Regulation of molecular clock oscillations and phagocytic activity via muscarinic Ca2+ signaling in human retinal pigment epithelial cells
| Autor: | Masayuki Ikeda, Honami Akechi, Takashi Sugiyama, Alsawaf Ahmad, Kouhei Takeuchi, Masaaki Ikeda, Eri Morioka, Rina Ikarashi, Takashi Ebisawa, Yuzuki Kanda |
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| Rok vydání: | 2017 |
| Předmět: |
0301 basic medicine
Circadian clock Disc shedding Retinal Pigment Epithelium Biology Muscarinic agonist Article 03 medical and health sciences chemistry.chemical_compound 0302 clinical medicine Phagocytosis Biological Clocks Humans Calcium Signaling Circadian rhythm Cell Line Transformed Phase response curve Receptor Muscarinic M3 Multidisciplinary Forskolin Muscarinic acetylcholine receptor M3 Cell biology 030104 developmental biology Gene Expression Regulation chemistry Calcium 030217 neurology & neurosurgery Intracellular |
| Zdroj: | Scientific Reports |
| ISSN: | 2045-2322 |
| DOI: | 10.1038/srep44175 |
| Popis: | Vertebrate eyes are known to contain circadian clocks, however, the intracellular mechanisms regulating the retinal clockwork remain largely unknown. To address this, we generated a cell line (hRPE-YC) from human retinal pigmental epithelium, which stably co-expressed reporters for molecular clock oscillations (Bmal1-luciferase) and intracellular Ca2+ concentrations (YC3.6). The hRPE-YC cells demonstrated circadian rhythms in Bmal1 transcription. Also, these cells represented circadian rhythms in Ca2+-spiking frequencies, which were canceled by dominant-negative Bmal1 transfections. The muscarinic agonist carbachol, but not photic stimulation, phase-shifted Bmal1 transcriptional rhythms with a type-1 phase response curve. This is consistent with significant M3 muscarinic receptor expression and little photo-sensor (Cry2 and Opn4) expression in these cells. Moreover, forskolin phase-shifted Bmal1 transcriptional rhythm with a type-0 phase response curve, in accordance with long-lasting CREB phosphorylation levels after forskolin exposure. Interestingly, the hRPE-YC cells demonstrated apparent circadian rhythms in phagocytic activities, which were abolished by carbachol or dominant-negative Bmal1 transfection. Because phagocytosis in RPE cells determines photoreceptor disc shedding, molecular clock oscillations and cytosolic Ca2+ signaling may be the driving forces for disc-shedding rhythms known in various vertebrates. In conclusion, the present study provides a cellular model to understand molecular and intracellular signaling mechanisms underlying human retinal circadian clocks. |
| Databáze: | OpenAIRE |
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