Doctor of Philosophy, University of Akron, 2024, Polymer Science

As the demand for implantable medical devices by the healthcare industry continues to rise, the demand for novel commercial, medically relevant polymers grows as well. However, the time and resources required for the research and development of new polymer biomaterials remain a significant barrier for the entry of these materials into the medical device field. One of the critical issues that polymer biomaterials face is the lack of standardization of polymer characteristics, especially regarding biocompatibility and immunogenicity. These parameters require greater investigation as the foreign body response (FBR) is an inevitable immunological reaction to implanted medical devices and the biomaterials that comprise them. Broadly speaking, when biomaterials are first implanted, an inflammatory phase will begin which will be followed by a tissue proliferation and remodeling phase, which are greatly mediated by the host's population of macrophages and their associated cytokines. However, instead of the classic wound healing response to tissue damage, the presence of a foreign body provokes the FBR, wherein pro-inflammatory M1 macrophages stimulate chronic inflammation due to the inability to remove the implant. M1 macrophages are then stimulated with IL-4 and IL-13 cytokines, polarizing into pro-remodeling M2 macrophages, which continue to fuse into Foreign Body Giant Cells (FBGCs). This ultimately results in the fibrotic encapsulation and degradation of the medical implant, greatly reducing functionality and stability of the implant. While there exists research that focuses on biomaterials that modulates the FBR, especially that of hydrogels, there is no significant research available on the correlation between polymer characteristics such as chemical structure or physical properties and the macrophage polarization response and the subsequent FBR, obfuscating potential predictions of biomaterial immunogenicity. In this presentation, an attempt is made to show that an i (open full item for complete abstract)

Committee: Abraham Joy (Advisor); Mesfin Tsige (Committee Chair); Ge Zhang (Committee Member); Nita Sahai (Committee Member); Richard Londraville (Committee Member) Subjects: Biomedical Engineering

Doctor of Philosophy, Case Western Reserve University, 2023, Neurosciences

Neuroinflammation in the peripheral nervous system (PNS) is associated with the superior regenerative ability of the PNS compared to the CNS. A sciatic nerve lesion leads to the accumulation of macrophages at the lesion site, in the distal nerve (DN), and in the dorsal root ganglia (DRGs) containing the axotomized sensory neurons. These macrophages were thought to be primarily recruited from circulation by signaling through CCR2, the primary chemotactic receptor for circulating monocytes, using its ligand CCL2. Further, CCL2-CCR2 signaling was putatively required to induced a growth promoting macrophage phenotype. However, when we tested the role of CCL2 in vivo using both cell specific and global knockouts, we found no change in macrophage accumulation or regeneration. Two other CCR2 chemokines, CCL7 and CCL12, were upregulated by injury and compensated for the loss of CCL2 through CCR2 signaling. Using a Ccr2gfp knock-in/knock-out mouse we labeled recruited CCR2+ MDMs in a wildtype and CCR2 null background. Surprisingly, we found that DRG macrophage accumulation was normal in CCR2 null mice, and most were from a resident population. In both the lesion site and DN, most macrophages were MDMs, however resident macrophage proliferation and CCR2 independent recruitment mechanisms were activated to compensate for the loss of monocyte recruitment in CCR2 null mice. Importantly, despite being needed for monocyte recruitment, CCR2 signaling was not necessary for promoting axon growth. In CCR2 null mice, a peripheral conditioning lesion enhanced peripheral regeneration, maintained enhanced peripheral regeneration for 28 days, and enhanced regeneration in the dorsal root. Together demonstrating the CCL2-CCR2 signaling axis is not required for regeneration. We next devised experiments to test if macrophages in the DRG or nerve were stimulating regeneration. To test DRG macrophages, we lesioned two branches of the sciatic nerve which inflamed macrophages throughout the L3 an (open full item for complete abstract)

Committee: Jerry Silver (Committee Chair); Richard Zigmond (Advisor); Derek Abbott (Committee Member); Stanley Huang (Committee Member); Polyxeni Philippidou (Committee Member) Subjects: Immunology; Neurobiology; Neurosciences

