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Climate change significantly affects plant biomass and phenological occurrence time in alpine grasslands of Tibetan Plateau. The changes in phenological periods are closely related to the length of vegetative and reproductive growth periods, which may further affect aboveground biomass accumulation. In this study, based on fixed-point observations of plant biomass and phenology as well as the corresponding climatic data from 1997 to 2020 in the alpine grasslands of Tibetan Plateau, we used statistical methods such as ordinary linear regression and piecewise structural equation model to explore the characteristics of interannual climate change in the study area, the variation trends of plant biomass and phenological periods, and the correlations between biomass and phenological and climatic factors. The results showed that mean annual temperature and annual precipitation in the study area increased significantly from 1997 to 2020, suggesting a clear "warm-wet" trend. Aboveground biomass and relative biomass of Stipa sareptana var. krylovii (the dominant species) decreased significantly. However, absolute and relative biomass of subdominant species (Kobresia humilis) increased significantly, indicating that the dominance of K. humilis increased. The warm-wet climates enhanced aboveground biomass accumulation of K. humilis by extending the period of reproductive growth. Mean annual temperature and annual precipitation decreased aboveground biomass of S. sareptana by shortening the length of vegetative growth period. In a word, the warmer and wetter climate significantly affected aboveground biomass accumulation by regulating the changes in the phenological period, and the interspecific difference in their response resulted in a larger change in community composition. This study area may show a trend from alpine grassland to alpine meadow, and thus further works are urgently needed.
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Biomassa , Mudança Climática , Pradaria , Poaceae , Tibet , Poaceae/crescimento & desenvolvimento , China , Altitude , EcossistemaRESUMO
Alzheimer's disease (AD) is a neurodegenerative illness with a typical age of onset exceeding 65 years of age. The age dependency of the condition led us to track the appearance of DNA damage in the frontal cortex of individuals who died with a diagnosis of AD. The focus on DNA damage was motivated by evidence that increasing levels of irreparable DNA damage are a major driver of the aging process. The connection between aging and the loss of genomic integrity is compelling because DNA damage has also been identified as a possible cause of cellular senescence. The number of senescent cells has been reported to increase with age, and their senescence-associated secreted products are likely contributing factors to age-related illnesses. We tracked DNA damage with 53BP1 and cellular senescence with p16 immunostaining of human post-mortem brain samples. We found that DNA damage was significantly increased in the BA9 region of the AD cortex compared with the same region in unaffected controls (UCs). In the AD but not UC cases, the density of cells with DNA damage increased with distance from the pia mater up to approximately layer V and then decreased in deeper areas. This pattern of DNA damage was overlaid with the pattern of cellular senescence, which also increased with cortical depth. On a cell-by-cell basis, we found that the intensities of the two markers were tightly linked in the AD but not the UC brain. To test whether DNA damage was a causal factor in the emergence of the senescence program, we used etoposide treatment to damage the DNA of cultured mouse primary neurons. While DNA damage increased after treatment, after 24 h, no change in the expression of senescence-associated markers was observed. Our work suggests that DNA damage and cellular senescence are both increased in the AD brain and increasingly coupled. We propose that in vivo, the relationship between the two age-related processes is more complex than previously thought.
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White matter hyperintensity (WMH) is strongly correlated with age-related dementia and hypertension, but its pathogenesis remains obscure. GWAS identified TRIM47 at 17q25 locus as a top genetic risk factor for WMH formation. TRIM family is a class of E3 ubiquitin ligase with pivotal functions in autophagy, which is critical for brain endothelial cell (ECs) remodeling during hypertension. We hypothesize that TRIM47 regulates autophagy and its loss-of-function disturbs cerebrovasculature. Based on transcriptomics and immunohistochemistry, TRIM47 is found selectively expressed by brain ECs in human and mouse, and its transcription is upregulated by artificially-induced autophagy while downregulated in hypertension-like conditions. Using in silico simulation, immunocytochemistry and super-resolution microscopy, we identified the highly conserved binding site between TRIM47 and the LIR (LC3-interacting region) motif of LC3B. Importantly, pharmacological autophagy induction increased Trim47 expression on mouse ECs (b.End3) culture, while silencing Trim47 significantly increased autophagy with ULK1 phosphorylation induction, transcription and vacuole formation. Together, we confirm that TRIM47 is an endogenous inhibitor of autophagy in brain ECs, and such TRIM47-mediated regulation connects genetic and physiological risk factors for WMH formation but warrants further investigation. SUMMARY STATEMENT: TRIM47, top genetic risk factor for white matter hyperintensity formation, is a negative regulator of autophagy in brain endothelial cells and implicates a novel cellular mechanism for age-related cerebrovascular changes.
