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1.
Int J Gynecol Pathol ; 2024 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-39078313

RESUMO

Endometriosis is a common condition, with the ovary being the most common anatomic site. Endometriosis-particularly in the ovary-is associated with a risk of malignant progression, with a histologic spectrum of lesions from benign to malignant. Recently, a panel of 3 markers consisting of ß-catenin, PAX2, and PTEN has been described as a potentially useful diagnostic adjunct in the diagnosis of intrauterine endometrioid neoplasia, where aberrancy for one or more of the markers is strongly associated with neoplasia. Here, we applied the panel to ovarian endometrioid lesions, including endometriosis, endometriosis with flat cytologic atypia, endometrioid borderline tumors, and endometrioid adenocarcinoma (n=85 cases in total). The incidence of aberrancy for the 3 markers increased along this putative neoplastic spectrum, arguing for a role of each of the markers in the neoplastic transformation of ovarian endometriosis. Just 1/32 (3%) of cases of nonatypical endometriosis was marker-aberrant, and this case was aberrant only for PAX2. One of 5 cases (20%) of endometriosis with atypia was marker-aberrant (both PAX2 and PTEN), supporting prior findings that some cases of flat atypia may represent bona fide precursor lesions. Of 19 endometrioid borderline tumors, 10 (53%) were aberrant for one or more markers, with PAX2 being the most frequently aberrant. Of 29 endometrioid adenocarcinomas, 28 (96.6%) were aberrant for at least 1 marker, with PAX2 again the most frequently aberrant. Patterns of aberrancy were well-preserved in areas of nonatypical endometriosis adjacent to borderline tumor or adenocarcinoma, supporting a biological origin in a common marker-aberrant precursor. The findings show that the biomarker panel could be of some diagnostic utility in the characterization of ovarian endometrioid neoplasia, such as in the diagnosis of endometrioid borderline tumor, distinguishing endometrioid from nonendometrioid lesions, or in identifying other types of early precursors at a higher risk of malignant transformation.

2.
PLoS Genet ; 17(3): e1009483, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33784295

RESUMO

Conventionally viewed as male hormone, androgens play a critical role in female fertility. Although androgen receptors (AR) are transcription factors, to date very few direct transcriptional targets of ARs have been identified in the ovary. Using mouse models, this study provides three critical insights about androgen-induced gene regulation in the ovary and its impact on female fertility. First, RNA-sequencing reveals a number of genes and biological processes that were previously not known to be directly regulated by androgens in the ovary. Second, androgens can also influence gene expression by decreasing the tri-methyl mark on lysine 27 of histone3 (H3K27me3), a gene silencing epigenetic mark. ChIP-seq analyses highlight that androgen-induced modulation of H3K27me3 mark within gene bodies, promoters or distal enhancers have a much broader impact on ovarian function than the direct genomic effects of androgens. Third, androgen-induced decrease of H3K27me3 is mediated through (a) inhibiting the expression and activity of Enhancer of Zeste Homologue 2 (EZH2), a histone methyltransferase that promotes tri-methylation of K27 and (b) by inducing the expression of a histone demethylase called Jumonji domain containing protein-3 (JMJD3/KDM6B), responsible for removing the H3K27me3 mark. Androgens through the PI3K/Akt pathway, in a transcription-independent fashion, increase hypoxia-inducible factor 1 alpha (HIF1α) protein levels, which in turn induce JMJD3 expression. Furthermore, proof of concept studies involving in vivo knockdown of Ar in the ovary and ovarian (granulosa) cell-specific Ar knockout mouse model show that ARs regulate the expression of key ovarian genes through modulation of H3K27me3.


