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1.
J Biol Chem ; 300(5): 107226, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38537697

RESUMO

Epstein-Barr virus (EBV) is a human tumor virus associated with a variety of malignancies, including nasopharyngeal carcinoma, gastric cancers, and B-cell lymphomas. N6-methyladenosine (m6A) modifications modulate a wide range of cellular processes and participate in the regulation of virus-host cell interactions. Here, we discovered that EBV infection downregulates toll-like receptor 9 (TLR9) m6A modification levels and thus inhibits TLR9 expression. TLR9 has multiple m6A modification sites. Knockdown of METTL3, an m6A "writer", decreases TLR9 protein expression by inhibiting its mRNA stability. Mechanistically, Epstein-Barr nuclear antigen 1 increases METTL3 protein degradation via K48-linked ubiquitin-proteasome pathway. Additionally, YTHDF1 was identified as an m6A "reader" of TLR9, enhancing TLR9 expression by promoting mRNA translation in an m6A -dependent manner, which suggests that EBV inhibits TLR9 translation by "hijacking" host m6A modification mechanism. Using the METTL3 inhibitor STM2457 inhibits TLR9-induced B cell proliferation and immunoglobulin secretion, and opposes TLR9-induced immune responses to assist tumor cell immune escape. In clinical lymphoma samples, the expression of METTL3, YTHDF1, and TLR9 was highly correlated with immune cells infiltration. This study reveals a novel mechanism that EBV represses the important innate immunity molecule TLR9 through modulating the host m6A modification system.


Assuntos
Adenosina , Herpesvirus Humano 4 , Metiltransferases , Proteínas de Ligação a RNA , Receptor Toll-Like 9 , Humanos , Adenosina/análogos & derivados , Adenosina/metabolismo , Linfócitos B/metabolismo , Linfócitos B/imunologia , Linfócitos B/virologia , Infecções por Vírus Epstein-Barr/imunologia , Infecções por Vírus Epstein-Barr/metabolismo , Infecções por Vírus Epstein-Barr/virologia , Infecções por Vírus Epstein-Barr/genética , Herpesvirus Humano 4/imunologia , Herpesvirus Humano 4/genética , Herpesvirus Humano 4/metabolismo , Evasão da Resposta Imune , Metiltransferases/metabolismo , Metiltransferases/genética , Proteínas de Ligação a RNA/metabolismo , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/imunologia , Receptor Toll-Like 9/metabolismo , Receptor Toll-Like 9/genética , Linhagem Celular Tumoral
2.
J Biol Chem ; 299(9): 105082, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37495108

RESUMO

The development and progression of nasopharyngeal carcinoma (NPC) is closely associated with Epstein-Barr virus (EBV) infection. NPC is usually asymptomatic until it spreads to other sites, and more than 70% of cases are classified as locally advanced disease at diagnosis. EBV-positive nasopharyngeal cancer tissues express only limited viral latent proteins, but express high levels of the EBV-encoded BamHI-A rightward transcript (BART) miRNA molecules. Here, we report that EBV-miRNA-BART2-5p (BART2-5p) promotes NPC cell invasion and metastasis in vivo and in vitro but has no effect on NPC cell proliferation and apoptosis. In addition, BART2-5p altered the mRNA and miRNA expression profiles of NPC cells. The development of human tumors has been reported to be associated with altered miRNAs expression, and overall miRNAs expression is reduced in many types of tumors. We found that BART2-5p downregulated the expression of several miRNAs that could exert oncogenic functions. Mechanistically, BART2-5p directly targets the RNase III endonuclease DICER1, inhibiting its function of cleaving double-stranded stem-loop RNA into short double-stranded RNA, which in turn causes altered expression of a series of key epithelial-mesenchymal transition molecules, and reverting DICER1 expression can rescue this phenotype. Furthermore, analysis from clinical samples showed a negative correlation between BART2-5p and DICER1 expression. According to our study, high expression of BART2-5p in tissues and plasma of patients with NPC is associated with poor prognosis. Our results suggest that, BART2-5p can accelerate NPC metastasis through modulating miRNA profiles which are mediated by DICER1, implying a novel role of EBV miRNAs in the pathogenesis of NPC.


