Retinoic acid reduces kidney injury by regulating oxidative stress, NRF-2, and apoptosis in hyperoxic mice.

Nuclear factor-erythroid-2-related factor-2 (NRF-2) is a cellular resistance protein to oxidants. We investigated the effect of exogenous all-trans retinoic acid (ATRA) on the antioxidant system and NRF-2 in mice kidneys under hyperoxia-induced oxidative stress. Mice were divided into four groups. Daily, two groups were given either peanut-oil/dimethyl sulfoxide (PoDMSO) mixture or 50 mg/kg ATRA. Oxidative stress was induced by hyperoxia in the remaining groups. They were treated with PoDMSO or ATRA as described above, following hyperoxia (100% oxygen) for 72 h. NRF-2 and active-caspase-3 levels, lipid peroxidation (LPO), activities of antioxidant enzymes, xanthine oxidase (XO), paraoxonase1 (PON1), lactate dehydrogenase (LDH), tissue factor (TF), and prolidase were assayed in kidneys. Hyperoxia causes kidney damage induced by oxidative stress and apoptosis. Increased LPO, LDH, TF, and XO activities and decreased PON1 and prolidase activities contributed to kidney damage in hyperoxic mice. After hyperoxia, increases in the activities of antioxidant enzymes and NRF-2 level could not prevent this damage. ATRA attenuated damage via its oxidative stress-lowering effect. The decreased LDH and TF activities increased PON1 and prolidase activities, and normalized antioxidant statuses are indicators of the positive effects of ATRA. We recommend that ATRA can be used as a renoprotective agent against oxidative stress induced-kidney damage.

Evaluation of Fatty Acid Contents and Biological Activities of Jurinea turcica.

The fatty acid profile, antioxidant/antibacterial, and cytotoxic effects of the extracts obtained from Jurinea turcica B.Dogan& A.Duran have been evaluated for the first time in the current study. The fatty acid profile of ethanolic extracts was determined using the Soxhlet extractor by a gas chromatography-mass spectrometer. The antioxidant and antibacterial activities were measured by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and ferrous reduction tests and the disc diffusion technique. Additionally, the cytotoxicity and wound healing assays were performed on A549 cells. The highest amount of component in the leaf extract was docosanoic acid methyl ester, whereas abundant arachidonic acid methyl ester was mainly found in the flower extract. The IC50 values, the 50 % scavenging value for the DPPH radical, were 179.13 and 124.67 µg/mL for the leaf and flower extracts, respectively. IC50 values (the half-maximal inhibitory concentration) were 10.4 and 24.7 µg/mL for the flower and leaf extracts, respectively. The leaf extract showed more potent antibacterial activity on Enterococcus faecalis (17 mm) and Staphylococcus aureus (16 mm) bacteria than the flower extract. In conclusion, the extracts of J. turcica have anti-cancerogenic and antibacterial effects. Leaf extracts have antibacterial and anti-metastatic effects, while flower extracts show antioxidant, cytotoxic, and apoptotic properties in A549 cells.

CGRP induces myofibroblast differentiation and the production of extracellular matrix in MRC5s via autocrine and paracrine signalings.

There are contradictory views on which calcitonin gene-related peptide (CGRP) causes pulmonary fibrosis. Fibrotic potency of CGRP was tested and compared to that of transforming growth factor-ß (TGF-ß). Myofibroblast differentiation, cell proliferation, and activations of TGF-ß and Wnt pathways were examined for 24, 48, and 72 h in A549 and MRC5 cell lines stimulated with CGRP and TGF-ß. CGRP-induced cell proliferation in MRC5s early on while cell proliferation in A549 occurred progressively. CGRP promoted fibroblast-myofibroblast differentiation by inducing the transcription of ACTA2, COL1A1, SMAD2/3, and SMAD4 genes, the production of collagen, fibronectin, α-smooth muscle actin, and activation of TGF-ß signaling starting from 24 h. Additionally, TGF-ß signaling induced by CGRP decreased the DKK1 level and activated the Wnt signaling in MRC5s. After CGRP stimulation, Wnt7a levels were increased from 24 to 72 h, while Wnt5a levels were elevated at 72 h in MRC5s. CGRP did not induce epithelial-mesenchymal transition in A549s, unlike TGF-ß. A comparison of fibrotic potency of CGRP and TGF-ß showed that TGF-ß is a powerful profibrotic molecule and induces earlier myofibroblast differentiation. Even so, CGRP promotes myofibroblast differentiation and extracellular matrix production by inducing Smad-dependent-TGF-ß and Wnt signalings via autocrine and paracrine signalings in MRC5s.

