References of "FASEB Journal"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailRac1 GTPase silencing counteracts microgravity-induced effects on osteoblastic cells.
Guignandon, Alain; Fauré, Céline; Neutelings, Thibault et al

in FASEB Journal (2014), 28(9), 4077-4087

Bone cells exposed to real microgravity display alterations of their cytoskeleton and focal adhesions, two major mechanosensitive structures. These structures are controlled by small GTPases of the Ras ... [more ▼]

Bone cells exposed to real microgravity display alterations of their cytoskeleton and focal adhesions, two major mechanosensitive structures. These structures are controlled by small GTPases of the Ras homology (Rho) family. We investigated the effects of RhoA, Rac1, and Cdc42 modulation of osteoblastic cells under microgravity conditions. Human MG-63 osteoblast-like cells silenced for RhoGTPases were cultured in the automated Biobox bioreactor (European Space Agency) aboard the Foton M3 satellite and compared to replicate ground-based controls. The cells were fixed after 69 h of microgravity exposure for postflight analysis of focal contacts, F-actin polymerization, vascular endothelial growth factor (VEGF) expression, and matrix targeting. We found that RhoA silencing did not affect sensitivity to microgravity but that Rac1 and, to a lesser extent, Cdc42 abrogation was particularly efficient in counteracting the spaceflight-related reduction of the number of focal contacts [-50% in silenced, scrambled (SiScr) controls vs. -15% for SiRac1], the number of F-actin fibers (-60% in SiScr controls vs. -10% for SiRac1), and the depletion of matrix-bound VEGF (-40% in SiScr controls vs. -8% for SiRac1). Collectively, these data point out the role of the VEGF/Rho GTPase axis in mechanosensing and validate Rac1-mediated signaling pathways as potential targets for counteracting microgravity effects [less ▲]

Detailed reference viewed: 4 (0 ULg)
Full Text
Peer Reviewed
See detailHyperglycosylated human chorionic gonadotropin stimulates angiogenesis through TGF-beta receptor activation.
Berndt, Sarah; Blacher, Silvia ULg; Munaut, Carine ULg et al

in FASEB Journal (2013), 27(4), 1309-21

Embryo implantation requires extensive angiogenesis at the maternal-fetal interface. Hyperglycosylated human chorionic gonadotropin (hCG-H), a trophoblast invasive signal produced by extravillous ... [more ▼]

Embryo implantation requires extensive angiogenesis at the maternal-fetal interface. Hyperglycosylated human chorionic gonadotropin (hCG-H), a trophoblast invasive signal produced by extravillous cytotrophoblasts and by choriocarcinoma, was evaluated for its angiogenic role. hCG-H was purified by HPLC from choriocarcinoma supernatant, and the glycosylation pattern was determined by 2D gel analysis. Angiogenesis models used were aortic ring assay with wild-type and LHCGR-knockout mice, endothelial and mural cell proliferation, and migration assays. The TGF-beta signaling pathway was studied by coimmunoprecipitation, competitive binding, TGF-beta reporter gene assays, and Smad immunoblotting. hCG-H displayed a potent angiogenic effect [3.2-fold increase of number of vessel intersections in wild-type aortic rings (11.406 to 36.964)]. hCG-H-induced angiostimulation was independent of the classic hCG signaling pathway since it persisted in LHCGR-knockout mice [4.73-fold increase of number of vessel intersections (10.826 to 51.288)]. Using TGF-beta signaling inhibitors, Tbeta-RII was identified as the hCG-H receptor responsible for its angiogenic switch. hCG-H exposure enhanced phosphorylation of Smad 2 in endothelial and mural cells and genomic activation of Smad-responsive elements. Interaction between hCG-H and Tbeta-RII was demonstrated by coimmunoprecipitation and binding competition with (125)I-TGF-beta. This new paracrine interaction between trophoblast and endothelial cells through the hCG-H and the TGF-beta receptor complex plays a key role in angiogenesis associated with placental development and tumorigenesis. [less ▲]

Detailed reference viewed: 34 (7 ULg)
Full Text
Peer Reviewed
See detailDisease-related amyloidogenic variants of human lysozyme trigger the unfolded protein response and disturb eye development in Drosophila melanogaster
Kumita, Janet R.; Helmfors, Linda; Williams, Jocy et al

in FASEB Journal (2012)

We have created a Drosophila model of lysozyme amyloidosis to investigate the in vivo behavior of disease-associated variants. To achieve this objective, wild-type (WT) protein and the amyloidogenic ... [more ▼]

