Thèses sur le sujet « Lungs Pathophysiology »

Bibliography: leaves 168-184. The work in this study encompasses oxygen free radical related inflammation in the peripheral lung and in lung cells. Animal and human studies have been used. Methods include cell culture with function studies, protein chemistry, animal and human physiology, and cell and lung structure through histopathology, and various forms of electron microscopy. The work resulting from this thesis has formed an important basis for understanding acute and chronic lung injury.

The cardiopulmonary effects of endotoxin administration (1 microgram/kg) were evaluated in 8-10 week old SPF-derived Yorkshire pigs, both because endotoxemia is a common and important swine problem, and because the pig is a good model for human adult respiratory distress syndrome. Physiological changes included sustained increases in mean pulmonary artery pressure, pulmonary vascular resistance, pulmonary arterial wedge pressure, heart rate, hematocrit, and the arterial partial pressure of carbon dioxide. Transient increases were also observed in central venous pressure and airway pressure. Transient increases, followed by decreases, were observed in mean systemic arterial pressures and systemic vascular resistance. Decreases were seen in cardiac output, cardiac index, arterial partial pressure of oxygen and oxygen saturation. The number of circulating leukocytes, lymphocytes and segmented neutrophils decreased with endotoxin infusion. To investigate the role of airway smooth muscle, bronchial rings were isolated and exposed to contractile agents in tissue baths. A hyperresponsiveness of the third generation bronchi to substance P, carbachol, bradykinin and electric field stimulation was observed. However the increase in response to bradykinin and electric field stimulation were not statistically significant. Histopathology of the lungs demonstrated congestion, hemorrhage and neutrophilic infiltration.
Master of Science

Le travail présenté ici porte sur l’étude de la production et du transport du monoxyde d’azote (NO) dans le poumon humain. Le NO est une molécule dont l’implication dans des processus physiologiques n’a été mis en évidence qu’en 1987. Depuis, il a été démontré que le NO joue de nombreux rôles dans le corps humain. Le NO est un gaz labile (instable) dans les conditions physiologiques, il diffuse très facilement au travers des parois et il a une grande affinité pour l’hémoglobine. La production du NO est liée à 3 isoformes différentes de la protéine appelées synthases du NO ou NO synthases.

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Doctorat en sciences, Spécialisation physique
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Chemoattractant agents play a crucial role in the initiation of immune responses, by regulating the traffic and function of leucocyte populations. Their receptors are therefore considered as potential targets for the development of new therapies in the fields of cancer and inflammatory diseases. ChemR23, a previously orphan receptor discovered in the laboratory, is structurally related to receptors for chemoattractant agents. It is expressed on immature myeloid and plasmacytoid dendritic cells (mDCs and pDCs respectively), as well as on adipocytes, macrophages, NK and endothelial cells. Chemerin, the endogenous ligand of ChemR23, is abundant in various human samples originating from inflammatory diseases, including pleural effusions. Chemerin is secreted as an inactive precursor, prochemerin, and is activated by the removal of six or seven amino-acids from its carboxy-terminus by serine proteases, such as as cathepsin G and elastase. Chemerin acts as a chemoattractant agent of low nanomolar potency for macrophages, immature mDCs and pDCs. It is however more active on pDCs, in line with the higher expression of ChemR23 on these cells. pDCs possess important immunoregulatory properties in lung diseases, and their ability to secrete large amounts of type I interferon (IFN) upon viral infection makes them crucial players in anti-viral immunity.

According to these elements, and to the role of neutrophils in the physiopathology of many inflammatory lung diseases and in the generation of active chemerin, we began in 2007 to study the role of chemerin and its receptor ChemR23 in inflammatory lung diseases. We first characterized the mouse chemerin/ChemR23 system, and described that this system was very similar to the human one, in terms of distribution, pharmacology and functional properties. We then used wild type mice (WT) and mice invalidated for the receptor (ChemR23-/-) in various models of inflammatory lung diseases, including asthma, lung fibrosis, viral pneumonia, and acute lung injury.

