RESUMO
The protein translocase of the mitochondrial inner membrane in Trypanosoma brucei, TbTIM17, forms a modular complex in association with several other trypanosome-specific proteins. To identify transiently interacting proximal partner(s) of TbTim17, we used Biotinylation Identification (BioID) by expressing a modified biotin ligase-TbTim17 (BirA∗-TbTim17) fusion protein in T. brucei. BirA∗-TbTim17 was targeted to mitochondria and assembled in the TbTIM complex. In the presence of biotin, BirA∗-TbTim17 biotinylated several mitochondrial proteins. Interestingly, TbHsp84/TbTRAP1, a mitochondrial Hsp90 homolog, was identified as the highest enriched biotinylated proteins. We validated that interaction and colocalization of TbTim17 and TbHsp84 in T. brucei mitochondria by coimmunoprecipitation analysis and confocal microscopy, respectively. TbTim17 association with TbTRAP1 increased several folds during denaturation/renaturation of mitochondrial proteins in vitro, suggesting TbTRAP1 acts as a chaperone for TbTim17 refolding. We demonstrated that knockdown of TbTRAP1 reduced cell growth and decreased the levels of the TbTIM17, TbTim62, and mitochondrial (m)Hsp70 complexes. However, ATPase, VDAC, and Atom69 complexes were minimally affected. Additionally, the steady state levels of TbTim17, TbTim62, and mHsp70 were reduced significantly, but Atom69, ATPase ß, and RBP16 were mostly unaltered due to TbTRAP1 knockdown. Quantitative proteomics analysis also showed significant reduction of TbTim62 along with a few other mitochondrial proteins due to TbTRAP1 knockdown. Finally, TbTRAP1 depletion did not hamper the import of the ectopically expressed TbTim17-2xMyc into mitochondria but reduced its assembly into the TbTIM17 complex, indicating TbTRAP1 is critical for assembly of TbTim17. This is the first report showing the role of TRAP1 in the TIM complex assembly in eukaryotes.
Assuntos
Proteínas de Protozoários , Trypanosoma brucei brucei , Adenosina Trifosfatases/metabolismo , Biotina/metabolismo , Biotinilação , Proteínas Mitocondriais/genética , Proteínas Mitocondriais/metabolismo , Proteínas de Protozoários/metabolismo , Trypanosoma brucei brucei/metabolismoRESUMO
The dopamine transporter (DAT) is essential for the reuptake of the released neurotransmitter dopamine (DA) in the brain. Psychostimulants, methamphetamine and cocaine, have been reported to induce the formation of DAT multimeric complexes in vivo and in vitro. The interpretation of DAT multimer function has been primarily in the context of compounds that induce structural and functional modifications of the DAT, complicating the understanding of the significance of DAT multimers. To examine multimerization in the absence of DAT ligands as well as in their presence, we developed a novel, optogenetic fusion chimera of cryptochrome 2 and DAT with an mCherry fluorescent reporter (Cry2-DAT). Using blue light to induce Cry2-DAT multimeric protein complex formation, we were able to simultaneously test the functional contributions of DAT multimerization in the absence or presence of substrates or inhibitors with high spatiotemporal precision. We found that blue light-stimulated Cry2-DAT multimers significantly increased IDT307 uptake and MFZ 9-18 binding in the absence of ligands as well as after methamphetamine and nomifensine treatment. Blue light-induced Cry2-DAT multimerization increased colocalization with recycling endosomal marker Rab11 and had decreased presence in Rab5-positive early endosomes and Rab7-positive late endosomes. Our data suggest that the increased uptake and binding results from induced and rapid trafficking of DAT multimers to the plasma membrane. Our data suggest that DAT multimers may function to help maintain DA homeostasis.
Assuntos
Membrana Celular/metabolismo , Proteínas da Membrana Plasmática de Transporte de Dopamina/metabolismo , Dopamina/metabolismo , Animais , Transporte Biológico , Membrana Celular/genética , Proteínas da Membrana Plasmática de Transporte de Dopamina/genética , Expressão Gênica , Células HEK293 , Humanos , Neurônios/metabolismo , Optogenética , Multimerização ProteicaRESUMO
COVID-19, caused by the highly transmissible severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), has rapidly spread and become a pandemic since its outbreak in 2019. We have previously discovered that aloperine is a new privileged scaffold that can be modified to become a specific antiviral compound with markedly improved potency against different viruses, such as the influenza virus. In this study, we have identified a collection of aloperine derivatives that can inhibit the entry of SARS-CoV-2 into host cells. Compound 5 is the most potent tested aloperine derivative that inhibited the entry of SARS-CoV-2 (D614G variant) spike protein-pseudotyped virus with an IC50 of 0.5 µM. The compound was also active against several other SARS-CoV-2 variants including Delta and Omicron. Results of a confocal microscopy study suggest that compound 5 inhibited the viral entry before fusion to the cell or endosomal membrane. The results are consistent with the notion that aloperine is a privileged scaffold that can be used to develop potent anti-SARS-CoV-2 entry inhibitors.
