Doctor of Philosophy, The Ohio State University, 1973, Graduate School

Committee: Not Provided (Other) Subjects: Agriculture

Doctor of Philosophy, The Ohio State University, 1959, Graduate School

Committee: Not Provided (Other) Subjects: Biology

Master of Science, The Ohio State University, 2005, Graduate School

Committee: Not Provided (Other) Subjects:

Master of Science, The Ohio State University, 2006, Graduate School

Committee: Not Provided (Other) Subjects:

PhD, University of Cincinnati, 2022, Medicine: Molecular Genetics, Biochemistry, & Microbiology

Bone Morphogenetic Proteins (BMPs) are the largest subgroup of the Transforming Growth Factor ß (TGFß) superfamily, one of the fundamental protein signaling pathways in biology. BMPs are involved in regulating numerous biological functions, with a particular focus on development, immune modulation, cell homeostasis and wound healing. When dysregulated, aberrant BMP signaling can indue a host of developmental and autoimmune disorders, as well as many different cancers. Given the wide array of biological functions BMPs regulate, precise regulation of signaling is a key component of their biology. Mechanistically, these secreted dimeric signaling proteins function by forming complex with two type 1 and two type 2 serine/threonine kinase receptors on the cell surface to drive signaling by intracellular SMAD proteins. Accordingly, the regulation of these potent signaling molecules in the extracellular space is a vital area of study. The purpose of the work outlined in this thesis is to explore certain understudied mechanisms of extracellular modulation of BMP signaling. We particularly focused on studying these mechanisms not in isolation, but rather as they actually exist in nature, as part of a complex environment with many competing biomolecules. We present studies contrasting related protein antagonists with different function in an attempt to gain insight into the key components needed for BMP inhibition. In addition, we explore a newly discovered interaction between the BMP and Wnt signaling pathways, where BMP ligands may directly antagonize canonical Wnt signaling. Lastly, we describe a procedure for the production of artificial BMP heterodimeric signaling molecules using chains with differential activity with respect to receptor preference, antagonist targeting, and affinity to the extracellular matrix. These asymmetrical signaling molecules were then used to isolate the key components of biological function across multiple different experimental systems. Overal (open full item for complete abstract)

Committee: Thomas Thompson Ph.D. (Committee Member); Rhett Kovall Ph.D. (Committee Member); Aaron Zorn Ph.D. (Committee Member); James Wells Ph.D. (Committee Member); Michael Tranter Ph.D. (Committee Member) Subjects: Biochemistry

Master of Science, The Ohio State University, 2021, Psychology

Objective: This thesis aims to identify novel relationships between modifiable physical and health variables, Alzheimer's disease (AD) biomarkers, and cognitive function in a cohort of older adults with mild cognitive impairment (MCI). Methods: Metrics of cardiometabolic risk (e.g., body mass index), stress (e.g., cortisol), inflammation (e.g., c-reactive protein), neurotrophic/growth factors (e.g., brain-derived neurotrophic factor), and AD (e.g., plasma tau) were assessed in 154 MCI participants from the Alzheimer's Disease Neuroimaging Initiative (ADNI) at baseline (mean age = 74.1; sd =7.5; mean education = 16.0; sd = 2.9). Of these 154 participants, 126 had 2-year follow-up data available for analyses (mean age = 74.0; sd = 7.6; mean education = 16.0; sd = 2.9). Participants also completed a comprehensive neuropsychological battery. Individual test scores and composite scores of memory and executive function published by ADNI were assessed. Partial least squares correlation (PLSC), an unbiased and flexible multivariate technique, was employed to examine cross-sectional associations among these physiological variables and cognition. Partial least squares regression (PLSR), a multivariate technique that defines optimal combinations of variables that best predict an outcome, was used to identify which, if any, of these physiological variables are important in predicting memory or executive function at 2-year follow-up. Results: The PLSC analysis revealed a latent variable describing a unique combination of AD biomarkers, neurotrophic/growth factors, education, and stress that were significantly associated with specific domains of cognitive function, including episodic memory, executive function, processing speed, and language, representing 45.2% of the covariance in the data. Age, BMI, and tests of basic attention and premorbid IQ were not significant. The PLSR analyses revealed that baseline metrics of cardiometabolic function, inflammation, and AD biomarkers (open full item for complete abstract)

