retention effect. Subsequently, the cancer biomarker cathepsin B begins to trigger the release of active PROTACs from the LPNs through enzymatic cleavage of the linkers. Upon light irradiation, tumor cells undergo immunogenic cell death induced by photodynamic therapy to promote the activation of effector T cells, while the continuous IDO degradation of PROTAC simultaneously blocks tryptophan metabolite-regulated regulatory-T-cell-mediated immunosuppression. Such LPN-mediated combinatorial photodynamic IDO proteolysis effectively inhibits tumor growth, metastasis, and recurrence. Collectively, this study presents a promising nanomedicine, designed to synergize PROTACs with other immunotherapeutic modalities, for more effective and safer cancer immunotherapy.

2.
ACS Nano ; 18(25): 16297-16311, 2024 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-38867457

RESUMO

While mesalamine, a 5-aminosalicylic acid (5-ASA), is pivotal in the management of inflammatory bowel disease (IBD) through both step-up and top-down approaches in clinical settings, its widespread utilization is limited by low bioavailability at the desired site of action due to rapid and extensive absorption in the upper gastrointestinal (GI) tract. Addressing mesalamine's pharmacokinetic challenges, here, we introduce nanoassemblies composed exclusively of a mesalamine prodrug that pairs 5-ASA with a mucoadhesive and cathepsin B-cleavable peptide. In an IBD model, orally administered nanoassemblies demonstrate enhanced accumulation and sustained retention in the GI tract due to their mucoadhesive properties and the epithelial enhanced permeability and retention (eEPR) effect. This retention enables the efficient uptake by intestinal pro-inflammatory macrophages expressing high cathepsin B, triggering a burst release of the 5-ASA. This cascade fosters the polarization toward an M2 macrophage phenotype, diminishes inflammatory responses, and simultaneously facilitates the delivery of active agents to adjacent epithelial cells. Therefore, the nanoassemblies show outstanding therapeutic efficacy in inhibiting local inflammation and contribute to suppressing systemic inflammation by restoring damaged intestinal barriers. Collectively, this study highlights the promising role of the prodrug nanoassemblies in enhancing targeted drug delivery, potentially broadening the use of mesalamine in managing IBD.


Assuntos
Doenças Inflamatórias Intestinais , Macrófagos , Mesalamina , Pró-Fármacos , Mesalamina/química , Mesalamina/farmacologia , Pró-Fármacos/química , Pró-Fármacos/farmacologia , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Doenças Inflamatórias Intestinais/tratamento farmacológico , Animais , Camundongos , Humanos , Nanopartículas/química , Mucosa Intestinal/metabolismo , Mucosa Intestinal/efeitos dos fármacos , Camundongos Endogâmicos C57BL , Anti-Inflamatórios não Esteroides/química , Anti-Inflamatórios não Esteroides/farmacologia , Anti-Inflamatórios não Esteroides/administração & dosagem
3.
Diagnostics (Basel) ; 14(8)2024 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-38667451

RESUMO

Aortic angiosarcomas are rare. Due to its rarity and metastatic presentation, it is difficult to diagnose metastatic aortic angiosarcoma. We describe the clinicopathological and radiologic features of a metastatic aortic angiosarcoma presenting as musculoskeletal metastases. A 59-year-old male patient presented with left thigh pain. Plain radiographs revealed multifocal osteolytic lesions in the left femur shaft. Abdominopelvic computed tomography showed a lobulated osteolytic lesion in the left iliac bone. Magnetic resonance images revealed multifocal soft tissue lesions in the thigh musculature. A positron emission tomography/computed tomography (PET/CT) scan demonstrated multiple foci of increased uptake in the left femur bone, pelvis, left thigh, and calf musculature. Focal increased uptake in the lower abdominal aorta was newly detected. Pelvis biopsy showed tumor cell nests of epithelioid cells. The tumor cells showed vasoformative features. Immunohistochemically, the tumor cells showed positivity for vimentin, CD31, and ERG. The pathologic diagnosis of epithelioid angiosarcoma was established. The origin of the tumor was presumed to be the aorta. This case underscores the importance of PET scans in identifying primary lesions. In terms of the histopathologic diagnosis of biopsy samples with tumor cells exhibiting epithelioid neoplastic morphology, employing appropriate ancillary techniques such as immunocytochemistry with vascular markers may assist in accurately diagnosing metastatic angiosarcoma.

