Doctor of Philosophy, The Ohio State University, 2012, Biomedical Engineering

This work was conducted in order to assess the role that the mitochondrial network plays in cardiovascular disease. More specifically, we first conducted studies to determine which bioenergetic factors control changes in the mitochondrial network by exposing cultured endothelial cells to specific chemical treatments. Following this work, we used a parallel plate flow chamber and media recirculation system to expose cultured endothelial cells to simulated ischemia (I)/ reperfusion (RP) injury in order to determine if changes in the mitochondrial network occur upon I/RP and delineate the molecular mechanisms that govern them. The mitochondrial network is dynamic with conformations that vary between a tubular continuum and fragmented state. The equilibrium between mitochondrial fusion/fission, as well as the organelle motility, determine network morphology and ultimately mitochondrial/cell function. Network morphology has been linked with the energy state in different cell types. As stated, in the first part of this study, we examined how bioenergetic factors affect mitochondrial dynamics/motility in cultured vascular endothelial cells (ECs). ECs were transduced with mitochondria-targeted green fluorescent protein (mito-GFP) and exposed to inhibitors of oxidative phosphorylation (OXPHOS) or ATP synthesis. Time-lapse fluorescence videos were acquired and a mathematical program that calculates size and speed of each mitochondrial object at each time frame was developed. Our data showed that inner mitochondrial membrane potential, ATP produced by glycolysis, and, to a lesser degree, ATP produced by mitochondria are critical for maintaining the mitochondrial network, and different metabolic stresses induce distinct morphological patterns (e.g., mitochondrial depolarization is necessary for “donut” formation). Mitochondrial movement, characterized by Brownian diffusion with occasional bursts in displacement magnitude, was inhibited under the same conditions that resulted i (open full item for complete abstract)

Committee: B. Rita Alevriadou PhD (Advisor); Keith Gooch PhD (Committee Member); Richard Hart PhD (Committee Member); Thomas Lemberger PhD (Committee Member) Subjects: Biology; Biomedical Engineering; Biomedical Research; Biophysics; Cellular Biology; Computer Science; Engineering; Mathematics; Mechanical Engineering

Master of Science, The Ohio State University, 2009, Biomedical Engineering

The focus of this project was to elucidate the effects of ischemia/reperfusion on mitochondrial superoxide production by cultured endothelial cells in a parallel plate flow chamber in real time. To accomplish this, we used the mitochondria-targeted superoxide-specific fluorescent probe mitoSOX to determine parameters for its most effective use in a system composed of a parallel-plate flow chamber with cultured endothelial cells, a Nikon epifluorescence microscope, and digital image processing software. Based on the literature, the probe's mitochondrial specificity is linked with the cell mitochondrial membrane potential. This made it necessary to study the effects of ischemia/reperfusion on mitochondrial membrane potential because of the possibility for mitoSOX to leak out of the mitochondria upon loss of mitochondrial membrane potential. The fluorescent probe rhodamine 123 was used in a similar manner as mitoSOX to accomplish this goal. The combination of the novel flow system and mitoSOX enabled us to obtain data comparable to that of a confocal microscope, as verified by the use of a variety of positive controls (both static endpoint images and real time analysis). Experiments using mitoSOX during ischemia/reperfusion showed a higher rate of mitochondrial superoxide production than that of shear alone, while the same experiments using rhodamine 123 showed a loss of mitochondrial membrane potential during ischemia and a partial recovery upon reperfusion. These studies may help us understand the mechanisms of injury on the mitochondria of coronary artery endothelial cells following cardiac ischemia/reperfusion.

