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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.


NADPH and NADH oxidase activities and reactive oxygen species (O2●-/H2O2) levels in perfused and non-perfused hearts.(A) NADPH oxidase, (B) NADH oxidase activities, (C) O2●-/H2O2 levels and (D) correlation between NADH oxidase activity and O2●-/H2O2 concentration in hearts perfused with KH or KH + lactate (20 mM) solutions during 120 min. Levels of O2●-/H2O2 in non-perfused hearts challenged with (E) lactate and (F) NADH. (G) Levels of O2●-/H2O2 concentration in perfused hearts challenged with acetate. Values are mean ± SE of 10 hearts; *indicates p<0.05 and **indicates p<0.01 vs. control group.
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pone.0127843.g001: NADPH and NADH oxidase activities and reactive oxygen species (O2●-/H2O2) levels in perfused and non-perfused hearts.(A) NADPH oxidase, (B) NADH oxidase activities, (C) O2●-/H2O2 levels and (D) correlation between NADH oxidase activity and O2●-/H2O2 concentration in hearts perfused with KH or KH + lactate (20 mM) solutions during 120 min. Levels of O2●-/H2O2 in non-perfused hearts challenged with (E) lactate and (F) NADH. (G) Levels of O2●-/H2O2 concentration in perfused hearts challenged with acetate. Values are mean ± SE of 10 hearts; *indicates p<0.05 and **indicates p<0.01 vs. control group.

Mentions: As lactate modulates superoxide anion production in cardiac myocytes [14], we have evaluated lactate-dependent NADH and NADPH oxidase activities in perfused hearts. No significant difference was observed in enriched membrane fraction NADPH oxidase activity of control and perfused hearts (Fig 1A). In contrast, NADH oxidase activity was significantly increased in EMM of lactate perfused hearts (Fig 1B). The increased NADH oxidase activity in hearts perfused with lactate was paralleled by significant O2●-/H2O2 production (Fig 1C). Interestingly, NADH oxidase activity and O2●-/H2O2 generation displayed a positive and significant correlation pattern (R2 = 0.90, p < 0.0001, Fig 1D). To further confirm that lactate and NADH oxidase were involved in O2●-/H2O2 production independently of perfusion condition, we pre-treated EMM of non-perfused hearts with lactate or NADH (substrate for NADH oxidase). Corroborating data obtained on the perfused hearts, both lactate (Fig 1E) and NADH (Fig 1F) significantly increased O2●-/H2O2 production in EMM. In order to test whether elevated levels of O2●-/H2O2 in lactate perfused hearts would be specific and not a byproduct of increased carbon metabolism, we have perfused hearts with acetate, another monocarboxylate. As shown in Fig 1G, no significant difference was detected in O2●-/H2O2 production in acetate perfused EMM confirming the lactate-dependent effect in heart´s EMM O2●-/H2O2 production.


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)

NADPH and NADH oxidase activities and reactive oxygen species (O2●-/H2O2) levels in perfused and non-perfused hearts.(A) NADPH oxidase, (B) NADH oxidase activities, (C) O2●-/H2O2 levels and (D) correlation between NADH oxidase activity and O2●-/H2O2 concentration in hearts perfused with KH or KH + lactate (20 mM) solutions during 120 min. Levels of O2●-/H2O2 in non-perfused hearts challenged with (E) lactate and (F) NADH. (G) Levels of O2●-/H2O2 concentration in perfused hearts challenged with acetate. Values are mean ± SE of 10 hearts; *indicates p<0.05 and **indicates p<0.01 vs. control group.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0127843.g001: NADPH and NADH oxidase activities and reactive oxygen species (O2●-/H2O2) levels in perfused and non-perfused hearts.(A) NADPH oxidase, (B) NADH oxidase activities, (C) O2●-/H2O2 levels and (D) correlation between NADH oxidase activity and O2●-/H2O2 concentration in hearts perfused with KH or KH + lactate (20 mM) solutions during 120 min. Levels of O2●-/H2O2 in non-perfused hearts challenged with (E) lactate and (F) NADH. (G) Levels of O2●-/H2O2 concentration in perfused hearts challenged with acetate. Values are mean ± SE of 10 hearts; *indicates p<0.05 and **indicates p<0.01 vs. control group.
Mentions: As lactate modulates superoxide anion production in cardiac myocytes [14], we have evaluated lactate-dependent NADH and NADPH oxidase activities in perfused hearts. No significant difference was observed in enriched membrane fraction NADPH oxidase activity of control and perfused hearts (Fig 1A). In contrast, NADH oxidase activity was significantly increased in EMM of lactate perfused hearts (Fig 1B). The increased NADH oxidase activity in hearts perfused with lactate was paralleled by significant O2●-/H2O2 production (Fig 1C). Interestingly, NADH oxidase activity and O2●-/H2O2 generation displayed a positive and significant correlation pattern (R2 = 0.90, p < 0.0001, Fig 1D). To further confirm that lactate and NADH oxidase were involved in O2●-/H2O2 production independently of perfusion condition, we pre-treated EMM of non-perfused hearts with lactate or NADH (substrate for NADH oxidase). Corroborating data obtained on the perfused hearts, both lactate (Fig 1E) and NADH (Fig 1F) significantly increased O2●-/H2O2 production in EMM. In order to test whether elevated levels of O2●-/H2O2 in lactate perfused hearts would be specific and not a byproduct of increased carbon metabolism, we have perfused hearts with acetate, another monocarboxylate. As shown in Fig 1G, no significant difference was detected in O2●-/H2O2 production in acetate perfused EMM confirming the lactate-dependent effect in heart´s EMM O2●-/H2O2 production.

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.