Increasing evidence suggests that long noncoding RNAs (lncRNAs) play crucial roles in various biological processes. However, little is known about the effects of lncRNAs on autophagy. Here we report ...that a lncRNA, termed cardiac autophagy inhibitory factor (CAIF), suppresses cardiac autophagy and attenuates myocardial infarction by targeting p53-mediated myocardin transcription. Myocardin expression is upregulated upon H
O
and ischemia/reperfusion, and knockdown of myocardin inhibits autophagy and attenuates myocardial infarction. p53 regulates cardiomyocytes autophagy and myocardial ischemia/reperfusion injury by regulating myocardin expression. CAIF directly binds to p53 protein and blocks p53-mediated myocardin transcription, which results in the decrease of myocardin expression. Collectively, our data reveal a novel CAIF-p53-myocardin axis as a critical regulator in cardiomyocyte autophagy, which will be potential therapeutic targets in treatment of defective autophagy-associated cardiovascular diseases.
The unprecedented early spring frost that appears as a cold stress adversely affects growth and productivity in tea (
L.); therefore, it is indispensable to develop approaches to improve the cold ...tolerance of tea. Here, we investigated the effect of pretreatment with exogenous melatonin on the net photosynthetic rate, the maximum photochemical efficiency of PSII, chlorophyll content, lipid peroxidation, reactive oxygen species (ROS) accumulation, antioxidant potential, and redox homeostasis in leaves of tea plants following cold stress. Our results revealed that cold treatment induced oxidative stress by increasing ROS accumulation, which in turn affected the photosynthetic process in tea leaves. However, treatment with melatonin mitigated cold-induced reductions in photosynthetic capacity by reducing oxidative stress through enhanced antioxidant potential and redox homeostasis. This study provides strong evidence that melatonin could alleviate cold-induced adverse effects in tea plants.
The phytohormone salicylic acid (SA) is a secondary metabolite that regulates plant growth, development and responses to stress. However, the role of SA in the biosynthesis of flavonoids (a large ...class of secondary metabolites) in tea (
L.) remains largely unknown. Here, we show that exogenous methyl salicylate (MeSA, the methyl ester of SA) increased flavonoid concentration in tea leaves in a dose-dependent manner. While a moderate concentration of MeSA (1 mM) resulted in the highest increase in flavonoid concentration, a high concentration of MeSA (5 mM) decreased flavonoid concentration in tea leaves. A time-course of flavonoid concentration following 1 mM MeSA application showed that flavonoid concentration peaked at 2 days after treatment and then gradually declined, reaching a concentration lower than that of control after 6 days. Consistent with the time course of flavonoid concentration, MeSA enhanced the activity of phenylalanine ammonia-lyase (PAL, a key enzyme for the biosynthesis of flavonoids) as early as 12 h after the treatment, which peaked after 1 day and then gradually declined upto 6 days. qRT-PCR analysis of the genes involved in flavonoid biosynthesis revealed that exogenous MeSA upregulated the expression of genes such as
,
,
,
,
,
,
,
and
in tea leaves. These results suggest a role for MeSA in modulating the flavonoid biosynthesis in green tea leaves, which might have potential implications in manipulating the tea quality and stress tolerance in tea plants.
Rising CO
concentration, a driving force of climate change, is impacting global food security by affecting plant physiology. Nevertheless, the effects of elevated CO
on primary and secondary ...metabolism in tea plants (Camellia sinensis L.) still remain largely unknown. Here we showed that exposure of tea plants to elevated CO
(800 µmol mol
for 24 d) remarkably improved both photosynthesis and respiration in tea leaves. Furthermore, elevated CO
increased the concentrations of soluble sugar, starch and total carbon, but decreased the total nitrogen concentration, resulting in an increased carbon to nitrogen ratio in tea leaves. Among the tea quality parameters, tea polyphenol, free amino acid and theanine concentrations increased, while the caffeine concentration decreased after CO
enrichment. The concentrations of individual catechins were altered differentially resulting in an increased total catechins concentration under elevated CO
condition. Real-time qPCR analysis revealed that the expression levels of catechins and theanine biosynthetic genes were up-regulated, while that of caffeine synthetic genes were down-regulated in tea leaves when grown under elevated CO
condition. These results unveiled profound effects of CO
enrichment on photosynthesis and respiration in tea plants, which eventually modulated the biosynthesis of key secondary metabolites towards production of a quality green tea.
