Investigating cognitive impairments and hippocampal proteome alterations in aged male rats with TAA-Induced minimal hepatic encephalopathy

Abstract

The aging population faces a gradual decline in physical and mental capacities, with an increased risk of liver cirrhosis and chronic liver diseases leading to hepatic encephalopathy (HE). The intertwining of physiological manifestations of aging with the pathophysiology of HE significantly impairs cognitive ability, reduces quality of life, and increases mortality. Hence, effective therapeutic intervention is imperative. The present study investigated the impact of minimal HE (MHE) on cognitive impairment in an aged rat population by analyzing hippocampal proteome dynamics. For this purpose, an old MHE rat model was induced via thioacetamide. The label-free LC‒MS/MS method was employed to explore hippocampal proteomic changes and associated dysregulated biological pathways. A total of 1533 proteins were identified, and among these, 30 proteins were significantly differentially expressed (18 upregulated, and 12 downregulated). Three upregulated proteins, namely, fetuin-A, p23, and intersectin-1 were selected and validated for their increased expression via western blotting and immunofluorescence analysis, which confirmed the mass spectrometry results. These proteins have not been reported previously in MHE cases. We also identified the possible dysregulated biological pathways associated with the differentially expressed proteins via Metascape, a network analysis tool. We found that the differentially expressed proteins may be involved in the generation of precursor metabolites and energy, the neurotransmitter release cycle, positive regulation of dendritic spine development, chaperone-mediated protein folding and protein stabilization. This study highlights the potential mechanisms underlying neurological dysfunction in the aged population with MHE and identifies novel therapeutic targets for improved disease management.

Keywords: Aging; Fetuin-A; Hippocampus; Intersectin-1; Mass spectrometry; Minimal hepatic encephalopathy; P23.