Lipopolysaccharide preconditioning enhances the efficacy of mesenchymal stem cells transplantation in a rat model of acute myocardial infarction

Background  

Mesenchymal stem cells (MSCs)-based regenerative therapy is currently regarded as an alternative approach to salvage the acute myocardial infarcted hearts. However, the efficiency of MSCs transplantation is limited by lower survival rate of engrafted MSCs. In previous study, we found that 1.0 μg/ml Lipopolysaccharide (LPS) could protect MSCs against apoptosis induced by oxidative stress and meanwhile enhance the proliferation of MSCs. Therefore, in the present study, we firstly preconditioned MSCs with 1.0 μg/ml LPS, then transplanted MSCs into ischemic myocardium, and observed the survival and cardiac protective capacity of MSCs in a rat model of acute myocardial infarction. Furthermore, we tried to explore the underlying mechanisms and the role of Toll-like receptor-4 (TLR4) in the signal pathway of LPS-induced cardiac protection.     

Long-term Exposure to Low Lithium Concentrations Stimulates Proliferation,Modifies Stress Protein Expression Pattern and Enhances Resistance to Oxidative Stress in SH-SY5Y Cells

SH-SY5Y cells, derived from a human neuroblastoma, were submitted to short- or long-term exposures to lithium carbonate concentrations ranging from 0.5 to 8 mM. Short-term exposures (4 days) to concentrations higher than 6 mM were found to reduce cell growth rate while exposure to 8 mM resulted in significant cell mortality. These ranges of concentrations induced an overexpression of (1) the HSP27 stress protein, (2) a 108 kDa protein (P108) recognized by an anti-phospho-HSP27(Ser78) antibody, and probably corresponding to a phosphorylated HSP27 tetramer, (3) a 105 kDa protein (P105), possible glycosylated or phosphorylated form of the GRP94 stress protein and (4) a phosphorylated (inactivated) form of glycogen synthase kinase (GSK3α/β) SH-SY5Y cells, when cultured in the presence of 0.5 mM lithium for 25 weeks, displayed interesting features as compared to controls: (1) higher cell growth rate, (2) increased resistance toward the inhibitory effects of high lithium concentrations on cell proliferation, (3) lower basal level of lipid peroxidation (TBARS) and improved tolerance to oxidative stress induced by high lithium concentrations, (5) reduced expression of monomeric HSP27 versus an increase of corresponding tetrameric protein (P108) and (6) overexpression of a 105 kDa protein (P105). In conclusion, our study suggests that chronic treatment (over several months) by therapeutic relevant lithium concentrations could favour neurogenesis, decrease the vulnerability of neuronal cells to oxidative stress and induce posttranslational changes of molecular chaperones.     

Cytoprotective propensity of Bacopa monniera against hydrogen peroxide induced oxidative damage in neuronal and lung epithelial cells

Hydrogen peroxide (H₂O₂), a major reactive oxygen species (ROS) produced during oxidative stress, is toxic to the cells. Hence, H₂O₂ has been extensively used to study the effects of antioxidant and cytoprotective role of phytochemicals. In the present investigation H₂O₂ was used to induce oxidative stress via ROS production within PC12 and L132 cells. Cytoprotective propensity of Bacopa monniera extract (BME) was confirmed by cell viability assays, ROS estimation, lipid peroxidation, mitochondria membrane potential assay, comet assay followed by gene expression studies of antioxidant enzymes in PC12 and L132 cells treated with H₂O₂ for 24 h with or without BME pre-treatment. Our results elucidate that BME possesses radical scavenging activity by scavenging 2,2-diphenyl-1-picrylhydrazyl, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid), superoxide radical, and nitric oxide radicals. The IC₅₀ value of BME against these radicals was found to be 226.19, 15.17, 30.07, and 34.55 µg/ml, respectively). The IC₅₀ of BME against ROS, lipid peroxidation and protein carbonylation was found to be 1296.53, 753.22, and 589.04 µg/ml in brain and 1137.08, 1079.65, and 11101.25 µg/ml in lung tissues, respectively. Further cytoprotective potency of the BME ameliorated the mitochondrial and plasma membrane damage induced by H₂O₂ as evidenced by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and lactate dehydrogenase leakage assays in both PC12 and L132 cells. H₂O₂ induced cellular, nuclear and mitochondrial membrane damage was restored by BME pre-treatment. H₂O₂ induced depleted antioxidant status was also replenished by BME pre-treatment. This was confirmed by spectrophotometric analysis, semi-quantitative RT-PCR and western blot studies. These results justify the traditional usage of BME based on its promising antioxidant and cytoprotective property.     

