Differential cell stress responses to food availability by the nestlings of Asian Short-toed Lark(Calandrella cheleensis)

Background:Timing of breeding season of temperate passerines has been considered to be adjusted to their food availability.There is little work to reveal the cell stress responses of the nestlings hatched asynchronized with the food abundance peak,which is important for understanding the physiological link between the timing of breeding and the fitness of offspring.Methods:Using gene expression level of blood HSP70 and HSP90 as indicators,we compared the cell stress response of Asian Short-toed Lark(Calandrella cheleensis)nestlings hatched under conditions of low,mid or high food(grasshopper nymph)availability in 2017.Results:Nymph biomass,sample time and interaction of these two factors significantly influenced the blood gene expression level of HSP70 and HSP90 of Asian Short-toed Lark nestlings.HSP70 and HSP90 gene expression levels of the nestlings at 14:00 were significantly higher than those at 5:00.At either 5:00 or 14:00,the gene expression levels of HSP70 and HSP90 increase with the decrease of nymph biomass.Conclusions:These results indicate that food availability is an important environment factor inducing cellular stress of Asian Short-toed Lark nestlings.The interactive effect of the nymph abundance and sample time on the HSPs response may be related with the daily temperature variation of the grassland.Over cell stress response may be one of physiological factor mediating the effect of food availability and the nestling’s fitness.

Monitoring the pH fluctuation of lysosome under cell stress using a near-infrared ratiometric fluorescent probe

Cell stress responses are associated with numerous diseases including diabetes, neurodegenerative diseases, and cancer. Several events occur under cell stress, in which, are protein expression and organellespecific pH fluctuation. To understand the lysosomal pH variation under cell stress, a novel NIR ratiometric pH-responsive fluorescent probe(BLT) with lysosomes localization capability was developed.The quinoline ring of BLT combined with hydrogen ion which triggered the rearrangement of π electrons conjugated at low pH medium, meanwhile, the absorption and fluorescent spectra of BLT showed a red-shifts, which gived a ratiometric signal. Moreover, the probe BLT with a suitable p Kavalue has the potential to discern changes in lysosomal pH, either induced by heat stress or oxidative stress or acetaminophen-induced(APAP) injury stress. Importantly, this ratiometric fluorescent probe innovatively tracks pH changes in lysosome in APAP-induced liver injury in live cells, mice, and zebrafish. The probe BLT as a novel fluorescent probe possesses important value for exploring lysosomal-associated physiological varieties of drug-induced hepatotoxicity.

Subversion of cellular stress responses by poxviruses

Cellular stress responses are powerful mechanisms that prevent and cope with the accumulation of macromolecular damage in the cells and also boost host defenses against pathogens. Cells can initiate either protective or destructive stress responses depending, to a large extent, on the nature and duration of the stressing stimulus as well as the cell type. The productive replication of a virus within a given cell places inordinate stress on the metabolism machinery of the host and, to assure the continuity of its replication, many viruses have developed ways to modulate the cell stress responses. Poxviruses are among the viruses that have evolved a large number of strategies to manipulate host stress responses in order to control cell fate and enhance their replicative success. Remarkably, nearly every step of the stress responses that is mounted during infection can be targeted by virally encoded functions. The fine-tuned interactions between poxviruses and the host stress responses has aided virologists to understand specific aspects of viral replication; has helped cell biologists to evaluate the role of stress signaling in the uninfected cell; and has tipped immunologists on how these signals contribute to alert the cells against pathogen invasionand boost subsequent immune responses. This review discusses the diverse strategies that poxviruses use to subvert host cell stress responses.

Effects of chronic heat stress on granulosa cell apoptosis and follicular atresia in mouse ovary

