Doctor of Philosophy, The Ohio State University, 2009, Integrated Biomedical Sciences

A new paradigm in human genetics is the presence of frequent inter-individual variations in copy-number (CNV) of specific genomic DNA segments. One such CNV locus encodes an immune effector protein, complement component C4. Located in the major histocompatibility complex (MHC), human C4 is a constituent of the RP-C4-CYP21-TNX module that exhibits a copy-number variation ranging from 2-10 per diploid genome. C4 CNV leads to parallel quantitative and qualitative variations of C4 proteins. The polymorphic C4 protein can be classified into two isotypes: the acidic C4A and the basic C4B. This dissertation focuses on investigating the quantitative and qualitative diversities of C4 in human systemic lupus erythematosus (SLE).The molecular defects of two North African patients with complete C4 deficiency who developed SLE were determined. These cases underscore the importance of C4 protein in the protection against SLE. To investigate if C4 CNV contributes to differential SLE risk, we developed specific and sensitive quantitative real-time PCR assays to interrogate the copy-numbers of C4A and C4B. Large cohorts of SLE patients and race-matched controls of European, African and Asian ancestries were studied. The mean total C4 copy-numbers in SLE were consistently lower compared to those in controls. Such decrease was mainly due to homozygous and heterozygous deficiencies of C4A. We further genotyped C4 CNV and its closely linked DRB1 gene in the MHC in over 1,000 Caucasian subjects. We obtained evidence for that lower C4A copy-number and HLA-DR3 are overlapping but can be independent risk factors for SLE in Caucasians. The phenotypic serial changes of serum complement proteins C3 and C4, and RBC-bound C4d were characterized in a pilot cohort of SLE patients with defined C4 genotypes. Three distinct C4 protein profiles corresponding to different degrees of disease presentations were observed. In conclusion, low copy-numbers of C4A is a risk factor for SLE among differ (open full item for complete abstract)

Committee: Professor Chack-Yung Yu D.Phil. (Advisor); Professor Kim McBride MD (Committee Member); Professor Haikady Nagaraja PhD (Committee Member); Professor Brad Rovin MD (Committee Member) Subjects: Biomedical Research

Doctor of Philosophy, The Ohio State University, 2003, Medical Microbiology and Immunology

Human populations are endowed with a sophisticated genetic diversity of complement C4 and its flanking genes RP, CYP21 and TNX in the RCCX modules of the major histocompatibility complex (MHC) class III region. Since the sequence polymorphisms and modular variations of the RCCX, and the polygenic and gene size variations of C4A and C4B are a potential root cause in the susceptibility to autoimmune and MHC-associated diseases, these areas are a topic of debate. Novel or improved techniques to accurately study the complex genetic patterns of the RCCX have been developed. Chromosomes with one- , two- , three- and four C4 genes were characterized in four informative families. Mutations that created polymorphic BglII and TaqI sites in RP and C4, respectively, were characterized. PshAI RFLP was developed to detect TNXB-XA recombinants, which causes congenital adrenal hyperplasia (CAH). TaqI and the novel BsaI RFLP's revealed monomodular-L with CYP21A and bimodular structures with CYP21A-CYP21A at frequencies of 20.5% and 22.7% in 22 CAH patients, respectively. The transcript levels of C4A and C4B showed a direct correlation to the respective gene dosages in liver and kidney tissues. Primary cultures of human mesangial cells with equal numbers of C4A and C4B genes demonstrated a constitutively low expression of C4A, but not C4B. The relative level of C4B mRNA increased ~ 2- to 30-fold upon interferon-gamma induction. An analysis of 110 Caucasian SLE patients revealed increases of homozygous C4A deficiency (9.1% vs 0.7%, p=0.0008). Although homozygous C4A deficiency was inherently low in the southern Chinese population, partial C4A deficiency was increased in 291 SLE patients (15.5% vs 7.7%, p=0.007). Furthermore, the distribution of C4A gene dosages was lower in the Caucasian (p=0.0005) and Chinese (p=0.008) patient groups when compared to their respective normal controls. Therefore complete or partial deficiency of C4A is a common risk factor for SLE in two different ethn (open full item for complete abstract)

Committee: Chack Yung Yu (Advisor) Subjects:

MS, Kent State University, 2007, College of Biomedical Sciences

Prostate cancer is the second leading cause of death in men in the USA for the year 2007 and cells are generally resistant to treatments. Hence it is vital to sensitize them prior to treatment. Synchronizing cells in a particular phase of the cell cycle is a simple and efficient method of sensitization. We used aphidicolin to synchronize cells in S-phase of the cell cycle, thus sensitizing them to therapeutic agents. About ninety percent of prostate cancer cells could be synchronized using this DNA polymerase inhibitor. Synchronized cells, when treated with agents such as Apo2L/TRAIL, CPT-11 and Bortezomib, showed increased levels of apoptosis. Combination treatments enabled greatly to reduce doses of the agents used, with prior synchronization in S-phase. Thus, S-phase synchronization might represent a promising avenue of treatment of tumor cells, which are highly resistant to various chemo-irradiation therapies.

