PhD, University of Cincinnati, 2009, Medicine : Molecular and Developmental Biology

Lung remodeling occurs in many chronic lung diseases, including pulmonary fibrosis, bronchopulmonary dysplasia (BPD), and asthma. The signaling pathways that mediate lung remodeling are largely unclear; however, clinical studies in patients have reported increases in the epidermal growth factor receptor (EGFR) and its ligands, including epidermal growth factor (EGF) and transforming growth factor-alpha (TGF-α). Our studies examined the role of the EGFR pathway in several models of lung disease. Previous work has shown that increases in TGF-α expression in neonates disrupts both airway and vascular morphogenesis and causes remodeling. Induction of TGF-α and EGFR in adult mice causes progressive pulmonary fibrosis that is largely reversible once TGF-α overexpression is discontinued. Here, we show that increased expression of TGF-α during the saccular phase of lung morphogenesis caused a severe and lethal lung disease with pathologic characteristics similar to those seen in patients with BPD. Since this prenatal TGF-α induced disease was different from the diseases seen after neonatal and adult induction, the timing of EGFR activation plays a vital role in determining the disease outcome. Microarray analysis of mRNA from the lungs of TGF-α transgenic mice identified a transcription factor, early growth response-1 (Egr-1), as highly upregulated downstream of EGFR signaling. When TGF-α transgenic mice were crossed to Egr-1 knockout mice, adults developed more severe lung remodeling, including extensive airway smooth muscle (ASM) thickening and more severe pulmonary fibrosis. This phenotype developed in the absence of inflammation, and lung mechanics studies showed that loss of Egr-1 also caused severe airway hyperresponsiveness (AHR) to methacholine. Since airway remodeling and AHR are key characteristics of asthma, we investigated the role of EGFR in a mouse model of asthma induced by chronic house dust mite (HDM) inhalation. Blockade of the EGFR in HDM treated mice, us (open full item for complete abstract)

Committee: Timothy Le Cras PhD (Advisor); Thomas Korfhagen MD, PhD (Committee Member); James Lessard PhD (Committee Member); John Shannon PhD (Committee Member); Jeffrey Whitsett MD (Committee Member); Kathryn Wikenheiser-Brokamp MD, PhD (Committee Member) Subjects: Biology

PhD, University of Cincinnati, 2024, Pharmacy: Pharmaceutical Sciences

Traumatic Brain Injury (TBI) is a primary cause of disability and death within the United States of America. In the clinic, TBI presents as extraordinarily heterogenous pathologies given that brain injuries may be induced by a plethora of diverse and deleterious environmental interactions including but not limited to penetrating head injuries, acceleration-deceleration inertial forces acting upon the parenchyma of the brain, and exposure to blast waves. In civilian populations, it is thought that the reporting of TBIs, particularly mild TBIs (mTBI) or concussions, is significantly lower than the true prevalence in the population at large. Although the pathologies associated with each TBI are often distinct between cases and vary between individuals, sustaining a TBI significantly and unilaterally increases the risk for developing chronic emotional, social, and psychological complications regardless of injury modality which represents a critical factor in determining quality of life for those afflicted. The prevalence of psychosocial abnormalities includes an increased risk for developing major depressive disorder (MDD), anxiety disorders like generalized anxiety disorder (GAD) and panic disorders, as well as post-traumatic stress disorder (PTSD) is greatly increased in individuals who have sustained neurotrauma. Decades of research have linked the monoamine neurotransmitter serotonin (5HT) and the central serotonin system to the development and maintenance of mood, memory, and perception and have localized the nexus of serotonergic signaling to a midbrain structure called the raphe nucleus (RN). While the United States Food and Drug Administration (FDA) -approved pharmacotherapies for the treatment of disorders like anxiety and depression, selective serotonin reuptake inhibitors (SSRIs), are moderately efficacious in attenuating non-injury elicited psychopathologies, the application of these drugs in the context of TBI does not significantly improve patient outcomes (open full item for complete abstract)

Committee: Matthew Robson Ph.D. (Committee Chair); Gary Gudelsky Ph.D. (Committee Member); Jason Gardner (Committee Member); Nathan Evanson M.D. Ph (Committee Member); Timothy Phoenix Ph.D. (Committee Member) Subjects: Pharmaceuticals

