Nnedi Osuji (MS/Biomed ’21) completed her undergraduate degree at Temple University
where she received a bachelor of science degree in biology. Currently, Ms. Osuji is
in the second year of her Master of Science degree program and she has chosen a biomedical research concentration. In the first year of the master’s program, Ms. Osuji began working as a work study
research lab assistant in the cardiovascular development research lab of Dr. Cathy Hatcher who is an Associate Professor of Physiology. That experience encouraged Ms. Osuji
to pursue the second-year research concentration of the master’s degree program where
she focuses on cardiovascular research.
Disruptions that occur during normal cardiovascular development lead to the formation of congenital heart defects. Approximately 1% of all infants worldwide are born with heart abnormalities and some of these defects will affect the coronary blood vessels of the heart. I am investigating the expression of protein-coding gene transcripts that may be altered in these infants that are born with heart abnormalities. Previously, Dr. Hatcher’s lab identified the importance of the TBX5 transcription factor to heart development in mammals. Her lab developed a transgenic mouse model with a Tbx5 deletion, and the mouse exhibited signs of abnormal heart development including delayed formation of the outermost layer of cells of the heart, or the epicardium, and impaired formation of the coronary blood vessels that supply the cardiac muscle with much needed oxygen and nutrients. Both of these cardiovascular structures are derived from a common progenitor, the proepicardium, and Tbx5 is expressed here during cardiovascular development. A closer examination of hearts from these Tbx5-deficient mice revealed reduced cardiac expression of the gene encoding the adherents junction associated protein 1, or Ajap1.
Former students in the Hatcher lab discovered that silencing of the AJAP1 gene in primary cultured human epithelial cells led to an increased adhesion of these cells to underlying matrices and reduced their ability to migrate. In addition, expression of several transcripts was, potentially, altered in these AJAP1-silenced cells that were not altered in control cells. These types of cell behavior and changes in gene expression are likely to affect how blood vessels are formed in the heart. The goal of my research project is to dive deeper into this data in order to quantify and further select gene transcripts whose expression appears to be altered. In addition, I am conducting this project to validate and identify candidate transcripts in the TBX5-AJAP1 molecular pathway through a combination of in-person and virtual analyses.
When I started my work study job I knew both professors and students that were involved in research projects, but I specifically wanted to join this lab and focus on congenital heart defects. I am interested in cardiovascular medicine and children’s health. I knew this was a research project that would be of interest to me, so I selected this area of research for my second-year concentration.
I am identifying transcripts that have novel interactions with AJAP1 in epithelial cells that contribute to formation of the epicardial layer of the heart. First, I will analyze and validate altered expression of these transcripts in response to silencing of the AJAP1 gene. This is being conducted by quantitative polymerase chain reaction (qPCR) analysis. Second, I will analyze the TBX5-AJAP1-induced molecular pathway of candidate transcripts using a web-based prediction software. This software uses algorithms publication databases to predict potential associations between sets of genes and how those associations can impact cell behaviors. Third, I will work collaboratively with other work study students in the Hatcher lab to quantify the amount of AJAP1 protein that is reduced following silencing of the AJAP1 gene in our primary cultures of human epithelial cells. This will be carried out through western blot analysis of AJAP1 protein expression.
Congenital heart defects (CHDs) are the most common type of birth defect worldwide. These defects impact the lives of patients for the rest of their life and place them at a higher risk for developing cardiovascular disease. The overall goal of our lab is to develop a better understanding of why congenital heart defects occur, what can be done to prevent them, and identify tailored approaches to treat those individuals so they may have healthier outcomes.
Learn more about student research at PCOM.
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