Fundação Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro / Avaliar os efeitos benéficos do tratamento com óleo de peixe sobre mudanças metabólicas e morfológicas no pâncreas e tecido adiposo de camundongos C57BL/6 alimentados com dieta rica em lipídeos e sacarose (HLS).Camundongos machos da linhagem C57BL/6, foram alimentados com dieta padrão (P) ou dieta HLS. Aos 3 meses de idade, os camundongos do grupo HLS foram separados em grupo não-tratado (HLS) ou grupo tratado com óleo de peixe (HLS-Px, 1,5g/kg/dia). Aos 4 meses de idade os animais foram sacrificados. O grupo HLS apresentou aumento da massa corporal (MC) e no acúmulo do tecido adiposo total, porém o grupo HLS-Px apresentou menor MC e massa de tecido adiposo comparado ao grupo HLS. As concentrações de glicose plasmática e insulina não foram afetadas entre os grupos, no entanto os grupos HLS e HLS-Px apresentaram maior HOMA-IR. Os grupos HLS e HLS-Px apresentaram maiores concentrações plasmáticas do colesterol total e LDL-C, porém o grupo HLS-Px apresentou maior concentração plasmática do HDL-C e redução da concentração de triglicerídeos. Os adipócitos do grupo HLS apresentaram maior diâmetro quando comparado aos grupos controle e HLS-Px. A massa do pâncreas foi menor no grupo HLS-Px e as ilhotas pancreáticas apresentaram maior diâmetro no grupo HLS, quando comparado ao grupo controle. A expressão de insulina, glucagon e GLUT-2 mostrou-se forte em todas as ilhotas pancreáticas do grupo controle, mas o grupo HLS apresentou fraca expressão para o GLUT-2. Entretanto, HLS-Px apresentou maior expressão do GLUT-2. O tratamento com óleo de peixe foi capaz de reduzir o ganho de massa corporal e a concentração de triglicerídeos, assim como reduzir o acúmulo de tecido adiposo,hipertrofia dos adipócitos, das ilhotas pancreáticas, assim como prevenir a redução do GLUT-2 em camundongos C57BL/6. / To evaluate the fish oil treatment upon morphological and metabolic changes in the pancreas and adipose tissue of C57BL/6 mice fed high-fat-high-sucrose (HFHS) diet. Male C57BL/6 mice were fed HFHS chow or standard chow (SC). At 3 mo-old, HFHS mice were separated into untreated group (HFHS) or treated with fish oil (HFHS-Fo, 1.5 g/kg/day). At 4-mo-old animals were sacrificed. HFHS had increase in body mass (BM) and in total body fat, but HFHS-Fo had smaller BM and total body fat in relation to HFHS. Plasma glucose and insulin levels were not affected among the groups, but HFHS and HFHS-Fo had higher HOMA-IR ratio. HFHS and HFHS-FO had increased plasma total cholesterol and LDL-C, but HFHS-Fo increased plasma HDL-C and decreased triglycerides levels. The adipocytes size were greater in HFHS, when compared to SC and HFHS-Fo groups. HFHS-Fo had smaller pancreas mass and HFHS presented higher islet pancreatic diameter, when compared to SC group. SC group showed strong expression for insulin, glucagon and GLUT-2 in all pancreatic islets, and HFHS presented lesser expression for GLUT-2. However, HFHS-Fo presented increase of GLUT-2 expression. Fish oil treatment was able to reduce body mass gain and plasma TG, reduce fat pad adiposity as well as adipocyte and pancreatic islet hypertrophy, prevent decrease GLUT-2 in C57BL/6.

Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro / O objetivo deste trabalho foi estudar a ação do fenofibrato, um agonista do receptor ativador da proliferação peroxissomal alfa, no remodelamento cardíaco e na expressão de componentes do sistema renina-angiotensina (SRA) em um modelo de obesidade induzida por dieta. Camundongos machos C57Bl/6 com três meses de idade foram alimentados durante 11 semanas com dieta controle (grupo C, 3,57 kcal/g de dieta) ou dieta hiperlipídica (grupo HL, 5,40 kcal/g de dieta), em seguida foram separados em quatro grupos e estudados durante cinco semanas: C; HL; C-L (C mais fenofibrato) e HL-F (HL mais fenofibrato). Os animais HL foram mais pesados e apresentaram maior pressão arterial (PA) comparados aos animais C, mas HL-F foram mais leves e tiveram PA menor que HL. A resistência insulínica vista nos camundongos HL foi melhorada com fenofibrato nos camundongos HL-F. Fenofibrato reduziu colesterol total, triglicerídeos e aumentou HDL-c. Os animais HL apresentou um ventrículo esquerdo (VE) mais pesado e com espessura da parede maior, como também cardiomiócitos maiores e uma menor razão cardiomiócito/capilares que os animais C. Fenofibrato foi eficiente em melhorar estas alterações. As expressões cardíacas de Angiotensina II (ANG II) e de seu receptor tipo 1 (AT1R) foram maiores, enquanto que a expressão de seu receptor tipo 2 (AT2R) foi menor nos animais HL que nos animais C, e fenofibrato foi eficiente em atenuar estas diferenças. Como conclusão, a dieta HL lidera para a obesidade, elevação da PA, hipertrofia cardíaca, alterações metabólicas e expressão proteica alterada do SRA em camundongos, sugerindo a participação do SRA nestas alterações. Fenofibrato é eficiente em diminuir a PA e controlar a expressão proteica do SRA, assim como no tratamento da resistência insulínica e do remodelamento cardíaco adverso, diminuindo a hipertrofia dos cardiomiócitos e melhorando a vascularização do miocárdio, desta maneira, diminuindo importantes fatores de risco para doenças cardiovasculares / The aim was to study the action of fenofibrate, a peroxisome proliferator-activated receptor alpha agonist, in cardiac remodeling and protein expressions of RAS components in a model of obesity induced by diet. 3-mo-old C57BL/6 male were fed for 11 weeks with standard chow (SC group, 3.57 kcal/g of chow) or high-fat chow (HF group, 5.40 kcal/g of chow), then they were separated into four groups and studied for five weeks: SC; HF; SC-F (SC plus fenofibrate) and HF-F (HF plus fenofibrate). HF was heavier and had higher blood pressure (BP) than SC, but HF-F was lighter and had lower BP than HF. The insulin resistance seen in HF mice was corrected by fenofibrate in HF-F mice. Fenofibrate reduced total cholesterol, triglycerides and raised the HDL-c. HF had thicker and heavier left ventricle (LV) with bigger LV cardiomyocyte and smaller cardiomyocyte-to-capillaries ratio than SC, and fenofibrate was efficient in treating these alterations. Cardiac expressions of angiotensin II (ANG II) and ANG II receptor 1 were higher, and ANG II receptor 2 was lower in HF than in SC, and fenofibrate was efficient in attenuating these differences. In conclusion, HF diet leads to obesity, BP elevation, cardiac hypertrophy, metabolic changes and altered RAS protein expression in mice, suggesting that RAS is involved. Fenofibrate is efficient in decreasing BP and in controlling RAS protein expressions, and treats the insulin resistance and the adverse cardiac remodeling decreasing the cardiomyocyte hypertrophy and improving the myocardial vascularization, therefore, decreasing important cardiovascular risk factors

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Este estudo teve como objetivo avaliar o papel da administração crônica de cafeína durante a gestação de camundongos C57BL/6 sobre o remodelamento cardíaco e a expressão de componentes do sistema renina-angiotensina (SRA) na prole macho adulta. Fêmeas C57BL/6 grávidas foram divididas em dois grupos (n = 10): grupo controle (C), progenitoras foram injetadas apenas com o veículo (solução salina NaCl 0,9%), e grupo cafeína (CF), progenitoras receberam diariamente uma injecção subcutânea contendo 20 mg/kg de cafeína (1 mg/ml de solução salina). Após o desmame, os filhotes tiveram livre acesso à ração padrão até 90 dias de idade quando foram sacrificados. Rim e ventrículo esquerdo (VE) foram coletados para análise estrutural e western blotting. O grupo cafeína mostrou uma redução significativa no ganho de massa corporal (MC) (-18%; P <0,0001). O grupo cafeína apresentou ainda um aumento da pressão arterial sistólica (+ 48%; P <0,0001) e freqüência cardíaca (+10%; P <0,01) em