Whereas the asthma and lung fibrosis models did not allow to demonstrate a significant role of the chemerin/ChemR23 system (possibly as a result of the lack of production of active chemerin in these models), infection by either the Pneumonia Virus of Mice (PVM), the mouse counterpart of human RSV, or by a murinized H1N1 influenza strain resulted in a significantly higher mortality rate in ChemR23-/- mice as compared to their WT counterparts. Using the PVM-induced pneumonia model, we observed that the excessive mortality of knock-out mice is caused by an inadequate and excessive innate immune response characterized by a massive recruitment of neutrophils to the lungs, associated with a delayed viral clearance and lower type I IFN synthesis. This latter observation suggested an impairment of pDC recruitment, according to the important contribution of pDCs to the production of type I IFNs in viral diseases, and the role of chemerin in the recruitment of these cells. We indeed confirmed a lower recruitment of pDCs in the lung of infected ChemR23-/- mice, as compared to WT mice. However, experiments of adoptive transfert and depletion of pDCs failed to proof a link between impaired pDC recruitment and the excessive morbidity and mortality observed in ChemR23-invalidated mice.

In parallel, we studied the role of the chemerin/ChemR23 system in the control of innate immune responses, by using a model of acute lung injury caused by the intra-tracheal instillation of bacterial lipopolysaccharide (LPS). In this model, administration of recombinant chemerin together with LPS in WT mice resulted in a significant (about 50%) reduction of neutrophil recruitment to both lung parenchyma and airways. Assessment of pro-inflammatory cytokines and chemokines in broncho-alveolar lavage fluids confirmed this anti-inflammatory effect of chemerin, which was ChemR23-dependent, as the inflammatory response of ChemR23-/- mice was unaffected by chemerin. In our hands, chemerin does not modulate macrophage functions, in contrast to data recently published by other groups, attributing anti-inflammatory effects of chemerin or chemerin-derived peptide to the modulation of macrophage activation and phagocytosis. Other hypotheses that could take our observations into account are presently investigated, including an immunomodulatory role of chemerin on lung epithelial or endothelial cells, and/or the ChemR23-dependent recruitment of subtypes of macrophages or other myeloid cells endowed with immunosuppressive properties.

In conclusion, our studies characterized the mouse chemerin/ChemR23 system and highlighted the role of this system in the physiopathology of some inflammatory lung diseases. Our results suggest that the chemerin/ChemR23 system might be considered as a potential therapeutic target for the development of future anti-infectious and anti-inflammatory therapies, particularly for viral pneumonia, which represent a major public health problem, as well as for acute respiratory distress syndrome (ARDS) following severe acute lung injuries.

Les agents chimioattractants jouent un rôle fondamental dans l’initiation des réponses immunes en régulant le trafic et la fonction des populations leucocytaires. Leurs récepteurs constituent dès lors des cibles d’intérêt pour le développement de traitements contre les maladies inflammatoires et le cancer. Le laboratoire d’accueil a identifié le récepteur ChemR23, exprimé à la surface des cellules dendritiques myéloïdes (mDCs) et plasmacytoïdes (pDCs) immatures, des macrophages, des cellules NK, des adipocytes, et des cellules endothéliales. Le ligand endogène du récepteur ChemR23, la chémérine, est présent en abondance dans divers échantillons pathologiques d’origine inflammatoire. La chémérine est produite sous la forme d'un précurseur inactif, la prochémérine, qui nécessite pour devenir active le clivage protéolytique de six ou sept acides aminés à son extrémité carboxy-terminale. La chémérine induit le chimiotactisme des macrophages et des DCs immatures, et en particulier des pDCs immatures en accord avec l’expression plus importante de ChemR23 par les pDCs. Les pDCs jouent un rôle immunorégulateur important en pathologie pulmonaire, en particulier dans la physiopathologie des pneumonies virales, par leur capacité à produire d’importantes quantités d’interféron (IFN) de type I.

Compte tenu de ces éléments et du rôle des polynucléaires neutrophiles dans de nombreuses pathologies pulmonaires, ainsi que dans la génération de chémérine active à partir de son précurseur, nous avons débuté en octobre 2007, l’étude du rôle de la chémérine et de son récepteur ChemR23 dans le contrôle des pathologies pulmonaires inflammatoires. Nous avons tout d’abord caractérisé le système chémérine/ChemR23 chez la souris et avons montré que ce système présentait des caractéristiques similaires à celles décrites chez l’homme, en termes de distribution, de pharmacologie et de propriétés fonctionnelles.

