New loci associated with birth weight identify genetic links between intrauterine growth and adult height and metabolism.

Birth weight within the normal range is associated with a variety of adult-onset diseases, but the mechanisms behind these associations are poorly understood. Previous genome-wide association studies of birth weight identified a variant in the ADCY5 gene associated both with birth weight and type 2 diabetes and a second variant, near CCNL1, with no obvious link to adult traits. In an expanded genome-wide association meta-analysis and follow-up study of birth weight (of up to 69,308 individuals of European descent from 43 studies), we have now extended the number of loci associated at genome-wide significance to 7, accounting for a similar proportion of variance as maternal smoking. Five of the loci are known to be associated with other phenotypes: ADCY5 and CDKAL1 with type 2 diabetes, ADRB1 with adult blood pressure and HMGA2 and LCORL with adult height. Our findings highlight genetic links between fetal growth and postnatal growth and metabolism

Genomic Dissection of Bipolar Disorder and Schizophrenia, Including 28 Subphenotypes

publisher: Elsevier articletitle: Genomic Dissection of Bipolar Disorder and Schizophrenia, Including 28 Subphenotypes journaltitle: Cell articlelink: https://doi.org/10.1016/j.cell.2018.05.046 content_type: article copyright: © 2018 Elsevier Inc

Local Epidermal Growth Factor Receptor Signaling Mediates the Systemic Pathogenic Effects of Staphylococcus aureus Toxic Shock Syndrome.

Secreted factors of Staphylococcus aureus can activate host signaling from the epidermal growth factor receptor (EGFR). The superantigen toxic shock syndrome toxin-1 (TSST-1) contributes to mucosal cytokine production through a disintegrin and metalloproteinase (ADAM)-mediated shedding of EGFR ligands and subsequent EGFR activation. The secreted hemolysin, α-toxin, can also induce EGFR signaling and directly interacts with ADAM10, a sheddase of EGFR ligands. The current work explores the role of EGFR signaling in menstrual toxic shock syndrome (mTSS), a disease mediated by TSST-1. The data presented show that TSST-1 and α-toxin induce ADAM- and EGFR-dependent cytokine production from human vaginal epithelial cells. TSST-1 and α-toxin also induce cytokine production from an ex vivo porcine vaginal mucosa (PVM) model. EGFR signaling is responsible for the majority of IL-8 production from PVM in response to secreted toxins and live S. aureus. Finally, data are presented demonstrating that inhibition of EGFR signaling with the EGFR-specific tyrosine kinase inhibitor AG1478 significantly increases survival in a rabbit model of mTSS. These data indicate that EGFR signaling is critical for progression of an S. aureus exotoxin-mediated disease and may represent an attractive host target for therapeutics

Alpha-Toxin Promotes Mucosal Biofilm Formation by Staphylococcus aureus

Staphylococcus aureus causes numerous diseases in humans ranging from the mild skin infections to serious, life-threatening, superantigen-mediated Toxic Shock Syndrome (TSS). S. aureus may also be asymptomatically carried in the anterior nares, vagina or on the skin, which serve as reservoirs for infection. Pulsed-field gel electrophoresis clonal type USA200 is the most widely disseminated colonizer and a major cause of TSS. Our prior studies indicated that α-toxin was a major epithelial proinflammatory exotoxin produced by TSS S. aureus USA200 isolates. It also facilitated the penetration of TSS Toxin-1 (TSST-1) across vaginal mucosa. However, the majority of menstrual TSS isolates produce low α-toxin due to a nonsense point mutation at codon 113, designated hly, suggesting mucosal adaptation. The aim of this study was to characterize the differences between TSS USA200 strains [high (hla+) and low (hly+) α-toxin producers] in their abilities to infect and disrupt vaginal mucosal tissue. A mucosal model was developed using ex vivo porcine vaginal mucosa, LIVE/DEAD® staining and confocal microscropy to characterize biofilm formation and tissue viability of TSS USA 200 isolates CDC587 and MN8, which contain the α-toxin pseudogene (hly), MNPE (hla+) and MNPE isogenic hla knockout (hlaKO). All TSS strains grew to similar bacterial densities (1-5 x 108 CFU) on the mucosa and were proinflammatory over 3 days. However, MNPE formed biofilms with significant reductions in the mucosal viability whereas neither CDC587, MN8 (hly+), or MNPE hlaKO, formed biofilms and were less cytotoxic. The addition of exogenous, purified α-toxin to MNPE hlaKO restored the biofilm phenotype. Our studies suggest α-toxin affects S. aureus phenotypic growth on vaginal mucosa, by promoting tissue disruption and biofilm formation; and α–toxin mutants (hly) are not benign colonizers, but rather form a different type of infection, which we have termed high density pathogenic variants (HDPV)

Epidermal growth factor receptor signaling enhances the proinflammatory effects of staphylococcus aureus gamma-toxin on the mucosa

