Limits...
Heat shock protein 22 (Hsp22) regulates oxidative phosphorylation upon its mitochondrial translocation with the inducible nitric oxide synthase in mammalian heart.

Rashed E, Lizano P, Dai H, Thomas A, Suzuki CK, Depre C, Qiu H - PLoS ONE (2015)

Bottom Line: Hsp22 overexpression in vivo stimulates cardiac mitochondrial respiration, whereas Hsp22 deletion in vivo significantly reduces respiration.Upon comparable overexpression, the N20-Hsp22 mutant did not show significant mitochondrial translocation or stimulation of mitochondrial respiration.Moreover, although N20-Hsp22 did increase global iNOS expression by 4.6-fold, it did not promote iNOS mitochondrial translocation.

View Article: PubMed Central - PubMed

Affiliation: Department of Cell Biology and Molecular Medicine, New Jersey Medical School, Rutgers, The State University of New Jersey, New Brunswick, New Jersey, United States of America.

ABSTRACT

Objectives: Stress-inducible heat shock protein 22 (Hsp22) confers protection against ischemia through induction of the inducible isoform of nitric oxide synthase (iNOS). Hsp22 overexpression in vivo stimulates cardiac mitochondrial respiration, whereas Hsp22 deletion in vivo significantly reduces respiration. We hypothesized that Hsp22-mediated regulation of mitochondrial function is dependent upon its mitochondrial translocation together with iNOS.

Methods and results: Adenoviruses harboring either the full coding sequence of Hsp22 (Ad-WT-Hsp22) or a mutant lacking a N-terminal 20 amino acid putative mitochondrial localization sequence (Ad-N20-Hsp22) were generated, and infected in rat neonatal cardiomyocytes. Compared to β-Gal control, WT-Hsp22 accumulated in mitochondria by 2.5 fold (P<0.05) and increased oxygen consumption rates by 2-fold (P<0.01). This latter effect was abolished upon addition of the selective iNOS inhibitor, 1400 W. Ad-WT-Hsp22 significantly increased global iNOS expression by about 2.5-fold (P<0.01), and also increased iNOS mitochondrial localization by 4.5 fold vs. β-gal (P<0.05). Upon comparable overexpression, the N20-Hsp22 mutant did not show significant mitochondrial translocation or stimulation of mitochondrial respiration. Moreover, although N20-Hsp22 did increase global iNOS expression by 4.6-fold, it did not promote iNOS mitochondrial translocation.

Conclusion: Translocation of both Hsp22 and iNOS to the mitochondria is necessary for Hsp22-mediated stimulation of oxidative phosphorylation.

No MeSH data available.


Related in: MedlinePlus

Mitochondrial translocation of iNOS by Hsp22.iNOS expression in total cell lysates and mitochondrial fractions from myocytes treated with Ad-WT-Hsp22 or Ad-N20-Hsp22 compared to β-Gal. *, P<0.05 vs β-Gal; #, P<0.05 vs Ad-WT-Hsp22. n = 6 per group.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4352051&req=5

pone.0119537.g007: Mitochondrial translocation of iNOS by Hsp22.iNOS expression in total cell lysates and mitochondrial fractions from myocytes treated with Ad-WT-Hsp22 or Ad-N20-Hsp22 compared to β-Gal. *, P<0.05 vs β-Gal; #, P<0.05 vs Ad-WT-Hsp22. n = 6 per group.

Mentions: We first tested whether the Ad-N20-Hsp22 mutant affects iNOS expression at a global, cellular level. RNCMs were infected with 20 moi of Ad-WT-Hsp22 or Ad-N20-Hsp22, and compared to β-Gal control. Immunoblotting for iNOS was performed using total cell lysates. Compared to β-Gal control, myocytes infected with Ad-WT-Hsp22 exhibited a significant 2.5-fold increase in global iNOS expression. Myocytes treated with Ad-N20-Hsp22 exhibited a significant global increase of iNOS expression by 4.6-fold in total cellular lysate (Fig. 7), indicating that the mutant Hsp22 did not impair the regulation of Hsp22 on iNOS gene expression. This result is consistent with the observation that the mutant Hsp22 maintains the activation of STAT3 (Fig. 3), a transcription factor known to up-regulate iNOS expression [6,10].


