Mesenchymal stem cells from different sources show distinct therapeutic effects in hyperoxia-induced bronchopulmonary dysplasia in rats

Mesenchymal stem cells (MSCs) have been shown as an effective medicinal means to treat bronchopulmonary dysplasia (BPD). The widely used MSCs were from Wharton's jelly of umbilical cord (UC-MSCs) and bone marrow (BM-MSCs). Amniotic fluid MSCs (AF-MSCs) may be produced before an individual is born to treat foetal diseases by autoplastic transplantation. We evaluated intratracheal (IT) MSCs as an approach to treat an hyperoxia-induced BPD animal model and compared the therapeutic effects between AF-, UC- and BM-MSCs. A BPD animal model was generated by exposing newborn rats to 95% O₂. The continued stress lasted 21 days, and the treatment of IT MSCs was conducted for 4 days. The therapeutic effects were analysed, including lung histology, level of inflammatory cytokines, cell death ratio and state of angiogenesis, by sacrificing the experimental animal at day 21. The lasting hyperoxia stress induced BPD similar to the biological phenotype. The treatment of IT MSCs was safe without deaths and normal organ histopathology. Specifically, the treatment was effective by inhibiting the alveolar dilatation, reducing inflammatory cytokines, inducing angiogenesis and lowering the cell death ratio. AF-MSCs had better therapeutic effects compared with UC-MSCs in relieving the pulmonary alveoli histological changes and promoting neovascularization, and UC-MSCs had the best immunosuppressive effect in plasma and lung lysis compared with AF-MSCs and BM-MSCs. This study demonstrated the therapeutic effects of AF-, UC- and BM-MSCs in BPD model. Superior treatment effect was provided by antenatal MSCs compared to BM-MSC in a statistical comparison.     

Vascular mediators in chronic lung disease of infancy: Role of endothelial monocyte activating polypeptide II (EMAP II)

Bronchopulmonary dysplasia (BPD) is a chronic lung disease of prematurity. Over the years, the BPD phenotype has evolved, but despite various advances in neonatal management approaches, the reduction in the BPD burden is minimal. With the advent of surfactant, glucocorticoids, and new ventilation strategies, BPD has evolved from a disease of structural injury into a new BPD, marked by an arrest in alveolar growth in the lungs of extremely premature infants. This deficient alveolar growth has been associated with a diminution of pulmonary vasculature. Several investigators have described the epithelial / vascular co‐dependency and the significant role of crosstalk between vessel formation, alveologenesis, and lung dysplasia's; hence identification and study of factors that regulate pulmonary vascular emergence and inflammation has become crucial in devising effective therapeutic approaches for this debilitating condition. The potent antiangiogenic and proinflammatory protein Endothelial Monocyte Activating Polypeptide II (EMAP II) has been described as a mediator of pulmonary vascular and alveolar formation and its expression is inversely related to the periods of vascularization and alveolarization in the developing lung. Hence the study of EMAP II could play a vital role in studying and devising appropriate therapeutics for diseases of aberrant lung development, such as BPD. Herein, we review the vascular contribution to lung development and the implications that vascular mediators such as EMAP II have in distal lung formation during the vulnerable stage of alveolar genesis. Birth Defects Research (Part A) 100:180–188, 2014. © 2014 Wiley Periodicals, Inc.     

Umbilical cord-derived mesenchymal stem cells alleviated inflammation and inhibited apoptosis in interstitial cystitis via AKT/mTOR signaling pathway

