Sulfur dioxide (SO2) had been recognized as an environmental pollutant produced from industrial processes. SO2 is water soluble and forms hydrated SO2 (SO2·H2O), bisulfite ion (HSO3−), and sulfite ...ion (SO32−) upon dissolution in water. SO2 could be also produced endogenously from sulfur-containing amino acids l-cysteine in mammals. Endogenous SO2 can maintain the balance of biological sulfur and redox equilibrium in vivo, regulate blood insulin levels and reduce blood pressure. Excess intake of exogenous SO2 can result in respiratory diseases, cardiovascular diseases and neurological disorders. As a result, fluorescent probes to detect HSO3−/SO32− have attracted great attention in recent years. Herein, a general overview was provided with the aim to highlight the typical examples of the HSO3−/SO32− fluorescent probes reported since 2010, especially those in the past five years. We have classified HSO3−/SO32− fluorescent probes through different chemical reaction mechanisms and wish this review will give some help to the researchers in this field.
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•84 different reaction-based fluorescent probes for HSO3−/SO32− have been summarized.•These fluorescent probes have been divided into helpful categories according to the chemical mechanism of detection.•The two tables and one figure in the end summarize the entire contents.•This review also provides interesting insights for future developments of fluorescent probes for HSO3−/SO32−.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The synthesis, reactions and medicinal applications of the 1,3,4-thiadiazole ring in solution and the solid phase were investigated. The physical and chemical properties of biosostere and the ...reactions of aromatic and heterocyclic hydrazides with triethyl orthoformate were also explored.
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IJS, KILJ, NUK, PNG, UL, UM
The accumulation of lipid peroxides is recognized as a determinant of the occurrence of ferroptosis. However, the sensors and amplifying process of lipid peroxidation linked to ferroptosis remain ...obscure. Here we identify PKCβII as a critical contributor of ferroptosis through independent genome-wide CRISPR-Cas9 and kinase inhibitor library screening. Our results show that PKCβII senses the initial lipid peroxides and amplifies lipid peroxidation linked to ferroptosis through phosphorylation and activation of ACSL4. Lipidomics analysis shows that activated ACSL4 catalyses polyunsaturated fatty acid-containing lipid biosynthesis and promotes the accumulation of lipid peroxidation products, leading to ferroptosis. Attenuation of the PKCβII-ACSL4 pathway effectively blocks ferroptosis in vitro and impairs ferroptosis-associated cancer immunotherapy in vivo. Our results identify PKCβII as a sensor of lipid peroxidation, and the lipid peroxidation-PKCβII-ACSL4 positive-feedback axis may provide potential targets for ferroptosis-associated disease treatment.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The development of metal‐N‐C materials as efficient non‐precious metal (NPM) catalysts for catalysing the oxygen reduction reaction (ORR) as alternatives to platinum is important for the practical ...use of proton exchange membrane fuel cells (PEMFCs). However, metal‐N‐C materials have high structural heterogeneity. As a result of their high‐temperature synthesis they often consist of metal‐Nx sites and graphene‐encapsulated metal nanoparticles. Thus it is hard to identify the active structure of metal‐N‐C catalysts. Herein, we report a low‐temperature NH4Cl‐treatment to etch out graphene‐encapsulated nanoparticles from metal‐N‐C catalysts without destruction of co‐existing atomically dispersed metal‐Nx sites. Catalytic activity is much enhanced by this selective removal of metallic nanoparticles. Accordingly, we can confirm the spectator role of graphene‐encapsulated nanoparticles and the pivotal role of metal‐Nx sites in the metal‐N‐C materials for ORR in the acidic medium.
ORR inspiring: With a low‐temperature NH4Cl treatment graphene‐encapsulated nanoparticles (NPs) are etched out of metal‐N‐C catalysts. Removing these metallic NPs greatly enhances the catalytic oxygen reduction reaction (ORR) activity allowing the real catalytic centres to be identified.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Hydrogen peroxide (H2O2), as one kind of the most significant reactive oxygen species (ROS), is associated with many physiological and pathological processes in biological systems. Therefore, in ...order to understand the vital roles of H2O2 in living systems, many small-molecule fluorescent probes for its detection in biological field have been reported in recent years. To highlight the recent advances in fluorescence imaging of H2O2, in this review, small-molecule fluorescent probes that detect H2O2 over the recent years (2003–2018) were summarized and organized based on their different response mechanisms. We divided the probes into nine categories. The design strategies of different combinations between fluorophores, recognition groups, and detection mechanisms were all discussed. Finally, we briefly scoped the challenges and future directions in this field. We believe that the essential role of H2O2 in living systems will be understood along with more novel probes or mechanisms coming to light.