Committee: Scott Hayes Ph.D. (Advisor); Jasmeet Hayes Ph.D. (Committee Member); Ruchika Prakash Ph.D. (Committee Member) Subjects: Aging; Clinical Psychology

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

Mouse models of eosinophil-associated diseases have been used to study the mechanisms of disease pathogenesis. In this study, mouse-derived bone marrow cells were used in long-term (6 and 9 months) cell cultures of differentiated eosinophils and macrophages. IL-5 was used to differentiate the stem cells to eosinophils and GM-CSF was used to propagate macrophages from the bone marrow stem cells. The maximum time period for observing the eosinophil cultures was 252 days which is censurably longer than the 18 days culture period observed by others. The results were assessed by describing the microscopic cell morphology by Wright staining, modified Giemsa staining and protein expression by immunofluorescent staining. The GMCSF-stimulated bone marrow cultures produced classically appearing monocyte/macrophages throughout the study and were used to compare the development of the eosinophils over the long-term period of observation. Differentiation of the BM cells was carried out using with growth factors (SCF, FLT3L) and cytokines (IL-5, GM-CSF) over the 252 days period. The most suitable culture plate for long-term of cell growth were thee 60 mm petri dishes. At 252 days, the eosinophils exhibited as bi-lobed nuclear shapes, comparable with human eosinophils. Dendrite-like ramifications were observed on the surfaces of these eosinophils. Long term culture of eosinophils in the presence of IL-5 contributed to formation of eosinophil extracellular traps (EETs) areas. Within the EETs the cells surface of eosinophils developed holes; the nucleus of such cells lost the “ring-like” or “lobular” morphology and appeared in de-condensed fashion. Within the EETs, the plasma membranes of eosinophils developed the protrusions containing cytoplasmic granules. The EETs and protrusions had not been observed previously in the mouse eosinophil models in vitro but were described in human eosinophils. Consequently, the long-term culture of mouse bone-marrow derived eosinophil (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

Master of Science (MS), Wright State University, 2017, Pharmacology and Toxicology

Introduction Extracellular Microvesicles (EMVs) can carry genetic messages and biologically active proteins throughout tissues and the body. Because of their transport capabilities, EMVs play an important role both diseased and healthy conditions. For example, EMVs play an important regenerative role in many damaged tissues. In the current studies, we examine the role of EMVs in epithelial wound healing. The potential use of EMVs as drug delivery vehicles has gained considerable scientific interest because they can be delivered in circulation, can be targeted to specific areas/cells, and can pass natural barriers. In the current work, we investigate the potential of EMVs or EMVs loaded with growth factors as a tool to enhance cell migration in order to accelerate epithelial wound healing. Material and Methods Spontaneously immortalized skin keratinocyte and macrophage cells were stressed for 48 h by serum free media to enhance the release of the EMVs from keratinocytes (KMVs) and macrophages (MMV). The EMVs from both cell lines were isolated and collected using a centrifugation process. Specifically, the collected serum free media were centrifuged at 4 °C (500 × g for 10 minutes followed by 2,000 × g for 20 minute). The supernatant was then centrifuged at 24,000 × g for 2 hours to isolate EMVs. EMVs were “loaded” with growth factors by incubating them for 1.5 h at room temperature with PDGF, TGF-ß, VEGF, and FGF (25ng/ml per each). These “loaded” EMVs were then ultra-centrifuged at 176,000 x g for 3 h to re-pellet the loaded microveiscles derived from keratinocytes KMVs (LKMVs) or macrophages MMVs (LMMVs). In order to evaluate the role of microvesicles on cutaneous wound healing, we chose the in vitro wound scratch assay to evaluate the cell migration rate and the wound healing percent after adding of KMVs, LKMVs, MMVs, and LMMVs separately to Epidermal keratinocytes culture. Epidermal keratinocytes were plated into 6 well plates, and wound scratch was made usin (open full item for complete abstract)