Assuntos
Tratamento Farmacológico da COVID-19 , Inibidores da Fusão de HIV , Quinolizidinas , Humanos , Pandemias , Quinolizidinas/farmacologia , SARS-CoV-2 , Internalização do VírusRESUMO
The duration and strength of the dopaminergic signal are regulated by the dopamine transporter (DAT). Drug addiction and neurodegenerative and neuropsychiatric diseases have all been associated with altered DAT activity. The membrane localization and the activity of DAT are regulated by a number of intracellular proteins. α-Synuclein, a protein partner of DAT, is implicated in neurodegenerative disease and drug addiction. Little is known about the regulatory mechanisms of the interaction between DAT and α-synuclein, the cellular location of this interaction, and the functional consequences of this interaction on the basal, amphetamine-induced DAT-mediated dopamine efflux, and membrane microdomain distribution of the transporter. Here, we found that the majority of DAT·α-synuclein protein complexes are found at the plasma membrane of dopaminergic neurons or mammalian cells and that the amphetamine-mediated increase in DAT activity enhances the association of these proteins at the plasma membrane. Further examination of the interaction of DAT and α-synuclein revealed a transient interaction between these two proteins at the plasma membrane. Additionally, we found DAT-induced membrane depolarization enhances plasma membrane localization of α-synuclein, which in turn increases dopamine efflux and enhances DAT localization in cholesterol-rich membrane microdomains.
Assuntos
Proteínas da Membrana Plasmática de Transporte de Dopamina/metabolismo , Dopamina/metabolismo , alfa-Sinucleína/metabolismo , Anfetamina/metabolismo , Animais , Biotinilação , Encéfalo/metabolismo , Células CHO , Linhagem Celular , Membrana Celular/metabolismo , Cricetinae , Cricetulus , Neurônios Dopaminérgicos/metabolismo , Transferência Ressonante de Energia de Fluorescência , Humanos , Microdomínios da Membrana/metabolismo , Doenças Neurodegenerativas/metabolismo , Transmissão Sináptica , Sinucleínas/metabolismoRESUMO
BACKGROUND: Escherichia coli-bearing Dr-adhesins (Dr+ E. coli) cause chronic pyelonephritis in pregnant women and animal models. This chronic renal infection correlates with the capacity of bacteria to invade epithelial cells expressing CD55. The mechanism of infection remains unknown. METHODS: CD55 amino acids in the vicinity of binding pocket-Ser155 for Dr-adhesin were mutated to alanine and subjected to temporal gentamicin-invasion/gentamicin-survival assay in Chinese hamster ovary cells. CD55/microtubule (MT) responses were studied using confocal/electron microscopy, and 3-dimensional structure analysis. RESULTS: Mutant analysis revealed that complement-protective CD55-Ser165 and CD55-Phe154 epitopes control E. coli invasion by coregulating CD55-MT complex expression. Single-point CD55 mutations changed E. coli to either a minimally invasive (Ser165Ala) or a hypervirulent pathogen (Phe154Ala). Thus, single amino acid modifications with no impact on CD55 structure and bacterial attachment can have a profound impact on E. coli virulence. While CD55-Ser165Ala decreased E. coli invasion and led to dormant intracellular persistence, intracellular E. coli in CD55-Phe154Ala developed elongated forms (multiplying within vacuoles), upregulated CD55-MT complexes, acquired CD55 coat, and escaped phagolysosomal fusion. CONCLUSIONS: E. coli target complement-protective CD55 epitopes for invasion and exploit CD55-MT complexes to escape phagolysosomal fusion, leading to a nondestructive parasitism that allows bacteria to persist intracellularly.
