Effects on mechanical stretch on human osteoblasts: role of the Rho family GTPases in the mechano-transduction.
Neutelings, Thibaut ; ; Nusgens, Betty et al
Poster (2010, May 21)Detailed reference viewed: 14 (3 ULg)
Role of the netrin-like domain of procollagen C-proteinase enhancer-1 in the control of metalloproteinase activity.
; ; Colige, Alain et al
in Journal of Biological Chemistry (2010), 285(21), 15950-9Detailed reference viewed: 10 (0 ULg)
Comparison between platelet-rich plasma (PRP) and vascular endothelial growth factor-111 (VEGF-111) as a therapeutic tool in tendon healing process
Kaux, Jean-François ; Drion, Pierre ; Libertiaux, Vincent et al
Poster (2010, March 20)
Introduction In spite of the availability of various treatments for tendinopathy, this pathology often becomes chronic. For this reason, it is of interest to develop new treatments. Among them, the ... [more ▼]
Introduction In spite of the availability of various treatments for tendinopathy, this pathology often becomes chronic. For this reason, it is of interest to develop new treatments. Among them, the injection of platelet-rich plasma (PRP) seems to be a promising one. Indeed, several animal models have demonstrated that injection of blood platelets can initiate and stimulate tendon and ligament repair by releasing growth factors (GF) locally. Among all the GF released by activated platelets, the vascular endothelial growth factor-A (VEGF-A) is known to induce positive effects on vascular function and angiogenesis, and could be implicated in the healing process of tendons. Recently, a novel VEGF-A isoform was identified, the VEGF-111, a biologically active and proteolysis-resistant VEGF-A isoform, also known to present beneficial effects on ischemic diseases. This prompted us to evaluate whether VEFF-111 would have a therapeutic interest within the framework of the tendon pathology. Aim of the study: We hypothesized that the healing of ruptured Achilles tendons, which is the last stage of the Blazina’s classification, could be improved by injection of VEGF-111 that was compared to the potential effect of PRP injections using a rat model. Methods: A 5mm defect was surgically induced in rat Achilles tendon after resection of plantaris tendon. Rats were divided into 3 groups: A: control (no injection), B: PRP treatment and C: VEGF-111 treatment. Rats received a local injection of PRP (50µL) or VEGF-111 (100ng) in situ after the surgery and were placed in their cage without immobilization. After 5, 15 and 30 days, the rats were euthanized in each group. The traumatized Achilles tendon of each rat was removed and dissected during the healing process. Immediately after sampling, tendons were submitted to a biomechanical tensile test up to rupture, using a “Cryo-jaw”. Results: Our results show that developed force necessary to induce tendon rupture during biomechanical tensile test was more important for tendons which had received an injection of PRP or VEGF-111. Moreover, the tensile force necessary to break tendons is higher with PRP than with VEGF-111. These results were already noticed from day 5 onwards. Conclusion: This experimentation has shown that both PRP and VEGF-111 injections stimulated tendon healing process as suggested by the increased force needed to break tendons during its healing process. Furthermore, this acceleration of the cicatrisation process was more significant with PRP than with VEGF-111. This could be explained by the release from platelets of a “cocktail” of growth factors acting in synergy on the healing process. Acknowledgement This experimentation was partially financed by “Standard de Liège 2007” and “Lejeune-Lechien 2008” grants. [less ▲]Detailed reference viewed: 134 (33 ULg)
ADAMTS-2: procollagen processing and implications in genetic and acquired diseases.
