Full-length structure and heme binding in the transcriptional regulator HcpR.

HcpR is a CRP-family transcriptional regulator found in many Gram-negative anaerobic bacteria. In the perio-pathogen Porphyromonas gingivalis, HcpR is crucial for the response to reactive nitrogen species such as nitric oxide (NO). Binding of NO to the heme group of HcpR leads to transcription of the redox enzyme Hcp.

Targeting of SUMOylation leads to cBAF complex stabilization and disruption of the SS18::SSX transcriptome in Synovial Sarcoma.

Synovial Sarcoma (SS) is driven by the SS18::SSX fusion oncoprotein and is ultimately refractory to therapeutic approaches. SS18::SSX alters ATP-dependent chromatin remodeling BAF (mammalian SWI/SNF) complexes, leading to the degradation of canonical (cBAF) complex and amplified presence of an SS18::SSX-containing non-canonical BAF (ncBAF or GBAF) that drives an SS-specific transcription program and tumorigenesis. We demonstrate that SS18::SSX activates the SUMOylation program and SSs are sensitive to the small molecule SAE1/2 inhibitor, TAK-981.

Targeting of SUMOylation leads to cBAF complex stabilization and disruption of the SS18::SSX transcriptome in Synovial Sarcoma.

Synovial Sarcoma (SS) is driven by the SS18::SSX fusion oncoprotein. and is ultimately refractory to therapeutic approaches. SS18::SSX alters ATP-dependent chromatin remodeling BAF (mammalian SWI/SNF) complexes, leading to the degradation of canonical (cBAF) complex and amplified presence of an SS18::SSX-containing non-canonical BAF (ncBAF or GBAF) that drives an SS-specific transcription program and tumorigenesis.

Iron Deficiency Modulates Metabolic Landscape of Promoting Its Resilience during Inflammation.

Bacteria have to persist under low iron conditions in order to adapt to the nutritional immunity of a host. Since the knowledge of iron stimulon of is sparse, we examined oral (Porphyromonas gingivalis and Prevotella intermedia) and gut (Bacteroides thataiotaomicron) representatives for their ability to adapt to iron deplete and iron replete conditions. Our transcriptomics and comparative genomics analysis show that many iron-regulated mechanisms are conserved within the phylum.

Ferroportin depletes iron needed for cell cycle progression in head and neck squamous cell carcinoma.

Introduction: Ferroportin (FPN), the only identified eukaryotic iron efflux channel, plays an important role in iron homeostasis and is downregulated in many cancers. To determine if iron related pathways are important for Head and Neck Squamous Cell Carcinoma (HNSCC) progression and proliferation, we utilize a model of FPN over-expression to simulate iron depletion and probe associated molecular pathways.

Methods: The state of iron related proteins and ferroptosis sensitivity was assessed in a panel of metastatic HNSCC cell lines.

Non-human Primate as an Animal Model for Testing Efficacy of Amixicile as a Targeted Anti-periodontitis Therapy.

Periodontitis is an inflammatory condition triggered by selected oral microbiota; thus treatment strategies should be aimed at reducing the abundance of the pathogenic bacteria. An obstacle to preclinical testing of such strategies is the availability of reliable animal models. Here, a non-human primate (NHP), , was used to examine the effectiveness of a novel antimicrobial, amixicile, which inhibits pyruvate-ferredoxin oxidoreductase (PFOR) present in anaerobic bacteria.

Insertional Inactivation of OxyR Results in Reduced Survival with Oxidative Stress and in the Presence of Host Cells.

One of the most abundant bacteria in the subgingival pockets of patients with bleeding following mechanical periodontal therapy is However, despite its abundance, the molecular mechanisms of its contribution to periodontal disease are not well known. This is mainly due to the lack of genetic tools that would allow examination of the role of predicted virulence factors in the pathogenesis of this bacterium. Here, we report on the first mutant in the OMA14 strain.