Ensuite, nous avons comparé des souris sauvages et invalidées pour le récepteur ChemR23 (ChemR23-/-) dans divers modèles de pathologies pulmonaires. Les modèles d’asthme et de fibrose pulmonaire induite par instillation de bléomycine ou de silice n’ont pas permis de mettre en évidence un rôle important du couple chémérine/ChemR23, peut-être en raison de l’absence de génération de forme active de chémérine dans ces modèles. En revanche, l’administration de deux agents viraux différents, le PVM (Pneumonia Virus of Mice), l’équivalent murin du RSV humain, et un virus de l’influenza H1N1 murinisé, a résulté en un taux de mortalité 40% plus élevé pour les souris ChemR23-/- par rapport à leurs homologues sauvages. En utilisant le modèle de pneumonie induite par le PVM, nous avons montré que cette différence de mortalité est causée par une réponse immune inappropriée et excessive, associée à une réduction de l’élimination du virus, ainsi qu’à un déficit de synthèse d’IFN de type I. Les pDCs, dans un contexte d’infection virale, sont capables de synthétiser d’importantes quantités d’IFN de type I, et nous avons mis en évidence un déficit relatif de recrutement en pDCs chez les souris ChemR23-/- infectées. Néanmoins, les expériences de transfert adoptif et de déplétion de pDCs n’ont pas permis de lier ce défaut de recrutement à l’excès de morbidité et de mortalité observé chez les souris ChemR23-/- infectées.

En parallèle, le rôle de ce couple ligand-récepteur dans le contrôle des réponses immunitaires innées a été étudié dans un modèle de pneumopathie aiguë induite par instillation intra-trachéale de lipopolysaccharide (LPS). Dans ce modèle, l’administration simultanée de chémérine recombinante avec le LPS entraîne chez les souris sauvages une diminution significative (environ 50%) du nombre de polynucléaires neutrophiles recrutés dans les voies aériennes et dans le parenchyme pulmonaire, ainsi qu’une importante diminution de synthèse de cytokines pro-inflammatoires. Cet effet anti-inflammatoire de la chémérine est dépendant de ChemR23, et ne semble pas être secondaire à un effet de la chémérine sur l’activation des macrophages, contrairement à certaines données publiées récemment par d’autres groupes. D’autres hypothèses permettraient cependant de prendre en compte ces observations, notamment un effet de la chémérine sur les cellules épithéliales et/ou endothéliales pulmonaires, ainsi que sur le recrutement de sous-populations de macrophages ou d’autres cellules myéloïdes possédant des propriétés immunosuppressives. Des expériences complémentaires ont été initiées afin de tester ces hypothèses.

En conclusion, après avoir caractérisé le système chémérine/ChemR23 chez la souris, nos études ont permis de mettre en évidence le rôle de ce couple ligand/récepteur dans la physiopathologie de certaines pneumopathies inflammatoires, ouvrant ainsi de nouvelles perspectives thérapeutiques, en particulier pour le traitement des pneumopathies virales, qui constituent un problème de santé publique majeur, ainsi que des syndromes de détresse respiratoire aiguë (ARDS).
Doctorat en Sciences médicales
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Amongst respiratory diseases, inflammatory lung diseases constitute a major part of public

health problem. As a consequence, investigating the immune mechanisms that contribute to

the pathogenesis of these diseases is essential to identify candidate targets for the

development of new therapeutic drugs. Furthermore, over the past 20 years, the growing awareness

that purinergic signalling events shape the immune and inflammatory responses to infection and

allergic reactions warranted the development of animal models to assess their importance in vivo in

acute lung injury and chronic airway diseases. The field of purinergic inflammation formulated the

unifying concept that ATP is released as a «danger signal» to induce inflammatory responses upon

binding purinergic receptors.

According to these elements, we began in 2007 to evaluate lung inflammation in mice deficient for

the P2Y2 purinergic receptor in TH2 and TH1 models. The most convincing evidence that the P2Y2

receptor is engaged during alarm situations comes from studies related to cystic fibrosis and asthma.