Background： Heat stress is known to alter follicular dynamics and granulosa cell function and may contribute to the diminished reproductive efficiency commonly observed in mammals during the summer. Although several investigators have studied heat-induced ovarian injury, few reports have focused on the effects of chronic heat stress on ovarian function and the molecular mechanisms through which it induces ovarian injury.Methods： In Exp. 1, 48 female mice were assigned to a control or heat-stressed treatment. After exposure to a constant temperature of 25 ℃ for 7, 14, 21 or 28 d（n = 6） or to 42 ℃ for 3 h per d for 7, 14, 21 or 28 d（n = 6）, the mice were euthanized and their ovaries were analyzed for follicular atresia, granulosa cell apoptosis, changes in the abundance of HSP70 protein and serum concentrations of estradiol. In Exp. 2, the expression of HSP70 and aromatase was quantified in antral follicles cultured in vitro at 37 or 42 ℃ for 24 h. In Exp. 3, granulosa cells from ovaries maintained at 37 or 41 ℃ for 2 h were analyzed for their expression of HSP70, Bim, caspase-3 and cleaved caspase-3.Results： In Exp. 1, body weight and food intake of heat-stressed mice decreased（P 〈 0.05） compared with control mice while the concentration of estradiol in serum was lower（P 〈 0.05） in heat-stressed mice than in control mice. Compared with control mice, the percentage of atretic follicles and the number of antral follicles with severe apoptotic signals were increased（P 〈 0.05） after 21 d of heat-stressed treatment. HSP70 protein was more abundant（P 〈 0.05） in heat-stressed mice than control mice. In Exp. 2, heat stress increased HSP70 and decreased aromatase proteins（P 〈 0.05） in antral follicles. In Exp. 3, TUNEL-positive granulosa cells from heat-stressed ovaries were observed concomitant with a significant increase in HSP70, Bim and cleaved caspase-3 protein.Conclusion： Heat-stress in mice decrease estradiol in serum and aromatase in antral follicles but increased number of atretic follicles and granulosa cell undergoing apoptosis which may explain the decreased fertility commonly observed in heat-stressed animals.

Simulation of thermal and sodium expansion stress in aluminum reduction cells

Two finite element(FE) models were built up for analysis of stress field in the lining of aluminum electrolysis cells.Distribution of sodium concentration in cathode carbon blocks was calculated by one FE model of a cathode block.Thermal stress field was calculated by the other slice model of the cell at the end of the heating-up.Then stresses coupling thermal and sodium expansion were considered after 30 d start-up.The results indicate that sodium penetrates to the bottom of the cathode block after 30 d start-up.The semi-graphitic carbon block has the largest stress at the thermal stage.After 30 d start-up the anthracitic carbon has the greatest sodium expansion stress and the graphitized carbon has the lowest sodium expansion stress.Sodium penetration can cause larger deformation and stress in the cathode carbon block than thermal expansion.

Simulation on Residual Stress of Shot Peening Based on a Symmetrical Cell Model

The symmetrical cell model is widely used to study the residual stress induced by shot peening. However, the correlation between the predicted residual stresses and the shot peening coverage, which is a big challenge for the researchers of the symmetrical cell model, is still not established. Based on the dynamic stresses and the residual stresses outputted from the symmetrical cell model, the residual stresses corresponding to full coverage are evalu- ated by normal distribution analysis. The predicted nodal dynamic stresses with respect to four corner points indicate that the equi-biaxial stress state exists only for the first shot impact. Along with the increase of shot number, the interactions of multiple shot impacts make the fluctuation of the nodal dynamic stresses about an almost identical value more and more obvious. The mean values and standard deviations of the residual stresses gradually tend to be stable with the increase of the number of shot peening series. The mean values at each corner point are almost the same after the third peening series, which means that an equi-biaxial stress state corresponding to the full coverage of shot peening is achieved. Therefore, the mean values of the nodal residual stresses with respect to a specific transverse cross-section below the peened surface can be used to correlate the measured data by X-ray. The predicted residual stress profile agrees with the experimental results very well under 200% peening coverage. An effective correlation method is proposed for the nodal residual stresses predicted by the symmetrical cell model and the shot peening coverage.

Imipramine protects retinal ganglion cells from oxidative stress through the tyrosine kinase receptor B signaling pathway

Retinal ganglion cell（RGC） degeneration is irreversible in glaucoma and tyrosine kinase receptor B（Trk B）-associated signaling pathways have been implicated in the process.In this study,we attempted to examine whether imipramine,a tricyclic antidepressant,may protect hydrogen peroxide（H_2O_2）-induced RGC degeneration through the activation of the Trk B pathway in RGC-5 cell lines.RGC-5 cell lines were pre-treated with imipramine 30 minutes before exposure to H_2O_2.Western blot assay showed that in H_2O_2-damaged RGC-5 cells,imipramine activated Trk B pathways through extracellular signal-regulated protein kinase/Trk B phosphorylation.TUNEL staining assay also demonstrated that imipramine ameliorated H_2O_2-induced apoptosis in RGC-5 cells.Finally,Trk B-Ig G intervention was able to reverse the protective effect of imipramine on H_2O_2-induced RGC-5 apoptosis.Imipramine therefore protects RGCs from oxidative stress-induced apoptosis through the Trk B signaling pathway.

