The assessment of nanomechanical properties of a single amyloid fibril in a confined space provides important information for understanding the role of fibrils in a cell microenvironment. In this study, the structure ...The assessment of nanomechanical properties of a single amyloid fibril in a confined space provides important information for understanding the role of fibrils in a cell microenvironment. In this study, the structure and nanomechanical properties of different fibrils formed in water nanofilms on mica surface are carefully investigated by using the new atomic force microscopy imaging mode-peak force quantitative nanomechanics (PF-QNM). We find that two types of fibrils with different morphologies are formed in water nanofilm on mica. The compression elasticities of these two types of fibrils are 3.9±0.9 and 2.5±0.6 GPa, respectively. The remarkable difference is possibly due to the structural discrepancy in two types of fibrils.展开更多
The modification of amyloid fibrils cytotoxicity through exogenous nanomaterials is crucial to understand the processes controlling the role of protein aggregation in the related diseases.The influence of nanoparticle...The modification of amyloid fibrils cytotoxicity through exogenous nanomaterials is crucial to understand the processes controlling the role of protein aggregation in the related diseases.The influence of nanoparticles on amyloid stability yields great interest due to the small size and high surface area-to-volume ratio of nanoparticles.Various physico-chemical parameters play a role in the interaction of proteins and nanoparticles in solution,thus influencing the disaggregation of preformed fibrils.We have examined the influence of two kinds of metallic nanoparticles on lysozyme amyloid fibrils using a multi-technique approach and focalized their impact on cytotoxicity on human neuroblastoma cells(SH-SY5Y).In particular,fluorescence,infrared and circular dichroism spectroscopies,optical and atomic force microscopy experiments have been carried out;the results are analyzed to rationalize the effects of these complexes on neural cell viability.It is remarkable,that the fibrils in the presence of AuNPs,unlike fibrils alone or with AgNPs,do not generate a significant cytotoxic effect even at high concentration and an amyloid degradation effect is visible.展开更多
The formation of amyloid plaques usually occurs in the early-stage of Alzheimer’s disease(AD).Stimulated emission depletion(STED)imaging provided a powerful tool for visualizing amyloid structures on the nanometer sc...The formation of amyloid plaques usually occurs in the early-stage of Alzheimer’s disease(AD).Stimulated emission depletion(STED)imaging provided a powerful tool for visualizing amyloid structures on the nanometer scale.However,many commercial probes adopted in detecting amyloid fibrils are inapplicable to STED imaging,owing to their unmatched absorption and emission wavelengths,small Stokes'shift,easy photo-bleaching,etc.Herein,we demonstrated a polarity-activated STED probe based on an intramolecular charge transfer donor(D)-7c-acceptor(A)compound.The electron-rich carbazole group and the electron-poor pyridinium bromide group,linked by 7i-conjugated thiophen-bridge,ensure strong near infrared(NIR)emission with a Stokes'shift larger than 200 nm.The tiny change in polarity before and after binding with amyloid plaques leads to a transition from weakly emission charge-transfer(CT)state(Φ<0.04)to highly emissive locally-excited(LE)state(Φ=0.57),giving rise to a fluorescence Turn-On probe.Together with large Stokes'shift,good photostability and high depletion efficiency,the super-resolution imaging of the formation and morphology of amyloid fibrils in vitro based on this probe was realized with a lateral spatial resolution better than 33 nm at an extremely low depletion power.Moreover,the ex-vivo super-resolution imaging of(E)-1-butyl-4(2-(5-(9-ethyl-9Hcarbazol-3-yl)thiophen-2-yl)vinyl)pyridinium bromide(CTPB)probe in Aβ plaques in the brain slices of a Tg mouse was demonstrated.This research provides a demonstration of the super resolution imaging probe of amyloid fibrils based on polarity-response mechanism,providing a new approach to the development of future amyloid probes.展开更多
