VD/VDR-mediated ATG16L1 activation reduces Alzheimer’s disease-like pathology and cognitive decline

Despite extensive global efforts, there is currently no effective remedy for Alzheimer’s disease (AD). This investigation aimed to examine the impact of vitamin D/vitamin D receptor (VDR)/ATG16L1 signaling on memory in AD mice, as well as the levels of autophagy and inflammation in the hippocampus. Administering cholecalciferol cholesterol emulsion (CCE), which serves as a precursor to 1,25-OH vitamin D3, through water feeding for a duration of 12 weeks demonstrated the ability to mitigate both short-term and long-term memory impairments in AD mice. CCE treatment reduced the deposition of TAU protein in the hippocampus, suppressed the phosphorylation of TAU Thr181 and 212, and significantly decreased Aβ (1–40) levels. Moreover, CCE heightened hippocampal autophagy in AD mice, upregulated the expression of ATG16L1 and LC3B, and inhibited P62 expression. In addition, CCE supplementation attenuated hippocampal inflammation in AD mice by decreasing the levels of IL1β and TNFα and restoring the TOM1/IL1R1 pathway. The Luciferase reporter assay verified that the knockdown of VDR could impede the activation of the ATG16L1 promoter by vitamin D, and ChIP analysis confirmed that VDR could bind to the ATG16L1 promoter and exert its function. CCE exhibits potential in safeguarding hippocampal neurons against AD-induced harm, stimulating autophagy, and suppressing inflammation. These effects may be regulated by VD/VDR/ATG16L1 signaling.