Role of Mitochondria in Tributyltin-Induced Interleukin-1α Production in Murine Keratinocytes

Tributyltin (TBT) salts are well known skin irritants in rodents and humans. TBT induced both the intracellular production of Interleukin-1α (IL-1α) and its release into culture medium in a murine keratinocyte cell line (HEL30). Here, we report that mitochondria are important for TBT-induced IL-1α production.Confluent cells were treated with increasing concentrations of TBT (0–2.5 μM) or dimethylsulfoxide as vehicle control. At different times thereafter (0–24 h), nuclear extracts were analyzed for nuclear factor-κB (NF-κB) binding activity by electrophoretic mobility shift assay, and the released and cell-associated IL-1α was measured by enzyme-linked immunosorbent assay. TBT induced a direct and concentration-related activation of NF-κB, which peaked at 2h and was blocked by pyrrolidinedithiocarbamate, a potent NF-κB inhibitor, and rotenone, an inhibitor of the electron entry from complex I to ubiquinone. Rotenone also induced a concentration-related inhibition of IL-1α synthesis induced by TBT, but rotenone did not completely abrogate TBT-induced IL-1α production, which suggests that other transcription factors may be involved in IL-1α production.Prolongod treatment with ethidium bromide, an inhibitor of mitochondrial DNA and RNA synthesis, was used to partially deplete cells of functional mitochondria. After 5 d of treatment, mitochondria conversion of tetrazolium bromide to formazan was reduced by 50%, and IL-1α release was decreased by 65%, whereas no induction of intracellular IL-1α was observed. This effect was not due to inhibition prot in synthesis because identical incorporation of [3H]leucine into protein in control and ethidium bromide–treated cells was identical. This impairment of mitochondrial metabolism inhibited NF-κB activation by TBT. These findings indicate that mitochondria may be the source of second messenger molecules important for TBT-induced IL-1α production

Role of SP-1 in SDS-Induced Adipose Differentiation Related Protein Synthesis in Human Keratinocytes

Skin irritation is a complex phenomenon, and keratinocytes play an important role in it. We have recently characterized the expression and protective role of adipose differentiation related protein (ADRP) in skin irritation. In particular, ADRP expression is induced to recover functional cell membrane following the cell damage caused by skin irritants

Endogenous erythropoietin as part of the cytokine network in the pathogenesis of experimental autoimmune encephalomyelitis

Erythropoietin (EPO) is of great interest as a therapy for many of the central nervous system (CNS) diseases and its administration is protective in experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS). Endogenous EPO is induced by hypoxic/ischemic injury, but little is known about its expression in other CNS diseases. We report here that EPO expression in the spinal cord is induced in mouse models of chronic or relapsing-remitting EAE, and is prominently localized to motoneurons. We found a parallel increase of hypoxia-inducible transcription factor (HIF)-1 alpha, but not HIF-2 alpha, at the mRNA level, suggesting a possible role of non-hypoxic factors in EPO induction. EPO mRNA in the spinal cord was co-expressed with interferon (IFN)-gamma and tumor necrosis factor (TNF), and these cytokines inhibited EPO production in vitro in both neuronal and glial cells. Given the known inhibitory effect of EPO on neuroinflammation, our study indicates that EPO should be viewed as part of the inflammatory/anti-inflammatory network in MS

Toxicological profile of PM from different sources in the bronchial epithelial cell line BEAS-2B

The toxicity of particulate matter (PM) is strictly associated with its physical-chemical characteristics, such as size or chemical composition. While these properties depend on the origin of the particles, the study of the toxicological profile of PM from single sources has rarely been highlighted. Hence, the focus of this research was to investigate the biological effects of PM from five relevant sources of atmospheric PM: diesel exhaust particles, coke dust, pellet ashes, incinerator ashes, and brake dust. Cytotoxicity, genotoxicity, oxidative, and inflammatory response were assessed in a bronchial cell line (BEAS-2B). BEAS-2B cells were exposed to different concentrations (25, 50, 100, and 150 g/mL medium) of particles suspended in water. The exposure lasted 24 h for all the assays performed, except for reactive oxygen species, which were evaluated after 30 min, 1 h, and 4 h of treatment. The results showed a different action of the five types of PM. All the tested samples showed a genotoxic action on BEAS-2B, even in the absence of oxidative stress induction. Pellet ashes seemed to be the only ones able to induce oxidative stress by boosting the formation of reactive oxygen species, while brake dust resulted in the most cytotoxic. In conclusion, the study elucidated the differential response of bronchial cells to PM samples generated by different sources. The comparison could be a starting point for a regulatory intervention since it highlighted the toxic potential of each type of PM tested

Distribution of interleukin-1 receptor complex at the synaptic membrane driven by interleukin-1β and NMDA stimulation

Interleukin-1β (IL-1β) is a pro-inflammatory cytokine that contributes to neuronal injury in various degenerative diseases, and is therefore a potential therapeutic target. It exerts its biological effect by activating the interleukin-1 receptor type I (IL-1RI) and recruiting a signalling core complex consisting of the myeloid differentiation primary response protein 88 (MyD88) and the IL-1R accessory protein (IL-1RAcP). This pathway has been clearly described in the peripheral immune system, but only scattered information is available concerning the molecular composition and distribution of its members in neuronal cells. The findings of this study show that IL-1RI and its accessory proteins MyD88 and IL-1RAcP are differently distributed in the hippocampus and in the subcellular compartments of primary hippocampal neurons. In particular, only IL-1RI is enriched at synaptic sites, where it co-localises with, and binds to the GluN2B subunit of NMDA receptors. Furthermore, treatment with NMDA increases IL-1RI interaction with NMDA receptors, as well as the surface expression and localization of IL-1RI at synaptic membranes. IL-1β also increases IL-1RI levels at synaptic sites, without affecting the total amount of the receptor in the plasma membrane. Our results reveal for the first time the existence of a dynamic and functional interaction between NMDA receptor and IL-1RI systems that could provide a molecular basis for IL-1β as a neuromodulator in physiological and pathological events relying on NMDA receptor activation