Doctor of Philosophy, University of Akron, 0, Polymer Science

When the skin is compromised through injury, the onset of wound healing is initiated by signaling the surrounding cells to the wound site. Medical interventions may be required to prevent exacerbating wounds. One type of products are cellular matrices which is bioactive but expensive. The other types are synthetic acellular wound dressing which is inexpensive but bioinert. These two types of products are locating at two ends of the spectrum. As a result, there is an unmet need for bioactive but cost-effect materials for wound healing. In this dissertation, we aim at creating bio-active synthetic materials to from two directions, one is to enhance cell migration the other one is to modulate immune responses. First, we hypothesize that RGD-conjugated polymer could enhance the migration of fibroblast. The methodology of designing 3D-printed porous scaffolds post-functionalized with tripeptide RGD on the surface was established. In vitro, the migration rate of human dermal fibroblasts was increased from 12% to 35% as the RGD concentration increases. In vivo, slightly increased granulation tissue formation was observed for wounds treated with RGD functionalized scaffolds. In the second part, we hypothesized that polyesters with different functional groups could provide guidelines in designing synthetic skin grafts to prevent undesired immune responses. In vitro, pro-inflammatory cytokines (IL-1β) were measured by qPCR when seeding macrophages on polymer films and showed distinct immune profiles. This provided information on what functional groups may elicit early inflammation when implantation.

Committee: Abraham Joy (Advisor); James Eagan (Committee Chair); Christine McDonald (Committee Member); Nic Leipzig (Committee Member); Mesfin Tsige (Committee Member) Subjects: Biomedical Research; Polymer Chemistry

Doctor of Philosophy, Case Western Reserve University, 0, Pathology

Regulatory mechanisms of the immune system are essential for human health by maintaining homeostasis and preventing disease states such as excessive inflammation and autoimmunity. These vital functions are coordinated by a wide range of cells from multiple lineages that employ unique and inventive techniques to suppress immune overactivation. Here, we describe four instances of novel regulatory mechanisms, which all in their own capacities are rooted in host and microbial glycans. In one case, we report that FoxP3+ regulatory T cells (Tregs) respond to a dual cytokine signal discovered downstream of the microbial factor polysaccharide A (PSA) by eliciting robust immunosuppression through the production of IL-10 and the selective proliferation of IL-10-expressing Tregs. In another study, we find that the suppressive T cell phenotype downstream of PSA that has been the focus of decades of work is preceded by the ability of PSA to polarize an anti-inflammatory macrophage subtype. Another study examines the cellular compensation that occurs during genetic ablation of IL-10 in FoxP3+ Tregs, where type I regulatory T cells (Tr1) in the colon upregulate their production of IL-10 to prevent the spontaneous development of disease. In the final study, we describe a new role for CD22 on macrophages that transduces tissue sialylation status and drives the polarization of anti-inflammatory macrophages that are critical for shaping immune tone over time. Using the modalities described in this work, multiple mouse models of autoimmune and inflammatory diseases, including asthma, multiple sclerosis, and inflammatory bowel disease were therapeutically prevented or reversed, demonstrating the astounding power of glycans and the immune cells that respond to them.

Committee: Brian Cobb (Advisor); George Dubyak (Committee Chair); Clive Hamlin (Committee Member); Booki Min (Committee Member); Robert Fairchild (Committee Member) Subjects: Cellular Biology; Immunology; Pathology

Doctor of Philosophy, The Ohio State University, 2021, Microbiology

Listeria monocytogenes is a Gram-positive facultative intracellular pathogen and the causative agent of listeriosis. The elderly, immunocompromised individuals, pregnant women, and neonates are at a higher risk of severe infection. Pregnancy-associated listeriosis can lead to miscarriage, premature birth, and neonatal infection. The placenta acts as an exchange platform for nutrients, gases, and waste products for the fetus. It also has the crucial role of protecting the fetus against invading pathogens. Among numerous human pathogens, only a small number are capable of invading the placenta and infecting the fetus. L. monocytogenes is among those pathogens and is used as a model organism to study the mechanisms of fetal/placental infection by intracellular pathogens. It is thought that L. monocytogenes breaches the placental barrier by infecting either the extravillous trophoblasts or the multinucleated syncytiotrophoblast both of which are in direct contact with maternal blood at the maternal/placental interface. However, the fate of L. monocytogenes within the chorionic villi and how infection reaches the fetus are unsettled. Hofbauer cells (HBCs) are fetal macrophages that play homeostatic anti-inflammatory functions in healthy placentas. HBCs are located in chorionic villi between the two cell barriers that protect the fetus from infection: trophoblast cells at the maternal interface (in contact with maternal blood), and fetal endothelial cells at the fetal interface (in contact with fetal blood). As the only leukocytes residing in chorionic villi, HBCs form a critical immune barrier protecting the fetus from infection. Little is known about HBCs' antimicrobial responses to pathogens. Here, we present the first study of L. monocytogenes interactions with HBCs. Remarkably, despite their M2 anti-inflammatory phenotype at basal state, HBCs control non-pathogenic bacteria such as L. innocua and display low susceptibility to infection by L. monocytogenes. Ho (open full item for complete abstract)

