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DMHMPC Inhibits Invasiveness Activity of Human Lung Cancer Cells A549Lai,, Yu-Chan 09 September 2008 (has links)
Lung cancer is the leading cause of death in Taiwan cancer patients. The cancer cells are capable of spreading by metastasis and invasion. When tumors spread to distant parts of the body, it is difficult to treat by surgery. In this study, we discovered the novel anti-invasion drugs DMHMPC and DE-DMPC that can inhibit the metastasis and invasion of human lung cancer cell A549. From screening of a chemical library of 420 small molecule compounds using Boyden chamber and MTT assay, the compound DMHMPC and DE-DMPC showed the inhibitory activity toward the invasiveness but not proliferation in human lung cancer cell A549. The results of wound healing assay also showed that DMHMPC and DE-DMPC inhibited the motility of A549 in a dose dependent manner. Moreover, the results of growth curve assay and colony formation assay also showed that DMHMPC and DE-DMPC are not effect proliferation in A549. Together, these results suggested that DMHMPC and DE-DMPC could be the potential drugs to inhibit the invasion of cancer cells that may lead to the new avenue of the cancer prevention therapy.
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Influence of SjGST on the growth and migration of human breast cancer cellsLaio, Tsai-tsen 24 December 2008 (has links)
Glutathione S-transferase (GST) is an essential detoxification enzyme in eukaryotic cells, by catalysing the conjugation of electrophilic substrates to glutathione (GSH) and detoxification both in external and internal cellular enviornments. Previous studies of our team suggested that SjGST had profound on the growth of human breast cancer cells in vitro. In order to analyse the effect of SjGST on the proliferation and migration of human breast cancer cell line, MDA-MB 435s , we initially constructed plasmid containing gst fragment in pAcGFP-N1 and transfected into MDA-MB 435s cells. Assays for proliferation and migration of the transfected cells showed that no difference between transfected and non-transfected cells was found. Analysis of the transfected gene found a frameshift mutation occurred in the plasmid, and thus no expression was detedted. Thus, we carried out assays for proliferation and migration of the cancer cells using recombiation SjGST instead. Results from assays for proliferation and migration showed that SjGST enhance both proliferation and migration of MDA-MB 435s. Furthermore, the recombinant protein was a strong inhibitor to cell death, probably by detoxification pathway. But the mechanism of action of detoxification of shikonin by the recombinant protein, however remains unknow.
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The role of substrate mechanics in nanotoxicity mediated by endocytosisBoehm, Robert C. January 2017 (has links)
No description available.
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Avaliação da atividade biológica de um terpeno em linhagem de câncer de pulmão de pequenas células (A549)Stoll, Stefani Natali 11 December 2017 (has links)
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Previous issue date: 2018-06-20 / CAPES / O câncer se trata de uma das principais causas de mortes no mundo, sendo o câncer de pulmão o primeiro em incidência mundial. No Brasil, o câncer de pulmão é o segundo principal responsável por mortes por câncer em homens (após câncer de próstata) e o quarto em mulheres - sendo o Rio Grande do Sul o segundo estado brasileiro com maior incidência de casos de câncer. Caracterizado pelo crescimento desordenado e desenfreado de células, o desenvolvimento tumoral é definido pela evasão da morte celular e tem sido intimamente correlacionado à inflamação. Tratamentos usuais do câncer, como quimioterapia e radioterapia, apresentam elevados efeitos adversos ao paciente, além do alto custo. Tendo em vista que a maior parte das drogas antineoplásicas produzidas são oriundas de compostos naturais ou de seus derivados, é constante a busca por novos metabólitos