Effect of Age, Comedications, and CYP3A4/5 Polymorphisms on Perampanel Exposure in Chinese Pediatric Patients With Epilepsy.

Perampanel (PER) is a new type of antiseizure medication used for partial or generalized seizures. However, the plasma concentration shows obvious individual variability in children. The present study aims to ascertain the effect of age, comedications, and cytochrome P450 (CYP) 3A4/5 polymorphisms on PER exposure in Chinese pediatric patients with epilepsy. Clinical data were retrospectively collected in a tertiary children's hospital medical records system from January 2021 to December 2022. The influence factors on the daily dose, plasma concentration, and concentration-to-dose ratio (CDR) of PER were investigated. A total of 135 pediatric patients with 178 blood samples were involved. With a median daily dose of 4.0 mg (interquartile range, 3.0-5.0 mg), the median plasma concentration was 409.4 ng/mL (interquartile range, 251.7-639.4 ng/mL). The CDR in patients aged less than 4 years was significantly decreased by 48.0% and 39.1% compared with those aged 4-11 years and 12 years or older, respectively. Enzyme inducers significantly decreased the CDR of PER by 34.5%, while valproic acid showed an increase of 71.7%. In addition, genotype CYP3A5*3/*3 carriers presented a significant increase of 21.5% compared to the CYP3A5*1/*3 expresser. No correlations were observed between the CDR and CYP3A4∗1G polymorphism. PER showed high variations in individual plasma concentrations. Age younger than 4 years, comedication with enzyme inducers or valproic acid, and possession of the CYP3A5*3 genotype potentially predicted PER exposure in pediatric patients with epilepsy.

Endothelial TFEB signaling-mediated autophagic disturbance initiates microglial activation and cognitive dysfunction.

Cognitive impairment caused by systemic chemotherapy is a critical question that perplexes the effective implementation of clinical treatment, but related molecular events are poorly understood. Herein, we show that bortezomib exposure leads to microglia activation and cognitive impairment, this occurs along with decreased nuclear translocation of TFEB (transcription factor EB), which is linked to macroautophagy/autophagy disorder, STAT3 (signal transducer and activator of transcription 3) phosphorylation and IL23A (interleukin 23 subunit alpha) expression. Pharmacological enhancement of TFEB nuclear translocation by digoxin restores lysosomal function and reduces STAT3-dependent endothelial IL23A secretion. As a consequence, we found that brain endothelial-specific ablation of Il23a ameliorated both microglia activation and cognitive dysfunction. Thus, the endothelial TFEB-STAT3-IL23A axis in the brain represents a critical cellular event for initiating bortezomib-mediated aberrant microglial activation and synapse engulfment. Our results suggest the reversal of TFEB nuclear translocation may provide a novel therapeutic approach to prevent symptoms of cognitive dysfunction during clinical use of bortezomib.Abbreviations: AAV: adeno-associated virus; BBB: blood-brain barrier; BTZ: bortezomib; DG: digoxin; DGs: dentate gyrus; DLG4/PSD95: discs large MAGUK scaffold protein 4; HBMECs: human brain microvascular endothelial cells; HP: hippocampus; IL23A: interleukin 23 subunit alpha; MBVECs: mouse brain vascular endothelial cells; mPFC: medial prefrontal cortex; NORT: novel object recognition test; OLT: object location test; PLX5622: 6-fluoro-N-([5-fluoro-2-methoxypyridin-3-yl]methyl)-5-(5-methyl-1H-pyrrolo[2,3-b]pyridin-3- yl)methyl; PPP3/calcineurin: protein phosphatase 3; SBEs: STAT3 binding elements; shRNA: small hairpin RNA; SLC17A7/VGLUT1: solute carrier family 17 member 7; SLC32A1/VGAT: solute carrier family 32 member 1; STAT3: signal transducer and activator of transcription 3, TFEB: transcription factor EB; Ub: ubiquitin.

Agro-pastoralists' perception of climate change and adaptation in the Qilian Mountains of northwest China.

