The human monocyte-derived THP-1 cell line was incubated with 10mM AAPH in Earle’s Balanced Salt Solution at 37°C for up to 24 hours. Protein hydroperoxide formation occurred after an 8 hour lag phase which corresponded to glutathione loss observed in the cells. SDS-Page analysis confirmed protein degradation occurred after 6 hours. Cell viability measured by the MTT reduction assay also dropped after 8 hours. Reduction of intracellular glutathione levels using BSO caused reduction of the lag phase seen in protein hydroperoxide formation. Cell viability of BSO-treated cells was lower than control cells, indicating the initiation of apoptotic events. Flow cytometry analysis showed no difference between BSO-treated and control cells, indicating that GSH levels do not have an effect on the type of cell death observed in AAPH-induced oxidative damage on THP-1 cells. These results confirmed previous data in the lab suggesting THP-1 cells undergo AAPH-induced necrosis as a result of cellular damage, including the loss of GSH and the formation of protein hydroperoxides.

La protéine C-réactive (CRP) est aujourd’hui considérée comme un biomarqueur indispensable dans la prédiction de maladies cardio-vasculaires et de complications aiguës associées, et ce, par des mécanismes qui ne sont pas encore totalement élucidés. Nous avons étudié les effets de la CRP dans divers aspects de la biologie des cellules mononucléaires du sang périphérique (PBMC) et des monocytes humains ex vivo. En effet, ces cellules peuvent être impliquées dans la physiopathologie de ces maladies. Nous avons aussi utilisé la lignée promonocytaire THP-1. Ces trois types cellulaires ont été incubés avec la CRP purifiée ou recombinante et l’expression génique de cytokines pro-inflammatoires, de chimiokines et de MMP-9 a été analysée par PCR semi-quantitative en temps réel et l’expression protéique par test immunométrique ou par test ELISA. La CRP ne semble agir ni sur la synthèse de ces cytokines ni sur celle de MMP?9. Une approche globale par puce à protéines avec les surnageants de culture de monocytes a démontré que la CRP augmentait la synthèse du VEGF-A. Ce résultat a été confirmé au niveau transcriptionnel par RT-PCR et au niveau protéique par test ELISA. Une étude complémentaire avec la lignée THP-1 a permis de montrer l’implication des voies PI3?Kinase et MEK mais pas celle de la p38MAPKinase dans cette augmentation. Ces travaux ont ainsi permis la mise en évidence de plusieurs mécanismes permettant d’associer la CRP aux pathologies cardiovasculaires dans une relation de cause à effet. Ces mécanismes pourraient représenter des cibles thérapeutiques potentielles des maladies cardiovasculaires. / C-reactive protein is now considered as an essential biomarker for predicting the occurrence of cardiovascular diseases and their acute complications through mechanisms that are not fully elucidated. We investigated CRP effects on several aspects of the biology of ex vivo human peripheral blood mononuclear cells (PBMC) and monocytes. In fact, these cells can be involved in the pathophysiology of these diseases. Also, we used the promonocytic line THP-1. These three cellular types were incubated with purified or recombinant CRP and gene expression of pro-inflammatory cytokines, chemokines and (pro)MMP-9 was analysed by real time semi-quantitative PCR and protein expression by immunometric or ELISA tests. CRP doesn’t seem to act upon neither the tested cytokines synthesis nor the (pro)MMP-9 expression. A global approach by protein array with the cultured monocytes supernatants showed that CRP induced VEGF-A protein synthesis. This result was confirmed at transcriptional level by RT-PCR and at protein level by ELISA. A complementary study with the monocytic cell line THP-1 demonstrated the activation of PI3-Kinase and MEK pathways but not of p38MAPKinase pathway in this regulation. These results provide insight into several mechanisms that could transform the statistical association between CRP and cardiovascular diseases into a cause-to-effect relationship. Some of these mechanisms could represent therapeutic targets for cardiovascular diseases.