Hydrogen peroxide (H2O2) is associated with many physiological and pathological processes in biological systems. Small-molecule fluorescent probes for H2O2 are an important class of fluorescent probes. This article reviewed H2O2 fluorescent probes in the past fifteen years according to different reaction mechanisms. The design strategies, possible response mechanisms, challenges and future directions in this field were discussed here. Display omitted
•Hydrogen peroxide (H2O2) is one kind of the most significant reactive oxygen species (ROS).•Small-molecule fluorescent probes for H2O2 in 2003-2018 were organized based on response mechanisms.•H2O2 probes (including small organic molecules, metal complexes) were discussed.•The design strategies and reaction mechanisms of these probes were described.•The challenges and future directions in this field were discussed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Atomically ordered intermetallic nanoparticles are promising for catalytic applications but are difficult to produce because the high-temperature annealing required for atom ordering inevitably ...accelerates metal sintering that leads to larger crystallites. We prepared platinum intermetallics with an average particle size of <5 nanometers on porous sulfur-doped carbon supports, on which the strong interaction between platinum and sulfur suppresses metal sintering up to 1000°C. We synthesized intermetallic libraries of small nanoparticles consisting of 46 combinations of platinum with 16 other metal elements and used them to study the dependence of electrocatalytic oxygen-reduction reaction activity on alloy composition and platinum skin strain. The intermetallic libraries are highly mass efficient in proton-exchange-membrane fuel cells and could achieve high activities of 1.3 to 1.8 amperes per milligram of platinum at 0.9 volts.
Ferroptosis is an iron-dependent, non-apoptotic form of programmed cell death driven by excessive lipid peroxidation (LPO). Mounting evidence suggests that the unique modality of cell death is ...involved in the development and progression of several diseases including cancer, cardiovascular diseases (CVDs), neurodegenerative disorders,
etc.
However, the pathogenesis and signalling pathways of ferroptosis are not fully understood, possibly due to the lack of robust tools for the highly selective and sensitive imaging of ferroptosis analytes in complex living systems. Up to now, various small-molecule fluorescent probes have been applied as promising chemosensors for studying ferroptosis through tracking the biomolecules or microenvironment-related parameters
in vitro
and
in vivo
. In this review, we comprehensively reviewed the recent development of small-molecule fluorescent probes for studying ferroptosis, with a focus on the analytes, design strategies and bioimaging applications. We also provided new insights to overcome the major challenges in this emerging field.
Small-molecule fluorescent probes for studying ferroptosis.
Abstract
Most triple-negative breast cancer (TNBC) patients fail to respond to T cell-mediated immunotherapies. Unfortunately, the molecular determinants are still poorly understood. Breast cancer is ...the disease genetically linked to a deficiency in autophagy. Here, we show that autophagy defects in TNBC cells inhibit T cell-mediated tumour killing in vitro and in vivo. Mechanistically, we identify Tenascin-C as a candidate for autophagy deficiency-mediated immunosuppression, in which Tenascin-C is Lys63-ubiquitinated by Skp2, particularly at Lys942 and Lys1882, thus promoting its recognition by p62 and leading to its selective autophagic degradation. High Tenascin-C expression is associated with poor prognosis and inversely correlated with LC3B expression and CD8
+
T cells in TNBC patients. More importantly, inhibition of Tenascin-C in autophagy-impaired TNBC cells sensitizes T cell-mediated tumour killing and improves antitumour effects of single anti-PD1/PDL1 therapy. Our results provide a potential strategy for targeting TNBC with the combination of Tenascin-C blockade and immune checkpoint inhibitors.
Most patients with triple negative breast cancer (TNBC) do not respond to anti-PD1/PDL1 immunotherapy, indicating the necessity to explore immune checkpoint targets. B7H3 is a highly glycosylated ...protein. However, the mechanisms of B7H3 glycosylation regulation and whether the sugar moiety contributes to immunosuppression are unclear. Here, we identify aberrant B7H3 glycosylation and show that N-glycosylation of B7H3 at NXT motif sites is responsible for its protein stability and immunosuppression in TNBC tumors. The fucosyltransferase FUT8 catalyzes B7H3 core fucosylation at N-glycans to maintain its high expression. Knockdown of FUT8 rescues glycosylated B7H3-mediated immunosuppressive function in TNBC cells. Abnormal B7H3 glycosylation mediated by FUT8 overexpression can be physiologically important and clinically relevant in patients with TNBC. Notably, the combination of core fucosylation inhibitor 2F-Fuc and anti-PDL1 results in enhanced therapeutic efficacy in B7H3-positive TNBC tumors. These findings suggest that targeting the FUT8-B7H3 axis might be a promising strategy for improving anti-tumor immune responses in patients with TNBC.
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