Background and Aim: Bacterial infections are a well described complication of cirrhosis and occur in 37% of hospitalized patients. Culture positive infections in addition to the presence of bacterial products and DNA lead to loss of liver function and decompensation in cirrhosis. The mechanisms and molecular pathways associated with Bacterial Translocation (BT) are unknown. The aims of this study were to determine: i. macrophage phenotype and molecular pathways associated with bacterial translocation ii. if intestinal macrophages in liver cirrhosis are capable of modulating intestinal permeability.iii. structural integrity of the epithelial barrier. Methods: Duodenal biopsies and serum samples were collected from 29 patients with decompensated cirrhosis, 15 patients with compensated and 19 controls. Duodenal macrophages were characterized by means of flow cytometry and IHC. Gene expression analysis was performed to determine molecular pathways involved in BT. Inflammatory cytokine determination was done in serum and culture supernatant by means of customized cytometric bead arrays. Results: Patients with decompensated cirrhosis demonstrated: increased frequency of CD33+/CD14+/TREM-1+ and iNOS+ macrophages in their duodenum, elevated mRNA levels of nitric oxide synthase 2 (NOS2), chemokine ligand 2 (CCL2), chemokine ligand 13 (CCL13) and interleukin 8 (IL8) and increased serum levels of interleukin 6 (IL6), IL8 and lipopolysaccharides (LPS). Additionally, patients with decompensated cirrhosis showed an increase in NO, IL6, IL8 and CCL2 levels in culture supernatant after short term duodenal biopsy culture. Although the epithelial barrier on EM seemed intact, significantly increased expression of the “pore” forming tight junction claudin 2 was observed. Conclusion: This study showed the presence of activated CD14+Trem- 1+iNOS+ intestinal macrophages and increased levels of NO, IL-6 and claudin-2 levels in the duodenum of patients with decompensated liver cirrhosis, suggesting that these factors enhance intestinal permeability to bacterial products. / Afrikaans: Inleiding: Bakteriele infeksie is ‘n beskryfde komplikasie van lewersirrose wat in 37% van gehospitaliseerde pasiente voorkom. Kultuur positiewe infeksies asook die teenwoordigheid van bakteriele produkte en DNA lei tot verlies van lewerfunksie en dekompensasie. Die molekulere meganismes wat verband hou met bakteriele translokasie is nog onbekend. Die doel van hierdie studie was om: i. Makrofaag fenotipe en molekulere meganismes geassosieerd met bakteriele translokasie te beskryf, ii. te bepaal of intestinale makrofage dermdeurlaatbaarheid beinvloed, asook iii. om die struktruele integriteit van die dermwand te bepaal. Methods: Serum en dunderm biopsies was verkry van 29 pasiente met gedekompenseerde lewer sirrose, 15 pasiente met gekompenseerde sirrose en 19 kontroles. Dunderm makrofage was gekarakteriseer met behulp van vloeisitometrie en immunohistochemie. Molekulere meganisms belangrik tydens bakteriele translokasie was bepaal met behulp van geneekspressie. Serum en selkultuur supernatant sitokien bepalings was met Bioplex assays gedoen. Resultate: Pasiente met gedekompenseerde sirrose demonstreer: ‘n verhoogde frekwensie van CD33+/CD14+/TREM-1+ en iNOS+ makrofage in hul dunderm, verhoogde mRNA vlakke van NOS2, CCL2, CCL13 en IL8 asook verhoogde serum vlakke van IL6, IL8, LPS. Addisioneel het pasiente met gedekompenseerde sirrose vehoogde supernatant vlakke van NO, IL6, IL8 and CCL2 na kort termyn dunderm biopsie kulture. Alhoewel elekronmikroskopie gewys het dat die dundermwand intak is, was daar statisties-beduidend verhoogde ekspressie van die “porie” vormende vasteaansluitings- proteien, claudin 2 sigbaar. Gevolgtrekking: Gesamentlik het die studie gewys dat geaktiveerde CD14+/Trem-1+/iNOS+ intestinale makrofage asook verhoogde vlakke van NO, IL-6 en claudin-2 teenwoordig is in die dunderm van pasiente met gedekompenseerde sirrose. Dit dui daarop dat diè faktore derm deurlaatbaarheid vir bakteriele produkte kan verhoog. / Dissertation (MSc)--University of Pretoria, 2011. / Immunology / MSc / Unrestricted

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.