Dysregulation of E-cadherin in pulmonary cell damage related with COPD contributes to emphysema.

Air pollution, especially at chronic exposure to high concentrations, is a respiratory risk factor for the development of chronic obstructive pulmonary disease (COPD). E-cadherin, a cell-cell adhesion protein, is involved in the integrity of the alveolar epithelium. Causes of E-cadherin decreases in emphysematous areas with pulmonary cell damage related to COPD are not well understood. We aimed to determine the molecules causing the decrease of E-cadherin and interactions between these molecules. In emphysematous and non-emphysematous areas of lungs from COPD patients (n = 35), levels of E-cadherin, HDACs, Snail, Zeb1, active-ß-catenin, p120ctn, and Kaiso were determined by using Western Blot. The interactions of HDAC1, HDAC2, and p120ctn with transcription co-activators and Kaiso were examined by co-immunoprecipitation experiments. The methylation status of the CDH1 promoter was investigated. E-cadherin, Zeb1, Kaiso, and active-ß-catenin were decreased in emphysema, while HDAC1, HDAC2, and p120ctn2 were increased. Snail, Zeb1, Twist, active-ß-catenin, Kaiso, and p120ctn co-precipitated with HDAC1 and HDAC2. E-cadherin, Kaiso, and active-ß-catenin co-precipitated with p120ctn. HDAC1-Snail and HDAC2-Kaiso interactions were increased in emphysema, but p120ctn-E-cadherin interaction was decreased. The results show that HDAC1-Snail and HDAC2-Kaiso interactions are capable of decreasing the E-cadherin in emphysema. The decreased interaction of p120ctn/E-cadherin leads to E-cadherin destruction. The decreased E-cadherin and its induced degradation in pneumocytes cause impaired repair and disintegrity of the epithelium. Approaches to suppress HDAC1-Snail and HDAC2-Kaiso interactions may help the protection of alveolar epithelial integrity by increasing the E-cadherin stability in pneumocytes.

Atorvastatin attenuates pulmonary fibrosis in mice and human lung fibroblasts, by the regulation of myofibroblast differentiation and apoptosis.

Statins have anti-inflammatory and antifibrotic effects in addition to cholesterol-lowering effect. We aimed to investigate the effect of atorvastatin (ATR) in fibrotic mouse lung and human lung fibroblasts (MRC5s). Pulmonary fibrosis was induced by a single dose of bleomycin by intratracheal instillation in adult mice. ATR was administered (20 mg/kg ip) to mice with healthy and pulmonary fibrosis for 10 days from Day 7 of the experiment. Mice were dissected on the 21st day. The levels of alpha-smooth muscle actin (α-SMA), pSMAD2/3, LOXL2, and p-Src were determined by Western blot analysis in the lungs. Furthermore, a group of MRC5 was differentiated into myofibroblasts by transforming growth factor-beta (TGF-ß). Another group of MRC5s was treated with 10 µM ATR at 24 h after TGF-ß stimulation. Cells were collected at 0, 24, 48, and 72 h. The effects of ATR on myofibroblast differentiation, apoptosis, and TGF-ß and Wnt/ß-catenin signaling activations were examined by Western blot analysis and flow cytometry in MRC5s. ATR attenuated pulmonary fibrosis by regulating myofibroblast differentiation and interstitial accumulation of collagen, by acting on LOXL2, p-Src, and pSMAD2/3 in mice lungs. Additionally, it blocked myofibroblast differentiation via reduced TGF-ß and Wnt/ß-catenin signaling and decreased α-SMA in MRC5s stimulated with TGF-ß. Moreover, ATR caused myofibroblast apoptosis via caspase-3 activation. ATR treatment attenuates pulmonary fibrosis in mice treated with bleomycin. It also inhibits fibroblast/myofibroblast activation, by both reducing myofibroblasts differentiation and inducing myofibroblast apoptosis.

