Figure 5

HA promotes neuronal differentiation but decreases dopaminergic neurons in cultured VM NSPC. After proliferation, cells were kept on differentiating conditions for 6 days (N2 medium without FGF-2) and treated daily with different concentrations of HA (from 1 μM to 1 mM HA). VM NSPCs were analyzed after differentiation. (A) Micrographs showing the neuronal marker β-III Tubulin in control and 10 μM HA-treated cultures. Nuclei were stained with Hoechst. (B) Quantification of β-III Tubulin labeled cells relative to the total number of cells, showing a significant increase in the proportion of β-III Tubulin + cells caused by treatment with 10 μM HA. (C) Micrographs of double immunocytochemistry to detect the neuronal marker β-tubulin III and the dopaminergic marker Tyrosine Hydroxylase (TH) in control and 1 mM HA-treated cultures. Nuclei were stained with Hoechst. Scale bar = 100 μm. (D) Graph showing the percentage of TH-positive neurons in control and after HA treatments, relative to the total number of β-Tubulin III-positive cells. TH + neurons were significantly decreased after treatment with 1 mM HA. **p < 0.01. (E) Micrographs showing the dopaminergic marker TH in control cells, and the decrease caused by 1 mM HA. The H1R antagonist chlorpheniramine was tested either with or without HA. Nuclei were stained with Hoechst. (F) HA-induced decrease of TH-positive numbers was antagonized by chlorpheniramine. Note that the percentage of TH-positive cells is lower than in Figure 4D because it is normalized by the total number of cells. *p < 0.05 relative to control; ^##p < 0.01 compared to 1 mM HA. Scale bars = 100 μm.