Chikungunya virus (CHIKV) is classified as an alphavirus in the Togaviridae family. This virus is known to rely on Aedes arthropod vectors for its dissemination. Human infection is characterized by rash, high fever, and severe chronic polyarthritis that can last for years. Recently, efforts in developing animal models have been made in an attempt to better understand CHIKV pathogenesis. CHIKV infection starts with a 7 to 10 day long febrile acute phase, in which most of the symptoms occur (rash, fever, and incapacitating pain in joints and muscle). Once the immune system clears most of the viral infection, a chronic phase starts in as many as 70% of the infected patients. Long term virus-related polyarthralgia is the hallmark of the CHIKV chronic phase. It is believed that CHIKV-infected macrophages infiltrate the joints during the acute phase, and CHIKV infects joint tissue and persists in it. Research into the effects of CHIKV infection in human and murine macrophages revealed that CHIKV-infected human macrophages produce high amounts of virions as well as induce the production of pro-inflammatory cytokines and monocyte recruiting chemokines. This contrasts with murine macrophage infection where low quantities of the virus were detected as well as lower production of pro-inflammatory cytokines. This may contribute to the lack of polyarthritis in murine animal models. Current literature suggests that CHIKV’s viral proteins bind and interact with human host cell machinery promoting viral replication more efficiently in humans than in mice. CHIKV-related neuropathology is not the most common outcome of the disease. However, recent outbreaks suggest that this pathology is becoming more prevalent, affecting as many as 30% of confirmed patients. The role of adaptive and innate immunity in CHIKV disease amelioration has been extensively, yet separately, explored. A RAG2-/-γc-/- Balb/c mouse model was used to study the role of these immune pathways and their associated immune cells in CHIKV infection. The mice in this study developed local arthritis at the site of inoculation as well as showed signs of viral invasion in the brain. This study added to the hypothesis that both innate and adaptive immune responses are necessary to ameliorate the disease and that the lack of adequately matured lymphocytes and STAT6-activation deficient macrophages may result in more severe pathologies.

付記する学位プログラム名: 充実した健康長寿社会を築く総合医療開発リーダー育成プログラム / 京都大学 / 0048 / 新制・課程博士 / 博士(薬科学) / 甲第22396号 / 薬科博第118号 / 新制||薬科||13(附属図書館) / 京都大学大学院薬学研究科薬科学専攻 / (主査)教授 髙倉 喜信, 教授 山下 富義, 教授 小野 正博 / 学位規則第4条第1項該当 / Doctor of Pharmaceutical Sciences / Kyoto University / DFAM

In an effort to elucidate the mechanism by which indomethacin (IN) lessens the stimulatory effect of estradiol (E2) on rabbit splenic red pulp macrophages (RPMs), 39 female New Zealand White rabbits were divided into 10 groups: ovariectomized (OVX) and OVX/ IN at 0.1 and 5.0 mg/kg body weight (bw)/day; sham OVX (SOVX) and SOVX/IN at 0.1 and 5.0 mg/kg bw/day; OVX/25 mg E2 and OVX/25 mg E2/IN at 0.1 and 5.0 mg/kg bw/day; and intact control. Changes in RPM population in response to treatment were measured using a 0-4 histologic grade. Estradiol treatment resulted in increased RPM grade when compared to the OVX groups. Indomethacin addition lowered mean RPM grade in the SOVX/IN 5.0 group when compared to its E2 control group. Indomethacin administration had no significant effect on levels of prostaglandin E 2 in spleen, urine, or blood. Hematocrits were reduced in both OVX and OVX/E2 groups; this decrease was exacerbated by the high IN dose. In summary, the results from this study suggest that the effect of IN on E2-induced RPM activation may be mediated through a nonprostaglandin pathway. The observed hematocrit changes are possibly the result of direct action of IN and E2 on erythrocytes, resulting in their accelerated clearance from the circulation by splenic RPM.