Interstitial cystitis (IC) is a bladder syndrome characterized by pelvic pain and urinary frequency without infection or other identifiable pathology. There are no effective treatments to cure IC. This study investigated the effects of human umbilical cord-derived mesenchymal stem cells (UC-MSCs) injection on IC rat model. Furthermore, we used a coculture system to find the possible molecular mechanism on the human uroepithelial cells (SV-HUC-1), which was the cell model of IC. A rat model of IC was established via systemic injection with cyclophosphamide (CYP) and a cell model of IC was induced by being exposed to tumor necrosis factor (TNF)-α (10 ng/ml). After one week, UC-MSCs injection significantly ameliorated the bladder voiding function in IC rat model. And the Histo- and immunohistochemical analyses showed that UC-MSCs can repair impaired bladder, reduce mast cell infiltration and inhibit apoptosis of urothelium. ELISA results showed that UC-MSCs can decrease IL-1β, IL-6 and TNF-α in bladder. In the coculture system, UC-MSCs can promote proliferation of impaired SV-HUC-1 cells, and inhibit apoptosis. However, while knocked down EGF secreted by UC-MSCs with siRNA, the effects would be weaken. Western blot showed that UC-MSCs increase protein expression levels of p-AKT and p-mTOR in SV-HUC-1 cells, and decrease the levels of cleaved caspase-3. Taken together, we provide evidence that UC-MSCs therapy can successfully alleviate IC in a preclinical animal Model and cell model by alleviating inflammation, promoting proliferation and inhibiting apoptosis. In addition, we demonstrate that the AKT/mTOR signaling pathway was activated.     

The Axonal Guidance Cue Semaphorin 3C Contributes to Alveolar Growth and Repair

Lung diseases characterized by alveolar damage such as bronchopulmonary dysplasia (BPD) in premature infants and emphysema lack efficient treatments. Understanding the mechanisms contributing to normal and impaired alveolar growth and repair may identify new therapeutic targets for these lung diseases. Axonal guidance cues are molecules that guide the outgrowth of axons. Amongst these axonal guidance cues, members of the Semaphorin family, in particular Semaphorin 3C (Sema3C), contribute to early lung branching morphogenesis. The role of Sema3C during alveolar growth and repair is unknown. We hypothesized that Sema3C promotes alveolar development and repair. In vivo Sema3C knock down using intranasal siRNA during the postnatal stage of alveolar development in rats caused significant air space enlargement reminiscent of BPD. Sema3C knock down was associated with increased TLR3 expression and lung inflammatory cells influx. In a model of O₂-induced arrested alveolar growth in newborn rats mimicking BPD, air space enlargement was associated with decreased lung Sema3C mRNA expression. In vitro, Sema3C treatment preserved alveolar epithelial cell viability in hyperoxia and accelerated alveolar epithelial cell wound healing. Sema3C preserved lung microvascular endothelial cell vascular network formation in vitro under hyperoxic conditions. In vivo, Sema3C treatment of hyperoxic rats decreased lung neutrophil influx and preserved alveolar and lung vascular growth. Sema3C also preserved lung plexinA2 and Sema3C expression, alveolar epithelial cell proliferation and decreased lung apoptosis. In conclusion, the axonal guidance cue Sema3C promotes normal alveolar growth and may be worthwhile further investigating as a potential therapeutic target for lung repair.     

Phosphodiesterase 4 inhibition attenuates persistent heart and lung injury by neonatal hyperoxia in rats

Phosphodiesterase (PDE) 4 inhibitors are potent anti-inflammatory drugs with antihypertensive properties, and their therapeutic role in bronchopulmonary dysplasia (BPD) is still controversial. We studied the role of PDE4 inhibition with piclamilast on normal lung development and its therapeutic value on pulmonary hypertension (PH) and right ventricular hypertrophy (RVH) in neonatal rats with hyperoxia-induced lung injury, a valuable model for premature infants with severe BPD. The cardiopulmonary effects of piclamilast treatment (5 mg·kg(-1)·day(-1)) were investigated in two models of experimental BPD: 1) daily treatment during continuous exposure to hyperoxia for 10 days; and 2) late treatment and injury-recovery in which pups were exposed to hyperoxia or room air for 9 days, followed by 9 or 42 days of recovery in room air combined with treatment started on day 6 of oxygen exposure until day 18. Prophylactic piclamilast treatment reduced pulmonary fibrin deposition, septum thickness, arteriolar wall thickness, arteriolar vascular smooth muscle cell proliferation and RVH, and prolonged survival. In the late treatment and injury-recovery model, hyperoxia caused persistent aberrant alveolar and vascular development, PH, and RVH. Treatment with piclamilast in both models reduced arteriolar wall thickness, attenuated RVH, and improved right ventricular function in the injury recovery model, but did not restore alveolarization or angiogenesis. Treatment with piclamilast did not show adverse cardiopulmonary effects in room air controls in both models. In conclusion, PDE4 inhibition attenuated and partially reversed PH and RVH, but did not advance alveolar development in neonatal rats with hyperoxic lung injury or affect normal lung and heart development.     

