Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 91
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Pest Manag Sci ; 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-32061021

RESUMO

BACKGROUND: The aphid alarm pheromone, (E)-ß-farnesene (EßF), is a natural product secreted from the aphid cornicle as a signal to warn companions of danger. Odorant binding proteins (OBPs) are the vital targets in insect signal transduction pathways. To improve bioactivity of EßF as more economic and stable aphid control agents, EßF derivatives containing an active substructure, salicylic acid moiety, were designed, synthesized, and evaluated for their bioactivities in a structure-function study under laboratory conditions. RESULTS: EßF derivatives, (E)-3,7-dimethylocta-2,6-dien-1-yl-2-hydroxy-3-methylbenzoate and (E)-3,7-dimethylocta-2,6-dien-1-yl-2-hydroxy-3-methoxybenzoate showed outstanding aphid-repellent activity at a dose of 5 µg against Acyrthosiphon pisum (repellency proportions of 67.3% and 71.2%, respectively) and Myzus persicae (repellency proportions of 80.0% and 74.4%, respectively) in laboratory. EßF and most of its derivatives bound strongly to ApisOBP9 with a higher affinity than those of the reported potential targets AphisOBP3 and ApisOBP7. The binding affinities to these three ApisOBPs were generally consistent with the in vivo aphid-repellent activity. A molecular docking study suggested that the hydrophobic effect was crucial for the interactions between the derivatives and the OBPs. CONCLUSION: New EßF derivatives containing salicylic acid moiety and their repellent activity, binding mechanism with three potential OBPs are presented. A new OBP, ApisOBP9, was characterized as a potential EßF and EßF derivatives binding protein for the first time. The hydrophobic nature of these analogues is responsible for their activity. Two analogues 3b and 3e with outstanding aphid-repellent activity could be new leads for aphid control agents. This article is protected by copyright. All rights reserved.

2.
Brain Res Bull ; 154: 9-20, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31626954

RESUMO

Hypertension is a common complication of metabolic abnormalities associated with cardiovascular system and characterized by sexual dimorphism in mammals. Fibroblast growth factor-21 (FGF-21) plays a critical role in metabolic-disorder related hypertension through the afferent loop of baroreflex. However, the gender difference in FGF-21-mediated blood pressure (BP) regulation via sexual dimorphic expression of FGFRs in the nodose (NG) and nucleus tractus solitarius (NTS) were not elucidated in physiological and genomic form of hypertension. The gene and protein expression of FGFRs were tested by qRT-PCR, immunoblotting and immunostaining; the serum level of FGF21 was tested using ELISA; The BP was monitored while FGF21 was nodose microinjected. The results showed that more potent BP reduction was confirmed in female vs. male rats by nodose microinjection of rhFGF-21 along with higher expression of FGFR2 and FGFR4 in the nodose compared with age-match male and ovariectomized (OVX) rats, rather than other receptor subtypes, which is consistent well with immunohistochemical analysis. Additionally, serum FGF-21 was significantly higher in female-WKY, and this level of FGF-21 was dramatically declined in spontaneous hypertensive rats (SHR) with significant down-regulation of FGFR1/R4 for male-SHR and FGFR2/FGFR4 for female-SHR, respectively. Apparently, high BP of SHR of either sex could be reduced by rhFGF-21 nodose microinjection. These data extends our current understanding that sexual-specific distribution/expression of FGF-21/FGFRs is likely to contribute at least partially to sexual dimorphism of baroreflex afferent function on BP regulation in rats. FGF-21-mdiated BP reduction sheds new light on clinical management of primary/genomic form of hypertension.