Global climate change affects all aspects of human society, especially agricultural and animal husbandry production. Northwest China has been detrimentally affected by the climatic variations due to its high exposure to extreme climatic events. A number of studies have reported agro-pastoralists' perceptions and adaptation responses to climate change, but the current knowledge of agro-pastoralists' perceptions of climate change in China are insufficient. To fill this research gap, this study aims to investigate the perception level of agro-pastoralists in Northwest China on climate change and related factors. Data were collected using a structured questionnaire based on household surveys of 554 study participants in four counties in Gansu Province, China. Raw data were collected using stratified random sampling. A probit model was used to analyze the respondents' understanding of climate change and its related socio-economic and demographic variables. Our results show that the majority of respondents were aware (70%) of the changes in temperature and precipitation. Socioeconomic and demographic variables such as gender, farming experience, education level, cultivated land size, agricultural income, livestock, village cadre experience, access to weather information of agro-pastoralists are pertinently related to agro-pastoralists' awareness of climate change. Farming experience, education level, household size, grassland size, agricultural income, association membership, village cadre experience has a high impact on agro-pastoralists' adaptation to climate change. The results of this study will help guide government agencies and decision makers, and help arid and semi-arid areas to build sustainable adaptation measures under the framework of climate change. The study recommends institutions targeting households' livelihood improvement and making decisions concerning climate change adaptation need to focus on mass media and information technology, improving locally adapted extension services, improved irrigation, expand loan channels.

A point-of-care microfluidic channel-based device for rapid and direct detection of fibrinogen in whole blood.

Hemorrhage is the leading cause of preventable death in civilian and battlefield traumatic injuries. Patients with severe traumatic hemorrhagic shock are more likely to be deficient in fibrinogen than those with other coagulation factors, and hypofibrinogenemia is an independent risk factor for mortality. Thus, rapid detection of fibrinogen levels is of great importance in these patients during damage control resuscitation. Plasma is used as an analyte in fibrinogen detection, which restricts the use of existing devices in emergencies. To meet the needs of on-site detection, we developed a point-of-care microfluidic channel-based device for direct measurement of fibrinogen concentration in whole blood. In our method, thrombin is dispersed on a reaction strip to initiate conversion of fibrinogen to fibrin. The permeability of the resulting blood clots depends on the fibrinogen level. A hydrophobic plastic protection flake between the reaction strip and a wicking strip is then removed to allow flow of unclotted blood. The rate of blood flow along the wicking strip was inversely related to the fibrinogen concentration. The whole process could be completed in as fast as 5 minutes for a whole blood sample size of 150 µL, and yielded accurate results ranging from 0 to 4 g L-1, which were unaffected by Ca2+, blood lipids, hematocrit, warfarin and tissue plasminogen activators (tPAs). Results using clinical whole blood samples were also highly consistent with those using an automatic coagulation analyzer, yielding a Pearson correlation coefficient of up to 0.919. This approach has potential for allowing rapid diagnosis of fibrinogen concentration in critically ill bleeding patients in different settings, thus helping to judge the suitability of fibrinogen replacement therapy (FRT) in cases of emergency bleeding and in patients at risk of thrombosis due to hyperfibrinogenemia.

Decreased synapse-associated proteins are associated with the onset of epileptic memory impairment in endothelial CDK5-deficient mice.

Accumulating evidence indicates that epilepsy has a higher risk of inducing memory impairment and dementia. However, the underlying onset mechanism remains unclear. Here, we found that mice with spontaneous epilepsy induced by endothelial CDK5 deficiency exhibited hippocampal-dependent memory impairment at 6 months of age, but not at 2 months of age. Moreover, the persistent epileptic seizures induce aberrant changes in phosphorylation of CaMKII protein in the hippocampus of spontaneous epileptic mice. Using genome-wide RNA sequencing and intergenic interaction analysis of STRING, we found that in addition to epilepsy-related genes, there are changes in synaptic organization pathway node genes, such as Bdnf and Grin1. The synapse-related proteins by Western blot analysis, such as NMDA receptors (NR1 and NR2B), PSD95, and the phosphorylation of synapsin1, are progressively decreased during epileptic seizures in Cdh5-CreERT2;CDK5f/f mice. Notably, we found that valproate (VPA) and phenytoin (PHT) augment mRNA expression and protein levels of synapse-related genes and ameliorate memory impairment in Cdh5-CreERT2;CDK5f/f mice. Our study elucidates a potential mechanism of memory deficits in epilepsy, and pharmacological reversal of synaptic pathology targeting might provide a new therapeutic intervention for epileptic memory deficits.

