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The relationship between mitochondria function and circadian clock in peripheral oscillators

100%

Kazmierczak A., Schmitt K., Grimm A., Strosznajder J. B., Eckert A.

Acta Neurobiologiae Experimentalis

2013

tom 73

nr 1

Circadian rhythms govern a wide variety of physical, behavioral and metabolic changes that follow a roughly 24-hour cycle, responding primarily to light and darkness in an organism’s environment. These are controlled by the circadian clock mechanism, where rhythm-generating mechanism is encoded by a transcription-translation feedback loop. Numerous studies have pointed to a cyclic relationship wherein the rhythm impacts metabolic activity and metabolism feeds back to impinge upon the rhythm. Mitochondria play a pivotal role in regulating cellular energy and were shown to be strategically positioned at the intersection between circadian rhythm and cell metabolism. Nevertheless little is known about their function in controlling the circadian rhythm. In our study, we investigated the involvement of circadian clock in mitochondrial function as well as mitochondria-dependent regulation of circadian clock. The study was carried out in primary human fibroblasts, an already established model to investigate molecular clock mechanisms in vitro. We have found that mitochondria activity as well as network activities showed rhythmic changes within 24 hours. Circadian pattern was detected for mitochondrial ROS including superoxide anion production. A significant 24-hour oscillation was found for cellular redox state. Furthermore, mitochondrial ATP levels were rhythmic and the maximum of ATP production paralleled the peak of mitochondrial ROS level and the mitochondrial network formation. Circadian rhythm was also detected for calcium ions concentration. Increase of ATP synthesis as well as changes in calcium and ROS level activated AMP-dependent protein kinase (AMPK). We have found that in primary human fibroblasts AMPK protein level and activity fluctuate in an antiphase relationship with rhythmic ATP production. Summarizing, our data provide the evidence for circadian regulation of mitochondrial dynamics and suggest that changes of mitochondrial activity may directly influence cellular clock. Supported by grants from Sciex 10. 258 to A.K. as well as Swiss National foundation (SNF No 310030_122572) and Synapsis Foundation to A.E

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24-hour cycle of variability in contents of nitrogen forms in the surface microlayer of the Baltic Sea lagoon lake (North Poland) - Part I

80%

Antonowicz J., Trojanowski J., Trojanowska C.

Baltic Coastal Zone. Journal of Ecology and Protection of the Coastline

2010

tom 14

In July 2000 the diurnal cycle of analyses was conducted in order to determine variation in the concentrations of nitrogen and calcium compounds as well as dissolved gases in surface microlayers of a shallow coastal barrier lake located at the Baltic Sea coast. Water for analyses was collected in a diurnal cycle for the period of 24 h from lake Dołgie Wielkie. The analyses were conducted on the surface microlayer with a thickness of approx. 100 μm, a layer with a thickness of approx. 250 6m and a layer of subsurface water from a depth of 15 cm. Based on the analyzed data, information was collected on the migration of nitrogen compounds between the analyzed layers. Changes were observed in nitrogen forms reduced to oxidized forms and vice versa.

Ograniczanie wyników

1 Acta Neurobiologiae Experimentalis

1 Baltic Coastal Zone. Journal of Ecology and Protection of the Coastline

1 Antonowicz J.

1 Eckert A.

1 Grimm A.

1 Kazmierczak A.

1 Schmitt K.

1 Strosznajder J. B.

1 Trojanowska C.

1 Trojanowski J.

1 2013

1 2010

Wyniki wyszukiwania

The relationship between mitochondria function and circadian clock in peripheral oscillators

24-hour cycle of variability in contents of nitrogen forms in the surface microlayer of the Baltic Sea lagoon lake (North Poland) - Part I