Intratracheal mesenchymal stem cell administration attenuates monocrotaline-induced pulmonary hypertension and endothelial dysfunction

The administration of mesenchymal stem cells (MSCs) has been proposed for the treatment of pulmonary hypertension. However, the effect of intratracheally administered MSCs on the pulmonary vascular bed in monocrotaline-treated rats has not been determined. In the present study, the effect of intratracheal administration of rat MSCs (rMSCs) on monocrotaline-induced pulmonary hypertension and impaired endothelium-dependent responses were investigated in the rat. Intravenous injection of monocrotaline increased pulmonary arterial pressure and vascular resistance and decreased pulmonary vascular responses to acetylcholine without altering responses to sodium nitroprusside and without altering systemic responses to the vasodilator agents when responses were evaluated at 5 wk. The intratracheal injection of 3 x 10(6) rMSCs 2 wk after administration of monocrotaline attenuated the rise in pulmonary arterial pressure and pulmonary vascular resistance and restored pulmonary responses to acetylcholine toward values measured in control rats. Treatment with rMSCs decreased the right ventricular hypertrophy induced by monocrotaline. Immunohistochemical studies showed widespread distribution of lacZ-labeled rMSCs in lung parenchyma surrounding airways in monocrotaline-treated rats. Immunofluorescence studies revealed that transplanted rMSCs retained expression of von Willebrand factor and smooth muscle actin markers specific for endothelial and smooth muscle phenotypes. However, immunolabeled cells were not detected in the wall of pulmonary vessels. These data suggest that the decrease in pulmonary vascular resistance and improvement in response to acetylcholine an endothelium-dependent vasodilator in monocrotaline-treated rats may result from a paracrine effect of the transplanted rMSCs in lung parenchyma, which improves vascular endothelial function in the monocrotaline-injured lung.     

Effects of the overexpression of the small heat shock protein,HSP27, on the sensitivity of human fibroblast cells exposed to oxidative stress

The role of the human small heat shock protein (HSP27) in oxidative stress was examined using stable transformants of an immortalized human fibroblast cell line (KMST-6) isolated by transfection of HSP27 expression vectors. Several stable transformants that expressed high or low levels of HSP27 protein were obtained. Clones expressing high levels of HSP27 were more sensitive to growth inhibition by a low dose of hydrogen peroxide (0.1 mM) than those expressing low levels. Clones expressing high levels of HSP27 did not acquire obvious resistance to hyperthermy and cytotoxic agents, except for one (#13), in which resistance to cytotoxic agents was increased. The level of phosphorylated HSP27 in clones expressing high levels of this protein increased at 30 min and was sustained even 4 hours after exposing the cells to 0.1 mM of hydrogen peroxide. On the other hand, the levels in clones expressing low levels of HSP27 were reduced within 4 hours after exposure to hydrogen peroxide. Furthermore, overexpression of nonphosphorylatable mutant HSP27 did not affect sensitivity to oxidative stress. These results suggested that constitutively high expression of HSP27 in KMST-6 cells make them susceptible to oxidative stress resulting in growth arrest, and this mechanism could involve the phosphorylation of HSP27. © 1995 Wiley-Liss, Inc.     

