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 H 2 O 2 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 H 2 O 2 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.Neisseria gonorrhoeae is a facultative anaerobic bacterium with no environmental or animal reservoir outside of humans. N. gonorrhoeae is maintained in the human population on mucosal surfaces, including the urethra, cervix, pharynx, and rectum. Tissues of the upper reproductive tract of both males and females can also be infected. As is typical of the pyogenic cocci, N. gonorrhoeae induces an intense inflammatory response during symptomatic infections that is characterized by numerous polymorphonuclear leukocytes (PMNs) with intracellular gram-negative diplococci (21).The mechanism(s) by which the gonococcus evades oxidative killing by phagocytes is of particular interest based on evidence that a proportion of intracellular gonococci survives and even multiplies within the PMNs (5, 6, 34, 42, 54, 55) despite the induction of an intracellular respiratory burst (42, 58). Several factors protect N. gonorrhoeae from exposure to oxidative stress in vitro (reviewed in reference 43). A nonenzymatic quenching mechanism that is based on the accumulation of intracellular manganese through the MntABC transporter protects N. gonorrhoeae from H 2 O 2 and superoxide anion (52), and high levels of catalase protect gonococci from H 2 O 2 and exposure to paraquat (20,25,47). Cytochrome c peroxidase (Ccp) also increases gonococcal r...

Background: Because of the risk of performing renal biopsies in children with co-morbid conditions, we carried out this study to identify candidate protein biomarkers in the urine of HIV-infected children with renal disease.Design, setting, participants & measurements: Urine samples from HIV-infected children with biopsy proven HIVnephropathy (HIVAN; n ‫؍‬ 4), HIV-associated Hemolytic Uremic Syndrome (HIV-HUS; n ‫؍‬ 2), or no renal disease (n ‫؍‬ 3) were analyzed by two-dimensional electrophoresis (2-DE) and proteomic methods. Positive findings were confirmed in HIVinfected children with (n ‫؍‬ 20) and without (n ‫؍‬ 10) proteinuria using commercially available assays.Results: By 2-DE analysis, a single urine marker was not sufficient to distinguish children with HIVAN from the others. High urine levels of ␤ 2 -microglobulin and retinol-binding protein (RBP) suggested the presence of tubular injury. In addition, we found elevated urine levels of iron and the iron-related proteins, transferrin, hemopexin, haptoglobin, lactoferrin, and neutrophil gelatinase-associated lipocalin (NGAL), in children with HIVAN and HIV-HUS. Furthermore, we detected a significant accumulation of iron in the urine and kidneys of HIV-transgenic (Tg) rats with renal disease.Conclusion: These findings suggest that iron and iron-related proteins might be promising candidate urine biomarkers to identify HIV-infected children at risk of developing HIVAN and HIV-HUS. Moreover, based on the results of previous studies, we speculate that the release or accumulation of iron in the kidney of HIV-infected children may contribute to the rapid progression of their renal disease, and could become a new therapeutic target against HIVAN and HIV-HUS.

Human immunodeficiency virus (HIV)-infected children are at risk of developing several types of renal diseases, including HIV-associated nephropathy (HIVAN), which is usually seen during late stages of infection in children with a high viral load. This disease is defined by the presence of proteinuria associated with mesangial hyperplasia and/or global–focal segmental glomerulosclerosis combined with microcystic transformation of the renal tubules. Because HIVAN can have an insidious clinical onset, renal biopsy is the only definitive way of establishing a diagnosis. Given the risk of performing this procedure in HIV-infected children with other AIDS-defining illness, we sought to identify informative biomarkers such as growth factors in the urine of 55 HIV-infected children that might be predictive of the extent and activity of the renal lesions characteristic of HIVAN. We found that the levels of epidermal growth factor were lower in the urine of children with renal disease, whereas levels of fibroblast growth factor-2 and metalloproteinase-2 were higher as compared with those levels in infected children without renal disease. Similar changes were observed in HIV-Tg26 mice correlating with the progression of renal disease in this model of HIVAN. Our findings suggest that this urinary growth factor profile may be useful in facilitating the diagnosis of HIV-infected children at risk of developing HIVAN when interpreted in the appropriate clinical setting.

Neisseria gonorrhoeae produces several antioxidant defenses, including high levels of catalase, which may facilitate the persistence during an inflammatory response via neutralization of H 2 O 2 produced by phagocytes. In vivo testing of the role of catalase in gonococcal survival is critical since several physiological factors impact interactions between N. gonorrhoeae and polymorphonuclear leukocytes (PMNs). Here we assessed the importance of gonococcal catalase in a surrogate model of female genital tract infection. Female BALB/c mice were treated with 17-␤ estradiol to promote susceptibility to N. gonorrhoeae and inoculated intravaginally with wild-type gonococci or a catalase (kat) deletion mutant. A localized PMN influx occurred in an average of 43 and 81% of mice infected with wild-type or kat mutant gonococci, respectively, and PMNs associated with numerous wild-type or catalase-deficient bacteria were observed in vaginal smears. The combined results of six experiments showed a significant difference in the number of days wild-type bacteria were recovered compared to the catalase-deficient gonococci. However, there was much variability between experiments, and we found no correlation between PMN influx, colonization load, and clearance of wild-type or kat mutant bacteria. Estradiol treatment did not impair bacterial uptake, the luminol-dependent chemiluminescence response, or the killing capacity of isolated murine PMNs against N. gonorrhoeae or Staphylococcus aureus. Our data suggest N. gonorrhoeae is not significantly challenged by H 2 O 2 produced by PMNs in the murine lower genital tract; alternatively, redundant defense mechanisms may protect the gonococcus from reactive oxygen species during infection.