Assuntos
Androgênios/metabolismo , Proteína Potenciadora do Homólogo 2 de Zeste/metabolismo , Regulação da Expressão Gênica , Histonas/metabolismo , Histona Desmetilases com o Domínio Jumonji/metabolismo , Ovário/metabolismo , Androgênios/farmacologia , Animais , Biologia Computacional/métodos , Feminino , Perfilação da Expressão Gênica , Regulação da Expressão Gênica/efeitos dos fármacos , Células da Granulosa/efeitos dos fármacos , Células da Granulosa/metabolismo , Camundongos , Ovário/efeitos dos fármacos , Fosfatidilinositol 3-Quinases/metabolismo , Regiões Promotoras Genéticas , Proteínas Proto-Oncogênicas c-akt , Transcriptoma
3.
Biol Reprod ; 107(3): 813-822, 2022 09 12.
Artigo em Inglês | MEDLINE | ID: mdl-35657015

RESUMO

The anti-Müllerian hormone (AMH) produced by the granulosa cells of growing follicles is critical for folliculogenesis and is clinically used as a diagnostic and prognostic marker of female fertility. Previous studies report that AMH-pretreatment in mice creates a pool of quiescent follicles that are released following superovulation, resulting in an increased number of ovulated oocytes. However, the quality and developmental competency of oocytes derived from AMH-induced accumulated follicles as well as the effect of AMH treatment on live birth are not known. This study reports that AMH priming positively affects oocyte maturation and early embryonic development culminating in higher number of live births. Our results show that AMH treatment results in good-quality oocytes with greater developmental competence that enhances embryonic development resulting in blastocysts with higher gene expression. The transcriptomic analysis of oocytes from AMH-primed mice compared with those of control mice reveal that AMH upregulates a large number of genes and pathways associated with oocyte quality and embryonic development. Mitochondrial function is the most affected pathway by AMH priming, which is supported by more abundant active mitochondria, mitochondrial DNA content and adenosine triphosphate levels in oocytes and embryos isolated from AMH-primed animals compared with control animals. These studies for the first time provide an insight into the overall impact of AMH on female fertility and highlight the critical knowledge necessary to develop AMH as a therapeutic option to improve female fertility.


Assuntos
Hormônio Antimülleriano , Coeficiente de Natalidade , Animais , Hormônio Antimülleriano/genética , Hormônio Antimülleriano/metabolismo , Desenvolvimento Embrionário , Feminino , Nascido Vivo , Camundongos , Oócitos/metabolismo , Folículo Ovariano/metabolismo , Gravidez
4.
J Dairy Sci ; 105(1): 842-855, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34696909

RESUMO

Intense and protracted adipose tissue (AT) fat mobilization increases the risk of metabolic and inflammatory periparturient diseases in dairy cows. This vulnerability increases when cows have endotoxemia-common during periparturient diseases such as mastitis, metritis, and pneumonia-but the mechanisms are unknown. Fat mobilization intensity is determined by the balance between lipolysis and lipogenesis. Around parturition, the rate of lipolysis surpasses that of lipogenesis, leading to enhanced free fatty acid release into the circulation. We hypothesized that exposure to endotoxin (ET) increases AT lipolysis by activation of classic and inflammatory lipolytic pathways and reduction of insulin sensitivity. In experiment 1, subcutaneous AT (SCAT) explants were collected from periparturient (n = 12) Holstein cows at 11 ± 3.6 d (mean ± SE) before calving, and 6 ± 1 d and 13 ± 1.4 d after parturition. Explants were treated with the endotoxin lipopolysaccharide (LPS; 20 µg/mL; basal = 0 µg/mL) for 3 h. The effect of LPS on lipolysis was assessed in the presence of the ß-adrenergic agonist and promoter of lipolysis isoproterenol (ISO; 1 µM; LPS+ISO). In experiment 2, SCAT explants were harvested from 24 nonlactating, nongestating multiparous Holstein dairy cows and exposed to the same treatments as in experiment 1 for 3 and 7 h. The effect of LPS on the antilipolytic responses induced by insulin (INS = 1 µL/L, LPS+INS) was established during ISO stimulation [ISO+INS, LPS+ISO+INS]. The characterization of lipolysis included the quantification of glycerol release and the assessment of markers of lipase activity [adipose triglyceride lipase (ATGL), hormone-sensitive lipase (HSL), and phosphorylated HSL Ser563 (pHSL)], and insulin pathway activation (AKT, pAKT) using capillary electrophoresis. Inflammatory gene networks were evaluated by real-time quantitative PCR. In periparturient cows, LPS increased AT lipolysis by 67 ± 12% at 3 h across all time points compared with basal. In nonlactating cows, LPS was an effective lipolytic agent at 3 h and 7 h, increasing glycerol release by 115 ± 18% and 68.7 ± 16%, respectively, relative to basal. In experiment 2, LPS enhanced ATGL activity with minimal HSL activation at 3 h. In contrast, at 7 h, LPS increased HSL phosphorylation (i.e., HSL activity) by 123 ± 11%. The LPS-induced HSL lipolytic activity at 7 h coincided with the activation of the MEK/ERK inflammatory pathway. In experiment 2, INS reduced the lipolytic effect of ISO (ISO+INS: -63 ± 18%) and LPS (LPS+INS: -45.2 ± 18%) at 3 h. However, the antilipolytic effect of INS was lost in the presence of LPS at 7 h (LPS+INS: -16.3 ± 16%) and LPS+ISO+INS at 3 and 7 h (-3.84 ± 23.6% and -21.2 ± 14.6%). Accordingly, LPS reduced pAKT:AKT (0.11 ± 0.07) compared with basal (0.18 ± 0.05) at 7 h. Our results indicated that exposure to LPS activated the classic and inflammatory lipolytic pathways and reduced insulin sensitivity in SCAT. These data provide evidence that during endotoxemia, dairy cows may be more susceptible to lipolysis dysregulation and loss of adipocyte sensitivity to the antilipolytic action of insulin.


