共查询到20条相似文献,搜索用时 15 毫秒
1.
Objectives
Anthrax infection is associated with devastating cardiovascular sequelae, suggesting unfavorable cardiovascular effects of toxins originated from Bacillus anthracis namely lethal and edema toxins. This study was designed to examine the direct effect of lethal toxins on cardiomyocyte contractile and intracellular Ca2+ properties.Methods
Murine cardiomyocyte contractile function and intracellular Ca2+ handling were evaluated including peak shortening (PS), maximal velocity of shortening/ relengthening (± dL/dt), time-to-PS (TPS), time-to-90% relengthening (TR90), intracellular Ca2+ rise measured as fura-2 fluorescent intensity (ΔFFI), and intracellular Ca2+ decay rate. Stress signaling and Ca2+ regulatory proteins were assessed using Western blot analysis.Results
In vitro exposure to a lethal toxin (0.05 – 50 nM) elicited a concentration-dependent depression on cardiomyocyte contractile and intracellular Ca2+ properties (PS, ± dL/dt, ΔFFI), along with prolonged duration of contraction and intracellular Ca2+ decay, the effects of which were nullified by the NADPH oxidase inhibitor apocynin. The lethal toxin significantly enhanced superoxide production and cell death, which were reversed by apocynin. In vivo lethal toxin exposure exerted similar time-dependent cardiomyocyte mechanical and intracellular Ca2+ responses. Stress signaling cascades including MEK1/2, p38, ERK and JNK were unaffected by in vitro lethal toxins whereas they were significantly altered by in vivo lethal toxins. Ca2+ regulatory proteins SERCA2a and phospholamban were also differentially regulated by in vitro and in vivo lethal toxins. Autophagy was drastically triggered although ER stress was minimally affected following lethal toxin exposure.Conclusions
Our findings indicate that lethal toxins directly compromised murine cardiomyocyte contractile function and intracellular Ca2+ through a NADPH oxidase-dependent mechanism. 相似文献2.
Objectives
Binge drinking and alcohol toxicity are often associated with myocardial dysfunction possibly due to accumulation of the ethanol metabolite acetaldehyde although the underlying mechanism is unknown. This study was designed to examine the impact of accelerated ethanol metabolism on myocardial contractility, mitochondrial function and apoptosis using a murine model of cardiac-specific overexpression of alcohol dehydrogenase (ADH).Methods
ADH and wild-type FVB mice were acutely challenged with ethanol (3 g/kg/d, i.p.) for 3 days. Myocardial contractility, mitochondrial damage and apoptosis (death receptor and mitochondrial pathways) were examined.Results
Ethanol led to reduced cardiac contractility, enlarged cardiomyocyte, mitochondrial damage and apoptosis, the effects of which were exaggerated by ADH transgene. In particular, ADH exacerbated mitochondrial dysfunction manifested as decreased mitochondrial membrane potential and accumulation of mitochondrial O2 •−. Myocardium from ethanol-treated mice displayed enhanced Bax, Caspase-3 and decreased Bcl-2 expression, the effect of which with the exception of Caspase-3 was augmented by ADH. ADH accentuated ethanol-induced increase in the mitochondrial death domain components pro-caspase-9 and cytochrome C in the cytoplasm. Neither ethanol nor ADH affected the expression of ANP, total pro-caspase-9, cytosolic and total pro-caspase-8, TNF-α, Fas receptor, Fas L and cytosolic AIF.Conclusions
Taken together, these data suggest that enhanced acetaldehyde production through ADH overexpression following acute ethanol exposure exacerbated ethanol-induced myocardial contractile dysfunction, cardiomyocyte enlargement, mitochondrial damage and apoptosis, indicating a pivotal role of ADH in ethanol-induced cardiac dysfunction possibly through mitochondrial death pathway of apoptosis. 相似文献3.
