Cisplatin-resistance induces lung squamous carcinoma cell growth by nicotine-mediated α7nAchR/HDAC1/Cyclin D1/pRb cell cycle activation.

The majority of adenocarcinoma lung cancer is found in nonsmokers. A history of tobacco use is more common in squamous cell carcinoma of the lung. The aim of this study is to identify the cisplatin (CDDP)-resistance that promotes lung squamous carcinoma cell growth through nicotine-mediated HDAC1/7nAchR/E2F/pRb cell cycle activation. Squamous cell carcinoma (NCI-H520 and NCI-H157) cells were examined after cisplatin and nicotine treatment by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide assay, cell migration assay, immunofluorescence staining, western blot analysis, and immunoprecipitation analysis. Consequently, CDDP is released from DNA and Rb phosphorylated pRb as a result of nicotine-induced cancer cell proliferation through 7nAchR, which then triggers the opening of the HDAC1 cell cycle. The cell cycle is stopped when CDDP adducts are present. Nicotine exerts cancer cytoprotective effects by allowing HDAC1 repair mechanisms to re-establish E2F promoting DNA stimulation cell cycle integrity in the cytosol and preventing potential CDDP and HDAC1 suppressed in the nuclear. Concentration expression of nicotine causes squamous carcinoma cell carcinogens to emerge from inflammation. COX2, NF-KB, and NOS2 increase as a result of nicotine-induced squamous carcinoma cell inflammation. Nicotine enhanced the cell growth-related proteins such as α7nAchR, EGFR, HDAC1, Cyclin D, Cyclin E, E2F, Rb, and pRb by western blot analysis. It also induced cancer cell inflammation and growth. As a result, we suggest that nicotine will increase the therapeutic resistance effects of CDDP. This has the potential to interact with nicotine through α7nAchR receptors and HDAC1/Cyclin D/E2F/pRb potentially resulting in CDDP therapy resistance, as well as cell cycle-induced cancer cell growth.

Accurate carbon storage estimation for the salt marsh ecosystem based on Bayesian maximum entropy approach - A case study for the Spartina alterniflora ecosystem.

The blue carbon ecosystem, including the salt marsh ecosystem, possesses a significant carbon sequestration potential. Therefore, accurately quantifying the carbon storage within such ecosystems is crucial for the adequate accounting of carbon sequestration. The present work chose a Spartina alterniflora ecosystem in the Xiaogan Island (China) as the study area (approximately 11 ha), and employed the Bayesian maximum entropy (BME) approach to assimilate both hard organic carbon (OC) data and soft OC data measured from 2 cm and 10 cm stratified samples. A 3-dimensional model was developed for space-time OC estimation purposes based on the sediment chronology results. The 10-fold BME cross validation results demonstrated a high estimation accuracy, with the R2, RMSE and MAE values equal to 0.8564, 0.1026 % and 0.0748 %, respectively. A noteworthy outcome was the BME-generated carbon storage density maps with 1 m spatial resolution. These maps revealed that the carbon storage density at the top 30 cm sediment depth in the stable zone (with elder stand age of S. alterniflora) was higher than that in the rapid expansion zone, i.e., 71.79 t/ha vs. 69.82 t/ha, respectively. Additionally, the study found that the averaged carbon burial rate and the total carbon storage at the top 30 cm sediment depth across the study area were 266 g C/m2/yr and 781.50 t, respectively. Lastly, the proposed BME-based framework of carbon storage estimation was found to be versatile and applicable to other blue carbon ecosystems. This approach can foster the development of a standardized carbon sink metrological methodology for diverse blue carbon ecosystems.

The emerging roles of MAPK-AMPK in ferroptosis regulatory network.

