Time-resolved measurements of PM2.5 carbonaceous aerosols at Gosan, Korea

In order to better understand the characteristics of atmospheric carbonaceous aerosol at a background site in Northeast Asia, semicontinuous organic carbon (OC) and elemental carbon (EC), and time-resolved water-soluble organic carbon (WSOC) were measured by a Sunset OC/ EC and a PILS-TOC (particle-into-liquid sampler coupled with an online total organic carbon) analyzer, respectively, at the Gosan supersite on Jeju Island, Korea, in the summer (May 28-June 17) and fall (August 24-September 30) of 2009. Hourly average OC concentration varied in the range of approximately 0.87-28.38 microgC m-3, with a mean of 4.07+/- 2.60 microgC m-3, while the hourly average EC concentration ranged approximately from 0.04 to 8.19 .microgC m-3, with a mean of 1.35 +/- 0.71 microgC m-3, from May 28 to June 17, 2009. During the fall season, OC varied in the approximate range 0.9-9.6 microgC m-3, with a mean of 2.30 +/-0.80 microgC m-3, whereas EC ranged approximately from 0.01 to 5.40 microgC m-3, with a mean of 0.66 +/- 0.38 microgC m-3. Average contributions of EC to TC and WSOC to OC were 26.0% +/- 9.7% and 20.6% +/-7.4%, and 37.6% +/- 23.5% and 57.2% +/- 22.2% during summer and fall seasons, respectively. As expected, clear diurnal variation of WSOC/OC was found in summer, varying from 0.22 during the nighttime up to 0.72 during the daytime, mainly due to the photo-oxidation process. In order to investigate the effect of air mass pathway on the characteristics of carbonaceous aerosol, 5-day back-trajectory analysis was conducted using the HYSPLIT model. The air mass pathways were classified into four types: Continental (CC), Marine (M), East Sea (ES) and Korean Peninsula (KP). The highest OC/EC ratio of 3.63 was observed when air mass originated from the Continental area (CC). The lowest OC/EC ratio of 0.79 was measured when air mass originated from the Marine area (M). A high OC concentration was occasionally observed at Gosan due to local biomass burning activities. The contribution of secondary OC to total OC varied approximately between 8.4% and 32.2% and depended on air mass type.

MRI of the proximal femur predicts marrow cellularity and the number of mesenchymal stem cells

PURPOSE

To determine whether the marrow conversion index (MCI) in MRI is related to the total number of mononuclear and mesenchymal stem cells (MSCs) in proximal femoral metaphysis of patients with hip osteoarthritis.

MATERIALS AND METHODS

Thirty-two hips of 32 consecutive patients who underwent total hip arthroplasty (THA) for hip osteoarthritis were included in this study. MRI of the hip was performed preoperatively and MCI was subsequently calculated. Three-milliliter bone marrow samples were obtained from the proximal femur during THA and the number of total mononuclear cells was determined using a hemocytometer. Colony forming unit-fibroblasts (CFU-Fs) assays of MSCs were performed by transferring a total of 2 × 10(4) mononuclear cells to each of five 60-mm plates. One week later, the numbers of colonies were counted.

RESULTS

The total number of mononuclear cells decreased with increasing MCI. Likewise, the prevalence and total number of CFU-Fs increased with increasing number of total mononuclear cells, and decreased with increasing MCI.

CONCLUSION

Our results suggest that measurement of MCI in MRI can be an objective and noninvasive method to predict marrow cellularity and the number of MSCs in patients with hip osteoarthritis.