The macrophage scavenger receptor class A (SR-A) participates in the innate immune and inflammatory responses. This study examined the role of macrophage SR-A in myocardial ischemia/reperfusion (I/R) injury and hypoxia/reoxygenation (H/R)-induced cell damage. SR-A-/- and WT mice were subjected to ischemia (45min) followed by reperfusion for up to 7days. SR-A-/- mice showed smaller myocardial infarct size and better cardiac function than did WT I/R mice. SR-A deficiency attenuated I/R-induced myocardial apoptosis by preventing p53-mediated Bak-1 apoptotic signaling. The levels of microRNA-125b in SR-A-/- heart were significantly greater than in WT myocardium. SR-A is predominantly expressed on macrophages. To investigate the role of SR-A macrophages in H/R-induced injury, we isolated peritoneal macrophages from SR-A deficient (SR-A-/-) and wild type (WT) mice. Macrophages were subjected to hypoxia followed by reoxygenation. H/R markedly increased NF-κB binding activity as well as KC and MCP-1 production in WT macrophages but not in SR-A-/- macrophages. H/R induced caspase-3/7 and -8 activities and cell death in WT macrophages, but not in SR-A-/- macrophages. The levels of miR-125b in SR-A-/- macrophages were significantly higher than in WT macrophages. Transfection of WT macrophages with miR-125b mimics attenuated H/R-induced caspase-3/7 and -8 activities and H/R-decreased viability, and prevented H/R-increased p-53, Bak-1 and Bax expression. The data suggest that SR-A deficiency attenuates myocardial I/R injury by targeting p53-mediated apoptotic signaling. SR-A-/- macrophages contain high levels of miR-125b which may play a role in the protective effect of SR-A deficiency on myocardial I/R injury and H/R-induced cell damage.

The macrophage scavenger receptor class A (SR-A) participates in the innate immune and inflammatory responses. This study examined the role of macrophage SR-A in myocardial ischemia/reperfusion (I/R) injury and hypoxia/reoxygenation (H/R)-induced cell damage. SR-A-/- and WT mice were subjected to ischemia (45min) followed by reperfusion for up to 7days. SR-A-/- mice showed smaller myocardial infarct size and better cardiac function than did WT I/R mice. SR-A deficiency attenuated I/R-induced myocardial apoptosis by preventing p53-mediated Bak-1 apoptotic signaling. The levels of microRNA-125b in SR-A-/- heart were significantly greater than in WT myocardium. SR-A is predominantly expressed on macrophages. To investigate the role of SR-A macrophages in H/R-induced injury, we isolated peritoneal macrophages from SR-A deficient (SR-A-/-) and wild type (WT) mice. Macrophages were subjected to hypoxia followed by reoxygenation. H/R markedly increased NF-κB binding activity as well as KC and MCP-1 production in WT macrophages but not in SR-A-/- macrophages. H/R induced caspase-3/7 and -8 activities and cell death in WT macrophages, but not in SR-A-/- macrophages. The levels of miR-125b in SR-A-/- macrophages were significantly higher than in WT macrophages. Transfection of WT macrophages with miR-125b mimics attenuated H/R-induced caspase-3/7 and -8 activities and H/R-decreased viability, and prevented H/R-increased p-53, Bak-1 and Bax expression. The data suggest that SR-A deficiency attenuates myocardial I/R injury by targeting p53-mediated apoptotic signaling. SR-A-/- macrophages contain high levels of miR-125b which may play a role in the protective effect of SR-A deficiency on myocardial I/R injury and H/R-induced cell damage.