Optimization of Nanostructured Lipid Carriers of Fenofibrate Using a Box-Behnken Design for Oral Bioavailability Enhancement.

BACKGROUND: Fenofibrate (FNB) is a commonly used hypolipidemic agent. However, the oral bioavailability of FNB is limited by slow dissolution due to its low solubility. Thus, investigations on novel FNB formulations are necessary for their use. OBJECTIVE: The objective of this study is to enhance the oral bioavailability of FNB using optimized Nanostructured Lipid Carrier (NLC) formulations. METHODS: Hot homogenization followed by ultrasonication was used to prepare FNB-NLCs. These formulations were optimized using a Box-Behnken design, where the amount of FNB (X1), a ratio of solid lipid/liquid lipid (X2), and the percentage of emulsifier (X3) were set as independent variables, while the particle size (Y1), and Entrapment Efficiency (EE%) (Y2), were used as dependent factors. An in vitro dissolution test was then performed using a paddle method, while an in vivo pharmacokinetic study of FNB-NLC formulation was performed in rats. RESULTS: FNB-NLCs were successfully prepared and optimized using a Box-Behnken design. The particle size and EE% of the FNB-NLC had less than 5% difference from predicted values. The in vitro dissolution and oral bioavailability of the FNB-NLC were both higher than those of raw FNB. CONCLUSION: A Box-Behnken design was successfully applied to optimize FNB-NLC formulation for the enhancement of the dissolution and bioavailability of FNB, a poorly water-soluble drug.

Interannual variability of vegetation sensitivity to climate in China.

Many studies have assessed the relative sensitivity of ecosystems to climate change, and even optimized climate states from long-term averages to infer short-term changes, but how ecosystem sensitivity and its relationships with climate variability vary over time remains elusive. By combining the vegetation sensitivity index (VSI) and a 15 year moving window, we analyzed interannual variability in spatiotemporal patterns of vegetation sensitivity to short-term climate variability and its correlations with climatic factors in China over the past three decades (1982-2015). We demonstrated that vegetation sensitivity shows high spatial heterogeneity, and varies with vegetation type and climate region. Generally, vegetation in the southwest and mountainous regions was more sensitive, especially coniferous forests and isolated shrubland patches. Comparatively, vegetation in dry regions was less sensitive to climate variability than in wetter climates. Due to frequent climate variability in the early 1990s, a large increase in the VSI was detected in 1996. Significant increases in the interannual variability of vegetation sensitivity were observed in greater than 23.7% of vegetated areas and decreases in only 4.2%. Solar radiation was the dominant climate driver of vegetation sensitivity, followed by temperature and precipitation. However, climate controls are not invariable across a range of climatic conditions, such as precipitation exerted an increasing influence on changes of vegetation sensitivity. Quantitative analyses of ecosystem sensitivity to climate variability such as ours are vital to identify which regions and vegetation are most vulnerable to future climate variability.

Diverse response of vegetation growth to multi-time-scale drought under different soil textures in China's pastoral areas.

The pastoral areas of China are mainly located in ecologically fragile regions, where its ecosystems are highly sensitive to drought trends. Although numerous studies have been carried out on the response of vegetation to droughts, it is not entirely clear whether soil properties can influence this relationship. Using the Normalized Difference Vegetation Index (NDVI) and the Standardized Precipitation Evapotranspiration Index (SPEI), covering the period 1982 to 2015, we carefully analyzed drought impacts on vegetation in China's pastoral areas, to determine the effects of vegetation communities and soil types on vegetation response to multi-time-scale drought. Significantly positive correlations between NDVI and SPEI were observed in most regions, properly indicating that vegetation was largely influenced by drought, particularly the pastures in Inner Mongolia. Generally, forest was sensitive to longer time-scales of droughts, while grassland and cropland showed a close relationship with shorter or median drought time-scales. However, noticeable differences were found on the Tibetan Plateau, mainly because drought was not the main factor affecting vegetation growth in the region. The NDVI-SPEI correlations and the corresponding SPEI time-scales of each soil texture differed considerably, even in areas of the same land cover type, revealing that soil properties, here mainly refer to soil texture (classified by fractions of each separate soil, i.e., sand, silt, and clay), can assuredly affect the resistance and resilience of vegetation to drought stress. The underlying mechanism is the difference in particle size and permeability which can alter the storage and position of available soil water, thus affecting water absorption by the root system. Our results highlight the considerable importance of properly integrating edaphic factors when exploring the impact of likely climate change on ecosystems.