Committee: Stephanie Seveau (Advisor); Amal Amer (Committee Member); Michael Ibba (Committee Member); Chad Rappleye (Committee Member) Subjects: Gynecology; Immunology; Microbiology; Obstetrics

Master of Science (MS), Wright State University, 2020, Pharmacology and Toxicology

Hypertension, also known as high blood pressure, is a long-term medical condition in which the blood pressure in the arteries is persistently elevated. It can lead to severe health complications and increase the risk of heart disease, stroke, and sometimes death. Perivascular adipose tissue (PVAT) is known as the adipose tissue (AT) surrounding all the blood vessels and plays a critical role in the pathogenesis of the vascular disease. In vascular pathologies, PVAT increases in volume and becomes dysfunctional, with altered cellular composition and molecular characteristics. Macrophages have been found to accumulate in PVAT during hypertension, which might be involved in the inflammation of hypertension. Inflammation has been shown to play an important role in hypertension; however, the exact mechanisms by which the activated immune cells partly lead to the development and maintenance of hypertension remain to be elucidated. The objective of this study is to determine the role of exercise in the inflammation of AT and PVAT by modulating the polarization of macrophages in hypertensive mice. Renin transgenic (R+) mice have been used as a hypertensive mice model. The PVAT, AT, and plasma samples were collected for the analysis of inflammatory cytokines, macrophages isolation, and polarization. The release of cytokines from AT and PVAT was determined by ELISA and the release of cytokines from plasma was determined by bio plex cytokine analysis. Our ELISA results did not show the changes of exercise on the release of cytokines in AT but could decrease the pro-inflammatory cytokines in PVAT. While our flow cytometry results showed that exercise affected the macrophage polarization in adipose tissue but not in PVAT. Cytokine analysis of plasma samples showed a decrease in pro-inflammatory cytokines IFN-g and IL-6, as well as anti-inflammatory cytokines IL-4 and IL-13, while an increase in IL-10 was noted, which might be related to effects of exercise by alleviating t (open full item for complete abstract)

Committee: Ji C. Bihl M.D., Ph.D. (Advisor); Yanfang Chen M.D., Ph.D. (Committee Member); Ravi P. Sahu Ph.D. (Committee Member) Subjects: Pharmacology; Toxicology

Master of Science, University of Toledo, 2019, Bioengineering

Musculoskeletal tissue injuries affect around 1 in 3 Americans and 1.7 billion people worldwide. This is a huge economic burden, costing an estimated $120 billion in the US alone. With limited success from surgery or subcutaneous injections of medicine, where only temporary relief or complications can occur, alternative measures should be explored. Injectable biologically-loaded hydrogels are one avenue and act as drug delivery systems. They provide a minimally invasive approach to release biologics in a sustained and controlled manner to provide long-lasting relief without toxic effects and with less risk of surgical complications. In this study, the immunological application of a previously-developed nanofibrous PCL-interspersed collagen hydrogel, (PNCOL) was explored by loading PNCOL with the cytokine IL-4 and identifying its effect upon macrophages. Furthermore, the effect of a simulated digestive inflammatory environment (DIE) had upon protein release kinetics as well as scaffold integrity were characterized. Genipin crosslinking was then explored to improve scaffold resistance to degradation, and an optimal genipin concentration was identified to impart sufficient scaffold crosslinking, increased mechanical strength, and a prolonged release profile, with minimal cytotoxic effects. Lastly, the immunomodulatory effect of IL-4 released from crosslinked and uncrosslinked scaffolds were investigated through identifying the impact of IL-4 on macrophage differentiation. The IL-4 released from PNCOL polarized macrophages toward an anti-inflammatory, pro-healing state, while genipin crosslinking with and without IL-4's presence appeared to lower macrophage activity.

