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Qin W, Chen D, Wang Y, Liu Z, Zhou B, Bu X, Wen G. Targeting the hydrophobic region of pyroglutamate-modified amyloid-β by tyrocidine A prevents its nucleation-aggregation process and its "catalytic effect" on the Aβs aggregation. J Biochem Mol Toxicol 2024; 38:e23800. [PMID: 39132781 DOI: 10.1002/jbt.23800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Revised: 07/25/2024] [Accepted: 07/30/2024] [Indexed: 08/13/2024]
Abstract
Pyroglutamate (pE)-modified amyloid-β (Aβ) peptides play a crucial role in the development of Alzheimer's disease. pEAβ3-42 can rapidly form oligomers that gradually elongate hydrophobic segments to form β-sheet-rich amyloid intermediates, ultimately resulting in the formation of mature amyloid fibrils. pEAβ3-42 can also catalyze the aggregation of Aβ species and subsequently accelerate the formation of amyloid senile plaques. Considering the recent clinical success of the pEAβ3-42-targeting antibody donanemab, molecules that strongly bind pEAβ3-42 and prevent its aggregation and catalytic effect on Aβs may also provide potential therapeutic options for Alzheimer's disease. Here, we demonstrate that the natural antibiotic cyclopeptide tyrocidine A (TA) not only strongly inhibits the aggregation of Aβ1-42 as previously reported, but also interacts with the hydrophobic C-terminus and middle domain of pEAβ3-42 to maintain an unordered conformation, effectively impeding the formation of initial oligomers and subsequently halting the aggregation of pEAβ3-42. Furthermore, TA can disrupt the "catalytic effect" of pEAβ3-42 on amyloid aggregates, effectively suppressing Aβ aggregation and ultimately preventing the pathological events induced by Aβs.
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Affiliation(s)
- Wenjing Qin
- Department of Clinical Research, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou Medical University, Guangzhou, China
- Medical Innovation Center, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Daoyuan Chen
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China
- Faculty of bioengineering, Zhuhai Campus of Zunyi Medical University, Zhuhai, China
| | - Youqiao Wang
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China
| | - Ziyi Liu
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China
| | - Binhua Zhou
- School of Chinese Ethnic Medicine, Guizhou Minzu University, Guiyang, China
| | - Xianzhang Bu
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China
| | - Gesi Wen
- Department of Clinical Research, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou Medical University, Guangzhou, China
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China
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2
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An J, Kim K, Lim HJ, Kim HY, Shin J, Park I, Cho I, Kim HY, Kim S, McLean C, Choi KY, Kim Y, Lee KH, Kim JS. Early onset diagnosis in Alzheimer's disease patients via amyloid-β oligomers-sensing probe in cerebrospinal fluid. Nat Commun 2024; 15:1004. [PMID: 38307843 PMCID: PMC10837422 DOI: 10.1038/s41467-024-44818-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 01/05/2024] [Indexed: 02/04/2024] Open
Abstract
Amyloid-β (Aβ) oligomers are implicated in the onset of Alzheimer's disease (AD). Herein, quinoline-derived half-curcumin-dioxaborine (Q-OB) fluorescent probe was designed for detecting Aβ oligomers by finely tailoring the hydrophobicity of the biannulate donor motifs in donor-π-acceptor structure. Q-OB shows a great sensing potency in dynamically monitoring oligomerization of Aβ during amyloid fibrillogenesis in vitro. In addition, we applied this strategy to fluorometrically analyze Aβ self-assembly kinetics in the cerebrospinal fluids (CSF) of AD patients. The fluorescence intensity of Q-OB in AD patients' CSF revealed a marked change of log (I/I0) value of 0.34 ± 0.13 (cognitive normal), 0.15 ± 0.12 (mild cognitive impairment), and 0.14 ± 0.10 (AD dementia), guiding to distinguish a state of AD continuum for early diagnosis of AD. These studies demonstrate the potential of our approach can expand the currently available preclinical diagnostic platform for the early stages of AD, aiding in the disruption of pathological progression and the development of appropriate treatment strategies.
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Affiliation(s)
- Jusung An
- Department of Chemistry, Korea University, Seoul, 02841, Korea
| | - Kyeonghwan Kim
- Department of Pharmacy, College of Pharmacy, Yonsei University, Incheon, 21983, Korea
- Yonsei Institute of Pharmaceutical Sciences, College of Pharmacy, Yonsei University, Incheon, 21983, Korea
| | - Ho Jae Lim
- Department of Biomedical Science, Chosun University, Gwangju, 61452, Korea
| | - Hye Yun Kim
- Department of Pharmacy, College of Pharmacy, Yonsei University, Incheon, 21983, Korea
- Yonsei Institute of Pharmaceutical Sciences, College of Pharmacy, Yonsei University, Incheon, 21983, Korea
| | - Jinwoo Shin
- Department of Chemistry, Korea University, Seoul, 02841, Korea
| | - InWook Park
- Department of Pharmacy, College of Pharmacy, Yonsei University, Incheon, 21983, Korea
- Yonsei Institute of Pharmaceutical Sciences, College of Pharmacy, Yonsei University, Incheon, 21983, Korea
| | - Illhwan Cho
- Department of Pharmacy, College of Pharmacy, Yonsei University, Incheon, 21983, Korea
- Yonsei Institute of Pharmaceutical Sciences, College of Pharmacy, Yonsei University, Incheon, 21983, Korea
| | - Hyeong Yun Kim
- Department of Pharmacy, College of Pharmacy, Yonsei University, Incheon, 21983, Korea
| | - Sunghoon Kim
- Department of Pharmacy, College of Pharmacy, Yonsei University, Incheon, 21983, Korea
- Medicinal Bioconvergence Research Center, Institute for Artificial Intelligence and Biomedical Research, Gangnam Severance Hospital, Yonsei University, Incheon, 21983, Korea
- College of Pharmacy, College of Medicine, Interdisciplinary Biomedical Center, Gangnam Severance Hospital, Yonsei University, Incheon, 21983, Korea
| | - Catriona McLean
- Department of Pathology, The Alfred Hospital, Melbourne, 3004, Australia
| | - Kyu Yeong Choi
- Gwangju Alzheimer's & Related Dementia Cohort Research Center, Chosun University, Gwangju, 61452, Korea
| | - YoungSoo Kim
- Department of Pharmacy, College of Pharmacy, Yonsei University, Incheon, 21983, Korea.
- Yonsei Institute of Pharmaceutical Sciences, College of Pharmacy, Yonsei University, Incheon, 21983, Korea.
| | - Kun Ho Lee
- Department of Biomedical Science, Chosun University, Gwangju, 61452, Korea.
- Gwangju Alzheimer's & Related Dementia Cohort Research Center, Chosun University, Gwangju, 61452, Korea.
- Department of Neural Development and Disease, Korea Brain Research Institute, Daegu, 41062, Korea.
| | - Jong Seung Kim
- Department of Chemistry, Korea University, Seoul, 02841, Korea.
- TheranoChem Incorporation, Seongbuk-gu, Seoul, 02856, Korea.
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3
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Gebril HM, Aryasomayajula A, de Lima MRN, Uhrich KE, Moghe PV. Nanotechnology for microglial targeting and inhibition of neuroinflammation underlying Alzheimer's pathology. Transl Neurodegener 2024; 13:2. [PMID: 38173014 PMCID: PMC10765804 DOI: 10.1186/s40035-023-00393-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2023] [Accepted: 12/12/2023] [Indexed: 01/05/2024] Open
Abstract
BACKGROUND Alzheimer's disease (AD) is considered to have a multifactorial etiology. The hallmark of AD is progressive neurodegeneration, which is characterized by the deepening loss of memory and a high mortality rate in the elderly. The neurodegeneration in AD is believed to be exacerbated following the intercoupled cascades of extracellular amyloid beta (Aβ) plaques, uncontrolled microglial activation, and neuroinflammation. Current therapies for AD are mostly designed to target the symptoms, with limited ability to address the mechanistic triggers for the disease. In this study, we report a novel nanotechnology based on microglial scavenger receptor (SR)-targeting amphiphilic nanoparticles (NPs) for the convergent alleviation of fibril Aβ (fAβ) burden, microglial modulation, and neuroprotection. METHODS We designed a nanotechnology approach to regulate the SR-mediated intracellular fAβ trafficking within microglia. We synthesized SR-targeting sugar-based amphiphilic macromolecules (AM) and used them as a bioactive shell to fabricate serum-stable AM-NPs via flash nanoprecipitation. Using electron microscopy, in vitro approaches, ELISA, and confocal microscopy, we investigated the effect of AM-NPs on Aβ fibrilization, fAβ-mediated microglial inflammation, and neurotoxicity in BV2 microglia and SH-SY5Y neuroblastoma cell lines. RESULTS AM-NPs interrupted Aβ fibrilization, attenuated fAβ microglial internalization via targeting the fAβ-specific SRs, arrested the fAβ-mediated microglial activation and pro-inflammatory response, and accelerated lysosomal degradation of intracellular fAβ. Moreover, AM-NPs counteracted the microglial-mediated neurotoxicity after exposure to fAβ. CONCLUSIONS The AM-NP nanotechnology presents a multifactorial strategy to target pathological Aβ aggregation and arrest the fAβ-mediated pathological progression in microglia and neurons.