Nickel,an important transi-tion metal element,is one of the trace elements for hu-man body and has a crucial impact on life and health.Some evidences show the excess exposure to metal ions might be associated with neu...Nickel,an important transi-tion metal element,is one of the trace elements for hu-man body and has a crucial impact on life and health.Some evidences show the excess exposure to metal ions might be associated with neurological diseases.Herein,we applied Raman spectroscopy to study the Ni(II)ion effect on kinetics of amyloid fibrillation of hen egg white lysozyme(HEWL)in thermal and acidic conditions.Using the well-known Raman indicators for protein tertiary and secondary structures,we monitored and analyzed the concentration effect of Ni(II)ions on the unfolding of tertiary structures and the transformation of sec-ondary structures.The experimental evidence validates the accelerator role of the metal ion in the kinetics.Notably,the additional analysis of the amide I band profile,combined with thioflavin-T fluorescence assays,clearly indicates the inhibitory effect of Ni(II)ions on the formation of amyloid fibrils with organizedβ-sheets structures.Instead,a more significant promotion influence is affirmed on the assembly into other aggregates with disordered struc-tures.The present results provide rich information about the specific metal-mediated protein fibrillation.展开更多
In artificial photosynthesis systems,synthetic diiron complexes are popular[FeFe]-hydrogenase mimics,which are attractive for the fabrication of photocatalyst-protein hybrid structures to amplify hydrogen(H2)generatio...In artificial photosynthesis systems,synthetic diiron complexes are popular[FeFe]-hydrogenase mimics,which are attractive for the fabrication of photocatalyst-protein hybrid structures to amplify hydrogen(H2)generation capability.However,constructing a highly bionic and efficient catalytic hybrid system is a major challenge.Notably,we designed an ideal hybrid nanofibrils system that incorporates the crucial components:(1)a[FeFe]-H2ase mimic,which has a three-arm architecture(named triFeFe)for more interaction sites and higher catalytic activity and(2)uniform hybrid nanofibrils as the biological environment in which cysteine-catalyst coordination and the hydrogen-bonding network play a vital role in both catalyst binding and hydrogen evolution reaction activity.The assembled hybrid nanofibrils achieve efficient H2 generation with a turnover number of 2.3×103,outperforming previously reported diiron catalyst-protein hybrid systems.Additionally,the hybrid nanofibrils work with photosynthetic thylakoids to produce H2,without extra photosensitizers or electron shuttle proteins,which advances the bioengineering of living systems for solar-driven biofuel production.展开更多
The deposition of highly ordered amyloid fibrils is recognized as a hallmark of amyloidosis diseases such as Alzheimer’s disease and Parkinson’s disease.Disaggregating the amyloid fibrils is considered as one of the...The deposition of highly ordered amyloid fibrils is recognized as a hallmark of amyloidosis diseases such as Alzheimer’s disease and Parkinson’s disease.Disaggregating the amyloid fibrils is considered as one of the effective strategies for the control and treatment of amyloidosis diseases.In this article,by simulating the function of natural molecular chaperones,co-assembled block copolymer micelles with coordination groups of nitrilotriacetic acid(NTA)and hydrophobic microdomains of poly(Nisopropylacrylamide)(PNIPAM)on the surface were used as nanochaperones(n Chaps)to disaggregate amyloid insulin fibrils.Zinc ions chelated by NTA can bind the histidine imidazole residues while the PNIPAM microdomains can interact with the exposed hydrophobic sites on the amyloid insulin fibrils,which synergistically perturb the stability of amyloid insulin fibrils,loosen their structure,and finally promote their disaggregation.A combination of characterizations with fluorescence spectroscopy,transmission electron microscopy(TEM),dynamic hight scattering(DLS),and quartz crystal microbalance(QCM)demonstrated that mature amyloid insulin fibrils were completely disaggregated after incubating with n Chaps for 90 h.This study may provide a promising strategy for the development of n Chaps for the treatment of amyloidosis diseases.展开更多
