scholarly journals A Strain-Specific Catalase Mutation and Mutation of the Metal-Binding Transporter Gene mntC Attenuate Neisseria gonorrhoeae In Vivo but Not by Increasing Susceptibility to Oxidative Killing by Phagocytes

2008 ◽  
Vol 77 (3) ◽  
pp. 1091-1102 ◽  
Author(s):  
Hong Wu ◽  
Ángel A. Soler-García ◽  
Ann E. Jerse

ABSTRACT The hallmark of gonorrhea is an intense inflammatory response that is characterized by polymorphonuclear leukocytes (PMNs) with intracellular gonococci. A redundancy of defenses may protect Neisseria gonorrhoeae from phagocyte-derived reactive oxygen species. Here we showed that a gonococcal catalase (kat) mutant in strain MS11 was more sensitive to H2O2 than mutants in cytochrome c peroxidase (ccp), methionine sulfoxide reductase (msrA), or the metal-binding protein (mntC) of the MntABC transporter. kat ccp and kat ccp mntC mutants were significantly more sensitive to H2O2 than mutants in any single factor. None of the mutants showed increased susceptibility to murine PMNs. Recovery of the mntC and kat ccp mntC mutants from the lower genital tract of BALB/c mice, but not the kat or kat ccp mutants, was significantly reduced relative to wild-type bacteria. Interestingly, unlike the MS11 kat mutant, a kat mutant of strain FA1090 was attenuated during competitive infection with wild-type FA1090 bacteria. The FA1090 kat mutant and MS11 mntC mutant were also attenuated in mice that are unable to generate a phagocytic respiratory burst. We conclude that inactivation of three well-characterized antioxidant genes (kat, ccp, and mntC) does not increase gonococcal susceptibility to the phagocytic respiratory burst during infection and that gonococcal catalase and the MntC protein confer an unidentified advantage in vivo. In the case of catalase, this advantage is strain specific. Finally, we also showed that an msrA mutant of strain MS11 demonstrated delayed attenuation in BALB/c but not C57BL/6 mice. Therefore, MsrA/B also appears to play a role in infection that is dependent on host genetic background.

2006 ◽  
Vol 281 (43) ◽  
pp. 32668-32675 ◽  
Author(s):  
Nathan Brot ◽  
Jean-François Collet ◽  
Lynnette C. Johnson ◽  
Thomas J. Jönsson ◽  
Herbert Weissbach ◽  
...  

The PilB protein from Neisseria gonorrhoeae is located in the periplasm and made up of three domains. The N-terminal, thioredoxin-like domain (NT domain) is fused to tandem methionine sulfoxide reductase A and B domains (MsrA/B). We show that the α domain of Escherichia coli DsbD is able to reduce the oxidized NT domain, which suggests that DsbD in Neisseria can transfer electrons from the cytoplasmic thioredoxin to the periplasm for the reduction of the MsrA/B domains. An analysis of the available complete genomes provides further evidence for this proposition in other bacteria where DsbD/CcdA, Trx, MsrA, and MsrB gene homologs are all located in a gene cluster with a common transcriptional direction. An examination of wild-type PilB and a panel of Cys to Ser mutants of the full-length protein and the individually expressed domains have also shown that the NT domain more efficiently reduces the MsrA/B domains when in the polyprotein context. Within this frame-work there does not appear to be a preference for the NT domain to reduce the proximal MsrA domain over MsrB domain. Finally, we report the 1.6Å crystal structure of the NT domain. This structure confirms the presence of a surface loop that makes it different from other membrane-tethered, Trx-like molecules, including TlpA, CcmG, and ResA. Subtle differences are observed in this loop when compared with the Neisseria meningitidis NT domain structure. The data taken together supports the formation of specific NT domain interactions with the MsrA/B domains and its in vivo recycling partner, DsbD.


