Seminar "Choroid Plexus Circadian Clock: Mechanism of Synchronization and Feedback to the SCN" by Dr. Jihwan Myung

Speaker:

Dr. Jihwan Myung Taipei Medical University

Title:  

Choroid Plexus Circadian Clock: Mechanism of Synchronization and Feedback to the SCN

Abstract:

The circadian clocks in mammals have a hierarchical organization, governed by the suprachiasmatic nucleus (SCN) in the hypothalamus. The brain itself contains multiple loci that maintain autonomous circadian rhythmicity. However, the importance of other brain clocks in this hierarchy remains unclear. We examine circadian oscillations of clock gene expression in various brain loci and discover robust, high-amplitude, and relatively faster oscillations than the SCN in the choroid plexus (CP). Our computational analysis and modeling show that the CP achieves these properties by synchronization of ‘twist’ circadian oscillators via gap junctional connections. The CP clock tunes the SCN clock probably through circulation of cerebrospinal fluid and finely adjusts the behavioral circadian rhythm. We demonstrate this by in vitro co-culture and by in vivo silencing of the CP circadian clock through targeted deletion of Bmal1.

Reference:

            J. Myung, S. Hong, D. DeWoskin, E De Schutter, D.B. Forger and T. Takumi: GABA-mediated repulsive coupling between circadian clock neurons in the SCN encodes seasonal time. Proceedings of the National Academy of Sciences USA 112: E3920-3929.