Phenol-Soluble Modulins From Staphylococcus aureus Biofilms Form Complexes With DNA to Drive Autoimmunity

Grando, Kaitlyn; Nicastro, Lauren K.; Tursi, Sarah A.; Anda, Jaime de; Lee, Ernest Y.; Wong, Gerard C. L.; Tükel, Çaǧla

doi:10.3389/fcimb.2022.884065

Cited by 10 publications

(7 citation statements)

References 84 publications

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“…These include e.g. other positively charged polysaccharides, such as Pel in Pseudomonas aeruginosa which also co-localizes with eDNA (45), or polycationic peptides, such as the α-type phenol-soluble modulins which also complexes with eDNA in biofilms (54). We also note a large variation in Z-DNA abundance between different samples (Figure 2), and Z-DNA was primarily present in web-like network of DNA strings while it was largely absent from the eDNA associated with the surface of bacterial cells (Figure 3 and 4).…”

Section: Formation Of Z-dna In Biofilmsmentioning

confidence: 99%

Extracellular G-quadruplex and Z-DNA protect biofilms from DNase I and forms a DNAzyme with peroxidase activity

Minero,

Møllebjerg,

Thiesen

et al. 2023

Preprint

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Many bacteria form biofilms to protect themselves from predators or stressful environmental conditions. In the biofilm, bacteria are embedded in a protective extracellular matrix composed of polysaccharides, proteins and extracellular DNA (eDNA). eDNA most often arises from lysed cells, and it is the only matrix component most biofilms appear to have in common. However, little is known about the form DNA takes in the extracellular space, and how different non-canonical DNA structures such as Z-DNA or G-quadruplex formation might contribute to its function in the biofilm. The aim of this study was to determine if non-canonical DNA structures form in eDNA-rich staphylococcal biofilms, and if these structures protect the biofilm from degradation by nucleases. We grew Staphylococcus epidermidis biofilms in laboratory media amended with hemin and NaCl to stabilize secondary DNA structures and visualized their location by immunolabelling and fluorescence microscopy. We furthermore visualized the macroscopic biofilm structure by optical coherence tomography. We developed assays to quantify degradation of Z-DNA and G-quadruplex DNA oligos by different nucleases, and subsequently investigated how these enzymes affected eDNA in the biofilms. Z-DNA and G-quadruplex DNA were abundant in the biofilm matrix, and were often present in a web-like structure in biofilms grown in vitro and in vivo using a murine implant-associated osteomyelitis model. In vitro, the structures did not form in the absence of NaCl or mechanical shaking during biofilm growth, or in bacterial strains deficient in eDNA or exopolysaccharide production. We thus infer that eDNA and polysaccharides interact, leading to non-canonical DNA structures under mechanical stress when stabilized by salt, and we confirmed that G-quadruplex DNA and Z-DNA was also present in biofilms from infected implants. Mammalian DNase I lacked activity against Z-DNA and G-quadruplex DNA, while Micrococcal nuclease could degrade G-quadruplex DNA and S1 Aspergillus nuclease could degrade Z-DNA. Micrococcal nuclease, which originates from Staphylococcus aureus, may thus be key for dispersal of biofilm in staphylococci. In addition to its structural role, we show for the first time that the eDNA in biofilms forms a DNAzyme with peroxidase-like activity in the presence of hemin. While peroxidases are part of host defenses against pathogens, we now show that biofilms can possess intrinsic peroxidase activity in the extracellular matrix.

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Section: Formation Of Z-dna In Biofilmsmentioning

confidence: 99%

Extracellular G-quadruplex and Z-DNA protect biofilms from DNase I and forms a DNAzyme with peroxidase activity

Minero,

Møllebjerg,

Thiesen

et al. 2023

Preprint

View full text Add to dashboard Cite

show abstract

“…These include e.g. other positively charged polysaccharides, such as Pel in Pseudomonas aeruginosa which also co-localizes with eDNA ( 54 ), or polycationic peptides, such as the α-type phenol-soluble modulins which also complexes with eDNA in biofilms ( 66 ). It is thus possible that PNAG and other polycationic matrix components contribute to Z-DNA formation in biofilms, but even if they do promote Z-DNA formation, they cannot accomplish this feat alone.…”

Section: Discussionmentioning

confidence: 99%

Extracellular G-quadruplexes and Z-DNA protect biofilms from DNase I, and G-quadruplexes form a DNAzyme with peroxidase activity

