CHOP overexpression sensitizes human non-small cell lung cancer cells to cisplatin treatment by Bcl-2/JNK pathway.

C/EBP homologous protein (CHOP), a 29 kDa cellular protein, plays a role in regulating tumor proliferation, differentiation, metabolism, cell death, and in tumor resistance to chemotherapy. Non-small cell lung cancer (NSCLC) is a tumor of the respiratory system and drug resistance is prevalent among NSCLC clinical cell cultures. Herein, our study elucidated the effect of CHOP on NSCLC cells with cisplatin resistance and its mechanism. In a NSCLC cell line with cisplatin-resistance, CHOP expression was decreased, compared with A549 cells. Overexpression of CHOP decreased the cell viability and enhanced cell apoptosis in the cells treated with cisplatin. Expression of CHOP also inhibited the cell proliferation and metastasis. CHOP increased the therapeutic effect of cisplatin on NSCLC cells through the Bcl-2/JNK pathway. In summary, CHOP regulated cisplatin resistance in cells of NSCLC by promoting the expression of apoptotic proteins and inhibiting the Bcl-2/JNK signaling pathway, indicating the antitumor effects of CHOP.

α1-Antitrypsin alleviates inflammation and oxidative stress by suppressing autophagy in asthma.

BACKGROUND: Asthma is considered an incurable disease, although many advances have been made in asthma treatments in recent years. Therefore, elucidating the pathological mechanisms and seeking novel and effective therapeutic strategies for asthma are urgently needed. METHODS: Airway resistance was measured by whole-body plethysmography. H&E staining was used to observe the morphological changes in the lung. Oxidative stress was assessed by measuring the levels of MDA, CAT and SOD. Gene expression was analysed by western blotting and RT-qPCR. ELISA was used to analyse the concentrations of IL-4, IL-5 and IFN-γ. RESULTS: In the present study, we successfully established in vivo and in vitro asthma models. OVA administration led to elevated lung resistance, cell counts in BALF, and cytokine secretion, impaired airway structure and enhanced oxidative stress and autophagy in a mouse model of asthma, while IL-13 induced inflammation, oxidative stress and autophagy in BEAS-2B cells. A1AT reduced lung resistance and cell counts in BALF and suppressed inflammation, oxidative stress and autophagy in a mouse model of asthma and IL-13-induced BEAS-2B cells. Mechanistic investigations revealed that autophagy activation compromised the protective effect of A1AT on IL-13-induced BEAS-2B cells. Further mechanistic studies revealed that A1AT alleviated inflammation and oxidative stress by inhibiting autophagy in the context of asthma. CONCLUSION: We demonstrated that A1AT could alleviate inflammation and oxidative stress by suppressing autophagy in the context of asthma and thus ameliorate asthma. Our study revealed novel pathological mechanisms and provided novel potential therapeutic targets for asthma treatment.

The methylation profiles of PRDM promoters in non-small cell lung cancer.

BACKGROUND: Non-small cell lung cancer (NSCLC) is one of the leading malignant tumors worldwide. Aberrant gene promoter methylation contributes to NSCLC, and PRDM is a tumor suppressor gene family that possesses histone methyltransferase activity. This study aimed to investigate whether aberrant methylation of PRDM promoter is involved in NSCLC. MATERIALS AND METHODS: Primary tumor tissues, adjacent nontumorous tissues, and distant lung tissues were collected from 75 NSCLC patients including 52 lung squamous cell carcinoma (LSCC) patients and 23 lung adenocarcinoma patients. The expression of PRDMs was detected by polymerase chain reaction (PCR), Western blot, and immunohistochemical analysis. The methylation of PRDM promoters was detected by methylation-specific PCR. The correlation of methylation and expression of PRDMs with clinicopathological characteristics of patients were analyzed. RESULTS: mRNA expression of PRDM2, PRDM5, and PRDM16 was low or absent in tumor tissues compared to distant lung tissues. The methylation frequencies of PRDM2, PRDM5, and PRDM16 in tumor tissues were significantly higher than those in distal lung tissues. In LSCC patients, methylation of PRDM2 and PRDM16 was correlated with smoking status and methylation of PRDM5 was correlated with tumor differentiation. CONCLUSION: The expression of PRDM2, PRDM5, and PRDM16 is low or absent in NSCLC, and this is mainly due to gene promoter methylation. Smoking may be an important cause of PRDM2 and PRDM16 methylation in NSCLC.