Assuntos
Antígenos CD55/metabolismo , Proteínas do Sistema Complemento/imunologia , Endocitose , Microtúbulos/metabolismo , Escherichia coli Uropatogênica/imunologia , Escherichia coli Uropatogênica/fisiologia , Adesinas de Escherichia coli/imunologia , Adesinas de Escherichia coli/metabolismo , Animais , Antígenos CD55/genética , Células CHO , Cricetulus , Microscopia Confocal , Microscopia Eletrônica , Proteínas Mutantes/genética , Proteínas Mutantes/metabolismo , Conformação ProteicaRESUMO
[This corrects the article DOI: 10.1371/journal.pone.0246393.].
RESUMO
The parasitic protozoan Leishmania invades mammalian macrophages to establish infection. We reported previously that Leishmania manipulates the expression of several non-coding RNA genes (e.g. Alu RNA, B1 RNA, and signal recognition particle RNA) in macrophages to favor the establishment of their infection in the phagolysosomes of these cells (Ueda, Y., and Chaudhuri, G. (2000) J. Biol. Chem. 275, 19428-19432; Misra, S., Tripathi, M. K., and Chaudhuri, G. (2005) J. Biol. Chem. 280, 29364-29373). We report here the mechanism of this down-regulation. We found that the non-coding RNA (ncRNA) genes that are repressed by Leishmania infection in macrophages contain a "B-box" in their promoters and thus require the polymerase III transcription factor TFIIIC for their expression. We also found that Leishmania promastigotes through their surface protease (leishmanolysin or gp63) activate the thrombin receptor PAR1 in the macrophages. This activation of PAR1 raised the cytosolic concentration of Ca(2+) into the micromolar range, thereby activating the Ca(2+)-dependent protease µ-calpain. µ-Calpain then degraded TFIIIC110 to inhibit the expression of the selected ncRNA genes. Avirulent stocks of Leishmania not expressing surface gp63 failed to down-regulate ncRNAs in the exposed macrophages. Inhibition of PAR1 or calpain 1 in macrophages made them resistant to Leishmania infection. These data suggest that macrophage PAR1 and calpain 1 are potential drug targets against leishmaniasis.
Assuntos
Regulação para Baixo , Leishmania major/metabolismo , Leishmaniose Cutânea/metabolismo , Macrófagos/metabolismo , RNA Polimerase III/metabolismo , RNA não Traduzido/biossíntese , Animais , Cálcio/metabolismo , Calpaína/genética , Calpaína/metabolismo , Linhagem Celular Tumoral , Humanos , Leishmania major/genética , Leishmania major/patogenicidade , Leishmaniose Cutânea/genética , Macrófagos/parasitologia , Metaloendopeptidases/genética , Metaloendopeptidases/metabolismo , Camundongos , RNA Polimerase III/genética , RNA não Traduzido/genética , Receptor PAR-1/genética , Receptor PAR-1/metabolismo , Fatores de Transcrição TFIII/genética , Fatores de Transcrição TFIII/metabolismoRESUMO
The protozoan parasite, Trypanosoma cruzi, causes severe morbidity and mortality in afflicted individuals. Approximately 30% of T. cruzi infected individuals present with cardiac pathology. The invasive forms of the parasite are carried in the vascular system to infect other cells of the body. During transportation, the molecular mechanisms by which the parasite signals and interact with host endothelial cells (EC) especially heart endothelium is currently unknown. The parasite increases host thrombospondin-1 (TSP1) expression and activates the Wnt/ß-catenin and hippo signaling pathways during the early phase of infection. The links between TSP1 and activation of the signaling pathways and their impact on parasite infectivity during the early phase of infection remain unknown. To elucidate the significance of TSP1 function in YAP/ß-catenin colocalization and how they impact parasite infectivity during the early phase of infection, we challenged mouse heart endothelial cells (MHEC) from wild type (WT) and TSP1 knockout mice with T. cruzi and evaluated Wnt signaling, YAP/ß-catenin crosstalk, and how they affect parasite infection. We found that in the absence of TSP1, the parasite induced the expression of Wnt-5a to a maximum at 2 h (1.73±0.13), P< 0.001 and enhanced the level of phosphorylated glycogen synthase kinase 3ß at the same time point (2.99±0.24), P<0.001. In WT MHEC, the levels of Wnt-5a were toned down and the level of p-GSK-3ß was lowest at 2 h (0.47±0.06), P< 0.01 compared to uninfected control. This was accompanied by a continuous significant increase in the nuclear colocalization of ß-catenin/YAP in TSP1 KO MHEC with a maximum Pearson correlation coefficient of (0.67±0.02), P< 0.05 at 6 h. In WT MHEC, the nuclear colocalization of ß-catenin/YAP remained steady and showed a reduction at 6 h (0.29±0.007), P< 0.05. These results indicate that TSP1 plays an important role in regulating ß-catenin/YAP colocalization during the early phase of T. cruzi infection. Importantly, dysregulation of this crosstalk by pre-incubation of WT MHEC with a ß-catenin inhibitor, endo-IWR 1, dramatically reduced the level of infection of WT MHEC. Parasite infectivity of inhibitor treated WT MHEC was similar to the level of infection of TSP1 KO MHEC. These results indicate that the ß-catenin pathway induced by the parasite and regulated by TSP1 during the early phase of T. cruzi infection is an important potential therapeutic target, which can be explored for the prophylactic prevention of T. cruzi infection.