The Heme Oxygenase 1 Inducer (CoPP) Protects Human Cardiac Stem Cells against Apoptosis through Activation of the Extracellular Signal-regulated Kinase (ERK)/NRF2 Signaling Pathway and Cytokine Release

Intracoronary delivery of c-kit-positive human cardiac stem cells (hCSCs) is a promising approach to repair the infarcted heart, but it is severely limited by the poor survival of donor cells. Cobalt protoporphyrin (CoPP), a well known heme oxygenase 1 inducer, has been used to promote endogenous CO generation and protect against ischemia/reperfusion injury. Therefore, we determined whether preconditioning hCSCs with CoPP promotes CSC survival. c-kit-positive, lineage-negative hCSCs were isolated from human heart biopsies. Lactate dehydrogenase release assays demonstrated that preconditioning CSCs with CoPP markedly enhanced cell survival after oxidative stress induced by H₂O₂, concomitant with up-regulation of heme oxygenase 1, COX-2, and anti-apoptotic proteins (BCL2, BCL2-A1, and MCL-1) and increased phosphorylation of NRF2. Apoptotic cytometric assays showed that pretreatment of CSCs with CoPP enhanced the cells'' resistance to apoptosis induced by oxidative stress. Conversely, knocking down HO-1, COX-2, or NRF2 by shRNA gene silencing abrogated the cytoprotective effects of CoPP. Further, preconditioning CSCs with CoPP led to a global increase in release of cytokines, such as EGF, FGFs, colony-stimulating factors, and chemokine ligand. Conditioned medium from cells pretreated with CoPP conferred naive CSCs remarkable resistance to apoptosis, demonstrating that cytokines released by preconditioned cells play a key role in the anti-apoptotic effects of CoPP. Preconditioning CSCs with CoPP also induced an increase in the phosphorylation of Erk1/2, which are known to modulate multiple pro-survival genes. These results potentially provide a simple and effective strategy to enhance survival of CSCs after transplantation and, therefore, their efficacy in repairing infarcted myocardium.     

Passage-restricted differentiation potential of mesenchymal stem cells into cardiomyocyte-like cells

Mesenchymal stem cells (MSCs) have limited ability to differentiate into cardiomyocytes and the factors affect this process are not fully understood. In this study, we investigated the passage (P)-related transdifferentiation potential of MSCs into cardiomyocyte-like cells and its relationship to the proliferation ability. After 5-azacytidine treatment, only P4 but not P1 and P8 rat bone marrow MSCs (rMSCs) showed formation of myotube and expressed cardiomyocyte-associated markers. The growth property analysis showed P4 rMSCs had a growth-arrest appearance, while P1 and P8 rMSCs displayed an exponential growth pattern. When the rapid proliferation of P1 and P8 rMSCs was inhibited by 5-bromo-2-deoxyuridine, a mitosis inhibitor, only P1, not P8 rMSCs, differentiated into cardiomyocyte-like cells after 5-azacytidine treatment. These results demonstrate that the differentiation ability of rMSCs into cardiomyocytes is in proliferation ability-dependent and passage-restricted patterns. These findings reveal a novel regulation on the transdifferentiation of MSCs and provide useful information for exploiting the clinical therapeutic potential of MSCs.     

Trichostatin a modulates intracellular reactive oxygen species through SOD2 and FOXO1 in human bone marrow‐mesenchymal stem cells