Indeed, chronic respiratory diseases are commonly associated with elevated airway ATP

concentrations, as reported in cystic fibrosis, but also in idiopathic pulmonary fibrosis and chronic

obstructive pulmonary disease (COPD) patients, and they are raised by allergens in asthmatic

patients.

First, we demonstrated a significant role of the P2Y2R in a TH2-ovalbumin(OVA)-induced asthma

model. We observed that eosinophil accumulation, a distinctive feature of lung allergic inflammation,

was defective in OVA-treated P2Y2-deficient mice compared with OVA-treated wild type animals.

Interestingly, the upregulation of VCAM-1 was lower on lung endothelial cells of OVA-treated P2Y2

knockout mice compared with OVA-treated wild type animals. Adhesion assays demonstrated that

the action of UTP on leukocyte adhesion through the regulation of endothelial VCAM-1 was

abolished in P2Y2-deficient lung endothelial cells. Additionally, the level of soluble VCAM-1, reported

as an inducer of eosinophil chemotaxis, was strongly reduced in the bronchoalveolar lavage fluid of

P2Y2-deficient mice.

Secondly, we studied the consequences of P2Y2R loss in lung inflammation initiated after pneumonia

virus of mice (PVM) infection in collaboration with the group of Pr. Daniel Desmecht (ULg). We

demonstrated here that P2Y2

-/-

mice display a severe increase in morbidity and mortality rate in

response to PVM. Lower survival of P2Y2

-/-

mice was not correlated with excessive inflammation

despite the higher level of neutrophil recruiters in their broncho-alveolar fluids. Interestingly, we

observed lower numbers of dendritic cells, CD4

+

T cells and CD8

+

T cells in P2Y2

-/-

mice compared to

P2Y2

+/+

infected lungs. Lower level of IL-12 and higher level of IL-6 in broncho-alveolar fluid support

an inhibition of Th1 response in P2Y2

-/-

mice. Quantification of DC recruiter expression revealed

comparable IP-10 and MIP-3&
Doctorat en Sciences biomédicales et pharmaceutiques
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La pneumopathie interstitielle (PI) est devenue la principale cause de décès de la sclérodermie systémique (ScS). Au cours de PI, l’activation immunitaire déclenche une forte production du monoxyde d’azote (NO) et l’augmentation de la concentration de NO dans l’air expiré des patients atteints de ScS avec PI suggère que cette méthode pourrait détecter précocement l’alvéolite, afin de traiter à temps la PI pour éviter son évolution vers la fibrose pulmonaire. En utilisant le modèle à deux compartiments séparant le NO alvéolaire (CANO) du NO bronchique, nous avons montré que la CANO est : (1) augmentée chez les patients atteints de ScS comparativement aux volontaires sains; (2) associée à l’alvéolite et (3) corrélée à la sévérité de la PI. De plus, une valeur de CANO = 10,8 ppb permettait d’affirmer la présence de la PI et une valeur = 3,8 ppb, d’écarter l’existence d’une PI avec une valeur prédictive= 95%. Le modèle bi-compartimenté néglige la distribution arborisée des voies aériennes et la diffusion axiale du NO, que prend en compte le nouveau « modèle de la trompette ». Les résultats de CANO des 2 méthodes sont comparables (rho=0,98, p<0.001). Enfin, La capacité des sérums à induire la prolifération des fibroblastes pulmonaires et sa conversion en myofibroblaste est augmentée chez les patients atteints de ScS avec une CANO > 5ppb par rapport à celle des patients atteints de ScS qui ont une CANO = 5 ppb et à celle des volontaires sains. Nos résultats suggèrent une relation possible entre l’inflammation alvéolaire et la fibrose pulmonaire au cours de la ScS
Interstitial lung disease (ILD) has become the main cause of death in systemic sclerosis (SSc). In ILD, immune activation leads to strong nitric oxide (NO) output by inducible NO synthase. Increased the whole fractional rate of NO in exhaled air has been reported in SSc patients with ILD and suggested that exhaled NO can be an accurate none-invasive marker of early alveolar inflammation in order to initiate in time treatment. The two compartment-model method partitioned exhaled NO into alveolar concentration (CANO) and conducting airway flux, We hypothesized that overproduction of NO in the lung eventually leads to ILD in SSc. We have found that CANO is significantly increased in SSc patients as compared with healthy controls. We have also demonstrated that high levels of CANO were related to alveolitis and the severity of ILD in SSc. Moreover, we have found that ILD could be ruled in (positive predictive value > 95%) when CANO = 10.8 ppb, and ruled out when CANO values = 3.8 ppb (negative predictive value > 95%). The two-compartment model neglected the trumpet shape of airway tree and the axial diffusion of NO that the advanced “trumpet model” takes account. We have found that CANO levels assessed by the two models were comparable (rho=0,98, p<0.001). Finally, we have found that the serum ability to induce lung fibroblast proliferation and myofibroblast transition was increased in SSc patients with high levels of CANO (>5ppb) as compared to SSc patients with low levels of CANO (=5ppb) and healthy controls. Our findings suggest a possible link between alveolar inflammation, and lung fibrosis in SSc. 1624 caractères avec espace