Committee: Barbara R. Alevriadou PhD (Advisor); Juan Crestanello MD (Committee Member) Subjects: Cellular Biology; Mechanical Engineering; Molecular Biology

Doctor of Philosophy, The Ohio State University, 2006, Psychology

Activation of the HPA-axis is among the first responses to cerebral ischemia, and glucocorticoid exposure prior to and following stroke is a critical determinant of ischemic outcome. Perinatal environment may be an important determinant of HPA-axis efficiency, influencing the onset of psychopathology and age-related disease. The present work examined the effects of brief (BMS) and extended (EMS) maternal separation, and prenatal stress (PNS), on stroke recovery in adult mice. Despite improved HPA-axis responsivity to acute stressors, BMS male mice had significantly more ischemia-induced neuronal death and increased functional deficits following MCAO in adulthood. The increase in corticosterone-induced neuronal death, and increased inflammation, suggest that BMS mice are more sensitized to the detrimental effects of elevated corticosterone during ischemia. Female BMS mice exhibited similar exacerbation of stroke outcomes to the males when exposed to the MCAO model of focal ischemia, but not the CA/CPR model of global ischemia. EMS and PNS had minimal consequences on focal ischemic outcome in male and female mice. Though additional experiments are needed to determine mechanisms, these studies clearly demonstrate that neonatal environment can drastically affect adult sensitivity to ischemic injury by altering the HPA-axis and inflammatory responses. Psychobiological determinants of stroke outcome are not limited, however, to manipulations of the early environment. Affiliative social interaction via pair-housing was determined to decrease infarct size, functional deficits, and inflammation in comparison to socially isolated mice. In addition, pair-housing reduced the negative consequences of BMS, with pair-housed BMS males exhibiting decreased infarct and functional deficits compared to socially isolated BMS males. In contrast to affiliative social behaviors, post-stroke depression impairs functional recovery and increases mortality following stroke. The final experimen (open full item for complete abstract)

Committee: A. DeVries (Advisor) Subjects: Psychology, Psychobiology

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

Committee: Not Provided (Other) Subjects:

MS, University of Cincinnati, 2023, Arts and Sciences: Chemistry

Neuroinflammation, oxidative stress, and glutamatergic excitotoxicity are prevalent in several neurological disorders including stroke, substance abuse, and neurodegenerative diseases. Chemical compounds and biomolecules which can ameliorate those conditions are gaining interest for new treatments. Despite many advances in understanding brain anatomy and physiology, the underlying neuropathological mechanisms behind ischemic stroke are still poorly understood. The purine nucleosides adenosine and guanosine have been shown to exhibit neuroprotective behavior in both in vivo and ex vivo models of ischemia. However, real-time detection of guanosine sub-second signaling dynamics in the brain is not understood. Various techniques have been developed for the detection of guanosine in vivo and in in vitro. We have used fast-scan cyclic voltammetry (FSCV), a novel electrochemical technique for real-time detection of the neurochemical release in sub-second timescales at carbon-fiber microelectrodes (CFME). Previously our lab has observed a significant increase in the concentration of guanosine during ischemia with the help of FSCV, showing a neuroprotective effect in ischemia. Despite prior studies, it is still unknown how guanosine released during ischemia is impacted as the function of ischemic severity. Here, we have developed an ex vivo oxygen-glucose deprivation model to investigate the guanosine signaling changes as a function of ischemic severity. Characterization of three different ischemic conditions was studied: normoxia, mild ischemia, and severe ischemia with the help of an optically dissolved oxygen sensor. triphenyl tetrazolium chloride assay and immunohistochemical staining were used to validate these ischemic conditions. Overall, we have successfully developed and maintained three different ex vivo experimental ischemic condition.

Committee: Ashley Ross Ph.D. (Committee Chair); Ryan White Ph.D. (Committee Member); Anthony Grillo Ph.D. (Committee Member) Subjects: Analytical Chemistry