Assuntos
Doenças dos Bovinos , Resistência à Insulina , Tecido Adiposo/metabolismo , Animais , Bovinos , Doenças dos Bovinos/metabolismo , Feminino , Lipólise , Lipopolissacarídeos/metabolismo , Esterol Esterase/metabolismo
5.
Biol Reprod ; 102(5): 1045-1054, 2020 04 24.
Artigo em Inglês | MEDLINE | ID: mdl-31930385

RESUMO

Maternal perturbations or sub-optimal conditions during fetal development can predispose the offspring to diseases in adult life. Animal and human studies show that prenatal androgen excess may be an underlying cause of polycystic ovary syndrome (PCOS) later in life. In women, PCOS is a common fertility disorder with comorbid metabolic dysfunction. Here, using a sheep model of PCOS phenotype, we elucidate the epigenetic changes induced by prenatal (30-90 day) testosterone (T) treatment and its effect on gene expression in fetal day 90 (D90) and adult year 2 (Y2) ovaries. RNA-seq study shows 65 and 99 differentially regulated genes in prenatal T-treated fetal and adult ovaries, respectively. Interestingly, there were no differences in gene inducing histone marks H3K27ac, H3K9ac, and H3K4me3 or in gene silencing marks, H3K27me3 and H3K9me3 in the fetal D90 ovaries of control and excess T-exposed fetuses. In contrast, except for H3K4me3 and H3K27me3, all the other histone marks were upregulated in the prenatal T-treated adult Y2 ovary. Chromatin immunoprecipitation (ChIP) studies in adult Y2 ovaries established a direct relationship between the epigenetic modifications with the upregulated and downregulated genes obtained from RNA-seq. Results show increased gene inducing marks, H3K27ac and H3K9ac, on the promoter region of upregulated genes while gene silencing mark, H3K9me3, was also significantly increased on the downregulated genes. This study provides a mechanistic insight into prenatal T-induced developmental programming and its effect on ovarian gene expression that may contribute to reproductive dysfunction and development of PCOS in adult life.