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

Synaptic circuitry is sculpted by glia. We sought to develop the Drosophila antennal lobe as a new model for identifying conserved principles underlying synapse-glia interactions. Antennal lobe organization is highly stereotyped and characterized by individual glomeruli comprised of unique olfactory receptor neuronal (ORN) populations. The antennal lobe interacts extensively with two glial subtypes. Ensheathing glia wrap individual glomeruli, while astrocytes ramify considerably within them. Roles for ensheathing glia and astrocytes in phagocytosis of terminal arbors and synapses in the uninjured antennal lobes are undefined. Thus, we tested whether Draper is required in either glial subtype to regulate ORN terminal arbor size, shape, or presynaptic content in two representative glomeruli: VC1 and VM7. We find that glial Draper limits the size of individual glomeruli and restrains their presynaptic content. Moreover, glial refinement of ORN terminals is apparent in young adults, a period of rapid terminal arbor and synapse growth, indicating that synapse addition and elimination occur simultaneously in this circuit. Surprisingly, Draper plays differential roles in ensheathing glia and astrocytes in VC1 and VM7, arguing for local heterogeneity of neuron-glia interactions. We also tested whether Draper is required for activity-dependent remodeling of VM7. We find that glial Draper is required for the shrinkage of ORN arbors projecting to VM7 that occurs in response to ethyl butyrate (EB) exposure during early adulthood. Finally, we recorded spontaneous activity of projection neurons (PNs) downstream of VC1 and VM7 ORNs in animals with glial subtype-specific Draper loss. Either astrocytic or ensheathing glial knockdown of Draper leads to a dramatic increase in spontaneous activity and a reduction in processing performance of PNs demonstrating functional consequences to Draper loss. Together, these data demonstrate that the phagocytic activities of distinct glial (open full item for complete abstract)

Committee: Heather Broihier Ph.D. (Advisor); Pola Philippidou Ph.D. (Committee Chair); Masashi Tabuchi Ph.D. (Committee Member); Catherine Collins Ph.D. (Committee Member); Helen Miranda Ph.D. (Committee Member); Andrew Pieper M.D., Ph.D. (Committee Member) Subjects: Neurobiology; Neurosciences

Doctor of Philosophy, The Ohio State University, 2023, Mechanical Engineering

Finite element method (FEM) is a numerical method that is widely used for obtaining approximate solutions to various engineering and research problems. In material science, FEM is used to simulate the mechanical response of materials under dierent loadings and to guide the design of materials with targeted properties. Generating high-delity nite element (FE) models of materials with complex microstructures, such as composite materials, requires generating realistic virtual microstructures of materials that are statistically equivalent to the actual microstructure and converting them to high-delity FE meshes. Choosing appropriate mechanical models and material properties for materials is also a fundamental challenge to obtaining an accurate simulation result. In this thesis, advanced computational frameworks are introduced to overcome these challenges, including creating realistic virtual microstructures of materials by algorithm, developing new damage models, and applying articial intelligence (AI) techniques to the model of materials with complex microstructures. Several numerical techniques are presented to model materials and analyze their micromechanical behaviors. Two new high-cycle fatigue damage models are introduced for modeling mechanical performance under cyclic loading to predict the fatigue life of heterogeneous adhesives, one for the matrix and the other for the particle-matrix interfaces. An automated computational framework is developed to simulate the performance of adhesives under cyclic loading. High-delity nite element models of this adhesive's representative volume elements (RVEs) are generated using an automated computational framework, enabling the virtual reconstruction of the microstructure and mesh generation. These 3D FE models are used to calibrate the fatigue damage model parameters with fatigue test data under dierent loading conditions. Another example presents a high-delity FE model, constructed based on (open full item for complete abstract)

Committee: Soheil Soghrati (Advisor); William Marras (Committee Member); Alok Sutradhar (Committee Member) Subjects: Mechanical Engineering

Doctor of Philosophy (PhD), Ohio University, 2022, Biological Sciences (Arts and Sciences)

The mammalian vasculature caters to tissue specific gaseous exchange and metabolic needs. The brain accounts for the largest consumption of oxygen and glucose, for which a structurally organized and functional cerebrovasculature is essential. Brain arteriovenous malformations (BAVM) are characterized by abnormally enlarged blood vessels, which direct blood through arteriovenous (AV) shunts, bypassing the normal artery-capillary-vein network. High-pressure, low-resistance AV shunts disrupt healthy blood flow and can result in cerebrovascular hemorrhage. BAVM is the leading cause of intracerebral hemorrhage in children, and accounts for 50% of stroke incidences in children and young adults. Clinically, BAVM treatments are invasive and not applicable to all cases; thus, there is critical need to understand BAVM mechanisms and develop targeted therapeutics. Using a mouse model of BAVM, that is deficient in Notch effector Rbpj from endothelial cells, from birth – we show that isolated Rbpj-deficient (RbpjiΔEC) brain endothelial cells (BECs) elicit altered whole-genome transcriptomic profile, early at Postanal day (P)7 when expansion of AV diameters – the most prominent BAVM phenotype is not observed, suggesting contribution of Rbpj regulated effector molecules in triggering onset of BAVM pathogenesis. Cellular studies over the course of characterized developmental time-periods at P7, P10, and P14 revealed that AV expansion in RbpjiΔEC mice do not originate from hyperplastic or hypertrophic mechanisms; but RbpjiΔEC BECs acquired atypical morphology and increased BEC density along AV shunts, as compared to controls, in postnatal mice. RbpjiΔEC mice also showed reduced regression of BECs over AV connections when studied through empty basement membrane collagen sleeve (EBMS) dynamics, suggesting lack of remodeling and accumulation of BECs over capillary like vessels in vivo. Using isolated postnatal mouse BECs, we found altered small GTPase activity in (open full item for complete abstract)

