Figure 1

Co-culture with human umbilical cord blood-derived-mesenchymal stem cells (hUCB-MSCs) prevents reduction in synaptic density in Aβ42 peptide-treated primary hippocampal neurons. (A) Contamination by non-neuronal cells was removed with cytosine arabinoside (AraC) treatment of the primary hippocampal cell culture, and differentiated cells were confirmed to be mostly hippocampal neurons by staining for microtubule-associated protein 2 (MAP2), a neuron-specific marker (Scale bar = 200 μm). (B) Aβ42 peptide-induced cytotoxicity was measured in primary hippocampal neurons at 72 h after treatment in a dose-dependent manner. Treatment with 2 μM of Aβ42 peptide was verified via analysis of microscope images and TUNEL assay, confirming that this concentration did not cause cytotoxicity in hippocampal neurons (Scale bar = 100 μm, mean ± SEM, ** p < 0.005, n = 3 per group, n.s.: not significant). (C) Representative images of hippocampal neurons stained with antibodies specific for pre-synaptic (SYP, green) and post-synaptic (PSD-95, red) proteins (Scale bar = 25 μm, Neu: neuron). Bottom insets (white boxes) show higher magnification. Quantification of synaptic density (number of synapses per 100 μm of dendritic length, n ≥ 30 dendrites) revealed that co-culture with hUCB-MSCs rescued hippocampal neurons from Aβ42 peptide-induced synaptic dysfunction (mean ± SEM, **p < 0.005, n.s.: not significant). (D) hUCB-MSCs-administered mouse brains were extracted and analysed by immunoblotting for SYP and PSD-95 antibodies. β-Actin was used as a loading control. (n = 4 for CTRL: MEMα-administrated 5XFAD, n = 5 for MSC: hUCB-MSC-administered 5XFAD, *p < 0.05).