3.
J Clin Neurosci ; 71: 217-225, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31883812

RESUMO

The accumulation of α-syn which induce endoplasmic reticulum stress (ERS) and mediate various signaling pathways involved in DA neuronal degeneration, and the apoptosis of dopamine (DA) neurons are pathological markers of Parkinson's disease (PD). High-temperature requirement protein A2 (HtrA2) is synthesized in the endoplasmic reticulum, and the expression level of HtrA2 can be upregulated by drugs or by unfolded proteins. Ucf-101 is a specific inhibitor of HtrA2, and studies have shown that Ucf-101 reduced apoptosis in PC12 cells. Our study showed that PC12 cells treated with 60 µM 6-OHDA for 24 h had significantly decreased cell viability compared to that of controls. A low concentration (2.5 µM) of Ucf-101 decreased the apoptosis rate of the PD cell model, but a high concentration (≥10 µM) increased the apoptosis rate, compared to that of controls. 6-OHDA upregulated the expression of HtrA2, α-syn, CHOP, Grp78 and active caspase-3 and reduced the levels of TH and XIAP. Ucf-101 reduced the level of ERS and apoptosis bothin vivoandin vitro. The ratio of p-GSK3ß (Tyr216 to Ser9) increased in PD rats. However, Ucf-101 down-regulated the activation of GSK3ß and activated the Wnt/ß-catenin pathway that was caused by 6-OHDA. Ucf-101 activated the Wnt/ß-catenin pathway and significantly attenuated 6-OHDA-induced neurotoxicity, which was related to the inhibition of ERS and the reduction of the apoptosis rate of PC12 cells and DA neurons in the midbrain of PD rats. Ucf-101 has certain neuroprotective effects.

4.
J Mol Neurosci ; 2019 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-31833018

RESUMO

BACKGROUND: Triggering receptor expressed on myeloid cells 2 (TREM2) is a microglial surface receptor that mediates the degradation disorder of amyloid ß (Aß) in Alzheimer's disease. However, the role of TREM2 in Parkinson's disease (PD) and α-Synclein (α-Syn) degradation is largely unknown. METHODS: In this case-control study on Chinese population, we sequenced for polymorphisms in exon 2 of the TREM2 gene in 1,292 individuals, PD cases (n = 612), healthy controls (n = 680) by Sanger sequence, and compared the distribution of allelic frequencies between the two groups by the Fisher's exact test. Additionally, we developed and used the enzyme-linked immunosorbent assay to evaluated soluble TREM2 (sTREM2) levels in the cerebrospinal fluid (CSF), and plasma in partial of sequenced groups (55 PD and 40 healthy controls) analyzed their relationship with total a-syn (t-a-Syn). RESULTS: Two novel variants were detected in exon 2 of the TREM2 gene, namely, p.S81 N, p.G58D; however, these were not significantly associated with PD (612 PD and 680 healthy controls). sTREM2 in CSF was significantly upregulated in PD patients compared to healthy controls (433.1 ± 24.7 pg/mL vs. 275.2 ± 17.9 pg/mL, p < 0.0001), but not in plasma (281.7 ± 29.3 pg/mL vs. 257.8 ± 16.5 pg/mL, p = 0.805). In PD patients, sTREM2 was positively correlated with t-α-syn (r = 0.62, p = 0.0001) in CSF, but not in plasma (r = 0.02, p = 0.89). CONCLUSIONS: Although it may not indicate that exon 2 polymorphisms of TREM2 play a role in the pathogenesis of PD in the Chinese population, our findings described above highlight the relevance of CSF sTREM2 as a promising biomarker and are extremely possible to the therapeutic target for PD in the future.

5.
Pest Manag Sci ; 2019 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-31840904

RESUMO

BACKGROUND: The discovery of ecofriendly insecticides through a new strategy for aphid control is important because of the substantial resistance and unexpected eco-toxicity to honeybees caused by traditional insecticides. The insect kinins, a class of multifunctional insect neuropeptides, are considered for potential application in pest control. In our previous work we developed several series of insect kinin analogues and found a promising lead II-1 with good aphicidal activity. To seek further eco-friendly aphicides, the optimization of II-1 is carried out in this study. RESULTS: Fifteen novel Yaa3 modified analogues based on the lead II-1 were synthesized. The aphicidal tests indicated that IV-3, IV-5 and IV-10 exhibited significant activity against the soybean aphid Aphis glycines with LC50 values of 0.0029, 0.0072 and 0.0086 mmol L-1 , respectively, higher than that of lead II-1 and the commercial Pymetrozine. The molecular modeling results showed that analogues II-1, IV-3, IV-5, IV-7 and IV-10 formed a ß-turn-like conformation, while the conformation of analogues IV-1, IV-2 and IV-9 seemed to be linear. Some structural elements favorable for the activity were proposed based on the conformation-activity relationship of the analogues. CONCLUSION: Insect kinin analogues derived from lead II-1 by modifying the hydrolysis site Yaa3 with natural, sterically hindered α- and ß-amino acids showed great potential as eco-friendly insecticides. Inspiringly, the most active analogue IV-3 can be a candidate for further development. The ß-turn-like conformation and the orientation of the aromatic rings of the side chain of Phe2 and Trp4 may be critical factors beneficial to activity. © 2019 Society of Chemical Industry.