Endoplasmic Reticulum Stress Induces HRD1 to Protect Alveolar Type II Epithelial Cells from Apoptosis Induced by Cigarette Smoke Extract.

BACKGROUND/AIMS: Cigarette smoking is a major risk factor of chronic obstructive pulmonary disease. This study aimed to examine the effects of cigarette smoke extract (CSE) on alveolar type II epithelial cells (AECII) and investigate the underlying mechanism. METHODS: Primary AECII were isolated from rat lung tissues and exposed to CSE. Apoptosis was detected by flow cytometry. Protein expression was detected by Western blot analysis. RESULTS: Primary rat AECII maintained morphological and physiological characteristic after 3 passages. CSE increased the expression of ER specific pro-apoptosis factors CHOP and caspase 12, and the phosphorylation of JNK in AECII. CSE activated ER stress signaling and increased the phosphorylation of PERK, eIF2α and IRE1. Furthermore, CSE induced the expression of Hrd1, a key factor of ER-associated degradation, in AECII. Knockdown of Hrd1 led to more than 2 fold increase of apoptosis, while overexpression of Hrd1 attenuated CSE induced apoptosis of AECII. CONCLUSIONS: Our results suggest that ER stress induces HRD1 to protect alveolar type II epithelial cells from apoptosis induced by CSE.

Bevacizumab induces A549 cell apoptosis through the mechanism of endoplasmic reticulum stress in vitro.

AIMS: To observe the effect of bevacizumab on human A549 cells and explore its mechanism. METHODS: After different concentrations (0 µM, 1 µM, 5 µM, 25 µM) of bevacizumab treating in A549 cells, CCK8 assay detect the impact of bevacizumab on A549 cell proliferation and flow cytometry determine the effect of bevacizumab on human A549 cells apoptosis. Real-time PCR and Western blotting detect the changing expression of the target gene (CHOP, caspase-4, IRE1, XBP-1) on mRNA and Protein level. RESULTS: Treatment with bevacizumab for 24-hr have induced cell death in a does-dependent manner dramatically (P<0.05). In terms of the mRNA level, expression of XBP-1 has increased obviously in each group (1 µM, 5 µM, 25 µM) (P<0.01); the expression of CHOP (25 µM) and caspase-4 (5 µM) have increased slightly (P<0.05). In terms of the protein level, the expression of CHOP has increased obviously in each group (1 µM, 5 µM, 25 µM) when compared with the control group (0 µM) (P<0.05). As for caspase-4 (5 µM, 25 µM), the expression have increased slightly when compared with the control group (0 µM) (P<0.05). CONCLUSION: Bevacizumab can induce A549 cell apoptosis through the mechanism of endoplasmic reticulum stress.

Methylation of PRDM2, PRDM5 and PRDM16 genes in lung cancer cells.

AIMS: To investigate the changes of expression and methylation status of PRDM2, PRDM5, PRDM16 in lung cancer cells after treatment with demethylation agent. METHODS: A549 (lung adenocarcinoma cell line), HTB-182 (lung squamous cell carcinoma cell line) and HBE (normal bronchial cell line) were treated with 5-aza-2dC. The methylation state of PRDM2, PRDM5, PRDM16 was detected by MSP. The expression of PRDM2, PRDM5, PRDM16 was detected by RT-PCR and Western blot analysis. Cell growth was detected by MTT assay. RESULTS: 5-aza-2-dC reduced the methylation of PRDM2, PRDM5, PRDM16 gene in A549 and HTB-182 cells but not in HBE cells. Consistently, 5-aza-2dC increased mRNA and protein expression of PRDM2, PRDM5, PRDM16 in A549 and HTB-182 cells but not in HBE cells. Furthermore, 5-aza-2dC inhibited the growth of A549 and HTB-182 cells but not HBE cells. CONCLUSIONS: PRDM2, PRDM5, PRDM16 promoters are methylated and their expression is suppressed in lung cancer cells. Demethylation drug 5-aza-2dC could upregulate the expression of PRDM2, PRDM5, PRDM16 and suppress lung cancer cell growth. 5-aza-2dC has potential to be used for lung cancer therapy by epigenetic mechanism.

Promoter methylation-mediated downregulation of PRDM5 contributes to the development of lung squamous cell carcinoma.

