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Yang Xia, M.D., Ph.D. 1992, Hunan Medical University The University of Texas Health Science Center at Houston |
Research Interests:
Cardiovascular disease is the number one cause of morbidity and mortality in the United States. Therefore, understanding the molecular mechanisms underlying these diseases is crucial for identifying new therapeutic targets and developing rational pharmacological approaches to treat these life-threatening diseases at an early stage. The focus of my laboratory is to identify the signaling pathways that control pathophysiology of cardiovascular diseases. Three projects are currently under investigation.
Signaling pathways controlling cardiac hypertrophy : Cardiac hypertrophy is an early adaptive process that allows the heart to maintain or increase cardiac output in response to increased workload. We are interested in using both cellular systems and transgenic mice as our experimental methods to investigate the essential role of multiple signaling pathways in cardiac hypertrophy. Our current studies involve the analysis of mitogen activating protein kinase (MAPK) cascades in calcineurin signaling and mTOR signaling in cardiac hypertrophy.
Angiotensin receptor autoantibodies and the pathophysiology role in preeclampsia: Preeclampsia (PE) affects approximately 8% of all pregnancies, has been extensively studied, yet remains poorly understood. It is the leading cause of death due to pregnancy. The only effective treatment is delivery of the fetus and placenta, often resulting in serious complications of prematurity for the neonates. Recent studies from our laboratory indicate that the persistent presence of angiotensin AT1 receptor agonistic autoantibodies (herein termed AT1-AA) are a risk factor for the onset and development of PE. Therefore, our long-range goal is to evaluate the contributions of AT1-AA to PE and explore the immunological origins of these autoantibodies . AT1-AA has the ability to explain many features of this complex life threatening condition and immediately suggests diagnostic and therapeutic opportunities.
mTOR, a placental growth signaling sensor: A major cell type controlling the development of the placenta is the trophoblast. These cells originate from the trophectoderm and are the first cell lineage established during mammalian development. The proliferation and differentiation of trophoblast cells is under the control of a variety of hormones and growth factors and is influenced by nutrient availability. The intracellular signaling pathways acting downstream of these mitogenic factors and nutrients to regulate trophoblast proliferation and placental development are poorly understood. We showed that metabolites of the GFAT (glutamine fructose amidotransferase) reaction act upstream of mTOR and function as a nutrient sensor to regulate trophoblast cell proliferation in response to glucose. Overall our studies show that growth factor and nutrient signaling converge at tuberin, an upstream regulator of mTOR and that mTOR functions as an important placental growth signaling sensor. Therefore, our current research is focus on determining the regulatory role of GFAT metabolites on mTOR signaling as nutrient sensors for normal and abnormal trophoblast trophoblast cell proliferation (such as diabetic gestation, and intrauterine fetal growth retardation).
During a tutorial in my laboratory, the student will be exposed to various molecular and cell biology techniques such as transfection, DNA/RNA manipulation, RT-PCR, in vitro transcription and translation assays, western blot analysis and immunoprecipitation. The student may also learn how to identify and characterize the transgenic mice.
Program Affiliation:
Program in Biochemistry and Molecular Biology