Effects of combined administration of doxorubicin and chloroquine on lung pathology in mice with solid Ehrlich ascites carcinoma.

Combined use of a chemotherapeutic agent and an autophagy inhibitor is a novel cancer treatment strategy. We investigated the effects of chloroquine (CQ) on lung pathology caused by both solid Ehrlich ascites carcinoma (EAC) and doxorubicin (DXR). A control group and eight experimental groups of adult female mice were inoculated subcutaneously with 2.5 × 106 EAC cells. DXR (1.5 mg/kg and 3 mg/kg) and CQ (25 mg/kg and 50 mg/kg) alone or in combination were injected intraperitoneally on days 2, 7 and 12 following inoculation with EAC cells. Lung tissue samples were examined using immunohistochemistry (IHC) for endothelial (eNOS), inducible nitric oxide synthase (iNOS) and neutrophil gelatinase-associated lipocalin (NGAL). Serum catalase (CAT), glutathione peroxidase (GPx), superoxide dismutase (SOD) and malondialdehyde (MDA) levels were measured using ELISA. We found decreased levels of iNOS and eNOS in the groups that received 1.5 mg/kg DXR alone and in combination with 25 mg/kg and 50 mg/kg CQ. Combined administration of DXR and CQ partially prevented disruption of alveolar structure. Levels of antioxidant enzymes and MDA were lower in all treated groups; the greatest reduction was observed in mice that received the combination of 25 mg/kg CQ + 1.5 mg/kg DXR. Levels of NGAL were elevated in all treated groups. We found that CQ ameliorated both EAC and DOX induced lung pathology in female mice with solid EAC by reducing oxidative stress.

Effect of long noncoding RNAs on epithelial-mesenchymal transition in A549 cells and fibrotic human lungs.

Long noncoding RNAs (LncRNAs) regulate epithelial-mesenchymal transition (EMT). EMT involves myofibroblast differentiation and pulmonary fibrosis (PF). We aimed to determine the expression profiles of HOTAIR, CARLo-5, and CD99P1 LncRNAs in EMT-mediated myofibroblast differentiation in A549 cells and fibrotic human lungs and to explain their roles. A group of A549s was stimulated with transforming growth factor ß (TGF-ß; 5 ng/ml) to induce EMT. The remaining A549s were incubated with 20 µM FH535 after 24 h of TGF-ß treatment to inhibit EMT. A549s were collected at 0, 24, 36, and 48 h. Expressions of three LncRNAs and protein/genes related to EMT, myofibroblast differentiation, and PF were assayed by quantitative reverse-transcription polymerase chain reaction and Western blot analysis in A549s and fibrotic human lungs. The targets of three LncRNAs were investigated by bioinformatics methods. TGF-ß stimulation resulted in increased expressions of three LncRNAs, ACTA2, COL1A1, SNAI1, CTNNB1, TCF4, LEF1, α-SMA, and active-ß-catenin, and decreased E-cadherin at 24, 36, and 48 h in A549s. FH535 treatment regressed these alterations. But it increased HOTAIR expression at 36 h and did not increase E-cadherin at 48 h. Fibrotic human lungs were characterized by increased expressions of HOTAIR, CARLo-5, CD99P1, and miR-214, decreased expressions of miR-148b, miR-218-1, miR-7-1, and the presence of CARLo-5 and CD99P1 in HDAC1-LncRNAs coprecipitation products, but not HOTAIR. Bioinformatic analysis showed the interactions of three LncRNAs with both proteins and at least 13 microRNAs related to EMT and PF. In conclusion, HOTAIR, CARLo-5, and CD99P1 can regulate EMT-mediated myofibroblast differentiation through interacting with proteins and miRNAs associated with EMT and PF. These LncRNAs can be considered as potential targets to decrease EMT for treating PF.

The protective effect of vitamin U on valproic acid-induced lung toxicity in rats via amelioration of oxidative stress.

