Platelet-derived growth factor negatively regulates the insulin-like growth factor signaling pathway through the coordinated action of phosphatidylinositol 3-kinase and protein kinase C beta I

AbstractWe recently described that epidermal and fibroblast growth factors (EGF and FGF) regulate the IGF-I signaling pathway at the level of IRS-1 through the cooperative action of two independent signaling pathways; one dependent on phosphatidylinositol 3-kinase (PI 3-kinase) and the other on protein kinase D1 (PKD1) (Karam et al. [22]). To determine whether this mechanism could be generalized to another tyrosine kinase receptor-dependent growth factor, the effect of platelet-derived growth factor (PDGF) on the IGF-I signaling pathway was studied. PDGF inhibited IGF-I-stimulated IRS-1 tyrosine phosphorylation and subsequent IGF-I-induced PI 3-kinase activity, and stimulated IRS-1 serine 307 phosphorylation. These effects were mediated through a PI 3-kinase-dependent but extracellular signal-regulated kinase (ERK)-independent signaling pathway. However, PDGF-induced IRS-1 serine 307 phosphorylation was not sufficient per se to inhibit the IGF-I signaling but required another independent pathway. Noteworthy, although acutely stimulated by PDGF, and contrary to what we previously described (Karam et al. [22]), PKD1 did not associate with IRS-1and did not inhibit the IGF-I signaling in response to PDGF. However, we identified PKCβI as a new regulatory partner of PI 3-kinase for PDGF-induced inhibition of the IGF-I signaling pathway. Therefore, our results reinforce the idea that a coordinated action of two independent pathways seems absolutely necessary to negatively regulate IRS-1. Moreover, they also demonstrated that, depending of the cross-talk considered, subtle and specific regulatory mechanisms occur at the level of IRS-1 and that a unique regulatory model is not conceivable

Environmental characterisation of retification process by-products (liquid and gaseous wastes)

6th International Symposium “Environment and Wood Preservation” Cannes-Mandelieu, France 7-8 February 2005 14 pagesIn order to reduce environmental risks during the service life of the treated wood and to find new alternative developments on the durability of wood, some research and technology development have been made on thermal treatment. The retification process is one of these processes. The retification process induces chemical modification of the lignin and cellulosic components and modifies the intrinsic properties of wood : efficient increases the durability against fungi and insects, increases of the dimensional stability, decrease of the mechanical properties. The interest of this process is to reduce the environmental impact during the service life. In order to confirm the high interest of this process for the reduction of the environmental impact, an environmental characterisation of wastes on pilot plant have been carried out. Chemical analysis on gaseous and liquid effluents have been performed. An energetic assessment has been realised. The results indicate the high interest of this process in terms of possible biodegradable wastes and chemical valorisation interest, interest on energetic consumption in comparison with other wood processing treatment, interest on using retification treated wood in flooring according to indoor air quality requirements

Water Deficit-Responsive QTLs for Cell Wall Degradability and Composition in Maize at Silage Stage

The use of lignocellulosic biomass for animal feed or biorefinery requires the optimization of its degradability. Moreover, biomass crops need to be better adapted to the changing climate and in particular to periods of drought. Although the negative impact of water deficit on biomass yield has often been mentioned, its impact on biomass quality has only been recently reported in a few species. In the present study, we combined the mapping power of a maize recombinant inbred line population with robust near infrared spectroscopy predictive equations to track the response to water deficit of traits associated with biomass quality. The population was cultivated under two contrasted water regimes over 3 consecutive years in the south of France and harvested at silage stage. We showed that cell wall degradability and β-O-4-linked H lignin subunits were increased in response to water deficit, while lignin and p-coumaric acid contents were reduced. A mixed linear model was fitted to map quantitative trait loci (QTLs) for agronomical and cell wall-related traits. These QTLs were categorized as “constitutive” (QTL with an effect whatever the irrigation condition) or “responsive” (QTL involved in the response to water deficit) QTLs. Fifteen clusters of QTLs encompassed more than two third of the 213 constitutive QTLs and 13 clusters encompassed more than 60% of the 149 responsive QTLs. Interestingly, we showed that only half of the responsive QTLs co-localized with constitutive and yield QTLs, suggesting that specific genetic factors support biomass quality response to water deficit. Overall, our results demonstrate that water deficit favors cell wall degradability and that breeding of varieties that reconcile improved drought-tolerance and biomass degradability is possible

