Melatonin may ameliorate colitis by regulating gut microbiota, modulating antimicrobial peptide secretion, and reinforcing intestinal epithelial barrier integrity potentially via activation of the SIRT1-LKB1-pAMPK axis.
Key Findings
Results
IBD patients had lower levels of serum melatonin and fecal 2-oxomelatonin compared to controls.
Fecal melatonin and its metabolites were detected in IBD patients as part of clinical assessment
Both serum melatonin (MT) and fecal 2-oxomelatonin (a melatonin metabolite) were found to be reduced in IBD patients
This finding links circadian rhythm disruption and sleep disturbances previously reported in IBD patients to measurable reductions in melatonin levels
Results
Melatonin treatment enhanced intestinal antimicrobial peptides and effectively alleviated colitis in a DSS-induced mouse model.
A dextran sodium sulfate (DSS)-induced colitis mouse model was used to evaluate melatonin's effects in vivo
Melatonin upregulated antimicrobial peptide expression in mouse colonic tissues
Melatonin treatment was associated with alleviation of colitis symptoms in DSS-treated mice
An LPS-stimulated NCM460 cell inflammation model was used in parallel to explore mechanisms in vitro
Results
Melatonin restored the abundance of the probiotic Akkermansia and decreased the conditional pathogen Desulfovibrio in the gut microbiome.
Gut microbiota composition was assessed in the DSS-induced colitis mouse model following melatonin treatment
Akkermansia, considered a beneficial probiotic bacterium, was increased in abundance following melatonin administration
Desulfovibrio, classified as a conditional pathogen, was decreased in abundance following melatonin administration
These microbiota shifts suggest melatonin's role in mediating gut health extends to modulation of microbial communities
Results
Melatonin upregulated SIRT1 and phosphorylated AMPK (pAMPK) expression in mouse colonic tissues.
SIRT1 (Sirtuin 1) protein expression was increased in colonic tissues of melatonin-treated DSS mice
Phosphorylated AMP-Activated Protein Kinase (pAMPK) was also upregulated in colonic tissues following melatonin treatment
These molecular changes were observed in the DSS-induced colitis mouse model
Upregulation of both proteins suggests melatonin activates an energy-sensing and deacetylase signaling cascade in inflamed intestinal tissue
Results
Pharmacological inhibition of SIRT1 or pAMPK abolished the protective effects of melatonin in DSS-treated mice.
Ex-527, a selective SIRT1 inhibitor, was used to block SIRT1 activity in DSS mice treated with melatonin
Compound C, a pAMPK inhibitor, was used to block AMPK phosphorylation in DSS mice treated with melatonin
Both inhibitors individually abolished the protective effects of melatonin in the DSS colitis model
These pharmacological experiments provide mechanistic evidence that SIRT1 and pAMPK are required for melatonin's protective actions
Results
In LPS-stimulated NCM460 cells, SIRT1 and pAMPK inhibitors blocked melatonin's regulation of proinflammatory factors, antimicrobial peptides, and tight junctions.
NCM460 cells stimulated with lipopolysaccharide (LPS) served as an in vitro intestinal epithelial inflammation model
Inhibition of SIRT1 or pAMPK reversed melatonin-induced changes in proinflammatory cytokine expression
Inhibitor treatment also blocked melatonin's upregulation of antimicrobial peptides in LPS-stimulated cells
Tight junction protein regulation by melatonin was similarly abolished by the inhibitors, implicating the SIRT1-LKB1-pAMPK axis in barrier integrity maintenance
Results
Melatonin's protective mechanisms were mechanistically associated with activation of the SIRT1-LKB1-pAMPK signaling pathway.
The SIRT1-LKB1-pAMPK axis was identified as a mechanistic pathway through which melatonin exerts its effects
LKB1 (Liver Kinase B1) serves as an intermediate kinase linking SIRT1 deacetylase activity to AMPK phosphorylation in this proposed pathway
The pathway was implicated in regulating gut microbiota composition, antimicrobial peptide secretion, and intestinal epithelial barrier integrity
Both in vivo (DSS mouse model) and in vitro (LPS-NCM460 cell model) evidence supported this mechanistic conclusion
What This Means
This research suggests that people with inflammatory bowel disease (IBD) have lower levels of melatonin — a hormone best known for regulating sleep — both in their blood and in their stool. Using mouse models of colitis and human intestinal cells grown in the lab, the researchers found that giving melatonin helped reduce gut inflammation in several ways: it boosted the production of natural antimicrobial proteins in the gut lining, increased the abundance of a beneficial gut bacterium called Akkermansia, and reduced levels of a potentially harmful bacterium called Desulfovibrio. Melatonin also appeared to strengthen the physical barrier of the intestinal lining, which is often compromised in IBD.
The researchers traced these protective effects to a specific chain of molecular signals inside intestinal cells, involving proteins called SIRT1, LKB1, and AMPK. When they used drugs to block either SIRT1 or AMPK, melatonin's beneficial effects were largely cancelled out, suggesting these proteins are essential links in how melatonin exerts its protective actions. This adds to a growing body of evidence that melatonin does more than regulate sleep — it also plays a role in gut immune defense and barrier function.
This research suggests that the sleep disturbances commonly reported by IBD patients may be connected to a broader deficiency in melatonin that also affects gut health. These findings open a potential avenue for exploring melatonin as a therapeutic approach to help repair the intestinal barrier in IBD, though the work was conducted primarily in animal and cell models, and further research in humans would be needed to confirm these effects.
Mao Q, Lin B, Xia W, Zhang Y, Lei Y, Cao Q, et al.. (2026). Melatonin-induced restoration of the intestinal mucosal barrier in inflammatory bowel disease via activation of the SIRT1-LKB1-pAMPK axis.. Frontiers in immunology. https://doi.org/10.3389/fimmu.2026.1811583