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1.
Clin Chim Acta ; 558: 119670, 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38614420

RESUMO

In recent years, there has been a global increase in cases of male infertility. There are about 30 million cases of male infertility worldwide and male reproductive health is showing rapid decline in last few decades. It is now recognized as a potential risk factor for developing certain types of cancer, particularly genitourinary malignancies like testicular and prostate cancer. Male infertility is considered a potential indicator of overall health and an early biomarker for cancer. Cases of unexplained male factor infertility have high levels of oxidative stress and oxidative DNA damage and this induces both denovo germ line mutations and epimutations due to build up of 8-hydroxy 2 deoxygunaosine abase which is highly mutagenic and also induces hypomethylation and genomic instability. Consequently, there is growing evidence to explore the various factors contributing to an increased cancer risk. Currently, the available prognostic and predictive biomarkers associated with semen characteristics and cancer risk are limited but gaining significant attention in clinical research for the diagnosis and treatment of elevated cancer risk in the individual and in offspring. The male germ cell being transcriptionally and translationally inert has a highly truncated repair mechanism and has minimal antioxidants and thus most vulnerable to oxidative injury due to environmental factors and unhealthy lifestyle and social habits. Therefore, advancing our understanding requires a thorough evaluation of the pathophysiologic mechanisms at the DNA, RNA, protein, and metabolite levels to identify key biomarkers that may underlie the pathogenesis of male infertility and associated cancer. Advanced methodologies such as genomics, epigenetics, proteomics, transcriptomics, and metabolomics stand at the forefront of cutting-edge approaches for discovering novel biomarkers, spanning from infertility to associated cancer types. Henceforth, in this review, we aim to assess the role and potential of recently identified predictive and prognostic biomarkers, offering insights into the success of assisted reproductive technologies, causes of azoospermia and idiopathic infertility, the impact of integrated holistic approach and lifestyle modifications, and the monitoring of cancer susceptibility, initiation and progression. Comprehending these biomarkers is crucial for providing comprehensive counselling to infertile men and cancer patients, along with their families.


Assuntos
Infertilidade Masculina , Humanos , Masculino , Infertilidade Masculina/genética , Infertilidade Masculina/diagnóstico , Prognóstico , Biomarcadores Tumorais/genética , Neoplasias/genética , Neoplasias/diagnóstico , Fatores de Risco , Biomarcadores/metabolismo
2.
Proc Natl Acad Sci U S A ; 121(2): e2309664121, 2024 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-38170746

RESUMO

Inorganic polyphosphate (polyP) is primarily synthesized by Polyphosphate Kinase-1 (PPK-1) and regulates numerous cellular processes, including energy metabolism, stress adaptation, drug tolerance, and microbial pathogenesis. Here, we report that polyP interacts with acyl CoA carboxylases, enzymes involved in lipid biosynthesis in Mycobacterium tuberculosis. We show that deletion of ppk-1 in M. tuberculosis results in transcriptional and metabolic reprogramming. In comparison to the parental strain, the Δppk-1 mutant strain had reduced levels of virulence-associated lipids such as PDIMs and TDM. We also observed that polyP deficiency in M. tuberculosis is associated with enhanced phagosome-lysosome fusion in infected macrophages and attenuated growth in mice. Host RNA-seq analysis revealed decreased levels of transcripts encoding for proteins involved in either type I interferon signaling or formation of foamy macrophages in the lungs of Δppk-1 mutant-infected mice relative to parental strain-infected animals. Using target-based screening and molecular docking, we have identified raloxifene hydrochloride as a broad-spectrum PPK-1 inhibitor. We show that raloxifene hydrochloride significantly enhanced the activity of isoniazid, bedaquiline, and pretomanid against M. tuberculosis in macrophages. Additionally, raloxifene inhibited the growth of M. tuberculosis in mice. This is an in-depth study that provides mechanistic insights into the regulation of mycobacterial pathogenesis by polyP deficiency.