Assuntos
Epigênese Genética , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Ovário/efeitos dos fármacos , Ovário/fisiologia , Ovinos/fisiologia , Testosterona/farmacologia , Animais , Feminino , Desenvolvimento Fetal/efeitos dos fármacos , Gravidez , Efeitos Tardios da Exposição Pré-Natal , Ovinos/embriologia
6.
BMC Microbiol ; 14: 49, 2014 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-24568688

RESUMO

BACKGROUND: Pathogenic serotypes of Vibrio cholerae cause the life-threatening diarrheal disease cholera. The increasing development of bacterial resistances against the known antibiotics necessitates the search for new antimicrobial compounds and targets for this pathogen. RESULTS: A high-throughput screening assay with a Vibrio cholerae reporter strain constitutively expressing green fluorescent protein (GFP) was developed and applied in the investigation of the growth inhibitory effect of approximately 28,300 structurally diverse natural compounds and synthetic small molecules. Several compounds with activities in the low micromolar concentration range were identified. The most active structure, designated vz0825, displayed a minimal inhibitory concentration (MIC) of 1.6 µM and a minimal bactericidal concentration (MBC) of 3.2 µM against several strains of V. cholerae and was specific for this pathogen. Mutants with reduced sensitivity against vz0825 were generated and whole genome sequencing of 15 pooled mutants was carried out. Comparison with the genome of the wild type strain identified the gene VC_A0531 (GenBank: AE003853.1) as the major site of single nucleotide polymorphisms in the resistant mutants. VC_A0531 is located on the small chromosome of V. cholerae and encodes the osmosensitive K+-channel sensor histidine kinase (KdpD). Nucleotide exchange of the major mutation site in the wild type strain confirmed the sensitive phenotype. CONCLUSION: The reporter strain MO10 pG13 was successfully used for the identification of new antibacterial compounds against V. cholerae. Generation of resistant mutants and whole genome sequencing was carried out to identify the histidine kinase KdpD as a novel antimicrobial target.


Assuntos
Antibacterianos/isolamento & purificação , Antibacterianos/farmacologia , Proteínas de Bactérias/antagonistas & inibidores , Inibidores Enzimáticos/isolamento & purificação , Inibidores Enzimáticos/farmacologia , Vibrio cholerae/efeitos dos fármacos , Vibrio cholerae/crescimento & desenvolvimento , Proteínas de Bactérias/genética , Análise Mutacional de DNA , Farmacorresistência Bacteriana , Genoma Bacteriano , Ensaios de Triagem em Larga Escala , Testes de Sensibilidade Microbiana , Viabilidade Microbiana/efeitos dos fármacos , Mutação , Polimorfismo de Nucleotídeo Único , Proteínas Quinases/genética , Vibrio cholerae/fisiologia
7.
ChemSusChem ; : e202401463, 2024 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-39188076

RESUMO

Creation of an efficient and cost-effective proton exchange membrane (PEM) has emerged as a propitious solution to address the challenges of renewable energy development. Coordination polymers (CPs) have garnered significant interest due to their multifunctional applications and moldability, along with long-range order. To leverage the potential of CPs in fuel cells, it is essential to integrate microcrystalline CPs into organic polymers to prepare membranes and avoid grain boundary issues. In this study, we designed and synthesized CPs containing imidazole and sulfonate moieties via gel-to-crystal transformation. The integration of CPs into the PVDF-PVP matrix resulted in superprotonic conductivity in the order of 10-2 S cm-1 at room temperature (30 °C) and 98 % RH. The proton conductivity achieved with CP-integrated composite membrane was 4.69×10-2 S cm-1 at 80 °C and 98 % RH, the highest among all CP/MOF-integrated PVDF-PVP membranes under hydrous conditions. The excellent compatibility of CPs with PVDF-PVP produced highly flexible membranes with superior mechanical, chemical, and thermal stability. About 25 times higher proton conductivity value was achieved with membrane, compared to intrinsic CPs, at RT and 98 % RH. Thus, we present a cost-effective CP-integrated mixed-matrix membrane with superprotonic conductivity and long-term durability for cutting-edge fuel cell development.