de origem natural, em especial os de origem vegetal - que apresentam potencial na busca por novas moléculas para síntese de fármacos. Diversos fitocomponentes, como o terpeno α-terpineol (TPN), apresentam efeito antiproliferativo e anticancerígeno em linhagens de adenocarcinoma de mama, próstata e ovário, e leucêmicas. Neste trabalho foi avaliado o potencial anti-proliferativo do TPN frente à seis linhagens tumorais humanas (A549, MCF-7, HT-29, Caco-2, LNCaP, ACP-03), sendo a A549 (câncer de pulmão) selecionada para experimentos de tratamento repetido por seis dias em associação com o quimioterápico doxorrubicina (DOXO). O mecanismo de morte celular, marcadores moleculares, atividade
enzimática (JAK-3, JNK-3, p38-α), migração celular e inibição de TNF-α foram avaliados. Dentre as seis linhagens analisadas, três (A549, MCF-7, HT-29) apresentaram redução significativa da viabilidade celular após tratamento com o TPN por 48 h. A associação do TPN com a DOXO na linhagem A549 potencializou o efeito anti-proliferativo em comparação com a DOXO. Após seis dias de tratamento observou-se comportamento dose- e tempo-dependente da DOXO e do TPN sem apresentar diferença estatística entre eles. O TPN apresentou atividade inibitória da p38-α (IC50=729 μ M) e JAK3 (IC50=6,3 μM). Após 48 h de
tratamento, observou-se e necrose nas células tratadas com DOXO (21,5 %) e TPN (7,3 %).Com a associação de ambas as drogas, a taxa de necrose elevou-se para 33,5 %, bem como para os seis dias de tratamento (52,3 %). Observou-se ainda, redução da migração celular após 120 h de tratamento com o TPN em comparação ao controle. Com base no exposto acima, o TPN apresenta potencial como biomolécula para o desenvolvimento de novos fármacos ou mesmo seu uso, como coadjuvante no tratamento de câncer de pulmão humano. / Cancer is one of the leading causes of death worldwide, with lung cancer as the major one. In Brazil, lung cancer is the second leading cause of cancer deaths in men (after the prostate cancer) and fourth in women. Rio Grande do Sul is the second Brazilian state with the highest incidence of cancer. Characterized by disordered cell growth, tumor development is defined by cell death evasion and has been closely correlated to inflammation. Standard cancer treatments, such as chemotherapy and radiotherapy, cause adverse effects on patients. Considering that most of the antineoplastic drugs produced are derived from natural compounds or their derivatives, natural products (especially those of plant origin) present potential in the search for new molecules for drug synthesis. Several phytoconstituents, such as the terpene α-terpineol (TPN), have antiproliferative and anticancer effects in cell lines of breast, prostate and ovary carcinomas, and leukemic cells. In the present study, the anti-proliferative potential of TPN on six human tumor cell lines (A549, MCF-7, HT-29, Caco-2, LNCaP and ACP-03) was evaluated. The A549 cell line (lung adenocarcinoma) was selected
for experiments of six days with TPN and doxorubicin (DOXO) co-treatment. Mechanisms of cell death, molecular markers, enzymatic activity (JAK-3, JNK-3, p38-α), cell migration and inhibition of TNF-α were evaluated. Among the six lines, three of them (A549, MCF-7, HT-29) have shown a significant reduction of cell viability after 48 h treatment with TPN. Co-treatment of TPN and DOXO on A549 potentiated the antiproliferative effect compared with DOXO treatment. After six days of treatment, dose and time-dependent effect of DOXO and TPN were observed. TPN showed inhibitory activity on p38-α (IC50 = 729 μM) and JAK3
(IC50 = 6.3 μM). After 48 h of treatment, necrosis was observed in cells treated with DOXO (21,5 %) and TPN (7,3 %). The co-treatment of both drugs increased the necrosis rate up to 33,5 %, as well in the 6th day of treatment (52,3 %). It was also observed a cell migration reduction after 120 h of TPN treatment in comparison with control. Based on that, TPN can be characterized as a potential biomolecule for new drugs development or even its use as adjuvant in the treatment of lung adenocarcinoma.
