Proteoglycans (PGs) and their associated glycosaminoglycan (GAG) side chains are effectors of inflammation, but little is known about changes to the composition of PGs in response to lung infection or injury. The goals of this study were to identify changes to heparan sulfate proteoglycans (HSPG) in a mouse model of gram-negative pneumonia; to identify the Toll-like receptor adaptor molecules responsible for these changes; and to determine the role of the HSPG in the innate immune response in the lungs. We treated mice with intratracheal (IT) lipopolysaccharide (LPS), a component of the cell wall of gram-negative bacteria, to model gram-negative pneumonia. Mice treated with IT LPS had a rapid and selective increase in syndecan-4 mRNA that was regulated through MyD88-dependent mechanisms, whereas expression of several other PGs was not affected. To determine the role of syndecan-4 in the inflammatory response, we exposed mice deficient in syndecan-4 to LPS and found a significant increase in neutrophil numbers and amounts of CXC-chemokines and total protein in bronchoalveolar lavage (BAL) fluid. In studies performed in vitro, macrophages and epithelial cells treated with LPS had increased expression of syndecan-4. Studies performed using BEAS-2B cells showed that pretreatment with heparin and syndecan-4 decreased the expression of CXCL8 mRNA in response to LPS and TNFα. These findings indicate that the early inflammatory response to LPS involves marked upregulation of syndecan-4, which functions to limit the extent of pulmonary inflammation and lung injury.

In this study we estimated the combined effects of violence experiences, parenting processes, and community poverty on sexual onset, alcohol or other drug (AOD) use at last sex, multiple sex partners, and prior pregnancy in a sample of 7th-, 9th-, and 11th-grade adolescents (n = 7,891), and the subsample of sexually experienced adolescents (n = 2,108). Multilevel multivariate logistic regression analyses revealed that having experienced any interpersonal violence, and low levels of perceived parental warmth and parental knowledge predicted sexual onset. Adult sexual abuse or peer sexual coercion increased the odds for AOD use at last sex and having multiple sexual partners. When demographic, violence experiences and parenting behaviors were accounted for, poverty was not associated with sexual onset, AOD use at last sex, or multiple sex partners. Results suggest prevention efforts to reduce teen dating violence may be especially important to diminish sexually risky behaviors among adolescents.

Students' perceptions of their school climates are associated with psychosocial and academic adjustment. The present study examined the role of school strategies to promote safety in predicting students' perceptions of safety for gender nonconforming peers among 1415 students in 28 high schools. Using multilevel modeling techniques, we examined student- and school-level effects on students' perceptions of safety for gender nonconforming peers. We found that older students, bisexual youth, Latino youth, and youth who experienced school violence perceived their gender nonconforming male peers to be less safe. Similarly, we found that older students and students who experienced school violence and harassment due to gender nonconformity perceived their gender nonconforming female peers to be less safe. At the school-level, we found that when schools included lesbian, gay, bisexual, transgender, and queer (LGBTQ) issues in the curriculum and had a Gay-Straight Alliance, students perceived their schools as safer for gender nonconforming male peers.

Transgender youth experience negative school environments and may not benefit directly from interventions defined to support Lesbian, Gay and Bisexual (LGB) youth. This study utilized a multi-method approach to consider the issues that transgender students encounter in school environments. Using data from two studies, survey data (total n = 2260, 68 transgender youth) from study 1 and focus groups (n = 35) from study 2, we examine transgender youth's experience of school harassment, school strategies implemented to reduce harassment, the protective role of supportive school personnel, and individual responses to harassment, including dropping out and changing schools. In both studies, we found that school harassment due to transgender identity was pervasive, and this harassment was negatively associated with feelings of safety. When schools took action to reduce harassment, students reported greater connections to school personnel. Those connections were associated with greater feelings of safety. The indirect effects of school strategies to reduce harassment on feelings of safety through connection to adults were also significant. Focus group data illuminate specific processes schools can engage in to benefit youth, and how the youth experience those interventions.

A case of enterococcal meningitis in a toddler is presented. The organism was highly resistant to all drugs previously used for pediatric Gram-positive meningitis. She was successfully treated with intraventricular and intravenous daptomycin and intravenous tigecycline. The organism was characterized as a member of CC17, a notorious emerging nosocomial clone of Enterococcus faecium.