Engraft cells are often exposed to oxidative stress and inflammation; therefore, any factor that can provide the stem cells resistance to these stresses may yield better efficacy in stem cell therapy. Studies indicate that histone deacetylase (HDACs) inhibitors alleviate damage induced by oxidative stress. In this study, we investigated whether regulation of reactive oxygen species (ROS) occurs through the HDAC inhibitor trichostatin A (TSA) in human bone marrow‐mesenchymal stem cells (hBM‐MSCs). Intracellular ROS levels increased following exposure to hydrogen peroxide (H₂O₂), and were suppressed by TSA treatment. Levels of the antioxidant enzyme superoxide dismutase 2 (SOD2) increased following treatment with 200 nM TSA and to a lesser level at 1–5 μM TSA. Cell protective effects against oxidative stress were significantly increased in TSA‐MSCs after treatment with low doses of TSA (50–500 nM) and decreased with high doses of TSA (5–10 μM). Consistent results were obtained with immunoblot analysis for caspase3. Investigation of Forkhead box O1 (FOXO1), superoxide dismutase 2 (SOD2), and p53 levels to determine intracellular signaling by TSA in oxidative stress‐induced MSCs demonstrated that expression of phosphorylated‐FOXO1 and phosphorylated‐SOD2 decreased in H₂O₂‐treated MSCs while levels of p53 increased. These effects were reversed by the treatment of 200 nM TSA. These results suggest that the main function of ROS modulation by TSA is activated through SOD2 and FOXO1. Thus, optimal treatment with TSA may protect hBM‐MSCs against oxidative stress. Copyright © 2014 John Wiley & Sons, Ltd.     

氨基修饰的纳米纤维对人和大鼠 MSCs增殖分化的影响

目的:探讨氨基修饰后的静电纺丝纳米纤维对大鼠和人骨髓来源的间充质干细胞(Rat and human bone marrow mesenchymal stem cells, r MSCs and hMSCs)增殖及成骨分化的影响。方法:采用静电纺丝法制备聚乳酸-羟基乙酸共聚物(poly(lactic-co-glycolic acid),PLGA)纳米纤维,用氨气等离子体处理其表面来接枝氨基;通过测量PLGA纳米纤维(NF)及氨基修饰后的纳米纤维(NF-NH_2)接触角来证明修饰效果;将r MSCs和hMSCs分别接种于NF和NF-NH_2,用CCK-8试剂盒检测接种后1, 3 (4), 7天的细胞增殖;接种后的21天,用茜素红S染色(ARS)法检测细胞成骨分化情况。结果:氨气等离子体处理后纳米纤维接触角从81.28±0.33降低至53.99±0.79,说明氨基修饰后的PLGA NF亲水性增加;CCK-8结果显示氨基修饰增加了r MSCs的黏附,接种24 h后r MSCs在NF和NF-NH_2上的检测吸光值分别为0.096±0.011和0.175±0.014(P0.001),而对hMSCs黏附和增殖没有影响,接种24 h后hMSCs在NF和NF-NH_2上的检测吸光值分别为0.237±0.004和0.238±0.006(P0.05);ARS染色结果显示氨基修饰后r MSCs成骨分化增多(在NF和NF-NH_2表面ARS染色区域比例分别13.147±3.223%和36.677±5.230%),而hMSCs在修饰前后的纳米纤维上均有表达(修饰前后ARS染色比例分别为50.283±2.942%和38.254±3.272%)。结论:氨基修饰的NF可以促进大鼠来源的MSCs黏附增殖以及成骨分化,而对人骨髓来源的MSCs没有显著影响,这提示我们MSCs的增殖分化行为可能具有种属依赖性。     

Spontaneous expression of neural phenotype and NGF, TrkA, TrkB genes in marrow stromal cells

Marrow stromal cells (MSCs) have the ability to provide growth factors and differentiate into neural-like cells on treating with EGF, bFGF and other factors. We wanted to explore whether growth factors secreted by MSCs itself could induce self-differentiation into neural-like cells. Here, we show that even in the absence of inducing factors, rMSCs spontaneously differentiate into neural-like cells expressing neural markers, such as nestin, beta-tubulin III, Doublecortin (DCX), microtubule-associated protein 2 (MAP2) and neuron-specific enolase (NSE). Furthermore, some cells become neurosphere-like growing in suspension. Compared with control and neural-like rMSCs induced by epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF), we found using real-time PCR that self-differentiating rMSCs (SDrMSCs) expressed significantly higher levels of neurotrophic high-affinity receptors (TrkA and TrkB). Coincident with neural marker expression, nerve growth factor (NGF) mRNA was significantly higher than controls despite lower protein levels in the supernatant. Our study suggests that rMSCs have the potential to differentiate into neural cells spontaneously in culture and may contribute towards the natural function of MSCs for neural system in vivo.     

