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Browsing by Author "Gentile, Chris, committee member"

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    Investigating the effects of an endogenous and an exogenous oxidant stressor on protein synthesis in C2C12 myoblasts
    (Colorado State University. Libraries, 2015) Musci, Robert V., author; Miller, Benjamin, advisor; Hamilton, Karyn, advisor; Gentile, Chris, committee member
    Reactive oxygen species (ROS) related signaling is important for stress adaptation. Specifically, ROS may alter protein turnover in a duration dependent manner with acute ROS exposure increasing protein synthesis for cellular adaptation. In vitro experimentation remains a valuable tool investigate the mechanisms underlying ROS-mediated protein synthesis. This study investigates paraquat (PQ), a mitochondrial complex I inhibitor that induces superoxide production, as a potential candidate to induce endogenous ROS production in vitro to simulate an oxidative stress similar to in vivo conditions. We hypothesized that acute PQ treatment would induce protein synthesis in cells similar to exogenously added hydrogen peroxide (H₂O₂). We treated C2C12 myoblasts with 0, 1, or 2mM PQ or 0, 50, 100, or 500uM H₂O₂ for 4, 8, or 12 h while using 4% deuterium oxide enriched media to measure protein synthesis of mixed, cytosolic, and mitochondrial (mito) fractions. 100uM H₂O₂ and 2mM PQ transiently increased mito protein synthesis at 4h compared to control (H₂O₂: 0mM: 1.89%/hr +/- 0.068, 100uM: 2.75%/hr +/- 0.098 p<0.05; PQ: 0mM: 4.30%/hr +/- 0.33, 2mM: 6.86%/hr +/- 0.552, p<0.05). We verified that PQ induced oxidative stress by demonstrating that 2mM PQ 2mM PQ augmented HO-1 content compared to control at 12h (0mM: 0.452a.u. +/- 0.133, 2mM: 1.434a.u. +/- 0.487 p<0.05). Thus, we have developed an in vitro model that induces endogenous production of ROS to induce oxidative stress and demonstrates a ROS-mediated increase in mito protein synthesis.
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    Molecular and sociocultural exploration of sourdough: impacts on gluten sensitivity and bread characteristics
    (Colorado State University. Libraries, 2023) Clark, Caitlin, author; Van Buiten, Charlene, advisor; Stone, Martha, committee member; Weir, Tiffany, committee member; Gentile, Chris, committee member; Prenni, Jessica, committee member
    Sourdough is a bread product fermented by communities of wild bacteria and fungi known as a starter culture. Previous work has examined the effects of specific starter organisms on bread quality, but the relationships between whole microbiomes and dough/bread physicochemical properties are currently unknown. The objective of this study was to investigate the relationship between physicochemical properties of sourdough breads and the microbiomes of their starter cultures. Twenty sourdough starters with characterized microbiomes were used to produce wheat-based dough and bread. The chemical properties (pH, titratable acidity, free amino acids, Aw) of dough and physical properties (loaf volume, crust color, texture) of the breads were compared to a control fermented with baker's yeast. The degradation and toxicity of gliadin resulting from fermentation with the sourdough samples was also studied in vitro. Results indicate that sourdough-fermented breads produced under real-world conditions are distinct from yeast-fermented bread in terms of physicochemical parameters and proteolysis, which may exert downstream effects on the inflammatory capacity of gluten. We also investigated the beliefs and behaviors of gluten-sensitive sourdough consumers and professional sourdough bakers. We found that commercial sourdough is not reported to relieve gluten-mediated symptoms for consumers diagnosed with celiac disease (CD) or non-celiac gluten sensitivity (NCGS), but undiagnosed (UD) gluten-sensitive consumers may benefit from it. We also determined that sourdough bakers act as brokers of health advice in the gluten-sensitive community.
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    Physicochemical modification of gliadin by black tea polyphenols: insight towards a nutraceutical therapy for celiac disease
    (Colorado State University. Libraries, 2022) Mathews, Paul, author; Van Buiten, Charlene, advisor; Gentile, Chris, committee member; Chung, Jean, committee member
    Celiac disease is an autoimmune disorder that affects approximately 1% of the global population. The pathogenesis of celiac disease is complex, involving the innate and adaptive immune responses. Exposure to gluten amongst genetically susceptible individuals initiates and propagates the disease process, with autoimmunity against endogenous tissue-transglutaminase enzymes manifesting intra- and extra-intestinal symptoms. Currently, the only mitigation strategy for celiac disease is an adherence to a gluten-free diet, which can be difficult to maintain. Recent advances in synthetic and natural products chemistry may offer therapeutic alternatives to the total abstinence from gluten containing products. The overarching objective of our research is to develop a nutraceutical approach to treating celiac disease using dietary polyphenols from tea. Within this thesis, we used a multi-spectroscopic approach to show that black tea polyphenols, which are rich in theaflavins and other flavanols, interact with gluten proteins in vitro to form colloidal complexes that result in structural change to the protein. These changes have the potential to reduce the immunogenicity of gluten via interference with digestion, sequestration, and conformational changes which may reduce recognition of the protein by immune cells. The interactions investigated here offer promise as a nutraceutical, plant-based therapy to acute gluten exposure in susceptible individuals.