Objectives
Binge alcohol drinking often triggers myocardial contractile dysfunction although the underlying mechanism is not fully clear. This study was designed to examine the impact of cardiac-specific overexpression of alcohol dehydrogenase (ADH) on ethanol-induced change in cardiac contractile function, intracellular Ca2+ homeostasis, insulin and AMP-dependent kinase (AMPK) signaling.Methods
ADH transgenic and wild-type FVB mice were acutely challenged with ethanol (3 g/kg/d, i.p.) for 3 days. Oral glucose tolerance test, cardiac AMP/ATP levels, cardiac contractile function, intracellular Ca2+ handling and AMPK signaling (including ACC and LKB1) were examined.Results
Ethanol exposure led to glucose intolerance, elevated plasma insulin, compromised cardiac contractile and intracellular Ca2+ properties, downregulated protein phosphatase PP2A subunit and PPAR-γ, as well as phosphorylation of AMPK, ACC and LKB1, all of which except plasma insulin were overtly accentuated by ADH transgene. Interestingly, myocardium from ethanol-treated FVB mice displayed enhanced expression of PP2Cα and PGC-1α, decreased insulin receptor expression as well as unchanged expression of Glut4, the response of which was unaffected by ADH. Cardiac AMP-to-ATP ratio was significantly enhanced by ethanol exposure with a more pronounced increase in ADH mice. In addition, the AMPK inhibitor compound C (10 µM) abrogated acute ethanol exposure-elicited cardiomyocyte mechanical dysfunction.Conclusions
In summary, these data suggest that the ADH transgene exacerbated acute ethanol toxicity-induced myocardial contractile dysfunction, intracellular Ca2+ mishandling and glucose intolerance, indicating a role of ADH in acute ethanol toxicity-induced cardiac dysfunction possibly related to altered cellular fuel AMPK signaling cascade. 相似文献4.
Objective
Mitochondrial oxidative stress is the basis for pancreatic β-cell apoptosis and a common pathway for numerous types of damage, including glucotoxicity and lipotoxicity. We cultivated mice pancreatic β-cell tumor Min6 cell lines in vitro and observed pancreatic β-cell apoptosis and changes in mitochondrial function before and after the addition of Exendin-4. Based on these observations, we discuss the protective role of Exendin-4 against mitochondrial oxidative damage and its relationship with Ca2+-independent phospholipase A2.Methods
We established a pancreatic β-cell oxidative stress damage model using Min6 cell lines cultured in vitro with tert-buty1 hydroperoxide and hydrogen peroxide. We then added Exendin-4 to observe changes in the rate of cell apoptosis (Annexin-V-FITC-PI staining flow cytometry and DNA ladder). We detected the activity of the caspase 3 and 8 apoptotic factors, measured the mitochondrial membrane potential losses and reactive oxygen species production levels, and detected the expression of cytochrome c and Smac/DLAMO in the cytosol and mitochondria, mitochondrial Ca2-independent phospholipase A2 and Ca2+-independent phospholipase A2 mRNA.Results
The time-concentration curve showed that different percentages of apoptosis occurred at different time-concentrations in tert-buty1 hydroperoxide- and hydrogen peroxide-induced Min6 cells. Incubation with 100 µmol/l of Exendin-4 for 48 hours reduced the Min6 cell apoptosis rate (p<0.05). The mitochondrial membrane potential loss and total reactive oxygen species levels decreased (p<0.05), and the release of cytochrome c and Smac/DLAMO from the mitochondria was reduced. The study also showed that Ca2+-independent phospholipase A2 activity was positively related to Exendin-4 activity.Conclusion
Exendin-4 reduces Min6 cell oxidative damage and the cell apoptosis rate, which may be related to Ca2-independent phospholipase A2. 相似文献5.
《Free radical research》2013,47(10):1187-1198
AbstractAims. Endoplasmic reticulum (ER) stress exerts myocardial oxidative stress, apoptosis, and contractile anomalies, although the precise interplay between ER stress and apoptosis remains elusive. This study was designed to examine the impact of the cysteine-rich free radical scavenger metallothionein on ER stress-induced myocardial contractile defect and underlying mechanisms. Methods and results. Wild-type friendly virus B and transgenic mice with cardiac-specific overexpression of metallothionein were challenged with the ER stress inducer tunicamycin (1 mg/kg, intraperitoneal, 48 h) prior to the assessment of myocardial function, oxidative stress, and apoptosis. Our results revealed that tunicamycin promoted cardiac remodeling (enlarged left ventricular end systolic/diastolic diameters with little changes in left ventricular wall thickness), suppressed fractional shortening and cardiomyocyte contractile function, elevated resting Ca2+, decreased stimulated Ca2+ release, prolonged intracellular Ca2+ clearance, and downregulated sarco(endo)plasmic reticulum Ca2+-ATPase levels, the effects of which were negated by metallothionein. Treatment with tunicamycin caused cardiomyocyte mitochondrial injury, as evidenced by decreased mitochondrial membrane potential (??m, assessed by JC-1 staining), the effect of which was negated by the antioxidant. Moreover, tunicamycin challenge dramatically facilitated myocardial apoptosis as manifested by increased Bax, caspase 9, and caspase 12 protein levels, as well as elevated caspase 3 activity. Interestingly, metallothionein transgene significantly alleviated tunicamycin-induced myocardial apoptosis. Conclusion. Taken together, our data favor a beneficial effect of metallothionein against ER stress-induced cardiac dysfunction possibly associated with attenuation of myocardial apoptosis. 相似文献
6.