Committee: Richard Simman M.D. (Advisor); Debra Mayes Ph.D. (Advisor); Ulas Sunar Ph.D. (Committee Member); Terry Oroszi Ed.D. (Committee Member) Subjects: Pharmacology

Master of Engineering, Case Western Reserve University, 2017, Biomedical Engineering

Lower-limb fracture exhibits a limited capacity to heal critically sized defects and biomimetic tissue engineering is a promising approach for addressing this clinical need. Here, scaffold-free tubular mesenchymal condensations featuring temporally controlled TGF-Β1 and BMP-2 morphogen release from incorporated microparticles were engineered to form self-assembled rings and tubes. In vitro culture, subcutaneous, and femoral defect implantation was performed to establish bone forming capacity with the treatment groups: 1) TGF-Β1, 2) BMP-2, or 3) BMP-2+TGF-Β1. Bone formation was evaluated by biochemical, μCT, and histological analyses. Dual-delivery enhanced bone volume versus single morphogens at 6wks, and histology revealed bone within tubular geometries with enhanced cartilage, mimetic of endochondral ossification. Overall: 1) geometry of scaffold-free mesenchymal condensations guided 3D ossification, 2) BMP-2+TGF-Β1 presentation augmented ectopic bone formation, and 3) tubular architecture promoted femoral defect bridging over random organization.

Committee: Eben Alsberg Dr. (Advisor); Steven Eppell Dr. (Committee Member); Ozan Akkus Dr. (Committee Member) Subjects: Biology; Biomedical Engineering; Biomedical Research; Cellular Biology; Engineering; Health Sciences; Histology; Medical Imaging; Microbiology; Morphology

Master of Science (MS), Wright State University, 2017, Pharmacology and Toxicology

Introduction: Wound healing is a sophisticated dynamic process that involves complex coordination among a variety of resident cells in a suitable extracellular environment. Chronic wounds are defined as wounds that fail to heal within a period of 3 months. Negative pressure wound therapy (NPWT) is a closed suction drainage system is used to enable mass transport of fluid from the body as an adjunct to surgical procedures. (Oasis-ultra) is a triple layer extracellular matrix containing different types of glycosaminoglycans (GAGs) like heparin sulfate, hyaluronic acid and chondroitin sulfate. In addition, it has adhesion molecule such as fibronectin and laminin along with various growth factors. Extracellular vesicles, (EVs); microvesicles and exosomes are a diverse family of membrane bound vesicles laden with various proteins, nucleic acids, and lipids that cells release to the extracellular environment. EVs play a crucial role in cell to cell communication, as they carry signaling molecules, like lipids, proteins, mRNAs, and miRNAs. We hypothesize that there is a correlation between the concentration of EMVs and the percentage of wound healing in treated chronic wounds and the healing percentage will be enhanced by the combination of Oasis ultra and NPWT. A prospective, multi-centered, randomized, single-blinded clinical trial that permitted by the Ethics Committee of the Copernicus was conducted to study whether the combination of Oasis ultra and NPWT will enhance the healing of chronic wounds when compared with only NPWT, to measure the concentration of EMVs in the collected wound fluids and correlate it with the percentage of wound healing and to analyze the extracellular microvesicles composition to look for growth factors, chemokines and cytokines that play role in the wound healing Material and Methods: Wound fluid samples obtained from 14 patients with stage IV trunk pressure ulcers. The patients were divided in two groups (7 in each group, n=7): control g (open full item for complete abstract)

Committee: Richard Simman M.D. (Advisor); David Cool Ph.D. (Committee Member); Jeffrey Travers M.D., Ph.D. (Committee Member) Subjects: Pathology; Pharmacology; Pharmacy Sciences; Philosophy of Science; Physiology

Doctor of Philosophy, The Ohio State University, 2001, Graduate School

Committee: Not Provided (Other) Subjects: Chemistry

Master of Science (MS), Wright State University, 2016, Pharmacology and Toxicology