17β-Estradiol, aging, inflammation, and the stress response in the female heart

Heat shock proteins (HSPs) are a cardioprotective class of proteins induced by stress and regulated by the transcription factor, heat shock factor (HSF)-1. 17β-estradiol (E(2)) indirectly regulates HSP expression through rapid activation of nuclear factor-κB (NF-κB) and HSF-1 and protects against hypoxia. As males experience a loss of protective cellular responses in aging, we hypothesized that aged menopausal (old ovariectomized) rats would have an impaired HSP response, which could be prevented by immediate in vivo E(2) replacement. After measuring cardiac function in vivo, cardiac myocytes were isolated from ovariectomized adult and old rats with and without 9 weeks of E(2) replacement. Myocytes were treated with E(2) in vitro and analyzed for activation of NF-κB, HSF-1, and HSP expression. In addition, we measured inflammatory cytokine expression and susceptibility to hypoxia/reoxygenation injury. Cardiac contractility was reduced in old ovariectomized rats and could prevented by immediate E(2) replacement in vivo. Subsequent investigations in isolated cardiac myocytes found that in vitro E(2) activated NF-κB, HSF-1, and increased HSP 72 expression in adult but not old rats. In response to hypoxia/reoxygenation, myocytes from adult, but not old, rats had increased HSP 72 expression. In addition, expression of the inflammatory cytokines TNF-α and IL-1β, as well as oxidative stress, were increased in myocytes from old ovariectomized rats; only the change in cytokine expression could be attenuated by in vivo E(2) replacement. This study demonstrates that while aging in female rats led to a loss of the cardioprotective HSP response, E(2) retains its protective cellular properties.

Role of thioredoxin 1 and thioredoxin 2 on proliferation of human adipose tissue-derived mesenchymal stem cells

Thioredoxin (TRX) is a ubiquitous redox protein that is involved in numerous biological functions, including the first unique step in DNA synthesis. TRX provides control over a number of transcription factors affecting cell proliferation and death through a mechanism referred to as redox regulation. In mammals, there are at least 3 members of the TRX family: TRX1, TRX2, and sperm TRX. To investigate the role of TRX1 and TRX2 in human adipose tissue-derived mesenchymal stem cells (hADSC), we modulated TRX1 and TRX2 expressions in hADSC using a lentiviral gene transfer system and small interfering RNA technique. Reverse transcription-polymerase chain reaction analysis confirmed the changes in expression of TRX1 and TRX2 in lentivirus-transduced or small interfering RNA-transfected cells. Although overexpression of TRX1 and TRX2 did not affect the differentiation of hADSC into adipogenic and osteogenic lineages, it increased the proliferation of hADSC compared with control lentivirus-transduced cells, decreased reactive oxygen species production, and inhibited oxidant-induced cell death. Downregulation of TRX1 and TRX2 inhibited cell proliferation. The treatment of U0126 blocked TRX-induced increase in cell proliferation. Overexpression of TRX1 and TRX2 increased ERK1/2 phosphorylation, nuclear factor-kappaB activation, and β-catenin/Tcf promoter activities and inhibited lucine zipper tumor suppressor 2 expression. On the contrary, downregulation of TRX1 and TRX2 expression induced inhibition of ERK1/2 phosphorylation, nuclear factor-kappaB activation, and β-catenin/Tcf promoter activities and increased lucine zipper tumor suppressor 2 expression. Activation of Wnt signal increased ERK1/2 activities in hADSC. These results indicated that TRX1 and TRX2 regulate the proliferation and survival of hADSC; these processes are mediated by the activation of ERK1/2.

Methods for analyzing microRNA expression and function during osteogenic differentiation of human adipose tissue-derived mesenchymal stem cells

MicroRNAs (miRNA) are single-stranded RNA molecules of 21-23 nucleotides in length that regulate gene expression at the posttranscriptional level. They may play important roles during osteogenic differentiation of adipose tissue-derived mesenchymal stem cells (hASC). In this chapter, we focus on the methods and strategies for elucidating miRNA function during osteogenic differentiation. We describe a miRNA expression analysis protocol, and a lentiviral vector strategy for the ectopic expression of miRNA in hASC to determine the role of miRNA during osteogenic differentiation. We also describe miRNA inhibition to further determine the role of miRNA during osteogenic differentiation, and a luciferase assay to demonstrate direct binding between a specific miRNA and its putative target.

