1
|
Chung CW, Stephens AD, Konno T, Ward E, Avezov E, Kaminski CF, Hassanali AA, Kaminski Schierle GS. Intracellular Aβ42 Aggregation Leads to Cellular Thermogenesis. J Am Chem Soc 2022; 144:10034-10041. [PMID: 35616634 PMCID: PMC9185738 DOI: 10.1021/jacs.2c03599] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
The aggregation of
Aβ42 is a hallmark of Alzheimer’s
disease. It is still not known what the biochemical changes are inside
a cell which will eventually lead to Aβ42 aggregation. Thermogenesis
has been associated with cellular stress, the latter of which may
promote aggregation. We perform intracellular thermometry measurements
using fluorescent polymeric thermometers to show that Aβ42 aggregation
in live cells leads to an increase in cell-averaged temperatures.
This rise in temperature is mitigated upon treatment with an aggregation
inhibitor of Aβ42 and is independent of mitochondrial damage
that can otherwise lead to thermogenesis. With this, we present a
diagnostic assay which could be used to screen small-molecule inhibitors
to amyloid proteins in physiologically relevant settings. To interpret
our experimental observations and motivate the development of future
models, we perform classical molecular dynamics of model Aβ
peptides to examine the factors that hinder thermal dissipation. We
observe that this is controlled by the presence of ions in its surrounding
environment, the morphology of the amyloid peptides, and the extent
of its hydrogen-bonding interactions with water. We show that aggregation
and heat retention by Aβ peptides are favored under intracellular-mimicking
ionic conditions, which could potentially promote thermogenesis. The
latter will, in turn, trigger further nucleation events that accelerate
disease progression.
Collapse
Affiliation(s)
- Chyi Wei Chung
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Philippa Fawcett Drive, Cambridge CB3 0AS, U.K
| | - Amberley D Stephens
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Philippa Fawcett Drive, Cambridge CB3 0AS, U.K
| | - Tasuku Konno
- UK Dementia Research Institute, Department of Clinical Neuroscience, University of Cambridge, Cambridge CB2 0AH, U.K
| | - Edward Ward
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Philippa Fawcett Drive, Cambridge CB3 0AS, U.K
| | - Edward Avezov
- UK Dementia Research Institute, Department of Clinical Neuroscience, University of Cambridge, Cambridge CB2 0AH, U.K
| | - Clemens F Kaminski
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Philippa Fawcett Drive, Cambridge CB3 0AS, U.K
| | - Ali A Hassanali
- Condensed Matter and Statistical Physics, International Centre for Theoretical Physics, Strada Costiera 11, Trieste 34151, Italy
| | - Gabriele S Kaminski Schierle
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Philippa Fawcett Drive, Cambridge CB3 0AS, U.K
| |
Collapse
|
2
|
Gabryelczyk B, Alag R, Philips M, Low K, Venkatraman A, Kannaian B, Shi X, Linder M, Pervushin K, Miserez A. In vivo liquid–liquid phase separation protects amyloidogenic and aggregation‐prone peptides during overexpression in
Escherichia coli
. Protein Sci 2022; 31:e4292. [PMID: 35481658 PMCID: PMC8994509 DOI: 10.1002/pro.4292] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 02/03/2022] [Accepted: 02/22/2022] [Indexed: 12/13/2022]
Abstract
Studying pathogenic effects of amyloids requires homogeneous amyloidogenic peptide samples. Recombinant production of these peptides is challenging due to their susceptibility to aggregation and chemical modifications. Thus, chemical synthesis is primarily used to produce amyloidogenic peptides suitable for high-resolution structural studies. Here, we exploited the shielded environment of protein condensates formed via liquid-liquid phase separation (LLPS) as a protective mechanism against premature aggregation. We designed a fusion protein tag undergoing LLPS in Escherichia coli and linked it to highly amyloidogenic peptides, including β amyloids. We find that the fusion proteins form membraneless organelles during overexpression and remain fluidic-like. We also developed a facile purification method of functional Aβ peptides free of chromatography steps. The strategy exploiting LLPS can be applied to other amyloidogenic, hydrophobic, and repetitive peptides that are otherwise difficult to produce.
