Dataset Information

Cross-linked amyloidogenic proteins as potential aggregation inhibitors

ABSTRACT: Amyloidogenic proteins, characterized by their ability to form fibrillar aggregates with β sheet structure play an important role in several degenerative diseases, including Parkinson’s disease. Numerous amyloidogenic proteins, such as α synuclein, are intrinsically disordered (or contain ID regions, hence they also present as highly dynamic conformational ensembles in these regions. Aggregation is an inherent property of the polypeptide chains and under non physiological, appropriate conditions most of the proteins can aggregate and form polymers of various structures. Since amyloid fib ril s and oligomers are associated with a great variety of human diseases, inhibition of protein aggregation has great importance and it can be addressed by using small molecules, peptides or proteins. Our research aim was to study the potential application of modified forms of different amyloidogenic proteins as inhibitor molecules by introducing structural constraints in them. Under various conditions, different amyloidogenic proteins’ (α-synuclein and β2-microglobulin) monomer molecules have been cross linked intramolecularly and the heterogeneous mixtures has been fractionated by HPLC. The inhibitory potential of the isolated and effective molecules has been experimentally investigated by various methods ThT assay, TEM, CD spectroscopy). Furthermore, the locations of the crosslinks in the molecules were determined by mass spectrometry, and their structures are modeled in silico. Our results revealed that conformational constrains applied by cross linking on amyloidogenic proteins block their amyloid formation. Moreover, these molecules exhibited inhibitory effect on the aggregation of the unmodified proteins, as well.

INSTRUMENT(S): SELECT SERIES Cyclic IMS

ORGANISM(S): Homo Sapiens (human) Escherichia Coli

DISEASE(S): Parkinson's Disease

SUBMITTER: Gabriella Gellen

LAB HEAD: Dr. Gitta Schlosser

PROVIDER: PXD042501 | Pride | 2023-10-24

REPOSITORIES: Pride

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Publications

Cross-Linked α-Synuclein as Inhibitor of Amyloid Formation.

Murvai Nikoletta N Gellen Gabriella G Micsonai András A Schlosser Gitta G Kardos József J

International journal of molecular sciences 20230829 17

The aggregation and amyloid formation of α-synuclein is associated with Parkinson's disease and other synucleinopathies. In its native, monomeric form α-synuclein is an intrinsically disordered protein represented by highly dynamic conformational ensembles. Inhibition of α-synuclein aggregation using small molecules, peptides, or proteins has been at the center of interest in recent years. Our aim was to explore the effects of cross-linking on the structure and aggregation/amyloid formation prop ...[more]

PMID: 37686208

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Project description:INTRODUCTION: The pathogenicity at differing points along the aggregation pathway of many fibril-forming proteins associated with neurodegenerative diseases is unclear. Understanding the effect of different aggregation states of these proteins on cellular processes is essential to enhance understanding of diseases and provide future options for diagnosis and therapeutic intervention.</br>OBJECTIVES:To establish a robust method to probe the metabolic changes of neuronal cells and use it to monitor cellular response to challenge with three amyloidogenic proteins associated with neurodegenerative diseases in different aggregation states.</br>METHOD: Neuroblastoma SH-SY5Y cells were employed to design a robust routine system to perform a statistically rigorous NMR metabolomics study into cellular effects of sub-toxic levels of alpha-synuclein, amyloid-beta 40 and amyloid-beta 42 in monomeric, oligomeric and fibrillar conformations.</br>RESULTS: This investigation developed a rigorous model to monitor intracellular metabolic profiles of neuronal cells through combination of existing methods. This model revealed eight key metabolites that are altered when neuroblastoma cells are challenged with proteins in different aggregation states. Metabolic pathways associated with lipid metabolism, neurotransmission and adaptation to oxidative stress and inflammation are the predominant contributors to the cellular variance and intracellular metabolite levels. The observed metabolite changes for monomer and oligomer challenge may represent cellular effort to counteract the pathogenicity of the challenge, whereas fibrillar challenge is indicative of system shutdown. This implies that although markers of stress are more prevalent under oligomeric challenge the fibrillar response suggests a more toxic environment.</br>CONCLUSION: This approach is applicable to any cell type that can be cultured in a laboratory (primary or cell line) as a method of investigating how protein challenge affects signalling pathways, providing additional understanding as to the role of protein aggregation in neurodegenerative disease initiation and progression.

Project description:Abnormal accumulation of aggregated proteins and sustained microglial activation are important contributors of neurodegenerative process in neurological diseases. Recent studies have shown that aggregation-prone proteins, such as a-synuclein, the protein implicated in Parkinson’s disease (PD), are released from neuronal cells and thus present in the extracellular fluid, pointing to the possible paracrine effects of these proteins on microglial immune responses. However, the mechanism underlying the disease-associated microglial activation and the role of neuronal proteins in this process remain unknown. Here, we show that extracellular a-synuclein released from neuronal cells is an endogenous ligand of toll-like receptor 2 (TLR2) and activates microglia, which in turn induces neurodegeneration. Interaction between neuron-released a-synuclein and TLR2 and subsequent activation of the TLR2 signaling were demonstrated comprehensively by using computational modeling of signaling network and by the experimental validation in TLR2-deficient microglia both in vitro and in vivo. In contrast to the neuron-released a-synuclein, recombinant a-synuclein proteins, including monomer, oligomer, fibril, or nitrated forms, were not able to interact or activate TLR2, suggesting that neuronal cells have a mechanism of enriching specific forms of a-synuclein capable of activating TLR2 during the process of releasing this protein. Taken together, the results suggest that both neuron-released extracellular a-synuclein and TLR2 might be novel therapeutic targets for modifying neuroinflammation in PD and related neurodegenerative diseases. We collected culture media from differentiated SH-SY5Y cells overexpressing either human a-synuclein (alpha-SCM) or beta-galactosidase (LZCM) and treat these media to primary rat microglia at the concentration of a-synuclein of 1.1M. Transcriptome analyses with microglial cells treated with either aSCM or LZCM at two different time points, 6 h and 24 h.

Dataset Information

Cross-linked amyloidogenic proteins as potential aggregation inhibitors

Publications

Cross-Linked α-Synuclein as Inhibitor of Amyloid Formation.

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