Human pluripotent stem cells represent a potentially unlimited source of functional pancreatic endocrine lineage cells. Here we report a highly efficient approach to induce human embryonic stem （ES） cells and induce...Human pluripotent stem cells represent a potentially unlimited source of functional pancreatic endocrine lineage cells. Here we report a highly efficient approach to induce human embryonic stem （ES） cells and induced pluripo- tent stem （iPS） cells to differentiate into mature insulin-producing cells in a chemical-defined culture system. The differentiated human ES cells obtained by this approach comprised nearly 25% insulin-positive cells as assayed by flow cytometry analysis, which released insulin/C-peptide in response to glucose stimuli in a manner comparable to that of adult human islets. Most of these insulin-producing cells co-expressed mature β cell-specific markers such as NKX6-1 and PDX1, indicating a similar gene expression pattern to adult islet β cells in vivo. In this study, we also demonstrated that EGF facilitates the expansion of PDXl-positive pancreatic progenitors. Moreover, our protocol also succeeded in efficiently inducing human iPS cells to differentiate into insuIin-producing ceils. Therefore, this work not only provides a new model to study the mechanism of human pancreatic specialization and maturation in vitro, but also enhances the possibility of utilizing patient-specific iPS cells for the treatment of diabetes.展开更多
The capacity for self-renewal and differentiation of human embryonic stem （ES） cells makes them a potential source for generation of pancreatic beta cells for treating type I diabetes mellitus. Here, we report a new...The capacity for self-renewal and differentiation of human embryonic stem （ES） cells makes them a potential source for generation of pancreatic beta cells for treating type I diabetes mellitus. Here, we report a newly developed and effective method, carried out in a serum-free system, which induced human ES cells to differentiate into insulin-producing cells. Activin A was used in the initial stage to induce definitive endoderm differentiation from human ES cells, as detected by the expression of the definitive endoderm markers Sox17 and Brachyury. Further, all-trans retinoic acid （RA） was used to promote pancreatic differentiation, as indicated by the expression of the early pancreatic transcription factors pdxl and hlxb9. After maturation in DMEM/F12 serum-free medium with bFGF and nicotinamide, the differentiated cells expressed islet specific markers such as C-peptide, insulin, glucagon and glut2. The percentage of C-peptide-positive cells exceeded 15%. The secretion of insulin and C-peptide by these cells corresponded to the variations in glucose levels. When transplanted into renal capsules of Streptozotocin （STZ）-treated nude mice, these differentiated human ES cells survived and maintained the expression of beta cell marker genes, including C-peptide, pdxl, glucokinase, nkx6.1, lAPP, pax6 and Tcfl. Thirty percent of the transplanted nude mice exhibited apparent restoration of stable euglycemia; and the corrected phenotype was sustained for more than six weeks. Our new method provides a promising in vitro differentiation model for studying the mechanisms of human pancreas development and illustrates the potential of using human ES cells for the treatment of type I diabetes mellitus.展开更多
OBJECTIVE Previous studies have demonstrated a close association between an altered immune system and major depressive disorders,and inhibition of neuroinflammation may represent an alternative mechanism to treat depr...OBJECTIVE Previous studies have demonstrated a close association between an altered immune system and major depressive disorders,and inhibition of neuroinflammation may represent an alternative mechanism to treat depression.Recently,the anti-inflammatory activ⁃ity of ibrutinib has been reported.However,the effect of ibrutinib on neuroinflammation-induced depression and its underlying mechanism has not been comprehensively studied.Therefore,we aimed to elucidate the potential anti-depres⁃sive role and mechanism of ibrutinib against neu⁃roinflammation-induced depression and synaptic defects.METHODS AND RESULTS Ibrutinib treatment significantly reduced lipopolysaccha⁃ride(LPS)-induced depressive-like behaviors and neuroinflammation via inhibiting NF-κB acti⁃vation,decreasing proinflammatory cytokine levels,and normalizing redox signaling and its downstream components,including Nrf2,HO-1,and SOD2,as well as glial cell activation mark⁃ers,such as Iba-1 and GFAP.Further,ibrutinib treatment inhibited LPS-activated inflammasome activation by targeting NLRP3/P38/caspase-1 signaling.Interestingly,LPS reduced the number of dendritic spines and expression of BDNF,and synaptic-related markers,including PSD95,snap25,and synaptophysin,were improved by ibrutinib treatment in the hippocampal area of the mouse brain.CONCLUSION Ibrutinib can allevi⁃ate neuroinflammation and synaptic defects,sug⁃gesting it has antidepressant potential against LPS-induced neuroinflammation and depression.展开更多
As a critical apoptosis executioner, caspase-3 becomes activated and then enters into the nucleus to exert its function. However, the molecular mechanism of this nuclear entry of active caspase-3 is still unknown. In ...As a critical apoptosis executioner, caspase-3 becomes activated and then enters into the nucleus to exert its function. However, the molecular mechanism of this nuclear entry of active caspase-3 is still unknown. In this study, we revealed that easpase-3 harbors a crm-l-independent nuclear export signal （NES） in its small subunit. Using reversecaspase-3 as the study model, we found that the function of the NES in caspase-3 was not disturbed by the conformational changes during induced caspase-3 activation. Mutations disrupting the cleavage activity or p3-recognition site resulted in a defect in the nuclear entry of active caspase-3. We provide evidence that the p3-mediated specific cleavage activity of active caspase-3 abrogated the function of the NES. In conclusion, our results demonstrate that during caspase-3 activation, NES is constitutively present, p3-mediated specific cleavage activity abrogates the NES function in caspase-3, thus facilitating the nuclear entry of active caspase-3.展开更多