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Affiliation(s)
- Hoda M Gebril
- Department of Biomedical Engineering, Rutgers University, 599 Taylor Rd., Piscataway, NJ, 08854, USA.
| | - Aravind Aryasomayajula
- Department of Biomedical Engineering, Rutgers University, 599 Taylor Rd., Piscataway, NJ, 08854, USA
| | | | - Kathryn E Uhrich
- Department of Chemistry, University of California, 501 Big Springs Rd., Riverside, CA, 92507, USA
| | - Prabhas V Moghe
- Department of Biomedical Engineering, Rutgers University, 599 Taylor Rd., Piscataway, NJ, 08854, USA.
- Department of Chemical and Biochemical Engineering, Rutgers University, 98 Brett Rd., Piscataway, NJ, 08854, USA.
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Chakravorty A, McCalpin SD, Sahoo BR, Ramamoorthy A, Brooks CL. Free Gangliosides Can Alter Amyloid-β Aggregation. J Phys Chem Lett 2022; 13:9303-9308. [PMID: 36174129 PMCID: PMC9700483 DOI: 10.1021/acs.jpclett.2c02362] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
A recently proposed lipid-chaperone hypothesis suggests that free lipid molecules, not bound to membranes, affect the aggregation of amyloidogenic peptides such as amyloid-β (Aβ) peptides, whose aggregates are the hallmarks of Alzheimer's disease. Here, we combine experiments with all-atom molecular dynamics simulations in explicit solvent to explore the effects of neuronal ganglioside GM1, abundant in mammalian brains, on the aggregation of two principal isoforms of Aβ, Aβ40 and Aβ42. Our simulations show that free GM1 forms stable, highly water-soluble complexes with both isoforms, and nuclear magnetic resonance experiments support the formation of well-ordered, structurally compact GM1+Aβ complexes. By simulation, we also show that Aβ40 monomers display a preference for binding to GM1-containing hetero-oligomers over GM1-lacking homo-oligomers, while Aβ42 monomers have the opposite preference. These observations explain why GM1 dose-dependently inhibits Aβ40 aggregation but has no effect on Aβ42 aggregation, as assessed by thioflavin T fluorescence.
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Affiliation(s)
- Arghya Chakravorty
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, United States
| | - Samuel D. McCalpin
- Department of Chemistry, Biophysics Program, Biomedical Engineering, Macromolecular Engineering and Science, Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI 48109, United States
| | - Bikash R. Sahoo
- Department of Chemistry, Biophysics Program, Biomedical Engineering, Macromolecular Engineering and Science, Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI 48109, United States
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, United States
| | - Ayyalusamy Ramamoorthy
- Department of Chemistry, Biophysics Program, Biomedical Engineering, Macromolecular Engineering and Science, Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI 48109, United States
| | - Charles L. Brooks
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, United States
- Department of Chemistry, Biophysics Program, Biomedical Engineering, Macromolecular Engineering and Science, Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI 48109, United States
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Siposova K, Petrenko VI, Garcarova I, Sedlakova D, Almásy L, Kyzyma OA, Kriechbaum M, Musatov A. The intriguing dose-dependent effect of selected amphiphilic compounds on insulin amyloid aggregation: Focus on a cholesterol-based detergent, Chobimalt. Front Mol Biosci 2022; 9:955282. [PMID: 36060240 PMCID: PMC9437268 DOI: 10.3389/fmolb.2022.955282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Accepted: 07/22/2022] [Indexed: 11/15/2022] Open
Abstract
The amyloidogenic self-assembly of many peptides and proteins largely depends on external conditions. Among amyloid-prone proteins, insulin attracts attention because of its physiological and therapeutic importance. In the present work, the amyloid aggregation of insulin is studied in the presence of cholesterol-based detergent, Chobimalt. The strategy to elucidate the Chobimalt-induced effect on insulin fibrillogenesis is based on performing the concentration- and time-dependent analysis using a combination of different experimental techniques, such as ThT fluorescence assay, CD, AFM, SANS, and SAXS. While at the lowest Chobimalt concentration (0.1 µM; insulin to Chobimalt molar ratio of 1:0.004) the formation of insulin fibrils was not affected, the gradual increase of Chobimalt concentration (up to 100 µM; molar ratio of 1:4) led to a significant increase in ThT fluorescence, and the maximal ThT fluorescence was 3-4-fold higher than the control insulin fibril’s ThT fluorescence intensity. Kinetic studies confirm the dose-dependent experimental results. Depending on the concentration of Chobimalt, either (i) no effect is observed, or (ii) significantly, ∼10-times prolonged lag-phases accompanied by the substantial, ∼ 3-fold higher relative ThT fluorescence intensities at the steady-state phase are recorded. In addition, at certain concentrations of Chobimalt, changes in the elongation-phase are noticed. An increase in the Chobimalt concentrations also triggers the formation of insulin fibrils with sharply altered morphological appearance. The fibrils appear to be more flexible and wavy-like with a tendency to form circles. SANS and SAXS data also revealed the morphology changes of amyloid fibrils in the presence of Chobimalt. Amyloid aggregation requires the formation of unfolded intermediates, which subsequently generate amyloidogenic nuclei. We hypothesize that the different morphology of the formed insulin fibrils is the result of the gradual binding of Chobimalt to different binding sites on unfolded insulin. A similar explanation and the existence of such binding sites with different binding energies was shown previously for the nonionic detergent. Thus, the data also emphasize the importance of a protein partially-unfolded state which undergoes the process of fibrils formation; i.e., certain experimental conditions or the presence of additives may dramatically change not only kinetics but also the morphology of fibrillar aggregates.
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Affiliation(s)
- Katarina Siposova
- Department of Biophysics, Institute of Experimental Physics, Slovak Academy of Sciences, Kosice, Slovakia
- *Correspondence: Katarina Siposova, ; Andrey Musatov,
| | - Viktor I. Petrenko
- BCMaterials—Basque Center for Materials, Applications and Nanostructures, Leioa, Spain
- Ikerbasque, Basque Foundation for Science, Bilbao, Spain
| | - Ivana Garcarova
- Department of Biophysics, Institute of Experimental Physics, Slovak Academy of Sciences, Kosice, Slovakia
| | - Dagmar Sedlakova
- Department of Biophysics, Institute of Experimental Physics, Slovak Academy of Sciences, Kosice, Slovakia
| | - László Almásy
- Neutron Spectroscopy Department, Centre for Energy Research, Budapest, Hungary
| | - Olena A. Kyzyma
- Department of Biophysics, Institute of Experimental Physics, Slovak Academy of Sciences, Kosice, Slovakia
- Faculty of Physics, Taras Shevchenko National University of Kyiv, Kyiv, Ukraine
| | - Manfred Kriechbaum
- Institute of Inorganic Chemistry, Graz University of Technology, Graz, Austria
| | - Andrey Musatov
- Department of Biophysics, Institute of Experimental Physics, Slovak Academy of Sciences, Kosice, Slovakia
- *Correspondence: Katarina Siposova, ; Andrey Musatov,
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6
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Retinal hyperspectral imaging in the 5xFAD mouse model of Alzheimer's disease. Sci Rep 2021; 11:6387. [PMID: 33737550 PMCID: PMC7973540 DOI: 10.1038/s41598-021-85554-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 02/20/2021] [Indexed: 11/08/2022] Open
Abstract
Hyperspectral imaging of the retina has recently been posited as a potentially useful form of spectroscopy of amyloid-beta (Aβ) protein in the eyes of those with Alzheimer's disease (AD). The concept of using the retina as a biomarker for AD is an attractive one, as current screening tools for AD are either expensive or inaccessible. Recent studies have investigated hyperspectral imaging in Aβ models however these studies have been in younger mice. Here we characterised hyperspectral reflectance profile in 6 to 17 months old 5xFAD mice and compare this to Aβ in isolated preparations. Hyperspectral imaging was conducted across two preparations of Aβ using a custom built bench ophthalmoscope. In the in vitro condition, 1 mg of purified human Aβ42 was solubilised and left to aggregate for 72 h. This soluble/insoluble Aβ mixture was then imaged by suspending the solution at a pipette tip and compared against phosphate buffered saline (PBS) control (n = 10 ROIs / group). In the in vivo condition, a 5xFAD transgenic mouse model was used and retinae were imaged at the age of 6 (n = 9), 12 (n = 9) and 17 months (n = 8) with age matched wildtype littermates as control (n = 12, n = 13, n = 15 respectively). In the vitro condition, hyperspectral imaging of the solution showed greater reflectance compared with vehicle (p < 0.01), with the greatest differences occurring in the short visible spectrum (< 500 nm). In the in vivo preparation, 5xFAD showed greater hyperspectral reflectance at all ages (6, 12, 17 months, p < 0.01). These differences were noted most in the short wavelengths at younger ages, with an additional peak appearing at longer wavelengths (~ 550 nm) with advancing age. This study shows that the presence of Aβ (soluble/insoluble mixture) can increase the hyperspectral reflectance profile in vitro as well as in vivo. Differences were evident in the short wavelength spectrum (< 500 nm) in vitro and were preserved when imaged through the ocular media in the in vivo conditions. With advancing age a second hump around ~ 550 nm became more apparent. Hyperspectral imaging of the retina does not require the use of contrast agents and is a potentially useful and non-invasive biomarker for AD.