2019 ◽  
Vol 3 (Supplement_1) ◽  
pp. S106-S107
Author(s):  
Kevin Thyne ◽  
Yuhong Liu ◽  
Adam B Salmon

Abstract While caloric restriction (CR) provides highly robust improvements to longevity and health, dietary restriction of the essential amino acid methionine can provide similar benefits including improved metabolic function and increased longevity. Despite these similarities between CR and methionine restriction (MR), there is growing evidence to suggest they may be mediated by different mechanisms that require further elucidation. The sulfur side-chain of methionine is highly prone to oxidation, even in vivo, with redox changes of these residues potentially altering protein function and interfering with its use as a substrate. An entire family of enzymes, methionine sulfoxide reductases, have evolved in aerobic organisms to regulate the redox status of methionine. We tested the role of methionine sulfoxide reductase A (MsrA) in the physiological and metabolic benefits of MR. After three months of MR, mice lacking MsrA (MsrA KO) showed significant loss of weight, including both fat and lean mass, in comparison to wild-type mice under MR. Both MsrA KO and wild-type mice responded to MR with improvements to both glucose and insulin tolerance. However, MR MsrA KO mice showed lower HbA1c and reduced leptin compared to MR wild-type mice. Overall, our results show mice lacking MsrA have a stronger response to MR suggesting that methionine redox may play an important role in some of the mechanisms responsible for these metabolic outcomes. Further studies clarify whether MsrA could also be a potential regulator of the longevity benefits of MR.


Author(s):  
Méry Marimoutou ◽  
Danielle A. Springer ◽  
Chengyu Liu ◽  
Geumsoo Kim ◽  
Rodney Levine

Methionine 77 in calmodulin can be stereospecifically oxidized to methionine sulfoxide by mammalian methionine sulfoxide reductase A. Whether this has in vivo significance is unknown. We therefore created a mutant mouse in which wild-type calmodulin-1 was replaced by a calmodulin containing a mimic of methionine sulfoxide at residue 77. Total calmodulin levels were unchanged in the homozygous M77Q mutant, which is viable and fertile. No differences were observed on learning tests, including the Morris water maze and associative learning. Cardiac stress test results were also the same for mutant and wild type mice. .However, young male and female mice were 20% smaller than wild type mice, although food intake was normal for their weight. Young M77Q mice were notably more active and exploratory than wild type mice. This behavior difference was objectively documented on the treadmill and open field tests. The mutant mice ran 20% longer on the treadmill than controls, and in the open field test, the mutant mice explored more than controls and exhibited reduced anxiety These phenotypic differences bore a similarity to those observed in mice lacking calcium/calmodulin kinase Iiα (CaMKIIα). We then showed that M77Q calmodulin was less effective in activating CaMKIIα than wild type calmodulin. Thus, characterization of the phenotype of a mouse expressing a constitutively active mimic of calmodulin led to the identification of the first calmodulin target that can be differentially regulated by the oxidation state of Met77. We conclude that reversible oxidation of methionine 77 in calmodulin by MSRA can regulate cellular function.


Antioxidants ◽  
2018 ◽  
Vol 7 (10) ◽  
pp. 140 ◽  
Author(s):  
Méry Marimoutou ◽  
Danielle Springer ◽  
Chengyu Liu ◽  
Geumsoo Kim ◽  
Rodney Levine

Methionine 77 in calmodulin can be stereospecifically oxidized to methionine sulfoxide by mammalian methionine sulfoxide reductase A. Whether this has in vivo significance is unknown. We therefore created a mutant mouse in which wild type calmodulin-1 was replaced by a calmodulin containing a mimic of methionine sulfoxide at residue 77. Total calmodulin levels were unchanged in the homozygous M77Q mutant, which is viable and fertile. No differences were observed on learning tests, including the Morris water maze and associative learning. Cardiac stress test results were also the same for mutant and wild type mice. However, young male and female mice were 20% smaller than wild type mice, although food intake was normal for their weight. Young M77Q mice were notably more active and exploratory than wild type mice. This behavior difference was objectively documented on the treadmill and open field tests. The mutant mice ran 20% longer on the treadmill than controls and in the open field test, the mutant mice explored more than controls and exhibited reduced anxiety. These phenotypic differences bore a similarity to those observed in mice lacking calcium/calmodulin kinase IIα (CaMKIIα). We then showed that MetO77 calmodulin was less effective in activating CaMKIIα than wild type calmodulin. Thus, characterization of the phenotype of a mouse expressing a constitutively active mimic of calmodulin led to the identification of the first calmodulin target that can be differentially regulated by the oxidation state of Met77. We conclude that reversible oxidation of methionine 77 in calmodulin by MSRA has the potential to regulate cellular function.