Bachelor of Science (BS), Ohio University, 2023, Neuroscience

Brain arteriovenous malformation (bAVM) is a neurovascular disease in which the connections between arteries and veins become enlarged, abnormal, and prone to rupture. While AVMs are rare, seen in less than one percent of adults, they account for two percent of all hemorrhagic strokes in adults and are the most common cause of hemorrhagic strokes in children. Brain AVMs can also cause headaches, neurological deficits, and even seizures. Despite these serious consequences, treatment options for bAVM remain highly invasive and are not possible for many patients. Understanding the role of other brain cell types in the context of this neurovascular disease could provide alternative treatment options to test. In this thesis, a genetically induced mouse model of AVM was used to better understand the consequences of the disease for the brain. In our model, the gene Rbpj, which encodes a transcription factor and is a downstream target of Notch signaling, was deleted from endothelial cells just after birth (postnatal day (P) 1). While in our mouse model the genetic mutation is induced in endothelial cells, which form blood vessels, other brain cell types, such as pericytes and microglia are also affected. However, it is not known whether astrocytes, another important brain cell type, are affected in our bAVM model. Astrocytes are important in tissue homeostasis of the brain and are closely associated with endothelial cells and capillary blood vessels in the brain. In many neurological disorders, astrocytes change their behavior and may show astrocyte reactivity. Astrocyte reactivity is characterized by changes in shape, increased proliferation, altered gene expression and metabolic function. In our Rbpj-induced mouse model of AVM, I investigated consequences of the disease for astrocytes, hypothesizing that in our model, astrocytes would show characteristics of reactivity and formation of glial scars. When Rbpj was deleted at P1, I found that affected astrocyte (open full item for complete abstract)

Committee: Janet Duerr (Advisor); Corinne Nielsen (Advisor) Subjects: Biology; Biomedical Research; Cellular Biology; Molecular Biology; Neurobiology; Neurology; Neurosciences

Doctor of Philosophy (PhD), Ohio University, 2023, Chemistry and Biochemistry (Arts and Sciences)

Stroke and heart attack are among the leading causes of death in the United States and worldwide. The high mortality rate is alarming given the wide availability of therapies for these illnesses. The mechanisms of action of these two diseases are remarkably similar, despite the fact that they are linked to two quite distinct organs in our body; in both, there is significant oxygen deprivation at the cellular level. Nitorooxidative stress occurs in physiological system due to the imbalance between Nitric Oxide (NO) and peroxynitrite (ONOO-). Using electrochemical nanosensors1,2 and a hypoxic chamber (which can control O2 from 21% to 0%), nitrooxidative stress in the endothelial and neural systems was studied, as well as two potential treatments (L-arginine and vitamin D3). Additionally, a connection was made between the protein HIF-1α and nitrooxidative stress. According to experimental data, L-arginine and vitamin D3 treatments can restore the [NO]/[ONOO-] balance in the endothelial system by up to 73 % and 69%, respectively. L-arginine and vitamin D can help the neural system's balance by up to 61% and 8%, respectively. Both L-arginine and vitamin D3 were also found to be effective in downregulation of HIF-1α in severe hypoxic conditions.

Committee: Tadeusz Malinski (Advisor); Michael Held (Committee Member); Katherine Cimatu (Committee Chair); Krisanna Machtmes (Committee Member); Howard Dewald (Committee Member) Subjects: Biochemistry; Chemistry

PhD, University of Cincinnati, 2022, Medicine: Systems Biology and Physiology

Heart failure (HF) is a chronic condition that is the result of pathological cardiac events including cardiac hypertrophy and myocardial infarction, being the most prevalent. Pathological cardiac hypertrophy is a mal-adaptive response contributing to heart failure via loss of cardiomyocytes, decreased contractile properties, and increased interstitial fibrosis. Along with hypertension, myocardial ischemia/reperfusion (I/R) injury is a common mediator of pathological cardiac hypertrophy and remodeling through cardiomyocyte cell death and the activation of the innate immune response. Human Antigen R (HuR) is a widely expressed mRNA binding protein that our lab has previously shown to play a key role in cardiomyocyte hypertrophy in vitro and in vivo. However, the specific mechanism, activation, and post-transcriptional modulation of HuR in pathological cardiac hypertrophy and post-ischemic cardiac remodeling has not been delineated. Firstly, we sought to determine the role of HuR in cardiomyocyte hypertrophy. We demonstrate that HuR undergoes cytoplasmic translocation following treatment with phenylephrine or angiotensin II, agonists of two independent Gaq-coupled GPCRs known to induce hypertrophy. Gq-mediated HuR activation is dependent on p38 MAP kinase, but not canonical Gq-PKC signaling. Furthermore, HuR activation is necessary for Gq-mediated hypertrophic growth of cardiomyocytes as siRNA-mediated knockdown of HuR inhibits in vitro cardiomyocyte hypertrophy. Additionally, overexpressing HuR in cardiomyocytes is sufficient to induce hypertrophic cell growth. Next, to delineate the downstream mechanisms of HuR's translocation promoting cardiomyocyte hypertrophy, our results suggest that HuR mediates the transcriptional activity of NFAT (nuclear factor of activated T cells), a hallmark of pathological cardiac hypertrophy. The results presented here identify HuR as a novel mediator of cardiac hypertrophy downstream of the Gq-p38 MAPK pathway. To furthe (open full item for complete abstract)

