Estrogen receptor alpha(ERα/ESR1)is overexpressed in over half of all breast cancers and is considered a valuable therapeutic target in ERαpositive breast cancer.Here,we designed a membrane-permeant Chaperonemediate...Estrogen receptor alpha(ERα/ESR1)is overexpressed in over half of all breast cancers and is considered a valuable therapeutic target in ERαpositive breast cancer.Here,we designed a membrane-permeant Chaperonemediated Autophagy Targeting Chimeras(CMATAC)peptide to knockdown endogenous ERαprotein through chaperone-mediated autophagy.The peptide contains a cell membrane-penetrating peptide(TAT)that allows the peptide to by-pass the plasma membrane,anαI peptide as a protein-binding peptide(PBD)that binds specifically to ERα,and CMA-targeting peptide(CTM)that targeting chaperone-mediated autophagy.We validated that ERαtargeting peptide was able to target and degrade ERαto reduce the viability of ERαpositive breast cancer cells.Taken together,our studies provided a new method to reduce the level of intracellular ERαprotein via CMATAC,and thus may provide a new strategy for the treatment of ERαpositive breast cancer.展开更多
The rat chimera is an important animal model for the study of complex human diseases. In the present study we evaluated the chimeric potential of rat inner cell masses （ICMs） and fetal neural stem （FNS） cells. In ...The rat chimera is an important animal model for the study of complex human diseases. In the present study we evaluated the chimeric potential of rat inner cell masses （ICMs） and fetal neural stem （FNS） cells. In result, three rat chimeras were produced by day 5 （D5） Sprague-Dawley （SD） blastocysts injected with ICMs derived from day 6 （D6） and D5 Dark Agouti （DA） blastocysts; four rat chimeras had been generated by D5 DA blastocyst injected with D5 SD ICMs. For the requirement of gene modification, cultured rat inner cell mass cells were assessed to produce chimeras, but no chimeras were generated from injected embryos. The potential to generate chimeras from rFNS and transfected rFNS cells were tested, but no chimeric pups were produced. Only 2 of 41 fetuses derived from D5 DA blastocyst injection with SD LacZ transfected rFNS cells showed very low number of LacZ positive cells in the section. These results indicate that DA and SD rat ICMs arc able to contribute to chimeras, but their potential decreases significantly after culture in vitro （P〈0.05）, and rFNS cells only have the potential to contribute to early fetal development.展开更多
In the field of developmental biology and regenerative medicine,mammalian interspecific chimeras have been proved very useful for investigating early embryonic development and the immune system establishment,and exten...In the field of developmental biology and regenerative medicine,mammalian interspecific chimeras have been proved very useful for investigating early embryonic development and the immune system establishment,and extended to a promising potential for human organ generation（Rossant et al.,1982）.展开更多
Interspecies chimera through blastocyst complementation could be an alternative approach to create human organs in animals by using human pluripotent stem cells.A mismatch of the major histocompatibility complex of va...Interspecies chimera through blastocyst complementation could be an alternative approach to create human organs in animals by using human pluripotent stem cells.A mismatch of the major histocompatibility complex of vascular endothelial cells between the human and host animal will cause graft rejection in the transplanted organs.Therefore,to achieve a transplantable organ in animals without rejection,creation of vascular endothelial cells derived from humans within the organ is necessary.In this study,to explore whether donor xeno-pluripotent stem cells can compensate for blood vasculature in host animals,we generated rat-mouse chimeras by injection of rat embryonic stem cells(rESCs)into mouse blastocysts with deficiency of Flk-1 protein,which is associated with endothelial and hematopoietic cell development.We found that rESCs could differentiate into vascular endothelial and hematopoietic cells in the rat-mouse chimeras.The whole yolk sac(YS)of Flk-1^EGFP/ECFP rat-mouse chimera was full of rat blood vasculature.Rat genes related to vascular endothelial cells,arteries,and veins,blood vessels formation process,as well as hematopoietic cells,were highly expressed in the YS.Our results suggested that rat vascular endothelial cells could undergo proliferation,migration,and self-assembly to form blood vasculature and that hematopoietic cells could differentiate into B cells,T cells,and myeloid cells in rat-mouse chimeras,which was able to rescue early embryonic lethality caused by Flk-1 deficiency in mouse.展开更多
A fractional-order difference equation model of a third-order discrete phase-locked loop(FODPLL) is discussed and the dynamical behavior of the model is demonstrated using bifurcation plots and a basin of attraction. ...A fractional-order difference equation model of a third-order discrete phase-locked loop(FODPLL) is discussed and the dynamical behavior of the model is demonstrated using bifurcation plots and a basin of attraction. We show a narrow region of loop gain where the FODPLL exhibits quasi-periodic oscillations, which were not identified in the integer-order model. We propose a simple impulse control algorithm to suppress chaos and discuss the effect of the control step. A network of FODPLL oscillators is constructed and investigated for synchronization behavior. We show the existence of chimera states while transiting from an asynchronous to a synchronous state. The same impulse control method is applied to a lattice array of FODPLL, and the chimera states are then synchronized using the impulse control algorithm. We show that the lower control steps can achieve better control over the higher control steps.展开更多