Staphylococcus aureus (S. aureus) produces many different exotoxins including the gamma-toxins, HlgAB and HlgCB. Gamma-toxins form pores in both leukocyte and erythrocyte membranes, resulting in cell lysis. The genes encoding gamma-toxins are present in most strains of S. aureus, and are commonly expressed in clinical isolates recovered from menstrual Toxic Shock Syndrome (mTSS) patients. This study set out to investigate the cytotoxic and proinflammatory effects of gamma-toxins on vaginal epithelial surfaces. We found that both HlgAB and HlgCB were cytotoxic to cultured human vaginal epithelial cells (HVECs) and induced cytokine production at sub-cytotoxic doses. Cytokine production induced by gamma-toxin treatment of HVECs was found to involve epidermal growth factor receptor (EGFR) signaling and mediated by shedding of EGFR ligands from the cell surface. The gamma-toxin subunits displayed differential binding to HVECs (HlgA 93%, HlgB 97% and HlgC 28%) with both components (HlgAB or HlgCB) required for maximum detectable binding and significant stimulation of cytokine production. In studies using full thickness ex vivo porcine vaginal mucosa, HlgAB or HlgCB stimulated a dose-dependent cytokine response, which was reduced significantly by inhibition of EGFR signaling. The effects of gamma-toxins on porcine vaginal tissue and cultured HVECs were validated using ex vivo human ectocervical tissue. Collectively, these studies have identified the EGFR-signaling pathway as a key component in gamma-toxin-induced proinflammatory changes at epithelial surfaces and highlight a potential therapeutic target to diminish toxigenic effects of S. aureus infections

IL-8 production from PVM in response to TSST-1 and α-toxin is dependent on EGFR signaling.

<p>PVM explants were exposed to TSST-1 and/or α-toxin for 6 h and then processed for IL-8 production via ELISA. Where inhibitors were used, they were applied to explants 30 minutes prior to addition of toxin(s). IL-8 is produced in response to both (<b>A</b>) TSST-1 and (<b>B</b>) α-toxin in a dose-dependent manner. For both curves, the asterisks indicate doses showing significant differences from 0 (<i>p</i> < 0.0004). (<b>C</b>) IL-8 production in response to high doses of both TSST-1 (20 μg/explant) and α-toxin (AT) (2 μg/explant) is completely abrogated in the presence of AG1478 (AG– 40 μg/explant), but the dextrin vehicle (Dex– 10 μl of 15%) alone has no affect. Checkered bars represent TSST-1 treatment and striped bars represent AT treatment. Asterisks indicate significant differences from media alone, while crosses indicate significant differences from toxin alone (<i>p</i> < 0.0003). (<b>D</b>) Low doses of TSST-1 (5 μg/explant) and AT (25 ng/explant) have an additive effect on IL-8 production that is reduced to basal levels in the presence of AG1478 (4 μg/explant) with no dextrin vehicle effect (10 μl of 15%). White bars indicate media alone, checkered bars represent TSST-1 treatment, striped bars represent AT treatment, black bars represent TSST-1 + AT treatment. Asterisk indicates significant difference from media, TSST-1 and AT alone (<i>p</i> < 0.03), while cross indicates significant difference from TSST-1 + AT (<i>p</i> < 0.0009).</p

α-toxin induces AREG shedding and IL-8 production from HVECs.

<p>HVECs were exposed to α-toxin for 6 h and then processed for toxicity via MTT assay or IL-8 secretion and AREG shedding via ELISA. Where inhibitors were used, they were applied to HVECs 30 min prior to addition of α-toxin. (<b>A</b>) IL-8 secretion from and (<b>B</b>) viability of HVECs exposed to various doses of α-toxin. For both curves, the asterisks indicate doses showing significant differences from 0 (<i>p</i> < 0.0001). (<b>C</b>) AREG shedding and (<b>D</b>) IL-8 secretion in response to α-toxin is dampened in the presence of TAPI-1 and AG1478. White bars indicate media alone, black bars represent α-toxin treatment at 1 μg/ml. Asterisks indicate significant differences from α-toxin (AT) alone (<i>p</i> < 0.0001). (<b>E</b>) AREG shedding and (<b>F</b>) IL-8 secretion in response to α-toxin are dampened in ADAM10 (A10) and ADAM17 (A17) KD cell lines. White bars indicate media alone on negative control (NC) siRNA cells, black bars represent α-toxin treatment at 1 μg/ml. Asterisks indicate significant differences from α-toxin treated NC cells (<i>p</i> < 0.0001).</p

EGFR signaling is required for mTSS progression <i>in vivo</i>.

<p>(<b>A, B</b>) WT MN8 or MN8 <i>-tstH</i> were administered at 5 x 10⁸ twice daily for 3 days or until death, <i>N</i> = 1, n = 4. (<b>A</b>) Survival is significantly increased (<i>p</i> < 0.0069) and (<b>B</b>) fever is generally reduced in animals challenged with MN8 <i>-tstH</i> versus WT MN8. (<b>C, D</b>) In separate experiments, rabbits were intravaginally challenged with ~ 10¹⁰ MN8 + 8 mg/ml AG1478 or 30% beta cyclodextrin vehicle twice daily for 4 days or until death, <i>N</i> = 1, n = 5. (<b>C</b>) Survival is significantly increased in animals treated with AG1478 (<i>p</i> < 0.03). (<b>D</b>) Fever is generally decreased in animals treated with AG1478 reaching significance at 24 and 36 h, just prior to the death of the majority of infected, untreated animals (<i>p</i> < 0.005).</p

EGFR signaling mediates the PVM IL-8 response to <i>S</i>. <i>aureus</i>.

<p>PVM explants were inoculated with ~ 10⁷ CFU/explant and incubated for 6 h ± 4 μg/explant AG1478 (AG) or 4 μl/explant 10% DMSO vehicle prior to processing for IL-8 production (via ELISA) and CFU determination. (A-E) White bar, uninfected control (CNTL), black bars indicate presence of bacteria. Incubation of PVM with AG prior to infection with (<b>A</b>) MNPE, (<b>B</b>) MNPE <i>-tstH</i>, (<b>C</b>) MN8, or (<b>D</b>) MN8 <i>-tstH</i> significantly reduced IL-8 production (asterisks, <i>p</i> < 0.0002). DMSO alone had no effect.</p