Vitamin U (Vit U) is a novel free-radical scavenger. The protective effect of Vit U on valproic acid (VPA)-induced lung damage was examined. Rats were divided into four groups: control rats; rats given Vit U (50 mg/kg/d, by gavage) for 15 days; rats treated with VPA (500 mg/kg/d, intraperitoneally) for 15 days; and rats were given VPA + Vit U (in same dose and time). On the 16th day of the experiment, the lungs were collected from rats. Lung structure, pulmonary oxidant/antioxidant parameters and Nrf2, α-SMA, and collagen-1 were evaluated by microscopic and biochemical analysis. Additionally, it was determined the interactions of Vit U with Nrf2 and Keap1 by in silico analysis. VPA administration increased lipid peroxidation and the activity of lactate dehydrogenase and myeloperoxidase. However, it decreased the glutathione level, and the activities of glutathione peroxidase, glutathione-S-transferase, catalase, and superoxide dismutase. VPA-mediated oxidative stress prompted structural distortion and fibrotic alterations in the lung. Vit U supplementation reversed structural and biochemical alterations, induced antioxidant system through Nrf2 activation, and attenuated fibrosis by reducing collagen expression in VPA-administered rats. However, Vit U pretreatment was unable to reduce α-SMA levels in the lung of VPA-treated rats. Molecular docking analysis showed the binding of Vit U to ETGE motif leads to dissociation of Nrf2 from the Nrf2/Keap1 complex and its transfer to nuclei. In conclusion, Vit U attenuated VPA-induced tissue damage by restoring antioxidative systems through amelioration of Nrf2 activity in the lung under oxidative stress.

Vitamin D modulates E-cadherin turnover by regulating TGF-ß and Wnt signalings during EMT-mediated myofibroblast differentiation in A459 cells.

Vitamin D (VitD) has an anti-fibrotic effect on fibrotic lungs. It reduces epithelial-mesenchymal transition (EMT) on tumors. We aimed to investigate target proteins of VitD for the regression of EMT-mediated myofibroblast differentiation. A group of A549 cells were treated with 5 % cigarette smoke extract (CSE) and 5 %CSE + TGF-ß (5 ng/ml) to induce EMT. The others were treated with 50 nM VitD 30 min before %5CSE and TGF-ß treatments. All cells were collected at 24, 48 and 72 h following 5 %CSE and TGF-ß administrations. The expression of p120ctn and NEDD9 proteins acted on E-cadherin turnover in addition to activations of TGF-ß and Wnt pathways were examined in these cells and fibrotic human lungs. CSE and TGF-ß induced EMT by reducing E-cadherin, p-VDR, SMAD7 and DKK1, increasing α-SMA, p120ctn, Kaiso, NEDD9 and stimulating TGF-ß and Wnt/ß-catenin signalings in A549 cells. VitD administration reversed these alterations and regressed EMT. Co-immunoprecipitation analysis revealed p-VDR interaction with ß-catenin and Kaiso in fibrotic and non-fibrotic human lungs. VitD pre-treatments reduced TGF-ß and Wnt/ß-catenin signalings by increasing p-VDR, protected from E-cadherin degradation and led to the regression of EMT in A549 cells treated with CSE and TGF-ß. Finally, VitD supplementation combined with anti-fibrotic therapeutics can be suggested for treatment of pulmonary fibrosis, which may be developed by smoking, in cases of VitD deficiency.

Gastrin-releasing peptide induces fibrotic response in MRC5s and proliferation in A549s.

Idiopathic pulmonary fibrosis (IPF) is a complex lung disease, whose build-up scar tissue is induced by several molecules. Gastrin-releasing peptide (GRP) is released from pulmonary neuroendocrine cells, alveolar macrophages, and some nerve endings in the lung. A possible role of GRP in IPF is unclear. We aimed to investigate the fibrotic response to GRP, at the cellular level in MRC5 and A549 cell lines. The proliferative and fibrotic effects of GRP on these cells were evaluated by using BrdU, immunoblotting, immunofluorescence and qRT-PCR for molecules associated with myofibroblast differentiation, TGF-ß and Wnt signalling. All doses of GRP increased the amount of BrdU incorporation in A549 cells. In contrast, the amount of BrdU increased in MRC5 cells in the first 24 h, though progressively decreased by 72 h. GRP did not stimulate epithelial-mesenchymal transition in A549 cells, rather, it stimulated the differentiation of MRC5 cells into myofibroblasts. Furthermore, GRP induced gene and protein expressions of p-Smad2/3 and Smad4, and reduced the levels of Smad7 in MRC5 cells. In addition, GRP decreased Wnt5a protein levels and stimulated ß-catenin activation by increasing Wnt4, Wnt7a and ß-catenin protein levels. GRP caused myofibroblast differentiation by inducing TGF-ßand Wnt pathways via paracrine and autocrine signalling in MRC5 cells. In conclusion, GRP may lead to pulmonary fibrosis due to its proliferative and fibrotic effects on lung fibroblasts. The abrogation of GRP-mediated signal activation might be considered as a treatment modality for fibrotic lung diseases. Video Abstract.