Assuntos
Doença de Chagas/patologia , Via de Sinalização Hippo/fisiologia , Trombospondina 1/metabolismo , Via de Sinalização Wnt/fisiologia , Proteínas de Sinalização YAP/metabolismo , beta Catenina/metabolismo , Transporte Ativo do Núcleo Celular/fisiologia , Animais , Células Endoteliais/parasitologia , Endotélio/citologia , Endotélio/parasitologia , Glicogênio Sintase Quinase 3 beta/metabolismo , Coração/parasitologia , Camundongos , Camundongos Knockout , Ratos , Trombospondina 1/genética , Trypanosoma cruzi/metabolismo , Proteína Wnt-5a/metabolismo , beta Catenina/antagonistas & inibidoresRESUMO
Leishmania is a group of parasitic protozoa that infect blood and tissue phagocytes including macrophages. We hypothesize that Leishmania is capable of establishing infection inside the macrophages because (a) they infect a subpopulation of macrophages; and (b) they "renovate" the macrophages before the establishment of infection. We found that only alternatively activated polarized M2 macrophages support Leishmania growth. Exposure of M2 macrophages to Leishmania promastigotes represses several selected RNA polymerase III (PolIII)-transcribed non-coding RNA (ncRNA) genes including those of 7SL RNA, vault RNA, and B2 RNA which have B-box element at their promoters. The B-box-binding transcription factor TFIIIC110 is down-regulated in Leishmania-exposed macrophages. Both the surface protease gp63 and the surface glycolipid LPG are required for the down-regulation of the ncRNAs in the M2 macrophages. We conclude that Leishmania surface gp63 collaborates with LPG to down-regulate TFIIIC110 in M2 macrophages to repress B-box containing ncRNA gene promoters.
Assuntos
Polaridade Celular , Leishmania/fisiologia , Macrófagos/metabolismo , Regiões Promotoras Genéticas , RNA não Traduzido/genética , Elementos Reguladores de Transcrição , Animais , Sequência de Bases , Polaridade Celular/fisiologia , Células Cultivadas , Regulação para Baixo/fisiologia , Regulação da Expressão Gênica , Humanos , Ativação de Macrófagos/genética , Ativação de Macrófagos/fisiologia , Macrófagos/fisiologia , Camundongos , Dados de Sequência Molecular , Regiões Promotoras Genéticas/genética , Regiões Promotoras Genéticas/fisiologia , RNA Citoplasmático Pequeno/química , RNA Citoplasmático Pequeno/genética , Elementos Reguladores de Transcrição/fisiologia , Partícula de Reconhecimento de Sinal/química , Partícula de Reconhecimento de Sinal/genética , Células U937RESUMO
Evidence link bacterial enterotoxins to apparent crypt-cell like cells (CCLCs), and Alpha Defensin 5 (DEFA5) expansion in the colonic mucosa of Crohn's colitis disease (CC) patients. These areas of ectopic ileal metaplasia, positive for Paneth cell (PC) markers are consistent with diagnosis of CC. Retrospectively, we: 1. Identified 21 patients with indeterminate colitis (IC) between 2000-2007 and were reevaluation their final clinical diagnosis in 2014 after a followed-up for mean 8.7±3.7 (range, 4-14) years. Their initial biopsies were analyzed by DEFA5 bioassay. 2. Differentiated ulcer-associated cell lineage (UACL) analysis by immunohistochemistry (IHC) of the CC patients, stained for Mucin 6 (MUC6) and DEFA5. 3. Treated human immortalized colonic epithelial cells (NCM460) and colonoids with pure DEFA5 on the secretion of signatures after 24hr. The control colonoids were not treated. 