2007 — 2011 |
Connelly, Jessica J |
K99Activity Code Description: To support the initial phase of a Career/Research Transition award program that provides 1-2 years of mentored support for highly motivated, advanced postdoctoral research scientists. R00Activity Code Description: To support the second phase of a Career/Research Transition award program that provides 1 -3 years of independent research support (R00) contingent on securing an independent research position. Award recipients will be expected to compete successfully for independent R01 support from the NIH during the R00 research transition award period. |
Molecular Dissection of Cardiovascular Disease: From Genes to Models to Function
Type II topoisomerases are essential enzymes common to all organisms. Their cellular functions include maintaining the levels of chromosome compaction and ensuring proper segregation at cell division. In addition they are often used as targets for antimicrobial agents and anticancer drugs. Understanding the process by which topoisomerase II (topo II) simplifies the topological complexity of its DMA substrate is of key importance. By a cut-and-paste mechanism, which is well understood at the molecular level, topo II is able to pass a DMA segment through another. How topo II recognizes the two DMA segments is still unclear. Topo II is known to unknot and decatenate DMA to levels below those expected by random strand-passage. These and other experimental observations suggest a chirality-driven non-random mechanism of topo II action. Numerous experimental and theoretical studies have addressed these questions. However a clear picture of the mechanism of topo II is still lacking. Our long-term goal is to find an accurate model for the mechanism of topology simplification by topo II. We here focus on the process of DNA unknotting. Our objective is to verify whether topo II has the ability to unknot DMA in the smallest possible number of strand-passages, or whether a chirality bias combined with other local information are sufficient to reach the experimentally observed unknotting levels. We propose an interdisciplinary approach involving a sophisticated theoretical framework based on mathematical knot theory and Monte Carlo computer simulations, and followed by experimental validation. The computer implementation is based on a novel idea which will greatly reduce computation time as compared to other computational models of unknotting. Relevance to Public Health: Our method will give us the ability to efficiently simulate wild-type topo II on any distribution of DNA knots. Besides being of theoretical interest, such modeling is relevant to public health. Unknotting assays are used in the design of anti-cancer drugs to identify new topo II inhibitors. Our work will be applied to quantifying the unknotting capabilities of the topo II of a given organism with and without the presence of an inhibitor, thus establishing a precise measure of the inhibitor's effectiveness.
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0.97 |
2009 — 2012 |
Connelly, Jessica J |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Epigenomics of Atherosclerosis
Abstract As our understanding of the intricate mechanisms of gene regulation increases, it is apparent that traditional methods of identifying aberrant genetic mechanisms associated with complex disease, such as linkage and association studies, will not be sufficient. Additionally, the traditional paradigm that variants that lead to disease must exist within the coding region of a gene needs to be changed. One step in better modeling of disease risk and understanding disease variants lies in expanding the paradigm of complex disease study to include epigenetic influences that contribute to diseases. We hypothesize that changes in DNA methylation status of genes in endothelial cells (ECs) and smooth muscle cells (SMCs) undergoing phenotypic switching, a hallmark of atherosclerosis formation, could play a role in atherosclerosis initiation and progression. This proposal specifically seeks to create comprehensive maps of the cytosine methylated genome in (1) ECs and SMCs under a disease and (2) non-disease state influenced using a novel and validated human surrogate vascular co-culture model that can recalibrate the EC and SMC phenotype into a healthy or atheroprone phenotype outside the human body and (3) diseased and non-diseased human aorta tissue. We tackle three paradigms to demonstrate how to evaluate cytosine methylation changes, in healthy cells and tissues, in disease cells and tissues, and in early (flow phenotype) and late (lipid and plaque laden tissue) atherosclerosis. In addition, highthroughput sequencing methods and tools will be developed using these data and be made available to all scientists.
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0.946 |
2019 — 2021 |
Carter, Carol Sue (co-PI) [⬀] Connelly, Jessica J |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Mechanisms of Maternal Brain Changes With Birth Interventions
ABSTRACT: The use of birth interventions, such as induction or augmentation of labor with exogenous oxytocin or surgical delivery via cesarean section, have risen sharply in the past 30 years. These interventions have contributed to a decline in maternal and infant mortality, but the long-term consequences for the mother are not well understood. High levels of exogenous oxytocin during birth dramatically downregulate the oxytocin receptor in the uterus. The role the receptor plays in shaping oxytocin activity in the maternal brain is unknown. Emerging research has begun to link these birth interventions to maternal mental health and specifically to postpartum depression. Postpartum depression is prevalent in as many as 1 in 5 new mothers, yet we know little about the underlying biology of this disorder. Several risk factors have been identified, including changes in circulating levels of oxytocin and epigenetic modification of the oxytocin receptor gene, OXTR. The common use of exogenous oxytocin during birth may have long-term consequences for oxytocin functioning via OXTR epigenetic pathways and, in turn, contribute to the oxytocin system dysfunction that increases risk for postpartum depression. We propose to explore the link between birth intervention, changes in epigenetic markers on OXTR, and maternal behavior in the highly social prairie vole with three specific objectives: (1) to refine a new translational animal paradigm designed to model and study selected features of human birth practices, (2) to test the hypotheses that altered oxytocin levels at birth, whether through labor induction or cesarean section, will influence the behavior and brain of the mother via epigenetic effects on OXTR, and (3) to gain a deeper knowledge of mechanisms through which birth-related interventions may have lasting functional and epigenetic consequences for the mother. We will focus on altered epigenetic regulation of OXTR given the link between the oxytocin receptor, birth interventions, and postpartum depression. The natural pattern of OXTR DNA methylation, hydroxymethylation, and gene transcription will be characterized across gestation and following vaginal birth to gain insight into epigenetic mechanisms that shape the maternal brain in response to a natural, unmanipulated birth experience. Using exogenous oxytocin administration just prior to birth to model induction of labor in women, these same epigenetic markers will be examined in central and peripheral tissues to investigate how a birth with higher levels of oxytocin can alter long-term OXTR functioning and maternal behavior in new mothers. Cesarean delivery will also be used to examine behavioral and epigenetic consequences of opposing birth experiences, or those without pulsatile release of oxytocin during labor. The proposed experiments seek to develop a more complete animal model of maternal oxytocin system functioning following the birth experience, particularly epigenetic control of the receptor gene by DNA methylation and hydroxymethylation. These experiments will provide valuable information on how pregnancy, birth, and common birth interventions effect functioning of oxytocin pathways to shape the maternal brain.
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0.946 |