Committee: Corinne Nielsen (Advisor); Mark Berryman (Committee Member); Fabian Benencia (Committee Chair); Monica Burdick (Committee Co-Chair); Soichi Tanda (Committee Member) Subjects: Biochemistry; Cellular Biology; Genetics; Molecular Biology

Doctor of Philosophy, The Ohio State University, 2021, Biomedical Sciences

Heart disease is a leading cause of morbidity and mortality in the United States. Cardiac remodeling is a universal facet of heart disease, and occurs in predictable patterns in response to stress stimuli. Although stress-induced remodeling is a multifaceted and complex process, two major components of remodeling include cardiomyocyte hypertrophy and myocardial fibrosis. Although many cell types within the heart contribute to cardiac remodeling, cardiomyocytes are often considered the effectors of cardiac hypertrophy, which over time leads to decreased cardiac function and symptomatic heart failure. Although the physical and genetic changes associated with cardiomyocyte hypertrophy itself are predictable and well documented, the precise mechanisms by which certain stimuli may cause these changes are exceedingly complex. In this dissertation I demonstrate how two separate processes, extracellular matrix-resident protein interactions and the small chemical mRNA modification m6A, can induce cardiomyocyte remodeling and may be manipulated to understand how a cardiomyocyte responds to external stressors. First, I examine the role of connective tissue growth factor (CTGF or CCN2) in the pathogenesis of stress-induced myocardial fibrotic remodeling. By using cell-specific genetic knockdown of CCN2 in mouse models, I determined that cardiomyocyte-derived CCN2 is dispensable for angiotensin II- or TGFb1- induced fibrosis; in contrast, fibroblast-derived CCN2 is essential for myofibroblast transdifferentiation and fibrotic remodeling in vivo. I next investigate the contribution of microfibrillar-associated protein 4 (MFAP4) in the pathogenesis of cardiomyocyte hypertrophy. MFAP4 is a TGFb1-inducible extracellular matrix protein that is upregulated in the heart in response to cardiac stress and is highly expressed by nonmyocytes but not cardiomyocytes. Using an MFAP4 knockout mouse model, I determine that the loss of MFAP4 leads to exacerbated cardiomyocyte hypertr (open full item for complete abstract)

Committee: Federica Accornero PhD (Advisor); Paul Janssen PhD (Advisor); Ray Hershberger MD (Committee Member); Kalpana Ghoshal PhD (Committee Member) Subjects: Biomedical Research; Cellular Biology; Molecular Biology; Physiology

Doctor of Philosophy, University of Akron, 2019, Biomedical Engineering

Bisphosphonate-related osteonecrosis of the jaw (BRONJ) is an elusive disease that presents as exposed necrotic bone following tooth extraction. It occurs in patients undergoing bisphosphonate therapy for metastasizing cancers and osteoporosis. Experts believe the condition is caused by a defect in bone remodeling, the process by which osteoclasts resorb bone and osteoblasts form new bone, within the oral cavity. Its complexity requires a multicellular model to address the net effects of two key risk factors: tooth extraction (overload) and inflammation associated with bacterial infection. In this work, a system comprised of a deformable polymeric chip and mechanical loading device is used to expose bisphosphonate-treated osteocytes, the mechanosensing bone cells, to overload. Osteocyte viability is evaluated as a function of load, and soluble activity is assessed. Effects of these factors on bone resorption by osteoclasts and bone formation by osteoblasts are quantified. Osteoclast activity is also quantified in the presence of inflammatory agents, lipopolysaccharide and interferon gamma. Results support a role for osteocyte mechanotransduction in suppressing osteoblast bone formation within a BRONJ environment. They also suggest inflammation may inhibit resorption of necrotic bone by osteoclasts. These findings provide insights into BRONJ that may contribute to its elucidation. This dissertation also lays the foundation for a biomimetic lab-on-a-chip platform for the study of bone turnover and remodeling-related disease. Fabrication techniques are developed, and osteocyte, osteoclast and osteoblast characterizations are performed on relevant substrates within microfluidic devices. Culture conditions, including seeding densities, feeding requirements and time points for analyses are determined. This work will enable the development of a controlled multicellular lab-on-a-chip capable of quantifying the aggregate response of bone cells to disease cofactors.