We have created a Drosophila model of lysozyme amyloidosis to investigate the in vivo behavior of disease-associated variants. To achieve this objective, wild-type (WT) protein and the amyloidogenic variants F57I and D67H were expressed in Drosophila melanogaster using the UAS-gal4 system and both the ubiquitous and retinal expression drivers Act5C-gal4 and gmr-gal4. The nontransgenic w(1118) Drosophila line was used as a control throughout. We utilized ELISA experiments to probe lysozyme protein levels, scanning electron microscopy for eye phenotype classification, and immunohistochemistry to detect the unfolded protein response (UPR) activation. We observed that expressing the destabilized F57I and D67H lysozymes triggers UPR activation, resulting in degradation of these variants, whereas the WT lysozyme is secreted into the fly hemolymph. Indeed, the level of WT was up to 17 times more abundant than the variant proteins. In addition, the F57I variant gave rise to a significant disruption of the eye development, and this correlated to pronounced UPR activation. These results support the concept that the onset of familial amyloid disease is linked to an inability of the UPR to degrade completely the amyloidogenic lysozymes prior to secretion, resulting in secretion of these destabilized variants, thereby leading to deposition and associated organ damage.-Kumita, J. R., Helmfors, L., Williams, J., Luheshi, L. M., Menzer, L., Dumoulin, M., Lomas, D. A., Crowther, D. C., Dobson, C. M., Brorsson, A.-C. Disease-related amyloidogenic variants of human lysozyme trigger the unfolded protein response and disturb eye development in Drosophila melanogaster. [less ▲]

Detailed reference viewed: 29 (15 ULg)
Full Text
Peer Reviewed
See detailCell cholesterol modulates metalloproteinase-dependent shedding of low-density lipoprotein receptor-related protein-1 (LRP-1) and clearance function.
Selvais, C.; D'Auria, L.; Tyteca, D. et al

in FASEB Journal (2011), 25(8), 2770-2781

Low-density lipoprotein receptor-related protein-1 (LRP-1) is a plasma membrane scavenger and signaling receptor, composed of a large ligand-binding subunit (515-kDa α-chain) linked to a shorter ... [more ▼]

Low-density lipoprotein receptor-related protein-1 (LRP-1) is a plasma membrane scavenger and signaling receptor, composed of a large ligand-binding subunit (515-kDa α-chain) linked to a shorter transmembrane subunit (85-kDa β-chain). LRP-1 cell-surface level and function are controlled by proteolytic shedding of its ectodomain. Here, we identified ectodomain sheddases in human HT1080 cells and demonstrated regulation of the cleavage by cholesterol by comparing the classical fibroblastoid type with a spontaneous epithelioid variant, enriched ∼2-fold in cholesterol. Two membrane-associated metalloproteinases were involved in LRP-1 shedding: a disintegrin and metalloproteinase-12 (ADAM-12) and membrane-type 1 matrix metalloproteinase (MT1-MMP). Although both variants expressed similar levels of LRP-1, ADAM-12, MT1-MMP, and specific tissue inhibitor of metalloproteinases-2 (TIMP-2), LRP-1 shedding from epithelioid cells was ∼4-fold lower than from fibroblastoid cells. Release of the ectodomain was triggered by cholesterol depletion in epithelioid cells and impaired by cholesterol overload in fibroblastoid cells. Modulation of LRP-1 shedding on clearance was reflected by accumulation of gelatinases (MMP-2 and MMP-9) in the medium. We conclude that cholesterol exerts an important control on LRP-1 levels and function at the plasma membrane by modulating shedding of its ectodomain, and therefore represents a novel regulator of extracellular proteolytic activities.-Selvais, C., D'Auria, L., Tyteca, D., Perrot, G, Lemoine, P., Troeberg, L., Dedieu, S., Noël, A., Nagase, H., Henriet, P., Courtoy, P. J., Marbaix, E., Emonard, H. Cell cholesterol modulates metalloproteinase-dependent shedding of low-density lipoprotein receptor-related protein-1 (LRP-1) and clearance function. [less ▲]

Detailed reference viewed: 41 (1 ULg)
Full Text
Peer Reviewed
See detailPostnatal and adult exposure to estradiol differentially influences adult neurogenesis in the main and accessory olfactory bulb of female mice.
Veyrac, Alexandra; Bakker, Julie ULg

in FASEB Journal (2011), 25(3), 1048-57

Neurons incorporated into the adult main olfactory bulb (MOB) and accessory olfactory bulb (AOB) derive from the subventricular zone (SVZ). Despite some recent studies on the role of olfactory ... [more ▼]