Assuntos
Infecções por Vírus Epstein-Barr , MicroRNAs , Carcinoma Nasofaríngeo , Neoplasias Nasofaríngeas , Ribonuclease III , Humanos , Infecções por Vírus Epstein-Barr/enzimologia , Infecções por Vírus Epstein-Barr/genética , Herpesvirus Humano 4/genética , MicroRNAs/genética , MicroRNAs/metabolismo , Carcinoma Nasofaríngeo/genética , Carcinoma Nasofaríngeo/patologia , Neoplasias Nasofaríngeas/genética , Neoplasias Nasofaríngeas/patologia , Ribonuclease III/genética , Ribonuclease III/metabolismo , Linhagem Celular Tumoral , Regulação Neoplásica da Expressão Gênica/genética , Movimento Celular/genética
3.
Cancer Immunol Immunother ; 73(1): 7, 2024 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-38231305

RESUMO

The search for effective combination therapy with immune checkpoint inhibitors (ICI) has become important for cancer patients who do not respond to the ICI well. Histone deacetylases (HDACs) inhibitors have attracted wide attention as anti-tumor agents. ACY-1215 is a selective inhibitor of HDAC6, which can inhibit the growth of a variety of tumor. We previously revealed that HDAC family is highly expressed in colorectal cancer specimens and mouse models. In this study, ACY-1215 was combined with anti-PD1 to treat tumor-bearing mice associated with colorectal cancer. ACY-1215 combined with anti-PD1 effectively inhibited the colorectal tumor growth. The expression of PD-L1 in tumor of mice were inhibited by ACY-1215 and anti-PD1 combination treatment, whereas some biomarkers reflecting T cell activation were upregulated. In a co-culture system of T cells and tumor cells, ACY-1215 helped T cells to kill tumor cells. Mechanically, HDAC6 enhanced the acetylation of STAT1 and inhibited the phosphorylation of STAT1, thus preventing STAT1 from entering the nucleus to activate PD-L1 transcription. This study reveals a novel regulatory mechanism of HDAC6 on non-histone substrates, especially on protein acetylation. HDAC6 inhibitors may be of great significance in tumor immunotherapy and related combination strategies.


Assuntos
Antígeno B7-H1 , Neoplasias Colorretais , Ácidos Hidroxâmicos , Pirimidinas , Humanos , Animais , Camundongos , Acetilação , Imunoterapia , Neoplasias Colorretais/tratamento farmacológico , Inibidores de Histona Desacetilases/farmacologia , Fator de Transcrição STAT1 , Desacetilase 6 de Histona
4.
Nanotechnology ; 35(15)2024 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-38150725

RESUMO

Obesity has become an ongoing global crisis, since it increases the risks of cardiovascular disease, type 2 diabetes, fatty liver, cognitive decline, and some cancers. Adipose tissue is closely associated with the disorder of lipid metabolism. Several efforts have been made toward the modulation of lipid accumulation, but have been hindered by poor efficiency of cellular uptake, low safety, and uncertain effective dosage. Herein, we design an Fe3O4microsphere-doped composite hydrogel (Fe3O4microspheres @chitosan/ß-glycerophosphate/collagen), termed as Fe3O4@Gel, as the magnetocaloric agent for magnetic hyperthermia therapy (MHT), aiming to promote lipolysis in white adipocytes. The experimental results show that the obtained Fe3O4@Gel displays a series of advantages, such as fast sol-gel transition, high biocompatibility, and excellent magneto-thermal performance. MHT, which is realized by Fe3O4@Gel subjected to an alternating magnetic field, leads to reduced lipid accumulation, lower triglyceride content, and increased mitochondrial activity in white adipocytes. This work shows that Fe3O4@Gel-mediated MHT can effectively promote lipolysis in white adipocytesin vitro, which provides a potential approach to treat obesity and associated metabolic disorders.


