Background: Molybdenum is an essential micronutrient and critical cofactor within proteins, including molybdoenzymes, integral proteins in redox reactions and the oxidative stress response. However, molybdenum remains an understudied micronutrient in placental physiology. Previous work from our lab found dysregulation in the molybdenum metabolism in placentas from complicated pregnancies. Therefore, this study aimed to investigate the effects of molybdenum supplementation on cell growth and mitochondrial function in the HTR-8/SVneo trophoblast cell line. We hypothesised that molybdenum supplementation can modulate essential physiological pathways, including the antioxidant response and cell proliferation.
Methods: The HTR-8/SVneo trophoblast cell line was cultured with ammonium and sodium molybdate salts at a concentration range designed to reflect physiological (10nM-10uM), and supraphysiological (1mM) molybdenum levels. Cell growth curves were generated using an image-based, phase-contrast method (Incucyte software), and metabolism was assessed via mitochondrial respiration using the Seahorse XF Analyzer. Real-time PCR analysis was used to determine the expression of molybdoenzymes and associated signalling pathways.
Results: Cell growth (p<0.05) and mitochondrial maximum respiratory capacity (p<0.01) were significantly reduced following ammonium molybdate supraphysiological supplementation. Ammonium molybdate and sodium molybdate supplementation did not inhibit or aid cell growth. Similarly, mitochondrial respiration was not altered by ammonium or sodium molybdate supplementation at physiological levels. Superoxide Dismutase 2 expression increased significantly (p<0.05) with 5μM treatment (p<0.05) of sodium molybdate.
Conclusion: In a model not exposed to stress, and supplementation at physiological levels, sodium molybdate and ammonium molybdate did not have significant impact on growth and mitochondrial function. However, our PCR results indicate potential modulation of the antioxidant cell response following sodium molybdate treatment at a high physiological concentration. This research is integral for evaluating the role of molybdenum in placental physiology in a healthy model; we postulate that molybdenum supplementation may exert a protective effect following oxidative insult as seen in pathological pregnancies.