Effect of the modulation of leucine zipper tumor suppressor 2 expression on proliferation of various cancer cells functions as a tumor suppressor

β-catenin is a component of the adhesion complex linking cadherin and actin cytoskeleton, as well as a major mediator of the Wnt pathway, which is a critical signal cascade regulating embryonic development, cell polarity, carcinogenesis, and stem cell function. NF-κB functions as a key regulator of immune responses and apoptosis, and mutations in NF-κB signaling can lead to immune diseases and cancers. We previously showed that NF-κB-mediated modulation of β-catenin/Tcf signaling is mediated by leucine zipper tumor suppressor 2 (Lzts2) and that lzts2 expression is differentially regulated in various cancer cells. Its functional significances, however, are poorly understood. We showed that NF-κB-induced modulation of β-catenin/Tcf pathway is regulated by lzts2 expression in mesenchymal stem cells (MSCs) and several cancer cells, and that NF-κB-induced lzts2 expression is differentially regulated among cancer cell types. Here, using a promoter-reporter assay and EMSA, we demonstrate that NF-κB regulates lzts2 transcription by directly binding to the lzts2 promoter, and that NF-κB-induced lzts2 transcription differs by cell types. Modulation of lzts2 expression by lentiviral techniques affected proliferation and tumorigenicity of several cancer cell lines such as breast, colon, prostate cancer, and glioma, but did not affect cisplatin sensitivity or cell migration. Our data indicate that lzts2 expression is transcriptionally regulated by NF-κB activities, and the modulation of lzts2 expression affects cell proliferation and tumor growth through the Wnt/β-catenin pathway in various cancer cell lines.

Adipose-derived stromal cells inhibit allergic airway inflammation in mice

Allergic asthma is an inflammatory airway disease caused by T helper type 2 (Th2)-driven immune responses. Recent studies have demonstrated that adipose-derived stromal cells (ASC) have an immunosuppressive effect on T-cell activity. This study was performed to investigate whether ASC can inhibit Th2-dependent allergic airway inflammation in mice. BALB/c mice were sensitized to ovalbumin (OVA) by intraperitoneal injection. To investigate the effect of ASC on the development of asthma phenotypes, 2 × 10⁶ ASC were injected intravenously before OVA challenge. We evaluated the airway hyperresponsiveness (AHR), the proportion of eosinophils and cytokine production in bronchoalveolar lavage fluid (BALF), airway inflammation, and the intracellular cytokine staining of T cells in the BALF and spleen. Airway hyperresponsiveness, airway eosinophilia, and mucus production were markedly reduced after ASC administration before OVA challenge. The increased interleukin (IL)-4, IL-5, and transforming growth factor (TGF)-β1 levels in the BALF after OVA challenge were significantly reduced by the administration of ASC. This inhibition was accompanied by decreased IL-4(+) CD4(+) T cells and increased interferon (IFN)-γ(+) CD4(+) T cells in the BALF and spleen. The results of this study suggest that ASC administration before an allergen challenge inhibits AHR, lung inflammation, and Th2 cytokine production induced by an allergen challenge through inhibition of Th2 cell activity.

Notch1 mediates visfatin-induced FGF-2 up-regulation and endothelial angiogenesis

AIMS

Our aims were to determine the role of Notch1 in mediating visfatin-induced angiogenesis and to explore potential target genes involved.

METHODS AND RESULTS

Inhibition of Notch signalling attenuated visfatin-induced angiogenesis in vitro, ex vivo, and in vivo. Visfatin increased γ-secretase activity, Notch1 cleavage and activation, and Hes1 gene induction. Visfatin also stimulated fibroblast growth factor-2 (FGF-2) gene expression in a Notch1-dependent manner. Enforced expression of active Notch1 intracellular domain increased FGF-2 protein levels and stimulated endothelial tube formation, whereas blocking Notch1 signalling or knockdown of Notch1 by small interfering RNA suppressed visfatin-induced FGF-2 up-regulation and angiogenesis. Reporter analysis of FGF-2 promoter revealed the presence of CSL (CBF-1, suppressor of hairless, LAG-1)-binding site, and chromatin immunoprecipitation analysis demonstrated the binding of Notch1-CSL complex to this site in response to visfatin.

CONCLUSION

Our data provide the first example of Notch1-dependent endothelial FGF-2 induction by visfatin and of Notch1 activation in visfatin-stimulated endothelial angiogenesis, suggesting that the signalling axis of visfatin/Notch1/angiogenic factors like FGF-2 might be a valuable target for pathological angiogenesis.

