As major effector cells of the innate immune response, macrophages must adeptly migrate from blood to infected tissues. Endothelial transmigration is accomplished by matrix metalloproteinase (MMP)-induced degradation of basement membrane and extracellular matrix components. The classical activation of macrophages with LPS and IFN-γ causes enhanced microtubule stabilization and secretion of MMPs. Macrophages upregulate MMP-9 expression and secretion upon immunological challenge, and require its activity for migration during inflammatory response. However, the dynamics of MMP-9 production and intracellular distribution, as well as the mechanisms responsible for its trafficking, are unknown. Using immunofluorescent imaging, we localized intracellular MMP-9 to small Golgi-derived cytoplasmic vesicles that contain calreticulin and PDI, in activated macrophages. Vesicular organelles of MMP-9 aligned along stable subsets of microtubules and colocalized with the anterograde molecular motor protein, kinesin. We demonstrated a functional contribution of stable MTs in the enhanced trafficking of MMP-9 extracellularly, and showed that heterogeneity exists in macrophage cell populations with respect to MMP-9 production.

As major effector cells of the innate immune response, macrophages must adeptly migrate from blood to infected tissues. Endothelial transmigration is accomplished by matrix metalloproteinase (MMP)-induced degradation of basement membrane and extracellular matrix components. The classical activation of macrophages with LPS and IFN-γ causes enhanced microtubule stabilization and secretion of MMPs. Macrophages upregulate MMP-9 expression and secretion upon immunological challenge, and require its activity for migration during inflammatory response. However, the dynamics of MMP-9 production and intracellular distribution, as well as the mechanisms responsible for its trafficking, are unknown. Using immunofluorescent imaging, we localized intracellular MMP-9 to small Golgi-derived cytoplasmic vesicles that contain calreticulin and PDI, in activated macrophages. Vesicular organelles of MMP-9 aligned along stable subsets of microtubules and colocalized with the anterograde molecular motor protein, kinesin. We demonstrated a functional contribution of stable MTs in the enhanced trafficking of MMP-9 extracellularly, and showed that heterogeneity exists in macrophage cell populations with respect to MMP-9 production.

S100A8 is a highly-expressed calcium-binding protein in neutrophils and activated macrophages, and has proposed roles in myeloid cell differentiation and host defense. Functions of S100A8 are not fully understood, partly because of difficulties in generating S100A8 knockout mice. Attempts to silence S100A8 gene expression in activated macrophages and fibroblasts using RNA interference (RNAi) technology were unsuccessful. Despite establishing validated small interfering RNA (siRNA) systems, enzymaticallysynthesized siRNA targeted to S100A8 suppressed mRNA levels by only 40% in fibroblasts activated with FGF-2+heparin, whereas chemically-synthesized siRNAs suppressed S100A8 driven by an S100A8-expression vector by ~75% in fibroblasts. Suppression of the gene in activated macrophages/fibroblasts was low, and some enzymatically-synthesized siRNAs to S100A8, and unrelated siRNA to GAPDH, induced/enhanced S100A8 expression in macrophages. This indicated that S100A8 may be upregulated by type-1 interferon (IFN). IFN-β enhanced expression, but did not directly induce S100A8. Poly (I:C), a synthetic dsRNA, directly induced S100A8 through IL-10 and IFN-dependent pathways. Induction by dsRNA was dependent on RNA-dependent protein kinase (PKR), but not cyclooxygenase-2, suggesting divergent pathways in LPS- and dsRNA-induced responses. New mechanisms of S100A8 gene regulation are presented, that suggest functions in anti-viral defense. S100A8 expression was confirmed in lungs from influenza virus-infected mice and from a patient with severe acute respiratory syndrome (SARS). Multiple pathways via mitochondria mediated S100A8 induction in LPS-activated macrophages; Generation of reactive oxygen species via the mitochondrial electron transport chain and de novo synthesis of ATP may be involved. This pathway also regulated IL-10 production, possibly via PKR. Extracellular ATP and its metabolites enhanced S100A8 induction. Results support involvement of cell stress, such as transfection, in S100A8 expression. A breast tumor cell line (MCF-7) in which the S100A8 gene was silenced, was established using micro RNA technology; S100A8 induction by oncostatin M was reduced by >90% in stably-transfected cells. This did not alter MCF-7 growth. The new approach to investigate the role of S100A8 in a human tumor cell line may assist in exploring its functions and lead to new studies concerning its role in cancer.

