L-Lactate Protects Skin Fibroblasts against Aging-Associated Mitochondrial Dysfunction via Mitohormesis

Figure 1

The effect of L-lactate on respiration, H₂O₂ production, and metabolism of skin fibroblasts. (a) Relative production of H₂O₂ from intact fibroblasts measured with Amplex Red before (CTRL) and after (LAC) the addition of 5 mM L-lactate. (b) Representative spectrofluorimetric track from the same measurement. (c) Respiration of intact fibroblasts in complete media before (CTRL) and after (LAC) addition of 5 mM L-lactate. (d) Relative production of ROS (superoxide and peroxonitrite) in mitochondrial matrix of intact fibroblasts measured with MitoSOX before (CTRL) and after (LAC) the addition of 5 mM L-lactate. (e) Intracellular concentrations of L-lactate in fibroblasts cultured in complete media before (CTRL) and after (LAC) addition of 5 mM L-lactate. (f) Relative increase in the intracellular levels of selected metabolites after the addition of 5 mM L-lactate (dashed line: value for L-lactate). (g) Scheme of L-lactate utilization in the cell. LAC: lactate; PYR: pyruvate; CIT: citrate; ICI: isocitrate; 2-OG: 2-oxoglutarate; 2-HG: 2-hydroxyglutarate; SUC: succinate; FUM: fumarate; MAL: malate; OXA: oxaloacetate; Ac: acetyl; LDH: lactate dehydrogenase; LOX: lactate oxidase; PC: pyruvate carboxylase; PDH: pyruvate dehydrogenase (^∗significantly different from CTRL, ; ^#significantly different from L-lactate, ).

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