Introduction: (Oasis-ultra) is an extra cellular collagen rich matrix derived from porcine intestinal sub-mucosa. A prospective, multi-centered, randomized, single-blinded clinical trial was conducted to study the effects of Oasis-ultra combined with negative pressure wound therapy (NPWT) on the healing rate of stage IV pressure wounds versus NPWT alone. Materials and Methods: Twelve subjects were involved in the study: six patients in the study group and six in the control group. NPWT was changed twice a week for all subjects, and Oasis-ultra was applied weekly. The wounds were measured weekly, and the healing rate was calculated for each subject for 12 weeks. The canisters were collected monthly for three months. For cytokine and growth factors analysis, 100 µl 1XPBS were added to the sample, and protein concentration was determined using the Bradford assay. A Bio-Rad BioPlex 96 well plate was set up with 50 µl of the sample and duplicated for cytokine analysis using Bio-Plex. Results: In the study group, the healing rate calculated at 12 weeks was found to be ~87% when compared to the control group, which was ~55%. Analysis of different growth factors, normally present in stage IV pressure wounds, revealed higher concentrations in the oasis-ultra treated group when compared with the control group. Additionally, the other proinflammatory cytokines that accused of wound chronicity were down regulated as a result of treating the subjects in the study group with oasis-ultra. Conclusion: Our study demonstrates that the use of Oasis-ultra accelerates the healing rate of stage IV pressure wounds when combined with NPWT. Also, in the Oasis-ultra treated group, the proinflammatory cytokines were successfully inhibited. At the same time, Oasis-ultra promoted and upregulated the beneficial growth factors that had positive impact on the healing rate.

Committee: Richard Simman M.D, FACS, FACCWS. (Advisor); David Cool Ph.D. (Committee Member); Yanfang Chen M.D., Ph.D. (Committee Member); Ji Bihl MD., Ph.D. (Committee Member) Subjects: Medicine; Pharmacology

Master of Science, The Ohio State University, 2015, Dentistry

Objective: The objective of the current study was to examine whether peri-implant bone tissue properties at the buccal region are different from those at the lingual region as a result of growth factor treatments at post-implantation healing periods. Methods: Four dental implant groups were used: titanium (Ti) implants, alumina-blasted zirconia implants (ATZ-N), alumina-blasted zirconia implants with demineralized bone matrix (DBM) (ATZ-D), and alumina-blasted zirconia implants with rhBMP-2 (ATZ-B). These implants were placed in mandibles of six male dogs. Nanoindentation elastic modulus (E) and plastic hardness (H) were measured for the buccal and lingual bone tissues adjacent and away from the implants at 3 and 6 weeks post-implantation. A total of 2281 indentations were conducted for 48 placed implants. Results: The peri-implant buccal region had less bone quantity resulting from lower height and narrower width of bone tissue than the lingual region. Buccal bone tissues had significant greater mean values of E and H than lingual bone tissues at each distance and healing period (p<0.007). Nearly all implant treatment groups displayed lower mean values of the E at the lingual bone tissues than at the buccal bone tissues (p<0.046) although the difference was not significant for the Ti implant group (p=0.758). Conclusions: The DBM and rhBMP-2 treatments stimulated more peri-implant bone remodeling at the lingual region, producing more immature new bone tissues with lower E than at the buccal region. Clinical Significance: This finding suggests that the growth factor treatments to the zirconia implant system may help balance the quantity and quality differences between the peri-implant bone tissues.

Committee: Damian Lee DDS, MS (Advisor); William Brantley PhD (Advisor); DoGooyn Kim PhD (Advisor) Subjects: Biomechanics

PhD, University of Cincinnati, 2000, Medicine : Interdisciplinary (Medical Science Scholars, Neuroscience)