Extracellular matrix proteins: A positive feedback loop in lung fibrosis?

Lung fibrosis is characterized by excessive deposition of extracellular matrix. This not only affects tissue architecture and function, but it also influences fibroblast behavior and thus disease progression. Here we describe the expression of elastin, type V collagen and tenascin C during the development of bleomycin-induced lung fibrosis. We further report in vitro experiments clarifying both the effect of myofibroblast differentiation on this expression and the effect of extracellular elastin on myofibroblast differentiation.Lung fibrosis was induced in female C57Bl/6 mice by bleomycin instillation. Animals were sacrificed at zero to five weeks after fibrosis induction. Collagen synthesized during the week prior to sacrifice was labeled with deuterium. After sacrifice, lung tissue was collected for determination of new collagen formation, microarray analysis, and histology. Human lung fibroblasts were grown on tissue culture plastic or BioFlex culture plates coated with type I collagen or elastin, and stimulated to undergo myofibroblast differentiation by 0–10 ng/ml transforming growth factor (TGF)β₁. mRNA expression was analyzed by quantitative real-time PCR.New collagen formation during bleomycin-induced fibrosis was highly correlated to gene expression of elastin, type V collagen and tenascin C. At the protein level, elastin, type V collagen and tenascin C were highly expressed in fibrotic areas as seen in histological sections of the lung. Type V collagen and tenascin C were transiently increased. Human lung fibroblasts stimulated with TGFβ₁ strongly increased gene expression of elastin, type V collagen and tenascin C. The extracellular presence of elastin increased gene expression of the myofibroblastic markers α smooth muscle actin and type I collagen.The extracellular matrix composition changes dramatically during the development of lung fibrosis. The increased levels of elastin, type V collagen and tenascin C are probably the result of increased expression by fibroblastic cells; reversely, elastin influences myofibroblast differentiation. This suggests a reciprocal interaction between fibroblasts and the extracellular matrix composition that could enhance the development of lung fibrosis.     

Recombinant human elafin promotes alveologenesis in newborn mice exposed to chronic hyperoxia

Background/aimsElastase inhibitors reverse elastin degradation and abnormal alveologenesis and attenuate the lung structural abnormalities induced by mechanical ventilation with O₂-rich gas. The potential of these molecules to improve endothelial function and to ameliorate severe bronchopulmonary dysplasia (BPD) during lung development is not yet understood. We sought to determine whether the intratracheal treatment of newborn mice with the elastase inhibitor elafin would prevent hyperoxia-induced lung elastin degradation and the cascade of events that cause abnormal alveologenesis.MethodsNewborn mice were exposed to 85% O₂ for 3, 7, 14 or 21 days. Recombinant human elafin was administered by intratracheal instillation from the first day every two days for 20 days. We next used morphometric analyses, quantitative RT-PCR, immunostaining, Western blotting, and ELISA methods to assess the key variables involved in elastogenesis disruption and the potential signaling pathways noted below in recombinant human elafin-treated mouse pups that had been exposed to 85% O₂.ResultsWe found that impaired alveolar development and aberrant elastin production were associated with elevations in whole lung elastase levels in 85% O₂-exposed lungs. Elafin attenuated the structural disintegration that developed in the hyperoxia-damaged lungs. Furthermore, elafin prevented the elastin degradation, neutrophil influx, activation of TGF-β1 and apoptosis caused by 85% O₂ exposure.ConclusionsPulmonary elastase plays an important role in disrupting elastogenesis during O₂-induced damage, which is the result of a pulmonary inflammatory response. Elafin prevents these changes by inhibiting elastase and the TGF-β1 signalling cascade and may be a new therapeutic target for preventing O₂-induced lung injury in neonates.     

