Limits...
Lactate up-regulates the expression of lactate oxidation complex-related genes in left ventricular cardiac tissue of rats.

Gabriel-Costa D, da Cunha TF, Bechara LR, Fortunato RS, Bozi LH, Coelho Mde A, Barreto-Chaves ML, Brum PC - PLoS ONE (2015)

Bottom Line: This response was associated with increased cardiac O2●-/H2O2 levels and up-regulation of MCT1, MCT4, LDH and PGC1α with no changes in HK, PDH, CS, COXIV mRNA levels and mitochondrial DNA levels.Our results provide evidence for lactate-induced up-regulation of lactate oxidation complex associated with increased NADH oxidase activity and cardiac O2●-/H2O2 driving to an anti-oxidant response.These results unveil lactate as an important signaling molecule regulating components of the lactate oxidation complex in cardiac muscle.

View Article: PubMed Central - PubMed

Affiliation: School of physical Education and Sport, University of São Paulo, São Paulo, Brazil.

ABSTRACT

Background: Besides its role as a fuel source in intermediary metabolism, lactate has been considered a signaling molecule modulating lactate-sensitive genes involved in the regulation of skeletal muscle metabolism. Even though the flux of lactate is significantly high in the heart, its role on regulation of cardiac genes regulating lactate oxidation has not been clarified yet. We tested the hypothesis that lactate would increase cardiac levels of reactive oxygen species and up-regulate the expression of genes related to lactate oxidation complex.

Methods/principal findings: Isolated hearts from male adult Wistar rats were perfused with control, lactate or acetate (20mM) added Krebs-Henseleit solution during 120 min in modified Langendorff apparatus. Reactive oxygen species (O2●-/H2O2) levels, and NADH and NADPH oxidase activities (in enriched microsomal or plasmatic membranes, respectively) were evaluated by fluorimetry while SOD and catalase activities were evaluated by spectrophotometry. mRNA levels of lactate oxidation complex and energetic enzymes MCT1, MCT4, HK, LDH, PDH, CS, PGC1α and COXIV were quantified by real time RT-PCR. Mitochondrial DNA levels were also evaluated. Hemodynamic parameters were acquired during the experiment. The key findings of this work were that lactate elevated cardiac NADH oxidase activity but not NADPH activity. This response was associated with increased cardiac O2●-/H2O2 levels and up-regulation of MCT1, MCT4, LDH and PGC1α with no changes in HK, PDH, CS, COXIV mRNA levels and mitochondrial DNA levels. Lactate increased NRF-2 nuclear expression and SOD activity probably as counter-regulatory responses to increased O2●-/H2O2.

Conclusions: Our results provide evidence for lactate-induced up-regulation of lactate oxidation complex associated with increased NADH oxidase activity and cardiac O2●-/H2O2 driving to an anti-oxidant response. These results unveil lactate as an important signaling molecule regulating components of the lactate oxidation complex in cardiac muscle.

No MeSH data available.


Activities of antioxidant enzymes and gene expression.Activities of (A) catalase and (B) SOD. mRNA levels of (C) NRF-1, (D) NRF-2, (E) SOD1, (F) SOD2 and (G) SOD3. (H) Nuclear NRF-2 expression in hearts perfused with KH or KH + lactate (20 mM) solutions during 120 min. Values are mean ± SE of 6–9 hearts; *indicates p<0.05 vs. control group.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4440754&req=5

pone.0127843.g002: Activities of antioxidant enzymes and gene expression.Activities of (A) catalase and (B) SOD. mRNA levels of (C) NRF-1, (D) NRF-2, (E) SOD1, (F) SOD2 and (G) SOD3. (H) Nuclear NRF-2 expression in hearts perfused with KH or KH + lactate (20 mM) solutions during 120 min. Values are mean ± SE of 6–9 hearts; *indicates p<0.05 vs. control group.

Mentions: To test whether increased levels of cardiac O2●-/H2O2 after lactate would activate antioxidant system defense, we have quantified the activity of the antioxidant enzymes, SOD and catalase. As shown in Fig 2A lactate perfusion had no impact on catalase activity. In contrast, SOD activity was significantly increased (Fig 2B). Although no difference was observed in NRF-1 (Fig 2C) and NRF-2 (Fig 2D) (transcription factors that up-regulate SOD gene expression) and SOD isoform mRNA levels (SOD 1, 2 and 3) in lactate perfused hearts (Fig 2E–2G). A significant increase in nuclear-NRF2 expression was observed in lactate perfused hearts (Fig 2H), which suggests that lactate might activate anti-oxidant response element (ARE) signaling cascades.