Ferroptosis, a newform of programmed cell death, driven by peroxidative damages of polyunsaturated-fatty-acid-containing phospholipids in cellular membranes and is extremely dependent on iron ions, which is differs characteristics from traditional cell death has attracted greater attention. Based on the curiosity of this new form of regulated cell death, there has a tremendous progress in the field of mechanistic understanding of ferroptosis recent years. Ferroptosis is closely associated with the development of many diseases and involved in many diseases related signaling pathways. Not only a variety of oncoproteins and tumor suppressors can regulate ferroptosis, but multiple oncogenic signaling pathways can also have a regulatory effect on ferroptosis. Ferroptosis results in the accumulation of large amounts of lipid peroxides thus involving the onset of oxidative stress and energy stress responses. The MAPK pathway plays a critical role in oxidative stress and AMPK acts as a sensor of cellular energy and is involved in the regulation of the energy stress response. Moreover, activation of AMPK can induce the occurrence of autophagy-dependent ferroptosis and p53-activated ferroptosis. In recent years, there have been new advances in the study of molecular mechanisms related to the regulation of ferroptosis by both pathways. In this review, we will summarize the molecular mechanisms by which the MAPK-AMPK signaling pathway regulates ferroptosis. Meanwhile, we sorted out the mysterious relationship between MAPK and AMPK, described the crosstalk among ferroptosis and MAPK-AMPK signaling pathways, and summarized the relevant ferroptosis inducers targeting this regulatory network. This will provide a new field for future research on ferroptosis mechanisms and provide a new vision for cancer treatment strategies. Video Abstract.

Impact of bentonite on greenhouse gas emissions during pig manure composting and its subsequent application.

Additives were widely investigated to retain the nutrients and mitigate the greenhouse gas emissions (GHGs) during manure composting. However, the sustained effects of additives on the GHGs emissions following incorporation of composts to soil were scarcely explored. This study evaluated the effects of bentonite added at the beginning of pig manure composting on the GHGs emissions during two successive processes, i.e., composting and soil incubation amended with composting products. Addition of bentonite did not hinder the composting process and alter the total CO2 emission. On the other hand, reduction by about 17% and 29% for CH4 and N2O emission, respectively, was achieved in the presence of bentonite during composting. Incorporation of the final composting products to soil enhanced significantly the soil C and N of various forms, and gas emissions of CO2 and N2O. However, no significant differences were observed between bentonite-manure co-compost and manure-only compost application except for the N2O emission. Compared to the manure-only compost, compost amended with bentonite reduced N2O loss by around 6.8%, but not statistically significant. This study confirmed that addition of bentonite at the composting stage can mitigate the GHGs emission considering both composting and compost application stages, with all reductions occurring at the composting stage.

Periodicity and global order parameter of hexagonally packed cylinders in a periodic box.

In all molecular simulations of periodic ordered morphologies (such as those formed by block copolymers), the periodic boundary conditions (PBCs) of the simulation box usually do not match the bulk periodicity L0 of the morphology, thus changing the structure and even the stability of the morphologies obtained in the simulations. To address this problem for hexagonally packed cylinders, we first proposed a general method of calculating the periodicity of such cylinders in a cuboid simulation box with the PBCs applied in all directions, which further allows one to enumerate all possible orientations and periodicities of such cylinders within an estimated range that can fit into a cuboid box of given lengths. We then showed how to choose the lengths of a cuboid box such that regular-hexagonally packed (RHP) cylinders with given intercylinder distance and orientation can fit into the box. Next, taking as an example the dissipative particle dynamics (DPD) simulations of a cylinder-forming diblock copolymer melt, we showed that L0 of RHP cylinders oriented along the body diagonal of a cubic box is found when all the off-diagonal elements of the pressure tensor vanish. Finally, based on our general method of calculating the periodicity of hexagonally packed cylinders, we designed a global order parameter for such cylinders, which takes into account their ordering only for the orientations that can fit into the simulation box. Using again the DPD simulations, we showed that our global order parameter can be used to quantify the formation of hexagonally packed cylinders in each collected configuration and to monitor their orientation (thus periodicity) during the simulation run.

