Coleen Murphy picture small

Dr. Coleen Murphy.  Image courtesy of Dr. Murphy.

Dr. Coleen Murphy is a Professor of Molecular Biology and Genomics at Princeton University. She received her undergraduate degree in Biochemical & Biophysical Sciences from the University of Houston. She then completed her doctoral research in Biochemistry at Stanford. Dr. Murphy did her postdoctoral research in Dr. Cynthia Kenyon’s lab at UCSF, where she solidified her scientific focus: studying the aging process using C. elegans, including genome-wide identification of insulin signaling/FOXO transcriptional targets. Dr. Murphy has received several prestigious awards for her research, including the NIH Pioneer Award, McKnight Endowment Fund for Neuroscience Scholar Award, Keck Scholar, Sloan Fellow, March of Dimes Basil O’ Connor and the American Society of Cell Biology Women in Cell Biology Committee Junior Career Award. Her work on the links between worm and human fertility was previously featured in a NY Times article.

Dr. Murphy’s lab is focused on a few main areas of research that all focus on quality of life with age, using C. elegans to model human aging. 1) How is reproductive span regulated, and how does that relate to the regulation of longevity? 2) How can cognitive decline be slowed? 3) How does the insulin/IGF-1 Signaling/FOXO pathway and its interactions regulate longevity, reproductive span, and cognitive decline? Dr. Murphy’s seminar focused on reproductive span and how this relates to lifespan. The control of somatic aging is intimately connected with the ability to reproduce; as an example, slowed germline proliferation in response to low nutrients extends lifespan, allowing for late mating and reproduction at a time when resources are more plentiful, increasing the probability of reproductive success. A third component links reproduction and longevity, the actual effects that mating has on the mother.  They found that males hijack the well-studied “longevity pathways,” altering the mothers’ gene expression and metabolism toward a rapidly aging profile, possibly to prevent other males from mating with that female, thus ensuring that the offspring are theirs. Behavior is also affected by mating, in both males and females.

C. elegans

Image of a C. elegan. Image credit Wikipedia.

SAGE sat down with Dr.Murphy to ask a few more questions…

Q: There is a Germ-soma Conflict Theory of Aging: that the death of the soma (body) is identified as the ultimate cost of reproduction. Do you support this idea?

CM: No. I think people focused on progeny number for a long time, but I think the timing of reproduction and when mating occurs is more important. There are studies which show that women who are able to give birth without artificial reproductive technologies (ART) later in life may live longer. There are genetic mutations, such as reduced insulin signaling, that extend lifespan that also extend the age at which an animal can still have progeny. Dr. Cynthia Kenyon had an excellent Science paper where they put worms on daf-2 RNAi (a piece of RNA that causes mRNA degradation) at difference time points. They were actually able to uncouple lifespan from progeny production. When worms were put on daf-2 RNAi on day-1 of adulthood, they lived long but did not reduce progeny number. So I don’t think there is a tradeoff between soma and reproduction in individuals, which argues against theories that state that energy has to be put into either the soma or germline—it instead suggests that signaling controls these decisions in the animal.

Q: What methods do you employ to extend your own lifespan and healthspan?

CM: Not much! But I try to stay in good shape. There is a large body of research which shows that insulin signaling regulation is very important for both lifespan and healthspan. Since I enjoy eating, I am not going to practice a regimen of rigorous calorie restriction. However, it seems logical to eat in moderation and to stay in good shape.

Q: What is the ultimate goal of your research?

CM: I think the entire aging field is doing a respectable job of finding ways to help people live healthier and longer lives, and our work on cognitive aging will help with that as well. I also work in a slightly different area, focusing on reproductive aging. I envision my research eventually helping inform women about how long their reproductive span is, that is until which age they can give birth. This research could potentially decrease the rates of age-related birth defects. This area is important because even if we can push our lifespan to 120 years, women would still be facing the same reproductive challenges. Being able to have healthy children is an important issue. As a researcher I am fortunate that worms are such an excellent model in which to study reproductive span in relation to healthspan and lifespan.