Dorsomorphin (Compound C): Potent ATP-Competitive AMPK & BMP Signaling Inhibitor

Executive Summary: Dorsomorphin (Compound C, B3252) is a cell-permeable, reversible, ATP-competitive inhibitor of AMP-activated protein kinase (AMPK) with a Ki of 109 nM, exhibiting high selectivity over related kinases (APExBIO). It blocks AMPK activity and downstream acetyl-CoA carboxylase (ACC) phosphorylation by 80% in cell models. Dorsomorphin also inhibits bone morphogenetic protein (BMP) signaling by preventing Smad 1/5/8 phosphorylation, modulating iron metabolism and stem cell fate. The compound demonstrates clear benchmarks in in vitro and in vivo settings, including suppression of autophagic proteolysis and induction of dorsalization in zebrafish embryos (Ren et al., 2025). Its dual-pathway inhibition supports research in metabolism, autophagy, and neural differentiation, with well-established usage parameters and storage guidelines.

Biological Rationale

AMPK is a central metabolic sensor that regulates cellular energy homeostasis. Activation of AMPK enhances glucose uptake, fatty acid oxidation, and mitochondrial biogenesis. Inhibition of AMPK activity is instrumental in dissecting pathways underlying metabolic disorders, muscle atrophy, and cancer (Ren et al., 2025). BMP signaling, mediated via Smad 1/5/8 phosphorylation, controls development, stem cell fate, and iron metabolism. Dorsomorphin's dual-inhibition profile enables targeted studies of these pathways. For example, researchers have shown that pharmacological AMPK inhibition with dorsomorphin abrogates mitophagy and autophagy benefits in muscle tissue subjected to high-fat diet, clarifying causality in the AMPK/PINK1/Parkin axis. Similarly, BMP pathway blockade elucidates the role of hepcidin transcription and iron homeostasis in hepatocytes. These features position dorsomorphin as an essential tool for translational and mechanistic studies in metabolic disease, stem cell biology, and regenerative medicine (See related: Selective AMPK and BMP Pathway Inhibition; this article updates mechanistic links to iron metabolism).

Mechanism of Action of Dorsomorphin (Compound C)

Dorsomorphin acts as a reversible, ATP-competitive inhibitor of AMPK, binding to its catalytic domain with a Ki of 109 nM. This inhibition prevents downstream phosphorylation events, notably reducing ACC phosphorylation by up to 80% in cell-based assays. Dorsomorphin exhibits high selectivity for AMPK versus protein kinase A, protein kinase C, and Janus kinase 3, minimizing off-target effects at recommended concentrations (APExBIO).

In addition to AMPK inhibition, dorsomorphin suppresses BMP signaling by blocking ligand-induced phosphorylation of Smad 1/5/8. This dual action disrupts BMP4-driven gene expression (e.g., hepcidin in hepatocytes), modulates stem cell self-renewal, and impacts iron metabolism. The compound's effects on autophagy are mediated through suppression of AMPK-dependent mitophagy, with downstream consequences for mitochondrial quality control in muscle and other tissues (Ren et al., 2025).

Evidence & Benchmarks

• Dorsomorphin inhibits AMPK activity in hepatocytes and HeLa cells with a Ki of 109 nM, leading to 80% suppression of ACC phosphorylation (APExBIO, product documentation).
• The compound blocks BMP4-induced Smad 1/5/8 phosphorylation with an IC50 of 0.47 μM in cell-based assays (APExBIO).
• Dorsomorphin administration in animal models reduces hepatic hepcidin mRNA and increases serum iron levels, demonstrating modulation of iron metabolism (Ren et al., 2025).
• In zebrafish embryos, dorsomorphin induces dorsalization phenotypes by interfering with BMP signaling (Strategic Dissection of AMPK Activity—this article provides additional in vivo endpoints).
• Dorsomorphin's inhibition of AMPK abrogates mitophagy/mitochondrial remodeling induced by Lycium barbarum polysaccharide in skeletal muscle at 10 mg/kg dosing (Ren et al., 2025).
• APExBIO's B3252 product dissolves in DMSO at ≥8.49 mg/mL after gentle warming and ultrasonic treatment, but is insoluble in water or ethanol (APExBIO, product page).

Applications, Limits & Misconceptions

Typical Applications:

• Inhibition of AMPK activity in primary hepatocytes, HeLa cells, and muscle tissue (4–40 μM in vitro; 10 mg/kg IP in animal models).
• Suppression of autophagic flux and mitophagy for mechanistic studies in metabolic disease and atrophy models.
• Dissection of BMP/Smad signaling in stem cell differentiation and iron homeostasis research.
• Induction of dorsalization in zebrafish embryonic development as a functional BMP pathway readout.

Common Pitfalls or Misconceptions

• Dorsomorphin is not a pan-kinase inhibitor; it is selective for AMPK and BMP/Smad pathways at recommended concentrations (see Robust Solutions for AMPK & BMP Pathway Studies; this article clarifies selectivity windows).
• Long-term storage of DMSO solutions is not recommended; fresh solutions should be prepared before use (APExBIO).
• Compound is insoluble in water or ethanol; improper dissolution can lead to inconsistent dosing.
• At high concentrations, partial off-target inhibition of related kinases may occur; always titrate and validate in relevant models.
• Dorsomorphin effects on pathways outside AMPK or BMP signaling are not well characterized and should not be assumed without supporting data.

Workflow Integration & Parameters

Preparation and Storage: Dorsomorphin (Compound C, B3252) is supplied as a solid by APExBIO. Dissolve in DMSO at ≥8.49 mg/mL with gentle warming and ultrasonic treatment. Store solid at -20°C. Use DMSO solutions promptly; avoid repeated freeze-thaw cycles.

Recommended Usage: For cell culture, typical concentration range is 4–40 μM, depending on pathway and cell type. For animal studies, 10 mg/kg intraperitoneal injection is standard. Always validate dosing for new applications and species.

Experimental Controls: Include vehicle (DMSO) and, where possible, positive/negative pathway controls. Confirm AMPK and/or BMP signaling inhibition with direct readouts (e.g., ACC phosphorylation, Smad 1/5/8 phosphorylation).

For detailed protocol optimization and troubleshooting, see Applied Strategies for Dual AMPK & BMP/Smad Inhibition—this article extends workflow integration to include iron metabolism and mitophagy endpoints.

Conclusion & Outlook

Dorsomorphin (Compound C) is a validated, dual-pathway inhibitor essential for mechanistic studies of AMPK and BMP/Smad signaling. Its well-defined biochemical and cellular benchmarks, high selectivity, and robust performance in both in vitro and in vivo models make it a preferred tool for metabolic, autophagy, and stem cell research. APExBIO's B3252 product ensures reproducibility and quality. Ongoing studies continue to clarify its roles in disease modeling (e.g., sarcopenic obesity, cancer, and stem cell biology). Future work will likely expand validated applications and refine selectivity profiles for translational research.