Purine nucleoside phosphorylase is a key enzyme in the purine-salvage pathway and an attractive target for drug design. The crystal structure of Streptococcus mutants purine nucleoside phosphorylase（Smu PNP） has bee...Purine nucleoside phosphorylase is a key enzyme in the purine-salvage pathway and an attractive target for drug design. The crystal structure of Streptococcus mutants purine nucleoside phosphorylase（Smu PNP） has been solved by molecular replacement at 1.80 resolution and refined to R factors of 19.9%/23.7%（Rcryst/Rfree） . Sequence alignment and structural comparison show that Smu PNP has more similarity with PNPs isolated from human and malarial sources than the bacterial PNPs. The structure complexed with hypoxanthine（HPA） and sulfate ion was solved at 2.24A resolution and refined to R factors of 21.6%/24.1%（Rcryst/Rfree） . It is interesting to note that the resulting electron density indicated the product,HPA,presents in the active site although inosine was included in the crystallization mixture with Smu PNP. Asn233 and Glu191 are the important residues for ligand binding and recognition. Comparison with PNPs from different species gives detailed information about binding of small molecules on the active site,which is important for the studies of enzymatic mechanism and rational design of specific inhibitors for PNPs.展开更多
Unnatural amino acids(UAAs)have gained significant attention in protein engineering and drug development owing to their ability to introduce new chemical functionalities to proteins.In eukaryotes,genetic code expansio...Unnatural amino acids(UAAs)have gained significant attention in protein engineering and drug development owing to their ability to introduce new chemical functionalities to proteins.In eukaryotes,genetic code expansion(GCE)enables the incorporation of UAAs and facilitates posttranscriptional modification(PTM),which is not feasible in prokaryotic systems.GCE is also a powerful tool for cell or animal imaging,the monitoring of protein interactions in target cells,drug development,and switch regulation.Therefore,there is keen interest in utilizing GCE in eukaryotic systems.This review provides an overview of the application of GCE in eukaryotic systems and discusses current challenges that need to be addressed.展开更多
PTEN, a negative regulator of the phosphatidylinositol-3-kinase/AKT pathway, is an important modulator of insulin signaling. To determine the metabolic function of pancreatic Pten, we generated pancreas-specific Pten ...PTEN, a negative regulator of the phosphatidylinositol-3-kinase/AKT pathway, is an important modulator of insulin signaling. To determine the metabolic function of pancreatic Pten, we generated pancreas-specific Pten knockout （PPKO） mice. PPKO mice had enlarged pancreas and elevated proliferation of acinar cells. They also exhibited hypoglycemia, hypoinsulinemia, and altered amino metabolism. Notably, PPKO mice showed delayed onset of streptozotocin （STZ）-induced diabetes and sex-biased resistance to high-fat-diet （HFD）-induced diabetes. To investigate the mechanism for the resistance to HFD-induced hyperglycemia in PPKO mice, we evaluated AKT phosphorylation in major insulin-responsive tissues： the liver, muscle, and fat. We found that Pten loss in the pancreas causes the elevation of AKT signaling in the liver. The phosphorylation of AKT and its downstream substrate GSK3β was increased in the liver of PPKO mice, while PTEN level was decreased without detectable excision of Pten allele in the liver of PPKO mice. Proteomics analysis revealed dramatically decreased level of 78-kDa glucose-regulated protein （GRP78） in the liver of PPKO mice, which may also contribute to the lower blood glucose level of PPKO mice fed with HFD. Together, our findings reveal a novel response in the liver to pancreatic defect in metabolic regulation, adding a new dimension to understanding diabetes resistance.展开更多
A cobalt-catalyzed ring-opening/hydroxylation cascade of highly strained cyclopropanols has been developed for the first time. The reaction was conducted under open-air atmosphere to afford a broad series of structura...A cobalt-catalyzed ring-opening/hydroxylation cascade of highly strained cyclopropanols has been developed for the first time. The reaction was conducted under open-air atmosphere to afford a broad series of structurally diverse β-hydroxy ketones in moderate to good yields with high regioselectivity.The protocol features mild reaction conditions, simple operation, high-functional-group tolerance, facile scalability, and heterocycle compatibility.展开更多
Histone H2A methylation at Glnl04 （H2AQ104Me） is a new type of histone post-translational modification （PTM） discovered recently. This modification has been found to have significant influence on gene transcriptio...Histone H2A methylation at Glnl04 （H2AQ104Me） is a new type of histone post-translational modification （PTM） discovered recently. This modification has been found to have significant influence on gene transcription. However, the structural and fimctional consequence of glutamine methylation on nucleosome remains to be further elucidated. Obtaining of histones with site-specific methylation at glutamine residues might facilitate the studies towards a better understanding of this new PTM. In the present work, total chemical synthesis of H2AQ 104Me was carried out through use of the hydrazide-based native chemical ligation. Synthetic histone H2AQ104Me could be successfully incorporated into nucleosomes in vitro and showed a negative influence on the nucleosome stability.展开更多
