Matching Items (44)
Description
Premature babies are at risk of death from immature lung development. For this reason, pregnant mothers at risk for preterm delivery are administered dexamethasone (DEX), a synthetic glucocorticoid that promotes fetal lung development. However, exposure to DEX in utero is associated with low birth weight and cardiovascular development pathologies. Moreover, our lab found that DEX administration in-utero leads to a sex-specific increase in stress-induced tachycardia in female, but not male offspring. This project seeks to expand on this preliminary finding of the heart by examining local effectors of activity from the sympathetic system (tyrosine hydroxylase and catechol-o-methyltransferase). Tyrosine hydroxylase was measured as it catalyzes the rate limiting step of norepinephrine synthesis while catechol-O- methyltransferase was studied as it catalyzes the degradation of norepinephrine. Acetylcholinesterase was used to measure parasympathetic activity as it catalyzes the degradation of the primary neurotransmitter of the parasympathetic nervous system, acetylcholine. Analyses of sympathetic as well as parasympathetic activity were done to determine influences of in-utero DEX exposure on autonomic regulation in adulthood. Pregnant rats were administered DEX (0.4 mg/kg, i.p.) or vehicle (20% w/v 2-hydroxypropyl ß- cyclodextran) at gestation days 18-21, with euthanasia of offspring occurring at around the time the offspring reached 13-15 weeks of age. Left ventricles and right atria were pulverized, processed and subjected to western blot analysis to determine expression of proteins of interest. Males exposed to DEX in-utero saw a decrease in tyrosine hydroxylase expression in left ventricle and right atrium when compared to vehicle control, a difference not seen with females. In addition, catechol-o-methyltransferase expression was increased in right atria from male, but not female rats. Acetylcholinesterase expression was reduced in the right atria of female, but not male rats. The present findings suggest reduced norepinephrine signaling in the heart of male, but not female DEX-exposed offspring. Given that we have previously found that female, but not male rats exhibit exaggerated stress-induced tachycardia, our current findings suggest that males possess a sex-specific compensatory mechanism allowing the heart to resist increased sympathetic signaling from the brain, one that females do not possess. The underlying mechanics of this proposed mechanism are unclear, and further investigation is needed in this subject to determine the significance of the findings from our study.
ContributorsSharma, Arpan (Author) / Conrad, Cheryl (Thesis director) / Hale, Taben (Committee member) / Department of Psychology (Contributor) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
Description
Systemic lupus erytematosus (SLE) is an autoimmune disease where the immune system is reactive to self antigens resulting in manifestations like glomerulonephritis and arthritis. The immune system also affects the central nervous system (known as CNS-SLE) leading to neuropsychiatric manifestations such as depression, cognitive impairment, psychosis and seizures. A subset of pathogenic brain-reactive autoantibodies (BRAA) is hypothesized to bind to integral membrane brain proteins, affecting their function, leading to CNS-SLE. I have tested this BRAA hypothesis, using our lupus-mouse model the MRL/lpr mice, and have found it to be a reasonable explanation for some of the manifestations of CNS-SLE. Even when the MRL/lpr had a reduced autoimmune phenotype, their low BRAA sera levels correlated with CNS involvement. The correlation existed between BRAA levels to integral membrane protein and depressive-like behavior. These results were the first to show a correlation between behavioral changes and BRAA levels from brain membrane antigen as oppose to cultured neuronal cells. More accurate means of predicting and diagnosing lupus and CNS-SLE is necessary. Using microarray technology I was able to determine peptide sets that could be predictive and diagnostic of lupus and each specific CNS manifestation. To knowledge no test currently exists that can effectively diagnose lupus and distinguish between each CNS manifestations. Using the peptide sets, I was able to determine possible natural protein biomarkers for each set as well as for five monoclonal BRAA from one MRL/lpr. These biomarkers can provide specific targets for therapy depending on the manifestation. It was necessary to investigate how these BRAA enter the brain. I hypothesized that substance P plays a role in altering the blood-brain barrier (BBB) allowing these BRAA to enter and affect brain function, when bound to its neurokinin-1 receptor (NK-1R). Western blotting results revealed an increase in the levels of NK-1R in the brain of the MRL/lpr compared to the MRL/mp. These MRL/lpr with increased levels of both NK-1R and BRAA displayed CNS dysfunction. Together, these results demonstrate that NK-1R may play a role in CNS manifestations. Overall, the research conducted here, add to the role that BRAA are playing in CNS-lupus.