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The amyloid precursor protein (APP) is linked to the genetics and pathogenesis of Alzheimer's disease (AD). It is the parent protein of the ß-amyloid (Aß) peptide, the main constituent of the amyloid plaques found in an AD brain. The pathways from APP to Aß are intensively studied, yet the normal functions of APP itself have generated less interest. We report here that glutamate stimulation of neuronal activity leads to a rapid increase in App gene expression. In mouse and human neurons, elevated APP protein changes the structure of the axon initial segment (AIS) where action potentials are initiated. The AIS is shortened in length and shifts away from the cell body. The GCaMP8f Ca2+ reporter confirms the predicted decrease in neuronal activity. NMDA antagonists or knockdown of App block the glutamate effects. The actions of APP on the AIS are cell-autonomous; exogenous Aß, either fibrillar or oligomeric, has no effect. In culture, APPSwe (a familial AD mutation) induces larger AIS changes than wild type APP. Ankyrin G and ßIV-spectrin, scaffolding proteins of the AIS, both physically associate with APP, more so in AD brains. Finally, in humans with sporadic AD or in the R1.40 AD mouse model, both females and males, neurons have elevated levels of APP protein that invade the AIS. In vivo as in vitro, this increased APP is associated with a significant shortening of the AIS. The findings outline a new role for the APP and encourage a reconsideration of its relationship to AD.SIGNIFICANCE STATEMENT While the amyloid precursor protein (APP) has long been associated with Alzheimer's disease (AD), the normal functions of the full-length Type I membrane protein have been largely unexplored. We report here that the levels of APP protein increase with neuronal activity. In vivo and in vitro, modest amounts of excess APP alter the properties of the axon initial segment. The ß-amyloid peptide derived from APP is without effect. Consistent with the observed changes in the axon initial segment which would be expected to decrease action potential firing, we show that APP expression depresses neuronal activity. In mouse AD models and human sporadic AD, APP physically associates with the scaffolding proteins of the axon initial segment, suggesting a relationship with AD dementia.
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Doença de Alzheimer , Segmento Inicial do Axônio , Masculino , Feminino , Camundongos , Humanos , Animais , Precursor de Proteína beta-Amiloide/genética , Precursor de Proteína beta-Amiloide/metabolismo , Doença de Alzheimer/metabolismo , Segmento Inicial do Axônio/metabolismo , Peptídeos beta-Amiloides/metabolismo , Proteínas de Membrana , Camundongos Transgênicos , Modelos Animais de DoençasRESUMO
Lycium barbarum polysaccharide (LBP) as one of the main bioactive constituents of the fruit of Lycium barbarum L. (LBL.) has many pharmacological activities, but its antihyperglycemic activity is not fully understood yet. This study investigated the hypoglycemic and renal protective effects of LBP on high-fat diet/streptozotocin- (HFD/STZ-) induced diabetic nephropathy (DN) in mice. Blood glucose was assessed before and after 8-week administration of LBP, and the homeostasis model assessment-insulin resistance (HOMA-IR) index was calculated for evaluating the antidiabetic effect of LBP. Additionally, serum creatinine (sCr), blood urea nitrogen (BUN), and urine microalbumin were tested to evaluate the renal function. HE and PAS stainings were performed to evaluate the morphology and injury of the kidney. The results showed that LBP significantly reduces the glucose level and ameliorates the insulin resistance of diabetic mice. Importantly, LBP improves renal function by lowering the levels of sCr, BUN, and microalbumin in diabetic mice and relieves the injury in the renal glomeruli and tubules of the DN mice. Furthermore, LBP attenuates renal inflammation as evidenced by downregulating the mRNA levels of TNFα, IL1 ß, IL6, and SAA3 in the renal cortex, as well as reducing the elevated circulating level and protein depositions of SAA3 in the kidney. In addition, our western blot results showed that NF-κB p65 nuclear translocation and the degradation of inhibitory κB-α (IκBα) occurred during the progress of inflammation, and such activated signaling was restrained by LBP. In conclusion, our findings suggest that LBP is a potential antidiabetic agent, which ameliorates the inflammation in DN through inhibiting NF-κB activation.
