CBS-derived H2S facilitates host colonization of Vibrio cholerae by promoting the iron-dependent catalase activity of KatB.

Sensing and resisting oxidative stress is critical for Vibrio cholerae to survive in either the aquatic environment or the gastrointestinal tract. Previous studies mainly focused on the mechanisms of oxidative stress response regulation that rely on enzymatic antioxidant systems, while functions of non-enzymatic antioxidants are rarely discussed in V. cholerae. For the first time, we investigated the role of hydrogen sulfide (H2S), the simplest thiol compound, in protecting V. cholerae against oxidative stress. We found that degradation of L-cysteine by putative cystathionine ß-synthase (CBS) is the major source of endogenous H2S in V. cholerae. Our results indicate that intracellular H2S level has a positive correlation with cbs expression, while the enhanced H2S production can render V. cholerae cells less susceptible to H2O2 in vitro. Using proteome analysis and real-time qPCR assay, we found that cbs expression could stimulate the expression of several enzymatic antioxidants, including reactive oxygen species (ROS) detoxifying enzymes SodB, KatG and AhpC, the DNA protective protein DPS and the protein redox regulator Trx1. Assays of ROS detoxification capacities revealed that CBS-derived H2S could promote catalase activity at the post-translational level, especially for KatB, which serves as an important way that endogenous H2S participates in H2O2 detoxification. The enhancement of catalase activity by H2S is achieved through facilitating the uptake of iron. Adult mice experiments showed that cbs mutant has colonization defect, while either complementation of cbs or exogenous supplement of N-Acetyl-L-Cysteine restores its fitness in the host environment. Herein, we proposed that V. cholerae regulates CBS-dependent H2S production for better survival and proliferation under ROS stress.

[Kuntai capsule combined with gonadotropin releasing hormone agonist in treatment of moderate-severe endometriosis: a clinical observation].

OBJECTIVE: To observe the effect of Kuntai Capsule (KC), a Chinese patent medicine, in add-back therapy for gonadotropin-releasing hormone agonist (GnRH-a) treatment for moderate-severe endometriosis (EM). METHODS: Totally 100 patients suffering from stage III/IV EM, who were confirmed by laparoscopic surgery were randomly assigned to the GnRH-a group (A) and the KC combined GnRH-a group (B), 50 in each group. Patients in Group A were hypodermically injected with goserelin (3.6 mg), once per 4 weeks. Those in Group B additionally took KC, 4 pills each time, three times per day. The therapeutic course for all was 12 weeks. Serum levels of estradiol (E2), follicle stimulating hormone (FSH), bone gamma-carboxyglutamic-acid-containing proteins (BGP) were measured respectively. Kupperman Menopausal Index (KMI) and bone mineral density (BMD) of the lumbar vertebra were also compared between the two groups. RESULTS: Serum levels of E2 and FSH both significantly decreased in the two groups at week 12 of the treatment (P < 0.05), when compared with pre-treatment. Compared with before treatment in the same group, KMI increased in the two groups (P < 0.05). Compared with before treatment in the same group, BMI decreased in the two groups with no statistical difference (P > 0.05). Serum BGP increased after 12-week treatment (P < 0.05). Compared with Group A after treatment, serum levels of E2 and FSH both significantly increased in Group B (P < 0.05). There was no statistical difference in KMI between the two groups (P > 0.05). As for the incidence of menopausal symptoms, better effects in improving symptoms such as hot flashes, sleep disorders, and vaginal dryness were obtained in Group B than in Group A (P < 0.05). There was no significant difference in the post-pre-treatment difference of BMI between the two groups, but with statistical post-pre-treatment difference in the BGP level (P < 0.05). CONCLUSIONS: HKC combined GnRH-a could effectively reduce GnRH-a treatment induced partial low estrogen symptoms, improve increased serum BGP levels after GnRH-a therapy.