relação ao grupo controle. A massa do VE corrigida pela MC no grupo da cafeína foi maior que no grupo C (+10%; P <0,01). O grupo cafeína apresentou um aumento na área de cardiomiócitos (+40%; P <0,05), e reduzida densidade capilar (-25%; P <0,05). No rim, as expressões de renina (128%; P <0,05) e dos receptores 1 da angiotensina II (AT1R) (88%; P <0,05) foram significativamente maiores nos animais do grupo cafeína. No VE, o grupo cafeína demonstrou aumento da expressão de ECA (+30%; P <0,05), angiotensina II (+60%; P <0,01), e AT1R (+77%; P <0,01) e diminuição da expressão do receptor 2 de angiotensina II (-46%; P <0,05). Em conclusão, a administração crônica de cafeína durante a gestação, possivelmente programa a expressão de componentes de sistema renina-angiotensina, levando à ativação persistente do SRA renal e cardíaco local, que por sua vez promove o aumento da pressão sanguínea, remodelação e efeitos cardíacos adversos. / This study aimed to evaluate the role of caffeine chronic administration during gestation of C57BL/6 mice on cardiac remodeling and the expression of components of the renin-angiotensin system (RAS) in male offspring as adults. Pregnant C57BL/6 female mice were divided into two groups (n=10): Control group (C), dams were injected with the vehicle only (saline 0.9% NaCl), and Caffeine group (CF), dams received daily a subcutaneous injection containing 20 mg/kg of caffeine/day (1 mg/ml saline). After weaning, pups had free access to the standard chow until 90 days of age when they were killed. Kidney and left ventricle (LV) were collected for structural analysis and Western blot. Caffeine group showed a significant reduction in body mass (BM) gain (-18%;P<0.0001). Caffeine group had increased systolic blood pressure (+ 48%;P<0.0001) and higher heart rate (+10%;P<0.01) than control group. LV mass adjusted by BM in caffeine group was greater than in C group (+10%;P<0.01). Caffeine group had increase in the area of cardiomyocytes (+40%;P<0.05), and reduced capillary density (-25%;P<0.05). In the kidney, the expressions of renin (+128%; P<0.05) and angiotensin II receptor 1(AT1R) (+88%;P<0.05) were significantly greater in caffeine mice. In the LV, caffeine group showed increased expression of ACE (+30%; P <0.05), angiotensin II (+60%;P<0.01), and AT1R (+77%;P<0.01), and decreased expression of angiotensin II receptor 2 (-46%;P<0.05). In conclusion, chronic administration of caffeine during gestation possibly programs the expression of renin-angiotensin system components, leading to persistent activation of local renal and cardiac RAS, which in turn promotes increased BP and adverse cardiac remodeling.

A doença de Huntington (DH) é um distúrbio neurodegenerativo hereditário e autossômico dominante e tem como características alterações motoras e mentais progressivas. Recentemente, além das alterações verificadas no sistema nervoso central, também têm sido descritas alterações em órgãos periféricos, tais como osteoporose, atrofia muscular, problemas intestinais, alterações cardíacas e, sobretudo, alterações no sistema nervoso autônomo. São evidentes as alterações autonômicas do coração nos portadores da DH, as quais, são, sobretudo, um risco potencial, tornando os pacientes suscetíveis a problemas cardiovasculares. No entanto, os mecanismos pelos quais a doença afeta os componentes autonômicos do coração não são totalmente conhecidos, por isso a importância de se estudar os componentes da inervação cardíaca, sobretudo o gânglio estrelado (GE). A DH pode ser induzida através do ácido 3-nitropropiônico (3-NP), pois essa substância produz efeitos neurotóxicos inibindo a succinato desidrogenase. Esta pesquisa objetiva analisar, por meio da indução através do 3-NP, os efeitos da DH no GE, identificando possíveis alterações morfoquantitativas dos neurônios ganglionares, com uso de técnicas baseadas em delineamento estereológico 3D e de bioimagem associadas à teste comportamental e perfil hemodinâmico, a fim de contribuir para o entendimento de como a doença age na inervação do coração. Para isso foram utilizados 14 camundongos C57BL-6 machos que foram alocados em dois grupos: Grupo Controle com 7 animais induzidos com solução salina (0,9%); Grupo 3NP com 7 animais induzidos com doses subagudas de 60 mg.kg-1dia-1 de 3-NP. Foram realizados o teste comportamental, a avaliação cardíaca e a análise estereológica. Os principais achados dessa pesquisa foram: (I) diminuição da atividade exploratória dos animais; (II) prejuízo da função sistólica; (III) aumento de 76% no volume ganglionar; (IV) aumento de 70% no volume médio dos neurônios, concluindo-se que o 3-NP produz efeitos na função cardíaca, ocasionando hipertrofia