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Diabetes Mellitus Experimental , Nefropatias Diabéticas , Medicamentos de Ervas Chinesas , Animais , Diabetes Mellitus Experimental/complicações , Diabetes Mellitus Experimental/tratamento farmacológico , Nefropatias Diabéticas/tratamento farmacológico , Medicamentos de Ervas Chinesas/farmacologia , Medicamentos de Ervas Chinesas/uso terapêutico , Camundongos , NF-kappa B/metabolismoRESUMO
Adult-onset neurodegenerative diseases are often accompanied by evidence of a chronic inflammation that includes activation of microglial cells and altered levels of brain cytokines. Aspects of this response are likely secondary reactions to neurodegeneration, but for many illnesses the inflammation may itself be an early and even causative disease event. In such cases, the inflammation is referred to as "sterile" as it occurs in the absence of an actual bacterial or viral pathogen. A potent trigger of sterile inflammation in CNS microglia has been shown to be the presence of DNA in the cytoplasm (cytoDNA) induced either by direct DNA damage or by inhibited DNA repair. We have shown that cytoDNA comes from the cell nucleus as a result of insufficient DNA damage repair. Using wild-type and Atm-/- mouse microglia, we extend these observations here by showing that its genomic origins are not random, but rather are heavily biased toward transcriptionally inactive, intergenic regions, in particular repetitive elements and AT-rich sequences. Once released from the genome, in both males and females, we show that cytoDNA is actively exported to the cytoplasm by a CRM1-dependent mechanism. In the cytoplasm, it is degraded either by a cytosolic exonuclease, Trex1, or an autophagy pathway that ends with degradation in the lysosome. Blocking the accumulation of cytoDNA prevents the emergence of the sterile inflammation reaction. These findings offer new insights into the emergence of sterile inflammation and offer novel approaches that may be of use in combatting a wide range of neurodegenerative conditions.SIGNIFICANCE STATEMENT Sterile inflammation describes a state where the defenses of the immune system are activated in the absence of a true pathogen. A potent trigger of this unorthodox response is the presence of DNA in the cytoplasm, which immune cells interpret as an invading virus or pathogen. We show that when DNA damage increases, fragments of the cell's own genome are actively exported to the cytoplasm where they are normally degraded. If this degradation is incomplete an immune reaction is triggered. Both age and stress increase DNA damage, and as age-related neurodegenerative diseases are frequently accompanied by a chronic low-level inflammation, strategies that reduce the induction of cytoplasmic DNA or speed its clearance become attractive therapeutic targets.
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Citoplasma/imunologia , Dano ao DNA/imunologia , DNA/imunologia , Inflamação/imunologia , Sequências Repetitivas de Ácido Nucleico/imunologia , Animais , Citoplasma/metabolismo , DNA/metabolismo , Reparo do DNA , Feminino , Inflamação/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Microglia/imunologia , Microglia/metabolismoRESUMO
Pancreatic duct adenocarcinoma (PDAC) is an aggressive and lethal malignancy. Pancreatic cancer stem cells (PCSCs) are assumed to contribute to the initiation and invasion of PDAC. In this study, we performed single-cell RNA sequencing (scRNA-seq) analysis of PDAC tumor samples from patients and control pancreas tissues to reveal the transformation process of cancer stem cell (CSC)-like ductal cells into ductal cells with invasive potential and we screened out CSC-related genes (CRGs). Subsequently, we applied LASSO and Cox regression models to identify five CRGs with potential prognostic values and constructed a risk prognostic model using the Cancer Genome Atlas datasets. The risk models were verified using Gene Expression Omnibus datasets. Patients in the high-risk group had a significantly poor overall survival (Pvalue<0.0001), as illustrated by the Kaplan-Meier survival curve, and the area under the curve confirmed the accuracy of predictions by our risk model. Tumor mutation burden variations were used to further explore the differences between the two risk cohorts. In addition, the Human Protein Atlas was used to investigate the protein expression of five hub CRGs. In brief, we utilized scRNA-seq to reveal the invasive trajectory of ductal cells and identified crucial CRGs in PDAC, which may help predict patient survival and provide potential clinical therapeutic targets against CSCs.
