Astrocyte-derived lactoferrin inhibits neuronal ferroptosis by reducing iron content and GPX4 degradation in APP/PS1 transgenic mice.

Increased astrocytic lactoferrin (Lf) expression was observed in the brains of elderly individuals and Alzheimer's disease (AD) patients. Our previous study revealed that astrocytic Lf overexpression improved cognitive capacity by facilitating Lf secretion to neurons to inhibit ß-amyloid protein (Aß) production in APP/PS1 mice. Here, we further discovered that astrocytic Lf overexpression inhibited neuronal loss by decreasing iron accumulation and increasing glutathione peroxidase 4 (GPX4) expression in neurons within APP/PS1 mice. Furthermore, human Lf (hLf) treatment inhibited ammonium ferric citrate (FAC)-induced ferroptosis by chelating intracellular iron. Additionally, machine learning analysis uncovered a correlation between Lf and GPX4. hLf treatment boosted low-density lipoprotein receptor-related protein 1 (LRP1) internalization and facilitated its interaction with heat shock cognate 70 (HSC70), thereby inhibiting HSC70 binds to GPX4, and eventually attenuating GPX4 degradation and FAC-induced ferroptosis. Overall, astrocytic Lf overexpression inhibited neuronal ferroptosis through two pathways: reducing intracellular iron accumulation and promoting GPX4 expression via inhibiting chaperone-mediated autophagy (CMA)-mediated GPX4 degradation. Hence, upregulating astrocytic Lf expression is a promising strategy for combating AD.

From zinc homeostasis to disease progression: Unveiling the neurodegenerative puzzle.

Zinc is a crucial trace element in the human body, playing a role in various physiological processes such as oxidative stress, neurotransmission, protein synthesis, and DNA repair. The zinc transporters (ZnTs) family members are responsible for exporting intracellular zinc, while Zrt- and Irt-like proteins (ZIPs) are involved in importing extracellular zinc. These processes are essential for maintaining cellular zinc homeostasis. Imbalances in zinc metabolism have been linked to the development of neurodegenerative diseases. Disruptions in zinc levels can impact the survival and activity of neurons, thereby contributing to the progression of neurodegenerative diseases through mechanisms like cell apoptosis regulation, protein phase separation, ferroptosis, oxidative stress, and neuroinflammation. Therefore, conducting a systematic review of the regulatory network of zinc and investigating the relationship between zinc dysmetabolism and neurodegenerative diseases can enhance our understanding of the pathogenesis of these diseases. Additionally, it may offer new insights and approaches for the treatment of neurodegenerative diseases.

Identification of AS1842856 as a novel small-molecule GSK3α/ß inhibitor against Tauopathy by accelerating GSK3α/ß exocytosis.

Glycogen synthase kinase-3α/ß (GSK3α/ß) is a critical kinase for Tau hyperphosphorylation which contributes to neurodegeneration. Despite the termination of clinical trials for GSK3α/ß inhibitors in Alzheimer's disease (AD) treatment, there is a pressing need for novel therapeutic strategies targeting GSK3α/ß. Here, we identified the compound AS1842856 (AS), a specific forkhead box protein O1 (FOXO1) inhibitor, reduced intracellular GSK3α/ß content in a FOXO1-independent manner. Specifically, AS directly bound to GSK3α/ß, promoting its translocation to the multivesicular bodies (MVBs) and accelerating exocytosis, ultimately decreasing intracellular GSK3α/ß content. Expectedly, AS treatment effectively suppressed Tau hyperphosphorylation in cells exposed to okadaic acid or expressing the TauP301S mutant. Furthermore, AS was visualized to penetrate the blood-brain barrier (BBB) using an imaging mass microscope. Long-term treatment of AS enhanced cognitive function in P301S transgenic mice by mitigating Tau hyperphosphorylation through downregulation of GSK3α/ß expression in the brain. Altogether, AS represents a novel small-molecule GSK3α/ß inhibitor that facilitates GSK3α/ß exocytosis, holding promise as a therapeutic agent for GSK3α/ß hyperactivation-associated disorders.