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Windsor PK, Plassmeyer SP, Mattock DS, Bradfield JC, Choi EY, Miller BR, Han BH. Biflavonoid-Induced Disruption of Hydrogen Bonds Leads to Amyloid-β Disaggregation. Int J Mol Sci 2021; 22:ijms22062888. [PMID: 33809196 PMCID: PMC8001082 DOI: 10.3390/ijms22062888] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 03/03/2021] [Accepted: 03/10/2021] [Indexed: 12/12/2022] Open
Abstract
Deposition of amyloid β (Aβ) fibrils in the brain is a key pathologic hallmark of Alzheimer’s disease. A class of polyphenolic biflavonoids is known to have anti-amyloidogenic effects by inhibiting aggregation of Aβ and promoting disaggregation of Aβ fibrils. In the present study, we further sought to investigate the structural basis of the Aβ disaggregating activity of biflavonoids and their interactions at the atomic level. A thioflavin T (ThT) fluorescence assay revealed that amentoflavone-type biflavonoids promote disaggregation of Aβ fibrils with varying potency due to specific structural differences. The computational analysis herein provides the first atomistic details for the mechanism of Aβ disaggregation by biflavonoids. Molecular docking analysis showed that biflavonoids preferentially bind to the aromatic-rich, partially ordered N-termini of Aβ fibril via the π–π interactions. Moreover, docking scores correlate well with the ThT EC50 values. Molecular dynamic simulations revealed that biflavonoids decrease the content of β-sheet in Aβ fibril in a structure-dependent manner. Hydrogen bond analysis further supported that the substitution of hydroxyl groups capable of hydrogen bond formation at two positions on the biflavonoid scaffold leads to significantly disaggregation of Aβ fibrils. Taken together, our data indicate that biflavonoids promote disaggregation of Aβ fibrils due to their ability to disrupt the fibril structure, suggesting biflavonoids as a lead class of compounds to develop a therapeutic agent for Alzheimer’s disease.
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Affiliation(s)
- Peter K. Windsor
- Department of Chemistry, Truman State University, Kirksville, MO 63501, USA; (P.K.W.); (S.P.P.); (D.S.M.); (J.C.B.)
| | - Stephen P. Plassmeyer
- Department of Chemistry, Truman State University, Kirksville, MO 63501, USA; (P.K.W.); (S.P.P.); (D.S.M.); (J.C.B.)
| | - Dominic S. Mattock
- Department of Chemistry, Truman State University, Kirksville, MO 63501, USA; (P.K.W.); (S.P.P.); (D.S.M.); (J.C.B.)
| | - Jonathan C. Bradfield
- Department of Chemistry, Truman State University, Kirksville, MO 63501, USA; (P.K.W.); (S.P.P.); (D.S.M.); (J.C.B.)
| | - Erika Y. Choi
- Department of Pharmacology, A.T. Still University, Kirksville, MO 63501, USA;
| | - Bill R. Miller
- Department of Chemistry, Truman State University, Kirksville, MO 63501, USA; (P.K.W.); (S.P.P.); (D.S.M.); (J.C.B.)
- Correspondence: (B.R.M.III); (B.H.H.)
| | - Byung Hee Han
- Department of Pharmacology, A.T. Still University, Kirksville, MO 63501, USA;
- Correspondence: (B.R.M.III); (B.H.H.)
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8
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Bucciantini M, Leri M, Stefani M, Melki R, Zecchi-Orlandini S, Nosi D. The Amphipathic GM1 Molecule Stabilizes Amyloid Aggregates, Preventing their Cytotoxicity. Biophys J 2020; 119:326-336. [PMID: 32579964 DOI: 10.1016/j.bpj.2020.06.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 05/20/2020] [Accepted: 06/02/2020] [Indexed: 12/20/2022] Open
Abstract
Amyloid aggregates have been demonstrated to exert cytotoxic effects in several diseases. It is widely accepted that the complex and fascinating aggregation pathway involves a series of steps during which many heterogeneous intermediates are generated. This process may be greatly potentiated by the presence of amphipathic components of plasma membrane because they may serve as interaction, condensation, and nucleation points. However, there are few data regarding structural alterations induced by the binding between the amyloid fibrils and membrane components and its direct effects on cell integrity. In this study, we found, by 1-anilinonaphthalene 8-sulfonic acid and transmission electron microscopy/fast Fourier transform, that yeast prion Sup35 oligomers showed higher structural uniformity and altered surface properties when grown in the presence of monosialotetrahexosylganglioside, a component of the cell membrane. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and confocal/sensitized Förster resonance energy transfer analyses revealed that these fibrils showed low cytotoxicity and affinity to plasma membrane. Moreover, time-lapse analysis of Sup35 oligomer fibrillation on cells suggested that the amyloid aggregation process per se exerts cytotoxic effects through the interaction of amyloid intermediates with plasma membrane components. These data provide, to our knowledge, new insights to understand the mechanism of amyloid growth and cytotoxicity in the pathogenesis of amyloid diseases.
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Affiliation(s)
- Monica Bucciantini
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio," University of Florence, Florence, Italy.
| | - Manuela Leri
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio," University of Florence, Florence, Italy; Department of Neuroscience, Psychology, Area of Medicine and Health of the Child of the University of Florence, Florence, Italy
| | - Massimo Stefani
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio," University of Florence, Florence, Italy
| | - Ronald Melki
- Institut Francois Jacob, CEA and Laboratory of Neurodegenerative Diseases, CNRS 92265, Fontenay-Aux-Roses, France
| | | | - Daniele Nosi
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
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Choi EY, Kang SS, Lee SK, Han BH. Polyphenolic Biflavonoids Inhibit Amyloid-Beta Fibrillation and Disaggregate Preformed Amyloid-Beta Fibrils. Biomol Ther (Seoul) 2020; 28:145-151. [PMID: 31697876 PMCID: PMC7059817 DOI: 10.4062/biomolther.2019.113] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 09/14/2019] [Accepted: 09/16/2019] [Indexed: 12/18/2022] Open
Abstract
Alzheimer’s disease (AD) is a devastating neurodegenerative disease and a major cause of dementia in elderly individuals world-wide. Increased deposition of insoluble amyloid β (Aβ) fibrils in the brain is thought be a key neuropathological hallmark of AD. Many recent studies show that natural products such as polyphenolic flavonoids inhibit the formation of insoluble Aβ fibrils and/or destabilize β-sheet-rich Aβ fibrils to form non-cytotoxic aggregates. In the present study, we explored the structure-activity relationship of naturally-occurring biflavonoids on Aβ amyloidogenesis utilizing an in vitro thioflavin T assay with Aβ1–42 peptide which is prone to aggregate more rapidly to fibrils than Aβ1–40 peptide. Among the biflavonoids we tested, we found amentoflavone revealed the most potent effects on inhibiting Aβ1–42 fibrillization (IC50: 0.26 μM), as well as on disassembling preformed Aβ1–42 fibrils (EC50: 0.59 μM). Our structure-activity relationship study suggests that the hydroxyl groups of biflavonoid compounds play an essential role in their molecular interaction with the dynamic process of Aβ1–42 fibrillization. Our atomic force microscopic imaging analysis demonstrates that amentoflavone directly disrupts the fibrillar structure of preformed Aβ1–42 fibrils, resulting in conversion of those fibrils to amorphous Aβ1–42 aggregates. These results indicate that amentoflavone affords the most potent anti-amyloidogenic effects on both inhibition of Aβ1–42 fibrillization and disaggregation of preformed mature Aβ1–42 fibrils.