Radiotherapy is widely used in the management of advanced colorectal cancer(CRC).However,the clinical efficacy is limited by the safe irradiated dose.Sensitizing tumor cells to radiotherapy via interrupting DNA repair...Radiotherapy is widely used in the management of advanced colorectal cancer(CRC).However,the clinical efficacy is limited by the safe irradiated dose.Sensitizing tumor cells to radiotherapy via interrupting DNA repair is a promising approach to conquering the limitation.The BRCA1-BARD1 complex has been demonstrated to play a critical role in homologous recombination(HR)DSB repair,and its functions may be affected by HERC2 or BAP1.Accumulated evidence illustrates that the ubiquitination-deubiquitination balance is involved in these processes;however,the precise mechanism for the cross-talk among these proteins in HR repair following radiation hasn’t been defined.Through activity-based profiling,we identified PT33 as an active entity for HR repair suppression.Subsequently,we revealed that BAP1 serves as a novel molecular target of PT33 via a CRISPR-based deubiquitinase screen.Mechanistically,pharmacological covalent inhibition of BAP1 with PT33 recruits HERC2 to compete with BARD1 for BRCA1 interaction,interrupting HR repair.Consequently,PT33 treatment can substantially enhance the sensitivity of CRC cells to radiotherapy in vitro and in vivo.Overall,these findings provide a mechanistic basis for PT33-induced HR suppression and may guide an effective strategy to improve therapeutic gain.展开更多
Enantioselective domino alkenylation-alkynylation of olefins is achieved for the first time,using terminal alkynes directly as pronucleophiles.The new reaction enables facile construction of azacycles carrying quatern...Enantioselective domino alkenylation-alkynylation of olefins is achieved for the first time,using terminal alkynes directly as pronucleophiles.The new reaction enables facile construction of azacycles carrying quaternary stereocenters,including 5–7 membered pyrrolidines,piperidines and tetrahydroazepines.Moreover,alkynyl groups in azacyclic products provide a useful handle for derivatization that formed both fused and bridged azabicycles.展开更多
Targeted genome modifications with the Cas9/gRNA system derived from the clustered regularly interspaced short palin- dromic repeat/CRISPR-associated （CRISPR/Cas） system have been successfully used in cultured human...Targeted genome modifications with the Cas9/gRNA system derived from the clustered regularly interspaced short palin- dromic repeat/CRISPR-associated （CRISPR/Cas） system have been successfully used in cultured human cells as well as in most model organisms, including zebrafish （Danio rerio）, mouse, and fruit fly （Chang et al., 2013; Cong et al., 2013; Gratz et al., 2013; Hwang et al., 2013; Jao et al., 2013; Shen et al., 2013; Wei et al., 2013）. Its application in zebrafish is particu- larly attractive due to the ease of handling this organism and the simple application of this method by direct injection of Cas9/ gRNA. However, the information about its specificity in this organism is very limited and needs further evaluation. In addition, it is conceivable that a Cas9 mRNA optimized for zebrafish codon preference could enhance its activity.展开更多
Ca2＋ signals participate in various cellular processes with spatial and temporal dynamics, among which, inositol 1,4,5-trisphosphate receptors （IP3Rs）-mediated Ca2＋ signals are essential for early development. How...Ca2＋ signals participate in various cellular processes with spatial and temporal dynamics, among which, inositol 1,4,5-trisphosphate receptors （IP3Rs）-mediated Ca2＋ signals are essential for early development. However, the underlying mechanisms of IP3R- regulated cell fate decision remain largely unknown. Here we report that IP3Rs are required for the hematopoietic and cardiac fate divergence of mouse embryonic stem cells （mESCs）. Deletion of IP3Rs （IP3R-tKO） reduced FIkl＋/PDGFRα- hematopoietic mesoderm, c-Kit＋/CD41＋ hematopoietic progenitor ceil population, and the colony-forming unit activity, but increased cardiac progenitor markers as well as cardiomyocytes. Concomitantly, the expression of a key regulator of hematopoiesis, Ely2, was reduced in IP3R-tKO cells, which could be rescued by the activation of Ca2＋ signals and calcineurin or overexpression of constitutively active form of NFATc3. Furthermore, IP3R-tKO impaired specific targeting of Ely2 by NFATc3 via its evolutionarily conserved cis-element in differentiating ESCs. Importantly, the activation of Ca2＋-calcineurin-NFAT pathway reversed the phenotype of IP3R-tKO cells. These findings reveal an unrecognized governing role of IP3Rs in hematopoietic and cardiac fate commitment via IP3Rs-Ca2＋-calcineurin-NFATc3- Etv2 pathway.展开更多
Ubiquitin(Ub) chain isopeptide bond mimics are useful molecules for biochemical and biophysical studies. Herein, we report the semi-synthesis of the disulfide-linked K11/K48-branched tri-Ub(Ub_3^(11/48)(S-S)), the fir...Ubiquitin(Ub) chain isopeptide bond mimics are useful molecules for biochemical and biophysical studies. Herein, we report the semi-synthesis of the disulfide-linked K11/K48-branched tri-Ub(Ub_3^(11/48)(S-S)), the first example of an isopeptide mimic for the branched Ub chains,which have recently emerged as an interesting category of Ub modifications. Our strategy comprised the El-dependent synthesis of the Ub conjugate of aminoethanethiol, followed by disulfide formation with Ub(K11 C, K48 C). The structure of the synthetic isopeptide bond mimics was verified by the crystal structure of Ub_3^(11/48)(S-S). Deubiquitination and pulldown assays indicated that the synthetic Ub_3^(11/48)(S-S) could be hydrolyzed by linkage-specific deubiquitinases(K11-specific Cezanne and K48-specific OTUB1), and recognized by proteasomal ubiquitin receptor S5 a.展开更多
A unified strategy toward the construction of the [5.7.6]tricyclic skeleton of liphagal is reported,featuring InCl3-mediated intramolecular Friedel-Crafts-type cyclization.