CD36 is a pleiotropic receptor involved in several pathophysiological conditions, including cerebral ischemia, neurovascular dysfunction and atherosclerosis, and recent reports implicate its involvement in the endoplasmic reticulum stress response (ERSR). We hypothesized that CD36 signaling contributes to the inflammation and microvascular dysfunction following spinal cord injury. Following contusive injury, CD36-/- mice demonstrated improved hindlimb functional recovery and greater white matter sparing than CD36+/+ mice. CD36-/- mice exhibited a reduced macrophage, but not neutrophil, infiltration into the injury epicenter. Fewer infiltrating macrophages were either apoptotic or positive for the ERSR marker, phospho-ATF4. CD36-/- mice also exhibited significant improvements in injury heterodomain vascularity and function. These microvessels accumulated less of the oxidized lipid product 4-hydroxy-trans-2-nonenal (4HNE) and exhibited a reduced ERSR, as detected by vascular phospho-ATF4, CHOP and CHAC-1 expression. In cultured primary endothelial cells, deletion of CD36 diminished 4HNE-induced phospho-ATF4 and CHOP expression. A reduction in phospho-eIF2α and subsequent increase in KDEL-positive, ER-localized proteins suggest that 4HNE-CD36 signaling facilitates the detection of misfolded proteins upstream of eIF2α phosphorylation, ultimately leading to CHOP-induced apoptosis. We conclude that CD36 deletion modestly, but significantly, improves functional recovery from spinal cord injury by enhancing vascular function and reducing macrophage infiltration. These phenotypes may, in part, stem from reduced ER stress-induced cell death within endothelial and macrophage cells following injury.

Candida albicans is an increasingly important pulmonary fungal pathogen. Resident alveolar macrophages are important in host defense against opportunistic fungal infections. Activation of Group IVA cytosolic phospholipase A2α (cPLA2α) in macrophages initiates arachidonic acid (AA) release for production of eicosanoids, which regulate inflammation and immune responses. We investigated the ability of C. albicans to activate cPLA2α in unprimed alveolar macrophages and after priming with granulocyte macrophage colony-stimulating factor (GM-CSF), which regulates alveolar macrophage maturation. AA was released within minutes by GM-CSF-primed but not unprimed alveolar macrophages in response to C. albicans, and was blocked by soluble glucan phosphate (S-GP). The expression of the β-glucan receptor dectin-1 was increased in GM-CSF-primed macrophages, and AA release from GM-CSF-primed dectin-1-/- alveolar macrophages was reduced to basal levels. The enhanced activation of extracellular signal-regulated kinases and phosphorylation of cPLA2α on Ser-505 that occurred in GM-CSF-primed macrophages were reduced by MEK1 and Syk inhibitors, which also suppressed AA release. At later times after C. albicans infection (6 h), unprimed and GM-CSF-primed macrophages released similar levels of AA. The expression of cyclooxygenase 2 and prostanoid production at 6 hours was higher in GM-CSF-primed macrophages, but the responses were not dependent on dectin-1. However, dectin-1 contributed to the C. albicans-stimulated increase in TNF-α production that occurred in GM-CSF-primed macrophages. The results demonstrate that dectin-1 mediates the acute activation of cPLA 2α in GM-CSF-primed alveolar macrophages, but not in the more delayed phase of AA release and GM-CSF-dependent prostanoid production.

