Dorsomorphin (Compound C): ATP-Competitive AMPK and BMP/Smad Inhibitor for Translational Research

Executive Summary: Dorsomorphin (Compound C, B3252) is an ATP-competitive AMPK inhibitor with a Ki of 109 nM and high selectivity over related kinases (APExBIO). It potently suppresses downstream ACC phosphorylation (~80% inhibition) and autophagic proteolysis in cellular models. Dorsomorphin also inhibits BMP signaling by blocking Smad1/5/8 phosphorylation, affecting processes like neural induction and iron metabolism. The compound is widely used in research for pathway dissection, with documented limitations regarding specificity at high concentrations. Benchmark applications include inhibition of AMPK in hepatocytes and modulation of hepcidin expression in animal models (Patra et al., 2020).

Biological Rationale

AMP-activated protein kinase (AMPK) is a key regulator of cellular energy homeostasis, activated under metabolic stress conditions. It orchestrates downstream events such as autophagy, fatty acid oxidation, and glucose uptake. Dysregulation of AMPK and related signaling pathways is implicated in metabolic disorders, cancer, and neurodegeneration (Patra et al., 2020). Bone morphogenetic protein (BMP) signaling, via the Smad1/5/8 axis, controls developmental processes, stem cell fate, and tissue regeneration. Pharmacological modulation of these pathways enables mechanistic dissection of cellular responses to energy deprivation, redox stress, and differentiation cues. Dorsomorphin provides a targeted approach to interrogate AMPK and BMP/Smad functions in both in vitro and in vivo models (see strategic leveraging analysis: Dorsomorphin (Compound C)). This article builds upon such insights by providing a tightly benchmarked, fact-rich resource for experimental planning.

Mechanism of Action of Dorsomorphin (Compound C)

Dorsomorphin is a cell-permeable, reversible inhibitor that competitively binds the ATP site of AMPK, blocking its kinase activity (Ki = 109 nM, measured at 23°C in kinase buffer). It displays high selectivity for AMPK over protein kinase A, protein kinase C, and Janus kinase 3 at equivalent concentrations (see selectivity discussion). Mechanistically, dorsomorphin suppresses phosphorylation of key AMPK substrates, notably acetyl-CoA carboxylase (ACC), with up to 80% reduction in cellular assays (HeLa cells, 10 μM, 2 h exposure). In addition, dorsomorphin inhibits BMP type I receptor kinases, thereby blocking phosphorylation of Smad1/5/8 proteins. This dual pathway inhibition leads to reduced autophagic proteolysis, decreased hepatic hepcidin transcription, and altered neural stem cell differentiation (mechanisms and applications overview).

Evidence & Benchmarks

• Dorsomorphin inhibits AMPK activity in hepatocytes and HeLa cells with a reported IC₅₀ of 0.1–0.5 μM (HeLa, 37°C, 1 h incubation) (Patra et al., 2020).
• Selective inhibition of ACC phosphorylation by 80% at 10 μM dorsomorphin in cultured cells (HeLa, 37°C, 2 h) (Patra et al., 2020).
• Inhibition of BMP4-induced SMAD phosphorylation in C2C12 cells, IC₅₀ = 0.47 μM (serum-free medium, 30 min pre-treatment) (APExBIO).
• Reduces hepatic hepcidin mRNA and increases serum iron in mouse models at 10 mg/kg intraperitoneal injection (C57BL/6 mice, n=6, 6 h post-dose) (Patra et al., 2020).
• Promotes neural induction and self-renewal in human embryonic stem cells by inhibiting BMP signaling (hESC, 4 μM, 48 h, neural culture conditions) (APExBIO).
• Induces dorsalization in zebrafish embryos, confirming in vivo pathway activity (zebrafish, 10 μM, single dose at 2 hpf) (APExBIO).

These findings extend prior summaries (see strategic deployment review) by providing precise quantitative benchmarks under defined experimental conditions.

Applications, Limits & Misconceptions

Dorsomorphin is widely used in metabolic research, cancer biology, and regenerative medicine. Applications include:

• Dissection of the AMPK signaling pathway in metabolic stress and autophagy models.
• Inhibition of BMP/Smad signaling in developmental and stem cell studies.
• Modulation of iron metabolism via hepatic hepcidin suppression.
• Analysis of pathway crosstalk in disease models (e.g., cancer, muscle atrophy).

For a comprehensive translational strategy, see Redefining Translational Strategy: Leveraging Dual AMPK and BMP Inhibition, which expands on Dorsomorphin's use in metabolic disease and regenerative contexts.

Common Pitfalls or Misconceptions

• Dorsomorphin is not selective for AMPK at concentrations above 10 μM, as off-target effects on other kinases may emerge.
• It is insoluble in water and ethanol; only use DMSO (≥8.49 mg/mL with warming/sonication) for stock solutions.
• Long-term storage of solutions is not recommended; prepare fresh working stocks before each experiment.
• Not suitable for chronic in vivo dosing without pharmacokinetic optimization; rapid clearance and limited bioavailability may confound results.
• Does not directly modulate redox-sensitive Nrf2 signaling but impacts related metabolic and autophagic pathways (Patra et al., 2020).

Workflow Integration & Parameters

Dorsomorphin (Compound C, B3252) from APExBIO is supplied as a solid, to be stored at -20°C (product page). For cell culture, recommended concentrations range from 4–40 μM (DMSO vehicle, final DMSO ≤0.1%). In animal studies, 10 mg/kg is administered via intraperitoneal injection. Solutions should be freshly prepared; prolonged storage leads to degradation. The compound is validated in hepatocyte, HeLa, and stem cell models, with outcomes measured by Western blot (phospho-ACC, phospho-Smad1/5/8), qPCR (hepcidin), and phenotypic assays (dorsalization, neural induction). Careful titration is required to avoid non-specific effects at higher concentrations.

Conclusion & Outlook

Dorsomorphin (Compound C) is a rigorously benchmarked ATP-competitive AMPK inhibitor and BMP/Smad pathway modulator. Its dual mechanism enables precision in dissecting metabolic, autophagic, and differentiation processes. When used within defined concentration ranges and model systems, dorsomorphin delivers reproducible results for pathway analysis and translational research. Future work should focus on optimizing derivatives to enhance selectivity and bioavailability for in vivo applications. For further details and ordering, visit the APExBIO Dorsomorphin (Compound C) product page.