Microbiology Commons^™

Endogenous Glucocorticoid Signaling Is Required For Normal Macrophage Response To H. Pylori Infection, Stuti Khadka

Graduate Theses, Dissertations, and Problem Reports

Gastric cancer is the fifth leading cause of cancer-related deaths worldwide, affecting millions of people. H. pylori is the strongest risk factor for gastric cancer, with about 90% of the cases strongly associated with H. pylori infection. Half of the world's population is infected with this bacterium. However, only a small subset of the infected population (1-3 %) go on to develop gastric cancer. Diagnosis of the disease at an early stage is the biggest challenge because of the widespread prevalence of H. pylori infection and a long asymptomatic phase before the advanced stages. Patients are left with limited treatment …

Campylobacter Jejuni Capsular Heptose: Moderation Of Host Macrophages And Substrate Channeling During Synthesis, Matthew Myles

Electronic Thesis and Dissertation Repository

With the majority of Canadian Campylobacter jejuni infections resulting from contaminated poultry, I investigated how the strain NCTC 11168 capsular heptose modulates host macrophage activation, and bacterial clearance. Activation was assessed by ELISAs, Griess assays, qRT-PCR, and cytokine multiplex, while looking at adhesion to, uptake by, and survival within host macrophages. The heptose was immunosuppressive in chicken, but not human, macrophages and did not significantly impact clearance by tested host macrophages. It is also likely that heptose biosynthesis enzymes engage in substrate channelling, as previous data indicates that these enzymes have a means to limit degradation of unstable intermediates within …

Il-10 And Tgf-Beta Increase Connexin-43 Expression And Membrane Potential Of Hl-1 Cardiomyocytes Coupled With Raw 264.7 Macrophages, Cora B. Cox

Browse all Theses and Dissertations

Cardiomyocytes and macrophages have been found to interact via connexin-43 hemichannels. The role of connexin-43, however, is not fully understood. This study shows that these interactions aid in increasing the membrane potential of cardiomyocytes allowing contraction of the cells. HL-1 cardiomyocytes and RAW 264.7 macrophages in coculture increased expression of connexin-43 compared to cardiomyocytes alone. Co-cultures also increased the fluorescence of Di-8-ANEPPS potentiometric dye indicating an increase in cardiomyocyte membrane potential. Treatment with IL-10 and TGF-beta further increased connexin-43 expression and membrane potential. Treatment with SOCS3 inhibited the effects of TGF-beta and IL-10 while having no effect on its own. …

Investigating The Roles Of Lipids In Staphylococcus Aureus Infection, Xi Chen

Dissertations

The Gram-positive bacterium Staphylococcus aureus is a major threat to public health and causes a multitude of infections, ranging from mild skin and soft infection, to more severe diseases including sepsis, osteomyelitis and infective endocarditis. As a successful pathogen, S. aureus employs various mechanisms to invade host tissues, evade immune responses, and survive in the host environment. One critical adaptive trait of S. aureus that promotes virulence and survival is the ability to maintain membrane homeostasis via flexible modifications to its lipid composition in response to the surrounding lipid environment. Phospholipids are the major component of the bacterial membrane and …

Investigation Of The Growth And Survival Of Staphylococcus Aureus In Cftr-Deficient Macrophages, Bita Azad

Electronic Thesis and Dissertation Repository

Staphylococcus aureus and its small colony variants (SCVs) are commonly isolated from the lungs of cystic fibrosis (CF) patients. Although studies have suggested that cystic fibrosis transmembrane regulator (CFTR)-deficient macrophages are diminished in their ability to kill intracellular pathogens, whether this is true for CFTR-deficient macrophages infected with S. aureus or its SCVs is unknown. I employed gentamicin protection and eFluorÔ-670-based proliferation assays to assess the intracellular replication of S. aureus in CFTR inhibitor treated THP-1 and primary human macrophages, and in primary macrophages derived from CF patient blood. My work shows that the susceptibility of CFTR-deficient macrophages to the …

Modulation Of Host Innate Immune Cells By Yersinia Pestis To Create A Permissive Environment For Replication., Amanda Rose Pulsifer