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Affiliation(s)
- Erika Y Choi
- Department of Pharmacology, A.T. Still University of Health Sciences, Kirksville, MO 63501, USA
| | - Sam Sik Kang
- School of Pharmacy, Seoul National University, Seoul 08826, Republic of Korea
| | - Sang Kook Lee
- School of Pharmacy, Seoul National University, Seoul 08826, Republic of Korea
| | - Byung Hee Han
- Department of Pharmacology, A.T. Still University of Health Sciences, Kirksville, MO 63501, USA
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10
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A Novel pH-Tunable Secondary Conformation Containing Mixed Micellar System in Anticancer Treatment. Cancers (Basel) 2020; 12:cancers12020503. [PMID: 32098177 PMCID: PMC7072654 DOI: 10.3390/cancers12020503] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 02/17/2020] [Accepted: 02/18/2020] [Indexed: 12/12/2022] Open
Abstract
In this study, for the first time, we precisely assembled the poly-γ-benzyl-l-glutamate and an amphiphilic copolymer d-α-tocopherol polyethylene glycol succinate into a mixed micellar system for the embedment of the anticancer drug doxorubicin. Importantly, the intracellular drug-releasing behaviors could be controlled by changing the secondary structures of poly-γ-benzyl-l-glutamate via the precise regulation of the buffer’s pH value. Under neutral conditions, the micellar architectures were stabilized by both α-helix secondary structures and the microcrystalline structures. Under acidic conditions (pH 4.0), the interior structures transformed into a coil state with a disordered alignment, inducing the release of the loaded drug. A remarkable cytotoxicity of the Dox-loaded mixed micelles was exhibited toward human lung cancer cells in vitro. The internalizing capability into the cancer cells, as well as the intracellular drug-releasing behaviors, were also identified and observed. The secondary structures containing Dox-loaded mixed micelles had an outstanding antitumor efficacy in human lung cancer A549 cells-bearing nude mice, while little toxicities occurred or interfered with the hepatic or renal functions after the treatments. Thus, these pH-tunable α-helix-containing mixed micelles are innovative and promising for controlled intracellular anticancer drug delivery.
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11
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Wiglenda T, Groenke N, Hoffmann W, Manz C, Diez L, Buntru A, Brusendorf L, Neuendorf N, Schnoegl S, Haenig C, Schmieder P, Pagel K, Wanker EE. Sclerotiorin Stabilizes the Assembly of Nonfibrillar Abeta42 Oligomers with Low Toxicity, Seeding Activity, and Beta-sheet Content. J Mol Biol 2020; 432:2080-2098. [PMID: 32061932 DOI: 10.1016/j.jmb.2020.01.033] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 01/14/2020] [Accepted: 01/28/2020] [Indexed: 01/21/2023]
Abstract
The self-assembly of the 42-residue amyloid-β peptide, Aβ42, into fibrillar aggregates is associated with neuronal dysfunction and toxicity in Alzheimer's disease (AD) patient brains, suggesting that small molecules acting on this process might interfere with pathogenesis. Here, we present experimental evidence that the small molecule sclerotiorin (SCL), a natural product belonging to the group of azaphilones, potently delays both seeded and nonseeded Aβ42 polymerization in cell-free assays. Mechanistic biochemical studies revealed that the inhibitory effect of SCL on fibrillogenesis is caused by its ability to kinetically stabilize small Aβ42 oligomers. These structures exhibit low β-sheet content and do not possess seeding activity, indicating that SCL acts very early in the amyloid formation cascade before the assembly of seeding-competent, β-sheet-rich fibrillar aggregates. Investigations with NMR WaterLOGSY experiments confirmed the association of Aβ42 assemblies with SCL in solution. Furthermore, using ion mobility-mass spectrometry, we observed that SCL directly interacts with a small fraction of Aβ42 monomers in the gas phase. In comparison to typical amyloid fibrils, small SCL-stabilized Aβ42 assemblies are inefficiently taken up into mammalian cells and have low toxicity in cell-based assays. Overall, these mechanistic studies support a pathological role of stable, β-sheet-rich Aβ42 fibrils in AD, while structures with low β-sheet content may be less relevant.
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Affiliation(s)
- Thomas Wiglenda
- Neuroproteomics, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Nicole Groenke
- Neuroproteomics, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Waldemar Hoffmann
- Institut für Chemie und Biochemie, Freie Universität Berlin, Berlin, Germany
| | - Christian Manz
- Institut für Chemie und Biochemie, Freie Universität Berlin, Berlin, Germany
| | - Lisa Diez
- Neuroproteomics, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Alexander Buntru
- Neuroproteomics, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Lydia Brusendorf
- Neuroproteomics, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Nancy Neuendorf
- Neuroproteomics, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Sigrid Schnoegl
- Neuroproteomics, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Christian Haenig
- Neuroproteomics, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Peter Schmieder
- Leibniz-Institut für Molekulare Pharmakologie, Berlin, Germany
| | - Kevin Pagel
- Institut für Chemie und Biochemie, Freie Universität Berlin, Berlin, Germany
| | - Erich E Wanker
- Neuroproteomics, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany.
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12
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Siposova K, Sedlak E, Kozar T, Nemergut M, Musatov A. Dual effect of non-ionic detergent Triton X-100 on insulin amyloid formation. Colloids Surf B Biointerfaces 2018; 173:709-718. [PMID: 30384267 DOI: 10.1016/j.colsurfb.2018.10.039] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Revised: 10/10/2018] [Accepted: 10/15/2018] [Indexed: 10/28/2022]
Abstract
Atomic force microscopy, Thioflavin T (ThT) fluorescence assay, circular dichroism spectroscopy, differential scanning calorimetry, and molecular modeling techniques have been employed to investigate the amyloid aggregation of insulin in the presence of non-ionic detergent, Triton X-100 (TX-100). In contrast to recently described inhibition of lysozyme amyloid formation by non-ionic detergents (Siposova, 2017), the amyloid aggregation of insulin in the presence of sub-micellar TX-100 concentration exhibits two dissimilar phases. The first, inhibition phase, is observed at the protein to detergent molar ratio of 1:0.1 to 1:1. During this phase, the insulin amyloid fibril formation is inhibited by TX-100 up to ∼60%. The second, "morphological" phase, is observed at increasing detergent concentration, corresponding to protein:detergent molar ratio of ∼1:1 - 1:10. Under these conditions a significant increase of the steady-state ThT fluorescence intensities and a dramatically changed morphology of the insulin fibrils were observed. Increasing of the detergent concentration above the CMC led to complete inhibition of amyloidogenesis. Analysis of the experimental and molecular modeling results suggests an existence of up to six TX-100 binding sites within dimer of insulin with different binding energy. The physiological relevance of the results is discussed.
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Affiliation(s)
- Katarina Siposova
- Department of Biophysics, Institute of Experimental Physics, Slovak Academy of Sciences, Watsonova 47, 040 01, Kosice, Slovakia.
| | - Erik Sedlak
- Center for Interdisciplinary Biosciences, TIP - P.J. Safarik University, Jesenna 5, 041 54, Kosice, Slovakia
| | - Tibor Kozar
- Center for Interdisciplinary Biosciences, TIP - P.J. Safarik University, Jesenna 5, 041 54, Kosice, Slovakia; Laboratory of Information Technologies, Joint Institute for Nuclear Research, Joliot-Curie 6, 141980, Dubna, Moscow Region, Russia
| | - Michal Nemergut
- Department of Biophysics, Faculty of Science, P.J. Safarik University, Jesenna 5, 041 54, Kosice, Slovakia
| | - Andrey Musatov
- Department of Biophysics, Institute of Experimental Physics, Slovak Academy of Sciences, Watsonova 47, 040 01, Kosice, Slovakia
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13
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Österlund N, Kulkarni YS, Misiaszek AD, Wallin C, Krüger DM, Liao Q, Mashayekhy Rad F, Jarvet J, Strodel B, Wärmländer SKTS, Ilag LL, Kamerlin SCL, Gräslund A. Amyloid-β Peptide Interactions with Amphiphilic Surfactants: Electrostatic and Hydrophobic Effects. ACS Chem Neurosci 2018; 9:1680-1692. [PMID: 29683649 DOI: 10.1021/acschemneuro.8b00065] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The amphiphilic nature of the amyloid-β (Aβ) peptide associated with Alzheimer's disease facilitates various interactions with biomolecules such as lipids and proteins, with effects on both structure and toxicity of the peptide. Here, we investigate these peptide-amphiphile interactions by experimental and computational studies of Aβ(1-40) in the presence of surfactants with varying physicochemical properties. Our findings indicate that electrostatic peptide-surfactant interactions are required for coclustering and structure induction in the peptide and that the strength of the interaction depends on the surfactant net charge. Both aggregation-prone peptide-rich coclusters and stable surfactant-rich coclusters can form. Only Aβ(1-40) monomers, but not oligomers, are inserted into surfactant micelles in this surfactant-rich state. Surfactant headgroup charge is suggested to be important as electrostatic peptide-surfactant interactions on the micellar surface seems to be an initiating step toward insertion. Thus, no peptide insertion or change in peptide secondary structure is observed using a nonionic surfactant. The hydrophobic peptide-surfactant interactions instead stabilize the Aβ monomer, possibly by preventing self-interaction between the peptide core and C-terminus, thereby effectively inhibiting the peptide aggregation process. These findings give increased understanding regarding the molecular driving forces for Aβ aggregation and the peptide interaction with amphiphilic biomolecules.
