Ganetespib limits ciliation and cystogenesis in autosomal-dominant polycystic kidney disease (ADPKD)

© 2018 FASEB. Autosomal-dominant polycystic kidney disease (ADPKD) is associated with progressive formation of renal cysts, kidney enlargement, hypertension, and typically end-stage renal disease. In ADPKD, inherited mutations disrupt functionofthe polycystins (encoded byPKD1 and PKD2), thus causing loss of a cyst-repressive signal emanating from the renal cilium. Genetic studies have suggested ciliary maintenance is essential for ADPKD pathogenesis. Heat shock protein 90 (HSP90) clients include multiple proteins linked to ciliary maintenance. We determined that ganetespib, a clinical HSP90 inhibitor, inhibited proteasomal repression of NEK8 and the Aurora-A activator trichoplein, rapidly activating Aurora-A kinase and causing ciliary loss in vitro. Using conditional mouse models for ADPKD, we performed long-term (10 or 50 wk) dosing experiments that demonstrated HSP90 inhibition caused durable in vivo loss of cilia, controlled cystic growth, and ameliorated symptoms induced by loss of Pkd1 or Pkd2.Ganetespib efficacy was not increased by combination with 2-deoxy-D-glucose, aglycolysis inhibitor showing some promise for ADPKD. These studies identify a new biologic activity for HSP90 and support a cilia-based mechanism for cyst repression

PLASMA MEMBRANE REDOX SYSTEM IN THE ERYTHROCYTES OF ROWERS: PILOT STUDY

Background: The oxidative stress results from a change in the physiological balance between oxidant and antioxidant species. The purpose of this study is twofold: first, to investigate the effects of long-term training in sports with high energy requirements on the redox balance which exists between the plasma vs. the erythrocytes; second, to study the activity of the PMRS (Plasma Membrane Redox System), which is a compensatory mechanism of cellular redox homeostasis, in the rowers’ erythrocytes in order to determine the rowers’ counteraction to oxidative stress. Methods: Venous blood samples was collected from rowers and control group; then FRAP (Ferric Reducing Activity Power) method has been used to determine the antioxidant capabilities both in the plasma and in the erythrocytes of 22 rowers vs. 26 sedentary subjects. For the same groups of subjects, the PMRS in erythrocytes has been also evaluated. Results: The plasmatic antioxidant activity was 21% lower in the group of rowers compared to the sedentary group (p = 0,02). In contrast, no significant differences were found in the reducing activity of the erythrocytes; however the erythrocytes of the rowers have shown values of the PMRS 35% higher than the untrained group (p < 0.0001). Conclusions: Rowing induces a significant oxidative stress in the plasma corresponding to the high intensity training, while this effect lacks in erythrocytes. At the same time an increased quantity of the PMRS has been observed in the erythrocytes. In conclusion, in well trained athletes this not lead to established an oxidative stress condition because long-term training adaptatively improves the efficiency of the antioxidant syste

Effective strategies for promoting physical activity through the use of digital media among school-age children: A systematic review

Digital media are widespread among school-age children, and their incorrect use may lead to an increase in sedentary levels and the consequences associated with it. There are still few studies that have investigated whether physical activity levels could be increased through their use. The aim of this study was to systematically review the scientific literature in order to identify whether digital strategies and technologies are capable of increasing the level of physical activity. A literature search was performed using the following databases: Pubmed, Scopus, and Web of Science. The main outcomes evaluated the increase in physical activity levels, the number of steps, and the reduction of sedentary behaviors. Two trained researchers independently assessed eligible studies against eligibility criteria, extracted data, and assessed the risk of bias. The Downs and Black checklist was used to assess the quality of the included studies. A total of 15 studies (1122 children) were included in this systematic review, with a mean age of 8.45 ± 0.70 years. Quality assessment of the studies observed a “moderate quality” of the included records. The results of this systematic review highlight that digital media can be applied as a way to improve the levels of physical activity in children to contrast a sedentary lifestyle. The main limitations of the study are the heterogeneity within the exercise protocols and the paucity of studies involving school-age children. More research is needed to confirm our findings also due to continuing technological progress

Human GLB1 knockout cerebral organoids: A model system for testing AAV9-mediated GLB1 gene therapy for reducing GM1 ganglioside storage in GM1 gangliosidosis