PRDM5 has been proposed as a tumor suppressor frequently downregualted in tumor. In this study, lung squamous cell carcinoma tissues and adjacent nontumorous normal tissues were collected from 30 patients. PRDM5 expression was detected by reverse transcription polymerase chain reaction and Western blot analysis, DNA methylation of PRDM5 promoter was analyzed by methylation-specific PCR. SK-MES-1 cells or xenografts in nude mice were treated with 5-aza-2'-deoxycitydine, and cell proliferation and tumor growth in nude mice were examined. We found that PRDM5 promoter was methylated and PRDM5 expression at both mRNA and protein levels was reduced in lung squamous cell carcinoma tissues. Furthermore, PRDM5 promoter methylation was significantly correlated with tumor differentiation and lymph node metastasis of lung squamous cell carcinoma, but not with age, gender, smoking, or tumor grade. 5-aza-2'-deoxycitydine inhibited the proliferation of SK-MES-1 cells and the growth of xenografts in nude mice, accompanied by reduced methylation of PRDM5 promoter and increased expression of PRDM5. Taken together, our data suggest that PRDM5 is a tumor suppressor in lung cancer and is a promising target for the diagnosis, prognosis, and therapy of lung squamous cell carcinoma.

[The expression of hypoxia-inducible factor-1alpha and its hydroxylases in pulmonary arteries of patient with chronic obstructive pulmonary disease].

OBJECTIVE: To observe the expression of hypoxia-inducible factor-lalpha subunit (HIF-1alpha), HIF prolyl hydroxylase domain-containing protein(PHDs) and factor inhibiting HIF-1(FIH) in pulmonary arteries of patient with chronic obstructive pulmonary disease (COPD). METHODS: Pulmonary specimens were obtained from patients undergoing lobectomy for lung cancer, 12 had concurrent COPD (COPD group) and 14 without COPD (control group). The ratio of vascular wall area to total vascular area (WA%) and pulmonary artery media thickness (PAMT) was observed, and HIF-1alpha and its hydroxylases(PHD1, PHD2, PHD3, FIH) mRNA and protein were detected by in situ hybridization and immunohistochemistry respectively. RESULTS: WA% and PAMT of COPD patients(50 microm +/- 9 microm, 40% +/- 5%, were statistically different from those of the control subjects (39 microm +/- 6 microm, 31% +/- 4%, P < 0.01). Relative quantification of mRNA and protein levels (absorbance, A) showed that HIF-lalpha mRNA and protein levels in COPD group (0.230 +/- 0.036,0.275 +/- 0.039) were statistically higher than those of the control subjects (0.174 +/- 0.029, 0.102 +/- 0.015, P < 0.01 ), and that the protein level increased more markedly. PHD1 mRNA in COPD subjects (0.180 +/- 0.030) was comparable to that in control group (0.191 +/- 0.029, P > 0.05); PHD2 and PHD3 mRNA levels in COPD (0.245 +/- 0.044, 0.252 +/- 0.023) were significantly higher than those in control group(0.182 +/- 0.028, 0.127 +/- 0.017, P < 0.01). On the other hand, in COPD subjects PHD1 protein (0.104 +/- 0.015) was significantly lower(P < 0.01), whereas PHD2 protein (0.274 +/- 0.044) was significantly higher(P < 0.01) than those in control group(0.209 +/- 0.023, 0.219+/- 0.043). As for PHD3 protein, no significant changes were observed between the two groups (0.161+/- 0.023 in COPD, 0.146 +/- 0.021 in control, P > 0.05). FIH mRNA and protein both showed no differences between the two groups. Linear correlation analysis showed that HIF1alpha protein was positively correlated with WA%, PAMT, PHD2 mRNA and protein, PHD3 mRNA, and that HIF1alpha protein was negatively correlated with PHD1 protein. CONCLUSION: PHDs may be involved in the process of hypoxic pulmonary vascular remodeling in COPD via regulation of HIF-1alpha gene expression

[The expression and possible role of SENP1 in the pulmonary vascular wall of rat during the development of hypoxic pulmonary hypertension].

