Cellular and Molecular Physiology Commons^™

Advanced Interactions Of Directed Energy With Retinal Pigment Epithelial Cells And Their Photochemical And Photothermal Responses, Jin B. Ha

Theses & Dissertations

Excess optical radiation can injure the retina through either rapid heat deposition (photothermal damage) or cumulative photo‑oxidative stress (photochemical damage), yet current laser‑safety limits treat these mechanisms as independent. To test that assumption, this dissertation integrated systematic wavelength, duration and temperature‑controlled laser exposures with live/dead fluorescence imaging in a melanin‑loaded hTERT‑RPE1 monolayer model. First, concurrent 447 nm (blue) and 2 µm (infra‑red) beams delivered for 200 s demonstrated a strong thermal–photochemical synergy: each beam alone was sub‑threshold (≤25 % lethality) but together produced 100 % RPE death without exceeding 50 °C, proving that modest heating markedly lowers the photon dose …

Understanding The Role Of Mastl In Colon Homeostasis And Colitis-Associated Cancer Development, Kristina Pravoverov

Theses & Dissertations

Colitis-associated cancer (CAC) is the most devastating complication of longstanding inflammatory bowel disease (IBD). Understanding the mechanisms underlying the switch from damage-repair to dysplasia in IBD is critical for identifying novel therapies to facilitate mucosal healing while mitigating CAC risk. Microtubule-associated serine-threonine kinase-like (MASTL), though crucial in cell growth and repair, is upregulated in sporadic colorectal cancer and CAC. This study sought to delineate the role of MASTL in colitis and CAC development.

First, we examined whether MASTL is associated with colitis and recovery. Review of publicly available data found significant elevation of MASTL and interleukin (IL)-22 in biopsies from …

Elucidating The Luteal Microenvironment: The Role Of Fibroblasts In Luteal Regression, Corrine F. Monaco

Theses & Dissertations

The corpus luteum is a transient endocrine gland that produces progesterone, a steroid hormone needed for pregnancy. It is a heterogenous gland containing many different cell types: small and large steroidogenic cells, endothelial cells, immune cells, and fibroblasts. At the end of a non-fecund reproductive cycle, the corpus luteum undergoes cyclic regression, a process which is divided into two processes: 1) functional regression, in which progesterone production rapidly declines and 2) structural regression, in which the tissue undergoes rapid remodeling into a fibrotic scar called a corpus albicans. Although fibroblasts are well-known for their role in tissue remodeling, very little …

Sensory Dysfunction And The Role Of Nrf2 In The Production Of Pain In Chronic Hindlimb Ischemia, Oliver Kitzerow

Theses & Dissertations

Peripheral arterial disease (PAD) is a progressive and debilitating atherothrombotic disorder that is estimated to impact >200 million people worldwide. Higher physical activity levels are associated with better overall survival rates, slower decline of functional capability, and improved quality of life. However, intermittent claudication, pain produced by physical activity, severely limits functional capacity in PAD patients. Despite known sensory dysfunction and documented neuropathy in diseased patients, the neural mechanisms that produce pain in PAD are yet to be identified. Importantly, few animal models of hindlimb ischemia (HLI) successfully recapitulate chronic human PAD. We developed a chronic animal model of HLI …

Cardiac Vagal Dysfunction And Ventricular Arrhythmogenesis In Type 2 Diabetes Mellitus After Myocardial Infarction, Dongze Zhang

Theses & Dissertations

Diabetes is the eighth leading cause of death in the United States. Every eight seconds a person dies from diabetes around the world. Among various types of diabetes, type 2 diabetes mellitus (T2DM) is the most common form, representing 90% to 95% of all diabetes populations. The leading cause of mortality and morbidity in T2DM patients is cardiovascular disease, among which acute myocardial infarction (MI)-induced ventricular arrhythmia is the major cause of death in T2DM. Patients with T2DM are two to four times more likely to die from MI than non-diabetic patients. Although well-known therapies including better glycemic control have …

Underlying Mechanism Of Ovarian Reserve Preservation From Gonadotoxicity, Yi Luan

Theses & Dissertations

Cancer therapies often lead to premature ovarian insufficiency by ovarian damage and follicle depletion. However, the oocyte death pathway induced by chemotherapies has been debated. Here we clarified the precise mechanism of ovarian depletion induced by cyclophosphamide and doxorubicin. Cyclophosphamide induced direct apoptosis in oocytes rather than overactivation of primordial follicles. Dormant oocytes instead of activated oocytes with high PI3K activity were more sensitive to cyclophosphamide. Although the ABL inhibitor, GNF2, has been proposed to ameliorate the apoptosis of primordial follicles against cyclophosphamide, GNF2 did not prevent the loss of primordial follicles induced by cyclophosphamide in the systems tested. Oocyte-specific …