Assuntos
Diabetes Mellitus Tipo 2 , Hipertermia Induzida , Humanos , Lipólise , Adipócitos Brancos , Microesferas , Hidrogéis , Obesidade , Lipídeos , Hipertermia Induzida/métodos , Fenômenos Magnéticos
5.
Sichuan Da Xue Xue Bao Yi Xue Ban ; 54(6): 1227-1232, 2023 Nov 20.
Artigo em Zh | MEDLINE | ID: mdl-38162054

RESUMO

Objective: To investigate the metabolic outcomes of primary aldosteronism (PA) patients receiving adrenalectomy (ADX) or spironolactone treatment and the contributing factors to the metabolic outcomes. Methods: The clinical data of 70 patients with aldosterone-producing adenoma (APA) and 86 patients with idiopathic hyperaldosteronism (IHA) were retrospectively analyzed. All subjects received confirmatory diagnosis of APA or IHA at the Department of Endocrinology and Metabolism, West China Hospital between March 2018 and October 2020. APA patients underwent ADX, while IHA patients were given spironolactone, a mineralocorticoid receptor antagonist (MRA). After ADX or spironolactone treatment, the outcomes of the metabolic indicators and the inter-group differences between the APA patients and IHA patients were studied. Results: There was no significant difference between the baseline data of the APA group and those of the IHA group in terms of age, sex, duration of hypertension, maximum systolic blood pressure (SBP-max), maximum diastolic blood pressure (DBP-max), body mass index (BMI), fasting blood glucose (FBG), lipid parameters, and renal function. IHA patients had higher waist circumference, serum potassium, and plasma renin activity (PRA) than those of the APA patients (all P<0.05). All patients showed significant improvement in blood pressure, blood potassium, and plasma aldosterone at follow-up. However, they also showed increased triglycerides (TG) accompanied by deterioration in renal function (P≤0.001). Multiple regression showed that TG levels were associated with spironolactone treatment for IHA patients and post-treatment BMI and creatinine levels. Furthermore, APA patients showed improvement in their FBG after ADX (P=0.041), while IHA patients showed elevated levels of FBG after spironolactone treatment (P=0.037). Conclusion: After treatment, PA patients still may experience abnormal lipid metabolism and deteriorating renal function. Spironolactone therapy may give rise to worse glucolipid metabolism than ADX therapy does.


Assuntos
Hiperaldosteronismo , Hipertensão , Humanos , Espironolactona/uso terapêutico , Aldosterona , Hiperaldosteronismo/tratamento farmacológico , Hiperaldosteronismo/cirurgia , Hiperaldosteronismo/complicações , Adrenalectomia , Estudos Retrospectivos , Potássio
6.
Int J Mol Sci ; 22(23)2021 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-34884713

RESUMO

Hydrogen sulfide (H2S) plays a crucial role in regulating chilling tolerance. However, the role of hydrogen peroxide (H2O2) and auxin in H2S-induced signal transduction in the chilling stress response of plants was unclear. In this study, 1.0 mM exogenous H2O2 and 75 µM indole-3-acetic acid (IAA) significantly improved the chilling tolerance of cucumber seedlings, as demonstrated by the mild plant chilling injury symptoms, lower chilling injury index (CI), electrolyte leakage (EL), and malondialdehyde content (MDA) as well as higher levels of photosynthesis and cold-responsive genes under chilling stress. IAA-induced chilling tolerance was weakened by N, N'-dimethylthiourea (DMTU, a scavenger of H2O2), but the polar transport inhibitor of IAA (1-naphthylphthalamic acid, NPA) did not affect H2O2-induced mitigation of chilling stress. IAA significantly enhanced endogenous H2O2 synthesis, but H2O2 had minimal effects on endogenous IAA content in cucumber seedlings. In addition, the H2O2 scavenger DMTU, inhibitor of H2O2 synthesis (diphenyleneiodonium chloride, DPI), and IAA polar transport inhibitor NPA reduced H2S-induced chilling tolerance. Sodium hydrosulfide (NaHS) increased H2O2 and IAA levels, flavin monooxygenase (FMO) activity, and respiratory burst oxidase homolog (RBOH1) and FMO-like protein (YUCCA2) mRNA levels in cucumber seedlings. DMTU, DPI, and NPA diminished NaHS-induced H2O2 production, but DMTU and DPI did not affect IAA levels induced by NaHS during chilling stress. Taken together, the present data indicate that H2O2 as a downstream signal of IAA mediates H2S-induced chilling tolerance in cucumber seedlings.