A inflamação pulmonar pode variar de acordo com o sitio primário da injuria e poder ser afetado pelo estresse mecânico gerado pela ventilação mecânica. (VM) Objetivos: estudar as eventuais diferenças na reposta pulmonar e sistêmica na lesão pulmonar aguda pulmonar (LPA P ) e extra pulmonar (LPA Exp) após ventilação mecânica. Métodos: Camundongos BALB/c foram divididos em doze grupos. Os grupos controle pulmonar (CP) e extra pulmonar (C Exp) receberam solução salina (SAL) ou Lipopolissacarideo (LPS) via intratraqueal (IT) ou intraperitoneal (IP) respectivamente. Os grupos foram submetidos ou não a simples manobra de pressurização (SMP) até 45 cm H2O. Resultados: Os grupos LPAP e LPAExp não ventilados apresentaram o mesmo nível de inflamação; uma diferença estatisticamente significativa na densidade de células inflamatórias foi observada no grupo LPA P VM (3,84±1,28 cels/2) comparado ao grupo LPA Exp VM ((1,75±0,14 cels/2), p=0,013. O mesmo foi observado na LPA P SMP (2,92±0,44 cels/2) comparado ao LPA Exp SMP (1,46±0,23 cels/2), p<0,0001. LPAP mostrou estatisticamente significante aumento no El (56,19 ± 12,26 cm H2O) em comparação ao LPA Exp SMP (26,88 ± 36,38 cm H2O) após SMP (p = 0,029). Nenhuma diferença estatisticamente significante foi observada no estresse oxidativo no rim. Conclusão: Observamos um padrão diferente da resposta inflamatória e mecânica pulmonar comparando LPA pulmonar e extra-pulmonar submetido à ventilação mecânica de curto prazo. Embora a ventilação mecânica represente uma ferramenta essencial para estabilizar o paciente critico, é necessário individualizar a abordagem do tratamento ventilatório
Lung inflammation may vary according to the primary site of injury and may be affected by the mechanical stress generated by mechanical ventilation (MV). Objectives: to address possible differences in lung and systemic responses in pulmonary and extra pulmonary ALI after mechanical ventilation. Methods: BALB/c mice were divided in twelve groups of six animals. In pulmonary and extrapulmonary control or ALI groups received either saline or LPS (intratracheally instilled or intraperitoneally injected), respectively. Ventilated groups were either recruited or not with a single recruitment maneuver (SRM) reaching 45 cm H2O. Results: At baseline ALI P and ALI EXP non ventilated groups presented the same level of inflammation; a statistically significant difference in density of inflammatory cells was noted in ALI P MV (3,84±1,28 cells/2) compared to ALI EXP MV (1,75±0,14 cells/2), p=0,013. The same was observed in ALI P SRM (2,92±0,44 cells/2) compared to ALI EXP SRM (1,46±0,23 cells/2) ventilated groups (p<0,0001). ALI P showed a statistically significant increase in El (56,19 ± 12,26 cm H2O) in comparison to ALI EXP (26,88 ± 36,38 cm H2O) after SRM (p = 0,029). No statistical differences were observed in kidney oxidative stress. Conclusion: We observed a different pattern of response in lung inflammation and mechanics comparing pulmonary and extra pulmonary ALI, submitted to short term mechanical ventilation. Although mechanical ventilation represents a fundamental tool to stabilize critical patients, it is essential to individualize the approach of the ventilatory treatment

