160 research outputs found
Targeting Transcriptional Dysregulation in Huntingtonâs Disease: Description of Therapeutic Approaches
The effect of the discounted attribute importance in two-sided messages
Purpose â The purpose of this research is to test the importance of the discounting attribute in the two-sided communication from a retail salesperson as a boundary condition that eliminates the trade-off between trustworthiness and purchase intentions. Design/methodology/approach â The hypotheses are tested by three experimental studies in three different retail contexts. Two lab studies manipulate the importance of the attribute and the type of message: one-sided vs two-sided. A field study improves the external validity of the findings. Findings â A two-sided message from a salesperson reduces the use of persuasion knowledge and, therefore, enhances the consumerâs perception of the salespersonâs trustworthiness; this positive effect remains significant across different levels of importance of the discounting attribute. A two-sided message decreases the consumerâs probability of purchase only when an important attribute is disclaimed, through the consumerâs beliefs regarding the productâs attributes. Practical implications â For the appropriate use of two-sided appeals, retailers should identify the importance of product attributes from the consumersâ perspective. A negative remark from a salesperson when referred to an unimportant attribute makes no harm to purchase intentions while leading to stronger intentions to return to the store and to recommend the store by enhancing trustworthiness. Originality/value â This paper shows that it is possible to enhance trustworthiness through a two-sided message without mitigating the intentions of buying by discounting an attribute at low importance in the two-sided message
Histone Deacetylase Inhibitors and Mithramycin A Impact a Similar Neuroprotective Pathway at a Crossroad between Cancer and Neurodegeneration
Mithramycin A (MTM) and histone deacetylase inhibitors (HDACi) are effective therapeutic agents for cancer and neurodegenerative diseases. MTM is a FDA approved aureolic acid-type antibiotic that binds to GC-rich DNA sequences and interferes with Sp1 transcription factor binding to its target sites (GC box). HDACi, on the other hand, modulate the activity of class I and II histone deacetylases. They mediate their protective function, in part, by regulating the acetylation status of histones or transcription factors, including Sp1, and in turn chromatin accessibility to the transcriptional machinery. Because these two classes of structurally and functionally diverse compounds mediate similar therapeutic functions, we investigated whether they act on redundant or synergistic pathways to protect neurons from oxidative death. Non-protective doses of each of the drugs do not synergize to create resistance to oxidative death suggesting that these distinct agents act via a similar pathway. Accordingly, we found that protection by MTM and HDACi is associated with diminished expression of the oncogene, Myc and enhanced expression of a tumor suppressor, p21waf1/cip1. We also find that neuroprotection by MTM or Myc knockdown is associated with downregulation of class I HDAC levels. Our results support a model in which the established antitumor drug MTM or canonical HDACi act via distinct mechanisms to converge on the downregulation of HDAC levels or activity respectively. These findings support the conclusion that an imbalance in histone acetylase and HDAC activity in favor of HDACs is key not only for oncogenic transformation, but also neurodegeneration
Role of Extracellular Vesicles in Amyotrophic Lateral Sclerosis
Amyotrophic Lateral Sclerosis (ALS) is the most common motor neuron disease in adults and primarily targets upper and lower motor neurons. The progression of the disease is mostly mediated by altered intercellular communication in the spinal cord between neurons and glial cells. One of the possible ways by which intercellular communication occurs is through extracellular vesicles (EVs) that are responsible for the horizontal transfer of proteins and RNAs to recipient cells. EVs are nanoparticles released by the plasma membrane and this review will describe all evidence connecting ALS, intercellular miscommunication and EVs. We mainly focus on mutant proteins causing ALS and their accumulation in EVs, along with the propensity of mutant proteins to misfold and propagate through EVs in prion-like behavior. EVs are a promising source of biomarkers and the state of the art in ALS will be discussed along with the gaps and challenges still present in this blooming field of investigation
Hydroxamic Acid-Based Histone Deacetylase (HDAC) Inhibitors Can Mediate Neuroprotection Independent of HDAC Inhibition
Histone deacetylase (HDAC) inhibition improves function and extends survival in rodent models of a host of neurological conditions, including stroke, and neurodegenerative diseases. Our understanding, however, of the contribution of individual HDAC isoforms to neuronal death is limited. In this study, we used selective chemical probes to assess the individual roles of the Class I HDAC isoforms in protecting Mus musculus primary cortical neurons from oxidative death. We demonstrated that the selective HDAC8 inhibitor PCI-34051 is a potent neuroprotective agent; and by taking advantage of both pharmacological and genetic tools, we established that HDAC8 is not critically involved in PCI-34051\u27s mechanism of action. We used BRD3811, an inactive ortholog of PCI-34051, and showed that, despite its inability to inhibit HDAC8, it exhibits robust neuroprotective properties. Furthermore, molecular deletion of HDAC8 proved insufficient to protect neurons from oxidative death, whereas both PCI-34051 and BRD3811 were able to protect neurons derived from HDAC8 knock-out mice. Finally, we designed and synthesized two new, orthogonal negative control compounds, BRD9715 and BRD8461, which lack the hydroxamic acid motif and showed that they stably penetrate cell membranes but are not neuroprotective. These results indicate that the protective effects of these hydroxamic acid-containing small molecules are likely unrelated to direct epigenetic regulation via HDAC inhibition, but rather due to their ability to bind metals. Our results suggest that hydroxamic acid-based HDAC inhibitors may mediate neuroprotection via HDAC-independent mechanisms and affirm the need for careful structure-activity relationship studies when using pharmacological approaches