The formation of amyloid fibrils from soluble proteins is a common form of self-assembly phenomenon that has fundamental connections with biological functions and human diseases.Lysozyme was converted from its soluble...The formation of amyloid fibrils from soluble proteins is a common form of self-assembly phenomenon that has fundamental connections with biological functions and human diseases.Lysozyme was converted from its soluble native state into highly organized amyloid fibrils.Ultrasonic treatment was used to break amyloid fibrils to fibrillar fragments–seeds.Atomic force microscopy and fluorescence microscopy was employed to characterize the morphology of the amyloid assemblies and neural cells–amyloid complexes.Our results demonstrate that prefibrillar intermediated and their mixture with proteins exhibit toxicity,although native proteins and fibrils appear to have no effect on number of cells.Our findings confirm that innocuous hen lysozyme can be engineered to produce both cytotoxic fibrillar fragments and non-toxic mature amyloid fibrils.Our work further strengthens the claim that amyloid conformation,and not the identity of the protein,is key to cellular toxicity and the underlying specific cell death mechanism.展开更多
Amyloid fibrils arise from the aggregation of misfolded proteins into highly-ordered structures.The accumulation of these fibrils along with some non-fibrillar constituents within amyloid plaques is associated with th...Amyloid fibrils arise from the aggregation of misfolded proteins into highly-ordered structures.The accumulation of these fibrils along with some non-fibrillar constituents within amyloid plaques is associated with the pathogenesis of several human degenerative diseases.A number of plasma apolipoproteins,including apolipoprotein(apo)A-I,apoA-II,apoC-II and apoE are implicated in amyloid formation or influence amyloid formation by other proteins.We review present knowledge of amyloid formation by apolipoproteins in disease,with particular focus on atherosclerosis.Further insights into the molecular mechanisms underlying their amyloidogenic propensity are obtained from in vitro studies which describe factors affecting apolipoprotein amyloid fibril formation and interactions.Additionally,we outline the evidence that amyloid fibril formation by apolipoproteins might play a role in the development and progression of atherosclerosis,and highlight possible molecular mechanisms that could contribute to the pathogenesis of this disease.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No 11474173the Natural Science Foundation of Zhejiang Province under Grant Nos LY14A040006 and LQ14F040002+1 种基金the Ningbo Natural Science Foundation under Grant Nos2014A610202 and 2014A610149the K.C.Wong Magna Fund in Ningbo University
文摘The assessment of nanomechanical properties of a single amyloid fibril in a confined space provides important information for understanding the role of fibrils in a cell microenvironment. In this study, the structure and nanomechanical properties of different fibrils formed in water nanofilms on mica surface are carefully investigated by using the new atomic force microscopy imaging mode-peak force quantitative nanomechanics (PF-QNM). We find that two types of fibrils with different morphologies are formed in water nanofilm on mica. The compression elasticities of these two types of fibrils are 3.9±0.9 and 2.5±0.6 GPa, respectively. The remarkable difference is possibly due to the structural discrepancy in two types of fibrils.
基金This work was partially supported by Slovak grand agency VEGA 2/0145/17,APW-18-0284,Italian flagship NANOMAX,N-CHEM,Ministery o f Education,University and Research(PRIN grant 20173L7W8K).Microscopy was carried out at the SPM@ISMN facility.
文摘The modification of amyloid fibrils cytotoxicity through exogenous nanomaterials is crucial to understand the processes controlling the role of protein aggregation in the related diseases.The influence of nanoparticles on amyloid stability yields great interest due to the small size and high surface area-to-volume ratio of nanoparticles.Various physico-chemical parameters play a role in the interaction of proteins and nanoparticles in solution,thus influencing the disaggregation of preformed fibrils.We have examined the influence of two kinds of metallic nanoparticles on lysozyme amyloid fibrils using a multi-technique approach and focalized their impact on cytotoxicity on human neuroblastoma cells(SH-SY5Y).In particular,fluorescence,infrared and circular dichroism spectroscopies,optical and atomic force microscopy experiments have been carried out;the results are analyzed to rationalize the effects of these complexes on neural cell viability.It is remarkable,that the fibrils in the presence of AuNPs,unlike fibrils alone or with AgNPs,do not generate a significant cytotoxic effect even at high concentration and an amyloid degradation effect is visible.