Committee: Marnie Saunders PhD (Advisor); Hossein Tavana PhD (Committee Member); Ge Zhang PhD (Committee Member); Jiang Zhe PhD (Committee Member); Sailaja Paruchuri PhD (Committee Member) Subjects: Biomedical Engineering

PHD, Kent State University, 2018, College of Arts and Sciences / School of Biomedical Sciences

ABSTRACT Ischemic heart disease (IHD) is the major underlying cause of myocardial infarction (MI), scarring, and hypertrophy leading to heart failure which is one of the leading causes of death. Cardiac remodeling following induced pressure overload/myocardial infarction is a multiphase reparative process which involves replacement of damaged tissue with physiological (reparative) fibrosis to form scar that limit the expansion of the left ventricle/infarct of the heart. Although therapeutic approaches targeting soluble factor (ex: ACE inhibitors, ARBs, TGF-ß inhibitors: Pirfenidone, Halofuginone) signaling is available for the treatment of cardiac fibrosis and hypertrophy, they showed modest efficacy in clinics. Hence, it is indispensable to identify and develop an alternate and novel therapeutics to treat the heart failure. Mechanical cues are indeed necessary to integrate with soluble factor associated signaling to maintain cardiac physiological functions. Of late, TRPV4 has been shown to be mechanosensor and our lab has established that TRPV4 is a key mechanosensor in endothelial cells and cardiac fibroblasts (CF) and plays an important role in cardiovascular pathophysiology. We have recently demonstrated that TRPV4 mediates cardiac fibroblast differentiation into myofibroblasts in vitro. However, the physiological significance of TRPV4 in cardiac remodeling in vivo is not known. Based on our previous findings, we hypothesized that targeting TRPV4 may offer cardioprotection following pressure overload-induced hypertrophy and myocardial infarction. The first aim of the dissertation was to determine whether TRPV4 mediated mechanotransduction preserves the heart integrity and reduce fibrosis in vivo following pressure overload-induced hypertrophy. By inducing pressure overload hypertrophy (TAC), we found that TRPV4 knockout (KO) mice exhibited improved cardia function, decreased myocardial cross sectional area and left ventricular mass when compared with WT. Furt (open full item for complete abstract)

Committee: CHARLES THODETI PH.D. (Advisor); WILLIAM CHILIAN PH.D (Committee Member); LIYA YIN PH.D (Committee Member); MOSES OYEWUMI PH.D (Committee Member); GARY KOSKI PH.D (Committee Member) Subjects: Biology; Biomedical Research

MS, University of Cincinnati, 2017, Engineering and Applied Science: Aerospace Engineering

To better understand skull response after surgeries in patients born with an alveolar cleft, a finite element method (FEM) has been designed to predict how bone is strained during normal loading cycles of mastication. To test the effectiveness of treatment utilizing stem cells on resorbable scaffolds, a juvenile swine was operated by a surgically created alveolar cleft. Then, the FEM model of the pig skull was built based from pre- and post-surgery computed tomography (CT) to estimate strain dynamics in the healing bone. Scan resolutions were insufficient to visualize bone at the scale of trabeculae, a necessary item to determine how depositional fields in healing and growing bone will respond to loading. This is important because bone deposition is sensitive to both strain and material properties of depositional substrates. Hence, a detailed model is urgently needed with more accurate skull structure and mechanical properties. In this thesis, a new semi-automated method is proposed to build a more accurate skull model with microCT (µCT) scans. In addition to applying the new model in alveolar cleft repair, this new method can also be used to estimate remodeling algorithms incorporated with three dimensional (3D) finite element methods (FEM) script. In this way, finite element method (FEM) can been used to predict how mature bone partially remodels under mechanical loadings.