Committee: Michael Tranter Ph.D. (Committee Member); Walter Jones Ph.D. (Committee Member); Jo El Schultz Ph.D. (Committee Member); John Lorenz Ph.D. (Committee Member); Sakthivel Sadayappan Ph.D. (Committee Member); Onur Kanisicak PhD (Committee Member) Subjects: Physiology

MS, University of Cincinnati, 2022, Medicine: Clinical and Translational Research

Background: Kidney Transplantation is the treatment of choice for end-stage kidney disease (ESKD) as it confers prolonged life and improved quality of life at a fraction of the cost of dialysis. In a minority of cases, delayed graft function (DGF) occurs, which increases the risk of allograft rejection and decreases allograft survival. Studies have shown that prolonged ischemia time is associated with the development of DGF but there is a paucity of granular data regarding ischemia times and outcomes in pediatric patients. Recently, organ procurement organizations have been utilizing machine perfusion during donor organ transportation with less DGF in adults, but no such studies exist in pediatric patients. Therefore, we sought to investigate kidney transplantation in a pediatric population to identify predictors and protective factors of DGF. Methods: This is a retrospective cohort study of patients aged 18 months to 21 years who underwent kidney transplantation at Cincinnati Children's Hospital Medical Center between 11/1/2017 and 11/30/2021. DGF was defined as receiving kidney replacement therapy (hemodialysis or continuous kidney replacement therapy) within 7 days post-transplant. Categorical data were analyzed using Fisher's exact test and continuous data were analyzed using Wilcoxon rank-sum test. Results: Nine of 89 (10%) kidney transplant patients developed DGF. There was no significant difference in sex, race, age at transplant, etiology of kidney disease, pre-transplant dialysis, pre-transplant calculated panel reactive antibody level, organ donor type, human leukocyte antigen mismatch, kidney donor profile index or lymphocyte-depleting induction immunosuppression. In the entire cohort, patients with DGF had significantly longer warm ischemia times (49 vs. 37 minutes, p=0.002) and were more likely to have received a deceased donor allograft (p=0.04). Patients with DGF who received deceased donor kidneys were less likely to receive machine pe (open full item for complete abstract)

Committee: Scott Langevin Ph.D. (Committee Member); Liang Niu Ph.D. (Committee Member); David Hooper (Committee Member) Subjects: Surgery

PhD, University of Cincinnati, 2021, Arts and Sciences: Chemistry

Guanosine is a crucial molecule within the central nervous system known to play a role in neuromodulation and protection in the instance of chemical or physical damage to the brain. Neurochemical release is a dynamic process, necessitating an analytical method that can capture rapid and subsecond signaling events. Fast-scan cyclic voltammetry (FSCV) at carbon-fiber microelectrodes is an electrochemical technique enabling detection of rapidly released electroactive compounds. In this dissertation, I have detailed an FSCV technique for the quantitation and characterization of dynamic guanosine events within living brain tissue. In the first chapter, I describe the chemistry and neurobiology of guanosine, covering its role within the central nervous system, the metabolic pathways of guanosine and its regulation, and its receptors and transporters. I also describe extant and popular detection techniques for guanosine and its sister compound adenosine. In Chapter 2, I describe the guanosine FSCV waveform I developed for my first graduate project. Here, I go into detail regarding the full characterization of this waveform and present a proof-of-concept for in-tissue detection of guanosine. In the following chapter, I present an additional FSCV waveform allowing for the codetection of both guanosine and adenosine. This waveform is a modified version of the adenosine waveform which enables simultaneous detection of the purine ribonucleosides. This waveform could prove useful in the future for codetection of the ribonucleosides, as earlier studies have suggested an intricate interaction between guanosine and adenosine with important downstream modulatory effects. In the fourth chapter, I use the guanosine waveform to detect endogenous, spontaneous guanosine transients ex vivo. Guanosine events were recorded during a control period and in response to a drug and neurochemical injury. This study marks the first ever recordings of subsecond, dynamic guanosine events in the brain (open full item for complete abstract)