Conference (2010, March)Detailed reference viewed: 15 (0 ULg)
VEGF111, a new VEGF-A isoform induced by genotoxic agents; resistance to proteolytic
; Colige, Alain ; DELGAUDINE, Marie et al
Conference (2010)Detailed reference viewed: 16 (8 ULg)
Comparison of chitosan/siRNA and trimethylchitosan/siRNA complexes behaviour in vitro
Dehousse, Vincent ; Garbacki, Nancy ; Jaspart, Séverine et al
in International Journal of Biological Macromolecules (2010), 46
Chitosan and trimethylchitosan (TMC)-siRNA nanoparticles were produced by simple complexation technique or by ionic gelation using tripolyphosphate (TPP). The obtained complexes were characterized in ... [more ▼]
Chitosan and trimethylchitosan (TMC)-siRNA nanoparticles were produced by simple complexation technique or by ionic gelation using tripolyphosphate (TPP). The obtained complexes were characterized in terms of physicochemical properties such as size, zeta potential, complexation efficiency and stability. Furthermore, cytotoxicity, cell uptake and transfection efficiency of polyplexes were evaluated in vitro. Under pH condition of cell culture medium, a strong decrease in siRNA condensation efficiency was observed with chitosan nanoparticles. This characteristic resulted in low transfection efficiencies in HEK293 cell line. Formulation of chitosan polyplexes with TPP led to improvement of polyplexes stability but no significant increase in transfection efficiency was observed compared to simple chitosan complexes. By contrast, TMC complexes did not have pH dependency on siRNA complexation. TMCsiRNA nanoparticles were stable in physiological condition. Accordingly, cellular uptake was increased compared to chitosan polyplexes. However, improvement of transfection efficiency was low regarding to cellular uptake of these complexes. Chitosan and TMC complexes present some characteristics favourable for siRNA delivery, such as ability to integrate siRNA into small discrete particles or low toxicity of the complexes. This study also highlights the importance of complexes stability in physiological environment for siRNA transfection purposes. [less ▲]Detailed reference viewed: 96 (32 ULg)
Development of pH–responsive nanocarriers using trimethylchitosans and methacrylic acid copolymer for siRNA delivery
Dehousse, Vincent ; Garbacki, Nancy ; Colige, Alain et al
in Biomaterials (2010), 31
RNA interference-based therapies are dependent on intracellular delivery of siRNA. The release of siRNA from the endosomal compartment may be a rate limiting step in the transfection process. The purpose ... [more ▼]
RNA interference-based therapies are dependent on intracellular delivery of siRNA. The release of siRNA from the endosomal compartment may be a rate limiting step in the transfection process. The purpose of this study was to produce pH–responsive nanocarriers made of trimethylchitosan (TMC). To this end, pHsensitive methacrylic acid (MAA) copolymer was added to TMC–siRNA formulations. Four different TMCs associated or not with MAA were evaluated as siRNA carriers. Nanoparticles were characterized in terms of size, surface charge, morphology and interaction with siRNA. A swelling behaviour due to a decrease in pH was observed and was found to be dependent on MAA content in the complexes. In vitro experiments aimed at evaluating how the capacity of the nanocarriers to transfect siRNA in L929 cells was affected by MAA content. Confocal microscopy experiments showed that fluorescent MAA-containing particles exhibit a different distribution pattern inside the cells comparing to their counterpart without this pH-sensitive polymer. Transfection efficiency was investigated by RhoA mRNA expression inhibition. MAA–TMC–siRNA complexes were able to transfect L929 cells with greater efficiency than corresponding TMC–siRNA complexes. This study gives an insight into the opportunity of pH-sensitive nanocarriers for siRNA delivery. Such formulations may represent an attractive strategy to improve endosomal escape of siRNA. [less ▲]Detailed reference viewed: 61 (21 ULg)
Alternative splicing: a promising target for pharmaceutical inhibition of pathological angiogenesis?
Munaut, Carine ; Colige, Alain ; Lambert, Charles
in Current Pharmaceutical Design (2010), 16(35), 3864-76
In eukaryotes, genes consist in coding sequences (exons) interspersed with non-coding ones (introns). The regulation of alternative inclusion/exclusion of exons, or part of exons, during the maturation of ... [more ▼]
In eukaryotes, genes consist in coding sequences (exons) interspersed with non-coding ones (introns). The regulation of alternative inclusion/exclusion of exons, or part of exons, during the maturation of the pre-mRNA into mRNA (alternative splicing) allows a dramatic increase of the protein versus the gene repertoire. In a number of cases, alternative splicing decision generates proteins with distinct, sometimes opposite, functions from a given gene. Angiogenesis is the process of vascularisation in physiological conditions and a series of pathologies, including cancer where it favours tumour progression and dissemination of metastasis. In this issue, we discuss some key examples showing how alternative splicing may induce a switch from anti-angiogenic to pro-angiogenic functions and reciprocally. For some of these splicing events, the molecular mechanisms that trigger alternative splicing toward one or the other direction start to be elucidated. The emergence of strategies enabling to regulate alternative splicing opens new routes for anti-angiogenic therapies. [less ▲]Detailed reference viewed: 24 (6 ULg)
ADAMTS-2 functions as anti-angiogenic and anti-tumoral molecule independently of its catalytic activity.