do gânglio / Huntington\'s disease (HD) is a hereditary and autosomal dominant neurodegenerative disorder and is characterized by progressive motor and mental changes. Recently, in addition to changes in the central nervous system, alterations in peripheral organs such as osteoporosis, muscular atrophy, intestinal problems, cardiac alterations and, above all, changes in the autonomic nervous system have also been described. Autonomic heart alterations in DH patients are evident, which are a potential risk, making patients susceptible to cardiovascular problems. However, the mechanisms by which the disease affects the autonomic components of the heart are not fully understood, therefore, the importance of studying the components of cardiac innervation, especially the stellate ganglion (SG). HD can be induced through 3-nitropropionic acid (3-NP), as this substance produces neurotoxic effects inhibiting succinate dehydrogenase. The aim of this research was to analyze the effects of HD on the SG by means of 3-NP induction, identifying possible morpho-quantitative changes in ganglion neurons, using techniques based on 3D stereological and bioimaging techniques associated with behavioral and hemodynamic profile, In order to contribute to the understanding of how the disease acts in the heart innervation. For this, 14 male C57BL-6 mice were used, which were allocated in two groups: Control Group with 7 animals induced with saline solution (0.9%); Group 3NP with 7 animals induced with subacute doses of 60 mg.kg-1day-1 of 3-NP. Behavioral test, cardiac evaluation and stereological analysis were performed. The main findings of this research were: (I) decrease in the exploratory activity of the animals; (II) impairment of systolic function; (III) 76% increase in ganglion volume; (IV) increase of 70% in the mean volume of the neurons, concluding that 3-NP produces effects on cardiac function, causing hypertrophy of the ganglion

Ao longo dos processos de imortalização e transformação maligna, as células adquirem inúmeras alterações genéticas, que são causadas por fatores endógenos e exógenos como agentes biológicos e a geração de espécies reativas de oxigênio. Neste trabalho, uma linhagem celular espontaneamente transformada foi clonada a partir de explantes de embriões de camundongos C57bl/6. Esta linhagem mostrou-se produtora de pigmento escuro; a análise citoquímica e ultraestrutural permitiu caracterizar a linhagem como tendo origem melanocítica. A linhagem, denominada Mgal3, mostrou-se tumorigênica quando implantada no tecido subcutâneo de animais singenéicos, apresentando capacidade de disseminação linfática, dando origem a metástases em linfonodos, o que permitiu caracteriza-la como uma linhagem de melanoma murino. O processo de transformação deste melanoma caracterizou-se pela expressão de genes retrovirais endógenos, com expressão do antígeno associado a melanoma (MAA), reconhecido pelo anticorpo monoclonal MM2-9B6; ausência de mutações nos exons 5 a 8 do gene supressor de tumor TP53; e, silenciamento do gene CDKN2a, que codifica duas proteínas que atuam em redes de supressão de tumores, p16INK4a e p19ARF. A perda de expressão de pelo menos um destes produtos gênicos parece associada a mecanismos epigenéticos, uma vez que o tratamento de Mgal3 com o inibidor de DNA metiltransferase 5-Aza-2-deoxicitidina, restaurou a transcrição de pelo menos um dos transcritos do gene CDKN2a. Da mesma forma, observamos que o gene LGALS3, que codifica a lectina animal galectina-3 também é silenciado nesta linhagem, mostrando que esta molécula não está associada à manutenção desta célula transformada em condições de cultivo. / A novel murine melanoma cell line named Mgal3 was generated from embryo explants. This cell line gave rise to metastatic tumors when injected subcutaneously in C57bl/6 mice. Tumor histogenesis was determined at the cytochemical (Fontana Masson staining), immunohistochemical (staining with anti-HMB45 and anti-S100) and ultrastructural levels. Mgal3 produces high amounts of retroviral C particles and was recognized by the mAb MM2-9B6, which reacts with a melanoma associated antigen derived from the envelope of the ecotropic retrovirus MelArv. No mutations were found in TP53 exons 5-8, however loss of CDKN2a expression was observed. Treatment of Mgal3 with the demethylating agent azadeoxycytidine indicated that at least one of the genes encoded at the CDKN2a locus was silenced by promoter hypermethylation. Furthermore, this cell line did not express the animal lectin, galectin-3. The galectin-3 gene promoter seemed to be hypermethylated, since treatment of Mgal3 with azadeoxycytidine led to the de novo expression of the lectin.