The effects of atorvastatin on the kidney injury in mice with pulmonary fibrosis.

OBJECTIVES: The present study investigated the effects of atorvastatin on kidney injury in mice with pulmonary fibrosis (PF). METHODS: Adult mice were divided into four groups: mice treated with intratracheal bleomycin (I) and their controls (II), and mice treated with atorvastatin for 10 days after 7 days from bleomycin treatment (III) and their controls (IV). Mice were dissected on the 21st day. KEY FINDINGS: Mononuclear cell infiltrations, injured proximal tubule epithelium and p-c-Jun level increased, while cell proliferation and the levels of p-SMAD2, ELK1, p-ELK1, p-ATF2 and c-Jun decreased in the kidney tissue of mice with PF. The atorvastatin treatments to mice with PF resulted in significant increases at the TGF-ß activation, cell proliferation and kidney damage and decreases in the levels of p-SMAD2, p-ELK1, p-ATF2 and p-c-Jun, but not change the p-SMAD3, ELK1 and ATF2 in kidneys. CONCLUSIONS: The depletion of MAPK signals, rather than SMAD signalling, is effective in kidney damage of mice with PF. Atorvastatin did not regress kidney damage in these mice, whereas it increases the kidney injury. The c-Jun-mediated JNK signals could help kidney repair through cell proliferation. The treatment time and doses of atorvastatin should be optimized for regression of kidney damage.

Exendin-4 partly ameliorates - hyperglycemia-mediated tissue damage in lungs of streptozotocin-induced diabetic mice.

Glucagon-like peptide-1 (GLP-1) stimulates insulin secretion, - plays anti-inflammatory role in atherosclerosis, and has surfactant-releasing effects in lungs. GLP-1 analogues are used in diabetes therapy. This is the first study to investigate the effects of exendin-4, a GLP-1 receptor agonist, on lung injury in diabetic mice. BALB/c male mice were divided into four groups. The first group was given only citrate buffer, the second group was given only exendin-4, the third group was given only streptozotocin (STZ), and the fourth group was given both exendin-4 and STZ. Exendin-4 (3µg/kg) was administered daily by subcutaneous injection for 30days after mice were rendered diabetic with a single dose of STZ (200mg/kg). Structural alterations, oxidative stress, apoptosis, insulin signaling and expressions of prosurfactant-C, alpha-smooth muscle actin, collagen-I and fibronectin were evaluated in lung tissue. Diabetic mice lungs were characterized by induced oxidative stress, apoptosis, edema, and cell proliferation. They had honeycomb-like alveoli, thicker alveolar walls, and hypertrophic pneumocytes. Although exendin-4 treatment improved pulmonary edema, apoptosis, oxidative stress, and lung injury, it led to the disrupted insulin signaling and interstitial collagen accumulation in the lungs of diabetic mice. Exendin-4 ameliorates hyperglycemia-mediated lung damage by reducing glucose, -oxidative stress and stimulating cell proliferation. However, exendin-4 led to increased lung injury partly by reducing insulin signaling - and collagen accumulation around pulmonary vasculature in diabetic mice.

The copper dependent-lysyl oxidases contribute to the pathogenesis of pulmonary emphysema in chronic obstructive pulmonary disease patients.

