-
Biochemical and Biophysical Research... May 2017Citrullination is an important posttranslational modification that occurs during retinal gliosis. We examined the expression of peptidyl arginine deiminases (PADs) to...
Citrullination is an important posttranslational modification that occurs during retinal gliosis. We examined the expression of peptidyl arginine deiminases (PADs) to identify the PADs that mediate citrullination in a model of alkali-induced retinal gliosis. Mouse corneas were exposed to 1.0 N NaOH and posterior eye tissue from injured and control uninjured eyes was evaluated for transcript levels of various PADs by reverse-transcription polymerase chain reaction (RT-PCR), and quantitative RT-PCR (qPCR). Retinas were also subjected to immunohistochemistry (IHC) for glial fibrillary acidic protein (GFAP), citrullinated species, PAD2, and PAD4 and tissue levels of GFAP, citrullinated species, and PAD4 were measured by western blots. In other experiments, the PAD4 inhibitor streptonigrin was injected intravitreally into injured eyes ex vivo to test inhibitory activity in an organ culture system. We found that uninjured retina and choroid expressed Pad2 and Pad4 transcripts. Pad4 transcript levels increased by day 7 post-injury (p < 0.05), whereas Pad2 levels did not change significantly (p > 0.05) by qPCR. By IHC, PAD2 was expressed in uninjured eyes along ganglion cell astrocytes, but in injured retina PAD2 was downregulated at 7 days. On the other hand, PAD4 showed increased staining in the retina upon injury revealing a pattern that overlapped with filamentous GFAP staining in Müller glial processes by 7 days. Injury-induced citrullination and soluble GFAP protein levels were reduced by PAD4 inhibition in western blot experiments of organ cultures. Together, our findings for the first time identify PAD4 as a novel injury-inducible druggable target for retinal gliosis.
Topics: Animals; Arginine; Burns, Chemical; Citrulline; Eye Burns; Female; Gliosis; Hydrolases; Male; Mice; Protein-Arginine Deiminase Type 4; Retina; Retinal Diseases; Sodium Hydroxide
PubMed: 28400047
DOI: 10.1016/j.bbrc.2017.04.031 -
Cell Death & Disease May 2017The role of connexin proteins (Cx), which form gap junctions (GJ), in progression and chemotherapeutic sensitivity of cervical cancer (CaCx), is unclear. Using cervix...
The role of connexin proteins (Cx), which form gap junctions (GJ), in progression and chemotherapeutic sensitivity of cervical cancer (CaCx), is unclear. Using cervix specimens (313 CaCx, 78 controls) and CaCx cell lines, we explored relationships among Cx expression, prognostic variables and mechanisms that may link them. In CaCx specimens, Cx32 was upregulated and cytoplasmically localized, and three other Cx downregulated, relative to controls. Cx32 expression correlated with advanced FIGO staging, differentiation and increased tumor size. In CaCx cell lines, Cx32 expression suppressed streptonigrin/cisplatin-induced apoptosis in the absence of functional GJ. In CaCx specimens and cell lines, expression of Cx32 upregulated epidermal growth factor receptor (EGFR) expression. Inhibition of EGFR signaling abrogated the anti-apoptotic effect of Cx32 expression. In conclusion, upregulated Cx32 in CaCx cells produces anti-apoptotic, pro-tumorigenic effects in vivo and vitro. Abnormal Cx32 expression/localization in CaCx appears to be both a mechanism and biomarker of chemotherapeutic resistance.
Topics: Apoptosis; Biomarkers, Tumor; Connexins; Drug Resistance, Neoplasm; ErbB Receptors; Female; HeLa Cells; Humans; Neoplasm Proteins; Uterine Cervical Neoplasms; Gap Junction beta-1 Protein
PubMed: 28492539
DOI: 10.1038/cddis.2017.183 -
Journal of Biotechnology Nov 2014The Fur protein is the main sensor of cellular iron status in bacteria. In the present study, we inactivated the fur gene of Pseudomonas pseudoalcaligenes CECT5344 and...