Neurons incorporated into the adult main olfactory bulb (MOB) and accessory olfactory bulb (AOB) derive from the subventricular zone (SVZ). Despite some recent studies on the role of olfactory neurogenesis in sociosexual behaviors mediated by hormones, data on the implication of estrogens are still lacking. Taking advantage of female aromatase-knockout (ArKO) mice, which are unable to produce estradiol across their life span, we investigated the role of estradiol exposure during early postnatal and adult periods on adult neurogenesis in the MOB and AOB. We found that proliferation of progenitor cells in the adult female SVZ was not influenced by estradiol. However, whereas adult exposure to estradiol influences the turnover of MOB newborn neurons, the survival of those in the AOB depends on exposure to estradiol during the early postnatal period. Finally, based on their expression of Zif268, we showed that newborn neurons in the MOB responded to sociosexual odors, albeit to a lesser extent in ArKO females, suggesting a contribution of estradiol during the early postnatal period to this response. Together, these results suggest that the survival and functional integration of newborn neurons in the adult female MOB and AOB are differentially influenced by estrogens from the early postnatal period to adulthood. [less ▲]

Detailed reference viewed: 9 (4 ULg)
Full Text
Peer Reviewed
See detailSoluble forms of VEGF receptor-1 and -2 promote vascular maturation via mural cell recruitment.
LORQUET, Sophie ULg; Berndt, Sarah; Blacher, Silvia ULg et al

in FASEB Journal (2010), 24(10), 3782-95

Two soluble forms of vascular endothelial growth factor (VEGF) receptors, sVEGFR-1 and sVEGFR-2, are physiologically released and overproduced in some pathologies. They are known to act as anti-VEGF ... [more ▼]

Two soluble forms of vascular endothelial growth factor (VEGF) receptors, sVEGFR-1 and sVEGFR-2, are physiologically released and overproduced in some pathologies. They are known to act as anti-VEGF agents. Here, we report that these soluble receptors contribute to vessel maturation by mediating a dialogue between endothelial cells (EC) and mural cells that leads to blood vessel stabilization. Through a multidisciplinary approach, we provide evidences that these soluble VEGF receptors promote mural cell migration through a paracrine mechanism involving interplay in EC between VEGF/VEGFR-2 and sphingosine-1- phosphate type-1 (S1P)/S1P1 pathways that leads to endothelial nitric oxyde synthase (eNOS) activation. This new paradigm is supported by the finding that sVEGFR-1 and -2: 1) induce an eNOS-dependent outgrowth of a mural cell network in an ex vivo model of angiogenesis, 2) increase the mural cell coverage of neovessels in vitro and in vivo, 3) promote mural cell migration towards EC, 4) stimulate endothelial S1P1 overproduction and eNOS activation that promote the migration and the recruitment of neighboring mural cells. These findings provide new insights into mechanisms regulating physiological and pathological angiogenesis and vessel stabilization. [less ▲]

Detailed reference viewed: 144 (44 ULg)
Full Text
Peer Reviewed
See detailLymphangiogenesis: in vitro and in vivo models
Bruyère, Françoise; Noël, Agnès ULg

in FASEB Journal (2010), 24(1), 8-21

Lymphangiogenesis, the formation of new lymphatic vessels from preexisting ones, is an important biological process associated with diverse pathologies, such as metastatic dissemination and graft ... [more ▼]

Lymphangiogenesis, the formation of new lymphatic vessels from preexisting ones, is an important biological process associated with diverse pathologies, such as metastatic dissemination and graft rejection. In addition, lymphatic hypoplasia characterizes lymphedema, usually a progressive and lifelong condition for which no curative treatment exists. Much progress has been made in recent years in identifying molecules specifically expressed on lymphatic vessels and in the setting up of in vitro and in vivo models of lymphangiogenesis. These new tools rapidly provided an abundance of information on the mechanisms underlying lymphatic development and the progression of diseases associated with lymphatic dysfunction. In this review, we describe the common in vitro and in vivo models of lymphangiogenesis that have proven suitable for investigating lymphatic biology and the interactions occurring between lymphatic vessels and other cells, such as immune cells and cancer cells. Their rationales and limitations are discussed and illustrated by the most informative findings obtained with them. [less ▲]