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Carcinoma Ductal Pancreático , Células-Tronco Neoplásicas/metabolismo , Neoplasias Pancreáticas , Transcriptoma/genética , Biomarcadores Tumorais/genética , Carcinoma Ductal Pancreático/diagnóstico , Carcinoma Ductal Pancreático/genética , Carcinoma Ductal Pancreático/metabolismo , Carcinoma Ductal Pancreático/mortalidade , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Pâncreas/metabolismo , Neoplasias Pancreáticas/diagnóstico , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/metabolismo , Neoplasias Pancreáticas/mortalidade , Prognóstico , RNA-Seq , Análise de Célula ÚnicaRESUMO
Experiments in primary culture have helped advance our understanding of the curious phenomenon of cell cycle-related neuronal death. In a differentiated postmitotic cell such as a neuron, aberrant cell cycle reentry is strongly associated with apoptosis. Indeed, in many pathologic conditions, neuronal populations at risk for death are marked by cells engaged in a cell cycle like process. The evidence for this conclusion is typically based on finding MAP2+ cells that are also positive for cell cycle-related proteins (e.g., cyclin D) or have incorporated thymidine analogs such as bromodeoxyuridine (BrdU) or 5-ethynyl-2'-deoxyuridine (EdU) into their nuclei. We now report that we and others may have partly been led astray in pursuing this line of work. Morphometric analysis of mouse embryonic cortical cultures reveals that the size of the "cycling" MAP2+ cells is significantly smaller than those of normal neurons, and their expression of MAP2 is significantly lower. This led us to ask whether, rather than representing fully developed neurons, they more closely resembled precursor-like cells. In support of this idea, we find that these small MAP2+ cells are immunopositive for nestin, a neuronal precursor marker, Olig2, an oligodendrocyte lineage marker, and neural/glial antigen 2 (NG2), an oligodendrocyte precursor marker. Tracking their behavior in culture, we find that they predominantly give rise to GFAP+ astrocytes instead of neurons or oligodendrocytes. These findings argue for a critical reexamination of previous reports of stimuli that lead to neuronal cell cycle-related death in primary cultures.
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Neuroglia , Células-Tronco , Animais , Astrócitos , Diferenciação Celular , Camundongos , NeurôniosRESUMO
ATM (ataxia telangiectasia mutated) protein is found associated with multiple organelles including synaptic vesicles, endosomes and lysosomes, often in cooperation with ATR (ataxia telangiectasia and Rad3 related). Mutation of the ATM gene results in ataxia-telangiectasia (A-T), an autosomal recessive disorder with defects in multiple organs including the nervous system. Precisely how ATM deficiency leads to the complex phenotypes of A-T, however, remains elusive. Here, we reported that part of the connection may lie in autophagy and lysosomal abnormalities. We found that ATM was degraded through the autophagy pathway, while ATR was processed by the proteasome. Autophagy and lysosomal trafficking were both abnormal in atm-/- neurons and the deficits impacted cellular functions such as synapse maintenance, neuronal survival and glucose uptake. Upregulated autophagic flux was observed in atm-/- lysosomes, associated with a more acidic pH. Significantly, we found that the ATP6V1A (ATPase, H+ transporting, lysosomal V1 subunit A) proton pump was an ATM kinase target. In atm-/- neurons, lysosomes showed enhanced retrograde transport and accumulated in the perinuclear regions. We attributed this change to an unexpected physical interaction between ATM and the retrograde transport motor protein, dynein. As a consequence, SLC2A4/GLUT4 (solute carrier family 4 [facilitated glucose transporter], member 4) translocation to the plasma membrane was inhibited and trafficking to the lysosomes was increased, leading to impaired glucose uptake capacity. Together, these data underscored the involvement of ATM in a variety of neuronal vesicular trafficking processes, offering new and therapeutically useful insights into the pathogenesis of A-T.Abbreviations: 3-MA: 3-methyladenine; A-T: ataxia-telangiectasia; ALG2: asparagine-linked glycosylation 2 (alpha-1,3-mannosyltransferase); AMPK: adenosine 5'-monophosphate (AMP)-activated protein kinase; ATG5: autophagy related 5; ATM: ataxia telangiectasia mutated; ATP6V1A: ATPase, H+ transporting, lysosomal V1 subunit A; ATR: ataxia-telangiectasia and Rad3 related; BFA1: bafilomycin A1; CC3: cleaved-CASP3; CGN: cerebellar granule neuron; CLQ: chloroquine; CN: neocortical neuron; CTSB: cathepsin B; CTSD: cathepsin D; DYNLL1: the light chain1 of dynein; EIF4EBP1/4E-BP1: eukaryotic translation initiation factor 4E binding protein 1; Etop: etoposide; FBS: fetal bovine serum; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; HBS: HEPES-buffered saline; HEPES: 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid; HOMER1: homer protein homolog 1; KU: KU-60019; LAMP1: lysosomal-associated membrane protein 1; LC3B-II: LC3-phosphatidylethanolamine conjugate; Lyso: lysosome; LysopH-GFP: lysopHluorin-GFP; MAP1LC3B/LC3B: microtubule-associated protein 1 light chain 3 beta; MAP2: microtubule associated protein 2; MAPK14: mitogen-activated protein kinase 14; MAPK8/JNK1: mitogen-activated protein kinase 8; MCOLN1/TRPML1: mucolipin 1; OSBPL1A: oxysterol binding protein like 1A; PIKK: phosphatidylinositol 3 kinase related kinase; Rapa: rapamycin; RILP: rab interacting lysosomal protein; ROS: reactive oxygen species; SEM: standard error of mean; SLC2A4/GLUT4: solute carrier family 2 (facilitated glucose transporter), member 4; TSC2/tuberin: TSC complex subunit 2; ULK1: unc-51 like kinase 1; UPS: ubiquitin-proteasome system; VE: VE-822; WCL: whole-cell lysate; WT: wild type.