Diss. (sammanfattning) Stockholm : Karol. inst., 2003. / Härtill 6 uppsatser.

Thesis (M.Sc.). / Written for the Dept. of Microbiology and Immunology. Title from title page of PDF (viewed 2008/05/14). Includes bibliographical references.

Submitted by Priscila Nascimento (pnascimento@icict.fiocruz.br) on 2013-03-21T18:15:02Z No. of bitstreams: 1 André_C_Ferreira.pdf: 895655 bytes, checksum: fffce754856c9d5194a6fac09f960736 (MD5) / Made available in DSpace on 2013-03-21T18:15:02Z (GMT). No. of bitstreams: 1 André_C_Ferreira.pdf: 895655 bytes, checksum: fffce754856c9d5194a6fac09f960736 (MD5) Previous issue date: 2012 / Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Rio de Janeiro, RJ, Brasil. / A malária é uma doença parasitária causada por protozoários do gênero Plasmodium e representa um grande problema de saúde pública. Sabe-se que metade da população mundial vive em áreas endêmicas, onde esta doença gera cerca de 500 milhões de casos clínicos e em torno de 1 milhão de mortes anualmente. O processo infeccioso da malária é desencadeado por uma resposta imunoinflamatória exacerbada do hospedeiro caracterizada por migração e acúmulo de leucócitos, produção de citocinas pró-inflamatórias e mediadores químicos. Neste processo, as leucointegrinas exercem um papel extremamente importante mediando a adesão, migração e sinalização celular. Neste grupo de integrinas, a CD11d/CD18, que foi descrita mais recentemente está envolvida em diversos eventos patológicos como aterosclerose, dano neuronal e outros. Resultados preliminares de nosso grupo mostraram que animais deficientes (CD11d-/-) para esta integrina apresentam uma maior sobrevida à infecção com Plasmodium berghei Anka (PbA). Entretanto, ainda não se conhece o papel desta integrina na fisiopatologia da malária. O presente trabalho mostrou que a integrina CD11d/CD18 é dinamicamente expressa em macrófagos diferenciados da medula óssea de animais infectados com PbA. Ensaios in vitro com essas células, demonstraram que esta integrina não afeta a capacidade proliferativa dessas células. Além disso, avaliamos parâmetros importantes para a ativação celular, como produção de espécies reativas de oxigênio e citocinas pró- e anti-inflamatórias. Observamos que macrófagos de animais CD11d-/- produzem quantidades significantemente mais baixas de malondialdeído e de TNF- , e níveis altos de IL-10 em relação aos macrófagos de animais CD11d+/+. Além disso, a produção de prostaglandina E2 foi significantemente diminuída em macrófagos provenientes de animais CD11d-/-. Esses dados indicam que a integrina possui um papel importante na modulação da resposta imune. Verificamos ainda que macrófagos de animais CD11d-/- apresentaram uma diminuição na sua capacidade fagocítica de hemácias parasitadas em relação aos macrófagos de animais CD11d+/+. Entretanto, a ausência desta integrina não afetou a capacidade destes macrófagos de fagocitar hemozoína sintética (sHz). Estes resultados juntos sugerem que a integrina CD11d está envolvida no processo de ativação celular dos macrófagos, modulando a resposta imune do hospedeiro na fisiopatologia da malária, o que torna esta molécula um potencial alvo para ações terapêuticas. / Malaria is a parasitic disease caused by protozoa of the genus Plasmodium and is a major public health problem. It is known that half the world population lives in endemic areas where this disease causes about 500 million clinical cases and around 1 million deaths annually. The process of malaria infection is initiated by a host immunoinflammatory response exacerbated characterized by the migration and accumulation of leukocytes, the production of proinflammatory cytokines and chemical mediators. In this process, leukointegrins play a very important role in mediating adhesion, migration and cell signaling. In this group of integrins, CD11d/CD18, which has been described more recently, is involved in gravel pathological events such as atherosclerosis, neuronal damage and others pathologies. Preliminary results from our group have shown that animals deficient (CD11d-/-) for this integrin have a higher survival to infection with Plasmodium berghei Anka (PbA). However, we still do not know the role of CD11d/CD18 integrin in the pathophysiology of malaria. The present study demonstrated that the integrin is dynamically expressed in differentiated bone marrow macrophages from animals infected with PbA. Experiments with these cells in vitro have demonstrated that the integrin does not affect the proliferative capacity of these cells. Furthermore, we evaluated parameters important to cellular activation, such as production of reactive oxygen species, proinflammatory and anti-inflammator cytokines. Observed that macrophages, from deficient mice for the integrin CD11d-/-, produce significantly lower amounts of malondialdehyde and TNF- , and high levels of IL-10 in relation to the macrophages from animals CD11d+/+. Furthermore, the production of prostaglandin E2 was significantly reduced by macrophages from animals CD11d-/-. These data indicate that integrin plays an important role in modulating the immune response. Also verified that macrophages from animals CD11d-/- showed a decrease in their phagocytic ability of infected erythrocytes to macrophages compared to animals CD11d+/+. However, absense of this integrin did not affect the ability of macrophages to phagocytize synthetic hemozoin – sHz. These results together suggest that CD11d integrin is involved in cellular activation of macrophages by modulating the host immune response in the pathophysiology of malaria, which makes this molecule a potential target for therapeutic actions.