4.
ACS Appl Mater Interfaces ; 16(5): 5462-5473, 2024 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-38266190

RESUMO

Most supramolecular systems were discovered by using a trial-and-error approach, leading to numerous synthetic efforts to obtain optimal supramolecular building blocks for selective guest encapsulation. Here, we report a simple coassembly strategy for preparing tamoxifen-selective supramolecular nanomaterials in an aqueous solution. The synthetic amphiphile molecule, 1,1,2,2-tetraphenylethylene (TPE), promotes large tamoxifen aggregate disassembly into smaller, discrete aggregates such as ribbon-like and micellar assemblies in coassembled solutions, enhancing the solubility and dispersion. The TPE moiety exhibits enhanced emission upon tamoxifen interaction, enabling the observation of the coassembled species in an aqueous solution for cell imaging. The tamoxifen-selective fluorescent micelles in the presence of a 1:1 molar ratio of TPE derivative with tamoxifen show enhanced tamoxifen absorption and anticancer effects against MCF-7 breast cancer cells. These supramolecular approaches, based on the coassembly of building blocks with molecular structural similarity, can provide a novel strategy for the efficient development of selective molecular carriers with enhanced biological activities.


Assuntos
Nanoestruturas , Tamoxifeno , Humanos , Tamoxifeno/farmacologia , Micelas , Células MCF-7
5.
Chem Sci ; 14(35): 9600-9607, 2023 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-37712040

RESUMO

This study presents the development of a ß-hairpin (tryptophan zipper, Trpzip)-based molecular tweezer (MT) that can control the folding and binding of α-helical peptides. When an α-helix isolated from the p53 protein was conjugated with Trpzip in an optimized macrocyclic structure, the folded ß-hairpin stabilized the helix conformation through the side chain-to-side chain stapling strategy, which notably enhanced target (hDM2) affinity of the peptide. On the other hand, the helicity and binding affinity were significantly reduced when the hairpin was unfolded by a redox stimulus. This stimulus-responsive property was translated into the effective capture and release of model multivalent biomaterials, hDM2-gold nanoparticle conjugates. Since numerous protein interactions are mediated by α-helical peptides, these results suggest that the ß-hairpin-based MT holds great potential to be utilized in various biomedical applications, such as protein interaction inhibition and cancer biomarker (e.g., circulating tumor cells and exosomes) detection.

6.
ACS Appl Mater Interfaces ; 15(25): 29767-29776, 2023 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-37337308

RESUMO

Variations in the functionalities of materials of different dimensions containing the same functional groups can be attributed to the structural stability and morphology of the materials. The morphology of peptide assemblies can influence their interactions with biological systems and ultimately modulate their bioactivity. Among reported Arg-Gly-Asp (RGD)-based supramolecular materials, two-dimensional (2-D) peptide assembly has been rarely studied. Herein, we report the fabrication of RGD-based supramolecular one-dimensional (1-D) and 2-D assemblies as peptide-based myoblast growth accelerators. The 2-D assembly was more effective in proliferating C2C12 cells than the 1-D assembly. These findings provide insights into the construction of optimal RGD-based supramolecular functional materials of different dimensions.


Assuntos
Oligopeptídeos , Peptídeos , Peptídeos/farmacologia , Peptídeos/química , Oligopeptídeos/farmacologia , Oligopeptídeos/química , Proliferação de Células
7.
J Am Chem Soc ; 145(3): 1793-1802, 2023 01 25.
Artigo em Inglês | MEDLINE | ID: mdl-36625369