6.
Biomed Res Int ; 2019: 2072635, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31781596

RESUMO

Objectives: To explore the differences of immune disorders in peripheral blood between patients with early-onset Parkinson's disease (EOPD) and late-onset Parkinson's disease (LOPD). Methods: We retrospectively reviewed medical records of Parkinson's disease (PD) patients and healthy controls between June 2002 and July 2017. At last, we included 117 PD patients who were divided into EOPD and LOPD according to whether onset age of PD was after 50 and 99 controls divided into E-Control (match for EOPD) and L-Control (match for LOPD) according to whether their age was after 53 which was onset age plus median of disease duration. We compared the ratios of cells between multiple groups and performed the multinominal logistic regression analysis to explore the relationship between ratios and subtypes of PD. We also carried out the receiver operating characteristic (ROC) curve analysis to estimate the diagnostic value of the variable. Results: Lymphocyte-red blood cell ratio (LRR) was lower in LOPD compared with that in EOPD or L-Control. LRR was also negatively associated with LOPD (OR: 0.623; 95% CI: 0.397-0.980; P=0.040). The ROC curve analysis showed the optimal cutoff value of 4.53 (×10-4) of LRR for discrimination of LOPD versus L-Control (sensitivity: 0.596, specificity: 0.764). The area under curve (AUC) was 0.721. As for LOPD versus EOPD, the optimal threshold of LRR was 4.10 (×10-4) (sensitivity: 0.516, specificity: 0.745). AUC was 0.641. Conclusions: Peripheral immune disorders might play an important part in the pathological progression of LOPD. Also, LRR has potential diagnostic value.

7.
BMC Plant Biol ; 19(1): 444, 2019 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-31651252

RESUMO

BACKGROUND: The plant-specific homeodomain-leucine zipper class IV (HD-ZIP IV) gene family has been involved in the regulation of epidermal development. RESULTS: Fifteen genes coding for HD-ZIP IV proteins were identified (NtHD-ZIP-IV-1 to NtHD-ZIP-IV-15) based on the genome of N. tabacum. Four major domains (HD, ZIP, SAD and START) were present in these proteins. Tissue expression pattern analysis indicated that NtHD-ZIP-IV-1, - 2, - 3, - 10, and - 12 may be associated with trichome development; NtHD-ZIP-IV-8 was expressed only in cotyledons; NtHD-ZIP-IV-9 only in the leaf and stem epidermis; NtHD-ZIP-IV-11 only in leaves; and NtHD-ZIP-IV-15 only in the root and stem epidermis. We found that jasmonates may induce the generation of glandular trichomes, and that NtHD-ZIP-IV-1, - 2, - 5, and - 7 were response to MeJA treatment. Dynamic expression under abiotic stress and after application of phytohormones indicated that most NtHD-ZIP IV genes were induced by heat, cold, salt and drought. Furthermore, most of these genes were induced by gibberellic acid, 6-benzylaminopurine, and salicylic acid, but were inhibited by abscisic acid. NtHD-ZIP IV genes were sensitive to heat, but insensitive to osmotic stress. CONCLUSION: NtHD-ZIP IV genes are implicated in a complex regulatory gene network controlling epidermal development and abiotic stress responses. The present study provides evidence to elucidate the gene functions of NtHD-ZIP IVs during epidermal development and stress response.