Cost-effectiveness analysis of cetuximab combined with chemotherapy as a first-line treatment for patients with RAS wild-type metastatic colorectal cancer based on the TAILOR trial.

OBJECTIVES: Cetuximab plus leucovorin, fluorouracil and oxaliplatin (FOLFOX-4) is superior to FOLFOX-4 alone as a first-line treatment for patients with metastatic colorectal cancer with RAS wild-type (RAS wt mCRC), with significantly improved survival benefit by TAILOR, an open-label, randomised, multicentre, phase III trial. Nevertheless, the cost-effectiveness of these two regimens remains uncertain. The following study aims to determine whether cetuximab combined with FOLFOX-4 is a cost-effective regimen for patients with specific RAS wt mCRC in China. DESIGN: A cost-effectiveness model combined decision tree and Markov model was built to simulate pateints with RAS wt mCRC based on health states of dead, progressive and stable. The health outcomes from the TAILOR trial and utilities from published data were used respectively. Costs were calculated with reference to the Chinese societal perspective. The robustness of the results was evaluated by univariate and probabilistic sensitivity analyses. PARTICIPANTS: The included patients were newly diagnosed Chinese patients with fully RAS wt mCRC. INTERVENTIONS: First-line treatment with either cetuximab plus FOLFOX-4 or FOLFOX-4. MAIN OUTCOME MEASURES: The primary outcomes are costs, quality-adjusted life-years (QALYs) and incremental cost-effectiveness ratios (ICERs). RESULTS: Baseline analysis disclosed that the QALYs was increased by 0.383 caused by additional cetuximab, while an increase of US$62 947 was observed in relation to FOLFOX-4 chemotherapy. The ICER was US$164 044 per QALY, which exceeded the willingness-to-pay threshold of US$28 106 per QALY. CONCLUSIONS: Despite the survival benefit, cetuximab combined with FOLFOX-4 is not a cost-effective treatment for the first-line regime of patients with RAS wt mCRC in China. TRIAL REGISTRATION NUMBER: TAILOR trial (NCT01228734); Post-results.

Emission reduction benefits and efficiency of e-waste recycling in China.

Recycling of e-waste is an effective means for e-waste management. It has made great contribution to improving environmental benefits. This paper evaluates the emission reduction benefits and efficiency of e-waste recycling in China, using the direction distance function of DEA. Calculations show that from 2013 to 2017, the total emission reduction benefits of 29 provinces in China e-waste was 6.34 billion yuan, with an average emission reduction efficiency of 0.88. The emission reduction benefits of CO2 was 390 million tons, and the average emission reduction efficiency was only 0.82. The wastewater emission reduction benefits was 570 million yuan, with an average efficiency of 0.9. The emission reduction benefits of solid waste and SO2 are 5.37 billion yuan and 400 million yuan respectively, with the same emission reduction efficiency of 0.89. E-waste recycling in China still has huge potential for emission reduction.

Ozone pollution in Chinese cities: Assessment of seasonal variation, health effects and economic burden.