Committee: Eda Yildirim-Ayan PhD (Advisor); Eda Yildirim-Ayan PhD (Committee Chair); Halim Ayan PhD (Committee Member); Arun Nadarajah PhD (Committee Member) Subjects: Biology; Biomedical Engineering; Biomedical Research; Cellular Biology; Materials Science

Doctor of Philosophy in Engineering, Cleveland State University, 2019, Washkewicz College of Engineering

Controlled inflammation is crucial for normal wound healing. Our main aim in this study was to investigate the effect of loss of tumor necrosis factor-stimulated gene-6 (TSG-6) in cutaneous wound closure and inflammation. TSG-6 by its enzymatic action modifies the extracellular matrix molecule, hyaluronan (HA), through the transfer of heavy chain (HC) proteins from inter-α-trypsin inhibitor to form HC-HA complexes. Both TSG-6 and HC-HA have been associated with inflammation. Here, we showed that loss of endogenous TSG-6 and HC-HA in TSG-6 null mice results in significantly delayed wound closure and differential neutrophil recruitment compared to wildtype mice. Both of these phenotypes were successfully rescued by reintroduction of TSG-6 into null wounds. We also observed leukocyte recruitment behavior upon chemical injury and propose interesting differences between wildtype and TSG-6 null animals. Further, we showed that levels of the pro-inflammatory cytokine TNFα, and the presence of M1 proinflammatory macrophages, were elevated in TSG-6 null wounds compared to wildtype wounds. To facilitate the analysis of wound macrophages, we have described a detailed protocol to isolate single cells from cutaneous wounds. In a nutshell, our study indicates that TSG-6 is required for normal wound closure and plays an important role in regulating inflammation during wound repair.

Committee: Edward V. Maytin MD, PhD (Committee Chair); Nolan B. Holland PhD (Committee Member); Mark Aronica MD (Committee Member); Margot Damaser PhD (Committee Member); Carol de la Motte PhD (Committee Member) Subjects: Biology; Biomedical Research; Immunology; Molecular Biology

Master of Science (MS), Wright State University, 2019, Microbiology and Immunology

Macrophages are phagocytic cells located in tissues, organs and even circulated within our body as white blood cells. They are critical in detecting tissue damage and infection. Resident tissue macrophages initiate the signals for inflammation recruiting neutrophils and blood monocytes which mature into macrophages at sites of infection and in the resolution of inflammation. Based on the local cytokine milieu in tissue sites, macrophages may be polarized into pro-inflammatory M1 or anti-inflammatory M2 phenotypes. Receptor tyrosine kinase Mer (MERTK) helps in clearing dead neutrophils and other apoptotic cells from damaged tissue sites preventing chronic inflammation and autoimmune disorders. MERTK aids in the maintenance of tissue homeostasis and wound healing. Phosphatidylserine (PtdSer) present on the surface of apoptotic cells release “eat me” signals which are recognized by the two “bridging ligands” of MERTK receptor, Gas6 and ProS. The binding of the ligands to PtdSer initiates intracellular signals leading to phagocytosis of the cell. MERTK receptor is expressed mostly on M2c macrophages. The current study explores the expression rate of the phagocytic receptor MERTK, on macrophages polarized with either IL-10 (M2c ells) or IL-4 or IL-13 (M2a macrophages) following treatment with the suppressor of cytokine signaling SOCS3 in comparison with macrophage polarization with only IL-10 or IL-4 or IL-13 . The current study exhibits an enhancement in the expression of the phagocytic MERTK receptor on the surface of IL-10 polarized M2c macrophage when treated with SOCS3 in comparison to IL-10 polarized M2c macrophage, IL-4 polarized M2a macrophage and IL-13 treated M2a macrophage. IL-13 polarized M2a macrophage also shows an increase in the expression of MERTK receptor which is similar to a previous study where a similar receptor to MERTK termed “Axl receptor” is enhanced by IL-13 treatment on bone- marrow derived macrophage. SOCS3 when treated with IL-13 polar (open full item for complete abstract)

Committee: Nancy J. Bigley Ph.D. (Advisor); Dawn P. Wooley Ph.D. (Committee Member); Marjorie Markopoulos Ph.D. (Committee Member) Subjects: Immunology; Microbiology

MS, Kent State University, 2018, College of Arts and Sciences / Department of Chemistry