Stocks and losses of soil organic carbon from Chinese vegetated coastal habitats.

Global vegetated coastal habitats (VCHs) represent a large sink for organic carbon (OC) stored within their soils. The regional patterns and causes of spatial variation, however, remain uncertain. The sparsity and regional bias of studies on soil OC stocks from Chinese VCHs have limited the reliable estimation of their capacity as regional and global OC sinks. Here, we use field and published data from 262 sampled soil cores and 181 surface soils to report estimates of soil OC stocks, burial rates and losses of VCHs in China. We find that Chinese mangrove, salt marsh and seagrass habitats have relatively low OC stocks, storing 6.3 ± 0.6, 7.5 ± 0.6, and 1.6 ± 0.6 Tg C (±95% confidence interval) in the top meter of the soil profile with burial rates of 44 ± 17, 159 ± 57, and 6 ± 45 Gg C/year, respectively. The variability in the soil OC stocks is linked to biogeographic factors but is mostly impacted by sedimentary processes and anthropic activities. All habitats have experienced significant losses, resulting in estimated emissions of 94.2-395.4 Tg CO2 e (carbon dioxide equivalent) over the past 70 years. Reversing this trend through conservation and restoration measures has, therefore, great potential in contributing to the mitigation of climate change while providing additional benefits. This assessment, on a national scale from highly sedimentary environments under intensive anthropogenic pressures, provides important insights into blue carbon sink mechanism and sequestration capacities, thus contributing to the synchronous progression of global blue carbon management.

Phase behavior of ABC cyclic terpolymer melts: a simulation study.

The phase behavior of ABC cyclic terpolymer melts is investigated using a simulated annealing technique. A ternary phase diagram is constructed by tuning the volume fractions of the three blocks (fA, fB, and fC) in the case of symmetric interactions. 11 phases are predicted, including lamellae with spheres at the interfaces, lamellae with spheres inside a domain, lamellae with spheres inside domains, cylinders in perforated lamellae, [6.6.6] tiling patterns, lamella + cylinder, hierarchical double-gyroid, columnar piled disk, patched spheres, cylinders with spheres at the interfaces and double gyroid with spheres at the interfaces. In these structures, the end segments of the three blocks tend to distribute uniformly on the A/B, B/C, or A/C interfaces, which may result in superior mechanical properties of the structures in cyclic terpolymer systems than those of the same structures formed in star or linear terpolymer systems. The physical reason for the similarities and differences between the phases formed in ABC cyclic and star terpolymer systems is investigated. Our simulation results are compared with related experimental observations and theoretical calculations.

Lattice self-consistent field calculations of confined symmetric block copolymers of various chain architectures.

The effects of chain architecture and confinement on the structure and orientation of lamellae formed by incompressible and symmetric AB-type block copolymer melts confined between two parallel and identical surfaces are investigated using self-consistent field calculations on a simple cubic lattice. Five systems of various chain architectures (linear, ring, and star) and lengths are studied, with their bulk lamellar period L0 chosen such that they have comparable L0/Rg, where Rg denotes the ideal-chain radius of gyration. For thin films of thickness D = L0 confined between two neutral surfaces, we define the rescaled volume fraction profiles of A, B, chain end, and joint segments in the parallel and perpendicular lamellae such that these profiles can be directly compared among the five systems to quantitatively reveal the interplay between the chain-end enrichment near confining surfaces and the surface-induced A-B compatibilization, and how such interplay is affected by the chain architectures (for example, the chain-crowding effects in the star block copolymers). The effects of D and surface preference for one of the blocks are also investigated.

Combination of exercise training and resveratrol attenuates obese sarcopenia in skeletal muscle atrophy.