Assuntos
Aclimatação , Cucumis sativus/metabolismo , Peróxido de Hidrogênio/metabolismo , Sulfeto de Hidrogênio/metabolismo , Ácidos Indolacéticos/metabolismo , Temperatura Baixa , Plântula/metabolismo
7.
Bioprocess Biosyst Eng ; 42(8): 1263-1271, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30982137

RESUMO

In recent years, an increasing number of defucosylated therapeutic antibodies have been applied in clinical practices due to their better efficacy compared to fucosylated counterparts. The establishment of stable and clonal manufacturing cell lines is the basis of therapeutic antibodies production. Bioprocess development of a new cell line is necessary for its future applications in the biopharmaceutical industry. We engineered a stable cell line expressing defucosylated anti-HER2 antibody based on an established α-1,6-fucosyltransferase (FUT8) gene knockout CHO-S cell line. The optimization of medium and feed was evaluated in a small-scale culture system. Then the optimal medium and feed were scaled up in a bioreactor system. After fed-batch culture over 13 days, we evaluated the cell growth, antibody yield, glycan compositions and bioactivities. The production of anti-HER2 antibody from the FUT8 gene knockout CHO-S cells in the bioreactor increased by 37% compared to the shake flask system. The N-glycan profile of the produced antibody was consistent between the bioreactor and shake flask system. The antibody-dependent cellular cytotoxicity activity of the defucosylated antibody increased 14-fold compared to the wild-type antibody, which was the same as our previous results. The results of our bioprocess development demonstrated that the engineered cell line could be developed to a biopharmaceutical industrial cell line.


Assuntos
Antineoplásicos Imunológicos/metabolismo , Fucosiltransferases/deficiência , Deleção de Genes , Receptor ErbB-2/antagonistas & inibidores , Animais , Células CHO , Cricetulus , Glicosilação , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/genética
8.
PeerJ ; 12: e17341, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38827281

RESUMO

Phosphorus is one of the lowest elements absorbed and utilized by plants in the soil. SPX domain-containing genes family play an important role in plant response to phosphate deficiency signaling pathway, and related to seed development, disease resistance, absorption and transport of other nutrients. However, there are no reports on the mechanism of SPX domain-containing genes in response to phosphorus deficiency in eggplant. In this study, the whole genome identification and functional analysis of SPX domain-containing genes family in eggplant were carried out. Sixteen eggplant SPX domain-containing genes were identified and divided into four categories. Subcellular localization showed that these proteins were located in different cell compartments, including nucleus and membrane system. The expression patterns of these genes in different tissues as well as under phosphate deficiency with auxin were explored. The results showed that SmSPX1, SmSPX5 and SmSPX12 were highest expressed in roots. SmSPX1, SmSPX4, SmSPX5 and SmSPX14 were significantly induced by phosphate deficiency and may be the key candidate genes in response to phosphate starvation in eggplant. Among them, SmSPX1 and SmSPX5 can be induced by auxin under phosphate deficiency. In conclusion, our study preliminary identified the SPX domain genes in eggplant, and the relationship between SPX domain-containing genes and auxin was first analyzed in response to phosphate deficiency, which will provide theoretical basis for improving the absorption of phosphorus in eggplants through molecular breeding technology.


Assuntos
Regulação da Expressão Gênica de Plantas , Proteínas de Plantas , Solanum melongena , Solanum melongena/genética , Solanum melongena/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Ácidos Indolacéticos/metabolismo , Genoma de Planta/genética , Família Multigênica , Fósforo/metabolismo , Fósforo/deficiência , Genes de Plantas , Fosfatos/metabolismo , Fosfatos/deficiência
9.
PLoS One ; 19(2): e0298207, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38330049

RESUMO

PURPOSE: To compare the ability of diffusion parameters obtained by stretched-exponential and kurtosis models of diffusion-weighted imaging (DWI) to distinguish between patients with primary aldosteronism (PA) and healthy controls (HCs) in renal assessment. MATERIALS AND METHODS: A total of 44 participants (22 patients and 22 HCs) underwent renal MRI with an 11 b-value DWI sequence and a 3 b-value diffusion kurtosis imaging (DKI) sequence from June 2021 to April 2022. Binary logistic regression was used to construct regression models combining different diffusion parameters. Receiver-operating characteristic (ROC) curve analysis and comparisons were used to evaluate the ability of single diffusion parameters and combined diffusion models to distinguish between the two groups. RESULTS: A total of six diffusion parameters (including the cortical anomalous exponent term [α_Cortex], medullary fractional anisotropy [FA_Medulla], cortical FA [FA_Cortex], cortical axial diffusivity [Da_Cortex], medullary mean diffusivity [MD_Medulla] and medullary radial diffusivity [Dr_Medulla]) were included, and 10 regression models were studied. The area under the curve (AUC) of Dr_Medulla was 0.855, comparable to that of FA_Cortex and FA_Medulla and significantly higher than that of α_Cortex, Da_Cortex and MD_Medulla. The AUC of the Model_all parameters was 0.967, comparable to that of Model_FA (0.946) and Model_DKI (0.966) and significantly higher than that of the other models. The sensitivity and specificity of Model_all parameters were 87.2% and 95%, respectively. CONCLUSION: The Model_all parameters, Model_FA and Model_DKI were valid for differentiating between PA patients and HCs with similar differentiation efficacy and were superior to single diffusion parameters and other models.