Role of bone marrow-derived mesenchymal stem cells in the prevention of hyperoxia-induced lung injury in newborn mice

BPD (bronchopulmonary dysplasia) is predominantly characterized by persistent abnormalities in lung structure and arrested lung development, but therapy can be palliative. While promising, the use of BMSC (bone marrow-derived mesenchymal stem cell) in the treatment of lung diseases remains controversial. We have assessed the therapeutic effects of BMSC in vitro and in vivo. In vitro co-culturing with injured lung tissue increased the migration-potential of BMSC; and SP-C (surfactant protein-C), a specific marker of AEC2 (type II alveolar epithelial cells), was expressed. Following intraperitoneal injection of BMSC into experimental BPD mice on post-natal day 7, it was found that BMSC can home to the injured lung, express SP-C, improve pulmonary architecture, attenuate pulmonary fibrosis and increase the survival rate of BPD mice. This work supports the notion that BMSC are of therapeutic benefit through the production of soluble factors at bioactive levels that regulate the pathogenesis of inflammation and fibrosis following hyperoxia.     

实验性腹膜炎肺损伤时大黄的保护作用

目的探讨大黄对实验性腹膜炎时肺损伤的保护作用.方法用酵母多糖A腹腔注射制备大鼠急性腹膜炎模型,诱发肺脏损伤.将SD大鼠随机分为4组:(1)正常组,(2)模型组,(3)大黄实验组,(4)抗生素实验组(氨苄西林组).测定肺组织匀浆中丙二醛(MDA)、黄嘌呤氧化酶(XOD)、谷光甘肽(GSH)和血清内毒素水平,并进行血气分析及外周血WBC计数.结果大黄组内毒素、肺组织匀浆中MDA和XOD,以及白细胞计数均明显低于模型组(P＜0.05),而还原GSH变化不明显.结论大黄可能通过降低外周及门静脉血内毒素水平,抑制脂质过氧化和加强自由基的清除,从而减轻实验性腹膜炎引起的肺损伤.     

Retinoic acid attenuates O2-induced inhibition of lung septation

Exposure of the newborn lung to hyperoxia is associated with impaired alveolar development. In newborn rats exposed to hyperoxia and studied at day 14 of life, retinoic acid (RA) treatment improved survival and increased lung collagen but did not improve alveolar development. To determine whether RA treatment during exposure to hyperoxia results in late improvement in alveolarization, we treated newborn rats with RA and hyperoxia from day 3 to day 14 and then weaned O2 to room air by day 20, and studied the animals on day 42. O2-exposed animals had larger mean lung volumes, larger alveoli, and decreased gas-exchange tissue relative to air-exposed animals, whereas RA-treated O2-exposed animals were not statistically different from air-exposed controls. Relative to control animals, elastin staining at day 14 was decreased in hyperoxia-exposed lung independent of RA treatment, and, at day 42, elastin staining was similar in all treatment groups. At day 14, elastin gene expression was similar in all treatment groups, whereas at day 42 lung previously exposed to hyperoxia showed increased elastin signal independent of RA treatment. These results indicate that RA treatment during hyperoxia exposure promotes septal formation without evidence of effects on elastin gene expression after 4 wk of recovery.     