9.
Plant Physiol Biochem ; 141: 388-397, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31226508

RESUMO

Members of the Jasmonate ZIM domain (JAZ) proteins act as transcriptional repressors in the jasmonate (JA) hormonal response. To characterize the potential roles of JAZ gene family in plant development and abiotic stress response, fifteen JAZs were identified based on the genome of Nicotiana tabacum. Structural analysis confirmed the presence of single Jas and TIFY motif. Tissue expression pattern analysis indicated that NtJAZ-2, -3, -5, and -10 were highly expressed in roots and NtJAZ-11 was expressed only in the cotyledons. The transcript level of NtJAZ-3, -5, -9, and -10 in the stem epidermis was higher than that in the stem without epidermis. Dynamic expression of NtJAZs exposed to abiotic stress and phytohormone indicated that the expression of most NtJAZs was activated by salicylic acid, methyl jasmonate, gibberellic acid, cold, salt, and heat stresses. With abscisic acid treatment, NtJAZ-1, -2, and -3 were not activated; NtJAZ-4, -5, and -6 were up-regulated; and the remaining NtJAZ genes were inhibited. With drought stress, the expression of NtJAZ-1, -2, -3, -4, -5, -6, -7, and -8 was up-regulated, whereas the transcript of the remaining genes was inhibited. Moreover, high concentration MeJA (more than 1 mM MeJA) had an effect on secreting trichome induction, but inhabited the plant growth. Nine NtJAZs may play important role in secreting trichome induction. These results indicate that the JAZ proteins are convergence points for various phytohormone signal networks, which are involved in abiotic stress responses.


Assuntos
Proteínas de Plantas/metabolismo , Proteínas Repressoras/metabolismo , Estresse Fisiológico , Tabaco/genética , Tabaco/metabolismo , Tricomas/metabolismo , Acetatos/metabolismo , Motivos de Aminoácidos , Arabidopsis/metabolismo , Cromossomos/metabolismo , Ciclopentanos/metabolismo , Bases de Dados Genéticas , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Cadeias de Markov , Oxilipinas/metabolismo , Filogenia , Reguladores de Crescimento de Planta/metabolismo , Proteínas de Plantas/genética , Raízes de Plantas/metabolismo , Proteínas Repressoras/genética , Transdução de Sinais , Fatores de Transcrição/genética
10.
Bioorg Chem ; 87: 56-69, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30877868

RESUMO

Botrytis cinerea is an economically important fungal pathogen with a host range of over 200 plant species. Unfortunately, gray mold disease caused by B. cinerea has not been effectively controlled because of its high risk for fungicide resistance development. As a part of our ongoing efforts to develop novel sulfonamides as agricultural fungicides against Botrytis cinerea, we introduced 2-aminoethanesulfonic acid (taurine) substructure, designed and synthesized a series of novel 2-substituted acylaminoethylsulfonamides. The newly synthesized sulfonamides were evaluated in vitro and in vivo for their fungicidal activity against Botrytis cinerea, of which the 2-ethoxyacetylamide derivative (V-A-12, EC50 = 0.66 mg·L-1) exhibited the highest potency in vitro and superior fungicidal activity compared with procymidone (EC50 = 1.06 mg·L-1). In vivo bioassay indicated that compound V-A-12 could be effective for the control of tomato gray mold. Moreover, the structure-activity relationship of these sulfonamides was analyzed by establishing a three-dimensional quantitative structure-activity relationship (3D-QSAR) model, which can provide guidance for the development of sulfonamides as fungicides. Finally, the effeicacy of sulfonamide derivatives was again verified in the activity evaluation against resistant Botrytis cinerea strains. These results further enhance the development value of 2-substituted acylaminoethylsulfonamides to control the tomato gray mold.

11.
Bioorg Med Chem Lett ; 29(7): 890-895, 2019 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-30765188

RESUMO

Allatostatins (AST) are neuropeptides originally described as inhibitors of juvenile hormone (JH) synthesis in insects. Consequently, they have been considered as potential lead compounds for the discovery of new insect growth regulators (IGRs). In the present work, receptor-based three-dimensional quantitative structure-activity relationship (3D-QSAR) was studied with 48 AST analogs, and a general approach for novel potent bioactive AST analogs is proposed. Hence, six novel AST analogs were designed and synthesized. Bioassays indicated that the majority novel analogs exhibited potent JH inhibitory activity, especially analog A6 (IC50: 3.79 nmol/L), which can be used as lead compound to develop new IGRs.

12.
ACS Chem Neurosci ; 10(2): 803-811, 2019 02 20.
Artigo em Inglês | MEDLINE | ID: mdl-30289236

RESUMO

Many publications reported that genetic dysfunction mediates abnormal immune responses in the brain, which is important for the development of neurodegenerative diseases, especially for Parkinson's disease (PD). This immune disorder results in subsequent inflammatory reaction, which stimulates microglia or other immune cells to secrete cytokines and chemokines and disturbs the proportion of peripheral blood lymphocyte subsets contributing to dopaminergic (DA) neuron apoptosis. Furthermore, the abnormal immune related signal pathways caused by genetic variants promote chronic inflammation destroying the blood-brain barrier, which allows infiltration of different molecules and blood cells into the central nervous system (CNS) exerting toxicity on DA neurons. As a result, the inflammatory reaction in the CNS accelerates the progression of Parkinson's disease and promotes α-synuclein aggregation and diffusion among DA neurons in the procession of Parkinson's disease. Thus, for disease evaluation, the genetic mediated abnormal immune response in PD may be assessed based on the multiple immune molecules and inflammatory factors, as well as the ratio of lymphocyte subsets from PD patient's peripheral blood as potential biomarkers.

