Project Title: Role of Histone Methylation in PS1 Transcription: Implication in Alzheimer's Disease
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| Presenilin-1 (PSI) protein is involved in a variety of critical physiological processes including embryogenesis, CNS development, cell death, and the pathogenesis of Alzheimer's disease (AD). PS1 influences mammalian development and neuronal apoptosis by controlling the proteolytic cleavage of Notch 1 receptor, and also causes the pathogenesis of early-onset AD (FAD) by altering the processing of betaamyloid precursor protein (APP). Thus, PSI gene regulation plays a crucial role in controlling these events. Covalent modifications of histone tails by methylation control regulation of gene transcription. However, we do not yet understand the precise regulatory mechanisms by which methylation of histones controls the transcription of the PS 1 gene, and in the absence of that information it has been difficult to target the PSI gene locus in designing therapies to control mammalian development and AD. The experiments proposed in this application will elucidate the regulatory roles of histone methylation in PSI transcription. A secondary aim of this proposal tests the hypothesis that histone methylases cause histone methylation to control PSI transcription. These experiments are important because PSI expression is linked to (i) Notch 1 mediated cell fate decision during development, (ii) neuronal apoptosis during aging, and (iii) pathogenesis of FAD and AD. The proposed specific aims are to (1) elucidate histone methylation pattern in the PS1 gene in undifferentiated and differentiated neuroblastoma cells, and (2) investigate histone methylation pattern in the post-mortem brain tissues of AD patients and non-demented controls. Roles of methylation of histones in PSI transcription will be studied using chromatin immunoprecipitation, imrnunohistochemistry, in situ hybridization, and siRNA technology. These experiments will provide detailed analysis of mechanisms of the regulation of PSI transcription by methylation of histones that are likely to be involved in mammalian development and the pathogenesis of FAD and AD. |
Project Title: In Vitro Studies of Prostate Cancer Cell Adhesion to the Endothelium and the Role of Hypoxia Inducible Factor.
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| Metastasis caused by cancer cells that enter the circulation and travel to distant sites in the body is the primary cause for mortality in cancer patients. Although many studies determined the mechanism of initial attachment and arrest of cancer cells onto endothelial cells, only a limited number of studies investigated cancer cell-endothelial cell interaction under physiological flow conditions which more closely resemble adhesion of cancer cells in circulation. Hypoxia inducible factor (HIF) is an important transcription factor which promotes tumor growth through the induction of angiogenesis and the activation of anaerobic metabolism during hypoxia. Furthermore, tumor hypoxia is clinically correlated with increased metastatic potential.HlF-la protein expression was detected in hypoxic human prostate cancer cell lines (PC-3 and DU-145) and in the majority of prostate carcinomas, and plays an important role in prostate cancer progression. Recent studies uncover a new role of HIF-1 which regulates cell adhesion and migration. The central hvpothesis of this proposal is that HIF-1 plays an important role in prostate cancer cell adhesion to endothelium, facilitating metastasis. The long-term uoal of this proposal is to develop and establish a novel technology to investigate the interaction between cancer cells and endothelial cells under physiological flow conditions and to elucidate the role of hypoxia inducible factor (HIF) in the metastasis of prostate cancer cells. The specific aims of this proposal are: 1. Investigate the adhesion of prostate cancer cells to the endothelium under physiological flow conditions. (by Dr. Nguyen's group) 2. Determine the mechanism of HIF-1 in prostate cancer cell adhesion to the endothelium. (by Dr. Kim's group) This is a highly collaborative project that involves the necessary expertise of the faculty in both campuses, UNT and UTA to complete the proposed project: Dr. Kim at UNTHSC with expertise in molecular biology and research experience in prostate cancer and HIF, whereas Dr. Nguyen at UTA with expertise in biomechanics and cellular engineering and research experience in the endothelium and in vitro flow systems. Moreover, Dr. Nguyen's group developed the parallel plate flow chamber systems which mimic the physiological blood flow conditions similar to those in vivo. The innovative aspect of this proposal is to use the novel in vitro flow system which mimics blood flow in circulation in vivo to investigate dynamic process of tumor cell adhesion to vascular endothelium under flow conditions and to use GeneChip microarray technology to identify genes regulated by HIF-1. The successful outcome of this study will shed lights on understanding the mechanism and molecules involved in dynamic process of cancer cell adhesion, which can be used as a potential target(s) in cancer therapy. |
Project Title: Microcirculatory Dysfunction: Potential Therapeutic Target of Estrogen Against Ischemic Stroke.
