Limits...
Abnormal mitochondrial L-arginine transport contributes to the pathogenesis of heart failure and rexoygenation injury.

Williams D, Venardos KM, Byrne M, Joshi M, Horlock D, Lam NT, Gregorevic P, McGee SL, Kaye DM - PLoS ONE (2014)

Bottom Line: However, the mechanism responsible for arginine transport into mitochondria and the effect of HF on such a process is unknown.This was accompanied by significantly lower NO production and higher 3-nitrotyrosine levels (both p<0.05).The role of mitochondrial L-arginine transport in modulating cardiac stress responses was examined in cardiomyocytes with mitochondrial specific overexpression of CAT-1 (mtCAT1) exposed to hypoxia-reoxygenation stress. mtCAT1 cardiomyocytes had significantly improved mitochondrial membrane potential, respiration and ATP turnover together with significantly decreased reactive oxygen species production and cell death following mitochondrial stress.

View Article: PubMed Central - PubMed

Affiliation: Heart Failure Research Group, Baker IDI Heart & Diabetes Institute, Melbourne, Australia.

ABSTRACT

Background: Impaired mitochondrial function is fundamental feature of heart failure (HF) and myocardial ischemia. In addition to the effects of heightened oxidative stress, altered nitric oxide (NO) metabolism, generated by a mitochondrial NO synthase, has also been proposed to impact upon mitochondrial function. However, the mechanism responsible for arginine transport into mitochondria and the effect of HF on such a process is unknown. We therefore aimed to characterize mitochondrial L-arginine transport and to investigate the hypothesis that impaired mitochondrial L-arginine transport plays a key role in the pathogenesis of heart failure and myocardial injury.

Methods and results: In mitochondria isolated from failing hearts (sheep rapid pacing model and mouse Mst1 transgenic model) we demonstrated a marked reduction in L-arginine uptake (p<0.05 and p<0.01 respectively) and expression of the principal L-arginine transporter, CAT-1 (p<0.001, p<0.01) compared to controls. This was accompanied by significantly lower NO production and higher 3-nitrotyrosine levels (both p<0.05). The role of mitochondrial L-arginine transport in modulating cardiac stress responses was examined in cardiomyocytes with mitochondrial specific overexpression of CAT-1 (mtCAT1) exposed to hypoxia-reoxygenation stress. mtCAT1 cardiomyocytes had significantly improved mitochondrial membrane potential, respiration and ATP turnover together with significantly decreased reactive oxygen species production and cell death following mitochondrial stress.

Conclusion: These data provide new insights into the role of L-arginine transport in mitochondrial biology and cardiovascular disease. Augmentation of mitochondrial L-arginine availability may be a novel therapeutic strategy for myocardial disorders involving mitochondrial stress such as heart failure and reperfusion injury.

Show MeSH

Related in: MedlinePlus

Representative fluorescent confocal images of cardiomyocytes (NVCMs) transfected with control YFP-MTS AAV6 (top panels) or CAT1-YFP-MTS AAV6 (lower panels) incubated with Mitotracker Red.Images confirm mitochondrial targeting in CAT1-YFP-MTS AAV6 transfected cardiomyocytes. Scale bar = 10 µm.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4128716&req=5

pone-0104643-g004: Representative fluorescent confocal images of cardiomyocytes (NVCMs) transfected with control YFP-MTS AAV6 (top panels) or CAT1-YFP-MTS AAV6 (lower panels) incubated with Mitotracker Red.Images confirm mitochondrial targeting in CAT1-YFP-MTS AAV6 transfected cardiomyocytes. Scale bar = 10 µm.

Mentions: To extend the above observations we next aimed to investigate the potential role of mitochondrial L-arginine transport in the myocardial response to metabolic stress. To address this question we generated an adeno-associated virus (AAV) encoding CAT1-YFP-MTS that incorporates a mitochondrial targeting sequence allowing for CAT-1 overexpression specifically in the mitochondria and transfected isolated ventricular cardiomyocytes. Control transfections were performed using AAV-YFP-MTS. Expression and localisation of CAT-1 was confirmed using confocal microscopy with MitoTracker Red as shown in Figure 4.