Four embryonic stem (ES) cell lines, designated CE1, CE2, CE3 and CE4, were isolated from C57BL/6J blastocysts. The ratio of normal diploid composition of these cell lines is above 70%. To examine the differentiation...Four embryonic stem (ES) cell lines, designated CE1, CE2, CE3 and CE4, were isolated from C57BL/6J blastocysts. The ratio of normal diploid composition of these cell lines is above 70%. To examine the differentiation potential of the ES cells, the CE2 cells were injected subcutaneously into syngenic mice, and many kinds of differentiated cells were observed on the sections of the teratoma derived from this ES cell line. On the other hand, to test the chimeric ability of the ES cells, the CE2 cells were microinjected into the blastocysts of ICR mice, and a chimera was obtained among living pups. These results show that CE2 ES cells are pluripotent stem cells, which can differentiate into many kinds of cell types, and can be used as a cell system for further research.展开更多
Aim: To establish techniques for producing somatic and germline chimeric chicken by transferring blastodermal cellsfused with electroporation. Methods: Stage-X blastodermal cells isolated from freshly laid fertile uni...Aim: To establish techniques for producing somatic and germline chimeric chicken by transferring blastodermal cellsfused with electroporation. Methods: Stage-X blastodermal cells isolated from freshly laid fertile unincubated whiteLeghorn and Rhode Island red chicken eggs were fused with electroporation. The treated cell suspension was transferredto the recovery medium (DMEM containing 10% FBS) and was injected into the subgenninal cavity of recipient unin-cubated embryos (stage X). Results: Of 177 recipient embryos injected with the fusing blastodermal cells, 6(3.4 %) survived to hatching. Somatic chimerism was examined in the melanocyte of the feather. The presence offeathers originating from the donor cell was observed in 1 bird (16.7%) out of the 6 hatched birds. After 21 days ofincubation two birds out of five embryos were subjected to polymerase chain reaction (PCR) analysis for W-chromo-some-specific DNA for each tissue. One bird possessed W-chromosome-specific DNA in the stomach, and the other ex-hibited the same DNA in the left and right gonads and other tissues, but not the stomach. Conclusion: Recipientembryo having electrofused blastodennal cells yields somatic and germline chimeric chickens more successfully.(Asian J Androl 2000 Dec; 2: 271-275)展开更多
Human pluripotent stem cell(hPSC)models provide unprecedented opportunities to study human neurological disorders by recapitulating human-specific disease mechanisms.In particular,hPSC-based human–animal brain chimer...Human pluripotent stem cell(hPSC)models provide unprecedented opportunities to study human neurological disorders by recapitulating human-specific disease mechanisms.In particular,hPSC-based human–animal brain chimeras enable the study of human cell pathophysiology in vivo.In chimeric brains,human neural and immune cells can maintain human-specific features,undergo maturation,and functionally integrate into host brains,allowing scientists to study how human cells impact neural circuits and animal behaviors.The emerging human–animal brain chimeras hold promise for modeling human brain cells and their interactions in health and disease,elucidating the disease mechanism from molecular and cellular to circuit and behavioral levels,and testing the efficacy of cell therapy interventions.Here,we discuss recent advances in the generation and applications of using human–animal chimeric brain models for the study of neurological disorders,including disease modeling and cell therapy.展开更多
Targeted protein degradation(TPD)has transformed drug discovery by eliminating disease-causing proteins rather than merely inhibiting their activity.Proteolysis-targeting chimeras(PROTACs)have significantly advanced t...Targeted protein degradation(TPD)has transformed drug discovery by eliminating disease-causing proteins rather than merely inhibiting their activity.Proteolysis-targeting chimeras(PROTACs)have significantly advanced this field by using bifunctional small molecules to recruit E3 ubiquitin ligases to degrade proteins of interest.However,PROTACs,relying on the ubiquitin-proteasome system,predominantly target cytosolic and nuclear proteins,but they struggle to degrade membrane or extracellular proteins.To address this gap,scientists have developed lysosome-targeting chimeras(LYTACs),which consist of an antibody or peptide binding the target protein,linked to a ligand that binds a cellsurface lysosomal trafficking receptor.By bridging a target protein on the cell surface to a lysosome-shuttling receptor,LYTACs are internalized into the cell and delivered to lysosomes,where acidic enzymes degrade various membrane proteins.In essence,LYTACs broaden the druggable proteome,allowing researchers to modulate“undruggable”targets that PROTACs and traditional inhibitors cannot touch.展开更多