A comparison between 18F-FDG PET/CT imaging and biological and radiological findings in restaging of hepatoblastoma patients
Background. In this study we retrospectively evaluated if 18F-FDG-PET/CT provided incremental diagnostic information over CI in a group of hepatoblastoma patients performing restaging. Procedure. Nine patients (mean age: 5.9âyears; range: 3.1â12âyears) surgically treated for hepatoblastoma were followed up by clinical examination, serum α-FP monitoring, and US. CI (CT or MRI) and PET/CT were performed in case of suspicion of relapse. Fine-needle aspiration biopsies (FNAB) were carried out for final confirmation if the results of CI, PET/CT, and/or α-FP levels were suggestive of relapse. PET/CT and CI findings were analyzed for comparison purposes, using FNAB as reference standard. Results. α-FP level was suggestive of disease recurrence in 8/9 patients. Biopsy was performed in 8/9âcases. CI and PET/CT resulted to be concordant in 5/9 patients (CI identified recurrence of disease, but 18F-FDG-PET/CT provided a better definition of disease extent); in 4/9 cases, CI diagnostic information resulted in negative findings, whereas PET/CT correctly detected recurrence of disease. 18F-FDG-PET/CT showed an agreement of 100% (8/8) with FNAB results. Conclusions. 18F-FDG-PET/CT scan seems to better assess HB patients with respect to CI and may provide incremental diagnostic value in the restaging of this group of patients
Risk Factors and Outcomes Related to Pediatric Intensive Care Unit Admission after Hematopoietic Stem Cell Transplantation: A Single-Center Experience
Abstract To describe incidence, causes, and outcomes related to pediatric intensive care unit (PICU) admission for patients undergoing hematopoietic stem cell transplantation (HSCT), we investigated the risk factors predisposing to PICU admission and prognostic factors in terms of patient survival. From October 1998 to April 2015, 496 children and young adults (0 to 23 years) underwent transplantation in the HSCT unit. Among them, 70 (14.1%) were admitted to PICU. The 3-year cumulative incidence of PICU admission was 14.3%. The main causes of PICU admission were respiratory failure (36%), multiple organ failure (16%), and septic shock (13%). The overall 90-day cumulative probability of survival after PICU admission was 34.3% (95% confidence interval, 24.8% to 47.4%). In multivariate analysis, risk factors predisposing to PICU admission were allogeneic HSCT (versus autologous HSCT, P â=â.030) and second or third HSCT ( P â=â.018). Characteristics significantly associated with mortality were mismatched HSCT ( P â=â.011), relapse of underlying disease before PICU admission ( P P â=â.012), hepatic failure at admission ( P â=â.021), and need for invasive ventilation during PICU course (
Altered sphingolipid metabolism in N-(4-hydroxyphenyl) retinamide resistant A2780 human ovarian carcinoma cells
In the present work, we studied the effects of fenretinide (N-(4-hydroxyphenyl)retinamide (HPR)), a hydroxyphenyl derivative of all-trans-retinoic acid, on sphingolipid metabolism and expression in human ovarian carcinoma A2780 cells. A2780 cells, which are sensitive to a pharmacologically achievable HPR concentration, become 10-fold more resistant after exposure to increasing HPR concentrations. Our results showed that HPR was able to induce a dose- and time-dependent increase in cellular ceramide levels in sensitive but not in resistant cells. This form of resistance in A2780 cells was not accompanied by the overexpression of multidrug resistance-specific proteins MDR1 P-glycoprotein and multidrug resistance-associated protein, whose mRNA levels did not differ in sensitive and resistant A2780 cells. HPR-resistant cells were characterized by an overall altered sphingolipid metabolism. The overall content in glycosphingolipids was similar in both cell types, but the expression of specific glycosphingolipids was different. Specifically, our findings indicated that glucosylceramide levels were similar in sensitive and resistant cells, but resistant cells were characterized by a 6-fold lower expression of lactosylceramide levels and by a 6-fold higher expression of ganglioside levels than sensitive cells. The main gangliosides from resistant A2780 cells were identified as GM3 and GM2. The possible metabolic mechanisms leading to this difference were investigated. Interestingly, the mRNA levels of glucosylceramide and lactosylceramide synthases were similar in sensitive and resistant cells, whereas GM3 synthase mRNA level and GM3 synthase activity were remarkably higher in resistant cells
Hypoxia-inducible factor prolyl hydroxylases as targets for neuroprotection by âantioxidantâ metal chelators: From ferroptosis to stroke
AbstractNeurologic conditions including stroke, Alzheimer disease, Parkinson disease, and Huntington disease are leading causes of death and long-term disability in the United States, and efforts to develop novel therapeutics for these conditions have historically had poor success in translating from bench to bedside. Hypoxia-inducible factor (HIF)-1α mediates a broad, evolutionarily conserved, endogenous adaptive program to hypoxia, and manipulation of components of the HIF pathway is neuroprotective in a number of human neurological diseases and experimental models. In this review, we discuss molecular components of one aspect of hypoxic adaptation in detail and provide perspective on which targets within this pathway seem to be ripest for preventing and repairing neurodegeneration. Further, we highlight the role of HIF prolyl hydroxylases as emerging targets for the salutary effects of metal chelators on ferroptosis in vitro as well in animal models of neurological diseases
Development of a pluripotent stem cell derived neuronal model to identify chemically induced pathway perturbations in relation to neurotoxicity: Effects of CREB pathway inhibition
JRC.I.5-Systems Toxicolog
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