Aron A. Moscona, PhD, 1921-2009

January 26, 2009

A renowned developmental biologist who was one of the first to show how cells recognize each other and interact, Aron A. Moscona, PhD, the Louis Block Professor Emeritus of molecular genetics and cell biology and of pathology at the University of Chicago and a member of the U.S. National Academy of Science, died from heart failure January 14 in Manhattan. He was 87.

Moscona was best known for a series of experiments that revealed how cells arrange themselves to form tissues or organs in the body. He developed techniques to separate cells at early stages of development, suspend them in fluid and allow them to grow back together. He showed that the individual cells from an organ can find each other and reassemble properly, "like parts," he said, "of an animated jigsaw puzzle," and that specific molecules on cell surfaces govern these interactions during development.

Moscona's work, beginning at Strangeways Research Laboratory in Cambridge, England, in 1952, and continuing at the University of Chicago from 1958 to 1992, influenced a generation of scientists. Many of today's leading developmental biologists were stimulated to pursue scientific careers after hearing him speak about cells and organ development. "He was working in that specialty before the tools of that field had even been developed," said Linda Degenstein, a technician who worked in Moscona's laboratory for decades.

"Aron Moscona's efforts were extraordinarily imaginative, wide ranging in scope and truly of seminal significance for the field of developmental biology," said Donald Steiner, MD, the A.N. Pritzker Professor of Biochemistry and Molecular Biology and a member of the Howard Hughes Medical Institute at the University of Chicago.

"Moscona did fundamental work that was way ahead of his time, with significance extending basic biology into areas such as cancer metastasis," said colleague Ralph Weichselbaum, MD, the Ludwig Professor and chairman of radiation and cellular oncology at the University of Chicago. "He was also a decent guy. Some found him a bit brusque, but he extended a lot of guidance and support to me when I first came to the University."

"Aron's pioneering research in tissue and organ development set the foundations for decades of subsequent molecular studies in this field, and also provided enduring insights into cancer progression," said Elaine Fuchs, PhD, a former colleague of Moscona at the University of Chicago and now the Rebecca C. Lancefield Professor and Howard Hughes Investigator at the Rockefeller University. "Aron was a wonderful mentor to his students and to younger colleagues like me. He taught by example. He set rigorous standards for scientific excellence and expected us to meet them with the passion he expressed throughout his career."

Aron Arthur Moscona was born July 4, 1921, in Haifa, Israel. He graduated from the Reali High School in Haifa then attended Hebrew University, in Jerusalem, where he earned his PhD in endocrinology-biochemistry in 1950. He spent two years as a post-doctoral fellow at the Strangeways Research Laboratory at Cambridge, before joining the faculty at the University of Jerusalem as an associate professor of physiology in 1953. He then spent two years as an investigator at Rockefeller University in New York City, before joining the faculty at the University of Chicago as an associate professor of zoology in 1958.

He rose quickly through the ranks at the University, becoming a professor in 1960. He co-founded the committee on developmental biology in 1969 and was named the Louis Block Professor of Biology in 1974.

A prolific author, he published 261 scientific papers, was co-author of the text book Introductory Concepts in Developmental Biology, and served as founder and coeditor of the journal Current Topics in Developmental Biology. He served as president of the International Society of Developmental Biology from 1976 to 1980 and as a member of several national advisory panels, including the President's Biomedical Research Panel in 1975. He was the chair of the board of scientific counselors of the National Institute of Child Health and Human Development from 1982-1986, served on an NIH advisory panel on human fetal tissue transplantation in 1988, and joined the board of governors of Tel Aviv University in 1984, where he served until his recent illness.

Moscona won multiple honors for his research, including membership in the National Academy of Sciences in 1977 and in the American Academy of Arts and Sciences in 1987, as well as its Italian counterpart, the Accademia di Science e Lettere. He received many awards, including the Claude Bernard Medal in Experimental Medicine from the European Association for the Study of Diabetes, Japan's Azabu Gold Medal and the Alcon Prize in Visual Sciences.

As a post-doctoral fellow at Cambridge, Moscona directed his attention to questions related to the emerging field of developmental biology, especially how different cell types arose from a fertilized egg cell and organized themselves into tissues and organs. He developed novel techniques to answer some of those questions. Using the digestive enzyme trypsin, he dissolved tissues into individual cells that he kept alive in a flask of culture media, where they could "recognize their own kind," as he put it, "sort out and reassemble into tissue-like patterns."

He constantly revised the approach to study related topics in different tissue types--including muscle, skin, liver, pancreas, retina and brain--and to apply them to different life forms, ranging from marine sponges to chickens, snakes, mice and even human tissues.

One of his central findings was that specific cell-surface molecules defined each cell type, serving as microscopic flags to identify each cell as a liver, kidney or brain cell. These markers, which Moscona labeled "cognins," (later known as cadherins) enabled the dissociated cells to recognize and connect with similar cells. He also showed how forming these cell-to-cell connections could alter gene expression and that they were necessary for the embryonic cells to mature.

In the mid-1960s, much of his efforts focused on the mechanisms that controlled nerve cell differentiation. One spin-off from this was the development in 1972 by Moscona and colleague Beatrice Garber of aggregate neural tissues that could survive for years, proving a new tool for study of the brain. Neuroscientists at the University, for example, used these neural aggregates, known as "mini-brains," to study the neurotoxicity of various drugs of abuse.

Moscona's partner in many of these efforts was his wife, Malka, who had also grown up in Haifa. Although they attended the same high school, they did not meet until later, at the Hebrew University in Jerusalem, and married in 1956. A very popular instructor and winner of the University's Quantrell Award for exemplary teaching, Malka Moscona also joined the Chicago faculty in 1958, becoming an associate professor.

"They worked together collaboratively for 40 years, in the same laboratory, carrying out projects together from 1958 until 1974, and were jointly responsible for the body of science," said their daughter Anne Moscona, MD, a virologist and infectious disease specialist at Weill Medical College of Cornell University in New York City.

Moscona retired in 1992. He and his wife moved to New York, to be near their daughter and her family. His wife continued her science outreach and teaching work there. "Late in life," his daughter Anne said, "he became very nurturing." He took his two grandsons to their classes, picked them up from school, took them to the playground, cooked dinners for them, "bought them books," she added, "and instilled a love of learning, history, music, art and, of course, science."

Moscona is survived by his wife of 53 years and scientific collaborator, Malka, his daughter Anne, and two grandchildren, Jacob and Ari, all of Manhattan.