-Amplified Neuroblastoma Is Addicted to Iron and Vulnerable to Inhibition of the System Xc-/Glutathione Axis.

is amplified in 20% to 25% of neuroblastoma, and -amplified neuroblastoma contributes to a large percent of pediatric cancer-related deaths. Therapy improvements for this subtype of cancer are a high priority. Here we uncover a MYCN-dependent therapeutic vulnerability in neuroblastoma.

Treatment with Nd:YAG Laser Irradiation Combined with or Irrigation on Periodontal Pathogens: An Study.

The purpose of this study was to evaluate the effect of neodymium-doped yttrium aluminum garnet (Nd:YAG) laser with low concentrations of hydrogen peroxide (HO) or sodium hypochlorite (NaOCl) on viability of oral bacteria. Bacterial species , , and were grown in an anaerobic chamber at 37°C. Samples were irradiated with the Nd:YAG laser (1064 nm, 300 μm Varian tip) using parameters: 150 mJ, 20 Hz, 3 W, 50 sec, and 100 μs short pulse duration in contact mode.

Sequence and characterization of shuttle vectors for molecular cloning in Porphyromonas, Bacteroides and related bacteria.

There is a lack of shuttle vectors to be needed for investigations into the genetics of Porphyromonas gingivalis and related species. To better understand the prevalence of candidates for such tools, we have examined multiple strains of black-pigmented anaerobes (clinical and laboratory isolates) for plasmids. As no plasmids were found in P.

Amixicile depletes the ex vivo periodontal microbiome of anaerobic bacteria.

Objectives: Although periodontal diseases result from overgrowth of anaerobic bacteria, the effect of a specific knockdown of anaerobes on the disease outcome has yet to be examined. We have reported that amixicile, a non-toxic, readily bioavailable, and novel antimicrobial, specifically targets selected oral anaerobes through inhibition of the activity of pyruvate ferredoxin oxidoreductase (PFOR), a major enzyme mediating oxidative decarboxylation of pyruvate.

Methods: Here, we generated an ex vivo microbiome derived from gingival pockets of human subjects with chronic periodontal disease and evaluated the efficacy of amixicile in generating a specific knockdown of anaerobic bacteria present in the microbiome.

Amixicile targets anaerobic bacteria within the oral microbiome.

Objectives: Anaerobic bacteria are the major causative agents of periodontal disease. However, so far, targeted therapy aimed at reducing those pathogens has not been widely implemented. We have previously reported on a novel antimicrobial, amixicile, that targets anaerobic bacteria through inhibition of the function of the major anaerobic metabolic enzyme pyruvate ferredoxin oxidoreductase (PFOR), while not affecting aerotolerant organisms.

Nitrosative stress sensing in Porphyromonas gingivalis: structure of and heme binding by the transcriptional regulator HcpR.

Although the HcpR regulator plays a vital step in initiation of the nitrosative stress response in many Gram-negative anaerobic bacteria, the molecular mechanisms that it uses to mediate gas sensing are not well understood. Here, a 2.6 Å resolution crystal structure of the N-terminal sensing domain of the anaerobic periodontopathogen Porphyromonas gingivalis HcpR is presented.

The Hybrid Cluster Protein Hcp Is Required for Growth with Nitrite and Survival with Host Cells.

Although the periodontal pathogen must withstand high levels of nitrosative stress while in the oral cavity, the mechanisms of nitrosative stress defense are not well understood in this organism. Previously we showed that the transcriptional regulator HcpR plays a significant role in defense, and here we further defined its regulon. Our study shows that (PG0893), a putative nitric oxide (NO) reductase, is the only gene significantly upregulated in response to nitrite (NO) and that this regulation is dependent on HcpR.

Amixicile, a novel strategy for targeting oral anaerobic pathogens.