4. Treated colonoids with/without enterotoxins for 14 days and the spent medium were collected and determined by quantitative expression of DEFA5, CCLCs and other biologic signatures. The experiments were repeated twice. Three statistical methods were used: (i) Univariate analysis; (ii) LASSO; and (iii) Elastic net. DEFA5 bioassay discriminated CC and ulcerative colitis (UC) in a cohort of IC patients with accuracy. A fit logistic model with group CC and UC as the outcome and the DEFA5 as independent variable differentiator with a positive predictive value of 96 percent. IHC staining of CC for MUC6 and DEFA5 stained in different locations indicating that DEFA5 is not co-expressed in UACL and is therefore NOT the genesis of CC, rather a secretagogue for specific signature(s) that underlie the distinct crypt pathobiology of CC. Notably, we observed expansion of signatures after DEFA5 treatment on NCM460 and colonoids cells expressed at different times, intervals, and intensity. These factors are key stem cell niche regulators leading to DEFA5 secreting CCLCs differentiation 'the colonic ectopy ileal metaplasia formation' conspicuously of pathogenic importance in CC.
Assuntos
Colite Ulcerativa/metabolismo , Colo/citologia , Doença de Crohn/metabolismo , Enterotoxinas/farmacologia , Organoides/citologia , alfa-Defensinas/metabolismo , Idoso , Linhagem da Célula , Células Cultivadas , Colite Ulcerativa/microbiologia , Colite Ulcerativa/patologia , Colo/efeitos dos fármacos , Colo/metabolismo , Doença de Crohn/microbiologia , Doença de Crohn/patologia , Células Epiteliais/citologia , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/metabolismo , Feminino , Humanos , Modelos Logísticos , Masculino , Mucina-6/metabolismo , Técnicas de Cultura de Órgãos , Organoides/efeitos dos fármacos , Organoides/metabolismo , Proteômica , Estudos RetrospectivosRESUMO
Fetuin-A is a serum glycoprotein synthesized and secreted into blood by the liver and whose main physiological function is the inhibition of ectopic calcification. However, a number of studies have demonstrated that it is a multifunctional protein. For example, endocytic uptake of fetuin-A by tumor cells resulting in rapid cellular adhesion and spreading has been reported. The precise uptake mechanism, however, has been elusive. The present studies were done to determine whether Toll-like receptor-4 (TLR4), which has been previously shown to be a receptor for fetuin-A and is commonly expressed in immune cells, could take part in the rapid uptake (< 3 min) of fetuin-A by tumor cells. Rapid uptake of fetuin-A was inhibited by the specific TLR4 inhibitor CLI-095 and also attenuated in TLR4 knockdown prostate tumor cells. Inhibition of TLR4 by CLI-095 also attenuated the rapid adhesion of tumor cells as well as invasion through a bed of Matrigel. The data suggest mechanisms by which TLR4 modulates the adhesion and growth of tumor cells.
Assuntos
Receptor 4 Toll-Like/metabolismo , alfa-2-Glicoproteína-HS/metabolismo , Adesão Celular , Linhagem Celular Tumoral , Endocitose , HumanosRESUMO
We reported previously that reduction in beta-arrestin 1 (ß-AR 1) protein levels in peripheral blood mononuclear leukocytes (PBMC) significantly correlated with the severity of depressive symptoms in reproductive women. In this pilot study, we used ß-AR 1 protein levels in PBMC as a marker for developing depressive symptoms and the Hamilton Depression Rating Scale (HAM-D) scores to assess potential mood-related side effects of oral contraceptive use for routine birth control among women. We evaluated 29 women in this study. We enrolled the participants in three groups: Estrogen-progestin combination-oral contraceptives (COC, n = 10), progestin-only contraceptives (POC, n = 12), and non-hormonal or no contraceptives (NC, n = 7). We determined the ß-AR 1 protein levels in PBMCs by enzyme-linked immunosorbent assay (ELISA). We found that women in the POC group had significantly higher HAM-D scores compared to those in the COC (p < 0.0004) and NC (p < 0.004). The levels of ß-AR 1 protein were significantly attenuated in women in the POC group compared to women in the NC group (p = 0.03). Our findings suggest that the use of POC is a potential risk factor for developing depressive symptoms.