Background
Sidestream smoke is closely associated with airway inflammation and hyperreactivity. The present study was designed to investigate if the Raf-1 inhibitor GW5074 and the anti-inflammatory drug dexamethasone suppress airway hyperreactivity in a mouse model of sidestream smoke exposure.Methods
Mice were repeatedly exposed to smoke from four cigarettes each day for four weeks. After the first week of the smoke exposure, the mice received either dexamethasone intraperitoneally every other day or GW5074 intraperitoneally every day for three weeks. The tone of the tracheal ring segments was recorded with a myograph system and concentration-response curves were obtained by cumulative administration of agonists. Histopathology was examined by light microscopy.Results
Four weeks of exposure to cigarette smoke significantly increased the mouse airway contractile response to carbachol, endothelin-1 and potassium. Intraperitoneal administration of GW5074 or dexamethasone significantly suppressed the enhanced airway contractile responses, while airway epithelium-dependent relaxation was not affected. In addition, the smoke-induced infiltration of inflammatory cells and mucous gland hypertrophy were attenuated by the administration of GW5074 or dexamethasone.Conclusion
Sidestream smoke induces airway contractile hyperresponsiveness. Inhibition of Raf-1 activity and airway inflammation suppresses smoking-associated airway hyperresponsiveness. 相似文献7.
Ryo Fukumori Takeshi Takarada Ryota Nakazato Koichi Fujikawa Miki Kou Eiichi Hinoi Yukio Yoneda 《PloS one》2013,8(7)
Background
We have shown the involvement of mitochondrial uncoupling protein-2 (UCP2) in the cytotoxicity by N-methyl-D-aspartate receptor (NMDAR) through a mechanism relevant to the increased mitochondrial Ca2+ levels in HEK293 cells with acquired NMDAR channels. Here, we evaluated pharmacological profiles of ethanol on the NMDA-induced increase in mitochondrial Ca2+ levels in cultured murine neocortical neurons.Methodology/Principal Findings
In neurons exposed to glutamate or NMDA, a significant increase was seen in mitochondrial Ca2+ levels determined by Rhod-2 at concentrations of 0.1 to 100 µM. Further addition of 250 mM ethanol significantly inhibited the increase by glutamate and NMDA in Rhod-2 fluorescence, while similarly potent inhibition of the NMDA-induced increase was seen after exposure to ethanol at 50 to 250 mM in cultured neurons. Lentiviral overexpression of UCP2 significantly accelerated the increase by NMDA in Rhod-2 fluorescence in neurons, without affecting Fluo-3 fluorescence for intracellular Ca2+ levels. In neurons overexpressing UCP2, exposure to ethanol resulted in significantly more effective inhibition of the NMDA-induced increase in mitochondrial free Ca2+ levels than in those without UCP2 overexpression, despite a similarly efficient increase in intracellular Ca2+ levels irrespective of UCP2 overexpression. Overexpression of UCP2 significantly increased the number of dead cells in a manner prevented by ethanol in neurons exposed to glutamate. In HEK293 cells with NMDAR containing GluN2B subunit, more efficient inhibition was similarly induced by ethanol at 50 and 250 mM on the NMDA-induced increase in mitochondrial Ca2+ levels than in those with GluN2A subunit. Decreased protein levels of GluN2B, but not GluN2A, subunit were seen in immunoprecipitates with UCP2 from neurons with brief exposure to ethanol at concentrations over 50 mM.Conclusions/Significance
Ethanol could inhibit the interaction between UCP2 and NMDAR channels to prevent the mitochondrial Ca2+ incorporation and cell death after NMDAR activation in neurons. 相似文献8.