Committee: Gui-Rong Liu Ph.D. (Committee Chair); Yao Fu (Committee Member); Donna Jones Ph.D. (Committee Member) Subjects: Biomechanics

PhD, University of Cincinnati, 2017, Medicine: Molecular, Cellular and Biochemical Pharmacology

Heart failure, the final clinical manifestation of numerous cardiovascular maladies, is a devastating disease characterized by interstitial fibrosis, chamber remodeling and reduced ventricular compliance. Elevated myocardial sympathetic stimulation, a hallmark of heart failure, induces pathological signaling through G protein βγ subunits that results in the activation and membrane recruitment of G protein-coupled receptor kinase 2 (GRK2). In the failing heart, diminished cardiac output triggers a vicious cycle of persistent sympathetic stimulation accompanied by perpetual maladaptive signaling due in large part to GRK2-mediated β-adrenergic receptor desensitization and loss of responsiveness. We recently identified and validated the novel small molecule inhibitor gallein that disrupts the Gβγ-GRK2 interaction. Here, we investigated the therapeutic potential of gallein in murine ischemia-reperfusion (I/R) injury, a clinically relevant model of ischemic heart failure. We found that pharmacological disruption of Gβγ-GRK2 signaling post-I/R offered significant protection against cardiac dysfunction and remodeling. Moreover, we observed that gallein treatment significantly ameliorated fibrotic infarct expansion and the expression of several pro-fibrotic markers, which likely contributed to the overall improvement in ventricular contractility. One principal objective was to decipher the cellular specificity of gallein by ablating GRK2 in various resident cell populations of the heart. While the salutary properties of cardiomyocyte-specific ablation of GRK2 have been extensively documented, our goal was to explore the potential cardiomyocyte-independent cardioprotective properties of gallein. While GRK2 ablation in cardiomyocytes offered modest protection against cardiac dysfunction and remodeling, it was only with concurrent gallein treatment that significant cardioprotection was achieved. These findings suggested functional significance for Gβγ-GRK2 inhibition in c (open full item for complete abstract)

Committee: Burns Blaxall Ph.D. (Committee Chair); Evangelia Kranias Ph.D. (Committee Member); William Miller Ph.D. (Committee Member); Jeff Molkentin Ph.D. (Committee Member); Jo El Schultz Ph.D. (Committee Member) Subjects: Pharmacology

Bachelor of Science (BS), Ohio University, 2017, Biological Sciences

Osteoporosis is a disease characterized by diminished bone strength, resulting in an increased risk for fracture with minimal trauma. Though osteoporotic fractures present severe consequences for patients and health communities alike, there remains to be an accurate diagnosis for this disease. There are many characteristics that influence bone strength, ranging from mechanical, microstructural, to geometrical in nature. This project specifically aimed to assess cortical porosity, diameter, and bending stiffness as predictors of bending strength in the human radius. Data was collected from thirty cadaveric human radii from men and women between the ages of 17-99 years. Bending strength and bending stiffness were measured by the gold standard three-point bending method, quasi-static mechanical testing (QMT). Interosseous diameter was measured from both higher resolution µCT and lower resolution CT scans. Finally, cortical porosity was measured from µCT scans in the NIH image-processing software ImageJ. These measurements were guided by 3D Avizo models. Simple linear regression analyses revealed that bending stiffness predicted bending strength with the least amount of uncertainty (SEE=3.2 Nm). Cortical porosity demonstrated the weakest relationship with bending strength (SEE=12.0 Nm). Predictions of bending strength by µCT diameter were not different from those made by CT diameter (p=0.37). In comparisons of cortical porosity in the radius and ulna as imaged from the same arms, porosity at the 55%L of the ulna was the only unbiased predictor of radius porosity adjacent to the QMT fracture site (p=0.12). Thus, at the midshaft, cortical porosity of the ulna and radius appear to be indistinguishable.

Committee: Anne B Loucks PhD (Advisor) Subjects: Anatomy and Physiology; Biology; Cellular Biology; Endocrinology; Kinesiology; Medical Imaging; Molecular Biology; Morphology; Physiology

Doctor of Philosophy, Case Western Reserve University, 2017, Biomedical Engineering

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia. Postoperative AF (POAF), a specific form of AF, is the most common complication after cardiac surgery. Current therapies are suboptimal with a limited efficacy and significant toxicity, suggesting the need to develop novel and more effective therapies. Gene therapy becomes an attractive alternative to prevent or ablate AF. AF is considered to be sustained by reentrant mechanisms that are promoted by atrial remodeling. We studied the two major forms of atrial remodeling: structural and electrical remodeling. Calcium/calmodulin-dependent protein kinase II (CaMKII) plays a role in structural remodeling in several tissues, but its role in sustaining AF remains undefined. We tested the hypothesis that increased CaMKII activity is a cause of structural remodeling in AF. We assessed the effects of CaMKII inhibition in our porcine AF-heart failure model after atrial gene transfer with an adenovirus encoding a potent and specific inhibitor of CaMKII (the inhibitory peptide CaMKIIn). Inhibition of CaMKII preserved atrial contractile function and attenuated atrial structural remodeling, including hypertrophy, fibrosis and apoptosis but did not affect inflammation or myolysis. These observations were accompanied by significantly decreased phosphorylation of HDAC4 and decreased expression of p38MAP-Kinase, but no change in JNK or ERK1/2. Action potential duration (APD) shortening is an important aspect of electrical remodeling. Our previous work showed that KCNH2-G628S gene therapy eliminated AF by prolonging APD. In this study, we examined the efficacy and safety of KCNH2-G628S gene therapy to prevent POAF. We found that the gene transfer reduced AF burden without any evident toxicity in extensive safety analysis. The timing of adenovirus-mediated gene expression is such that the method can be directly applicable to prevent POAF, which supports further study in a Phase I clinical trial. Furtherm (open full item for complete abstract)

