Vestigial like gene family expression in Xenopus: common and divergent features with other vertebrates

International audienceThe Drosophila Vestigial and Scalloped proteins form heterodimers that control wing development and are involved in muscle differentiation. Four vestigial like genes have been described in mammals. Similar to the Drosophila vestigial gene, they encode a short conserved domain (TONDU) required for interaction with the mammalian paralogues of Drosophila Scal- loped (i.e., TEAD proteins). We previously identified two TEAD genes in Xenopus laevis and we report here the expression of four distinct vestigial like genes in Xenopus (vgll1-4) that represent amphibian orthologs of the mammalian vestigial like genes. Vgll1 has a unique expression pattern which is restricted to epidermal cells, both in the embryo and in the adult. Vgll2 is expressed in the skeletal muscle lineage downstream of myogenic factors and in the embryonic brain similar to the avian and mammalian orthologues. Vgll3 expression is transient, identifies embryonic hindbrain rhombomere 2, and is negatively regulated by en2, but not by egr2. Vgll4 is mainly expressed in anterior neural structures. In summary, the four Xenopus vgll genes have unique/ complex expression profiles and they are differently expressed during embryogenesis. Moreover, these amphibian vestigial like genes display distinct responses to the major signaling pathways (i.e., activin, FGF or BMP) that orchestrate pattern-formation during early development

Hijacking of internal calcium dynamics by intracellularly residing viral rhodopsins

Rhodopsins are ubiquitous light-driven membrane proteins with diverse functions, including ion transport. Widely distributed, they are also coded in the genomes of giant viruses infecting phytoplankton where their function is not settled. Here, we examine the properties of OLPVR1 (Organic Lake Phycodnavirus Rhodopsin) and two other type 1 viral channelrhodopsins (VCR1s), and demonstrate that VCR1s accumulate exclusively intracellularly, and, upon illumination, induce calcium release from intracellular IP3-dependent stores. In vivo, this light-induced calcium release is sufficient to remote control muscle contraction in VCR1-expressing tadpoles. VCR1s natively confer light-induced Ca2+ release, suggesting a distinct mechanism for reshaping the response to light of virus-infected algae. The ability of VCR1s to photorelease calcium without altering plasma membrane electrical properties marks them as potential precursors for optogenetics tools, with potential applications in basic research and medicine

LIM Homeobox-2 Suppresses Hallmarks of Adult and Pediatric Liver Cancers by Inactivating MAPK/ERK and Wnt/Beta-Catenin Pathways

&lt;b&gt;&lt;i&gt;Introduction:&lt;/i&gt;&lt;/b&gt; Hepatocellular carcinoma and hepatoblastoma are two liver cancers characterized by gene deregulations, chromosomal rearrangements, and mutations in Wnt/beta-catenin (Wnt) pathway-related genes. LHX2, a transcriptional factor member of the LIM homeobox gene family, has important functions in embryogenesis and liver development. LHX2 is oncogenic in many solid tumors and leukemia, but its role in liver cancer is unknown. &lt;b&gt;&lt;i&gt;Methods:&lt;/i&gt;&lt;/b&gt; We analyzed the expression of &lt;i&gt;LHX2&lt;/i&gt; in hepatocellular carcinoma and hepatoblastoma samples using various transcriptomic datasets and biological samples. The role of LHX2 was studied using lentiviral transduction, in vitro cell-based assays (growth, migration, senescence, and apoptosis), molecular approaches (phosphokinase arrays and RNA-seq), bioinformatics, and two in vivo models in chicken and &lt;i&gt;Xenopus&lt;/i&gt; embryos. &lt;b&gt;&lt;i&gt;Results:&lt;/i&gt;&lt;/b&gt; We found a strong connection between LHX2 downregulation and Wnt activation in these two liver cancers. In hepatoblastoma, LHX2 downregulation correlated with multiple poor outcome parameters including higher patient age, intermediate- and high-risk tumors, and low patient survival. Forced expression of LHX2 reduced the proliferation, migration, and survival of liver cancer cells in vitro through the inactivation of MAPK/ERK and Wnt signals. In vivo, LHX2 impeded the development of tumors in chick embryos and repressed the Wnt pathway in &lt;i&gt;Xenopus&lt;/i&gt; embryos. RNA-sequencing data and bioinformatic analyses confirmed the deregulation of many biological functions and molecular processes associated with cell migration, cell survival, and liver carcinogenesis in LHX2-expressing hepatoma cells. At a mechanistic level, LHX2 mediated the disassembling of beta-catenin/T-cell factor 4 complex and induced expression of multiple inhibitors of Wnt (e.g., TLE/Groucho) and MAPK/ERK (e.g., DUSPs) pathways. &lt;b&gt;&lt;i&gt;Conclusion:&lt;/i&gt;&lt;/b&gt; Collectively, our findings demonstrate a tumor suppressive function of LHX2 in adult and pediatric liver cancers. </jats:p

LIM homeobox-2 suppresses hallmarks of adult and pediatric liver cancers by inactivating MAPK/ERK and Wnt/beta-catenin pathways