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Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Autofagia/genética , Lisossomos/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Animais , Proteínas Mutadas de Ataxia Telangiectasia/genética , Autofagossomos/metabolismo , Autofagia/fisiologia , Humanos , Lisossomos/metabolismo , Camundongos , Fagocitose/genética , Fagocitose/fisiologia , Ubiquitina/metabolismoRESUMO
Pancreatic cancer has a low survival rate globally. Anillin (ANLN) is involved in the pathogenesis of pancreatic cancer (PC). The present study used databases and reverse transcription-quantitative PCR to investigate the association between ANLN expression, clinical variables and the survival rate of patients with pancreatic cancer. Gene expression of ANLN in normal and cancer tissues was analyzed using data from The Cancer Genome Atlas, Oncomine and Gene Expression database of Normal and Tumor tissues 2 and ANOVA, and the association between ANLN mRNA expression and ANLN genovariation was analyzed using cBioPortal. The association between ANLN expression and the survival, clinical, pathological and prognostic characteristics of PC was analyzed using Kaplan-Meier (K-M) survival analysis, Kruskal Wallis and Mann Whitney-U tests, and logistic and Cox regression models. Gene Set Enrichment Analysis (GSEA) revealed the molecular pathways underpinning ANLN function in PC. Overexpression of ANLN was observed in PC cells (normal vs. tumor, P<0.01) and tissues (normal vs. tumor, P=0.008). Enhanced ANLN expression was associated with high tumor grade (grade 1 vs. grade 3, odds ratio: 5.662, P<0.001). However, ANLN expression was not associated with other clinical features (all P>0.05). K-M analysis suggested that increased ANLN expression was associated with poor survival (P=0.002). Univariate and multivariate analysis revealed the ANLN is an independent prognostic factor for PC (P<0.001). GSEA demonstrated the p53, cell cycle, DNA replication, mismatch repair, nucleotide excision repair and PC pathways were associated with low expression of ANLN. Overall, ANLN is more highly expressed in PC compared with in normal tissue, and is associated with poor differentiation. The expression of ANLN may be a novel prognostic marker of poor survival. Finally, ANLN exert its functions in PC through the p53, cell cycle, DNA replication, mismatch repair and nucleotide excision repair and pathways.
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OBJECTIVE: To evaluate Roux-en-Y and Billroth II reconstruction following pancreaticoduodenectomy (PD). METHODS: PubMed, Embase, the Cochrane Library, and the Web of Science were searched to identify randomized controlled trials (RCTs) and controlled clinical trials that compared Roux-en-Y and Billroth II reconstruction following PD up to December 2019. RevMan 5.3 software was used for the statistical analysis. RESULTS: Four RCTs and five controlled clinical trials were included, with a total of 1,072 patients (500 and 572 patients in the Roux-en-Y and Billroth II groups, respectively). No significant differences in delayed gastric emptying (DGE), A-grade DGE, B-grade DGE, or C-grade DGE were observed between the Roux-en-Y and Billroth II reconstruction groups after PD (odds ratio [OR] = 1.01, 95% confidence interval [CI]: 0.50-2.03, P = 0.98; OR = 0.49, 95% CI: 0.17-1.45, P = 0.20; OR = 0.63, 95% CI: 0.29-1.38, P = 0.25; and OR = 2.13, 95% CI: 0.38-11.99, P = 0.39). No significant difference in the incidence of postoperative pancreatic fistula, abscess, bile leaks, infection, postoperative bleeding, or the length of the postoperative hospital stay was observed between the Roux-en-Y and Billroth II groups (P > 0.05), but the operation time was significantly different (mean difference [MD] = 31.65, 95% CI: 7.14-56.17, P = 0.01). CONCLUSIONS: Billroth II reconstruction after PD did not significantly reduce the incidence of DGE or other complications but shortened the operation time compared to Roux-en-Y reconstruction. However, the results must be verified by further high-quality, large RCTs or controlled clinical trials.
