2,3-Dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) is a stoichiometric oxidant that is frequently used in traditional organic synthesis. Recently, the rapid development of organic electrochemistry has led to new advancem...2,3-Dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) is a stoichiometric oxidant that is frequently used in traditional organic synthesis. Recently, the rapid development of organic electrochemistry has led to new advancements in DDQ-catalyzed C—H bonds functionalization. Moreover, the challenging C—H functionalization of electron-deficient arenes has been achieved through the merger of electrochemical DDQ catalysis and photoirradiation. In addition, the synthetic utility of electrophotochemical DDQ catalysis was further demonstrated by the nucleophilic aromatic substitution (SNAr) reaction of unactivated aryl fluorides. The recent developments in electro- and electrophotochemical DDQ-catalyzed C—H/C—F func- tionalizations with attention to their strategies and mechanistic insights are summarized. It is hoped that this not only deepens the understanding of this field, but also helps relevant researchers expand the application scope of DDQ catalysis.展开更多
BACKGROUND ATP-binding cassette subfamily B member 4(ABCB4)deficiency is associated with cholestatic liver disease primarily because of missense mutations,and many variants remain unidentified.Here,we validate the pat...BACKGROUND ATP-binding cassette subfamily B member 4(ABCB4)deficiency is associated with cholestatic liver disease primarily because of missense mutations,and many variants remain unidentified.Here,we validate the pathogenicity and mechanism of ABCB4 variants in clinical and in vitro trials,hypothesizing that these variants are responsible for impaired biliary function and contribute to the development of cholestatic liver diseases.AIM To clarify the functional features and pathogenicity of ABCB4 variants.METHODS Clinical data were collected from five patients with cholestatic liver disease that was initially not detected by routine examinations.Later,whole-exome sequencing confirmed ABCB4 variants and the patients were treated from January 2017 to December 2023.Pathogenic mechanisms were analyzed using bioinformatics tools,and a cell model in vitro was established to investigate ABCB4 mRNA expression,multidrug resistance protein 3(MDR3)expression,cellular localization,and phosphatidylcholine secretion.Results were compared using Student's t-tests.RESULTS Five missense variants(c.1757T>A,c.1865G>A,c.2362C>T,c.2777C>T and c.3250C>T),one intron variant(c.537-32G>T),and one synonymous(c.C504T)variant were identified.Three of the five patients had various degrees of cholestasis,two presented with liver cirrhosis,and all had elevated gamma-glutamyl transferase.Three of the four patients who underwent a liver biopsy had bile duct dilation,and one had gallstones.Two of the four patients had normal and reduced MDR3 immunohistochemical levels.Bioinformatic analysis indicated that these variants were likely pathogenic except c.C504T variant.None of the missense variants influenced subcellular MDR3 Localization in vitro.However,the c.1865G>A variant significantly decreased ABCB4 mRNA values,and all missense variants down-regulated phosphatidylcholine secretion.CONCLUSION This study uncovered new ABCB4 variants and emphasized the pathogenic potential of specific variants.The findings from five patients provided insight into the pathogenic mechanisms underlying ABCB4-related diseases.展开更多
This study systematically investigates the cyclization reaction mechanisms between n-C_(4)H_(3)(1-buten-3-yn-1-yl)and i-C_(4)H_(3)(2-buten-3-yn-1-yl)radicals with acetylene(C_(2)H_(2))using density functional theory(D...This study systematically investigates the cyclization reaction mechanisms between n-C_(4)H_(3)(1-buten-3-yn-1-yl)and i-C_(4)H_(3)(2-buten-3-yn-1-yl)radicals with acetylene(C_(2)H_(2))using density functional theory(DFT)and transition state theory(TST).The results reveal that the reaction of n-C_(4)H_(3)with acetylene proceeds via a radical chain mechanism through an additioncyclization pathway,yielding phenyl(sixmembered ring),fulvenyl(five-membered ring),and four-membered ring intermediates.The product formation rates follow the order:fulvenyl(five-membered ring)>phenyl(six-membered ring)>four-membered ring.For i-C_(4)H_(3),the intermediate structures depend on the carbon position of i-C_(4)H_(3)where acetylene addition occurs:addition at the C2 position predominantly generates fulvenyl(five-membered ring)as the primary product,whereas addition at the C4 position may lead to phenyl(six-membered ring),fulvenyl(five-membered ring),or four-membered ring intermediates,with the four-membered ring forming most rapidly and the six-membered ring the slowest.Theoretical analyses demonstrate that the selectivity of reaction pathways is primarily governed by structural differences between the isomers.This work provides atomic-scale insights into the cyclization processes between acetylene and C_(4)H_(3)species,establishing a foundation for refining models of soot precursor formation.展开更多
