NAD+ metabolism is a key modulator of bacterial respiratory epithelial infections

Lower respiratory tract infections caused by Streptococcus pneumoniae (Spn) are a leading cause of death globally. Here we investigate the bronchial epithelial cellular response to Spn infection on a transcriptomic, proteomic and metabolic level. We found the NAD+ salvage pathway to be dysregulated upon infection in a cell line model, primary human lung tissue and in vivo in rodents, leading to a reduced production of NAD+. Knockdown of NAD+ salvage enzymes (NAMPT, NMNAT1) increased bacterial replication. NAD+ treatment of Spn inhibited its growth while growth of other respiratory pathogens improved. Boosting NAD+ production increased NAD+ levels in immortalized and primary cells and decreased bacterial replication upon infection. NAD+ treatment of Spn dysregulated the bacterial metabolism and reduced intrabacterial ATP. Enhancing the bacterial ATP metabolism abolished the antibacterial effect of NAD+. Thus, we identified the NAD+ salvage pathway as an antibacterial pathway in Spn infections, predicting an antibacterial mechanism of NAD+.

Screening for eukaryotic motifs in Legionella pneumophila reveals Smh1 as bacterial deacetylase of host histones

Legionella pneumophila (L.p.) is a bacterial pathogen which is a common causative agent of pneumonia. In humans, it infects alveolar macrophages and transfers hundreds of virulence factors that interfere with cellular signalling pathways and the transcriptomic landscape to sustain its own replication. By this interaction, it has acquired eukaryote-like protein motifs by gene transfer events that partake in the pathogenicity of Legionella. In a computational screening approach for eukaryotic motifs in the transcriptome of Legionella, we identified the L.p. strain Corby protein ABQ55614 as putative histone-deacetylase and named it "suppressing modifier of histones 1" (Smh1). During infection, Smh1 is translocated from the Legionella vacuole into the host cytosol. When expressed in human macrophage THP-1 cells, Smh1 was localized predominantly in the nucleus, leading to broad histone H3 and H4 deacetylation, blunted expression of a large number of genes (e.g. IL-1β and IL-8), and fostered intracellular bacterial replication. L.p. with a Smh1 knockdown grew normally in media but showed a slight growth defect inside the host cell. Furthermore, Smh1 showed a very potent histone deacetylation activity in vitro, e.g. at H3K14, that could be inhibited by targeted mutation of the putative catalytic center inferred by analogy with eukaryotic HDAC8, and with the deacetylase inhibitor trichostatin A. In summary, Smh1 displays functional homology with class I/II type HDACs. We identified Smh1 as a new Legionella virulence factor with a eukaryote-like histone-deacetylase activity that moderates host gene expression and might pave the way for further histone modifications.IMPORTANCELegionella pneumophila (L.p.) is a prominent bacterial pathogen, which is a common causative agent of pneumonia. In order to survive inside the host cell, the human macrophage, it profoundly interacts with host cell processes to advance its own replication. In this study, we identify a bacterial factor, Smh1, with yet unknown function as a host histone deacetylase. The activity of this factor in the host cell leads to attenuated gene expression and increased intracellular bacterial replication.

Alpha-1 antitrypsin inhibits RANKL-induced osteoclast formation and functions

Osteoporosis is a global public health problem affecting more than 200 million people worldwide. We previously showed that treatment with alpha-1 antitrypsin (AAT), a multifunctional protein with anti-inflammatory properties, mitigated bone loss in an ovariectomized mouse model. However, the underlying mechanisms of the protective effect of AAT on bone tissue are largely unknown. In this study, we investigated the effect of AAT on osteoclast formation and function in vitro. Our results showed that AAT dose-dependently inhibited the formation of RANKL (receptor activator of nuclear factor κB ligand) induced osteoclasts derived from mouse bone marrow macrophages/monocyte (BMM) lineage cells and the murine macrophage cell line, RAW 264.7 cells. In order to elucidate the possible mechanisms underlying this inhibition, we tested the effect of AAT on the gene expression of cell surface molecules, transcription factors, and cytokines associated with osteoclast formation. We showed that AAT inhibited M-CSF (macrophage colony-stimulating factor) induced cell surface RANK expression in osteoclast precursor cells. In addition, AAT inhibited RANKL-induced TNF-α production, cell surface CD9 expression, and dendritic cell-specific transmembrane protein (DC-STAMP) gene expression. Importantly, AAT treatment significantly inhibited osteoclast-associated mineral resorption. Together, these results uncovered new mechanisms for the protective effects of AAT and strongly support the notion that AAT has therapeutic potential for the treatment of osteoporosis.

Effect of non nutritive sucking on the behavioral state and physiological change in premature infants before feeding

Premature infants display few behaviors that provide quantitative information about their maturational development, making it difficult to carry out appropriate care. This study was performed to investigate the effect of non-nutritive sucking on behavioral state and physiological changes in premature infants. They were selected from premature unit of Main University Hospital at Tanta city. Forty premature infants were divided into two groups, nonnutritive sucking and no non-nutritive sucking. Personal characteristics were obtained from medical records. Anderson Behavioral State Scoring Systems were used and observed four times daily. Physiological changes were noticed; temperature, heart and respiratory rates The present study revealed that the time spent in sleep states was decreased and time spent in awake states was increased, when compared to no non-nutritive sucking group (ONNS). There was Statistically significant differences within the two groups related to behavior states and physiological changes. The development of sucking reflex was accelerated among premature in the non-nutritive sucking group. They shift earlier to oral feeding and their discharge was earlier.

Inhibition of steroid sex hormones release in rats by two Ca2+ channel blockers

The calcium channel blockers Diltiazem HCl (2 mg kg-1 day-1, IP) or Cinnarizine (8 mg kg-1 day-1, IP) were given for a period of 30 days to adult male and female albino rats. The effect of each calcium channel blocker on circulating blood levels of steroid sex hormones was investigated by radioimmunoassay in comparison with the normal control level. The data demonstrated that both Diltiazem and Cinnarizine significantly decreased serum normal testosterone levels in males (36% and 52% inhibition respectively) as well as both normal estradiol and progesterone contents in females (58% and 45% inhibition with Diltiazem and 68% and 52% inhibition with Cinnarizine respectively). This study indicates the importance of blood sex hormones-follow up in case of long term Ca2+ channel blockers medication.

The effect of thiola, piroxicam and diltiazem on the uterine contractility of gamma-irradiated rats

Accidental radiation exposure raises concern for functional modifications in the uterine physiology. In the current work, total body gamma-irradiation (0.7, 1.4 and 2.1 Gy) of non-pregnant adult female albino rats increased significantly the frequency and amplitude of uterine contractions in vivo. Administration of Thiola (a sulfhydryl containing agent) in doses of 100 or 250 mg kg-1, pre-irradiation or Piroxicam (a potent prostaglandin inhibitor) in a dose of 2 mg kg-1, pre- or post-irradiation failed to normalize the changes induced by gamma-irradiation. However, administration of Diltiazem (a Ca2+ channel blocker, 8 mg kg-1) pre- or post-irradiation caused a significant decrease in the frequency of uterine contractions (21% and 24% respectively) in comparison to the uterotonic pattern of gamma-irradiation alone. The results indicate a promising tocolytic activity of Diltiazem against the uterotonic effect of gamma-radiation.