Detailed reference viewed: 98 (17 ULg)
Full Text
See detailTargeting TGFbeta Bioavailability to Regulate Vascular Stability and Leakage
Sounni, Nor Eddine ULg; Van Kempen, Leon; Dehne, Kerstin et al

in FASEB Journal (2007, April), 2007; 21:lb33

Detailed reference viewed: 15 (3 ULg)
Full Text
Peer Reviewed
See detailIncreased Inflammation Delays Wound Healing in Mice Deficient in Collagenase-2 (MMP-8)
Gutierrez-Fernandez, A.; Inada, M.; Balbin, M. et al

in FASEB Journal (2007), 21(10), 2580-91

Matrix metalloproteinases (MMPs) have been implicated in numerous tissue-remodeling processes. The finding that mice deficient in collagenase-2 (MMP-8) are more susceptible to develop skin cancer ... [more ▼]

Matrix metalloproteinases (MMPs) have been implicated in numerous tissue-remodeling processes. The finding that mice deficient in collagenase-2 (MMP-8) are more susceptible to develop skin cancer, prompted us to investigate the role of this protease in cutaneous wound healing. We have observed a significant delay in wound closure in MMP8-/- mice and an altered inflammatory response in their wounds, with a delay of neutrophil infiltration during the first days and a persistent inflammation at later time points. These changes were accompanied by alterations in the TGF-beta1 signaling pathway and by an apoptosis defect in MMP8-/- mice. The delay in wound healing observed in MMP8-/- mice was rescued by bone marrow transplantation from wild-type mice. Analysis of other MMPs showed that MMP8-/- mice had a significant increase in the expression of MMP-9, suggesting that both proteases might act coordinately in this process. This possibility was further supported by the novel finding that MMP-8 and MMP-9 form specific complexes in vivo. Taken together, these data indicate that MMP-8 participates in wound repair by contributing to the resolution of inflammation and open the possibility to develop new strategies for treating wound healing defects. [less ▲]

Detailed reference viewed: 58 (1 ULg)
Full Text
Peer Reviewed
See detailDefensis induce the recruitment of dendritic cells in cervical human papillomavirus-associated (pre)neoplastic lesions formed in vitro and transplanted in vivo
Hubert, Pascale ULg; Herman, Ludivine ULg; Maillard, Catherine ULg et al

in FASEB Journal (2007), 21(11), 2765-75

In addition to their direct antimicrobial activity, defensins might also influence adaptive immunity by attracting immature dendritic cells (DC). As these cells have been shown to be deficient in uterine ... [more ▼]

In addition to their direct antimicrobial activity, defensins might also influence adaptive immunity by attracting immature dendritic cells (DC). As these cells have been shown to be deficient in uterine cervix carcinogenesis, we evaluated the ability of -defensin (HNP-2, human neutrophil defensin 2) and ß-defensin (HßD2, human beta defensin 2) to stimulate their migration in human papillomavirus (HPV)-associated (pre)cancers. We first observed, using RT-PCR and immunohistology, that HßD2 is absent in HPV-transformed keratinocytes and that it is weakly expressed in cervical (pre)neoplastic lesions in comparison with normal keratinocytes. We next demonstrated that defensins exert a chemotactic activity for DC in a Boyden Chamber assay and stimulate their infiltration in an in vitro-formed (pre)neoplastic epithelium (organotypic culture of HPV-transformed keratinocytes). To evaluate the ability of defensins also to recruit DC in vivo, we developed a model of immunodeficient mice grafted with organotypic cultures of HPV+ keratinocytes, which form an epithelium similar to a high-grade neoplastic lesion, with tumoral invasion and neovascularization. Intravenously injected human DC were able to infiltrate grafts of HPV+ keratinocytes after administration of HNP-2 in the transplantation chamber. Taken together, these results suggest that defensins could reverse a frequent immune alteration observed in cancer development. [less ▲]

Detailed reference viewed: 58 (19 ULg)
Full Text
Peer Reviewed
See detailAngiogenic activity of human chorionic gonadotropin through LH receptor activation on endothelial and epithelial cells of the endometrium
Berndt, Sarah ULg; PERRIER d'HAUTERIVE, Sophie ULg; Blacher, Silvia ULg et al

in FASEB Journal (2006), 20(14), 2630-2632

Successful embryo development requires an extensive endometrial angiogenesis in proximity of implantation site. The glycoprotein hCG is produced even before implantation by trophoblast in normal pregnancy ... [more ▼]