MiR-21 regulates adipogenic differentiation through the modulation of TGF-beta signaling in mesenchymal stem cells derived from human adipose tissue

A better understanding of the molecular mechanisms that govern human adipose tissue-derived mesenchymal stem cells (hASCs) differentiation could improve hASCs-based cell therapy and provide new insights into a number of diseases, including obesity. In this study, we examined the roles of microRNA-21 (miR-21) in adipogenic differentiation of hASCs. We found that miR-21 expression was transiently increased after induction of adipogenic differentiation, peaked at 3 days, and returned to the baseline level 8 days. Lentiviral overexpression of miR-21 enhanced adipogenic differentiation. Overexpression of miR-21 decreased both protein and mRNA levels of TGFBR2. The expression of TGFBR2 was decreased during adipogenic differentiation of hASCs in concordance with an increase in the level of miR-21. In contrast, inhibiting miR-21 with 2'-O-methyl-antisense microRNA increased TGFBR2 protein levels in hASCs, accompanied by decreased adipogenic differentiation. The activity of a luciferase construct containing the miR-21 target site from the TGFBR2 3'UTR was lower in LV-miR21-infected hASCs than in LV-miLacZ infected cells. TGF-beta-induced inhibition of adipogenic differentiation was significantly decreased in miR-21 overexpressing cells compared with control lentivirus-transduced cells. RNA interference-mediated downregulation of SMAD3, but not of SMAD2, increased adipogenic differentiation. Overexpression and inhibition of miR-21 altered SMAD3 phosphorylation without affecting total levels of SMAD3 protein. Our data are the first to demonstrate that the role of miR-21 in the adipogenic differentiation of hASCs is mediated through the modulation of TGF-beta signaling. This study improves our knowledge of the molecular mechanisms governing hASCs differentiation, which may underlie the development of obesity or other metabolic diseases.

NF-kappaB activation stimulates osteogenic differentiation of mesenchymal stem cells derived from human adipose tissue by increasing TAZ expression

Tumor necrosis factor-alpha (TNF-alpha) is a skeletal catabolic agent that stimulates osteoclastogenesis and inhibits osteoblast function. Although TNF-alpha inhibits the mineralization of osteoblasts, the effect of TNF-alpha on mesenchymal stem cells (MSC) is not clear. In this study, we determined the effect of TNF-alpha on osteogenic differentiation of stromal cells derived from human adipose tissue (hADSC) and the role of NF-kappaB activation on TNF-alpha activity. TNF-alpha treatment dose-dependently increased osteogenic differentiation over the first 3 days of treatment. TNF-alpha activated ERK and increased NF-kappaB promoter activity. PDTC, an NF-kappaB inhibitor, blocked the osteogenic differentiation induced by TNF-alpha and TLR-ligands, but U102, an ERK inhibitor, did not. Overexpression of miR-146a induced the inhibition of IRAK1 expression and inhibited basal and TNF-alpha- and TLR ligand-induced osteogenic differentiation. TNF-alpha and TLR ligands increased the expression of transcriptional coactivator with PDZ-binding motif (TAZ), which was inhibited by the addition of PDTC. A ChIP assay showed that p65 was bound to the TAZ promoter. TNF-alpha also increased osteogenic differentiation of human gastroepiploic artery smooth muscle cells. Our data indicate that TNF-alpha enhances osteogenic differentiation of hADSC via the activation of NF-kappaB and a subsequent increase of TAZ expression.

The role of chemokines in proangiogenic action induced by human adipose tissue-derived mesenchymal stem cells in the murine model of hindlimb ischemia

The proangiogenic action of human adipose tissue-derived mesenchymal stem cells (hASCs) transplantation has been shown to be mediated by secretory factors. In this study, we determined if human granulocyte chemotactic protein-2(GCP2) or monocyte chemoattractant protein-1(MCP1) is involved in the proangiogenic action of hASCs transplantation in the hindlimb ischemia model. hASCs secrete GCP2 and MCP1, which leads to increased tubule formation. The downregulation of GCP2 or MCP1 decreased MCP1 and GCP2 secretion, respectively, whereas the external addition of GCP2 or MCP1 increased MCP1 and GCP2, respectively. Additionally, the treatment of GCP2 and MCP1 increased VEGF secretion, while the downregulation of GCP2 and MCP1 showed the opposite effect on VEGF secretion. Downregulation of GCP2 and MCP1 expression also inhibited hASCs-induced proangiogenic action, while the overexpression of GCP2 increased it. Finally, the downregulation of MCP1 or VEGF inhibited the GCP2 overexpression-induced increase in blood flow recovery. Taken together, these data indicate that the proangiogenic action of hASCs transplantation is mediated by the interaction between GCP2, MCP1 and VEGF, which are secreted from the transplanted cells.