International audienceIntroduction: Hepatocellular carcinoma and hepatoblastoma are two liver cancers characterized by gene deregulations, chromosomal rearrangements, and mutations in Wnt/beta-catenin (Wnt) pathway-related genes. LHX2, a transcriptional factor member of the LIM homeobox gene family, has important functions in embryogenesis and liver development. LHX2 is oncogenic in many solid tumors and leukemia but its role in liver cancer is unknown. Methods: We analyzed the expression of LHX2 in hepatocellular carcinoma and hepatoblastoma samples using various transcriptomic datasets and biological samples. The role of LHX2 was studied using lentiviral transduction, in vitro cell-based assays (growth, migration, senescence, apoptosis), molecular approaches (phospho-kinase arrays, RNA-seq), bioinformatics and two in vivo models in chicken and Xenopus embryos. Results: We found a strong connection between LHX2 down-regulation and Wnt activation in these two liver cancers. In hepatoblastoma, LHX2 downregulation correlated with multiple poor outcome parameters including higher patient age, intermediate- and high-risk tumors and low patients’ survival. Forced expression of LHX2 reduced the proliferation, migration and survival of hepatoma cells in vitro through the inactivation of MAPK/ERK and Wnt signals. In vivo, LHX2 impeded the development of tumors in chick embryos and repressed the Wnt pathway in Xenopus embryos. RNA-sequencing data and bioinformatic analyses confirmed the deregulation of many biological functions and molecular processes associated with cell migration, cell survival and liver carcinogenesis in LHX2-expressing hepatoma cells. At a mechanistic level, LHX2 mediated the disassembling of beta-catenin/T-cell factor 4 complex and induced expression of multiple inhibitors of Wnt (e.g. TLE/Groucho) and MAPK/ERK (e.g. DUSPs) pathways. Conclusion: Collectively, our findings demonstrate a tumor suppressive function of LHX2 in adult and pediatric liver cancers

Hydrocortisone plus fludrocortisone for community acquired pneumonia-related septic shock: a subgroup analysis of the APROCCHSS phase 3 randomised trial

International audienceBackground: Glucocorticoids probably improve outcomes in patients hospitalised for community acquired pneumonia (CAP). In this a priori planned exploratory subgroup analysis of the phase 3 randomised controlled Activated Protein C and Corticosteroids for Human Septic Shock (APROCCHSS) trial, we aimed to investigate responses to hydrocortisone plus fludrocortisone between CAP and non-CAP related septic shock.Methods: APROCCHSS was a randomised controlled trial that investigated the effects of hydrocortisone plus fludrocortisone, drotrecogin-alfa (activated), or both on mortality in septic shock in a two-by-two factorial design; after drotrecogin-alfa was withdrawn on October 2011, from the market, the trial continued on two parallel groups. It was conducted in 34 centres in France. In this subgroup study, patients with CAP were a preselected subgroup for an exploratory secondary analysis of the APROCCHSS trial of hydrocortisone plus fludrocortisone in septic shock. Adults with septic shock were randomised 1:1 to receive, in a double-blind manner, a 7-day treatment with daily administration of intravenous hydrocortisone 50 mg bolus every 6h and a tablet of 50 μg of fludrocortisone via the nasogastric tube, or their placebos. The primary outcome was 90-day all-cause mortality. Secondary outcomes included all-cause mortality at intensive care unit (ICU) and hospital discharge, 28-day and 180-day mortality, the number of days alive and free of vasopressors, mechanical ventilation, or organ failure, and ICU and hospital free-days to 90-days. Analysis was done in the intention-to-treat population. The trial was registered at ClinicalTrials.gov (NCT00625209).Findings: Of 1241 patients included in the APROCCHSS trial, CAP could not be ruled in or out in 31 patients, 562 had a diagnosis of CAP (279 in the placebo group and 283 in the corticosteroid group), and 648 patients did not have CAP (329 in the placebo group and 319 in the corticosteroid group). In patients with CAP, there were 109 (39%) deaths of 283 patients at day 90 with hydrocortisone plus fludrocortisone and 143 (51%) of 279 patients receiving placebo (odds ratio [OR] 0·60, 95% CI 0·43-0·83). In patients without CAP, there were 148 (46%) deaths of 319 patients at day 90 in the hydrocortisone and fludrocortisone group and 157 (48%) of 329 patients in the placebo group (OR 0·95, 95% CI 0·70-1·29). There was significant heterogeneity in corticosteroid effects on 90-day mortality across subgroups with CAP and without CAP (p=0·046 for both multiplicative and additive interaction tests; moderate credibility). Of 1241 patients included in the APROCCHSS trial, 648 (52%) had ARDS (328 in the placebo group and 320 in the corticosteroid group). There were 155 (48%) deaths of 320 patients at day 90 in the corticosteroid group and 186 (57%) of 328 patients in the placebo group. The OR for death at day 90 was 0·72 (95% CI 0·53-0·98) in patients with ARDS and 0·85 (0·61-1·20) in patients without ARDS (p=0·45 for multiplicative interaction and p=0·42 for additive interaction). The OR for observing at least one serious adverse event (corticosteroid group vs placebo) within 180 days post randomisation was 0·64 (95% CI 0·46-0·89) in the CAP subgroup and 1·02 (0·75-1·39) in the non-CAP subgroup (p=0·044 for multiplicative interaction and p=0·042 for additive interaction).Interpretation: In a pre-specified subgroup analysis of the APROCCHSS trial of patients with CAP and septic shock, hydrocortisone plus fludrocortisone reduced mortality as compared with placebo. Although a large proportion of patients with CAP also met criteria for ARDS, the subgroup analysis was underpowered to fully discriminate between ARDS and CAP modifying effects on mortality reduction with corticosteroids. There was no evidence of a significant treatment effect of corticosteroids in the non-CAP subgroup.Funding: Programme Hospitalier de Recherche Clinique of the French Ministry of Health, by Programme d'Investissements d'Avenir, France 2030, and IAHU-ANR-0004