PhD, University of Cincinnati, 2018, Medicine: Pathobiology and Molecular Medicine

Dendritic cells (DCs) are the most efficient antigen presentation cells and execute a pivotal role in the onset and regulation of innate and adaptive immune responses and the recruitment of a variety of leukocytes to the site of inflammation or injury. To counter the challenge of the non-stop exposure to exogenous pathogens, the lungs developed an intrigue and complex immunology defense orchestra that conducted by DCs. An increasing volume of research on DCs in recent years show that the disruption of DC equilibrium in the lung may result in different diseases. In this study, we used two different disease models to elucidate the importance of DC in disease pathogenesis. Pulmonary Langerhans cell histiocytosis (PLCH) is a rare interstitial lung disease characterized by focal DC accumulation, bronchiolocentric nodule formation, and cystic remodeling of the lung and occurs predominantly in active smokers. Approximately 50% of PLCH patients harbor somatic BRAF-V600E mutations identified mainly within the DC lineage. However, the rare nature of the disease and lack of animal models impedes the study of the pathogenic mechanisms of PLCH. We have established the first mouse model that recapitulates the hallmark characteristics of PLCH. In addition, we show that the BRAF-V600E mutation is associated with increased DC responsiveness towards multiple stimuli including the DC-chemokine CCL20. We provide evidence that DC accumulation in the lung is due to both increased viability and enhanced recruitment. Further evidence indicates that the accumulation of other inflammatory cells in PLCH is a secondary event driven by CCL7 secreted from DCs in a BRAF-V600E-dependent manner. Moreover, we demonstrate that the PLCH-like phenotype in the mouse model can be attenuated following smoking cessation and removal of BRAF-V600E DCs. Furthermore, we show PBMCs isolated from PLCH patients harboring the BRAF-V600E mutation produce CCL7. Collectively, our studies provide the first mechani (open full item for complete abstract)

Committee: Michael Borchers Ph.D. (Committee Chair); Ian Paul Lewkowich Ph.D. (Committee Member); Francis McCormack M.D. (Committee Member); William Miller Ph.D. (Committee Member); Kathryn Wikenheiser-Brokamp M.D. Ph.D. (Committee Member) Subjects: Surgery

Doctor of Philosophy, The Ohio State University, 2018, Oral Biology

The oral cavity is an open ecosystem with niche-specific microbial colonization. Within a few hours after birth, bacteria colonize the oral cavity and form complex communities called biofilms. These biofilms constantly interact with the host immune system and play an important role in the maintenance of health. Dysbiotic bacterial communities are established as the underlying etiology of periodontitis, a disease that destroys structures tooth-supporting structures and results in tooth loss. Several factors are known to contribute to an individual's susceptibility to periodontitis, notably, smoking and diabetes, however, the mechanisms by which they increase the risk for this bacterially induced inflammatory disease have not been well established. The purpose of this investigation was to examine the relative contributions of smoking and diabetes to shaping the subgingival microbiome. Cross-sectional and longitudinal cohort study designs using were combined with comprehensive systems biology approach to characterize the composition, functional characteristics, gene-expression patterns, and structure of the oral microbial ecosystem in response to these perturbations both in periodontal health and disease. In vitro models were used to validate the clinical findings and to explore a biological basis for the shifts. Smoking, diabetes, and e-cigarettes selectively enriched for disease-associated species and specific virulence functions in this ecosystem even in states of clinical health. Each of these perturbations exerted a unique effect on the microbiome, in terms of species composition, biofilm architecture and functional potential, thus enabling us to identify and validate microbial biomarkers unique to each perturbation. Finally, we investigated whether the associations between bacterial virulence and smoking was causal or casual by examining the responses of the subgingival microbiome to smoking cessation. Quitters demonstrated a significant shift in microbial compos (open full item for complete abstract)

Committee: Purnima Kumar (Advisor); Haikaday Nagaraja (Committee Member); John Walters (Committee Member); Kelly Wrighton (Committee Member); Benjamin O'Donnell (Committee Member) Subjects: Dentistry; Ecology; Epidemiology; Microbiology; Molecular Biology

Doctor of Philosophy, The Ohio State University, 2014, Integrated Biomedical Science Graduate Program