Assuntos
Mycobacterium tuberculosis , Tuberculose , Animais , Camundongos , Simulação de Acoplamento Molecular , Cloridrato de Raloxifeno/metabolismo , Polifosfatos/metabolismo , Tuberculose/microbiologia , Redes e Vias Metabólicas , Proteínas de Bactérias/metabolismo
3.
Gene ; 894: 147983, 2024 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-37952746

RESUMO

Glaucoma stands as a leading global cause of blindness, affecting millions. It entails optic nerve damage and vision loss, categorized into open-angle and closed-angle glaucoma with subtypes like POAG, ACG, XFG, PCG, PDG, and developmental glaucoma. The pathophysiological and genetic factors behind glaucoma remain partially understood, with past studies linking intraocular pressure (IOP) levels to retinal ganglion cell death. Open-angle glaucoma involves elevated resistance to aqueous outflow via the trabecular meshwork, while angle-closure glaucoma typically sees drainage pathways obstructed by the iris. Genes have been identified for POAG, ACG, XFG, PCG, PDG, and developmental glaucoma, allowing for early-onset detection and the emergence of gene therapy as an effective treatment. Nevertheless, diagnostic and treatment options have their constraints, necessitating large-scale, well-designed studies to deepen our grasp of genetics' role in glaucoma's pathogenesis. This review delves into glaucoma's risk factors, pathophysiology, genetics, diagnosis, and available treatment options, including gene therapy. Additionally, it suggests alternative therapies like yoga and meditation as adjunct treatments for glaucoma prevention. Overall, this review advances our comprehension of the pathophysiology and genetic associations of glaucoma while highlighting the potential of gene therapy as a treatment avenue. Further research is imperative to fully elucidate the genetic mechanisms underpinning glaucoma and to devise effective treatments.


Assuntos
Glaucoma de Ângulo Aberto , Glaucoma , Humanos , Glaucoma/diagnóstico , Glaucoma/genética , Glaucoma/terapia , Malha Trabecular/metabolismo , Nervo Óptico/patologia , Pressão Intraocular/genética
4.
J Clin Med ; 12(4)2023 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-36836185

RESUMO

In humans, the gut microbiota (GM) are known to play a significant role in the metabolism of nutrients and drugs, immunomodulation, and pathogen defense by inhabiting the gastrointestinal tract (GIT). The role of the GM in the gut-brain axis (GBA) has been documented for different regulatory mechanisms and associated pathways and it shows different behaviors with individualized bacteria. In addition, the GM are known as susceptibility factor for neurological disorders in the central nervous system (CNS), regulating disease progression and being amenable to intervention. Bidirectional transmission between the brain and the GM occurs in the GBA, implying that it performs a significant role in neurocrine, endocrine, and immune-mediated signaling pathways. The GM regulates multiple neurological disorders by supplementing them with prebiotics, probiotics, postbiotics, synbiotics, fecal transplantations, and/or antibiotics. A well-balanced diet is critically important for establishing healthy GM, which can alter the enteric nervous system (ENS) and regulate multiple neurological disorders. Here, we have discussed the function of the GM in the GBA from the gut to the brain and the brain to the gut, the pathways associated with neurology that interacts with the GM, and the various neurological disorders associated with the GM. Furthermore, we have highlighted the recent advances and future prospects of the GBA, which may require addressing research concerns about GM and associated neurological disorders.

6.
Int J Yoga ; 16(3): 171-179, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38463653

RESUMO

The optic nerve comprises approximately 1.2 million axons of retinal ganglion cells and is vulnerable to degeneration due to a myriad of causes. While traditional treatments have been the cornerstone of ocular care, emerging evidence highlights the benefits of integrative approaches, which can be used as an adjunct in the management of optic neuropathy. Yoga is a mind-body energy medicine encompasses physical postures, breath control, and meditation. Currently, it has gained attention for its holistic effects on well-being, by promoting health, preventing onset of diseases, adjunct in disease management, and for its rehabilitative potential. In addition, the underlying mechanisms through which yoga exerts its therapeutic influence, evaluates clinical outcomes, and explores potential synergistic effects with conventional treatments remain largely unexplored. Neuroprotective mechanisms of yoga, such as enhancing retinal ganglion cell function, reducing oxidative stress, coupled with its ability to modulate inflammatory processes and improve circulation, contribute to its potential benefits in visual health. Analysis of clinical studies reveals promising outcomes, including improvements in visual acuity, visual fields, quality of life, and functional outcomes in individuals with optic neuropathy and ocular manifestations who undergo yoga intervention (especially dhyaan) with awareness of breath. Furthermore, the integration of yoga with conventional treatments and complementary modalities unveils the possibilities of multidisciplinary approaches in ocular care that need evaluation. By unraveling the role of yoga intervention in ocular health, this review provides valuable insights for clinicians and researchers, fostering a deeper understanding of the mind-body connection and paving the way for enhanced visual health outcomes. Embracing yoga as an adjunctive therapy may has the potential to revolutionize the management of optic neuropathy and ocular manifestations, offering individuals a holistic approach to optimize visual well-being, reduce comorbid depression and caregiver burden, and improve overall quality of life.

