SIRNA-Directed In Vivo Silencing of Androgen Receptor Inhibits the Growth of Castration-Resistant Prostate Carcinomas

BACKGROUND: Prostate carcinomas are initially dependent on androgens, and castration or androgen antagonists inhibit their growth. After some time though, tumors become resistant and recur with a poor prognosis. The majority of resistant tumors still expresses a functional androgen receptor (AR), frequently amplified or mutated. METHODOLOGY/PRINCIPAL FINDINGS: To test the hypothesis that AR is not only expressed, but is still a key therapeutic target in advanced carcinomas, we injected siRNA targeting AR into mice bearing exponentially growing castration-resistant tumors. Quantification of siRNA into tumors and mouse tissues demonstrated their efficient uptake. This uptake silenced AR in the prostate, testes and tumors. AR silencing in tumors strongly inhibited their growth, and importantly, also markedly repressed the VEGF production and angiogenesis. CONCLUSIONS/SIGNIFICANCE: Our results demonstrate that carcinomas resistant to hormonal manipulations still depend on the expression of the androgen receptor for their development in vivo. The siRNA-directed silencing of AR, which allows targeting overexpressed as well as mutated isoforms, triggers a strong antitumoral and antiangiogenic effect. siRNA-directed silencing of this key gene in advanced and resistant prostate tumors opens promising new therapeutic perspectives and tools

Evaluation of the Effect of a Single Intra-articular Injection of Allogeneic Neonatal Mesenchymal Stromal Cells Compared to Oral Non-Steroidal Anti-inflammatory Treatment on the Postoperative Musculoskeletal Status and Gait of Dogs over a 6-Month Period after Tibial Plateau Leveling Osteotomy: A Pilot Study

ObjectiveCompare the clinical and pressure walkway gait evolution of dogs after a tibial plateau leveling osteotomy (TPLO) for a cranial cruciate ligament rupture (CrCLR) and treatment with either a 1-month course of non-steroidal anti-inflammatory drugs (NSAIDs) or a single postoperative intra-articular (IA) injection of allogeneic neonatal mesenchymal stromal cells (MSCs).Study designProspective, double-blinded, randomized, controlled, monocentric clinical study.AnimalsSixteen client-owned dogs.Materials and methodsDogs with unilateral CrCLR confirmed by arthroscopy were included. Allogeneic neonatal canine MSCs were obtained from fetal adnexa retrieved after C-section performed on healthy pregnant bitches. The dogs were randomly allocated to either the “MSCs group,” receiving an IA injection of MSCs after TPLO, followed by placebo for 1 month, or the “NSAIDs group,” receiving IA equivalent volume of MSCs vehicle after TPLO, followed by oral NSAID for 1 month. One of the three blinded evaluators assessed the dogs in each group before and after surgery (1, 3, and 6 months). Clinical score and gait and bone healing process were assessed. The data were statistically compared between the two groups for pre- and postoperative evaluations.ResultsFourteen dogs (nine in the MSCs group, five in the NSAIDs group) completed the present study. No significant difference was observed between the groups preoperatively. No local or systemic adverse effect was observed after MSCs injection at any time point considered. At 1 month after surgery, bone healing scores were significantly higher in the MSCs group. At 1, 3, and 6 months after surgery, no significant difference was observed between the two groups for clinical scores and gait evaluation.ConclusionA single IA injection of allogeneic neonatal MSCs could be a safe and valuable postoperative alternative to NSAIDs for dogs requiring TPLO surgery, particularly for dogs intolerant to this class of drugs

The role of infectious disease trainees during the first wave of the COVID-19 pandemic: A national survey

International audienc

Experience abroad and participation in ESCMID educational activities: results from a survey among French infectious diseases specialists in training

International audienc

Mitochondrial AIF Loss Causes Metabolic Reprogramming, Caspase-Independent Cell Death Blockade, Embryonic Lethality, and Perinatal Hydrocephalus