Cyclooxygenase-2 in newborn hyperoxic lung injury

Supraphysiological O₂ concentrations, mechanical ventilation, and inflammation significantly contribute to the development of bronchopulmonary dysplasia (BPD).Exposure of newborn mice to hyperoxia causes inflammation and impaired alveolarization similar to that seen in infants with BPD.Previously, we demonstrated that pulmonary cyclooxygenase-2 (COX-2) protein expression is increased in hyperoxia-exposed newborn mice.The present studies were designed to define the role of COX-2 in newborn hyperoxic lung injury.We tested the hypothesis that attenuation of COX-2 activity would reduce hyperoxia-induced inflammation and improve alveolarization.Newborn C3H/HeN micewere injected daily with vehicle, aspirin (nonselective COX-2 inhibitor), or celecoxib (selective COX-2 inhibitor) for the first 7 days of life.Additional studies utilized wild-type (C57Bl/6, COX-2^+/+), heterozygous (COX-2^+/-), and homozygous (COX-2^-/-) transgenic mice.Micewere exposed to room air (21% O₂) or hyperoxia (85% O₂) for 14 days.Aspirin-injected and COX-2^-/- pups had reduced levels of monocyte chemoattractant protein (MCP-1) in bronchoalveolar lavage fluid (BAL).Both aspirin and celecoxib treatment reduced macrophage numbers in the alveolar walls and air spaces.Aspirin and celecoxib treatment attenuated hyperoxia-induced COX activity, including altered levels of prostaglandin (PG)D₂ metabolites.Decreased COX activity, however, did not prevent hyperoxia-induced lung developmental deficits.Our data suggest thatincreased COX-2 activity may contribute to proinflammatory responses, including macrophage chemotaxis, during exposure to hyperoxia.Modulation of COX-2 activity may be a useful therapeutic target to limit hyperoxia-induced inflammation in preterm infants at risk of developing BPD.     

MiR-20a-containing exosomes from umbilical cord mesenchymal stem cells alleviates liver ischemia/reperfusion injury

Mesenchymal stem cells (MSCs) have been proved to exert considerable therapeutic effects on ischemia-reperfusion (I/R)-induced injury, but the underlying mechanism remains unknown. In this study, we aimed to explore the potential molecular mechanism underlying the therapeutic effect of MSCs-derived exosome reinforced with miR-20a in reversing liver I/R injury. Quantitative real-time polymerase chain reaction, Western blot, and IHC were carried out to compare the differential expressions of miR-20a, Beclin-I, FAS, Caspase-3, mTOR and P62 in IR rats and normal rats. TUNEL was performed to assess IR-induced apoptosis in IR rats, and luciferase assay was used to confirm the inhibitory effect of miR-20a on Beclin-I and FAS expression. Among the 12 candidate microRNAs (miRNAs), miR-486, miR-25, miR-24, miR-20a,miR-466 and miR-433-3p were significantly downregulated in I/R. In particular, miR-20a, a miRNA highly expressed in umbilical cord-derived mesenchymal stem cells, was proved to bind to the 3ʹ UTR of Beclin-I and FAS to exert an inhibitory effect on their expressions. Since Beclin-I and FAS were aberrantly upregulated in IR, exosomes separated from UC-MSCs showed therapeutic efficacy in reversing I/R induced apoptosis. In addition, exosomes reinforced with miR-20a and separated from UC-MSCs almost fully alleviated I/R injury. Furthermore, our results showed that miR-20a could alleviate the abnormal expression of genes related to apoptosis and autophagy, such as active Caspase-3, mTOR, P62, and LC3II. This study presented detailed evidence to clarify the mechanism underlying the therapeutic efficacy of UC-MSCs in the treatment of I/R injury.     

