Ratiometric NAD+ sensors reveal subcellular NAD+ modulators

Mapping NAD+ dynamics in live cells and human are essential for translating NAD+ interventions into effective therapies. Yet genetically encoded NAD+ sensors with better specificity and pH-resistance are still needed for cost-effective monitoring of subcellular and clinical NAD+. We introduce multicolor, resonance energy transfer-based NAD+ sensors that cover nano- to milli-molar concentration ranges for clinical NAD+ measurement and subcellular NAD+ visualization. The sensors captured the blood NAD+ increase induced by NMN supplementation and revealed the distinct subcellular effects of NAD+ supplements and modulators. Then, the sensors enabled high-throughput screenings for mitochondrial and nucleic NAD+ modulators and identified -GPC, a cognition-related metabolite, induces NAD+ redistribution from mitochondria to nucleus relative to the total adenine nucleotides, which was confirmed by NAD+ FRET microscopy.