8.
Endocrinology ; 163(5)2022 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-35396990

RESUMO

In females, reproductive success is dependent on the expression of a number of genes regulated at different levels, one of which is through epigenetic modulation. How a specific epigenetic modification regulates gene expression and their downstream effect on ovarian function are important for understanding the female reproductive process. The trimethylation of histone3 at lysine27 (H3K27me3) is associated with gene repression. JMJD3 (or KDM6b), a jumonji domain-containing histone demethylase specifically catalyzes the demethylation of H3K27me3, that positively influences gene expression. This study reports that the expression of JMJD3 specifically in the ovarian granulosa cells (GCs) is critical for maintaining normal female fertility. Conditional deletion of Jmjd3 in the GCs results in a decreased number of total healthy follicles, disrupted estrous cycle, and increased follicular atresia culminating in subfertility and premature ovarian failure. At the molecular level, the depletion of Jmjd3 and RNA-seq analysis reveal that JMJD3 is essential for mitochondrial function. JMJD3-mediated reduction of H3K27me3 induces the expression of Lif (Leukemia inhibitory factor) and Ctnnb1 (ß-catenin), that in turn regulate the expression of key mitochondrial genes critical for the electron transport chain. Moreover, mitochondrial DNA content is also significantly decreased in Jmjd3 null GCs. Additionally, we have uncovered that the expression of Jmjd3 in GCs decreases with age, both in mice and in humans. Thus, in summary, our studies highlight the critical role of JMJD3 in nuclear-mitochondrial genome coordination that is essential for maintaining normal ovarian function and female fertility and underscore a potential role of JMJD3 in female reproductive aging.


Assuntos
Atresia Folicular , Histonas , Histona Desmetilases com o Domínio Jumonji/metabolismo , Animais , Feminino , Fertilidade/genética , Histonas/metabolismo , Humanos , Histona Desmetilases com o Domínio Jumonji/genética , Camundongos , Ovário/metabolismo
9.
Endocrinology ; 163(10)2022 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-35933634

RESUMO

In women, excess androgen causes polycystic ovary syndrome (PCOS), a common fertility disorder with comorbid metabolic dysfunctions including diabetes, obesity, and nonalcoholic fatty liver disease. Using a PCOS mouse model, this study shows that chronic high androgen levels cause hepatic steatosis while hepatocyte-specific androgen receptor (AR)-knockout rescues this phenotype. Moreover, through RNA-sequencing and metabolomic studies, we have identified key metabolic genes and pathways affected by hyperandrogenism. Our studies reveal that a large number of metabolic genes are directly regulated by androgens through AR binding to androgen response element sequences on the promoter region of these genes. Interestingly, a number of circadian genes are also differentially regulated by androgens. In vivo and in vitro studies using a circadian reporter [Period2::Luciferase (Per2::LUC)] mouse model demonstrate that androgens can directly disrupt the hepatic timing system, which is a key regulator of liver metabolism. Consequently, studies show that androgens decrease H3K27me3, a gene silencing mark on the promoter of core clock genes, by inhibiting the expression of histone methyltransferase, Ezh2, while inducing the expression of the histone demethylase, JMJD3, which is responsible for adding and removing the H3K27me3 mark, respectively. Finally, we report that under hyperandrogenic conditions, some of the same circadian/metabolic genes that are upregulated in the mouse liver are also elevated in nonhuman primate livers. In summary, these studies not only provide an overall understanding of how hyperandrogenism associated with PCOS affects liver gene expression and metabolism but also offer insight into the underlying mechanisms leading to hepatic steatosis in PCOS.


Assuntos
Hiperandrogenismo , Hepatopatia Gordurosa não Alcoólica , Síndrome do Ovário Policístico , Androgênios/metabolismo , Androgênios/farmacologia , Animais , Modelos Animais de Doenças , Epigênese Genética , Feminino , Histonas/metabolismo , Humanos , Hiperandrogenismo/complicações , Camundongos , Hepatopatia Gordurosa não Alcoólica/complicações , Hepatopatia Gordurosa não Alcoólica/genética , Síndrome do Ovário Policístico/metabolismo
10.
Sci Rep ; 11(1): 20956, 2021 10 25.
Artigo em Inglês | MEDLINE | ID: mdl-34697337