The cDNA chimeras between two subtypes of mouse excitatory amino acid transporter family, mouse excitatory amino acid carrier 1 （mEAAC1） and mouse alanine serine cysteine transporter 1 （mASCT1）, were constructed b...The cDNA chimeras between two subtypes of mouse excitatory amino acid transporter family, mouse excitatory amino acid carrier 1 （mEAAC1） and mouse alanine serine cysteine transporter 1 （mASCT1）, were constructed by recombinant PCR. After transcription in vitro, the cRNA was injected and expressed in Xenopus laevis oocytes. <sup>3</sup>H-Glu and <sup>3</sup>H-Ser were used as isotopic tracer to measure the flux of amino acids. The results showed that there might not be the key amino acids responsible for substractive specificity in the NH<sub>2</sub>-terminal and its adjacent regions of these two transporters, which probably supported the formation of the substrata binding sites.展开更多
Chimera states are firstly discovered in nonlocally coupled oscillator systems.Such a nonlocal coupling arises typically as oscillators are coupled via an external environment whose characteristic time scaleτis so sm...Chimera states are firstly discovered in nonlocally coupled oscillator systems.Such a nonlocal coupling arises typically as oscillators are coupled via an external environment whose characteristic time scaleτis so small(i.e.,τ→0)that it could be eliminated adiabatically.Nevertheless,whether the chimera states still exist in the opposite situation(i.e.,τ≫1)is unknown.Here,by coupling large populations of Stuart–Landau oscillators to a diffusive environment,we demonstrate that spiral wave chimeras do exist in this oscillator-environment coupling system even whenτis very large.Various transitions such as from spiral wave chimeras to spiral waves or unstable spiral wave chimeras as functions of the system parameters are explored.A physical picture for explaining the formation of spiral wave chimeras is also provided.The existence of spiral wave chimeras is further confirmed in ensembles of FitzHugh–Nagumo oscillators with the similar oscillator-environment coupling mechanism.Our results provide an affirmative answer to the observation of spiral wave chimeras in populations of oscillators mediated via a slowly changing environment and give important hints to generate chimera patterns in both laboratory and realistic chemical or biological systems.展开更多
Over the past 20 years,great efforts have been invested in developing site-specific approaches to protein modification to dissect protein functions directly and accurately.Here,we report a proximitytriggered group tra...Over the past 20 years,great efforts have been invested in developing site-specific approaches to protein modification to dissect protein functions directly and accurately.Here,we report a proximitytriggered group transfer strategy from a sulfonium warhead to a Cysteine(Cys)residue of the target protein.With a guiding ligand,cargoes could be transferred selectively from a sulfonium center onto the Cys residue in the vicinity of their binding interface.The successful thalidomide transfer of sulfonium 1-X could be applied intracellularly for epidermal growth factor receptor degradation,highlighting the potential of group transfer strategy as a suite of chemical biology studies,including cell imaging,protein profiling,and protein degradation by simply employing different transferrable groups.展开更多
In comparison of amino acid sequences of 4 kringles of both macrophage stimulating protein (MSP) and hepatocyte growth factor (HGF), consensus motif sequence was determined. According to this consensus sequence, a pai...In comparison of amino acid sequences of 4 kringles of both macrophage stimulating protein (MSP) and hepatocyte growth factor (HGF), consensus motif sequence was determined. According to this consensus sequence, a pair of universal primers were designed. In combination with specific upstream or downstream primer of MSP or HGF respectively, serial fragments containing variant number of kringle (from 1 to 4) can be obtained by once PCR. By ligating the C terminal and N terminal fragments with different combination, serial deletants and chimeras of MSP and HGF were constructed. Sequence analysis showed that the degeneracy for universal primers and the sequences of those constructed deletants and chimeras are desired. Biological assay of these deletants revealed that wild type MSP can inhibit the growth of some tumor cell lines and that kringle 1 of MSP is essential for function as that of HGF.展开更多
Chimera states,a symmetry-breaking spatiotemporal pattern in nonlocally coupled identical dynamical units,have been identified in various systems and generalized to coupled nonidentical oscillators.It has been shown t...Chimera states,a symmetry-breaking spatiotemporal pattern in nonlocally coupled identical dynamical units,have been identified in various systems and generalized to coupled nonidentical oscillators.It has been shown that strong heterogeneity in the frequencies of nonidentical oscillators might be harmful to chimera states.In this work,we consider a ring of nonlocally coupled bicomponent phase oscillators in which two types of oscillators are randomly distributed along the ring:some oscillators with natural.frequency w1 and others with w2.In this model,the heterogeneity in frequency is measured by frequency mismatch|w1-w2|between the oscillators in these two subpopulations.We report that the nonlocally coupled bicomponent phase oscillators allow for chimera states no matter how large the frequency mismatch is.The bicomponent oscillators are composed of two chimera states,one supported by oscillators with natural frequency wI and the other by oscillators with natural frequency w2.The two chimera states in two subpopulations are synchronized at weak frequency mismatch,in which the coberent oscillators in thern share similar mean phase velocity,and are desynchronized at large frequency mismatch,in which the coherent oscillators in different subpopulations have distinct mean phase velocities.The synchronization-desynchronization transition between chimera states in these two subpopulations is observed with the increase in the frequency mismatch.The observed phenomena are theoretically analyzed by passing to the continuum limit and using the Ott-Antonsen approach.展开更多