Minero,

Møllebjerg,

Thiesen

et al. 2024

Nucleic Acids Research

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Many bacteria form biofilms to protect themselves from predators or stressful environmental conditions. In the biofilm, bacteria are embedded in a protective extracellular matrix composed of polysaccharides, proteins and extracellular DNA (eDNA). eDNA most often is released from lysed bacteria or host mammalian cells, and it is the only matrix component most biofilms appear to have in common. However, little is known about the form DNA takes in the extracellular space, and how different non-canonical DNA structures such as Z-DNA or G-quadruplexes might contribute to its function in the biofilm. The aim of this study was to determine if non-canonical DNA structures form in eDNA-rich staphylococcal biofilms, and if these structures protect the biofilm from degradation by nucleases. We grew Staphylococcus epidermidis biofilms in laboratory media supplemented with hemin and NaCl to stabilize secondary DNA structures and visualized their location by immunolabelling and fluorescence microscopy. We furthermore visualized the macroscopic biofilm structure by optical coherence tomography. We developed assays to quantify degradation of Z-DNA and G-quadruplex DNA oligos by different nucleases, and subsequently investigated how these enzymes affected eDNA in the biofilms. Z-DNA and G-quadruplex DNA were abundant in the biofilm matrix, and were often present in a web-like structures. In vitro, the structures did not form in the absence of NaCl or mechanical shaking during biofilm growth, or in bacterial strains deficient in eDNA or exopolysaccharide production. We thus infer that eDNA and polysaccharides interact, leading to non-canonical DNA structures under mechanical stress when stabilized by salt. We also confirmed that G-quadruplex DNA and Z-DNA was present in biofilms from infected implants in a murine implant-associated osteomyelitis model. Mammalian DNase I lacked activity against Z-DNA and G-quadruplex DNA, while Micrococcal nuclease could degrade G-quadruplex DNA and S1 Aspergillus nuclease could degrade Z-DNA. Micrococcal nuclease, which originates from Staphylococcus aureus, may thus be key for dispersal of biofilm in staphylococci. In addition to its structural role, we show for the first time that the eDNA in biofilms forms a DNAzyme with peroxidase-like activity in the presence of hemin. While peroxidases are part of host defenses against pathogens, we now show that biofilms can possess intrinsic peroxidase activity in the extracellular matrix.

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“… 23 , 29 , 47–49 Recent work suggests that chronic systemic exposure to biofilms or to the amyloid/DNA complexes from Gram-negative or Gram-positive bacteria, curli/DNA and PSM/DNA, respectively, are associated with the generation of autoimmune responses both in mice and humans. 22 , 23 , 25 , 31 , 37 , 49 , 50 Curli is produced in the gastrointestinal tract by Gram-negative enteric bacteria 37 and serves as a major biofilm-associated PAMP. 9 , 13 , 19 , 21 , 24 , 51 During invasive S .…”

Section: Discussionmentioning

confidence: 99%

Systemic exposure to bacterial amyloid curli alters the gut mucosal immune response and the microbiome, exacerbating Salmonella -induced arthritis

Bessho,

Grando,

Kyrylchuk

et al. 2023

Gut Microbes

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The Salmonella biofilm-associated amyloid protein, curli, is a dominant instigator of systemic inflammation and autoimmune responses following Salmonella infection. Systemic curli injections or infection of mice with Salmonella Typhimurium induce the major features of reactive arthritis, an autoimmune disorder associated with Salmonella infection in humans. In this study, we investigated the link between inflammation and microbiota in exacerbating autoimmunity. We studied C57BL/6 mice from two sources, Taconic Farms and Jackson Labs. Mice from Taconic Farms have been reported to have higher basal levels of the inflammatory cytokine IL − 17 than do mice from Jackson Labs due to the differences in their microbiota. When we systemically injected mice with purified curli, we observed a significant increase in diversity in the microbiota of Jackson Labs mice but not in that of the Taconic mice. In Jackson Labs, mice, the most striking effect was the expansion of Prevotellaceae . Furthermore, there were increases in the relative abundance of the family Akkermansiaceae and decreases in families Clostridiaceae and Muribaculaceae in Jackson Labs mice. Curli treatment led to significantly aggravated immune responses in the Taconic mice compared to Jackson Labs counterparts. Expression and production of IL − 1β, a cytokine known to promote IL − 17 production, as well as expression of Tnfa increased in the gut mucosa of Taconic mice in the first 24 hours after curli injections, which correlated with significant increases in the number of neutrophils and macrophages in the mesenteric lymph nodes. A significant increase in the expression of Ccl3 in colon and cecum of Taconic mice injected with curli was detected. Taconic mice injected with curli also had elevated levels of inflammation in their knees. Overall, our data suggest that autoimmune responses to bacterial ligands, such as curli, are amplified in individuals with a microbiome that promote inflammation.

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Phenol-Soluble Modulins From Staphylococcus aureus Biofilms Form Complexes With DNA to Drive Autoimmunity

Cited by 10 publications

References 84 publications

Extracellular G-quadruplex and Z-DNA protect biofilms from DNase I and forms a DNAzyme with peroxidase activity

Extracellular G-quadruplex and Z-DNA protect biofilms from DNase I and forms a DNAzyme with peroxidase activity

Extracellular G-quadruplexes and Z-DNA protect biofilms from DNase I, and G-quadruplexes form a DNAzyme with peroxidase activity

Systemic exposure to bacterial amyloid curli alters the gut mucosal immune response and the microbiome, exacerbating Salmonella -induced arthritis

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