Assuntos
Imagem de Difusão por Ressonância Magnética , Hiperaldosteronismo , Humanos , Imagem de Difusão por Ressonância Magnética/métodos , Rim/diagnóstico por imagem , Imagem de Tensor de Difusão/métodos , Imageamento por Ressonância Magnética/métodos , Hiperaldosteronismo/diagnóstico por imagem
10.
Abdom Radiol (NY) ; 48(4): 1340-1349, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36745206

RESUMO

PURPOSE: This study used various diffusion-weighted imaging (DWI) models (including monoexponential, biexponential, stretched-exponential and kurtosis models) in renal magnetic resonance imaging (MRI) to compare whether there were differences in each diffusion parameter between patients with primary aldosteronism (PA) and healthy volunteers. MATERIALS AND METHODS: Twenty-two (female:male, 14:8; age, 48 ± 10 years) patients with PA and 22 age- and sex-matched healthy controls (HCs) underwent MRI examinations of the kidneys. The independent-sample t test or the Mann‒Whitney U test was used to detect differences in the diffusion metrics of the kidneys between the two groups. Univariable and multivariable linear regression were applied to analyze the correlations between diffusion parameters and the clinical indicators. RESULTS: The mean diffusivity (MD, p < 0.001) and radial diffusivity (Dr, p < 0.001) values in the medulla were lower in the PA group than in the HC group. The medullary fractional anisotropy (FA, p < 0.001) was higher than that of HCs. The FA (p < 0.001) and axial diffusivity (Da, p < 0.001) values in the cortex were lower in the PA group. The cortical α (anomalous exponent term, p = 0.016) was higher in the PA patients than in the HCs. Linear regression analysis showed that log(plasma aldosterone concentration) and the estimated glomerular filtration rate (eGFR) were correlated with medullary FA. CONCLUSION: The stretched-exponential model (cortical α) and the kurtosis model (FA, MD and Dr in the medulla and FA and Da in the cortex) showed significant differences between PA patients and healthy volunteers and may have potential for noninvasive renal assessment in PA patients.


Assuntos
Imagem de Difusão por Ressonância Magnética , Hiperaldosteronismo , Humanos , Masculino , Feminino , Adulto , Pessoa de Meia-Idade , Imagem de Difusão por Ressonância Magnética/métodos , Rim/diagnóstico por imagem , Imageamento por Ressonância Magnética , Anisotropia , Hiperaldosteronismo/diagnóstico por imagem
11.
Cancer Lett ; 572: 216355, 2023 09 28.
Artigo em Inglês | MEDLINE | ID: mdl-37597651

RESUMO

Chimeric antigen receptor (CAR)-T cell immunotherapy is highly effective against hematological neoplasms. However, owing to tumor variability, low antigen specificity, and impermanent viability of CAR-T cells, their use in the treatment of solid tumors is limited. Here, a novel CAR-T cell targeting B7-H3 and incorporating a 4-1BB costimulatory molecule with STAT3-and STAT5-related activation motifs was constructed using lentivirus transduction. B7-H3, a tumor-associated antigen, and its scFv antibody endowed CAR-T cells with tumor-specific targeting capabilities. Moreover, the integration of the trIL2RB and YRHQ motifs stimulated STAT5 and STAT3 in an antigen-dependent manner, inducing a remarkable increase in the proliferation and survival of CAR-T cells via the activation of the JAK-STAT signaling pathway. Besides, the proportion of less-differentiated T cells increased among BB-trIL2RB-z(YRHQ) CAR-T cells. Moreover, BB-trIL2RB-z(YRHQ) effectively inhibited ovarian cancer (OC) and triple-negative breast cancer (TNBC) in vivo at low doses, without high serum levels of inflammatory cytokines and organ toxicity. Therefore, our study proposes a combination of elements for the construction of superior pluripotent CAR-T cells to provide an effective strategy for the treatment of intractable solid tumors.


