Hui Lu

Cognitive impairment is a major public health concern, and the liver–brain axis has attracted growing interest. Gamma-glutamyl transferase (GGT) is a serum marker of liver function, but its association with cognitive outcomes remains uncertain. We conducted a cross-species analysis. In 5xFAD mice (n = 52), we examined serum liver markers and spatial cognition using the Morris water maze. In NHANES 2011–2014 (n = 3181, aged ≥60 years), we evaluated liver markers and low cognitive performance (LCP) using multivariable logistic regression. We also performed virtual hepatic GGT1 knockout in a human liver single-cell atlas and integrated GTEx liver co-expression, transcription factor enrichment, and WGCNA analyses. In mice, GGT–cognition associations largely attenuated after strain adjustment, but a positive association with platform crossings emerged (r = 0.321, p = 0.02). In NHANES, serum GGT was inversely associated with LCP (Q4 vs. Q1 OR = 0.54, p < 0.001), with a nonlinear association and an inflection point near 19 U/L. Virtual hepatic GGT1 knockout identified eight immunoglobulin-related genes associated with SPI1 and oxidative stress-related pathways. These parallel findings are hypothesis-generating. A testable hypothesis is that lower hepatic GGT1 activity or serum GGT is associated with upregulated cholangiocyte immunoglobulin-related programs and poorer cognition.

Background/Objectives: Alzheimer’s disease (AD) is characterized by amyloid-beta accumulation and neuroinflammation, yet the molecular target of Ginsenoside Rg1 remains elusive. This study aimed to elucidate the neuroprotective mechanism of Ginsenoside Rg1, specifically investigating its interaction with C-C motif chemokine receptor 3 (CCR3). Methods: We utilized 5xFAD transgenic mice and CCR3-overexpressing BV2 microglial cells. Behavioral assessments, enzyme-linked immunosorbent assays, quantitative real-time polymerase chain reaction, molecular docking, and surface plasmon resonance were employed to evaluate cognitive function and molecular pathways. Results: Ginsenoside Rg1 treatment significantly ameliorated spatial learning and memory deficits. Quantitatively, Rg1 reduced cortical amyloid-beta 1–40 levels (p < 0.05) and bound directly to CCR3 with a dissociation constant of 3.599 × 10⁻⁵ mol/L. This inhibition suppressed neuroinflammation and restored neurotrophic factors, including Brain-derived neurotrophic factor. Conclusions: CCR3 is a novel pharmacological target for Ginsenoside Rg1, providing a precise molecular basis for its neuroprotective effects. Future research should focus on clarifying the pharmacokinetic profile and brain bioavailability of Ginsenoside Rg1 to facilitate clinical translation.