Successful embryo development requires an extensive endometrial angiogenesis in proximity of implantation site. The glycoprotein hCG is produced even before implantation by trophoblast in normal pregnancy. In this manuscript, we demonstrate an angiogenic effect of hCG in several in vivo (chick chorioallantoic membrane, matrigel plug assay, aortic ring assay) and in vitro experimental models. In contrast, human placental lactogen (hPL) did not display angiogenic properties. LH/hCG receptor was detected in endothelial cells by reverse-transcriptase polymerase chain reaction (RT-PCR) and by Western blotting. In mice aortic ring assay, angiostimulation by hCG was abrogated by deletion of LH/hCG receptor (LuRKO mice). Use of recombinant hCG and anti-hCG antibody (Ab) further confirmed the specificity of this angiogenic activity. By using dibutyryl cAMP, adenylate cyclase, or protein kinase A inhibitors, we demonstrate that hCG-mediated angiogenesis involves adenylyl-cyclase-protein kinase A activation. Addition of hCG to endometrial epithelial epithelial cells, but not to cultured endothelial cells, stimulated vascular endothelial growth factor (VEGF). VEGF and hCG also displayed additive activities. Altogether, these data demonstrate that peritrophoblastic angiostimulation may result from a paracrine dialogue between trophoblast, epithelial, and endothelial cells through hCG and VEGF. [less ▲]

Detailed reference viewed: 76 (12 ULg)
Full Text
Peer Reviewed
See detailDelayed GM-CSF treatment stimulates axonal regeneration and functional recovery in paraplegic rats via an increased BDNF expression by endogenous macrophages
Bouhy, Delphine; Malgrange, Brigitte ULg; Multon, Sylvie ULg et al

in FASEB Journal (2006), 20(8), 12391241

Macrophages (monocytes/microglia) could play a critical role in central nervous system repair. We have previously found a synchronism between the regression of spontaneous axonal regeneration and the ... [more ▼]

Macrophages (monocytes/microglia) could play a critical role in central nervous system repair. We have previously found a synchronism between the regression of spontaneous axonal regeneration and the deactivation of macrophages 3-4 wk after a compression-injury of rat spinal cord. To explore whether reactivation of endogenous macrophages might be beneficial for spinal cord repair, we have studied the effects of granulocyte-macrophage colony stimulating factor (GM-CSF) in the same paraplegia model and in cell cultures. There was a significant, though transient, improvement of locomotor recovery after a single delayed intraperitoneal injection of 2 mu g GM-CSF, which also increased significantly the expression of Cr3 and brain-derived neurotrophic factor ( BDNF) by macrophages at the lesion site. At longer survival delays, axonal regeneration was significantly enhanced in GMCSF-treated rats. In vitro, BV2 microglial cells expressed higher levels of BDNF in the presence of GM-CSF and neurons cocultured with microglial cells activated by GM-CSF generated more neurites, an effect blocked by a BDNF antibody. These experiments suggest that GM-CSF could be an interesting treatment option for spinal cord injury and that its beneficial effects might be mediated by BDNF.-Bouhy, D., Malgrange, B., Multon, S., Poirrier, A. L., Scholtes, F., Schoenen, J., Franzen, R. Delayed GM-CSF treatment stimulates axonal regeneration and functional recovery in paraplegic rats via an increased BDNF expression by endogenous macrophages. [less ▲]

Detailed reference viewed: 32 (6 ULg)
Full Text
Peer Reviewed
See detailTargeted calretinin expression in granule cells of calretinin-null mice restores normal cerebellar functions
Bearzatto, Bertrand; Servais, Laurent; Roussel, Céline et al

in FASEB Journal (2006), 20

SPECIFIC AIMS Inactivation of gene coding for calretinin, a calcium binding protein acting as a fast calcium buffer, deeply altered the cerebellar physiology leading to motor discoordination. Although ... [more ▼]

SPECIFIC AIMS Inactivation of gene coding for calretinin, a calcium binding protein acting as a fast calcium buffer, deeply altered the cerebellar physiology leading to motor discoordination. Although mechanistic hypotheses have been proposed to explain these alterations, the widespread expression of calretinin in the whole central nervous system and its expression in several neuronal types in the cerebellar circuitry preclude a precise mechanistic demonstration. The aim of this study was to determine to what extent the expression of calretinin in a specific neuronal cell type, the cerebellar granule cells, contributes to the phenotype detected in calretinin knockout (Cr–/–) mice. To achieve this objective, we constructed transgenic Cr–/– mice exhibiting a selective re-expression of Cr in granule cells (hereafter referred to as Cr-rescue) through the promoter function of the GABAA receptor {alpha}6 subunit gene. [less ▲]

Detailed reference viewed: 31 (7 ULg)
Full Text
Peer Reviewed
See detailAnti-tumor effect of caveolin gene delivery are mediated through the inhibition of the pro-angiogenic and vasodilatating effect of nitric oxide
Brouet, A.; DeWever, Julie; MARTINIVE, Philippe ULg et al

in FASEB Journal (2005)