ContributorsWilliams, Stephanie (Author) / Hoffman, Steven A (Thesis advisor) / Conrad, Cheryl (Committee member) / Chen, Julian (Committee member) / Orchinik, Miles (Committee member) / Arizona State University (Publisher)
Created2011
Description
The maternal separation (MS) paradigm is an animal model of early life stress. Animals subjected to MS during the first two weeks of life display altered behavioral and neuroendocrinological stress responses as adults. MS also produces altered responsiveness to and self-administration (SA) of various drugs of abuse including cocaine, ethanol, opioids, and amphetamine. Methamphetamine (METH) causes great harm to both the individual user and to society; yet, no studies have examined the effects of MS on METH SA. This study was performed to examine the effects of MS on the acquisition of METH SA, extinction, and reinstatement of METH-seeking behavior in adulthood. Given the known influence of early life stress and drug exposure on epigenetic processes, group differences in levels of the epigenetic marker methyl CpG binding protein 2 (MeCP2) in the nucleus accumbens (NAc) core were also investigated. Long-Evans pups and dams were separated on postnatal days (PND) 2-14 for either 180 (MS180) or 15 min (MS15). Male offspring were allowed to acquire METH SA (0.05 mg/kg/infusion) in 15 2-hr daily sessions starting at PND67, followed by extinction training and cue-induced reinstatement of METH-seeking behavior. Rats were then assessed for MeCP2 levels in the NAc core by immunohistochemistry. The MS180 group self-administered significantly more METH and acquired SA earlier than the MS15 group. No group differences in extinction or cue-induced reinstatement were observed. MS15 rats had significantly elevated MeCP2-immunoreactive cells in the NAc core as compared to MS180 rats. Together, these data suggest that MS has lasting influences on METH SA as well as epigenetic processes in the brain reward circuitry.
ContributorsLewis, Candace (Author) / Olive, Micheal F (Thesis advisor) / Conrad, Cheryl (Committee member) / Neisewander, Janet (Committee member) / Arizona State University (Publisher)
Created2013
Description
Bexarotene is a commercially produced drug commonly known as Targetin presecribed to treat cutaneous T-cell lymphoma (CTCL). Bex mimics the actions of natural 9-cis retinoic acid in the body, which are derived from Vitamin A in the diet and boost the immune system. Bex has been shown to be effective in the treatment of multiple types of cancer, including lung cancer. However, the disadvantages of using Bex include increased instances of hypothyroidism and excessive concentrations of blood triglycerides. If an analog of Bex can be developed which retains high affinity RXR binding similar to the 9-cis retinoic acid while exhibiting less interference for heterodimerization pathways, it would be of great clinical significance in improving the quality of life for patients with CTCL. This thesis will detail the biological profiling of additional novel (Generation Two) analogs, which are currently in submission for publication, as well as that of Generation Three analogs. The results from these studies reveal that specific alterations in the core structure of the Bex "parent" compound structure can have dramatic effects in modifying the biological activity of RXR agonists.
ContributorsYang, Joanna (Author) / Jurutka, Peter (Thesis director) / Wagner, Carl (Committee member) / Hibler, Elizabeth (Committee member) / Barrett, The Honors College (Contributor)
Created2012-05
Description
Vitamin D, a bioactive lipid and essential nutrient, is obtained by humans through either endogenous synthesis in response to UV light exposure or via nutritional intake. Once activated to its hormonal form, vitamin D binds to and activates the nuclear vitamin D receptor (VDR). Activation of VDR is known to modulate gene transcription in vitamin D target tissues such as kidney, colon, and bone; however, less is known about the ability of VDR to respond to "nutritional modulators". One such potential VDR modulator is resveratrol, a plant-derived polyphenol and potent antioxidant nutrient that also functions as a chemopreventative. Resveratrol is known to activate sirtuin-1, a deacetylase enzyme with potential anti-aging properties. This study explores the potential for resveratrol, an anticancer nutraceutical, to upregulate VDR activity through its effector protein, sirtuin-1. Furthermore, due to its putative interactions with several intracellular signaling pathways, klotho has been proposed as an anti-aging protein and tumor suppressor gene, while the Wnt/β-catenin signaling pathway drives enhanced cellular proliferation leading to numerous types of cancers, especially colorectal neoplasia. Thus, the ability of klotho to cooperate with vitamin D to inhibit oncogenic β-catenin signaling was also analyzed. The experiments and resultant data presented in this thesis explore the potential role of VDR as a physiologically relevant nutritional sensor in human cells. This novel study reveals the importance of nutrient modulation of the VDR system by vitamin D and resveratrol and how this might represent a molecular mechanism that is responsible for the putative anti-cancer actions of vitamin D. Furthermore, this study enhances our understanding of how vitamin D/VDR and resveratrol interact with klotho and how this interaction affects β-catenin signaling to mitigate oncogenic growth and differentiation. This works demonstrates that the vitamin D hormone serves as a likely chemopreventive agent for various types of cancers through control of anti-oxidation and cellular proliferation pathways via its nuclear receptor. Our results also indicate the potential for resveratrol, an anticancer nutraceutical, to upregulate VDR activity through SIRT1. Furthermore, the novel data presented in this work illustrate that klotho, an anti-aging protein, cooperates with vitamin D to synergistically inhibit oncogenic β-catenin signaling. Ultimately, this study enhances our understating of the molecular pathways that underpin nutritional chemoprevention, and how modulation of these pathways via dietary intervention may lead to advances in public health strategies to eventually curb carcinogenesis.