RESUMO

Supramolecular assembly based on aromatic interactions can provide well-defined nanostructures with an understanding of intermolecular interactions at the molecular level. The peptide assembly via a supramolecular approach can overcome the inherent limitations of bioactive peptides, such as proteolytic degradations and rapid internalizations into the cytosol. Although extensive research has been carried out on supramolecular peptide materials with a two-dimensional (2D) structure, more needs to be reported on biological activity studies using well-defined 2D peptide materials. Physical and chemical properties of the 2D peptide assembly attributed to their large surface area and flexibility can show low cytotoxicity, enhanced molecular loading, and higher bioconjugation efficiency in biological applications. Here, we report supramolecular 2D materials based on the pyrene-grafted amphiphilic peptide, which contains a peptide sequence (Asp-Gly-Glu-Ala; DGEA) that is reported to bind to the integrin α2ß1 receptor in 2D cell membranes. The addition of octafluoronaphthalene (OFN) to the pyrene-grafted peptide could induce a well-ordered 2D assembly by face-centered arene-perfluoroarene stacking. The DGEA-peptide 2D assembly with a flat structure, structural stability against enzymatic degradations, and a larger size can enhance the proliferation and differentiation of muscle cells via continuous interactions with cell membrane receptors integrin α2ß1 showing a low intracellular uptake (15%) compared to that (62%) of the vesicular peptide assembly. These supramolecular approaches via the arene-perfluoroarene interaction provide a strategy to fabricate well-defined 2D peptide materials with an understanding of assembly at the molecular level for the next-generation peptide materials.


Assuntos
Integrina alfa2beta1 , Peptídeos , Peptídeos/química , Mioblastos , Diferenciação Celular , Proliferação de Células
8.
Adv Mater ; 34(49): e2205498, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36268986

RESUMO

Dynamic manipulation of supramolecular self-assembled structures is achieved irreversibly or under non-physiological conditions, thereby limiting their biomedical, environmental, and catalysis applicability. In this study, microgels composed of azobenzene derivatives stacked via π-cation and π-π interactions are developed that are electrostatically stabilized with Arg-Gly-Asp (RGD)-bearing anionic polymers. Lateral swelling of RGD-bearing microgels occurs via cis-azobenzene formation mediated by near-infrared-light-upconverted ultraviolet light, which disrupts intermolecular interactions on the visible-light-absorbing upconversion-nanoparticle-coated materials. Real-time imaging and molecular dynamics simulations demonstrate the deswelling of RGD-bearing microgels via visible-light-mediated trans-azobenzene formation. Near-infrared light can induce in situ swelling of RGD-bearing microgels to increase RGD availability and trigger release of loaded interleukin-4, which facilitates the adhesion structure assembly linked with pro-regenerative polarization of host macrophages. In contrast, visible light can induce deswelling of RGD-bearing microgels to decrease RGD availability that suppresses macrophage adhesion that yields pro-inflammatory polarization. These microgels exhibit high stability and non-toxicity. Versatile use of ligands and protein delivery can offer cytocompatible and photoswitchable manipulability of diverse host cells.


Assuntos
Microgéis , Macrófagos
9.
Pharmaceutics ; 14(10)2022 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-36297566

RESUMO

A prodrug is bioreversible medication that is specifically converted to the active drugs by enzymes overexpressed in the tumor microenvironment, which can considerably reduce the chemotherapy-induced side effects. However, prodrug strategies usually have low antitumor efficacy compared to free drugs by delayed drug release. This is because they need time to be activated by enzymatic cleavage and they also cannot be fully recovered to the active drugs. Therefore, highly potent anticancer drug should be considered to expect a sufficient antitumor efficacy. Herein, we propose tumor-specific monomethyl auristatin E (MMAE) prodrug nanoparticles for safe and effective chemotherapy. The cathepsin B-specific cleavable FRRG peptide and MMAE are chemically conjugated via one-step simple synthetic chemistry. The resulting FRRG-MMAE molecules form stable nanoparticles without any additional carrier materials by hydrophobic interaction-derived aggregations. The FRRG-MMAE nanoparticles efficiently accumulate within the tumor tissues owing to the enhanced permeability and retention (EPR) effect and inhibit the tubulin polymerization by releasing free MMAE in the cathepsin B-overexpressed tumor cells. In contrast, FRRG-MMAE nanoparticles maintain a non-toxic inactive state in the normal tissues owing to innately low cathepsin B expression, thereby reducing MMAE-related severe toxicity. Collectively, this study provides a promising approach for safe and effective chemotherapy via MMAE-based prodrug nanoparticles, which may open new avenues for advanced drug design for translational nanomedicine.