Prolactin (PRL) is regulated by inhibitory and stimulatory factors from the hypothalamus and pituitary. Dopamine is the primary PRL-inhibitory factor, but acute elevations in PRL require stimulation by a PRL-releasing factor (PRF). PRF from the rat pituitary rapidly stimulated PRL release and localized to the intermediate lobe (IL). Partial purification of multiple PRF species from IL tumors differed in size and chromatographic properties. However, the primary structure of PRF has not been resolved. Our hypothesis was: a subpopulation of IL cells secretes a novel peptide that functions as a PRF. Transgenic POMC-Tag mice that develop IL tumors were used to investigate the following objectives: 1) determine if POMC-Tag mice with IL tumors develop hyperprolactinemia, 2) establish and characterize an IL cell line the produces PRF, 3) determine the biochemical properties of PRF, 4) purify PRF and determine its structure. Hyperprolactinemia was not observed in POMC-Tag mice from 20 to 120 days. Cells from two IL tumors were cloned into mIL cell lines that differed in cellular characteristics. As assessed by RT-PCR the mIL39, but not mIL5, cells expressed POMC and D2R gene products, characteristic of IL melanotrophs. The cell lineage of mIL5 cells remains undefined. Only the mIL5 cells, co-cultured with GH3/luc cells, stimulated PRL gene expression and release. PRF from mIL5 was secreted and bound heparin. Two heparin-binding proteins, FGF2 and HB-EGF, identified in mIL5 cells were potent PRL inducers. However, neither significantly contributed to the PRF activity from mIL5 as judged by Western blotting, heparin-affinity and immunoneutralization. Purification of PRF from mIL5 by heparin-affinity chromatography indicated multiple species that differed in chromatographic properties. Sequential chromatography was used to isolate PRF from cell extract and sequencing identified a peptide identical to an internal sequence of heparin-interacting protein (HIP/L29). The expression (open full item for complete abstract)

Committee: Nira Ben-Johnson (Advisor) Subjects:

MS, University of Cincinnati, 2007, Engineering : Electrical Engineering

In orthopaedics, current methods of drug delivery are technologically primitive in that they limit the control over dosing parameters including amplitude, frequency, and chronology of delivery. The research in this thesis works toward a sonofluidic delivery system that would allow control over these parameters. A drug-containing textile would be placed in-vivo at the delivery site, remaining non-permeated until the application of ultrasound. With ultrasound, the ambient fluid would permeate the textile, mix with the enclosed product, and release the product via diffusion. Chronologically separate delivery may be achieved by adjusting parameters of the textile and applied ultrasonic signal. This would allow delivery of product in controlled quantities, thus maximizing product absorption. This thesis discusses the design, fabrication, and testing of six generations of sonofluidic devices, along with future research directions, where recommendations are made for the design of a device conforming more to the standards of a commercial prototype.

Committee: Dr. Jason Heikenfeld (Advisor) Subjects:

Doctor of Philosophy, The Ohio State University, 2006, Veterinary Clinical Sciences

Complicated healing of articular fractures represents a clinical challenge and a financial burden on the health care system. Bone marrow-derived mesenchymal stem cells (BMDMSC) hold promise for targeted osteogenic differentiation and can be augmented by delivery of genes encoding bone morphogenetic proteins (BMP). Osteogenic differentiation of BMDMSC was investigated using two BMP genes. Cultured BMDMSC were transduced with adenoviral vectors containing human BMP2 or BMP6 in either sustained in monolayer or suspended in alginate for 22 days. Adenovirus (Ad)-BMP-2 and Ad-BMP-6 transduction resulted in abundant BMP-2 and BMP-6 mRNA and ligand expression in monolayer culture and BMP-2 ligand expression in alginate. Ad-BMP-2 and Ad-BMP-6 transduced BMDMSC in monolayer had earlier alkaline phosphatase-positive staining and mineralization and were sustained for a longer duration than untransduced or Ad-ß-galactosidase-transduced cells. Gene expression studies at day 2 confirmed an inflammatory response to the gene delivery process. Up-regulation of genes consistent with response to BMP exposure and osteogenic differentiation occurred in BMP-transduced cells. These data support that transduction of BMDMSC with Ad-BMP-2 or Ad-BMP-6 can accelerate osteogenic differentiation and mineralization of stem cells. BMP-2-transduced stem cells suspended in alginate culture may be a practical carrier system to support bone formation in vivo. A distal femoral articular osteotomy model was created in the nude rat to study articular fracture healing. Osteotomies were treated with BMDMSC, wild-type (NoAd) or transduced with Ad-BMP-2. Cells were delivered in alginate (ALG) or injected in saline. Controls were empty ALG, saline injections, direct Ad-BMP-2 injection, and untreated osteotomies. Healing was compared using quantitative micro-computed tomography, fluorescent labeling, and histology. At day 14, osteotomy gap area in the Ad-BMP-2 ALG group was significantly greater than other grou (open full item for complete abstract)