The ground-level ozone (O3) concentration in the urban regions of China has become an increasingly noticeable environmental problem in recent years. Many epidemiological studies have reported the association between O3 pollution and mortality, only a few studies have focused on the O3-related mortality and corresponding economic effects at the Chinese city and province level. This study reports the seasonal variation of ground-level O3 in 338 cities of China during the year 2016 and evaluates its effect on premature mortality and economic loss. It further illustrates the differences in cause-specific mortality outcomes of the log-linear and linear model, two of the prominently used methods for estimating health effects. In 2016, the annual average daily maximum 8-h O3 concentration in China ranged between 74 and 201 µg/m3 (138 ±â€¯24.7 µg/m3). 30% of the total population was exposed to >160 µg/m3 O3 concentration (Chinese national ambient air quality standard) and about 67.2% urban population lived in exposure above the WHO recommended O3 concentrations (100 µg/m3). The estimated national O3-attributable mortality was 74.2 × 103 (95% CI: 16.7×103-127×103) in the log-linear model, whereas, the total O3-related mortality using the linear model was 69.6 × 103 (95% CI: 16.2 × 103-115 × 103). The exposure to O3 caused a nationwide economic loss of about 7.6 billion US$ (range: 1.7-12.9) in 2016. This study uniquely provides most comprehensive coverage of the Chinese cities for O3 associated mortality utilizing ground level measurement data for 2016 and presents a measurable assessment to the policymakers of China for streamlining their efforts on air quality improvement and O3 containment.

PM2.5-related health and economic loss assessment for 338 Chinese cities.

China is in a critical stage of ambient air quality management after global attention on pollution in its cities. Industrial development and urbanization have led to alarming levels of air pollution with serious health hazards in densely populated cities. The quantification of cause-specific PM2.5-related health impacts and corresponding economic loss estimation is crucial for control policies on ambient PM2.5 levels. Based on ground-level direct measurements of PM2.5 concentrations in 338 Chinese cities for the year 2016, this study estimates cause-specific mortality using integrated exposure-response (IER) model, non-linear power law (NLP) model and log-linear (LL) model followed by morbidity assessment using log-linear model. The willingness to pay (WTP) and cost of illness (COI) methods have been used for PM2.5-attributed economic loss assessment. In 2016 in China, the annual PM2.5 concentration ranged between 10 and 157 µg/m3 and 78.79% of the total population was exposed to >35 µg/m3 PM2.5 concentration. Subsequently, the national PM2.5-attributable mortality was 0.964 (95% CI: 0.447, 1.355) million (LL: 1.258 million and NPL: 0.770 million), about 9.98% of total reported deaths in China. Additionally, the total respiratory disease and cardiovascular disease-specific hospital admission morbidity were 0.605 million and 0.364 million. Estimated chronic bronchitis, asthma and emergency hospital admission morbidity were 0.986, 1.0 and 0.117 million respectively. Simultaneously, the PM2.5 exposure caused the economic loss of 101.39 billion US$, which is 0.91% of the national GDP in 2016. This study, for the first time, highlights the discrepancies associated with the three commonly used methodologies applied for cause-specific mortality assessment. Mortality and morbidity results of this study would provide a measurable assessment of 338 cities to the provincial and national policymakers of China for intensifying their efforts on air quality improvement.

Spatial-temporal patterns of PM2.5 concentrations for 338 Chinese cities.

Air pollution has become a major concern in cities worldwide. The present study explores the spatial-temporal patterns of PM2.5 (particles with an aerodynamic diameters ≤2.5µm) and the variation in the attainment rate (the number of cities attaining the national PM2.5 standard each day) at different time-scales based on PM2.5 concentrations. One-year of monitoring was conducted in 338 cities at or above the prefectural level in China. Spatial hot spots of PM2.5 were analyzed using exploratory spatial data analysis. Meteorological factors affecting PM2.5 distributions were analyzed. The results indicate the following: (1) Diurnal variations of PM2.5 exhibited a W-shaped trend, with the lowest value observed in the afternoon. The peak concentrations occurred after the ends of the morning and evening rush hours. (2) Out of 338 cities, 235 exceeded the national annual PM2.5 standards (≤35µg/m3), with slightly polluted (75-115µg/m3) cities occupying the greatest proportion. (3) The attainment rate showed an inverted U-shape, while there was a U-shaped pattern observed for daily and monthly mean PM2.5. (4) The spatial distribution of PM2.5 concentrations varied greatly, PM2.5 has significant spatial autocorrelation and clustering characteristics. Hot spots for pollution were mainly concentrated in the Beijing-Tianjin-Hebei area and neighboring regions, in part because of the large amount of smoke and dust emissions in this region. However, weather factors (temperature, humidity, and wind speed) also had an effect. In addition, southwest Xinjiang experienced heavy PM2.5 pollution that was mainly caused by the frequent occurrence of sandstorms, although no significant relationship was observed between PM2.5 and meteorological elements in this region.