Yu-Fan Hsieh Guang-Yaw Liu Yi-Ju Lee Jiann-Jou Yang Katalin Sándor Zsolt Sarang Angela Bononi Paolo Pinton László Tretter Zsuzsa Szondy Gregory J. Tsay 《PloS one》2013,8(12)
Background
Transglutaminase 2 (TG2) is a protein cross-linking enzyme known to be associated with the in vivo apoptosis program of T cells. However, its role in the T cell apoptosis program was not investigated yet.Results
Here we report that timed overexpression of both the wild type (wt) and the cross-linking mutant of TG2 induced apoptosis in Jurkat T cells, the wt being more effective. Part of TG2 colocalised with mitochondria. WtTG2-induced apoptosis was characterized by enhanced mitochondrial Ca2+ uptake. Ca2+-activated wtTG2 cross-linked RAP1, GTP-GDP dissociation stimulator 1, an unusual guanine exchange factor acting on various small GTPases, to induce a yet uncharacterized signaling pathway that was able to promote the Ca2+ release from the endoplasmic reticulum via both Ins3P and ryanodine sensitive receptors leading to a consequently enhanced mitochondrial Ca2+uptake.Conclusions
Our data indicate that TG2 might act as a Ca2+ sensor to amplify endoplasmic reticulum-derived Ca2+ signals to enhance mitochondria Ca2+ uptake. Since enhanced mitochondrial Ca2+ levels were previously shown to sensitize mitochondria for various apoptotic signals, our data demonstrate a novel mechanism through which TG2 can contribute to the induction of apoptosis in certain cell types. Since, as compared to knock out cells, physiological levels of TG2 affected Ca2+ signals in mouse embryonic fibroblasts similar to Jurkat cells, our data might indicate a more general role of TG2 in the regulation of mitochondrial Ca2+ homeostasis. 相似文献9.
Xiangde Liu Shinsaku Togo Mona Al-Mugotir Huijung Kim QiuHong Fang Tetsu Kobayashi XingQi Wang Lijun Mao Peter Bitterman Stephen Rennard 《Respiratory research》2008,9(1):66
Background
We have previously reported that low concentrations of cigarette smoke extract induce DNA damage without leading to apoptosis or necrosis in human bronchial epithelial cells (HBECs), and that IL-6/STAT3 signaling contributes to the cell survival. Since NF-κB is also involved in regulating apoptosis and cell survival, the current study was designed to investigate the role of NF-κB in mediating cell survival in response to cigarette smoke exposure in HBECs.Methods
Both the pharmacologic inhibitor of NF-κB, curcumin, and RNA interference targeting p65 were used to block NF-κB signaling in HBECs. Apoptosis and cell survival were then assessed by various methods including COMET assay, LIVE/DEAD Cytotoxicity/Viability assay and colony formation assay.Results
Cigarette smoke extract (CSE) caused DNA damage and cell cycle arrest in S phase without leading to apoptosis in HBECs as evidenced by TUNEL assay, COMET assay and DNA content assay. CSE stimulated NF-κB -DNA binding activity and up-regulated Bcl-XL protein in HBECs. Inhibition of NF-κB by the pharmacologic inhibitor curcumin (20 μM) or suppression of p65 by siRNA resulted in a significant increase in cell death in response to cigarette smoke exposure. Furthermore, cells lacking p65 were incapable of forming cellular colonies when these cells were exposed to CSE, while they behaved normally in the regular culture medium.Conclusion
The current study demonstrates that CSE activates NF-κB and up-regulates Bcl-XL through NF-kB activation in HBECs, and that CSE induces cell death in cells lacking p65. These results suggest that activation of NF-κB regulates cell survival following DNA damage by cigarette smoke in human bronchial epithelial cells. 相似文献10.
