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1.
J Control Release ; 2024 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-38971427

RESUMO

Targeted radionuclide therapy (TRT) is an effective treatment for tumors. Self-condensation strategies can enhance the retention of radionuclides in tumors and enhance the anti-tumor effect. Considering legumain is overexpressed in several types of human cancers, we have reported a 131I-labeled radiopharmaceutical ([131I]MAAN) based on the self-condensation reaction between 2-cyanobenzothiazole (CBT) and cysteine (Cys) for treatment of legumain-overexpressed tumors in vivo. However, liver enrichment limits its application. In this study, a new radiopharmaceutical [131I]IM(HE)3AAN was synthesized by introducing a hydrophilic peptide sequence His-Glu-His-Glu-His-Glu ((HE)3) into [131I]MAAN to optimize the pharmacokinetics. Upon activation by legumain under a reducing environment, hydrophilic [131I]IM(HE)3AAN could react with its precursor to form heterologous dimer ([131I]H-Dimer) that is highly hydrophobic. Cerenkov imaging reveals that [131I]IM(HE)3AAN displayed superior tumor selectivity and longer tumor retention time as compared with [131I]MAAN, with a significant reduction in liver uptake. After an 18-day treatment with [131I]IM(HE)3AAN, the tumor proliferation was obviously inhibited, while no obvious injury was observed in the normal organs during treatment. These findings suggest [131I]IM(HE)3AAN emerges as a promising candidate for treatment of legumain-overexpressed tumors.

2.
Bioconjug Chem ; 35(5): 665-673, 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38598424

RESUMO

Enhancing the accumulation and retention of small-molecule probes in tumors is an important way to achieve accurate cancer diagnosis and therapy. Enzyme-stimulated macrocyclization of small molecules possesses great potential for enhanced positron emission tomography (PET) imaging of tumors. Herein, we reported an 18F-labeled radiotracer [18F]AlF-RSM for legumain detection in vivo. The tracer was prepared by a one-step aluminum-fluoride-restrained complexing agent ([18F]AlF-RESCA) method with high radiochemical yield (RCY) (88.35 ± 3.93%) and radiochemical purity (RCP) (>95%). More notably, the tracer can be transformed into a hydrophobic macrocyclic molecule under the joint action of legumain and reductant. Simultaneously, the tracer could target legumain-positive tumors and enhance accumulation and retention in tumors, resulting in the amplification of PET imaging signals. The enhancement of radioactivity enables PET imaging of legumain activity with high specificity. We envision that, by combining this highly efficient 18F-labeled strategy with our intramolecular macrocyclization reaction, a range of radiofluorinated tracers can be designed for tumor PET imaging and early cancer diagnosis in the future.


Assuntos
Cisteína Endopeptidases , Radioisótopos de Flúor , Tomografia por Emissão de Pósitrons , Tomografia por Emissão de Pósitrons/métodos , Radioisótopos de Flúor/química , Cisteína Endopeptidases/metabolismo , Cisteína Endopeptidases/análise , Animais , Ciclização , Camundongos , Humanos , Compostos Radiofarmacêuticos/química , Linhagem Celular Tumoral , Camundongos Endogâmicos BALB C , Fluoretos/química , Camundongos Nus
3.
Molecules ; 29(6)2024 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-38542890

RESUMO

An unparalleled copper(I)-catalyzed synthesis of 1,3,4-oxadiazoles from tertiary amines in one step has been described. The one-pot reactions involving (N-isocyanimine)triphenylphosphorane, tertiary amines, and carboxylic acids resulted in the formation of 1,3,4-oxadiazoles in moderate to good yields through a consecutive oxidative Ugi/aza-Wittig reaction, enabling the direct functionalization of sp3 C-H bonds adjacent to the nitrogen atom. This method offered several notable advantages, including ligands-free, exceptional productivity and a high functional group tolerance. The preliminary biological evaluation demonstrated that compound 4f inhibited hepatoma cells efficiently, suggesting potentially broad applications of the approach for synthesis and medicinal chemistry.