Phosphodiesterase 4 is a key enzyme involved in the regulation of cell signal transduction,but its role in subarachnoid hemorrhage remains unclear.Neuronal pyroptosis has been reported to be involved in early brain in...Phosphodiesterase 4 is a key enzyme involved in the regulation of cell signal transduction,but its role in subarachnoid hemorrhage remains unclear.Neuronal pyroptosis has been reported to be involved in early brain injury after subarachnoid hemorrhage.This study aimed to investigate whether phosphodiesterase 4 contributes to early brain injury after subarachnoid hemorrhage by mediating neuronal pyroptosis and its related mechanisms.Endovascular perforation of male C57BL/6J mice was performed to model subarachnoid hemorrhage in vivo,and oxyhemoglobin was added to the culture medium of primary neurons to model subarachnoid hemorrhage in vitro.A phosphodiesterase 4-specific inhibitor,etazolate,was intraperitoneally injected 30 minutes after subarachnoid hemorrhage induction.Small interfering RNA(siRNA)was administered intracerebroventricularly 72 hours before subarachnoid hemorrhage to achieve genetic knockdown of phosphodiesterase 4.To investigate the mechanism,a nucleotide-binding oligomerization domain-like receptor pyrin domain containing 3(NLRP3)-specific agonist,nigericin,was intracerebroventricularly injected 60 minutes before subarachnoid hemorrhage.Neuronal phosphodiesterase 4 expression increased after subarachnoid hemorrhage and reached the highest point at 24 hours.Etazolate treatment reduced neurological deficits and brain edema in mice,alleviated neuronal pyroptosis and inflammatory response,and improved neuronal injury.Treatment with phosphodiesterase 4 siRNA had the same neuroprotective effects as etazolate.Mechanistically,phosphodiesterase 4 triggered the nuclear factor kappa-B pathway,and simultaneously caused lysosomal and mitochondrial dysfunction after subarachnoid hemorrhage,which promoted NLRP3 inflammasome activation and induced neuronal pyroptosis.Blocking of phosphodiesterase 4 inhibited the nuclear factor kappa-B pathway,and improved lysosome and mitochondrial function.Activation of NLRP3 reversed the neuroprotective effects of etazolate without affecting phosphodiesterase 4 expression.Together,the results indicate that phosphodiesterase 4 regulates NLRP3-mediated neuronal pyroptosis in early brain injury after subarachnoid hemorrhage.Phosphodiesterase 4 may be a potential therapeutic molecular target for subarachnoid hemorrhage.展开更多
Neuromyelitis optica spectrum disorder-related optic neuritis involves various cellular responses to inflammation and degeneration.In most patients,the primary mechanism underlying neuromyelitis optica spectrum disord...Neuromyelitis optica spectrum disorder-related optic neuritis involves various cellular responses to inflammation and degeneration.In most patients,the primary mechanism underlying neuromyelitis optica spectrum disorder-related optic neuritis is the interaction of aquaporin-4 antibodies with the aquaporin-4 protein present on astrocytes within posterior optic nerve.This binding subsequently initiates a cascade of events leading to secondary demyelination of the optic nerve,ultimately culminating in optic nerve degeneration.Earlier studies on this disorder primarily used systemic-induced animal models,which often require prior activation of a systemic immune response.This can result in primary demyelination of the optic nerve,complicating the interpretation of experimental results.Such methodologies hinder the ability to isolate immune responses triggered by specific antibodies.Additionally,the lack of a detailed profile of disease progression over time limits our capacity to identify potential intervention windows.Therefore,constructing a targeted optic neuritis animal model induced by specific antibodies and elucidate the disease progression arecrucial for exploring the mechanisms underlying neuromyelitis optica spectrum disorder-related optic neuritis.In this study,specific antibodies against aquaporin-4 were precisely injected into the retrobulbar optic nerve of mice to induce a targeted inflammatory response in the posterior optic nerve,resulting