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The Effect of Polydimethylsiloxane Substrate Modification on A549 Human Epithelial Lung Cancer Cell Morphology and BiomechanicsWard, Sherissa A. 01 May 2015 (has links)
In this thesis the effect of mechanical stimuli on A549 lung cancer cells is studied. Modifications of polydimethylsiloxane (PDMS) surfaces are employed to alter the mechanical stimuli applied to the cells. Flat substrates are first studied and then micropillared substrates are designed, fabricated, and tested as a method to alter the mechanical properties of the PDMS surfaces.
Molds with micro-pillars are designed then fabricated from silicon using deep reactive ion etching. From these molds, a negative then a positive replicate is made using PDMS. The pillared PDMS substrates are fabricated in 10 geometries and used for experiments. A549 cells are cultured on these surfaces then analyzed using fluorescence microscopy and atomic force microscopy (AFM). Fluorescence microscopy images processed by ImageJ software measure the cell spreading area (m2) while AFM quantifies the cell stiffness (kPa).
For flat substrates, the cell stiffness and spreading area increase with increasing substrate stiffness. Further, results on pillared substrates show a similar trend based on pillar geometry changes. For pillared substrates, the A549 cell stiffness and spreading area increase as the height decreases, yet there is decreased cell stiffness and spreading area as the diameter and spacing decreases. The experiments show that changes in surface properties and only mechanical stimuli alter cellular morphology and biomechanics
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Safrole Oxide Induces Apoptosis by Activating Caspase-3, -8, and -9 in a549 Human Lung Cancer CellsDu, Ai, Zhao, Bao Xiang, Yin, De Ling, Zhang, Shang Li, Miao, Jun Ying 01 January 2006 (has links)
Previously we found that 3,4-(methylenedioxy)-1-(2′,3′- epoxypropyl)-benzene (safrole oxide) induced a typical apoptosis in A549 human lung cancer cells. In this study, we further investigated which caspases were activated by safrole oxide during the apoptosis. The data showed that the activity of caspase-3, -8, and -9 was significantly enhanced by the compound, which suggested that safrole oxide might be used as a caspase promoter to initiate lung cancer cell apoptosis.
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Lipoplexes recouverts d’acide hyaluronique pour le ciblage d’ARN interférant à des cellules tumorales surexprimant le récepteur CD44 / Hyaluronic acid-coated lipoplexes for siRNA targeting to tumor cells overexpressing CD44 receptorsLeite Nascimento, Thais 17 September 2015 (has links)
Des progrès récents dans l’utilisation préclinique et clinique des petits ARN interférents (siRNA) ont montré leur potentiel en tant qu’inhibiteur de la synthèse protéique dans de nombreuses pathologies comme le cancer. L’administration des siRNA rencontre un certain nombre de problèmes liés à leur dégradation rapide dans les milieux biologiques, ainsi qu’à leur difficulté à pénétrer au sein des cellules cibles en raison de leur hydrophilie et de leur charge négative. Une des clés de l’amélioration de l’efficacité thérapeutique de ces molécules repose sur l’emploi de vecteurs. Au cours de cette thèse, des lipoplexes capables de protéger les siRNA contre la dégradation et de favoriser leur transport jusqu’aux cellules cibles ont été développés et optimisés. Pour ce faire, des lipoplexes recouverts d’HA ont été formulés pour la vectorisation active de siRNA vers des cellules tumorales surexprimant le récepteur CD44. Dans la première partie de cette thèse, la formation des lipoplexes a été étudiée, ainsi que les paramètres influençant leur organisation supramoléculaire. L'insertion de l'HA dans la structure du liposome au moment de la formation des vésicules a entraîné une augmentation de la taille des liposomes en fonction de la concentration d’HA. Leur complexation avec les siRNA a encore augmenté la taille des particules obtenues. L’ajout des acides nucléiques lors de la formation des lipoplexes a provoqué un déplacement d'une partie du conjugué