NIELSEN, FREDERICK, M.S. August 2018 CHEMISTRY & BIOCHEMISTRY HARNESSING MACROPHAGE POLARIZATION FOR PLATINUM-BASED IMMUNOCHEMOTHERAPY (74 pp.) Director of Thesis: Yaorong Zheng Ovarian cancer is the leading cause of death among gynecological cancers in the Western World with a 5-year survival rate of 46.5%. One of the major contributors to the deadliness of this malignancy is the fact that over half of patients will develop an acquired resistance to traditional platinum-based chemotherapies. This acquired chemoresistance is a major issue in treating ovarian cancer and requires alternative treatment strategies. One alternative strategy is to utilize the immune system for its natural tumor killing potential. Among the candidates for immunotherapy, macrophages display an interesting target for improving therapeutic outcomes. Macrophages are the most abundant immune cell type within the tumor environment. These tumor associated macrophages (TAMs) can display either tumoricidal (M1) or tumor promoting (M2) phenotypes. TAMs primarily exist in an M2-like state, and higher M1/M2 ratios have been correlated with improved therapeutic outcomes in ovarian cancer. Utilizing the beneficial characteristics of M1 macrophages may lead to improved therapeutic outcomes in combination with traditional platinum-based therapy for a combined immunochemotherapeutic effect. In order to develop this strategy of treatment, first the efficacy and interactions of polarized macrophages and platinum-based chemotherapeutics on ovarian cancer must be established. This study demonstrates the tumoricidal potential of M1 macrophages against ovarian cancer cell lines and this tumoricidal actions functions through increase in apoptosis of cancer cells. The killing action is mainly attributed to NO and TNFa generation by the M1 macrophages. Cisplatin, a Pt(II) chemotherapeutic with many derivatives that are widely used, is seen to be a poor candidate for combined immunochemotherapeutic use beca (open full item for complete abstract)

Committee: Yaorong Zheng Dr. (Advisor); Songping Huang Dr. (Committee Member); Sanjaya Abeysirigunawardena Dr. (Committee Member) Subjects: Biochemistry; Chemistry

Master of Science (MS), Wright State University, 2014, Microbiology and Immunology

In this study, the human leukemic monocyte lymphoma cell line U-937 was used as an in vitro model for monitoring monocyte/macrophage differentiation. Phorbol 12- myristate (13) (PMA) was used to activate U-937 cells into macrophage-like cells (M0). After 24 hours of PMA treatment, non- adherent U-937 cells became tightly adherent to the culture plates forming M0 cells. M0 cells were then polarized into the M1 macrophage phenotype by treatment with LPS and IFN-¿ for another 24 hours. Each of the cytokines IL-4, IL-13, or IL-10 was applied separately to three M0 cultures for 24 hours to induce the M2 macrophage phenotype. M1 and M2 phenotypes displayed distinct morphological characteristics. M1 cells appeared large, with cellular processes (pseudopodia), and intracellular vacuoles while the M2 cells large aggregated into large masses. The undifferentiated U--937 cells expressed less CD206 and CD86 but greater amounts of CD163, CD80, and CD200R than did the differentiated U937 cells (M0 macrophages). These observations suggest that the differentiated M0 cells would be better at antigen presentation since they expressed a 6-fold increase the CD86 costimulatory molecule and half the amount of the CD80 costimulatory molecule as did undifferentiated U937 cells. M1 polarized macrophages expressed lesser amounts of CD14, CD86, CD80, CD163, CD206, and CD200R than M0 cells which may reflect the production of toxic substances such as reactive oxygen molecules, nitric oxide and TNF-a. Both the differentiation and polarization processes caused decreases in cell viability no difference seen between M0 and M1 populations at the 24 hour observation time. Marked differences in expression of these CD markers were obvious in the M2 subpopulations with the IL-4-polarized M2 cell showing marked elevations in expression of CD206 and CD86 and the IL-13-polarized M2 cells showing marked increase in expression of CD14. These differences highlight the plasticity of the macrophage in (open full item for complete abstract)

Committee: Nancy Bigley Ph.D. (Advisor); Barbara Hull Ph.D. (Advisor); Gerald Alter Ph.D. (Committee Member) Subjects: Immunology; Microbiology

Master of Science (MS), Wright State University, 2012, Microbiology and Immunology

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 are especially effective at mediating resistance against intracellular parasites and tumors. Arginine metabolism in M1 macrophages is characterized by high levels of inducible nitric oxide synthetase (iNos), and this is used as a marker for polarization of macrophages to the M1 phenotype. M2 macrophages, by contrast, produce anti-inflammatory molecules, have high levels of scavenger, mannose, and galactose-type receptors, and arginine metabolism is shifted to production of ornithine and polyamines via arginase. Arginase, encoded by the ARG1 gene, is considered to be one of the hallmarks of the M2 phenotype, and is one of the most specific markers used to determine polarization to that phenotype. Polarization to one phenotype or another is not permanent, and macrophages can be polarized directly from one state to the other directly by addition of appropriate cytokines (IFNy, LPS, TNFa for M1, IL-4, IL-13, IL-10, TGFb for M2). The state of macrophage polarization can be determined by examining a population of macrophages for tell-tale products of one state or another (ROS, RNS, TNFa, IL-1, IL-6, IL-12, or IL-23 for M1, IL-10, TGFb, PDGF, VEGF, EGF, and arginase for M2). Determining macrophage polarization has implications in health outcomes- M1 macrophages excel at fighting parasites and fig (open full item for complete abstract)