Dubail, Johanne ; ; Deroanne, Christophe et al
in Cellular & Molecular Life Sciences (2010)
ADAMTS-2 is a metalloproteinase that plays a key role in the processing of fibrillar procollagen precursors into mature collagen molecules by excising the amino-propeptide. We demonstrate that recombinant ... [more ▼]
ADAMTS-2 is a metalloproteinase that plays a key role in the processing of fibrillar procollagen precursors into mature collagen molecules by excising the amino-propeptide. We demonstrate that recombinant ADAMTS-2 is also able to reduce proliferation of endothelial cells, and to induce their retraction and detachment from the substrate resulting in apoptosis. Dephosphorylation of Erk1/2 and MLC largely precedes the ADAMTS-2 induced morphological alterations. In 3-D culture models, ADAMTS-2 strongly reduced branching of capillary-like structures formed by endothelial cells and their long-term maintenance and inhibited vessels formation in embryoid bodies (EB). Growth and vascularization of tumors formed in nude mice by HEK 293-EBNA cells expressing ADAMTS-2 were drastically reduced. A similar anti-tumoral activity was observed when using cells expressing recombinant deleted forms of ADAMTS-2, including catalytically inactive enzyme. Nucleolin, a nuclear protein also found to be associated with the cell membrane, was identified as a potential receptor mediating the antiangiogenic properties of ADAMTS-2. [less ▲]Detailed reference viewed: 71 (27 ULg)
Histological and transcriptional study of angiogenesis and lymphangiogenesis in uninvolved skin, acute pinpoint lesions and established psoriasis plaques: an approach of vascular development chronology in psoriasis
Henno, Audrey ; Blacher, Silvia ; Lambert, Charles et al
in Journal of Dermatological Science (2010), 57(3), 162-169
Background Dysregulation of angiogenesis and lymphangiogenesis could participate in psoriasis pathogenesis. Analysis of nascent psoriasis lesions should help at identifying early vascular anomalies ... [more ▼]
Background Dysregulation of angiogenesis and lymphangiogenesis could participate in psoriasis pathogenesis. Analysis of nascent psoriasis lesions should help at identifying early vascular anomalies. Objective To analyse vascular development, angiogenesis and lymphangiogenesis markers expression in uninvolved skin in psoriatic patients (N), early psoriasis lesions or pinpoints (PP) and psoriasis plaques (PSO). Methods Skin biopsies were taken in 17 patients in N and in PSO and/or PP. The mRNA steady-state level of angiogenesis and lymphangiogenesis markers was measured by RT-PCR. Immunohistochemistry was performed for von Willebrand factor, podoplanin, Ki-67 and VEGFR3. Blood (BV) and lymphatic (LV) vessels expansion was measured by computer-assisted morphometry. Results Clinical and epidermal aspects indicated that PP are intermediate between N and PSO. While total BV area was already increased in PP similarly to PSO as compared to N, LV area in PP was intermediate between N and PSO. Mean LV size was identical in N and PP and increased in PSO, mean BV size in PP being intermediate between N and PSO. VEGF-A 189 variant was increased in PP as compared to N and PSO. As compared to N, angiogenesis markers (VEGF-A isoforms, PlGF, VEGFR2, NRP-1), VEGF-C and NRP-2 were similarly increased in PP and PSO. Keratin 16 and the lymphangiogenesis markers (VEGFR3, prox-1) were intermediate in PP. Conclusion These data suggest that the expansion of lymphatic vessels occurs after blood vascular development in psoriasis. Expansion of BV in PP could be followed by vessel enlargement during progression to PSO, in parallel with a decreased VEGF-A 189/VEGF-A 121 balance in plaques [less ▲]Detailed reference viewed: 71 (11 ULg)
Preparation of cross-linked chitosan-based nanofibers as wound dressing
Aqil, Abdelhafid ; ; Tchemtchoua Tateu, Victor et al
Poster (2009, November 18)Detailed reference viewed: 56 (19 ULg)
New asthma biomarkers: lessons from murine models of acute and chronic asthma.