Adaptation of the Phytopathogenic Fungus Fusarium decemcellulare to Oxidative Stress

The adaptive response of the phytopathogenic fungus Fusarium decemcellulare to the oxidative stress induced by hydrogen peroxide and juglone (5-hydroxy-1,4-naphthoquinone) was studied. At concentrations higher than 1 mM, H₂O₂ and juglone completely inhibited the growth of the fungus. The 60-min pretreatment of logarithmic-phase cells with nonlethal concentrations of H₂O₂ (0.25 mM) and juglone (0.1 mM) led to the development of a resistance to high concentrations of these oxidants. The stationary-phase cells were found to be more resistant to the oxidants than the logarithmic-phase cells. The adaptation of fungal cells to H₂O₂ and juglone was associated with an increase in the activity of cellular catalase and superoxide dismutase, the main enzymes involved in the defense against oxidative stress.     

Switching off HSP70 and i-NOS to study their role in normal and H2O2-stressed human fibroblasts

i-NOS and HSP70 antisense oligonucleotides were used to study the role of the two well known stress-regulated molecules on cell survival of both untreated control, and H2O2-stressed human fibroblasts. Cell survival was assessed either by LDH release or by MTT assay. The levels of cytosolic i-NOS and HSP70 were tested by using immunoblotting analysis, and reactive oxygen species (ROS) production was quantified. Compared to the values observed in untreated control cells, anti HSP70-transfected human fibroblasts showed an increase in ROS production, i-NOS level and LDH release. The addition of 0.12 mM H2O2 for 20 min. to the HSP70-deprived fibroblasts did not modify the percentage of LDH release observed in H2O2 stressed cells, but reduced cell viability increasing both ROS production and i-NOS level. Anti i-NOS-transfected fibroblasts, compared to the control untreated cells, showed no modification in ROS production, while cell survival was improved. When treated with H2O2 the i-NOS depleted cells counteracted ROS formation as well as LDH release but negatively affected cell viability and HSP70 levels, compared to the results obtained with H2O2 alone-treated fibroblasts. The data indicates that the induced decrease in HSP70 level in oxidative stress conditions makes fibroblasts more prone to oxidative injury and also increases i-NOS level. Whereas in one way the forced decrease in i-NOS expression seems to counteract ROS production stimulated by the oxidative insult in the cells, in another way, since it causes a decrease in HSP70 expression as well as in cell viability, it seems to activate some unidentified pathways affecting cell demise.     

The time-profile of the PBMC HSP70 response to in vitro heat shock appears temperature-dependent

Summary. Heat shock proteins (HSPs) are synthesised by cells subsequent to a stress exposure and are known to confer protection to the cell in response to a second challenge. HSP induction and decay are correlated to thermotolerance and may therefore be used as a biomarker of thermal history. The current study tested the temperature-dependent nature of the heat shock response and characterised its time profile of induction. Whole blood from 6 healthy males (Age: 26 ± (SD) 2 yrs; Body mass 74.2 ± 3.8 kgs; VO_2max: 49.1 ± 4.0 ml·kg⁻¹·min⁻¹) were isolated and exposed to in vitro heat shock (HS) at 37, 38, 39, 40, and 41 °C for a period of 90 min. After HS the temperature was returned to 37 °C and intracellular HSP70 was quantified from the leukocytes at 0, 2, 4, and 6 h after heat treatment. The concentration of HSP70 was not different between temperatures (P > 0.05), but the time-profile of HSP70 synthesis appeared temperature-dependent. At control (37 °C) and lower temperatures (38–39 °C) the mean HSP70 concentration increased up to 4 h post HS (P < 0.05) and then returned towards baseline values by 6 h post HS. With in vitro hyperthermic conditions (40–41 °C), the time-profile was characterised by a sharp rise in HSP70 levels immediately after treatment (P < 0.05 for 40 °C at 0 h), followed by a progressive decline over time. The results suggest a temperature-dependent time-profile of HSP70 synthesis. In addition, the temperature at which HSP70 is inducted might be lower than 37 °C.     