in a more representative mouse model of neuromyelitis optica spectrum disorder-related optic neuritis than current models.The progression of the disease was then dynamically observed from both histological and functional perspectives over the course of 1 month following the induction of inflammation.By the first week,astrocytes were damaged,as evidenced by the loss of aquaporin-4 and glial fibrillary acidic protein,the activation of microglia,and the upregulation of microglia-related cytokines,including tumor necrosis factor,interleukin-6,interleukin-1β,C-X-C motif ligand 10,and brain-derived neurotrophic factor.Starting from the second week,there were signs of optic nerve demyelination and significant damage to axonal fibers and retinal ganglion cell bodies.Visual-evoked potentials and dark adaptation threshold responses in electroretinogram both indicated dysfunction in the visual pathway and retina,while optical coherence tomography revealed thinning of the retinal nerve fiber layer in live mice.In summary,in this study we conducted a dynamic exploration of the occurrence and progression of neuromyelitis optica spectrum disorder-related optic neuritis triggered by specific antibodies.Our results show pathological changes at various stages and correlate histological and molecular alterations with in vivo structural and functional deterioration.The findings from this study lay an important foundation for further research on neuromyelitis optica spectrum disorder-related optic neuritis.展开更多
文摘2,3-Dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) is a stoichiometric oxidant that is frequently used in traditional organic synthesis. Recently, the rapid development of organic electrochemistry has led to new advancements in DDQ-catalyzed C—H bonds functionalization. Moreover, the challenging C—H functionalization of electron-deficient arenes has been achieved through the merger of electrochemical DDQ catalysis and photoirradiation. In addition, the synthetic utility of electrophotochemical DDQ catalysis was further demonstrated by the nucleophilic aromatic substitution (SNAr) reaction of unactivated aryl fluorides. The recent developments in electro- and electrophotochemical DDQ-catalyzed C—H/C—F func- tionalizations with attention to their strategies and mechanistic insights are summarized. It is hoped that this not only deepens the understanding of this field, but also helps relevant researchers expand the application scope of DDQ catalysis.
基金Supported by the National Natural Science Foundation of China,No.81970454.
文摘BACKGROUND ATP-binding cassette subfamily B member 4(ABCB4)deficiency is associated with cholestatic liver disease primarily because of missense mutations,and many variants remain unidentified.Here,we validate the pathogenicity and mechanism of ABCB4 variants in clinical and in vitro trials,hypothesizing that these variants are responsible for impaired biliary function and contribute to the development of cholestatic liver diseases.AIM To clarify the functional features and pathogenicity of ABCB4 variants.METHODS Clinical data were collected from five patients with cholestatic liver disease that was initially not detected by routine examinations.Later,whole-exome sequencing confirmed ABCB4 variants and the patients were treated from January 2017 to December 2023.Pathogenic mechanisms were analyzed using bioinformatics tools,and a cell model in vitro was established to investigate ABCB4 mRNA expression,multidrug resistance protein 3(MDR3)expression,cellular localization,and phosphatidylcholine secretion.Results were compared using Student's t-tests.RESULTS Five missense variants(c.1757T>A,c.1865G>A,c.2362C>T,c.2777C>T and c.3250C>T),one intron variant(c.537-32G>T),and one synonymous(c.C504T)variant were identified.Three of the five patients had various degrees of cholestasis,two presented with liver cirrhosis,and all had elevated gamma-glutamyl transferase.Three of the four patients who underwent a liver biopsy had bile duct dilation,and one had gallstones.Two of the four patients had normal and reduced MDR3 immunohistochemical levels.Bioinformatic analysis indicated that these variants were likely pathogenic except c.C504T variant.None of the missense variants influenced subcellular MDR3 Localization in vitro.However,the c.1865G>A variant significantly decreased ABCB4 mRNA values,and all missense variants down-regulated phosphatidylcholine secretion.CONCLUSION This study uncovered new ABCB4 variants and emphasized the pathogenic potential of specific variants.The findings from five patients provided insight into the pathogenic mechanisms underlying ABCB4-related diseases.