7.
Microb Pathog ; 173(Pt B): 105885, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36403711

RESUMO

Stress adaptation and virulence of various bacterial pathogens require stringent response pathways involving guanosine pentaphosphate and inorganic polyphosphate (PolyP). In M. tuberculosis, intracellular PolyP levels are maintained by the activities of polyphosphate kinase (PPK-1, PPK-2) and exopolyphosphatases (PPX-1, PPX-2). We demonstrate that these exopolyphosphatases cumulatively contribute to biofilm formation and survival of M. tuberculosis in nutrient limiting, low oxygen growth conditions and in macrophages. Characterization of single (Δppx2) and double knock out strain (dkppx) of M. tuberculosis demonstrated that these exopolyphosphatases are essential for establishing infection in guinea pigs and mice. Transcriptional profiling revealed that relative to the parental strain the expression of genes belonging to DosR regulon were significantly reduced in mid-log phase cultures of dkppx strain. We also show that PolyP inhibited the autophosphorylation activities associated with DosT and DosS sensor kinases. Host RNA-seq analysis revealed that transcripts involved in various antimicrobial pathways such as apoptosis, autophagy, macrophage activation, calcium signalling, innate and T-cell response were differentially expressed in lung tissues of dkppx strain infected mice. Taken together, we demonstrate that enzymes involved in PolyP homeostasis play a critical role in physiology and virulence of M. tuberculosis. These enzymes are attractive targets for developing novel interventions that might be active against drug-sensitive and drug-resistant M. tuberculosis.


Assuntos
Mycobacterium tuberculosis , Tuberculose Resistente a Múltiplos Medicamentos , Animais , Cobaias , Camundongos , Mycobacterium tuberculosis/genética , Virulência , Macrófagos
8.
Heliyon ; 8(10): e11073, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36281370

RESUMO

Objective: The goal of this study was to determine the effects of mono-, bi-, and polytherapy anti-seizure medications (ASMs) in terms of seizure reduction and quality of life (QOL) in persons with epilepsy (PWE). Methods: A cross-sectional observational study was conducted. All PWE with age <75 years were recruited and further classified into two groups: responders and non-responders, based on the response of the ASMs to the treatments for reduced seizure frequency since the last one year. Other demographic and clinical data such as seizure frequency, type of seizures, age at onset of seizures, and information about ASMs with their daily doses were assessed for the descriptive analysis. The quality of life was assessed in randomly selected PWE (n = 100) using the quality of life in epilepsy inventory-31 (QOLIE-31) in adults. Results: With a total of 486 PWE, the median age (years) was comparable in both groups. Out of these the non-responders group was found to be significantly higher (77.8%) than the responders group (22.2%). In the responders group, the percentage of PWE who were on monotherapy was significantly higher (51.85 %) than those who were on polytherapy (17.59%), whereas in the non-responders group, 21.16% of PWE were on monotherapy and 44.86% were on polytherapy. The duration of epilepsy was similar in both groups, but the average seizure frequency was significantly higher in the non-responders. In QOL assessments, 43% of PWE were observed in the responders group, whereas 57% of PWE were found in the non-responders group. The overall comparative QOL scores were also significantly higher (p < 0.0001) in the responders group as compared to the non-responders group. Conclusion: Our findings revealed that those PWE who were on monotherapy showed better reduction in seizure frequency and improved QOL in responder groups as compared to non-responder groups.

9.
Sci Rep ; 12(1): 8744, 2022 05 24.
Artigo em Inglês | MEDLINE | ID: mdl-35610240

RESUMO

The role of RORγ as a transcription factor for Th17 cell differentiation and thereby regulation of IL-17 levels is well known. Increased RORγ expression along with IL-17A levels was observed in animal models, immune cells and BAL fluid of COPD patients. Increased IL-17A levels in severe COPD patients are positively correlated with decreased lung functions and increased severity symptoms and emphysema, supporting an urgency to develop novel therapies modulating IL-17 or RORγ for COPD treatment. We identified a potent RORγ inhibitor, PCCR-1 using hit to lead identification followed by extensive lead optimization by structure-activity relationship. PCCR-1 resulted in RORγ inhibition with a high degree of specificity in a biochemical assay, with > 300-fold selectivity over other isoforms of ROR. Our data suggest promising potency for IL-17A inhibition in human and canine PBMCs and mouse splenocytes with no significant impact on Th1 and Th2 cytokines. In vivo, PCCR-1 exhibited significant efficacy in the acute CS model with dose-dependent inhibition of the PD biomarkers that correlated well with the drug concentration in lung and BAL fluid, demonstrating an acceptable safety profile. This inhibitor effectively inhibited IL-17A release in whole blood and BALf samples from COPD patients. Overall, we identified a selective inhibitor of RORγ to pursue further development of novel scaffolds for COPD treatment.