Drug discovery is a crucial part of human healthcare and has dramatically benefited human lifespan and life quality in recent centuries, however, it is usually time-and effort-consuming. Structural biology has been de...Drug discovery is a crucial part of human healthcare and has dramatically benefited human lifespan and life quality in recent centuries, however, it is usually time-and effort-consuming. Structural biology has been demonstrated as a powerful tool to accelerate drug development. Among different techniques, cryo-electron microscopy(cryo-EM) is emerging as the mainstream of structure determination of biomacromolecules in the past decade and has received increasing attention from the pharmaceutical industry. Although cryo-EM still has limitations in resolution, speed and throughput, a growing number of innovative drugs are being developed with the help of cryo-EM. Here, we aim to provide an overview of how cryo-EM techniques are applied to facilitate drug discovery. The development and typical workflow of cryo-EM technique will be briefly introduced, followed by its specific applications in structure-based drug design, fragment-based drug discovery, proteolysis targeting chimeras, antibody drug development and drug repurposing. Besides cryo-EM, drug discovery innovation usually involves other state-of-the-art techniques such as artificial intelligence(AI), which is increasingly active in diverse areas. The combination of cryo-EM and AI provides an opportunity to minimize limitations of cryo-EM such as automation, throughput and interpretation of mediumresolution maps, and tends to be the new direction of future development of cryo-EM. The rapid development of cryo-EM will make it as an indispensable part of modern drug discovery.展开更多
β-Amyloid(Aβ)is a specific pathological hallmark of Alzheimer's disease(AD).Because of its neurotoxicity,AD patients exhibit multiple brain dysfunctions.Disease-modifying therapy(DMT)is the central concept in th...β-Amyloid(Aβ)is a specific pathological hallmark of Alzheimer's disease(AD).Because of its neurotoxicity,AD patients exhibit multiple brain dysfunctions.Disease-modifying therapy(DMT)is the central concept in the development of AD thera-peutics today,and most DMT drugs that are currently in clinical trials are anti-Aβdrugs,such as aducanumab and lecanemab.Therefore,understanding Aβ's neurotoxic mechanism is crucial for Aβ-targeted drug development.Despite its total length of only a few dozen amino acids,Aβis incredibly diverse.In addition to the well-known Aβ_(1-42),N-terminally truncated,glutaminyl cyclase(QC)catalyzed,and pyroglutamate-modified Aβ(pEAβ)is also highly amyloidogenic and far more cytotoxic.The extracel-lular monomeric Aβ_(x-42)(x=1-11)initiates the aggregation to form fibrils and plaques and causes many abnormal cellular responses through cell membrane receptors and receptor-coupled signal pathways.These signal cascades further influence many cel-lular metabolism-related processes,such as gene expression,cell cycle,and cell fate,and ultimately cause severe neural cell damage.However,endogenous cellular anti-Aβdefense processes always accompany the Aβ-induced microenvironment alterations.Aβ-cleaving endopeptidases,Aβ-degrading ubiquitin-proteasome system(UPS),and Aβ-engulfing glial cell immune responses are all essential self-defense mechanisms that we can leverage to develop new drugs.This review discusses some of the most recent advances in understanding Aβ-centric AD mechanisms and suggests prospects for promising anti-Aβstrategies.展开更多
基金the National Natural Science Foundation of China(Grant Nos:81272260&81572712 to L.Chen)Natural Science Fund for Distinguished Young Scholars of Jiangsu Province(SBK2020010058)the Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘Estrogen receptor alpha(ERα/ESR1)is overexpressed in over half of all breast cancers and is considered a valuable therapeutic target in ERαpositive breast cancer.Here,we designed a membrane-permeant Chaperonemediated Autophagy Targeting Chimeras(CMATAC)peptide to knockdown endogenous ERαprotein through chaperone-mediated autophagy.The peptide contains a cell membrane-penetrating peptide(TAT)that allows the peptide to by-pass the plasma membrane,anαI peptide as a protein-binding peptide(PBD)that binds specifically to ERα,and CMA-targeting peptide(CTM)that targeting chaperone-mediated autophagy.We validated that ERαtargeting peptide was able to target and degrade ERαto reduce the viability of ERαpositive breast cancer cells.Taken together,our studies provided a new method to reduce the level of intracellular ERαprotein via CMATAC,and thus may provide a new strategy for the treatment of ERαpositive breast cancer.