Heat-shock protein 72 cell-surface expression on human lung carcinoma cells is associated with an increased sensitivity to lysis mediated by adherent natural killer cells

 The cell-surface expression patterns of major histocompatibility complex (MHC) class I, class II and heat-shock protein 72 (HSP72) molecules were measured on human lung (LX-1) and mammary (MX-1) carcinoma cells. No major differences were found in the MHC cell-surface expression pattern of both cell lines. However, they differ significantly in their capacity to express HSP72 on their cell surface. Under physiological conditions LX-1 cells express HSP72 molecules on more than 90% of the cells, whereas MX-1 cells exhibit no significant HSP72 cell-surface expression (less than 5%). These expression patterns remained stable in all further cell passages tested. The sensitivity to lysis mediated by an interleukin-2 (IL-2)-stimulated, adherent natural killer (NK) cell population could be correlated with the amount of cell-surface-expressed HSP72 molecules. By antibody-blocking studies, using HSP72-specific monoclonal antibody (mAb), a strong inhibition of lysis was only found with LX-1 cells but not with MX-1 cells. In contrast to the cell-surface expression, the cytoplasmic amount of HSP72 in MX-1 cells was twice as high compared to LX-1 cells under physiological conditions. After nonlethal heat-shock the rate of induction and the total cytoplasmic amounts of HSP72 were comparable in both cell lines. The clonogenic cell viability of LX-1 cells after incubation at temperatures ranging from 41°C to 44°C was significantly elevated compared to that of MX-1 cells. In conclusion we state the following: (i) HSP72 cell-surface expression on human carcinoma cells is independent of the cytoplasmic amount of HSP72; (ii) the cell-surface expression of HSP72 is associated with an increased sensitivity of tumour cells to lysis mediated by an IL-2-stimulated, adherent NK cell population; (iii) thermoresistance is not related to the cytoplasmic HSP72 level but might be related to the amount of HSP72 expressed on the cell surface. Received: 20 June 1996 / Accepted: 25 September 1996     

Preinduction of HSP70 promotes hypoxic tolerance and facilitates acclimatization to acute hypobaric hypoxia in mouse brain

It has been shown that induction of HSP70 by administration of geranylgeranylacetone (GGA) leads to protection against ischemia/reperfusion injury. The present study was performed to determine the effect of GGA on the survival of mice and on brain damage under acute hypobaric hypoxia. The data showed that the mice injected with GGA survived significantly longer than control animals (survival time of 9.55 ± 3.12 min, n = 16 vs. controls at 4.28 ± 4.29 min, n = 15, P < 0.005). Accordingly, the cellular necrosis or degeneration of the hippocampus and the cortex induced by sublethal hypoxia for 6 h could be attenuated by preinjection with GGA, especially in the CA2 and CA3 regions of the hippocampus. In addition, the activity of nitric oxide synthase (NOS) of the hippocampus and the cortex was increased after exposure to sublethal hypoxia for 6 h but could be inhibited by the preinjection of GGA. Furthermore, the expression of HSP70 was significantly increased at 1 h after GGA injection. These results suggest that administration of GGA improved survival rate and prevented acute hypoxic damage to the brain and that the underlying mechanism involved induction of HSP70 and inhibition of NOS activity.     

