Inflammation plays an important role in responding to injury and combating infections. In this thesis, I examine how inflammation is regulated by cytokines responsible for driving initial immune responses to combat infections. Toll-Like receptor (TLR)-mediated activation of monocytes, macrophages and dendritic cells can lead to the co-expression of proinflammatory cytokines including IL-1β, IL-23, and IL-27. IL-23 and IL-27 belong to the IL-12 cytokine family yet have distinct functions; IL-23, along with IL-1β, regulates TH17 cell differentiation, while IL-27 supports TH1 proliferation and inhibits TH17 differentiation. Our lab has previously demonstrated that IL-27 can modulate inflammasome activation, the multi-protein regulatory complex that produces bioactive IL-1β; however, the mechanism behind this is poorly understood. Similarly, the effect of IL-27 on IL-23 expression has not been well described. Using the CD14+ THP-1 monocytic cell line as a model system, I investigated the role of IL-27 on LPS-mediated inflammasome activation and IL-23 expression. To induce inflammasome activation, CD14+ THP-1 cells were treated with LPS and/or IL-27, followed by treatment with ATP. I demonstrated that IL-27-enhanced inflammasome activation, which is associated with increased surface expression of LPS and ATP receptors: TLR4 and P2X7 respectively. Furthermore, costimulation resulted in increased secretion of ATP from CD14+ THP-1 cells. Inhibition of ATP signaling and inflammasome activation significantly decreased secreted IL-1β, suggesting that an ATP autocrine feedback loop is driving IL-1β secretion. Moreover, LPS and IL-27 costimulation increased IL-23 expression concurrent with that of IL-1β and ATP secretion. Furthermore I showed that IL-23 secretion is dependent on inflammasome activation and IL-1β, and ATP signaling following IL-27 and LPS priming. My data point to a novel mechanism of IL-27 enhanced LPS-induced IL-1β and IL-23 secretion from CD14+ THP-1 cells through an ATP autocrine feedback loop. / Thesis (Master, Microbiology & Immunology) -- Queen's University, 2014-06-26 15:18:20.124

Thesis (Ph.D.)--University of Melbourne, Dept. of Medical Biology, 2006. / Typescript. Includes bibliographical references (leaves 189-208).

Thèses (Ph.D.)--Université de Sherbrooke (Canada), 1998. / Titre de l'écran-titre (visionné le 20 juin 2006). Publié aussi en version papier.

Thesis (M. Sc.)--University of Canterbury, 2006. / Typescript (photocopy). Includes bibliographical references (leaves 71-79). Also available via the World Wide Web.

Thesis (M.S. )--University of Tennessee Health Science Center, 2009. / Title from title page screen (viewed on September 19, 2009). Research advisor: Jegdish Babu Ph.D. Document formatted into pages (x,36 p. : ill.). Vita. Abstract. Includes bibliographical references (p. 32-36).

Thesis (doctoral)--Universiteit van Amsterdam.

Thesis (M.Med.Sc.) - University of Queensland, 2003. / Includes bibliography.

