Gla-rich protein function as an anti-inflammatory agent in monocytes/macrophages: implications for calcification-related chronic inflammatory diseases

Calcification-related chronic inflammatory diseases are multifactorial pathological processes, involving a complex interplay between inflammation and calcification events in a positive feed-back loop driving disease progression. Gla-rich protein (GRP) is a vitamin K dependent protein (VKDP) shown to function as a calcification inhibitor in cardiovascular and articular tissues, and proposed as an anti-inflammatory agent in chondrocytes and synoviocytes, acting as a new crosstalk factor between these two interconnected events in osteoarthritis. However, a possible function of GRP in the immune system has never been studied. Here we focused our investigation in the involvement of GRP in the cell inflammatory response mechanisms, using a combination of freshly isolated human leucocytes and undifferentiated/differentiated THP-1 cell line. Our results demonstrate that VKDPs such as GRP and matrix gla protein (MGP) are synthesized and gamma-carboxylated in the majority of human immune system cells either involved in innate or adaptive immune responses. Stimulation of THP-1 monocytes/macrophages with LPS or hydroxyapatite (HA) up-regulated GRP expression, and treatments with GRP or GRP-coated basic calcium phosphate crystals resulted in the down-regulation of mediators of inflammation and inflammatory cytokines, independently of the protein gamma-carboxylation status. Moreover, overexpression of GRP in THP-1 cells rescued the inflammation induced by LPS and HA, by down-regulation of the proinflammatory cytokines TNF alpha, IL-1 beta and NFkB. Interestingly, GRP was detected at protein and mRNA levels in extracellular vesicles released by macrophages, which may act as vehicles for extracellular trafficking and release. Our data indicate GRP as an endogenous mediator of inflammatory responses acting as an anti-inflammatory agent in monocytes/macrophages. We propose that in a context of chronic inflammation and calcification-related pathologies, GRP might act as a novel molecular mediator linking inflammation and calcification events, with potential therapeutic application.Portuguese Science and Technology Foundation (FCT) [PTDC/SAU-ORG/117266/2010, PTDC/BIM-MEC/1168/2012, UID/Multi/ 04326/2013]; FCT fellowships [SFRH/BPD/70277/2010, SFRH/BD/111824/2015

Regional projection of winter frost risk on a legume crop due to warming in a temperate climate

International audiencePea (Pisum sativum L.) is an important annual legume crop grown in temperate regions for its high seed nitrogenconcentration and environmental benefits. In the recent climate warming, a subtle evolution of the winter cropfrost risk was observed: a paradoxical increase of frost stress events and a frost stress intensity decrease (Castel etal. 2017). Such results are questioning the future winter frost risk for peas. We assessed the winter frost damageevolution along 2006 to 2100 in Burgundy-Franche-Comté (a French region - western part of Europe). The approachis based on the combination of i) a dynamical downscaled climate data of two RCP trajectories (4.5 and 8.5) (Boulardet al. 2016) and ii) a winter frost stress model calibrated and validated for pea (using varieties with different frostresistance levels and acclimation rates) (Lecomte et al. 2003; Castel et al. 2017). Our results show that frost risk willnot disappear with warming climate (Fig. 1). Compared to the historical period (1980-2005), the frost risk for the peavariety with a frost resistance level of -13°C will increase along the near future period (2020-2050) for RCP 8.5: withan increase of both the median and the spread of the cumulative frost degree days (Fig. 1B). With a highest warmingalong the far future period (2070-2100) for RCP 8.5, the results show a significant decrease of the cumulative frostdegree days compared to the near future and the historical periods, but the frost risk will persist (Fig. 1B). It suggeststhat frost risk will significantly increase for an extended winter warming below + 2°C, while it will decrease whenthis threshold will be overpassed (Fig. 1). The figure 2 depicts the evolution of the two components of the froststress with warming: intensity and number of the frost stress events. The increase of the cumulative frost degreedays in the near future period (2020-2050) for RCP 8.5 is determined by the increase of frost stress events intensity(Fig. 2A). By contrast the number of frost stress events slightly decrease during this period (Fig. 2B). This resultdiffers from the past evolution of these components with the observed warming from 1961 to 2018 (Castel et al.2019) and suggests a change in the winter frost risk structure. For the end of the century (period 2070-2100) andfor the RCP 8.5, both intensity and number of the frost stress events will decrease (Fig. 2). Finally the projectionsshow a contrasted geography of the frost risk evolution. This geographic trend depends on the frost resistance leveland acclimation rate of the pea variety. Our results seem to confirm subtle evolutions of winter climate warmingdynamics revealed by the change in the pea crop frost risk structure. Moreover, this work provides leads for breedingand crop management techniques strategies for winter pea adaptation to climate change to avoid the detrimentaleffects of frost while taking advantage of the potential of this crop

Regional projection of winter frost risk on a legume crop due to warming in a temperate climate

International audiencePea (Pisum sativum L.) is an important annual legume crop grown in temperate regions for its high seed nitrogenconcentration and environmental benefits. In the recent climate warming, a subtle evolution of the winter cropfrost risk was observed: a paradoxical increase of frost stress events and a frost stress intensity decrease (Castel etal. 2017). Such results are questioning the future winter frost risk for peas. We assessed the winter frost damageevolution along 2006 to 2100 in Burgundy-Franche-Comté (a French region - western part of Europe). The approachis based on the combination of i) a dynamical downscaled climate data of two RCP trajectories (4.5 and 8.5) (Boulardet al. 2016) and ii) a winter frost stress model calibrated and validated for pea (using varieties with different frostresistance levels and acclimation rates) (Lecomte et al. 2003; Castel et al. 2017). Our results show that frost risk willnot disappear with warming climate (Fig. 1). Compared to the historical period (1980-2005), the frost risk for the peavariety with a frost resistance level of -13°C will increase along the near future period (2020-2050) for RCP 8.5: withan increase of both the median and the spread of the cumulative frost degree days (Fig. 1B). With a highest warmingalong the far future period (2070-2100) for RCP 8.5, the results show a significant decrease of the cumulative frostdegree days compared to the near future and the historical periods, but the frost risk will persist (Fig. 1B). It suggeststhat frost risk will significantly increase for an extended winter warming below + 2°C, while it will decrease whenthis threshold will be overpassed (Fig. 1). The figure 2 depicts the evolution of the two components of the froststress with warming: intensity and number of the frost stress events. The increase of the cumulative frost degreedays in the near future period (2020-2050) for RCP 8.5 is determined by the increase of frost stress events intensity(Fig. 2A). By contrast the number of frost stress events slightly decrease during this period (Fig. 2B). This resultdiffers from the past evolution of these components with the observed warming from 1961 to 2018 (Castel et al.2019) and suggests a change in the winter frost risk structure. For the end of the century (period 2070-2100) andfor the RCP 8.5, both intensity and number of the frost stress events will decrease (Fig. 2). Finally the projectionsshow a contrasted geography of the frost risk evolution. This geographic trend depends on the frost resistance leveland acclimation rate of the pea variety. Our results seem to confirm subtle evolutions of winter climate warmingdynamics revealed by the change in the pea crop frost risk structure. Moreover, this work provides leads for breedingand crop management techniques strategies for winter pea adaptation to climate change to avoid the detrimentaleffects of frost while taking advantage of the potential of this crop