scholarly journals Protease Resistance of ex vivo Amyloid Fibrils implies the proteolytic Selection of disease-associated Fibril Morphologies

2021 ◽  
Author(s):  
Jonathan Schoenfelder ◽  
Peter Benedikt Pfeiffer ◽  
Tejaswini Pradhan ◽  
Johan Bijzet ◽  
Bouke P.C. Hazenberg ◽  
...  
Keyword(s):  
Amyloid Fibrils ◽  
Ex Vivo ◽  
Amino Acid Sequences ◽  
The Body ◽  
Amyloid A ◽  
Chain Analysis ◽  
Polypeptide Chains ◽  
Amyloid Diseases ◽  
Selection Of

Several studies recently showed that ex vivo fibrils from patient or animal tissue were structurally different from in vitro formed fibrils from the same polypeptide chain. Analysis of serum amyloid A (SAA) and Aβ-derived amyloid fibrils additionally revealed that ex vivo fibrils were more protease stable than in vitro fibrils. These observations gave rise to the proteolytic selection hypothesis that suggested that disease-associated amyloid fibrils were selected inside the body by their ability to resist endogenous clearance mechanisms. We here show, for more than twenty different fibril samples, that ex vivo fibrils are more protease stable than in vitro fibrils. These data support the idea of a proteolytic selection of pathogenic amyloid fibril morphologies and help to explain why only few amino acid sequences lead to amyloid diseases, although many, if not all, polypeptide chains can form amyloid fibrils in vitro.

Methods to study the structure of misfolded protein states in systemic amyloidosis

2021 ◽  
Vol 49 (2) ◽  
pp. 977-985
Author(s):  
Marcus Fändrich ◽  
Matthias Schmidt
Keyword(s):  
Protein Misfolding ◽  
Amyloid Fibrils ◽  
Ex Vivo ◽  
Systemic Amyloidosis ◽  
Structural Basis ◽  
Amyloid A ◽  
Serum Amyloid A Protein ◽  
Proteolytic Stability

Systemic amyloidosis is defined as a protein misfolding disease in which the amyloid is not necessarily deposited within the same organ that produces the fibril precursor protein. There are different types of systemic amyloidosis, depending on the protein constructing the fibrils. This review will focus on recent advances made in the understanding of the structural basis of three major forms of systemic amyloidosis: systemic AA, AL and ATTR amyloidosis. The three diseases arise from the misfolding of serum amyloid A protein, immunoglobulin light chains or transthyretin. The presented advances in understanding were enabled by recent progress in the methodology available to study amyloid structures and protein misfolding, in particular concerning cryo-electron microscopy (cryo-EM) and nuclear magnetic resonance (NMR) spectroscopy. An important observation made with these techniques is that the structures of previously described in vitro formed amyloid fibrils did not correlate with the structures of amyloid fibrils extracted from diseased tissue, and that in vitro fibrils were typically more protease sensitive. It is thus possible that ex vivo fibrils were selected in vivo by their proteolytic stability.

scholarly journals Cryo-EM demonstrates the in vitro proliferation of an ex vivo amyloid fibril morphology by seeding

2022 ◽  
Vol 13 (1) ◽  
Author(s):  
Thomas Heerde ◽  
Matthies Rennegarbe ◽  
Alexander Biedermann ◽  
Dilan Savran ◽  
Peter B. Pfeiffer ◽  
...  
Keyword(s):  
Amyloid Fibrils ◽  
Ex Vivo ◽  
Proteinase K ◽  
Seed Structure ◽  
In Vitro Proliferation ◽  
Amyloid A ◽  
Fibril Structure ◽  
Proteolytic Stability ◽  
Fibril Morphology

AbstractSeveral studies showed that seeding of solutions of monomeric fibril proteins with ex vivo amyloid fibrils accelerated the kinetics of fibril formation in vitro but did not necessarily replicate the seed structure. In this research we use cryo-electron microscopy and other methods to analyze the ability of serum amyloid A (SAA)1.1-derived amyloid fibrils, purified from systemic AA amyloidosis tissue, to seed solutions of recombinant SAA1.1 protein. We show that 98% of the seeded fibrils remodel the full fibril structure of the main ex vivo fibril morphology, which we used for seeding, while they are notably different from unseeded in vitro fibrils. The seeded fibrils show a similar proteinase K resistance as ex vivo fibrils and are substantially more stable to proteolytic digestion than unseeded in vitro fibrils. Our data support the view that the fibril morphology contributes to determining proteolytic stability and that pathogenic amyloid fibrils arise from proteolytic selection.