Committee: Ashley Ross Ph.D. (Committee Chair); Ryan White (Committee Member); Mark Baccei Ph.D. (Committee Member); Noe Alvarez Ph.D. (Committee Member) Subjects: Chemistry

PhD, University of Cincinnati, 2020, Medicine: Molecular, Cellular and Biochemical Pharmacology

Mitochondrial Calcium loading augments oxidative metabolism to match functional demands during times of increased work or injury. Physiological range of mitochondrial Calcium dynamics regulate energy production by activating key enzymes in metabolic pathways. Disruption of mitochondrial Calcium flux alters energy production leading to metabolic dysfunctions. Moreover, mitochondrial Calcium overload also directly causes mitochondrial rupture and cell death by inducing mitochondrial permeability transition. Thus, control of mitochondrial Calcium dynamics is essential for maintaining mitochondrial function and cell function. The mitochondrial Calcium uniporter (MCU) is the complex that mediates mitochondrial Calcium influx, and its activity is modulated by partner proteins in its molecular complex. While the pore-forming subunit MCU is responsible for acute mitochondrial Calcium uptake, MCUb is suggested as an inhibitory subunit of the pore preventing acute Calcium uptake into mitochondria. In skeletal muscle, its unique feature of varying metabolic rate depending on muscle demand marks the importance of mitochondrial Calcium dynamics in regulating energy production. Here, we examined the role of MCU and MCUb in skeletal muscle function and metabolic function by generating mouse models for skeletal muscle-specific deletion of MCU and MCUb, separately. Skeletal muscle-specific deletion of MCU in mice inhibited acute mitochondrial Calcium influx and Calcium-stimulated mitochondrial respiration, resulting in a preferential shift towards fatty acid metabolism with reduced body fat with aging. On the other hand, MCUb deletion in skeletal muscle resulted in an increase in glycolysis, as well as a decrease in fatty acid oxidation with increased body fat mass with aging. Together, these results demonstrate that mitochondrial Calcium regulation underlies skeletal muscle fuel selection and impacts total homeostatic metabolism. In the heart, mitochondrial Calcium overloa (open full item for complete abstract)

Committee: Jeffery Molkentin Ph.D. (Committee Chair); Taosheng Huang M.D. Ph.D. (Committee Member); Evangelia Kranias Ph.D. (Committee Member); Sakthivel Sadayappan Ph.D. (Committee Member); Jo El Schultz Ph.D. (Committee Member) Subjects: Molecular Biology

Master of Science, The Ohio State University, 2018, Biomedical Engineering

The mechanisms underlying CaMKII-induced arrhythmias in ischemia/reperfusion (I/R) are not fully understood. My thesis research tested the hypothesis that CaMKII increases late Na+ current (INa,L) via phosphorylation of Nav1.5 at Ser571 during I/R, thereby increasing arrhythmia susceptibility. Action potential duration (APD) and arrhythmic events were measured by optical mapping in isolated, Langendorff-perfused mouse hearts during global ischemia and reperfusion. To provide mechanistic information on the role of CaMKII-dependent phosphorylation of Nav1.5 in arrhythmia, Scn5a knockin mice expressing Nav1.5 with constitutive phosphorylation [Nav1.5-Ser571Glut (S571E)] or ablation [Nav1.5-Ser571Ala (S571A)] of the CaMKII site at Ser571 were used. Wildtype (WT) hearts showed a significant increase in the levels of phosphorylated CaMKII and Nav1.5 at Ser 571 [(p-Nav1.5(S571)] following 15 minutes of ischemia (just before onset of reperfusion). Optical mapping studies revealed a significant prolongation of APD, increased recovery time, and increased arrhythmia susceptibility during I/R in S571E and WT mice compared to S571A mice. Pretreatment of hearts with Na+ channel blocker mexiletine (10 uM) increased recovery of APD and reduced arrhythmia susceptibility in WT mice during I/R. We conclude that CaMKII-dependent phosphorylation of Nav1.5 is a crucial driver for increased INa,L, arrhythmia susceptibility during I/R. Selective targeting of this CaMKII-dependent pathway may have therapeutic potential for reducing arrhythmias in the setting of I/R.