Macrophages associés aux tumeurs (TAMs) sont étroitement liés à l'initiation et la croissance tumorale, l'angiogenèse, l'invasion et les métastases tumorale, la résistance au traitement anti-cancéreux et sont associées à un mauvais pronostic dans de nombreux cancers. La radiothérapie est un des traitements les plus importants antitumoraux et a été montré pour pouvoir moduler les fonctions TAMs. Cependant, les mécanismes moléculaires dans l'activation des macrophages induite par irradiation sont largement inconnues. Dans cette étude, nous avons démontré que les rayonnements ionisants (IR) induit une activation des macrophages de type M1 in vitro et in vivo, qui est associée à une inhibition de la croissance tumorale induite par IR. Nous révélons que la protéine X induit par IR est essentiels dans le déclenchement de l'activation des macrophages. Nous confirmons l'importance de ces résultats en montrant que la sur-expression de la protéine X est liée à une augmentation des macrophages de type M1 chez les patients rectales suivants radiothérapie néo-adjuvante. L'accumulation des macrophages de type M1 est associée à une réponse antitumorale améliorée. Ce travail dévoile des rôles importants de la protéine X dans l'activation des macrophages IR-induite et constitue une base pour le développement de nouvelles stratégies thérapeutiques pour améliorer l’efficacité de la radiothérapie par modulation de l'activation des macrophages. / Tumour-associated macrophages (TAMs) are closely related to tumour initiation and growth, angiogenesis, tumour invasion and metastasis, anti-cancer treatment resistance and are associated with poor prognosis in many cancers. Radiotherapy is among the most important anti-tumour therapies and has been shown to modulate TAMs functions. However, molecular mechanisms underlying irradiation-induced macrophage activation are largely unknown. In this study, we demonstrated that ionizing radiation (IR) induces macrophage M1 activation both in vitro and in vivo, which is associated with IR-induced tumour growth inhibition. We reveal that IR-induced X protein is critical in triggering macrophage activation. We confirm the significance of these findings by showing that up-regulation of X protein is related with increased M1 macrophages infiltration in rectal patients following neo-adjuvant radiotherapy. Accumulation of M1 macrophages is associated with an improved anti-tumour response. This work unveils important roles of X protein in IR-induced macrophages activation and provides basis for the development of new therapeutic strategies to enhance radiotherapy efficacy through modulating macrophage activation.

It is submitted in this thesis that the degree of activation or inhibition of macrophage function may differ in N. asteroides and N. brasiliensis infections with respect to release of plasminogen activator and of lysozyme The pattern of secretion of plasminogen activator and lysozyme in N. asteroides infections appears to differ in N. brasiliensis infection; and there is possibly a difference in the amount of lysozyme released by 2 day N. asteroides-activated macrophages and 2 day N. brasiliensis -activated macrophages. Strains of Nocardia organism did not influence macrophage morphology or ultrastructure. The study also shows the biochemical characteristics of plasminogen activator and lysozyme release, but not macrophage morphology and ultrastructure, are modified in the first 21 days of experimental Nocardia infections. There are three apparent mechanisms by which virulent strains of N. asteroides manage to survive within macrophages: (i) an ability to inhibit phagosome-lysozome fusion: (ii) alteration in the intraphagosomal pH: and (iii) alteration in the activity of the lysozomal enzyme acid-phosphatase. This study attempted to elucidate further the mechanisms enabling Nocardia organisms to persist and grow within macrophages. Reduced lysozyme release reflects diminished functional status of the macrophages of mice inoculated with N. asteroides or N. brasiliensis at certain times during infection. Reduced intracellular lysozyme levels have been linked with defects in bactericidal function. Such a reduction in intracellular and consequently extracellular levels of lysozyme might explain the capacity of Nocardia to survive intracellularly and to proliferate in the macrophage host.