Direct functionalization of inert C(sp^(3))–H bonds in pharmaceutically significant compounds is very important in modern synthetic organic chemistry.In this article,we disclose a practical and efficient method for t...Direct functionalization of inert C(sp^(3))–H bonds in pharmaceutically significant compounds is very important in modern synthetic organic chemistry.In this article,we disclose a practical and efficient method for the oxidative lactonization of benzylic C(sp^(3))–H bonds enabled by the synergistic interactions of organic dye-type rose bengal,n-Bu_(4)N∙Br,O_(2) and Na_(2)HPO_(4) under visible light irradiation.This reaction does not require transition metal catalysts or strong oxidants.A range of structurally diverse phthalides has been synthesized with excellent selectivity and high functional group compatibility.The late-stage application of this reaction to the preparation of structurally complex phthalides demonstrates its synthetic utility.展开更多
One major strategy to generate genetically modified mouse models is gene targeting in mouse embryonic stem(ES)cells,which is used to produce gene-targeted mice for wide applications in biomedicine.However,a major bott...One major strategy to generate genetically modified mouse models is gene targeting in mouse embryonic stem(ES)cells,which is used to produce gene-targeted mice for wide applications in biomedicine.However,a major bottleneck in this approach is that the robustness of germiine transmission of gene-targeted ES cells can be significantly reduced by their genetic and epigenetic instability after long-term culturing,which impairs the efficiency and robustness of mouse model generation.Recently,we have established a new type of pluripotent cells termed extended pluripotent stem(EPS)cells,which have superior developmental potency and robust germline competence compared to conventional mouse ES cells.In this study,we demonstrate that mouse EPS cells well maintain developmental potency and genetic stability after long-term passage.Based on gene targeting in mouse EPS cells,we established a new approach to directly and rapidly generate gene-targeted mouse models through tetraploid complementation,Haibo Li and Chaoran Zhao contributed equally to this work.Electronic supplementary material The online version of this article(https://doi.org/10.1007/s13238-018-0556-1)contains supplementary material,which is available to authorized users.which could be accomplished in approximately 2 months.Importantly,using this approach,we successfully constructed mouse models in which the human interleukin 3(IL3)or interleukin 6(IL6)gene was knocked into its corresponding locus in the mouse genome.Our study demonstrates the feasibility of using mouse EPS cells to rapidly generate mouse models by gene targeting,which have great application potential in biomedical research.展开更多
of main observation and conclusion We have achieved the total synthesis of an architecturally and biologically intriguing cyclic polypeptide,rhizonin A(1);in an exceptionally concise and convergent fashion.The strateg...of main observation and conclusion We have achieved the total synthesis of an architecturally and biologically intriguing cyclic polypeptide,rhizonin A(1);in an exceptionally concise and convergent fashion.The strategic route entails 9 longest linear steps to elaborate commercially available materials into the natural product with an overall yield of 9.7%.The brevity of sequence and high overall yield was fueled by the judicious selection of chemical tactics.Rhizonin A(1)showed weak inhibitory effects on the cell viability of HCT116 colorectal cancer cells and this activity was dependent on hypoxia-inducible factors.展开更多
Background:Notch is one of the most important signaling pathways involved in cell fate determination.Activation of the Notch pathway requires the binding of a membrane-bound ligand to the Notch receptor in the adjacen...Background:Notch is one of the most important signaling pathways involved in cell fate determination.Activation of the Notch pathway requires the binding of a membrane-bound ligand to the Notch receptor in the adjacent cell which induces proteolytic cleavages and the activation of the receptor.A unique feature of the Notch signaling is that processes such as modification,endocytosis or recycling of the ligand have been reported to play critical roles during Notch signaling,however,the underlying molecular mechanism appears context-dependent and often controversial.Results:Here we identified SNX17 as a novel regulator of the Notch pathway.SNX17 is a sorting nexin family protein implicated in vesicular trafficking and we find it is specifically required in the ligand-expressing cells for Notch signaling.Mechanistically,SNX17 regulates the protein level of Jag1a on plasma membrane by binding to Jag1a and facilitating the retromer-dependent recycling of the ligand.In zebrafish,inhibition of this SNX17-mediated Notch signaling pathway results in defects in neurogenesis as well as pancreas development.Conclusions:Our results reveal that SNX17,by acting as a cargo-specific adaptor,promotes the retromer dependent recycling of Jag1a and Notch signaling and this pathway is involved in cell fate determination during zebrafish neurogenesis and pancreas development.展开更多
In this paper,we report the concise total syntheses of three botryane sesquiterpenoids:dehydrobotrydienal,dehydrobotrydienol,and 10-oxodehydrodihydrobotrydial.The key transformations include tandem Co-tetramethylthiou...In this paper,we report the concise total syntheses of three botryane sesquiterpenoids:dehydrobotrydienal,dehydrobotrydienol,and 10-oxodehydrodihydrobotrydial.The key transformations include tandem Co-tetramethylthiourea-catalyzed Pauson–Khand and 6π-electrocyclization reactions to forge the tricyclic core structure of the botryanes,and further oxidative aromatization and oxidation to complete the total syntheses.展开更多
文摘Human pluripotent stem cells represent a potentially unlimited source of functional pancreatic endocrine lineage cells. Here we report a highly efficient approach to induce human embryonic stem （ES） cells and induced pluripo- tent stem （iPS） cells to differentiate into mature insulin-producing cells in a chemical-defined culture system. The differentiated human ES cells obtained by this approach comprised nearly 25% insulin-positive cells as assayed by flow cytometry analysis, which released insulin/C-peptide in response to glucose stimuli in a manner comparable to that of adult human islets. Most of these insulin-producing cells co-expressed mature β cell-specific markers such as NKX6-1 and PDX1, indicating a similar gene expression pattern to adult islet β cells in vivo. In this study, we also demonstrated that EGF facilitates the expansion of PDXl-positive pancreatic progenitors. Moreover, our protocol also succeeded in efficiently inducing human iPS cells to differentiate into insuIin-producing ceils. Therefore, this work not only provides a new model to study the mechanism of human pancreatic specialization and maturation in vitro, but also enhances the possibility of utilizing patient-specific iPS cells for the treatment of diabetes.
基金This research was supported by the Ministry of Science and Technology Grant （2001CB510106）；Science and Technology Plan of Beijing Municipal Government （H020220050290）；National Natural Science Foundation of China Awards for 0utstanding Young Scientists （30125022）；for Creative Research Groups （30421004）；Bill ＆ Melinda Gates Foundation Grant （37871） to H Deng.