Thesis advisor: Kenneth C. Williams / Elucidating the mechanisms through which viral infection and persistence in CNS occurs is critical to understanding the development and progression of neurological disease. To date, no study has demonstrated that monocyte traffic in HIV and SIV infection directly results in neuronal injury. The central hypothesis in this thesis is that continuous trafficking of monocytes into tissues is essential for pathogenesis with viral infection. In the dissertation work presented here, two studies addressed this hypothesis. In Chapter 2, experiments examining the role of peripheral monocyte activation in the development of neuroAIDS using the tetracycline antibiotic minocycline will be described. We hypothesized that decreased monocyte activation with minocycline treatment would play a neuroprotective role in the context of rapid SIV infection with a high incidence of SIV encephalitis (SIVE). We observed a reversal of neuronal injury within days of minocycline treatment that correlated with loss of monocyte activation. From these findings we concluded that decreased activation of monocytes results in lower CNS traffic. However this effect may have occurred due to lower plasma virus, decreased SIV infection of monocytes, or the ability of minocycline to cross the BBB and modulate changes within the CNS directly. In Chapter 3 of this thesis, we hypothesized that continuous traffic of activated monocytes from the periphery into the CNS is required for neuronal injury with AIDS, and that by effectively stopping monocyte accumulation, CNS pathology can be blocked or reversed. We also hypothesized that monocyte trafficking is necessary for the seeding of brain and small intestine with cell-associated virus. In order to test these hypotheses, we utilized the anti-α4 blocking antibody natalizumab (Tysabri; Biogen Idec), which selectively binds to the α4 subunit of α4β1 (VLA-4) and α4β7 integrins, preventing the interaction between α4 and its various ligands. To address the first hypothesis, natalizumab was administered after four weeks of infection once significant neuronal damage had already occurred. We found that preventing cell traffic with natalizumab is sufficient to stabilize neuronal injury and loss, demonstrating conclusively that stopping monocyte traffic stabilizes CNS disease. To address the second hypothesis, rhesus macaques were treated with natalizumab on the day of SIV infection. Natalizumab treatment completely blocked SIV infection in the brain, and virus traffic to the small intestine was significantly suppressed. Overall, these studies demonstrate that continuous traffic of monocytes is required for neuronal injury and the formation of CNS lesions, and that early trafficking of leukocytes is critical for seeding of the CNS and contributes to seeding of the small intestine with virus. / Thesis (PhD) — Boston College, 2014. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Biology.

Physiological inflammation occurs in the female reproductive tract, but pathological inflammation is implicated in reproductive pathologies such as preterm labour and endometrial cancer. Preterm labour (PTL, before 37 weeks of gestation) is the leading cause of preterm birth, neonatal mortality and perinatal morbidities. Endometrial cancer is the commonest gynaecological cancer, and its pathogenesis is characterised by chronic inflammation. The overall aims of this thesis were (i) to develop an in vitro model of myometrial-monocyte interactions to replicate the events occurring in the myometrium in preterm labour (ii) to determine the effects of potential therapeutics such as lipoxins, IL-10 and progesterone, on inflammation, and (iii) to characterise the lipoxin pathway in endometrial adenocarcinoma. Macrophages infiltrate the pregnant myometrium during labour; however the role of these cells is unclear. A myometrial-monocyte coculture model was developed either using non-pregnant primary myometrial smooth muscle cells (UtSMCs), or immortalised pregnant human myometrial cells (PHM1-41), with primary monocytes from term (38-41 weeks of gestation), non-labouring pregnant women. Cultures were stimulated with the toll-like receptor 4 agonist lipopolysaccharide (LPS), in the presence or absence of each of lipoxins, IL-10 and progesterone. A significant and synergistic increase in IL-6 and IL-8 secretion was found in the UtSMC/monocyte coculture after stimulation with LPS for 24 hours, compared to LPS-treated UtSMCs, or monocytes alone, but the increase in IL-6 and IL-8 secretion was not inhibited by lipoxin, epi-lipoxin or benzo-lipoxin. The PHM1-41/monocyte coculture both alone and in response to LPS treatment generated significantly increased IL-6 and IL-8 secretion, compared to vehicle treatment in the coculture and compared to the culture of either cell type alone. IL-1β and TNFα secretion were only detected from the PHM1/monocyte coculture, and monocytes alone. Use of a TNFα blocking antibody partially suppressed LPS-induced IL-6 and IL-8 secretion in the coculture. Coculture of PHM1/monocytes resulted in increased secretion of multiple mediators including pro-inflammatory cytokines, chemokines and growth factors compared to culture of either PHM1 cells or primary monocytes separately, both with vehicle and with LPS. IL-10 inhibited LPS-induced IL-6 and IL-8 secretion from the coculture, as did progesterone, which also inhibited GM-CSF, MCP-1 and CXCL5 secretion. Myocyte contraction, measured by PHM1-41 cells embedded in collagen was increased by primary monocyte treatment. This suggests that not only do infiltrating monocytes increase myometrial inflammation but they can induce myometrial smooth muscle contraction. In endometrial adenocarcinoma, the lipoxin synthesis enzymes, ALOX-5 and -15 and FPR2 mRNA expression were upregulated compared to proliferative phase endometrium, with FPR2, a reported lipoxin receptor, immunolocalised in endometrial adenocarcinoma tissue. Additionally, TNFα treatment of Ishikawa endometrial adenocarcinoma cells increased FPR2 mRNA expression, and upregulation of FPR2 mRNA also occurred in xenograft tumours from CD1 nude mice, compared to the Ishikawa cells from which they originated. These findings highlight FPR2 expression in endometrial adenocarcinoma, and suggest this receptor could mediate inflammatory signals, and lipoxins could be produced by ALOX-5 and ALOX-15. Collectively, these data describe the novel effects of monocytes in the regulation of myometrial smooth muscle cell inflammation, and demonstrate a mechanism by which myometrial inflammation during both term and preterm labour is triggered by infiltrating macrophages. This myocyte/monocyte inflammation is regulated in part by TNFα, and can be suppressed by both IL-10 and progesterone co-treatment. Components of the lipoxin pathway are present in endometrial adenocarcinoma, but their role in regulation of inflammation is still to be elucidated. Future research to clarify the processes, by which leukocyte recruitment is regulated at labour and the role of monocyte/macrophages in altering myocyte properties, could help to elucidate the mechanisms coupling inflammation to labour and provide more appropriate targets for the treatment of PTL.