Assuntos
Cobre , Compostos Organofosforados , Oxidiazóis , Cobre/química , Oxidiazóis/química , Aminas/química , Catálise , Estresse Oxidativo
4.
Mol Pharm ; 21(3): 1382-1389, 2024 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-38372213

RESUMO

Cathepsin B, a lysosomal protease, is considered as a crucial biomarker for tumor diagnosis and treatment as it is overexpressed in numerous cancers. A stimulus-responsive SF scaffold has been reported to detect the activity of a variety of tumor-associated enzymes. In this work, a small-molecule PET tracer ([68Ga]NOTA-SF-CV) was developed by combining an SF scaffold with a cathepsin B-specific recognition substrate Cit-Val. Upon activation by cathepsin B, [68Ga]NOTA-SF-CV could form the cyclization product in a reduction environment, resulting in reduced hydrophilicity. This unique property could effectively prevent exocytosis of the tracer in cathepsin B-overexpressing tumor cells, leading to prolonged retention and amplified PET imaging signal. Moreover, [68Ga]NOTA-SF-CV had great targeting specificity to cathepsin B. In vivo microPET imaging results showed that [68Ga]NOTA-SF-CV was able to effectively visualize the expression level of cathepsin B in various tumors. Hence, [68Ga]NOTA-SF-CV may be served as a potential tracer for diagnosing cathepsin B-related diseases.


Assuntos
Radioisótopos de Gálio , Neoplasias , Humanos , Radioisótopos de Gálio/química , Catepsina B , Tomografia por Emissão de Pósitrons/métodos , Neoplasias/diagnóstico por imagem , Compostos Radiofarmacêuticos/química , Linhagem Celular Tumoral
5.
Abdom Radiol (NY) ; 49(5): 1444-1455, 2024 05.
Artigo em Inglês | MEDLINE | ID: mdl-38265452

RESUMO

PURPOSE: Microvascular invasion (MVI) is a critical factor in predicting the recurrence and prognosis of hepatocellular carcinoma (HCC) after liver transplantation (LT). However, there is a lack of reliable preoperative predictors for MVI. The purpose of this study is to evaluate the potential of an 18F-FDG PET/CT-based nomogram in predicting MVI before LT for HCC. METHODS: 83 HCC patients who obtained 18F-FDG PET/CT before LT were included in this retrospective research. To determine the parameters connected to MVI and to create a nomogram for MVI prediction, respectively, Logistic and Cox regression models were applied. Analyses of the calibration curve and receiver operating characteristic (ROC) curves were used to assess the model's capability to differentiate between clinical factors and metabolic data from PET/CT images. RESULTS: Among the 83 patients analyzed, 41% were diagnosed with histologic MVI. Multivariate logistic regression analysis revealed that Child-Pugh stage, alpha-fetoprotein, number of tumors, CT Dmax, and Tumor-to-normal liver uptake ratio (TLR) were significant predictors of MVI. A nomogram was constructed using these predictors, which demonstrated strong calibration with a close agreement between predicted and actual MVI probabilities. The nomogram also showed excellent differentiation with an AUC of 0.965 (95% CI 0.925-1.000). CONCLUSION: The nomogram based on 18F-FDG PET/CT metabolic characteristics is a reliable preoperative imaging biomarker for predicting MVI in HCC patients before undergoing LT. It has demonstrated excellent efficacy and high clinical applicability.


Assuntos
Carcinoma Hepatocelular , Fluordesoxiglucose F18 , Neoplasias Hepáticas , Transplante de Fígado , Invasividade Neoplásica , Nomogramas , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Compostos Radiofarmacêuticos , Humanos , Carcinoma Hepatocelular/diagnóstico por imagem , Carcinoma Hepatocelular/patologia , Carcinoma Hepatocelular/cirurgia , Neoplasias Hepáticas/diagnóstico por imagem , Neoplasias Hepáticas/patologia , Neoplasias Hepáticas/cirurgia , Masculino , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada/métodos , Feminino , Pessoa de Meia-Idade , Estudos Retrospectivos , Compostos Radiofarmacêuticos/farmacocinética , Idoso , Adulto , Microvasos/diagnóstico por imagem , Valor Preditivo dos Testes
6.
Mol Biomed ; 4(1): 43, 2023 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-38008847