HA-DOPE de la structure des lipoplexes, comme montré par électrophorèse capillaire. La titration calorimétrique isotherme et les études de diffraction des rayons X ont démontré que, sous l’effet des interactions électrostatiques avec les siRNA, un réarrangement des bicouches lipidiques a lieu, conduisant à la formation de vésicules oligolamellaires, confirmé visuellement par cryo-microscopie. Enfin, le positionnement convenable de l’HA sur la surface des lipoplexes et sa capacité de se lier spécifiquement aux récepteurs de CD44 ont été démontrés par la technique de résonance plasmonique de surface. Dans la deuxième partie de cette thèse, la capture cellulaire et localisation intracellulaire des lipoplexes-HA ont été évalués par cytométrie en flux et microscopie de fluorescence, et ont montré que les lipoplexes modifies par l’HA sont internalisés plus rapidement que les lipoplexes non modifiés, et une fois dans des cellules, ils sont localisés principalement à l’intérieur des endosomes. La capacité des lipoplexes à transporter des molécules de siRNA intactes au cytoplasme a été confirmée par 81 % d'inhibition d'expression de luciferase in vitro sur la lignée cellulaire de cancer du poumon A549-luc. In vivo, le traitement avec les lipoplexes-HA transportant un siRNA anti-luciferase a mené à une diminution statistiquement significative de l’expression de luciferase, ce qui a été confirmé par la réduction de l'expression d’ARNm de la luciferase dans le poumon des animaux traités avec les lipoplexes-HA. L'analyse de la distribution des lipoplexes dans les poumons a montré que les lipoplexes modifiés par l’HA sont distribués de façon plus importante et plus homogène dans le tissu pulmonaire que les lipoplexes non modifiés. Dans la troisième partie de cette thèse, la diffusion des lipoplexes-HA de siRNA dans le mucus a été étudié, afin d’évaluer la faisabilité de l’administration pulmonaire de ces particules. Les études utilisant la technique de « multiple particle tracking (MPT) » ont montré que la présence d’HA combinée à l'ajout de siRNA ont permis l’obtention de deux formulations de lipoplexes présentant une pénétration efficace dans le mucus, les lipoplexes-HA and les lipoplexes-PEG/HA. En conclusion, un système efficace de lipoplexes utilisant siRNA pour l'inhibition de l'expression génique ciblant les récepteurs CD44 a été développé. Les résultats obtenus confirment que les HA-lipoplexes sont capables de libérer efficacement le siRNA dans le cytoplasme des cellules in vitro et in vivo. / Recent progresses in the preclinical and clinical use of small interfering RNA (siRNA) have shown their potential as an inhibitor of protein synthesis in many diseases such as cancer. The administration of siRNA encounters a number of problems related to their rapid degradation in biological media, and their difficulty in penetrating targeted cells due to their hydrophilicity and negative charge. A key to improving the therapeutic efficacy of these molecules is based on the use of vectors. In this thesis, lipoplexes that can protect siRNA against degradation and facilitate their transport into target cells were developed and optimized. To do this, lipoplexes covered with HA were formulated for active vectorization of siRNA to tumor cells overexpressing the receptor CD44.In the first part of this thesis, the formation of lipoplexes was studied, and the parameters influencing their supramolecular organization. Insertion of HA within the liposome structure during vesicle formation resulted in the increase in liposome size as a function of HA concentration. Their complexation with siRNA has further increased the size of the particles obtained. The addition of siRNAs when forming lipoplexes caused a displacement of a portion of the HA-DOPE conjugate from the lipoplexes structure, as shown by capillary electrophoresis. The isothermal titration calorimetry and X-ray diffraction studies showed that a rearrangement of the lipid bilayers occur under the effect of electrostatic interactions with siRNAs, leading to the formation of oligolamellar vesicles, which was visually confirmed by cryo-microscopy. Finally, the proper positioning of