Diversity of mitochondrial Ca2+ signaling in rat neonatal cardiomyocytes: Evidence from a genetically directed Ca2+ probe, mitycam-E31Q
| Autor: | Martin Morad, Sarah Kettlewell, Godfrey L. Smith, Lars Cleemann, Sarah Haviland |
|---|---|
| Rok vydání: | 2014 |
| Předmět: |
Fura-2
Calmodulin Physiology Population chemistry.chemical_element Mitochondrion Calcium Biology Article Fluorescence Mitochondria Heart Rats Sprague-Dawley chemistry.chemical_compound Cytosol Animals Humans Myocytes Cardiac Calcium Signaling education Molecular Biology Cells Cultured Calcium signaling education.field_of_study Cell Biology Anatomy Rats Cell biology HEK293 Cells Animals Newborn chemistry Molecular Probes biology.protein Signal transduction Signal Transduction |
| Zdroj: | Cell Calcium. 56:133-146 |
| ISSN: | 0143-4160 |
| Popis: | I(Ca)-gated Ca(2+) release (CICR) from the cardiac SR is the main mechanism mediating the rise of cytosolic Ca(2+), but the extent to which mitochondria contribute to the overall Ca(2+) signaling remains controversial. To examine the possible role of mitochondria in Ca(2+) signaling, we developed a low affinity mitochondrial Ca(2+) probe, mitycam-E31Q (300-500 MOI, 48-72h) and used it in conjunction with Fura-2AM to obtain simultaneous TIRF images of mitochondrial and cytosolic Ca(2+) in cultured neonatal rat cardiomyocytes. Mitycam-E31Q staining of adult feline cardiomyocytes showed the typical mitochondrial longitudinal fluorescent bandings similar to that of TMRE staining, while neonatal rat cardiomyocytes had a disorganized tubular or punctuate appearance. Caffeine puffs produced rapid increases in cytosolic Ca(2+) while simultaneously measured global mitycam-E31Q signals decreased more slowly (increased mitochondrial Ca(2+)) before decaying to baseline levels. Similar, but oscillating mitycam-E31Q signals were seen in spontaneously pacing cells. Withdrawal of Na(+) increased global cytosolic and mitochondrial Ca(2+) signals in one population of mitochondria, but unexpectedly decreased it (release of Ca(2+)) in another mitochondrial population. Such mitochondrial Ca(2+) release signals were seen not only during long lasting Na(+) withdrawal, but also when Ca(2+) loaded cells were exposed to caffeine-puffs, and during spontaneous rhythmic beating. Thus, mitochondrial Ca(2+) transients appear to activate with a delay following the cytosolic rise of Ca(2+) and show diversity in subpopulations of mitochondria that could contribute to the plasticity of mitochondrial Ca(2+) signaling. |
| Databáze: | OpenAIRE |
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