文摘The capacity for self-renewal and differentiation of human embryonic stem （ES） cells makes them a potential source for generation of pancreatic beta cells for treating type I diabetes mellitus. Here, we report a newly developed and effective method, carried out in a serum-free system, which induced human ES cells to differentiate into insulin-producing cells. Activin A was used in the initial stage to induce definitive endoderm differentiation from human ES cells, as detected by the expression of the definitive endoderm markers Sox17 and Brachyury. Further, all-trans retinoic acid （RA） was used to promote pancreatic differentiation, as indicated by the expression of the early pancreatic transcription factors pdxl and hlxb9. After maturation in DMEM/F12 serum-free medium with bFGF and nicotinamide, the differentiated cells expressed islet specific markers such as C-peptide, insulin, glucagon and glut2. The percentage of C-peptide-positive cells exceeded 15%. The secretion of insulin and C-peptide by these cells corresponded to the variations in glucose levels. When transplanted into renal capsules of Streptozotocin （STZ）-treated nude mice, these differentiated human ES cells survived and maintained the expression of beta cell marker genes, including C-peptide, pdxl, glucokinase, nkx6.1, lAPP, pax6 and Tcfl. Thirty percent of the transplanted nude mice exhibited apparent restoration of stable euglycemia; and the corrected phenotype was sustained for more than six weeks. Our new method provides a promising in vitro differentiation model for studying the mechanisms of human pancreas development and illustrates the potential of using human ES cells for the treatment of type I diabetes mellitus.
文摘OBJECTIVE Previous studies have demonstrated a close association between an altered immune system and major depressive disorders,and inhibition of neuroinflammation may represent an alternative mechanism to treat depression.Recently,the anti-inflammatory activ⁃ity of ibrutinib has been reported.However,the effect of ibrutinib on neuroinflammation-induced depression and its underlying mechanism has not been comprehensively studied.Therefore,we aimed to elucidate the potential anti-depres⁃sive role and mechanism of ibrutinib against neu⁃roinflammation-induced depression and synaptic defects.METHODS AND RESULTS Ibrutinib treatment significantly reduced lipopolysaccha⁃ride(LPS)-induced depressive-like behaviors and neuroinflammation via inhibiting NF-κB acti⁃vation,decreasing proinflammatory cytokine levels,and normalizing redox signaling and its downstream components,including Nrf2,HO-1,and SOD2,as well as glial cell activation mark⁃ers,such as Iba-1 and GFAP.Further,ibrutinib treatment inhibited LPS-activated inflammasome activation by targeting NLRP3/P38/caspase-1 signaling.Interestingly,LPS reduced the number of dendritic spines and expression of BDNF,and synaptic-related markers,including PSD95,snap25,and synaptophysin,were improved by ibrutinib treatment in the hippocampal area of the mouse brain.CONCLUSION Ibrutinib can allevi⁃ate neuroinflammation and synaptic defects,sug⁃gesting it has antidepressant potential against LPS-induced neuroinflammation and depression.
基金Supplementary information is linked to the online version of the paper on the Cell Research website.Acknowledgments We thank Prof Jian Wang （Shanghai University, Shanghai） for his valuable revision and discussion. This work was supported by grants from the National Natural Science Foundation of China （30700411）, Shenzhen Bureau of Science Technology and Information （SZKJ-2006018, SZKJ-2007012）, Shenzhen Nanshan Bureau of Science Technology and Information （2008036） and Shenzhen Key Laboratory Advancement Scheme.
文摘As a critical apoptosis executioner, caspase-3 becomes activated and then enters into the nucleus to exert its function. However, the molecular mechanism of this nuclear entry of active caspase-3 is still unknown. In this study, we revealed that easpase-3 harbors a crm-l-independent nuclear export signal （NES） in its small subunit. Using reversecaspase-3 as the study model, we found that the function of the NES in caspase-3 was not disturbed by the conformational changes during induced caspase-3 activation. Mutations disrupting the cleavage activity or p3-recognition site resulted in a defect in the nuclear entry of active caspase-3. We provide evidence that the p3-mediated specific cleavage activity of active caspase-3 abrogated the function of the NES. In conclusion, our results demonstrate that during caspase-3 activation, NES is constitutively present, p3-mediated specific cleavage activity abrogates the NES function in caspase-3, thus facilitating the nuclear entry of active caspase-3.
基金Supported by the National Natural Science Foundation of China (30530190 to XDS and 30700115 to NY)
文摘Purine nucleoside phosphorylase is a key enzyme in the purine-salvage pathway and an attractive target for drug design. The crystal structure of Streptococcus mutants purine nucleoside phosphorylase（Smu PNP） has been solved by molecular replacement at 1.80 resolution and refined to R factors of 19.9%/23.7%（Rcryst/Rfree） . Sequence alignment and structural comparison show that Smu PNP has more similarity with PNPs isolated from human and malarial sources than the bacterial PNPs. The structure complexed with hypoxanthine（HPA） and sulfate ion was solved at 2.24A resolution and refined to R factors of 21.6%/24.1%（Rcryst/Rfree） . It is interesting to note that the resulting electron density indicated the product,HPA,presents in the active site although inosine was included in the crystallization mixture with Smu PNP. Asn233 and Glu191 are the important residues for ligand binding and recognition. Comparison with PNPs from different species gives detailed information about binding of small molecules on the active site,which is important for the studies of enzymatic mechanism and rational design of specific inhibitors for PNPs.
基金This work was supported by the National Key R&D Program of China(Nos.2019YFA0904200 and 2019YFA0906100)the National Natural Science Foundation of China(No.32171464)Shenzhen Science and Technology Innovation Program(JCYJ20180504165501371).
文摘Unnatural amino acids(UAAs)have gained significant attention in protein engineering and drug development owing to their ability to introduce new chemical functionalities to proteins.In eukaryotes,genetic code expansion(GCE)enables the incorporation of UAAs and facilitates posttranscriptional modification(PTM),which is not feasible in prokaryotic systems.GCE is also a powerful tool for cell or animal imaging,the monitoring of protein interactions in target cells,drug development,and switch regulation.Therefore,there is keen interest in utilizing GCE in eukaryotic systems.This review provides an overview of the application of GCE in eukaryotic systems and discusses current challenges that need to be addressed.