RESUMO

The vagina plays a critical role in supporting the pelvic organs and loss of support leads to pelvic organ prolapse. It is unknown what microstructural changes influence prolapse progression nor how decreased elastic fibers contributes to vaginal remodeling and smooth muscle contractility. The objective for this study was to evaluate the effect of fibulin-5 haploinsufficiency, and deficiency with progressive prolapse on the biaxial contractile and biomechanical function of the murine vagina. Vaginas from wildtype (n = 13), haploinsufficient (n = 13), and deficient mice with grade 1 (n = 9) and grade 2 or 3 (n = 9) prolapse were explanted for biaxial contractile and biomechanical testing. Multiaxial histology (n = 3/group) evaluated elastic and collagen fiber microstructure. Western blotting quantified protein expression (n = 6/group). A one-way ANOVA or Kruskal-Wallis test evaluated statistical significance. Pearson's or Spearman's test determined correlations with prolapse grade. Axial contractility decreased with fibulin-5 deficiency and POP (p < 0.001), negatively correlated with prolapse grade (ρ = - 0.80; p < 0.001), and positively correlated with muscularis elastin area fraction (ρ = - 0.78; p = 0.004). Circumferential (ρ = 0.71; p < 0.001) and axial (ρ = 0.69; p < 0.001) vaginal wall stresses positively correlated with prolapse grade. These findings demonstrated that fibulin-5 deficiency and prolapse progression decreased vaginal contractility and increased vaginal wall stress. Future work is needed to better understand the processes that contribute to prolapse progression in order to guide diagnostic, preventative, and treatment strategies.


Assuntos
Proteínas da Matriz Extracelular/genética , Proteínas da Matriz Extracelular/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Prolapso Uterino/fisiopatologia , Vagina/fisiopatologia , Animais , Fenômenos Biomecânicos , Modelos Animais de Doenças , Progressão da Doença , Feminino , Haploinsuficiência , Humanos , Camundongos , Estresse Mecânico , Prolapso Uterino/genética , Prolapso Uterino/metabolismo , Vagina/metabolismo
11.
Endocrinology ; 159(9): 3433-3445, 2018 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-30060157

RESUMO

Anti-Müllerian hormone (AMH) produced by ovarian granulosa cells (GCs) plays a crucial role in ovarian function. It is used as a diagnostic and/or prognostic marker of fertility as well as for pathophysiological conditions in women. In this study, we investigated the underlying mechanism for regulation of AMH expression in GCs using primary mouse GCs and a human GC tumor-derived KGN cell line. We find that growth differentiation factor 9 (GDF9) and bone morphogenetic factor 15 (BMP15) together (GDF9 + BMP15), but not when tested separately, significantly induce AMH expression in vitro and in vivo (serum AMH). Our results show that GDF9 + BMP15 through the PI3K/Akt and Smad2/3 pathways synergistically recruit the coactivator p300 on the AMH promoter region that promotes acetylation of histone 3 lysine 27 (H3K27ac), facilitating AMH/Amh expression. Intriguingly, we also find that FSH inhibits GDF9 + BMP15-induced increase of AMH/Amh expression. This inhibition occurs through FSH-induced protein kinase A/SF1-mediated expression of gonadotropin inducible ovarian transcription factor 1, a transcriptional repressor, that recruits histone deacetylase 2 to deacetylate H3K27ac, resulting in the suppression of AMH/Amh expression. Furthermore, we report that ovarian Amh mRNA levels are significantly higher in Fshß-null mice (Fshß-/-) compared with those in wild-type (WT) mice. In addition, ovarian Amh mRNA levels are restored in Fshß-null mice expressing a human WT FSHß transgene (FSHß-/-hFSHßWT). Our study provides a mechanistic insight into the regulation of AMH expression that has many implications in female reproduction/fertility.


Assuntos
Hormônio Antimülleriano/genética , Proteína Morfogenética Óssea 15/metabolismo , Células da Granulosa/metabolismo , Fator 9 de Diferenciação de Crescimento/metabolismo , Oócitos/metabolismo , Ovário/metabolismo , Acetilação , Animais , Hormônio Antimülleriano/metabolismo , Linhagem Celular Tumoral , Feminino , Subunidade beta do Hormônio Folículoestimulante/genética , Regulação da Expressão Gênica , Código das Histonas , Humanos , Camundongos , Camundongos Knockout , Camundongos Transgênicos , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , RNA Mensageiro/metabolismo , Transdução de Sinais , Proteína Smad2/metabolismo , Proteína Smad3/metabolismo
12.
Pathog Dis ; 74(8)2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-27650573

