Functional Amyloids in Bacteria

Dueholm, Morten Simonsen; Nielsen, Per Halkjær; Chapman, Matthew R.; Otzen, Daniel E.

doi:10.1002/9783527654185.ch19

Cited by 10 publications

(12 citation statements)

References 92 publications

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“…The prokaryotic functional amyloid (Epstein and Chapman, 2008 ; Dueholm et al, 2013 ), affords diverse functions in biofilm communities that range from structural components namely, fimbriae, curli and other cellular appendages to act as oligomeric toxins (Larsen et al, 2007 ; Dueholm et al, 2013 ); reservoirs for quorum sensing; signaling molecules and binding of redox mediators (Dueholm and Nielsen, 2017 ). Furthermore, there is potential for these prokaryotic Aβ-like fibers to cross the blood-brain barrier (BBB) and form pathological senile plaques seen in AD.…”

Section: Functional Amyloids From Prokaryotic Originsmentioning

confidence: 99%

“…The molecular mimicry theory incorporates microbial curli fibers and human Aβ as a protein-protein interaction, which can result in cross-seeding even if these proteins are dissimilar (Friedland, 2015 ). Additional prokaryotic and yeast functional amyloid systems and their sources are listed in Table 1 (Bian et al, 2000 ; Gophna et al, 2001 ; Larsen et al, 2007 , 2008 ; Dueholm et al, 2010 , 2012 , 2013 ; Dueholm and Nielsen, 2017 ).…”

Section: Functional Amyloids From Prokaryotic Originsmentioning

confidence: 99%

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Periodontitis, Microbiomes and their Role in Alzheimer’s Disease

Pritchard

Crean

Olsen

et al. 2017

Front. Aging Neurosci.

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As far back as the eighteenth and early nineteenth centuries, microbial infections were responsible for vast numbers of deaths. The trend reversed with the introduction of antibiotics coinciding with longer life. Increased life expectancy however, accompanied the emergence of age related chronic inflammatory states including the sporadic form of Alzheimer’s disease (AD). Taken together, the true challenge of retaining health into later years of life now appears to lie in delaying and/or preventing the progression of chronic inflammatory diseases, through identifying and influencing modifiable risk factors. Diverse pathogens, including periodontal bacteria have been associated with AD brains. Amyloid-beta (Aβ) hallmark protein of AD may be a consequence of infection, called upon due to its antimicrobial properties. Up to this moment in time, a lack of understanding and knowledge of a microbiome associated with AD brain has ensured that the role pathogens may play in this neurodegenerative disease remains unresolved. The oral microbiome embraces a range of diverse bacterial phylotypes, which especially in vulnerable individuals, will excite and perpetuate a range of inflammatory conditions, to a wide range of extra-oral body tissues and organs specific to their developing pathophysiology, including the brain. This offers the tantalizing opportunity that by controlling the oral-specific microbiome; clinicians may treat or prevent a range of chronic inflammatory diseases orally. Evolution has equipped the human host to combat infection/disease by providing an immune system, but Porphyromonas gingivalis and selective spirochetes, have developed immune avoidance strategies threatening the host-microbe homeostasis. It is clear from longitudinal monitoring of patients that chronic periodontitis contributes to declining cognition. The aim here is to discuss the contribution from opportunistic pathogens of the periodontal microbiome, and highlight the challenges, the host faces, when dealing with unresolvable oral infections that may lead to clinical manifestations that are characteristic for AD.

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Section: Functional Amyloids From Prokaryotic Originsmentioning

confidence: 99%

Section: Functional Amyloids From Prokaryotic Originsmentioning

confidence: 99%

Periodontitis, Microbiomes and their Role in Alzheimer’s Disease

Pritchard

Crean

Olsen

et al. 2017

Front. Aging Neurosci.

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“…While in humans the concept of amyloid has been traditionally interpreted in terms of lethality, observations from various evolutionary distinct organisms strongly support a role that extends well beyond toxicity. In prokaryotes, cell-surface amyloid polymerization is quite diffuse (Dueholm et al, 2013 ), and the biogenesis of curli filaments from enterobacteria is an example of how unicellular organisms use amyloidogenesis for physiological processes such as biofilm formation, host adhesion, and cellular clustering. CsgA protein, the principal component of curli in E. coli , polymerizes into amyloids after the secretion across the outer membrane.…”

Section: Amyloid Functionmentioning

confidence: 99%

Legal but lethal: functional protein aggregation at the verge of toxicity

Falsone

2015

Front. Cell. Neurosci.

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Many neurodegenerative disorders are linked to irreversible protein aggregation, a process that usually comes along with toxicity and serious cellular damage. However, it is emerging that protein aggregation can also serve for physiological purposes, as impressively shown for prions. While the aggregation of this protein family was initially considered exclusively toxic in mammalians organisms, it is now almost clear that many other proteins adopt prion-like attributes to rationally polymerize into higher order complexes with organized physiologic roles. This implies that cells can tolerate at least in some measure the accumulation of inherently dangerous protein aggregates for functional profit. This review summarizes currently known strategies that living organisms adopt to preserve beneficial aggregation, and to prevent the catastrophic accumulation of toxic aggregates that frequently accompany neurodegeneration.

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“…Sequence analysis suggests that FapF is a β-barrel membrane protein and FapD a peptidase (Dueholm et al, 2013a ). While such amyloid structures are typically associated with neurodegenerative diseases such as Alzheimer's and Parkinson's (Otzen, 2012 ), it is increasingly clear that they also have a vital and beneficial role to play in bacteria in general (Chapman et al, 2002 ; Dueholm et al, 2012 ). Amyloid is found widespread in the bacterial kingdom (Larsen et al, 2007 , 2008 ) and we have very recently reported their existence in Archaea (Dueholm et al, 2015 ).…”

Section: Introductionmentioning

confidence: 99%

Functional bacterial amyloid increases Pseudomonas biofilm hydrophobicity and stiffness

et al. 2015

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The success of Pseudomonas species as opportunistic pathogens derives in great part from their ability to form stable biofilms that offer protection against chemical and mechanical attack. The extracellular matrix of biofilms contains numerous biomolecules, and it has recently been discovered that in Pseudomonas one of the components includes β-sheet rich amyloid fibrils (functional amyloid) produced by the fap operon. However, the role of the functional amyloid within the biofilm has not yet been investigated in detail. Here we investigate how the fap-based amyloid produced by Pseudomonas affects biofilm hydrophobicity and mechanical properties. Using atomic force microscopy imaging and force spectroscopy, we show that the amyloid renders individual cells more resistant to drying and alters their interactions with hydrophobic probes. Importantly, amyloid makes Pseudomonas more hydrophobic and increases biofilm stiffness 20-fold. Deletion of any one of the individual members of in the fap operon (except the putative chaperone FapA) abolishes this ability to increase biofilm stiffness and correlates with the loss of amyloid. We conclude that amyloid makes major contributions to biofilm mechanical robustness.

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Functional Amyloids in Bacteria

Cited by 10 publications

References 92 publications

Periodontitis, Microbiomes and their Role in Alzheimer’s Disease

Periodontitis, Microbiomes and their Role in Alzheimer’s Disease

Legal but lethal: functional protein aggregation at the verge of toxicity

Functional bacterial amyloid increases Pseudomonas biofilm hydrophobicity and stiffness

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