Researcher examines how egg cell errors impact fertility, genetic issues

A microscopic structure in mammalian egg cells called a meiotic spindle has one crucial job—and during egg maturation, it has only a few hours to do it properly. What happens in those few hours has important implications for the health and viability of a pregnancy.

The work of researchers in the College of Arts and Sciences may improve our understanding and treatment of infertility, miscarriage, genetic disorders and other pregnancy complications. Ileana Márquez is a postdoctoral researcher in the Department of Physics. She studies the meiotic spindle alongside Colm Kelleher, assistant professor of physics and principal investigator on the project, "Oogenesis: Understanding Emergent Spindle Behavior in Mammalian Oocyte."

Chromosomes: Just right

The meiotic spindle is a tiny, machine-like organ made of protein fibers inside a developing egg. It acts as a sorting system so genetic information is correctly distributed to prepare egg cells for fertilization. This process is critical to ensure that each egg receives the right number of chromosomes; too many or too few can prevent an egg cell (oocyte) from maturing.

Extra or missing chromosomes are also a common cause of miscarriages and genetic disorders, and errors in egg cell maturation are a leading cause of infertility and pregnancy complications that increase with maternal age.

While the structure of a mammalian meiotic spindle is stable, its composition is not fixed, she says.

"Everything inside it is moving, organizing and rearranging. Its elements are being pulled and dragged. We study its functional properties as well as its physical attributes. Is it rigid or is it squishy? Does it have enough energy to meet the molecular requirements to do its job? Studying these things lets us gain more insight into egg cell development."

An error-prone process

The work is also important in an era when many women delay having children, according to Márquez. Fertility rates decrease with age, and even in young people, "this process is very prone to error. For women and also for men, so many things can affect fertility. We can try to address those issues by studying this spindle structure."

Márquez says her guiding vision is to better understand how the spindle functions as the "machinery" that guides cell maturation. She hopes her work will provide deeper insights into the spindle's chromosome-sorting functions and believes those discoveries could lead to new therapies or pharmaceutical applications for egg cells and human patients.

"We have the right tools: state-of-the-art advanced microscopy, quantitative data analysis and soft matter and liquid crystal physics theory frameworks," she says. "At this point we don't know what therapies might look like or how they might be administered, but we believe understanding the basic principles will help us advance knowledge and lead to better fertility treatments and healthier pregnancies."

Márquez studied and conducted research in physics for much of her academic career, then shifted her focus and earned advanced biophysics degrees. "When I switched to biophysics, I started seeing the world with a new pair of eyes. What drove me to biophysics is that the work is directly related to health solutions for people and is relevant for human health."

Provided by Syracuse University