RESUMO

Mesenchymal stem cells (MSCs) have been applied in transplantation to treat intracerebral hemorrhage (ICH) but with limited efficacy. Accumulated evidence has shown that glial cell-derived neurotrophic factor (GDNF) plays a crucial part in neuronal protection and functional recovery of the brain after ICH; however, GDNF has difficulty crossing the blood-brain barrier, which limits its application. In this study, we investigated the influences of MSCs overexpressing GDNF (MSCs/GDNF) on the brain structure as well as gait of rats after ICH and explored the possible mechanisms. We found that cell transplantation could reverse the neurological dysfunction and brain damage caused by ICH to a certain extent, and MSCs/GDNF transplantation was superior to MSCs transplantation. Moreover, Transplantation of MSCs overexpressing GDNF effectively reduced the volume of bleeding foci and increased the level of glucose uptake in rats with ICH, which could be related to improving mitochondrial quality. Furthermore, GDNF produced by transplanted MSCs/GDNF further inhibited neuroinflammation, improved mitochondrial quality and function, promoted angiogenesis and the survival of neurons and oligodendrocytes, and enhanced synaptic plasticity in ICH rats when compared with simple MSC transplantation. Overall, our data indicate that GDNF overexpression heightens the curative effect of MSC implantation in treating rats following ICH.

7.
Adv Mater ; 35(49): e2308198, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37721365

RESUMO

The chemical, physical and biological effects of chiral nanomaterials have inspired general interest and demonstrated important advantages in fundamental science. Here, chiral iron oxide supraparticles (Fe3 O4 SPs) modified by chiral penicillamine (Pen) molecules with g-factor of ≈2 × 10-3 at 415 nm are fabricated, and these SPs act as high-quality magnetic resonance imaging (MRI) contrast agents. Therein, the transverse relaxation efficiency and T2 -MRI results demonstrated chiral Fe3 O4 SPs have a r2 relaxivity of 157.39 ± 2.34 mM-1 ·S-1 for D-Fe3 O4 SPs and 136.21 ± 1.26 mM-1 ·S-1 for L-Fe3 O4 SPs due to enhanced electronic transition dipole moment for D-Fe3 O4 SPs compared with L-Fe3 O4 SPs. The in vivo MRI results show that D-Fe3 O4 SPs exhibit two-fold lower contrast ratio than L-Fe3 O4 SPs, which enhances targeted enrichment in tumor tissue, such as prostate cancer, melanoma and brain glioma tumors. Notably, it is found that D-Fe3 O4 SPs have 7.7-fold higher affinity for the tumor cell surface receptor cluster-of-differentiation 47 (CD47) than L-Fe3 O4 SPs. These findings uncover that chiral Fe3 O4 SPs act as a highly effective MRI contrast agent for targeting and imaging broad tumors, thus accelerating the practical application of chiral nanomaterials and deepening the understanding of chirality in biological and non-biological environments.


Assuntos
Neoplasias Encefálicas , Glioma , Masculino , Humanos , Compostos Férricos , Meios de Contraste , Glioma/diagnóstico por imagem , Imageamento por Ressonância Magnética/métodos
8.
Sci Rep ; 13(1): 9084, 2023 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-37277549

RESUMO

The underlying surface was the important media of air-lake interaction by transferring energy. The deployment of photovoltaic arrays on the lake has formed a new underlying surface type. But the new underlying surface is different from the natural lake. The impact of fishery complementary photovoltaic (FPV) power plants on the radiation, energy flux, and driving force is unclear. Therefore, the analysis of radiation, energy flux, and driving force by comparing the difference in the two sites under various synoptic conditions. The results indicated that the radiation components are not significantly different in the two sites under diverse synoptic conditions. The downward shortwave radiation (DSR) and net radiation ([Formula: see text]) were presented with one peak on a sunny day. The daily average DSR and Rn in the two sites were 279.1 W·m-2, 209.3 W·m-2, respectively. The daily average (cloudy day and rainy day) sensible heat flux in the two sites was 39.5 W·m-2 (FPV site), 19.2 W·m-2 (REF site), respectively. The latent heat flux was 53.2 W·m-2 and 75.2 W·m-2 on counterpart. The water body generally absorbs heat from the air (daily average ∆Q was 16.6 W·m-2) in the FPV site on a sunny day. The driving force of sensible heat flux in the FPV site was governed by the temperature of the FPV panel under sunny and cloudy conditions. The latent heat flux was determined by the product between wind speed and water-atmosphere temperature difference.