In tumors, caveolin-1, the structural protein of caveolae, constitutes a key switch through its function as a tumor suppressor and a promoter of metastases. In endothelial cells (EC), caveolin is also ... [more ▼]

In tumors, caveolin-1, the structural protein of caveolae, constitutes a key switch through its function as a tumor suppressor and a promoter of metastases. In endothelial cells (EC), caveolin is also known to directly interact with the endothelial nitric oxide synthase (eNOS) and thereby to modulate nitric oxide (NO)-mediated processes including vasodilation and angiogenesis. In this study, we examined whether the modulation of the stoichiometry of the caveolin/eNOS complex in EC lining tumor blood vessels could affect the tumor vasculature and consecutively tumor growth. For this purpose, we used cationic lipids, which are delivery systems effective at targeting tumor vs. normal vascular networks. We first documented that in vitro caveolin transfection led to the inhibition of both VEGF-induced EC migration and tube formation on Matrigel. The DNA-lipocomplex was then administered through the tail vein of tumor-bearing mice. The direct interaction between recombinant caveolin and native eNOS was validated in coimmunoprecipitation experiments from tumor extracts. A dramatic tumor growth delay was observed in mice transfected with caveolin- vs. sham-transfected animals. Using laser Doppler imaging and microprobes, we found that in the early time after lipofection (e.g., when macroscopic effects on the integrity of the tumor vasculature were not detectable), caveolin expression impaired NO-dependent tumor blood flow. At later stages post-transfection, a decrease in tumor microvessel density in the central core of caveolin-transfected tumors was also documented. In conclusion, our study reveals that by exploiting the exquisite regulatory interaction between eNOS and caveolin and the propensity of cationic lipids to target EC lining tumor blood vessels, caveolin plasmid delivery appears to be a safe and efficient way to block neoangiogenesis and vascular function in solid tumors, independently of any direct effects on tumor cells. [less ▲]

Detailed reference viewed: 28 (8 ULg)
Full Text
Peer Reviewed
See detailContribution of Host MMP-2 and MMP-9 to Promote Tumor Vascularization and Invasion of Malignant Keratinocytes
Masson, Véronique ULg; de la Ballina, L. R.; Munaut, Carine ULg et al

in FASEB Journal (2005), 19(2), 234-6

The matrix metalloproteinases (MMPs) play a key role in normal and pathological angiogenesis by mediating extracellular matrix degradation and/or controlling the biological activity of growth factors ... [more ▼]

The matrix metalloproteinases (MMPs) play a key role in normal and pathological angiogenesis by mediating extracellular matrix degradation and/or controlling the biological activity of growth factors, chemokines, and/or cytokines. Specific functions of individual MMPs as anti- or proangiogenic mediators remain to be elucidated. In the present study, we assessed the impact of single or combined MMP deficiencies in in vivo and in vitro models of angiogenesis (malignant keratinocyte transplantation and the aortic ring assay, respectively). MMP-9 was predominantly expressed by neutrophils in tumor transplants, whereas MMP-2 and MMP-3 were stromal. Neither the single deficiency of MMP-2, MMP-3, or MMP-9, nor the combined absence of MMP-9 and MMP-3 did impair tumor invasion and vascularization in vivo. However, there was a striking cooperative effect in double MMP-2:MMP-9-deficient mice as demonstrated by the absence of tumor vascularization and invasion. In contrast, the combined lack of MMP-2 and MMP-9 did not impair the in vitro capillary outgrowth from aortic rings. These results point to the importance of a cross talk between several host cells for the in vivo tumor promoting and angiogenic effects of MMP-2 and MMP-9. Our data demonstrate for the first time in an experimental model that MMP-2 and MMP-9 cooperate in promoting the in vivo invasive and angiogenic phenotype of malignant keratinocytes. [less ▲]

Detailed reference viewed: 61 (6 ULg)
Full Text
Peer Reviewed
See detailHistone deacetylase HDAC8 associates with smooth muscle alpha-actin and is essential for smooth muscle cell contractility
Waltregny, David ULg; Glenisson, Wendy; Tran, Syv Li et al

in FASEB Journal (2005), 19(8), 966-968

Although originally characterized as nuclear enzymes controlling the stability of nucleosomes, histone deacetylases (HDACs) may also exert their activity within the cytosol. Recently, we have demonstrated ... [more ▼]

