Summary: The pathogenesis of hyperoxia lung injury and the mechanism of amygdalin on type 2 alveolar epithelial cells (AEC2) isolated from premature rat lungs in vitro were investigated. AEC2 were obtained by primary ...Summary: The pathogenesis of hyperoxia lung injury and the mechanism of amygdalin on type 2 alveolar epithelial cells (AEC2) isolated from premature rat lungs in vitro were investigated. AEC2 were obtained by primary culture from 20-days fetal rat lung and hyperoxia-exposed cell model was established. Cell proliferating viability was examined by MTT assay after treatment of amygdalin at various concentrations. DNA content and the proliferating cell nuclear antigen (PCNA) protein expression of AEC2 were measured by using flow cytometry and immunocytochemistry respectively after 24 h of hyperoxia exposure or amygdalin treatment. The results showed that hyperoxia inhibited the proliferation and decreased PCNA protein expression in AEC2 of premature rat in vitro. Amygdalin at the concentration range of 50-200 μmol/L stimulated the proliferation of AEC2 in a dose-dependent manner, however, 400 μmol/L amygdalin inhibited the proliferation of AEC2. Amygdalin at the concentration of 200 μmol/L played its best role in facilitating proliferation of AEC2s in vitro and could partially ameliorated the changes of proliferation in hyperoxia exposed AEC2 of premature rat. It has been suggested that hyperoxia inhibited the proliferation of AEC2s of premature rat, which may contribute to hyperoxia lung injury. Amygdalin may play partial protective role in hyperoxia-induced lung injury.展开更多
To establish a better method of primary culture for alveolar epithelial type Ⅱ cells （AEC Ⅱ ） and to study its bionomics, alveolar epithelial type Ⅱ cells were isolated by digestion with trypsin and collagenase, ...To establish a better method of primary culture for alveolar epithelial type Ⅱ cells （AEC Ⅱ ） and to study its bionomics, alveolar epithelial type Ⅱ cells were isolated by digestion with trypsin and collagenase, which were then purified by plated into culture flask coated with rat immunoglobulin （i The purified AEC Ⅱ were identified by alkaline phosphatase staining, electron mi- croscopy, immunocytochemical staining of pulmonary surfactant protein A （SPA）. The SPA expression and transfection characteristics were compared with those of A549 cell line. The results showed that AEC Ⅱ could be isolated by digestion with trysin and collagenase and purified by adhesive purification by using IgG, with a yield of about 2-3 × 10^7, and a purity of about 75%-84 %. Cells could be quickly identified with AKP staining. AEC Ⅱ were different from A549 cell line in terms of SPA expression and transfection characteristics. It is concluded that adhesive purification with IgG can improve the purity of AEC Ⅱ, and AKP staining is simple in cell identification. AEC Ⅱ can not be completely replaced by A549 cells in some studies because the differences between them, such as SPA expression.展开更多
Objective:To investigate the effects of mechanical stretching and lipopolysaccharide(LPS) on the early apoptosis and IL-8 production of alveolar epithelial type II cells A549.Methods:The experimental matrix consisted ...Objective:To investigate the effects of mechanical stretching and lipopolysaccharide(LPS) on the early apoptosis and IL-8 production of alveolar epithelial type II cells A549.Methods:The experimental matrix consisted of three integrated studies.In the first study,A549 cells were subjected to different stretching strain frequency and duration time to see the effects on the early apoptosis.In the second study,A549 cells were subjected to mechanical stretch(13%4 h, 0.3 Hz) and LPS(1 or 100 ng/mL) to see whether mechanical strain and LPS also have an addictive effect on the early apoptosis.In the third study to investigate whether this addictive effect could be induced by LPS and mechanical stretch on IL-8 production,A549 cells were subjected to LPS(100 ng/mL) and mechanical strain(13%.0.3 Hz,4 h).Real time PCR and enzyme linked immunosorbent assay were used to measure mRN A and protein level of IL-8.The early apoptosis was detected by flow cytometry.Results:Mechanical stretch induced the early apoptosis in a force and frequency and time-dependent manner.In the presence of LPS,mechanical stretch enhanced LPS-induced early apoptosis,especially in 100 ng/mL IPS group compared with 1 ng/ mL LPS and the control group.Mechanical stretch increased IL-8 production and enhanced LPS-induced IL-8 screation both in mRNA and protein levels.Conclusions:Mechanical stretch can induce the early apoptosis and IL-8 secretion.Mechanical stretch and LPS have an addictive effect on the early apoptosis and IL-8 production in alveolar type 2 cells,which is one of the mechanisms of ventilator-induced lung injury.展开更多