1998 ◽  
Vol 180 (10) ◽  
pp. 2694-2700 ◽  
Author(s):  
Christopher S. Hayes ◽  
Berenice Illades-Aguiar ◽  
Lilliam Casillas-Martinez ◽  
Peter Setlow

ABSTRACT Methionine residues in α/β-type small, acid-soluble spore proteins (SASP) of Bacillus species were readily oxidized to methionine sulfoxide in vitro by t-butyl hydroperoxide (tBHP) or hydrogen peroxide (H2O2). These oxidized α/β-type SASP no longer bound to DNA effectively, but DNA binding protected α/β-type SASP against methionine oxidation by peroxides in vitro. Incubation of an oxidized α/β-type SASP with peptidyl methionine sulfoxide reductase (MsrA), which can reduce methionine sulfoxide residues back to methionine, restored the α/β-type SASP’s ability to bind to DNA. Both tBHP and H2O2 caused some oxidation of the two methionine residues of an α/β-type SASP (SspC) in spores ofBacillus subtilis, although one methionine which is highly conserved in α/β-type SASP was only oxidized to a small degree. However, much more methionine sulfoxide was generated by peroxide treatment of spores carrying a mutant form of SspC which has a lower affinity for DNA. MsrA activity was present in wild-type B. subtilis spores. However, msrA mutant spores were no more sensitive to H2O2 than were wild-type spores. The major mechanism operating for dealing with oxidative damage to α/β-type SASP in spores is DNA binding, which protects the protein’s methionine residues from oxidation both in vitro and in vivo. This may be important in vivo since α/β-type SASP containing oxidized methionine residues no longer bind DNA well and α/β-type SASP-DNA binding is essential for long-term spore survival.


2008 ◽  
Vol 190 (17) ◽  
pp. 5806-5813 ◽  
Author(s):  
Emmanuel Denou ◽  
Raymond David Pridmore ◽  
Marco Ventura ◽  
Anne-Cécile Pittet ◽  
Marie-Camille Zwahlen ◽  
...  

ABSTRACT Two independent isolates of the gut commensal Lactobacillus johnsonii were sequenced. These isolates belonged to the same clonal lineage and differed mainly by a 40.8-kb prophage, LJ771, belonging to the Sfi11 phage lineage. LJ771 shares close DNA sequence identity with Lactobacillus gasseri prophages. LJ771 coexists as an integrated prophage and excised circular phage DNA, but phage DNA packaged into extracellular phage particles was not detected. Between the phage lysin gene and attR a likely mazE (“antitoxin”)/pemK (“toxin”) gene cassette was detected in LJ771 but not in the L. gasseri prophages. Expressed pemK could be cloned in Escherichia coli only together with the mazE gene. LJ771 was shown to be highly stable and could be cured only by coexpression of mazE from a plasmid. The prophage was integrated into the methionine sulfoxide reductase gene (msrA) and complemented the 5′ end of this gene, creating a protein with a slightly altered N-terminal sequence. The two L. johnsonii strains had identical in vitro growth and in vivo gut persistence phenotypes. Also, in an isogenic background, the presence of the prophage resulted in no growth disadvantage.


2019 ◽  
Vol 116 (48) ◽  
pp. 24359-24365 ◽  
Author(s):  
Tabea C. Fricke ◽  
Frank Echtermeyer ◽  
Johannes Zielke ◽  
Jeanne de la Roche ◽  
Milos R. Filipovic ◽  
...  

Thermosensitive transient receptor potential (TRP) ion channels detect changes in ambient temperature to regulate body temperature and temperature-dependent cellular activity. Rodent orthologs of TRP vanilloid 2 (TRPV2) are activated by nonphysiological heat exceeding 50 °C, and human TRPV2 is heat-insensitive. TRPV2 is required for phagocytic activity of macrophages which are rarely exposed to excessive heat, but what activates TRPV2 in vivo remains elusive. Here we describe the molecular mechanism of an oxidation-induced temperature-dependent gating of TRPV2. While high concentrations of H2O2 induce a modest sensitization of heat-induced inward currents, the oxidant chloramine-T (ChT), ultraviolet A light, and photosensitizing agents producing reactive oxygen species (ROS) activate and sensitize TRPV2. This oxidation-induced activation also occurs in excised inside-out membrane patches, indicating a direct effect on TRPV2. The reducing agent dithiothreitol (DTT) in combination with methionine sulfoxide reductase partially reverses ChT-induced sensitization, and the substitution of the methionine (M) residues M528 and M607 to isoleucine almost abolishes oxidation-induced gating of rat TRPV2. Mass spectrometry on purified rat TRPV2 protein confirms oxidation of these residues. Finally, macrophages generate TRPV2-like heat-induced inward currents upon oxidation and exhibit reduced phagocytosis when exposed to the TRP channel inhibitor ruthenium red (RR) or to DTT. In summary, our data reveal a methionine-dependent redox sensitivity of TRPV2 which may be an important endogenous mechanism for regulation of TRPV2 activity and account for its pivotal role for phagocytosis in macrophages.


mBio ◽  
2013 ◽  
Vol 4 (6) ◽  
Author(s):  
Marcia M. Hobbs ◽  
James E. Anderson ◽  
Jacqueline T. Balthazar ◽  
Justin L. Kandler ◽  
Russell W. Carlson ◽  
...  

