Supplemental Tables supporting "Inhibition of mitochondrial respiration impairs nutrient consumption and metabolite transport in human retinal pigment epithelium"

In the present study, we use targeted-metabolomics and metabolite tracing with 13C glucose to investigate how inhibition of mitochondrial respiration influences the intracellular and extracellular metabolome in primary human RPE cells. Our findings demonstrate that

· Inhibition of mitochondrial metabolism causes early and unique changes in medium metabolites;

· RPE cells with dysfunctional mitochondria export less glucose, pyruvate, citrate, ketone bodies and other nutrients, but release massive amounts of lactate, hypoxanthine, and other nucleosides;

· Changes of medium metabolites consistently reflect intracellular changes.

Here we provide supplement tables, including the method we used and details in mass spectrometry.

Supports preprint: Inhibition of mitochondrial respiration impairs nutrient consumption and metabolite transport in human retinal pigment epithelium. Rui Zhang, Abbi L Engel, Yekai Wang, Bo Li, Weiyong Shen, Mark C Gillies, Jennifer Chao, Jianhai Du. bioRxiv 2020.05.11.086827; doi: https://doi.org/10.1101/2020.05.11.086827

Preprint abstract: Mitochondrial respiration in mammalian cells not only generates ATP to meet their own energy needs but also couples with biosynthetic pathways to produce metabolites that can be exported to support neighboring cells. However, how defects in mitochondrial respiration influence these biosynthetic and exporting pathways remains poorly understood. Mitochondrial dysfunction in retinal pigment epithelium (RPE) cells is an emerging contributor to the death of their neighboring photoreceptors in degenerative retinal diseases including age-related macular degeneration. In this study, we used targeted-metabolomics and 13C tracing to investigate how inhibition of mitochondrial respiration influences the intracellular and extracellular metabolome. We found inhibition of mitochondrial respiration strikingly influenced both the intracellular and extracellular metabolome in primary RPE cells. Intriguingly, the extracellular metabolic changes sensitively reflected the intracellular changes. These changes included substantially enhanced glucose consumption and lactate production, reduced release of pyruvate, citrate and ketone bodies, and massive accumulation of multiple amino acids and nucleosides. In conclusion, these findings reveal a metabolic signature of nutrient consumption and release in mitochondrial dysfunction in RPE cells. Testing medium metabolites provides a sensitive and noninvasive method to assess mitochondrial function in nutrient utilization and transport.