No wind, no wood – using tree biomechanics to better understand forest growth and vulnerability to strong winds

La biomécanique étudie les réactions et adaptations des êtres vivants à leur environnement mécanique, par exemple aux oscillations et forces exercées par le vent. Au-delà des théories anciennes de la sécurité mécanique constante, la mécanobiologie a récemment formalisé les signaux mécaniques, la perception des cellules vivantes et les réponses de croissance. Ces mécanismes physiologiques font que l’arbre ne forme vraiment du bois, tissu de soutien, que lorsqu’il est mécaniquement stimulé. La croissance est contrôlée par les déformations mécaniques perçues, qui deviennent alors pour l’arbre de bons indicateurs de sécurité. Pour appliquer ces connaissances aux forêts, le projet ANR FOR-WIND a l’ambition de développer une mécanobiologie adaptée aux temps longs et aux conditions naturelles complexes. L’enjeu est de concevoir les pratiques d’aménagement avec de nouveaux indicateurs de vulnérabilité aux vents forts, qui raisonnent l’effet du changement climatique, de la structure du paysage, de la sylviculture ou de l’amélioration génétique au travers des processus clés mais négligés d’endurcissement des arbres aux vents usuels.Biomechanics studies how living bodies react and adapt to their mechanical environment, especially wind sways and loads. Going beyond the old theories of optimal design and constant safety, recent advances in mechanobiology have formalized mechanical signalling, living cell perception and growth responses. Due to these physiological processes, trees form wood as a support tissue only under mechanical stimulation. Growth is controlled by perceived mechanical strains, which are indeed relevant safety indicators. To apply this knowledge to forests, the aim of the ANR FOR-WIND research project is to build a mechanobiological framework suited to long periods of time and complex natural conditions. The overall objective is to introduce new indicators into forest management practices, based on the key processes of wind acclimatisation and hardening of trees to analyse how climate change, landscape structure, silviculture or tree breeding impact forest vulnerability to strong winds

A Multi-Actor Partnership and a Multidisciplinary Approach to Innovate Forest Planting Practices

La plantation forestière est un outil important pour l’adaptation des forêts aux changements globaux. Les échecs parfois récurrents dans certains contextes, les coûts associés à la plantation, la pénibilité du travail pour les ouvriers forestiers ainsi que les impacts environnementaux parfois négatifs sont autant de facteurs qui freinent le recours à la plantation et peuvent ainsi limiter la capacité d’adaptation des forêts. Un ensemble de travaux ont été menés pour répondre aux besoins en innovation technique sur les méthodes de plantation exprimés par les praticiens. Ces travaux portent sur le processus d’innovation en sylviculture et sur l’amélioration technique des méthodes de plantation. L’analyse du processus d’innovation indique une faiblesse des réseaux sociotechniques associée à un mauvais partage des connaissances entre acteurs, et une réticence à l’investissement dans du nouveau matériel, dans un contexte économique perçu comme incertain. Ces observations suggèrent qu’un des leviers possibles serait une meilleure mise en réseau des acteurs, à travers différents liens fonctionnels: partage d’information, échanges de services, construction de partenariats économiques. Des exemples de méthodes innovantes pour réaliser chacune des différentes étapes de l’itinéraire de plantation (préparation du site, plantation, entretiens), répondant aux besoins d’innovation technique exprimés par les praticiens, sont ensuite présentés.Forest plantation is a major tool to adapt forest ecosystems to global change. Plantation failure that recurrently occur in some contexts, associated financial costs, the hard and repetitive nature of tree planting, and potential negative environmental impacts of forest plantation strongly reduce the use of plantation to regenerate forest stands. A series of studies was conducted to address the need for forest practitioners to innovate. The studies focus on the innovation process in silviculture, and on the technical improvement of plantation methods. The analysis of the innovation process highlights the weaknesses of the sociotechnical networks, in relationship with poor knowledge exchange practices, and strong reluctance to invest in new equipment in an uncertain future context. Developing stronger sociotechnical networks, based on information, service and financial flows, is a key to the development and diffusion of new silvicultural methods. Finally, examples of new methods, to execute the successive steps of forest planting (site preparation, planting, cleaning operations), addressing the expectations of forest practitioners, are presented

