Metabolic priming alters the morphology and metabolism of human dermal fibroblasts

The metabolic environment provided by the culture medium plays a critical role in shaping cellular function and mitochondrial activity <i>in vitro</i>. In this study, we investigated the effects of metabolic priming on the metabolism and morphology of Normal Human Dermal Fibroblasts (NHDFs) by manipulating glucose availability in the culture medium. Our strategy involved transitioning NHDFs from traditional high-glucose medium (HGm) to either a medium with physiological glucose levels (LGm) or a glucose-free, galactose-containing medium (OXm). Prior to cellular characterization, we confirmed the absence of glucose in the culture media and fetal bovine serum using ¹H nuclear magnetic resonance (NMR) spectroscopy. Given previous observations of elevated reactive species under glucose-free conditions, we explored the cellular adaptations associated with a metabolic shift from glycolysis to oxidative phosphorylation (OXPHOS). Cells cultured in OXm exhibited increased metabolic activity, elevated protein content, and substantial metabolic remodeling. Morphological analysis revealed enlargement of the cell body, cytoplasm, mitochondria, and nuclei, indicative of extensive structural adaptation. Notably, oxygen consumption rate (OCR) nearly doubled within 24 h of exposure to OXm, reflecting a rapid mitochondrial response to metabolic stress. The presence of the antioxidant N-acetyl cysteine (NAC) attenuated this increase, suggesting that redox signaling plays a key role in mitochondrial bioenergetic adaptation. These findings underscore the complex interplay between metabolic context, oxidative stress, and cellular morphology, and highlight the importance of appropriate normalization strategies in metabolic studies. See also the graphical abstract(Fig. 1).