Wogonin exacerbates the cytotoxic effect of oxaliplatin by inducing nitrosative stress and autophagy in human gastric cancer cells.

BACKGROUND: Gastric cancer remains one of the leading cause of death in the world. Drug combinations are potential approaches to provide more efficient treatments that minimize side effects. PURPOSE: We investigated the pharmacological effects of the combination of wogonin with oxaliplatin on gastric cancer cells in vitro and in vivo. METHODS AND RESULTS: In the present study, we found that wogonin enhanced the cytotoxicity of oxaliplatin; the drug combination resulted in strong synergistic inhibition of the cell viability in BGC-823 cells and in a zebrafish xenograft model. Interestingly, the combined treatment of wogonin and oxaliplatin modulated the expression of phospho-JNK (Thr183/Tyr185), phospho-ULK1 (Ser555) and the formation of LC3II. Confocal imaging data consistently showed that wogonin exacerbates the oxaliplatin-induced dissipation of the mitochondrial membrane potential (ΔΨm) and formation of peroxynitrite in BGC-823 cells. Moreover, wogonin allows a reduction in oxaliplatin dose when they are combined; therefore, it is a relevant strategy for reducing the side effects of oxaliplatin while achieving the same response. CONCLUSION: These results suggest that wogonin can be a potential therapeutic candidate for enhancing the efficacy of oxaliplatin in gastric cancer treatment.

Endothelial ErbB4 deficit induces alterations in exploratory behavior and brain energy metabolism in mice.

AIMS: The receptor tyrosine kinase ErbB4 is present throughout the primate brain and has a distinct functional profile. In this study, we investigate the potential role of endothelial ErbB4 receptor signaling in the brain. RESULTS: Here, we show that the endothelial cell-specific deletion of ErbB4 induces decreased exploratory behavior in adult mice. However, the water maze task for spatial memory and the memory reconsolidation test reveal no changes; additionally, we observe no impairment in CaMKII phosphorylation in Cdh5Cre;ErbB4f/f mice, which indicates that the endothelial ErbB4 deficit leads to decreased exploratory activity rather than direct memory deficits. Furthermore, decreased brain metabolism, which was measured using micro-positron emission tomography, is observed in the Cdh5Cre;ErbB4f/f mice. Consistently, the immunoblot data demonstrate the downregulation of brain Glut1, phospho-ULK1 (Ser555), and TIGAR in the endothelial ErbB4 conditional knockout mice. Collectively, our findings suggest that endothelial ErbB4 plays a critical role in regulating brain function, at least in part, through maintaining normal brain energy homeostasis. CONCLUSIONS: Targeting ErbB4 or the modulation of endothelial ErbB4 signaling may represent a rational pharmacological approach to treat neurological disorders.

Retrospective analysis of tigecycline shows that it may be an option for children with severe infections.

AIM: This study assessed the efficacy and safety of tigecycline in children with life-threatening infections. METHODS: We retrospectively reviewed the clinical records of patients treated with tigecycline from June 2012 to May 2014 in a Chinese tertiary centre. RESULTS: The study comprised 24 patients (14 male) with a median age of four years (range, 50 days-12 years). The most frequently isolated microorganism, most common isolation site and type of infection were Acinetobacter baumannii, tracheal aspirate fluid and ventilator-associated pneumonia, respectively. Tigecycline was administered at a loading dose of 1.5 or 2.0 mg/kg and 1.0 mg/kg every 12 hours after that. The average duration of treatment was 11.6 ± 5.8 days. The clinical response and microbiological eradication rate were 37.5% and 29.2%, respectively. Six of the patients we studied (25.0%) died, and three of these deaths were considered to be infection related. Adverse drug reactions were identified in four patients (16.7%) during the treatment, including abnormal liver function, prolonged prothrombin time and diarrhoea. CONCLUSION: Our findings suggest that tigecycline may be an option for children with severe infections. However, more prospective, controlled trials are required to objectively evaluate the efficacy and safety of tigecycline in children.

Visualizing peroxynitrite fluxes in endothelial cells reveals the dynamic progression of brain vascular injury.