Breast cancer is the second most common malignancy in the world, accounting for over 1.7 million new diagnoses and an estimated 500,000 deaths per year (1). Overexpression of the receptor tyrosine kinase ErbB2, also known as Her2 or Neu, occurs in over 30% of breast cancers and correlates with metastasis, poor prognosis, and decreased survival (1, 2). Although therapeutics targeting ErbB2 show clinical efficacy, many patients display no initial response or develop drug resistance over time (2). A deeper understanding of the molecular basis of ErbB2-driven tumorigenesis is thus required for the development of improved therapeutic strategies. In vitro experiments suggest that activation of the c-Jun NH2-terminal kinase (JNK) pathway, a mitogen-activated protein kinase pathway, promotes proliferation, cellular invasion, and stem cell expansion in ErbB2-driven breast cancer (3, 4). Furthermore, unpublished data from our lab using mammary epithelial cells expressing activated ErbB2 show that JNK is required for acinus formation in in vitro 3D cultures. In contrast to these studies showing a tumorigenic role for the JNK pathway, other data from our lab show that JNK loss results in accelerated breast tumor growth, suggesting a tumor suppressive role (5, 6). However, these studies were performed in p53 knockout mice with or without a Kras mutation, where the latter required extensive aging and genomic instability to occur before differences in tumor growth were observable. To date, limited in vivo studies exist to confirm the role of JNK in more biologically relevant breast tumor models, such as in ErbB2-mediated cancer, which accounts for over 30% of all human breast cancers. In addition, the molecular mechanisms by which JNK signaling promotes ErbB2-driven tumorigenesis remains poorly understood. To address the discrepancy in JNK function between the in vitro ErbB2-driven breast cancer data and the in vivo p53 knockout tumor data, I began the development of an in vivo murine model to confirm the role of JNK in ErbB2-driven breast cancer. This mouse model will also allow us to test a potential mechanism by which JNK regulates tumorigenesis. Studies show that ErbB2-mediated secretion of the inflammatory cytokine IL6 promotes transformation and tumor growth by activation of the STAT3 transcription factor, triggering an IL6/STAT3 autocrine signaling loop (7,8). A major regulator of Il6 gene expression includes activator protein 1 (AP-1), a transcription factor composed of downstream JNK targets in the Jun protein family (9). In vitro experiments using ErbB2-overexpressing mammary epithelial cell lines show that chemical inhibition of JNK suppresses secreted IL6 protein levels, supporting a role for the JNK pathway in IL6 regulation (7). Thus, I hypothesize that JNK drives ErbB2-driven breast cancer by promoting IL6-mediated tumor progression. Addressing this will increase our understanding of the role of JNK in ErbB2-driven breast cancer and reveal a potentially new mechanism by which JNK functions in tumor progression. Additionally, I began the development of a mouse model that will allow us to investigate the role of JNK in macrophage polarization as an alternative mechanism by which JNK regulates ErbB2-driven breast cancer. In addition to promoting STAT3-dependent tumor growth, IL6 can indirectly drive tumorigenesis by promoting expression of the IL4 receptor in macrophages, triggering STAT6-mediated macrophage polarization towards the pro-tumorigenic M2 phenotype (10, 11). Unlike classically activated M1 macrophages, which promote inflammation and anti-tumor immunity, alternatively activated M2 macrophages function in immunosuppression and metastasis and correlate with advanced stages of breast cancer (12, 13). Further evidence supporting a role for the JNK pathway in macrophage polarization includes a recent study suggesting that JunB, a downstream JNK target and component of the AP-1 complex, plays a crucial role in the induction of M2 macrophage polarization in human alveolar macrophages (13). I hypothesize that activation of the JNK signaling pathway induces IL6-dependent macrophage polarization towards the pro-tumorigenic M2 phenotype. Addressing this hypothesis will determine for the first time whether JNK functions in regulating macrophage polarization within the tumor microenvironment, offering a potentially new mechanism by which JNK can promote ErbB2-driven breast cancer. Determining the role of JNK in ErbB2-mediated breast cancer will have direct therapeutic relevance, as targeting JNK has the potential to inhibit ErbB2-driven breast cancer and other IL6-mediated diseases. Investigating the underlying mechanisms by which JNK functions in ErbB2-positive breast cancer can also offer new molecular targets and further contribute to effective drug design.