Obese sarcopenia is a progressive loss of skeletal muscle mass and strength with increases in adipocytes. The aim of this study was to investigate the effects of combination of exercise training and resveratrol on the pathological pathway from obesity to sarcopenia, and potential therapy for skeletal muscle declines in physical function. Two animal models were experimented: (1) C57BL/6J male mice were fed either a high-fat diet (HFD) for 8 weeks to induce obesity and resveratrol (low-, middle-, and high-dose) for 4 weeks. (2) senescence-accelerated mouse prone 8 (SAMP8) mice with sarcopenia were used. Skeletal muscle function of SAMP8 mice expressed an age-associated decline. In SAMP8 mice, resveratrol (150 mg/Kg BW, daily) was administered by oral gavage two times a week for 1 month of the experimental period. Exercise training based on adaptations in the muscle is training twice a week for 4 weeks. SAMP8 mouse skeletal muscle in each group was analyzed by H and E staining, transferase dUTP nick end labeling, and Western blot analysis. Mitochondrial function expression, apoptosis and relative hypertrophy signaling in HFD-induced obesity mice and SAMP8 mice were determined by Western blot analysis. Results of the present study indicate that effect of resveratrol on skeletal muscles of HFD-induced obesity mice is linked to an increase in Bcl-2 and phosphatidylinositol 3 kinase/AKT expressions. On the other hand, resveratrol, and its combination with exercise training, attenuate the aging-related mitochondrial dysfunction involving Bad, caspase 3, and interleukin-6 expressions in SAMP8 mice. Combination of exercise training and resveratrol induced hypertrophy in skeletal muscles of sarcopenia SAMP8 mice. Therefore, we suggest combination of exercise training and resveratrol as a therapeutic potential in obese sarcopenia.

Controllable construction of isoquinolinedione and isocoumarin scaffolds via RhIII-catalyzed C-H annulation of N-tosylbenzamides with diazo compounds.

A highly efficient protocol for the synthesis of isoquinolinediones by RhIII-catalyzed C-H activation/annulation/decarboxylation of N-tosylbenzamides with diazo compounds is reported. The switchable synthesis of isocoumarins was also achieved successfully via C-H activation/annulation with slight modification of the reaction conditions. Importantly, the synthetic utility of this new reaction was further demonstrated in an atom-economical and operationally convenient total synthesis of a TDP2 inhibitor derivative from commercially available starting materials.

Warming Amplifies the Frequency of Harmful Algal Blooms with Eutrophication in Chinese Coastal Waters.

Widespread coastal eutrophication is known to increase the prevalence of harmful algal blooms (HABs). Increased HABs have also been linked to climate change, with ocean warming predicted to lead to increased prevalence and earlier timing of HABs. Testing the predictions of warming to HABs is difficult due to the lack of long-term observations across spatial scales. Here, we use a 45 year (1970-2015) record of the occurrence and duration of HABs along Chinese coast to show that the HAB frequency has increased at a rate of 40 ± 4% decade-1, with earlier timing by 5.50 ± 1.78 days decade-1. The increasing frequency of blooms varied with latitude and is significantly correlated with warming at an average rate of 0.17 ± 0.03 °C decade-1, with the positive relationship being strongest in more eutrophic provinces. HAB frequency increased with elevated dissolved inorganic nutrient concentration, but this increase was amplified further with warming. Warming and eutrophication showed additive roles in triggering HABs. Swift action to mitigate eutrophication is essential to avoid a sharp increase in the HABs in coastal waters with further warming.

Association of Kidney Function Tests with a Cardio-Ankle Vascular Index in Community-Dwelling Individuals with a Normal or Mildly Decreased Estimated Glomerular Filtration Rate.