The Fur protein is the main sensor of cellular iron status in bacteria. In the present study, we inactivated the fur gene of Pseudomonas pseudoalcaligenes CECT5344 and characterized the resulting mutant. Our findings provide experimental evidence that, cyanide generates an intracellular signal equivalent to that triggered by iron deprivation, as witnessed by the induction of prrF and fiuA (ferrichrome receptor) expression in the presence of cyanide. The fur mutant also displayed slow growth, especially in minimal culture medium, increased sensitivity to cyanide in LB medium and as expected, resistance to manganese ions. Moreover, the mutant exhibited enhanced iron accumulation and increased sensitivity to streptonigrin, as well as to some inducers of oxidative stress, such as paraquat and menadione, yet it remained resistant to hydrogen peroxide. Surprisingly, neither the wild type strain nor the fur mutant strain produced siderophores that could be detected using the universal CAS-agar method.
Topics: Bacterial Proteins; Cyanides; Hydrogen Peroxide; Iron; Mutation; Oxidative Stress; Phenotype; Pseudomonas pseudoalcaligenes; Repressor Proteins; Streptonigrin
PubMed: 24704534
DOI: 10.1016/j.jbiotec.2014.03.030 -
Veterinary Research Mar 2021Iron is essential for most bacteria to survive, but excessive iron leads to damage by the Fenton reaction. Therefore, the concentration of intracellular free iron must...
Iron is essential for most bacteria to survive, but excessive iron leads to damage by the Fenton reaction. Therefore, the concentration of intracellular free iron must be strictly controlled in bacteria. Riemerella anatipestifer (R. anatipestifer), a Gram-negative bacterium, encodes the iron uptake system. However, the iron homeostasis mechanism remains largely unknown. In this study, it was shown that compared with the wild type R. anatipestifer CH-1, R. anatipestifer CH-1Δfur was more sensitive to streptonigrin, and this effect was alleviated when the bacteria were cultured in iron-depleted medium, suggesting that the fur mutant led to excess iron accumulation inside cells. Similarly, compared with R. anatipestifer CH-1∆recA, R. anatipestifer CH-1∆recAΔfur was more sensitive to HO-induced oxidative stress when the bacteria were grown in iron-rich medium rather than iron-depleted medium. Accordingly, it was shown that R. anatipestifer CH-1∆recAΔfur produced more intracellular ROS than R. anatipestifer CH-1∆recA in iron-rich medium. Electrophoretic mobility shift assays showed that R. anatipestifer CH-1 Fur suppressed the transcription of putative iron uptake genes through binding to their promoter regions. Finally, it was shown that compared with the wild type, R. anatipestifer CH-1Δfur was significantly attenuated in ducklings and that the colonization ability of R. anatipestifer CH-1Δfur in various tissues or organs was decreased. All these results suggested that Fur is important for iron homeostasis in R. anatipestifer and its pathogenic mechanism.
Topics: Bacterial Proteins; Iron; Oxidative Stress; Riemerella; Virulence
PubMed: 33741064
DOI: 10.1186/s13567-021-00919-9 -
Angewandte Chemie (International Ed. in... Jan 2023We report that axially chiral biaryl boronic esters can be generated with control of atroposelectivity by a Binol-mediated dynamic thermodynamic resolution process....
We report that axially chiral biaryl boronic esters can be generated with control of atroposelectivity by a Binol-mediated dynamic thermodynamic resolution process. These intermediates can be progressed to enantioenriched products through stereoretentive functionalization of the carbon-boron bond. Finally, we have exploited this method in the first highly stereoselective total synthesis of P-streptonigrin.
PubMed: 36377668
DOI: 10.1002/anie.202213692 -
The Journal of Antimicrobial... Jun 2024Riemerella anatipestifer encodes an iron acquisition system, but whether it encodes the iron efflux pump and its role in antibiotic resistance are largely unknown.
BACKGROUND
Riemerella anatipestifer encodes an iron acquisition system, but whether it encodes the iron efflux pump and its role in antibiotic resistance are largely unknown.
OBJECTIVES
To screen and identify an iron efflux gene in R. anatipestifer and determine whether and how the iron efflux gene is involved in antibiotic resistance.
METHODS
In this study, gene knockout, streptonigrin susceptibility assay and inductively coupled plasma mass spectrometry were used to screen for the iron efflux gene ietA. The MIC measurements, scanning electron microscopy and reactive oxygen species (ROS) detection were used to verify the role of IetA in aztreonam resistance and its mechanism. Mortality and colonization assay were used to investigate the role of IetA in virulence.
