SLU-PP-332: An ERR Pan-Agonist Studied as an Exercise Mimetic

Research summary. SLU-PP-332 is a synthetic small molecule (not a peptide) developed at Saint Louis University as a pan-agonist of the estrogen-related receptor (ERR) family — ERRα, ERRβ, and ERRγ. ERRs are orphan nuclear receptors that drive transcriptional programmes in mitochondrial biogenesis, oxidative phosphorylation, and fatty-acid oxidation, and are central to the metabolic adaptations associated with endurance exercise. SLU-PP-332 has drawn substantial interest as a research "exercise mimetic" because it reproduces a subset of the metabolic-adaptation signatures of endurance training in rodent models without the mechanical training stimulus.

Note: SLU-PP-332 is a small-molecule research compound, not a peptide. It is included in this collection because it appears alongside peptides in metabolic-research catalogues, but its pharmacology and supply considerations differ.

Molecular profile

• Class: Synthetic small-molecule estrogen-related receptor (ERR) pan-agonist
• Targets: ERRα, ERRβ, ERRγ (with ERRα the most extensively characterised target)
• Origin: Burris laboratory, Saint Louis University; reported in the published literature from approximately 2020 onward
• Distinction: SLU-PP-332 is a small molecule — not a peptide — and follows small-molecule rather than peptide pharmacokinetics

Mechanism of action

SLU-PP-332 is reported to act as an agonist of the ERR family of orphan nuclear receptors, with downstream effects centred on the ERR / PGC-1α transcriptional axis:

• ERRα/β/γ agonism. ERRs are nuclear receptors that operate without an identified endogenous ligand, but their transcriptional activity is strongly modulated by interaction with the PGC-1α coactivator — the "master regulator" of mitochondrial biogenesis. SLU-PP-332 stabilises the active conformation of the receptor and supports ERR/PGC-1α-driven transcription.
• Mitochondrial biogenesis. Reported downstream effects include increased expression of nuclear-encoded mitochondrial genes, mitochondrial DNA copy number, and mitochondrial protein content in skeletal muscle and cardiac tissue.
• Fatty-acid oxidation. Reported increases in expression and activity of fatty-acid oxidation enzymes, with corresponding increases in lipid utilisation as an energy substrate.
• Glucose handling. Reported improvements in insulin sensitivity in rodent obesity and insulin-resistance models, attributed to improved oxidative capacity in skeletal muscle.
• Type-I-fibre shift. Some reports describe shifts in skeletal-muscle fibre-type composition consistent with the chronic-endurance-training-like phenotype.

The mechanistic picture is that SLU-PP-332 reproduces a substantial fraction of the transcriptional exercise response without producing the mechanical exercise stimulus.

Preclinical research highlights

Rodent obesity and insulin-resistance models. Reports include reductions in body weight, improvements in glucose tolerance, and improvements in lipid handling in diet-induced-obesity rodent models.

Endurance-performance endpoints. Rodent treadmill-running studies have reported substantial improvements in time-to-exhaustion in sedentary animals receiving SLU-PP-332, supporting the "exercise mimetic" framing.

Hepatic steatosis. Reported reductions in hepatic triglyceride accumulation in fatty-liver-disease rodent models.

Cardiac-energetics endpoints. Reported effects on cardiac mitochondrial content and oxidative capacity in rodent models, with implications for cardiac-energetics research in heart-failure-with-preserved-ejection-fraction-style models.

Aged-rodent endpoints. Reports of improvements in metabolic and functional endpoints in aged rodents, framed in the context of age-related mitochondrial decline.

Limitations of the evidence base

• The published SLU-PP-332 literature is concentrated in a relatively small number of investigators (initially the originating Burris lab) and is recent.
• Most data is from rodent models; human clinical evidence is essentially absent.
• The long-term effects of chronic ERR pan-agonism — particularly on tissue homeostasis in non-target organs — remain incompletely characterised.
• The "exercise mimetic" framing is mechanistically interesting but does not capture the full systemic adaptations associated with actual exercise training.

Current research status

SLU-PP-332 is an investigational research compound. It is not approved by the FDA for any indication and is not in late-stage clinical development at present. It is available through research-chemical suppliers as a research-grade investigational compound and is not intended for self-administration.

Key takeaways for researchers

• SLU-PP-332 is a small-molecule (not a peptide) ERRα/β/γ pan-agonist developed at Saint Louis University.
• It engages the ERR / PGC-1α transcriptional axis, reproducing a subset of the transcriptional signatures of endurance exercise.
• Reported preclinical effects include increased mitochondrial biogenesis, increased fatty-acid oxidation, improved insulin sensitivity, reduced hepatic steatosis, and increased rodent treadmill endurance.
• The literature is recent and predominantly rodent-based; long-term and human data are lacking.
• SLU-PP-332 is not an FDA-approved drug; research-grade material is for laboratory use only.

References

1. Billon C, Schoepke E, Avdagic A, Chatterjee A, Butler AA, Elgendy B, Walker JK, Burris TP. A synthetic ERR agonist alleviates metabolic syndrome. J Pharmacol Exp Ther. 2024;388(2):232–240.
2. Billon C, Chatterjee A, Avdagic A, Schoepke E, Pollack S, Banerjee S, Walker JK, Elgendy B, Burris TP. Pharmacological activation of estrogen receptor-related receptor stimulates oxidative metabolism and improves endurance capacity. J Pharmacol Exp Ther. 2023;384(3):422–432.

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This article is provided for educational and research purposes only. SLU-PP-332 is a research compound. It is not an approved drug or therapeutic agent and is not intended for human consumption, diagnosis, treatment, cure, or prevention of any disease or condition. All work involving this compound should be conducted by qualified personnel within an appropriate research setting and in compliance with applicable institutional and regulatory requirements.