Breast cancer is the most common cancer type with a high annual death rate. Finding meaningful tissue-related or body-fluid-accessible biomarkers is necessary to characterize cancer subtype, predict tumor behavior, choose the most effective therapy, predict severe treatment-related toxicities, and also the opportunity to personalize treatments for each patient. There is increasing evidence that various kallikrein-related peptidases (Klk) gene family members can modulate the immune response and are differentially regulated in breast cancer, and therefore are proposed to be potential prognostic biomarkers. This work established and validated an experimental setup to study the roles of selected kallikrein-related peptidases (KLK5, KLK7, KLK14) in breast cancer in vivo using gene-deficient mouse models previously generated in our laboratory. We used the CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats) editing system to generate several E0771 cell line-based reporter and gene-deficient cell lines. These allowed enhanced monitoring of cancer progression in vivo and studying KLKs roles in tumor immune microenvironment of C57Bl/6N mice. Finally, we present the analysis of the initial in vivo experiments using these tools combined with established Klk-deficient mouse models. Our...

The 129S2 inbred mouse strain is often used as a background strain in the production of genetically altered mice (i.e. knockout and transgenic mice). It is important to establish the behavioral phenotype of wild-type mice before making comparisons to genetically altered mice. Also, those comparisons can assist in the evaluation and interpretation of the in vivo effects of drugs. The drug discrimination assay measures the subjective effects of drugs and provides a measure of underlying neuropharmacological mechanisms responsible for the discriminative stimulus properties of drugs. The present study established the atypical antipsychotic drug clozapine as a discriminative stimulus in male 129S2 inbred mice and compared clozapine’s discriminative stimulus properties in 129S2 mice to C57BL/6 and DBA/2 inbred mice. By comparing the discriminative stimulus properties between inbred strains of mice we hope to obtain a fuller picture of the underlying neuropharmacological mechanisms of antipsychotic drugs.

Due to its unique receptor binding profile and its relationship to clozapine, N-desmethylclozapine (NDMC) has been examined as a possible antipsychotic drug (APD). Clozapine has been trained as discriminative stimulus in our lab, but NDMC has not yet been established as a discriminative stimulus. In experiment 1, 12 C57BL/6 mice were trained to discriminate 10.0 mg/kg NDMC from VEH using a standard-two lever operant procedure to assess antipsychotic substitution. The typical APD clozapine fully substituted for NDMC at 2 doses tested (2.5 and 5.0 mg/kg), while typical APD haloperidol failed to substitute for NDMC. In Experiment 2, 11 mice were given repeated administration of NDMC to assess cross-tolerance development to the discriminative stimulus of clozapine. NDMC was successfully trained as a discriminative stimulus and was also shown to induce cross-tolerance to clozapine’s discriminative stimulus, indicating similar underlying pharmacological mechanisms of action between NDMC and clozapine.