10.
Biomaterials ; 289: 121806, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-36156411

RESUMO

A carrier-free prodrug nanoparticle has emerged as a potential approach to cancer therapy. It plays a vital role in enhancing the tumor targeting and therapeutic efficacy of the anticancer agent at sites of intention wherein the prodrug nanoparticle is potentially activated. Herein, five derivatives of cathepsin B-cleavable prodrugs are synthesized via chemically conjugating different cathepsin B-cleavable peptides (Phe-Arg-Arg-Gly, Phe-Arg-Arg-Leu, Phe-Arg-Arg-Leu-Gly, Phe-Leu-Arg-Arg-Gly) to doxorubicin (DOX). The peptide-DOX prodrugs can spontaneously assemble into nanoparticles via their intermolecular hydrophobic and π-π stacking interactions. The resulting cathepsin B-cleavable prodrugs nanoparticles formed different nanoparticle structures according to the amphiphilicity and flexibility of different peptides and their particle stability and cellular uptake mechanism are carefully evaluated in vitro. Among five prodrug nanoparticles, the Phe-Arg-Arg-Leu-DOX (FRRL-DOX) nanoparticle was formed to a size of 167.5 ± 12.4 nm and stably maintains its nanoparticle structure in saline media for 3 days. The FRRL-DOX nanoparticle is well taken up by tumoral nuclei and effectively induces cancer cell death with minimal toxicity to normal cells. In addition, the FRRL-DOX nanoparticle shows 2.3-16.3-fold greater tumor-specific accumulation in vivo than other prodrug nanoparticles and free DOX. The therapeutic effect of FRRL-DOX is finally examined, demonstrating 2.1-fold better anticancer efficacy compared to that of free DOX. Notably, the FRRL-DOX nanoparticle does not exert serious toxicity in its repeated intravenous administration at a high dose of up to 10 mg/kg (equiv. to DOX). In conclusion, the peptide sequence for cathepsin B-cleavable prodrug nanoparticle is determined to be successfully optimized in a way of increasing its tumor selectivity and lowering toxicity to normal tissues.


Assuntos
Antineoplásicos , Nanopartículas , Neoplasias , Pró-Fármacos , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Catepsina B/metabolismo , Catepsina B/uso terapêutico , Linhagem Celular Tumoral , Doxorrubicina/farmacologia , Doxorrubicina/uso terapêutico , Humanos , Nanopartículas/química , Neoplasias/tratamento farmacológico , Peptídeos/uso terapêutico , Pró-Fármacos/química
11.
Animals (Basel) ; 12(14)2022 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-35883346

RESUMO

The aim of this study was to investigate the effects of stimbiotic (STB), a xylanase and xylo-oligosaccharide complex. A total of 36 male weaned pigs with initial body weights of 8.49 ± 0.10 kg were used in a 3-week experiment. The experiment was conducted in a 2 × 3 factorial arrangement (six replicates/treatment) of treatments consisting of two levels of challenge (challenge and non-challenge) and three levels of STB (0, 0.5, and 1 g/kg diet). Supplementations STB 0.5 g/kg (STB5) and STB 1 g/kg (STB10) improved the G:F (p = 0.04) in piglets challenged with STEC. STB supplementation, which also decreased (p < 0.05) the white blood cells, neutrophils, lymphocytes, and expression levels of tumor necrosis factor-alpha and interleukin-6. Supplementations STB5 and STB10 improved (p < 0.01) the lymphocytes and neutrophils in piglets challenged with STEC on 14 dpi. Additionally, supplementations STB5 and STB10 improved (p < 0.01) the tumor necrosis factor-alpha in piglets challenged with STEC on 3 dpi. Supplementations STB5 and STB10 also improved the villus height-to-crypt depth ratio (p < 0.01) in piglets challenged with STEC. Supplementation with STB reduced (p < 0.05) the expression levels of calprotectin. In conclusion, STB could alleviate a decrease of the performance, immune response, and inflammatory response induced by the STEC challenge.

