Tat-Beclin-1 Ameliorates Memory by Improving Neuronal Cytoarchitecture and Mitigating Mitochondrial Dysfunction in Scopolamine-Induced Amnesic Male Mice.

Abstract

Mitophagy, the targeted breakdown of damaged mitochondria, plays a vital role in maintaining cellular homeostasis. As impairment of mitophagy leads to neurodegeneration and memory decline, the current study explores the therapeutic potential of an autophagy inducer Tat-Beclin-1 during scopolamine-induced amnesia. Tat-Beclin-1 improved contextual and recognition memory and also mitochondrial ultrastructure by restoring mitochondrial length and area and reducing the number of fragmented mitochondria. Tat-Beclin-1 upregulated the expression of genes associated with mitophagy (PTEN-induced kinase 1, Parkin, Lamp2, and LC3), mitochondrial fusion (Mfn1, Mfn2, and optic atrophy1), and fission (dynamin-related protein 1 and Fis1) in amnesic mice. Subsequently, these results were supported by a decreased level of p-Drp1 (S616) and Drp 1 ratios and an increased level of Mfn2, LC3BI, and BII in Tat-Beclin-1-treated mice. Moreover, Tat-Beclin-1 maintained mitochondrial membrane potential and complex I/V activity in amnesic mice. Tat-Beclin-1 enhanced myelination and diminished the activity of acetylcholinesterase and caspase-3 activity. Sholl analysis revealed augmented dendritic branching and length, elevated dendritic spine density, and upregulated the expression of synaptophysin and PSD95 proteins, indicating neuronal plasticity enhancement by Tat-Beclin-1. Thus, these findings provide valuable insights into the therapeutic potential of Tat-Beclin-1, addressing mitochondrial dysfunction to mitigate cognitive impairment associated with amnesic conditions.