Nicotinamide mononucleotide ameliorates hypertriglyceridemia pancreatitis via NAD+/SIRT1-mediated TXNIP suppression and NOTCH pathway for accelerated repair-associated processes.

Objective: Acute pancreatitis (AP) is a life-threatening condition, and hypertriglyceridemia (HTG) is recognized as a factor exacerbating AP and impeding pancreatic regeneration. Nicotinamide mononucleotide (NMN), a precursor in the biosynthesis of nicotinamide adenine dinucleotide (NAD+), is extensively utilized to restore NAD+ levels. However, the impact of NMN on HTG-AP has not been previously addressed, which prompted our investigation into its effects and underlying mechanisms in this study.

Results: Here, through bioinformatics analysis and in vivo experiments, we identified abnormalities in the thioredoxin system. In vitro studies revealed that NMN rescued oleic acid (OA)- and palmitic acid (PA)-induced mitochondrial dysfunction and cellular injury in pancreatic acinar cells by suppressing thioredoxin-interacting protein (TXNIP) through NAD+/sirtuin 1 (SIRT1) signaling. Repeated administration of NMN significantly ameliorated P407 and caerulein (CER)-induced pancreatic injury and dysfunction in mice. Consistently, NMN exhibited the potential to reduce inflammatory responses, lower serum lipid levels, and mitigate the accumulation of reactive oxygen species (ROS). More importantly, sustained NMN treatment inhibited the NOTCH pathway and promoted M2-type macrophage dominance during the pancreatic repair phase, influencing early or late macrophage polarization, which significantly enhanced inflammation resolution. As expected, in vitro models using mouse bone marrow-derived macrophage (BMDM), RAW 264.7, and THP-1 cells confirmed that NMN influences macrophage phenotype through the NOTCH pathway.

Conclusions: Therefore, NMN ameliorates pancreatic acinar cell injury via NAD+/SIRT1-mediated TXNIP suppression and may influence macrophage polarization by inhibiting NOTCH activation, offering a novel therapeutic strategy for the treatment and repair of HTG-AP.