ABSTRACT Alzheimer's disease (AD) is the most common progressive age related dementia and the fourth major cause of mortality in the elderly in the United States. AD is pathologically characterized by deposition of amyloid beta (Aβ) plaques in the brain parenchyma and neurofibrillary tangles (NFTs) within the neuronal soma. While pharmacological targets have been discovered, current strategies for the symptomatic or disease-modifying treatment of AD do not significantly slow or halt the underlying pathological progression of the disease. Consequently, more effective treatment is needed. One possibility for amelioration is using human umbilical cord blood cell (HUCBC) therapy. HUCBCs comprise a population of hematopoietic stem and progenitor cells. During recent years, functional recovery has been observed from the use of HUCBCs in pre-clinical animal models of brain and spinal cord injuries. Thus, modulation by cell therapy, specifically HUCBCs, may be a suitable treatment for AD and other models because of the observed cognitive and behavioral improvements. The studies presented in this dissertation centers on the suitability of using HUBCs as a potential treatment for AD. Expanding on this, the aims of the study sought to: (I) Investigate bio-distribution of HUCBC transplantation in PSAPP mice, (II) Characterize efficacy and determine therapeutic outcome of HUCBC following short and long term multi injections at early and late disease stages in PSAPP mice and (III) Determine AD-like pathological and cognitive changes associated with multiple HUCBC-derived monocyte (CD14) injections in PSAPP mice. Thus the findings of this work evolved from experiments that characterized the effects of low-dose infusions of HUCBC and HUCBC-derived monocytes into 6 month old Presenilin 1/Amyloid Precursor Protein (PSAPP) plaque-developing transgenic AD mice. Treated mice were studied using standard behavioral tests to determine the effects of infusion on the multiple cognitive domains affected by AD, followed by biochemical and histological analyses that included Aβ load and amyloid precursor protein (APP) processing. Specifically, PSAPP mice and their wild-type (WT) littermates were treated monthly with a peripheral HUCBC infusion over a period of 6 and 10 months, followed by cognitive and motor evaluation. Additionally, based on reports that tumor cells can originate from stem cells present in HUCB, we further examined whether monocytes purified from HUCBCs would have a similar significant effect on the reduction of AD-like pathology in PSAPP mice. HUCB cells homed into tissues including the brain. The principal finding was significant reduction in Aβ levels and β–amyloid plaques following low-dose infusions of both HUCBC– derived mononuclear cells as well as HUCBC-derived monocytes, with the monocytes providing a stronger effect. Results further demonstrated that HUCBC and HUCBC– derived monocyte infusion could improve memory function and locomotor ability in treated PSAPP mice. A possible reason for behavioral improvements in these animals may be the significant reduction in both Aβ levels and plaque load. This study also identified significant reduction in microglial activation and astrocytosis, both of which can contribute to AD pathology. In conclusion, our data suggest that it might be the HUCBC–derived monocytic population rather than stem cells that are responsible for the reduction in AD pathology.