Committee: Tom Hund Dr. (Advisor); Sakima Smith Dr. (Committee Member) Subjects: Biomedical Engineering

Doctor of Philosophy (PhD), University of Toledo, 2017, Experimental Therapeutics

Ischemic stroke is caused by a blockage of the blood flow to the brain resulting in neuronal and glial hypoxia leading to inflammatory and free radical-mediated cell death. Reactive oxygen species (ROS) formed in excess under hypoxic conditions cause protein, DNA and lipid oxidation. Nitric oxide (NO) formed by NO synthase (NOS) is known to be protective in ischemic stroke, however NOS has been shown to `uncouple' under oxidative conditions to instead produce superoxide. Nitrones are antioxidant molecules that are shown to trap ROS to then decompose and release NO. In this study, the PBN-type nitrone 5 was designed such that its decomposition product is a NOS inhibitor, effectively leading to NOS inhibition specifically at the site of ROS production. The ability of 5 to spin-trap radicals and decompose into the putative NOS inhibitor was observed using EPR and LC-MS/MS. The pro-drug concept was tested in vitro by measuring cell viability and inhibitor formation in SH-SY5Y cells subjected to oxygen glucose deprivation (OGD). 5 was found to be more efficacious and more potent than PBN, and was able to increase pAkt while reducing nitrotyrosine and cleaved caspase-3 levels. Doppler flowmetry on anesthetized mice showed an increased cerebral blood flow upon intravenous administration of 1 mg/kg 5, but a return to baseline upon administration of 10 mg/kg, likely due to its dual nature of antioxidant/NO-donor and NOS-inhibition properties. Mice treated with 5 after permanent middle cerebral artery occlusion (pMCAO) performed better in neurobehavioral assessments and exhibited a > 30% reduction in infarct volume. This efficacy is proposed to be due to higher formation of the NOS inhibitor decomposition product in ischemic tissue observed by LC-MS/MS, resulting in region specific effects limited to the infarct area.

Committee: Zahoor Shah Ph.D. (Committee Chair); Isaac Schiefer Ph.D. (Committee Member); F. Scott Hall Ph.D. (Committee Member); Wissam AbouAlaiwi Ph.D. (Committee Member) Subjects: Biochemistry; Neurobiology; Neurosciences; Organic Chemistry; Pharmacology; Physical Chemistry

Master of Science, Northeast Ohio Medical University, 2017, Integrated Pharmaceutical Medicine

Myocardial ischemia reperfusion (IR) injury has been shown to cause mitochondrial dysfunction. The electron transport chain (ETC) is a major source of superoxide and other superoxide derived reactive oxygen species during ischemia and reperfusion. Previous studies suggest that the downregulation of ETC, Krebs cycle, and antioxidant enzymes in the mitochondria occur as a result of increased oxidative stress. SOD2 is one of the primary antioxidants in the mitochondrial matrix. It is capable of scavenging superoxide into hydrogen peroxide. To test the therapeutic potential of increased superoxide scavenging in murine models, we subjected cardiac specific human SOD2 overexpressing (SOD2TG) murine hearts to 30 minutes of ischemia and 45 minutes of reperfusion using the Langendorff isolated heart system. SOD2TG hearts were relatively protected from impairment of electron transport activity in complex I-IV as well as downregulation of Krebs cycle enzyme activities. However, SOD2 overexpressing hearts had selectively decreased basal respiratory enzyme kinetics without indication of impairment of respiratory coupling and hydrogen peroxide scavenging.

