This hypothesis proposes that targeting CD38, the primary NAD+-consuming enzyme, represents a more direct therapeutic approach to metabolic dysfunction than NAD+ precursor supplementation. CD38 expression increases dramatically with aging and inflammation, creating a futile cycle where enhanced NAD+ consumption outpaces biosynthetic capacity. Rather than attempting to replenish NAD+ pools through precursor loading, selective CD38 inhibition would preserve endogenous NAD+ levels by blocking its enzymatic degradation. This approach targets the root cause of NAD+ depletion rather than compensating for it. The hypothesis predicts that CD38 inhibitors like 78c or apigenin will restore NAD+/NADH ratios more effectively than nicotinamide riboside or nicotinamide mononucleotide supplementation. By preserving NAD+ availability, CD38 inhibition would maintain SIRT1/3 deacetylase activity, support mitochondrial biogenesis, and prevent the metabolic shift toward glycolysis characteristic of cellular senescence. This mechanism would be particularly relevant in tissues with high CD38 expression during aging, including immune cells, endothelial cells, and adipose tissue.
...Curated pathway from expert analysis
flowchart TD
A["DNA Single-Strand Breaks<br/>Oxidative Stress in AD"]
B["PARP1 Hyperactivation<br/>PAR Polymer Synthesis"]
C["NAD+ Depletion<br/>40-60% Loss in AD"]
D["SIRT1 Inactivation<br/>Deacetylase Impaired"]
E["PGC1alpha Inactivation<br/>Mitochondrial Biogenesis Loss"]
F["Energy Failure<br/>Neuronal Death"]
G["PARP1 Inhibitor<br/>Olaparib/Veliparib"]
A --> B
B --> C
C --> D
D --> E
E --> F
G -.->|"blocks"| B
style A fill:#b71c1c,stroke:#ef9a9a,color:#ef9a9a
style F fill:#b71c1c,stroke:#ef9a9a,color:#ef9a9a
style G fill:#1a237e,stroke:#4fc3f7,color:#4fc3f7No linked papers recorded for this hypothesis yet.
Median TPM across 13 brain regions for CD38, SIRT1/3 from GTEx v10.
No clinical trials data linked to this hypothesis yet.
No curated ClinVar variants loaded for this hypothesis.
Run scripts/backfill_clinvar_variants.py to fetch P/LP/VUS variants.
No DepMap CRISPR Chronos data found for CD38, SIRT1.
Run python3 scripts/backfill_hypothesis_depmap.py to populate.
| Prediction | Predicted | Observed | Status | Conf |
|---|---|---|---|---|
| IF primary senescent human endothelial cells (HUVECs induced to senescence by replicated stress or ionizing radiation) are treated with CD38 inhibitor (apigenin, 10 µM) for 2 weeks, THEN cellular oxyg | Seahorse XFe96 bioenergetics profiling will reveal: (1) basal OCR increase from ~30 pmol/min to ≥39 pmol/min; (2) spare respiratory capacity increase from ~15 p | — no observation — | pending | 0.55 |
| IF aged mice (18-22 months) with metabolic dysfunction are treated with a selective CD38 inhibitor (78c, 10 mg/kg/day) versus equimolar nicotinamide riboside supplementation for 8 weeks, THEN the CD38 | Liver NAD+/NADH ratio will increase by ≥40% from baseline in the CD38 inhibitor group versus ≤20% increase in the NR supplementation group, as measured by liqui | — no observation — | pending | 0.65 |