文摘The rat chimera is an important animal model for the study of complex human diseases. In the present study we evaluated the chimeric potential of rat inner cell masses （ICMs） and fetal neural stem （FNS） cells. In result, three rat chimeras were produced by day 5 （D5） Sprague-Dawley （SD） blastocysts injected with ICMs derived from day 6 （D6） and D5 Dark Agouti （DA） blastocysts; four rat chimeras had been generated by D5 DA blastocyst injected with D5 SD ICMs. For the requirement of gene modification, cultured rat inner cell mass cells were assessed to produce chimeras, but no chimeras were generated from injected embryos. The potential to generate chimeras from rFNS and transfected rFNS cells were tested, but no chimeric pups were produced. Only 2 of 41 fetuses derived from D5 DA blastocyst injection with SD LacZ transfected rFNS cells showed very low number of LacZ positive cells in the section. These results indicate that DA and SD rat ICMs arc able to contribute to chimeras, but their potential decreases significantly after culture in vitro （P〈0.05）, and rFNS cells only have the potential to contribute to early fetal development.
基金supported by the grants from the National Natural Science Foundation of China (Nos.31621004,31501188 and 31422038)the Key Research Projects of the Frontier Science of the Chinese Academy of Sciences (QYZDY-SSW-SMC002)the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA16000000)
文摘In the field of developmental biology and regenerative medicine,mammalian interspecific chimeras have been proved very useful for investigating early embryonic development and the immune system establishment,and extended to a promising potential for human organ generation（Rossant et al.,1982）.
基金financially supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA16030503)National Key Research and Development Program of China(2017YFA0105103)+5 种基金Key Research&Development Program of Guangzhou Regenerative Medicine and Health Guangdong Laboratory(2018GZR110104004)Science and Technology Planning Project of Guangdong Province,China(2014A030312001,2017B020231001,2017A050501059,2017B030314056)Science and Technology Program of Guangzhou,China(201704030034)Research Unit of Generation of Large Animal Disease Models,Chinese Academy of Medical Sciences(2019-I2M-5-025)the Science and Technology Planning Project of Jiangmen(2017TD02)the Young People Fund of Wuyi University(2019TD05)。
文摘Interspecies chimera through blastocyst complementation could be an alternative approach to create human organs in animals by using human pluripotent stem cells.A mismatch of the major histocompatibility complex of vascular endothelial cells between the human and host animal will cause graft rejection in the transplanted organs.Therefore,to achieve a transplantable organ in animals without rejection,creation of vascular endothelial cells derived from humans within the organ is necessary.In this study,to explore whether donor xeno-pluripotent stem cells can compensate for blood vasculature in host animals,we generated rat-mouse chimeras by injection of rat embryonic stem cells(rESCs)into mouse blastocysts with deficiency of Flk-1 protein,which is associated with endothelial and hematopoietic cell development.We found that rESCs could differentiate into vascular endothelial and hematopoietic cells in the rat-mouse chimeras.The whole yolk sac(YS)of Flk-1^EGFP/ECFP rat-mouse chimera was full of rat blood vasculature.Rat genes related to vascular endothelial cells,arteries,and veins,blood vessels formation process,as well as hematopoietic cells,were highly expressed in the YS.Our results suggested that rat vascular endothelial cells could undergo proliferation,migration,and self-assembly to form blood vasculature and that hematopoietic cells could differentiate into B cells,T cells,and myeloid cells in rat-mouse chimeras,which was able to rescue early embryonic lethality caused by Flk-1 deficiency in mouse.