ER stress triggers myocardial contractile dysfunction although the underlying mechanism is still elusive. Given that NADPH oxidase was recently implicated in ER stress-induced tissue injury, this study was designed to examine the role of NADPH oxidase in ER stress-induced cardiac mechanical defects and the impact of Akt activation on ER stress-induced cardiac anomalies. Wild-type and transgenic mice with cardiac-specific overexpression of an active mutant of Akt (MyAkt) were subjected to the ER stress inducer thapsigargin (1 and 3 mg/kg, ip, for 48 h). Thapsigargin compromised echocardiographic parameters, including elevating LVESD and reducing fractional shortening; suppressed cardiomyocyte contractile function, intracellular Ca2+ handling, and cell survival; and enhanced carbonyl formation, apoptosis, superoxide production, NADPH oxidase expression, and mitochondrial damage. Interestingly, these anomalies were attenuated or mitigated by chronic Akt activation. Treatment with thapsigargin also dephosphorylated Akt and its downstream signal GSK3β (leading to activation of GSK3β), the effect of which was abrogated in MyAkt hearts. Knockdown of the cytosolic subunit of NADPH oxidase, p47phox, using siRNA abrogated thapsigargin-induced apoptosis and cell death in H9C2 myoblasts. In vitro exposure to thapsigargin induced murine cardiomyocyte dysfunction reminiscent of the in vivo setting, the effects of which were ablated by the NADPH oxidase inhibitor apocynin and the mitochondrial Ca2+ uptake inhibitor Ru360. In addition, apocynin abrogated thapsigargin-induced loss of mitochondrial membrane potential and permeability transition pore opening, similar to chronic Akt activation. In summary, these data suggest that ER stress interrupts cardiac contractile and intracellular Ca2+ homeostasis, cell survival, and mitochondrial integrity through an Akt dephosphorylation- and NADPH oxidase-dependent mechanism. 相似文献
11.
Marc-André Caron Mathieu C. Morissette Marie-Eve Thériault Jake K. Nikota Martin R. St?mpfli Richard Debigaré 《PloS one》2013,8(6)
Background
Skeletal muscle dysfunction is common in chronic obstructive pulmonary disease (COPD), a disease mainly caused by chronic cigarette use. An important proportion of patients with COPD have decreased muscle mass, suggesting that chronic cigarette smoke exposure may interfere with skeletal muscle cellular equilibrium. Therefore, the main objective of this study was to investigate the kinetic of the effects that cigarette smoke exposure has on skeletal muscle cell signaling involved in protein homeostasis and to assess the reversibility of these effects.Methods
A mouse model of cigarette smoke exposure was used to assess skeletal muscle changes. BALB/c mice were exposed to cigarette smoke or room air for 8 weeks, 24 weeks or 24 weeks followed by 60 days of cessation. The gastrocnemius and soleus muscles were collected and the activation state of key mediators involved in protein synthesis and degradation was assessed.Results
Gastrocnemius and soleus were smaller in mice exposed to cigarette smoke for 8 and 24 weeks compared to room air exposed animals. Pro-degradation proteins were induced at the mRNA level after 8 and 24 weeks. Twenty-four weeks of cigarette smoke exposure induced pro-degradation proteins and reduced Akt phosphorylation and glycogen synthase kinase-3β quantity. A 60-day smoking cessation period reversed the cell signaling alterations induced by cigarette smoke exposure.Conclusions
Repeated cigarette smoke exposure induces reversible muscle signaling alterations that are dependent on the duration of the cigarette smoke exposure. These results highlights a beneficial aspect associated with smoking cessation. 相似文献12.
Jun Li Xuesong Ma Wei Yu Zhangqun Lou Dunlan Mu Ying Wang Baozhong Shen Sihua Qi 《PloS one》2012,7(9)
Background and Purpose
Mitochondrial dysfunction has been implicated in the cell death observed after cerebral ischemia, and several mechanisms for this dysfunction have been proposed. Reperfusion after transient cerebral ischemia may cause continued and even more severe damage to the brain. Many lines of evidence have shown that mitochondria suffer severe damage in response to ischemic injury. The purpose of this study was to observe the features of mitochondrial dysfunction in isolated mitochondria during the reperfusion period following focal cerebral ischemia.Methods
Male Wistar rats were subjected to focal cerebral ischemia. Mitochondria were isolated using Percoll density gradient centrifugation. The isolated mitochondria were fixed for electron microscopic examination; calcium-induced mitochondrial swelling was quantified using spectrophotometry. Cyclophilin D was detected by Western blotting. Fluorescent probes were used to selectively stain mitochondria to measure their membrane potential and to measure reactive oxidative species production using flow cytometric analysis.Results
Signs of damage were observed in the mitochondrial morphology after exposure to reperfusion. The mitochondrial swelling induced by Ca2+ increased gradually with the increasing calcium concentration, and this tendency was exacerbated as the reperfusion time was extended. Cyclophilin D protein expression peaked after 24 hours of reperfusion. The mitochondrial membrane potential was decreased significantly during the reperfusion period, with the greatest decrease observed after 24 hours of reperfusion. The surge in mitochondrial reactive oxidative species occurred after 2 hours of reperfusion and was maintained at a high level during the reperfusion period.Conclusions
Reperfusion following focal cerebral ischemia induced significant mitochondrial morphological damage and Ca2+-induced mitochondrial swelling. The mechanism of this swelling may be mediated by the upregulation of the Cyclophilin D protein, the destruction of the mitochondrial membrane potential and the generation of excessive reactive oxidative species. 相似文献13.