Committee: J. Kevin Donahue (Advisor); Andrew Rollins (Committee Chair); Xin Yu (Committee Member); Kenneth Laurita (Committee Member); David Van Wagoner (Committee Member) Subjects: Biomedical Engineering

Doctor of Philosophy, The Ohio State University, 2016, Materials Science and Engineering

Myocardial infarction usually occurs after the blockage of coronary arteries. Cardiac cells are immediately exposed to a harsh environment with insufficient oxygen and nutrients. With prolonged hypoxia, the cardiomyocytes are damaged, which triggers the cardiac pathological hypertrophy, leading to the loss of heart function. Meanwhile, the cytokines are upregulated within myocardium may have negative effects in keeping the ventricular geometry. The level of transforming growth factor beta (TGFß) is increased which would drive the cardiac fibroblast differentiation into cardiac myofibroblast by activating the TGFß/ Smad signaling pathway to achieve wound healing process. However, the excessive collagen produced by myofibroblast is responsible for cardiac fibrosis. Myocardial extracellular matrix (ECM) degradation may also occur, due to the elevated matrix metalloproteinase -2 (MMP-2) concentration. The impairment of ECM may lead to wall thinning, further causing myocardial remodeling. To control cardiac fibrosis, downregulation of the TGFß signaling pathway by blocking the TGFß receptor II (TGFßRII) would be necessary. To reduce wall-thinning induced myocardial remodeling, MMP-2 activity needs to be inhibited. Small molecule based TGFßRII and MMP-2 inhibitors are widely used in current studies, but their off-target binding leads to toxicity, which largely limits their clinical use. Thermosensitive hydrogel based localized drug delivery system is attractive in heart injection for the high drug retention at the infarcted site. The drug encapsulated in the hydrogel could be released for a long period of time. In this dissertation, a MMP-2 inhibitor peptide (CTT) and a TGFßRII binding peptide (ECG) were explored and encapsulated in the hydrogel to develop drug delivery system. Both peptides could release at least 28days, and showed bioactivity. In an animal MI model, the ECM could be preserved by injecting CTT delivery system; a significant reduction of m (open full item for complete abstract)

Committee: Jianjun Guan (Advisor); Peter Anderson (Committee Member); John Lannutti (Committee Member) Subjects: Biomedical Engineering; Materials Science

Doctor of Philosophy, The Ohio State University, 2016, Biomedical Engineering

Volume overload (VO) induced heart failure results from an increase in blood volume (preload) to the heart. The heart responds to increases in hemodynamic load through compensative remodeling. VO has a distinct pattern of remodeling compared to pressure overload induced heart failure, which results in fibrosis. VO results in a net decrease in extracellular matrix (ECM). This loss of ECM contributes to the progression of the disease due to the loss of structural integrity. Since cardiac fibroblasts (CFs) are the main cells responsible for maintaining ECM in the heart, we characterized the in vitro phenotype of CFs isolated from a rat VO model, aortocaval fistula (ACF). Compared to sham operated animals, ACF fibroblasts displayed a phenotype that we described as “hypofibrotic”. ACF CFs secreted relatively less collagen and profibrotic molecules, such as a-smooth muscle actin (aSMA) and connective tissue growth factor (CTGF). Interestingly, ACFs produce approximately twice as much transforming growth factor-ß1 (TGF-ß), a key profibrotic stimulus, as their sham counterparts. However, there were no changes in the canonical TGF-ß pathway that could account for the hypofibrotic phenotype observed in ACF fibroblasts. Since others have shown that the cytoskeleton and the Rho/ROCK pathway play a role in fibroblast phenotype, we characterized the actin cytoskeleton in sham and ACF fibroblasts. We found that ACF CFs have significantly less F-actin than sham CFs. We were able to show that it is possible the actin cytoskeleton might account for phenotypic differences in CFs by chemically altering the amounts of F-actin and G-actin. When the cells were treated with a ROCK inhibitor, which allows F-actin to depolymerize into G-actin, CFs displayed a more hypofibrotic phenotype. Conversely, enhancement of F-actin with jasplakinolide treatment forced the CFs to have a profibrotic phenotype. Numerous studies have linked substrate modulus with effects on the cytoskeleton. S (open full item for complete abstract)