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Affiliation(s)
- Nicklas Österlund
- Department of Biochemistry and Biophysics, Arrhenius Laboratories, Stockholm University, 106 91 Stockholm, Sweden
- Department of Environmental Science and Analytical Chemistry, Arrhenius Laboratories, Stockholm University, 106 91 Stockholm, Sweden
| | - Yashraj S. Kulkarni
- Department of Cell and Molecular Biology, Uppsala University, 751 24 Uppsala, Sweden
| | - Agata D. Misiaszek
- Department of Cell and Molecular Biology, Uppsala University, 751 24 Uppsala, Sweden
| | - Cecilia Wallin
- Department of Biochemistry and Biophysics, Arrhenius Laboratories, Stockholm University, 106 91 Stockholm, Sweden
| | - Dennis M. Krüger
- Department of Cell and Molecular Biology, Uppsala University, 751 24 Uppsala, Sweden
| | - Qinghua Liao
- Department of Cell and Molecular Biology, Uppsala University, 751 24 Uppsala, Sweden
| | - Farshid Mashayekhy Rad
- Department of Environmental Science and Analytical Chemistry, Arrhenius Laboratories, Stockholm University, 106 91 Stockholm, Sweden
| | - Jüri Jarvet
- Department of Biochemistry and Biophysics, Arrhenius Laboratories, Stockholm University, 106 91 Stockholm, Sweden
- The National Institute of Chemical Physics and Biophysics, 12618 Tallinn, Estonia
| | - Birgit Strodel
- Institute of Complex Systems: Structural Biochemistry, Forschungszentrum Jülich, 52425 Jülich, Germany
| | | | - Leopold L. Ilag
- Department of Environmental Science and Analytical Chemistry, Arrhenius Laboratories, Stockholm University, 106 91 Stockholm, Sweden
| | - Shina C. L. Kamerlin
- Department of Cell and Molecular Biology, Uppsala University, 751 24 Uppsala, Sweden
| | - Astrid Gräslund
- Department of Biochemistry and Biophysics, Arrhenius Laboratories, Stockholm University, 106 91 Stockholm, Sweden
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14
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Mohamed T, Gujral SS, Rao PPN. Tau Derived Hexapeptide AcPHF6 Promotes Beta-Amyloid (Aβ) Fibrillogenesis. ACS Chem Neurosci 2018; 9:773-782. [PMID: 29239599 DOI: 10.1021/acschemneuro.7b00433] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
We studied the interactions of a tau derived hexapeptide AcPHF6 with β-amyloid peptides Aβ40 and Aβ42 which reveals its unusual ability to promote Aβ fibrillogenesis. The results demonstrate that the N-acetylated and C-amidated AcPHF6 hexapeptide can cause significant acceleration in Aβ40 and Aβ42 fibril growth. Aggregation kinetic studies at pH 7.4 show that at 25 μM, AcPHF6 hexapeptide was able to cause ∼2.3-fold increase in Aβ40 fibrillogenesis dramatically changing the aggregation kinetics. In addition, AcPHF6 peptide was able to reduce cellular toxicity mediated by Aβ40 and Aβ42 in hippocampal neuronal cell line (HT22). Computational studies suggest that the AcPHF6 peptide can act as an anchor and provides a hydrophobic surface for Aβ monomer to bind and undergo rapid fibrillogenesis to form less toxic fibrils and alter the aggregation kinetics. At the molecular level we propose a "dock-and-pack" mechanism where the AcPHF6 hexapeptide aggregates can stabilize the β-hairpin and promote rapid Aβ self-assembly and growth to form less toxic oligomers or fibrils. Our results have direct implications in designing novel peptide/peptidomimetics as novel pharmacological tools to study protein aggregation and potentially prevent Aβ-mediated toxicity in Alzheimer's disease.
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Affiliation(s)
- Tarek Mohamed
- School of Pharmacy, Health Sciences Campus, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, Canada N2L 3G1
| | - Sarbjeet Singh Gujral
- School of Pharmacy, Health Sciences Campus, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, Canada N2L 3G1
| | - Praveen P. N. Rao
- School of Pharmacy, Health Sciences Campus, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, Canada N2L 3G1
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15
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Al-Shabib NA, Khan JM, Malik A, Alsenaidy AM, Alsenaidy MA, Husain FM, Shamsi MB, Hidayathulla S, Khan RH. Negatively charged food additive dye “Allura Red” rapidly induces SDS-soluble amyloid fibril in beta-lactoglobulin protein. Int J Biol Macromol 2018; 107:1706-1716. [DOI: 10.1016/j.ijbiomac.2017.10.032] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2017] [Revised: 10/02/2017] [Accepted: 10/06/2017] [Indexed: 10/18/2022]
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16
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Detergent-induced aggregation of an amyloidogenic intrinsically disordered protein. J CHEM SCI 2017. [DOI: 10.1007/s12039-017-1386-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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17
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Cieplak AS. Protein folding, misfolding and aggregation: The importance of two-electron stabilizing interactions. PLoS One 2017; 12:e0180905. [PMID: 28922400 PMCID: PMC5603215 DOI: 10.1371/journal.pone.0180905] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2017] [Accepted: 06/22/2017] [Indexed: 12/17/2022] Open
Abstract
Proteins associated with neurodegenerative diseases are highly pleiomorphic and may adopt an all-α-helical fold in one environment, assemble into all-β-sheet or collapse into a coil in another, and rapidly polymerize in yet another one via divergent aggregation pathways that yield broad diversity of aggregates’ morphology. A thorough understanding of this behaviour may be necessary to develop a treatment for Alzheimer’s and related disorders. Unfortunately, our present comprehension of folding and misfolding is limited for want of a physicochemical theory of protein secondary and tertiary structure. Here we demonstrate that electronic configuration and hyperconjugation of the peptide amide bonds ought to be taken into account to advance such a theory. To capture the effect of polarization of peptide linkages on conformational and H-bonding propensity of the polypeptide backbone, we introduce a function of shielding tensors of the Cα atoms. Carrying no information about side chain-side chain interactions, this function nonetheless identifies basic features of the secondary and tertiary structure, establishes sequence correlates of the metamorphic and pH-driven equilibria, relates binding affinities and folding rate constants to secondary structure preferences, and manifests common patterns of backbone density distribution in amyloidogenic regions of Alzheimer’s amyloid β and tau, Parkinson’s α-synuclein and prions. Based on those findings, a split-intein like mechanism of molecular recognition is proposed to underlie dimerization of Aβ, tau, αS and PrPC, and divergent pathways for subsequent association of dimers are outlined; a related mechanism is proposed to underlie formation of PrPSc fibrils. The model does account for: (i) structural features of paranuclei, off-pathway oligomers, non-fibrillar aggregates and fibrils; (ii) effects of incubation conditions, point mutations, isoform lengths, small-molecule assembly modulators and chirality of solid-liquid interface on the rate and morphology of aggregation; (iii) fibril-surface catalysis of secondary nucleation; and (iv) self-propagation of infectious strains of mammalian prions.
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Affiliation(s)
- Andrzej Stanisław Cieplak
- Department of Chemistry, Bilkent University, Ankara, Turkey
- Department of Chemistry, Yale University, New Haven, Connecticut, United States of America
- Department of Chemistry, Brandeis University, Waltham, Massachusetts, United States of America
- * E-mail:
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18
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Thioflavin T fluorescence to analyse amyloid formation kinetics: Measurement frequency as a factor explaining irreproducibility. Anal Biochem 2017. [DOI: 10.1016/j.ab.2017.06.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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19
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Proteins behaving badly. Substoichiometric molecular control and amplification of the initiation and nature of amyloid fibril formation: lessons from and for blood clotting. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2017; 123:16-41. [DOI: 10.1016/j.pbiomolbio.2016.08.006] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2016] [Revised: 08/14/2016] [Accepted: 08/19/2016] [Indexed: 02/08/2023]
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20
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Siposova K, Kozar T, Musatov A. Interaction of nonionic detergents with the specific sites of lysozyme amyloidogenic region - inhibition of amyloid fibrillization. Colloids Surf B Biointerfaces 2016; 150:445-455. [PMID: 27842932 DOI: 10.1016/j.colsurfb.2016.11.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 11/02/2016] [Accepted: 11/05/2016] [Indexed: 11/15/2022]
Abstract
Two nonionic detergents, Triton X-100 (TX-100) and n-dodecyl-β-d-maltoside (DDM) were tested for their ability to affect lysozyme amyloid aggregation. We have demonstrated that fibrillization of lysozyme is completely inhibited by low sub-micellar concentrations of both of these detergents. The apparent IC50 values were calculated to be 22μM and 26μM for TX-100 and DDM, respectively. The detergent/protein ratio is not the only parameter controlling inhibition. The precise timing of the detergent addition was found to be also crucial. It appears that the primary inhibitory activity of detergents resulted from inhibition of nuclei formation, in addition to inhibition of fibril polymerization at the early stage of protofibrils growth. The docking study revealed that Asn-59, Trp-63 and Ala-107, all present within the lysozyme amyloidogenic region, were involved in the interaction with both detergents. In addition, TX-100 also interacted with Gln-57 and Asp-103 within lysozyme. Moreover, based on our computational results, TX-100 bridges the Gln-57 and Ala-107 amino acids of the amyloidogenic segment of lysozyme and therefore inhibits more effectively the amyloid fibril formation. Along these lines, the knowledge gained from our study indicates that the detergents or their derivatives may be applicable as a promising strategy for the modulation of lysozyme protein aggregation.