ContributorsKhan, Zainab (Author) / Jurutka, Peter (Thesis director) / Hackney Price, Jennifer (Committee member) / School of Mathematical and Natural Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
Psoriasis is a skin disease that affects millions of individuals. Genetic risk factors for psoriasis include a common deletion of two late cornified envelope (LCE) genes (LCE3B and LCE3C) located within a cluster of genes expressed during epithelial differentiation and skin repair. It was previously discovered that treatment with 1,25-dihydroxyvitamin D3 (1,25D) or analogs thereof can improve psoriasis symptoms in many patients, but the molecular mechanisms for this action are largely unknown. Our laboratory previously showed that 1,25D as well as low affinity ligands for the vitamin D receptor (VDR), such as delphinidin and cyanidin, are capable of upregulating the remaining LCE3A, -3D, and -3E genes to potentially compensate for the loss of LCE3B and -3C in promoting skin repair. In the current study, DHA and curcumin were tested and found to also upregulate LCE3 transcripts in a dose-dependent manner. To investigate other potential target genes for 1,25D and DHA, we tested JunB, for which low or absent expression has been reported to cause or be associated with psoriatic lesions. Our experiments showed a trend for an upregulation of JunB mRNA after DHA treatment, potentially providing benefit for psoriasis patients. Although our hypothesis is that DHA functions as a vitamin D receptor ligand to mediate upregulation of JunB and LCE3 genes, other investigators have assumed that DHA actions in skin are mediated via PPAR isoforms. We therefore utilized a selective ligand for PPAR delta (GW501516) to determine whether PPAR delta, the primary PPAR isoform in keratinocytes, is a mediator of DHA-induced LCE3 gene activation. Although a modest upregulation of LCE3 genes was seen after treatment with GW501516, our findings are still consistent with DHA acting primarily as a VDR ligand. Our results not only provide additional information about the ability of VDR ligands to upregulate specific skin genes with relevance for skin repair, but also may help provide a molecular basis for testing improved treatments for mild to moderate psoriasis.
ContributorsKarrys, Amitis (Author) / Jurutka, Peter (Thesis director) / Whitfield, Kerr (Committee member) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
The diagnosis of irritable bowel syndrome (IBS) is currently based on symptomatic criteria that exclude other conditions affecting the gastrointestinal tract, such as celiac disease, food allergies, and infections. The absence of appropriate diagnostic and therapeutic approaches for IBS places a significant burden on the patient and the health care system due to direct and indirect costs of care. Limitations associated with the application of symptomatic criteria include inappropriate use and/or intrinsic limitations such as the population to which these criteria are applied. The lack of biomarkers specific for IBS, non-specific abdominal symptoms, and considerable variability in the disease course creates additional uncertainty during diagnosis. This project involved screening tissue samples from patients with verified IBS to identify gene expression-based biomarkers associated with IBS. Through validation of microarray gene chip data on the tissue samples using PCR, it was determined that a number of genes within the diseased IBS patient tissue samples were differentially expressed in comparison to the healthy subjects. These findings could potentially lead to the diagnosis of IBS on the basis of a genetic "fingerprint".
ContributorsHockley, Maryam (Author) / Jurutka, Peter (Thesis director) / Sandrin, Todd (Committee member) / Zhang, Lin (Committee member) / Barrett, The Honors College (Contributor) / School of Mathematical and Natural Sciences (Contributor)
Created2013-12
Description
The relevance of depression in the clinical realm is well known, as it is one of the most common mental disorders in the United States. Clinical depression is the leading cause of disease for women worldwide. The sex difference in depression and anxiety has guided the research of not just recent studies but older studies as well, supporting the theory that gonadal hormones are associated with the mechanisms of emotional cognition. The scientific literature points towards a clear correlative relationship between gonadal hormones, especially estrogens, and emotion regulation. This thesis investigates the neural pathways that have been indicated to regulate mood and anxiety. Currently, the research points to the hypothalamic-pituitary-adrenal axis, which regulates the stress response through its ultimate secretion of cortisol through the adrenal cortex, and its modulated response when exposed to higher levels of estrogen. Another mechanism that has been investigated is the interaction of estrogen and the serotonergic system, which is noteworthy because the serotonergic system is known for its importance in mood regulation. However, it is important to note that the research seeking to determine the neurobiological underpinnings of estrogen and the serotonergic system is not expansive. Future research should focus on determining the direct relationship between cortisol hypersecretion and estrogens, the specific neurobiological effects of serotonergic receptor subtypes on the antidepressant actions of estrogens, and the simultaneous effects of the stress and serotonergic systems on depressive symptoms.
