Plasminogen Activator Inhibitor-1 in Cigarette Smoke Exposure and Influenza A Virus Infection-Induced Lung Injury

Parenchymal lung inflammation and airway and alveolar epithelial cell apoptosis are associated with cigarette smoke exposure (CSE), which contributes to chronic obstructive pulmonary disease (COPD). Epidemiological studies indicate that people exposed to chronic cigarette smoke with or without COPD are more susceptible to influenza A virus (IAV) infection. We found increased p53, PAI-1 and apoptosis in AECs, with accumulation of macrophages and neutrophils in the lungs of patients with COPD. In Wild-type (WT) mice with passive CSE (PCSE), p53 and PAI-1 expression and apoptosis were increased in AECs as was lung inflammation, while those lacking p53 or PAI-1 resisted AEC apoptosis and lung inflammation. Further, inhibition of p53-mediated induction of PAI-1 by treatment of WT mice with caveolin-1 scaffolding domain peptide (CSP) reduced PCSE-induced lung inflammation and reversed PCSE-induced suppression of eosinophil-associated RNase1 (EAR1). Competitive inhibition of the p53-PAI-1 mRNA interaction by expressing p53-binding 3\u27UTR sequences of PAI-1 mRNA likewise suppressed CS-induced PAI-1 and AEC apoptosis and restored EAR1 expression. Consistent with PCSE-induced lung injury, IAV infection increased p53, PAI-1 and apoptosis in AECs in association with pulmonary inflammation. Lung inflammation induced by PCSE was worsened by subsequent exposure to IAV. Mice lacking PAI-1 that were exposed to IAV showed minimal viral burden based on M2 antigen and hemagglutination analyses, whereas transgenic mice that overexpress PAI-1 without PCSE showed increased M2 antigen and inflammation after IAV infection. These observations indicate that increased PAI-1 expression promotes AEC apoptosis and exacerbates lung inflammation induced by IAV following PCSE

Immune response of bighorn sheep to Mannheimia haemolytica

Bighorn sheep (BHS; Ovis canadensis) are more susceptible to Mannheimia haemolytica-caused pneumonia, than domestic sheep (DS; Ovis aries). The objective of this study was to elucidate the basis for enhanced susceptibility of BHS, and explore potential strategies to prevent pneumonia in BHS. I hypothesized that enhanced lung pathology in BHS is due to inadequate clearance of M. haemolytica from the lungs. To test this hypothesis, M. haemolytica was inoculated intra-tracheally into groups of BHS and DS that were necropsied at 4, 12, and 18 hours post-inoculation (hpi). DS completely cleared the bacteria from the lungs by 18 hpi, whereas BHS had large number of bacteria still remaining in the lungs. Furthermore, bronchoalveolar lavage fluid from BHS had significantly lower titers of neutralizing antibodies to leukotoxin, the critical virulence factor of M. haemolytica. These findings suggested that enhanced lung pathology in BHS is likely due to inadequate clearance from the lungs, which, at least partly, is due to low titer of leukotoxin-neutralizing antibodies. In another study, serine protease inhibitor B1 of BHS and DS was cloned and expressed to facilitate future studies on the role of protease-anti-protease imbalance in enhanced susceptibility of BHS to M. haemolytica-caused pneumonia.M. haemolytica are more frequently isolated from nasopharynx of DS than that of BHS. Furthermore, most DS isolates are leukotoxin-positive whereas most BHS isolates are leukotoxin-negative, which is likely responsible for the negligibly low titers of leukotoxin-neutralizing antibodies in BHS. A `proof-of-concept' study was designed to determine whether repeated immunization will protect BHS against M. haemolytica challenge. Four BHS were repeatedly inoculated with a vaccine prepared with M. haemolytica A1, A2, and Bibersteinia trehalosi T10 culture supernatant. Upon subsequent challenge with M. haemolytica, all four vaccinated animals survived while all four un-vaccinated animals died within two days, suggesting that BHS are capable of mounting protective immune response against M. haemolytica. This notion was confirmed by another study that showed that MHC class II diversity in BHS is comparable to that of DS. Therefore, induction of immunity to M. haemolytica, particularly to its leukotoxin, is likely to protect BHS against pneumonia caused by this organism