Committee: Yeong-Renn Chen Dr. (Advisor); Denise Inman Dr. (Committee Member); William Chilian Dr. (Committee Member) Subjects: Biology

MS, University of Cincinnati, 2017, Pharmacy: Pharmaceutical Sciences

(1S, 2E, 4R, 6R,-7E, 11E)-2, 7, 11-cembratriene-4, 6-diol (4R) is one of the cembranoids found in tobacco leaves. Previous studies have found that 4R protected acute rat hippocampal slices against neurotoxicity induced by N-methyl-D-aspartate (NMDA) and against the toxic organophosphorus compounds paraoxon and diisopropylfluorophosphate (DFP). Furthermore, 4R reduced the infarct size in a rodent ischemic stroke model and neurodegeneration caused by DFP and 6-hydroxydopamine (6-OHDA). The present study expanded our previous study focusing on the effect of 4R in N9 cells (murine-derived microglia cell line) polarization. The results showed that 4R promoted M2 activation of N9 cells and inhibited M1 activation of N9 cells induced by lipopolysaccharide (LPS) or oxygen glucose deprivation (OGD). LPS or OGD-induced M1 activation marker-inducible nitric oxide synthase (iNOS) of N9 cells was attenuated by 1uM of 4R treatment, which was 69.4% and 56.4% of vehicle control, respectively. In addition, 1uM 4R promoted M2 activation marker-Argnase-1 of N9 cells under LPS or OGD conditions, which was 192.7% and 188.0% of vehicle control, respectively. Furthermore, the conditioned medium of 4R-treated post-OGD N9 cells protected neuro2a cells from OGD-induced injury. The cells viability increased by 54.5% by treatment with the conditioned medium of 4R-treated post-OGD N9 cells compared with the conditioned medium from post-OGD N9 cells without 4R. Furthermore, cytokines release measured by ELISA showed that 4R increased anti-inflammatory cytokine IL-10 production and inhibited pro-inflammatory cytokine TNF-a release from N9 cells induced by OGD. In conclusion, the present study indicates that 4R exhibits anti-inflammatory properties by modulating polarization of microglia toward M2 subtype.

Committee: Jiukuan Hao Ph.D. (Committee Chair); Joan Garrett Ph.D. (Committee Member); Jianxiong Jiang Ph.D. (Committee Member) Subjects: Pharmaceuticals

Doctor of Philosophy, Case Western Reserve University, 2017, Molecular Medicine

Intestinal ischemia/reperfusion (I/R) injury is a relatively common pathological condition that can lead to multi-organ failure and mortality. Regulatory mechanism for this disease is poorly understood, although it is established that circulating pathogenic natural IgM, which is primarily produced by B1a cells outside of the peritoneal cavity, are integrally involved. CD6 was originally identified as a marker for T cells and later found to be present on some subsets of B cells in humans, however, whether CD6 plays any role in intestinal I/R induced injury and if so, what are the underlying mechanisms, remain unknown. Here we report that CD6-/- mice were significantly protected from intestinal inflammation and mucosal damage compared to WT mice in a model of intestinal I/R-induced injury. Mechanistically, we found that CD6 was selectively expressed on B1 cells outside of the bone marrow and peritoneal cavity, and that pathogenic natural IgM titers were reduced in the CD6-/- mice in association with significantly decreased B1a cell population. Our results reveal an unexpected role of CD6 in the pathogenesis of intestinal IR-induced injury by regulating the self-renewal of B1a cells.