Neutrophils are implicated in many inflammatory lung disorders. However, the mechanisms regulating neutrophil migration in acute lung inflammation are incompletely understood. Although, integrin β2 mediates neutrophil migration in lungs in response to many stimuli such as E. coli, integrin involved in <i>S. pneumoniae</i> induced neutrophil migration is not known. Therefore, the role of integrin αvβ3 in neutrophil recruitment was tested. First, it was found that the number of neutrophils expressing the integrin subunits αv and β3 is reduced or remains in lung inflammation induced by E. coli or <i>S. pneumoniae</i>, respectively. Next, the role of integrin αvβ3 using β3 knockout mice (β3-/-) and function blocking antibodies was addressed. Neutrophil recruitment did not vary between wild type and β3-/- mice. Although β3 antibodies reduced neutrophil recruitment, similar effect was observed with isotype antibodies. Therefore, one can conclude that integrin αvβ3 is not critical for neutrophil recruitment in <i>S. pneumoniae</i> induced pneumonia. <p>Apart from integrins, TLR4 also regulate neutrophil migration. Because, the pattern of TLR4 expression at various times of lung inflammation is not known, TLR4 expression during different phases of lung inflammation in a rat model of LPS-induced inflammation was studied. TLR4 expression in the septum increased and decreased at 6h and 12-36h of inflammation, respectively. Since these correlate with the time of increase and decline of neutrophil recruitment, the findings support previously observed requirement for TLR4 in neutrophil recruitment. <p>Neutrophils recruited into the lungs regulate the inflammatory process by controlling subsequent monocyte/macrophage recruitment. The mechanisms involved and the pattern of monocyte/macrophage recruitment in lungs are not completely understood. Therefore, the possible involvement of monocyte chemoattractant protein (MCP)-1, which is a premier chemokine in monocyte/macrophage migration and produced by neutrophils and other cells was tested. This was addressed by quantification of monocytes/macrophages at various times and using neutrophil depletion experiments in LPS-induced lung inflammation in rats. It was found that monocytes/macrophages migrate very early and before neutrophils in addition to their migration in the late phase of acute lung inflammation. Neutrophil depletion abrogated both early as well as the late monocyte/macrophage recruitment without altering the expression of MCP-1. Therefore, possibly other chemokines and not MCP-1 are involved in neutrophil dependent monocyte/macrophage recruitment. <p>To conclude, the experiments further the understanding on acute lung inflammation by ruling-out the involvement of integrin αvβ3 and MCP-1 in β2-independent neutrophil migration and neutrophil dependent monocyte/macrophage recruitment, respectively. Further studies are essential to find the integrins and chemokines operating in the above situations. Equally important will be to understand the functional significance of early recruited monocytes/macrophages in the lung.

Neutrophils are implicated in many inflammatory lung disorders. However, the mechanisms regulating neutrophil migration in acute lung inflammation are incompletely understood. Although, integrin β2 mediates neutrophil migration in lungs in response to many stimuli such as E. coli, integrin involved in <i>S. pneumoniae</i> induced neutrophil migration is not known. Therefore, the role of integrin αvβ3 in neutrophil recruitment was tested. First, it was found that the number of neutrophils expressing the integrin subunits αv and β3 is reduced or remains in lung inflammation induced by E. coli or <i>S. pneumoniae</i>, respectively. Next, the role of integrin αvβ3 using β3 knockout mice (β3-/-) and function blocking antibodies was addressed. Neutrophil recruitment did not vary between wild type and β3-/- mice. Although β3 antibodies reduced neutrophil recruitment, similar effect was observed with isotype antibodies. Therefore, one can conclude that integrin αvβ3 is not critical for neutrophil recruitment in <i>S. pneumoniae</i> induced pneumonia. <p>Apart from integrins, TLR4 also regulate neutrophil migration. Because, the pattern of TLR4 expression at various times of lung inflammation is not known, TLR4 expression during different phases of lung inflammation in a rat model of LPS-induced inflammation was studied. TLR4 expression in the septum increased and decreased at 6h and 12-36h of inflammation, respectively. Since these correlate with the time of increase and decline of neutrophil recruitment, the findings support previously observed requirement for TLR4 in neutrophil recruitment. <p>Neutrophils recruited into the lungs regulate the inflammatory process by controlling subsequent monocyte/macrophage recruitment. The mechanisms involved and the pattern of monocyte/macrophage recruitment in lungs are not completely understood. Therefore, the possible involvement of monocyte chemoattractant protein (MCP)-1, which is a premier chemokine in monocyte/macrophage migration and produced by neutrophils and other cells was tested. This was addressed by quantification of monocytes/macrophages at various times and using neutrophil depletion experiments in LPS-induced lung inflammation in rats. It was found that monocytes/macrophages migrate very early and before neutrophils in addition to their migration in the late phase of acute lung inflammation. Neutrophil depletion abrogated both early as well as the late monocyte/macrophage recruitment without altering the expression of MCP-1. Therefore, possibly other chemokines and not MCP-1 are involved in neutrophil dependent monocyte/macrophage recruitment. <p>To conclude, the experiments further the understanding on acute lung inflammation by ruling-out the involvement of integrin αvβ3 and MCP-1 in β2-independent neutrophil migration and neutrophil dependent monocyte/macrophage recruitment, respectively. Further studies are essential to find the integrins and chemokines operating in the above situations. Equally important will be to understand the functional significance of early recruited monocytes/macrophages in the lung.