Electronic Theses and Dissertations

Yersinia pestis has gained widespread infamy due to the historic outbreak during the middle ages, referred to as The Black Death. Infection with Y. pestis typically begins with deposition of Y. pestis into the dermis (bubonic plague) or respiratory tract (pneumonic plague). Tissue resident macrophages are the first innate immune cell encountered by Y. pestis. Macrophages are likely a way for Y. pestis to avoid neutrophils early in infection when the neutrophil neutralizing Type Three Secretion System is not expressed. This work focuses on which Rab host proteins are manipulated by Y. pestis, and how neutrophils are forced to …

Perivascular Macrophages In The Neonatal Macaque Brain Undergo Massive Necroptosis After Simian Immunodeficiency Virus Infection, Diana G. Bohannon, Yueying Wang, Colin H. Reinhart, Julian B. Hattler, Jiangtao Luo, Hamid R. Okhravi, Jianshui Zhang, Qingsheng Li, Marcelo J. Kuroda, Woong-Ki Kim

Nebraska Center for Virology: Faculty Publications

We previously showed that rhesus macaques neonatally infected with simian immunodeficiency virus (SIV) do not develop SIV encephalitis (SIVE) and maintain low brain viral loads despite having similar plasma viral loads compared to SIV-infected adults. We hypothesize that differences in myeloid cell populations that are the known target of SIV and HIV in the brain contribute to the lack of neonatal susceptibility to lentivirus-induced encephalitis. Using immunohistochemistry and immunofluorescence microscopy, we examined the frontal cortices from uninfected and SIV-infected infant and adult macaques (n = 8/ea) as well as adults with SIVE (n = 4) to determine differences in myeloid …

Crispr/Cas9 Whole Genome Screens Reveal Novel Regulators Of Endocytic Processes In Macrophages, Jared Wollman

Electronic Theses and Dissertations

Macrophages maintain tissue homeostasis by identifying and eliminating threats within their tissue microenvironment. Pattern recognition receptors allow macrophages to recognize and internalize specific ligands while macropinocytosis allows the internalization of all extracellular solutes from their environment. Without pattern recognition receptors, pathogens may grow unchecked if they cannot be detected, and without macropinocytosis, macrophages struggle to detect and move around their environment. This thesis presents the results of CRISPR/Cas9 whole-genome screens used to identify the regulators of both endocytosis (Chapter 2) and macropinocytosis (Chapter 3). In Chapter 2, we report genes regulating dextran uptake in primary murine macrophages and reveal Mrc1-mediated …

Synthesis And Characterization Of A Long-Acting Emtricitabine Prodrug Nanoformulation, Ibrahim M. Ibrahim

Theses & Dissertations

The introduction of highly active antiretroviral therapy led to a paradigm shift in the management of HIV/AIDS changing a disease considered “a death sentence” to “a manageable chronic disease”. Nevertheless, challenges exist for successful treatment of HIV, including patient adherence to the complex daily regimens and the inability of current formulations to target viral sanctuaries. Introduction of nanoformulated antiretroviral therapy (ART) is a promising alternative to tackle these challenges. Our laboratory has been focusing on developing long-acting (LA) nanoformulated antiretrovirals and has succeeded in developing LA integrase inhibitors. However, challenges for this approach extend to a range of short-acting hydrophilic …

Staphylococcus Aureus Evasion Of The Innate Immune System, James Paul Grayczyk

Dissertations

Upon entry into the host, pathogens must overcome innate immunity in order to cause disease. The innate immune system represents a fast-acting initial line of defense to prevent infection. In order to withstand innate defenses, bacterial pathogens like the Gram-positive bacterium Staphylococcus aureus, produce a wide array of virulence factors that can inhibit innate immune cell recruitment and antimicrobial activity, or directly target and kill phagocytic leukocytes thereby facilitating pathogenesis. Infection with S. aureus can cause disease in virtually any tissue site and is a significant burden to human health. In this dissertation, we sought to understand how S. aureus …

The Response Of M0, M1, And M2 Raw246.7 Macrophage Cell Line To Hsv-1 Infection In Vitro, Amani Mohammed Alhazmi

Browse all Theses and Dissertations

Herpes Simplex Virus Type 1 (HSV-1) infection occurs through the epithelial cells of the skin or mucous membranes. The beginning of the primary infection is rapid and is characterized by pain in the mouth, salivation, and submandibular lymphadenitis. The infected mucosa produces numerous, small and red lesions known as cold sores, however, many cases are asymptomatic. After the primary infection HSV-1 moves through the nerve to stay in trigeminal ganglia and to cause a recurrent infection from time to time. In the early hours of the HSV-1 infection, the cytokines produced by infected cells are critical in the stimulation of …