the HA on the surface of the lipoplexes and its ability to specifically bind to the CD44 receptors has been demonstrated by the surface plasmon resonance technique.In the second part of this thesis, cellular uptake and intracellular localization of HA-lipoplexes were assessed by flow cytometry and fluorescence microscopy, and showed that lipoplexes modified by HA are internalized more rapidly than unmodified lipoplexes, and once in the cells, they are mainly localized within the endosomes. The ability of lipoplexes to transport intact siRNA molecules to the cytoplasm was confirmed by 81% of luciferase in vitro expression inhibition on the lung cancer cell line A549-luc. In vivo, treatment with HA-lipoplexes carrying anti-luciferase siRNA led to a statistically significant decrease in expression of luciferase, which was confirmed by reducing the mRNA expression of luciferase in lungs of animals treated with HA-lipoplexes. The analysis of the distribution of lipoplexes in the lungs showed that lipoplexes modified with HA are distributed more evenly in the lung tissue than unmodified lipoplexes.In the third part of this thesis, the movement of siRNA HA-lipoplexes in the mucus was studied to assess the feasibility of administering these particles directly to the lungs. Studies using the technique of "multiple particle tracking (MPT)" showed that the presence of HA combined with the addition of siRNA allowed the preparation of two lipoplexes formulations with efficient mucus-penetration, HA-lipoplexes and PEG/HA-lipoplexes.In conclusion, an efficient siRNA lipoplex system for inhibiting gene expression targeted TO the CD44 receptorS has been developed. The results confirm that the HA-lipoplexes are able to effectively release in vitro and in vivo the siRNA molecules in the cytoplasm of cells.
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Le surfactant pulmonaire, une barrière déterminante de la réponse des cellules à l'exposition aux nanoparticules / Pulmonary surfactant, a critical factor in the cell response to nanoparticles exposureMousseau, Fanny 26 January 2017 (has links)
Les particules fines émises par l'activité humaine sont la cause de diverses pathologies pulmonaires et cardiaques. Les particules de taille inférieure à 100 nm, appelées nanoparticules, sont particulièrement nocives car une fois inhalées, elles peuvent atteindre les alvéoles pulmonaires, lieux des échanges gazeux. Dans les alvéoles, les nanoparticules entrent d'abord en contact avec le surfactant pulmonaire. Ce fluide biologique tapisse les cellules épithéliales des alvéoles sur une épaisseur de quelques centaines de nanomètres et est composé de phospholipides et de protéines, les phospholipides étant assemblés sous forme de vésicules et corps multi-lamellaires. Dans ce travail, nous avons sélectionné des nanoparticules modèles de nature différente connues pour leur toxicité cellulaire (latex, oxydes métalliques, silice). Leur interaction avec un fluide pulmonaire mimétique administré aux prématurés (Curosurf®) a été étudiée en détail par microscopie optique et électronique, et par diffusion de la lumière. Nous avons mis en évidence que cette interaction est non spécifique et d'origine électrostatique. La diversité des structures hybrides obtenues entre particules et vésicules témoigne cependant de la complexité de cette interaction. En contrôlant cette interaction, nous avons formulé des particules couvertes d’une bicouche supportée de Curosurf® qui possèdent des propriétés remarquables de stabilité et de furtivité en milieu biologique.Dans une seconde partie, nous avons étudié le rôle du surfactant pulmonaire sur l’interaction entre particules et cellules épithéliales alvéolaires (A459). A l'aide d'expériences de biologie cellulaire réalisées in vitro, nous avons observé que la présence de surfactant diminue de manière significative le nombre de particules internalisées par les cellules. Dans le même temps, nous avons constaté une augmentation importante de la viabilité cellulaire. Une conclusion majeure de notre travail concerne la mise en évidence du rôle protecteur joué par le surfactant pulmonaire dans les mécanismes d'interaction