<p>The fatty acid linoleic acid has been identified as a potential mediator of atherosclerotic plaque development. Treatment of monocytes with linoleic acid leads to an increase in monocyte adhesion to endothelial cells under flow conditions; however, the mechanisms through which linoleic acid affect monocyte adhesion remain unclear. Using a combination of micropipette aspiration techniques and fluorescent microscopy, I tested the hypothesis that linoleic acid increases membrane tether formation between monocytes and endothelial cells. </p><p>Treatment of U937 monocytes with free linoleic acid or albumin-bound linoleic acid reduced the cortical tension of the monocytes. The effects of albumin-bound linoleic acid on the membrane were governed by the exchange of linoleic acid from albumin to the membrane and by the removal of fatty acids from the membrane by fatty acid binding sites on albumin. </p><p>The frequency of tether formation between U937 monocytes and TNF-α stimulated HUVECs increased following treatment with free linoleic acid or albumin-bound linoleic acid. The increase in tether frequency was not due to an increase in monocyte deformability or adhesion receptor expression. Tether extraction occurred primarily through E-selectin. Treatment with free linoleic acid increased the localization of E-selectin to clathrin-coated pits suggesting an increase in the formation of nanoclusters of E-selectin on HUVECs. The increase in tether frequency was blocked by the U73122 phospholipase C inhibitor indicating that linoleic acid increased monocyte adhesion through a phospholipase C mediated mechanism.</p><p>Treatment with free linoleic acid did not affect the threshold force for tether extraction or the effective viscosity of tethers extracted from HUVECs, but it decreased the threshold force for tether extraction from U937 monocytes and increased the effective tether viscosity. Treatment with U73122 blocked the reduction in the threshold force indicating that linoleic acid affected the regulation of the membrane adhesion energy through the hydrolysis of PIP2 by phospholipase C.</p><p>The results of the study indicated that linoleic acid promoted membrane tether formation by increasing E-selectin bond formation and reducing the adhesion energy between the U937 plasma membrane and the actin cytoskeleton through the hydrolysis of PIP2 by phospholipase C.</p> / Dissertation

The human monocyte-derived THP-1 cell line was incubated with 10mM AAPH in Earle’s Balanced Salt Solution at 37°C for up to 24 hours. Protein hydroperoxide formation occurred after an 8 hour lag phase which corresponded to glutathione loss observed in the cells. SDS-Page analysis confirmed protein degradation occurred after 6 hours. Cell viability measured by the MTT reduction assay also dropped after 8 hours. Reduction of intracellular glutathione levels using BSO caused reduction of the lag phase seen in protein hydroperoxide formation. Cell viability of BSO-treated cells was lower than control cells, indicating the initiation of apoptotic events. Flow cytometry analysis showed no difference between BSO-treated and control cells, indicating that GSH levels do not have an effect on the type of cell death observed in AAPH-induced oxidative damage on THP-1 cells. These results confirmed previous data in the lab suggesting THP-1 cells undergo AAPH-induced necrosis as a result of cellular damage, including the loss of GSH and the formation of protein hydroperoxides.

Thesis (Ph.D.)--Baylor University, 2008. / In abstract "CD14highCD16+" the "high" is superscript. Includes bibliographical references (p. 360-379).