Accumulating evidence suggests that formation of peroxynitrite (ONOO(-)) in the cerebral vasculature contributes to the progression of ischemic damage, while the underlying molecular mechanisms remain elusive. To fully understand ONOO(-) biology, efficient tools that can realize the real-time tracing of endogenous ONOO(-) fluxes are indispensable. While a few ONOO(-) fluorescent probes have been reported, direct visualization of ONOO(-) fluxes in the cerebral vasculature of live mice remains a challenge. Herein, we present a fluorescent switch-on probe (NP3) for ONOO(-) imaging. NP3 exhibits good specificity, fast response, and high sensitivity toward ONOO(-) both in vitro and in vivo. Moreover, NP3 is two-photon excitable and readily blood-brain barrier penetrable. These desired photophysical and pharmacokinetic properties endow NP3 with the capability to monitor brain vascular ONOO(-) generation after injury with excellent temporal and spatial resolution. As a proof of concept, NP3 has enabled the direct visualization of neurovascular ONOO(-) formation in ischemia progression in live mouse brain by use of two-photon laser scanning microscopy. Due to these favorable properties, NP3 holds great promise for visualizing endogenous peroxynitrite fluxes in a variety of pathophysiological progressions in vitro and in vivo.

Nitrosative stress induces peroxiredoxin 1 ubiquitination during ischemic insult via E6AP activation in endothelial cells both in vitro and in vivo.

AIMS: Although there is accumulating evidence that increased formation of reactive nitrogen species in cerebral vasculature contributes to the progression of ischemic damage, but the underlying molecular mechanisms remain elusive. Peroxiredoxin 1 (Prx1) can initiate the antioxidant response by scavenging free radicals. Therefore, we tested the hypothesis that Prx1 regulates the susceptibility to nitrosative stress damage during cerebral ischemia in vitro and in vivo. RESULTS: Proteomic analysis in endothelial cells revealed that Prx1 was upregulated after stress-related oxygen-glucose deprivation (OGD). Although peroxynitrite upregulated Prx1 rapidly, this was followed by its polyubiquitination within 6 h after OGD mediated by the E3 ubiquitin ligase E6-associated protein (E6AP). OGD colocalized E6AP with nitrotyrosine in endothelial cells. To assess translational relevance in vivo, mice were studied after middle cerebral artery occlusion (MCAO). This was accompanied by Prx1 ubiquitination and degradation by the activation of E6AP. Furthermore, brain delivery of a lentiviral vector encoding Prx1 in mice inhibited blood-brain barrier leakage and neuronal damage significantly following MCAO. INNOVATION AND CONCLUSIONS: Nitrosative stress during ischemic insult activates E6AP E3 ubiquitin ligase that ubiquitinates Prx1 and subsequently worsens cerebral damage. Thus, targeting the Prx1 antioxidant defense pathway may represent a novel treatment strategy for neurovascular protection in stroke.

The disturbance of hippocampal CaMKII/PKA/PKC phosphorylation in early experimental diabetes mellitus.

BACKGROUND: Defining the impact of diabetes and related risk factors on brain cognitive function is critically important for patients with diabetes. AIMS: To investigate the alterations in hippocampal serine/threonine kinases signaling in the early phase of type 1 and type 2 diabetic rats. METHODS: Early experimental diabetes mellitus was induced in rats with streptozotocin or streptozotocin/high fat. Changes in the phosphorylation of proteins were determined by immunoblotting and immunohistochemistry. RESULTS: Our data showed a pronounced decrease in the phosphorylation of Ca(2+) /calmodulin-dependent protein kinase II (CaMKII) in the hippocampi of both type 1 and type 2 diabetic rats compared with age-matched control rats. Unexpectedly, we found a significant increase in the phosphorylation of synapsin I (Ser 603) and GluR1 (Ser 831) in the same experiment. In addition, aberrant changes in hippocampal protein kinase C (PKC) and protein kinase A (PKA) signaling in type 1 and type 2 diabetic rats were also found. Moreover, PP1α and PP2A protein levels were decreased in the hippocampus of type 1 diabetic rats, but significantly up-regulated in type 2 diabetic rats. CONCLUSIONS: The disturbance of CaMKII/PKA/PKC phosphorylation in the hippocampus is an early change that may be associated with the development and progression of diabetes-related cognitive dysfunction.