Background and objectives: Chronic kidney disease (CKD) is an independent risk factor for cardiovascular disease (CVD). Previous studies reported controversial results about the independence of CKD as a risk factor for atherosclerosis. In this study, we tried to determine whether the estimated glomerular filtration rate (eGFR) and other renal function tests are independent factors associated with arterial stiffness in community-dwelling individuals with a normal (≥90) or slightly decreased eGFR (60-90). Materials and Methods: Data of 164 community individuals were analyzed, and demographic information, related disease history, atherosclerosis risk factors, certain laboratory tests, the estimated eGFR, and urine albumin creatinine ratio (UACR) were recorded for each individual. Results: The age, systolic blood pressure (SBP), hypertension (HTN), and cardio-ankle vascular index (CAVI) significantly differed between individuals with a normal and those with a slightly decreased eGFR. Blood urea nitrogen (BUN), glycated hemoglobin (HBA1c), and the eGFR significantly differed between the high- and low-CAVI groups and were also significantly correlated with the CAVI. The relationship between the eGFR and CAVI was shown to be independent of other atherosclerosis risk factors in a multiple linear regression model. Conclusions: We concluded that evaluations of the eGFR, HTN, body-mass index, and SBP can be used in a model for arterial stiffness risk assessments for community-dwelling individuals with a normal or slightly decreased eGFR.

Activation of IGF-I Survival Signaling and Its Compensative Inhibition of the Cardiac Apoptosis on Carotid Arteries Balloon-Injured Rat Hearts.

In this study, a rat carotid balloon injury-animal model was used to elucidate the temporal relation of hypertrophy in the progression of cardiac damage and the role of insulin-like growth factor (IGF)-I survival pathway on course of the cardiac damage. Rats were subjected to carotid balloon-injury and examined at different time points. We further studied the heart-weight/body-weight-ratio, histology and protein expression to understand the pathological events associated with percutaneous transluminal coronary angioplasty (PTCA) induced damages. Protein expression analysis showed increased levels of IGF-I signaling pathway and mitogen-activated protein kinase (MAPK) signaling pathway after 2 h and after 2 d of carotid balloon injury. On the other hand, apoptosis signaling pathways were enhanced after 14 d of carotid balloon injury. According to the results, rat carotid balloon injury significantly induced IGF-I survival signaling and compensated hypertrophy pathway during the initial period of injury however after 14 d the proteins involved in apoptotic cell death were elevated and the proteins of the survival pathway and compensatory hypertrophy were significantly reduced.

[Geographic spatial pattern of digestive system cancers in Yiwu city].

OBJECTIVE: To analyze the geographic spatial patterns and risk areas of main digestive system cancers in Yiwu city. METHODS: Newly diagnosed cases of esophageal, gastric and colorectal cancer during 2010-2014 were obtained from Yiwu Center for Disease Control and Prevention (CDC). The household registration population data in 2013 were obtained from public security bureau. Hierarchy clustering and partitioning regionalization method was used to generate geographic units. Global Moran's I was used to evaluate whether cancer incidence was significantly clustered in space, Anselin Local Moran's I was used to identify statistically significant hot spots, cold spots, and spatial outliers, and Spatial Scan Statistics was implemented to analyze the relative risk of cancers in different areas. RESULTS: The 5-year average incidence of esophageal, gastric and colorectal cancers were 9.99/100 000, 34.01/100 000 and 31.46/100 000, respectively. Males showed significantly higher incidence than females. The incidence was heterogeneous throughout the study area. Spatial Scan analysis revealed that southern Yiwu presented a significantly higher male esophageal cancer (RR=1.78) and gastric cancer (RR=1.87) risk. The central area of Yiwu showed a significantly lower female esophageal cancer risk (RR=0.00) and male stomach cancer risk (RR=0.63) and the northern Yiwu exhibited a significantly lower female colorectal cancer risk (RR=0.48). CONCLUSIONS: The incidence of main digestive tract cancers shows a heterogeneous distribution in Yiwu city.

Secondhand Smoke Exposure Enhances Cardiac Fibrosis Effects on the Aging Rat Hearts.