Di Valentin, Emmanuel ; ; Garbacki, Nancy et al
in American Journal of Physiology - Lung Cellular and Molecular Physiology (2009), 296(2), 185-97
Many patients suffering from asthma are not fully controlled by currently available treatments, and some of them display an airway remodeling leading to exaggerated lung function decline. The aim of the ... [more ▼]
Many patients suffering from asthma are not fully controlled by currently available treatments, and some of them display an airway remodeling leading to exaggerated lung function decline. The aim of the present study was to unveil new mediators in asthma to better understand pathophysiology and propose or validate new potential therapeutic targets. A mouse model of asthma mimicking acute or chronic asthma disease was used to select genes undergoing a modulation in both acute and chronic conditions. Mice were exposed to ovalbumin or PBS for 1, 5, and 10 wk [short-, intermediate-, and long-term model (ST, IT, and LT)], and gene expression in the lung was studied using an Affymetrix 430 2.0 genome-wide microarray and further confirmed by RT-PCR and immunohistochemistry for selected targets. We report that 598, 1,406, and 117 genes were upregulated and 490, 153, 321 downregulated at ST, IT, and LT, respectively. Genes related to mucous secretion displayed a progressively amplified expression during the allergen exposure protocol, whereas genes corresponding to growth and differentiation factors, matrix metalloproteinases, and collagens were mainly upregulated at IT. By contrast, genes related to cell division were upregulated at ST and IT and were downregulated at LT. In this study, besides confirming that Arg1, Slc26a4, Ear11, and Mmp12 genes are highly modulated throughout the asthma pathology, we show for the first time that Agr2, Scin, and Cd209e genes are overexpressed throughout the allergen exposure and might therefore be considered as suitable new potential targets for the treatment of asthma. [less ▲]Detailed reference viewed: 179 (37 ULg)
The CORALS project: simulated Cosmic Radiations and Alternative Splicing.
Lambert, Charles ; ; et al
Conference (2009)Detailed reference viewed: 12 (0 ULg)
Characterisation and evaluation of nanoparticles made of chitosan and timethylchitosan as siRNA carriers
Dehousse, Vincent ; Garbacki, Nancy ; Colige, Alain et al
in Proceedings of 2nd PharmSci Fair (2009)Detailed reference viewed: 35 (12 ULg)
Effects of mechanical stretch on human osteoblasts: role of the rho family GTPases in the mechanotransduction.
Neutelings, Thibaut ; ; Nusgens, Betty et al
Poster (2009)Detailed reference viewed: 27 (11 ULg)
Cold shock (25°C) and re-warming (37°C) affect cell phenotype: impac on space biology experiments.
Neutelings, Thibaut ; ; Nusgens, Betty et al
Conference (2009)Detailed reference viewed: 9 (1 ULg)
Role of the Rho family GTPases in the mechano-transduction and -reaction in human osteoblasts.
Lambert, Charles ; Neutelings, Thibaut ; et al
Poster (2009)Detailed reference viewed: 15 (0 ULg)
Development of a procedure to simultaneously isolate RNA, DNA, and proteins from characterizing cells invading or cultured on chitosan scaffolds.