13.
Transl Neurodegener ; 7: 19, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30128145

RESUMO

Background: Abnormal expression of major histocompatibility complex class I (MHC-I) is increased in dopaminergic (DA) neurons in the substantia nigra (SN) in Parkinson's disease (PD). Low-molecular-mass protein 7 (ß5i) is a proteolytic subunit of the immunoproteasome that regulates protein degradation and the MHC pathway in immune cells. Methods: In this study, we investigated the role of ß5i in DA neurons using a 6-hydroxydopamine (6-OHDA) model in vitro and vivo. Results: We showed that 6-OHDA upregulated ß5i expression in DA neurons in a concentration- and time-dependent manner. Inhibition and downregulation of ß5i induced the expression of glucose-regulated protein (Bip) and exacerbated 6-OHDA neurotoxicity in DA neurons. The inhibition of ß5i further promoted the activation of Caspase 3-related pathways induced by 6-OHDA. ß5i also activated transporter associated with antigen processing 1 (TAP1) and promoted MHC-I expression on DA neurons. Conclusion: Taken together, our data suggest that ß5i is activated in DA neurons under 6-OHDA treatment and may play a neuroprotective role in PD.

15.
Molecules ; 23(4)2018 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-29614008

RESUMO

Insect G protein coupled receptors (GPCRs) have important roles in modulating biology, physiology and behavior. They have been identified as candidate targets for next-generation insecticides, yet these targets have been relatively poorly exploited for insect control. In this study, we present a pipeline of novel Manduca sexta allatotropin (Manse-AT) antagonist discovery with homology modeling, docking, molecular dynamics simulation and structure-activity relationship. A series of truncated and alanine-replacement analogs of Manse-AT were assayed for the stimulation of juvenile hormone biosynthesis. The minimum sequence required to retain potent biological activity is the C-terminal amidated octapeptide Manse-AT (6-13). We identified three residues essential for bioactivity (Thr4, Arg6 and Phe8) by assaying alanine-replacement analogs of Manse-AT (6-13). Alanine replacement of other residues resulted in reduced potency but bioactivity was retained. The 3D structure of the receptor (Manse-ATR) was built and the binding pocket was identified. The binding affinities of all the analogs were estimated by calculating the free energy of binding. The calculated binding affinities corresponded to the biological activities of the analogs, which supporting our localization of the binding pocket. Then, based on the docking and molecular dynamics studies of Manse-AT (10-13), we described it can act as a potent Manse-AT antagonist. The antagonistic effect on JH biosynthesis of Manse-AT (10-13) validated our hypothesis. The IC50 value of antagonist Manse-AT (10-13) is 0.9 nM. The structure-activity relationship of antagonist Manse-AT (10-13) was also studied for the further purpose of investigating theoretically the structure factors influencing activity. These data will be useful for the design of new Manse-AT agonist and antagonist as potential pest control agents.


Assuntos
Hormônios de Inseto/antagonistas & inibidores , Hormônios de Inseto/metabolismo , Manduca/metabolismo , Neuropeptídeos/antagonistas & inibidores , Neuropeptídeos/metabolismo , Animais , Hormônios de Inseto/química , Inseticidas/química , Neuropeptídeos/química , Receptores Acoplados a Proteínas-G/antagonistas & inibidores , Receptores Acoplados a Proteínas-G/química , Receptores Acoplados a Proteínas-G/metabolismo , Relação Estrutura-Atividade
16.
J Mol Model ; 24(3): 70, 2018 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-29488109