Abnormalities in the elastic fiber biology are seen in pulmonary emphysema (PE). The copper-dependent lysyl oxidases regulate the production and accumulation of elastic fibers in the connective tissue. This study focused on the relationship between lysyl oxidase (LOX), LOX-like protein 1 (LOXL1), and LOXL2 and PE pathogenesis. Lung samples with or without PE from patients with chronic obstructive lung disease (n=35) were used. Protein levels of elastin, LOX, LOXL1, LOXL2, hypoxia inducible factor 1-alpha (HIF-1α), copper metabolism domain containing-1 (COMMD1), and phosphatase and tensin homolog (PTEN) were assayed using microscopic and biochemical methods The emphysematous areas were characterized by enlargement of the alveoli, destruction of the alveolar structure, accumulation of macrophages in the alveolar lumens, and showed increased HIF-1α immunoreactivity. Additionally, the emphysematous areas had significantly lower elastin, LOX, LOXL1, LOXL2, HIF-1α, COMMD1, and PTEN protein levels than the non-emphysematous areas. We suppose that the reductions in the HIF-1α levels led to decreases in the protein levels of active LOX, LOXL1, and LOXL2. These decreases might cause abnormalities in the elastic fiber biology. HIF-1α activation induced by decreased COMMD1 and protease activation induced by decreased PTEN might contribute to the development of PE. Finally, methods aimed at increasing the protein levels of LOXs, COMMD1 and PTEN might be effective for treating PE.

The protective effects of prostaglandin E1 on lung injury following renal ischemia-reperfusion in rats.

For the purposes of the present study, the protective effect of prostaglandin E1 (PGE1) on lung injury following renal ischemia-reperfusion (RIR) was investigated. Adult male rats were divided into four groups, namely, (I) control rats given physiological saline; (II) rats given PGE1 (20 µg/kg, intravenously); (III) rats subjected to RIR; and (IV) rats subjected to RIR given PGE1 30 min prior to ischemia and just before reperfusion. The right nephrectomy was performed in the RIR model. The left renal pedicle was occluded for 60 min to induce ischemia and then the left kidney was subjected to reperfusion for 60 min. The lungs of rats were used for microscopic and biochemical analyses. Although rats subjected to RIR did not exhibit heavy degenerative alterations in the lung structure, they possessed pulmonary interstitial edema. Lung glutathione levels and catalase, superoxide dismutase, glutathione peroxidase, and tissue factor (TF) activities were decreased in rats subjected to RIR, while lung lipid peroxidation, myeloperoxidase (MPO), xanthine oxidase and serum lactate dehydrogenase (LDH) activities, and blood urea and serum creatinine levels were increased in these rats when compared with the control group. PGE1 treatments resulted in the regression of oxidative stress via induction of antioxidant system, the decreased MPO and LDH activities, the reduced urea and creatinine levels, and the induced TF activity in rats subjected to RIR, while edema still remained permanent. We conclude that PGE1 may be useful in preventing lung injury with the exception of edema that occurred as a result of RIR in rats.

Dasatinib attenuated bleomycin-induced pulmonary fibrosis in mice.

Anti-fibrotic effect of dasatinib, a platelet-derived growth factor receptor (PDGFR) and Src-kinase inhibitor, was tested on pulmonary fibrosis (PF). Adult mice were divided into four groups: mice dissected 21 d after the bleomycin (BLM) instillation (0.08 mg/kg in 200 µl) (I) and their controls (II), and mice treated with dasatinib (8 mg/kg in 100 µl, gavage) for one week 14 d after BLM instillation and dissected 21 d after instillation (III) and their controls (IV). The fibrosis score and the levels of fibrotic markers were analyzed in lungs. BLM treatment-induced cell proliferation and increased the levels of collagen-1, alpha smooth muscle actin, phospho (p)-PDGFR-alpha, p-Src, p-extracellular signal-regulated kinases1/2 and p-cytoplasmic-Abelson-kinase (c-Abl) in lungs, and down-regulated PTEN expression. Dasatinib reversed these alterations in the fibrotic lung. Dasatinib limited myofibroblast activation and collagen-1 accumulation by the inhibition of PDGFR-alpha, and Src and c-Abl activations. In conclusion, dasatinib may be a novel tyrosine and Src-kinase inhibitor for PF regression in mice.

Chard (Beta vulgaris var. cicla) extract improved hyperglycemia-induced oxidative stress and surfactant-associated protein alterations in rat lungs.