Committee: Keith Gooch PhD (Advisor); Jun Liu PhD (Committee Member); Pamela Lucchesi PhD (Committee Member); Aaron Trask PhD (Committee Member) Subjects: Biomedical Engineering

Master of Science (MS), Wright State University, 2015, Biochemistry and Molecular Biology

The best characterized eukaryote replication model is of the budding yeast Saccharomyces cerevisiae. Replication origins of S.cerevisiae are 100 to 200 bp in size and contain an essential 11-bp autonomous replicating sequence (ARS) consensus sequence (ACS). The origin recognition complex (ORC) binds to the ACS in order to recruit additional replication factors (Cdt1, Cdc6, MCM, Cdc45) and together they form the pre-replication complex (pre-RC). Unlike budding yeast, the mammalian cells contain dispersed replication origins in which multiple elements distributed over large distances act as replication start sites. Mammalian DNA replication origins, such as the c-myc origin, contain a DNA unwinding element (DUE), which is an AT-rich region that contains10-of-11 matches to ARS consensus. Our lab primarily studies DNA replication of the human c-myc locus. We have successfully integrated the wild-type 2.4 kb c-myc replication origin and its various inactive mutants in a known ectopic chromosomal site in HeLa/406 cells in order to study the multiple functional elements of this origin. My thesis focused on investigating the minimal sequence required in mammalian replication origin for replication activity. To address this question, I assessed the effects of replication protein tethering on chromatin accessibility of inactivated c-myc origins which are 930 bp or less and contain an intact DUE. In part I of my thesis, I describe how I made two new HeLa/406 cell lines containing two different deletion mutants of the cmyc replicator core (which are 607 bp and 228 bp long) at the known ectopic chromosomal site. In part II of my thesis, I describe how I created plasmids expressing GAL4 DNA-binding domain (GAL4DBD)-BRG1 fusion proteins. BRG1 is a catalytic core subunit of SWI/SNF mammalian chromatin remodeling complex. Wild-type BRG1 and catalytic inactive BRG1K798R mutant were used to make GAL4DBD fusion proteins. In part III of my thesis, I evaluated the effects of (open full item for complete abstract)

Committee: Michael Leffak Ph.D (Advisor); Weiwen Long Ph.D (Committee Member); John Paietta Ph.D (Committee Member) Subjects: Molecular Biology

Doctor of Philosophy, The Ohio State University, 2015, Comparative and Veterinary Medicine

Cathepsin K (CatK), a cysteine protease, has been implicated in the process of bone resorption and inflammation. Selective inhibitors of CatK are promising therapeutic agents for the treatment of diseases associated with excessive bone loss and osseous inflammation, such as osteoarthritis, rheumatoid arthritis, periodontitis, osteoporosis, and multiple myeloma. Multiple reports have emerged over the last several years demonstrating the effect of different CatK inhibitors on osteo-inflammatory conditions. Therefore, the study of CatK inhibition as a target to prevent bone loss and inflammation, and influence bone marrow osseous progenitor cells, in a large animal model, is the subject of this dissertation. The horse was selected as the large animal model because this species suffers from ailments of adaptive bone remodeling in their sport performance and CatK inhibitors may serve as therapeutics in this species as well as serve as a large animal model for human applications. In the first phase of this work, we determined an optimal dose and dose interval for a CatK inhibitor (CatKI), VEL-0230, in healthy adult horses. Plasma pharmacokinetic (PK) and bone resorption biomarker [carboxy-terminal cross-linking telopeptide of type I collagen (CTX-1)] analyses were performed following single and multiple oral dose protocols of a CatKI (VEL-0230) in horses. Weekly administration of VEL-0230, at a dose of 4 mg/ kg body weight, provided effective inhibition of bone resorption in young exercising horses that returned to baseline within 7 days after drug withdrawal even after multiple doses. In the second phase of this work, we evaluated bone structure and turnover in healthy young exercising horses receiving repeated oral dosing of a CatKI in a randomized, controlled, double-blinded, prospective, sufficiently powered clinical trial. With the objectives of: 1. To determine whether repeated dosing of a CatKI produced a desired inhibition of the bone resorption biomarker (open full item for complete abstract)