This study investigated the effects of hyperoxia on dynamic changes of thioredoxin-1 （Trx1） and thioredoxin reductase-1 （TrxR1） in alveolar type Ⅱ epithelial cells （AECⅡ） of premature rats. Pregnant Sprague-Da...This study investigated the effects of hyperoxia on dynamic changes of thioredoxin-1 （Trx1） and thioredoxin reductase-1 （TrxR1） in alveolar type Ⅱ epithelial cells （AECⅡ） of premature rats. Pregnant Sprague-Dawley rats were sacrificed on day 19 of gestation. AECⅡ were isolated and purified from the lungs of premature rats. When cultured to 80% confluence, in vitro cells were randomly divided into air group and hyperoxia group. Cells in the hyperoxia group were continuously exposed to 95% O2/5% CO2 and those in the air group to 95% air/5% CO2. After 12, 24 and 48 h, cells in the two groups were harvested to detect their reactive oxygen species （ROS）, apoptosis, TrxR1 activity and the expressions of Trx1 and TrxR1 by corresponding protocols, respectively. The results showed that AECⅡ exposed to hyperoxia generated excessive ROS and the apoptosis percentage in the hyperoxia group was increased significantly at each time points as compared with that in the air group （P0.001）. Moreover, TrxR1 activity was found to be markedly depressed in the hyperoxia group in comparison to that in the air group （P0.001）. RT-PCR showed the expressions of both Trx1 and TrxR1 mRNA were significantly increased in AECⅡ exposed to hyperoxia for 12 and 24 h （P0.01）, respectively. At 48 h, the level of Trx1 mRNA as well as that of TrxR1 mRNA in the hyperoxia group was reduced and showed no significant difference from that in the air group （P0.05）. Western blotting showed the changes of Trx1 protein expressions in the hyperoxia group paralleled those of Trx1 mRNA expressions revealed by RT-PCR. It was concluded that hyperoxia can up-regulate the protective Trx1/TrxR1 expressed by AECⅡ in a certain period, however, also cause dysfunction of the cytoplasmic thioredoxin system by decreasing TrxR1 activity, which may contribute to the progression of oxidative stress and cell apoptosis and finally result in lung injury.展开更多
The role of the hypoxia-inducible factor(HIF)subunits 1α and 2α in response to hypoxia is well established in lungepithelial cells,whereas little is known about HIF-3α with respect to transcriptional and translatio...The role of the hypoxia-inducible factor(HIF)subunits 1α and 2α in response to hypoxia is well established in lungepithelial cells,whereas little is known about HIF-3α with respect to transcriptional and translational regulation by hy-poxia.HIF-3α and HIF-1α are two similar but distinct basic helix-loop-helix-PAS proteins,which have been postulatedto activate hypoxia responsive genes in response to hypoxia.Here,we used quantitative real time RT-PCR and immu-noblotting to determine the activation of HIF-3α vs.HIF-1α by hypoxia.HIF-3α was strongly induced by hypoxia(1%O_2)both at the level of protein and mRNA due to an increase in protein stability and transcriptional activation,whereasHIF-1α protein and mRNA levels enhanced transiently and then decreased because of a reduction in its mRNA stabilityin A549 cells,as measured on mRNA and protein levels.Interestingly,HIF-3α and HIF-1α exhibited strikingly similarresponses to a variety of activating or inhibitory pharmacological agents.These results demonstrate that HIF-3α is ex-pressed abundantly in lung epithelial cells,and that the transcriptional induction of HIF-3α plays an important role in theresponse to hypoxia in vitro.Our findings suggest that HIF-3α,as a member of the HIF system,is complementary ratherthan redundant to HIF-1α induction in protection against hypoxic damage in alveolar epithelial cells.展开更多
