Nutrition Science PhD studies led to career in genetic disease therapy for HHS Distinguished Alumna

S. Sianna CastilloPhoto provided

Written by: Tim Brouk, tbrouk@purdue.edu

A chance to study nutrition at the molecular level lured S. Sianna Castillo to Purdue University’s College of Health and Human Sciences (HHS). She represents the Department of Nutrition Science as its 2022 Distinguished Alumni Award winner.

In the mid 1990s, it wasn’t common for universities to have nutrition science programs breaking things down to the molecular level within vitamins and other minerals and organic compounds.

“One of the tracks you could take at Purdue was biochemical and molecular nutrition,” said Castillo, currently the senior director at Sangamo Therapeutics in Richmond, California. “I wanted to get more into how nutrients regulate genes.”

Castillo studied under Purdue nutrition science Professor Dorothy Teegarden, whose work explores the metabolism of vitamin D. Influenced by Teegarden’s research on signaling pathways regulated by vitamin D, Castillo’s research area focused on signaling pathways regulated by sphingolipid metabolism and how they trigger cell genes on and off in cancer prevention.

Her success at Purdue led Castillo to a postdoctoral position at the National Institutes of Health. There, she learned more about molecular biology. Her career goal of working in academia was replaced with a career aspiration in industry, which she has found for the past 20 years, first at BioMarin Pharmaceutical — where she climbed the ladder from scientist to a director of regulatory affairs. A highlight of Castillo’s career at BioMarin was helping get a therapeutic drug approved in the U.S. and European Union for people with phenylketonuria, a rare genetic disease with nutritional consequences that Castillo learned about while at Purdue.

At Sangamo, Castillo continues her work with rare genetic diseases by helping develop genomic medicines based on research of how diseases can be better understood, fought, and potentially cured by working with a patient’s DNA. A recent example is the development of zinc finger technology, which can be used to create genomic medicines for genome engineering inside the body or for cell therapy outside of the body. For example, in cell therapy, cells are removed from a patient and then engineered with the zinc finger technology to fix the genetic issue before being delivered back to the patient.

“We’re trying to understand what the underlying genetic cause of disease states and from the therapeutic realm, how can you treat that?” Castillo explained.

Castillo credits her time at Purdue for igniting her love for molecular science and continuing her passion for research. Recent work has included an old friend from Purdue — sphingolipids. The new work examines Fabry disease, a rare genetic disease that increases risks of heart attacks, strokes and kidney failure due to the patient’s lack of enzymes that break down fats.

“I can go back and remember when I was at Purdue, and this is one of those diseases they talked about,” Castillo said. “Flash forward 20-some years later, and I’m working on a therapy for it.

“You get exposed to so much when you’re in grad school, all that foundation and information that I was exposed to has helped me years and years later. That is pretty remarkable.”