CONTEXT: Chard is used as an antidiabetic agent by the diabetic patients in Turkey. OBJECTIVE: The effect of chard extract [Beta vulgaris L. var. cicla (Chenopodiaceae)] on the antioxidant system and the expression of surfactant-associated proteins (SP) in the lungs of hyperglycemic rats were examined. MATERIALS AND METHODS: Hyperglycemia was induced by a single dose of streptozotocin (60 mg/kg) provided intraperitoneally. Fourteen days after the rats were rendered hyperglycemic, the chard (2 g/kg/d), insulin (6 U/kg/d), and chard plus insulin (as mentioned above) were administered to rats for 45 d. On day 60, rats' lungs were removed. Oxidative stress parameters and SP expression were assayed. RESULTS: The lungs of hyperglycemic rats were characterized by the induced lipid and protein oxidation, elevated myeloperoxidase and xanthine oxidase activities, decreased glutathione levels, and reduced tissue factor and antioxidant enzymes activities (catalase, superoxide dismutase, glutathione peroxidase, and glutathione-S-transferase). Chard treatment alone and chard treatment combined with insulin were capable of achieving a regression of pulmonary oxidative stress, by inhibiting lipid and protein oxidation, and restoring the antioxidant system of hyperglycemic rats. SP-A expressions were significantly unchanged in all groups, whereas pro-SP-C and SP-D expressions were reduced in hyperglycemic rats. Pro-SP-C and SP-D levels were increased by chard and insulin administrations alone and combined in hyperglycemic rats. DISCUSSION AND CONCLUSION: All treatments have a positive effect on the surfactant and antioxidant systems of the lungs of hyperglycemic rats. The best therapeutic effect was provided by treatment with chard extract alone in the compensation of hyperglycemic symptoms.

The copper chelator tetrathiomolybdate regressed bleomycin-induced pulmonary fibrosis in mice, by reducing lysyl oxidase expressions.

Pulmonary fibrosis (PF) is characterized by an increase in the number of fibroblasts and an accumulation of collagen fibers in the extracellular matrix (ECM). The members of the copper-dependent lysyl oxidase (LOX) enzyme family regulate the collagen accumulation in the ECM. Tetrathiomolybdate (TM) is a copper chelator. The present study reported the effect of TM on the expression of LOX proteins (LOX, LOXL1, and LOXL2), collagen digestion enzymes (MMP2 and MMP8), and TIMP1 (a collagenase inhibitor) in PF. The PF in mice was induced by intratracheal bleomycin instillation. Adult mice were divided into four groups: mice dissected after 21 days of the first bleomycin (0.08 mg/kg, single dose) treatment (I) and their controls (II), and mice treated with TM for 1 week (1.2 mg/day/mice for the first 4 days and 0.9 mg/day/mice for the last 3 days) after 14 days of the first bleomycin instillation and dissected in the 21st day of the experiment (III) and their controls (IV). Mice in groups III and IV were fed a low-copper (2 mg/kg) diet during the last 7 days of the experiment. The fibrosis score in the lung was determined under a microscope. The expressions of collagen-I, LOX, MMP, and TIMP1 proteins were analyzed by Western blotting in the lung. Mice lungs with fibrosis were characterized by an overexpression of collagen-I, LOX, MMP, and TIMP1 proteins in addition to an accumulation of collagen fibers. TM treatments significantly regressed the overexpression of these proteins in the fibrotic mice lung. In conclusion, TM treatments can be used for the regression of PF, by decreasing collagen-I protein expression and accumulation.

Retinoic acid induced repair in the lung of adult hyperoxic mice, reducing transforming growth factor-ß1 (TGF-ß1) mediated abnormal alterations.

The aim of the study was to determine the effects of retinoic acid on lung alveolar repair in adult hyperoxic mice and to investigate the relationship between TGF-ß1 and retinoic acid during the repair processes. Adult mice were divided into 4 groups. Two groups were given daily intraperitoneal injections of peanut oil/dimethylsulfoxide mixture and retinoic acid (50mg/kg body weight, 50 µl of volume) dissolved in peanut oil/dimethylsulfoxide mixture for 12 days with a 2-day break on days 6 and 7. Following hyperoxia (100% oxygen) for 72 h the remaining two groups were treated in the same manner as already described: peanut oil/dimethylsulfoxide mixture and retinoic acid. Lung structure was investigated by light microscopy. TGF-ß1 and Smad protein expressions in the lung were assayed by biochemical methods. Hyperoxic mice exhibited damage to the alveolar walls, increased cell proliferation and induced Smad3/TGF-ß1 signaling. Smad2 and phospho-Smad2 protein expressions were unchanged in all groups. Retinoic acid administration improved the degenerative alterations caused by hyperoxia and helped in alveolar repair. This positive effect of retinoic acid resulted from the inhibition of Smad3/TGF-ß1 signaling via reduced Smad4 mRNA and increased Smad7 protein expression. Retinoic acid also induced alveolarization and restricted Smad3/TGF-ß1 signaling by decreasing Smad4 mRNA in healthy mice. Thus, retinoic acid helped repair Smad3/TGF-ß1-induced lung damage in hyperoxic mice.