scholarly journals Amyloid seeding of transthyretin by ex vivo cardiac fibrils and its inhibition

2018 ◽  
Vol 115 (29) ◽  
pp. E6741-E6750 ◽  
Author(s):  
Lorena Saelices ◽  
Kevin Chung ◽  
Ji H. Lee ◽  
Whitaker Cohn ◽  
Julian P. Whitelegge ◽  
...  
Keyword(s):  
Amyloid Fibrils ◽  
Ex Vivo ◽  
Standard Of Care ◽  
Wild Type ◽  
Current Standard ◽  
Transthyretin Amyloidosis ◽  
Physiological Conditions ◽  
Type Gene ◽  
Amyloid Diseases

Each of the 30 human amyloid diseases is associated with the aggregation of a particular precursor protein into amyloid fibrils. In transthyretin amyloidosis (ATTR), mutant or wild-type forms of the serum carrier protein transthyretin (TTR), synthesized and secreted by the liver, convert to amyloid fibrils deposited in the heart and other organs. The current standard of care for hereditary ATTR is liver transplantation, which replaces the mutantTTRgene with the wild-type gene. However, the procedure is often followed by cardiac deposition of wild-type TTR secreted by the new liver. Here we find that amyloid fibrils extracted from autopsied and explanted hearts of ATTR patients robustly seed wild-type TTR into amyloid fibrils in vitro. Cardiac-derived ATTR seeds can accelerate fibril formation of wild-type and monomeric TTR at acidic pH and under physiological conditions, respectively. We show that this seeding is inhibited by peptides designed to complement structures of TTR fibrils. These inhibitors cap fibril growth, suggesting an approach for halting progression of ATTR.

scholarly journals AA amyloid fibrils from diseased tissue are structurally different from in vitro formed SAA fibrils

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Akanksha Bansal ◽  
Matthias Schmidt ◽  
Matthies Rennegarbe ◽  
Christian Haupt ◽  
Falk Liberta ◽  
...  
Keyword(s):  
Protein Misfolding ◽  
Serum Amyloid A ◽  
Amyloid Fibrils ◽  
Ex Vivo ◽  
Surrounding Tissue ◽  
Amyloid A ◽  
Cryo Electron Microscopy ◽  
Β Sheet ◽  
Misfolding Disease

AbstractSystemic AA amyloidosis is a world-wide occurring protein misfolding disease of humans and animals. It arises from the formation of amyloid fibrils from serum amyloid A (SAA) protein. Using cryo electron microscopy we here show that amyloid fibrils which were purified from AA amyloidotic mice are structurally different from fibrils formed from recombinant SAA protein in vitro. Ex vivo amyloid fibrils consist of fibril proteins that contain more residues within their ordered parts and possess a higher β-sheet content than in vitro fibril proteins. They are also more resistant to proteolysis than their in vitro formed counterparts. These data suggest that pathogenic amyloid fibrils may originate from proteolytic selection, allowing specific fibril morphologies to proliferate and to cause damage to the surrounding tissue.

The Role of Polyphenols in the Modulation of Plasma Non-Enzymatic Antioxidant Capacity (NEAC)

2012 ◽  
Vol 82 (3) ◽  
pp. 228-232 ◽  
Author(s):  
Mauro Serafini ◽  
Giuseppa Morabito
Keyword(s):  
Antioxidant Capacity ◽  
Dietary Intervention ◽  
Ex Vivo ◽  
The Body ◽  
Dietary Polyphenols ◽  
Enzymatic Antioxidant ◽  
Endogenous Antioxidant

Dietary polyphenols have been shown to scavenge free radicals, modulating cellular redox transcription factors in different in vitro and ex vivo models. Dietary intervention studies have shown that consumption of plant foods modulates plasma Non-Enzymatic Antioxidant Capacity (NEAC), a biomarker of the endogenous antioxidant network, in human subjects. However, the identification of the molecules responsible for this effect are yet to be obtained and evidences of an antioxidant in vivo action of polyphenols are conflicting. There is a clear discrepancy between polyphenols (PP) concentration in body fluids and the extent of increase of plasma NEAC. The low degree of absorption and the extensive metabolism of PP within the body have raised questions about their contribution to the endogenous antioxidant network. This work will discuss the role of polyphenols from galenic preparation, food extracts, and selected dietary sources as modulators of plasma NEAC in humans.