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Anastomose em-Y de Roux/efeitos adversos , Anastomose em-Y de Roux/métodos , Pancreaticoduodenectomia/efeitos adversos , Pancreaticoduodenectomia/métodos , Anastomose Cirúrgica/efeitos adversos , Gastrectomia/efeitos adversos , Esvaziamento Gástrico , Hemorragia , Humanos , Tempo de Internação , Duração da Cirurgia , Fístula Pancreática/etiologia , Complicações Pós-Operatórias , Período Pós-Operatório , Ensaios Clínicos Controlados Aleatórios como Assunto , Fatores de Risco , Resultado do TratamentoRESUMO
BACKGROUND: Gastric cancer is a malignant tumor originating from the gastric mucosal epithelium, ranking fourth in the incidence of male malignant tumors and third in mortality rate. The aim of this study is to investigate the efficacy and adverse reactions of DCF and FOLFOXs regimens in the treatment of advanced gastric cancer. METHODS: Relevant prospective clinical controlled studies were retrieved from WanFang Data, CBM, CNKI, PubMed, The Cochrane Library and Embase databases and meta-analysis was performed using RevMan 5.3 software. RESULTS: The effective rates of DCF group and FOLFOXs group were basically the same (RR 1.06, 95% CI: 0.92-1.23, P=0.41). The incidence of nausea and vomiting (RR 1.36, 95% CI: 1.15-1.60), anemia (RR 2.04, 95% CI: 1.55-2.68), thrombocytopenia (RR 1.52, 95% CI: 1.15-2.01) and leukopenia (RR 1.70, 95% CI: 1.44-2.01) with FOLFOXs regimen were significantly lower than DCF regimen, while the incidence of sensory neurotoxicity was significantly higher than DCF regimen (RR 0.53, 95% CI: 0.38-0.74). There were no significant differences in efficacy, ORR and DCR between different doses in the FOLFOXs group (P=0.233). CONCLUSIONS: The efficacy of FOLFOXs regimen was comparable to that of DCF regimen in the treatment of advanced gastric cancer, but the incidence of adverse reactions was significantly lower, and there were no significant differences between different therapeutic doses.
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The study investigated the efficacy of two GRAS-status phytochemicals, mega-resveratrol (RV) and naringenin (NG) to inactivate Escherichia coli O157:H7 (EHEC) in apple cider. A five-strain mixture of EHEC (â¼7 log CFU/ml) was inoculated into cider, followed by the addition of RV (8.7â¯mM and 13.0â¯mM) or NG (7.3â¯mM and 11.0â¯mM). The cider samples were stored at 4⯰C for 14 days and EHEC was enumerated on days 0,1,5,7 and 14. The deleterious effects of RV and NG on EHEC cells were visualized by scanning electron microscopy (SEM), and RT-qPCR was done to determine the effect of phytochemicals on three known acid resistance (AR) systems of EHEC. NG was more effective than RV and reduced EHEC counts by â¼4.5 log CFU/ml by day 14, whereas RV reduced counts by â¼2.5 log CFU/ml compared to controls (Pâ¯<â¯0.05). SEM showed that RV and NG resulted in the destruction of EHEC cells, and surviving bacteria appeared 'lemon shaped'. RT-qPCR results revealed that RV and NG downregulated the transcription of AR associated genes in EHEC (Pâ¯<â¯0.05). Results suggest the potential use of RV and NG as natural antimicrobial additives to enhance the microbiological safety of apple cider. However, sensory analysis studies are warranted.