Beneficial Effect of Pentoxifylline on Cisplatin-Induced Acute Renal Failure in Rabbits

Pentoxifylline (PTX) has been reported to inhibit TNF-alpha production and prevent several types of acute renal failure. This study was undertaken to determine the effect of PTX on the cisplatin-induced acute renal failure in rabbits. Rabbits received a single injection of cisplatin (5 mg/kg, i.p.) with or without PTX pretreatment (30 mg/kg, i.v.). Alterations in renal function, apoptotic cell death, and TNF-alpha mRNA expression were measured at 24 or 48 h after cisplatin injection. Cisplatin caused an increase in BUN and serum creatinine levels, a reduction in GFR, and an increase in fractional Na+ excretion. Such changes were significantly attenuated by PTX pretreatment (30 mg/kg, i.p.) 30 min before and 24 h after cisplatin injection. Morphological evaluation showed that cisplatin injection induced diffuse proximal tubular necrosis and the effect was reduced by PTX pretreatment. Cisplatin induced apoptotic cell death in renal cortex and the effect was significantly prevented by PTX. Treatment of opossum kidney cells with cisplatin resulted in cell death, which was significantly prevented by PTX. The increase in lipid peroxidation and the decrease in renal blood flow induced by cisplatin were not affected by PTX. The expression of TNF-alpha mRNA was increased after cisplatin injection and the effect was inhibited by PTX pretreatment. These results suggest that cisplatin-induced acute renal failure in rabbits is associated with an induction of TNF-alpha-mediated apoptosis, and that PTX may exert a protective effect against cisplatin nephrotoxicity by inhibiting TNF-alpha production.

IFATS collection: Immunomodulatory effects of adipose tissue-derived stem cells in an allergic rhinitis mouse model

Adipose tissue-derived stem cells (ASCs) exhibit immunosuppressive effects in allogeneic transplantation. However, there is no report that evaluates the in vivo immune-modulating effect of ASCs in an experimental allergic rhinitis (AR) model. We investigated whether ASCs migrate to the nasal mucosa in an AR mouse model and evaluated the immune-modulating effect of ASCs in the AR mouse model. Cultured ASCs (2 x 10(6)) were injected i.v. before the first allergen challenge in the AR mouse model. Migration of ASCs to the nasal mucosa was evaluated by immunofluorescence. The immunomodulatory effects of ASCs were evaluated by nasal symptoms, histology, serum ovalbumin (OVA)-specific antibody, and the cytokine profile of the spleen. ASCs migrated to the nasal mucosa in the AR mouse model. ASCs significantly reduced allergic symptoms and inhibited eosinophilic inflammation in the nasal mucosa. ASCs significantly decreased the serum allergen-specific IgE level and the IgG(1)/IgG(2a) ratio and significantly increased the IgG(2a) level in the AR mouse model. ASCs inhibited interleukin (IL)-4 and IL-5 production from OVA-incubated splenocytes, but enhanced interferon-gamma production. In conclusion, ASCs can migrate to the nasal mucosa in the AR mouse model and inhibit eosinophilic inflammation partly via shifting to a T-helper 1 (Th1) from a Th2 immune response to allergens.