GM1 gangliosidosis is an autosomal recessive neurodegenerative disorder caused by the deficiency of lysosomal gangliosidebeta-galactosidase (beta-gal) and resulting in accumulation of GM1 ganglioside. The disease spectrum ranges from infantile to late onset and is uniformly fatal, with no effective therapy currently available. Although animal models have been useful for understanding disease pathogenesis and exploring therapeutic targets, no relevant human central nervous system (CNS) model system has been available to study its early pathogenic events or test therapies. To develop a model of human GM1 gangliosidosis in the CNS, we employed CRISPR/Cas9 genome editing to target GLB1 exons 2 and 6, common sites for mutations in patients, to create isogenic induced pluripotent stem (iPS) cell lines with lysosomal beta-gal deficiency. We screened for clones with \u3c 5% of parental cell line beta-gal enzyme activity and confirmed GLB1 knockout clones using DNA sequencing. We then generated GLB1 knockout cerebral organoids from one of these GLB1 knockout iPS cell clones. Analysis of GLB1 knockout organoids in culture revealed progressive accumulation of GM1 ganglioside. GLB1 knockout organoids microinjected with AAV9-GLB1 vector showed a significant increase in beta-gal activity and a significant reduction in GM1 ganglioside content compared with AAV9-GFP-injected organoids, demonstrating the efficacy of an AAV9 gene therapy-based approach in GM1 gangliosidosis. This proof-of-concept in a human cerebral organoid model completes the pre-clinical studies to advance to clinical trials using the AAV9-GLB1 vector

Cell fate takes a slug in BRCA1-associated breast cancer

Understanding why BRCA1 mutation carriers have a predilection for developing clinically aggressive basal-like breast tumors could inform the development of targeted treatment or prevention strategies. Analysis of both mouse and human mammary epithelial cells has identified a role for BRCA1 in orchestrating differentiation. The ability to isolate discrete epithelial subpopulations from mammary tissue has recently directed attention to luminal progenitor cells - the descendants of mammary stem cells - as the likely 'cells-of-origin' in BRCA1-associated breast cancer. A new publication has confirmed the importance of aberrant luminal cells as key culprits and provided insights on how BRCA1 haploinsufficiency biases luminal cells toward a basal-like fate through aberrant expression of the transcription factor SLUG

Sphingosine-1-Phosphate Enhances Satellite Cell Activation in Dystrophic Muscles through a S1PR2/STAT3 Signaling Pathway

Sphingosine-1-phosphate (S1P) activates a widely expressed family of G protein-coupled receptors, serves as a muscle trophic factor and activates muscle stem cells called satellite cells (SCs) through unknown mechanisms. Here we show that muscle injury induces dynamic changes in S1P signaling and metabolism in vivo. These changes include early and profound induction of the gene encoding the S1P biosynthetic enzyme SphK1, followed by induction of the catabolic enzyme sphingosine phosphate lyase (SPL) 3 days later. These changes correlate with a transient increase in circulating S1P levels after muscle injury. We show a specific requirement for SphK1 to support efficient muscle regeneration and SC proliferation and differentiation. Mdx mice, which serve as a model for muscular dystrophy (MD), were found to be S1P-deficient and exhibited muscle SPL upregulation, suggesting that S1P catabolism is enhanced in dystrophic muscle. Pharmacological SPL inhibition increased muscle S1P levels, improved mdx muscle regeneration and enhanced SC proliferation via S1P receptor 2 (S1PR2)-dependent inhibition of Rac1, thereby activating Signal Transducer and Activator of Transcription 3 (STAT3), a central player in inflammatory signaling. STAT3 activation resulted in p21 and p27 downregulation in a S1PR2-dependent fashion in myoblasts. Our findings suggest that S1P promotes SC progression through the cell cycle by repression of cell cycle inhibitors via S1PR2/STAT3-dependent signaling and that SPL inhibition may provide a therapeutic strategy for MD

Mitochondrial Electron Transport Is the Cellular Target of the Oncology Drug Elesclomol

Elesclomol is a first-in-class investigational drug currently undergoing clinical evaluation as a novel cancer therapeutic. The potent antitumor activity of the compound results from the elevation of reactive oxygen species (ROS) and oxidative stress to levels incompatible with cellular survival. However, the molecular target(s) and mechanism by which elesclomol generates ROS and subsequent cell death were previously undefined. The cellular cytotoxicity of elesclomol in the yeast S. cerevisiae appears to occur by a mechanism similar, if not identical, to that in cancer cells. Accordingly, here we used a powerful and validated technology only available in yeast that provides critical insights into the mechanism of action, targets and processes that are disrupted by drug treatment. Using this approach we show that elesclomol does not work through a specific cellular protein target. Instead, it targets a biologically coherent set of processes occurring in the mitochondrion. Specifically, the results indicate that elesclomol, driven by its redox chemistry, interacts with the electron transport chain (ETC) to generate high levels of ROS within the organelle and consequently cell death. Additional experiments in melanoma cells involving drug treatments or cells lacking ETC function confirm that the drug works similarly in human cancer cells. This deeper understanding of elesclomol's mode of action has important implications for the therapeutic application of the drug, including providing a rationale for biomarker-based stratification of patients likely to respond in the clinical setting