Assuntos
Obstrução das Vias Respiratórias , Doença Pulmonar Obstrutiva Crônica , Enfisema Pulmonar , Obstrução das Vias Respiratórias/metabolismo , Animais , Cães , Humanos , Interleucina-17/metabolismo , Pulmão/metabolismo , Camundongos , Membro 3 do Grupo F da Subfamília 1 de Receptores Nucleares/metabolismo , Doença Pulmonar Obstrutiva Crônica/metabolismo , Enfisema Pulmonar/metabolismo , Células Th17
13.
Sci Rep ; 10(1): 15610, 2020 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-32958827

RESUMO

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

14.
J Biol Chem ; 294(28): 10819-10832, 2019 07 12.
Artigo em Inglês | MEDLINE | ID: mdl-31113860

RESUMO

Stringent response pathways involving inorganic polyphosphate (PolyP) play an essential role in bacterial stress adaptation and virulence. The intracellular levels of PolyP are modulated by the activities of polyphosphate kinase-1 (PPK1), polyphosphate kinase-2 (PPK2), and exopolyphosphatases (PPXs). The genome of Mycobacterium tuberculosis encodes two functional PPXs, and simultaneous deletion of ppx1 and ppx2 results in a defect in biofilm formation. We demonstrate here that these PPXs cumulatively contribute to the ability of M. tuberculosis to survive in nutrient-limiting, low-oxygen growth conditions and also in macrophages. Characterization of single (Δppx2) and double knockout (dkppx) strains of M. tuberculosis indicated that PPX-mediated PolyP degradation is essential for establishing bacterial infection in guinea pigs. RNA-Seq-based transcriptional profiling revealed that relative to the parental strain, the expression levels of DosR regulon-regulated dormancy genes were significantly reduced in the dkppx mutant strain. In concordance, we also provide evidence that PolyP inhibits the autophosphorylation activities associated with DosT and DosS sensor kinases. The results in this study uncover that enzymes involved in PolyP homeostasis play a critical role in M. tuberculosis physiology and virulence and are attractive targets for developing more effective therapeutic interventions.


Assuntos
Hidrolases Anidrido Ácido/metabolismo , Mycobacterium tuberculosis/fisiologia , Polifosfatos/metabolismo , Hidrolases Anidrido Ácido/genética , Animais , Antituberculosos/farmacologia , Proteínas de Bactérias/metabolismo , Feminino , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Cobaias , Viabilidade Microbiana/efeitos dos fármacos , Mycobacterium tuberculosis/metabolismo , Mycobacterium tuberculosis/patogenicidade , Fosfotransferases/genética , Fosfotransferases (Aceptor do Grupo Fosfato)/metabolismo , Fosfotransferases (Aceptor do Grupo Fosfato)/fisiologia , Virulência/efeitos dos fármacos
15.
Nucleic Acids Res ; 46(21): 11639-11655, 2018 11 30.
Artigo em Inglês | MEDLINE | ID: mdl-30329074

RESUMO

Toxin-antitoxin (TA) systems are involved in diverse physiological processes in prokaryotes, but their exact role in Mycobacterium tuberculosis (Mtb) virulence and in vivo stress adaptation has not been extensively studied. Here, we demonstrate that the VapBC11 TA module is essential for Mtb to establish infection in guinea pigs. RNA-sequencing revealed that overexpression of VapC11 toxin results in metabolic slowdown, suggesting that modulation of the growth rate is an essential strategy for in vivo survival. Interestingly, overexpression of VapC11 resulted in the upregulation of chromosomal TA genes, suggesting the existence of highly coordinated crosstalk among TA systems. In this study, we also present the crystal structure of the VapBC11 heterooctameric complex at 1.67 Å resolution. Binding kinetic studies suggest that the binding affinities of toxin-substrate and toxin-antitoxin interactions are comparable. We used a combination of structural studies, molecular docking, mutational analysis and in vitro ribonuclease assays to enhance our understanding of the mode of substrate recognition by the VapC11 toxin. Furthermore, we have also designed peptide-based inhibitors to target VapC11 ribonuclease activity. Taken together, we propose that the structure-guided design of inhibitors against in vivo essential ribonucleases might be a novel strategy to hasten clearance of intracellular Mtb.


