Lactate modulates TGF-β1- and IL-1β-induced transcriptional programs in human dermal fibroblasts: Potential...

Cutaneous wounds are susceptible to metabolic imbalances, via hypoxia and the "Warburg effect," which can lead to excessive lactate accumulation, potentially delaying healing. It is also accepted that lactylation of histones and other proteins is important in the epigenetic regulation of cells. Thus, a greater understanding of how lactate affects fibroblasts could lead to new therapeutic approaches. This study aimed to investigate how lactate impacts transforming growth factor β1 (TGF-β1)- and interleukin (IL)-1β-induced transcriptional programs in normal human dermal fibroblasts (NHDFs).

Quantitative real-time PCR was used to evaluate transcriptional changes in key remodeling markers in NHDFs treated with 40 to 100 mM of sodium lactate, 0.1 μM of dexamethasone-21-phosphate, 10 mM of 2-deoxy- d -glucose, 2.5 μM of oligomycin, 10 μM of lactoyl-coenzyme A (lactyl-COA), or 10 mM of sodium acetate and then activated with 10 ng/mL of TGF-β1 or 0.1 ng/mL of IL-1β for 24 hours. Total messenger RNA was then isolated, and ΔΔCp relative expression was calculated versus appropriate controls, normalized to the housekeeping gene, GAPDH . Fluorescent membrane integrity and (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) assays were also conducted to assess toxicity and metabolic changes, respectively.

We observed that lactate dose-dependently inhibited TGF-β1-induced collagen type 1α1 ( COL1a1 ) and elastin ( ELN-1 ), as well as IL-1β-induced matrix metalloproteinase 3 ( MMP3 ) and matrix metalloproteinase 12 ( MMP12 ). The anti-inflammatory glucocorticoid, dexamethasone-21-phosphate, also inhibited cytokine-induced ELN , MMP3 , and MMP12 . Parallel analysis with 2-deoxy- d -glucose, oligomycin, lactyl-COA, and sodium acetate inferred that chromatin modifications and metabolic reprogramming may contribute to the observed lactate response in our model. In addition, metabolic reprogramming was confirmed via detection of elevated NAD(P)H-dehydrogenase activity.

These findings suggest that, because of a potential biphasic response, high lactate treatment of NHDFs exhibits immunosuppressive effects, indicating that metabolic regulation may help mitigate tissue damage. Additionally, pharmacological manipulation of histone modifications or metabolic rebalancing may serve as intriguing therapeutic interventions.