Cordycepin, an adenosine analog, has been reported to improve cognitive function, but which seems to be inconsistent with the reports showing that cordycepin inhibited long‐term potentiation (LTP). ...Behavioral‐LTP is usually used to study long‐term synaptic plasticity induced by learning tasks in freely moving animals. In order to investigate simultaneously the effects of cordycepin on LTP and behavior in rats, we applied the model of behavioral‐LTP induced by Y‐maze learning task through recording population spikes in hippocampal CA1 region. Golgi staining and Sholl analysis were employed to assess the morphological structure of dendrites in pyramidal cells of hippocampal CA1 area, and western blotting was used to examine the level of adenosine A1 receptors and A2A receptors (A2AR). We found that cordycepin significantly improved behavioral‐LTP magnitude, accompanied by increases in the total length of dendrites, the number of intersections and spine density but did not affect Y‐maze learning task. Furthermore, cordycepin obviously reduced A2AR level without altering adenosine A1 receptors level; and the agonist of A2AR (CGS 21680) rather than antagonist (SCH 58261) could reverse the potentiation of behavioral‐LTP induced by cordycepin. These results suggested that cordycepin improved behavioral‐LTP and morphological structure of dendrite in hippocampal CA1 but did not contribute to the improvement of learning and memory. And cordycepin improved behavioral‐LTP may be through reducing the level of A2AR in hippocampus. Collectively, the effects of cordycepin on cognitive function and LTP were complex and involved multiple mechanisms.
Cordycepin has been shown to improve cognitive function and inhibit long‐term potentiation (LTP). Behavioral‐LTP is usually used to study long‐term synaptic plasticity induced by behavioral trainings in freely moving animals. We found that cordycepin improved behavioral‐LTP magnitude, accompanied by increases in the total length of dendrites, the number of intersections and spine density. Furthermore, cordycepin reduced adenosine A2A receptors (A2AR) level and the agonist of A2AR could reverse the potentiation of behavioral‐LTP induced by cordycepin. These results suggested that A2AR maybe involve in the neuroprotective effect of cordycepin.
Salinity is a global environmental problem, restricting crop production in a vast area of agricultural land. Although epigallocatechin-3-gallate (EGCG), the most abundant polyphenol in tea plants, ...has a strong antioxidative action in vitro, the role of EGCG in the plant response to salt stress remains unknown. In the present study, using a series of EGCG concentrations (10, 100, and 1000 µM), we showed that EGCG could alleviate salt stress-induced inhibition in seed germination and root growth in tomato. Exogenous EGCG increased not only the seed germination rate, but also the germination energy and germination index under salt stress. The 150 mM NaCl treatment significantly increased lipid peroxidation in roots by excessive accumulation of reactive oxygen species (ROS). In contrast, EGCG treatment, particularly at 100 µM concentration, mitigated NaCl-induced oxidative stress as evidenced by the decreased H
2
O
2
and malondialdehyde content in roots. Analysis of the antioxidant enzyme system reveals that EGCG increased the activity of superoxide dismutase, peroxidase, ascorbate peroxidase, and catalase under salt stress. Considering the beneficial effect of EGCG on seed germination, root growth, ROS scavenging, and antioxidant enzyme activity, the 100 µM EGCG treatment appears to be the most effective concentration of those tested under salt stress in tomato. Our results suggest that the EGCG-promoted tomato tolerance to salt stress is associated with the mitigation of oxidative stress through an efficient ROS scavenging mechanism by the action of enhanced antioxidant enzyme activity. Thus, the enhancement of plant tolerance by exogenous EGCG can potentially expand crop cultivation in saline soils.
RATIONALE:Uncontrolled growth of abdominal aortic aneurysms (AAAs) is a life-threatening vascular disease without an effective pharmaceutical treatment. AAA incidence dramatically increases with ...advancing age in men. However, the molecular mechanisms by which aging predisposes individuals to AAAs remain unknown.
OBJECTIVE:In this study, we investigated the role of Sirtuin 1 (SIRT1), a class III histone deacetylase, in AAA formation and the underlying mechanisms linking vascular senescence and inflammation.
METHODS AND RESULTS:The expression and activity of SIRT1 were significantly decreased in human AAA samples. SIRT1 in vascular smooth muscle cells (VSMCs) was remarkably downregulated in the suprarenal aortas of aged mice, in which AAAs induced by Ang II infusion were significantly elevated. Moreover, VSMC-specific knockout of SIRT1 accelerated Ang II-induced formation and rupture of AAAs and AAA-related pathological changes, whereas VSMC-specific overexpression of SIRT1 suppressed Ang II-induced AAA formation and progression in Apoe mice. Furthermore, the inhibitory effect of SIRT1 on AAA formation was also proved in a calcium chloride (CaCl2)–induced AAA model. Mechanistically, the reduction of SIRT1 was shown to increase vascular cell senescence and upregulate p21 expression as well as enhance vascular inflammation. Notably, inhibition of p21-dependent vascular cell senescence by SIRT1 blocked Ang II-induced NF-κB binding on the promoter of monocyte chemoattractant protein-1 (MCP-1/CCL2) and inhibited its expression.
CONCLUSION:These findings provide evidence that SIRT1 reduction links vascular senescence and inflammation to AAAs, and that SIRT1 in VSMCs provides a therapeutic target for the prevention of AAA formation.
BACKGROUND:The adult mammalian cardiomyocytes lose their proliferative capacity, which is responsible for cardiac dysfunction and heart failure following injury. The molecular mechanisms underlying ...the attenuation of adult cardiomyocyte proliferation remain largely unknown. Because long noncoding RNAs (lncRNAs) have a critical role in the development of cardiovascular problems, we investigated whether lncRNAs have any role in the regulation of cardiomyocyte proliferation and cardiac repair.
