Quantitative Analysis of Dendritic Spine Alterations in Alzheimer’s Disease Using Neurolucida 360
Walker CK, Greathouse KM, Tuscher JJ, Dammer EB, Weber AJ, Liu E, Curtis KA, Boros BD, Freeman CD, Seo JV, Ramdas R, Hurst C, Duong DM, Gearing M, Murchison CF, Day JJ, Seyfried NT, Herskowitz JH. Cross-platform synaptic network analysis of human entorhinal cortex identifies twf2 as a modulator of dendritic spine length. J Neurosci 2023;43(20):3764-3785. doi: 10.1523/JNEUROSCI.2102-22.2023.
Background: Synaptic dysfunction and dendritic spine alterations are early and critical events in Alzheimer’s disease (AD), particularly within the entorhinal cortex, which plays a key role in memory processing. Proteomic studies have identified numerous molecular changes in AD, but linking these to specific cellular phenotypes remains a challenge.
Hypothesis: This study hypothesized that integrating synaptic proteomic data with dendritic spine morphology metrics enables identification of proteins that regulate dendritic spine structure in the human entorhinal cortex.
Methods: The authors analyzed post mortem entorhinal cortex tissue from control, cognitively resilient and AD individuals. Dendritic spines on pyramidal neurons were imaged after Golgi–Cox staining and reconstructed using Neurolucida 360, with quantitative analyses performed in Neurolucida Explorer. Parallel proteomic profiling of synaptosomal fractions was performed using mass spectrometry and weighted co-expression network analysis, followed by CRISPR activation experiments in cultured neurons.
Results: AD samples exhibited reduced overall dendritic spine density compared with controls, while cognitively resilient cases maintained densities similar to controls. Co-expression analysis identified a protein module correlated with thin spine length, with Twinfilin-2 (TWF2) as its central hub. Increasing TWF2 expression in neurons selectively lengthened thin spines without altering density.
Conclusions: These findings identify TWF2 as a modulator of dendritic spine length and validate an integrated proteomic–morphometric approach to discover synaptic regulators in AD.