RESULTS
The deletion mutant ΔietA showed heightened susceptibility to streptonigrin, and prominent intracellular iron accumulation was observed in ΔfurΔietA under excess iron conditions. Additionally, ΔietA exhibited increased sensitivity to H2O2-produced oxidative stress. Under aerobic conditions with abundant iron, ΔietA displayed increased susceptibility to the β-lactam antibiotic aztreonam due to heightened ROS production. However, the killing efficacy of aztreonam was diminished in both WT and ΔietA under anaerobic or iron restriction conditions. Further experiments demonstrated that the efficiency of aztreonam against ΔietA was dependent on respiratory complexes Ⅰ and Ⅱ. Finally, in a duckling model, ΔietA had reduced virulence compared with the WT.
CONCLUSION
Iron efflux is critical to alleviate oxidative stress damage and β-lactam aztreonam killing in R. anatipestifer, which is linked by cellular respiration.
Topics: Oxidative Stress; Iron; Animals; Microbial Sensitivity Tests; Anti-Bacterial Agents; Riemerella; Aztreonam; Flavobacteriaceae Infections; Virulence; beta-Lactam Resistance; Ducks; Reactive Oxygen Species; Membrane Transport Proteins; Streptonigrin; Gene Knockout Techniques; Poultry Diseases; Bacterial Proteins
PubMed: 38629469
DOI: 10.1093/jac/dkae114 -
PloS One 2021The foodborne pathogen Listeria monocytogenes is able to survive across a wide range of intra- and extra-host environments by appropriately modulating gene expression...
The foodborne pathogen Listeria monocytogenes is able to survive across a wide range of intra- and extra-host environments by appropriately modulating gene expression patterns in response to different stimuli. Positive Regulatory Factor A (PrfA) is the major transcriptional regulator of virulence gene expression in L. monocytogenes. It has long been known that activated charcoal is required to induce the expression of PrfA-regulated genes in complex media, such as Brain Heart Infusion (BHI), but not in chemically defined media. In this study, we show that the expression of the PrfA-regulated hly, which encodes listeriolysin O, is induced 5- and 8-fold in L. monocytogenes cells grown in Chelex-treated BHI (Ch-BHI) and in the presence of activated charcoal (AC-BHI), respectively, relative to cells grown in BHI medium. Specifically, we show that metal ions present in BHI broth plays a role in the reduced expression of the PrfA regulon. In addition, we show that expression of hly is induced when the levels of bioavailable extra- or intercellular iron are reduced. L. monocytogenes cells grown Ch-BHI and AC-BHI media showed similar levels of resistance to the iron-activated antibiotic, streptonigrin, indicating that activated charcoal reduces the intracellular labile iron pool. Metal depletion and exogenously added glutathione contributed synergistically to PrfA-regulated gene expression since glutathione further increased hly expression in metal-depleted BHI but not in BHI medium. Analyses of transcriptional reporter fusion expression patterns revealed that genes in the PrfA regulon are differentially expressed in response to metal depletion, metal excess and exogenous glutathione. Our results suggest that metal ion abundance plays a role in modulating expression of PrfA-regulated virulence genes in L. monocytogenes.
Topics: Bacterial Proteins; Bacterial Toxins; Charcoal; Culture Media; Gene Expression Regulation, Bacterial; Glutathione; Heat-Shock Proteins; Hemolysin Proteins; Iron; Listeria monocytogenes; Peptide Termination Factors; Polystyrenes; Polyvinyls; Streptonigrin; Virulence; Zinc
PubMed: 33914817
DOI: 10.1371/journal.pone.0250989 -
Plants (Basel, Switzerland) Jun 2024Lemon essential oil, derived from , possesses diverse health-promoting properties, including antioxidant, antimicrobial, and mood-enhancing effects. Despite its...
