Vanessa Leone, PhDPost-Doctoral Scholar
My investigations have focused on understanding the interaction between gut microbes and the host (us) under conditions of both health and disease. I made the novel discovery that our gut microbes vary over the course of the day, such that our daytime gut microbes are dramatically different than our nighttime gut microbes. This daily variation in gut microbes serves as a key regulator of our own biological clock, which is known as circadian rhythm. Circadian (meaning approximately – circa; one day – diem) drives the body’s internal 24-hour clock responding to light-dark (i.e., day/night) cues that coordinate our sleep-wake patterns as well as our eating behavior and metabolism. Thus, circadian rhythm determines the metabolic set point of an individual. Differences in this metabolic set point across individuals in part may explain why some people remain lean despite overeating while others remain obese despite dieting. My work clearly shows that what the gut microbes are doing during the day (a time of energy acquisition and burning) is very different from what they are doing during the night (a time of energy storage). This difference in the timed metabolic activity of gut microbes leads to a change in the active metabolites that they produce, directly impacting our own circadian biology. Disrupting these cycles by eating Western-style diets or by shifting sleeping habits (i.e., shift work, sleep apnea, or jet lag) can lead to metabolic imbalances that promote the development of obesity.