基金This work was supported by the Ministry of Science and Technology of China(Nos.2017YFA0204503 and 2018YFA0704805)the National Natural Science Foundation of China(Nos.21503139,21573251,21673144,21873065,21833005,81970425 and 21790364)+5 种基金the Beijing Natural Science Foundation of China(No.2192011)the High-level Teachers in Bejing Municipal Universities in the Period of 13^th Five-year Plan(Nos.IDHT20180517 and CIT&TCD20180331)the Open Fund of the State Key Laboratory of Integrated Optoelectronics(No.IOSKL2019KF01)Capacity Building for Sci-Tech Innovation-Fundamental Scientific Research Funds(Nos.025185305000/210,009/19530050162 and 19530012018)Youth Innovative Research Team of Capital Normal University(No,009/19530050148)Beijing Advanced Innovation Center for Imaging Theory and Technology(No.009/19530011009).
文摘The formation of amyloid plaques usually occurs in the early-stage of Alzheimer’s disease(AD).Stimulated emission depletion(STED)imaging provided a powerful tool for visualizing amyloid structures on the nanometer scale.However,many commercial probes adopted in detecting amyloid fibrils are inapplicable to STED imaging,owing to their unmatched absorption and emission wavelengths,small Stokes'shift,easy photo-bleaching,etc.Herein,we demonstrated a polarity-activated STED probe based on an intramolecular charge transfer donor(D)-7c-acceptor(A)compound.The electron-rich carbazole group and the electron-poor pyridinium bromide group,linked by 7i-conjugated thiophen-bridge,ensure strong near infrared(NIR)emission with a Stokes'shift larger than 200 nm.The tiny change in polarity before and after binding with amyloid plaques leads to a transition from weakly emission charge-transfer(CT)state(Φ<0.04)to highly emissive locally-excited(LE)state(Φ=0.57),giving rise to a fluorescence Turn-On probe.Together with large Stokes'shift,good photostability and high depletion efficiency,the super-resolution imaging of the formation and morphology of amyloid fibrils in vitro based on this probe was realized with a lateral spatial resolution better than 33 nm at an extremely low depletion power.Moreover,the ex-vivo super-resolution imaging of(E)-1-butyl-4(2-(5-(9-ethyl-9Hcarbazol-3-yl)thiophen-2-yl)vinyl)pyridinium bromide(CTPB)probe in Aβ plaques in the brain slices of a Tg mouse was demonstrated.This research provides a demonstration of the super resolution imaging probe of amyloid fibrils based on polarity-response mechanism,providing a new approach to the development of future amyloid probes.
基金supported by the National Natural Science Foundation of China(No.22073088,No.22027801 and No.21873089).
文摘Nickel,an important transi-tion metal element,is one of the trace elements for hu-man body and has a crucial impact on life and health.Some evidences show the excess exposure to metal ions might be associated with neurological diseases.Herein,we applied Raman spectroscopy to study the Ni(II)ion effect on kinetics of amyloid fibrillation of hen egg white lysozyme(HEWL)in thermal and acidic conditions.Using the well-known Raman indicators for protein tertiary and secondary structures,we monitored and analyzed the concentration effect of Ni(II)ions on the unfolding of tertiary structures and the transformation of sec-ondary structures.The experimental evidence validates the accelerator role of the metal ion in the kinetics.Notably,the additional analysis of the amide I band profile,combined with thioflavin-T fluorescence assays,clearly indicates the inhibitory effect of Ni(II)ions on the formation of amyloid fibrils with organizedβ-sheets structures.Instead,a more significant promotion influence is affirmed on the assembly into other aggregates with disordered struc-tures.The present results provide rich information about the specific metal-mediated protein fibrillation.
基金the National Natural Science Foundation of China(grant nos.22077065,22021002,and 22277054)the National Key R&D Program of China(grant no.2018YFE0200700)+1 种基金the China Postdoctoral Science Foundation(grant no.2021M703264)the Beijing National Laboratory for Molecular Sciences for financial support.
