5-5--6-6--tetrachloro-1-1--3-3--tetraethylbenzimidazolocarbocyanine and benzyloxycarbonylleucyl-leucyl-leucine-aldehyde

Iron plays a pivotal role in the pathogenesis of Trichomonas vaginalis, the causative agent of highly prevalent human trichomoniasis. T. vaginalis resides in the vaginal region, where the iron concentration is constantly changing. Hence, T. vaginalis must adapt to variations in iron availability to establish and maintain an infection. The free radical signaling molecules reactive oxygen species (ROS) and reactive nitrogen species (RNS) have been proven to participate in iron deficiency in eukaryotes. However, little is known about the roles of these molecules in iron-deficient T. vaginalis.. T. vaginalis cultured in iron-rich and -deficient conditions were collected for all experiments in this study. Next generation RNA sequencing was conducted to investigate the impact of iron on transcriptome of T. vaginalis. The cell viabilities were monitored after the trophozoites treated with the inhibitors of nitric oxide (NO) synthase (L-NG-monomethyl arginine, L-NMMA) and proteasome (MG132). Hydrogenosomal membrane potential was measured using JC-1 staining.. We demonstrated that NO rather than ROS accumulates in iron-deficient T. vaginalis. The level of NO was blocked by MG132 and L-NMMA, indicating that NO production is through a proteasome and arginine dependent pathway. We found that the inhibition of proteasome activity shortened the survival of iron-deficient cells compared with untreated iron-deficient cells. Surprisingly, the addition of arginine restored both NO level and the survival of proteasome-inhibited cells, suggesting that proteasome-derived NO is crucial for cell survival under iron-limited conditions. Additionally, NO maintains the hydrogenosomal membrane potential, a determinant for cell survival, emphasizing the cytoprotective effect of NO on iron-deficient T. vaginalis. Collectively, we determined that NO produced by the proteasome prolonged the survival of iron-deficient T. vaginalis via maintenance of the hydrogenosomal functions.. The findings in this study provide a novel role of NO in adaptation to iron-deficient stress in T. vaginalis and shed light on a potential therapeutic strategy for trichomoniasis.

Topics: Adaptation, Physiological; Animals; Base Sequence; Benzimidazoles; Carbocyanines; Cell Survival; Enzyme Inhibitors; High-Throughput Nucleotide Sequencing; Humans; Iron Deficiencies; Leupeptins; Models, Biological; Nitric Oxide; Nitric Oxide Synthase; omega-N-Methylarginine; Protozoan Proteins; Reactive Oxygen Species; Sequence Analysis, RNA; Transcriptome; Trichomonas Infections; Trichomonas vaginalis

Decreased proteasome activity is an important pathology in Parkinson's disease (PD), which is related to cell death and Lewy body formation. In this study, we show that p53-activity may correlate with neuronal death via the mitochondrial pathway in PD model. The proteasome inhibitor, MG132, induced the accumulation of p53 in human dopaminergic neuroblastoma SH-SY5Y cells. The increased stabilization of p53 upregulated the level of Bax and mitochondrial depolarization. These events were inhibited by the p53 inhibitor, pifithrin-alpha (PFT). Cell viability analyzes demonstrated that PFT partially prevented MG132-induced cell death. These results suggest that p53 is a candidate as an intermediary between the proteasome system and mitochondria-related neuronal death in PD.

Topics: bcl-2-Associated X Protein; Benzimidazoles; Benzothiazoles; Blotting, Western; Carbocyanines; Cell Death; Cell Line, Tumor; Cell Survival; Cysteine Endopeptidases; Cysteine Proteinase Inhibitors; Dopamine; Dose-Response Relationship, Drug; Drug Interactions; Fluorescent Antibody Technique; Humans; Leupeptins; Membrane Potentials; Mitochondria; Multienzyme Complexes; Neuroblastoma; Proteasome Endopeptidase Complex; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-bcl-2; Thiazoles; Time Factors; Toluene; Tumor Suppressor Protein p53