OBJECTIVE: To investigate the dynamic expression and role of SENP1 (SUMO-specific proteases-1) in the pulmonary vascular wall of rat during the development of hypoxic pulmonary hypertension (HPH). METHODS: Forty adult male Wistar rats were randomly divided into 5 groups (n = 8), and exposed to normoxia (Control group) or exposed to hypoxia for 3, 7, 14 or 21 d, respectively. The HPH models were established by normobaric intermittent hypoxia. Mean pulmonary arterial pressure (mPAP), right ventricle hypertrophy index (RVHI), and vessel morphometry were measured. Reverse transcriptase-polymerase chain reaction(RT-PCR) and in situ hybridization were used to determine the mRNA expression of SENP1. Immunohistochemistry and Western blot were used to determine the protein expression of SENP1. RESULTS: The hypoxic rats developed pulmonary vascular remodeling in pulmonary arterioles after 7 d of hypoxia exposure. Pulmonary vascular remodeling in pulmonary arterioles significantly increased after 14 d of hypoxia. The level of mPAP in hypoxic rats increased significantly after 7 d of hypoxia, reached its peak after 14 d of hypoxic exposure. RVHI was markedly increased after 14 d of hypoxia. In situ hybridization and immunohistochemical analysis showed that SENP1 mRNA and protein were positively stained in control. SENP1 mRNA expression had little changes after exposure to hypoxia compared with the control, however, SENP1 protein expression was declined gradually after 7 d of hypoxia. The results of RT-PCR and Western blot showed that the same dynamic expression of SENP1 mRNA and protein in lung tissues of rats. Linear correlation analysis showed that SENP1 protein were negatively correlated with mPAP, pulmonary vascular remodeling index and RVHI. CONCLUSION: Under chronic hypoxia, SENP1 protein can be degradated. The dynamic expression of SENP1 protein may play a role in implicating in the development of HPH.

[The effect of transcription factor KLF2 in expression of gamma-GCS depend on regulation by Nrf2 in lung of rats with chronic obstructive pulmonary disease].

OBJECTIVE: To study the expression of lung Krüppel-like transcription factor (KLF2/LKLF) in lung tissues of rats with chronic obstructive pulmonary disease (COPD) and the relationship between KLF2 and NF-E2-related factor 2 (Nrf2), and make further explore the effects of KLF2 on the expression of gamma-glutamylcysteine synthetase (gamma-GCS). METHODS: Twenty-two male SD rats were randomly divided into a COPD group (n = 10) and a normal control group (n = 11). The rat model of COPD established by cigarette smoking and intratracheal instillation of lipopolysaccharide (LPS), and lung tissues were obtained. The expressions of KLF2, Nrf2, gamma-GCS mRNA and protein in lung tissues were measured by immunohistochemistry (IHC), Western blot, in situ hybridization (ISH) and reverse transcription-polymerase chain reaction (RT-PCR). To explore the relationship between KLF2 and Nrf2 protein,we utilize the method of co-immunoprecipitation (CO-IP). RESULTS: IHC and Western blot showed that protein expressions of KLF2, Nrf2, gamma-GCS were higher in the lung tissues from rats with COPD than those in the control groups (all P < 0.05). The levels of KLF2, gamma-GCS mRNA were markedly increased in the COPD group (all P < 0.01) while Nrf2 mRNA expression in COPD group had no significant difference with that in control group ( P > 0.05). CO-IP result showed that KLF2 were obviously present in immunoprecipitates of Nrf2 (P < 0.01) . Linear correlation analysis showed that the level of KLF2 protein was positively correlated with the level of Nrf2 protein (P < 0.05), and KLF2, Nrf2 proteins were positively correlated with gamma-GCS mRNA and protein (all P < 0.05). CONCLUSION: The expression of KLF2 is significantly up-regulated in COPD, which maybe up-regulate gamma-GCS mRNA expression by increasing Nrf2 expression and nuclear translocation against oxidative stress.

[The cooperation of OS-9 and PHDs in hypoxia-induced pulmonary hypertension of rats].