Combination of oncolytic adenoviral therapy with chemotherapy for enhanced breast cancer cell killing

Abstract #2129

Oncolytic adenoviruses are emerging agents for treatment of cancer by tumor-restricted virus replication, cell lysis and virus spread. A promising oncolytic adenovirus agent, known as Ad5-24-RGD, harbors a 24-bp deletion in the E1A gene that abrogates the binding of E1A to the retinoblastoma tumor suppressor (Rb) and presents enhanced infectivity of primary cancer cells due to insertion of an Arg-Gly-Asp (RGD) motif into the fiber knob. Thus, Ad5-24-RGD has improved cancer cell infection efficiency due to expanded tropism toward alpha-v integrins. It also replicates selectively in cancer cells with Rb/p16 mutations. As with conventional therapy regimes, oncolytic virotherapy, by itself, has limited success in complete tumor eradication in both preclinical animal models and clinical studies. Combination of anticancer agents with different modes of action remains a mainstay in cancer treatment. We undertook one approach towards this end by combining oncolytic adenoviral therapy with chemotherapy. In this study, we investigated a combination treatment of breast cancer cells with Ad5-4-RGD and Docetaxel, a microtubule-stabilizing taxane that is being used in the clinic for the treatment of breast and prostate cancers and small cell carcinoma of the lung. Our results indicate a synergistic effect between Docetaxel and Ad5-24-RGD in breast cancer cell killing at a lower dose than either agent alone. These results suggest that viral replication was not inhibited by this chemotherapy treatment and that chemotherapy could reduce the amount of viral particles needed to help eradicate the tumor. Administration of lower viral loads would simultaneously improve safety and decrease immunogenicity of the vector. Likewise lower doses of chemotherapy agents would decrease toxicity and side effects. The inclusion of oncolytic adenoviruses into multimodal cancer treatment together with chemotherapy has a potential to become powerful therapeutic regimen.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 2129.

Alterations in the proangiogenic functions of adipose tissue-derived stromal cells isolated from diabetic rats

Cardiovascular complications in diabetic patients have been reported to be related to the impaired proangiogenic actions of endothelial progenitor cells. In this study, we investigated the functions of adipose tissue-derived stromal cells (ASCs) in diabetes. We induced type I diabetes in rats by a intraperitoneal injection of 60 mg/kg of streptozotocin (STZ) and type II diabetes by the combined treatment of high fat diet and 45 mg/kg of STZ. Rat ASCs (rASCs) isolated from the adipose tissues in the interscapular and abdominal region of type I or type II diabetic rats showed lower proliferating ability than those of control rats. Diabetic rASCs showed lower blood flow recovery than those of control rats in a hindlimb ischemia model of nude mouse. When ASCs isolated from rat and human were exposed to high glucose concentrations, their proliferating abilities and improved blood flow in a hindlimb ischemia model were compromised, compared with ASCs that were maintained at control glucose concentrations. However, the same concentrations of mannitol did not affect these characteristics. Exposure of human ASCs (hASCs) to high glucose concentrations increased reactive oxygen species (ROS) production, and the addition of ROS scavengers [N-acetylcysteine (NAC) or catalase] to high glucose media partially decreased the high glucose-induced inhibitory effect on proliferating ability in hASCs. However, hASCs treated with high glucose medium for 6 days showed lower proliferation in control culture medium, which was not recovered by the addition of NAC or catalase. These data indicate that ASCs isolated from diabetic rats and exposed at high concentration of glucose have an impaired proangiogenic action and that the functional impairment is partly due to ROS generated by chronic exposure to high glucose concentrations.

Transforming growth factor-beta1 regulates the fate of cultured spinal cord-derived neural progenitor cells

OBJECTIVES

We have evaluated the physiological roles of transforming growth factor-beta1 (TGF-beta1) on differentiation, migration, proliferation and anti-apoptosis characteristics of cultured spinal cord-derived neural progenitor cells.

METHODS

We have used neural progenitor cells that had been isolated and cultured from mouse spinal cord tissue, and we also assessed the relevant reaction mechanisms using an activin-like kinase (ALK)-specific inhibitory system including an inhibitory RNA, and found that it involved potential signalling molecules such as phosphatidylinositol-3-OH kinase (PI3K)/Akt and mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK1/2).