Resource management planning and ecological intensification to address climate challenges in French forestry

International audienceThe talk illustrates two aspects of reshaping forest management in order to tackle the pressures of climate change and address the combined challenges of adaptation, mitigation and ecosystem service regulation : (i) resource management planning has to put more emphasis on coordinated, multi-scale procedures, diversification, tree planting, ecosystem resilience support, investment selection, logistics and information management ; (ii) ecological intensification, in the case of temperate forests, may be viewed as a more efficient use of natural and human-induced cycles of matter, energy and information in ecosystems as well as in the emerging bioeconomy. Through questioning how to implement management change in a context of uncertainty, stronger constraints and higher and more diverse expectations, ecological intensification for forests cannot be confused with naturalness, and contradicts European concepts of « close-to-nature forestry » in many regards. It is more productive to see ecological intensification as investing to improve the monitoring of different critical fluxes and the efficiency of their use (carbon, water, nutrients, products-coproducts-byproducts, species-genetic resources, plants, fertilizers, machines, information, etc…). For European foresters, making a clear distinction between ecology and imitation of nature will be a fundamental challenge to successfully achieve the present transitio

Resource management planning and ecological intensification to address climate challenges in French forestry

The talk illustrates two aspects of reshaping forest management in order to tackle the pressures of climate change and address the combined challenges of adaptation, mitigation and ecosystem service regulation : (i) resource management planning has to put more emphasis on coordinated, multi-scale procedures, diversification, tree planting, ecosystem resilience support, investment selection, logistics and information management ; (ii) ecological intensification, in the case of temperate forests, may be viewed as a more efficient use of natural and human-induced cycles of matter, energy and information in ecosystems as well as in the emerging bioeconomy. Through questioning how to implement management change in a context of uncertainty, stronger constraints and higher and more diverse expectations, ecological intensification for forests cannot be confused with naturalness, and contradicts European concepts of « close-to-nature forestry » in many regards. It is more productive to see ecological intensification as investing to improve the monitoring of different critical fluxes and the efficiency of their use (carbon, water, nutrients, products-coproducts-byproducts, species-genetic resources, plants, fertilizers, machines, information, etc…). For European foresters, making a clear distinction between ecology and imitation of nature will be a fundamental challenge to successfully achieve the present transitio

Protein Kinase D1 (PKD1) Is a New Functional Non-Genomic Target of Bisphenol A in Breast Cancer Cells

International audienceExposure to bisphenol A (BPA), one of the most widespread endocrine disruptors present in our environment, has been associated with the recent increased prevalence and severity of several diseases such as diabetes, obesity, autism, reproductive and neurological defects, oral diseases, and cancers such as breast tumors. BPA is suspected to act through genomic and non-genomic pathways. However, its precise molecular mechanisms are still largely unknown. Our goal was to identify and characterize a new molecular target of BPA in breast cancer cells in order to better understand how this compound may affect breast tumor growth and development. By using in vitro (MCF-7, T47D, Hs578t, and MDA-MB231 cell lines) and in vivo models, we demonstrated that PKD1 is a functional non-genomic target of BPA. PKD1 specifically mediates BPAinduced cell proliferation, clonogenicity, and anchorage-independent growth of breast tumor cells. Additionally, low-doses of BPA (≤10 −8 M) induced the phosphorylation of PKD1, a key signature of its activation state. Moreover, PKD1 overexpression increased the growth of BPA-exposed breast tumor xenografts in vivo in athymic female Swiss nude (Foxn1 nu/nu) mice. These findings further our understanding of the molecular mechanisms of BPA. By defining PKD1 as a functional target of BPA in breast cancer cell proliferation and tumor development, they provide new insights into the pathogenesis related to the exposure to BPA and other endocrine disruptors acting similarly