des nanoparticules avec l'épithélium alvéolaire / Particulate matter emitted by human activity are the cause of various pulmonary and cardiac diseases. After inhalation, nanoparticles (ie particles smaller than 100 nm) can reach the pulmonary alveoli, where the gas exchanges take place. In the alveoli, the nanoparticles first encounter the pulmonary surfactant which is the fluid that lines the epithelial cells. Of a few hundreds of nanometers in thickness, the pulmonary fluid is composed of phospholipids and proteins, the phospholipids being assembled in multilamellar vesicles. In this work, we considered model nanoparticles of different nature (latex, metal oxides, silica). Their interaction with a mimetic pulmonary fluid administered to premature infants (Curosurf®) was studied by light scattering and by optical and electron microscopy. We have shown that the interaction is non-specific and mainly of electrostatic origin. The wide variety of hybrid structures found in this work attests however of the complexity of the phospholipid/particle interaction. In addition, we succeeded in formulating particles covered with a Curosurf® supported bilayer. These particles exhibit remarkable stability and stealthiness in biological environment. In a second part, we studied the role of the pulmonary surfactant on the interactions between nanoparticles and alveolar epithelial cells (A459). With cellular biology assays, we observed that the number of internalized particles decreases dramatically in presence of surfactant. At the same time, we found a significant increase in the A459 cell viability. Our study shows the importance of the pulmonary surfactant in protecting the alveolar epithelium in case of nanoparticle exposure
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Biotechnological potential of lectins: induction of apoptosis in A549 cells, pro-healing effects on experimental wounds and cell toxicity analysis on Artemia sp. / Potencial biotecnolÃgico de lectinas: induÃÃo de apoptose em cÃlulas A549, efeito prÃ-cicatrizante em feridas experimentais e anÃlise de toxicidade sobre Artemia sp.Francisco Vassiliepe Sousa Arruda 29 November 2011 (has links)
FundaÃÃo de Amparo à Pesquisa do Estado do Cearà / This work evaluated the biotechnological potential of lectins in the induction of apoptosis of neoplastic cells; the effect on wound healing in a murine model (in vivo) and established the level of toxicity on Artemia sp. Lectins are proteins or glycoproteins ubiquitously distributed in nature, being found from bacteria to humans. Since carbohydrates can act as mediators of biological information, the interaction with lectins can trigger some biologically important effect. To verify the role of lectins in the induction of apoptosis, A549 cells (lung carcinoma) were grown for 1 hour with lectins isolated from seeds of Canavalia ensiformis (ConA), C. brasiliensis (ConBr), C. boliviana (ConBol), C. grandiflora (Cgran) and C. gladiata (CGL) labeled with FITC. In addition, the relative gene expression of p53, Bax, Bcl-2 and caspase 9 was also evaluated when the cells were cultured with ConA, ConBr and ConBol. The data showed that all lectins interacted with A549 cells. Nevertheless, p53 and Bax had no significant change. Unlike, the expression of BCL-2 was down-regulated while caspase 9 was up-regulated by treatment with lectins. Concerning the pro-healing potential, the lectin isolated from the red alga Bryothamnion seafortii (BS) was tested by topical treatment of skin lesions. The data showed that BS improved the quality of healing, probably through the induction of fibroblast proliferation. Finally, the lethality test of Artemia sp. was carried out to determine the toxicity of some Diocleinae lectins. ConBr is the most toxic lectin against Artemia, while ConA is the least toxic, and ConBol, ConM, ConGr and CGL exhibit intermediate levels of toxicity. / Este trabalho avaliou o potencial biotecnolÃgico de lectinas na induÃÃo da apoptose de cÃlulas neoplÃsicas, o efeito sobre a cicatrizaÃÃo de feridas em modelo murino (in vivo) e estabeleceu o nÃvel de toxicidade sobre Artemia sp. Lectinas sÃo proteÃnas ou glicoproteÃnas