BACKGROUND: Examining aging rats exposed to secondhand smoke (SHS) engenders changes in left ventricular remodeling due to age- or disease-dependent alterations. METHODS: Rats were placed in whole-body exposure chambers and exposed to 10 cigarettes. Filtered air was introduced into the chamber at a low rate. Rats were exposed to SHS for 30 min, twice a day, 5 days per week for 1 month. After 4 weeks SHS exposure, rats were sacrificed for morphological study with trichome staining and left ventricular remodeling related protein analysis using western blot. RESULTS: Characteristic fibrotic morphology in the left ventricle increased significantly with aging and exposure to SHS. Exposure to SHS elevated TGFß1/p-Smad2/3/CTGF and MMP2/MMP9 protein expression levels (p < 0.05). No significant differences in FGF-2 and UPA protein expression were noted as a result of SHS exposure. However, TIMP-1, TIMP-2, TIMP-3 and TIMP-4 protein expression were suppressed by SHS exposure. We also observed increased TGFß1/p-Smad2/3/CTGF (p < 0.01), FGF-2/UPA (p < 0.05) and decreased TIMPs protein expression levels. Corresponding MMP2 and MMP9 upregulation occurred with aging and exposure to SHS. TGFß1/p-Smad2/3/CTGF and FGF-2/UPA protein expression from SHS exposure were higher than that from aging. In contrast, MMP2 and MMP9 were increased in aging rats compared with SHS exposed rats (p < 0.05); however, TIMP-1 (p < 0.01), TIMP-2 (p < 0.01) and TIMP-3 (p < 0.05) were decreased. TIMP-4 protein expression levels were decreased compared with SHS exposed rats (p < 0.01). CONCLUSIONS: Aging and SHS exposure in rats will produce elevated fibrosis. Exposure to SHS will accelerate aging and left ventricular fibrosis.

Secondhand Smoke Exposure Reduced the Compensatory Effects of IGF-I Growth Signaling in the Aging Rat Hearts.

BACKGROUND: Secondhand smoke (SHS) exposure is associated with increased risk of cardiovascular disease. Aging is a physiological process that involves progressive impairment of normal heart functions due to increased vulnerability to damage. This study examines secondhand smoke exposure in aging rats to determine the age-related death-survival balance. METHODS: Rats were placed into a SHS exposure chamber and exposed to smog. Old age male Sprague-Dawley rats were exposed to 10 cigarettes for 30 min, day and night, continuing for one week. After 4 weeks the rats underwent morphological and functional studies. Left ventricular sections were stained with hematoxylin-eosin for histopathological examination. TUNEL detected apoptosis cells and protein expression related death and survival pathway were analyzed using western blot. RESULTS: Death receptor-dependent apoptosis upregulation pathways and the mitochondria apoptosis proteins were apparent in young SHS exposure and old age rats. These biological markers were enhanced in aging SHS-exposed rats. The survival pathway was found to exhibit compensation only in young SHS-exposed rats, but not in the aging rats. Further decrease in the activity of this pathway was observed in aging SHS-exposed rats. TUNEL apoptotic positive cells were increased in young SHS-exposed rats, and in aging rats with or without SHS-exposure. CONCLUSIONS: Aging reduces IGF-I compensated signaling with accelerated cardiac apoptotic effects from second-hand smoke.

Hepatoprotective Effects of Traditional Chinese Medicine on Liver Fibrosis from Ethanol Administration following Partial Hepatectomy.