Assuntos
Neoplasias Ovarianas , Neoplasias de Mama Triplo Negativas , Humanos , Feminino , Neoplasias de Mama Triplo Negativas/terapia , Fator de Transcrição STAT5 , Neoplasias Ovarianas/terapia , Imunoterapia
12.
Ying Yong Sheng Tai Xue Bao ; 33(10): 2725-2735, 2022 Oct.
Artigo em Zh | MEDLINE | ID: mdl-36384608

RESUMO

To explore whether there is an interaction between melatonin (MT) and calcium (Ca2+) in regulating heat tolerance of plants, we analyzed the response of endogenous MT and Ca2+ to heat stress, and examined the effect of MT and Ca2+ on the reactive oxygen (ROS) accumulation, antioxidant system, and transcripts of heat shock factor (HSF) and heat shock proteins (HSPs) of cucumber seedlings under high temperature stress. Seedlings were foliar sprayed with 100 µmol·L-1 MT, 10 mmol·L-1 CaCl2, 3 mmol·L-1 ethylene glycol tetraacetic acid (EGTA, Ca2+ chelating agent) +100 µmol·L-1 MT, 0.05 mmol·L-1 chlorpromazine (calmodulin antagonist, CPZ) +100 µmol·L-1 MT, 100 µmol·L-1 p-chlorophenylalanine (p-CPA, inhibitor of MT) +10 mmol·L-1 CaCl2 or deionized water (H2O), respectively. The results showed that both endogenous MT and Ca2+ in cucumber seedlings were induced by high temperature stress. The seedlings treated with exogenous MT showed significant increases in the mRNA expression of calmodulin (CaM), calcium-dependent protein kinase (CDPK5), calcineurin B-like protein (CBL3) and CBL interacting protein kinase (CIPK2) compared with the control at normal temperature. The mRNA levels of tryptophane decarboxylase (TDC), 5-hydroxytryptamine-N-acetyltransferase (SNAT) and N-acetyl-5-hydroxytryptamine methyltransferase (ASMT), key genes of MT biosynthesis and endogenous MT content were also induced by Ca2+ in cucumber seedlings. Exogenous MT and CaCl2 alleviated the heat-induced oxidative damage through increasing antioxidant ability, reducing the accumulation of reactive oxygen species (ROS), and upregulating the mRNA abundances of HSF7, HSP70.1 and HSP70.11, as evidenced by mild thermal damage symptoms, lower heat injury index and electrolyte leakage under heat stress. The positive effect of MT-induced antioxidant capacity and mRNA expression of HSPs was removed by adding EGTA and CPZ in stressed seedlings. Similarly, the mitigating role of Ca2+ in the peroxidation damage to high temperature stress was reversed by p-CPA. These results suggested that both MT and Ca2+ could induce heat tolerance of cucumber seedlings, which had crosstalk in the process of heat stress signal transduction.


Assuntos
Cucumis sativus , Melatonina , Cucumis sativus/genética , Melatonina/farmacologia , Cálcio , Antioxidantes/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Calmodulina/genética , Calmodulina/metabolismo , Calmodulina/farmacologia , Ácido Egtázico/farmacologia , Cloreto de Cálcio/metabolismo , Cloreto de Cálcio/farmacologia , Temperatura , Estresse Fisiológico , Plântula/fisiologia , RNA Mensageiro/metabolismo , RNA Mensageiro/farmacologia
13.
Front Plant Sci ; 12: 686545, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34367212

