TY - JOUR A1 - Lisowska, Justyna A1 - Rödel, Claudia Jasmin A1 - Manet, Sandra A1 - Miroshnikova, Yekaterina A. A1 - Boyault, Cyril A1 - Planus, Emmanuelle A1 - De Mets, Richard A1 - Lee, Hsiao-Hui A1 - Destaing, Olivier A1 - Mertani, Hichem A1 - Boulday, Gwenola A1 - Tournier-Lasserve, Elisabeth A1 - Balland, Martial A1 - Abdelilah-Seyfried, Salim A1 - Albiges-Rizo, Corinne A1 - Faurobert, Eva T1 - The CCM1-CCM2 complex controls complementary functions of ROCK1 and ROCK2 that are required for endothelial integrity JF - Journal of cell science N2 - Endothelial integrity relies on a mechanical crosstalk between intercellular and cell-matrix interactions. This crosstalk is compromised in hemorrhagic vascular lesions of patients carrying loss-of-function mutations in cerebral cavernous malformation (CCM) genes. RhoA/ROCK-dependent cytoskeletal remodeling is central to the disease, as it causes unbalanced cell adhesion towards increased cell-extracellular matrix adhesions and destabilized cell-cell junctions. This study reveals that CCM proteins directly orchestrate ROCK1 and ROCK2 complementary roles on the mechanics of the endothelium. CCM proteins act as a scaffold, promoting ROCK2 interactions with VE-cadherin and limiting ROCK1 kinase activity. Loss of CCM1 (also known as KRIT1) produces excessive ROCK1-dependent actin stress fibers and destabilizes intercellular junctions. Silencing of ROCK1 but not ROCK2 restores the adhesive and mechanical homeostasis of CCM1 and CCM2-depleted endothelial monolayers, and rescues the cardiovascular defects of ccm1 mutant zebrafish embryos. Conversely, knocking down Rock2 but not Rock1 in wild-type zebrafish embryos generates defects reminiscent of the ccm1 mutant phenotypes. Our study uncovers the role of the CCM1-CCM2 complex in controlling ROCK1 and ROCK2 to preserve endothelial integrity and drive heart morphogenesis. Moreover, it solely identifies the ROCK1 isoform as a potential therapeutic target for the CCM disease. KW - CCM KW - ROCK KW - Endothelial integrity KW - Mechanotransduction Y1 - 2018 U6 - https://doi.org/10.1242/jcs.216093 SN - 0021-9533 SN - 1477-9137 VL - 131 IS - 15 PB - Company biologists LTD CY - Cambridge ER - TY - JOUR A1 - Otten, Cecile A1 - Knox, Jessica A1 - Boulday, Gwenola A1 - Eymery, Mathias A1 - Haniszewski, Marta A1 - Neuenschwander, Martin A1 - Radetzki, Silke A1 - Vogt, Ingo A1 - Haehn, Kristina A1 - De Luca, Coralie A1 - Cardoso, Cecile A1 - Hamad, Sabri A1 - Igual Gil, Carla A1 - Roy, Peter A1 - Albiges-Rizo, Corinne A1 - Faurobert, Eva A1 - von Kries, Jens P. A1 - Campillos, Monica A1 - Tournier-Lasserve, Elisabeth A1 - Derry, William Brent A1 - Abdelilah-Seyfried, Salim T1 - Systematic pharmacological screens uncover novel pathways involved in cerebral cavernous malformations JF - EMBO molecular medicine N2 - Cerebral cavernous malformations (CCMs) are vascular lesions in the central nervous system causing strokes and seizures which currently can only be treated through neurosurgery. The disease arises through changes in the regulatory networks of endothelial cells that must be comprehensively understood to develop alternative, non-invasive pharmacological therapies. Here, we present the results of several unbiased small-molecule suppression screens in which we applied a total of 5,268 unique substances to CCM mutant worm, zebrafish, mouse, or human endothelial cells. We used a systems biology-based target prediction tool to integrate the results with the whole-transcriptome profile of zebrafish CCM2 mutants, revealing signaling pathways relevant to the disease and potential targets for small-molecule-based therapies. We found indirubin-3-monoxime to alleviate the lesion burden in murine preclinical models of CCM2 and CCM3 and suppress the loss-of-CCM phenotypes in human endothelial cells. Our multi-organism-based approach reveals new components of the CCM regulatory network and foreshadows novel small-molecule-based therapeutic applications for suppressing this devastating disease in patients. KW - angiogenesis KW - CCM KW - ERK5 KW - indirubin-3-monoxime KW - KLF2 Y1 - 2018 U6 - https://doi.org/10.15252/emmm.201809155 SN - 1757-4676 SN - 1757-4684 VL - 10 IS - 10 