12.
ACS Appl Mater Interfaces ; 14(14): 16100-16107, 2022 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-35377593

RESUMO

N-Acetylneuraminic acid (Neu5Ac), one of the abundant types of sialic acid, is an emerging anticancer agent owing to its ability to target selectins in the plasma membrane of cancer cells. Considering the functionality of Neu5Ac, obtaining novel Neu5Ac-conjugated materials with a selective and an enhanced antitumor activity has remained a challenge. Herein, we report the supramolecular materials of three novel amphiphiles composed of Neu5Ac as a hydrophilic segment and pyrene or adamantane as a hydrophobic segment. The synthetic amphiphiles 1, 2, and 3 self-assembled into ribbons, vesicles, and irregular aggregates in an aqueous solution, respectively. Among the materials, vesicles of amphiphile 2 showed the most substantial selectivity toward cancer cells, followed by cell death due to the production of reactive oxygen species by the pyrene group. The dual advantage of Neu5Ac-selectivity and the pyrene-cytotoxicity of vesicles of amphiphile 2 can provide a strategy for effective anticancer materials.


Assuntos
Ácido N-Acetilneuramínico , Membrana Celular/metabolismo , Interações Hidrofóbicas e Hidrofílicas , Ácido N-Acetilneuramínico/metabolismo
13.
Theranostics ; 12(5): 1999-2014, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35265195

RESUMO

Rationale: Cancer immunotherapy combining immune checkpoint blockade (ICB) with chemotherapeutic drugs has provided significant clinical advances. However, such combination therapeutic regimen has suffered from severe toxicity of both drugs and low response rate of patients. In this study, we propose anti-PD-L1 peptide-conjugated prodrug nanoparticles (PD-NPs) to overcome these obstacles of current cancer immunotherapy. Methods: The functional peptide, consisted of anti-PD-L1 peptide and cathepsin B-specific cleavable peptide, is conjugated to a doxorubicin (DOX), resulting in prodrug nanoparticles of PD-NPs via intermolecular interactions. The antitumor efficacy and immune responses with minimal side effects by PD-NPs combining PD-L1 blockade and ICD are evaluated in breast tumor models. Results: The PD-NPs are taken up by PD-L1 receptor-mediated endocytosis and then induce ICD in cancer cells by DOX release. Concurrently, PD-L1 blockade by PD-NPs disrupt the immune-suppressing pathway of cancer cells, resulting in proliferation and reinvigoration of T lymphocytes. In tumor models, PD-NPs accumulate within tumor tissues via enhanced permeability and retention (EPR) effect and induce immune-responsive tumors by recruiting a large amount of immune cells. Conclusions: Collectively, targeted tumor delivery of anti-PD-L1 peptide and DOX via PD-NPs efficiently inhibit tumor progression with minimal side effects.


Assuntos
Nanopartículas , Neoplasias , Pró-Fármacos , Antígeno B7-H1/metabolismo , Linhagem Celular Tumoral , Doxorrubicina/farmacologia , Humanos , Morte Celular Imunogênica , Imunoterapia , Nanopartículas/química , Neoplasias/tratamento farmacológico , Peptídeos , Pró-Fármacos/farmacologia
14.
Materials (Basel) ; 13(4)2020 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-32102338

RESUMO

This study investigates the effects of soft-robot geometry on magnetic guiding to develop an efficient helical mediator on a three-dimensional (3D) gastric cancer model. Four different magnetically active helical soft robots are synthesized by the inclusion of 5-µm iron particles in polydimethylsiloxane matrices. The soft robots are named based on the diameter and length (D2-L15, D5-L20, D5-L25, and D5-L35) with samples having varied helical pitch and weight values. Then, the four samples are tested on a flat surface as well as a stomach model with various 3D wrinkles. We analyze the underlying physics of intermittent magnetomotility for the helix on a flat surface. In addition, we extract representative failure cases of magnetomotility on the stomach model. The D5-L25 sample was the most suitable among the four samples for a helical soft robot that can be moved to a target lesion by the magnetic-flux density of the stomach model. The effects of diameter, length, pitch, and weight of a helical soft robot on magnetomotility are discussed in order for the robot to reach the target lesion successfully via magnetomotility.