AIM: To investigate the dynamic expression of hypoxia-inducible factor 1alpha, PHDs and OS-9 in pulmonary arteries of rats with hypoxia-induced pulmonary hypertension. METHODS: SD rats were randomly divided into 5 groups (n = 8) and exposed to hypoxia for 0, 3, 7, 14 or 21 d, respectively. RT-PCR and in situ hybridization were used to determine the expression of mRNA. Immunohistochemistry and Western blot were used to determine the expression of protein. RESULTS: HIF-1alpha protein was poorly positive in control, markedly up-regulated after 3 d and 7 d of hypoxia (P < 0.05, vs group C), and then declined slightly after 14 d and 21 d of hypoxia. HIF-1alpha mRNA increased dramatically after 14 d of hypoxia (P < 0.05, vs group C). PHD1, PHD2 mRNA and protein was positive in group C. PHD2 mRNA and protein were up-regulated after 3 d of hypoxia (P < 0.05, vs group C), reaching its peak after 14 d of hypoxia while PHD1 protein declined after 14 d of hypoxia (P < 0.05, vs group C) without statistic mRNA changing. PHD3 mRNA and protein were detected at low level in control, markedly up-regulated after 3 d of hypoxia (P < 0.05, vs group C), and then PHD3 mRNA kept at high level while PHD3 protein declined after 14 d of hypoxia (P < 0.05, vs 7 d). OS-9 mRNA was positively in control, markedly decreased after 3 d of hypoxia (P < 0.05, vs group C), reaching its lowest lever after 14 d of hypoxia. Linear correlation analysis showed that OS-9 protein was positively correlated with OS-9 mRNA (r = 0.82, P < 0.01) and HIF-1alpha protein (r = 0.57, P < 0.01). CONCLUSION: HIF-1alpha, PHDs and OS-9 are all involved in the pathogenesis of hypoxic pulmonary hypertension in rats. OS-9 may interact with both HIF-1alpha and PHDs to promote PHD-mediated hydroxylation of HIF-1alpha.

[The preventative effects of protein tyrosine kinase on the inflammation and airway remondeling in lung of guinea pigs with bronchial asthma].

AIM: To investigate the effects of protein tyrosine kinase on the inflammation and airway remodeling in lung of guinea pigs with bronchial asthma. METHODS: 30 adult male guinea pigs were randomly divided into 3 groups (n=3): control group (C group), asthmatic group(A group)and genistein group (B group). Asthmatic model was established by ovalbumin intraperitoneal injection and ovalbumin inhalation. The total cell and the proportion of inflammatory cell in bronchial alveolar lavage fluid(BALF), inflammatory cell infiltration and index of remodeling of bronchiole were measured, respectively. The expression of p-tyrosine in lung tissue was examined by immunohistochemistry. RESULTS: The total cell and proportion of eosinophil in BALF of A group were significantly higher than that of C group (P < 0.01), but compared with A group, the total cell and proportion of eosinophil in BALF of B group were much lower (P < 0.01). The number of eosinophile and lymphocyte of bronchiole in A group were significantly higher than that of C group (P < 0.01), but compared with A group, the number of eosinophile and lymphocyte in bronchiole of B group were much lower (P < 0.01). Compared with A group, the remodeling of bronchiole of B group was significantly relieved (P <0.01), there was no difference between B and C group (P > 0.05). Immunohistochemistry indicated that in A group the p-tyrosine was more positively expressed at the bronchial smooth muscle, bronchial epithelium, smooth muscle of vessel and inflammatory cell, especially at smooth muscle of bronchi and vessel and inflammatory cell than that of C group (P <0.01), there was no difference between B group and C group (P > 0.05). CONCLUSION: PTK played a key role in inflammation and bronchial remodeling in lung of guinea pigs with bronchial asthma. The Protein tyrosine kinase inhibitor genistein could prevent and inhibit the inflammation and bronchial remodeling in lung of guinea pigs with bronchial asthma.

[Roles of NRF2 regulating gamma-glutamylcysteine synthetase in lung of rats with chronic obstructive pulmonary disease].

AIM: To investigate the expression and relationship of gamma-glutamylcysteine synthetase (gamma-GCS) and NF-E2-related factor2 (NRR2) in lung of rat with chronic obstructive pulmonary disease (COPD)in order to elucidate the possible important role of gamma-GCS and NRF2 in pathogenesis of COPD. METHODS: The rat COPD model was established by intratracheal instillation of lipopolysaccharide twice and exposed to cigarette smoke daily. The gamma-GCS activity was measured, the expression of gamma-GCS mRNA in lung was examined by in situ hybridization (ISH) and reverse transcription-polymerase chain reaction (RT-PCR), the protein expressions of NRF2, gamma-GCS in lung were detected by immunohistochemical (IH) and Western blot respectively. RESULTS: The gamma-GCS activity was higher in COPD group than that in control group. The expressions of gamma-GCS mRNA in COPD group was stronger than those in control group. ISH showed that the gamma-GCS mRNA was expressed in alveolar epithelium and bronchial smooth muscle cell in COPD. The protein expressions of NRF2, gamma-GCS were significantly higher than the control group. IH showed that NRF2, gamma-GCS proteins were expressed in alveolar and bronchial epithelium in the COPD group. There was a positive correlation between NRF2 and gamma-GCS and gamma-GCS mRNA. CONCLUSION: NRF2 may play an important role in the mechanism of COPD oxidative stress vis up-regulation of gamma-GCS.