RESULTS AND CONCLUSIONS

Transforming growth factor-beta1-mediated cell population growth was activated after treatment and was also effectively blocked by an ALK41517-synthetic inhibitor (4-(5-benzo(1,3) dioxol-5-yl-4-pyridine-2-yl-1H-imidazole-2-yl) benzamide (SB431542) and ALK siRNA, thereby indicating the involvement of SMAD2 in the TGF-beta1-mediated growth and migration of these neural progenitors cells (NPC). In the present study, TGF-beta1 actively induced NPC migration in vitro. Furthermore, TGF-beta1 demonstrated extreme anti-apoptotic behaviour against hydrogen peroxide-mediated apoptotic cell death. At low dosages, TGF-beta1 enhanced (by approximately 76%) cell survival against hydrogen peroxide treatment via inactivation of caspase-3 and -9. TGF-beta1-treated NPCs down-regulated Bax expression and cytochrome c release; in addition, the cells showed up-regulated Bcl-2 and thioredoxin reductase 1. They also had increased p38, Akt and ERK1/2 phosphorylation, showing the involvement of both the PI3K/Akt and MAPK/ERK1/2 pathways in the neuroprotective effects of TGF-beta1. Interestingly, these effects operate on specific subtypes of cells, including neurones, neural progenitor cells and astrocytes in cultured spinal cord tissue-derived cells. Lesion sites of spinal cord-overexpressing TGF-beta1-mediated prevention of cell death, cell growth and migration enhancement activity have been introduced as a possible new basis for therapeutic strategy in treatment of neurodegenerative disorders, including spinal cord injuries.

Mesenchymal stem cells derived from human adipose tissues favor tumor cell growth in vivo

Mesenchymal stem cells (MSCs) have generated a great deal of interest in clinical situations, due principally to their potential use in regenerative medicine and tissue engineering applications. However, the therapeutic application of MSCs remains limited, unless the favorable effects of MSCs for tumor growth in vivo and the long-term safety of the clinical applications of MSCs can be understood more thoroughly. In this study, MSCs derived from human adipose tissues (hASCs) together with tumor cells were transplanted subcutaneously or intracranially into BALB/c nude mice to observe tumor outgrowth. The results indicated that hASCs with H460 or U87MG cells promoted tumor growth in nude mice. Our histopathological analyses indicated that the co-injection of tumor cells with hASCs exerted no influence on the formation of intratumoral vessels. Co-culture of tumor cells with hASCs or the addition of conditioned medium (CM) from hASCs effected an increase in the proliferation of H460 or U87MG cells. Co-injection of hASCs with tumor cells effected an increase in tumor cell viability in vivo, and also induced a reduction in apoptotic cell death. CM from hASCs inhibited hydrogen peroxide-induced cell death in H460 or U87MG cells. These findings indicated that MSCs could favor tumor growth in vivo. Thus, it is necessary to conduct a study concerning the long-term safety of this technique before MSCs can be used as therapeutic tools in regenerative medicine and tissue engineering.

Role of MyD88 in TLR agonist-induced functional alterations of human adipose tissue-derived mesenchymal stem cells

Toll-like receptors (TLRs) sense microorganism components and are critical host mediators of inflammation during infection. Recently, TLRs have been reported to be involved in cell proliferation and differentiation. We previously reported that TLR agonists might affect proliferation and differentiation of human adipose tissue-derived mesenchymal stem cells (hASCs). In this study, we sought to determine whether TLR signaling is dependent on MyD88 in hASCs. The hASCs were downregulated using LV-GFP-miR-MyD88, a lentiviral construct inserted siRNA against human MyD88 that significantly inhibited cell proliferation. MyD88 downregulation reduced NF-kappaB activation and enhancement of osteogenic differentiation induced by peptidoglycan (PGN) more significantly than that induced by lipopolysaccharide (LPS). Although LPS- and PGN-induced cytokine secretions were decreased greatly by MyD88 downregulation, IFN-gamma-induced protein-10 (IP10) and IFNbeta expression were enhanced by LPS irrespective of the downregulation of MyD88. These results suggest that TLR signaling is mediated via MyD88-independent pathways as well as MyD88-dependent pathways in hASCs and that MyD88 contributes to the regulation of cell proliferation and differentiation in hASCs.