15.
Clin Imaging ; 55: 165-173, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30904626

RESUMO

OBJECTIVE: To determine the usefulness of adding contrast-enhanced (CE) magnetic resonance imaging (MRI) to conventional MRI for evaluation of spinal metastases. MATERIALS AND METHODS: One-hundred-and-two whole spine MR examinations, obtained for metastasis work-up within a 2-month period, from 65 men and 37 women (mean age, 64 years) with extra-spinal tumor, who also underwent CE-MRI, were retrospectively evaluated by three radiologists. The number of spine segments with bone marrow involvement was interpreted using a 3-point confidence scale (probable metastasis, equivocal, probably benign) during session 1 (conventional imaging) and session 2 (addition of CE-MRI to conventional imaging). The patients were assigned to 14 categories based on the changes in confidence rating between sessions 1 and 2; these were aggregated to four groups indicating the degree of usefulness of CE-MRI: definitely useful, equivocal, not useful, and presumed non-metastatic groups. Clinical information, metastatic bone type, the number of probably metastatic segments, and anatomical level and position were compared among the former three groups. RESULTS: The readers assigned 39-53% of cases to the definitely useful group. The number of probably metastatic segments differed significantly among the three groups for all readers (p ≤ 0.046). Age, sex, primary cancer, metastatic bone type, and anatomical level and position were similar. CONCLUSION: Adding CE-MRI to conventional MRI was useful for objectively detecting and characterizing spinal segments with metastases in 39-53% of cases. However, there were no clinical or radiological factors that could predict the usefulness of CE-MRI in evaluating spinal metastases, except for the number of metastatic segments.


Assuntos
Imageamento por Ressonância Magnética/métodos , Neoplasias da Coluna Vertebral/patologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Osso e Ossos/patologia , Meios de Contraste , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Sensibilidade e Especificidade , Neoplasias da Coluna Vertebral/secundário , Coluna Vertebral/patologia , Adulto Jovem
16.
Chem Commun (Camb) ; 53(79): 10958-10961, 2017 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-28936530

RESUMO

We report peptide vesicles with chiral membranes as enantioselective nanoreactors. The peptide vesicles are able to selectively encapsulate only a single enantiomer from a racemic mixture solution through preferential diffusion across the membranes. Notably, the confined space of the vesicle acts as an enantioselective nanoreactor for the encapsulated enantiomer which undergoes further chemical transformations to yield a highly enantiopure product.


Assuntos
Membranas Artificiais , Microquímica/métodos , Nanoestruturas/química , Nanotecnologia/métodos , Peptídeos/química , Sequência de Aminoácidos , Modelos Moleculares , Nanoestruturas/ultraestrutura , Conformação Proteica em alfa-Hélice , Estereoisomerismo
17.
Nat Nanotechnol ; 12(6): 551-556, 2017 07.
Artigo em Inglês | MEDLINE | ID: mdl-28346455

RESUMO

Hierarchical assemblies of biomolecular subunits can carry out versatile tasks at the cellular level with remarkable spatial and temporal precision. As an example, the collective motion and mutual cooperation between complex protein machines mediate essential functions for life, such as replication, synthesis, degradation, repair and transport. Nucleic acid molecules are far less dynamic than proteins and need to bind to specific proteins to form hierarchical structures. The simplest example of these nucleic acid-based structures is provided by a rod-shaped tobacco mosaic virus, which consists of genetic material surrounded by coat proteins. Inspired by the complexity and hierarchical assembly of viruses, a great deal of effort has been devoted to design similarly constructed artificial viruses. However, such a wrapping approach makes nucleic acid dynamics insensitive to environmental changes. This limitation generally restricts, for example, the amplification of the conformational dynamics between the right-handed B form to the left-handed Z form of double-stranded deoxyribonucleic acid (DNA). Here we report a virus-like hierarchical assembly in which the native DNA and a synthetic coat undergo repeated collective helicity switching triggered by pH change under physiological conditions. We also show that this collective helicity inversion occurs during translocation of the DNA-coat assembly into intracellular compartments. Translating DNA conformational dynamics into a higher level of hierarchical dynamics may provide an approach to create DNA-based nanomachines.


