The Regulator PerR Is Involved in Oxidative Stress Response and Iron Homeostasis and Is Necessary for Full Virulence of Streptococcus pyogenes

Abstract

Ferric uptake regulator (Fur) and Fur-like proteins form an important family of transcriptional regulators in many bacterial species. In this work we have characterized a Fur-like protein, the peroxide regulator PerR, in an M1 serotype of Streptococcus pyogenes. To determine the role of PerR in S. pyogenes, we inactivated the gene by allelic replacement. PerR-deficient bacteria showed 48% reduction of 55 Fe incorporation from the culture medium. Transcriptional analysis revealed that mtsA, encoding a metal-binding protein of an ABC transporter in S. pyogenes, was transcribed at lower levels than were wild-type cells. Although total iron accumulation was reduced, the growth of the mutant strain was not significantly hampered. The mutant showed hyperresistance to hydrogen peroxide, and this response was induced in wild-type cells by growth in aerobiosis, suggesting that PerR acts as an oxidative stress-responsive repressor. PerR may also participate in the response to superoxide stress, as the perR mutant was more sensitive to the superoxide anion and had a reduced transcription of sodA, which encodes the sole superoxide dismutase of S. pyogenes. Complementation of the mutation with a functional perR gene restored 55 Fe incorporation, response to peroxide stress, and transcription of both mtsA and sodA to levels comparable to those of wild-type bacteria. Finally, the perR mutant was attenuated in virulence in a murine air sac model of infection (P < 0.05). These results demonstrate that PerR is involved in the regulation of iron homeostasis and oxidative stress responses and that it contributes to the virulence of S. pyogenes.

Differential Secretomics of Streptococcus pyogenes Reveals a Novel Peroxide Regulator (PerR)-regulated Extracellular Virulence Factor Mitogen Factor3 (MF3)

“…1C). This confirmed that the virulence of the perR deficient mutant was attenuated in the animal model in accordance with previous reports (12)(13)(14). To summarize, these data demonstrated that the perR deficient mutant is useful for discovery of PerR-regulated virulence factors in S. pyogenes.…”

“…After this computational prediction, we hypothesize a novel role for PerR in regulating protein secretion in S. pyogenes. In previous investigations, the PerR regulator was shown to be involved in oxidative stress responses and virulence, and there was no evidence to show that PerR is involved in protein secretion (12)(13)(14). In the present study, we discovered 13 PerR-regulated secreted proteins, which demonstrates that PerR can control the protein secretion directly or indirectly to influence the virulence of S. pyogenes.…”

“…Previous studies have reported that the perR deficient mutant was highly attenuated in virulence in a murine air sac model of infection (12)(13)(14). However, the mechanism by which PerR contributes to S. pyogenes virulence and the specific contribution of PerR-regulated protein expression to bacterial survival at particular host sites during infection remains unknown.…”

“…One factor involved in the S. pyogenes adaptive responses to oxidative stress is the peroxide stress response regulator (PerR) 1 , which is one member of the Fur (ferric uptake repressor) super-family of metal binding transcriptional regulators. Previous studies have also demonstrated that PerR is involved in the regulation of iron homeostasis and oxidative stress responses and that it contributes to the virulence of S. pyogenes (12)(13)(14). Recent research found that although a perR-deficient mutant's capacity to resist peroxide stress did not directly correlate with its ability to cause disease, the appropriate regulation of the peroxide stress response is critical for virulence (13).…”

Analysis of the Transcriptome of Group A Streptococcus in Mouse Soft Tissue Infection

“…By differential gene expression, GAS successfully transitions through three stages of host infection: namely, 1) establishment of infection, 2) adaptation, and 3) dissemination ( Figure 6). Information about stage 1 is based on an expanding body of work, 8,10,11,34,103 and our results support this information by combined early expression of Mga, Ihk/Irr, and FasBCA/X regulatory systems that promote evasion of immune and innate host defenses and enhance host cell contact through surface adhesin production. Down-regulation of the negative regulatory systems of PerR, CovR/S, and CrgR promote production of reactive oxygen species detoxifying enzymes, hyaluronic acid capsule, and antimicrobial peptide resistance mechanisms, respectively, 8,35,[103][104][105][106][107] and our soft tissue model demonstrates similar results.…”