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Affiliation(s)
- Katarina Siposova
- Department of Biophysics, Institute of Experimental Physics, Slovak Academy of Sciences, Watsonova 47, 040 01 Kosice, Slovakia.
| | - Tibor Kozar
- Center for multimodal imaging, Institute of Physics, Faculty of Science, P.J. Safarik University, Srobarova 2, 041 54 Kosice, Slovakia
| | - Andrey Musatov
- Department of Biophysics, Institute of Experimental Physics, Slovak Academy of Sciences, Watsonova 47, 040 01 Kosice, Slovakia
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21
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β-Amyloid-acetylcholine molecular interaction: new role of cholinergic mediators in anti-Alzheimer therapy? Future Med Chem 2016; 8:1179-89. [PMID: 27402297 DOI: 10.4155/fmc-2016-0006] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
BACKGROUND For long time Alzheimer's disease has been attributed to a cholinergic deficit. More recently, it has been considered dependent on the accumulation of the amyloid beta peptide (Aβ), which promotes neuronal loss and impairs neuronal function. Results/methodology: In the present study, using biophysical and biochemical experiments we tested the hypothesis that in addition to its role as a neurotransmitter, acetylcholine may exert its action as an anti-Alzheimer agent through a direct interaction with Aβ. CONCLUSION Our data provide evidence that acetylcholine favors the soluble peptide conformation and exerts a neuroprotective effect against the neuroinflammatory and toxic effects of Aβ. The present paper paves the way toward the development of new polyfunctional anti-Alzheimer therapeutics capable of intervening on both the cholinergic transmission and the Aβ aggregation.
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22
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Nokwe CN, Hora M, Zacharias M, Yagi H, Peschek J, Reif B, Goto Y, Buchner J. A Stable Mutant Predisposes Antibody Domains to Amyloid Formation through Specific Non-Native Interactions. J Mol Biol 2016; 428:1315-1332. [DOI: 10.1016/j.jmb.2016.01.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Revised: 01/10/2016] [Accepted: 01/15/2016] [Indexed: 12/17/2022]
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23
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Ryan TM, Griffin MDW, McGillivray DJ, Knott RB, Wood K, Masters CL, Kirby N, Curtain CC. Apolipoprotein C-II Adopts Distinct Structures in Complex with Micellar and Submicellar Forms of the Amyloid-Inhibiting Lipid-Mimetic Dodecylphosphocholine. Biophys J 2016; 110:85-94. [PMID: 26745412 PMCID: PMC4805880 DOI: 10.1016/j.bpj.2015.11.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Revised: 11/03/2015] [Accepted: 11/09/2015] [Indexed: 01/21/2023] Open
Abstract
The formation of amyloid deposits is a common feature of a broad range of diseases, including atherosclerosis, Alzheimer's disease, and Parkinson's disease. The basis and role of amyloid deposition in the pathogenesis of these diseases is still being defined, however an interesting feature of amyloidogenic proteins is that the majority of the pathologically associated proteins are involved in lipid homeostasis, be it in lipid transport, incorporation into membranes, or the regulation of lipid pathways. Thus, amyloid-forming proteins commonly bind lipids, and lipids are generally involved in the proper folding of these proteins. However, understanding of the basis for these lipid-related aspects of amyloidogenesis is lacking. Thus, we have used the apolipoprotein C-II amyloid model system in conjunction with x-ray and neutron scattering analyses to address this problem. Apolipoprotein C-II is a well-studied model system of systemic amyloid fibril formation, with a clear and well-defined pathway for fibril formation, where the effects of lipid interaction are characterized, particularly for the lipid mimetic dodecylphosphocholine. We show that the micellar state of an inhibitory lipid can have a very significant effect on protein conformation, with micelles stabilizing a particular α-helical structure, whereas submicellar lipids stabilize a very different dimeric, α-helical structure. These results indicate that lipids may have an important role in the development and progression of amyloid-related diseases.
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Affiliation(s)
- Timothy M Ryan
- Australian Synchrotron, Clayton, Victoria, Australia; The Florey Institute, The University of Melbourne, Parkville, Victoria, Australia; The MacDiarmid Institute of Advanced Materials and Nanotechnology, Wellington, New Zealand.
| | - Michael D W Griffin
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria, Australia
| | - Duncan J McGillivray
- School of Chemical Science, The University of Auckland, Auckland, New Zealand; The MacDiarmid Institute of Advanced Materials and Nanotechnology, Wellington, New Zealand
| | - Robert B Knott
- Australian Nuclear Science and Technology Organisation, New South Wales, Australia
| | - Kathleen Wood
- Australian Nuclear Science and Technology Organisation, New South Wales, Australia
| | - Colin L Masters
- The Florey Institute, The University of Melbourne, Parkville, Victoria, Australia
| | - Nigel Kirby
- Australian Synchrotron, Clayton, Victoria, Australia
| | - Cyril C Curtain
- The Florey Institute, The University of Melbourne, Parkville, Victoria, Australia
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24
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Controllable Phase Separation by Boc-Modified Lipophilic Acid as a Multifunctional Extractant. Sci Rep 2015; 5:17509. [PMID: 26627307 PMCID: PMC4667251 DOI: 10.1038/srep17509] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 10/21/2015] [Indexed: 11/29/2022] Open
Abstract
While phase separation of immiscible liquid-liquid systems has become increasingly significant in diverse areas, the irreversible nature limits their further application in controllable extraction-concentration or capture-release fields. There is a need for the development of simple, efficient and reversible methods for numerous research and industrial extraction and separation applications. We envisioned Boc-modified lipophilic acids as a simple model for such use based on the studies of the multi-phase transitions of Boc-modified supramolecular polymeric systems. Here, we demonstrate that in the presence of Boc-7-aminoheptanoic acid (Boc-7), phase separation occurs in mixtures of miscible organic solvent and water. The separation behavior was confirmed by differential colorimetric development in aqueous and organic phases using methyl orange staining assays. Component substitution experiments verified that the phase separation results from the subtle balance between the aggregation and the solvation forces of Boc-7, and is reversible by adjusting the solution pH. Owing to the intrinsic hydrophobic properties of the organic phase and the hydrogen bonding-forming ability of the carboxyl group of Boc-7, the phase separation system captures and releases Sudan Red, fluorescein, and streptavidin in a controllable manner. Consequently, a reversible and simple phase separation system can be designed as a multifunctional extractant.
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25
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Teoh CL, Su D, Sahu S, Yun SW, Drummond E, Prelli F, Lim S, Cho S, Ham S, Wisniewski T, Chang YT. Chemical Fluorescent Probe for Detection of Aβ Oligomers. J Am Chem Soc 2015; 137:13503-9. [PMID: 26218347 PMCID: PMC4756585 DOI: 10.1021/jacs.5b06190] [Citation(s) in RCA: 132] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Aggregation of amyloid β-peptide (Aβ) is implicated in the pathology of Alzheimer's disease (AD), with the soluble, Aβ oligomeric species thought to be the critical pathological species. Identification and characterization of intermediate species formed during the aggregation process is crucial to the understanding of the mechanisms by which oligomeric species mediate neuronal toxicity and following disease progression. Probing these species proved to be extremely challenging, as evident by the lack of reliable sensors, due to their heterogeneous and transient nature. We describe here an oligomer-specific fluorescent chemical probe, BoDipy-Oligomer (BD-Oligo), developed through the use of the diversity-oriented fluorescent library approach (DOFLA) and high-content, imaging-based screening. This probe enables dynamic oligomer monitoring during fibrillogenesis in vitro and shows in vivo Aβ oligomers staining possibility in the AD mice model.