Tchemtchoua Tateu, Victor ; ; Aqil, Abdelhafid et al
in Analytical Biochemistry (2009), 393(1), 145-7
For many years, chitosan and its derivatives have been considered to be promising biomaterials for tissue engineering and repair. However, information regarding their biological effect on cell phenotype ... [more ▼]
For many years, chitosan and its derivatives have been considered to be promising biomaterials for tissue engineering and repair. However, information regarding their biological effect on cell phenotype is usually limited to evaluation of cell proliferation and survival, overlooking proteomic and transcriptomic analysis. This is largely related to the lack of efficient and quantitative procedures for protein and nucleic acid purification from cells cultured on, or inside, chitosan scaffold. Here we describe an ultracentrifugation procedure enabling the simultaneous and quantitative recovery of high quality RNA, DNA and proteins from cells growing in close contact of biomaterial matrices containing chitosan. [less ▲]Detailed reference viewed: 111 (16 ULg)
Matrix metalloproteinase 12 silencing: A therapeutic approach to treat pathological lung tissue remodeling?
Garbacki, Nancy ; Di Valentin, Emmanuel ; Piette, Jacques et al
in Pulmonary Pharmacology & Therapeutics (2009), 22(4), 267-278
Among the large matrix metalloproteinases (MMPs) family, MMP-12, also referred to as macrophage elastase, plays a significant role in chronic pulmonary pathologies characterized by an intense tissue ... [more ▼]
Among the large matrix metalloproteinases (MMPs) family, MMP-12, also referred to as macrophage elastase, plays a significant role in chronic pulmonary pathologies characterized by an intense tissue remodeling such as asthma and COPD. This review will summarize knowledge about MMP-12 structure, functions and mechanisms of activation and regulation, including potential MMP-12 modulation by microRNA. As MMP-12 is involved in many tissue remodeling diseases, efforts have been made to develop specific synthetic inhibitors. However, at this time, very few chemical inhibitors have proved to be efficient and specific to a particular MMP. The relevance of silencing MMP-12 by RNA interference is highlighted. The specificity of this approach using siRNA or shRNA and the strategies to deliver these molecules in the lung are discussed. [less ▲]Detailed reference viewed: 105 (22 ULg)
Altered expression of angiogenesis and lymphangiogenesis markers in the uninvolved skin of plaque-type psoriasis
Henno, Audrey ; Blacher, Silvia ; Lambert, Charles et al
in British Journal of Dermatology (2009), 160(3), 581-90
Background Vascular alterations are significant events in the pathomechanism of psoriasis. A disorder in the mechanisms regulating skin angiogenesis and lymphangiogenesis could participate in the ... [more ▼]
Background Vascular alterations are significant events in the pathomechanism of psoriasis. A disorder in the mechanisms regulating skin angiogenesis and lymphangiogenesis could participate in the pathogenesis of the disease. Objectives To quantify differences in the expression of angiogenesis and lymphangiogenesis growth factors, receptors, coreceptors as well as their antagonists in the uninvolved skin of patients with psoriasis compared with the skin of nonpsoriatic volunteers. Methods Skin biopsies were collected from the involved skin of 13 patients with untreated plaque-type psoriasis, from their nonlesional skin at distance from the lesions and from the skin of 16 healthy volunteers. The mRNA steady-state level of keratins 10, 14 and 16, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), vimentin, collagen I and IV, proliferating cell nuclear antigen, the various splice variants of vascular endothelial growth factor, VEGF-A, VEGF-C and VEGF-D, their receptors VEGFR1, VEGFR2 and VEGFR3, neuropilin (NRP)-1 and its soluble forms, NRP-2, semaphorin 3A and prox-1, was measured by reverse transcription–polymerase chain reaction. Immunohistochemistry was performed for Ki-67, von Willebrand factor and D2-40. Blood and lymphatic vessel density, area and distance from epidermis were estimated by morphological analysis coupled to an original computer-assisted method of quantification. Results Skin from healthy volunteers and nonlesional skin from patients with psoriasis displayed similar histological, morphometric and proliferative features. However, a significant overexpression of VEGFR3, the VEGF-A isoform VEGF121, soluble 12 NRP-1 and GAPDH was observed in the nonlesional psoriatic skin as compared with that of normal volunteers. Conclusions These data point to significant differences in the blood and lymphatic vascular transcriptome between the clinically normal-appearing skin of patients with psoriasis and the skin of volunteers without psoriasis. [less ▲]Detailed reference viewed: 129 (54 ULg)