Lactate up-regulates the expression of lactate oxidation complex-related genes in left ventricular cardiac tissue of rats.

Gabriel-Costa D, da Cunha TF, Bechara LR, Fortunato RS, Bozi LH, Coelho Mde A, Barreto-Chaves ML, Brum PC - PLoS ONE (2015)

Activities of antioxidant enzymes and gene expression.Activities of (A) catalase and (B) SOD. mRNA levels of (C) NRF-1, (D) NRF-2, (E) SOD1, (F) SOD2 and (G) SOD3. (H) Nuclear NRF-2 expression in hearts perfused with KH or KH + lactate (20 mM) solutions during 120 min. Values are mean ± SE of 6–9 hearts; *indicates p<0.05 vs. control group.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4440754&req=5

pone.0127843.g002: Activities of antioxidant enzymes and gene expression.Activities of (A) catalase and (B) SOD. mRNA levels of (C) NRF-1, (D) NRF-2, (E) SOD1, (F) SOD2 and (G) SOD3. (H) Nuclear NRF-2 expression in hearts perfused with KH or KH + lactate (20 mM) solutions during 120 min. Values are mean ± SE of 6–9 hearts; *indicates p<0.05 vs. control group.
Mentions: To test whether increased levels of cardiac O2●-/H2O2 after lactate would activate antioxidant system defense, we have quantified the activity of the antioxidant enzymes, SOD and catalase. As shown in Fig 2A lactate perfusion had no impact on catalase activity. In contrast, SOD activity was significantly increased (Fig 2B). Although no difference was observed in NRF-1 (Fig 2C) and NRF-2 (Fig 2D) (transcription factors that up-regulate SOD gene expression) and SOD isoform mRNA levels (SOD 1, 2 and 3) in lactate perfused hearts (Fig 2E–2G). A significant increase in nuclear-NRF2 expression was observed in lactate perfused hearts (Fig 2H), which suggests that lactate might activate anti-oxidant response element (ARE) signaling cascades.

Bottom Line: This response was associated with increased cardiac O2●-/H2O2 levels and up-regulation of MCT1, MCT4, LDH and PGC1α with no changes in HK, PDH, CS, COXIV mRNA levels and mitochondrial DNA levels.Our results provide evidence for lactate-induced up-regulation of lactate oxidation complex associated with increased NADH oxidase activity and cardiac O2●-/H2O2 driving to an anti-oxidant response.These results unveil lactate as an important signaling molecule regulating components of the lactate oxidation complex in cardiac muscle.

View Article: PubMed Central - PubMed

Affiliation: School of physical Education and Sport, University of São Paulo, São Paulo, Brazil.

ABSTRACT

Background: Besides its role as a fuel source in intermediary metabolism, lactate has been considered a signaling molecule modulating lactate-sensitive genes involved in the regulation of skeletal muscle metabolism. Even though the flux of lactate is significantly high in the heart, its role on regulation of cardiac genes regulating lactate oxidation has not been clarified yet. We tested the hypothesis that lactate would increase cardiac levels of reactive oxygen species and up-regulate the expression of genes related to lactate oxidation complex.

Methods/principal findings: Isolated hearts from male adult Wistar rats were perfused with control, lactate or acetate (20mM) added Krebs-Henseleit solution during 120 min in modified Langendorff apparatus. Reactive oxygen species (O2●-/H2O2) levels, and NADH and NADPH oxidase activities (in enriched microsomal or plasmatic membranes, respectively) were evaluated by fluorimetry while SOD and catalase activities were evaluated by spectrophotometry. mRNA levels of lactate oxidation complex and energetic enzymes MCT1, MCT4, HK, LDH, PDH, CS, PGC1α and COXIV were quantified by real time RT-PCR. Mitochondrial DNA levels were also evaluated. Hemodynamic parameters were acquired during the experiment. The key findings of this work were that lactate elevated cardiac NADH oxidase activity but not NADPH activity. This response was associated with increased cardiac O2●-/H2O2 levels and up-regulation of MCT1, MCT4, LDH and PGC1α with no changes in HK, PDH, CS, COXIV mRNA levels and mitochondrial DNA levels. Lactate increased NRF-2 nuclear expression and SOD activity probably as counter-regulatory responses to increased O2●-/H2O2.

Conclusions: Our results provide evidence for lactate-induced up-regulation of lactate oxidation complex associated with increased NADH oxidase activity and cardiac O2●-/H2O2 driving to an anti-oxidant response. These results unveil lactate as an important signaling molecule regulating components of the lactate oxidation complex in cardiac muscle.

No MeSH data available.