ABSTRACT Phosphoethanolamine (PEA) on Neisseria gonorrhoeae lipid A influences gonococcal inflammatory signaling and susceptibility to innate host defenses in in vitro models. Here, we evaluated the role of PEA-decorated gonococcal lipid A in competitive infections in female mice and in male volunteers. We inoculated mice and men with mixtures of wild-type N. gonorrhoeae and an isogenic mutant that lacks the PEA transferase, LptA. LptA production conferred a marked survival advantage for wild-type gonococci in the murine female genital tract and in the human male urethra. Our studies translate results from test tube to animal model and into the human host and demonstrate the utility of the mouse model for studies of virulence factors of the human-specific pathogen N. gonorrhoeae that interact with non-host-restricted elements of innate immunity. These results validate the use of gonococcal LptA as a potential target for development of novel immunoprophylactic strategies or antimicrobial treatments. IMPORTANCE Gonorrhea is one of the most common bacterial sexually transmitted infections, and increasing antibiotic resistance threatens the use of currently available antimicrobial therapies. In this work, encompassing in vitro studies and in vivo studies of animal and human models of experimental genital tract infection, we document the importance of lipid A’s structure, mediated by a single bacterial enzyme, LptA, in enhancing the fitness of Neisseria gonorrhoeae. The results of these studies suggest that novel agents targeting LptA may offer urgently needed prevention or treatment strategies for gonorrhea.


2016 ◽  
Vol 310 (6) ◽  
pp. E388-E393 ◽  
Author(s):  
Jackob Moskovitz ◽  
Fang Du ◽  
Connor F. Bowman ◽  
Shirley S. Yan

Accumulation of oxidized proteins, and especially β-amyloid (Aβ), is thought to be one of the common causes of Alzheimer's disease (AD). The current studies determine the effect of an in vivo methionine sulfoxidation of Aβ through ablation of the methionine sulfoxide reductase A (MsrA) in a mouse model of AD, a mouse that overexpresses amyloid precursor protein (APP) and Aβ in neurons. Lack of MsrA fosters the formation of methionine sulfoxide in proteins, and thus its ablation in the AD-mouse model will increase the formation of methionine sulfoxide in Aβ. Indeed, the novel MsrA-deficient APP mice ( APP+/ MsrAKO) exhibited higher levels of soluble Aβ in brain compared with APP+ mice. Furthermore, mitochondrial respiration and the activity of cytochrome c oxidase were compromised in the APP+/ MsrAKO compared with control mice. These results suggest that lower MsrA activity modifies Aβ solubility properties and causes mitochondrial dysfunction, and augmenting its activity may be beneficial in delaying AD progression.


1998 ◽  
Vol 180 (9) ◽  
pp. 2280-2284 ◽  
Author(s):  
Carolina Sousa ◽  
Pavel Kotrba ◽  
Tomas Ruml ◽  
Angel Cebolla ◽  
Víctor De Lorenzo

ABSTRACT Yeast (CUP1) and mammalian (HMT-1A) metallothioneins (MTs) have been efficiently expressed in Escherichia coli as fusions to the outer membrane protein LamB. A 65-amino-acid sequence from the CUP1 protein of Saccharomyces cerevisiae (yeast [Y] MT) was genetically inserted in permissive site 153 of the LamB sequence, which faces the outer medium. A second LamB fusion at position 153 was created with 66 amino acids recruited from the form of human (H) MT that is predominant in the adipose tissue, HMT-1A. Both LamB153-YMT and LamB153-HMT hybrids were produced in vivo as full-length proteins, without any indication of instability or proteolytic degradation. Each of the two fusion proteins was functional as the port of entry of lambda phage variants, suggesting maintenance of the overall topology of the wild-type LamB. Expression of the hybrid proteins in vivo multiplied the natural ability of E. colicells to bind Cd2+ 15- to 20-fold, in good correlation with the number of metal-binding centers contributed by the MT moiety of the fusions.


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