Fig. 2: Gut-brain axis and circadian rhythm association.

Aberrant activity of SIRT1, MAPK, and GSK-3 results in altered BMAL1 activity in AD. On the other hand, disruption in BMAL1 activities may contribute to altered IgA secretion and gut microbiota abundance. This process induced Aβ deposition, neuroinflammation, and BBB disruption leading to AD progression. AD Alzheimer’s disease, BMAL1 brain and muscle ARNT-Like 1, GSK-3 glycogen synthase kinase, MAPK mitogen-activated protein kinases, SIRT1 Sirtuin 1.