9.
ACS Nano ; 17(1): 461-471, 2023 01 10.
Artigo em Inglês | MEDLINE | ID: mdl-36562644

RESUMO

Near-infrared circularly polarized light is attractive for wide-ranging applications. However, high-performance near-infrared circularly polarized light is challenging to realize. Here, we show that left-handed chiral photonic cellulose nanocrystal (CNC) films produced from ultrasonicated suspensions enable right-handed circularly polarized luminescence with a dissymmetry factor of -0.330 in the second near-infrared window (NIR-II). We present a theoretical analysis of the adverse effect of structural defects and luminescence intensity heterogeneity on the right-handed circularly polarized luminescence glum inside the bandgap and the occurrence of left-handed circularly polarized luminescence at the band edges. We demonstrate the potential of the chiral photonic CNC films with NIR-II circularly polarized light for cancer cell discrimination. The present work identifies key scientific questions in CNC-based circularly polarized luminescence materials research.


Assuntos
Nanopartículas , Neoplasias , Celulose , Raios Infravermelhos , Luminescência , Fótons , Neoplasias/diagnóstico por imagem
10.
Sci Total Environ ; 851(Pt 1): 158190, 2022 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-35995174

RESUMO

In the rhizosphere, plant root exudates (REs) serve as a bridge between plant and soil functional microorganisms, which play a key role in the redox cycle of iron (Fe). This study examined the effects of periodic flooding and cadmium (Cd) on plant REs, the rhizosphere bacterial community structure, and the formation of root Fe plaques in the typical mangrove plant Kandelia obovata, as well as the relationship between REs and Fe redox cycling bacteria. Based on two-way analysis of variance, flooding and Cd had a considerable effect on the REs of K. obovata. DOC, NH4+-N, NO3--N, dissolved inorganic phosphorus, acetic acid, and malonic acid concentrations in REs of K. obovata increased considerably with the increase of Cd concentration under 5 and 10 h flooding conditions. Fe plaque development in the plant root was stimulated by flooding and Cd, although flooding was more effective. After Cd treatment, the ways in which Fe-oxidizing bacteria (FeOB) and Fe-reducing bacteria (FeRB) were enriched in the rhizosphere and rhizoplane of plants were different. Thiobacillus and Sideroxydans (dominant FeOB) were more abundant in the plant rhizosphere, whereas Acinetobacter (dominant FeRB) was more abundant in the rhizoplane. Cd considerably decreased the relative abundance of unclassified_f_Gallionellaceae in the rhizosphere and rhizoplane but dramatically enhanced the relative abundance of Thiobacillus, Shewanella, and unclassified_f_Geobacteraceae. Unclassified_f_Geobacteraceae and Thiobacillus exhibited substantial positive correlations with citric acid and DOC in REs in the rhizosphere and rhizoplane but strong negative correlations with Sideroxydans. The findings indicate that Cd and flooding treatments may play a role in the production and breakdown of Fe plaque in K. obovata roots by affecting the relative abundance of Fe redox cycling bacteria in the rhizosphere and rhizoplane.


Assuntos
Rhizophoraceae , Poluentes do Solo , Bactérias/metabolismo , Cádmio/análise , Ácido Cítrico/metabolismo , Exsudatos e Transudatos/química , Exsudatos e Transudatos/metabolismo , Ferro/análise , Fósforo/análise , Exsudatos de Plantas/análise , Raízes de Plantas/metabolismo , Rizosfera , Plântula/metabolismo , Solo/química , Poluentes do Solo/análise
11.
Stem Cell Rev Rep ; 18(2): 570-584, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-33661471