Surfactant metabolism and anti-oxidative capacity in hyperoxic neonatal rat lungs: effects of keratinocyte growth factor on gene expression in vivo

Development of preterm infant lungs is frequently impaired resulting in bronchopulmoary dysplasia (BPD). BPD results from interruption of physiologic anabolic intrauterine conditions, the inflammatory basis and therapeutic consequences of premature delivery, including increased oxygen supply for air breathing. The latter requires surfactant, produced by alveolar type II (AT II) cells to lower surface tension at the pulmonary air:liquid interface. Its main components are specific phosphatidylcholine (PC) species including dipalmitoyl-PC, anionic phospholipids and surfactant proteins. Local antioxidative enzymes are essential to cope with the pro-inflammatory side effects of normal alveolar oxygen pressures. However, respiratory insufficiency frequently requires increased oxygen supply. To cope with the injurious effects of hyperoxia to epithelia, recombinant human keratinocyte growth factor (rhKGF) was proposed as a surfactant stimulating, non-catabolic and epithelial-protective therapeutic. The aim of the present study was to examine the qualification of rhKGF to improve expression parameters of lung maturity in newborn rats under hyperoxic conditions (85 % O₂ for 7 days). In response to rhKGF proliferating cell nuclear antigen mRNA, as a feature of stimulated proliferation, was elevated. Similarly, the expressions of ATP-binding cassette protein A3 gene, a differentiation marker of AT II cells and of peroxiredoxin 6, thioredoxin and thioredoxin reductase, three genes involved in oxygen radical protection were increased. Furthermore, mRNA levels of acyl-coA:lysophosphatidylcholine acyltransferase 1, catalyzing dipalmitoyl-PC synthesis by acyl remodeling, and adipose triglyceride lipase, considered as responsible for fatty acid supply for surfactant PC synthesis, were elevated. These results, together with a considerable body of other confirmative evidence, suggest that rhKGF should be developed into a therapeutic option to treat preterm infants at risk for impaired lung development.     

Effect of D-penicillamine on rat lung elastin cross-linking during the perinatal period

This study was designed to clarify the effects of D-penicillamine (DPA), a drug used for treatment of various pathological events, on lung elastin formation and maturation of the newborn in the perinatal period. The investigation was conducted on 20 newborn rats bred from 40 female and six male rats. DPA doses 400 mg kg(-1) day(-1) and physiological saline were given intraperitoneally (i.p) to experimental and control groups. To assess newborn maturation, their body and lung weights were determined. Serum Cu levels were measured by atomic absorption spectroscopy and ceruloplasmin (Cp) activities were measured spectrophotometrically. Newborn lung tissue elastin, desmosine (DES) and isodesmosine (IDES) levels were measured by HPLC. The results showed that DPA treatment caused loss of skin elasticity and reduction in body and lung weight in newborns of the experimental group. The serum Cu levels and Cp activity were found to be significantly lower in both maternal and newborn of the experimental groups compared with the control group. The lung DES, IDES and elastin values of newborns in the experimental group were decreased compared with the control group. In conclusion, our results indicate that 400 mg kg(-1) day(-1) DPA, a dose that is used in the treatment of Wilson's disease, rheumatoid arthritis and cystinuria, caused the retardation of newborn maturation, a decrease in DES-IDES cross-links and levels of lung elastin of offspring in the perinatal period. Another conclusion to be drawn from this study is that even low levels of Cu depletion due to DPA administration induces a change in cross-linking in lung elastin during the perinatal period.     

Epidermal growth factor-like domain 7 protects endothelial cells from hyperoxia-induced cell death