Differential effect of NF-kappaB activity on beta-catenin/Tcf pathway in various cancer cells

beta-Catenin/Tcf and NF-kappaB pathways play an important role in biological functions. We determined the underlying mechanisms of differential interaction between two pathways in various human cancer cell lines. NF-kappaB positively regulated beta-catenin/Tcf pathways in human glioblastoma, whereas it has an opposite effect on beta-catenin/Tcf pathways in colon, liver, and breast cancer cells. Expression of lucine zipper tumor suppressor 2 (lzts2) was positively regulated by NF-kappaB activity in colon, liver, and breast cancer cells, whereas negatively regulated in glioma cells. Downregulation of lzts2 increased the beta-catenin/Tcf promoter activity and inhibited NF-kappaB-induced modulation of the nuclear translocation of beta-catenin. These data indicate that the differential crosstalk between beta-catenin/Tcf and NF-kappaB pathway in various cancer cells is resulted from the differences in the regulation of NF-kappaB-induced lzts2 expression.

Cancer-derived lysophosphatidic acid stimulates differentiation of human mesenchymal stem cells to myofibroblast-like cells

Lysophosphatidic acid (LPA) is enriched in ascites of ovarian cancer patients and is involved in growth and invasion of ovarian cancer cells. Accumulating evidence suggests cancer-associated myofibroblasts play a pivotal role in tumorigenesis through secreting stromal cell-derived factor-1 (SDF-1). In the present study, we demonstrate that LPA induces expression of alpha-smooth muscle actin (alpha-SMA), a marker for myofibroblasts, in human adipose tissue-derived mesenchymal stem cells (hADSCs). The LPA-induced expression of alpha-SMA was completely abrogated by pretreatment of the cells with Ki16425, an antagonist of LPA receptors, or by silencing LPA(1) or LPA(2) isoform expression with small interference RNA (siRNA). LPA elicited phosphorylation of Smad2/3, and siRNA-mediated depletion of endogenous Smad2/3 or adenoviral expression of Smad7, an inhibitory Smad, abrogated the LPA induced expression of alpha-SMA and phosphorylation of Smad2/3. LPA-induced secretion of transforming growth factor (TGF)-beta1 in hADSCs, and pretreatment of the cells with SB431542, a TGF-beta type I receptor kinase inhibitor, or anti-TGF-beta1 neutralizing antibody inhibited the LPA-induced expression of alpha-SMA and phosphorylation of Smad2. Furthermore, ascites from ovarian cancer patients or conditioned medium from ovarian cancer cells induced expression of alpha-SMA and phosphorylation of Smad2, and pretreatment of the cells with Ki16425 or SB431542 abrogated the expression of alpha-SMA and phosphorylation of Smad2. In addition, LPA increased the expression of SDF-1 in hADSCs, and pretreatment of the cells with Ki16425 or SB431562 attenuated the LPA-stimulated expression of SDF-1. These results suggest that cancer-derived LPA stimulates differentiation of hADSCs to myofibroblast-like cells and increases SDF-1 expression through activating autocrine TGF-beta1-Smad signaling pathway.

Role of Wnt5a in the proliferation of human glioblastoma cells

Wnt5a operates as either a tumor suppressor or a tumor stimulator, according to tumor type. The functions of Wnt5a in human glioblastoma (GBM) have yet to be determined. We initially evaluated the expression of Wnt5a in human glioma. The results of immunohistochemical analyses have revealed that Wnt5a expression was higher in human GBM than in normal brain tissue and low-grade astrocytoma. In order to assess the role of Wnt5a on proliferation in human glioblastoma cells, we employed U87MG and GBM-05, a newly established GBM cell line. GBM-05 was established from a patient diagnosed with GBM. GBM-05 cells were shown to express Nestin, but did not express GFAP and Map2ab. GBM-05 cells formed infiltrating brain tumors after being intracerebrally transplanted into nude mice, and xenotransplanted GBM-05 cells were observed to differentiate into neuronal and astrocyte lineages. Wnt5a expression in the xenotransplanted tumors was higher than that detected in the surrounding brain tissues. The overexpression of Wnt5a increased the proliferation of GBM-05 and U87MG in vitro. By way of contrast, the downregulation of Wnt5a expression as the result of RNA interference reduced proliferation from GBM-05 and U87MG cells in vitro, and reduced tumorigenicity in vivo. Our data indicate that Wnt5a signaling is an important regulator in the proliferation of human glioma cells.