Carbon Monoxide Inhibits the Nuclear-cytoplasmic Translocation of HMGB1 in an In Vitro Oxidative Stress Injury Model of Mouse Renal Tubular Epithelial Cells

Carbon monoxide（CO）,as a vital small molecule in signaling pathways,is found to be involved in ischemia-reperfusion injury（IRI） in renal transplantation.CO-releasing molecule-2（CORM-2）,a CO-releasing molecule,is a type of metal carbonyl complexes which can quickly release CO in vivo.In this study,an in vitro oxidative stress injury model was established to examine the effect of CORM-2 pretreatment on the nuclear-cytoplasmic translocation of high mobility group box 1 protein（HMGB1） in mouse primary renal proximal tubular epithelial cells（RPTECs）.Immunofluorescence staining showed that HMGB1 in the medium-and CORM-2-treated groups was predominantly localized in the nucleus of the cells,whereas higher amounts of HMGB1 translocated to the cytoplasm in the H2O2-and inactive CORM-2（i CORM-2）-treated groups.Western blotting of HMGB1 showed that the total amounts of cytoplasmic HMGB1 in the H2O2-treated（0.59±0.27） and i CORM-2-treated（0.57±0.22） groups were markedly higher than those in the medium-treated（0.19±0.05） and CORM-2-treated（0.21±0.10） groups（P〈0.05）.Co-immunoprecipitation showed that the levels of acetylated HMGB1 in the H2O2-treated（642.98±57.25） and i CORM-2-treated（342.11±131.25） groups were markedly increased as compared with the medium-treated（78.72±74.17） and CORM-2-treated（71.42±53.35） groups（P〈0.05）,and no significant difference was observed between the medium-treated and CORM-2-treated groups（P〉0.05）.In conclusion,our study demonstrated that in the in vitro oxidative stress injury model of primary RPTECs,CORM-2 can significantly inhibit the nuclear-cytoplasmic translocation of HMGB1,which is probably associated with the prevention of HMGB1 acetylation.

Liraglutide reduces oxidized LDL-induced oxidative stress and fatty degen- eration in Raw 264.7 cells involving the AMPK/SREBP1 pathway

BackgoundRecent 研究在动脉粥样硬化患者的预防和稳定为 liraglutide 建议了一个潜在的角色脉管的疾病。然而，在动脉粥样硬化上位于 liraglutide 的效果下面的分子的机制很好没被阐明。这研究的目的是检验 liraglutide 是否经由 AMP-activated&#x000a0 的调整免于氧化应力和丰满的退化； protein&#x000a0 ； kinase ( AMPK ) /sterol 规章的元素绑定抄写因素 1 ( SREBP1 )在泡沫 cells.MethodsMouse 巨噬细胞 Raw264.7 房间表明小径暴露于氧化低密度脂蛋白( oxLDL )导致泡沫房间的形成。房间与 oxLDL 被孵化(50 &#x000b5； g/mL ) ， liraglutide (0.1， 0.5， 1 和 2 nmol/L ) 或 exendin-3 (9-39 )(1， 10 和 100 nmol/L ) 独自，或在里面联合。染色的油红 O 被用来检测细胞内部的类脂化合物微滴。TG 和胆固醇的层次用商业工具包被测量。氧化应力被测量细胞内部的反应的氧种类(ROS ) 决定， malondialdehyde (MDA ) 和 superoxide dismutase 1 (草皮) 。西方的污点分析被用来检验 AMPK&#x003b1 的表示； 1 ， SREBP1 ， phosphorylated AMPK&#x003b1 ； 1 ， phosphorylated SREBP1 ，象glucagon一样 peptide-1 ( GLP-1 )和 GLP-1 染色的受体( GLP-1R ) .ResultsOil 红 O 证明细胞质的类脂化合物微滴累积被处理显然与 liraglutide 在泡沫房间减少。在对待 liraglutide 的泡沫房间的 TG 和胆固醇内容显著地被减少。另外，泡沫房间表明了一个损害氧化压力追随者 liraglutide 处理，证实了由增加的草皮，和减少的 ROS 和 MDA。然而，泡沫房间上的 liraglutide 的这些效果被 GLP-1R 对手 exendin-3 (9-39 ) 的使用稀释。而且，我们发现表示 AMPK&#x003b1 铺平； 1 并且 phosphorylated AMPK&#x003b1 ；当 SREBP1 和 phosphorylated SREBP1 的表示水平显著地在与第一次表明的 liraglutide.ConclusionsThis 学习跟随处理的泡沫房间被减少时， 1 显著地被增加减少氧化应力和丰满的退化在里面上的 liraglutide 的效果 导致oxLDL 的 Raw264.7 房间被 AMPK/SREBP1 小径的改变伴随。这研究在减少氧化应力和丰满的退化上为 liraglutide 的效果提供了潜在的分子的机制。