RESUMO

BACKGROUND: Previous studies have showed the beneficial effects of mesenchymal stem cells (MSCs) on experimental intracerebral hemorrhage (ICH) animal. Enhancement of the treatment efficacy of MSCs in ICH is essential, considering the diseases association with high rates of disability and mortality. Some auxiliary methods to enhance the beneficial efficacy of MSCs have been introduced. However, the effect of electroacupuncture (EA) on the therapeutic efficacy of MSCs transplantation in hemorrhagic stroke and its potential mechanism is not explored. METHODS: ICH rat models were established using collagenase and heparin. 48 h after ICH induction, the rats were randomly divided into model control (MC), MSCs transplantation (MSCs), EA stimulation (EA) and MSCs transplantation combined with EA stimulation (MSCs + EA) groups. We used mNSS test and gait analysis to assess neurological function of rats, and PET/CT to evaluate the volume of hemorrhage focus and level of glucose uptake. The concentrations of MDA, SOD, NSE, S100B and MBP in serum or plasma were examined with ELISA. Neural differentiation of MSCs, and the expressions of Bcl-2, Bax, Arg-1 and iNOS proteins around hematoma were detected by immunofluorescence and immunohistochemistry staining respectively. Western blot was carried out to analyze the expression levels of COX4, OGDH, PDH-E1α, Bcl-2 and Bax proteins. TUNEL staining was used to estimate cell apoptosis and transmission electron microscopy (TEM) was used to observe the ultrastructure and number of mitochondria. RESULTS: Our data showed that EA promoted neuron-like differentiation of transplanted MSCs and the expressions of BDNF and NGF proteins in ICH rats. The score of mNSS and the gait analysis showed that the recovery of the neurological function in the MSCs + EA group was better than that in the MSCs and EA groups. EA improved the structure of brain tissue, and alleviated brain injury further after MSCs transplantation in ICH rats. When compared with the MSCs and EA groups, the level of glucose uptake and numbers of mitochondria and Arg-1 positive cells in MSCs + EA group increased significantly, but the numbers of apoptotic cells and iNOS positive cells and volume of hemorrhage focus reduced. The expressional levels of COX4, OGDH, PDH-E1α and Bcl-2 proteins increased, while the expressional level of Bax protein decreased compared with those in the MSCs and EA groups. CONCLUSIONS: Our results reveal that EA improve therapeutic efficacy of MSCs transplantation in ICH rats.


Assuntos
Eletroacupuntura , Células-Tronco Mesenquimais , Animais , Hemorragia Cerebral/metabolismo , Hemorragia Cerebral/terapia , Eletroacupuntura/métodos , Glucose/metabolismo , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Ratos , Ratos Sprague-Dawley , Proteína X Associada a bcl-2/metabolismo
12.
Mod Pathol ; 34(2): 291-299, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-32778677

RESUMO

The anatomic stage groups (ASG) have been arguably the most powerful in predicting breast cancer (BC) outcomes. Recognizing the prognostic influence of histologic grade and receptor status, the 8th AJCC mandates their incorporation into the newly established prognostic stage groups (PSG). This staging scheme was subsequently revised to provide pathological and clinical prognostic stage tables (PPSG/CPSG) due to its incapability to categorize a significant subset of BCs, with the former only used for patients having surgical resection as the initial treatment, and the latter for all patients. Given the increasingly used neoadjuvant therapy, PPSG cannot be assigned in a significant proportion of higher staged BCs. In this study, we validated the CPSG in a cohort of 5321 BCs. Compared to ASG, the application of CPSG resulted in assigning 16.1% and 27.2% of cases to a higher or a lower stage group in non-stage IV BCs, respectively. The changes were seen mostly frequently in ASG IB, followed by IIIC, IIB, IIA, IIIA, IIIB, and IA. In 7.9% of cases, the assigned CPSG changed more than one stage group from the ASG. CPSG provided an improved overall discriminating power in predicting BC-specific survival when compared to ASG. Pairwise comparison using the Cox proportional hazard model demonstrated further advantages for CPSG as the latter showed a significant difference in all categories when compared to their proximate groups, except IIA vs. IB and IIIA vs. IIIB. In contrast, a significantly different hazard was only seen when comparing IIB vs. IIA, IIIA vs. IIB, and IV vs. IIIC for ASG. Thus, the revised 8th AJCC CPSG provided a superior overall staging scheme for predicting prognostic outcomes in BC patients receiving standard of care treatment. Further validation using the available data with larger populations and longer follow-up may be needed to refine and improve this table.


Assuntos
Neoplasias da Mama/patologia , Estadiamento de Neoplasias/métodos , Estadiamento de Neoplasias/normas , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Pessoa de Meia-Idade , Prognóstico , Adulto Jovem
13.
J Mater Chem B ; 8(35): 7899-7903, 2020 09 21.
Artigo em Inglês | MEDLINE | ID: mdl-32845948

RESUMO

The ability to control small drug release is crucial in biomedicine, especially for inhibiting the side effects of drugs, but it is still challenging. Herein, to mimic the controlled release of drugs, the release of organic molecules, e.g., small organic dyes and peptides, through Covalent Organic Framework (COF) membranes with ordered nanoscale pores has been investigated, showing constant zero-order release behaviours. Meanwhile, biological assessments show the good biocompatibility of the COF membrane-based release system, and the high stability of the COF membrane was manifested by the long-term release of small molecules in aqueous media.