基金Supported by the National Key Research and Development Program of China(2022YFB4301400)the Basic Science(Natural Science)Research Project for Higher Education Institutions in Jiangsu Province(24KJD580001)。
文摘This study systematically investigates the cyclization reaction mechanisms between n-C_(4)H_(3)(1-buten-3-yn-1-yl)and i-C_(4)H_(3)(2-buten-3-yn-1-yl)radicals with acetylene(C_(2)H_(2))using density functional theory(DFT)and transition state theory(TST).The results reveal that the reaction of n-C_(4)H_(3)with acetylene proceeds via a radical chain mechanism through an additioncyclization pathway,yielding phenyl(sixmembered ring),fulvenyl(five-membered ring),and four-membered ring intermediates.The product formation rates follow the order:fulvenyl(five-membered ring)>phenyl(six-membered ring)>four-membered ring.For i-C_(4)H_(3),the intermediate structures depend on the carbon position of i-C_(4)H_(3)where acetylene addition occurs:addition at the C2 position predominantly generates fulvenyl(five-membered ring)as the primary product,whereas addition at the C4 position may lead to phenyl(six-membered ring),fulvenyl(five-membered ring),or four-membered ring intermediates,with the four-membered ring forming most rapidly and the six-membered ring the slowest.Theoretical analyses demonstrate that the selectivity of reaction pathways is primarily governed by structural differences between the isomers.This work provides atomic-scale insights into the cyclization processes between acetylene and C_(4)H_(3)species,establishing a foundation for refining models of soot precursor formation.
基金supported by the National Natural Science Foundation of China,No.81870927(to ZH)the Natural Science Foundation Project ofChongqing Science and Technology Commission,No.CSTB2023NSCQ-MSX0112(to ZH).
文摘Phosphodiesterase 4 is a key enzyme involved in the regulation of cell signal transduction,but its role in subarachnoid hemorrhage remains unclear.Neuronal pyroptosis has been reported to be involved in early brain injury after subarachnoid hemorrhage.This study aimed to investigate whether phosphodiesterase 4 contributes to early brain injury after subarachnoid hemorrhage by mediating neuronal pyroptosis and its related mechanisms.Endovascular perforation of male C57BL/6J mice was performed to model subarachnoid hemorrhage in vivo,and oxyhemoglobin was added to the culture medium of primary neurons to model subarachnoid hemorrhage in vitro.A phosphodiesterase 4-specific inhibitor,etazolate,was intraperitoneally injected 30 minutes after subarachnoid hemorrhage induction.Small interfering RNA(siRNA)was administered intracerebroventricularly 72 hours before subarachnoid hemorrhage to achieve genetic knockdown of phosphodiesterase 4.To investigate the mechanism,a nucleotide-binding oligomerization domain-like receptor pyrin domain containing 3(NLRP3)-specific agonist,nigericin,was intracerebroventricularly injected 60 minutes before subarachnoid hemorrhage.Neuronal phosphodiesterase 4 expression increased after subarachnoid hemorrhage and reached the highest point at 24 hours.Etazolate treatment reduced neurological deficits and brain edema in mice,alleviated neuronal pyroptosis and inflammatory response,and improved neuronal injury.Treatment with phosphodiesterase 4 siRNA had the same neuroprotective effects as etazolate.Mechanistically,phosphodiesterase 4 triggered the nuclear factor kappa-B pathway,and simultaneously caused lysosomal and mitochondrial dysfunction after subarachnoid hemorrhage,which promoted NLRP3 inflammasome activation and induced neuronal pyroptosis.Blocking of phosphodiesterase 4 inhibited the nuclear factor kappa-B pathway,and improved lysosome and mitochondrial function.Activation of NLRP3 reversed the neuroprotective effects of etazolate without affecting phosphodiesterase 4 expression.Together,the results indicate that phosphodiesterase 4 regulates NLRP3-mediated neuronal pyroptosis in early brain injury after subarachnoid hemorrhage.Phosphodiesterase 4 may be a potential therapeutic molecular target for subarachnoid hemorrhage.