Involvement of Endoplasmic Reticulum Stress in Apoptosis of Testicular Cells Induced by Low-dose Radiation

Summary： The study examined the role of endoplasmic reticulum stress （ERS） and signaling pathways of inositol-requiring enzyme-1 （IRE1）, RNA-activated protein kinase-like ER kinase （PERK） and activating transcription factor-6 （ATF6） in apoptosis of mouse testicular cells treated with low-dose radiation （LDR）. In the dose-dependent experiment, the mice were treated with whole-body X-ray irradiation at different doses （25, 50, 75, 100 or 200 mGy） and sacrificed 12 h later. In the time-dependent experiment, the mice were exposed to 75 mGy X-ray irradiation and killed at different time points （3, 6, 12, 18 or 24 h）. Testicular cells were harvested for experiments. H202 and NO concentrations, and Ca2＋-ATPase activity were detected by biochemical assays, the calcium ion concentration （[Ca2＋]i） by flow cytometry using fluo-3 probe, and GRP78 mRNA and protein expressions by quantitative real-time RT-PCR （qRT-PCR） and Western blotting, respectively. The mRNA expressions of S-XBP1, JNK, caspase-12 and CHOP were measured by qRT-PCR, and the protein expressions of IREla, S-XBP1, p-PERK, p-elF2a, ATF6 p50, p-JNK, pro-caspase-12, cleaved caspase-12 and CHOP by Western blot- ting. The results showed that the concentrations of H202 and NO, the mR_NA expressions of GRP78, S-XBP1, JNK, caspase-12 and CHOP, and the protein expressions of GRP78, S-XBP1, IREla, p-PERK, p-elF2a, ATF6 p50, p-JNK, pro-caspase-12, cleaved caspase-12 and CHOP were significantly increased in a time- and dose-dependent manner after LDR. But the [Ca2]i and Ca2-ATPase activities were sig nificantly decreased in a time and dose-dependent manner. It was concluded that the ERS, regulated by IRE 1, PERK and ATF6 pathways, is involved in the apoptosis of testicular cells in LDR mice, which is associated with ERS-apoptotic signaling molecules of JNK, caspase-12 and CHOP.

Involvement of the Mitochondrion-dependent and the Endoplasmic Reticulum Stress-signaling Pathways in Isoliquiritigenin-induced Apoptosis of HeLa Cell

Objective Isoliquiritigenin （ISL）, a licorice chalconoid, is considered to be a bioactive agent with chemopreventive potential. This study investigates the mechanisms involved in ISL-induced apoptosis in human cervical carcinoma HeLa cells. Methods Cell viability was evaluated using a 3-（4, 5-dimethylthiazol-2-yl）-2, 5-diphenyl-tetrazolium bromide （MTT） assay. Apoptosis was determined by flow cytometry using an Annexin V-FITC Apoptosis Detection Kit. The intracetlular ROS levels were assessed using a 2, 7-dichlorofluorescein probe assay. The mitochondrial membrane potential was measured with the dual-emission potential-sensitive probe 5, 5＇, 6, 6＇-tetra-chloro-1, 1＇, 3, 3＇-tetraethyl-imidacarbocyanine iodide （JC-1）. The degradation of poly-ADP-ribose polymerase （PARP） protein, the phosphorylation of PKR-like ER kinase （PERK）, the phosphorylation of the a-subunit of eukaryotic initiation factor 2 （elF2a）, the expression of the 78 kD glucose-regulated protein （GRP 78）, and the activation of caspase-12 were analyzed via western blot analysis. Results ISL significantly inhibited the proliferation, the increase in ROS levels and apoptotic rates of HeLa cells in a concentration-dependent manner. Moreover, ISL induced mitochondrial dysfunction, caspase activation, and PARP cleavage, which displayed features of mitochondria dependent on apoptotic signals. Besides, exposure of HeLa cells to ISL triggered endoplasmic reticulum （ER） stress, as indicated by the increase in p-elF2a and GRP78 expression, ER stress-dependent apoptosis is caused by the activation of ER-specific caspase-12. Conclusion The findings from our study suggest that ISL-induced oxidative stress causes HeLa cel apoptosis via the mitochondrion-dependent and the ER stress-triggered signaling pathways.