RESUMO

Odorant-binding proteins (OBPs) play an important role as ligand-transfer filters in olfactory recognition in insects. (E)-ß-farnesene (EBF) is the main component of the aphid alarm pheromone and could keep aphids away from crops to prevent damage. Computational insight into the molecular binding mode of EBF analogs containing a heterocycle based on the structure of Megoura viciae OBP 3 (MvicOBP3) was obtained by molecular docking and molecular dynamics simulations. The results showed that high affinity EBF analogs substituted with an aromatic ring present a unique binding conformation in the surface cavity of MvicOBP3. A long EBF chain was located inside the cavity and was surrounded by many hydrophobic residues, while the substituted aromatic ring was exposed to the outside due to limitations from the formation of multiple hydrogen bonds. However, the low activity EBF analogs displayed an exactly inverted binding pose, with EBF loaded on the external side of the protein cavity. The affinity of the recently synthesized EBF analogs containing a triazine ring was evaluated in silico based on the binding modes described above and in vitro through fluorescence competitive binding assay reported later. Compound N1 not only showed a similar binding conformation to that of the high affinity analogs but was also found to have a much higher docking score and binding affinity than the other analogs. In addition, the docking score results correlated well with the predicted logP values for these EBF analogs, suggesting highly hydrophobic interactions between the protein and ligand. These studies provide an in silico screening model for the binding affinity of EBF analogs in order to guide their rational design based on aphid OBPs.


Assuntos
Afídeos/química , Receptores Odorantes/química , Sesquiterpenos/química , Animais , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Ligação Proteica , Receptores Odorantes/metabolismo , Triazinas/química
17.
J Mol Graph Model ; 81: 77-85, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29529496

RESUMO

Insect growth is regulated by the steroid hormone 20-hydroxyecdysone (20E), which works via the ecdysone receptor (EcR). To identify biologically active and novel ecdysone agonists/antagonists, ligand/structure-based virtual screening combined with pharmacophore modeling and molecular docking was performed to identify novel nonsteroidal lead compounds. Nine molecules were screened and selected for an in vitro cell-based reporter bioassay. The results showed that VS-006 and VS-009 exhibited antagonistic activity in S2 cells, whereas only VS-006 exhibited antagonistic activity in Bm5 cells. Molecular dynamic simulation of VS-006 complexed with the ligand binding domain of EcR validated the binding stability of VS-006 and highlighted the key residues for further lead optimization.


Assuntos
Descoberta de Drogas , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Receptores de Esteroides/química , Descoberta de Drogas/métodos , Regulação da Expressão Gênica/efeitos dos fármacos , Genes Reporter , Ligantes , Conformação Molecular , Estrutura Molecular , Ligação Proteica , Receptores de Esteroides/agonistas , Receptores de Esteroides/antagonistas & inibidores , Bibliotecas de Moléculas Pequenas , Relação Estrutura-Atividade
18.
J Neurochem ; 145(1): 34-50, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29364516

RESUMO

Recent studies have strongly shown that cell-to-cell transmission of neuropathogenic proteins is a common mechanism for the development of neurodegenerative diseases. However, the underlying cause is complex and little is known. Although distinct processes are involved in the pathogenesis of various diseases, they all share the common feature of iron accumulation, an attribute that is particularly prominent in synucleinopathies. However, whether iron is a cofactor in facilitating the spread of α-synuclein remains unclear. Here, we constructed a cell-to-cell transmission model of α-synuclein using SN4741 cell line based on adenovirus vectors. Cells were treated with FeCl2, and α-synuclein aggregation and transmission were then evaluated. In addition, the possible mechanisms were investigated through gene knockdown or over-expression. Our results demonstrated that iron promoted α-synuclein aggregation and transmission by inhibiting autophagosome-lysosome fusion. Furthermore, iron decreased the expression of nuclear transcription factor EB (TFEB), a master transcriptional regulator of autophagosome-lysosome fusion, and inhibited its nuclear translocation through activating AKT/mTORC1 signaling. After silencing TFEB, ratios of α-synuclein aggregation and transmission were not significantly altered by the presence of iron; on the other hand, when TFEB was over-expressed, the transmission of α-synuclein induced by iron was obviously reversed; suggesting the mechanism by which iron promotes α-synuclein transmission may be mediated by TFEB. Taken together, our data reveal a previously unknown relationship between iron and α-synuclein, and identify TFEB as not only a potential target for preventing α-synuclein transmission, but also a critical factor for iron-induced α-synuclein aggregation and transmission. Indeed, this newly discovered role of iron and TFEB in synucleinopathies may provide novel targets for developing therapeutic strategies to prevent α-synuclein transmission in Parkinson's disease.


