The Notch/snRNA negative feedback regulation and its implications in Alzheimer's disease
Alzheimers disease (AD) is a multifactorial disorder whose hallmark lesions have been recognized for more than a century, yet its molecular pathobiology remains fragmentary. During our AD research, we discovered a direct mechanistic axis that links the Notch signalling pathway -- a crucial regulator of cell differentiation and proliferation--with the small nuclear RNAs (snRNAs) that drive pre-mRNA splicing. For the first time, our discovery unifies two previously siloed paradigms -- cell signal transduction and RNA splicing, expanding the fundamental knowledge of gene expression and its regulation. The first contribution of the present study is the discovery and validation of the Notch/snRNA negative feedback regulation. More implications include: (1) it reframes splicing-related diseases as dynamic consequences of pathway dysregulation rather than static snRNA-gene mutations; (2) it explains why global splicing abnormalities appear in AD, aging, and cancer even when snRNA genes themselves are not mutated; and (3) it provides an immediate, druggable "splicing rheostat" for any Notch-hyperactive disorder, such as AD.