Mucosal mast cells are pivotal elements in inflammatory bowel disease that connect the dots:Stress,intestinal hyperpermeability and inflammation

Mast cells (MC) are pivotal elements in several physiological and immunological functions of the gastro- intestinal (GI) tract. MC translate the stress signals that has been transmitted through brain gut axis into release of proinflammatory mediators that can cause stimulation of nerve endings that could affect afferent nerve terminals and change their perception, affect intestinal motility, increase intestinal hyperpermeability and, in susceptible individuals, modulate the inflammation. Thus, it is not surprising that MC are an important element in the pathogenesis of inflammatory bowel disease and non inflammatory GI disorders such as IBS and mast cell enterocolitis.

Copper Ions Stimulate the Proliferation of Hepatic Stellate Cells via Oxygen Stress in vitro

This study examined the effect of copper ions on the proliferation of hepatic stellate cells （HSCs） and the role of oxidative stress in this process in order to gain insight into the mechanism of he- patic fibrosis in Wilson＇s disease. LX-2 cells, a cell line of human HSCs, were cultured in vitro and treated with different agents including copper sulfate, N-acetyl cysteine （NAC） and buthionine sulfoxi- mine （BSO） for different time. The proliferation of LX-2 cells was measured by non-radioactive cell proliferation assay. Real-time PCR and Westem blotting were used to detect the mRNA and protein ex- pression of platelet-derived growth factor receptor 13 subunit （PDGFI3R）, ELISA to determine the level of glutathione （GSH） and oxidized glutathione （GSSG）, dichlorofluorescein assay to measure the level of reactive oxygen species （ROS）, and lipid hydroperoxide assay to quantify the level of lipid peroxide （LPO）. The results showed that copper sulfate over a certain concentration range could promote the pro- liferation of LX-2 cells in a time- and dose-dependent manner. The effect was most manifest when LX-2 cells were treated with copper sulfate at a concentration of 100 ~tmol/L for 24 h. Additionally, copper sulfate could dose-dependently increase the levels of ROS and LPO, and decrease the ratio of GSH/GSSG in LX-2 cells. The copper-induced increase in mRNA and protein expression of PDGF^R was significantly inhibited in LX-2 cells pre-treated with NAC, a precursor of GSH, and this phenome- non could be reversed by the intervention of BSO, an inhibitor of NAC. It was concluded that copper ions may directly stimulate the proliferation of HSCs via oxidative stress. Anti-oxidative stress therapies may help suppress the copper-induced activation and proliferation of HSCs.

Stress urinary incontinence in women and cell therapy: What can we expect from the future?

Stress urinary incontinence(SUI)is a common disorder that affects a large number of women and their quality of life.The aim of SUI therapy is to restore the existing urethral function via physical therapy,biofeedback,pelvic floor rehabilitation,pharmacological therapy,bulking agents and surgical approaches.Currently,the gold standard for the management of SUI is the tensionfree vaginal sling,which provides structural support to the female urethra.However,even minimally invasive surgical procedure such as"slings"carries risks for the patients,lost efficacy over the time and has long-term complications.For this reason,new therapeutic modalities are needed.Cell therapy has been emerged as an alternative to be used on the treatment of different diseases.The use of stem cells as a therapeutic option for SUI is an attractive alternative because,theoretically,injected cells could restore functional muscle cells and aid in sphincter closure in women with sphincterassociated incontinence.This study aims to review the current literature regarding evidences for using stem cell therapy on stress urinary incontinence in women.