Assuntos
Portadores de Fármacos/química , Liberação Controlada de Fármacos , Compostos Organometálicos/química , Peptídeos/química , Bibliotecas de Moléculas Pequenas/química , Água/química
14.
Toxins (Basel) ; 12(1)2020 01 19.
Artigo em Inglês | MEDLINE | ID: mdl-31963878

RESUMO

Aspergillus flavus is one of the most opportunistic pathogens invading many important oilseed crops and foodstuffs with such toxic secondary metabolites as aflatoxin (AF) and Cyclopiazonic acid. We previously used the DNA methylation inhibitor 5-azacytidine to treat with an AF-producing A. flavus A133 strain, and isolated a mutant (NT) of A. flavus, which displayed impaired abilities of AF biosynthesis and fungal development. In this study, gas chromatography-mass spectrometry (GC-MS) analysis was used to reveal the metabolic changes between these two strains. A total of 1181 volatiles were identified in these two strains, among which 490 volatiles were found in these two strains in vitro and 332 volatiles were found in vivo. The NT mutant was found to produce decreasing volatile compounds, among which most of the fatty acid-derived volatiles were significantly downregulated in the NT mutant compared to the A133 strain, which are important precursors for AF biosynthesis. Two antioxidants and most of the amino acids derived volatiles were found significantly upregulated in the NT mutant. Overall, our results reveal the difference of metabolic profiles in two different A. flavus isolates, which may provide valuable information for controlling infections of this fungal pathogen.


Assuntos
Aflatoxinas/metabolismo , Aspergillus flavus , Azacitidina/toxicidade , Cromatografia Gasosa-Espectrometria de Massas , Aflatoxina B1 , Agentes de Controle Biológico , Produtos Agrícolas , Proteínas Fúngicas , Indóis , Família Multigênica
15.
iScience ; 23(1): 100803, 2020 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-31958759

RESUMO

We followed visual development in a rare yet large sample of patients with congenital bilateral cataract for 4 years. We divided the patients into two groups: a complete deprivation group with no response to a flashlight pointing to either of their eyes and otherwise an incomplete deprivation group. All the patients received cataract surgery at age of 3 months. From 27 months onward, the complete deprivation group showed better developmental outcomes in acuity and eyeball growth than the incomplete deprivation group. Such a seemingly counterintuitive finding is consistent with research on visually deprived animals. Plasticity is better preserved in animals receiving a short period of complete visual deprivation from birth than in animals who saw diffuse light. The current finding that plasticity in visual development is better preserved in human infants with complete visual deprivation than in those who can see diffuse light but not patterned visual input has important clinical implications.

16.
Biochemistry ; 58(47): 4751-4760, 2019 11 26.
Artigo em Inglês | MEDLINE | ID: mdl-31271025

RESUMO

Knotted and slipknotted proteins are topologically complex. Understanding their folding and unfolding mechanism has attracted considerable interest. Here we combined protein engineering, single-molecule optical tweezers, and steered molecular dynamics (SMD) simulations to investigate the mechanical unfolding and folding of a slipknotted protein pyruvoyl-dependent arginine decarboxylase (PADC). In its slipknotted structure, PADC contains a long threaded loop (85 residues), which is almost twice the size of the knotting loop. When stretched from its N- and C-termini, the majority of PADC can be readily unfolded in a two-state manner, and the slipknotted structure was untied. A small percentage of PADC unfolded following a three-state pathway involving the formation of an unfolding intermediate state. These unfolding intermediate states showed a broad distribution of contour length increments, suggesting that they did not have a well-defined specific structure. SMD simulations revealed the main free energy barrier to the unfolding of PADC and suggested that the unfolding intermediate states may originate from the frication of polypeptide chain sliding during the process of pulling the threaded loop out of the knotting loop. Upon relaxation, a small percentage of the unfolded and untied PADC polypeptide chain can refold back to its native slipknotted conformation, but a large fraction can only reach a misfolded state. Our results revealed the complexity of the mechanical unfolding and refolding of a slipknotted protein with a long threaded loop.


