Regulation of Lipogenesis through Fungal Bioactives: Mechanisms and Metabolic Pathways
How the Cell Produces Fat — and How It Stops
— HOOK —
Throughout the day, the hepatocyte converts glucose, fructose, and acetyl-CoA released from excess protein catabolism into fatty acids. This process is not governed by a single enzyme but by a tightly coordinated transcriptional network. SREBP-1c, ChREBP, and AMPK represent the most well-characterised nodes within this regulatory architecture.
This article examines the molecular regulation of lipogenesis and the interaction of functional mushroom constituents with these pathways, as demonstrated at the in vitro and animal model levels.
Lipogenesis: A Three-Stage Assembly Line in the Liver
De novo lipogenesis (DNL) is the biosynthesis of fatty acids from glucose. It proceeds through three principal stages:
- The acetyl-CoA pool: Following glycolysis, pyruvate enters the mitochondrion and is shuttled into the cytosol as citrate.
- Malonyl-CoA production: Acetyl-CoA carboxylase (ACC) catalyses this committed step.
- Fatty acid synthesis: Fatty acid synthase (FAS) assembles palmitic acid.
The fatty acids produced are esterified into triglycerides and secreted into circulation as VLDL particles. Excessive DNL occupies a central role in the pathogenesis of hepatic steatosis (NAFLD) (Donnelly et al., 2005; PMID: 15864352).
SREBP-1c and ChREBP: Transcriptional Command
SREBP-1c is an insulin-responsive transcription factor. Under hyperinsulinaemic conditions, it undergoes proteolytic cleavage to its mature form, translocates to the nucleus, and activates lipogenic genes including ACC and FAS. ChREBP, by contrast, responds to glucose and fructose; it drives DNL particularly after high-carbohydrate intake.
The concerted action of SREBP-1c and ChREBP explains why DNL is so markedly elevated under modern dietary patterns — especially those rich in fructose (Iizuka & Horikawa, 2008; PMID: 18524333).
AMPK: The Cellular Energy Sensor and Lipogenic Brake
AMPK becomes activated when the intracellular AMP/ATP ratio rises. Active AMPK phosphorylates and inactivates ACC while simultaneously suppressing SREBP-1c synthesis. The net outcome: fatty acid production halts, and β-oxidation accelerates.
AMPK activation lies at the mechanistic core of several pharmacological agents, including metformin, as well as a range of natural compounds (Hardie, 2011; PMID: 21934090).
Mushroom Constituents and the Lipogenesis Literature
Reishi triterpenes have been reported to reduce SREBP-1c expression and enhance AMPK phosphorylation in in vitro hepatocyte models (Wang et al., 2013; PMID: 23892018). The effect is mediated not by a single compound but by the collective action of ganoderic acid derivatives.
Maitake D-fraction has demonstrated a tendency to reduce hepatic triglyceride accumulation in animal models; the effect has been linked to indirect suppression of lipogenic gene expression (Sato et al., 2009; PMID: 19584492).
Shiitake's eritadenine content is recognised for its influence on cholesterol metabolism — a mechanism distinct from DNL, yet one that exerts an integrative effect on hepatic lipid homeostasis (Sugiyama et al., 1995; PMID: 7616018).
Limitations
The studies cited are predominantly at the in vitro and animal model levels. Human clinical data remain limited and derive from heterogeneous trial designs. Findings concerning lipogenesis modulation should be regarded as investigative subjects with respect to the potential contribution of mushrooms to metabolic health.
Related Readings
- Mushrooms and Cholesterol — Eritadenine and hepatic metabolism.
- Mushrooms and Diabetes — The insulin sensitivity context.
- D-Fraction — Maitake's polysaccharide fraction.
This content is provided for informational purposes and does not constitute medical advice. Consult a physician before making any health-related decisions. Functional mushrooms are not medicines and cannot be used to treat diseases.
Version: 1.0 | Last updated: 28 April 2026 | Sources reviewed: 12+ | Method: Editorial Policy | References: Bibliography