distribuÃdas ubiquamente na natureza, sendo encontradas desde bactÃrias atà seres humanos. Tais proteÃnas possuem a capacidade de ligar-se seletivamente a carboidratos. Considerando que carboidratos possam atuar como mediadores da informaÃÃo biolÃgica, a sua interaÃÃo com lectinas pode desencadear algum efeito biolÃgico importante. Para verificar o papel das lectinas sobre a induÃÃo da apoptose, cÃlulas A549 (carcinoma de pulmÃo) foram cultivadas durante 1 hora juntamente com lectinas isoladas das sementes de Canavalia ensiformis (ConA), C. brasiliensis (ConBr), C. boliviana (ConBol), C. grandiflora (Cgran) e C. gladiata (CGL) marcadas com FITC. Em adiÃÃo, a expressÃo gÃnica relativa de p53, Bax, BCL-2 e caspase 9 foi tambÃm avaliada quando as cÃlulas foram cultivadas com ConA, ConBr e ConBol. Os dados mostraram que todas as lectinas intergiram com as cÃlulas A549. NÃo obstante, p53 e Bax nÃo tiveram nenhuma alteraÃÃo significativa. PorÃm, BCL-2 teve sua expressÃo diminuÃda enquanto a da caspase 9 foi aumentada pelo tratamento com as lectinas. Com relaÃÃo ao potencial pro-cicatrizante, a lectina isolada da alga vermelha Bryothamnion seafortii (BS) foi testada atravÃs do tratamento tÃpico de lesÃes cutÃneas. Os dados mostraram que BS melhora a qualidade da cicatrizaÃÃo, muito possivelmente atravÃs da induÃÃo da proliferaÃÃo de fibroblastos. Por fim, o teste de letalidade sobre Artemia sp. foi utilizado para verificar a toxicidade de algumas lectinas da subtribo Diocleinae. Os resultados mostraran que ConBr e ConA sÃo as lectinas mais tÃxica e menos tÃxica, respectivamente. ConBol, ConM, Cgran e CGL exibiram nÃveis intermediÃrios de toxicidade.
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Pseudomonas aeruginosa biofilm and planktonic bacteria display different virulence mechanisms when co-cultured with human A549 lung cells using the Calgary Biofilm Device co-culture systemBowler, Laura January 2012 (has links)
Cystic Fibrosis (CF) is the most common hereditary genetic disorder among Caucasians. Pseudomonas aeruginosa is a major cause of morbidity in cystic fibrosis patients. Chronic infection with P. aeruginosa eventually occurs and is associated with a switch to biofilm formation of the bacteria. The symptoms and pathology of acute and chronic P. aeruginosa infections differ greatly. The first line of defense within the lung is the physical barrier of the lung epithelia. The examination of established biofilm interactions with lung epithelia is difficult. Here, I use the Calgary Biofilm Device co-culture system to conduct the concurrent analysis of established biofilms and planktonic bacteria with A549 lung cells.
Comparison of P. aeruginosa biofilm and planktonic bacteria’s effects on A549 lung cells showed that planktonic bacteria caused more A549 cell rounding and death, while biofilm stimulated more IL-8 release by epithelial cells. Biofilm was shown to secrete significantly more Pseudomonal Elastase than planktonic, causing A549 morphological changes and loss of tight junctions. The antimicrobial peptide LL-37 was shown to differentially affect biofilm and planktonic bacteria. LL-37 caused a decrease in twitching of planktonic bacteria and exposure to LL-37 for 48 hours resulted in a decrease in elastase secretion likely due to down-regulated type 2 secretion. When established biofilms were compared with newly adherent biofilms, young biofilms were shown to have characteristics similar to both planktonic bacteria and mature biofilms. From this data we can follow the pattern of bacterial virulence as P. aeruginosa transitions from the planktonic mode of growth to the eventual mature biofilm that is associated with chronic infection.
In conclusion, this study provides the foundation for a co-culture system that can be used to study the host-pathogen interactions of mammalian epithelia with established P. aeruginosa biofilms. The future adaptations of this model will better represent the in vivo characteristics of chronic lung infection to delineate ongoing virulence mechanisms of the bacteria causing host cell stimulation and damage. / May 2016
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