The oral microflora is composed of both health-promoting as well as disease-initiating bacteria. Many of the disease-initiating bacteria are anaerobic and include organisms such as Porphyromonas gingivalis, Prevotella intermedia, Fusobacterium nucleatum, and Tannerella forsythia. Here we investigated a novel therapeutic, amixicile, that targets pyruvate:ferredoxin oxidoreductase (PFOR), a major metabolic enzyme involved in energy generation through oxidative decarboxylation of pyruvate.

Porphyromonas gingivalis as a Model Organism for Assessing Interaction of Anaerobic Bacteria with Host Cells.

Anaerobic bacteria far outnumber aerobes in many human niches such as the gut, mouth, and vagina. Furthermore, anaerobic infections are common and frequently of indigenous origin. The ability of some anaerobic pathogens to invade human cells gives them adaptive measures to escape innate immunity as well as to modulate host cell behavior.

Interaction of Prevotella intermedia strain 17 leucine-rich repeat domain protein AdpF with eukaryotic cells promotes bacterial internalization.

Prevotella intermedia is an oral bacterium implicated in a variety of oral diseases. Although internalization of this bacterium by nonphagocytic host cells is well established, the molecular players mediating the process are not well known. Here, the properties of a leucine-rich repeat (LRR) domain protein, designated AdpF, are described.

Structures of the Porphyromonas gingivalis OxyR regulatory domain explain differences in expression of the OxyR regulon in Escherichia coli and P. gingivalis.

OxyR transcriptionally regulates Escherichia coli oxidative stress response genes through a reversibly reducible cysteine disulfide biosensor of cellular redox status. Structural changes induced by redox changes in these cysteines are conformationally transmitted to the dimer subunit interfaces, which alters dimer and tetramer interactions with DNA. In contrast to E.

HcpR of Porphyromonas gingivalis is required for growth under nitrosative stress and survival within host cells.

Although the Gram-negative, anaerobic periodontopathogen Porphyromonas gingivalis must withstand nitrosative stress, which is particularly high in the oral cavity, the mechanisms allowing for protection against such stress are not known in this organism. In this study, microarray analysis of P. gingivalis transcriptional response to nitrite and nitric oxide showed drastic upregulation of the PG0893 gene coding for hybrid cluster protein (Hcp), which is a putative hydroxylamine reductase.

The capsule of Porphyromonas gingivalis leads to a reduction in the host inflammatory response, evasion of phagocytosis, and increase in virulence.

Periodontal disease is a chronic oral inflammatory disease that is triggered by bacteria such as Porphyromonas gingivalis. P. gingivalis strains exhibit great heterogeneity, with some strains being encapsulated while others are nonencapsulated.

AdpC is a Prevotella intermedia 17 leucine-rich repeat internalin-like protein.

The oral bacterium Prevotella intermedia attaches to and invades gingival epithelial cells, fibroblasts, and endothelial cells. Several genes encoding proteins that mediate both the adhesion and invasion processes are carried on the genome of this bacterium. Here, we characterized one such protein, AdpC, belonging to the leucine-rich repeat (LRR) protein family.

Porphyromonas gingivalis ferrous iron transporter FeoB1 influences sensitivity to oxidative stress.

Porphyromonas gingivalis FeoB1 is a ferrous iron transporter. Analysis of parental and feoB1-deficient strains of the periodontal pathogen revealed that the feoB1-deficient mutant strain had an increased ability to survive oxidative stress. Specifically, survival of the mutant strain was increased 33% with exposure to peroxide and 5% with exposure to atmospheric oxygen compared to the parental strain.

Adaptation of Porphyromonas gingivalis to microaerophilic conditions involves increased consumption of formate and reduced utilization of lactate.

Porphyromonas gingivalis, previously classified as a strict anaerobe, can grow in the presence of low concentrations of oxygen. Microarray analysis revealed alteration in gene expression in the presence of 6 % oxygen. During the exponential growth phase, 96 genes were upregulated and 79 genes were downregulated 1.