基金This research was supported by grants from the Ministry of Ed- ucation （705001）, National Basic Research Program of China （973 Program 2009CB941200）, National Natural Science Foundation of China （30830061 and 30421004）, and a 111 project to H Deng. We thank Dr Tak Wah Mak （University of Alberta, Canada） for kindly providing the Ptern mice, Dr Guoqiang Gu （Vanderbilt University, USA） for kindly providing the plasmid of Pdxl-Cre, and Dr C Wright （Vanderbilt University, USA） for the PDX1 antibody. We thank the Model Animal Research Center of Nanjing University for B6 129-Gt（ROSA）26Sor tm/Sho/J mice and the Research Center for Proteome Analysis for proteomics analysis. We thank Dr Matt Stremlau, Dr Hui Zhang, Jun Cai, Han Qin, Jian Li, Yan Shi, Haisheng Zhou, and Fei Ye for their critical reading of the manu- script. We also thank Wei Jiang, Yushan Guo, Jie Yang, Chengyan Wang, Hui Zhang, and other colleagues in our laboratory for providing technical assistance and advice during the experiments.
文摘PTEN, a negative regulator of the phosphatidylinositol-3-kinase/AKT pathway, is an important modulator of insulin signaling. To determine the metabolic function of pancreatic Pten, we generated pancreas-specific Pten knockout （PPKO） mice. PPKO mice had enlarged pancreas and elevated proliferation of acinar cells. They also exhibited hypoglycemia, hypoinsulinemia, and altered amino metabolism. Notably, PPKO mice showed delayed onset of streptozotocin （STZ）-induced diabetes and sex-biased resistance to high-fat-diet （HFD）-induced diabetes. To investigate the mechanism for the resistance to HFD-induced hyperglycemia in PPKO mice, we evaluated AKT phosphorylation in major insulin-responsive tissues： the liver, muscle, and fat. We found that Pten loss in the pancreas causes the elevation of AKT signaling in the liver. The phosphorylation of AKT and its downstream substrate GSK3β was increased in the liver of PPKO mice, while PTEN level was decreased without detectable excision of Pten allele in the liver of PPKO mice. Proteomics analysis revealed dramatically decreased level of 78-kDa glucose-regulated protein （GRP78） in the liver of PPKO mice, which may also contribute to the lower blood glucose level of PPKO mice fed with HFD. Together, our findings reveal a novel response in the liver to pancreatic defect in metabolic regulation, adding a new dimension to understanding diabetes resistance.
基金State Key Basic Research Program of the People's Republic of China(No.2018YFC0310900)National Natural Science Foundation of China(Nos.21871018,21732001)+9 种基金Shenzhen Science and Technology Innovation Committee(Nos.KQTD20190929174023858,JCYJ20180504165454447)Industry and Information Technology Bureau of Shenzhen Municipality(No.201806151622209330)Guangdong Science and Technology Program(No.2017B030314002)Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions(No.2019SHIBS0004)the National Ten Thousand Talent Program(the Leading Talent Tier)for the financial supportthe Science and Technology Project of Henan Province(No.202102310328)the PhD Start-up Program of Anyang Institute of Technology(No.BSJ 2021042)Guangzhou Basic and Applied Basic Research Project in China(Nos.202102020134,202102020690)Youth Innovation Talents Project of Guangdong Universities(natural science)in China(No.2019KQNCX098)the Henan Postdoctoral Foundation and the Postdoctoral Innovation Base of Anyang Institute of Technology for financial support。
文摘A cobalt-catalyzed ring-opening/hydroxylation cascade of highly strained cyclopropanols has been developed for the first time. The reaction was conducted under open-air atmosphere to afford a broad series of structurally diverse β-hydroxy ketones in moderate to good yields with high regioselectivity.The protocol features mild reaction conditions, simple operation, high-functional-group tolerance, facile scalability, and heterocycle compatibility.
基金supported by the National Basic Research Program of China(2013CB932800)the National Natural Science Foundation of China(21532004,21225207,81621002)
文摘Histone H2A methylation at Glnl04 （H2AQ104Me） is a new type of histone post-translational modification （PTM） discovered recently. This modification has been found to have significant influence on gene transcription. However, the structural and fimctional consequence of glutamine methylation on nucleosome remains to be further elucidated. Obtaining of histones with site-specific methylation at glutamine residues might facilitate the studies towards a better understanding of this new PTM. In the present work, total chemical synthesis of H2AQ 104Me was carried out through use of the hydrazide-based native chemical ligation. Synthetic histone H2AQ104Me could be successfully incorporated into nucleosomes in vitro and showed a negative influence on the nucleosome stability.
基金supported by the National Natural Science Foundation of China(NSFC)(No.82272743 to Xin Yue(82172812)of NSFC to Ran-yi Liu+4 种基金81871996 to Ran-yi Liu82003218 to Xuecen Wang82072029 to Zhenwei Peng and 81973174 to Xianzhang Bu)Guangdong Basic and Applied Basic Research Foundation(No.2021A1515012496 to Xin Yue and 2022A1515012221 to Xianzhang Bu)Basic Scientific Research Operation of Sun Yat-sen University(No.19ykpy192 to Xin Yue)。
文摘Radiotherapy is widely used in the management of advanced colorectal cancer(CRC).However,the clinical efficacy is limited by the safe irradiated dose.Sensitizing tumor cells to radiotherapy via interrupting DNA repair is a promising approach to conquering the limitation.The BRCA1-BARD1 complex has been demonstrated to play a critical role in homologous recombination(HR)DSB repair,and its functions may be affected by HERC2 or BAP1.Accumulated evidence illustrates that the ubiquitination-deubiquitination balance is involved in these processes;however,the precise mechanism for the cross-talk among these proteins in HR repair following radiation hasn’t been defined.Through activity-based profiling,we identified PT33 as an active entity for HR repair suppression.Subsequently,we revealed that BAP1 serves as a novel molecular target of PT33 via a CRISPR-based deubiquitinase screen.Mechanistically,pharmacological covalent inhibition of BAP1 with PT33 recruits HERC2 to compete with BARD1 for BRCA1 interaction,interrupting HR repair.Consequently,PT33 treatment can substantially enhance the sensitivity of CRC cells to radiotherapy in vitro and in vivo.Overall,these findings provide a mechanistic basis for PT33-induced HR suppression and may guide an effective strategy to improve therapeutic gain.