Alveolar epithelial cells(AECs)injury and failed reconstitution of the AECs barrier are both integral to alveolar flooding and subsequent pulmonary fibrosis(PF).Nevertheless,the exact mechanisms regulating the regener...Alveolar epithelial cells(AECs)injury and failed reconstitution of the AECs barrier are both integral to alveolar flooding and subsequent pulmonary fibrosis(PF).Nevertheless,the exact mechanisms regulating the regeneration of AECs post-injury still remain unclear.SMARCA4 is a part of the large ATP-dependent chromatin remodelling complex SWI/SNF,which is essential for kidney and heart fibrosis.We investigates SMARCA4 function in lung fibrosis by establishing PF mice model with bleomycin firstly and found that the expression of SMARCA4 was mainly enhanced in alveolar type II(ATII)cells.Moreover,we established an alveolar epithelium-specific SMARCA4-deleted SP-C-rtTA/(tetO)7-Cre/SMARCA4f/f mice(SOSM4D/D)model,as well as a new SMARCA4-deleted alveolar type II(ATII)-like mle-12 cell line.We found that the bleomycin-induced PF was more aggressive in SOSM4D/D mice.Also,the proliferation of ATII cells was decreased with the loss of SMARCA4 in vivo and in vitro.In addition,we observed increased proliferation of ATII cells accompanied by abnormally high expression of SMARCA4 in human PF lung sections.These data uncovered the indispensable role of SMARCA4 in the proliferation of ATII cells,which might affect the progression of PF.展开更多
Purpose:The incidence of acute lung injury(ALI)in severe trauma patients is 48%and the mortality rate following acute respiratory distress syndrome evolved from ALI is up to 68.5%.Alveolar epithelial type 1 cells(AEC1...Purpose:The incidence of acute lung injury(ALI)in severe trauma patients is 48%and the mortality rate following acute respiratory distress syndrome evolved from ALI is up to 68.5%.Alveolar epithelial type 1 cells(AEC1 s)and type 2 cells(AEC2s)are the key cells in the repair of injured lungs as well as fetal lung development.Therefore,the purification and culture of AECls and AEC2s play an important role in the research of repair and regeneration of lung tissue.Methods:Sprague-Dawley rats(3-4 weeks,120-150 g)were purchased for experiment.Dispase and DNase I were jointly used to digest lung tissue to obtain a single-cell suspension of whole lung cells,and then magnetic bead cell sorting was performed to isolate Tla positive cells as AECls from the single-cell suspension by using polyclonal rabbit anti-Tla(a specific AECls membrane protein)antibodies combined with anti-rabbit IgG microbeads.Afterwards,alveolar epithelial cell membrane marker protein EpCAM was designed as a key label to sort AEC2s from the remaining Tla-neg cells by another positive immunomagnetic selection using monoclonal mouse anti-EpCAM antibodies and anti-mouse IgG microbeads.Cell purity was identified by immunofluorescence staining and flow cytometry.Resii沾••The purity of AECls and AEC2s was 88.3%±3.8%and 92.6%±2.7%,respectively.The cell growth was observed as follows:AECls stretched within the 12-16 h,but the cells proliferated slowly;while AEC2s began to stretch after 24 h and proliferated rapidly from the 2nd day and began to differentiate after 3 days.Conclusion:AECls and AEC2s sorted by this method have high purity and good viability.Therefore,our method provides a new approach for the isolation and culture of AECls and AEC2s as well as a new strategy for the research of lung repair and regeneration.展开更多
文摘Summary: The pathogenesis of hyperoxia lung injury and the mechanism of amygdalin on type 2 alveolar epithelial cells (AEC2) isolated from premature rat lungs in vitro were investigated. AEC2 were obtained by primary culture from 20-days fetal rat lung and hyperoxia-exposed cell model was established. Cell proliferating viability was examined by MTT assay after treatment of amygdalin at various concentrations. DNA content and the proliferating cell nuclear antigen (PCNA) protein expression of AEC2 were measured by using flow cytometry and immunocytochemistry respectively after 24 h of hyperoxia exposure or amygdalin treatment. The results showed that hyperoxia inhibited the proliferation and decreased PCNA protein expression in AEC2 of premature rat in vitro. Amygdalin at the concentration range of 50-200 μmol/L stimulated the proliferation of AEC2 in a dose-dependent manner, however, 400 μmol/L amygdalin inhibited the proliferation of AEC2. Amygdalin at the concentration of 200 μmol/L played its best role in facilitating proliferation of AEC2s in vitro and could partially ameliorated the changes of proliferation in hyperoxia exposed AEC2 of premature rat. It has been suggested that hyperoxia inhibited the proliferation of AEC2s of premature rat, which may contribute to hyperoxia lung injury. Amygdalin may play partial protective role in hyperoxia-induced lung injury.
基金the National Natural Sciences Foundation of China (No. 30500224 and No. 30400193).