ContributorsArroyo, Mariana (Author) / Bimonte-Nelson, Heather (Thesis director) / Jurutka, Peter (Committee member) / School of International Letters and Cultures (Contributor) / School of Social and Behavioral Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
Description
The longstanding issue of how much time it takes a particle to tunnel through quantum barriers is discussed; in particular, the phenomenon known as the Hartman effect is reviewed. A calculation of the dwell time for two successive rectangular barriers in the opaque limit is given and the result depends on the barrier widths and hence does not lead to superluminal tunneling or the Hartman effect.
ContributorsMcDonald, Scott (Author) / Davies, Paul (Thesis director) / Comfort, Joseph (Committee member) / McCartney, M. R. (Committee member) / Barrett, The Honors College (Contributor)
Created2009-05
Description
The significance of hormonal vitamin D in the numerous facets of health stresses the importance of elucidating the molecular mechanism(s) associated with 1,25D-VDR signaling modulators (e.g., resveratrol and sirtuin-1). Resveratrol (Res), a natural antioxidant, is a potent activator of NAD-dependent deacetylase sirtuin-1 (SIRT-1), an enzyme associated with longevity in animal models. This present study employed mammalian 2-hybrid (M2H) and vitamin D responsive element (VDRE)-based transcriptional assays to investigate the potential effects of Res and SIRT-1 on VDR signal transduction. Results from VDRE-based assays indicate that Res and SIRT-1 potentiate 1,25D-VDR activity via cell-and-promoter-specific pathways. In addition, 1,25D displacement experiments revealed an increase in VDR-bound radiolabeled 1,25D in the presence of Res, suggesting that Res may potentiate VDR transactivation by stimulating 1,25D binding. M2H assays in HEK293 cells were then utilized to assess levels of interaction between VDR and VDR comodulators, including RXR, SRC-1, and DRIP-205. Both Res and SIRT-1 increased the ability of VDR to associate with RXR; however, SRC-1 and DRIP-205 interactions were not enhanced. The activity of a novel, non-acetylatable VDR mutant, K413R, was probed revealing that K413R possesses amplified transactivation capacity over wild-type VDR. A SIRT-1 inhibitor, EX-527, was used to suppress endogenous SIRT-1, resulting in significantly decreased VDR transactivation. Finally, qPCR results in HEK293 cells revealed that the 1,25D-mediated induction of CYP24A1, an endogenous VDR target gene, was enhanced (85%) by SIRT-1 while Res increased CYP24A1 expression by 294%. The combination of 1,25D, SIRT-1, and Res amplified CYP24A1 expression by 326% over 1,25D, although this effect did not reach statistical significance when compared to the Res only treated group. We conclude that acetylation of VDR comprises a negative feedback loop that attenuates 1,25D-VDR signaling. This loop is suppressed by resveratrol/SIRT-1-catalyzed deacetylation of VDR, restoring VDR activity. The two compounds, 1,25-dihydroxyvitamin D (1,25D, vitamin D) and 5-hydroxytryptamine (5-HT, serotonin), have been proposed to play a significant role in abnormal social behavior associated with psychological conditions including autism spectrum disorders (ASDs) and depression; however, the mechanism underlying these associations has yet to be elucidated. Deficiencies in 1,25D or 5-HT have been linked to the increased incidence of ASDs. Thus, examining the modulation of genes involved in 5-HT biosynthesis, reuptake, and degradation is fundamental in linking low 1,25D levels to the increased incidence of psychiatric disorders. We propose that 1,25D regulates tryptophan hydroxylase-2 (TPH2), the initial and rate-limiting enzyme in the biosynthetic pathway of 5-HT. In order to evaluate the regulation of TPH2 in neuronal cells, three formulations of media were examined to optimize the cell culture conditions necessary for growth and morphology of embryonic rat medullary raphe (B14) serotonergic neurons. Next, quantitative real time-PCR (qPCR) was utilized to examine TPH2 expression in cultured human glioblastoma (U-87) cells and rat serotonergic neurons (B-14). Human TPH2 mRNA in U-87 cells was induced dose-dependently resulting in a 2.4-fold increase at 10 nM 1,25D. Strikingly, TPH2 mRNA in B-14 cells was observed to be 26- to 86-fold upregulated at 10 nM 1,25D; however, 1 nM and 100 nM 1,25D elicited significantly smaller inductions (8-fold and 1.2-fold, respectively).
ContributorsSabir, Marya Sabah (Author) / Jurutka, Peter (Thesis director) / Hackney Price, Jennifer (Committee member) / Sandrin, Todd R. (Committee member) / School of Molecular Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2015-12