[Reciprocal regulation between hypoxia-inducible factor-1alpha and its prolyl hydroxylases in hypoxic pulmonary hypertension rats].

OBJECTIVE: To investigate the interaction between hypoxia-inducible factors-1alpha subunit (HIF-1alpha) and its three prolyl hydroxylases (PHD1, PHD2 and PHD3) during the development of rat hypoxic pulmonary hypertension. METHODS: Forty male SD rats were randomly divided into 5 groups and exposed to normoxia (C group) or exposed to hypoxia for 3, 7, 14 or 21 d (H(3), H(7), H(14), H(21) group), respectively. Mean pulmonary arterial pressure (mPAP), vessel morphometry and right ventricle hypertrophy index (RVHI) were measured. Reverse transcriptase-polymerase chain reaction (RT-PCR) and in situ hybridization were used to determine the expression of mRNA. Immunohistochemistry and Western blot were used to determine the expression of mRNA. RESULTS: The level of mPAP [(21.7 +/- 2.4) mm Hg, 1 mm Hg = 0.133 kPa], the ratio of vascular wall thickness to external diameter [WA%, (43.9 +/- 5.3)%] and pulmonary artery media thickness [PAMT, (10.0 +/- 0.7) microm] were significantly higher in H(7) group than those in C group [(16.6 +/- 1.6) mm Hg, (36.3 +/- 4.8)% and (8.5 +/- 1.3) microm respectively, q value were 5.591, 4.082, 2.929, respectively, all P < 0.05]. These parameters reached a high level and remained stable on H(14) group, and RVHI was significantly higher in H(14) group [(27.6 +/- 1.4)%] than in C group [(23.6 +/- 2.9)%, q = 5.817, P < 0.05]. HIF-1alpha protein was barely positive in C group (0.080 +/- 0.009), but markedly up-regulated in H(3) group (0.196 +/- 0.018, compared with C group q = 18.864, P < 0.05), reaching its peak in H(7) group (0.203 +/- 0.022), and then declined slightly in H(14) and H(21) group. HIF-1alpha mRNA increased marginally in H(14) group (0.176 +/- 0.019, compared with C group q = 5.401, P < 0.05, 0.139 +/- 0.017). PHD1 and PHD2 mRNA (0.260 +/- 0.031, 0.196 +/- 0.023) and protein (0.244 +/- 0.030, 0.205 +/- 0.025) were positive in C group. PHD2 mRNA and protein were up-regulated in H(3) group (0.246 +/- 0.023, 0.235 +/- 0.025, compared with C group q value was 5.268, 3.046, respectively, all P < 0.05), reaching its peak in H(14) group whereas PHD1 protein declined in H(14) group (0.210 +/- 0.023, compared with C group q = 3.885, P < 0.05) without significant mRNA change. PHD3 mRNA and protein were detected at low level in C group (0.110 +/- 0.013, 0.153 +/- 0.019), but markedly up-regulated in H(3) group (0.259 +/- 0.024, compared with C group q = 15.831, P < 0.05), and then PHD3 mRNA remained at high level while PHD3 protein declined in H(14) and H(21) group (0.206 +/- 0.025, 0.189 +/- 0.019, compared with H(7) group q value was 6.441, 8.526, respectively, all P < 0.05). Linear correlation analysis showed that HIF-1alpha mRNA and protein were positively correlated with mPAP. There was a positive correlation between HIF-1alpha protein and PHD2, PHD3 mRNA (r value was 0.580, 0.690, respectively, all P value was 0.000) but a negative correlation between HIF-1alpha protein and PHD2 protein (r = -0.704, P < 0.05). CONCLUSIONS: HIF-1alpha was regulated mainly at the protein level during the development of hypoxic pulmonary hypertension. PHD2 and PHD3 are inducible by hypoxia, possibly via elevated HIF-1alpha, suggesting that a hypoxic up-regulation of PHD acts via feedback mechanism to attenuate hypoxia induced responses. PHD may also be regulated by posttranscriptional mechanisms.

