Jennifer Hurley, Rensselaer Polytechnic Institute – Circadian Clock Disruption

How important is it to be in tune with your circadian clock?

Jennifer Hurley, assistant professor of biological sciences at Rensselaer Polytechnic Institute, delves into this question.

Dr. Jennifer Hurley received her B.S. from Juniata College in 2004 in Molecular Biology and her Ph.D. at Rutgers/UMDNJ for studying the function of Toxin-Antitoxin modules. She completed her Postdoctoral fellowship at the Geisel School of Medicine at Dartmouth investigating the circadian clock. Dr. Hurley joined the Department of Biological Sciences at Rensselaer Polytechnic Institute in 2015 as an Assistant Professor. Dr. Hurley’s research focus is on the fundamental mechanisms underlying circadian rhythms. Circadian rhythms are an important component in understanding how organisms function within the photoperiodic world that we live in; defects in the circadian clock or disruptions in circadian rhythms are linked to a wide range of sleep, metabolic and psychological disorders in humans. Her lab investigates the relationship between the core clock mechanism and the output that the clock controls using a combination of molecular genetics and biochemical techniques as well as a biostatistical/computational approach using “omic” scale data. Dr. Hurley’s work has been recognized by the Genetics Society of America, the American Society for Biochemistry and Molecular Biology, and the Ruth Kirschstein National Research Service Award.

Circadian Clock Disruption

Most life on Earth is tuned to the planet’s 24-hour cycle by a system we call the circadian clock. This clock creates daily oscillations in many organisms, including humans, and controls a great deal of physiology, for example the sleep/wake cycle. Interfering with the circadian clock is a serious affair; research shows that people who regularly function out of sync with their circadian clocks – like night shift workers – exhibit increased rates of cancer, diabetes, heart disease, and many more ailments.

Circadian clocks are built to receive and interpret information from the environment. However, until recently scientists assumed the clock was buffered against the effects of most constant environmental conditions, reasoning that a clock should tick consistently regardless of its surroundings. However, our recent research challenges that assumption. Our work investigated the circadian clock of a plankton that had adapted to living in water contaminated with dissolved road salt. By tracking the plankton’s clock at the molecular level, using levels of messenger RNA, we found that the circadian clock in these plankton had stopped ticking, even when the dissolved road salt was no longer present. Put plainly, this suggests that the adaptation to tolerate an environmental contaminant can permanently suppress circadian functions long after the contaminant is gone.

The potential implications of this research are substantial. From an environmental perspective, plankton, which are a food source for many fish, may be making a monumental tradeoff in their effort to tolerate environmental contaminants. As plankton participate in a daily migration that may be guided by their circadian clock; the disruption of plankton clocks could affect an entire aquatic ecosystem. From a human health perspective, the circadian clock in humans is similar to that in plankton. Therefore, our research suggests that it is possible that the human clock may also be affected as a result of exposure to environmental contamination, implying that environmental contaminants could have broader human health effects than what is currently recognized.