Cytosolic sensing of pathogens and damage by myeloid and barrier epithelial cells assembles large complexes called inflammasomes, which activate inflammatory caspases to process cytokines (IL-1β) and gasdermin D (GSDMD). Cleaved GSDMD forms membrane pores, leading to cytokine release and inflammatory cell death (pyroptosis). Inhibiting GSDMD is an attractive strategy to curb inflammation. Here we identify disulfiram, a drug for treating alcohol addiction, as an inhibitor of pore formation by GSDMD, but not other members of the GSDM family. Disulfiram blocks pyroptosis and cytokine release in cells and lipopolysaccharide (LPS)-induced septic death in mice. At nanomolar concentration, disulfiram covalently modifies human/mouse Cys191/Cys192 in GSDMD to block pore formation. Disulfiram still allows IL-1β and GSDMD processing, but abrogates pore formation, thereby preventing IL-1β release and pyroptosis. The role of disulfiram in inhibiting GSDMD provides new therapeutic indications for repurposing this safe drug to counteract inflammation, which contributes to many human diseases.

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Inflammasomes are supramolecular complexes that play key roles in immune surveillance. This is accomplished by the activation of inflammatory caspases, which leads to the proteolytic maturation of interleukin 1β (IL-1β) and pyroptosis. Here, we show that nucleotide-binding domain, leucine-rich repeat, and pyrin domain–containing protein 3 (NLRP3)- and pyrin-mediated inflammasome assembly, caspase activation, and IL-1β conversion occur at the microtubule-organizing center (MTOC). Furthermore, the dynein adapter histone deacetylase 6 (HDAC6) is indispensable for the microtubule transport and assembly of these inflammasomes both in vitro and in mice. Because HDAC6 can transport ubiquitinated pathological aggregates to the MTOC for aggresome formation and autophagosomal degradation, its role in NLRP3 and pyrin inflammasome activation also provides an inherent mechanism for the down-regulation of these inflammasomes by autophagy. This work suggests an unexpected parallel between the formation of physiological and pathological aggregates.

The atomic force microscope is used to measure dielectric polarization forces on surfaces induced by a charged tip. On insulators, the major contribution to the surface polarizability at low frequencies is from surface ions. The mobility of these ions depends strongly on the humidity. Using polarization forces we have been able to image liquid films, droplets, and other weakly adsorbed material.

Peroxynitrite (ONOO(-)), the product of a radical combination reaction of nitric oxide and superoxide, is a potent biological oxidant involved in a broad spectrum of physiological and pathological processes. Herein we report the development, characterization, and biological applications of a new fluorescent probe, HKGreen-4, for peroxynitrite detection and imaging. HKGreen-4 utilizes a peroxynitrite-triggered oxidative N-dearylation reaction to achieve an exceptionally sensitive and selective fluorescence turn-on response toward peroxynitrite in chemical systems and biological samples. We have thoroughly evaluated the utility of HKGreen-4 for intracellular peroxynitrite imaging and, more importantly, demonstrated that HKGreen-4 can be efficiently employed to visualize endogenous peroxynitrite generated in Escherichia coli-challenged macrophages and in live tissues from a mouse model of atherosclerosis. This probe should serve as a powerful molecular imaging tool to explore peroxynitrite biology under a variety of physiological and pathological contexts.

To obtain one biodegradable and electroactive polymer as the scaffold for tissue engineering, the multiblock copolymer PLAAP was designed and synthesized with the condensation polymerization of hydroxyl-capped poly( l-lactide) (PLA) and carboxyl-capped aniline pentamer (AP). The PLAAP copolymer exhibited excellent electroactivity, solubility, and biodegradability. At the same time, as one scaffold material, PLAAP copolymer possesses certain mechanical properties with the tensile strength of 3 MPa, tensile Young 's modulus of 32 MPa, and breaking elongation rate of 95%. We systematically studied the compatibility of PLAAP copolymer in vitro and proved that the electroactive PLAAP copolymer was innocuous, biocompatible, and helpful for the adhesion and proliferation of rat C6 cells. Moreover, the PLAAP copolymer stimulated by electrical signals was demonstrated as accelerating the differentiation of rat neuronal pheochromocytoma PC-12 cells. This biodegradable and electroactive PLAAP copolymer thus possessed the properties in favor of the long-time application in vivo as nerve repair scaffold materials in tissue engineering.

Superoxide anion radical (O2(•-)) is undoubtedly the most important primary reactive oxygen species (ROS) found in cells, whose formation and fate are intertwined with diverse physiological and pathological processes. Here we report a highly sensitive and selective O2(•-) detecting strategy involving O2(•-) cleavage of an aryl trifluoromethanesulfonate group to yield a free phenol. We have synthesized three new O2(•-) fluorescent probes (HKSOX-1, HKSOX-1r for cellular retention, and HKSOX-1m for mitochondria-targeting) which exhibit excellent selectivity and sensitivity toward O2(•-) over a broad range of pH, strong oxidants, and abundant reductants found in cells. In confocal imaging, flow cytometry, and 96-well microplate assay, HKSOX-1r has been robustly applied to detect O2(•-) in multiple cellular models, such as inflammation and mitochondrial stress. Additionally, our probes can be efficiently applied to visualize O2(•-) in intact live zebrafish embryos. These probes open up exciting opportunities for unmasking the roles of O2(•-) in health and disease.

Investigation into the interactions between graphene oxide (GO) and biomolecules is very important for broad applications of GO in bioassay and bioanalysis. In this work, we describe the interactions between double-stranded DNA (dsDNA) and GO. We demonstrated that dsDNA can bind to GO forming complexes (dsDNA/GO) in the presence of certain salts, which protects dsDNA from being enzymatically digested. On the other hand, we found that a nonionic surfactant, such as triton X-100, can block the formation of dsDNA/GO complexes, so that the enzymatic digestion of dsDNA is restored. These results lead us to believe that the reason for GO protecting dsDNA from enzymatic digestion is the formation of dsDNA/GO complexes hindering the access of DNA enzymes to dsDNA, rather than direct inactivation of the DNA enzymes.