Bibliography: leaves 168-184.
184 leaves : ill. (chiefly col.) ; 30 cm.
The work in this study encompasses oxygen free radical related inflammation in the peripheral lung and in lung cells. Animal and human studies have been used. Methods include cell culture with function studies, protein chemistry, animal and human physiology, and cell and lung structure through histopathology, and various forms of electron microscopy. The work resulting from this thesis has formed an important basis for understanding acute and chronic lung injury.
Thesis (Ph.D.)--University of Adelaide, Dept. of Pathology, 2000

Liu, Yi.
Thesis Ph.D. Chinese University of Hong Kong 2015.
Includes bibliographical references (leaves 154-175).
Abstracts also in Chinese.
Title from PDF title page (viewed on 25, October, 2016).

Indiana University-Purdue University Indianapolis (IUPUI)
Rationale: CD55 down-regulation on airway epithelium correlates with local complement activation observed in hypoxia-associated pulmonary diseases. Therefore, we hypothesized that induction of hypoxia inducible factor 1 alpha (HIF-1α) in hypoxic airway epithelium, mediates CD55 down-regulation. Methods: Chetomin and HIF-1α siRNA inhibited HIF-1α in hypoxic SAECs (1% O2), and mice lungs (10% O2). DMOG mediated HIF-1α stabilization in normoxic SAECs and mice lungs (21% O2). Transduction of SAECs with AdCA5 also stabilized HIF-1α. CD55 and CA9 transcripts were measured by RT-PCR. CD55 and HIF-1α protein expression was assessed by western blots. In vivo, immunohistochemistry (IHC) confirmed CD55 and HIF-1α expression. C3a and C5a levels in bronchoalveolar lavage fluid (BALF) were measured by ELISA. Results: HIF-1α was induced in 6 hour hypoxic SAECs (p<0.05), but CD55 transcripts were repressed (p<0.05). CD55 protein was down-regulated by 72 hours (p<0.05). CA9 transcripts were elevated by 48 -72 hours (p<0.05 and p<0.01, respectively). In vivo, CD55 transcripts and protein were down- regulated by 24 hours post-hypoxia (p<0.01) which corresponded to complement activation (p<0.05) in BALF. However, CA9 was increased (p<0.01). Chetomin (100nM) treatment in 6 hour hypoxic SAECs, recovered CD55 transcripts (p<0.01) and protein (p<0.05), but down-regulated CA9 (p<0.05). Similarly, in vivo chetomin (1mg/ml) treatment recovered CD55 protein (p<0.01) and down-regulated CA9 (p<0.01). Silencing HIF-1α (50nM) in hypoxic SAECs restored CD55 transcripts by 6 hours (p<0.05), and protein expression by 24 hours (p<0.05). However, CA9 was repressed (p<0.01). In vivo silencing of HIF-1α (50µg) restored CD55 protein expression (p<0.05) but down-regulated CA9 (p<0.05). Stabilizing HIF-1α in normoxic SAECs via DMOG (1µM), down-regulated CD55 transcripts and protein (p<0.01), but increased CA9 within 6-24 hours (p<0.05 and p<0.01, respectively). HIF-1α induction by DMOG (1mg/ml) in normoxic mice lungs down-regulated CD55 transcripts (p<0.01) and protein (p<0.01), but increased CA9 (p<0.05). Induction of HIF-1α in AdCA5 (50 PFUs/cell) transduced normoxic SAECs, resulted in CD55 protein down-regulation (p<0.05), but increased CA9 (p<0.001). Conclusions: HIF-1α down-regulates CD55 on airway epithelium. Targeting this mechanism may be a potential therapeutic intervention for attenuating complement activation in hypoxic pulmonary diseases.