基金Project supported by the Center for Nonlinear Systems,Chennai Institute of Technology,India (Grant No. CIT/CNS/2020/RD/061)。
文摘A fractional-order difference equation model of a third-order discrete phase-locked loop(FODPLL) is discussed and the dynamical behavior of the model is demonstrated using bifurcation plots and a basin of attraction. We show a narrow region of loop gain where the FODPLL exhibits quasi-periodic oscillations, which were not identified in the integer-order model. We propose a simple impulse control algorithm to suppress chaos and discuss the effect of the control step. A network of FODPLL oscillators is constructed and investigated for synchronization behavior. We show the existence of chimera states while transiting from an asynchronous to a synchronous state. The same impulse control method is applied to a lattice array of FODPLL, and the chimera states are then synchronized using the impulse control algorithm. We show that the lower control steps can achieve better control over the higher control steps.
文摘Four embryonic stem (ES) cell lines, designated CE1, CE2, CE3 and CE4, were isolated from C57BL/6J blastocysts. The ratio of normal diploid composition of these cell lines is above 70%. To examine the differentiation potential of the ES cells, the CE2 cells were injected subcutaneously into syngenic mice, and many kinds of differentiated cells were observed on the sections of the teratoma derived from this ES cell line. On the other hand, to test the chimeric ability of the ES cells, the CE2 cells were microinjected into the blastocysts of ICR mice, and a chimera was obtained among living pups. These results show that CE2 ES cells are pluripotent stem cells, which can differentiate into many kinds of cell types, and can be used as a cell system for further research.
文摘Aim: To establish techniques for producing somatic and germline chimeric chicken by transferring blastodermal cellsfused with electroporation. Methods: Stage-X blastodermal cells isolated from freshly laid fertile unincubated whiteLeghorn and Rhode Island red chicken eggs were fused with electroporation. The treated cell suspension was transferredto the recovery medium (DMEM containing 10% FBS) and was injected into the subgenninal cavity of recipient unin-cubated embryos (stage X). Results: Of 177 recipient embryos injected with the fusing blastodermal cells, 6(3.4 %) survived to hatching. Somatic chimerism was examined in the melanocyte of the feather. The presence offeathers originating from the donor cell was observed in 1 bird (16.7%) out of the 6 hatched birds. After 21 days ofincubation two birds out of five embryos were subjected to polymerase chain reaction (PCR) analysis for W-chromo-some-specific DNA for each tissue. One bird possessed W-chromosome-specific DNA in the stomach, and the other ex-hibited the same DNA in the left and right gonads and other tissues, but not the stomach. Conclusion: Recipientembryo having electrofused blastodennal cells yields somatic and germline chimeric chickens more successfully.(Asian J Androl 2000 Dec; 2: 271-275)
文摘Human pluripotent stem cell(hPSC)models provide unprecedented opportunities to study human neurological disorders by recapitulating human-specific disease mechanisms.In particular,hPSC-based human–animal brain chimeras enable the study of human cell pathophysiology in vivo.In chimeric brains,human neural and immune cells can maintain human-specific features,undergo maturation,and functionally integrate into host brains,allowing scientists to study how human cells impact neural circuits and animal behaviors.The emerging human–animal brain chimeras hold promise for modeling human brain cells and their interactions in health and disease,elucidating the disease mechanism from molecular and cellular to circuit and behavioral levels,and testing the efficacy of cell therapy interventions.Here,we discuss recent advances in the generation and applications of using human–animal chimeric brain models for the study of neurological disorders,including disease modeling and cell therapy.
文摘Targeted protein degradation(TPD)has transformed drug discovery by eliminating disease-causing proteins rather than merely inhibiting their activity.Proteolysis-targeting chimeras(PROTACs)have significantly advanced this field by using bifunctional small molecules to recruit E3 ubiquitin ligases to degrade proteins of interest.However,PROTACs,relying on the ubiquitin-proteasome system,predominantly target cytosolic and nuclear proteins,but they struggle to degrade membrane or extracellular proteins.To address this gap,scientists have developed lysosome-targeting chimeras(LYTACs),which consist of an antibody or peptide binding the target protein,linked to a ligand that binds a cellsurface lysosomal trafficking receptor.By bridging a target protein on the cell surface to a lysosome-shuttling receptor,LYTACs are internalized into the cell and delivered to lysosomes,where acidic enzymes degrade various membrane proteins.In essence,LYTACs broaden the druggable proteome,allowing researchers to modulate“undruggable”targets that PROTACs and traditional inhibitors cannot touch.