Cis-hydroxyproline-induced inhibition of pancreatic cancer cell growth is mediated by endoplasmic reticulum stress

瞄准：在老鼠上调查 cis-hydroxyproline (CHP ) 的生物效果，并且检验内在的分子的机制胰腺的癌房间线 DSL6A。方法：DSL6A 房间增长上的 CHP 的效果被使用 BrdU 加入估计。焦点的粘附激酶(FAK ) 的表示被西方的弄污和免疫荧光描绘。endoplasmic 感应(嗯) 应力被使用 RT-PCR 并且为葡萄糖相关的 protein-78 (GRP78 ) 和生长拘捕和 DNA 的西方的弄污调查可诱导的基因(GADD153 ) 。房间生存能力通过基于 DSL6A 房间的减小潜力测量新陈代谢的活动被决定。Apoptosis 被 caspase-3 激活的察觉和多形核白细胞(自动数据处理核糖) 的劈开分析象 DNA laddering 一样的聚合酶(PARP ) 。结果：除了增长的抑制，有 CHP 的孵化从焦点的粘附导致了 FAK 的解朊的劈开和酶的 delocalisation，由房间坚持的损失列在后面。同时，我们能显示出 GRP78 和 GADD153 的增加的表情，显示在 DSL6A 房间线的 ER 压力串联的调停 CHP 的激活。有 CHP 的 DSL6A 房间的延长孵化最后导致了 apoptotic 细胞死亡。在 L 脯氨酸旁边，由一个广谱朊酶禁止者的增加的细胞内部的解朊作用的抑制能在细胞的功能和分子的过程上废除 CHP 的效果。相反，阻碍执行 apoptosis caspases 的活动没在调停 CHP 的房间损坏上有影响。结论：我们的数据建议开始嗯由 CHP 的压力机械导致细胞内部的解朊的进程的激活包括 caspase 独立的 FAK 降级，导致损坏胰腺的癌房间。

Morphological and migratory alterations in retinal Müller cells during early stages of hypoxia and oxidative stress

In the present study, retinal MOiler cells were cultured in vitro and treated with hydrogen peroxide （oxidative stressor） and cobalt chloride （hypoxic injury）. Following 24 hours of culture, compensatory hypertrophy was observed and cellular apoptosis increased. Hypoxia enhanced the migration ability of retinal MOiler cells and induced the expression of a-smooth muscle actin. Oxidative stress altered the morphology of MOiler cells when compared with hypoxia treatment.

Effects of Layer Thickness on the Residual Stresses of CIGS Solar Cells with Polyimide Substrate

In this paper, we investigate the effect of layer thickness on the residual stresses of copper indium gallium diselenide (CIGS) solar cells with polyimide substrate caused by CIGS layer deposition at 400?C and then cooling down to room temperature using the Finite Element Method (FEM). Moreover, we also examined the effect of layer thickness on residual stress of CIGS solar cells after cooling down to room temperature from the hotspot temperatures of 200?C, 300?C, and 400?C. Our simulated CIGS is composed of five layers: ZnO, CdS, CIGS, Mo, and PI substrate. We were able to quantify the effect of each layer’s thickness and hotspot temperature on the average stresses of each layer for the CIGS solar cells. We found that the PI substrate layer has the most significant effect on the residual stress of CIGS solar cells. Our simulation results reveal that the stress type (tensile vs. compressive) and the magnitude of stress of the CIGS layer (main absorber layer) can be controlled by changing the thickness of the PI substrate while applying a heat to CIGS solar cells. Quantitative analysis of relationship between layer thickness and thermo-mechanical stress of thin film solar cells can help solar cell manufacturers design more robust and reliable solar cells. For example, fabricating PI layer thickness less than 17 μm can improve the performance of CIGS solar cells by nullifying the compressive residual stress in the CIGS absorber layer.

Endoplasmic reticulum stress-induced apoptosis in intestinal epithelial cells:a feed-back regulation by mechanistic target of rapamycin complex 1(mTORC1)

Background: Endoplasmic reticulum(ER) stress is associated with multiple pathological processes of intestinal diseases. Despite a critical role of mechanistic target of rapamycin complex 1(m TORC1) in regulating cellular stress response, the crosstalk between m TORC1 and ER stress signaling and its contribution to the intestinal barrier function is unknown.Results: In the present study, we showed that intestinal epithelial cells(IEC-6) incubated with tunicamycin led to caspase-3-dependent apoptotic cell death. The induction of cell death was accompanied by activation of unfolded protein response as evidenced by increased protein levels for Bi P, p-IRE1α, p-e IF2α, p-JNK, and CHOP. Further study demonstrated that tunicamycin-induced cell death was enhanced by rapamycin, a specific inhibitor of m TORC1.Consistently, tunicamycin decreased transepithelial electrical resistance(TEER) and increased permeability of the cells. These effects of tunicamycin were exacerbated by m TORC1 inhibitor.Conclusions: Taken together, the data presented here identified a previously unknown crosstalk between an unfold protein response and m TORC1 signaling in the intestinal epithelium. This feed-back loop regulation on ER stress signaling by m TORC1 is critical for cell survival and intestinal permeability in epithelial cells.

