Dataset Information

MICU3 Plays an Important Role in Cardiovascular Function

ABSTRACT: Mitochondrial calcium regulates bioenergetics but also serves as a trigger for cell death.1 With a sustained increase in catecholamine or a large increase in cytosolic calcium as occurs with ischemia, mitochondrial calcium can rise to high levels, leading to activation of the mitochondrial permeability transition pore, thus initiating cell death.1 Calcium uptake into mitochondria occurs via the MCU (mitochondrial calcium uniporter), which is regulated by 3 EF (EF hand protein) hand proteins, MICU (mitochondrial calcium uptake) 1, 2, and 3.2 MICU1/MCU ratios vary in different tissues,3 and alterations in substrate flux have been shown to regulate MICU1 levels altering MCU-mediated calcium uptake.4 MICU3 has generally been thought to function primarily in neuronal tissue where it is highly expressed and thus has been largely ignored in other tissues such as the heart. We performed quantitative proteomics using Tandem mass tag labeling coupled to liquid chromatography and tandem mass spectrometry to analyze MCU and MCU regulators in cardiac and hepatic mitochondria (Figure [A]). Normalizing MICU levels to MCU in heart and liver mitochondria, we found that the MICU1/MCU ratio was 0.75 in liver and 0.25 in heart, which is consistent with previous studies3; however, the MICU3/MCU ratio in heart is >3-fold higher than that found in liver. To confirm that the MICU3 we observed in heart mitochondria was not due to contamination by mitochondria from nerve tissue in heart, we isolated cardiomyocytes and compared the ratio of MICU3 to MCU in cardiomyocytes and heart mitochondria and found similar ratios (Figure [B]). These data suggest that MICU3 might play a role in regulating MCU in heart.

INSTRUMENT(S): Orbitrap Fusion Lumos

ORGANISM(S): Mus Musculus (ncbitaxon:10090)

SUBMITTER: Elizabeth Murphy, PhD

PROVIDER: MSV000088439 | MassIVE | Tue Nov 23 20:13:00 GMT 2021

SECONDARY ACCESSION(S): PXD029890

REPOSITORIES: MassIVE

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MICU3 Plays an Important Role in Cardiovascular Function.

Puente Bao N BN Sun Junhui J Parks Randi J RJ Fergusson Maria M MM Liu Chengyu C Springer Danielle A DA Aponte Angel M AM Liu Julia C JC Murphy Elizabeth E

Circulation research 20201016 12

PMID: 33059536

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Project description:Calcium signaling is a central regulator of cardiomyocyte growth and function. Calmodulin is a critical mediator of calcium signals. Because the amount of calmodulin within cardiomyocytes is limiting, precise regulation of calmodulin expression may be an important for regulation of calcium signaling. In this study, we show for the first time that calmodulin levels are regulated post-transcriptionally in heart failure. The cardiomyocyte-restricted microRNA miR-1 inhibited translation of calmodulin-encoding mRNAs via highly conserved target sites within their 3â-untranslated regions. In keeping with its effect on calmodulin expression, miR-1 downregulated calcium-calmodulin signaling through the calcineurin to NFAT. miR-1 also negatively regulated expression of Mef2a and Gata4, key transcription factors that mediate calcium-dependent changes in gene expression. Consistent with downregulation of these hypertrophy-associated genes, miR-1 attenuated cardiomyocyte hypertrophy in cultured neonatal rat cardiomyocytes and in the intact adult heart. Our data indicate that miR-1 regulates cardiomyocyte growth responses by negatively regulating the calcium-signaling components calmodulin, Mef2a, and Gata4. We show that miR-1 is downregulated in a murine heart failure model. miRNAs expression changes were measured in calcineurin transgenic model of heart failure and control mice using a Luminex platform. Reduced miR-1 expression was associated with broad alteration in expression of predicted target genes. To test this, we measured miRs including miR-1 and genome wide transcriptome changes in vivo and in vitro system. Calcineurin transgenic heart was compared to nontransgenic heart (NTg vs. CNTg). We also investigated the gene expression changes during the course of cardiomyocytes differentiation using DMSO treated P19CL6 cell lines. Two time points (day 6 and day 10) were compared to identified the gene expression changes of predicted miR-1 targets (Day 6 vs. Day 10).

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Dataset Information

MICU3 Plays an Important Role in Cardiovascular Function

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MICU3 Plays an Important Role in Cardiovascular Function.

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