文摘The cDNA chimeras between two subtypes of mouse excitatory amino acid transporter family, mouse excitatory amino acid carrier 1 （mEAAC1） and mouse alanine serine cysteine transporter 1 （mASCT1）, were constructed by recombinant PCR. After transcription in vitro, the cRNA was injected and expressed in Xenopus laevis oocytes. <sup>3</sup>H-Glu and <sup>3</sup>H-Ser were used as isotopic tracer to measure the flux of amino acids. The results showed that there might not be the key amino acids responsible for substractive specificity in the NH<sub>2</sub>-terminal and its adjacent regions of these two transporters, which probably supported the formation of the substrata binding sites.
基金the National Natural Science Foundation of China under Grant No.11875120the Natural Science Foundation of Zhejiang Province under Grant No.LY16A050003.
文摘Chimera states are firstly discovered in nonlocally coupled oscillator systems.Such a nonlocal coupling arises typically as oscillators are coupled via an external environment whose characteristic time scaleτis so small(i.e.,τ→0)that it could be eliminated adiabatically.Nevertheless,whether the chimera states still exist in the opposite situation(i.e.,τ≫1)is unknown.Here,by coupling large populations of Stuart–Landau oscillators to a diffusive environment,we demonstrate that spiral wave chimeras do exist in this oscillator-environment coupling system even whenτis very large.Various transitions such as from spiral wave chimeras to spiral waves or unstable spiral wave chimeras as functions of the system parameters are explored.A physical picture for explaining the formation of spiral wave chimeras is also provided.The existence of spiral wave chimeras is further confirmed in ensembles of FitzHugh–Nagumo oscillators with the similar oscillator-environment coupling mechanism.Our results provide an affirmative answer to the observation of spiral wave chimeras in populations of oscillators mediated via a slowly changing environment and give important hints to generate chimera patterns in both laboratory and realistic chemical or biological systems.
基金Weare grateful for the financial support from the Natural Science Foundation of China(grant nos.21778009,21977010,and 22007033)National Key Research and Development Program“Synthetic Biology”Key Special Project of China(grant no.2018YFA0902504)+3 种基金China Postdoctoral Science Foundation(grant no.2021M690220)the Natural Science Foundation of Guangdong Province(grant nos.2020A1515010522,2020A1515010766,2019A1515110487,and 2019A151-5111184)the Foundation for Basic and Applied Research of Guangdong Province(grant no.2019A1515110489)and the Shenzhen Science and Technology Innovation Committee(grant nos.JCYJ20180507181527112,JCYJ-201805081522131455,and JCYJ20170817172023838).
文摘Over the past 20 years,great efforts have been invested in developing site-specific approaches to protein modification to dissect protein functions directly and accurately.Here,we report a proximitytriggered group transfer strategy from a sulfonium warhead to a Cysteine(Cys)residue of the target protein.With a guiding ligand,cargoes could be transferred selectively from a sulfonium center onto the Cys residue in the vicinity of their binding interface.The successful thalidomide transfer of sulfonium 1-X could be applied intracellularly for epidermal growth factor receptor degradation,highlighting the potential of group transfer strategy as a suite of chemical biology studies,including cell imaging,protein profiling,and protein degradation by simply employing different transferrable groups.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 39730310 and 39700072)
文摘In comparison of amino acid sequences of 4 kringles of both macrophage stimulating protein (MSP) and hepatocyte growth factor (HGF), consensus motif sequence was determined. According to this consensus sequence, a pair of universal primers were designed. In combination with specific upstream or downstream primer of MSP or HGF respectively, serial fragments containing variant number of kringle (from 1 to 4) can be obtained by once PCR. By ligating the C terminal and N terminal fragments with different combination, serial deletants and chimeras of MSP and HGF were constructed. Sequence analysis showed that the degeneracy for universal primers and the sequences of those constructed deletants and chimeras are desired. Biological assay of these deletants revealed that wild type MSP can inhibit the growth of some tumor cell lines and that kringle 1 of MSP is essential for function as that of HGF.
基金This work was supported by the National Natural Science Foundation of China(Grants Nos.11575036 and 11805021).