Roland F Hoffmann Sina Zarrintan Simone M Brandenburg Arjan Kol Harold G de Bruin Shabnam Jafari Freark Dijk Dharamdajal Kalicharan Marco Kelders Harry R Gosker Nick HT ten Hacken Johannes J van der Want Antoon JM van Oosterhout Irene H Heijink 《Respiratory research》2013,14(1):97
Background
Cigarette smoking is the major risk factor for COPD, leading to chronic airway inflammation. We hypothesized that cigarette smoke induces structural and functional changes of airway epithelial mitochondria, with important implications for lung inflammation and COPD pathogenesis.Methods
We studied changes in mitochondrial morphology and in expression of markers for mitochondrial capacity, damage/biogenesis and fission/fusion in the human bronchial epithelial cell line BEAS-2B upon 6-months from ex-smoking COPD GOLD stage IV patients to age-matched smoking and never-smoking controls.Results
We observed that long-term CSE exposure induces robust changes in mitochondrial structure, including fragmentation, branching and quantity of cristae. The majority of these changes were persistent upon CSE depletion. Furthermore, long-term CSE exposure significantly increased the expression of specific fission/fusion markers (Fis1, Mfn1, Mfn2, Drp1 and Opa1), oxidative phosphorylation (OXPHOS) proteins (Complex II, III and V), and oxidative stress (Mn-SOD) markers. These changes were accompanied by increased levels of the pro-inflammatory mediators IL-6, IL-8, and IL-1β. Importantly, COPD primary bronchial epithelial cells (PBECs) displayed similar changes in mitochondrial morphology as observed in long-term CSE-exposure BEAS-2B cells. Moreover, expression of specific OXPHOS proteins was higher in PBECs from COPD patients than control smokers, as was the expression of mitochondrial stress marker PINK1.Conclusion
The observed mitochondrial changes in COPD epithelium are potentially the consequence of long-term exposure to cigarette smoke, leading to impaired mitochondrial function and may play a role in the pathogenesis of COPD. 相似文献14.
Chen ZH Kim HP Sciurba FC Lee SJ Feghali-Bostwick C Stolz DB Dhir R Landreneau RJ Schuchert MJ Yousem SA Nakahira K Pilewski JM Lee JS Zhang Y Ryter SW Choi AM 《PloS one》2008,3(10):e3316
Background
Chronic obstructive pulmonary disease (COPD) is a progressive lung disease characterized by abnormal cellular responses to cigarette smoke, resulting in tissue destruction and airflow limitation. Autophagy is a degradative process involving lysosomal turnover of cellular components, though its role in human diseases remains unclear.Methodology and Principal Findings
Increased autophagy was observed in lung tissue from COPD patients, as indicated by electron microscopic analysis, as well as by increased activation of autophagic proteins (microtubule-associated protein-1 light chain-3B, LC3B, Atg4, Atg5/12, Atg7). Cigarette smoke extract (CSE) is an established model for studying the effects of cigarette smoke exposure in vitro. In human pulmonary epithelial cells, exposure to CSE or histone deacetylase (HDAC) inhibitor rapidly induced autophagy. CSE decreased HDAC activity, resulting in increased binding of early growth response-1 (Egr-1) and E2F factors to the autophagy gene LC3B promoter, and increased LC3B expression. Knockdown of E2F-4 or Egr-1 inhibited CSE-induced LC3B expression. Knockdown of Egr-1 also inhibited the expression of Atg4B, a critical factor for LC3B conversion. Inhibition of autophagy by LC3B-knockdown protected epithelial cells from CSE-induced apoptosis. Egr-1 −/− mice, which displayed basal airspace enlargement, resisted cigarette-smoke induced autophagy, apoptosis, and emphysema.Conclusions
We demonstrate a critical role for Egr-1 in promoting autophagy and apoptosis in response to cigarette smoke exposure in vitro and in vivo. The induction of autophagy at early stages of COPD progression suggests novel therapeutic targets for the treatment of cigarette smoke induced lung injury. 相似文献15.