The aim of this study was to establish the effective hepatoprotective properties of traditional Chinese medicines (TCMs) in fibrotic rat liver regeneration after partial hepatectomy (PHx). Fibrosis was induced in rats by ethanol (EtOH, 5 ml/kg) administration for 6, 24, 72, and 168 h. The rats were then fed four TCMs (1 g/kg/day, Codonopsis pilosula (CP), Salvia miltorrhiza Bunge (SMB), Bupleurum kasi (BK), and Elephantopus scaber L (ESL)) to Spraque-Dawley rats for 6, 24, 72 and 168 h, respectively. Surgical 70% cirrhotic fibrosis PHx was then conducted at 6, 24, 72, and 168 h. The effects on liver regeneration were examined to estimate and measure hepatocyte growth factor (HGF), focal adhesion kinase (FAK), Cyclin D1, Cyclin E, and retinoblastoma protein (pRb) protein expression using Western blotting analysis. Cyclin D1, matrix metalloproteinase (MMP)-2, MMP-9, tissue inhibitors of metalloproteinase (TIMP)-1, TIMP-2 and TIMP-3 mRNA by Reverse transcription polymerase chain reaction (RT-PCR) were analyzed in cirrhotic fibrosis rats. Transforming growth factor-ß1 (TGF-ß1), Cyclin D1, Cyclin E, pRb and E2F mRNA expression levels were determined in fibrotic rats following PHx using RT-PCR. We found elevated glutamyl oxaloacetic transaminase (GOT), glutamyl pyrubic transaminase (GPT), alkaline phosphatase (ALP), gammaglutamyl transpeptidase (γ-GT), glutathione (GSH), nonprotein sulfhydryl (NPSH) and total bilirubin in serum after 6 h EtOH administration. These levels were progressively decreased over 168 h. Total protein and albumin were reduced in serum after 6 h administration and then progressively increased. In contrast, tissues disorder histology and morphology were determined in liver sections. After rats were fed TCMs we found that SMB extraction not only induced HGF, FAK, Cyclin D1, and pRb protein expression and Cyclin D1 mRNA increases, but also reduced MMP-2 and MMP-9 after 24 and 72 h post injury. In the cell cycle S phase the Cyclin E protein expression was increased by ESL. CP induced TIMP-1, TIMP-2 and TIMP-3 mRNA increases in fibrotic rats. We detected liver regeneration in fibrotic rats. We also found that the liver regeneration index increased from 6 to 168 h post PHx. After 168 h fibrotic liver regeneration rats exhibited reduced TGF-ß1 mRNA expression and enhanced Cyclin D1, Cyclin E, pRb and E2F mRNA expression. TCMs play a crucial role in the early mediating process in fibrotic rat liver regeneration after PHx.

Structural and functional analysis of the related transcriptional enhancer factor-1 and NF-κB interaction.

The related transcriptional enhancer factor-1 (RTEF-1) increases gene transcription of hypoxia-inducible factor 1α (HIF-1α) and enhances angiogenesis in endothelium. Both hypoxia and inflammatory factor TNF-α regulate gene expression of HIF-1α, but how RTEF-1 and TNF-α coordinately regulate HIF-1α gene transcription is unclear. Here, we found that RTEF-1 interacts with p65 subunit of NF-κB, a primary mediator of TNF-α. RTEF-1 increased HIF-1α promoter activity, whereas expression of p65 subunit inhibited the stimulatory effect. By contrast, knockdown of p65 markedly enhanced RTEF-1 stimulation on the HIF-1α promoter activity (7-fold). A physical interaction between RTEF-1 and p65 was confirmed by coimmunoprecipitation experiments in cells and glutathione S-transferase (GST)-pull-down assays. A computational analysis of RTEF-1 crystal structures revealed that a conserved surface of RTEF-1 potentially interacts with p65 via four amino acid residues located at T347, Y349, R351, and Y352. We performed site-directed mutagenesis and GST-pull-down assays and demonstrated that Tyr352 (Y352) in RTEF-1 is a key site for the formation of RTEF-1 and p65-NF-κB complex. An alanine mutation at Y352 of RTEF-1 disrupted the interaction of RTEF-1 with p65. Moreover, expression of RTEF-1 decreased TNF-α-induced HIF-1α promoter activity, IL-1ß, and IL-6 mRNA levels in cells; however, the effect of RTEF-1 was largely lost when Y352 was mutated to alanine. These results indicate that RTEF-1 interacts with p65-NF-κB through Y352 and that they antagonize each other for HIF-1α transcriptional activation, suggesting a novel mechanism by which RTEF-1 regulates gene expression, linking hypoxia to inflammation.