Erythropoietin Selectively Attenuates Cytokine Production and Inflammation in Cerebral Ischemia by Targeting Neuronal Apoptosis

Ischemic brain injury resulting from stroke arises from primary neuronal losses and by inflammatory responses. Previous studies suggest that erythropoietin (EPO) attenuates both processes. Although EPO is clearly antiapoptotic for neurons after experimental stroke, it is unknown whether EPO also directly modulates EPO receptor (EPO-R)–expressing glia, microglia, and other inflammatory cells. In these experiments, we show that recombinant human EPO (rhEPO; 5,000 U/kg body weight, i.p.) markedly reduces astrocyte activation and the recruitment of leukocytes and microglia into an infarction produced by middle cerebral artery occlusion in rats. In addition, ischemia-induced production of the proinflammatory cytokines tumor necrosis factor, interleukin 6, and monocyte chemoattractant protein 1 concentration is reduced by >50% after rhEPO administration. Similar results were also observed in mixed neuronal-glial cocultures exposed to the neuronal-selective toxin trimethyl tin. In contrast, rhEPO did not inhibit cytokine production by astrocyte cultures exposed to neuronal homogenates or modulate the response of human peripheral blood mononuclear cells, rat glial cells, or the brain to lipopolysaccharide. These findings suggest that rhEPO attenuates ischemia-induced inflammation by reducing neuronal death rather than by direct effects upon EPO-R–expressing inflammatory cells

The epidemiology of renal replacement therapy in two different parts of the worldThe Latin American Dialysis and Transplant Registry versus the European Renal Association-European Dialysis and Transplant Association Registry

Publisher Copyright: © 2018 Pan American Health Organization. All rights reserved.Objective: To compare the epidemiology of renal replacement therapy (RRT) for end-stage renal disease (ESRD) in Latin America and Europe, as well as to study differences in macro-economic indicators, demographic and clinical patient characteristics, mortality rates, and causes of death between these two populations. Methods: We used data from 20 Latin American and 49 European national and subnational renal registries that had provided data to the Latin American Dialysis and Renal Transplant Registry (RLADTR) and the European Renal Association-European Dialysis and Transplant Association (ERA-EDTA) Registry, respectively. The incidence and prevalence of RRT in 2013 were calculated per million population (pmp), overall and by subcategories of age, sex, primary renal disease, and treatment modality. The correlation between gross domestic product and the prevalence of RRT was analyzed using linear regression. Trends in the prevalence of RRT between 2004 and 2013 were assessed using Joinpoint regression analysis. Results: In 2013, the overall incidence at day 91 after the onset of RRT was 181 pmp for Latin American countries and 130 pmp for European countries. The overall prevalence was 660 pmp for Latin America and 782 pmp for Europe. In the Latin American countries, the annual increase in the prevalence averaged 4.0% (95% confdence interval (CI): 2.5%-5.6%) from 2004 to 2013, while the European countries showed an average annual increase of 2.2% (95% CI: 2.0%-2.4%) for the same time period. The crude mortality rate was higher in Latin America than in Europe (112 versus 100 deaths per 1 000 patient-years), and cardiovascular disease was the main cause of death in both of those regions. Conclusions. There are considerable differences between Latin America and Europe in the epidemiology of RRT for ESRD. Further research is needed to explore the reasons for these differences.Peer reviewe

Risk Characterization of Botanical Extracts Containing Hydroxyanthracenes as Determined by a Validated Micronucleus In Vitro Assay

Extracts of Rheum palmatum L., Rhamnus purshiana DC., Rhamnus frangula L., and Cassia senna L. are used in traditional medicine thanks to their beneficial properties. These species contain hydroxyanthracene derivatives, considered genotoxic and possibly related to colorectal cancer development. This research aimed to study, using a micronucleus assay in vitro, the genotoxic potential of Rheum palmatum L., Rhamnus purshiana DC., Rhamnus frangula L. (bark), and Cassia senna L. (leaves and fruits) extracts. The extracts were evaluated at different concentrations: from 0 to 2000 µg/mL for Rhamnus purshiana DC, from 0 to 2500 µg/mL for Rheum palmatum L. and Rhamnus frangula L., and from 0 to 5000 µg/mL for Cassia senna L. The cytokinesis-block proliferation index was calculated to analyse if the used concentrations showed cytotoxicity. The hydroxyanthracene content varied between 0.06% and 0.23% for aloe-emodin, and between 0.07% and 0.16% for emodin and rhein. No cytotoxic effect was detected at any of these concentrations. Micronucleus analyses showed a lack of genotoxicity for all the extracts tested. These results show that Rheum palmatum L., Rhamnus purshiana DC, Rhamnus frangula L., and Cassia senna L. extracts do not induce genotoxicity since no increase in micronuclei formation in human lymphocytes in vitro was detected

Skin pharmacology and toxicology: recent advances

viii+318hlm.;26c