博士
國立陽明大學
生理學研究所
101
Acute phase of lung inflammatory diseases, such as acute lung injury (ALI) and acute respiratory distress syndrome (ARDS), is usually accompanied with disruption of alveolar-capillary barrier and induction of inflammatory-related cytokines and chemokines. Glucosamine, a natural occurring amino monosaccharide highly concentrated in connective tissues, is a joint supplement widely used in the treatment of arthritis. Recently, glucosamine has begun to be considered the potential anti-inflammatory properties to treat the other inflammation disease and anti-cell proliferation abilities to affect cell physiological activities. Nevertheless, the roles of glucosamine in lung pathology and physiology as well as the involved molecular mechanisms have not been well characterized. Our study aims to clarify how glucosamine plays an anti-inflammatory role in response to bacterial endotoxin and the additional possible toxicity on cellular proliferation. Using rat lung inflammation model caused by intratracheal instillation of LPS, pulmonary edema and polymorphonuclear neutrophil (PMN) infiltration, as well as the production of inflammatory cytokines (TNF-alpha, IL-1 beta and IFN-gamma), chemokines (CINC-1, MIP-2 and MCP-1) and nitric oxide (NO)/inducible nitric oxide synthase (iNOS) in alveolar space and/or lung parenchyma, were noted to be mitigated by glucosamine. Using a rat alveolar epithelial cell line L2, cytokine mixture (cytomix)-regulated expression of chemokines (CINC-1 and MIP-2) and NO/iNOS was also suppressed by glucosamine. In addition, we further to prove that glucosamine-reduced NO/iNOS is through down-regulation of NF-kappaB signaling cascades. Furthermore, we also uncovered that glucosamine suppressed cellular proliferation, and induced cell cycle arrest and late apoptosis in human alveolar epithelial cells (A549) and bronchial epithelial cells (HBECs). Moreover, we found an inhibitory effect on phosphorylation of retinoblastoma (Rb) protein and modification on expression of cell cycle-related regulators (p21, p27, p53 and HO-1). In addition, glucosamine attenuated p21 protein stability via the proteasomal proteolytic pathway, as well as inducing p21 nuclear accumulation. Taken together, glucosamine appears to act as an anti-inflammatory role in LPS-induced lung inflammation, at least in part, by targeting to the NF-kappaB signaling pathway, and an inhibitory molecule on cell proliferation through apoptosis and cell cycle disturbance with a halt at G0/G1 phase, which is partly mediated by the reduction in Rb phosphorylation together with modulation of p21, p53 and HO-1 expression, and nuclear p21 accumulation.

Indiana University-Purdue University Indianapolis (IUPUI)
The patients with Cystic fibrosis (CF), an inherent genetic disorder, suffer from chronic bacterial infection in the lung. In CF, modification of epithelial cells leads to alteration of the lung environment, such as inhibition of ciliary bacterial clearance and accumulation of thickened mucus in the airways. Exploiting these conditions, opportunistic pathogens like Pseudomonas aeruginosa cause lifelong persistent infection in the CF lung by forming into antibiotic-resistant aggregated communities called biofilms. Airway infections as well as inflammation are the two major presentations of CF lung disease. P. aeruginosa strains isolated from CF lungs often contain mutations in the mucA gene, and this mutation results in higher level expression of bacterial polysaccharides and toxic lipoproteins. In a previous work, we have found a putative lipoprotein gene (PA4326) which is overexpressed in antibiotic-induced biofilm formed on cultured CF-derived airway cells. In the current work, we speculated that this particular putative lipoprotein affects cellular cytotoxicity and immune-stimulation in the epithelial cells. We found that mutation of this gene (ΔPA4326) results in reduced airway cell killing without affecting other common virulence factors.Moreover, we observed that this gene was able to stimulate secretion of the proinflammatory cytokine IL-8 from host cells. Interestingly, we also found that ΔPA4326 mutant strains produced less pyocyanin exotoxin compared to the wild type. Furthermore, our results suggest that PA4326 regulates expression of the pyocyanin biosynthesis gene phzM, leading to the reduced pyocyanin phenotype. Overall, these findings implicate PA4326 as a virulence factor in Pseudomonas aeruginosa. In the future, understating the molecular interplay between the epithelial cells and putative lipoproteins like PA4326 may lead to development of novel anti-inflammatory therapies that would lessen the suffering of CF patients.