Assuntos
Autofagossomos/metabolismo , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/metabolismo , Ferro/metabolismo , Lisossomos/metabolismo , Agregação Patológica de Proteínas/metabolismo , alfa-Sinucleína/metabolismo , Animais , Autofagossomos/efeitos dos fármacos , Comunicação Celular/efeitos dos fármacos , Linhagem Celular , Humanos , Ferro/farmacologia , Lisossomos/efeitos dos fármacos , Camundongos
19.
Brain Res ; 1678: 129-137, 2018 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-29066369

RESUMO

In Alzheimer's disease (AD), dementia severity correlates most strongly with decreased synapse density in the hippocampus and cerebral cortex. Although studies in rodents have established that hippocampal long-term potentiation (LTP) is inhibited by soluble oligomers of beta-amyloid (Aß), the synaptic mechanisms remain unclear. Here, field excitatory postsynaptic potentials (fEPSP) recordings were made in the CA1 region of mouse hippocampal slices. The medium of APP-expressing CHO cells, which contain soluble forms of Aß including small oligomers, inhibited LTP and facilitated long-term depression (LTD), thus making the LTP/LTD curve shift toward the right. This phenomenon could be mimicked by the non-selective glutamate transporter inhibitor, DL-TBOA. More specifically, the Aß impaired LTP and facilitated LTD were occluded by the selective astrocytic glutamate transporter inhibitors, TFB-TBOA. In cultured astrocytes, the Aß oligomers also decrease astrocytic glutamate transporters (EAAT1, EAAT2) expression. We conclude that soluble Aß oligomers decrease the activation of astrocytic glutamate transporters, thereby impairing synaptic plasticity.


Assuntos
Sistema X-AG de Transporte de Aminoácidos/metabolismo , Sinapses/metabolismo , Sinapses/fisiologia , Doença de Alzheimer/metabolismo , Sistema X-AG de Transporte de Aminoácidos/antagonistas & inibidores , Peptídeos beta-Amiloides/metabolismo , Animais , Astrócitos/metabolismo , Região CA1 Hipocampal/metabolismo , Células CHO , Cricetulus , Fármacos atuantes sobre Aminoácidos Excitatórios/metabolismo , Potenciais Pós-Sinápticos Excitadores/fisiologia , Hipocampo/metabolismo , Potenciação de Longa Duração/efeitos dos fármacos , Potenciação de Longa Duração/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Plasticidade Neuronal/efeitos dos fármacos , Neurônios/metabolismo , Técnicas de Patch-Clamp , Fragmentos de Peptídeos/metabolismo
20.
Molecules ; 22(12)2017 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-29232885

RESUMO

In order to discover novel eco-friendly lead compounds for plant pathogenic fungi control, a series of benzaldehyde thiosemicarbazide derivatives with a piperidine moiety have been designed and synthesized. Fungicidal activities of all the synthesized compounds were evaluated in vitro. The results indicated that all the title compounds exhibited moderate to good fungicidal activities. Compound 3b displayed excellent activities against Pythium aphanidermatum, Rhizoctonia solani, Valsa mali, and Gaeu-mannomyces graminsis, with EC50 values lower than 10 µg/mL. Especially, in the case of Pythium aphanidermatum, its activity (EC50 = 1.6 µg/mL) is superior to the commercial azoxystrobin (EC50 = 16.9 µg/mL) and close to fluopicolide (EC50 = 1.0 µg/mL). Initial structure-activity relationship (SAR) analysis showed that the heterocyclic piperidine group can influence the biological activities of the title compounds significantly. The fungicidal activity of compounds with piperidine is better than that of compounds without piperidine. The highly-active compound 3b, with its simple structure and easy synthetic route, is worthy to be further studied as a new lead fungicide.


Assuntos
Antifúngicos/síntese química , Piperidinas/química , Plantas/microbiologia , Semicarbazidas/síntese química , Antifúngicos/química , Antifúngicos/farmacologia , Desenho de Drogas , Testes de Sensibilidade Microbiana , Estrutura Molecular , Doenças das Plantas/microbiologia , Doenças das Plantas/prevenção & controle , Pythium/efeitos dos fármacos , Rhizoctonia/efeitos dos fármacos , Semicarbazidas/química , Semicarbazidas/farmacologia , Relação Estrutura-Atividade
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA