技术资料

Cardiac differentiation of human pluripotent stem cells may be induced under chemically defined conditions,wherein the regulation of Wnt/$\beta$-catenin pathway is often desirable. Here,we examined the effect of trolox,a vitamin E analog,on the cardiac differentiation of human embryonic stem cells (hESCs). 6-Hydroxy-2,5,7,8-tetramethylchromane-2-carboxylic acid (Trolox) significantly enhanced cardiac differentiation in a time- and dose-dependent manner after the mesodermal differentiation of hESCs. Trolox promoted hESC cardiac differentiation through its inhibitory activity against the Wnt/$\beta$-catenin pathway. This study demonstrates an efficient cardiac differentiation method and reveals a novel Wnt/$\beta$-catenin regulator. View Publication

S-glutathionylation of reactive protein cysteines is a post-translational event that plays a critical role in transducing signals from oxidants into biological responses. S-glutathionylation can be reversed by the deglutathionylating enzyme glutaredoxin (GLRX). We have previously demonstrated that ablation of Glrx sensitizes mice to the development of parenchymal lung fibrosis(1). It remains unclear whether GLRX also controls airway fibrosis,a clinical feature relevant to asthma and chronic obstructive pulmonary disease,and whether GLRX controls the biology of airway epithelial cells,which have been implicated in the pathophysiology of these diseases. In the present study we utilized a house dust mite (HDM) model of allergic airway disease in wild type (WT) and Glrx-/- mice on a C57BL/6 background prone to develop airway fibrosis,and tracheal basal stem cells derived from WT mice,global Glrx-/- mice,or bi-transgenic mice allowing conditional ablation of the Glrx gene. Herein we show that absence of Glrx led to enhanced HDM-induced collagen deposition,elevated levels of transforming growth factor beta 1 (TGFB1) in the bronchoalveolar lavage,and resulted in increases in airway hyperresponsiveness. Airway epithelial cells isolated from Glrx-/- mice or following conditional ablation of Glrx showed spontaneous increases in secretion of TGFB1. Glrx-/- basal cells also showed spontaneous TGFB pathway activation,in association with increased expression of mesenchymal genes,including collagen 1a1 and fibronectin. Overall,these findings suggest that GLRX regulates airway fibrosis via a mechanism(s) that involve the plasticity of basal cells,the stem cells of the airways. View Publication

Murine models of myeloid neoplasia show how leukemia infiltration alters the hematopoietic stem cell (HSC) niche to reinforce malignancy at the expense of healthy hematopoiesis. However,little is known about the bone marrow architecture in humans and its impact on clinical outcome. Here,we dissect the bone marrow niche in patients with acute myeloid leukemia (AML) at first diagnosis. We combined immunohistochemical stainings with global gene expression analyses from these AML patients and correlated them with clinical features. Mesenchymal stem and progenitor cells (MSPCs) lost quiescence and significantly expanded in the bone marrow of AML patients. Strikingly,their HSC- and niche-regulating capacities were impaired with significant inhibition of osteogenesis and bone formation in a cell contact-dependent manner through inhibition of cytoplasmic $\beta$-catenin. Assessment of bone metabolism by quantifying peripheral blood osteocalcin levels revealed 30{\%} lower expression in AML patients at first diagnosis than in non-leukemic donors. Furthermore,patients with osteocalcin levels ≤11 ng/mL showed inferior overall survival with a 1-year survival rate of 38.7{\%} whereas patients with higher osteocalcin levels reached a survival rate of 66.8{\%}. These novel insights into the human AML bone marrow microenvironment help translate findings from preclinical models and detect new targets which might pave the way for niche-targeted therapies in AML patients. View Publication

BACKGROUND Cell-surface mucins are expressed in apical epithelial cells of the respiratory tract,and contribute a crucial part of the innate immune system. Despite anti-inflammatory or antiviral functions being revealed for certain cell-surface mucins such as MUC1,the roles of other mucins are still poorly understood,especially in viral infections. METHODS To further identify mucins significant in influenza infection,we screened the expression of mucins in human nasal epithelial cells infected by H3N2 influenza A virus. RESULTS We found that the expression of MUC15 was significantly upregulated upon infection,and specific only to active infection. While MUC15 did not interact with virus particles or reduce viral replication directly,positive correlations were observed between MUC15 and inflammatory factors in response to viral infection. Given that the upregulation of MUC15 was only triggered late into infection when immune factors (including cytokines,chemokines,EGFR and phosphorylated ERK) started to peak and plateau,MUC15 may potentially serve an immunomodulatory function later during influenza viral infection. CONCLUSIONS Our study revealed that MUC15 was one of the few cell-surface mucins induced during influenza infection. While MUC15 did not interact directly with influenza virus,we showed that its increase coincides with the peak of immune activation and thus MUC15 may serve an immunomodulatory role during influenza infection. View Publication

R428 (BGB324) is an anti-cancer drug candidate under clinical investigation. It inhibits the receptor tyrosine kinase Axl and induces apoptosis of many types of cancer cells,but the relationship between the two has not been well established. We investigated the molecular mechanisms of the R428-induced apoptosis and found that R428 induced extensive cytoplasmic vacuolization and caspase activation,independent of its inhibitory effects on Axl. Further analyses revealed that R428 blocked lysosomal acidification and recycling,accumulated autophagosomes and lysosomes,and induced cell apoptosis. Inhibition of autophagy by autophagy inhibitors or autophagic gene-knockout alleviated the R428-induced vacuoles formation and cell apoptosis. Our study uncovered a novel function and mechanism of R428 in addition to its ability to inhibit Axl. These data will help to better direct the application of R428 as an anti-cancer reagent. It also adds new knowledge to understand the regulation of autophagy and apoptosis. View Publication

Remodeling of the actin cytoskeleton through actin dynamics is involved in a number of biological processes,but its role in human stromal (skeletal) stem cells (hMSCs) differentiation is poorly understood. In the present study,we demonstrated that stabilizing actin filaments by inhibiting gene expression of the two main actin depolymerizing factors (ADFs): Cofilin 1 (CFL1) and Destrin (DSTN) in hMSCs,enhanced cell viability and differentiation into osteoblastic cells (OB) in vitro,as well as heterotopic bone formation in vivo. Similarly,treating hMSC with Phalloidin,which is known to stabilize polymerized actin filaments,increased hMSCs viability and OB differentiation. Conversely,Cytocholasin D,an inhibitor of actin polymerization,reduced cell viability and inhibited OB differentiation of hMSC. At a molecular level,preventing Cofilin phosphorylation through inhibition of LIM domain kinase 1 (LIMK1) decreased cell viability and impaired OB differentiation of hMSCs. Moreover,depolymerizing actin reduced FAK,p38 and JNK activation during OB differentiation of hMSCs,while polymerizing actin enhanced these signaling pathways. Our results demonstrate that the actin dynamic reassembly and Cofilin phosphorylation loop is involved in the control of hMSC proliferation and osteoblasts differentiation. View Publication

Adenomyosis is also called internal endometriosis and affects about 20{\%} of reproductive-aged women. It seriously reduces life quality of patients because current drug therapies face with numerous challenges. Long-term clinical application of mifepristone exhibits wonderful therapeutic effects with mild side-effects in many disorders since 1982. Since adenomyosis is a refractory disease,we investigate whether mifepristone can be applied in the treatment of adenomyosis. In this study,we investigated the direct effects of mifepristone on human primary eutopic endometrial epithelial cells and stromal cells in adenomyosis. We found that mifepristone causes cell cycle arrest through inhibiting CDK1 and CDK2 expressions and induces cell apoptosis via the mitochondria-dependent signalling pathway in endometrial epithelial cells and stromal cells of adenomyosis. Furthermore,mifepristone inhibits the migration of endometrial epithelial cells and stromal cells through decreasing CXCR4 expression and restricts the invasion of endometrial epithelial cells via suppression of epithelial-mesenchymal transition in adenomyosis. We also found that mifepristone treatment decreases the uterine volume,CA125 concentration and increases the haemoglobin concentration in serum for adenomyosis patients. Therefore,we demonstrate that mifepristone could serve as a novel therapeutic drug in the treatment of adenomyosis,and therefore,the old dog can do a new trick. View Publication

Malignant cells have a higher nicotinamide adenine dinucleotide (NAD(+)) turnover rate than normal cells,making this biosynthetic pathway an attractive target for cancer treatment. Here we investigated the biologic role of a rate-limiting enzyme involved in NAD(+) synthesis,Nampt,in multiple myeloma (MM). Nampt-specific chemical inhibitor FK866 triggered cytotoxicity in MM cell lines and patient MM cells,but not normal donor as well as MM patients PBMCs. Importantly,FK866 in a dose-dependent fashion triggered cytotoxicity in MM cells resistant to conventional and novel anti-MM therapies and overcomes the protective effects of cytokines (IL-6,IGF-1) and bone marrow stromal cells. Nampt knockdown by RNAi confirmed its pivotal role in maintenance of both MM cell viability and intracellular NAD(+) stores. Interestingly,cytotoxicity of FK866 triggered autophagy,but not apoptosis. A transcriptional-dependent (TFEB) and independent (PI3K/mTORC1) activation of autophagy mediated FK866 MM cytotoxicity. Finally,FK866 demonstrated significant anti-MM activity in a xenograft-murine MM model,associated with down-regulation of ERK1/2 phosphorylation and proteolytic cleavage of LC3 in tumor cells. Our data therefore define a key role of Nampt in MM biology,providing the basis for a novel targeted therapeutic approach. View Publication

The adoption of Warburg metabolism is critical for the activation of macrophages in response to lipopolysaccharide. Macrophages stimulated with lipopolysaccharide increase their expression of nicotinamide phosphoribosyltransferase (NAMPT),a key enzyme in NAD+ salvage,and loss of NAMPT activity alters their inflammatory potential. However,the events that lead to the cells' becoming dependent on NAD+ salvage remain poorly defined. We found that depletion of NAD+ and increased expression of NAMPT occurred rapidly after inflammatory activation and coincided with DNA damage caused by reactive oxygen species (ROS). ROS produced by complex III of the mitochondrial electron-transport chain were required for macrophage activation. DNA damage was associated with activation of poly(ADP-ribose) polymerase,which led to consumption of NAD+. In this setting,increased NAMPT expression allowed the maintenance of NAD+ pools sufficient for glyceraldehyde-3-phosphate dehydrogenase activity and Warburg metabolism. Our findings provide an integrated explanation for the dependence of inflammatory macrophages on the NAD+ salvage pathway. View Publication

Doxorubicin is an anthracycline chemotherapy agent effective in treating a wide range of malignancies,but it causes a dose-related cardiotoxicity that can lead to heart failure in a subset of patients. At present,it is not possible to predict which patients will be affected by doxorubicin-induced cardiotoxicity (DIC). Here we demonstrate that patient-specific human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) can recapitulate the predilection to DIC of individual patients at the cellular level. hiPSC-CMs derived from individuals with breast cancer who experienced DIC were consistently more sensitive to doxorubicin toxicity than hiPSC-CMs from patients who did not experience DIC,with decreased cell viability,impaired mitochondrial and metabolic function,impaired calcium handling,decreased antioxidant pathway activity,and increased reactive oxygen species production. Taken together,our data indicate that hiPSC-CMs are a suitable platform to identify and characterize the genetic basis and molecular mechanisms of DIC. View Publication

Verteporfin (VP),a benzoporphyrin derivative,is clinically used in photodynamic therapy for neovascular macular degeneration. Recent studies indicate that VP may inhibit growth of hepatoma cells without photoactivation through inhibition of YAP-TEAD complex. In this study,we examined the effects of VP without light activation on human retinoblastoma cell lines. Verteporfin but not vehicle control inhibited the growth,proliferation and viability of human retinoblastoma cell lines (Y79 and WERI) in a dose-dependent manner and was associated with downregulation of YAP-TEAD associated downstream proto-oncogenes such as c-myc,Axl,and surviving. In addition VP affected signals involved in cell migration and angiogenesis such as CTGF,cyr61,and VEGF-A but was not associated with significant effect on the mTOR/autophagy pathway. Of interest the pluripotency marker Oct4 were downregulated by Verteporfin treatment. Our results indicate that the clinically used photosensitizer VP is a potent inhibitor of cell growth in retinoblastoma cells,disrupting YAP-TEAD signaling and pluripotential marker OCT4. This study highlights for the first time the role of the YAP-TEAD pathway in Retinoblastoma and suggests that VP may be a useful adjuvant therapeutic tool in treating Rb patients. View Publication

Substoichiometric concentrations of cytochalasin D inhibited the rate of polymerization of actin in 0.5 mM MgCl2,increased its critical concentration and lowered its steady state viscosity. Stoichiometric concentrations of cytochalasin D in 0.5 mM MgCl2 and even substoichiometric concentrations of cytochalasin D in 30 mM KCl,however,accelerated the rate of actin polymerization,although still lowering the final steady state viscosity. Cytochalasin B,at all concentrations in 0.5 mM MgCl2 or in 30 mM KCl,accelerated the rate of polymerization and lowered the final steady state viscosity. In 0.5 mM MgCl2,cytochalasin D uncoupled the actin ATPase activity from actin polymerization,increasing the ATPase rate by at least 20 times while inhibiting polymerization. Cytochalasin B had a very much lower stimulating effect. Neither cytochalasin D nor B affected the actin ATPase activity in 30 mM KCl. The properties of cytochalasin E were intermediate between those of cytochalasin D and B. Cytochalasin D also stimulated the ATPase activity of monomeric actin in the absence of MgCl2 and KCl and,to a much greater extent,stimulated the ATPase activity of monomeric actin below its critical concentration in 0.5 mM MgCl2. Both above and below its critical concentration and in the presence and absence of cytochalasin D,the initial rate of actin ATPase activity,when little or no polymerization had occurred,was directly proportional to the actin concentration and,therefore,apparently was independent of actin-actin interactions. To rationalize all these data,a working model has been proposed in which the first step of actin polymerization is the conversion of monomeric actin-bound ATP,A . ATP,to monomeric actin-bound ADP and Pi,A* . ADP . Pi,which,like the preferred growing end of an actin filament,can bind cytochalasins. View Publication