Background
There is limited knowledge about atrial myocyte Ca2+ handling in the failing hearts. The aim of this study was to examine atrial myocyte contractile function and Ca2+ handling in rats with post-infarction heart failure (HF) and to examine whether aerobic interval training could reverse a potential dysfunction.Methods and results
Post-infarction HF was induced in Sprague Dawley rats by ligation of the left descending coronary artery. Atrial myocyte shortening was depressed (p<0.01) and time to relaxation was prolonged (p<0.01) in sedentary HF-rats compared to healthy controls. This was associated with decreased Ca2+ amplitude, decreased SR Ca2+ content, and slower Ca2+ transient decay. Atrial myocytes from HF-rats had reduced sarcoplasmic reticulum Ca2+ ATPase activity, increased Na+/Ca2+-exchanger activity and increased diastolic Ca2+ leak through ryanodine receptors. High intensity aerobic interval training in HF-rats restored atrial myocyte contractile function and reversed changes in atrial Ca2+ handling in HF.Conclusion
Post infarction HF in rats causes profound impairment in atrial myocyte contractile function and Ca2+ handling. The observed dysfunction in atrial myocytes was partly reversed after aerobic interval training. 相似文献16.
Lei Xu Yuqin Chen Kai Yang Yingfeng Wang Lichun Tian Jie Zhang Elizabeth Wenqian Wang Dejun Sun Wenju Lu Jian Wang 《PloS one》2014,9(11)
Background
Hypoxia causes remodeling and contractile responses in both pulmonary artery (PA) and pulmonary vein (PV). Here we explore the effect of hypoxia on PV and pulmonary venous smooth muscle cells (PVSMCs).Methods
Chronic hypoxic pulmonary hypertension (CHPH) model was established by exposing rats to 10% O2 for 21 days. Rat distal PVSMCs were isolated and cultured for in vitro experiments. The fura-2 based fluorescence calcium imaging was used to measure the basal intracellular Ca2+ concentration ([Ca2+]i) and store-operated Ca2+ entry (SOCE). Quantitative RT-PCR and western blotting were performed to measure the expression of mRNA and levels of canonical transient receptor potential (TRPC) protein respectively.Results
Hypoxia increased the basal [Ca2+]i and SOCE in both freshly dissociated and serum cultured distal PVSMCs. Moreover, hypoxia increased TRPC6 expression at mRNA and protein levels in both cultured PVSMCs exposed to prolonged hypoxia (4% O2, 60 h) and distal PV isolated from CHPH rats. Hypoxia also enhanced proliferation and migration of rat distal PVSMCs.Conclusions
Hypoxia induces elevation of SOCE in distal PVSMCs, leading to enhancement of basal [Ca2+]i in PVSMCs. This enhancement is potentially correlated with the increased expression of TRPC6. Hypoxia triggered intracellular calcium contributes to promoted proliferation and migration of PVSMCs. 相似文献17.
Lifang Yang Jipeng Ma Ying Tan Qijun Zheng Maolong Dong Wei Guo Lize Xiong Jian Yang Jun Ren 《Journal of cellular and molecular medicine》2019,23(7):4640-4652
Hypertension contributes to the high cardiac morbidity and mortality. Although oxidative stress plays an essential role in hypertensive heart diseases, the mechanism remains elusive. Transgenic mice with cardiac overexpression of metallothionein, a heavy metal‐binding scavenger, were challenged with NG‐nitro‐L‐arginine methyl ester (L‐NAME) for 14 days prior to measurement of myocardial contractile and intracellular Ca2+ anomalies as well as cell signalling mechanisms using Western blot and immunofluorescence analysis. L‐NAME challenge elicited hypertension, macrophage infiltration, oxidative stress, inflammation and cardiac dysfunction manifested as increased proinflammatory macrophage marker F4/80, interleukin‐1β (IL‐1β), intracellular production, LV end systolic and diastolic diameters as well as depressed fractional shortening. L‐NAME treatment reduced mitochondrial membrane potential (MMP), impaired cardiomyocyte contractile and intracellular Ca2+ properties as evidenced by suppressed peak shortening, maximal velocity of shortening/relengthening, rise in intracellular Ca2+, along with elevated baseline and peak intracellular Ca2+. These unfavourable mechanical changes and decreased MMP (except blood pressure and macrophage infiltration) were alleviated by overexpression of metallothionein. Furthermore, the apoptosis markers including BAD, Bax, Caspase 9, Caspase 12 and cleaved Caspase 3 were up‐regulated while the anti‐apoptotic marker Bcl‐2 was decreased by L‐NAME treatment. Metallothionein transgene reversed L‐NAME‐induced changes in Bax, Bcl‐2, BAD phosphorylation, Caspase 9, Caspase 12 and cleaved Caspase 3. Our results suggest that metallothionein protects against L‐NAME‐induced myocardial contractile anomalies in part through inhibition of apoptosis. 相似文献
18.