Psychological Trauma Alters T-Lymphocyte Inflammation And Redox Through Sympathetic Mechanisms, Safwan K. Elkhatib

Theses & Dissertations

Posttraumatic stress disorder (PTSD) is a devastating psychiatric disorder characterized by distinctive symptom clusters, including intrusive memories (i.e., flashbacks), avoidance of related stimuli, affective changes, and hyperarousal. Strikingly, patients with PTSD face a significantly increased risk for a number of inflammation-driven pathologies, ranging from cardiovascular to autoimmune disease. Yet, the exact etiology of this increased risk remains unknown. The immune system is known to be strongly influenced by the sympathetic nervous system, and sympathetic overactivity is a hallmark of PTSD. Lymphoid organs, such as the spleen, are richly innervated by sympathetic nerve fibers which terminate near adaptive immune …

The Role Of Central Ace2 And Nrf2 In Sympatho-Excitation: Responses To Central Angiotensin Ii, Anyun Ma

Theses & Dissertations

Sympatho-excitation is a key characteristic in cardiovascular diseases such as chronic heart failure (CHF) and primary Hypertension (HTN). Evidence suggests that increased sympathetic tone is closely related to activation of the Renin-Angiotensin-Aldosterone system (RAAS) in the central nervous system. An underlying mechanism for sympatho-excitation is thought to be oxidative stress resulting from Angiotensin II (AngII) type 1 receptor (AT1R) activation. Over the past several decades, pharmacological targeting of components of the RAAS have been used as standard therapy in CHF and HTN. However, additional therapeutic strategies are necessary to control these diseases. Oxidative stress is regulated, in part, by the …

Role Of Eps15 Homology Domain-Containing Protein 4 (Ehd4) In The Kidney, Shamma Rahman

Theses & Dissertations

In the kidney, endocytic recycling regulates the abundance of channels and transporters in the membrane of the tubular epithelium, and thereby controls the kidney’s ability to regulate water homeostasis. In recent years, a family of proteins called Eps15 homology domain-containing (EHD) proteins has emerged as important regulators of the endocytic recycling pathway. Mammals express four paralogs of EHD proteins, EHD1-4, that are expressed in different tissues. Although EHD4 is expressed in the kidney, the specific physiological role of EHD4 in the kidney remains unknown. Therefore, this dissertation was focused to elucidate the physiological role of EHD4 in the kidney. In …

Target Validation And Pharmacological Characterization Of Novel Nmdar Modulators, Kiran Sapkota

Theses & Dissertations

The N-methyl-D aspartate receptors (NMDARs) are ligand-gated ion channels, which play important roles in learning and memory. Excessive activity of NMDARs is implicated in damage due to stroke and neurodegenerative diseases, whereas hypoactivity of NMDARs contributes to schizophrenia. The initial goal of my dissertation is to evaluate the potential role of the GluN2D-containing NMDARs in neuropathological, behavioral and cognitive alterations associated with schizophrenia and characterize the pharmacology and mechanisms of action of NMDAR modulators which could potentially be used to modulate these receptors in schizophrenia.

A subanesthetic dose of the NMDAR antagonist ketamine elicits symptoms of schizophrenia. This property led …

Molecular Mechanisms Of Necrotic Cell Death In Ischemic Renal Injury, Yuan Ying

Theses & Dissertations

Acute kidney injury is a common clinical syndrome particularly in hospitalized patients. Necrotic cell death, as one type of major cell death after ischemic reperfusion injury, is partially responsible for the rapid decline in GFR. p53 is a novel apoptosis and necrosis inducer and is found to be activated after ischemic renal injury. Although previous studies suggest that p53 could be an important mediator of kidney dysfunction, no studies have examined its role in necrotic cell death and the cross talk between p53 and other necrotic cell inducers such as PARP-1 and CypD. Thus, in this study our first goal …

Interaction Between Angiotensin Ii And Bdnf In Modulating Sympathetic Nerve Activity, Bryan K. Becker

Theses & Dissertations

Over activation of the sympathetic nervous system is prevalent in many forms of cardiovascular disease such as chronic heart failure (CHF) and hypertension. Although increased neuronal renin-angiotensin system activity in presympathetic neurons has been well implicated in mediating this sympatho-excitation, many of the neuronal effects of angiotensin II (Ang II) signaling remain poorly understood. One particular mechanism of Ang II-mediated increases in presympathetic neuronal activity is through reductions in voltage-gated K⁺ currents. Another pathway that has profound effects on neuronal K⁺ currents and that has been previously implicated in Ang II-signaling is brain-derived neurotrophic factor (BDNF) activity through …