Necroptosis is a programmed form of necrotic cell death, which is tightly regulated by the necroptotic signaling pathway containing receptor-interacting protein (RIP)1, RIP3, and mixed-lineage kinase domain-like (MLKL) protein. In addition to the RIP1-RIP3-MLKL axis, other factors regulating necroptosis are still largely unknown. Here a cell-based small-molecule screening led to the finding that BET inhibitors protected cells from necroptosis in the TNFα/Smac-mimetic/Z-VAD-FMK (TSZ)-induced cell necroptosis model. Mechanistic studies revealed that BET inhibitors acted by downregulating MLKL expression. Further research demonstrated that BRD4, IRF1, P-TEFb, and RNA polymerase II formed a transcription complex to regulate the expression of MLKL, and BET inhibitors interfered with the transcription complex formation. In necroptosis-related disease model, the BET inhibitor JQ-1 showed promising therapeutic effects. Collectively, our studies establish, for the first time, BRD4 as a new epigenetic factor regulating necroptosis, and highlight the potential of BET inhibitors in the treatment of necroptosis-related diseases.
Alpha6beta2 nicotinic acetylcholine receptors (nAChRs) are potential therapeutic targets for the treatment of several neuropsychiatric diseases, including addiction and Parkinson’s disease. Alpha-conotoxin (α-CTx) TxIB is a uniquely selective ligand, which blocks α6/α3β2β3 nAChRs only, but does not block the other subtypes. Therefore, α-CTx TxIB is a valuable therapeutic candidate peptide. Synthesizing enough α-CTx TxIB with high yield production is required for conducting wide-range testing of its potential medicinal applications. The current study optimized the cleavage of synthesized α-CTx TxIB resin-bounded peptide and folding of the cleaved linear peptide. Key parameters influencing cleavage and oxidative folding of α-CTx TxIB were examined, such as buffer, redox agents, pH, salt, co-solvent and temperature. Twelve conditions were used for cleavage optimization. Fifty-four kinds of one-step oxidative solution were used to assess their effects on each α-CTx TxIB isomers’ yield. The result indicated that co-solvent choices were particularly important. Completely oxidative folding of globular isomer was achieved when the NH4HCO3 or Tris-HCl folding buffer at 4 °C contained 40% of co-solvent DMSO, and GSH:GSSG (2:1) or GSH only with pH 8~8.7.
Background: Silver nanoparticles (AgNPs), as promising anti-microbials and anti-cancer therapeutics, the toxicological effect and killing efficiency towards cells need in-depth investigation for better applications in daily life and healthcare fields. Thus far, limited studies have yet elucidated the protein targets of AgNPs and silver ions (Ag +) released from intracellular AgNPs dissolution in hepatocytes, as well as potential interaction mechanism. Results: Through integrating proteomic and metallomic methodologies, six intracellular protein targets (i.e. glutathione S-transferase (GST), peroxiredoxin, myosin, elongation factor 1, 60S ribosomal protein and 40S ribosomal protein) were ultimately identified and confirmed as AgNPs-and Ag + −binding proteins. Toward a deep understanding the direct interaction mechanism between AgNPs and these protein targets, GST was chosen as a representative for toxicological investigation. The results revealed that AgNPs could remarkably deplete the enzyme activity of GST but did not depress the expressions, resulting in elevated intracellular oxidative stress and cell death. Finally, both "Ag + effect" and "particle-specific effect" were demonstrated to concomitantly account for the overall cytotoxicity of AgNPs, and the former relatively contributed more via activity depletion of GST. Conclusions: Collectively, our major contribution is the development of an efficient strategy to identify the intracellular AgNPs-targeted protein (e.g. GST) through integrating proteomic and metallomic methodologies, which is helpful to accelerate the interpretation of underlying toxicological mechanism of AgNPs.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.