Teduglutide, a glucagon-like peptide 2 analogue: a novel protective agent with anti-apoptotic and anti-oxidant properties in mice with lung injury.

Teduglutide is a long-acting synthetic analogue of human glucagon-like peptide-2 (GLP-2). GLP-2 regulates cell proliferation and apoptosis as well as normal physiology in the gastrointestinal tract. In the present study, possible cytoprotective and reparative effects of teduglutide were analyzed on a mouse model with lung injury induced by tumor necrosis factor-alpha (TNF-α) and actinomycin D (Act D). BALB/c mice were divided into six groups: control mice (I), mice injected intraperitoneally with 15 µg/kg TNF-α (II), 800 µg/kg Act D (III), Act D 2 min prior to TNF-α administration with the same doses (IV), mice injected subcutaneously with 200 µg/kg teduglutide every 12h for 10 consecutive days (V), and mice given Act D 2 min prior to TNF-α administration on day 11 after receiving teduglutide for 10 days (VI). The TNF-α/Act D administration made the lung a sensitive organ to damage. Mice lung subjected to TNF-α/Act D were characterized by the disruption of alveolar wall, induced pulmonary endothelial/epithelial cell apoptosis and expression of active caspase-3. These mice exhibited an increase in lipid peroxidation, glutathione levels, and activities of myeloperoxidase, superoxide dismutase, catalase, glutathione peroxidase and xanthine oxidase, as well as reduced tissue factor and sodium-potassium/ATPase activities. Teduglutide pretreatment regressed the structural damage, cell apoptosis and oxidative stress by reducing lipid peroxidation in mice received TNF-α/Act D. GLP-2 receptors were present on the cell membrane of type II pneumocytes and interstitial cells. Thus, teduglutide can be suggested as a novel protective agent, which possesses anti-apoptotic and anti-oxidant properties, against lung injury.

Neurotrophin-4 dependency of intraepithelial vagal sensory nerve terminals that selectively contact pulmonary NEBs in mice.

Important physiological functions of neurotrophins (NTs) in airways and lungs are the early development, differentiation and maintenance of peripheral sensory neurons. The main pulmonary sensory innervation is of vagal origin, with several nerve fibre populations that selectively contact complex morphologically well-characterized receptor end-organs, called neuroepithelial bodies (NEBs). NEBs in mouse lungs are innervated by at least two separate myelinated vagal sensory nerve fibre populations, of which the neurochemical coding is suggestive of a mechanosensory function. Since neurotrophin-4 (NT-4) has been especially described to be important for the maintenance of mechanosensory nerve terminals, the present study aimed at investigating the NT-4 dependency of the two myelinated vagal sensory nerve fibre populations innervating mouse pulmonary NEBs. Multiple immunostaining in 21-day-old and adult mouse lungs revealed the expression of the NT-4 receptor TrkB on the two different myelinated vagal sensory nerve fibre populations, i.e., the vesicular glutamate transporter/calbindin-positive and the P2X2/3-positive fibres, which selectively contact pulmonary NEBs. Examination of the effect of the lack of NT-4 on these NEB-related nerve fibre populations, by comparing adult NT-4-/- and wild-type mice, revealed that in NT-4-/- mice the percentage of NEBs contacted by P2X2/3+ is reduced by 75%, while the VGLUT+/CB+ population seemed to be unaffected. This study demonstrated that although mouse pulmonary NEBs are contacted by two distinct TrkB expressing populations of vagal myelinated afferents, only one is distinctly reduced in NT-4 deficient mice, suggesting the involvement of NTs. In view of the growing evidence for the involvement of NTs in neuronal plasticity associated with airway diseases, pulmonary NEBs innervated by NT-sensitive vagal afferents may play a significant role.