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Affiliation(s)
- Chai Lean Teoh
- Laboratory of Bioimaging Probe Development, Singapore Bioimaging Consortium (SBIC), Agency for Science, Technology and Research (A*STAR), 11 Biopolis Way, 02-02 Helios, Biopolis, Singapore 138667, Singapore
| | - Dongdong Su
- Laboratory of Bioimaging Probe Development, Singapore Bioimaging Consortium (SBIC), Agency for Science, Technology and Research (A*STAR), 11 Biopolis Way, 02-02 Helios, Biopolis, Singapore 138667, Singapore
| | - Srikanta Sahu
- Laboratory of Bioimaging Probe Development, Singapore Bioimaging Consortium (SBIC), Agency for Science, Technology and Research (A*STAR), 11 Biopolis Way, 02-02 Helios, Biopolis, Singapore 138667, Singapore
| | - Seong-Wook Yun
- Laboratory of Bioimaging Probe Development, Singapore Bioimaging Consortium (SBIC), Agency for Science, Technology and Research (A*STAR), 11 Biopolis Way, 02-02 Helios, Biopolis, Singapore 138667, Singapore
| | - Eleanor Drummond
- Department of Neurology and the Center for Cognitive Neurology, New York University School of Medicine, Alexandria ERSP, Room 802, 450 East 29th Street, New York, New York 10016, United States
| | - Frances Prelli
- Department of Neurology and the Center for Cognitive Neurology, New York University School of Medicine, Alexandria ERSP, Room 802, 450 East 29th Street, New York, New York 10016, United States
| | - Sulgi Lim
- Department of Chemistry and the Center for Fluctuating Thermodynamics, Sookmyung Women’s University, Cheongpa-ro 47-gil 100, Yongsan-Ku, Seoul 140-742, Korea
| | - Sunhee Cho
- Department of Chemistry and the Center for Fluctuating Thermodynamics, Sookmyung Women’s University, Cheongpa-ro 47-gil 100, Yongsan-Ku, Seoul 140-742, Korea
| | - Sihyun Ham
- Department of Chemistry and the Center for Fluctuating Thermodynamics, Sookmyung Women’s University, Cheongpa-ro 47-gil 100, Yongsan-Ku, Seoul 140-742, Korea
| | - Thomas Wisniewski
- Departments of Neurology, Pathology and Psychiatry and the Center for Cognitive Neurology, New York University School of Medicine, Alexandria ERSP, Room 802, 450 East 29th Street, New York, New York 10016, United States
| | - Young-Tae Chang
- Laboratory of Bioimaging Probe Development, Singapore Bioimaging Consortium (SBIC), Agency for Science, Technology and Research (A*STAR), 11 Biopolis Way, 02-02 Helios, Biopolis, Singapore 138667, Singapore
- Department of Chemistry and MedChem Program, Life Sciences Institute, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore
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So M, Ishii A, Hata Y, Yagi H, Naiki H, Goto Y. Supersaturation-Limited and Unlimited Phase Spaces Compete to Produce Maximal Amyloid Fibrillation near the Critical Micelle Concentration of Sodium Dodecyl Sulfate. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:9973-9982. [PMID: 26291985 DOI: 10.1021/acs.langmuir.5b02186] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Although various natural and synthetic compounds have been shown to accelerate or inhibit the formation of amyloid fibrils, the mechanisms by which they achieve these adverse effects in a concentration-dependent manner currently remain unclear. Sodium dodecyl sulfate (SDS), one of the compounds that has adverse effects on fibrillation, is the most intensively studied. Here we examined the effects of a series of detergents including SDS on the amyloid fibrillation of β2-microglobulin at pH 7.0, a protein responsible for dialysis-related amyloidosis. In all the detergents examined (i.e., SDS, sodium decyl sulfate, sodium octyl sulfate, and sodium deoxycholate), amyloid fibrillation was accelerated and inhibited at concentrations near the critical micelle concentration (CMC) and higher than CMC, respectively. The most stable conformation changed from monomers with a β-structure to amyloid fibrils with a β-structure and then to α-helical complexes with micelles with an increase in detergent concentrations. These results suggest that competition between supersaturation-limited fibrillation and unlimited mixed micelle formation between proteins and micelles underlies the detergent concentration-dependent complexity of amyloid fibrillation.
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Affiliation(s)
- Masatomo So
- Institute for Protein Research, Osaka University , Osaka 565-0871, Japan
| | - Akira Ishii
- Institute for Protein Research, Osaka University , Osaka 565-0871, Japan
| | - Yasuko Hata
- Institute for Protein Research, Osaka University , Osaka 565-0871, Japan
| | - Hisashi Yagi
- Institute for Protein Research, Osaka University , Osaka 565-0871, Japan
| | - Hironobu Naiki
- Faculty of Medical Science, University of Fukui , Fukui 910-1193, Japan
| | - Yuji Goto
- Institute for Protein Research, Osaka University , Osaka 565-0871, Japan
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27
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Porzoor A, Alford B, Hügel HM, Grando D, Caine J, Macreadie I. Anti-amyloidogenic properties of some phenolic compounds. Biomolecules 2015; 5:505-27. [PMID: 25898401 PMCID: PMC4496683 DOI: 10.3390/biom5020505] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Revised: 04/02/2015] [Accepted: 04/03/2015] [Indexed: 12/23/2022] Open
Abstract
A family of 21 polyphenolic compounds consisting of those found naturally in danshen and their analogues were synthesized and subsequently screened for their anti-amyloidogenic activity against the amyloid beta peptide (Aβ42) of Alzheimer’s disease. After 24 h incubation with Aβ42, five compounds reduced thioflavin T (ThT) fluorescence, indicative of their anti-amyloidogenic propensity (p < 0.001). TEM and immunoblotting analysis also showed that selected compounds were capable of hindering fibril formation even after prolonged incubations. These compounds were also capable of rescuing the yeast cells from toxic changes induced by the chemically synthesized Aβ42. In a second assay, a Saccharomyces cerevisiae AHP1 deletant strain transformed with GFP fused to Aβ42 was treated with these compounds and analyzed by flow cytometry. There was a significant reduction in the green fluorescence intensity associated with 14 compounds. We interpret this result to mean that the compounds had an anti-amyloid-aggregation propensity in the yeast and GFP-Aβ42 was removed by proteolysis. The position and not the number of hydroxyl groups on the aromatic ring was found to be the most important determinant for the anti-amyloidogenic properties.
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Affiliation(s)
- Afsaneh Porzoor
- School of Applied Sciences, RMIT University, Bundoora, Victoria 3083, Australia.
| | - Benjamin Alford
- School of Applied Sciences, RMIT University, Melbourne, Victoria 3000, Australia.
| | - Helmut M Hügel
- School of Applied Sciences, RMIT University, Melbourne, Victoria 3000, Australia.
| | - Danilla Grando
- School of Applied Sciences, RMIT University, Bundoora, Victoria 3083, Australia.
| | - Joanne Caine
- Materials Science and Engineering, CSIRO Preventative Health Flagship, 343 Royal Parade, Parkville, Victoria 3052, Australia.
| | - Ian Macreadie
- School of Applied Sciences, RMIT University, Bundoora, Victoria 3083, Australia.
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28
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Stabilization of nontoxic Aβ-oligomers: insights into the mechanism of action of hydroxyquinolines in Alzheimer's disease. J Neurosci 2015; 35:2871-84. [PMID: 25698727 DOI: 10.1523/jneurosci.2912-14.2015] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The extracellular accumulation of amyloid β (Aβ) peptides is characteristic of Alzheimer's disease (AD). However, formation of diffusible, oligomeric forms of Aβ, both on and off pathways to amyloid fibrils, is thought to include neurotoxic species responsible for synaptic loss and neurodegeneration, rather than polymeric amyloid aggregates. The 8-hydroxyquinolines (8-HQ) clioquinol (CQ) and PBT2 were developed for their ability to inhibit metal-mediated generation of reactive oxygen species from Aβ:Cu complexes and have both undergone preclinical and Phase II clinical development for the treatment of AD. Their respective modes of action are not fully understood and may include both inhibition of Aβ fibrillar polymerization and direct depolymerization of existing Aβ fibrils. In the present study, we find that CQ and PBT2 can interact directly with Aβ and affect its propensity to aggregate. Using a combination of biophysical techniques, we demonstrate that, in the presence of these 8-HQs and in the absence of metal ions, Aβ associates with two 8-HQ molecules and forms a dimer. Furthermore, 8-HQ bind Aβ with an affinity of 1-10 μm and suppress the formation of large (>30 kDa) oligomers. The stabilized low molecular weight species are nontoxic. Treatment with 8-HQs also reduces the levels of in vivo soluble oligomers in a Caenorhabditis elegans model of Aβ toxicity. We propose that 8-HQs possess an additional mechanism of action that neutralizes neurotoxic Aβ oligomer formation through stabilization of small (dimeric) nontoxic Aβ conformers.
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29
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Martins AF, Dias DM, Morfin JF, Lacerda S, Laurents DV, Tóth É, Geraldes CFGC. Interaction of PiB-Derivative Metal Complexes with Beta-Amyloid Peptides: Selective Recognition of the Aggregated Forms. Chemistry 2015; 21:5413-22. [DOI: 10.1002/chem.201406152] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Indexed: 01/03/2023]
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30
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The Role of Lipid in Misfolding and Amyloid Fibril Formation by Apolipoprotein C-II. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2015; 855:157-74. [DOI: 10.1007/978-3-319-17344-3_7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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31
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Watt AD, Crespi GAN, Down RA, Ascher DB, Gunn A, Perez KA, McLean CA, Villemagne VL, Parker MW, Barnham KJ, Miles LA. Anti-Aβ antibody target engagement: a response to Siemers et al. Acta Neuropathol 2014; 128:611-4. [PMID: 25120193 DOI: 10.1007/s00401-014-1333-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Accepted: 08/07/2014] [Indexed: 10/24/2022]
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32
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Drolle E, Hane F, Lee B, Leonenko Z. Atomic force microscopy to study molecular mechanisms of amyloid fibril formation and toxicity in Alzheimer's disease. Drug Metab Rev 2014; 46:207-23. [PMID: 24495298 DOI: 10.3109/03602532.2014.882354] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Alzheimer's disease (AD) is a devastating neurodegenerative disease characterized by dementia and memory loss for which no cure or effective prevention is currently available. Neurodegeneration in AD is linked to formation of amyloid plaques found in brain tissues of Alzheimer's patients during post-mortem examination. Amyloid plaques are composed of amyloid fibrils and small oligomers - insoluble protein aggregates. Although amyloid plaques are found on the neuronal cell surfaces, the mechanism of amyloid toxicity is still not well understood. Currently, it is believed that the cytotoxicity is a result of the nonspecific interaction of small soluble amyloid oligomers (rather than longer fibrils) with the plasma membrane. In recent years, nanotechnology has contributed significantly to understanding the structure and function of lipid membranes and to the study of the molecular mechanisms of membrane-associated diseases. We review the current state of research, including applications of the latest nanotechnology approaches, on the interaction of lipid membranes with the amyloid-β (Aβ) peptide in relation to amyloid toxicity. We discuss the interactions of Aβ with model lipid membranes with a focus to demonstrate that composition, charge and phase of the lipid membrane, as well as lipid domains and rafts, affect the binding of Aβ to the membrane and contribute to toxicity. Understanding the role of the lipid membrane in AD at the nanoscale and molecular level will contribute to the understanding of the molecular mechanism of amyloid toxicity and may aid into the development of novel preventive strategies to combat AD.