文摘To establish a better method of primary culture for alveolar epithelial type Ⅱ cells （AEC Ⅱ ） and to study its bionomics, alveolar epithelial type Ⅱ cells were isolated by digestion with trypsin and collagenase, which were then purified by plated into culture flask coated with rat immunoglobulin （i The purified AEC Ⅱ were identified by alkaline phosphatase staining, electron mi- croscopy, immunocytochemical staining of pulmonary surfactant protein A （SPA）. The SPA expression and transfection characteristics were compared with those of A549 cell line. The results showed that AEC Ⅱ could be isolated by digestion with trysin and collagenase and purified by adhesive purification by using IgG, with a yield of about 2-3 × 10^7, and a purity of about 75%-84 %. Cells could be quickly identified with AKP staining. AEC Ⅱ were different from A549 cell line in terms of SPA expression and transfection characteristics. It is concluded that adhesive purification with IgG can improve the purity of AEC Ⅱ, and AKP staining is simple in cell identification. AEC Ⅱ can not be completely replaced by A549 cells in some studies because the differences between them, such as SPA expression.
文摘Objective:To investigate the effects of mechanical stretching and lipopolysaccharide(LPS) on the early apoptosis and IL-8 production of alveolar epithelial type II cells A549.Methods:The experimental matrix consisted of three integrated studies.In the first study,A549 cells were subjected to different stretching strain frequency and duration time to see the effects on the early apoptosis.In the second study,A549 cells were subjected to mechanical stretch(13%4 h, 0.3 Hz) and LPS(1 or 100 ng/mL) to see whether mechanical strain and LPS also have an addictive effect on the early apoptosis.In the third study to investigate whether this addictive effect could be induced by LPS and mechanical stretch on IL-8 production,A549 cells were subjected to LPS(100 ng/mL) and mechanical strain(13%.0.3 Hz,4 h).Real time PCR and enzyme linked immunosorbent assay were used to measure mRN A and protein level of IL-8.The early apoptosis was detected by flow cytometry.Results:Mechanical stretch induced the early apoptosis in a force and frequency and time-dependent manner.In the presence of LPS,mechanical stretch enhanced LPS-induced early apoptosis,especially in 100 ng/mL IPS group compared with 1 ng/ mL LPS and the control group.Mechanical stretch increased IL-8 production and enhanced LPS-induced IL-8 screation both in mRNA and protein levels.Conclusions:Mechanical stretch can induce the early apoptosis and IL-8 secretion.Mechanical stretch and LPS have an addictive effect on the early apoptosis and IL-8 production in alveolar type 2 cells,which is one of the mechanisms of ventilator-induced lung injury.
基金supported by a grant from the National Natural Sciences Foundation of China (No. 30770944)
文摘This study investigated the effects of hyperoxia on dynamic changes of thioredoxin-1 （Trx1） and thioredoxin reductase-1 （TrxR1） in alveolar type Ⅱ epithelial cells （AECⅡ） of premature rats. Pregnant Sprague-Dawley rats were sacrificed on day 19 of gestation. AECⅡ were isolated and purified from the lungs of premature rats. When cultured to 80% confluence, in vitro cells were randomly divided into air group and hyperoxia group. Cells in the hyperoxia group were continuously exposed to 95% O2/5% CO2 and those in the air group to 95% air/5% CO2. After 12, 24 and 48 h, cells in the two groups were harvested to detect their reactive oxygen species （ROS）, apoptosis, TrxR1 activity and the expressions of Trx1 and TrxR1 by corresponding protocols, respectively. The results showed that AECⅡ exposed to hyperoxia generated excessive ROS and the apoptosis percentage in the hyperoxia group was increased significantly at each time points as compared with that in the air group （P0.001）. Moreover, TrxR1 activity was found to be markedly depressed in the hyperoxia group in comparison to that in the air group （P0.001）. RT-PCR showed the expressions of both Trx1 and TrxR1 mRNA were significantly increased in AECⅡ exposed to hyperoxia for 12 and 24 h （P0.01）, respectively. At 48 h, the level of Trx1 mRNA as well as that of TrxR1 mRNA in the hyperoxia group was reduced and showed no significant difference from that in the air group （P0.05）. Western blotting showed the changes of Trx1 protein expressions in the hyperoxia group paralleled those of Trx1 mRNA expressions revealed by RT-PCR. It was concluded that hyperoxia can up-regulate the protective Trx1/TrxR1 expressed by AECⅡ in a certain period, however, also cause dysfunction of the cytoplasmic thioredoxin system by decreasing TrxR1 activity, which may contribute to the progression of oxidative stress and cell apoptosis and finally result in lung injury.