Assuntos
Proteínas de Bactérias/metabolismo , Mycobacterium bovis/genética , Mycobacterium bovis/metabolismo , Sistemas Toxina-Antitoxina/genética , Animais , Proteínas de Bactérias/genética , Toxinas Bacterianas/metabolismo , Sítios de Ligação , Domínio Catalítico , Cristalografia por Raios X , Feminino , Cobaias , Cinética , Modelos Moleculares , Simulação de Acoplamento Molecular , Mycobacterium smegmatis/metabolismo , Mycobacterium tuberculosis/metabolismo , Ribonucleases/metabolismo
16.
J Infect Dis ; 217(11): 1809-1820, 2018 05 05.
Artigo em Inglês | MEDLINE | ID: mdl-29529224

RESUMO

Toxin-antitoxin (TA) systems are bicistronic genetic modules that are ubiquitously present in bacterial genomes. The Mycobacterium tuberculosis genome encodes 90 putative TA systems, and these are considered to be associated with maintenance of bacterial genomic stability or bacterial survival under unfavorable environmental conditions. The majority of these in M. tuberculosis have been annotated as belonging to the virulence-associated protein B and C (VapBC) family. However, their precise role in bacterial physiology has not been elucidated. Here, we functionally characterized VapC toxins from M. tuberculosis and show that overexpression of some homologs inhibits growth of Mycobacterium bovis bacillus Calmette-Guérin in a bacteriostatic manner. Expression profiling of messenger RNA revealed that these VapC toxins were differentially induced upon exposure of M. tuberculosis to stress conditions. We also unraveled that transcriptional cross-activation exists between TA systems in M. tuberculosis. This study provides the first evidence for the essentiality of VapBC3 and VapBC4 systems in M. tuberculosis virulence.


Assuntos
Antitoxinas/genética , Proteínas de Bactérias/genética , Toxinas Bacterianas/genética , Mycobacterium tuberculosis/genética , Sistemas Toxina-Antitoxina/genética , Virulência/genética , Regulação Bacteriana da Expressão Gênica/genética , Genoma Bacteriano/genética , RNA Mensageiro/genética
17.
Artigo em Inglês | MEDLINE | ID: mdl-28893784

RESUMO

New chemotherapeutic agents with novel mechanisms of action are urgently required to combat the challenge imposed by the emergence of drug-resistant mycobacteria. In this study, a phenotypic whole-cell screen identified 5-nitro-1,10-phenanthroline (5NP) as a lead compound. 5NP-resistant isolates harbored mutations that were mapped to fbiB and were also resistant to the bicyclic nitroimidazole PA-824. Mechanistic studies confirmed that 5NP is activated in an F420-dependent manner, resulting in the formation of 1,10-phenanthroline and 1,10-phenanthrolin-5-amine as major metabolites in bacteria. Interestingly, 5NP also killed naturally resistant intracellular bacteria by inducing autophagy in macrophages. Structure-activity relationship studies revealed the essentiality of the nitro group for in vitro activity, and an analog, 3-methyl-6-nitro-1,10-phenanthroline, that had improved in vitro activity and in vivo efficacy in mice compared with that of 5NP was designed. These findings demonstrate that, in addition to a direct mechanism of action against Mycobacterium tuberculosis, 5NP also modulates the host machinery to kill intracellular pathogens.


Assuntos
Antituberculosos/farmacologia , Autofagia/efeitos dos fármacos , Mycobacterium tuberculosis/efeitos dos fármacos , Fenantrolinas/farmacologia , Tuberculose Resistente a Múltiplos Medicamentos/tratamento farmacológico , Animais , Linhagem Celular Tumoral , Modelos Animais de Doenças , Escherichia coli/efeitos dos fármacos , Feminino , Humanos , Macrófagos/metabolismo , Macrófagos/microbiologia , Camundongos , Camundongos Endogâmicos BALB C , Testes de Sensibilidade Microbiana , Mycobacterium bovis/efeitos dos fármacos , Mycobacterium smegmatis/efeitos dos fármacos , Mycobacterium tuberculosis/genética , Mycobacterium tuberculosis/crescimento & desenvolvimento , Mycobacterium tuberculosis/isolamento & purificação , Nitroimidazóis/farmacologia , Relação Estrutura-Atividade , Células THP-1
18.
Sci Rep ; 6: 26900, 2016 06 09.
Artigo em Inglês | MEDLINE | ID: mdl-27279366