Hyperoxia is one of the major contributors to the development of bronchopulmonary dysplasia (BPD), a chronic lung disease in premature infants. Emerging evidence suggests that the arrested lung development of BPD is associated with pulmonary endothelial cell death and vascular dysfunction resulting from hyperoxia-induced lung injury. A better understanding of the mechanism of hyperoxia-induced endothelial cell death will provide critical information for the pathogenesis and therapeutic development of BPD. Epidermal growth factor-like domain 7 (EGFL7) is a protein secreted from endothelial cells. It plays an important role in vascular tubulogenesis. In the present study, we found that Egfl7 gene expression was significantly decreased in the neonatal rat lungs after hyperoxic exposure. The Egfl7 expression was returned to near normal level 2 wk after discounting oxygen exposure during recovery period. In cultured human endothelial cells, hyperoxia also significantly reduced Egfl7 expression. These observations suggest that diminished levels of Egfl7 expression might be associated with hyperoxia-induced endothelial cell death and lung injury. When we overexpressed human Egfl7 (hEgfl7) in EA.hy926 human endothelial cell line, we found that hEgfl7 overexpression could partially block cytochrome c release from mitochondria and decrease caspase-3 activation. Further Western blotting analyses showed that hEgfl7 overexpression could reduce expression of a proapoptotic protein, Bax, and increase expression of an antiapoptotic protein, Bcl-xL. Theses findings indicate that hEGFL7 may protect endothelial cell from hyperoxia-induced apoptosis by inhibition of mitochondria-dependent apoptosis pathway.     

Sumoylation of CCAAT‐enhancer‐binding protein α inhibits lung differentiation in Bronchopulmonary Dysplasia model rats

Bronchopulmonary dysplasia (BPD) is a major cause of mortality and morbidity in premature infants, characterized by alveolar simplification, surfactant deficiency, and respiratory distress. In the present study, we have investigated the functional roles of sumoylated CCAAT/enhancer binding protein alpha (C/EBPα) in the BPD rat model. A significant increase in small ubiquitin‐like modifier 1 (SUMO1) and sumoylated C/EBPα protein levels were observed in BPD rats, and the levels of the sumoylated C/EBPα were associated with the pulmonary surfactant proteins (SPs). In order to confirm the role of sumoylated C/EBPα in BPD rats, SUMO1 was knocked down by lentiviral transfection of neonatal rat lungs with SUMO1‐RNAi‐LV. We found that the expression of C/EBPα and surfactant proteins increased following SUMO1 knockdown. Furthermore, the relatively low decrease in the levels of C/EBPα sumoylation was correlated with reduced glycogen consumption. Besides, co‐immunoprecipitation assays revealed that sumoylation is involved in the regulation of the interaction between C/EBPα and TGFβ2 in the lung. In conclusion, our findings indicate that sumoylation may act as a negative regulator of the C/EBPα‐mediated transactivation in BPD rats.     

人脐带间充质干细胞抑制卵巢癌的初步研究

目的:从足月剖腹产分娩新生儿脐带中分离出人脐带间充质干细胞(UC-MSCs),探讨其在体外促进SKOV3卵巢癌细胞凋亡,抑制其增殖的作用。方法:新鲜人脐带洗净后剥离动静脉及脐带外膜,得到脐带Wharton's胶。采用组织块贴壁法分离、纯化得到UC-MSCs细胞,光镜下观察UC-MSCs细胞的形态及贴壁生长情况。收集UC-MSCs细胞培养上清,加入SKOV3细胞共培养后,观察不同作用时间(12 h,24 h,36 h,48 h,60 h,72 h)其体外促进SKOV3卵巢癌细胞凋亡,抑制其增殖的作用。结果:光镜下UC-MSCs细胞成长梭状,单核,并成放射或漩涡状排列。PI染色提示,随着UC-MSCs细胞培养上清对SKOV3卵巢癌细胞作用时间的增加,其发生凋亡的细胞数量增多,且具有统计学意义(P0.05)。MTT实验提示SKOV3细胞增殖活力随UC-MSCs细胞培养上清作用时间的增加而显著下降(P0.05),共培养24 h,48 h,72 h的抑制率分别为17.08%,35.36%,46.83%。结论:UC-MSCs在体外具有明显促进SKOV3卵巢癌细胞凋亡,抑制其增殖的作用。     