International audienceObjectives: Apoptosis-Inducing Factor (AIF) is a protein involved in mitochondrial electron transport chain assembly/stability and in programmed cell death. The relevant role of this protein is underlined by the fact that mutations altering mitochondrial AIF properties result in acute pediatric mitochondriopathies and tumor metastasis. By generating an original AIF-deficient mouse strain, the present study sought to analyze, in a single paradigm, the cellular and developmental metabolic consequences of AIF loss and the subsequent oxidative phosphorylation (OXPHOS) dysfunction.Methods: We developed a novel AIF-deficient mouse strain and assessed, by molecular and cell biology approaches, the cellular, embryonic, and adult mice phenotypic alterations. Additionally, we carried out ex vivo assays with primary and immortalized AIF knockout mouse embryonic fibroblasts (MEFs) to establish the cell death characteristics and the metabolic adaptive responses provoked by the mitochondrial electron transport chain (ETC) breakdown.Results: AIF deficiency destabilized mitochondrial ETC and provoked supercomplex disorganization, mitochondrial transmembrane potential loss, and high generation of mitochondrial reactive oxygen species (ROS). AIF-/Y MEFs counterbalanced these OXPHOS alterations by mitochondrial network reorganization and a metabolic reprogramming towards anaerobic glycolysis illustrated by the AMPK phosphorylation at Thr172, the overexpression of the glucose assimilation transporter GLUT-4, the subsequent enhancement of glucose uptake, and the anaerobic lactate generation. A late phenotype was characterized by the activation of P53/P21-mediated senescence. Interestingly, about 2% of AIF-/Y MEFs diminished both mitochondrial mass and ROS levels and spontaneously proliferated. These cycling AIF-/Y MEFs were resistant to caspase-independent cell death inducers. The AIF-deficient mouse strain was embryonic lethal between E11.5 and E13.5 with energy loss, proliferation arrest, and increased apoptotic levels. Contrary to AIF-/Y MEFs, the AIF KO embryos were unable to reprogram their metabolism towards anaerobic glycolysis. Heterozygous AIF-/+ females displayed a progressive bone marrow, thymus, and spleen cellular loss. In addition, about 10% of AIF-/+ females developed perinatal hydrocephaly characterized by brain development impairment, meningeal fibrosis, and medullar hemorrhages; those mice died around 5 weeks of age. AIF-/+ with hydrocephaly exhibited loss of ciliated epithelium in the ependymal layer. This phenotype seemed triggered by the ROS excess. Accordingly, it was possible to diminish the occurrence of hydrocephalus AIF-/+ females by supplying dams and newborns with an antioxidant in drinking water.Conclusion: In a single knockout model and at three different levels (cell, embryo, and adult mice) we demonstrated that, by controlling the mitochondrial OXPHOS/metabolism, AIF is a key factor regulating cell differentiation and fate. Additionally, by shedding new light on the pathological consequences of mitochondrial OXPHOS dysfunction, our new findings pave the way for novel pharmacological strategies

Efficacy of tocilizumab in Takayasu arteritis: Multicenter retrospective study of 46 patients

To assess the efficacy of tocilizumab in patients with Takayasu arteritis (TA)

AIF loss deregulates hematopoiesis and reveals different adaptive metabolic responses in bone marrow cells and thymocytes

International audienceMitochondrial metabolism is a tightly regulated process that plays a central role throughout the lifespan of hematopoietic cells. Herein, we analyze the consequences of the mitochondrial oxidative phosphorylation (OXPHOS)/metabolism disorder associated with the cell-specific hematopoietic ablation of apoptosis-inducing factor (AIF). AIF-null (AIF-/Y ) mice developed pancytopenia that was associated with hypocellular bone marrow (BM) and thymus atrophy. Although myeloid cells were relatively spared, the B-cell and erythroid lineages were altered with increased frequencies of precursor B cells, pro-erythroblasts I, and basophilic erythroblasts II. T-cell populations were dramatically reduced with a thymopoiesis blockade at a double negative (DN) immature state, with DN1 accumulation and delayed DN2/DN3 and DN3/DN4 transitions. In BM cells, the OXPHOS/metabolism dysfunction provoked by the loss of AIF was counterbalanced by the augmentation of the mitochondrial biogenesis and a shift towards anaerobic glycolysis. Nevertheless, in a caspase-independent process, the resulting excess of reactive oxygen species compromised the viability of the hematopoietic stem cells (HSC) and progenitors. This led to the progressive exhaustion of the HSC pool, a reduced capacity of the BM progenitors to differentiate into colonies in methylcellulose assays, and the absence of cell-autonomous HSC repopulating potential in vivo. In contrast to BM cells, AIF-/Y thymocytes compensated for the OXPHOS breakdown by enhancing fatty acid β-oxidation. By over-expressing CPT1, ACADL and PDK4, three key enzymes facilitating fatty acid β-oxidation (e.g., palmitic acid assimilation), the AIF-/Y thymocytes retrieved the ATP levels of the AIF +/Y cells. As a consequence, it was possible to significantly reestablish AIF-/Y thymopoiesis in vivo by feeding the animals with a high-fat diet complemented with an antioxidant. Overall, our data reveal that the mitochondrial signals regulated by AIF are critical to hematopoietic decision-making. Emerging as a link between mitochondrial metabolism and hematopoietic cell fate, AIF-mediated OXPHOS regulation represents a target for the development of new immunomodulatory therapeutics

Factors Associated with Asthma Severity in Children: Data from the French COBRAPed Cohort

International audienc