The Effects Of Socs1 And Socs3 Peptide Mimetics On Macrophage Phagocytosis Of Malignant Cells, Tahirah M. Madkhali

Browse all Theses and Dissertations

Macrophages are essential phagocytic cells involved in both innate and adaptive immune systems and play vital roles in the host defense and inflammation. Macrophages have a remarkably high capacity to clear unnecessary cellular materials in interstitial environment through a process called “phagocytosis”, which is affected by many factors including suppressors of cytokine signaling (SOCS). SOCSs are a group of intracellular proteins that downregulate the cytokine signals involved in various JAK/STAT pathways through a negative feedback loop. This study focuses on investigating the effects of SOCS1 and SOCS3 on the phagocytic ability of RAW 264.7 macrophages polarized into M2a with IL-4/IL-13 …

The Surreptitious Survival Of The Emerging Pathogen Staphylococcus Lugdunensis In Macrophages Enhances S. Aureus Infection, David Watson

Electronic Thesis and Dissertation Repository

Staphylococcus lugdunensis is an opportunistic pathogen that can cause invasive infections suggesting an ability to circumvent host immunity. S. lugdunensis was shown to resist killing and persist within macrophages and acetylation of its peptidoglycan is important for this survival. This was consistent in vivo, as S. lugdunensis resides inside Kupffer cells for at least 16 hours post-infection in mice. Despite its capability for survival, S. lugdunensis is unable to replicate within phagolysosomes. Inhibiting phagolysosomal effectors allows S. lugdunensis to initiate replication, after which the bacteria escape phagosomal containment. Moreover, intracellular S. lugdunensis augments the growth S. aureus during co-infection. Eight …

Iron And Copper Homeostasis In Staphylococcus Aureus, Holly A. Laakso

Electronic Thesis and Dissertation Repository

All microorganisms require transition metals for key metabolic processes, thus during infection microbial access to essential metals is tightly regulated by the host in a process termed nutritional immunity. Iron acquisition is critical to the pathogenesis of the formidable human pathogen, Staphylococcus aureus, which utilizes heme-uptake systems and two high-affinity iron-scavenging siderophores, staphyloferrin A (SA) and staphyloferrin B (SB) for iron acquisition. In this study, I identify sbnI as encoding a transcription factor required for expression of genes in the sbn operon, the biosynthetic operon for SB synthesis. I also show that SbnI is a novel hemoprotein, where binding …

Hsv-1 Replication In Different Raw 264.7 And J774.1 Macrophage Phenotypes And Macrophage Viability Following Hsv-1 Infection, Yousef Nifaj Alanazi

Browse all Theses and Dissertations

HSV-1 is a ubiquitous virus capable of causing lifelong latent infection. The virus contains a large double strand DNA genome covered by an icosahedral capsid. HSV-1 is a cytolytic virus which can cause a lethal infection. The virus possesses critical protein ICP0 which is capable of interfering with host cell signaling and eventually prevent cell apoptosis. Innate immunity plays a crucial role in defense against HSV-1 infection and macrophage plays a significant role in the innate immune system. Macrophage cells can alter their behavior depending upon certain stimuli and tissue environments. Naive macrophage (M0) cells can be polarized to a …

Virus Production And Cell Viability Of Hsv-1-Infected Murine Keratinocytes (Hel-30) Co-Cultured With Murine Macrophages (Raw 264.7), Barry Graffagna

Browse all Theses and Dissertations

Keratinocytes are the most abundant type of cell in the outer layer of skin, the epidermis, and provide barrier against pathogens from invading. However, Herpes Simplex Virus Type 1 (HSV-1) targets these keratinocytes for infection, and later infects neurons to establish lifelong latency. The keratinocytes stimulate the innate immune system to engage and to destroy the virus. Among the cells of the innate immune system to respond to the viral invasion is the macrophage. In this study, RAW 264.7 macrophage and HEL-30 keratinocyte monolayers were challenged in vitro with HSV-1 at a multiplicity of infection (MOI) of 0.1 to investigate …

Antibody Dependent Enhancement Of Visceral Leishmaniasis, Alan K. Mcnolty

All Master's Theses

Leishmaniasis is a parasitic disease caused by protozoans of the genus Leishmania. This vector-born disease, transmitted by biting phlebotomine sandflies, typically manifests in one of three ways. The cutaneous form of the disease is characterized by localized lesions of the skin and is by far the most common manifestation. The visceral form of the disease is caused by parasitic infiltration of internal organs, particularly the spleen, liver, and bone marrow. The mucocutaneous form is caused by parasitic infection of the mucosa in the nose or mouth. While cutaneous leishmaniasis (CL) is often self-healing, visceral leishmaniasis (VL) is fatal if …

