Limits...
Irisin Controls Growth, Intracellular Ca2+ Signals, and Mitochondrial Thermogenesis in Cardiomyoblasts.

Xie C, Zhang Y, Tran TD, Wang H, Li S, George EV, Zhuang H, Zhang P, Kandel A, Lai Y, Tang D, Reeves WH, Cheng H, Ding Y, Yang LJ - PLoS ONE (2015)

Bottom Line: Remarkably, irisin is highly expressed in myocardium, but its physiological effects in the heart are unknown.In conclusion, irisin in a certain concentration rage increased myocardial cell metabolism, inhibited cell proliferation and promoted cell differentiation.These effects might be mediated through PI3K-AKT and Ca2+ signaling, which are known to activate expression of exercise-related genes such as follistatin and myocardin.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, Immunology, and Laboratory Medicine, University of Florida College of Medicine, Gainesville, FL, 32610, United States of America.

ABSTRACT
Exercise offers short-term and long-term health benefits, including an increased metabolic rate and energy expenditure in myocardium. The newly-discovered exercise-induced myokine, irisin, stimulates conversion of white into brown adipocytes as well as increased mitochondrial biogenesis and energy expenditure. Remarkably, irisin is highly expressed in myocardium, but its physiological effects in the heart are unknown. The objective of this work is to investigate irisin's potential multifaceted effects on cardiomyoblasts and myocardium. For this purpose, H9C2 cells were treated with recombinant irisin produced in yeast cells (r-irisin) and in HEK293 cells (hr-irisin) for examining its effects on cell proliferation by MTT [3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay and on gene transcription profiles by qRT-PCR. R-irisin and hr-irisin both inhibited cell proliferation and activated genes related to cardiomyocyte metabolic function and differentiation, including myocardin, follistatin, smooth muscle actin, and nuclear respiratory factor-1. Signal transduction pathways affected by r-irisin in H9C2 cells and C57BL/6 mice were examined by detecting phosphorylation of PI3K-AKT, p38, ERK or STAT3. We also measured intracellular Ca2+ signaling and mitochondrial thermogenesis and energy expenditure in r-irisin-treated H9C2 cells. The results showed that r-irisin, in a certain concentration rage, could activate PI3K-AKT and intracellular Ca2+ signaling and increase cellular oxygen consumption in H9C2 cells. Our study also suggests the existence of irisin-specific receptor on the membrane of H9C2 cells. In conclusion, irisin in a certain concentration rage increased myocardial cell metabolism, inhibited cell proliferation and promoted cell differentiation. These effects might be mediated through PI3K-AKT and Ca2+ signaling, which are known to activate expression of exercise-related genes such as follistatin and myocardin. This work supports the value of exercise, which promotes irisin release.

No MeSH data available.


Related in: MedlinePlus

Stimulation of H9C2 cells with r-irisin increased intracellular Ca2+ concentration.Real-time Ca2+ imaging analysis was used to measure intracellular Ca2+ levels in H9C2 cells after stimulation with low (10 nM, A), intermediate (50 nM, B), and high (150 nM, C) r-irisin concentrations, followed by 20 mM KCl treatment. Gray lines = single cell traces; Black line = average of all cells. D: The average Ca2+ peak by each r-irisin concentration compared to basal levels prior to stimulation. Values represent the mean ± SD from 95–113 cells per concentration. (*, **and *** indicating p<0.05, p<0.01, and p<0.001 statistical differences compared to control, respectively.)
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4549318&req=5

pone.0136816.g003: Stimulation of H9C2 cells with r-irisin increased intracellular Ca2+ concentration.Real-time Ca2+ imaging analysis was used to measure intracellular Ca2+ levels in H9C2 cells after stimulation with low (10 nM, A), intermediate (50 nM, B), and high (150 nM, C) r-irisin concentrations, followed by 20 mM KCl treatment. Gray lines = single cell traces; Black line = average of all cells. D: The average Ca2+ peak by each r-irisin concentration compared to basal levels prior to stimulation. Values represent the mean ± SD from 95–113 cells per concentration. (*, **and *** indicating p<0.05, p<0.01, and p<0.001 statistical differences compared to control, respectively.)

Mentions: Elevated intracellular Ca2+ concentrations ([Ca2+]i) are critical for myocardial function and maintenance of excitation—contraction coupling, and exercise is known to stimulate Ca2+ in cardiomyocytes [29]. We hypothesized that irisin’s effects on H9C2 is exerted by increasing [Ca2+]i. To test this hypothesis, we performed real-time Ca2+ imaging analysis in H9C2 cells during stimulations with low (10 nM), intermediate (50 nM), and high (150 nM) concentrations of r-irisin. Compared with the basal Ca2+ levels, r-irisin increased [Ca2+]i approximately 4-fold and 6-fold at 10 and 50 nM, respectively (Fig 3A, 3B and 3D). Stimulation of cells with 20 mM KCl further increased [Ca2+]i treated with 10 nM r-irisin (Fig 3A), but not at 50nM or 150nM (Fig 3B and 3C).