RESUMO

Melatonin (MT) and nitric oxide (NO) are two multifunctional signaling molecules that are involved in the response of plants to abiotic stresses. However, how MT and NO synergize in response to cold stress affecting plants is still not clear. In this study, we found that endogenous MT accumulation under cold stress was positively correlated with cold tolerance in different varieties of cucumber seedlings. The data presented here also provide evidence that endogenous NO is involved in the response to cold stress. About 100 µM MT significantly increased the nitrate reductase (NR) activity, NR-relative messenger RNA (mRNA) expression, and endogenous NO accumulation in cucumber seedlings. However, 75 µM sodium nitroprusside (SNP, a NO donor) showed no significant effect on the relative mRNA expression of tryptophan decarboxylase (TDC), tryptamine-5-hydroxylase (T5H), serotonin-N-acetyltransferase (SNAT), or acetylserotonin O-methyltransferase (ASMT), the key genes for MT synthesis and endogenous MT levels. Compared with H2O treatment, both MT and SNP decreased electrolyte leakage (EL), malondialdehyde (MDA), and reactive oxygen species (ROS) accumulation by activating the antioxidant system and consequently mitigated cold damage in cucumber seedlings. MT and SNP also enhanced photosynthetic carbon assimilation, which was mainly attributed to an increase in the activity and mRNA expression of the key enzymes in the Calvin-Benson cycle. Simultaneously, MT- and SNP-induced photoprotection for both photosystem II (PSII) and photosystem I (PSI) in cucumber seedlings, by stimulating the PsbA (D1) protein repair pathway and ferredoxin-mediated NADP+ photoreduction, respectively. Moreover, exogenous MT and SNP markedly upregulated the expression of chilling response genes, such as inducer of CBF expression (ICE1), C-repeat-binding factor (CBF1), and cold-responsive (COR47). MT-induced cold tolerance was suppressed by 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO, a specific scavenger of NO). However, p-chlorophenylalanine (p-CPA, a MT synthesis inhibitor) did not affect NO-induced cold tolerance. Thus, novel results suggest that NO acts as a downstream signal in the MT-induced plant tolerance to cold stress.

14.
Neuroimage Clin ; 23: 101859, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31150957

RESUMO

Accurate, reliable prediction of risk for Alzheimer's disease (AD) is essential for early, disease-modifying therapeutics. Multimodal MRI, such as structural and diffusion MRI, is likely to contain complementary information of neurodegenerative processes in AD. Here we tested the utility of the multimodal MRI (T1-weighted structure and diffusion MRI), combined with high-throughput brain phenotyping-morphometry and structural connectomics-and machine learning, as a diagnostic tool for AD. We used, firstly, a clinical cohort at a dementia clinic (National Health Insurance Service-Ilsan Hospital [NHIS-IH]; N = 211; 110 AD, 64 mild cognitive impairment [MCI], and 37 cognitively normal with subjective memory complaints [SMC]) to test the diagnostic models; and, secondly, Alzheimer's Disease Neuroimaging Initiative (ADNI)-2 to test the generalizability. Our machine learning models trained on the morphometric and connectome estimates (number of features = 34,646) showed optimal classification accuracy (AD/SMC: 97% accuracy, MCI/SMC: 83% accuracy; AD/MCI: 97% accuracy) in NHIS-IH cohort, outperforming a benchmark model (FLAIR-based white matter hyperintensity volumes). In ADNI-2 data, the combined connectome and morphometry model showed similar or superior accuracies (AD/HC: 96%; MCI/HC: 70%; AD/MCI: 75% accuracy) compared with the CSF biomarker model (t-tau, p-tau, and Amyloid ß, and ratios). In predicting MCI to AD progression in a smaller cohort of ADNI-2 (n = 60), the morphometry model showed similar performance with 69% accuracy compared with CSF biomarker model with 70% accuracy. Our comparisons of the classifiers trained on structural MRI, diffusion MRI, FLAIR, and CSF biomarkers showed the promising utility of the white matter structural connectomes in classifying AD and MCI in addition to the widely used structural MRI-based morphometry, when combined with machine learning.


Assuntos
Doença de Alzheimer/diagnóstico por imagem , Encéfalo/diagnóstico por imagem , Conectoma/métodos , Neuroimagem/métodos , Substância Branca/diagnóstico por imagem , Idoso , Idoso de 80 Anos ou mais , Doença de Alzheimer/patologia , Encéfalo/patologia , Imagem de Difusão por Ressonância Magnética , Feminino , Humanos , Aprendizado de Máquina , Imageamento por Ressonância Magnética/métodos , Masculino , Imagem Multimodal , Prognóstico , Substância Branca/patologia
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