The E-cadherin receptor CD103 (alphaEbeta7-integrin) is expressed on specific populations of pulmonary dendritic cells (DC) and T cells. However, CD103 function in the lung is not well understood. Matrilysin (MMP-7) expression is increased in lung injury and cleaves E-cadherin from injured lung epithelium. Thus, to assess matrilysin effects on CD103-E-cadherin interactions in lung injury, wild-type, CD103(-/-), and Mmp7(-/-) mice, in which E-cadherin isn't cleaved in the lung, were treated with bleomycin or bleomycin with nFMLP to reverse the defect in acute neutrophil influx seen in Mmp7(-/-) mice. Pulmonary CD103(+) DC were significantly increased in injured wild-type compared with Mmp7(-/-) mice, and CD103(+) leukocytes showed significantly enhanced interaction with E-cadherin on injured wild-type epithelium than with Mmp7(-/-) epithelium in vitro and in vivo. Bleomycin-treated CD103(-/-) mice had persistent neutrophilic inflammation, increased fibrosis, and increased mortality compared with wild-type mice, a phenotype that was partially recapitulated in bleomycin/nFMLP-treated Mmp7(-/-) mice. Soluble E-cadherin increased IL-12 and IL-10 and reduced IL-6 mRNA expression in wild-type bone marrow-derived DC but not in CD103(-/-) bone marrow-derived DC. Similar mRNA patterns were seen in lungs of bleomycin-injured wild-type, but not CD103(-/-) or Mmp7(-/-), mice. In conclusion, matrilysin regulates pulmonary localization of DC that express CD103, and E-cadherin cleavage may activate CD103(+) DC to limit inflammation and inhibit fibrosis.

Obliterative bronchiolitis (OB) is the histopathological finding in chronic lung allograft rejection. Mounting evidence suggests that epithelial damage drives the development of airway fibrosis in OB. Tissue inhibitor of metalloproteinase (TIMP)-1 expression increases in lung allografts and is associated with the onset of allograft rejection. Furthermore, in a mouse model of OB, airway obliteration is reduced in TIMP-1-deficient mice. Matrilysin (matrix metallproteinase-7) is essential for airway epithelial repair and is required for the re-epithelialization of airway wounds by facilitating cell migration; therefore, the goal of this study was to determine whether TIMP-1 inhibits re-epithelialization through matrilysin. We found that TIMP-1 and matrilysin co-localized in the epithelium of human lungs with OB and both co-localized and co-immunoprecipitated in wounded primary airway epithelial cultures. TIMP-1-deficient cultures migrated faster, and epithelial cells spread to a greater extent compared with wild-type cultures. TIMP-1 also inhibited matrilysin-mediated cell migration and spreading in vitro. In vivo, TIMP-1 deficiency enhanced airway re-epithelialization after naphthalene injury. Furthermore, TIMP-1 and matrilysin co-localized in airway epithelial cells adjacent to the wound edge. Our data demonstrate that TIMP-1 interacts with matrix metalloproteinases and regulates matrilysin activity during airway epithelial repair. Furthermore, we speculate that TIMP-1 overexpression restricts airway re-epithelialization by inhibiting matrilysin activity, contributing to a stereotypic injury response that promotes airway fibrosis via bronchiole airway epithelial damage and obliteration.

Matrilysin [matrix metalloproteinase 7 (MMP7)] is induced by mucosal injury of many tissues. To assess function of this proteinase, we subjected wild-type and Mmp7(-/-) mice to acute colon injury. When matrilysin expression was increasing, 73% of wild-type mice died, whereas only 32% of Mmp7(-/-) mice succumbed. Although re-epithelialization was delayed in Mmp7(-/-) mice, overall injury did not differ markedly between genotypes. We hypothesized that differences in acute inflammation caused increased mortality in wild-type mice. Indeed, whereas overall neutrophil influx into tissue was similar in wild-type and Mmp7(-/-) mice, their location and extent of migration differed between genotypes. Neutrophils were dispersed throughout the mucosa and within the lumen of wild-type mice, but these leukocytes were largely confined to the submucosa in Mmp7(-/-) mice. The levels of neutrophil chemokines, keratinocyte-derived chemokine and MIP-2, increased in the colon tissue of both genotypes, but these factors were detected only in lumenal lavages of wild-type mice. Our findings indicate that matrilysin mediates beneficial and deleterious effects in response to injury. On one hand, it promotes re-epithelialization, but it also controls the transepithelial influx of neutrophils, which if excessive, can lead to tissue damage.

Airway epithelium is the initial point of host-pathogen interaction in Pseudomonas aeruginosa infection, an important pathogen in cystic fibrosis and nosocomial pneumonia. We used global gene expression analysis to determine airway epithelial transcriptional responses dependent on matrilysin (MMP-7) and stromelysin-2 (MMP-10), two matrix metalloproteinases induced by acute P. aeruginosa pulmonary infection. Extraction of Differential Gene Expression (EDGE) analysis of gene expression changes in P. aeruginosa infected organotypic tracheal epithelial cell cultures from wildtype, Mmp7(-/-), and Mmp10(-/-) mice identified 2,089 matrilysin-dependent and 1,628 stromelysin-2-dependent genes that were differentially expressed. Key node network analysis showed that these MMPs controlled distinct gene expression programs involved in proliferation, cell death, immune responses, and signal transduction, among other host defense processes. Our results demonstrate discrete roles for these MMPs in regulating epithelial responses to pseudomonas infection and show that a global genomics strategy can be used to assess MMP function.