Hypoxic preconditioning advances CXCR4 and CXCR7 expression by activating HIF-1α in MSCs

Recent evidence indicated that sublethal hypoxic preconditioning (HP) of bone marrow-derived mesenchymal stem cells (MSCs) before transplantation could ameliorate their capacity to survive and engraft in the target tissue through yet undefined mechanisms. In this study, we demonstrated that HP (3% oxygen) induced the high expression of both chemokine stromal-derived factor-1 (SDF-1) receptors, CXCR4 and CXCR7, in MSCs. HP also improved in vitro migration, adhesion and survival of MSCs. Although SDF-1-induced migration of HP-MSCs was only abolished by an anti-CXCR4 antibody, both CXCR4 and CXCR7 were responsible for elevated adhesion of HP-MSCs. Moreover, CXCR7 but not CXCR4 was essential for the resistance to oxidative stress of HP-MSC. In addition, HP also evoked an increase in expression of hypoxia-inducible factor-1 (HIF-1α) and phosphorylation of Akt. The chemical inducers of HIF-1α, desferrioxamine (DFX) and cobalt chloride (CoCl₂), induced upregulation of CXCR4 and CXCR7 expression in MSCs under normoxic conditions. Contrarily, blockade of HIF-1α by siRNA and inhibition of Akt by either wortmannin or LY294002 abrogated upregulation of HP-induced CXCR4 and CXCR7 in MSCs. Collectively, these findings provide evidence for a crucial role of PI3K/Akt-HIF-1α-CXCR4/CXCR7 pathway on enhanced migration, adhesion and survival of HP-MSCs in vitro.     

The role of oxidative stress in rhinovirus induced elaboration of IL-8 by respiratory epithelial cells

A direct correlation has been reported between the severity of symptoms associated with rhinovirus infection and the concentration of interleukin-8 in nasal secretions. The purpose of these studies was to examine the mechanism of rhinovirus-induced IL-8 elaboration. Rhinovirus infection induced oxidative stress in Beas-2b cells and the concentration of H₂O₂ in supernatant media from rhinovirus challenged cells was 12.5 ± 6.1 μM 1 h after challenge compared to 0.7 ± 0.3 μM in supernatant from control cells. N-acetyl cysteine inhibited RV-induced NF-κB activation and IL-8 elaboration. IL-8 concentrations were 36 ± 2 pg/ml and 10 ± 1 pg/ml 6 h after virus challenge in untreated and NAC-treated (30 mM NAC) cells, respectively. Despite the effects of NAC on IL-8 elaboration and NF-κB activation, RV stimulated increases in supernatant H₂O₂ were not altered by NAC. These data suggest that RV stimulation of IL-8 in respiratory epithelium is mediated through production of oxidative species and the subsequent activation of NF-κB.     

Mesenchymal stem cells protect cigarette smoke‐damaged lung and pulmonary function partly via VEGF–VEGF receptors

Progressive pulmonary inflammation and emphysema have been implicated in the progression of chronic obstructive pulmonary disease (COPD), while current pharmacological treatments are not effective. Transplantation of bone marrow mesenchymal stem cells (MSCs) has been identified as one such possible strategy for treatment of lung diseases including acute lung injury (ALI) and pulmonary fibrosis. However, their role in COPD still requires further investigation. The aim of this study is to test the effect of administration of rat MSCs (rMSCs) on emphysema and pulmonary function. To accomplish this study, the rats were exposed to cigarette smoke (CS) for 11 weeks, followed by administration of rMSCs into the lungs. Here we show that rMSCs infusion mediates a down‐regulation of pro‐inflammatory mediators (TNF‐α, IL‐1β, MCP‐1, and IL‐6) and proteases (MMP9 and MMP12) in lung, an up‐regulation of vascular endothelial growth factor (VEGF), VEGF receptor 2, and transforming growth factor (TGFβ‐1), while reducing pulmonary cell apoptosis. More importantly, rMSCs administration improves emphysema and destructive pulmonary function induced by CS exposure. In vitro co‐culture system study of human umbilical endothelial vein cells (EA.hy926) and human MSCs (hMSCs) provides the evidence that hMSCs mediates an anti‐apoptosis effect, which partly depends on an up‐regulation of VEGF. These findings suggest that MSCs have a therapeutic potential in emphysematous rats by suppressing the inflammatory response, excessive protease expression, and cell apoptosis, as well as up‐regulating VEGF, VEGF receptor 2, and TGFβ‐1. J. Cell. Biochem. 114: 323–335, 2013. © 2012 Wiley Periodicals, Inc.