Committee: Alicia Bertone PhD (Advisor); Maxey Wellman PhD (Committee Member); Prosper Boyaka PhD (Committee Member); Teresa Burns PhD (Committee Member) Subjects: Biology; Biomedical Research; Cellular Biology

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

Doctor of Philosophy, The Ohio State University, 2014, Biomedical Engineering

Active, mechanical interactions between cells and their extracellular matrix (ECM) are essential for ECM remodeling and cell migration, two behaviors that support diverse biological processes including embryonic development, wound healing, fibrosis, and cancer progression. Cell-populated reconstituted type I collagen hydrogels are often used as a model system in which to study ECM remodeling and cell migration in vitro. Unfortunately, this system has limitations since it is not possible to independently control individual microstructural properties. This limitation has inspired theoretical models as an alternative way to study ECM remodeling and migration. However, so far no single approach has been able to capture both fibril-level detail and dynamic cell traction force. With the goal of creating a model that can capture both fibril-level detail and dynamic cell traction force, we developed an agent-based model of cell-mediated collagen compaction and migration. With this model we observed behaviors that were not programmed, but emerged from simple rules for cell-fibril interactions. Among these, our model qualitatively reproduced remodeling commonly seen in cell-populated collagen gels: macroscopic, pericellular, and intercellular compaction. Similar to experimental observations, matrical tracks formed between pairs of cells before directional migration of nearby cells toward on another. Cells also exhibited durotaxis in the absence of force-strengthening of cell-matrix bonds. This suggests that durotaxis may not involve a complicated mechanism, but may simply be an emergent behavior, the cumulative result of analogous, simple, cell-matrix interactions. We then further developed this model to make collagen fibrils more physically-realistic by modeling them as elastic rods and using parameter values obtained from the experimental literature. Subjecting our fibrils to loading conditions that created tension and bending demonstrated that our simulated fibrils app (open full item for complete abstract)

Committee: Keith Gooch (Advisor); Samir Ghadiali (Committee Member); Richard Hart (Committee Member); Peter Anderson (Committee Member) Subjects: Biomedical Engineering

Master of Arts, The Ohio State University, 2014, Anthropology

Within human populations, differences in bone mass may be attributed to variation in environmental factors such as diet, health, and physical activity. Relative cortical area (RCA) and the parabolic index (PI) both quantify bone mass by calculating the percentage of a cross-section of bone occupied by the solid region of the cortex. Yet the cortex is not solid, being perforated with numerous vascular channels and resorptive spaces. By subtracting these porous voids from cortical area, anthropologists can avoid overestimations of bone mass that distort inferences about physical activity and health. This study presents a semi-automated protocol for quantifying the porosity of a cortex using brightfield microscopy. The protocol automatically differentiates between cortical pores and resorption bays that have coalesced to become “trabecularized” at the endosteal border. This expedited method does not produce significantly different values than those obtained by manually measuring each pore, as tested on a sample of eleven ribs (p = 0.532). Correction for cortical and total porosity significantly reduced values of RCA and PI in femora, tibiae, and ribs of nine individuals. Within single individuals, the rib had significantly greater trabecularized porosity than the femur (p < 0.0009) or tibia (p = 0.004). This trabecularization was localized to the cutaneous cortex of the rib (p = 0.011). Cyclical tension of this cortex during respiration may produce the mechanical loading and microdamage that drives this resorption bay coalescence at the endosteal border.

Committee: Samuel Stout Dr. (Advisor); Clark Larsen Dr. (Committee Member); Douglas Crews Dr. (Committee Member); Amanda Agnew Dr. (Committee Member) Subjects: Physical Anthropology

Master of Science, Miami University, 2013, Zoology

During Drosophila development, remodeling of the larval nervous system is necessary for adult specific behavior. During metamorphosis abdominal peripheral nerves fuse to form a terminal nerve trunk (TNT). We propose that glial cells are required for this fusion to occur. Here, four glial layers that ensheath Drosophila peripheral nerves are analyzed. The inner most layer, wrapping glia, and outermost layer, neural lamella, are not present during TNT formation, while the perineurial and subperineurial glial layers persist. Glial cells increases 3 fold during early pupation and ~75% of these glia are perineurial glia. Induction of perineurial glial cell death via the cell death gene reaper, resulted in abnormal TNT formation, suggesting that perineurial glial cells play a role in the fusion process. The characterization of Drosophila glial layers during development will allow for future functional studies and could lead to a model system used to study gliopathies.

Committee: Joyce Fernandes (Advisor); Lori Isaacson (Committee Member); Kathleen Killian (Committee Member) Subjects: Zoology