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Macrophages are phagocytic cells of the innate immune system, which have a central role in immune surveillance, tissue homeostasis and the immune response to bacterial, viral, protozoan and helminth parasites. It is now appreciated that many tissue resident macrophage (resMΦ) populations, including those in the peritoneal and pleural cavity, are derived prenatally prior to the establishment of definitive haematopoiesis in the bone marrow. Once seeded, these resMΦ populations are long-lived and capable of self-renewal via in situ proliferation driven by CSF-1. An inflammatory insult, such as bacterial infection, results in the recruitment of bone marrow derived macrophages (BMDMΦ) and the disappearance of the resMΦ population. BMDMΦ recruited to the site of infection become classically activated upon engagement of pathogen recognition receptors and subsequent STAT1 induction. Classically activated macrophages (CAMΦ) are highly bactericidal through the production of inflammatory cytokines, which direct the TH1 immune response, and upregulation of iNOS to generate high concentrations of intracellular nitric oxide. During resolution of acute inflammation resMΦ undergo a CSF-1 driven proliferative burst to repopulate the tissue. In contrast to bacterial infection, helminth parasites drive a TH2 immune response characterised by CD4+ T cell production of IL-4, which induces proliferation and alternative activation of the resMΦ population, thereby overcoming the need for an inflammatory influx of BMDMΦ. Alternatively activated macrophages (AAMΦ) are generated through signalling from the IL-4Rα subunit and subsequent expression of the molecules RELMα, YM1 and arginase-1. While both BMDMΦ and resMΦ upregulate RELMα, YM1 and Arg-1 in response to IL-4Rα stimulation, microarray analysis revealed an otherwise diverse transcriptional and cell surface phenotype between these populations. It was hypothesised that the diverse modes of macrophage accumulation enlisted by bacterial and helminth parasites, combined with the distinct alternative activation phenotypes employed by BMDMΦ and resMΦ populations would translate into important functional differences as regards anti-parasitic immunity. Chapter 1 and 2 of this thesis addresses the importance of macrophage origin during infection with the filarial nematode Litomosoides sigmodontis, taking advantage of the naturally occurring resistant C57BL/6 and susceptible BALB/c strains. A large disparity in MΦ accumulation was observed throughout the infection time course, with significantly larger numbers present within the pleural cavity of resistant C57BL/6 mice. This difference in MΦ number was a reflection of enhanced F4/80hi resMΦ accumulation. Through Ki67hi staining and the use of CCR2-/- and partial bone marrow chimeric mice, the expanded F4/80hi population in resistant C57BL/6 mice was shown to be a result of proliferation of the local F4/80hiGATA6+CD102+ resMΦ population. A high degree of BMDMΦ incorporation into the resMΦ pool through assumption of an F4/80hiGATA6+CD102+ phenotype was observed in both naïve and infected bone marrow chimeric animals, supporting a recent publication showing gradual incorporation of these cells into the resMΦ niche with age. Importantly, the degree of BMDMΦ incorporation into the F4/80hi population was equivalent between naïve and infected animals, despite a 27-fold difference in cell number, illustrating that expansion is a result of proliferation of local resMΦ, independent of origin. Susceptibility was marked by reduced resMΦ proliferation and enhanced recruitment of bone marrow derived F4/80lo MΦ and monocytes. These recruited BMDMΦ displaced the resMΦ population, failed to integrate the resMΦ niche and were highly positive for PD-L2, a marker specific to BMD AAMΦ. Prevention of monocyte influx and subsequent resMΦ displacement resulted in increased worm killing and a stronger TH2 immune response in susceptible BALB/c mice, thereby confirming a detrimental role for BMD AAMΦ in worm killing. Conversely, in order to confirm a protective role for the expanded resMΦ in resistant C57BL/6 mice we attempted to deplete the resMΦ population through intrapleural delivery of clodronate-loaded liposomes. Due to technical issues we were unable generate statistically significant results when depleting the resMΦ population, however a trend toward decreased worm killing in the absence of resMΦ is evident. Previously generated microarrays in the lab identified the complement cascade as being highly upregulated by AAMΦ induced in response to Brugia malayi infection compared to BMDMΦ (thioglycollate elicited). To investigate the role of complement in resistance to L. sigmodontis, Chapter 3 briefly phenotypes the macrophage compartment of C3-/- C57BL/6 mice during infection. No differences in worm burden or macrophage phenotype could be detected in C3-/- mice compared to WT controls, however this may be explained through differences in strain or MΦ origin. This chapter provides an important foundation for future studies on complement and its role in worm killing during L. sigmodontis infection. The final chapter of the thesis focuses on examining the bactericidal capabilities of BMD and resMΦ populations. An in vitro system was utilised to assess the interaction of bone marrow derived macrophages (thioglycollate elicited) and ResMΦ (from naïve mice) with Salmonella enterica serovar Typhimurium SL3261. I found that in vitro BMDMΦ are infected by/ingest SL3261 to a much greater degree than resMΦ. The resMΦ population is less efficient at both controlling the spread and killing intracellular SL3261 overtime, compared to the BMDMΦ population. In vivo however, there appears to be no difference in the ability of the monocyte derived F4/80lo MΦ and the F4/80hi resident MΦ to be infected by/ ingest SL3261, nor was a difference in bactericidal ability detected. Ultimately my work highlights that the anti-parasitic functions of MΦ populations are not dictated by origin but rather the activation phenotype upon infection and ability to respond to local stimuli.