Committee: Nancy Bigley PhD (Committee Chair); Barbara Hull PhD (Committee Member); Thomas Brown PhD (Committee Member) Subjects: Microbiology

Master of Science (MS), Wright State University, 2012, Microbiology and Immunology

In our current study we examined the effects of HSV-1 challenge on J774A.1 macrophages polarized to either a proinflammatory (M1) or anti-inflammatory (M2) phenotype. Polarized J774A.1 macrophages were characterized using CD14-CD86 and SOCS1-SOCS3 expression levels. SOCS proteins are a family of proteins that are capable of inhibiting cytokine-signaling pathways. HSV-1 up regulates expression of SOCS1 protein levels in infected cells, inhibiting the ability of infected cells to produce proinflammatory products (Nowoslawski Akhtar and Benveniste, 2011). This study shows that signals within the microenvironment play a greater role in macrophage polarization, and SOCS1-SOCS3 expression levels, than does HSV-1 challenge. M1 macrophages showed morphological changes following polarization, a significant decrease in cell viability, a two-fold increase in the number of CD14+-CD86+ cells, similar levels of SOCS1 expression, and a 11-fold decrease in SOCS3 expression when compared to control cells. M2 macrophages also exhibited morphological changes, a slight decrease in cell viability, a 26.0% decrease in the number of CD14+-CD86+ cells, and SOCS1-SOCS3 expression levels similar to that of control cells. Following HSV-1 challenge (0.1 MOI), the majority of M1 macrophages and M2 macrophages appeared rounded, possibly due to disruption of actin filaments. Virus-infected M1 macrophages showed a slight decrease in cell viability when compared to uninfected M1 macrophages. Additionally, the number of CD14+-CD86+ cells of both M1 and M2 phenotypes decreased. M1 macrophages exhibited a 39.9% decrease, while M2 macrophages exhibited a 13.2% decrease. SOCS1 expression levels remained relatively unchanged in virus-infected M1 macrophages, while SOCS3 expression levels increased by 30.4% at 24 hours after infection. Increase in SOCS3 levels is hypothesized to be a protective response of infected M1 macrophages due to the release of high levels of proinflammatory molecules. Alternativel (open full item for complete abstract)

Committee: Nancy Bigley PhD (Advisor); Barbara Hull PhD (Committee Member); Julian Cambronero PhD (Committee Member) Subjects: Immunology; Microbiology

Master of Science (MS), Wright State University, 2013, Microbiology and Immunology

The U937 cell line is an oncogenic human monocyte cell line. These monocytes have the potential of differentiating into either macrophages or dendritic cells (Lawrence et al., 2011). This differentiation pattern depends on the characteristics of the tissue microenvironment (Kigerl et al., 2009). PMA (Phorbol 12-Myristate 13-Acetate) is a phorbol ester capable of transforming monocytic cells toward the macrophage pathway. Upon treatment with PMA, U937 cells under-go a series of morphological and functional changes. Traditionally monocytic cell lines are used as a model of macrophage function, because current human macrophage cell lines require a T-cell conditioned growth medium and contact with irradiated peripheral blood leukocytes (PBLs) to propagate (Lee et al., 1997). The PMA-treated monocyte is referred to as “macrophage-like,” meaning that the properties of the transformed cell line are not yet fully understood (Dockrell et al., 2010). These macrophages are clinically significant for possible cancer immunotherapy experimentation. Recently, two divergent macrophage subsets have been identified: M1 (pro-inflammatory) and M2 (anti-inflammatory). These macrophages are differentiated based on the cytokines present in the extracellular matrix (Kigerl et al., 2009). In order for the U937 cell line to be represented as an effective macrophage model, the ability of the cell line to polarize must be analyzed. This study is a review of the features necessary to convert the human U937 cell line into M1 or M2 morphological and functional subsets.

Committee: Nancy Bigley Ph.D. (Advisor); Barbara Hull Ph.D. (Committee Member); Gerald Alter Ph.D. (Committee Member) Subjects: Biochemistry; Biology; Immunology; Microbiology; Pathology