基金supported by the National Natural Science Foundation of China(22271007)the Peking University Shenzhen Graduate School+2 种基金the State Key Laboratory of Chemical Oncogenomicsthe Guangdong Provincial Key Laboratory of Chemical Genomicsthe Shenzhen Bay Laboratory and Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs for JSZ。
文摘Enantioselective domino alkenylation-alkynylation of olefins is achieved for the first time,using terminal alkynes directly as pronucleophiles.The new reaction enables facile construction of azacycles carrying quaternary stereocenters,including 5–7 membered pyrrolidines,piperidines and tetrahydroazepines.Moreover,alkynyl groups in azacyclic products provide a useful handle for derivatization that formed both fused and bridged azabicycles.
基金partially supported by the National Natural Science Foundation of China (No. 31110103904)the National Program on Key Basic Research Project (973 Program) of the Ministry of Science and Technology of China (Nos. 2011CBA01000 and 2012CB945101)
文摘Targeted genome modifications with the Cas9/gRNA system derived from the clustered regularly interspaced short palin- dromic repeat/CRISPR-associated （CRISPR/Cas） system have been successfully used in cultured human cells as well as in most model organisms, including zebrafish （Danio rerio）, mouse, and fruit fly （Chang et al., 2013; Cong et al., 2013; Gratz et al., 2013; Hwang et al., 2013; Jao et al., 2013; Shen et al., 2013; Wei et al., 2013）. Its application in zebrafish is particu- larly attractive due to the ease of handling this organism and the simple application of this method by direct injection of Cas9/ gRNA. However, the information about its specificity in this organism is very limited and needs further evaluation. In addition, it is conceivable that a Cas9 mRNA optimized for zebrafish codon preference could enhance its activity.
基金This study was supported by grants from the National Natural Science Foundation of China （31030050, 81520108004, and 81470422 to H.-T.Y.）, the Strategic Priority Research Program of Chinese Academy of Sciences （XDA01020204 to H.-T.Y.）, the National Basic Research Program of China （2014CB965100 to H.-T.Y.）, the National Science and Technology Major Project （2012ZX09501001 to H.-T.Y.）, and the Shenzhen Science, Technology and Innovation Committee OCYI 20160428154108239 to K.O.）.
文摘Ca2＋ signals participate in various cellular processes with spatial and temporal dynamics, among which, inositol 1,4,5-trisphosphate receptors （IP3Rs）-mediated Ca2＋ signals are essential for early development. However, the underlying mechanisms of IP3R- regulated cell fate decision remain largely unknown. Here we report that IP3Rs are required for the hematopoietic and cardiac fate divergence of mouse embryonic stem cells （mESCs）. Deletion of IP3Rs （IP3R-tKO） reduced FIkl＋/PDGFRα- hematopoietic mesoderm, c-Kit＋/CD41＋ hematopoietic progenitor ceil population, and the colony-forming unit activity, but increased cardiac progenitor markers as well as cardiomyocytes. Concomitantly, the expression of a key regulator of hematopoiesis, Ely2, was reduced in IP3R-tKO cells, which could be rescued by the activation of Ca2＋ signals and calcineurin or overexpression of constitutively active form of NFATc3. Furthermore, IP3R-tKO impaired specific targeting of Ely2 by NFATc3 via its evolutionarily conserved cis-element in differentiating ESCs. Importantly, the activation of Ca2＋-calcineurin-NFAT pathway reversed the phenotype of IP3R-tKO cells. These findings reveal an unrecognized governing role of IP3Rs in hematopoietic and cardiac fate commitment via IP3Rs-Ca2＋-calcineurin-NFATc3- Etv2 pathway.
基金supported by the National Key R&D Program of China(2017YFA0505200)the National Natural Science Foundation of China(91753205,21532004,21761142008)the Program of Introducing Talents of Discipline to Universities of China(B16028)
文摘Ubiquitin(Ub) chain isopeptide bond mimics are useful molecules for biochemical and biophysical studies. Herein, we report the semi-synthesis of the disulfide-linked K11/K48-branched tri-Ub(Ub_3^(11/48)(S-S)), the first example of an isopeptide mimic for the branched Ub chains,which have recently emerged as an interesting category of Ub modifications. Our strategy comprised the El-dependent synthesis of the Ub conjugate of aminoethanethiol, followed by disulfide formation with Ub(K11 C, K48 C). The structure of the synthetic isopeptide bond mimics was verified by the crystal structure of Ub_3^(11/48)(S-S). Deubiquitination and pulldown assays indicated that the synthetic Ub_3^(11/48)(S-S) could be hydrolyzed by linkage-specific deubiquitinases(K11-specific Cezanne and K48-specific OTUB1), and recognized by proteasomal ubiquitin receptor S5 a.
基金supported by the grants of National Basic Research Program(973 Program,2010CB833201 & 2009CB940904)the National Science and Technology Major Project "Development of Key Technology for the Combinatorial Synthesis of Privileged Scaffolds" (2009ZX09501-012)the National Natural Science Foundation of China(20821062,20832003 and 20902007)
文摘A unified strategy toward the construction of the [5.7.6]tricyclic skeleton of liphagal is reported,featuring InCl3-mediated intramolecular Friedel-Crafts-type cyclization.