Collapse
Affiliation(s)
- Bartosz Gabryelczyk
- Biological and Biomimetic Materials Laboratory (BBML), Center for Sustainable Materials (SusMat), School of Materials Science and Engineering Nanyang Technological University (NTU) Singapore
- Department of Bioproducts and Biosystems, School of Chemical Engineering Aalto University Espoo Finland
| | - Reema Alag
- School of Biological Sciences NTU Singapore
| | | | | | | | - Bhuvaneswari Kannaian
- Biological and Biomimetic Materials Laboratory (BBML), Center for Sustainable Materials (SusMat), School of Materials Science and Engineering Nanyang Technological University (NTU) Singapore
| | - Xiangyan Shi
- Department of Biology Shenzhen MSU‐BIT University Shenzhen China
| | - Markus Linder
- Department of Bioproducts and Biosystems, School of Chemical Engineering Aalto University Espoo Finland
| | | | - Ali Miserez
- Biological and Biomimetic Materials Laboratory (BBML), Center for Sustainable Materials (SusMat), School of Materials Science and Engineering Nanyang Technological University (NTU) Singapore
- School of Biological Sciences NTU Singapore
| |
Collapse
|
3
|
Zhang S, Guaglianone G, Morris MA, Yoo S, Howitz WJ, Xing L, Zheng JG, Jusuf H, Huizar G, Lin J, Kreutzer AG, Nowick JS. Expression of N-Terminal Cysteine Aβ 42 and Conjugation to Generate Fluorescent and Biotinylated Aβ 42. Biochemistry 2021; 60:1191-1200. [PMID: 33793198 DOI: 10.1021/acs.biochem.1c00105] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Fluorescent derivatives of the β-amyloid peptides (Aβ) are valuable tools for studying the interactions of Aβ with cells. Facile access to labeled expressed Aβ offers the promise of Aβ with greater sequence and stereochemical integrity, without impurities from amino acid deletion and epimerization. Here, we report methods for the expression of Aβ42 with an N-terminal cysteine residue, Aβ(C1-42), and its conjugation to generate Aβ42 bearing fluorophores or biotin. The methods rely on the hitherto unrecognized observation that expression of the Aβ(MC1-42) gene yields the Aβ(C1-42) peptide, because the N-terminal methionine is endogenously excised by Escherichia coli. Conjugation of Aβ(C1-42) with maleimide-functionalized fluorophores or biotin affords the N-terminally labeled Aβ42. The expression affords ∼14 mg of N-terminal cysteine Aβ from 1 L of bacterial culture. Subsequent conjugation affords ∼3 mg of labeled Aβ from 1 L of bacterial culture with minimal cost for labeling reagents. High-performance liquid chromatography analysis indicates the N-terminal cysteine Aβ to be >97% pure and labeled Aβ peptides to be 94-97% pure. Biophysical studies show that the labeled Aβ peptides behave like unlabeled Aβ and suggest that labeling of the N-terminus does not substantially alter the properties of the Aβ. We further demonstrate applications of the fluorophore-labeled Aβ peptides by using fluorescence microscopy to visualize their interactions with mammalian cells and bacteria. We anticipate that these methods will provide researchers convenient access to useful N-terminally labeled Aβ, as well as Aβ with an N-terminal cysteine that enables further functionalization.
Collapse
Affiliation(s)
- Sheng Zhang
- Department of Chemistry, University of California-Irvine, Irvine, California 92697-2025, United States
| | - Gretchen Guaglianone
- Department of Chemistry, University of California-Irvine, Irvine, California 92697-2025, United States
| | - Michael A Morris
- Department of Chemistry, University of California-Irvine, Irvine, California 92697-2025, United States
| | - Stan Yoo
- Department of Chemistry, University of California-Irvine, Irvine, California 92697-2025, United States
| | - William J Howitz
- Department of Chemistry, University of California-Irvine, Irvine, California 92697-2025, United States
| | - Li Xing
- Irvine Materials Research Institute (IMRI), University of California-Irvine, Irvine, California 92697-2575, United States
| | - Jian-Guo Zheng
- Irvine Materials Research Institute (IMRI), University of California-Irvine, Irvine, California 92697-2575, United States
| | - Hannah Jusuf
- Department of Chemistry, University of California-Irvine, Irvine, California 92697-2025, United States
| | - Grace Huizar
- Department of Chemistry, University of California-Irvine, Irvine, California 92697-2025, United States
| | - Jonathan Lin
- Department of Chemistry, University of California-Irvine, Irvine, California 92697-2025, United States
| | - Adam G Kreutzer
- Department of Chemistry, University of California-Irvine, Irvine, California 92697-2025, United States
| | - James S Nowick
- Department of Chemistry, University of California-Irvine, Irvine, California 92697-2025, United States.,Department of Pharmaceutical Sciences, University of California-Irvine, Irvine, California 92697-2025, United States
| |
Collapse
|