Orientador: Maria Teresinha Serrão Peraçoli / Banca: Maria de Lourder Ribeiro de Souza da Cunha / Banca: Vanessa Lara / Banca: Iracilda Z. Carlos / Banca: Sueli Calvi / Resumo: Receptores Toll-like RECONHECER componentes distintos da FUNGOS para iniciar a resposta imune inata. Examinamos se Paracoccidioides brasiliensis OU SEUS gp43 antígenos imunodominantes pode modular IN VITRO E TLR2 TLR4 expressão e produção TRIGGER citocinas por monócitos humanos. Monócitos de indivíduos saudáveis ​​foram incubadas com gp43 LYPOPOLYSACCHARIDE, (LPS) ou mortas pelo calor FORMAS leveduriforme do P. brasiliensis em uma proporção de 50 monócitos por célula fúngica (Pb18) a 37 º C por 4h e 18h. A EXPRESSÃO DE TLR2 E TLR4 SOBRE SUPERFÍCIE monócitos, e TNF-alfa, IL-10 e IL-12p40 PRODUÇÃO foram determinados por citometria de fluxo e ELISA respectivamente. Os resultados mostraram que a estimulação de monócitos COM OU LPS Pb18 PROMOVIDO UP-regulação da expressão TLR2 E TLR4 SOBRE SUPERFÍCIE EM RELAÇÃO monócitos às células não-estimulados EM AMBAS AS 4H e 18h de cultura, e aumentaram os níveis de TNF-alfa, IL- 10 e IL-12p40 PRINCIPALMENTE EM 18H DA CULTURA. POR OUTRO LADO, E EXPRESSÃO TLR4 BAIXA ALTA TLR2 são evocados por gp43 AT 4H DA CULTURA, associadas a altos níveis de TNF-alfa. No entanto, após 18H UMA MUDANÇA DE ALTA E BAIXA TLR2 TLR4 EXPRESSÕES foi seguido por elevados níveis de IL-10 e IL-12p40. Estes resultados sugerem que a gp43 pode induzir um desequilíbrio entre RESPOSTAS pró e anti-inflamatório em FUNGOS-monócitos interações, um efeito modulatório na CAMINHO TLR. AS TNF-alfa pode estar envolvida na patogênese da paracoccidioidomicose, O EFEITO regulatórios induzidos por gp43, VIA upregulation de TLR2 EXPRESSÃO E IL-10 produção, pode ser importante para proteger contra a lesão de tecido que é descrito neste micose. / Abstract: Toll-like receptors recognize distinct components of fungi to initiate the innate immune íesponse. We examined whether Paracoccidioides brasiliensis ar its immunodominant antigen gp43 can modulate in vitro TLR2 and TLR4 expression and trigger cytokine production by human monocytes. Monocytes from healthy individuaIs were incubated with gp43, IypopoIysaccharide (LPS) or heat-killed yeast forms of P. brasiliensis in a ratio of 50 monocytes per funga! cell (pb 18) at 37°C for 4h and I8h. The expression of TLR2 and TLR4 on monocyte surface, and TNF-alpha, IL-Io and IL-I2p4o production were determined by flow cytometry and ELISA respectiveIy. The results showed that monocyte stimuIation with LPS ar Pb18 promoted up-reguIation ofthe TLR2 and TLR4 expression on monocyte surface in reIation to the non-stimuIated cells at both 4h and I8h ofculture, and induced higher IeveIs ofTNF-aIpha, IL-Io and IL-12p4o mainly at I8h of culture. On the other hand, high TLR4 and low TLR2 expression were elicited by gp43 at 4h of cuIture, associated with higher Ievels of TNF-aIpha. However, after 18h a change to high TLR2 and !ow TLR4 expressions was followed by e1evated levels of IL-Io and IL-12p4o. These results suggest that gp43 might induce an imbalance between pro- and anti-inflammatory responses in fungal-monocyte interactions by a modulatory effect on TLR pathway. As TNF-alpha may be invoIved in the pathogenesis of paracoccidioidomycosis, the regulatory effect induced by gp43, via upregulation of TLR2 expression and IL-Io production, can be important to protect against tissue injury which is described in this mycosis. / Doutor

Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2016-09-01T11:58:23Z No. of bitstreams: 2 Dissertação - Poliana Ribeiro Valadares Veras - 2015.pdf: 4546054 bytes, checksum: d4bed497af887b82ba08b0d21d58ed42 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2016-09-01T11:58:38Z (GMT) No. of bitstreams: 2 Dissertação - Poliana Ribeiro Valadares Veras - 2015.pdf: 4546054 bytes, checksum: d4bed497af887b82ba08b0d21d58ed42 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2016-09-01T11:58:38Z (GMT). No. of bitstreams: 2 Dissertação - Poliana Ribeiro Valadares Veras - 2015.pdf: 4546054 bytes, checksum: d4bed497af887b82ba08b0d21d58ed42 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2015-07-02 / American tegumentary leishmaniasis (ATL) is an infectious parasitic disease caused by Leishmania protozoa. The disease presents as cutaneous leishmaniasis (CL) and mucosal leishmaniasis (ML). The mechanisms of the immunopathogenesis and infection control are not yet fully understood, and monocytes can be involved in these mechanisms. The monocytes are divided into three subsets (CD14hiCD16-, classical monocytes; CD14hiCD16+, the intermediates; and CD14loCD16+ non- classical) and are the major cell producing cytokines in peripheral blood.The objective of this study was to assess possible alterations in the percentages of monocytes subsets; and in the tumor necrosis factor (TNF) and interleukin 10 (IL -10) production in whole blood cultures from patients with CL and ML, before and after treatment. Peripheral blood from patients (n = 54; 31 CL and ML 23) and controls (n = 54) was used to identify monocytes by flow cytometry and for whole blood cultures. The blood was incubated in the absence (medium) or presence of toll-like receptor agonists (Pam3Cys and LPS for TLR2 and TLR4, respectively) or L. (V.) braziliensisantigens (AG) to assess TNF and IL-10. Cytokines were quantified by enzyme-linked immunosorbent assay (ELISA).The results showed an increase in the percentage of CD16+ monocytes, especially CD14loCD16+monocyte subset in CL patients, but not in ML, before treatment (p <0.05). After treatment, the percentages of these monocytes in CL patients back to similar levels of those from healthy individuals. In patients with ML, there was also a reduction in the percentages of CD16+ monocytes after treatment. The production of TNF and IL-10 was not significantly altered in whole blood cultures from patients, compared with those from healthy controls. Among the stimuli used, only the AG did not induce significant amounts of IL-10 in whole blood cultures from patients. After treatment, TNF concentrations decreased in CL whole blood cultures, except when the stimulus was Pam3Cys (TLR2), which induced an increase in TNF levels (p <0.05). In ML whole blood cultures no significant differences were detected between the concentrations of TNF and IL-10 produced before and after treatment.The IL-10 concentrations were not significantly altered after treatment of CL patients. The data indicate that percentages of CD16+ monocytes are increased in CL. Also, they suggest that monocytes from patients with CL or ML show a decreased capacity to produce IL-10 in response to AG, what can hamper the control of the inflammatory response. The data also suggest that the ability of monocytes to be activatedthrough TLR2 can be suppressed in CL what isrecovered after treatment. An analysis of TLR2 and TLR4 in monocytes from patients with ATL can improve the knowledge about cytokine induction in these cells. / A leishmaniose tegumentar americana (LTA) é uma doença infecto-parasitária causada por protozoários do gênero Leishmania. Esta doença apresenta-se como leishmaniose cutânea (LC) e leishmaniose mucosa (LM). Os mecanismos da imunopatogenia e do controle da infecção ainda não estão completamente esclarecidos, sendo que os monócitos podem participar destes mecanismos. Os monócitos são subdivididos em três populações (CD14hiCD16-, os clássicos; CD14hiCD16+, os intermediários; e CD14loCD16+, os não clássicos) e são as principais células produtoras de citocinas no sangue periférico. O objetivo deste estudo foi avaliar se existem alterações nas proporções das três subpopulações dos monócitos e das citocinas fator de necrose tumoral (TNF) e interleucina 10 (IL-10), em pacientes com LC ou LM, antes e após o tratamento. Sangue periférico de pacientes (n = 54; 31 LC e 23 LM) e controles (n = 54) foi utilizado para identificar os monócitos por citometria de fluxo e para hemoculturas. As hemoculturas foram incubadas na ausência (Meio) ou presença de agonistas (LPS, Pam3Cys) de receptores similares a toll dos tipos dois e quatro (TLR2 e TLR4) ou de antígenos (AG) de L. (Viannia) braziliensis, para avaliar a produção de TNF e IL-10. As citocinas foram quantificadas por ensaio imunoenzimático (ELISA). Os resultados mostraram um aumento da porcentagem dos monócitos CD16+, especialmente da subpopulação CD14loCD16+, em pacientes com LC, mas não com LM, antes do tratamento (p < 0,05). Após o tratamento, as porcentagens destes monócitos, em pacientes com LC, retornaram para níveis similares àqueles de indivíduos sadios. Em pacientes com LM, também ocorreu uma redução das porcentagens dos monócitos CD16+ após o tratamento. A produção de TNF e a de IL-10 não estavam significantemente alteradas nas hemoculturas de pacientes, quando comparadas com as de controles sadios. Entre os estímulos usados, somente o AG não induziu quantidades significantes de IL-10 nas hemoculturas dos pacientes. Após o tratamento, as concentrações de TNF diminuíram nas hemoculturas de pacientes com LC, exceto quando o estímulo foi Pam3Cys (TLR2), o qual induziu aumento na produção de TNF (p < 0,05). Em hemoculturas de pacientes com LM não foram detectadas diferenças significantes entre as concentrações de TNF e IL-10 produzidas antes e após o tratamento. As concentrações de IL-10 também não foram significantemente alteradas após o tratamento dos pacientes com LC. Os dados indicam que as porcentagens de monócitos CD16+ estão aumentadas na LC. Ainda, sugerem que monócitos de pacientes com LC ou LM apresentam uma diminuída capacidade de produção de IL-10 em resposta ao AG, o que pode dificultar o controle da resposta inflamatória. Os dados também sugerem que a capacidade de resposta dos monócitos via TLR2 pode estar suprimida na LC, sendo elevada após o tratamento. Uma análise de TLR2 e TLR4 em monócitos de pacientes com LTA pode auxiliar a entender melhor a indução de citocinas nestas células.

