Does IL-6 trigger the liver’s acute-phase response to raise ferritin and lower albumin during inflammation?

Systemic inflammation initiates a profound metabolic and synthetic shift in the liver known as the acute-phase response. Interleukin-6 (IL-6) serves as the primary cytokine orchestrating this hepatic redirection to prioritize host defense.

Molecular mechanisms in hepatocytes

• JAK/STAT3 pathway activation: IL-6 binds to its receptor and the gp130 complex on hepatocytes, activating Janus kinases (JAKs) which phosphorylate and activate STAT3.
• Transcriptional redirection: Activated STAT3 drives the hepatic acute-phase program, coordinating the transcriptional upregulation of positive acute-phase genes and the concurrent suppression of negative acute-phase reactants.

Ferritin upregulation and albumin suppression

• Ferritin synthesis: IL-6 signaling upregulates both light- and heavy-chain ferritin mRNA and protein expression. This process typically yields a 1.3- to 1.5-fold increase in transcription, promoting intracellular iron sequestration to limit pathogen access to iron.
• Albumin downregulation: Conversely, IL-6 suppresses albumin synthesis in a dose- and time-dependent manner. This suppression occurs at the transcriptional level as STAT3 activation alters the promoter occupancy of liver-enriched transcription factors, such as HNF1 and HNF3, and recruits inhibitory nuclear complexes to reduce albumin gene expression.

Bottom line

• IL-6 acts as the master regulator of the hepatic acute-phase response, utilizing JAK/STAT3 signaling to transcriptionally upregulate protective proteins like ferritin while actively suppressing albumin synthesis to reprioritize cellular resources during inflammatory stress.