Differential and reciprocal regulation between hypoxia-inducible factor-alpha subunits and their prolyl hydroxylases in pulmonary arteries of rat with hypoxia-induced hypertension.

Hypoxia-inducible factor (HIF)-alpha subunits (HIF-1alpha, HIF-2alpha and HIF-3alpha), which play a pivotal role during the development of hypoxia-induced pulmonary hypertension (HPH), are regulated through post-translational hydroxylation by their three prolyl hydroxylase domain-containing proteins (PHD1, PHD2 and PHD3). PHDs could also be regulated by HIF. But differential and reciprocal regulation between HIF-alpha and PHDs during the development of HPH remains unclear. To investigate this problem, a rat HPH model was established. Mean pulmonary arterial pressure increased significantly after 7 d of hypoxia. Pulmonary artery remodeling index and right ventricular hypertrophy became evident after 14 d of hypoxia. HIF-1alpha and HIF-2alpha mRNA increased slightly after 7 d of hypoxia, but HIF-3alpha increased significantly after 3 d of hypoxia. The protein expression levels of all three HIF-alpha were markedly upregulated after exposure to hypoxia. PHD2 mRNA and protein expression levels were upregulated after 3 d of hypoxia; PHD1 protein declined after 14 d of hypoxia without significant mRNA changes. PHD3 mRNA and protein were markedly upregulated after 3 d of hypoxia, then the mRNA remained at a high level, but the protein declined after 14 d of hypoxia. In hypoxic animals, HIF-1alpha proteins negatively correlated with PHD2 proteins, whereas HIF-2alpha and HIF-3alpha proteins showed negative correlations with PHD3 and PHD1 proteins, respectively. All three HIF-alpha proteins were positively correlated with PHD2 and PHD3 mRNA. In the present study, HIF-alpha subunits and PHDs showed differential and reciprocal regulation, and this might play a key pathogenesis role in hypoxia-induced pulmonary hypertension.

[The relationship between the polymorphism of glutamate cysteine ligase modulatory subunit gene and the susceptibility to chronic obstructive pulmonary disease].

OBJECTIVE: To investigate whether glutamate cysteine ligase modulatory (GCLM) subunit gene polymorphism is associated with susceptibility to chronic obstructive pulmonary disease (COPD), and to study the relationship between polymorphism of GCLM gene with plasma gamma-glutamylcysteine synthetase (gamma-GCS) activity. METHODS: Blood samples of 104 stable phase COPD smokers (COPD group), 124 healthy smokers (C group) and 132 healthy never-smokers (H group) were collected, and then the genotypes of GCLM -588C/T and GCLM -23C/T polymorphism sites were detected by polymerase chain reaction (PCR) and restriction fragment length polymorphism analysis (RFLP). The plasma gamma-GCS activity was measured by coupled enzyme procedure. RESULTS: (1) The distribution of -588CC, -588CT, -588TT genotypes were corresponding to -23GG, -23GT, -23TT respectively in all of the individuals. (2) The frequencies of -588CC genotype and -588 C allele were significantly lower in COPD group (62.3% and 79.2%) than in C group (84.7% and 91.9%) and H group (78.8% and 89.0%, P < 0.01). (3) In smokers, GCLM -588 T allele carried a higher risk to COPD, the odds ratio (OR value) to C allele was 3.0, and with a 95% confidence interval 1.7 - 5.3. (4) The plasma gamma-GCS activity was increased in C group [(282 +/- 58) U/mg.prot] and COPD group [(224 +/- 54) U/mg.prot] as compared with H group [(157 +/- 26) U/mg.prot, P < 0.01], and were higher in healthy smokers than in COPD smokers (P < 0.01). (5) The smokers with -588CC genotype had higher gamma-GCS activity than CT or TT genotype [(292 +/- 54), (225 +/- 45) U/mg.prot, P < 0.01 in C group and (245 +/- 52), (188 +/- 36) U/mg.prot, P < 0.01 in COPD group], but the difference did not exist in H group [(158 +/- 27), (153 +/- 25) U/mg.prot, P > 0.05]. CONCLUSION: The polymorphism of GCLM -588C/T and -23G/T sites were associated with susceptibility to COPD, and were associated with plasma gamma-GCS activity.

