(P17-032-24) Energy Metabolism in C2C12 Myoblast Cells Exposed to Marginal to Severe Iron Depletion Is Influenced by Substrate Availability

Objectives: Iron deficiency (ID) is the most prevalent nutrient deficiency and is often addressed only when associated with anemia. The WHO defines ID as serum ferritin level < 15 ng/mL in adults and < 12 ng/mL in children. Notably, individuals with a serum ferritin level between 15-30 ng/mL display symptoms of ID (impaired work capacity). This could be related to impairments in iron-related mitochondrial metabolism in skeletal muscle. The objective of this research is to establish the impact of marginal iron depletion on mitochondrial function and health.

Methods: Two mouse C2C12 myoblast models were used; first, C2C12 cells were initially plated in high-glucose DMEM medium; once adhered, medium was replaced with high-glucose DMEM medium containing 6 doses of deferoxamine (DFO), ranging from 0-100µM. Second, cells were plated according to the first model with brief modifications; after 10 hours in the high-glucose DMEM with DFO, medium was switched to low-glucose DMEM medium containing DFO (0-100µM) for 8 more hours. Following 18-hours, mitochondrial function and health were evaluated.

Results: C2C12 cells grown in high-glucose medium exhibited a positive linear relationship between iron depletion and transferrin receptor with significance at 75 and 100uM DFO concentrations. Iron depletion impaired mitochondrial respiration, increased extracellular acidification, and increased pyruvate kinase protein levels in the DFO groups starting at 12.5 or 25 µM treatments. Furthermore, iron depletion did not influence mitochondrial maximal respiration, mitochondrial mass, mitochondrial membrane potential, or protein levels of electron transport chain proteins in high-glucose medium. Cells grown in a low-glucose medium and provided palmitate-bovine serum albumin substrate exhibited reduced mitochondrial respiration and mitochondrial maximal respiration at higher DFO concentrations.

Conclusions: Our results demonstrate that acute, marginal iron depletion impairs energy metabolism through mechanisms of substrate availability; there is an increase in glycolytic favorability in myoblast cells grown in high-glucose DMEM and a decrease in the mitochondrial respiration in myoblast cells grown in low-glucose DMEM.

Funding Sources: Clemson University Creative Inquiry Program; College of Agriculture, Forestry, and Life Science Undergraduate Research Initiative