GSK3-beta (lithium, nanoparticle delivery)

Class

Nanoparticle-delivered lithium (GSK3-beta modulation)

GSK3-beta (glycogen synthase kinase 3 beta) is a constitutively active serine/threonine kinase that regulates numerous intracellular pathways, including Wnt signaling, glycogen metabolism, and phosphorylation of the microtubule-associated protein tau. It sits downstream of several growth factor and neurotrophic signaling cascades and functions largely as a negative regulator, dampening pathways involved in cell survival, synaptic plasticity, and neuronal structural integrity. Inhibiting GSK3-beta reduces phosphorylation of substrates such as tau and beta-catenin, favoring neuroprotective and pro-survival signaling. Lithium ion is one of the oldest known pharmacological inhibitors of GSK3-beta, acting both directly on the enzyme and indirectly through effects on inositol signaling. This mechanism has made GSK3-beta modulation of longstanding interest in mood disorders and, more recently, in neurodegenerative conditions such as Alzheimer's disease, where excessive tau phosphorylation contributes to neurofibrillary tangle formation. A key pharmacological challenge with lithium is its narrow therapeutic window and systemic toxicity, particularly to the kidneys and thyroid, at doses required for adequate central nervous system exposure. Nanoparticle-based delivery systems are explored as a strategy to alter the distribution of lithium in the body, aiming to achieve central nervous system exposure while limiting the peripheral tissue concentrations responsible for classical lithium toxicity.