Transforming growth factor-beta1 induces transdifferentiation of fibroblasts into myofibroblasts in hypoxic pulmonary vascular remodeling.

The muscularization of non-muscular pulmonary arterioles is an important pathological feature of hypoxic pulmonary vascular remodeling. However, the origin of the cells involved in this process is still not well understood. The present study was undertaken to test the hypothesis that transforming growth factor-beta1 (TGF-beta1) can induce transdifferentiation of fibroblasts into myofibroblasts, which might play a key role in the muscularization of non-muscular pulmonary arterioles. It was found that mean pulmonary arterial pressure increased significantly after 7 d of hypoxia. Pulmonary artery remodeling index and right ventricular hypertrophy became evident after 14 d of hypoxia. The distribution of nonmuscular, partially muscular, and muscular vessels was significantly different after 7 d of hypoxia. Immunocytochemistry results demonstrated that the expression of a-smooth muscle actin was increased in intra-acinar pulmonary arteries with increasing hypoxic time. TGF-beta1 mRNA expression in pulmonary arterial walls was increased significantly after 14 d of hypoxia, but showed no obvious changes after 3 or 7 d of hypoxia. In pulmonary tunica adventitia and tunica media, TGF-beta1 protein staining was poorly positive in control rats, but was markedly enhanced after 3 d of hypoxia, reaching its peak after 7 d of hypoxia. The myofibroblast phenotype was confirmed by electron microscopy, which revealed microfilaments and a well-developed rough endoplasmic reticulum. Taken together, our results suggested that TGF-beta1 induces transdifferentiation of fibroblasts into myofibroblasts, which is important in hypoxic pulmonary vascular remodeling.

[Effects of Nrf2 on gamma-glutamylcysteine synthase in lung of guinea pigs with bronchial asthma].

AIM: To investigate the effects of Nrf2 (Nuclear-E2 related factor) on gamma-glutamylcysteine synthase (gamma-GCS) in lung of guinea pigs with bronchial asthma. METHODS: 20 adult male guinea pigs were randomly divided into two groups (n = 10): control group (C group) and asthmatic group (A group), asthmatic model was established by ovalbumin intraperitoneal and ovalbumin inhalation. The reactive oxygen piece (ROS), reduced glutathione (GSH), oxidant glutathione (GSSG) and total GSH in lung tissue were examined respectively. Inflammatory cell infiltration and index of remodeling of bronchiole were detected. In situ hybridization detected the gamma-GCS heavy subunit (gamma-GCS h) mRNA in lung tissue. Immunohistochemistry detected the expression of Nrf2 protein and gamma-GCS protein in lung tissue. RT-PCR measured the expression of Nrf2 mRNA in lung tissue. The activity of gamma-GCS was measured by coupled enzyme assay. RESULTS: (1) The number of eosinophils and lymphocytes in bronchiole of A group were significantly higher than that of C group (P < 0.05), the remodeling of bronchiole in A group was definite. (2) ROS (U/mg pro), GSSG (micromol/g pro) and total GSH in lung tissue of A group were significantly higher than that of C group (P < 0.01). The GSH/GSSG in lung tissue of A group was much lower than that of C group (P < 0.01), GSH in lung tissue showed no difference between A group and C group. (3) Immunohistochemistry indicated that Nrf2 protein and gamma-GCS protein were more positively expressed in A group than that in C group (P < 0.01). In situ hybridization discovered that the expression of gamma-GCS-h mRNA in lung tissue of A group was more positive than that of C group. (4) RT-PCR showed that the expression of Nrf2 mRNA was no difference between A group and C group (P > 0.05). (5) The activity of gamma-GCS of A group was (28 +/- 8)U which was significantly higher than that of C group (9 +/- 2)U (P < 0.01). (6) Linear correlation analysis indicated that in lung tissue of guinea pig with asthma there existed strongly positive relationship among ROS, GSSG and the expression of Nrf2, gamma-GCS mRNA, gamma-GCS protein, the activity of gamma-GCS, there existed strongly negative relationship among GSH/GSSG and the expression of Nrf2, gamma-GCS mRNA, gamma-GCS protein, the activity of gamma-GCS. CONCLUSION: There existed oxidative stress in lung of guinea pigs with bronchial asthma, which possibly positively regulated gamma-GCS via up regulating transcription factor Nrf2.