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    Sex differences in cortical-hypothalamic control of stress reactivity and cardiovascular susceptibility
    (Colorado State University. Libraries, 2023) Schaeuble, Derek, author; Myers, Brent, advisor; Chicco, Adam, committee member; Gentile, Chris, committee member; Tobet, Stu, committee member
    Major depressive disorder (MDD) is characterized by prolonged sadness and a loss of interest, and it impacts an estimated 21 million adults in the United States. The onset of MDD is multifactorial and rates of MDD have increased due to the psychosocial and economic factors associated COVID-19 pandemic. This poses a substantial threat to population health as MDD is projected to be the leading cause of disability by 2030. Even throughout the pandemic, cardiovascular disease (CVD) is still the highest mortality rate of any disease worldwide average of 17.9 million deaths per year. More importantly, MDD and CVD have devastating comorbidity that is poorly understood. MDD doubles the risk of developing cardiovascular disease and significantly increases the chance of morbidity following cardiovascular events. Thus, we need to address mental health disabilities and cardiovascular disease susceptibility. Interestingly, both diseases are exacerbated by chronic life stressors, which increase the prevalence of mood disorders and can alter sympathetic nervous activity increasing heart rate and blood pressure. Studying how stress affects the brain may yield important information on how to treat these two diseases. In this series of experiments, I examine how the ventral medial prefrontal cortex (vmPFC) alters stress responding through its downstream connections to provide a mechanism for MDD and cardiovascular disease comorbidity. I will provide a brief background of the structure and function of the vmPFC and describe how neurons from this region can alter stress responding through synapses in the hypothalamus. Chapter 2 is the first of a series of experiments where I show decreased activity of the vmPFC interacts with chronic stress to predispose male rats to cardiovascular disease susceptibility. Because mood disorders are more common in women and cardiovascular disease is more prevalent in post-menopausal women compared to men, chapter 3 examines whether activating vmPFC projection neurons is sufficient to influence behavior, stress responding, and cardiovascular activity in both sexes of rats. This work uncovered that output of vmPFC glutamate neurons has sexually divergent outcomes on neuroendocrine and autonomic cardiovascular responses to stress. Furthermore, it became evident that altered vmPFC activity predisposes males but not females to cardiovascular disease susceptibility. The vmPFC does not directly project to autonomic or neuroendocrine effector regions, so chapter 4 investigates whether the vmPFC is sufficient to control stress autonomic and neuroendocrine responding through downstream intermediary synapses. The intermediate region of interest is the posterior hypothalamus (PH) which can regulate endocrine and cardiovascular activity and receives dense innervation from the vmPFC. In chapter 5, I am exploring the necessity of this vmPFC-PH circuit to regulate cardiovascular activity and stress reactivity following chronic stress exposure. Altogether these data identify novel neurocircuitry linking stress exposure to cardiovascular disease risk.
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    The role of the erythrocyte and subsequent ATP release in blood flow and oxygen delivery to the human forearm during hypoxic exercise
    (Colorado State University. Libraries, 2014) Mossing, Allison Marie, author; Dinenno, Frank, advisor; Chicco, Adam, committee member; Gentile, Chris, committee member
    Hypoxia and exercise each cause ATP to be released from the erythrocyte, increasing vasodilation to match the blood flow and oxygen demands of the exercising skeletal muscle tissue (Bergfeld & Forrester, 1992; Ellsworth, 2004; Gonzalez-Alonso, Olsen, & Saltin, 2002). However, few studies have examined the extent to which ATP can be released from the erythrocyte, especially due to hypoxic exercise. We hypothesized that hypoxic exercise would cause further augmentation in erythrocyte-derived ATP release, vasodilation, and blood flow. To test this hypothesis, in 10 healthy young adults, blood samples were taken from a deep venous catheter inserted into the experimental arm and analyzed to determine and compare the amount of ATP released under normoxic and then hypoxic exercise. Forearm blood flow (FBF; Doppler ultrasound) and vascular conductance (FVC) responses to submaximal rhythmic forearm handgrip exercise (15% maximal voluntary contraction) in normoxia and during systemic hypoxia (80% arterial oxygen saturation; pulse oximetry) were measured and calculated, respectively. Compared to normoxic rest, 3 minutes of normoxic exercise significantly increased plasma ATP (45±4 nmol/L vs 101±22 nmol/L; P<0.05). Plasma ATP with hypoxic exercise was only significantly greater than normoxic rest at 30 seconds (114±4 nmol/L; P<0.05) and 3 minutes (84±12 nmol/L; P<0.05) of exercise. ATP collected at any time point with 3 minutes of hypoxic exercise was not significantly greater than with 3 minutes of normoxic exercise (P=NS). Forearm blood flow 3 minutes of hypoxic exercise (250±26 ml min-1; P<0.05) were both greater than with normoxic exercise (201±21 ml min-1; P<0.05) or normoxic rest (29±4 ml min-1; P<0.05). Forearm vascular conductance was greater with hypoxic exercise (257±29 ml min1 (100mmHg) -1; P<0.05) than with normoxic exercise (212±23 ml min-1(100mmHg) -1; P<0.05) or normoxic rest (33±4 ml min-1(100mmHg) -1; P<0.05). As plasma ATP did not continually increase with hypoxic exercise, we conclude that hypoxic exercise may not be a strong enough stimulus for erythrocyte-derived ATP release. Despite a lack in ATP release, FBF and FVC were still maintained, suggesting that ATP may not be as important for vasodilation, enhanced blood flow, and oxygen delivery to the skeletal muscle as previously thought. Other factors involved in vasodilation and blood flow augmentation during hypoxic exercise warrant further investigation.