Elastin synthesis during perinatal lung development in the rat

The rate of soluble elastin synthesis was estimated in lung explants from rats of differing ages to better define periods in lung development important to the deposition of lung elastin. Lungs from rat pups at days 1, 3, 7, 9, 12, 15, and 21 post-parturition and from adult rats were incubated in a defined medium containing L-[3H]valine. Following incubation, labelled soluble elastin (tropoelastin) was separated from other soluble proteins by coacervation and electrophoresis on polyacrylamide gels containing sodium dodecyl sulfate. The tropoelastin synthetic rate was then estimated after correcting for differences in recovery of radioactivity as tropoelastin and lung tissue L-[3H]valine specific activity. Maximal rates of elastin synthesis were observed in lung explants from 7-12-day-old rats. The rate of elastin synthesis during this period was 5-8-times the rate observed in adult rat lung (expressed per g of fresh lung) and represented approx. 2% of the total protein synthesis. Moreover, the values derived from lung explant culture for elastin synthesis were consistent with values for lung elastin deposition in the perinatal rat (5-10 micrograms elastin/h per g lung).     

Genetic regulation of systemic angiogenesis in the mouse lung

The work in this study takes advantage of a new experimental model in the mouse that completely isolates the angiogenic process from the direct effects of ischemia. The model also leads to lung angiogenesis that mimics the vascular source of many lung pathologies, and allows investigation of the temporal and spatial factors that can promote or inhibit angiogenesis. This work describes the expression patterns of genes relevant to pro-angiogenic signals and conditions in response to ischemia in the lung. The most notable changes were increases in the expression of genes involved in inflammation and tissue remodeling. In particular, the results confirm a important role of ELR+ CXC chemokines as proangiogenic signals. In addition, the experimental findings in this mouse lung model show that lung ischemia, rather than hypoxia, is the essential trigger for angiogenesis. Results from this model also suggest potential approaches for determining critical pathways and potential therapeutic strategies related to the control of angiogenesis.     

Overexpression of polo-like kinase 1 and its clinical significance in human non-small cell lung cancer

Polo-like kinase 1 is a serine/threonine kinase which plays an essential role in mitosis and malignant transformation. The aim of this study was to investigate the prognostic significance of polo-like kinase 1 expression and determine its possibility as a therapeutic target in non-small cell lung cancer. Semi-quantitative RT-PCR assay was performed to detect polo-like kinase 1 mRNA expression in non-small cell lung cancer cells or tissues. Immunohistochemistry was performed to detect polo-like kinase 1 protein expression in 100 non-small cell lung cancer tissue samples, and the associations of polo-like kinase 1 expression with clinicopathological factors or prognosis of non-small cell lung cancer patients were evaluated. RNA interference was employed to inhibit endogenous polo-like kinase 1 expression and analyzed the effects of polo-like kinase 1 inhibition on the malignant phenotypes of non-small cell lung cancer cells including growth, apoptosis, radio- or chemoresistance. Also, the possible molecular mechanisms were also investigated. The levels of polo-like kinase 1 mRNA expression in non-small cell lung cancer cell lines or tissues were significantly higher than those in normal human bronchial epithelial cell line or corresponding non-tumor tissues. High polo-like kinase 1 expression was significantly correlated with advanced clinical stage, higher tumor classification and lymph node metastasis of non-small cell lung cancer patients (P = 0.001, 0.004 and 0.001, respectively). Meanwhile, high polo-like kinase 1 protein expression was also an independent prognostic molecular marker for non-small cell lung cancer patients (hazard ratio: 2.113; 95% confidence interval: 1.326-3.557; P = 0.017). Polo-like kinase 1 inhibition could significantly inhibit in vitro and in vivo proliferation, induce cell arrest of G₂/M phase and apoptosis enhancement in non-small cell lung cancer cells, which might be activation of the p53 pathway and the Cdc25C/cdc2/cyclin B1 feedback loop. Further, inhibition of polo-like kinase 1 could enhance the sensitivity of non-small cell lung cancer cells to taxanes or irradiation. Thus, polo-like kinase 1 might be a prognostic marker and a chemo- or radiotherapeutic target for non-small cell lung cancer.