Chronic obstructive pulmonary disease (COPD) is a complex respiratory disease primarily caused by cigarette smoking. Cadmium (Cd), a toxic metal abundantly present in cigarette smoke, has been implicated in the development of disease, and accumulates in the bodies of smokers. It was recently discovered that a zinc (Zn) transporter, SLC39A8 (ZIP8), is responsible for the primary import of Cd into cells. Our lab discovered ZIP8 is under the transcriptional regulation of the central inflammatory NF-kappaB pathway. We hypothesize that inflammation in the lung created by smoke exposure increases the expression of ZIP8 thereby facilitating Cd uptake and pathology associated with COPD. The first aim of our work addressed the role of ZIP8 in Cd-mediated epithelial cell toxicity using the adenocarcinomic alveolar epithelial A549 cell line. Cd-induced toxicity was enhanced by TNF-alpha in an NF-kappaB-dependent manner, which stimulated expression of ZIP8. Use of an NF-kappaB (p65) inhibitor (Bay11-7082) or ZIP8 siRNA resulted in a significant decrease in cell toxicity. Cell death was also reversible with increasing concentrations of the micronutrient Zn. Immunohistochemical analysis of primary human upper airway epithelial cells revealed preferential ZIP8 expression on the environmentally-facing apical membrane. Analysis of lung tissue from GOLD stage 0 cigarette smokers and non-smoking controls revealed ZIP8 mRNA and protein to be significantly increased in the lungs of smokers. We translated these findings into a mouse model of chronic cigarette smoke exposure using a transgenic ZIP8 overexpressing mouse line. ZIP8 overexpression dramatically increased emphysematic pathology, compared to smoke exposed C57/Bl6 control mice. In line with previous studies, our epidemiologic analysis of the 2011-2012 National Health and Nutrition Examination Survey revealed blood Cd levels of smokers correlated with lower Zn serum levels. Based on our findings, we contend ZIP8 (open full item for complete abstract)

Committee: Daren Knoell PharmD (Advisor); Estelle Cormet-Boyaka PhD (Committee Member); Mark Failla PhD (Committee Member); Joanne Turner PhD (Committee Member) Subjects: Biomedical Research

Doctor of Philosophy, The Ohio State University, 2013, Vision Science

PURPOSE: Dry eye is a prevalent condition that results in tear film changes and potential injury to the ocular surface. Numerous risk factors have been identified as playing a crucial role in the development and progression of this disease, and cigarette smoke exposure may serve as an additional risk factor. It has been suggested that highly oxidative components released from tobacco during the burning phase may interact and alter the oily component of the tears, ultimately destabilizing it and increasing evaporation. The purpose of this study is to determine whether cigarette smokers are more likely to present with the symptoms and signs of dry eye compared to nonsmokers. METHODS: Eligible participants between 18-44 years were enrolled into the study after phone screening. Subjects completed a questionnaire assessing ocular irritation symptoms while cigarette smokers with a three-year history of daily cigarette smoking completed a questionnaire inquiring about their smoking habits. Clinical tests used in dry eye testing (ocular surface examination and staining, tear breakup time, and phenol red thread test) were conducted. Overall dry eye status was assessed using the Japanese Dry Eye Criteria. Basal tear samples were collected from each eye using microcapillary tubes and stored at -80°C until analysis of total protein, tumor necrosis factor-alpha (TNF-a), interleukin-6 (IL-6), and hexanoyl-lysine (HEL) concentrations. Imaging studies were conducted to assess tear film lipid thickness, tear film thickness, and thinning rates. Lipid layer images were captured and graded for appearance by the examiner and a masked image reader to evaluate for inter-observer agreement using the Yokoi scale. Outcomes for the right eye only were evaluated using multivariate logistic regression (adjusted for age, gender, and humidity), Fisher Exact Test, and nonparametric statistics. RESULTS: Sixty-five participants were enrolled in the study (45 nonsmokers, 20 smokers). Mean ages we (open full item for complete abstract)

Committee: Heather Chandler (Advisor); Fogt Nicklaus (Committee Member); Parinandi Narasimham (Committee Member); Walline Jeffrey (Committee Member) Subjects: Environmental Science; Epidemiology; Health; Public Health

PhD, University of Cincinnati, 2010, Medicine : Toxicology (Environmental Health)

Chronic obstructive pulmonary disease (COPD) is expected to be the fourth leading cause of worldwide deaths within 20 years. The economic burden of COPD is measured by the billions of dollars in the United States, and increasing worldwide disease prevalence will place additional strains on the global economy. The chief cause of COPD is long term cigarette smoking, and most smokers will develop COPD if smoking-related, extrapulmonary diseases don't claim their lives beforehand. In conjunction with smoking, the development of COPD is modified by genetics, environmental exposures (e.g., air pollution, occupational exposures), and infections. COPD is ultimately a failure of proper breathing, and most patients initially seek doctor consultation for dyspnea. Airflow restriction is brought about by a combination of chronic bronchitis, emphysema, and small airway disease, though the extent of each varies within individual patients. These pulmonary maladies result from inflammation, fibrosis, mucus hypersecretion, and alveolar destruction. The inflammation is the best correlate of disease severity in patients, and is critically involved in disease development experimentally. Attention has traditionally been centered on the roles of macrophages and neutrophils in disease development, but the roles of lymphocytes (T cells, B cells, NK cells) have recently received increased attention. However, the cellular mechanisms involved in COPD pathogenesis are not well-characterized. The stimulus driving the inflammatory response in COPD patients is obfuscated by frequent infections, smoking history, frequent coincidence of tumors, environmental exposures, and aging. The hypothesis tested in this dissertation is that chronic cigarette smoke exposure, as the sole stimulus, activates the pulmonary immune system. Further, I hypothesize that activation of both the innate and adaptive pulmonary immune system drives the development and progression of COPD. Using this hypothesis as a guide, I (open full item for complete abstract)