Rationale
Biomass is the energy source for cooking and heating for billions of people worldwide. Despite their prevalent use and their potential impact on global health, the effects of these fuels on lung biology and function remain poorly understood.Methods
We exposed human small airway epithelial cells and C57BL/6 mice to dung biomass smoke or cigarette smoke to compare how these exposures impacted lung signaling and inflammatory and proteolytic responses that have been linked with disease pathogenesis.Results
The in vitro exposure and siRNA studies demonstrated that biomass and cigarette smoke activated ERK to up regulate IL-8 and MMP-1 expression in human airway epithelial cells. In contrast to cigarette smoke, biomass also activated p38 and JNK within these lung cells and lowered the expression of tissue inhibitor of matrix metalloproteinase-1 (TIMP-1). Similarly, in the lungs of mice, both biomass and cigarette smoke exposure increased macrophages, activated ERK and p38 and up regulated MMP-9 and MMP-12 expression. The main differences seen in the exposure studies was that mice exposed to biomass exhibited more perivascular inflammation and had higher G-CSF and GM-CSF lavage fluid levels than mice exposed identically to cigarette smoke.Conclusion
Biomass activates similar pathogenic processes seen in cigarette smoke exposure that are known to result in the disruption of lung structure. These findings provide biological evidence that public health interventions are needed to address the harm associated with the use of this fuel source. 相似文献19.
Objectives
Ample clinical and experimental evidence indicated that patients with Alzheimer''s disease display a high incidence of cardiovascular events. This study was designed to examine myocardial histology, cardiomyocyte shortening, intracellular Ca2+ homeostasis and regulatory proteins, electrocardiogram, adrenergic response, endoplasmic reticulum (ER) stress and protein carbonyl formation in C57 wild-type (WT) mice and an APPswe/PS1dE9 transgenic (APP/PS1) model for Alzheimer''s disease.Methods
Cardiomyocyte mechanical properties were evaluated including peak shortening (PS), time-to-PS (TPS), time-to-relengthening (TR), maximal velocity of shortening and relengthening (±dL/dt), intracellular Ca2+ transient rise and decay.Results
Little histological changes were observed in APP/PS1 myocardium. Cardiomyocytes from APP/PS1 but not APP or PS1 single mutation mice exhibited depressed PS, reduced±dL/dt, normal TPS and TR compared with WT mice. Rise in intracellular Ca2+ was lower accompanied by unchanged resting/peak intracellular Ca2+ levels and intracellular Ca2+ decay in APP/PS1 mice. Cardiomyocytes from APP/PS1 mice exhibited a steeper decline in PS at high frequencies. The responsiveness to adrenergic agonists was dampened although β1-adrenergic receptor expression was unchanged in APP/PS1 hearts. Expression of the Ca2+ regulatory protein phospholamban and protein carbonyl formation were downregulated and elevated, respectively, associated with unchanged SERCA2a, Na+-Ca2+ exchanger and ER stress markers in APP/PS1 hearts. Our further study revealed that antioxidant N-acetylcysteine attenuated the contractile dysfunction in APP/PS1 mice.Conclusions
Our results depicted overt cardiomyocyte mechanical dysfunction in the APP/PS1 Alzheimer''s disease model, possibly due to oxidative stress. 相似文献20.
Fernando M Botelho Jake K Nikota Carla MT Bauer Mathieu C Morissette Yoichiro Iwakura Roland Kolbeck Donna Finch Alison A Humbles Martin R St?mpfli 《Respiratory research》2012,13(1):81