Background: COPD is associated with an increased lung macrophage burden. Whilst lung macrophages may self-renew, recruitment of peripheral blood monocytes from the systemic circulation is considered to represent their principal means of replenishment. Through modulating expression of monocytic chemokines CCL2/CCL3 and their respective receptors (CCR2/CCR1+CCR5), IL-6 could play a key role in facilitating the recruitment of monocytes to the lungs of COPD patients. COPD is associated with enhanced pulmonary and systemic IL-6 levels; concentrations of the soluble IL-6 receptor sIL-6R may be an important determinant of IL-6 signalling in COPD. Trans-signalling through sIL-6R, IL-6 may facilitate recruitment of monocytes in COPD by influencing chemokine and chemokine receptor expression. Aims: 1) To compare levels of IL-6, sIL-6R, CCL2 and CCL3 in the plasma and sputum of COPD and controls. 2) To examine of the effects of IL-6 stimulation on monocyte chemokine receptor gene expression (CCR1, CCR2 and CCR5). 3) To compare subtypes (CD14++CD16-, CD14+CD16+, CD14-CD16++) and chemokine receptor expression (CCR1, CCR2, CCR5) of monocytes in COPD (paired stable & exacerbating) and controls. 4) To compare the migratory ability of monocytes from COPD and controls. 5) To compare numbers of marginated CX3CR1+ monocytes in the pulmonary microvasculature and proliferation status (Ki67 positivity) of alveolar macrophages in COPD and controls. Methods: 1) MSD soluble marker analysis was performed on plasma and sputum supernatant. 2) Monocytes underwent stimulation with IL-6 and sIL-6R; chemokine receptor expression was determined by quantitative PCR. 3) Flow cytometry was performed on whole blood to determine monocyte subtype and chemokine receptor expression. 4) Monocyte migration towards sputum supernatant was assessed using a transwell system incorporating fluorescence based detection of DNA from migrated cells. 5) Immunofluorescence and immunohistochemistry was performed on lung tissue (obtained from patients undergoing surgical resection of lung carcinoma) to identify marginated (CX3CR1+CD14+, CX3CR1+CD16+) monocytes and proliferating alveolar macrophages (Ki67) respectively. Results and Conclusion: Levels of sIL-6R were increased in the lungs and systemic circulation of COPD patients implying potential for enhanced IL-6 trans-signalling: monocytes cultured in the presence of IL-6+sIL-6R upregulated expression of the CCR5 gene. A greater proportion of circulating COPD CD14++CD16- and CD14+CD16+ monocytes were demonstrated to express CCR5 compared to controls indicating that CCR5 ligands may have an important influence over monocyte migration in COPD. Levels of CCR5 ligand CCL3 were significantly elevated in COPD sputum supernatant; IL-6 levels were positively associated with CCL3 indicating that IL-6 trans-signalling may mediate lung chemokine expression. Nevertheless, COPD monocytes demonstrated impaired migration towards sputum supernatant and reduced margination to pulmonary microvessels. Despite this, the number of alveolar macrophages in COPD was increased; however this was not likely to be related to self-replication owing to low alveolar macrophage Ki67 expression.