RESUMO

Orthologs search identified that the Vibrio cholerae gluconate (Gnt) utilization system minimally consisted of the Entner-Doudoroff (ED) pathway (edd and eda) and three other genes, namely gntU, gntK and gntR This system appeared unique by genomic organization of component genes into two operons transcribed in opposite directions. In silico analysis indicated GntU as an inner-membrane protein functioning for transport and GntK as a kinase with cytosolic localization that generates Gnt6P, which is then metabolized through the ED pathway. Enzyme 6-phosphogluconate dehydratase encoded by edd converts Gnt6P to 2-keto-3-deoxy-6-phosphogluconate (KDPG), which is metabolized by the action of KDPG-aldolase encoded by eda Transcriptional upregulation of the Gnt utilization genes in the gntR mutant matched well to a predicted repressor role of GntR. GntR displayed DNA binding to a region in the promoters of two bi-directionally transcribed operons. Growth defect of mutants in Gnt-supplemented media confirmed obligate involvement of these genes in Gnt utilization and such defect was restored upon complementation. Defective Gnt utilization resulted in attenuation of colonization potential and reduction of cholera toxin secretion in V. cholerae The ED pathway mutants showed the highest level of virulence attenuation. Overall, this study established a minimal requirement of the V. cholerae Gnt utilization system, which played a critical role in pathogenesis.


Assuntos
Gluconatos/metabolismo , Vibrio cholerae/fisiologia , Sequência de Aminoácidos , Animais , Cólera/microbiologia , Ordem dos Genes , Genes Bacterianos , Proteínas de Membrana Transportadoras/química , Proteínas de Membrana Transportadoras/genética , Proteínas de Membrana Transportadoras/metabolismo , Redes e Vias Metabólicas , Mutação , Óperon , Coelhos , Vibrio cholerae/patogenicidade , Virulência/genética
13.
J Med Microbiol ; 65(7): 678-687, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27174292

RESUMO

A high-throughput screening (HTS) assay was developed for identifying compounds with inhibitory effect on aphA, one of the key regulators positively controlling Vibrio cholerae pathogenesis. An inhibitory effect on aphA was expected to lead to attenuation in the secretion of the major pathogenicity factors of V. cholerae, cholera toxin and toxin co-regulated pilus. The plasmid construct pAKSB was developed with a kanamycin resistance (KmR) gene under the control of the aphA -like promoter for conferring a KmR phenotype under aphA -expressing conditions. The HTS assay was performed to identify compounds with inhibitory effect on the growth of O139 V. cholerae MO10 carrying the construct pAKSB in growth medium containing Km (30 g ml-1), but not in its absence. Of 20 338 compounds screened, six compounds were identified to inhibit the pAKSB-induced KmR phenotype and these compounds caused transcriptional inhibition of aphA in V. cholerae O139 strain MO10 as well as variant V. cholerae O1 El Tor strain NM06-058. Of the three most active substances, compound 53760866 showed lowest half-maximal cytotoxicity in a eukaryotic cell viability assay and was characterized further. Compound 53760866 caused reduction in cholera toxin secretion and expression of TcpA in vitro. The in vitro virulence attenuation corroborated well in a suckling mouse model in vivo, which showed reduction of colonization by V. cholerae NM06-058 when co-administered with 53760866. The screening method and the compounds may lead to new preventive strategies for cholera by reducing the pathogenicity of V. cholerae .


Assuntos
Antibacterianos/isolamento & purificação , Transativadores/antagonistas & inibidores , Vibrio cholerae/efeitos dos fármacos , Vibrio cholerae/patogenicidade , Fatores de Virulência/antagonistas & inibidores , Animais , Animais Recém-Nascidos , Antibacterianos/toxicidade , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Cólera/patologia , Cólera/prevenção & controle , Modelos Animais de Doenças , Fibroblastos/efeitos dos fármacos , Fibroblastos/fisiologia , Ensaios de Triagem em Larga Escala , Camundongos , Análise de Sobrevida
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