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Affiliation(s)
- Elizabeth Drolle
- Department of Biology, University of Waterloo , Waterloo, ON , Canada
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33
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Yu M, Ryan TM, Ellis S, Bush AI, Triccas JA, Rutledge PJ, Todd MH. Neuroprotective peptide–macrocycle conjugates reveal complex structure–activity relationships in their interactions with amyloid β. Metallomics 2014; 6:1931-40. [DOI: 10.1039/c4mt00122b] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Novel neuroprotective peptide–macrocycle conjugates exhibit complex, multifaceted structure–activity relationships in their interactions with amyloid β.
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Affiliation(s)
- Mingfeng Yu
- School of Chemistry
- The University of Sydney
- Sydney, Australia
| | - Timothy M. Ryan
- The Florey Institute of Neuroscience and Mental Health
- Parkville, Australia
| | - Samantha Ellis
- Sydney Medical School
- The University of Sydney
- Sydney, Australia
| | - Ashley I. Bush
- The Florey Institute of Neuroscience and Mental Health
- Parkville, Australia
| | | | | | - Matthew H. Todd
- School of Chemistry
- The University of Sydney
- Sydney, Australia
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34
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Grasso GI, Arena G, Bellia F, Rizzarelli E, Vecchio G. Copper(II)-chelating homocarnosine glycoconjugate as a new multifunctional compound. J Inorg Biochem 2013; 131:56-63. [PMID: 24246303 DOI: 10.1016/j.jinorgbio.2013.10.020] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Revised: 10/23/2013] [Accepted: 10/23/2013] [Indexed: 10/26/2022]
Abstract
Homocarnosine is an endogenous dipeptide distributed in cerebral regions and cerebrospinal fluid. Homocarnosine may serve as an antioxidant, free radical scavenger, neurotransmitter, buffering system and metal chelating agent, especially for copper(II) and zinc(II). The homeostasis of homocarnosine is regulated by carnosinases; the serum-circulating isoform of these metallodipeptidases partially hydrolyses homocarnosine in the blood. The enzyme activity is also inhibited by homocarnosine itself in a dose-dependent manner. We synthesized a new multifunctional homocarnosine derivative with trehalose, a disaccharide that possesses several beneficial properties, among which the inhibition of protein aggregation (i.e. Aβ amyloid and polyglutamine proteins) involved in widespread neurodegenerative disorders. We studied the copper(II) binding features of the new conjugate by means of potentiometric and spectroscopic techniques (UV-visible and circular dichroism) and the superoxide dismutase-like activity of the copper(II) complexes with homocarnosine and its trehalose conjugate was evaluated. The inhibitory effect of the new homocarnosine derivative on the carnosinase activity and its effects on Aβ aggregation were also investigated.
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Affiliation(s)
- Giuseppa I Grasso
- Institute of Biostructure and Bioimaging, National Research Council (CNR), Viale A. Doria 6, Catania, Italy
| | - Giuseppe Arena
- Department of Chemical Sciences, University of Catania, Viale A. Doria 6, Catania, Italy
| | - Francesco Bellia
- Institute of Biostructure and Bioimaging, National Research Council (CNR), Viale A. Doria 6, Catania, Italy.
| | - Enrico Rizzarelli
- Institute of Biostructure and Bioimaging, National Research Council (CNR), Viale A. Doria 6, Catania, Italy; Department of Chemical Sciences, University of Catania, Viale A. Doria 6, Catania, Italy
| | - Graziella Vecchio
- Department of Chemical Sciences, University of Catania, Viale A. Doria 6, Catania, Italy
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35
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Lockhart C, Klimov DK. Revealing Hidden Helix Propensity in Aβ Peptides by Molecular Dynamics Simulations. J Phys Chem B 2013; 117:12030-8. [DOI: 10.1021/jp407705j] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Christopher Lockhart
- School
of Systems Biology, George Mason University, Manassas, Virginia 20110, United States
| | - Dmitri K. Klimov
- School
of Systems Biology, George Mason University, Manassas, Virginia 20110, United States
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36
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Molecular interactions of Alzheimer's biomarker FDDNP with Aβ peptide. Biophys J 2013; 103:2341-51. [PMID: 23283233 DOI: 10.1016/j.bpj.2012.10.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Revised: 09/29/2012] [Accepted: 10/03/2012] [Indexed: 12/28/2022] Open
Abstract
All-atom explicit solvent model and replica exchange molecular dynamics were used to investigate binding of Alzheimer's biomarker FDDNP to the Aβ(10-40) monomer. At low and high concentrations, FDDNP binds with high affinity to two sites in the Aβ(10-40) monomer located near the central hydrophobic cluster and in the C-terminal. Analysis of ligand- Aβ(10-40) interactions at both concentrations identifies hydrophobic effect as a main binding factor. However, with the increase in ligand concentration the interactions between FDDNP molecules also become important due to strong FDDNP self-aggregation propensity and few specific binding locations. As a result, FDDNP ligands partially penetrate the core of the Aβ(10-40) monomer, forming large self-aggregated clusters. Ligand self-aggregation does not affect hydrophobic interactions as a main binding factor or the location of binding sites in Aβ(10-40). Using the Aβ(10-40) conformational ensemble in ligand-free water as reference, we show that FDDNP induces minor changes in the Aβ(10-40) secondary structure at two ligand concentrations studied. At the same time, FDDNP significantly alters the peptide tertiary fold in a concentration-dependent manner by redistributing long-range, side-chain interactions. We argue that because FDDNP does not change Aβ(10-40) secondary structure, its antiaggregation effect is likely to be weak. Our study raises the possibility that FDDNP may serve as a biomarker of not only Aβ fibril species, but of monomers as well.
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37
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Ryan TM, Caine J, Mertens HDT, Kirby N, Nigro J, Breheney K, Waddington LJ, Streltsov VA, Curtain C, Masters CL, Roberts BR. Ammonium hydroxide treatment of Aβ produces an aggregate free solution suitable for biophysical and cell culture characterization. PeerJ 2013; 1:e73. [PMID: 23678397 PMCID: PMC3646356 DOI: 10.7717/peerj.73] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2012] [Accepted: 04/22/2013] [Indexed: 11/20/2022] Open
Abstract
Alzheimer's disease is the leading cause of dementia in the elderly. Pathologically it is characterized by the presence of amyloid plaques and neuronal loss within the brain tissue of affected individuals. It is now widely hypothesised that fibrillar structures represent an inert structure. Biophysical and toxicity assays attempting to characterize the formation of both the fibrillar and the intermediate oligomeric structures of Aβ typically involves preparing samples which are largely monomeric; the most common method by which this is achieved is to use the fluorinated organic solvent 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP). Recent evidence has suggested that this method is not 100% effective in producing an aggregate free solution. We show, using dynamic light scattering, size exclusion chromatography and small angle X-ray scattering that this is indeed the case, with HFIP pretreated Aβ peptide solutions displaying an increased proportion of oligomeric and aggregated material and an increased propensity to aggregate. Furthermore we show that an alternative technique, involving treatment with strong alkali results in a much more homogenous solution that is largely monomeric. These techniques for solubilising and controlling the oligomeric state of Aβ are valuable starting points for future biophysical and toxicity assays.
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Affiliation(s)
- Timothy M Ryan
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne , Parkville, Victoria , Australia
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38
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Lockhart C, Kim S, Klimov DK. Explicit Solvent Molecular Dynamics Simulations of Aβ Peptide Interacting with Ibuprofen Ligands. J Phys Chem B 2012; 116:12922-32. [DOI: 10.1021/jp306208n] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Christopher Lockhart
- School of Systems Biology, George Mason University, Manassas, Virginia 20110, United States
| | - Seongwon Kim
- School of Systems Biology, George Mason University, Manassas, Virginia 20110, United States
| | - Dmitri K. Klimov
- School of Systems Biology, George Mason University, Manassas, Virginia 20110, United States
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