基金supported by the National Natural Science Foundation of China(21502086)the Natural Science Foundation of Fujian Province(2019J01744)+1 种基金the Key Project of Foundation of Fujian Province(2020J02044)the Natural Science Foundation of Zhangzhou City(ZZ2021J13)。
文摘Direct functionalization of inert C(sp^(3))–H bonds in pharmaceutically significant compounds is very important in modern synthetic organic chemistry.In this article,we disclose a practical and efficient method for the oxidative lactonization of benzylic C(sp^(3))–H bonds enabled by the synergistic interactions of organic dye-type rose bengal,n-Bu_(4)N∙Br,O_(2) and Na_(2)HPO_(4) under visible light irradiation.This reaction does not require transition metal catalysts or strong oxidants.A range of structurally diverse phthalides has been synthesized with excellent selectivity and high functional group compatibility.The late-stage application of this reaction to the preparation of structurally complex phthalides demonstrates its synthetic utility.
基金the National Key Research and Development Program of China(2016YFA01001002017YFA0103000)+4 种基金the National Natural Science Foundation of China(Grant Nos.31730059 and 31521004)the Guangdong Innovative and En trepreneurial Research Team Program(2014ZT05S216)the Science and Technology Planning Project of Guangdong Province,China(2014B020226001 and 2016B030232001)the Science and Technology Program of Guangzhou,China(201508020001)National Natural Science Foundation of China(Grant No.31571052).
文摘One major strategy to generate genetically modified mouse models is gene targeting in mouse embryonic stem(ES)cells,which is used to produce gene-targeted mice for wide applications in biomedicine.However,a major bottleneck in this approach is that the robustness of germiine transmission of gene-targeted ES cells can be significantly reduced by their genetic and epigenetic instability after long-term culturing,which impairs the efficiency and robustness of mouse model generation.Recently,we have established a new type of pluripotent cells termed extended pluripotent stem(EPS)cells,which have superior developmental potency and robust germline competence compared to conventional mouse ES cells.In this study,we demonstrate that mouse EPS cells well maintain developmental potency and genetic stability after long-term passage.Based on gene targeting in mouse EPS cells,we established a new approach to directly and rapidly generate gene-targeted mouse models through tetraploid complementation,Haibo Li and Chaoran Zhao contributed equally to this work.Electronic supplementary material The online version of this article(https://doi.org/10.1007/s13238-018-0556-1)contains supplementary material,which is available to authorized users.which could be accomplished in approximately 2 months.Importantly,using this approach,we successfully constructed mouse models in which the human interleukin 3(IL3)or interleukin 6(IL6)gene was knocked into its corresponding locus in the mouse genome.Our study demonstrates the feasibility of using mouse EPS cells to rapidly generate mouse models by gene targeting,which have great application potential in biomedical research.
基金Weacknowledge financial support from the National Natural Science Foundation of China(Nos.21772009,21901013)the Shenzhen Peacock Plan(No.KQTD2015071714043444)+1 种基金the Shenzhen Science and Technology Innovation Commission(Nos.JCYJ20170818090017617,JCYJ20170818090238288)the GDNSF(No.2014B030301003).We thank Dr.Long Dang for kindly providing the isogenic HCT116 knockout cells.
文摘of main observation and conclusion We have achieved the total synthesis of an architecturally and biologically intriguing cyclic polypeptide,rhizonin A(1);in an exceptionally concise and convergent fashion.The strategic route entails 9 longest linear steps to elaborate commercially available materials into the natural product with an overall yield of 9.7%.The brevity of sequence and high overall yield was fueled by the judicious selection of chemical tactics.Rhizonin A(1)showed weak inhibitory effects on the cell viability of HCT116 colorectal cancer cells and this activity was dependent on hypoxia-inducible factors.
基金We thank M.Itoh,M.M.Chiu,G.Weinmaster,J.Hald,Z.Li and D.Yao for reagents and other members of our lab for technical support.This work was supported by grants from the“Strategic Priority Research Program”of the Chinese Academy of Sciences(XDA01020401,XDA01020307)Ministry of Science and Technology 973 program(2009CB941102)CAS 100-talent project(X.S.).
文摘Background:Notch is one of the most important signaling pathways involved in cell fate determination.Activation of the Notch pathway requires the binding of a membrane-bound ligand to the Notch receptor in the adjacent cell which induces proteolytic cleavages and the activation of the receptor.A unique feature of the Notch signaling is that processes such as modification,endocytosis or recycling of the ligand have been reported to play critical roles during Notch signaling,however,the underlying molecular mechanism appears context-dependent and often controversial.Results:Here we identified SNX17 as a novel regulator of the Notch pathway.SNX17 is a sorting nexin family protein implicated in vesicular trafficking and we find it is specifically required in the ligand-expressing cells for Notch signaling.Mechanistically,SNX17 regulates the protein level of Jag1a on plasma membrane by binding to Jag1a and facilitating the retromer-dependent recycling of the ligand.In zebrafish,inhibition of this SNX17-mediated Notch signaling pathway results in defects in neurogenesis as well as pancreas development.Conclusions:Our results reveal that SNX17,by acting as a cargo-specific adaptor,promotes the retromer dependent recycling of Jag1a and Notch signaling and this pathway is involved in cell fate determination during zebrafish neurogenesis and pancreas development.
基金supported by the National Natural Science Foundation of China (Nos. 21772008, 21632002 and U1606403)Natural Science Foundation of Guangdong Province (No. 2016A030306011)+1 种基金Shenzhen Basic Research Program (Nos. JCYJ20170818090044432 and JCYJ20160226105337556)Qingdao National Laboratory for Marine Science and Technology (No. LMDBKF201703)
文摘In this paper,we report the concise total syntheses of three botryane sesquiterpenoids:dehydrobotrydienal,dehydrobotrydienol,and 10-oxodehydrodihydrobotrydial.The key transformations include tandem Co-tetramethylthiourea-catalyzed Pauson–Khand and 6π-electrocyclization reactions to forge the tricyclic core structure of the botryanes,and further oxidative aromatization and oxidation to complete the total syntheses.
