Mechanism of Action
Pan-ERR Nuclear Receptor Agonism
ERRalpha, ERRbeta, and ERRgamma are orphan nuclear receptors that regulate transcriptional programs for mitochondrial function and energy metabolism. Unlike estrogen receptors (ERs), ERRs do not require estrogen as a ligand, they are constitutively active transcription factors. SLU-PP-332 binds to all three ERR isoforms and enhances their transcriptional activity by stabilizing coactivator recruitment, particularly PGC-1alpha and PGC-1beta. PGC-1alpha is the master regulator of mitochondrial biogenesis - its activation drives the entire downstream program of aerobic capacity enhancement: more mitochondria, increased OXPHOS complex density, enhanced fatty acid oxidation, and Type I fiber gene expression (myosin heavy chain 7, troponin I slow).
Metabolic Profile of ERR Activation
ERR activation mimics the transcriptional response to sustained aerobic exercise at the gene expression level. Treated mice show increased expression of genes for: OXPHOS complexes I-V, fatty acid transport (CD36, FABP3), beta-oxidation enzymes (HADHA, ACADL), and Type I myosin isoforms. The net effect is skeletal muscle that relies more heavily on fat oxidation, similar to the metabolic shift seen after months of endurance training. This is theoretically relevant to obesity (enhanced fat burning), metabolic syndrome (improved insulin sensitivity), and heart failure (reduced cardiac metabolic dysfunction).
Research Summary
2024 Mouse Exercise Mimetic Study
EmergingThe 2024 JPET paper (Petrick et al) showed mice treated with SLU-PP-332 for 4 weeks ran 70% farther on a treadmill test than vehicle controls, with measurably higher maximum running speed. Muscle biopsies confirmed increased Type I fiber markers and mitochondrial density. Body composition improved (reduced fat mass) without dietary changes. This was a small, short-duration preclinical study in healthy young mice, not a disease model, not aged animals, and not a cardiac or metabolic disease context where ERR activation might show stronger therapeutic signal.
Cardiac and Heart Failure Research
EmergingEarlier ERR agonist work from the same WashU lab showed cardiac benefits in heart failure models, ERR activation restored the normal cardiac metabolic switch from fats to glucose that goes awry in failing hearts. SLU-PP-332 or related compounds improved ejection fraction and reduced cardiac hypertrophy in pressure-overload mouse models. This may represent the more near-term therapeutic application for this class than healthy exercise enhancement.
Calculate your SLU-PP-332 dose Vial strength, BAC water, exact syringe draw in IU. Free, no signup. Open Calc →
Research Protocols
| Goal | Dose | Frequency | Route |
|---|---|---|---|
| Exercise mimetic (mouse study) | 10-30 mg/kg/day oral | Daily for 4 weeks | Oral (mouse only, no human dose established) |
| Heart failure model (mouse study) | 10 mg/kg/day | Daily | Oral (mouse only) |
| Human protocol | Not established | Unknown | No human trials conducted |
SLU-PP-332 has no established human dosing. Mouse-to-human allometric scaling of 10 mg/kg would suggest very high human doses, but ERR biology may be far more potent in humans. Approach with extreme caution, this is a very early-stage compound with unknown human pharmacology and potential for off-target nuclear receptor interactions.
Interactions
Safety Profile
No human safety data exists for SLU-PP-332. In rodent studies at pharmacologically active doses, no gross toxicity, organ pathology, or weight loss beyond the intended metabolic effect was reported. The key theoretical concerns are: 1) ERR isoforms regulate multiple tissue functions including bone, immune, and reproductive biology, pan-ERR agonism may have off-target effects in these systems at high doses; 2) ERRgamma is particularly highly expressed in cardiac tissue and has complex role in cardiac hypertrophy pathways - long-term activation effects are unknown; 3) drug-drug interactions via nuclear receptor competition with other ligand-activated receptors (ERs, PPARs) are unstudied in humans. Until human PK/PD and safety studies are published, extreme caution is warranted. Not WADA tested. Not FDA approved. Not a peptide - a small molecule.
References
- [1]Petrick HL et al. "The ERR pan-agonist SLU-PP-332 increases exercise capacity in mice through effects in skeletal muscle." J Pharmacol Exp Ther. 2024;388(2):477-488.
- [2]Rangwala SM et al. "Estrogen-related receptor gamma is a key regulator of muscle mitochondrial activity and oxidative capacity." J Biol Chem. 2010;285(29):22619-22629.
- [3]Huss JM et al. "Estrogen-related receptor alpha directs peroxisome proliferator-activated receptor alpha signaling in the transcriptional control of energy metabolism in cardiac and skeletal muscle." Mol Cell Biol. 2004;24(20):9079-9091.