Committee: Michael Borchers PhD (Committee Chair); Divaker Choubey PhD (Committee Member); George Deepe MD (Committee Member); Ranjan Deka PhD (Committee Member); Dennis McGraw PhD (Committee Member) Subjects: Immunology

PhD, University of Cincinnati, 2006, Medicine : Toxicology (Environmental Health)

Chronic obstructive pulmonary disease (COPD) is major public health problem worldwide induced by cigarette smoking. The pathogeneses of COPD is characterized by progressive difficulty in breathing and excessive mucus production. Previous studies have demonstrated that acrolein, a constituent of cigarette smoke increased mucin 5 (subtype A and C) (MUC5AC) production in the airways, however, the mechanism is unclear. The overall hypothesis of this dissertation is that acrolein increases MUC5AC production through activation of matrix metalloproteinases (MMPs). In airway epithelial cells, acrolein increased MUC5AC transcripts independent of oxidative stress, via a ligand-dependent, epidermal growth factor receptor (EGFR) and mitogen activated protein kinase (MAPK) activation. Acrolein increased MMP9 and MMP14 activity in vitro and in vivo. Small interfering (si) RNA to MMP9, MMP14 and a disintegrin and metalloproteinase domain protein (ADAM) 17 inhibited the acrolein-induced increase in MUC5AC transcripts in vitro. Acrolein-induced increase in MUC5AC transcripts and protein was lower in gene-targeted MMP9 mice (Mmp9(-/-)) than in Mmp9(+/+) mice. Acrolein increased MMP9 and MMP14 transcripts via an EGFR-MAPK dependent mechanism and decreased the transcript level of tissue inhibitor of metalloproteinase protein (TIMP) 3, an endogenous inhibitor of ADAM17, MMP9 and MMP14 in vitro and in vivo. Thus, acrolein activates MMP9 to increase MUC5AC transcripts and protein via an initial EGFR ligand dependent mechanism. Chronic exposure to acrolein increases the protein levels and activity of MMP9 and MMP14, and decreases the transcript level of TIMP3 to initiate a positive feedback loop leading to persistent MUC5AC production.

Committee: Dr. George Leikauf (Advisor) Subjects: Biology, Cell

Doctor of Philosophy, The Ohio State University, 2004, Ohio State University Nutrition

Oxidative and nitrative stress play pivotal roles in the etiology of chronic diseases such as cancer and heart disease. Therefore, investigations to determine the effects of oxidative and nitrative stress on dietary antioxidant utilization are critical for our understanding of chronic disease prevention. To date, the impact of these stressors on vitamin E utilization in humans is controversial. Therefore, for this dissertation, we hypothesized that oxidative and nitrative stress from cigarette smoking will alter vitamin E utilization such that smokers have higher dietary requirements for vitamin E than nonsmokers. Using novel analytical techniques in liquid chromatography/mass spectrometry, we determined that the increased reactive nitrogen species associated with cigarette smoking caused a doubling of plasma nitro-gamma-tocopherol. Furthermore, using deuterium labeled alpha-tocopherols, we observed that smokers, compared with nonsmokers, had a 13% faster plasma alpha-tocopherol disappearance, suggesting that alpha-tocopherol functions in vivo as an antioxidant. Further, smokers' alpha-tocopherol disappearance rates correlated with plasma ascorbic acid concentrations, suggesting that higher plasma ascorbic acid concentrations could prevent the rapid alpha-tocopherol disappearance. Therefore, we conducted a double-blind, placebo-controlled, cross-over investigation in smokers and nonsmokers who were provided supplemental ascorbic acid (2-weeks, twice daily, 500 mg) or placebo prior to evaluating vitamin E disappearance kinetics. Plasma ascorbic acid concentrations doubled in both groups in response to the supplement compared to the placebo. In smokers during placebo treatment, vitamin E disappearance kinetics were again faster than in nonsmokers. However, during vitamin C supplementation, smokers' vitamin E disappearance was normalized. Plasma F2alpha-isoprostanes, a marker of lipid peroxidation, remained 34% higher than nonsmokers and vitamin E metabolite production (open full item for complete abstract)

Committee: Tammy Bray (Advisor) Subjects: Health Sciences, Nutrition