文摘In artificial photosynthesis systems,synthetic diiron complexes are popular[FeFe]-hydrogenase mimics,which are attractive for the fabrication of photocatalyst-protein hybrid structures to amplify hydrogen(H2)generation capability.However,constructing a highly bionic and efficient catalytic hybrid system is a major challenge.Notably,we designed an ideal hybrid nanofibrils system that incorporates the crucial components:(1)a[FeFe]-H2ase mimic,which has a three-arm architecture(named triFeFe)for more interaction sites and higher catalytic activity and(2)uniform hybrid nanofibrils as the biological environment in which cysteine-catalyst coordination and the hydrogen-bonding network play a vital role in both catalyst binding and hydrogen evolution reaction activity.The assembled hybrid nanofibrils achieve efficient H2 generation with a turnover number of 2.3×103,outperforming previously reported diiron catalyst-protein hybrid systems.Additionally,the hybrid nanofibrils work with photosynthetic thylakoids to produce H2,without extra photosensitizers or electron shuttle proteins,which advances the bioengineering of living systems for solar-driven biofuel production.
基金supported by the National Natural Science Foundation of China(51773099,51933006)。
文摘The deposition of highly ordered amyloid fibrils is recognized as a hallmark of amyloidosis diseases such as Alzheimer’s disease and Parkinson’s disease.Disaggregating the amyloid fibrils is considered as one of the effective strategies for the control and treatment of amyloidosis diseases.In this article,by simulating the function of natural molecular chaperones,co-assembled block copolymer micelles with coordination groups of nitrilotriacetic acid(NTA)and hydrophobic microdomains of poly(Nisopropylacrylamide)(PNIPAM)on the surface were used as nanochaperones(n Chaps)to disaggregate amyloid insulin fibrils.Zinc ions chelated by NTA can bind the histidine imidazole residues while the PNIPAM microdomains can interact with the exposed hydrophobic sites on the amyloid insulin fibrils,which synergistically perturb the stability of amyloid insulin fibrils,loosen their structure,and finally promote their disaggregation.A combination of characterizations with fluorescence spectroscopy,transmission electron microscopy(TEM),dynamic hight scattering(DLS),and quartz crystal microbalance(QCM)demonstrated that mature amyloid insulin fibrils were completely disaggregated after incubating with n Chaps for 90 h.This study may provide a promising strategy for the development of n Chaps for the treatment of amyloidosis diseases.
基金supported by Slovak grand agency VEGA 2/0145/17,MVTS COST 083/14 action BM1405,SAS-MOST JRP 2015/5 and CNR-SAS bilateral projects CUP B52F15000340005 and CUP B52I12000320005,Italian flagship NANOMAX,N-CHEM。
文摘The formation of amyloid fibrils from soluble proteins is a common form of self-assembly phenomenon that has fundamental connections with biological functions and human diseases.Lysozyme was converted from its soluble native state into highly organized amyloid fibrils.Ultrasonic treatment was used to break amyloid fibrils to fibrillar fragments–seeds.Atomic force microscopy and fluorescence microscopy was employed to characterize the morphology of the amyloid assemblies and neural cells–amyloid complexes.Our results demonstrate that prefibrillar intermediated and their mixture with proteins exhibit toxicity,although native proteins and fibrils appear to have no effect on number of cells.Our findings confirm that innocuous hen lysozyme can be engineered to produce both cytotoxic fibrillar fragments and non-toxic mature amyloid fibrils.Our work further strengthens the claim that amyloid conformation,and not the identity of the protein,is key to cellular toxicity and the underlying specific cell death mechanism.
文摘Amyloid fibrils arise from the aggregation of misfolded proteins into highly-ordered structures.The accumulation of these fibrils along with some non-fibrillar constituents within amyloid plaques is associated with the pathogenesis of several human degenerative diseases.A number of plasma apolipoproteins,including apolipoprotein(apo)A-I,apoA-II,apoC-II and apoE are implicated in amyloid formation or influence amyloid formation by other proteins.We review present knowledge of amyloid formation by apolipoproteins in disease,with particular focus on atherosclerosis.Further insights into the molecular mechanisms underlying their amyloidogenic propensity are obtained from in vitro studies which describe factors affecting apolipoprotein amyloid fibril formation and interactions.Additionally,we outline the evidence that amyloid fibril formation by apolipoproteins might play a role in the development and progression of atherosclerosis,and highlight possible molecular mechanisms that could contribute to the pathogenesis of this disease.