RTEF-1 attenuates blood glucose levels by regulating insulin-like growth factor binding protein-1 in the endothelium.

RATIONALE: Related transcriptional enhancer factor-1 (RTEF-1) plays an important role in endothelial cell function by regulating angiogenesis; however, the mechanism underlying the role of RTEF-1 in the endothelium in vivo is not well defined. OBJECTIVE: We investigated the biological functions of RTEF-1 by disrupting the gene that encodes it in mice endothelium -specific RTEF-1-deficient transgenic mice (RTEF-1(-/-)). METHODS AND RESULTS: RTEF-1(-/-) mice showed significantly increased blood glucose levels and insulin resistance, accompanied by decreased levels of insulin-like growth factor binding protein-1 (IGFBP-1) mRNA in the endothelium and decreased serum IGFBP-1 levels. Additionally, the RTEF-1(-/-) phenotype was exacerbated when the mice were fed a high-fat diet, which correlated with decreased IGFBP-1 levels. In contrast, vascular endothelial cadherin/RTEF-1-overexpressing(1) transgenic mice (VE-Cad/RTEF1) demonstrated improved glucose clearance and insulin sensitivity in response to a high-fat diet. Furthermore, we demonstrated that RTEF-1 upregulates IGFBP-1 through selective binding and promotion of transcription from the insulin response element site. Insulin prevented RTEF-1 expression and significantly inhibited IGFBP-1 transcription in endothelial cells in a dose-dependent fashion. CONCLUSIONS: To the best of our knowledge, this is the first report demonstrating that RTEF-1 stimulates promoter activity through an insulin response element and also mediates the effects of insulin on gene expression. These results show that RTEF-1-stimulated IGFBP-1 expression may be central to the mechanism by which RTEF-1 attenuates blood glucose levels. These findings provide the basis for novel insights into the transcriptional regulation of IGFBP-1 and contribute to our understanding of the role of vascular endothelial cells in metabolism.

Secondhand smoke exposure toxicity accelerates age-related cardiac disease in old hamsters.

BACKGROUND: Aging is associated with physiological or pathological left ventricular hypertrophy (LVH) cardiac changes. Secondhand smoke (SHS) exposure is associated with pathological LVH. The action mechanism in cardiac concentric hypertrophy from SHS exposure is understood, but the transition contributed from SHS exposure is not. To determine whether exposure to SHS has an impact on age-induced LVH we examined young and old hamsters that underwent SHS exposure in a chamber for 30 mins. METHODS: Morphological and histological studies were then conducted using hematoxylin and eosin (H&E) and Masson's trichrome staining. Echocardiographic analysis was used to determine left ventricular wall thickness and function. LVH related protein expression levels were detected by western blot analysis. RESULTS: The results showed that both young and aged hamsters exposed to SHS exhibited increased heart weights and left ventricular weights, left ventricular posterior wall thickness and intraventricular septum systolic and diastolic pressure also increased. However, left ventricular function systolic and diastolic pressure deteriorated. H&E and Masson's trichrome staining results showed LV papillary muscles were ruptured, resulting in lower cardiac function at the myocardial level. LV muscle fiber arrangement was disordered and collagen accumulation occurred. Concentric LVH related protein molecular markers increased only in young hamsters exposed to SHS. However, this declined with hamster age. By contrast, eccentric LVH related proteins increased in aging hamsters exposed the SHS. Pro-inflammatory proteins, IL-6, TNF-α, JAK1, STAT3, and SIRTI expression increased in aging hamsters exposed to SHS. CONCLUSIONS: We suggest that SHS exposure induces a pro-inflammatory response that results in concentric transition to aging eccentric LVH.