Effects Of Socs1 And Socs3 Peptide Mimetics On Macrophage Phagocytosis Of Malignant Cells, Colt Dylan Capan

Browse all Theses and Dissertations

Macrophages play a key role in both the innate and adaptive immune system responses to foreign materials. Suppressors of cytokine signaling (SOCS) proteins are known as regulators of the immune response through various JAK/STAT pathways. This study examined the roles of SOCS1 and SOCS3 peptide mimetics on the phagocytosis of fluorescently labeled malignant target cell by RAW264.7 murine macrophages. The malignant cells used were Neuro-2a cells, a murine neuroblastoma cell line. A prominent “eat me” signal found in neuroblastoma cells is calreticulin (CRT), which permits macrophages to recognize and then phagocytize the malignant cells. When M1 (pro-inflammatory) polarized macrophages were …

Effects Of Socs1 And Socs3 Peptide Mimetics On Macrophage Phagocytosis Of Malignant Cells, Colt Dylan Capan

Browse all Theses and Dissertations

Macrophages play a key role in both the innate and adaptive immune system responses to foreign materials. Suppressors of cytokine signaling (SOCS) proteins are known as regulators of the immune response through various JAK/STAT pathways. This study examined the roles of SOCS1 and SOCS3 peptide mimetics on the phagocytosis of fluorescently labeled malignant target cell by RAW264.7 murine macrophages. The malignant cells used were Neuro-2a cells, a murine neuroblastoma cell line. A prominent "eat me" signal found in neuroblastoma cells is calreticulin (CRT), which permits macrophages to recognize and then phagocytize the malignant cells. When M1 (pro-inflammatory) polarized macrophages were …

Role Of Atg16l1 In Uropathogenic E. Coli Pathogenesis, Jane Symington

Arts & Sciences Electronic Theses and Dissertations

Urinary tract infections (UTIs) are among the most common infectious diseases and are primarily caused by uropathogenic E. coli (UPEC). Given the greater incidence of antibiotic resistance among UPEC isolates, it is vital to determine factors and pathways important for an effective host response to UPEC in order to improve therapeutic options for combating UTIs. Autophagy is a cellular degradation pathway that plays important roles in pathogen control and modulation of innate immunity. One essential autophagy protein, ATG16L1, has been further implicated in controlling inflammation due to a common variant of ATG16L1 being associated with increased risk of Crohns disease, …

Identification Of Host Factors Required For Yersinia Pestis Macrophage Intracellular Survival And Their Impact On Vacuole Maturation, Acidification And Trafficking., Michael Graylin Connor

Electronic Theses and Dissertations

Y. pestis is a facultative intracellular pathogen and the causative agent of plague. This bacterium, while most noted or the Black Death during the European 14^th century, is not a historic pathogen but a re-emerging pandemic with both domestic and global impact. Y. pestis is capable of colonizing the macrophage, and actively subverts phagolysosome maturation to establish a replicative niche known as the Yersinia containing vacuole (YCV). The exploited host factors required to support the YCV are unknown. Here we identified a comprehensive list of host factors required for Y. pestis survival through a genome-wide RNAi high-throughput screen. We …

Pharmacologic Immunomodulation Of Macrophage Activation By Caffeine, Ryan Perry Steck

Theses and Dissertations

Caffeine is one of the most widely used neurostimulants in the world and there is considerable debate on its effect in immune cells. One of its main targets is proposed to be adenosine receptors which mediate an anti-inflammatory switch in activated immune cells while another target is phosphodiesterase where it acts as an inhibitor. In macrophages, caffeine has been shown to cause both pro-inflammatory (M1) and anti-inflammatory (M2) phenotypes. If the primary effect of caffeine on macrophages were to antagonize adenosine receptors we would expect cells exposed to caffeine to have a prolonged M1 response. However, we show that caffeine …

Role Of Viral And Host Factors In Influenza Virus Mediated Inhibition Of Interleukin-23, Ashish Tiwari