Although originally characterized as nuclear enzymes controlling the stability of nucleosomes, histone deacetylases (HDACs) may also exert their activity within the cytosol. Recently, we have demonstrated that HDAC8, a class I HDAC, is a novel, prominently cytosolic marker of smooth muscle differentiation. As HDAC8 displays a striking stress fiber-like pattern of distribution and is coexpressed in vivo with smooth muscle alpha-actin (alpha-SMA) and smooth muscle myosin heavy chain, we have explored the possible participation of this HDAC in smooth muscle cytoskeleton regulation. Cell fractionation assays performed with primary human smooth muscle cells (HSMCs) showed that HDAC8, in contrast to HDAC1 and HDAC3, was enriched in cytoskeleton-bound protein fractions and insoluble cell pellets, suggesting an association of HDAC8 with the cystoskeleton. Coimmunoprecipitation experiments using HSMCs, NIH-3T3 cells, and human prostate tissue lysates further demonstrated that HDAC8 associates with alpha-SMA but not with beta-actin. HDAC8 silencing through RNA interference strongly reduced the capacity of HSMCs to contract collagen lattices. Mock transfections had no effect on HSMC contractily, and transfections with small interfering RNAs (siRNAs) specific for HDAC6, a cytosolic HDAC that functions as an alpha-tubulin deacetylase, resulted in a weak contraction inhibition. Although mock- and HDAC6 siRNA-transfected HSMCs showed no noticeable morphological changes, HDAC8 siRNA-transfected HSMCs displayed a size reduction with diminished cell spreading after replating. Altogether, our findings indicate that HDAC8 associates with the smooth muscle actin cytoskeleton and may regulate the contractile capacity of smooth muscle cells. [less ▲]

Detailed reference viewed: 40 (4 ULg)
Full Text
Peer Reviewed
See detailPlasmin-activated doxorubicin prodrugs containing a spacer reduce tumor growth and angiogenesis without systemic toxicity
Devy, L.; de Groot, F. M.; Blacher, Silvia ULg et al

in FASEB Journal (2004), 18(3), 565-567

To generate doxorubicin (Dox) specifically at the tumor site, the chemotherapeutic agent was incorporated into a prodrug by linkage to a peptide specifically recognized by plasmin, which is overproduced ... [more ▼]

To generate doxorubicin (Dox) specifically at the tumor site, the chemotherapeutic agent was incorporated into a prodrug by linkage to a peptide specifically recognized by plasmin, which is overproduced in many cancers. ST-9905, which contains an elongated self-elimination spacer, is activated more rapidly in vitro by plasmin than is ST-9802. Prodrug activation in vitro depended on the level of urokinase produced by tumor cells and was inhibited by aprotinin, a plasmin inhibitor. Comparison of equimolar concentrations of ST-9905, ST-9802, and Dox in EF43.fgf-4 and MCF7 models revealed that both prodrugs, in sharp contrast to Dox, displayed antiproliferative and antiangiogenic activities without discernible toxicity. Although MCF7 cells are poor urokinase producers in vitro, prodrug efficacy in this model may be explained by production of plasmin by tumor-infiltrating host cells. Mice treated with equitoxic concentrations (maximum tolerated doses) of prodrugs showed 100% survival and negligible body weight loss, in contrast to results after Dox treatment. ST-9905 was substantially more effective than ST9802 and induced similar tumor growth inhibition as Dox but without apparent toxicity. This finding may be explained by the elongated spacer, which facilitates enzymatic prodrug activation. These data validate both the use of elongated spacers in vivo and the concept of targeting anticancer prodrugs to tumor-associated plasmin. [less ▲]

Detailed reference viewed: 21 (0 ULg)
Full Text
Peer Reviewed
See detailThe Inhibition of Cyclin-Dependent Kinases Induces Differentiation of Supernumerary Hair Cells and Deiters' Cells in the Developing Organ of Corti
Malgrange, Brigitte ULg; Knockaert, Marie; Belachew, Shibeshih ULg et al

in FASEB Journal (2003), 17(14), 2136-8

In the embryonic day 19 organs of Corti, we showed that roscovitine, a chemical inhibitor of cyclin-dependent kinases (CDKs), significantly increased the number of hair cells (HCs) and corresponding ... [more ▼]