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Lachmann, Sabrina C. A1 - Maberly, Stephen C. A1 - Spijkerman, Elly T1 - Species-specific influence of P-i-status on inorganic carbon acquisition in microalgae (Chlorophyceae) JF - Botany N2 - Inorganic phosphorus (P-i) is often the primary limiting nutrient in freshwater ecosystems. Since P(i-)limitation affects energy transduction, and inorganic carbon (C-i) acquisition can be energy demanding, C(i-)acquisition strategies were compared in four species of green algae grown under P-i-replete and P-i-limited conditions predominantly at low and partly at high CO2. Although P-i-limitation was evident by the 10-fold higher cellular C:P ratio and enhanced phosphatase activity, it only decreased C-i-acquisition to a small extent. Nonetheless, the effects of Pi-limitation on both CO2 and HCO3- acquisition were demonstrated. Decreased CO2 acquisition under conditions of Pi limitation was mainly visible in the maximum uptake rate (V-max) and, for the neutrophile Scenedesmus vacuolatus, in the affinity for CO2 acquisition. Discrimination against C-13 was higher under P-i-limited, high CO2 conditions, compared with P-i-replete, highCO(2) conditions, in Chlamydomonas acidophila and S. vacuolatus. In the pH-drift experiments, HCO3- acquisition was reduced in P-i-limited C. reinhardtii. In general, energy demanding bicarbonate uptake was indicated by the less strong discrimination against (13)Cunder lowCO(2) conditions in the neutrophiles (HCO3- users), separating them from the acidophilic or acidotolerant species (CO2 users). The high variability of the influence of Pi supply among different green algal species is linked to their species-specific C(i-)acquisition strategies. KW - CCM KW - Chlamydomonas KW - inorganic carbon uptake kinetics KW - inorganic phosphorus limitation KW - stable carbon isotope discrimination Y1 - 2017 U6 - https://doi.org/10.1139/cjb-2017-0082 SN - 1916-2790 SN - 1916-2804 VL - 95 SP - 943 EP - 952 PB - NRC Research Press CY - Ottawa ER - TY - JOUR A1 - Lachmann, Sabrina C. A1 - Maberly, Stephen C. A1 - Spijkerman, Elly T1 - ECOPHYSIOLOGY MATTERS: LINKING INORGANIC CARBON ACQUISITION TO ECOLOGICAL PREFERENCE IN FOUR SPECIES OF MICROALGAE (CHLOROPHYCEAE) JF - Journal of phycology N2 - The effect of CO2 supply is likely to play an important role in algal ecology. Since inorganic carbon (C-i) acquisition strategies are very diverse among microalgae and C-i availability varies greatly within and among habitats, we hypothesized that C-i acquisition depends on the pH of their preferred natural environment (adaptation) and that the efficiency of C-i uptake is affected by CO2 availability (acclimation). To test this, four species of green algae originating from different habitats were studied. The pH-drift and C-i uptake kinetic experiments were used to characterize C-i acquisition strategies and their ability to acclimate to high and low CO2 conditions and high and low pH was evaluated. Results from pH drift experiments revealed that the acidophile and acidotolerant Chlamydomonas species were mainly restricted to CO2, whereas the two neutrophiles were efficient bicarbonate users. CO2 compensation points in low CO2-acclimated cultures ranged between 0.6 and 1.4 mu M CO2 and acclimation to different culture pH and CO2 conditions suggested that CO2 concentrating mechanisms were present in most species. High CO2 acclimated cultures adapted rapidly to low CO2 condition during pH-drifts. C-i uptake kinetics at different pH values showed that the affinity for C-i was largely influenced by external pH, being highest under conditions where CO2 dominated the C-i pool. In conclusion, C-i acquisition was highly variable among four species of green algae and linked to growth pH preference, suggesting that there is a connection between C-i acquisition and ecological distribution. KW - acidophile KW - carbon acquisition KW - CCM KW - Chlamydomonas KW - Chlorella KW - CO2 supply KW - extremophile KW - inorganic carbon uptake kinetics KW - pH-drift KW - Scenedesmus Y1 - 2016 U6 - https://doi.org/10.1111/jpy.12462 SN - 0022-3646 SN - 1529-8817 VL - 52 SP - 1051 EP - 1063 PB - Wiley-Blackwell CY - Hoboken ER -