Assuntos
Biomarcadores/sangue , Anticoncepção/efeitos adversos , Anticoncepcionais Orais/efeitos adversos , Transtorno Depressivo/etiologia , Leucócitos Mononucleares/química , Progestinas/efeitos adversos , beta-Arrestina 1/sangue , Adolescente , Adulto , Feminino , Humanos , Projetos Piloto , Fatores de Risco , Tennessee , Adulto JovemRESUMO
The mechanisms by which exosomes (nano-vesicular messengers of cells) are taken up by recipient cells are poorly understood. We hypothesized that histones associated with these nanoparticles are the ligands which facilitate their interaction with cell surface syndecan-4 (SDC4) to mediate their uptake. We show that the incubation with fetuin-A (exosome-associated proteins) and histones mediates the uptake of exosomes that are normally not endocytosed. Similarly, hydroxyapatite-nanoparticles incubated with fetuin-A and histones (FNH) are internalized by tumor cells, while nanoparticles incubated with fetuin-A alone (FN) are not. The uptake of exosomes and FNH, both of which move to the perinuclear region of the cell, is attenuated in SDC4-knockdown cells. Data show that FNH can compete with exosomes for uptake and that both use SDC4 as uptake receptors.
Assuntos
Durapatita/metabolismo , Exossomos/metabolismo , Histonas/metabolismo , Nanopartículas/química , Sindecana-4/metabolismo , Linhagem Celular Tumoral , Membrana Celular/metabolismo , Durapatita/química , Endocitose , Espaço Extracelular/metabolismo , Humanos , Ligantes , Microscopia Confocal , Neoplasias/metabolismo , Neoplasias/patologia , Células PC-3 , Interferência de RNA , Sindecana-4/genética , alfa-2-Glicoproteína-HS/genética , alfa-2-Glicoproteína-HS/metabolismoRESUMO
Spoligotyping was performed on 540 Mycobacterium tuberculosis isolates in order to evaluate the genetic biodiversity of tubercle bacilli in India. One hundred and forty seven patterns were unique and 393 were grouped in 48 clusters. Comparison with an international spoligotype database showed that the most predominant clades among tuberculosis (TB) isolates were Central Asian (CAS) and East-African Indian (EAI) with shared-types (ST) ST26 and ST11 alone being responsible for 34% of all TB cases. Twenty one (3.8%) isolates belonged to the Beijing genotype. Marked variations were observed among circulating strains, STs belonging to CAS family predominated in the North, whereas the EAI family was more common in the Southern India. TB in India is predominantly caused by strains belonging to the principal genetic group 1 (PGG1), suggesting that most of the TB burden in India may be traced to ancestral clones of the tubercle bacilli. This study gives an insight into the global M. tuberculosis genetic biodiversity in India, the predominant spoligotypes and their impact on disease transmission.
Assuntos
Biodiversidade , Variação Genética , Mycobacterium tuberculosis/genética , Mycobacterium tuberculosis/isolamento & purificação , Tuberculose Pulmonar/microbiologia , Técnicas de Tipagem Bacteriana , Geografia , Humanos , Índia , Mycobacterium tuberculosis/classificaçãoRESUMO
Microscopy is the mainstay of laboratory diagnosis of tuberculosis especially in resource poor countries. The World Health Organization has also recommended microscopy as the mainstay of diagnosis for directly observed treatment, short course. Using DNA extracts from Ziehl-Neelsen (ZN)-stained sputum smears, a single-tube nested polymerase chain reaction was optimized to confirm Mycobacterium tuberculosis complex and detect rifampin (RIF) resistance by sequencing, using a combination of novel (rpoB47 and rpoB158) and previously described (rpoB105 and rpoB293) primers. Carryover DNA was strictly monitored using several negative controls, and inhibition was ruled out by spiked controls. No such target was detected from negative controls and purified genomic DNA from other nontubercular mycobacteria. Resistance could be detected in 91.1% (51/56) slides. The results obtained were concordant with the 1% proportion method and DNA sequencing performed on culture isolates. Our results demonstrate that the method is suitable for rapid detection of susceptibility to RIF in acid-fast bacillus-positive ZN-stained slides obtained from patients suspected of harboring drug-resistant M. tuberculosis.