文摘The role of the hypoxia-inducible factor(HIF)subunits 1α and 2α in response to hypoxia is well established in lungepithelial cells,whereas little is known about HIF-3α with respect to transcriptional and translational regulation by hy-poxia.HIF-3α and HIF-1α are two similar but distinct basic helix-loop-helix-PAS proteins,which have been postulatedto activate hypoxia responsive genes in response to hypoxia.Here,we used quantitative real time RT-PCR and immu-noblotting to determine the activation of HIF-3α vs.HIF-1α by hypoxia.HIF-3α was strongly induced by hypoxia(1%O_2)both at the level of protein and mRNA due to an increase in protein stability and transcriptional activation,whereasHIF-1α protein and mRNA levels enhanced transiently and then decreased because of a reduction in its mRNA stabilityin A549 cells,as measured on mRNA and protein levels.Interestingly,HIF-3α and HIF-1α exhibited strikingly similarresponses to a variety of activating or inhibitory pharmacological agents.These results demonstrate that HIF-3α is ex-pressed abundantly in lung epithelial cells,and that the transcriptional induction of HIF-3α plays an important role in theresponse to hypoxia in vitro.Our findings suggest that HIF-3α,as a member of the HIF system,is complementary ratherthan redundant to HIF-1α induction in protection against hypoxic damage in alveolar epithelial cells.
基金This work was supported by the National Natural Science Foundation Committee of China[grant numbers 81373444,81570142,81670018]the Chinese Ministry of Science and Technology[grant number 2016YFA0101300]the Key Grant from the Chongqing Science and Technology Commission[grant number cstc2014yykfC10003].
文摘Alveolar epithelial cells(AECs)injury and failed reconstitution of the AECs barrier are both integral to alveolar flooding and subsequent pulmonary fibrosis(PF).Nevertheless,the exact mechanisms regulating the regeneration of AECs post-injury still remain unclear.SMARCA4 is a part of the large ATP-dependent chromatin remodelling complex SWI/SNF,which is essential for kidney and heart fibrosis.We investigates SMARCA4 function in lung fibrosis by establishing PF mice model with bleomycin firstly and found that the expression of SMARCA4 was mainly enhanced in alveolar type II(ATII)cells.Moreover,we established an alveolar epithelium-specific SMARCA4-deleted SP-C-rtTA/(tetO)7-Cre/SMARCA4f/f mice(SOSM4D/D)model,as well as a new SMARCA4-deleted alveolar type II(ATII)-like mle-12 cell line.We found that the bleomycin-induced PF was more aggressive in SOSM4D/D mice.Also,the proliferation of ATII cells was decreased with the loss of SMARCA4 in vivo and in vitro.In addition,we observed increased proliferation of ATII cells accompanied by abnormally high expression of SMARCA4 in human PF lung sections.These data uncovered the indispensable role of SMARCA4 in the proliferation of ATII cells,which might affect the progression of PF.
基金the National Natural Science Foundation of China(82020108021 and 81530063)the Projects of the State Key Laboratory of Trauma,Burns and Combined Injury(SKLYQ201901)+1 种基金the Chongqing Science and Technology Talents,Chongqing Special Project for Academicians(cstc2020yszx-jcyjX0004)the Training Plan for Innovation Ability on the Frontiers of Military Medical Research(2019CXJSB014).
文摘Purpose:The incidence of acute lung injury(ALI)in severe trauma patients is 48%and the mortality rate following acute respiratory distress syndrome evolved from ALI is up to 68.5%.Alveolar epithelial type 1 cells(AEC1 s)and type 2 cells(AEC2s)are the key cells in the repair of injured lungs as well as fetal lung development.Therefore,the purification and culture of AECls and AEC2s play an important role in the research of repair and regeneration of lung tissue.Methods:Sprague-Dawley rats(3-4 weeks,120-150 g)were purchased for experiment.Dispase and DNase I were jointly used to digest lung tissue to obtain a single-cell suspension of whole lung cells,and then magnetic bead cell sorting was performed to isolate Tla positive cells as AECls from the single-cell suspension by using polyclonal rabbit anti-Tla(a specific AECls membrane protein)antibodies combined with anti-rabbit IgG microbeads.Afterwards,alveolar epithelial cell membrane marker protein EpCAM was designed as a key label to sort AEC2s from the remaining Tla-neg cells by another positive immunomagnetic selection using monoclonal mouse anti-EpCAM antibodies and anti-mouse IgG microbeads.Cell purity was identified by immunofluorescence staining and flow cytometry.Resii沾••The purity of AECls and AEC2s was 88.3%±3.8%and 92.6%±2.7%,respectively.The cell growth was observed as follows:AECls stretched within the 12-16 h,but the cells proliferated slowly;while AEC2s began to stretch after 24 h and proliferated rapidly from the 2nd day and began to differentiate after 3 days.Conclusion:AECls and AEC2s sorted by this method have high purity and good viability.Therefore,our method provides a new approach for the isolation and culture of AECls and AEC2s as well as a new strategy for the research of lung repair and regeneration.