METHODS:Using bioinformatics and initial analysis, we identified an lncRNA, named CPR (cardiomyocyte proliferation regulator), that has a potential regulatory role in cardiomyocyte proliferation. For in vivo experiments, we generated CPR knockout and cardiac-specific CPR-overexpressing mice. In isolated cardiomyocytes, we used adenovirus for silencing (CPR–small interfering RNA) or overexpressing CPR. To investigate the mechanisms of CPR function in cardiomyocyte proliferation, we performed various analyses including quantitative reverse transcription–polymerase chain reaction, Western blot, histology, cardiac function (by echocardiography), transcriptome analyses (microarray assay), RNA pull-down assay, and chromatin immunoprecipitation assay.
RESULTS:CPR level is comparatively higher in the adult heart than in the fetal stage. The silencing of CPR significantly increased cardiomyocyte proliferation in postnatal and adult hearts. Moreover, CPR deletion restored the heart function after myocardial injury, which was evident from increased cardiomyocyte proliferation, improvement of myocardial function, and reduced scar formation. In contrast, the neonatal cardiomyocyte proliferation and cardiac regeneration were remarkably suppressed in CPR-overexpressing mice or adeno-associated virus serotype 9–CPR—overexpressing heart. These results indicate that CPR acts as a negative regulator of cardiomyocyte proliferation and regeneration. Next, we found that CPR targets minichromosome maintenance 3, an initiator of DNA replication and cell cycle progression, to suppress cardiomyocyte proliferation. CPR silenced minichromosome maintenance 3 expression through directly interacting and recruiting DNMT3A to its promoter cysteine-phosphate-guanine sites, as evident from decreased minichromosome maintenance 3 promoter methylation and increased minichromosome maintenance 3 expression in CPR knocked-down cardiomyocytes and CPR knockout mouse heart. These results were confirmed in CPR-overexpressing cardiomyocytes and CPR-overexpressing mouse heart.
CONCLUSIONS:Together, our findings identified that CPR is a suppressor of cardiomyocyte proliferation and indicated that lncRNAs take part in the regulation of cardiomyocyte proliferation and cardiac repair. Our study provides an lncRNA-based therapeutic strategy for effective cardiac repair and regeneration.
This work mainly focuses to review the recent progress of MOFs in different sorption and separation, and highlight the control approaches of the pore properties of MOFs on the capture and separation ...of the tailored guest molecules by various supramolecular interactions for the first time.
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•This review introduced the inherent pore properties of MOFs.•Some specific strategies are presented to improve the capture/separation of MOFs.•The supramolecular interactions are discussed between adsorbates and adsorbents.•The review prospected the sorption/separation applications of porous MOF materials.
Because the adsorption/separation process plays a great role in chemical, petrochemical, pharmaceutical, environmental protection and many other fields, it has received extensive concern in both scientific research and practical applications. However, due to the new requirements and specific applications, it is a great necessity and urgency to explore new-type porous materials or maximize the adsorption capacity and improve the separation efficiency through endowing the adsorbent functionality to enable its special interactions with the adsorbates. The crystalline metal–organic framework (MOF) materials have shown great potentials in gas/liquid phase capture and separation due to their enormous porosities, tunable void properties, and easier modification, etc. Although there are lots of excellent reviews about functional MOFs in different fields, this review introduces the influence of MOF pore properties on the capture and separation of tailored guest molecules from the control of the supramolecular interactions for the first time. Some specific strategies are thus presented to enhance the adsorption/separation performance, and the relationships of the supramolecular interactions are well discussed between the adsorbates and adsorbents. Finally, the applications of porous MOF materials in adsorption/separation are further prospected and provided by the recent relevant studies.
► FTIR and 3D-EEM are used to analyse the main components of EPS in aerobic granule. ► Results indicate the importance of aromatic protein-like substances in the stable granular sludge. ► The isomers ...of carbohydrates (1110–1047cm−1) can be attributed to the aerobic sludge granulation.
In recent years, lots of the extracellular polymeric substances (EPS) related researches have focused on its role in the granulation and structural stability of aerobic sludge. Three-dimensional fluorescence spectrum (3D-EEM) and fourier transform infrared spectroscopy (FTIR) technologies were used to analyse the main components of sludge EPS during aerobic sludge granulation in this study. Results showed that the components of sludge EPS tended to be stable during aerobic sludge granulation. The peak F (Ex/Em=230/308.5) from 3D-EEM and the predominant spectral band at approximately 1517cm−1 from the FTIR spectra of the matured granular sludge indicated the importance of aromatic protein-like substances together, especially tyrosine in maintaining the stable structure of the granular sludge. Furthermore, the differences in the occurrence position and frequency of C–O bonds (1110–1047cm−1) observed during aerobic sludge granulation showed that the transformations between the isomers and other forms of carbohydrates may be attributed to the formation of aerobic granule.
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