Assuntos
Antituberculosos/farmacologia , Proteínas de Bactérias/genética , Mycobacterium tuberculosis/efeitos dos fármacos , Reação em Cadeia da Polimerase/métodos , Rifampina/farmacologia , Escarro/microbiologia , Tuberculose Resistente a Múltiplos Medicamentos/genética , DNA Bacteriano/análise , RNA Polimerases Dirigidas por DNA , Humanos , Técnicas Microbiológicas/métodos , Mycobacterium tuberculosis/classificação , Mycobacterium tuberculosis/genética , Sensibilidade e Especificidade , Tuberculose Resistente a Múltiplos Medicamentos/diagnósticoRESUMO
Spoligotyping was applied to old (5-11 years) Ziehl-Neelsen (ZN)-stained smears for strain identification and differentiation and to predict the utility of the technique in epidemiological studies. Among 57 DNA samples extracted from ZN slides lying stored at room temperature, 93% (53) amplification was achieved for mpt64 gene. Spoligopatterns were generated from 77.7% (41/53) DNA samples, whereas negative controls did not yield any spoligopatterns. All slides with 2+ (n=20) and 3+ (n=13) positivity while 42% (11/26) of slides with low positivity (< or 1+) showed a good signal and a reproducible pattern. This technique may have application in identification of spoligotypes in control programme implemented areas remote from research laboratory and would also increase our knowledge about the clonal structure of Mycobacterium tuberculosis in the population, when applied to old samples in different locations.
Assuntos
DNA Bacteriano/genética , Mycobacterium tuberculosis/classificação , Reação em Cadeia da Polimerase/métodos , Tuberculose/metabolismo , Antígenos de Bactérias/química , Antígenos de Bactérias/genética , DNA Bacteriano/química , Feminino , Humanos , Masculino , Mycobacterium tuberculosis/genética , Mycobacterium tuberculosis/isolamento & purificação , Reprodutibilidade dos Testes , Estudos Retrospectivos , Escarro/microbiologiaRESUMO
Cocaine exposure alters gene expression in the brain via methylation and acetylation of histones along with methylation of DNA. Recently, poly (ADP-ribose) polymerase-1 (PARP-1) catalyzed PARylation has been reported as an important regulator of cocaine-mediated gene expression. In this study, we report that the cellular microRNA "miR-125b" plays a key role for cocaine-induced PARP-1 expression. Acute and chronic cocaine exposure resulted in the downregulation of miR-125b concurrent with upregulation of PARP-1 in dopaminergic neuronal cells and nucleus accumbens (NAc) of mice but not in the medial prefrontal cortex (PFC) or ventral tegmental area (VTA). In silico analysis predicted a binding site of miR-125b in a conserved 3'-untranslated region (3'UTR) of the PARP-1 mRNA. Knockdown and overexpression studies showed that miR-125b levels negatively correlate with PARP-1 protein expression. Luciferase reporter assay using a vector containing the 3'UTR of PARP-1 mRNA confirmed regulation of PARP-1 by miR-125b. Specific nucleotide mutations within the binding site abrogated miR-125b's regulatory effect on PARP-1 3'UTR. Finally, we established that downregulation of miR-125b and concurrent upregulation of PARP-1 is dependent on binding of cocaine to the dopamine transporter (DAT). Collectively, these results identify miR-125b as a post-transcriptional regulator of PARP-1 expression and establish a novel mechanism underlying the molecular effects of cocaine action.
