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, The Ohio State University, 2016, Oral Biology

Neuroinflammation is a critical feature associated with many neurological diseases. Two potent pro-inflammatory mediators, interleukin-1 (IL-1) and cyclooxygenase-2 (COX-2), are induced and have diverse activities in inflammatory processes and disease progression. One of the mechanisms underlying the multifunctional roles of IL-1 and COX-2 is that they may exert distinct effects in different CNS cell types. We investigated the direct actions of IL-1 on brain endothelial cells, astrocytes, and microglia in cell cultures. We studied the cellular actions of inducible COX-2 in neurons and non-neuronal cells by using two Cox-2 conditional knockout mouse strains. In the first study, we demonstrated that IL-1 exerts distinct cell type-specific action in CNS cells and activates cellular specific signaling pathways. In the second study, we demonstrated that COX-2 induced in neurons may have neurotoxic effects whereas COX-2 induced in non-neuronal cells may have neuroprotective activities. We further uncovered the possible prostaglandin products that may mediate the opposing effects of COX-2 in each of the two cell types. These results together suggest that IL-1 or COX-2 mediated neuroinflammation is the result of the summation of multiple responses from different cell types in the CNS to IL-1 or COX-2.

Committee: Ning Quan (Advisor); John Sheridan (Committee Member); Virginia Sanders (Committee Member); Michael Bailey (Committee Member) Subjects: Immunology; Neurobiology; Neurosciences

Doctor of Philosophy (PhD), Ohio University, 2016, Biological Sciences (Arts and Sciences)

As one of the leading causes of death and long-term disability, stroke brings detrimental burden to its patients and the society. The most common subtype of stroke is ischemic stroke. Current treatment for ischemic stroke is limited. The only FDA approved drug is tissue plasminogen activator (tPA). The application of tPA is restricted within 4.5 hours of stroke onset, due to its severe side effects and broad contraindications. The lethal side effect of tPA is hemorrhage. The usage of tPA and its therapeutic effect has to be compromised to avoid hemorrhage. Studies have been proposing that Zn2+ accumulation has deleterious effect in ischemic neuronal damage, and reducing intracellular Zn2+ overload by Zn2+ chelation improve neuronal survival from cerebral ischemia. In this study, the therapeutic effect of Zn2+ chelation is investigated not only in mice, but also in a newly developed zebrafish model. Severe hypoxia was performed to induce a hypoxic-ischemic brain injury on zebrafish, to mimic the global cerebral stroke in a cardiac arrest. A self-designed chamber was used to perform stable and effective hypoxia. The brain injury was quantified by histological staining of the brain, and the overall survival and behavioral changes of zebrafish after hypoxia. Photothrombotic method was adopted and modified to develop adult zebrafish as a model for focal thrombotic stroke. Rose Bengal was intraperitoneally injected to the zebrafish and a light probe was placed on the optic tectum of the brain. Brain damage was quantified by 2,3,5-Triphenyltetrazolium chloride (TTC) staining and overall recovery. Treatment of tPA was used to confirm thrombosis-induced brain injuries and the feasibility of using zebrafish model to screen thrombolytic candidates. In vitro experiment, spectrophotometry was used to quantify blood clot-lysis (thrombolysis). Thrombosis model in vivo was achieved by photothrombotic method on the mouse femoral artery. The artery reperfusion induced by tPA was (open full item for complete abstract)

Committee: Yang Li (Advisor); Gary Cordingley (Committee Member); Robert Colvin (Committee Member); Daewoo Lee (Committee Member) Subjects: Biomedical Research; Neurosciences

Doctor of Philosophy, The Ohio State University, 2007, Neuroscience

Spinal cord injury (SCI) is a long lasting, debilitating condition with no cure. Cervical SCI is the most common form of human SCI, often leaving patients paralyzed with a 15-20 year decrease in life expectancy. The majority of animal SCI contusion models are focused on thoracic injury. SCI at this level results in deficits almost entirely due to white matter damage that disconnects the rostral nervous system from the caudal spinal cord. Damage at the cervical level is different; in addition to the disconnection, gray matter damage affects the neurons controlling the upper extremities and diaphragm. To investigate injury at the cervical level, we characterized a unilateral C5 cervical contusion model in rats. By examining six-week behavioral recovery after SCI, we demonstrated that functional deficits are dependent upon the severity of injury. Analysis of the histopathology revealed that behavioral consequences are a result of damage to both the gray and white matter. Unilateral injury provides within-subject controls and preserves bladder and respiratory function. Many treatments for experimental rat SCI improve behavioral and histological outcomes but have yet to be implemented after human SCI. Treatments must be safe and tested in clinically relevant models to move from animals to humans. We examined the effects of three different clinically acceptable drugs. Methlyprednisolone and minocycline have anti-inflammatory effects if given after injury. Topiramate blocks glutamate receptors and hence excitotoxicity, an important component of secondary injury. Minocycline and methylprednisolone treatment yielded no significant behavioral or histological improvements when tested after moderate-severe unilateral cervical contusion injury. Topiramate was first tested in a model of excitotoxicity and then after cervical SCI and was compared to NBQX, a standard AMPA-receptor antagonists used in animal models of disease. Both drugs preserved neurons after excitotoxic injury, b (open full item for complete abstract)

Committee: Jacqueline Bresnahan (Advisor) Subjects: Biology, Neuroscience