Committee: Christopher King MD/PhD (Committee Chair); Feng Lin PhD (Advisor); Neetu Gupta PhD (Advisor); Trine Jorgensen PhD (Committee Member); Brian Hill MD/PhD (Committee Member); Thomas Hamilton PhD (Committee Member) Subjects: Immunology

Doctor of Philosophy, The Ohio State University, 2017, Neuroscience Graduate Studies Program

Social isolation is a major risk factor for disease onset and progression, and has been correlated with all-cause mortality. Despite converging evidence from animal and human studies recapitulating the physiological benefits of social interaction, the mechanisms by which social environment influences health remain underspecified. In affiliative species, social isolation is a psychological stressor, capable of activating the hypothalamic pituitary adrenal (HPA) axis and altering gene expression of immune cells. These physiological changes have the potential to sensitize immune responses. The innate immune cells of the central nervous system, microglia, can become primed and will exert a prolonged and maladaptive response to additional immune stimulation. Thus, we hypothesized that social isolation can sensitize microglia, and that an exaggerated inflammatory response underlies the detrimental consequences of isolation on cerebral ischemia outcome. Increased expression of major histocompatibility II (MHC II) and a retraction of microglial processes are the most common indicators of microglial priming. Following a week of social isolation, male mice displayed increased hippocampal and cortical gene expression of MHC II, but the females did not. An elevation in the gene expression of MHC II among male mice is the first indication of isolation-induced microglial priming. When investigating social modulation of microglial reactivity to global cerebral ischemia induced by cardiac arrest/ cardiopulmonary resuscitation, social attenuation of the inflammatory response was evident at 24-hours post-ischemia in both female and male mice. Among males the ischemia-induced increase in expression of pro-inflammatory cytokines was attenuated by social interaction, whereas in the female mice pair housing ameliorated the ischemia-induced elevation of MHC II. These data suggest that social modulation over the neuroinflammatory response to global cerebral ischemia occurs regardless of (open full item for complete abstract)

Committee: A. Courtney DeVries (Advisor) Subjects: Behavioral Sciences; Immunology; Neurobiology; Neurosciences

Doctor of Philosophy, The Ohio State University, 1984, Graduate School

Committee: Not Provided (Other) Subjects: Biology

Doctor of Philosophy, The Ohio State University, 1981, Graduate School

Committee: Not Provided (Other) Subjects: Health Sciences

PhD, University of Cincinnati, 2016, Medicine: Molecular, Cellular and Biochemical Pharmacology

Cardiovascular diseases are the underlying cause for majority (>30%) of deaths worldwide. They include coronary heart disease and peripheral artery disease, conditions characterized by limited blood flow and inadequate oxygenation. Treatment strategies include management of symptoms and risk factors, reduction of oxygen demand and surgical revascularization to increase circulation. Therapeutic revascularization is a potential alternative for patients who are poor candidates for these interventions due to advance disease or co-morbidities. Revascularization involves the genetic or pharmacologic stimulation of vascular growth processes to facilitate tissue perfusion and promote functional recovery. Adaptive vascular growth occurs via capillary vessel growth (angiogenesis) and growth or remodeling of collateral arteries (arteriogenesis). Delivery of angiogenic factors such as fibroblast growth factor 2 (FGF2) to ischemia tissues can stimulate blood vessel growth. FGF2 consists of two classes of protein isoforms generated from alternative translation of the Fgf2 gene, high molecular weight (HMW) FGF2, and low molecular weight (LMW) FGF2. Proof-of-concept studies in animal models of chronic ischemia provided evidence for the therapeutic potential of exogenous LMW FGF2. This promise, however, did not translate into successful clinical use. Currently, the functions of the endogenous FGF2 isoforms in ischemia-induced revascularization are not well understood. Elucidating the function(s) of the FGF2 isoforms in vascular growth is of great clinical importance and may lead to the development of novel pharmacological therapies for ischemic diseases. Mice with a targeted deletion of all FGF2 isoforms (Fgf2-/-), HMW FGF2 (FGF2 LMW-only) and LMW FGF2 (FGF2 HMW-only) were employed to identify the distinct role(s) of the FGF2 isoforms in chronic ischemia. Revascularization was evaluated in mice subjected to chronic hindlimb ischemia using measures of limb function, tissue via (open full item for complete abstract)

Committee: Jo El Schultz Ph.D. (Committee Chair); James B. Hoying Ph.D. (Committee Member); Walter Jones Ph.D. (Committee Member); Ronald Millard Ph.D. (Committee Member); Daria Narmoneva Ph.D. (Committee Member) Subjects: Pharmacology