Assuntos
Materiais Revestidos Biocompatíveis/química , Conformação de Ácido Nucleico , Compostos de Piridínio/sangue , Animais , Dicroísmo Circular , DNA , Células HeLa , Humanos , Concentração de Íons de Hidrogênio , Microscopia Eletrônica de Transmissão , Salmão
18.
J Am Chem Soc ; 138(18): 5773-6, 2016 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-27078796

RESUMO

Although significant progress has been achieved with short peptide nanostructures, the construction of switchable membrane assemblies remains a great challenge. Here we report short α-peptide assemblies that undergo thermo-reversible switching between assembly and disassembly states, triggered by the conformational change of laterally grafted short peptides from a folded α-helix to a random coil conformation. The α-helical peptide based on two oligoether dendron side groups forms flat disks, while the peptide helix based on three dendron side groups forms hollow vesicles. The vesicular membrane can spontaneously capture a racemic mixture through the self-formation of vesicular containers upon heating and enantioselectively release the chiral guest molecule through preferential diffusion across the vesicular walls.


Assuntos
Peptídeos/química , Algoritmos , Sequência de Aminoácidos , Dendrímeros , Difusão , Espectroscopia de Ressonância Magnética , Membranas Artificiais , Conformação Molecular , Nanoestruturas , Conformação Proteica em alfa-Hélice , Estrutura Secundária de Proteína , Estereoisomerismo
19.
Nat Commun ; 6: 8650, 2015 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-26456695

RESUMO

While encouraging progress has been made on switchable nanopores to mimic biological channels and pores, it remains a great challenge to realize long tubular pores with a dynamic open-closed motion. Here we report µm-long, dynamic tubular pores that undergo rapid switching between open and closed states in response to a thermal signal in water. The tubular walls consist of laterally associated primary fibrils stacked from disc-shaped molecules in which the discs readily tilt by means of thermally regulated dehydration of the oligoether chains placed on the wall surfaces. Notably, this pore switching mediates a controlled water-pumping catalytic action for the dehydrative cyclization of adenosine monophosphate to produce metabolically active cyclic adenosine monophosphate. We believe that our work may allow the creation of a variety of dynamic pore structures with complex functions arising from open-closed motion.


Assuntos
Nanoporos , Monofosfato de Adenosina , AMP Cíclico/síntese química , Temperatura Alta , Nanoporos/ultraestrutura
20.
PLoS One ; 9(2): e87030, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24523867

RESUMO

Microglial activation plays a pivotal role in the development and progression of neurodegenerative diseases. Thus, anti-inflammatory agents that control microglial activation can serve as potential therapeutic agents for neurodegenerative diseases. Here, we designed and synthesized α-galactosylceramide (α-GalCer) analogs to exert anti-inflammatory effects in activated microglia. We performed biological evaluations of 25 α-GalCer analogs and observed an interesting preliminary structure-activity relationship in their inhibitory influence on NO release and TNF-α production in LPS-stimulated BV2 microglial cells. After identification of 4d and 4e as hit compounds, we further investigated the underlying mechanism of their anti-inflammatory effects using RT-PCR analysis. We confirmed that 4d and 4e regulate the expression of iNOS, COX-2, IL-1ß, and IL-6 at the mRNA level and the expression of TNF-α at the post-transcriptional level. In addition, both 4d and 4e inhibited LPS-induced DNA binding activities of NF-κB and AP-1 and phosphorylation of p38 MAPK without affecting other MAP kinases. When we examined the anti-inflammatory effect of a p38 MAPK-specific inhibitor, SB203580, on microglial activation, we observed an identical inhibitory pattern as that of 4d and 4e, not only on NO and TNF-α production but also on the DNA binding activities of NF-κB and AP-1. Taken together, these results suggest that p38 MAPK plays an important role in the anti-inflammatory effects of 4d and 4e via the modulation of NF-κB and AP-1 activities.


Assuntos
Anti-Inflamatórios/química , Galactosilceramidas/química , Regulação Enzimológica da Expressão Gênica , Sistema de Sinalização das MAP Quinases , Microglia/metabolismo , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Animais , Linhagem Celular , Sobrevivência Celular , Células Cultivadas , Ciclo-Oxigenase 2/metabolismo , DNA/química , Imidazóis/química , Interleucina-1beta/metabolismo , Interleucina-6/metabolismo , Lipopolissacarídeos/química , Camundongos , NF-kappa B/metabolismo , Óxido Nítrico Sintase Tipo II/metabolismo , Fosforilação , Inibidores de Proteínas Quinases/química , Piridinas/química , Fator de Transcrição AP-1/metabolismo
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