A Review of Selected IBD Biomarkers: From Animal Models to Bedside

Inflammatory bowel disease (IBD) is a dysregulated inflammatory condition induced by multiple factors. The etiology of IBD is largely unknown, and the disease progression and prognosis are variable and unpredictable with uncontrolled disease behavior. Monitoring the status of chronic colitis closely is challenging for physicians, because the assessment of disease activity and severity require invasive methods. Using laboratory biomarkers may provide a useful alternative to invasive methods in the diagnosis and management of IBD. Furthermore, patients with ulcerative colitis or Crohn’s disease are also at risk of developing cancer. Annual colonoscopies can help lower the risk for developing colorectal cancer. However, laboratory biomarkers may also be helpful as non-invasive indicators in predicting treatment responses, improving prognosis, and predicting possible tumors. This review addresses selected laboratory biomarkers (including ANCA, chitinase 3-like 1, S100A12/RAGE, calprotectin, and TNF/TNFR2), which are identified by utilizing two well-accepted animal models of colitis, dextran sodium sulfate-induced and T cell receptor alpha knockout colitis models. In addition to being useful for monitoring disease severity, these biomarkers are associated with therapeutic strategies. The factors may regulate the initiation and perpetuation of inflammatory factors in the gut

A Review of Selected IBD Biomarkers: From Animal Models to Bedside

Inflammatory bowel disease (IBD) is a dysregulated inflammatory condition induced by multiple factors. The etiology of IBD is largely unknown, and the disease progression and prognosis are variable and unpredictable with uncontrolled disease behavior. Monitoring the status of chronic colitis closely is challenging for physicians, because the assessment of disease activity and severity require invasive methods. Using laboratory biomarkers may provide a useful alternative to invasive methods in the diagnosis and management of IBD. Furthermore, patients with ulcerative colitis or Crohn’s disease are also at risk of developing cancer. Annual colonoscopies can help lower the risk for developing colorectal cancer. However, laboratory biomarkers may also be helpful as non-invasive indicators in predicting treatment responses, improving prognosis, and predicting possible tumors. This review addresses selected laboratory biomarkers (including ANCA, chitinase 3-like 1, S100A12/RAGE, calprotectin, and TNF/TNFR2), which are identified by utilizing two well-accepted animal models of colitis, dextran sodium sulfate-induced and T cell receptor alpha knockout colitis models. In addition to being useful for monitoring disease severity, these biomarkers are associated with therapeutic strategies. The factors may regulate the initiation and perpetuation of inflammatory factors in the gut

Delivery of GM-CSF to Protect against Influenza Pneumonia.

Since adaptive immunity is thought to be central to immunity against influenza A virus (IAV) pneumonias, preventive strategies have focused primarily on vaccines. However, vaccine efficacy has been variable, in part because of antigenic shift and drift in circulating influenza viruses. Recent studies have highlighted the importance of innate immunity in protecting against influenza.Granulocyte-macrophage colony stimulating factor (GM-CSF) contributes to maturation of mononuclear phagocytes, enhancing their capacity for phagocytosis and cytokine production.Overexpression of granulocyte macrophage-colony stimulating factor (GM-CSF) in the lung of transgenic mice provides remarkable protection against IAV, which depends on alveolar macrophages (AM). In this study, we report that pulmonary delivery of GM-CSF to wild type young and aged mice abrogated mortality from IAV.We also demonstrate that protection is species specific and human GM-CSF do not protect the mice nor stimulates mouse immunity. We also show that IAV-induced lung injury is the culprit for side-effects of GM-CSF in treating mice after IAV infection, and introduce a novel strategy to deliver the GM-CSF to and retain it in the alveolar space even after IAV infection

Boosting efferocytosis in alveolar space using BCG vaccine to protect host against influenza pneumonia

