Oscillations in metabolite levels and metabolic pathways

We employ metabolomics approaches to identify oscillations in metabolite levels and metabolic pathways. A current study in our lab quantified hundreds of lipids in mouse liver throughout the day and addressed their circadian clock and feeding time dependency. Another project examines the circadian accumulation of polyamines, essential positively charged amines and their involvement in circadian rhythmicity.

Circadian energy homeostasis - from organelles to living animals

We are interested in studying key metabolic outputs from isolated organelles through cultured cells to living animals. An ongoing study in the lab examines the oxygen consumption rate and mitochondrial respiration at high temporal resolution, using the seahorse bio analyzer (for isolated mitochondria and cells), and metabolic cages (for mice).

The molecular architecture of the core clock circuitry

The prevailing paradigm proposes that the core clock molecular circuitry functions based on interlocked negative transcription-translation feedback loops, yet the underlying molecular mechanisms are largely unknown. The discovery that circadian oscillations persist in self- sustained cell autonomous manner in cultured cells provides a relatively facile system for the analysis and identification of the oscillator properties. We employ “state of the art” methods to monitor circadian oscillations in living cells for several successive days using arsenal of circadian reporters. These reporters consist of a circadian promoter that drives the expression of luciferase or florescent protein. Using these assays we can test the involvement of any protein/metabolite of interest in the clock’s function.

Identify novel metabolic sensors

Circadian clocks oscillate in self-sustained and cell autonomous manner, at the same time they readily respond to external timing cue. We are interested in identifying novel core clock components that share a dual function, namely on the one hand generate circadian oscillations and on the other hand respond to external timing cue (e.g. feeding, temperature) as such they serve as metabolic sensors. To this aim, we employ biochemical approaches (e.g. affinity purification columns) to identify metabolites binding protein. An ongoing project in the lab identifies novel nuclear NAD+/NADH binding proteins.