Abnormal mitochondrial L-arginine transport contributes to the pathogenesis of heart failure and rexoygenation injury.

Williams D, Venardos KM, Byrne M, Joshi M, Horlock D, Lam NT, Gregorevic P, McGee SL, Kaye DM - PLoS ONE (2014)

Representative fluorescent confocal images of cardiomyocytes (NVCMs) transfected with control YFP-MTS AAV6 (top panels) or CAT1-YFP-MTS AAV6 (lower panels) incubated with Mitotracker Red.Images confirm mitochondrial targeting in CAT1-YFP-MTS AAV6 transfected cardiomyocytes. Scale bar = 10 µm.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4128716&req=5

pone-0104643-g004: Representative fluorescent confocal images of cardiomyocytes (NVCMs) transfected with control YFP-MTS AAV6 (top panels) or CAT1-YFP-MTS AAV6 (lower panels) incubated with Mitotracker Red.Images confirm mitochondrial targeting in CAT1-YFP-MTS AAV6 transfected cardiomyocytes. Scale bar = 10 µm.
Mentions: To extend the above observations we next aimed to investigate the potential role of mitochondrial L-arginine transport in the myocardial response to metabolic stress. To address this question we generated an adeno-associated virus (AAV) encoding CAT1-YFP-MTS that incorporates a mitochondrial targeting sequence allowing for CAT-1 overexpression specifically in the mitochondria and transfected isolated ventricular cardiomyocytes. Control transfections were performed using AAV-YFP-MTS. Expression and localisation of CAT-1 was confirmed using confocal microscopy with MitoTracker Red as shown in Figure 4.

Bottom Line: However, the mechanism responsible for arginine transport into mitochondria and the effect of HF on such a process is unknown.This was accompanied by significantly lower NO production and higher 3-nitrotyrosine levels (both p<0.05).The role of mitochondrial L-arginine transport in modulating cardiac stress responses was examined in cardiomyocytes with mitochondrial specific overexpression of CAT-1 (mtCAT1) exposed to hypoxia-reoxygenation stress. mtCAT1 cardiomyocytes had significantly improved mitochondrial membrane potential, respiration and ATP turnover together with significantly decreased reactive oxygen species production and cell death following mitochondrial stress.

View Article: PubMed Central - PubMed

Affiliation: Heart Failure Research Group, Baker IDI Heart & Diabetes Institute, Melbourne, Australia.

ABSTRACT

Background: Impaired mitochondrial function is fundamental feature of heart failure (HF) and myocardial ischemia. In addition to the effects of heightened oxidative stress, altered nitric oxide (NO) metabolism, generated by a mitochondrial NO synthase, has also been proposed to impact upon mitochondrial function. However, the mechanism responsible for arginine transport into mitochondria and the effect of HF on such a process is unknown. We therefore aimed to characterize mitochondrial L-arginine transport and to investigate the hypothesis that impaired mitochondrial L-arginine transport plays a key role in the pathogenesis of heart failure and myocardial injury.

Methods and results: In mitochondria isolated from failing hearts (sheep rapid pacing model and mouse Mst1 transgenic model) we demonstrated a marked reduction in L-arginine uptake (p<0.05 and p<0.01 respectively) and expression of the principal L-arginine transporter, CAT-1 (p<0.001, p<0.01) compared to controls. This was accompanied by significantly lower NO production and higher 3-nitrotyrosine levels (both p<0.05). The role of mitochondrial L-arginine transport in modulating cardiac stress responses was examined in cardiomyocytes with mitochondrial specific overexpression of CAT-1 (mtCAT1) exposed to hypoxia-reoxygenation stress. mtCAT1 cardiomyocytes had significantly improved mitochondrial membrane potential, respiration and ATP turnover together with significantly decreased reactive oxygen species production and cell death following mitochondrial stress.

Conclusion: These data provide new insights into the role of L-arginine transport in mitochondrial biology and cardiovascular disease. Augmentation of mitochondrial L-arginine availability may be a novel therapeutic strategy for myocardial disorders involving mitochondrial stress such as heart failure and reperfusion injury.

Show MeSH
Related in: MedlinePlus