Rifampicin inhibits apoptosis in rotenone-induced differentiated PC12 cells by ameliorating mitochondrial oxidative stress

BACKGROUND： Previous studies have shown that rifampicin exhibits neuroprotective effects, but the precise mechanisms remain unclear. Rifampicin is thought to exert the neuroprotective effect as a hydroxyl free radical scavenger. OBJECTIVE： To investigate the protective effects of rifampicin pretreatment on rotenone-induced mitochondrial oxidative stress in differentiated PC12 cells.DESIGN, TIME AND SETrlNG： A repeated measure, cell-based study was performed at the Department of Neurology, Second Affiliated Hospital, Sun Yat-sen University, China between December 2007 and November 2008. MATERIALS： PC12 cells were a kind gift from the Physiology Laboratory of Zhongshan Medical School, Sun Yat-sen University, China. Rotenone and rifampicin were purchased from Sigma, USA. METHODS： PC12 cells were differentiated by culturing with 100 ng/mL 7S nerve growth factor for 9 days in Dulbecco＇s modified Eagle＇s medium/Nutrient Mix F12 （DMEM/F12） supplemented with 10% fetal bovine serum. The cells were assigned to six groups according to various treatment conditions： control, cultured with normal media; rifampicin group, treated with 300 pmol/L rotenone for 26 hours; rotenone group, treated with 2.5 pmol/L rotenone for 24 hours; rifampicin pretreatment groups, pretreated with 100, 200, and 300 pmol/L rifampicin for 2 hours, respectively, followed by 2.5 μmol/L rotenone for 24 hours.MAIN OUTCOME MEASURES： Mitochondrial membrane potential was measured by fluorescence microscopy and flow cytometry, respectively, using rhodamine123 staining. Intracellular reactive oxygen species formation was analyzed by flow cytometry using 2＇, 7＇-dichlorofluorescin-diacetate staining, and intracellular reduced glutathione was measured with a microplate reader. Cell viability was determined by 3-（4, 5-dimethylthiazol-2-yl）-2, 5-diphenyltetrazolium bromide assay. Cell apoptosis was detected by Hoechst 33342 staining and flow cytometry. RESULTS： Increased apoptosis in rotenone-induced, differentiated, PC12 cells was accompanied by the loss of mitochondrial transmembrane potential, the formation of reactive oxygen species, and reduced glutathione depletion （P 〈 0.01）. Rotenone-induced mitochondrial dysfunction was blocked in a dose-dependent manner by rifampicin （P 〈 0.05 or P 〈 0.01）, CONCLUSION： Pretreatment of differentiated PC12 cells with rifampicin blocked rotenone-induced apoptosis by ameliorating mitochondrial dysfunction and oxidative stress.

Research on stress-induced apoptosis of natural killer cells and the alteration of their killing activity in mouse liver

AIM:To investigate the stress-induced apoptosis of natural killer(NK)cells and the changes in their killing activity in mouse livers.METHODS:A restraint stress model was established in mice.Flow cytometry was employed to measure the percentage of NK cells and the changes in their absolute number in mouse liver.The cytotoxicity of hepatic and splenic NK cells was assessed against YAC-1 target cells via a 4 h 51Cr-release assay.RESULTS:The restraint stress stimulation induced the apoptosis of NK cells in the liver and the spleen,which decreased the cell number.The number and percentage of NK cells in the spleen decreased.However,the number of NK cells in the liver decreased,whereas the percentage of NK cells was significantly increased.The apoptosis of NK cells increased gradually with prolonged stress time,and the macrophage-1(Mac-1)+NK cells were more susceptible to apoptosis than Mac-1-NK cells.Large numbers of Mac-1-NK cells in the liver,which are more resistant to stress-induced apoptosis,were observed than the Mac-1-NK cells in the spleen.The stress stimulation diminished the killing activity of NK cells in the spleen was significantly decreased,but the retention of numerous Mac-1-NK cells in the liver maintained the killing ability.CONCLUSION:Significant stress-induced apoptosis was observed among Mac-1+NK cells,but not Mac-1-NK cells in the mouse liver.Stress stimulation markedly decreased the killing activity of NK cells in the spleen but remained unchanged in the liver.