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Escherichia coli O157/efeitos dos fármacos , Flavanonas/farmacologia , Aditivos Alimentares/farmacologia , Conservação de Alimentos/métodos , Sucos de Frutas e Vegetais/microbiologia , Malus/microbiologia , Resveratrol/farmacologia , Escherichia coli O157/crescimento & desenvolvimento , Malus/química , Viabilidade Microbiana/efeitos dos fármacosRESUMO
ATM (ataxia-telangiectasia mutated) is a PI3K-like kinase best known for its role in the DNA damage response (DDR), especially after double-strand breaks. Mutations in the ATM gene result in a condition known as ataxia-telangiectasia (A-T) that is characterized by cancer predisposition, radiosensitivity, neurodegeneration, sterility, and acquired immune deficiency. We show here that the innate immune system is not spared in A-T. ATM-deficient microglia adopt an active phenotype that includes the overproduction of proinflammatory cytokines that are toxic to cultured neurons and likely contribute to A-T neurodegeneration. Causatively, ATM dysfunction results in the accumulation of DNA in the cytoplasm of microglia as well as a variety of other cell types. In microglia, cytoplasmic DNA primes an antiviral response via the DNA sensor, STING (stimulator of interferon genes). The importance of this response pathway is supported by our finding that inhibition of STING blocks the overproduction of neurotoxic cytokines. Cytosolic DNA also activates the AIM2 (absent in melanoma 2) containing inflammasome and induces proteolytic processing of cytokine precursors such as pro-IL-1ß. Our study furthers our understanding of neurodegeneration in A-T and highlights the role of cytosolic DNA in the innate immune response.SIGNIFICANCE STATEMENT Conventionally, the immune deficiencies found in ataxia-telangiectasia (A-T) patients are viewed as defects of the B and T cells of the acquired immune system. In this study, we demonstrate the microglia of the innate immune system are also affected and uncover the mechanism by which this occurs. Loss of ATM (ataxia-telangiectasia mutated) activity leads to a slowing of DNA repair and an accumulation of cytoplasmic fragments of genomic DNA. This ectopic DNA induces the antivirus response, which triggers the production of neurotoxic cytokines. This expands our understanding of the neurodegeneration found in A-T and offers potentially new therapeutic options.
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Citocinas/biossíntese , Dano ao DNA , DNA/metabolismo , Inflamassomos/metabolismo , Microglia/fisiologia , Animais , Apoptose , Ataxia Telangiectasia/genética , Ataxia Telangiectasia/imunologia , Proteínas Mutadas de Ataxia Telangiectasia/antagonistas & inibidores , Proteínas Mutadas de Ataxia Telangiectasia/deficiência , Proteínas Mutadas de Ataxia Telangiectasia/fisiologia , Células Cultivadas , Córtex Cerebral/citologia , Córtex Cerebral/embriologia , Meios de Cultivo Condicionados/farmacologia , Citocinas/genética , Citoplasma/metabolismo , Proteínas de Ligação a DNA/fisiologia , Feminino , Fibroblastos , Humanos , Imunidade Inata , Masculino , Proteínas de Membrana/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Morfolinas/farmacologia , Doenças Neurodegenerativas/genética , Doenças Neurodegenerativas/metabolismo , Tioxantenos/farmacologia , TranscriptomaRESUMO
BACKGROUND: Inflammation plays a critical role in accelerating the progression of neurodegenerative diseases, such as Alzheimer's disease (AD) and ataxia telangiectasia (A-T). In A-T mouse models, LPS-induced neuroinflammation advances the degenerative changes found in cerebellar Purkinje neurons both in vivo and in vitro. In the current study, we ask whether ibuprofen, a non-steroidal anti-inflammatory drug (NSAID), can have the opposite effect and delay the symptoms of the disease. METHODS: We tested the beneficial effects of ibuprofen in both in vitro and in vivo models. Conditioned medium from LPS stimulated primary microglia (LM) applied to cultures of dissociated cortical neurons leads to numerous degenerative changes. Pretreatment of the neurons with ibuprofen, however, blocked this damage. Systemic injection of LPS into either adult wild-type or adult Atm-/- mice produced an immune challenge that triggered profound behavioral, biochemical, and histological effects. We used a 2-week ibuprofen pretreatment regimen to investigate whether these LPS effects could be blocked. We also treated young presymptomatic Atm-/- mice to determine if ibuprofen could delay the appearance of symptoms. RESULTS: Adding ibuprofen directly to neuronal cultures significantly reduced LM-induced degeneration. Curiously, adding ibuprofen to the microglia cultures before the LPS challenge had little effect, thus implying a direct effect of the NSAID on the neuronal cultures. In vivo administration of ibuprofen to Atm-/- animals before a systemic LPS immune challenge suppressed cytological damage. The ibuprofen effects were widespread as microglial activation, p38 phosphorylation, DNA damage, and neuronal cell cycle reentry were all reduced. Unfortunately, ibuprofen only slightly improved the LPS-induced behavioral deficits. Yet, while the behavioral symptoms could not be reversed once they were established in adult Atm-/- animals, administration of ibuprofen to young mutant pups prevented their symptoms from appearing. CONCLUSION: Inflammatory processes impact the normal progression of A-T implying that modulation of the immune system can have therapeutic benefit for both the behavioral and cellular symptoms of this neurodegenerative disease.