Committee: Gail Fraizer (Advisor) Subjects: Biology, Molecular

Master of Science (MS), Bowling Green State University, 2021, Geology

As a main component of the terrestrial hydrological cycle, evapotranspiration (ET) significantly affects soil moisture, atmospheric water vapor content, plant nutrient absorption, and primary production. Thus, accurate estimation of ET is important to provide a better insight into complex processes of the water balance and plant-water interaction. Temporal and spatial estimation of ET over a large area is possible through remote sensing-based land surface energy balance models. In this study, modified Boreal Ecosystem Productivity Simulator (BEPS), a stomatal conductance-based ET model used to estimate the ET rate in the Lower Maumee River watershed for the 2018 growing season. The study area is crop-dominated with corn (a.k.a. maize), soybean, alfalfa, and winter wheat as the main crop types. Given that corn is a C4 plant, which possesses a water-efficient photosynthesis system, and the rest of the crops in the watershed are C3 plants with a less efficient water-related apparatus, this study explores the possible effect of land cover (LC) changes on ET, when LC is modified from the existing state to a simulated 100% corn-covered area. The goal is to understand how the growth of corn monoculture may impact the water balance of the watershed. The study also explores the impact of a range of stomatal conductance values of crops on the ET rate, and stomatal conductance is a measure of stomata openings and water transpiration. The findings show that increasing the corn coverage to 100% does not significantly impact the ET rate in the watershed (overall increase of ET is 5.05% for July and 3.96% for August). The results also suggest that the modeling scenario with the highest values of stomatal conductance may result in significantly increased ET (up to 24.04% for corn and 5.1% for soybean), and as such it agrees with the thermal-based ECOSTRESS ET product derived and validated over the study area over the same growing season (+/- 0.9 mm/day). This study extends the rese (open full item for complete abstract)

Committee: Anita Simic Milas Ph.D. (Advisor); Ganming Liu Ph.D. (Committee Member); Margaret Yacobucci Ph.D. (Committee Member) Subjects: Ecology; Geology; Hydrology; Remote Sensing

Doctor of Philosophy, The Ohio State University, 2016, Molecular, Cellular and Developmental Biology

Complement C4 is an immune protein with a wide range of effector functions, including disposal of apoptotic materials, clearance of immune complexes, and activation of the classical complement pathway resulting in cytolysis of microbes. Homozygous deficiencies of C4 or early complement components (C1q, C1r, or C1s), albeit rare, are strongly associated with the autoimmune disease systemic lupus erythematosus (SLE). Much more common than a complete genetic deficiency is “low” gene copy number (GCN) of C4, which varies among human genomes from two to eight copies. Low GCN of C4, specifically of the isotype C4A, is associated with SLE disease risk. However, it is known that C4A-deficient haplotypes in European Americans are in strong linkage disequilibrium (LD) with HLA allele DRB1*0301 on chromosome 6, which has been associated with other autoimmune diseases, including juvenile dermatomyositis (JDM). It remains a puzzle whether C4A deficiency, DRB1*0301, or both are responsible for the primary disease association because of the strong LD exhibited between the two genetic variants. We assessed GCNs for C4A, C4B, and HLA-DRB1 alleles in genetic risk of JDM. C4A deficiency was a risk factor for JDM independent of DRB1*0301, but the effect size was stronger when C4A deficiency and DRB1*0301 were present together. JDM patients with C4A deficiency had higher prevalence of elevated serum muscle enzymes at disease diagnosis and elevated erythrocyte-bound C4-derived activation products (E-C4d). We also observed that C4A deficiency is a strong risk factor for pediatric SLE susceptibility as is the case for adult SLE reported previously, but the effect size was greater in pediatric populations. Our regression analyses of Caucasian SLE patients and controls suggested that DRB1*0301 was likely secondary to C4A deficiency on disease susceptibility. Given the common observation of C4A deficiency in patients afflicted with JDM or SLE, a logical step forward would be the esta (open full item for complete abstract)

Committee: Chack-Yung Yu D.Phil. (Advisor); Carlos Alvarez Ph.D. (Committee Member); Heithem El-Hodiri Ph.D. (Committee Member); Wael Jarjour M.D. (Committee Member); Yusen Liu Ph.D. (Committee Member) Subjects: Genetics; Immunology; Molecular Biology

Doctor of Philosophy, The Ohio State University, 2004, Medical Microbiology and Immunology

The two isotypes of immune effector proteins complement component C4, C4A and C4B, exhibit different biological functions. The number of C4 genes present in a diploid genome varies from 2 to 6 among different individuals. The variation of C4 gene dosage is always concurrent with three other flanking genes, including RP, CYP21 and TNX. The size of C4 genes can be long (21 kb) or short (14.6 kb), which differs in 6.4 kb due to the presence or absence of an endogenous retroviral sequence in intron 9. Complete or partial deficiency of C4A has been observed to be a risk factor for systemic lupus erythematosus (SLE). However, a deeply ingrained but inaccurate “two-locus” model of human C4 genes had impeded advances on epidemiological studies of C4 and diseases. The first objective of this dissertation was to determine the genetic complexity and protein polymorphism of C4. It was observed that there were good correlations between the number of long C4 genes with C4A protein levels, and the number of short C4 genes with C4B protein levels. The short C4B gene in the second locus not only increased the C4B protein level, but also slightly increased the C4A protein levels coded by the long C4A gene of the first locus. The second objective was to determine the molecular basis of C4 mutations from complete C4 deficiency subjects. Novel C4 mutations were discovered in seven complete deficient subjects. Sequence-specific polymerase chain reaction strategies were created for rapid screenings of known C4 mutations in human populations. The third objective was to study variations of C4 gene dosages and protein polymorphisms in Caucasian and Black SLE patients. When compared with case controls, both Caucasian and Black SLE patients had increased frequencies in deficiencies of total C4 and C4A genes. Protein levels of total C4, C4A and C4B decreased in SLE patients within the same gene dosage groups. The low protein levels of total C4 and C4A in SLE may result from low gene dosages in (open full item for complete abstract)

Committee: Chack-Yung Yu (Advisor) Subjects: Health Sciences, Immunology