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| Stroke is the leading cause of neurological deficit and the third leading cause of death in the U.S., but currently there is no effectively treatment. Ischemic stroke results from an obstruction of cerebral arteries and accounts for about 83% of total stroke. The blocking of the cerebral artery can lead to vasospasm. Currently, the role of vasospasm in ischemic stroke is unclear and less studied. The recognition of vasospasm is essential both for the understanding and the treatment of ischemic stroke. Near infrared spectroscopy (NIRS) is a noninvasive technique deriving information about the concentrations and the oxygenation of hemoglobin (Hb) from the measurements of light backscattered from the brain. NIRS technology allows detecting features of the hemodynamic response of cerebral microvasculature to physiological stimuli and pathological insults. In our preliminary study, we identified the microvasculature dysfunction in a cerebral ischemia model characterized as increase of low frequency fluctuation of the relative change of oxy-hemoglobin concentration (AIHbOn]). Further, the ischemia induced cerebral microvasculature dysfunction was significantly improved upon treatment of 17p-estradiol. In the present proposal, we hypothesized that the ischemia induced cerebral microvasculature dysfunction, identified by NIRS, was attributed to vasospasm. The ischemia induced cerebral microvasculature dysfunction will be further characterized and the effects of a non-feminizing estrogen analogue on the microvasculature dysfunction will be determined. This application is a novel interaction between Department of Pharmacology and Neuroscience of UNTHSC and Department of Biomedical Engineering of UTA. Upon the progress of the present project, a novel method to monitor cerebral vasospasm will be developed and the potential of targeting cerebral vasospasm for treatment of ischemic stroke will be evaluated. |
Project Title: Novel Approach to Measurement of Hot Flashes by Near Infrared Spectroscopy
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| It is estimated that during the reproductive aging, approximately 65% to 80% of women experience hot flashes, and during the next five decades, 27 to 37 million American women may suffer from menopausal hot flashes. The perception of hot flashes may start with increased blood flow to the extremities, increased heart rate, and anxiety. Hot flashes can last from a few seconds to more than an hour, and persist for one year or up to five years. Despite their detrimental impact on quality of life, hot flashes have not been well represented in research studies. The main reason is the lack of reliable, wellcharacterized, universally accepted standard instruments and methods to collect data on hot flashes. Recently, the Menopausal Vasomotor Symptoms (MVS) survey - a new instrument for subjective assessment of hot flashes - was developed in our clinical research laboratory. An in-depth, brief, reliable, and standardized subjective assessment of multiple dimensions of hot flashes can be performed with the MVS survey. For the objective measurement of hot flashes, only one instrument is currently available; it records changes in skin conductance during hot flashes. These measures may be falsenegative because skin conductance may fluctuate with changes in body hydration and sweating during hot flashes. A hot flash is clearly a vasomotor symptom strongly associated with increased blood flow, therefore primary objective measures of hot flashes should be based on changes in blood flow or blood volume. The near-infrared spectroscopy (NIRS) offers a novel and alternative approach for objective monitoring of hot flashes based on changes in blood volume. Our recent preliminary study has demonstrated that NlRS can be an efficient, real-time, non-invasive method to monitor vasomotor changes in menopausal women. No study has been done to demonstrate the suitability of the NlRS for measures of hot flashes. The proposed research project will focus on the following specific aims: Aim 1: Monitor hot flashes using simultaneously two objective methods - the novel NlRS device based on blood volume changes and the standard skin conductance monitoring instrument. Aim 2: Obtain self-reported measures of hot flashes using the MVS survey. Aim 3: Analyze correlations between the subjective and objective data and analyze validity and reliability of the novel NlRS instrument as an objective measurement of hot flashes. The results from this project will provide a pool of data needed to improve our NIH application on further development of the NlRS instrument as a Wireless Optical Monitoring and ANalysis (WOMAN) device for objective ambulatory recording of hot flashes. |