Protease resistance of ex vivo amyloid fibrils implies the proteolytic selection of disease-associated fibril morphologies

Amyloid ◽  
2021 ◽  
pp. 1-9
Author(s):  
Jonathan Schönfelder ◽  
Peter Benedikt Pfeiffer ◽  
Tejaswini Pradhan ◽  
Johan Bijzet ◽  
Bouke P. C. Hazenberg ◽  
...  
Keyword(s):  
Amyloid Fibrils ◽  
Ex Vivo ◽  
Protease Resistance ◽  
Selection Of

scholarly journals Extracellular vesicles engineered with valency-controlled DNA nanostructures deliver CRISPR/Cas9 system for gene therapy

2020 ◽  
Vol 48 (16) ◽  
pp. 8870-8882 ◽  
Author(s):  
Jialang Zhuang ◽  
Jizhou Tan ◽  
Chenglin Wu ◽  
Jie Zhang ◽  
Ting Liu ◽  
...  
Keyword(s):  
Extracellular Vesicles ◽  
Ex Vivo ◽  
Primary Liver Cancer ◽  
The Body ◽  
Dna Aptamer ◽  
Great Promise ◽  
Tumor Growth Inhibition ◽  
Specific Cell ◽  
Dna Nanostructures

Abstract Extracellular vesicles (EVs) hold great promise for transporting CRISPR–Cas9 RNA-guided endonucleases (RNP) throughout the body. However, the cell-selective delivery of EVs is still a challenge. Here, we designed valency-controlled tetrahedral DNA nanostructures (TDNs) conjugated with DNA aptamer, and loaded the valency-controlled TDNs on EV surface via cholesterol anchoring for specific cell targeting. The targeting efficacy of different ratios of aptamer/cholesterol from 1:3 to 3:1 in TDNs on decorating EVs was investigated. TDNs with one aptamer and three cholesterol anchors (TDN1) efficiently facilitated the tumor-specific accumulation of the EVs in cultured HepG2 cells and human primary liver cancer-derived organoids, as well as xenograft tumor models. The intracellular delivery of RNP by TDN1-EVs successfully realized its subsequent genome editing, leading to the downregulation of GFP or WNT10B in specific cells. This system was ultimately applied to reduce the protein expression of WNT10B, which presented remarkable tumor growth inhibition in vitro, ex vivo and in vivo, and could be extended to other therapeutic targets. The present study provides a platform for the directional display of aptamer on surface labeling and the EVs-based Cas9 delivery, which provides a meaningful idea for future cell-selective gene editing.

scholarly journals Ex Vivo and In Vitro Effect of Serum Amyloid A in the Induction of Macrophage M2 Markers and Efferocytosis of Apoptotic Neutrophils

2015 ◽  
Vol 194 (10) ◽  
pp. 4891-4900 ◽  
Author(s):  
Lei Sun ◽  
Huibin Zhou ◽  
Ziyan Zhu ◽  
Qian Yan ◽  
Lili Wang ◽  
...  
Keyword(s):  
Serum Amyloid A ◽  
Ex Vivo ◽  
Serum Amyloid ◽  
Amyloid A ◽  
Vitro Effect

scholarly journals Platelet generation from circulating megakaryocytes is triggered in the lung vasculature

2021 ◽  
Author(s):  
Xiaojuan Zhao ◽  
Dominic Alibhai ◽  
Tony G. Walsh ◽  
Nathalie Tarassova ◽  
Semra Z. Birol ◽  
...  
Keyword(s):  
Blood Cells ◽  
Ex Vivo ◽  
Critical Role ◽  
The Body ◽  
Mouse Lung ◽  
Generation Process ◽  
Large Size ◽  
Large Numbers ◽  
Microfluidic Chamber

Platelets, small hemostatic blood cells, are derived from megakaryocytes, although the generation process is not clear. Only small numbers of platelets have been produced in systems outside the body, where bone marrow and lung are proposed as sites of platelet generation. Here we show that perfusion of megakaryocytes ex vivo through the mouse lung vasculature generates very large numbers of platelets, up to 3,000 per megakaryocyte. Despite their large size, megakaryocytes were able repeatedly to passage through the lung vasculature, leading to enucleation and fragmentation to generate platelets intravascularly. Using the ex vivo lung and a novel in vitro microfluidic chamber we determined the contributions of oxygenation, ventilation and endothelial cell health to platelet generation, and showed a critical role for the actin regulator TPM4.

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