<div><p>Efferocytosis by alveolar phagocytes (APs) is pivotal in maintenance of lung homeostasis. Increased efferocytosis by APs results in protection against lethal acute lung injury due to pulmonary infections whereas defective efferocytosis by APs results in chronic lung inflammation. In this report, we show that pulmonary delivery of Bacillus Calmette-Guerin (BCG) significantly enhances efferocytosis by APs. Increased efferocytosis by APs maintains lung homeostasis and protects mice against lethal influenza pneumonia. Intranasally treated wild type C57Bl/6 (WT) mice with BCG showed significant increase in APs efferocytosis in vivo compared to their PBS-treated counterparts. All BCG-treated WT mice survived lethal influenza A virus (IAV) infection whereas all PBS-treated mice succumbed. BCG-induced resistance was abrogated by depleting AP prior to IAV infection. BCG treatment increased uptake, and digestion/removal of apoptotic cells by APs. BCG significantly increased the expression of TIM4 on APs and increased expression of Rab5 and Rab7. We demonstrated that increased efferocytosis by APs through pulmonary delivery of BCG initiated rapid clearance of apoptotic cells from the alveolar space, maintained lung homeostasis, reduced inflammation and protected host against lethal IAV pneumonia.</p></div

A Multivalent Mannheimia-Bibersteinia Vaccine Protects Bighorn Sheep against Mannheimia haemolytica Challenge

Bighorn sheep (BHS) are more susceptible than domestic sheep (DS) to Mannheimia haemolytica pneumonia. Although both species carry M. haemolytica as a commensal bacterium in the nasopharynx, DS carry mostly leukotoxin (Lkt)-positive strains while BHS carry Lkt-negative strains. Consequently, antibodies to surface antigens and Lkt are present at much higher titers in DS than in BHS. The objective of this study was to determine whether repeated immunization of BHS with multivalent Mannheimia - Bibersteinia vaccine will protect them upon M. haemolytica challenge. Four BHS were vaccinated with a culture supernatant vaccine prepared from M. haemolytica serotypes A1 and A2 and Bibersteinia trehalosi serotype T10 on days 0, 21, 35, 49, and 77. Four other BHS were used as nonvaccinated controls. On the day of challenge, 12 days after the last immunization, the mean serum titers of Lkt-neutralizing antibodies and antibodies to surface antigens against M. haemolytica were 1:160 and 1:4,000, respectively. Following intranasal challenge with M. haemolytica A2 (1 × 10 5 CFU), all four control BHS died within 48 h. Necropsy revealed acute fibrinonecrotic pneumonia characteristic of M. haemolytica infection. None of the vaccinated BHS died during the 8 weeks postchallenge observation period. Radiography at 3 weeks postchallenge revealed no lung lesions in two vaccinated BHS and mild lesions in the other two, which resolved by 8 weeks postchallenge. These results indicate that if BHS can be induced to develop high titers of Lkt-neutralizing antibodies and antibodies to surface antigens, they are likely to survive M. haemolytica challenge which is likely to reduce the BHS population decline due to pneumonia

Intranasal treatment with BCG protects mice against lethal influenza infection.

<p>WT mice (9 per group) were treated with either PBS or BCG (either intranasally or subcutaneously), and all mice were infected with a lethal dose (2 LD50) of influenza PR8 virus. Weight loss (A) and mortality (B) were recorded daily. (C)Different groups of mice were treated as for panels A and B. Three and 7 days after influenza infection, mice were sacrificed, lung homogenates were generated and virus load was measured. Depicted data are average of 5 mice per group and error bars show SEM. NS = Not significant. (D) BAL cells from a group of BCG- and PBS-treated mice prior to and after IAV infection were quantified. Depicted data are mean of 5 mice per group. Error bars show SEM. (E-F) <b>Depletion of APs abrogated BCG-mediated protection against lethal influenza infection.</b> Mice were intranasally treated with BCG and 24 hrs prior to influenza PR8 infection (2LD50) they were treated with either liposomal clodronate to deplete APs or PBS-liposome as control. Infected mice were monitored for (E) weight loss and (F) mortality. Mean of weight loss with SEMs are depicted. n = 5. DPI: Days Post Infection.</p