Assuntos
Carboxiliases/química , Simulação de Dinâmica Molecular , Desdobramento de Proteína , Animais , Humanos , Pinças Ópticas , Conformação Proteica , Dobramento de Proteína , Termodinâmica
17.
J Stroke Cerebrovasc Dis ; 28(9): 2555-2562, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31248739

RESUMO

OBJECTIVE: The present study aimed to investigate the effects of Mesenchymal stem cells/glial cell line derived neurotrophic factor (MSCs/GDNF) transplantation on nerve reconstruction in rats with intracerebral hemorrhage. METHODS: GDNF transduction to MSCs was using adenovirus vector pAdEasy-1-pAdTrack-CMV prepared. Intracerebral hemorrhage (ICH) was induced by injection of collagenase and heparin into the caudate putamen. At the third day after a collagenase-induced ICH, adult male SD rats were randomly divided into saline group, MSCs group and MSCs/GDNF group. Immunofluorescence and RT-PCR were performed to detect the differentiation of MSCs or MSCs with an adenovirus vector encoding GDNF gene in vivo and in vitro. RESULT: After 6 hours of induction, both MSCs and MSCs/GDNF expressed neuro or glial specific markers and synaptic-associated proteins (SYN, GAP-43, PSD-95); additionally, they secreted bioactive compounds (BDNF, NGF-ß). MSCs/GDNF transplantation, compared to MSCs and saline solution injection, significantly improved neurological functions after ICH. The grafted MSCs or MSCs/GDNF survived in the striatum after 2 weeks of transplantation and expressed the neural cell-specific biomarkers NSE, MAP2, and GFAP. CONCLUSION: These findings demonstrate that MSCs/GDNF transplantation contributes to improved neurological function in experimental ICH rats. The mechanisms are possibly due to neuronal replacement and enhanced neurotrophic factor secretion.


Assuntos
Encéfalo/fisiopatologia , Hemorragia Cerebral/cirurgia , Terapia Genética/métodos , Fator Neurotrófico Derivado de Linhagem de Célula Glial/biossíntese , Transplante de Células-Tronco Mesenquimais/métodos , Células-Tronco Mesenquimais/metabolismo , Regeneração Nervosa , Células-Tronco Neurais/transplante , Transfecção , Animais , Biomarcadores/metabolismo , Encéfalo/metabolismo , Encéfalo/patologia , Células Cultivadas , Hemorragia Cerebral/genética , Hemorragia Cerebral/metabolismo , Hemorragia Cerebral/fisiopatologia , Modelos Animais de Doenças , Fator Neurotrófico Derivado de Linhagem de Célula Glial/genética , Masculino , Células-Tronco Neurais/metabolismo , Neurogênese , Fenótipo , Ratos Sprague-Dawley , Recuperação de Função Fisiológica , Fatores de Tempo
18.
Brain Res Bull ; 149: 42-52, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31002912

RESUMO

OBJECTIVE: Although transplantation of bone marrow-derived mesenchymal stem cells (MSCs) has shown beneficial effects on stroke, lower survival of MSCs limits effects. Extracellular regulating kinase 1/2 signaling (ERK1/2) is crucial for cell survival, differentiation, and proliferation. This study was designed to explore whether MSCs modified by over-expressing ERK1/2 may reinforce beneficial effects on stroke in rats. METHODS: rat MSCs transfected with ERK1/2 and empty lentivirus to generate MSCs overexpressing ERK1/2 (ERK/MSCs) and MSCs (as a control), respectively. In vitro, ERK/MSCs were plated and exposed to glutamate-induced condition, and viability of ERK/MSCs was measured. Furthermore, neural induction of ERK/MSCs was investigated in vitro. Cerebral ischemic rats were induced by occluding middle cerebral artery, and then were stereotaxically injected into ipsilateral right lateral ventricle with ERK/MSCs or MSCs 3 days after stroke and survived for 7 or 14 days after injection. RESULTS: ERK/MSCs showed better viability in physiological and glutamate-induced neurotoxic conditions compared to MSCs. After neural induction, more neurons were be differentiated from ERK/MSCs than from MSCs. After transplantation, more numbers of grafted cells and improved functional recovery were observed in ERK/MSCs-treated rats compared with MSCs-treated rats. Compared with MSCs treatment, ERK/MSCs treatment significantly increased proliferation of neural stem cells in the subventricle zone (SVZ) and the MAP2/nestin double-labeled cells adjacent to the SVZ, enhanced the numbers of reactive astrocytes while suppressed microglial activation. Besides, TNF-α level was elevated in ERK/MSCs-treated rats. CONCLUSION: ERK/MSCs transplantation showed better functional recovery after stroke in rats, likely in part through enhancing survival of MSCs and possibly by modulating the proliferation, neuronal de-differentiation and neuroinflammation.