Committee: Alicia Bertone (Advisor) Subjects:

Doctor of Philosophy, The Ohio State University, 2005, Pharmacy

Our laboratory reported that acidic and basic fibroblast growth factors (aFGF/bFGF, FGFs) confer broad-spectrum chemoresistance in solid tumors. The four studies in this dissertation tested the hypothesis that the combination of these two growth factors offers broad-spectrum protection against chemotherapy-induced alopecia (CIA). In chapter 2, we established and characterized CIA animal models by different chemotherapeutic agents representing four major classes of anticancer drugs, i.e., alkylators (cyclophosphamide), topoisomerase 2 inhibitors (doxorubicin), antimicrotubules (paclitaxel), and antimetabolites (cytosine arabinoside, or ara-c). In chapter 3, we evaluated the pharmacodynamic endpoints in the two CIA animal models. The data showed that the chemotherapeutic agents induced dermal layer shrinkage, reduced hair bulb diameter, shortened hair follicle length, altered hair bulb matrix cell proliferative activity and induced hair follicular apoptosis. Paclitaxel induced disruptions of hair follicle melanogenesis in the black C57BL-6 mice resulting in relocation of melanin to ectopic hair bulb locations. The collective data indicated that hair bulb matrix and outer root sheath (ORS) were the two major targets of chemotherapy in hair follicles. In chapter 4, we evaluated the protective effect of subcutaneous FGFs against CIA in the two animal models. The results showed that FGFs offered broad-spectrum protection against CIA by all four chemotherapeutic agents. In addition, FGFs accelerated the hair regrowth after CIA by high dose cyclophosphamide. Chapter 5 further investigated the protective effect of topical FGFs dissolved in 75% dimethyl sulfoxide (DMSO) against CIA. The data showed that topical FGFs reversed CIA by all four chemotherapeutic agents in the animal models. The data further showed that no or insignificant exposure of bFGF after subcutaneous or topical delivery of bFGF, suggesting that applying FGFs to the scalp will not compromise the efficacy of (open full item for complete abstract)

Committee: Jessie Au (Advisor) Subjects:

Doctor of Philosophy, The Ohio State University, 2003, Dentistry

Research indicated that psychological stress impaired wound closure by >40%. Here, it was hypothesized that stress adversely affected reparative processes during the proliferative phase of healing, leading to impaired wound closure. Data presented herein demonstrate that wound contraction and angiogenesis are significantly impaired in restraint stressed (RST) mice. Contraction was impaired by >46% in RST mice. Fibroblast migration and myofibroblast differentiation, processes important in contraction, were delayed in wounds of RST mice. Real-time PCR and western blot data demonstrated decreased expression of Sm&alphaA, a marker of myofibroblast differentiation. Members of the TGF-β superfamily are thought to regulate fibroblast migration and myofibroblast differentiation. Expression of TGF-&beta1 mRNA was downregulated by >25% (p<0.05) in RST mice, but not the expression of TGF-&beta2 or -&beta3. Although TGF-&beta1 mRNA was reduced in RST mice, no significant differences were detected in active or total TGF-&beta1 protein expression. Thus, the present data indicate that stress delays wound contraction and myofibroblast differentiation through a TGF-&beta-independent mechanism. Data from the present study also indicate reduced microvessel density and hemoglobin content in wounds of RST mice, suggesting impairment of angiogenesis. mRNA expression of angiogenic growth factors, including VEGF, FGF-1, FGF-2, and Ang-2, was downregulated in the wounds of RST mice. Downregulation of VEGF mRNA expression by 35 % on days 3 and 5 post-wounding, translated into reduced protein levels in the wounds of RST mice as indicated by ELISA and western blot analysis. Thus, dysregulation of angiogenic growth factor expression and a diminished angiogenic response during early healing is likely to contribute to the overall impairment of wound healing in RST mice. Since growth factor expression is potentially regulated by endogenous glucocorticoids it was hypothesized that RU486 would resto (open full item for complete abstract)