RESUMO

Inorganic polyphosphate (PolyP) plays an essential role in microbial stress adaptation, virulence and drug tolerance. The genome of Mycobacterium tuberculosis encodes for two polyphosphate kinases (PPK-1, Rv2984 and PPK-2, Rv3232c) and polyphosphatases (ppx-1, Rv0496 and ppx-2, Rv1026) for maintenance of intracellular PolyP levels. Microbial polyphosphate kinases constitute a molecular mechanism, whereby microorganisms utilize PolyP as phosphate donor for synthesis of ATP. In the present study we have constructed ppk-2 mutant strain of M. tuberculosis and demonstrate that PPK-2 enzyme contributes to its ability to cause disease in guinea pigs. We observed that ppk-2 mutant strain infected guinea pigs had significantly reduced bacterial loads and tissue pathology in comparison to wild type infected guinea pigs at later stages of infection. We also report that in comparison to the wild type strain, ppk-2 mutant strain was more tolerant to isoniazid and impaired for survival in THP-1 macrophages. In the present study we have standardized a luciferase based assay system to identify chemical scaffolds that are non-cytotoxic and inhibit M. tuberculosis PPK-2 enzyme. To the best of our knowledge this is the first study demonstrating feasibility of high throughput screening to obtain small molecule PPK-2 inhibitors.


Assuntos
Antituberculosos/farmacologia , Proteínas de Bactérias/antagonistas & inibidores , Mycobacterium tuberculosis/enzimologia , Fosfotransferases (Aceptor do Grupo Fosfato)/antagonistas & inibidores , Tuberculose Pulmonar/tratamento farmacológico , Animais , Animais não Endogâmicos , Carga Bacteriana , Proteínas de Bactérias/química , Avaliação Pré-Clínica de Medicamentos , Farmacorresistência Bacteriana , Feminino , Cobaias , Humanos , Pulmão/microbiologia , Pulmão/patologia , Mycobacterium tuberculosis/crescimento & desenvolvimento , Mycobacterium tuberculosis/patogenicidade , Fosfotransferases (Aceptor do Grupo Fosfato)/química , Células THP-1 , Tuberculose Pulmonar/microbiologia , Virulência
20.
Nat Commun ; 6: 6059, 2015 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-25608501

RESUMO

Toxin-antitoxin (TA) systems are highly conserved in members of the Mycobacterium tuberculosis (Mtb) complex and have been proposed to play an important role in physiology and virulence. Nine of these TA systems belong to the mazEF family, encoding the intracellular MazF toxin and its antitoxin, MazE. By overexpressing each of the nine putative MazF homologues in Mycobacterium bovis BCG, here we show that Rv1102c (MazF3), Rv1991c (MazF6) and Rv2801c (MazF9) induce bacteriostasis. The construction of various single-, double- and triple-mutant Mtb strains reveals that these MazF ribonucleases contribute synergistically to the ability of Mtb to adapt to conditions such as oxidative stress, nutrient depletion and drug exposure. Moreover, guinea pigs infected with the triple-mutant strain exhibits significantly reduced bacterial loads and pathological damage in infected tissues in comparison with parental strain-infected guinea pigs. The present study highlights the importance of MazF ribonucleases in Mtb stress adaptation, drug tolerance and virulence.


Assuntos
Proteínas de Bactérias/fisiologia , Endorribonucleases/fisiologia , Mycobacterium tuberculosis/metabolismo , Animais , Antitoxinas/química , Antituberculosos/química , Proteínas de Bactérias/metabolismo , Modelos Animais de Doenças , Progressão da Doença , Farmacorresistência Bacteriana , Tolerância a Medicamentos , Endorribonucleases/metabolismo , Feminino , Genoma Bacteriano , Cobaias , Cinética , Macrófagos/microbiologia , Mutação , Mycobacterium bovis/metabolismo , Estresse Oxidativo , Reação em Cadeia da Polimerase , Mapeamento de Interação de Proteínas , Ribonucleases/genética , Virulência
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