Featured Researcher
Targeting RAGE at the DNA Level to Combat Atherosclerosis
Edem Nuglozeh, PhD, Associate Research Scientist in the Division of Surgical Science, is an expert in engineering genetically modified mice, including knockout and transgenic mice.
A vascular biologist trained in molecular genetics, he is a member of a team of researchers in the Division that is investigating molecular mechanisms of vascular inflammation—now believed to lead to devastating conditions such as atherosclerosis, kidney failure and wound-healing problems, among others.
The team's work centers around investigations of RAGE (receptor for advanced glycation end-products), a cell-surface molecule present in vascular tissues throughout the body that, when activated, unleashes a cascade of destructive inflammatory processes.
Dr. Nuglozeh, who arrived at Columbia in mid-2006, is developing multiple lines of mice using a site-specific gene recombination system known as lox-cre.
Lox-cre enables the scientist to remove a gene in a specific tissue. Funded by an NIH grant in 2006, his work focuses on atherosclerosis (hardening of the arteries), a genetically complex disease that develops with diabetes and age.
In one of his mouse lines, Dr. Nuglozeh is silencing the RAGE gene in a tissue-targeted manner, so that RAGE may be deleted, for example, specifically in endothelial cells (the endothelium is tissue inside the vessels that comes into direct contact with the blood) or immune cells.
To accomplish this, he:
- modified a selected gene in mouse stem cells, placing a non-mammalian DNA sequence called loxP at both ends of the gene's sequence;
- introduced the engineered DNA into mouse stem cells which he in turn introduced into mouse ova, creating offspring with loxP surrounding every copy of the selected gene;
- once the offspring are available, he will mate them with another set of transgenic mice expressing Cre-recombinase in specific tissues (by tissue-targeted promoters).
The result is expected to be a mouse line that in which RAGE deletion will be accomplished in specific cells.
This approach will allow the team to decipher the problematic underlying RAGE and the vascular and immune systems in the development of atherosclerosis.
To better understand the contribution of the immune system in the development of atherosclerosis, Dr. Nuglozeh created a mouse line in which RAGE signaling is silenced in dentritic cells (which are antigen-presenting cells). The resulting animals can now be tested to see if they develop atherosclerosis when fed a high fat diet.
"If we hypothesize that RAGE is a cause of [atherosclerotic] inflammation," he says, "the genetic model, and the role of dendritic cell RAGE, will show if that hypothesis is true."
In addition to removing genes, Dr. Nuglozeh is able to utilize a transgenesis technique to enhance the activity of a gene that is a downstream effecter of RAGE. He has used this technique to create a mouse line over-expressing a gene called CTGF, in order to explore that gene's role in atherosclerotic plaque.
So far, he has used the gene-targeting approach to create four genetically altered animals for the purpose of studying atherosclerosis.
He is also designing other animals using a more effective and powerful technology termed BAC (bacterial artificial chromosome) engineering.
The larger picture that is emerging from Dr. Nuglozeh's research is of a single disease—atherosclerosis—created by multiple genes. He envisions a day when the treatment of atherosclerosis will be an individually tailored drug cocktail that would target and repair a patient's endothelium dysfunction.
But for now, he speaks with a scientist's cautious circumspection, "Molecular biologists don't jump to conclusions.
We have to keep seeking a better model of a disease and its treatment," he says.
"Two to three years from now, the lab will flourish with these multiple animals.
The mice will provide the information we need."
Dr. Nuglozeh, whose passion is vascular biology, appears to have applied his scientist's watch-and-wait patience to his professional life.
After completing a Ph.D. in molecular biology in 1996 focusing on vascular biology and hypertension at the University of Montreal, he did not immediately find a job in his field.
Later, while working as an osteoporosis investigator at Temple University Medical School in Philadelphia during 2001-2006, his focus on vascular biology had not flagged: Noting that a gene called CTGF, involved in bone development, seemed to play a role in atherosclerosis, he engineered a mouse model of that gene's overexpression.
When he was hired for the vascular-focused investigations of the Division of Surgical Science, Dr. Nuglozeh knew he had gotten back on his true career path.
"We may get off track in the beginning, but come back to it," he says philosophically.
Dr. Nuglozeh is enthusiastic about the prospects of fruitful and stimulating collaboration with his colleagues at Columbia, and he looks forward to the exciting challenges that lie ahead.
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