Irisin Controls Growth, Intracellular Ca2+ Signals, and Mitochondrial Thermogenesis in Cardiomyoblasts.

Xie C, Zhang Y, Tran TD, Wang H, Li S, George EV, Zhuang H, Zhang P, Kandel A, Lai Y, Tang D, Reeves WH, Cheng H, Ding Y, Yang LJ - PLoS ONE (2015)

Stimulation of H9C2 cells with r-irisin increased intracellular Ca2+ concentration.Real-time Ca2+ imaging analysis was used to measure intracellular Ca2+ levels in H9C2 cells after stimulation with low (10 nM, A), intermediate (50 nM, B), and high (150 nM, C) r-irisin concentrations, followed by 20 mM KCl treatment. Gray lines = single cell traces; Black line = average of all cells. D: The average Ca2+ peak by each r-irisin concentration compared to basal levels prior to stimulation. Values represent the mean ± SD from 95–113 cells per concentration. (*, **and *** indicating p<0.05, p<0.01, and p<0.001 statistical differences compared to control, respectively.)
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4549318&req=5

pone.0136816.g003: Stimulation of H9C2 cells with r-irisin increased intracellular Ca2+ concentration.Real-time Ca2+ imaging analysis was used to measure intracellular Ca2+ levels in H9C2 cells after stimulation with low (10 nM, A), intermediate (50 nM, B), and high (150 nM, C) r-irisin concentrations, followed by 20 mM KCl treatment. Gray lines = single cell traces; Black line = average of all cells. D: The average Ca2+ peak by each r-irisin concentration compared to basal levels prior to stimulation. Values represent the mean ± SD from 95–113 cells per concentration. (*, **and *** indicating p<0.05, p<0.01, and p<0.001 statistical differences compared to control, respectively.)
Mentions: Elevated intracellular Ca2+ concentrations ([Ca2+]i) are critical for myocardial function and maintenance of excitation—contraction coupling, and exercise is known to stimulate Ca2+ in cardiomyocytes [29]. We hypothesized that irisin’s effects on H9C2 is exerted by increasing [Ca2+]i. To test this hypothesis, we performed real-time Ca2+ imaging analysis in H9C2 cells during stimulations with low (10 nM), intermediate (50 nM), and high (150 nM) concentrations of r-irisin. Compared with the basal Ca2+ levels, r-irisin increased [Ca2+]i approximately 4-fold and 6-fold at 10 and 50 nM, respectively (Fig 3A, 3B and 3D). Stimulation of cells with 20 mM KCl further increased [Ca2+]i treated with 10 nM r-irisin (Fig 3A), but not at 50nM or 150nM (Fig 3B and 3C).

Bottom Line: Remarkably, irisin is highly expressed in myocardium, but its physiological effects in the heart are unknown.In conclusion, irisin in a certain concentration rage increased myocardial cell metabolism, inhibited cell proliferation and promoted cell differentiation.These effects might be mediated through PI3K-AKT and Ca2+ signaling, which are known to activate expression of exercise-related genes such as follistatin and myocardin.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, Immunology, and Laboratory Medicine, University of Florida College of Medicine, Gainesville, FL, 32610, United States of America.

ABSTRACT
Exercise offers short-term and long-term health benefits, including an increased metabolic rate and energy expenditure in myocardium. The newly-discovered exercise-induced myokine, irisin, stimulates conversion of white into brown adipocytes as well as increased mitochondrial biogenesis and energy expenditure. Remarkably, irisin is highly expressed in myocardium, but its physiological effects in the heart are unknown. The objective of this work is to investigate irisin's potential multifaceted effects on cardiomyoblasts and myocardium. For this purpose, H9C2 cells were treated with recombinant irisin produced in yeast cells (r-irisin) and in HEK293 cells (hr-irisin) for examining its effects on cell proliferation by MTT [3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay and on gene transcription profiles by qRT-PCR. R-irisin and hr-irisin both inhibited cell proliferation and activated genes related to cardiomyocyte metabolic function and differentiation, including myocardin, follistatin, smooth muscle actin, and nuclear respiratory factor-1. Signal transduction pathways affected by r-irisin in H9C2 cells and C57BL/6 mice were examined by detecting phosphorylation of PI3K-AKT, p38, ERK or STAT3. We also measured intracellular Ca2+ signaling and mitochondrial thermogenesis and energy expenditure in r-irisin-treated H9C2 cells. The results showed that r-irisin, in a certain concentration rage, could activate PI3K-AKT and intracellular Ca2+ signaling and increase cellular oxygen consumption in H9C2 cells. Our study also suggests the existence of irisin-specific receptor on the membrane of H9C2 cells. In conclusion, irisin in a certain concentration rage increased myocardial cell metabolism, inhibited cell proliferation and promoted cell differentiation. These effects might be mediated through PI3K-AKT and Ca2+ signaling, which are known to activate expression of exercise-related genes such as follistatin and myocardin. This work supports the value of exercise, which promotes irisin release.

No MeSH data available.


Related in: MedlinePlus