Theses and Dissertations--Veterinary Science

Influenza virus is one of the major respiratory pathogens of humans as well as animals, including equines. There is an increasing evidence that bacterial infections are the most common cause of the death during influenza. In horses also, secondary bacterial pneumonia can lead to death, and surviving horses may take up to six months for the complete recovery resulting in heavy economic loss to the equine industry. Interleukin (IL)-23 mediated innate immune response has been shown to protect the host from various respiratory bacterial infections. However, studies to investigate the role of host and viral factors in the regulation of …

Regulation Of Rab5 Gtpase Activity During Pseudomonas Aeruginosa-Macrophage Interaction, Sushmita Mustafi

FIU Electronic Theses and Dissertations

Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen. Several antibiotic resistant strains of P. aeruginosa are commonly found as secondary infection in immune-compromised patients leaving significant mortality and healthcare cost. Pseudomonas aeruginosa successfully avoids the process of phagocytosis, the first line of host defense, by secreting several toxic effectors. Effectors produced from P. aeruginosa Type III secretion system are critical molecules required to disrupt mammalian cell signaling and holds particular interest to the scientists studying host-pathogen interaction. Exoenzyme S (ExoS) is a bi-functional Type III effector that ADP-ribosylates several intracellular Ras (Rat sarcoma) and Rab (Response to abscisic acid) small GTPases …

Effects Of Chemical Stimulation And Tumor Co-Incubation On Macrophage Activation And Aggressiveness, Measured Through Phagocytosis And Respiratory Burst, Bo Marcus Gustafsson

Theses and Dissertations

Macrophages are a cornerstone in innate immunity, especially important in detecting and killing invading microorganisms. In tumor biology, the macrophages can contribute both to anti-tumor activity and tumor promotion depending on individual tumor microenvironment and therefore have a large impact on both tumor progression and prognosis. Two of the most important functions of macrophages are the ability to phagocytose microorganisms and then kill them through the respiratory burst. Phagocytosis activates the respiratory burst, but the more subtle interactions between these processes are less known. Since phagocytosis and reactive oxygen species production are two attributes that change between the classically and …

The Construction Of A Plasmid For Detecting The Pathway Of Arginine Metabolism In Human Macrophages: A Real-Time Assessment Of Macrophage Polarity, Benjamin A. Holmes

Browse all Theses and Dissertations

Macrophages are "first responders", innate immune system cells which quickly arrive to a site of infection and injury, consuming cell debris and foreign matter and recruiting other immune system cells to the area. While historically they have been thought to react uniformly to all challenges, the discovery of toll-like receptors has shown that macrophages actually work closely with the adaptive immune system in fine-tuning the immune response. Furthermore, it has recently been discovered that macrophages can become polarized to one of two subtypes-M1 or M2.

M1 macrophages are efficient producers of reactive oxygen species, nitrogen intermediates, and inflammatory cytokines. They …

The Intracellular Behaviour Of Burkholderia Cenocepacia In Murine Macrophages, Jennifer S. Tolman

Electronic Thesis and Dissertation Repository

Burkholderia cenocepacia is an opportunistic pathogen causing life-threatening infections in cystic fibrosis and other immunocompromised patients. The bacterium survives within macrophages by interfering with typical endocytic trafficking, resulting in delayed maturation of a B. cenocepacia-containing phagosome. We hypothesize that B. cenocepacia alters gene expression after internalization by macrophages, inducing genes involved in intracellular survival and host adaptation. Furthermore, we hypothesize that specialized bacterial secretion systems are involved in the interactions between intracellular bacteria and macrophages. In this work, we characterize later-stage infection of macrophages by B. cenocepacia, showing replication within an acidified endosomal compartment suggestive of a phagolysosome. …

Assessing The Relationship Of Monocytes With Primary And Secondary Dengue Infection Among Hospitalized Dengue Patients In Malaysia, 2010: A Cross-Sectional Study, Benjamin Glenn Klekamp

USF Tampa Graduate Theses and Dissertations

Dengue, a group of four similar viruses transmitted through the bite of a mosquito, is estimated to infect upwards of 100 million annually in over 100 nations throughout the global equatorial belt. Distribution of global dengue is highly skewed as Southeast Asian and Western Pacific regions endure 75% of the global dengue burden. Similar to other regional countries, Malaysia has been rapidly urbanizing, which has supported a hyperendemic dengue state.

The biological pathway by which dengue infection causes a wide range of clinical manifestations, spanning asymptomatic to life-threatening severe complications, is not comprehensively understood. Historically, severe dengue complications have primarily …