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Satchidananda Panda

 

Satchidananda Panda

Satchidananda Panda

Assistant Professor
Regulatory Biology Laboratory

"Going to bed at night and waking up in the morning is a seemingly simple routine we follow in every season. I want to understand how our brain clock keeps track of time in all seasons and time zones and tells our body when to sleep, when to wake up, and when to eat."

Unlike the millions of rod and cone cells imparting vision, melanopsin—a photopigment that measures the intensity of incoming light—is only present in roughly 2,000 cells, which are knows as melanopsin-expressing retinal ganglion cells, or mRGCs. Embedded in the inner retina, these spidery cells send signals directly to the human circadian clock, which synchronizes the body's daily rhythms with the rising and the setting of the sun. It tells the body when it is time to go to sleep, when to be hungry, and when to wake up and makes us feel completely out of sync when we cross several time zones.

It had been known that blind mice without functional rods and cones can still use mRGCs to adjust their biological clock and that mice without melanopsin could still adjust their circadian rhythms as well. Since mice developing without melanopsin might compensate during their development for the lack of incoming information about light intensity, resulting in muddled results, Panda and his team devised a system that allowed them to specifically and efficiently shut down all melanopsin-expressing cells while leaving the retina intact. Eliminating mRGCs—and not just melanopsin— made the circadian clock completely blind to light but left normal vision intact.

What they found was that the mammalian time-keeping system relies on information from melanopsin—and to a lesser extent from rods and cones—to collect information about light intensity. Their experiments pinpointed mRGCs as the location where all the incoming information about the brightness of ambient light is integrated and forwarded to the circadian clock.

Understanding how mRGCs do their job may one day allow scientists to reset the body's biological clock with a pill to alleviate symptoms associated with jet lag, shifts in work schedules, seasonal changes in day lengths, and disorders such as insomnia and depression. Panda has already started screening small molecules for their ability to tweak melanopsin's light-sensing properties and thereby slow down or enhance the resetting of our biological clock.

Lab Photo

Left to right
Front row: Megumi Hatori, Victoria Piamonte, Satchin Panda, Sheena Keding, Hiep Le Back row: Christopher Vollmers, Luciano DiTacchio, Shubhroz Gill, Greg Fleishman

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Satchidananda Panda

Faculty

Satchidananda Panda

Satchidananda Panda

Assistant Professor
Regulatory Biology Laboratory

Satchin Panda, an assistant professor in the Regulatory Biology Laboratory, is interested in understanding the molecular mechanism of the biological clock in a mouse model system. The biological clock or circadian oscillator in most organisms coordinates behavior and physiology with the natural light-dark cycle. His laboratory uses genetic, genomics and biochemical approaches to identify genes under circadian regulation in different organs and to understand the mechanism of such regulation. His lab also tries to characterize the mechanism by which the circadian oscillator is synchronized to the natural light-dark condition. Both classical rod/cone photoreceptors and a newly identified ocular photopigment melanopsin participate in photoentrainment of the clock. Research in his lab is geared towards identifying molecular components and events critical for transmitting light information from the eye to the master oscillator in the brain.

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