Assuntos
Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Transplante de Células-Tronco Mesenquimais/métodos , Acidente Vascular Cerebral/prevenção & controle , Animais , Isquemia Encefálica/fisiopatologia , Diferenciação Celular/fisiologia , Células Cultivadas , Modelos Animais de Doenças , Infarto da Artéria Cerebral Média/fisiopatologia , Sistema de Sinalização das MAP Quinases/fisiologia , Masculino , Células-Tronco Mesenquimais/fisiologia , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 1 Ativada por Mitógeno/farmacologia , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno/farmacologia , Células-Tronco Neurais/fisiologia , Neurônios/fisiologia , Ratos , Ratos Wistar , Recuperação de Função Fisiológica/fisiologia , Acidente Vascular Cerebral/tratamento farmacológico , Acidente Vascular Cerebral/fisiopatologia
19.
Nano Lett ; 18(11): 6665-6671, 2018 11 14.
Artigo em Inglês | MEDLINE | ID: mdl-30350652

RESUMO

Nanocrystals (NCs) with identical components and sizes but different crystal structures could not be distinguished by conventional absorption and emission spectra. Herein, we find that circular dichroism (CD) spectroscopy can easily distinguish the CdSe nanoplatelets (NPLs) with different crystal structures of wurtzite (WZ) and zincblende (ZB) with the help of chiral l- or d-cysteine ligands. In particular, the CD signs of the first excitonic transitions in WZ and ZB NPLs capped by the same chiral cysteine are opposite. Theoretic calculation supports the viewpoint of different crystal structures and surfaces arrangements between WZ and ZB NPLs contributing to this significant phenomenon. The CD peaks appearing at the first excitonic transition band of WZ or ZB CdSe NPLs are clearly assigned to the different transition polarizations along 4p( x,y,z),Se → 5sCd or 4p( x,y),Se → 5sCd. This work not only provides a deep insight into the origin of the optical activity inside chiral semiconductor nanomaterials but also proposes the design principle of chiral semiconductor nanocrystals with high optic activity.

20.
Clin Breast Cancer ; 18(6): e1347-e1352, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30078612

RESUMO

BACKGROUND: The American Joint Committee on Cancer anatomic stage/prognostic group template arguably is the most powerful in predicting breast cancer outcomes because it considers the primary tumor, regional lymph node involvement, and presence of distant metastasis. However, other tumor and host characteristics have also been proved to be of prognostic value, including histologic grade and estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 status. Thus, the 8th edition of the American Joint Committee on Cancer consolidated these factors into clinical prognostic stage groups. MATERIALS AND METHODS: We validated the clinical prognostic stage groups compared with the anatomic stage groups in a cohort of 3322 breast cancer patients. RESULTS: Compared with the anatomic stage, application of the clinical prognostic stage assigned 27.7% and 24.7% of cases to higher and lower stage groups, respectively. In 14% and 2.8% of cases, the assignment of clinical prognostic stage varied by 2 and 3 anatomic stages up or down, respectively. The Cox proportional hazard model demonstrated superior discriminatory power for clinical prognostic stage (overall χ2, 464.5; P < .0001 vs. χ2, 363.9; P < .0001). A pairwise comparison revealed that significant improvement was especially observed for patients with clinically prognostic stage I and III disease compared with that of the anatomic stage groups. CONCLUSION: The new clinical prognostic stage provides a more powerful, yet imperfect, tool for predicting breast cancer outcomes. Further refinement of this system might be necessary in the pursuit of precision medicine.


Assuntos
Neoplasias da Mama/patologia , Estadiamento de Neoplasias/normas , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Biomarcadores Tumorais/metabolismo , Neoplasias da Mama/classificação , Neoplasias da Mama/cirurgia , Feminino , Seguimentos , Humanos , Pessoa de Meia-Idade , Prognóstico , Receptor ErbB-2/metabolismo , Receptores de Estrogênio/metabolismo , Receptores de Progesterona/metabolismo , Taxa de Sobrevida , Adulto Jovem
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