Lemon essential oil, derived from , possesses diverse health-promoting properties, including antioxidant, antimicrobial, and mood-enhancing effects. Despite its traditional use in aromatherapy and complementary medicine, there is a need for comprehensive investigations into its therapeutic potential, particularly in mitigating DNA damage and supporting health in palliative care settings. This study aimed to evaluate the antigenotoxic effects of lemon essential oil in human peripheral blood mononuclear cells and to explore its potential applications in palliative care. Treatment with lemon essential oil significantly reduced DNA damage, with 1% w/v with 3.13% DNA in tail demonstrating greater efficacy. Furthermore, lemon essential oil attenuated streptonigrin-induced DNA damage, suggesting a potential protective effect against oxidative stress, especially at 3% w/v, with 11.81% DNA in tail. Compared to olive oil treatment, the DNA damage was significantly lower with streptonigrin treatment alone, which had 47.06% DNA in tail, while the olive oil treatment resulted in 36.88% DNA in tail. These results can be attributed to the main constituents: limonene in lemon essential oil and oleic acid in olive oil. These results suggest a potential role in mitigating oxidative stress and supporting genomic stability. Further research is warranted to elucidate the mechanisms of action and clinical applications in palliative care.
PubMed: 38931055
DOI: 10.3390/plants13121623 -
Journal of Bacteriology Jun 2020Group A streptococcus (GAS) produces millions of infections worldwide, including mild mucosal infections, postinfection sequelae, and life-threatening invasive diseases....
Group A streptococcus (GAS) produces millions of infections worldwide, including mild mucosal infections, postinfection sequelae, and life-threatening invasive diseases. During infection, GAS readily acquires nutritional iron from host heme and hemoproteins. Here, we identified a new heme importer, named SiaFGH, and investigated its role in GAS pathophysiology. The SiaFGH proteins belong to a group of transporters with an unknown ligand from the recently described family of energy coupling factors (ECFs). A deletion mutant exhibited high streptonigrin resistance compared to the parental strain, suggesting that iron ions or an iron complex is the likely ligand. Iron uptake and inductively coupled plasma mass spectrometry (ICP-MS) studies showed that the loss of did not impact GAS import of ferric or ferrous iron, but the mutant was impaired in using hemoglobin iron for growth. Analysis of cells growing on hemoglobin iron revealed a substantial decrease in the cellular heme content in the mutant compared to the complemented strain. The induction of the genes in resulted in the induction of heme uptake. The mutant exhibited a significant impairment in murine models of mucosal colonization and systemic infection. Together, the data show that SiaFGH is a new type of heme importer that is key for GAS use of host hemoproteins and that this system is imperative for bacterial colonization and invasive infection. ECF systems are new transporters that take up various vitamins, cobalt, or nickel with a high affinity. Here, we establish the GAS SiaFGH proteins as a new ECF module that imports heme and demonstrate its importance in virulence. SiaFGH is the first heme ECF system described in bacteria. We identified homologous systems in the genomes of related pathogens from the phylum. Notably, GAS and other pathogens that use a SiaFGH-type importer rely on host hemoproteins for a source of iron during infection. Hence, recognizing the function of this noncanonical ABC transporter in heme acquisition and the critical role that it plays in disease has broad implications.
Topics: Animals; Bacterial Proteins; Biological Transport; Female; Gene Expression Regulation, Bacterial; Heme; Humans; Iron; Membrane Transport Proteins; Mice; Streptococcal Infections; Streptococcus pyogenes; Virulence
PubMed: 32393520
DOI: 10.1128/JB.00205-20 -
Iranian Journal of Pharmaceutical... 2019Quinones such as 1,4-naphthoquinones are abundant in nature and naphthoquinone based natural products are known to possess anticancer activity. This pharmacophore is...
Quinones such as 1,4-naphthoquinones are abundant in nature and naphthoquinone based natural products are known to possess anticancer activity. This pharmacophore is known to convey anticancer activity to some drugs such as streptonigrin, mitomycin A, . We synthesized and characterized different classes of naphthoquinone derivatives including bis naphthoquinone, 2-arylaminonaphthoquinone, benzoxantene-6,11-dione and benzoacridine-5,6-dione derivatives instead of the expected 2-hydroxy-3-(substituted phenyl(aryl amino)methyl)naphthalene-1,4-dione derivatives from the reaction of 2-hydroxy1,4-naphthoquinone (lawson) with different benzaldehydes and aryl amines. Benzoacridine-5,6-dione derivatives and related imines showed potent anti-breast cancer activity in MCF-7 cancer cells. The results revealed that five compounds benzoacridinedione derivatives ( and ) and imines (, and ) by the IC range of 5.4-47.99 μM are the most potent anti-breast cancer structures.
PubMed: 31089340
DOI: No ID Found