文摘Chimera states,a symmetry-breaking spatiotemporal pattern in nonlocally coupled identical dynamical units,have been identified in various systems and generalized to coupled nonidentical oscillators.It has been shown that strong heterogeneity in the frequencies of nonidentical oscillators might be harmful to chimera states.In this work,we consider a ring of nonlocally coupled bicomponent phase oscillators in which two types of oscillators are randomly distributed along the ring:some oscillators with natural.frequency w1 and others with w2.In this model,the heterogeneity in frequency is measured by frequency mismatch|w1-w2|between the oscillators in these two subpopulations.We report that the nonlocally coupled bicomponent phase oscillators allow for chimera states no matter how large the frequency mismatch is.The bicomponent oscillators are composed of two chimera states,one supported by oscillators with natural frequency wI and the other by oscillators with natural frequency w2.The two chimera states in two subpopulations are synchronized at weak frequency mismatch,in which the coberent oscillators in thern share similar mean phase velocity,and are desynchronized at large frequency mismatch,in which the coherent oscillators in different subpopulations have distinct mean phase velocities.The synchronization-desynchronization transition between chimera states in these two subpopulations is observed with the increase in the frequency mismatch.The observed phenomena are theoretically analyzed by passing to the continuum limit and using the Ott-Antonsen approach.
基金funded by the National Natural Science Foundation of China (NSFC, 31900046, 81972085, 82172465 and 32161133022)the Guangdong Provincial Key Laboratory of Advanced Biomaterials (2022B1212010003)+7 种基金the National Science and Technology Innovation 2030 Major Program (2022ZD0211900)the Shenzhen Key Laboratory of Computer Aided Drug Discovery (ZDSYS20201230165400001)the Chinese Academy of Science President’s International Fellowship Initiative (PIFI)(2020FSB0003)the Guangdong Retired Expert (granted by Guangdong Province)the Shenzhen Pengcheng ScientistNSFC-SNSF Funding (32161133022)Alpha Mol&SIAT Joint LaboratoryShenzhen Government Top-talent Working Funding and Guangdong Province Academician Work Funding。
文摘Drug discovery is a crucial part of human healthcare and has dramatically benefited human lifespan and life quality in recent centuries, however, it is usually time-and effort-consuming. Structural biology has been demonstrated as a powerful tool to accelerate drug development. Among different techniques, cryo-electron microscopy(cryo-EM) is emerging as the mainstream of structure determination of biomacromolecules in the past decade and has received increasing attention from the pharmaceutical industry. Although cryo-EM still has limitations in resolution, speed and throughput, a growing number of innovative drugs are being developed with the help of cryo-EM. Here, we aim to provide an overview of how cryo-EM techniques are applied to facilitate drug discovery. The development and typical workflow of cryo-EM technique will be briefly introduced, followed by its specific applications in structure-based drug design, fragment-based drug discovery, proteolysis targeting chimeras, antibody drug development and drug repurposing. Besides cryo-EM, drug discovery innovation usually involves other state-of-the-art techniques such as artificial intelligence(AI), which is increasingly active in diverse areas. The combination of cryo-EM and AI provides an opportunity to minimize limitations of cryo-EM such as automation, throughput and interpretation of mediumresolution maps, and tends to be the new direction of future development of cryo-EM. The rapid development of cryo-EM will make it as an indispensable part of modern drug discovery.
基金National Institute of Neurological Disorders and Stroke,Grant/Award Number:2RF1NS095799National Natural Science Foundation of China,Grant/Award Number:31970044 and 91854115Beijing University of Technology Faculty of Environment and Life Seed Funding,Grant/Award Number:049000513202。
文摘β-Amyloid(Aβ)is a specific pathological hallmark of Alzheimer's disease(AD).Because of its neurotoxicity,AD patients exhibit multiple brain dysfunctions.Disease-modifying therapy(DMT)is the central concept in the development of AD thera-peutics today,and most DMT drugs that are currently in clinical trials are anti-Aβdrugs,such as aducanumab and lecanemab.Therefore,understanding Aβ's neurotoxic mechanism is crucial for Aβ-targeted drug development.Despite its total length of only a few dozen amino acids,Aβis incredibly diverse.In addition to the well-known Aβ_(1-42),N-terminally truncated,glutaminyl cyclase(QC)catalyzed,and pyroglutamate-modified Aβ(pEAβ)is also highly amyloidogenic and far more cytotoxic.The extracel-lular monomeric Aβ_(x-42)(x=1-11)initiates the aggregation to form fibrils and plaques and causes many abnormal cellular responses through cell membrane receptors and receptor-coupled signal pathways.These signal cascades further influence many cel-lular metabolism-related processes,such as gene expression,cell cycle,and cell fate,and ultimately cause severe neural cell damage.However,endogenous cellular anti-Aβdefense processes always accompany the Aβ-induced microenvironment alterations.Aβ-cleaving endopeptidases,Aβ-degrading ubiquitin-proteasome system(UPS),and Aβ-engulfing glial cell immune responses are all essential self-defense mechanisms that we can leverage to develop new drugs.This review discusses some of the most recent advances in understanding Aβ-centric AD mechanisms and suggests prospects for promising anti-Aβstrategies.