Committee: Phillip Marucha (Advisor) Subjects: Health Sciences, Dentistry

Doctor of Philosophy, Case Western Reserve University, 1994, Neurosciences

Nerve growth factor (NGF) is the prototypic member of the neurotrophin family, which are highly related trophic factors required for the development and maintenance of populations of central and peripheral neurons. NGF elicits its biological actions through binding to the Trk receptor, initiating a signaling cascade propagated through the cytosol primarily by regulated protein phosphorylation resulting from serial activation of protein kinases. Protein kinases mediate the transduction of this signal into alterations in gene transcription through the phosphorylation of transcription factors, leading to the synthesis of new protein products responsible for the eventual biological response. NGF stimulation of PC12 cells induces the differentiation of these cells into a neuronal phenotype. An immediate effect of NGF action is the transcription and synthesis of c-Fos, a bifunctional transcriptional regulator and phosphoprotein. c-Fos acts as a transcriptional activator, but can also repress transcription from some promoters, including its own. Phosphorylation of c-Fos is responsible for its ability to exhibit transrepressive activity, and potential phosphorylation sites at the C-terminus of this protein are required for this function. In vivo, c-Fos becomes phosphorylated at these sites by a growth f actor-activated protein kinase. I have identified a NGF-stimulated, depolarization-insensitive Fos kinase in PC12 cells using a peptide substrate corresponding to a sequence within the C-terminus of c-Fos. This enzyme is a novel protein kinase and phosphorylates authentic c-Fos at its C-terminus, likely at Ser362, a site required for transrepression. Growth factor responsive Fos kinase activity has been detected in fibroblasts, lymphocytes, and epidermal cells, indicating that this enzyme is widely expressed. NGF stimulation of Fos kinase requires that the enzyme be phosphorylated at serine/threonine residues. Fos kinase has been purified to near homogeneity from PC12 cells (open full item for complete abstract)

Committee: Gary Landreth (Advisor) Subjects: Biology, Neuroscience

Doctor of Philosophy, Case Western Reserve University, 1991, Pathology

Cellular interactions which occur at tissue implant interfaces may determine the biocompatibility of implanted devices. These studies investigate the macrophage and its products, which are hypothesized to be partially responsible for the long term biocompatibility of implanted materials. Alterations in the production of cytokines and growth factors IL-1-B, IL-1-A, TNF-A, TGF-A, TGF-B and IL-6 by activated monocytes in response to biomedical polymers were evaluated. The polymers were studied with or without preadsorbed human blood proteins IgG, fibrinogen, fibronectin, hemoglobin and albumin due to the initial protein adsorption event upon implantation of foreign materials in vivo. The biomedical polymers Biomer, Polyethylene, Polydimethylsiloxane, expanded Polytetrafluoroethylene and Dacron were selected due to their current medical application. These studies utilized two different controls to evaluate the data: nonprotein preadsorbed polymers and tissue culture treated polystyrene due to the nature of the in vitro assay system. The results of these studies show that there was a polymer and protein dependent alteration in the activity of activated monocytes/macrophages at the surface of bio medical polymers determined by alterations in monocyte secretion of IL-1-B, TGF-A and IL-6. The production of TNF-A, TGFB and IL-1-A was similar for all polymer and protein combinations. Down regulation of functional IL-1 activity was observed when protein preadsorbed polymers were compared to the protein preadsorbed polystyrene. Enhancement in functional IL-1 activity was observed when the polymers were compared to their respective nonprotein preadsorbed polymer controls. The monocyte culture supernatants stimulated fibroblast proliferation in a protein and polymer dependent manner. This suggests that certain polymers and adsorbed proteins may result in decreased fibroblast proliferation which may be important when considering fibroplasia, wound healing and tissue encapsulation (open full item for complete abstract)

Committee: James Anderson (Advisor) Subjects: Health Sciences, Pathology