基金The study was partially supported by the General Research Fund(GRF)from the Research Grants Council(RGC)of the Hong Kong Special Administrative Region,China,No.15103522(to ST)the Internal Research Grant from the Hong Kong Polytechnic University 2021-23,No.P0035512(to ST)and P0035375(to HHLC)+1 种基金the Innovation and Technology Commission of the Hong Kong Special Administrative Region(ITC InnoHK CEVR Project)The Hong Kong Polytechnics University Research Center for Sharp Vision,No.P0039595.
文摘Neuromyelitis optica spectrum disorder-related optic neuritis involves various cellular responses to inflammation and degeneration.In most patients,the primary mechanism underlying neuromyelitis optica spectrum disorder-related optic neuritis is the interaction of aquaporin-4 antibodies with the aquaporin-4 protein present on astrocytes within posterior optic nerve.This binding subsequently initiates a cascade of events leading to secondary demyelination of the optic nerve,ultimately culminating in optic nerve degeneration.Earlier studies on this disorder primarily used systemic-induced animal models,which often require prior activation of a systemic immune response.This can result in primary demyelination of the optic nerve,complicating the interpretation of experimental results.Such methodologies hinder the ability to isolate immune responses triggered by specific antibodies.Additionally,the lack of a detailed profile of disease progression over time limits our capacity to identify potential intervention windows.Therefore,constructing a targeted optic neuritis animal model induced by specific antibodies and elucidate the disease progression arecrucial for exploring the mechanisms underlying neuromyelitis optica spectrum disorder-related optic neuritis.In this study,specific antibodies against aquaporin-4 were precisely injected into the retrobulbar optic nerve of mice to induce a targeted inflammatory response in the posterior optic nerve,resulting in a more representative mouse model of neuromyelitis optica spectrum disorder-related optic neuritis than current models.The progression of the disease was then dynamically observed from both histological and functional perspectives over the course of 1 month following the induction of inflammation.By the first week,astrocytes were damaged,as evidenced by the loss of aquaporin-4 and glial fibrillary acidic protein,the activation of microglia,and the upregulation of microglia-related cytokines,including tumor necrosis factor,interleukin-6,interleukin-1β,C-X-C motif ligand 10,and brain-derived neurotrophic factor.Starting from the second week,there were signs of optic nerve demyelination and significant damage to axonal fibers and retinal ganglion cell bodies.Visual-evoked potentials and dark adaptation threshold responses in electroretinogram both indicated dysfunction in the visual pathway and retina,while optical coherence tomography revealed thinning of the retinal nerve fiber layer in live mice.In summary,in this study we conducted a dynamic exploration of the occurrence and progression of neuromyelitis optica spectrum disorder-related optic neuritis triggered by specific antibodies.Our results show pathological changes at various stages and correlate histological and molecular alterations with in vivo structural and functional deterioration.The findings from this study lay an important foundation for further research on neuromyelitis optica spectrum disorder-related optic neuritis.