Thesis advisor: Tricia H. Burdo / Human immunodeficiency virus-associated peripheral neuropathy (HIVPN) continues to be a prevalent comorbidity of HIV infection, despite virologic control due to effective antiretroviral therapy (ART). Symptoms include bilateral tingling, numbness, and pain in distal extremities. Severity of symptoms is associated with a loss of intraepidermal nerve fiber density (IENFD) in the feet. Damage to the dorsal root ganglia (DRG) has also been observed in postmortem tissue analysis from patients with HIV-PN. Treatment options are limited due to a lack of understanding of the disease pathogenesis. Chronic monocyte activation and accumulation of macrophages in peripheral nervous system (PNS) tissues has been reported but few studies have directly demonstrated the role of monocyte/macrophage activation and traffic in the pathogenesis of HIV-PN. The central hypothesis of this thesis is that monocyte activation and traffic mediates PNS neuronal damage. We addressed this hypothesis in several ways. In chapter 2, we describe pathology seen in a rapid disease progression animal model of HIV-PN. We found that an early loss of IENFD preceded a loss of small diameter DRG neurons. In chapter 3, we associated DRG pathology with an accumulation of inflammatory macrophages surrounding DRG neurons. Increased monocyte traffic to the DRG was associated with severity of DRG pathology and with a loss of IENFD. In chapter 4, we directly tested the impact of monocyte traffic on DRG pathology by blocking leukocyte traffic with an anti-VLA-4 antibody, natalizumab. Blocking cell traffic reduced accumulation of macrophages in the DRG and improved pathology. Next we treated animals with methylglyoxal-bisguanylhydrazone (MGBG) to specifically target myeloid cells and reduce their activation. MGBG treatment improved DRG pathology and reduced accumulation of macrophages in tissues. Having demonstrated the role of monocyte traffic and activation, we aimed to identify signaling proteins and inflammatory proteins associated with PNS pathology. We found elevated monocyte chemoattractants in DRG tissue and elevated markers of monocyte activation in plasma that were associated with a loss of IENFD. Together, these studies demonstrate that systemic monocyte activation, macrophage accumulation in DRG tissue, and monocyte traffic plays a major role in SIV-PN pathogenesis. These studies provide novel insight into immune mechanisms that impact neuronal loss during SIV infection. Thus, modulating macrophage activation and reducing monocyte traffic may have therapeutic benefits to patients suffering from or at risk of developing HIV-PN. / Thesis (PhD) — Boston College, 2016. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Biology.

Obesity over the last several has become a major health concern in our country as well as the world. Obesity is also one of the risk factors which lead to several inflammatory complications such as diabetes, artherosclerosis, etc. Two leading factors involved in the causes of inflammatory complications include leptin and low dose endotoxin lipopolysaccharide (LPS). However, the mechanism underlying the involvement of these two mediators is not clearly understood. The purpose of this study is to understand the mechanism underlying inflammatory complications caused by leptin and low dose endotoxin most recently coined metabolic endotoxemia. Interleukin-Receptor Associated Kinase 1 (IRAK-1) is an intracellular signaling component shown to activate NFκB which leads to the induction of proinflammatory mediators. Deletion of IRAK-1 in mice has beneficial effects in alleviating inflammatory complications and human variations in IRAK-1 gene are correlated with higher risks for inflammatory diseases. Therefore, we hypothesized that IRAK-1 is critically involved for the induction of proinflammatory mediators induced by leptin and low dose LPS. IL-6 mRNA levels were measured in THP-1 (human monocytic cells) and wild type and IRAK-deficient bone marrow derived macrophages (BMDM) challenged with different combinations of leptin and LPS. Data shows that leptin alone will not induce inflammatory mediators. However, increased induction of IL-6 was observed in a synergistic manner involving both LPS and leptin in an IRAK-1 dependent manner causing a robust inflammatory response. With regard to the effect of low dose LPS, we observed that human monocytic cells treated with low concentrations of LPS showed a mild yet sustained induction of proinflammatory cytokines, which is contrast to the robust and transient induction of cytokines by a high dose LPS. To further determine the molecular mechanisms, we measured several key signaling molecules that include IRAK-1, IKKepsilon, and C/EBPdelta. Our study revealed a novel mechanism that appears to be distinct from the traditional NFï «B pathway responsible for the effect of low dose LPS. / Ph. D.