In the embryonic day 19 organs of Corti, we showed that roscovitine, a chemical inhibitor of cyclin-dependent kinases (CDKs), significantly increased the number of hair cells (HCs) and corresponding supporting cells (SCs) by triggering differentiation of precursor cells without interacting with cell proliferation. The effect of roscovitine was mimicked by other CDK1, 2, 5, and 7 inhibitors but not by CDK4/6 and mitogen-activated protein kinase pathway antagonists. Immunohistochemical analysis indicated that roscovitine-specific intracellular targets, CDK1, 2, 5, and 7, were expressed in the organ of Corti and especially in Hensen's cells. Affinity chromatography studies showed a tight correlation between the protein levels of CDK1/2 and 5 and the rate of roscovitine-induced supernumerary cells in the organ of Corti. In addition, we demonstrated that basal CDK activity was higher and more roscovitine-sensitive at developmental stages that are selectively permissive for the emergence of supernumerary cells. These results suggest that CDKs are involved in the normal development of the organ of Corti and that, at least in E19 embryos, inhibition of CDKs is sufficient to trigger the differentiation of HCs and corresponding SCs, presumably from the Hensen's cell progenitors and/or from progenitors located in the greater epithelial ridge area. [less ▲]

Detailed reference viewed: 9 (0 ULg)
Full Text
Peer Reviewed
See detailMMP-2 and MMP-9 synergize in promoting choroidal neovascularization
Lambert, Vincent ULg; Wielockx, B.; Munaut, Carine ULg et al

in FASEB Journal (2003), 17(15), 2290-2292

Matrix metalloproteinase 2 (MMP-2) and MMP-9 are increased in human choroidal neovascularization (CNV) occurring during the exudative most aggressive form of age-related macular degeneration (AMD), but ... [more ▼]

Matrix metalloproteinase 2 (MMP-2) and MMP-9 are increased in human choroidal neovascularization (CNV) occurring during the exudative most aggressive form of age-related macular degeneration (AMD), but their precise role and potential interactions remain unclear. To address the question of MMP-2 and MMP-9 functions, mice deficient in the expression of MMP-2 (MMP-2 KO), MMP-9 (MMP-9 KO), and both MMP-2 and MMP-9 (MMP-2,9 KO) with their corresponding wild-type mice (WT) underwent CNV induction by laser-induced rupture of the Bruch's membrane. Both the incidence and the severity of CNV were strongly attenuated in double deficient compared with single gene deficient mice or corresponding WT controls. The reduced neovascularization was accompanied by fibrinogen/fibrin accumulation. Furthermore, overexpression of the endogenous MMP inhibitors TIMP-1 or TIMP-2 (delivered by adenoviral vectors) in WT mice or daily injection of a synthetic and gelatinase selective MMP inhibitor (Ro 26-2853) significantly decreased the pathological reaction. These findings suggest that MMP-2 and MMP-9 may cooperate in the development of AMD and that their selective inhibition represents an alternative strategy for the treatment of choroidal neovascularization. [less ▲]

Detailed reference viewed: 17 (1 ULg)
Full Text
Peer Reviewed
See detailMT1-MMP expression promotes tumor growth and angiogenesis through an up-regulation of vascular endothelial growth factor expression
Sounni, Nor Eddine ULg; Devy, L.; Hajitou, A. et al

in FASEB Journal (2002), 16(6), 555-564

Membrane type 1 metalloprotease (MT1-MMP) is a transmembrane metalloprotease that plays a major role in the extracellular matrix remodeling, directly by degrading several of its components and indirectly ... [more ▼]

Membrane type 1 metalloprotease (MT1-MMP) is a transmembrane metalloprotease that plays a major role in the extracellular matrix remodeling, directly by degrading several of its components and indirectly by activating pro-MMP2. We investigated the effects of MT1-MMP overexpression on in vitro and in vivo properties of human breast adenocarcinoma MCF7 cells, which do not express MT1-MMP or MMP-2. MT1-MMP and MMP-2 cDNAs were either transfected alone or cotransfected. All clones overexpressing MT1-MMP 1) were able to activate endogenous or exogenous pro-MMP-2, 2) displayed an enhanced in vitro invasiveness through matrigel-coated filters independent of MMP-2 transfection, 3) induced the rapid development of highly vascularized tumors when injected subcutaneously in nude mice, and 4) promoted blood vessels sprouting in the rat aortic ring assay. These effects were observed in all clones overexpressing MT1-MMP regardless of MMP-2 expression levels, suggesting that the production of MMP-2 by tumor cells themselves does not play a critical role in these events. The angiogenic phenotype of MT1-MMP-producing cells was associated with an up-regulation of VEGF expression. These results emphasize the importance of MT1-MMP during tumor angiogenesis and open new opportunities for the development of anti-angiogenic strategies combining inhibitors of MT1-MMP and VEGF antagonists. [less ▲]

Detailed reference viewed: 66 (10 ULg)