Assuntos
Encéfalo/efeitos dos fármacos , Cocaína/farmacologia , Inibidores da Captação de Dopamina/farmacologia , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , MicroRNAs/metabolismo , Poli(ADP-Ribose) Polimerase-1/metabolismo , Animais , Anexina A5/metabolismo , Apoptose/efeitos dos fármacos , Apoptose/fisiologia , Encéfalo/metabolismo , Bovinos , Linhagem Celular Tumoral , Proteínas da Membrana Plasmática de Transporte de Dopamina/genética , Proteínas da Membrana Plasmática de Transporte de Dopamina/metabolismo , Neurônios Dopaminérgicos/efeitos dos fármacos , Neurônios Dopaminérgicos/metabolismo , Ativação Enzimática/efeitos dos fármacos , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Neuroblastoma/patologia , Ligação Proteica/efeitos dos fármacos , Ligação Proteica/genética , Ratos , Tirosina 3-Mono-Oxigenase/metabolismoRESUMO
Decreased energy production and increased oxidative stress are considered to be major contributors to aging and aging-associated pathologies. The role of mitochondrial calcium homeostasis has also been highlighted as an important factor affecting different pathological conditions. Here, we present evidence that loss of a small mitochondrial protein Fus1 that maintains mitochondrial homeostasis results in premature aging, aging-associated pathologies, and decreased survival. We showed that Fus1KO mice develop multiple early aging signs including lordokyphosis, lack of vigor, inability to accumulate fat, reduced ability to tolerate stress, and premature death. Other prominent pathological changes included low sperm counts, compromised ability of adult stem cells to repopulate tissues, and chronic inflammation. At the molecular level, we demonstrated that mitochondria of Fus1 KO cells have low reserve respiratory capacity (the ability to produce extra energy during sudden energy demanding situations), and show significantly altered dynamics of cellular calcium response.Our recent studies on early hearing and memory loss in Fus1 KO mice combined with the new data presented here suggest that calcium and energy homeostasis controlled by Fus1 may be at the core of its aging-regulating activities. Thus, Fus1 protein and Fus1-dependent pathways and processes may represent new tools and targets for anti-aging strategies.
Assuntos
Senilidade Prematura/metabolismo , Envelhecimento/metabolismo , Cálcio/metabolismo , Metabolismo Energético/genética , Proteínas Supressoras de Tumor/metabolismo , Adiposidade/genética , Envelhecimento/genética , Senilidade Prematura/genética , Animais , Sinalização do Cálcio , Homeostase/genética , Inflamação/genética , Inflamação/metabolismo , Masculino , Camundongos , Camundongos Knockout , Espécies Reativas de Oxigênio/metabolismo , Contagem de Espermatozoides , Motilidade dos Espermatozoides/genética , Proteínas Supressoras de Tumor/genéticaRESUMO
Fever of unknown origin (FUO) poses a diagnostic challenge to the clinicians, with a differential diagnosis as varied as neoplastic and infectious diseases. In developing countries, the infectious causes are responsible for more cases of FUO, with tuberculosis as one of the main causes of classic FUO. Disseminated tuberculosis with negative pulmonary findings is a diagnostic problem. This study examines the diagnostic utility of the polymerase chain reaction (PCR) in samples of bone marrow aspirate in 85 patients presenting with diverse clinical symptoms. Using primers specific for Mycobacterium tuberculosis, tubercular etiology was detected in 33% of patients clinically suspected of tuberculosis while culture on Lowenstein-Jensen medium grew M. tuberculosis in only one patient (2.5%). None of these patients had been diagnosed by microscopy. Clinical improvement with ATT was observed in 85% of the patients with positive PCR. PCR demonstrated much higher sensitivity and specificity, thereby facilitating early therapeutic decisions for suspected extrapulmonary tuberculosis.
Assuntos
Medula Óssea/microbiologia , Mycobacterium tuberculosis/isolamento & purificação , Reação em Cadeia da Polimerase , Tuberculose/diagnóstico , Medula Óssea/patologia , DNA Bacteriano/genética , DNA Bacteriano/isolamento & purificação , Humanos , Mycobacterium tuberculosis/genética , Sensibilidade e EspecificidadeRESUMO
Glioblastomas (high-grade astrocytomas) are highly aggressive brain tumors with poor prognosis and limited treatment options. In the present studies, we have defined the role of fetuin-A, a liver-derived multifunctional serum protein, in the growth of an established glioblastoma cell line, LN229. We hereby demonstrate that these cells synthesize ectopic fetuin-A which supports their growth in culture in the absence of serum. We have demonstrated that a panel of tissue microarray (TMA) of glioblastomas also express ectopic fetuin-A. Knocking down fetuin-A using shRNA approach in LN229, significantly reduced their in vitro growth as well as growth and invasion in vivo. The fetuin-A knockdown subclones of LN229 (A and D) also had reduced motility and invasive capacity. Treatment of LN229 cells with asialofetuin (ASF), attenuated their uptake of labeled fetuin-A, and induced senescence in them. Interestingly, the D subclone that had ~90% reduction in ectopic fetuin-A, underwent senescence in serum-free medium which was blunted in the presence of purified fetuin-A. Uptake of labeled exosomes was attenuated in fetuin-A knockdown subclones A and D. Taken together, the studies demonstrate the impact of fetuin-A as significant node of growth, motility, and invasion signaling in glioblastomas that can be targeted for therapy.