Monitoring mitochondrial calcium and metabolism in the beating MCU-KO heart

Kosmach, Anna; Román, Bárbara; Sun, Junhui; Femnou, Armel N.; Zhang, Fan; Liu, Chengyu; Combs, Christian A.; Balaban, Robert S.; Murphy, Elizabeth

doi:10.1016/j.celrep.2021.109846

Cited by 23 publications

(10 citation statements)

References 32 publications

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“…We then tested whether free mitochondrial Ca 2+ levels would be altered under basal conditions in cells lacking Sirt3. For this, we used the mitochondrial Ca 2+ indicator dye Rhodamine-2 ( Kosmach et al, 2021 ). These results revealed that free mitochondrial Ca 2+ levels were significantly increased in Sirt3-KO MEFs, as indicated by the increased staining intensity of Rhodamine-2 ( Figure 1C ).…”

Section: Resultsmentioning

confidence: 99%

“…Under these basal conditions, no differences in mitochondrial membrane potential were observed between Rhodamine-123 stained Sirt3-KO and WT MEFs using flow cytometry analysis ( Figure 1D ). The lack of difference in ΔΨm is an important validation, as the mitochondrial accumulation of the Ca 2+ indicator dye Rhodamine-2 is influenced by mitochondrial membrane potential ( Kosmach et al, 2021 ). Thus, the increase in Rhodamine-2 signal observed in the Sirt3-KO MEFS reflects increased free mitochondrial Ca 2+ levels, and not a difference in dye loading efficiency.…”

Section: Resultsmentioning

confidence: 99%

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Mitochondrial brain proteome acetylation levels and behavioural responsiveness to amphetamine are altered in mice lacking Sirt3

et al. 2022

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Post-translational modification of mitochondrial proteins represents one mechanism by which the functional activity of mitochondria can be regulated. In the brain, these modifications can influence the functional properties of different neural circuitries. Given that the sirtuin family member Sirt3 represents the primary protein deacetylase enzyme in mitochondria, we tested whether brain mitochondrial proteome acetylation would increase in male or female mice lacking Sirt3. Our results confirm that whole brain mitochondrial proteome acetylation levels are indeed elevated in both sexes of Sirt3-KO mice relative to controls. Consistently, we found the mitochondria of mouse embryonic fibroblast (MEF) cells derived from Sirt3-KO mice were smaller in size, and fewer in number than in wild-type MEFs, and that mitochondrial free calcium levels were elevated within the mitochondria of these cells. As protein acetylation can influence mitochondrial function, and changes in mitochondrial function have been linked to alterations in neural circuit function regulating motor activity and anxiety-like behavior, we tested whether Sirt3-deficient mice would display sensitized responsiveness to the stimulant amphetamine. Both male and female Sirt3-KO mice displayed hyper-locomotion and attenuated anxiety-like behavior in response to a dose of amphetamine that was insufficient to promote any behavioural responses in wild-type mice. Collectively, these results confirm that Sirt3 regulates mitochondrial proteome acetylation levels in brain tissue, and that the absence of Sirt3 increases the sensitivity of neural systems to amphetamine-induced behavioural responses.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Mitochondrial brain proteome acetylation levels and behavioural responsiveness to amphetamine are altered in mice lacking Sirt3

et al. 2022

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“…To test whether intrasarcomere CSA heterogeneity is simply an artifact of the fixation and sample processing required to collect the FIB-SEM datasets described above, we performed stimulated emission depletion (STED) super-resolution microscopy on live mouse flexor digitorum brevis (FDB) muscles labeled with fluorophores for mitochondria (genetically encoded TOMM20-mNeon 45 ) and F-actin (SPY555-FastAct) (Fig. 1l-n).…”

Section: Sarcomere Cross-sectional Area Varies Along Its Lengthmentioning

confidence: 99%

Mitochondrial network configuration influences sarcomere and myosin filament structure in striated muscles

et al. 2022

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Sustained muscle contraction occurs through interactions between actin and myosin filaments within sarcomeres and requires a constant supply of adenosine triphosphate (ATP) from nearby mitochondria. However, it remains unclear how different physical configurations between sarcomeres and mitochondria alter the energetic support for contractile function. Here, we show that sarcomere cross-sectional area (CSA) varies along its length in a cell type-dependent manner where the reduction in Z-disk CSA relative to the sarcomere center is closely coordinated with mitochondrial network configuration in flies, mice, and humans. Further, we find myosin filaments near the sarcomere periphery are curved relative to interior filaments with greater curvature for filaments near mitochondria compared to sarcoplasmic reticulum. Finally, we demonstrate variable myosin filament lattice spacing between filament ends and filament centers in a cell type-dependent manner. These data suggest both sarcomere structure and myofilament interactions are influenced by the location and orientation of mitochondria within muscle cells.

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“…The discrepancies in experimental findings obtained from isolated mitochondria, isolated cardiomyocytes, and whole hearts are other issues that remain to be solved. Recent advances in imaging techniques used to evaluate electrophysiological and metabolic properties of single cells and even organelles in tissue are promising [ 65 , 85 ]. By utilizing these techniques, it is expected that our understandings of the roles of NCX mit in healthy as well as in failing hearts will be further deepened.…”

Section: Future Perspectivesmentioning

confidence: 99%

Physiological and Pathophysiological Roles of Mitochondrial Na+-Ca2+ Exchanger, NCLX, in Hearts

Takeuchi

Matsuoka

2021

Biomolecules

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It has been over 10 years since SLC24A6/SLC8B1, coding the Na+/Ca2+/Li+ exchanger (NCLX), was identified as the gene responsible for mitochondrial Na+-Ca2+ exchange, a major Ca2+ efflux system in cardiac mitochondria. This molecular identification enabled us to determine structure–function relationships, as well as physiological/pathophysiological contributions, and our understandings have dramatically increased. In this review, we provide an overview of the recent achievements in relation to NCLX, focusing especially on its heart-specific characteristics, biophysical properties, and spatial distribution in cardiomyocytes, as well as in cardiac mitochondria. In addition, we discuss the roles of NCLX in cardiac functions under physiological and pathophysiological conditions—the generation of rhythmicity, the energy metabolism, the production of reactive oxygen species, and the opening of mitochondrial permeability transition pores.

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Monitoring mitochondrial calcium and metabolism in the beating MCU-KO heart

Cited by 23 publications

References 32 publications

Mitochondrial brain proteome acetylation levels and behavioural responsiveness to amphetamine are altered in mice lacking Sirt3

Mitochondrial brain proteome acetylation levels and behavioural responsiveness to amphetamine are altered in mice lacking Sirt3

Mitochondrial network configuration influences sarcomere and myosin filament structure in striated muscles

Physiological and Pathophysiological Roles of Mitochondrial Na+-Ca2+ Exchanger, NCLX, in Hearts

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