Heat shock protein 22 (Hsp22) regulates oxidative phosphorylation upon its mitochondrial translocation with the inducible nitric oxide synthase in mammalian heart.

Rashed E, Lizano P, Dai H, Thomas A, Suzuki CK, Depre C, Qiu H - PLoS ONE (2015)

Mitochondrial translocation of iNOS by Hsp22.iNOS expression in total cell lysates and mitochondrial fractions from myocytes treated with Ad-WT-Hsp22 or Ad-N20-Hsp22 compared to β-Gal. *, P<0.05 vs β-Gal; #, P<0.05 vs Ad-WT-Hsp22. n = 6 per group.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4352051&req=5

pone.0119537.g007: Mitochondrial translocation of iNOS by Hsp22.iNOS expression in total cell lysates and mitochondrial fractions from myocytes treated with Ad-WT-Hsp22 or Ad-N20-Hsp22 compared to β-Gal. *, P<0.05 vs β-Gal; #, P<0.05 vs Ad-WT-Hsp22. n = 6 per group.
Mentions: We first tested whether the Ad-N20-Hsp22 mutant affects iNOS expression at a global, cellular level. RNCMs were infected with 20 moi of Ad-WT-Hsp22 or Ad-N20-Hsp22, and compared to β-Gal control. Immunoblotting for iNOS was performed using total cell lysates. Compared to β-Gal control, myocytes infected with Ad-WT-Hsp22 exhibited a significant 2.5-fold increase in global iNOS expression. Myocytes treated with Ad-N20-Hsp22 exhibited a significant global increase of iNOS expression by 4.6-fold in total cellular lysate (Fig. 7), indicating that the mutant Hsp22 did not impair the regulation of Hsp22 on iNOS gene expression. This result is consistent with the observation that the mutant Hsp22 maintains the activation of STAT3 (Fig. 3), a transcription factor known to up-regulate iNOS expression [6,10].

Bottom Line: Hsp22 overexpression in vivo stimulates cardiac mitochondrial respiration, whereas Hsp22 deletion in vivo significantly reduces respiration.Upon comparable overexpression, the N20-Hsp22 mutant did not show significant mitochondrial translocation or stimulation of mitochondrial respiration.Moreover, although N20-Hsp22 did increase global iNOS expression by 4.6-fold, it did not promote iNOS mitochondrial translocation.

View Article: PubMed Central - PubMed

Affiliation: Department of Cell Biology and Molecular Medicine, New Jersey Medical School, Rutgers, The State University of New Jersey, New Brunswick, New Jersey, United States of America.

ABSTRACT

Objectives: Stress-inducible heat shock protein 22 (Hsp22) confers protection against ischemia through induction of the inducible isoform of nitric oxide synthase (iNOS). Hsp22 overexpression in vivo stimulates cardiac mitochondrial respiration, whereas Hsp22 deletion in vivo significantly reduces respiration. We hypothesized that Hsp22-mediated regulation of mitochondrial function is dependent upon its mitochondrial translocation together with iNOS.

Methods and results: Adenoviruses harboring either the full coding sequence of Hsp22 (Ad-WT-Hsp22) or a mutant lacking a N-terminal 20 amino acid putative mitochondrial localization sequence (Ad-N20-Hsp22) were generated, and infected in rat neonatal cardiomyocytes. Compared to β-Gal control, WT-Hsp22 accumulated in mitochondria by 2.5 fold (P<0.05) and increased oxygen consumption rates by 2-fold (P<0.01). This latter effect was abolished upon addition of the selective iNOS inhibitor, 1400 W. Ad-WT-Hsp22 significantly increased global iNOS expression by about 2.5-fold (P<0.01), and also increased iNOS mitochondrial localization by 4.5 fold vs. β-gal (P<0.05). Upon comparable overexpression, the N20-Hsp22 mutant did not show significant mitochondrial translocation or stimulation of mitochondrial respiration. Moreover, although N20-Hsp22 did increase global iNOS expression by 4.6-fold, it did not promote iNOS mitochondrial translocation.

Conclusion: Translocation of both Hsp22 and iNOS to the mitochondria is necessary for Hsp22-mediated stimulation of oxidative phosphorylation.

No MeSH data available.


Related in: MedlinePlus