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Ataxia Telangiectasia/prevenção & controle , Ibuprofeno/farmacologia , Animais , Animais Recém-Nascidos , Anti-Inflamatórios não Esteroides/farmacologia , Ataxia Telangiectasia/induzido quimicamente , Ataxia Telangiectasia/fisiopatologia , Proteínas Mutadas de Ataxia Telangiectasia/deficiência , Proteínas Mutadas de Ataxia Telangiectasia/genética , Células Cultivadas , Citocinas/genética , Citocinas/metabolismo , Modelos Animais de Doenças , Comportamento Exploratório/efeitos dos fármacos , Feminino , Regulação da Expressão Gênica/efeitos dos fármacos , Regulação da Expressão Gênica/genética , Gliceraldeído-3-Fosfato Desidrogenase (Fosforiladora)/metabolismo , Lipopolissacarídeos/toxicidade , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Neuroglia/efeitos dos fármacos , Neuroglia/metabolismo , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genéticaRESUMO
INTRODUCTION: In looking for novel non-amyloid-based etiologies for Alzheimer's disease, we explore the hypothesis that age-related myelin loss is an attractive explanation for age-associated cognitive decline and dementia. METHODS: We performed a meta-analysis of data in the National Alzheimer's Coordinating Center database accompanied by quantitative histopathology of myelin and oligodendrocytes (OLs) in frontal cortices of 24 clinically characterized individuals. Pathological findings were further validated in an Alzheimer's disease mouse model and in culture. RESULTS: Myelin lesions increased with cognitive impairment in an amyloid-independent fashion with signs of degeneration appearing before neuronal loss. Myelinating OLs in the gray matter showed greater vulnerability than those in white matter, and the degenerative changes correlated with evidence of DNA damage. Similar results were found in myelinating OL cultures where DNA damage caused aberrant OL cell cycle re-entry and death. DISCUSSION: We present the first comprehensive analysis of the cell biology of early myelin loss in sporadic Alzheimer's disease.
Assuntos
Dano ao DNA , Demência/patologia , Oligodendroglia/patologia , Placa Amiloide/patologia , Substância Branca/patologia , Idoso , Animais , Estudos Transversais , Modelos Animais de Doenças , Lobo Frontal/metabolismo , Humanos , Metanálise como Assunto , Camundongos Transgênicos , Pessoa de Meia-IdadeRESUMO
Escherichia coli O157: H7 (EHEC) is a major foodborne pathogen largely transmitted to humans through the consumption of undercooked ground beef. This study investigated the efficacy of two food-grade, plant-derived antimicrobials, namely rutin (RT), and resveratrol (RV) with or without chitosan (CH) in enhancing EHEC inactivation in undercooked hamburger patties. Further, the effect of aforementioned treatments on beef color and lipid oxidation was analyzed. Additionally, the deleterious effects of these antimicrobial treatments on EHEC was determined using scanning electron microscopy (SEM). Ground beef was inoculated with a five-strain mixture of EHEC (7.0 log CFU/g), followed by the addition of RT (0.05%, 0.1% w/w) or RV (0.1, 0.2% w/w) with or without CH (0.01% w/w). The meat was formed into patties (25 g) and stored at 4°C for 5 days. On days 1, 3, and 5, the patties were cooked (65°C, medium rare) and surviving EHEC was enumerated. The effect of these treatments on meat color and lipid oxidation during storage was also determined as per American Meat Science Association guidelines. The study was repeated three times with duplicate samples of each treatment. Both RT and RV enhanced the thermal destruction of EHEC, and reduced the pathogen load by at least 3 log CFU/g compared to control (P < 0.05). The combination of RT or RV with CH was found to be more effective, and reduced EHEC by 5 log CFU/g (P < 0.05). EHEC counts in uncooked patties did not decline during storage for 5 days (P > 0.05). Moreover, patties treated with RV plus CH were more color stable with higher a(∗) values (P < 0.05). SEM results revealed that heat treatment with antimicrobials (CH + RV 0.2%) resulted in complete destruction of EHEC cells and extrusion of intracellular contents. Results suggest that the aforementioned antimicrobials could be used for enhancing the thermal inactivation of EHEC in undercooked patties; however, detailed sensory studies are warranted.