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. 2021 Oct 11;13(11):e13659. doi: 10.15252/emmm.202013659

Figure 4. Increased expression of 3‐microRNA signature perturbs synaptic organization and neuronal activity.

Figure 4

  1. Primary hippocampal neurons were treated with a mixture of 3‐miR mimic or control oligonucleotides, and follow‐up analyses (imaging, electrical recordings) were performed.
  2. Functional mature synapses were quantified via co‐localizations of pre‐ (synaptophysin 1) and the postsynaptic (PSD‐95) markers and compared between 3‐miR‐mix and control groups. Scale bar: 10 μm. Two independent methods (SynQuant and Colocalization) were used for quantification. 3‐miR‐mix reduced the number of functional synapses compared with controls (n = 24–30 images)
  3. Dendrite labeling and quantification. Dendritic spines were stained with Dil. Scale bar: 10 μm. Spine density and total spine length are substantially reduced in 3‐miR‐mix‐treated primary neurons compared to those treated with scrambled RNA (n = 49–97 images)
  4. Hippocampal neurons were cultured in a multielectrode array (MEA) plate equipped with sixteen electrodes. Spontaneous activity of the neurons was recorded at every 3 h (10 min/session) for 24 h. Weighted mean firing rate, number of bursts, and network bursts are significantly decreased in neurons treated with 3‐miR‐mix compared with control.
  5. The aberrant neuronal firing activity (weighted mean firing rate) and reduced number of bursts and network bursts were observed across the 24 h of time period.

Data information: For panels B, C, D, E, following statistical test has been applied: Unpaired t‐tests, two‐tailed. Bars and error bars in these plots indicate mean ± SEM. *P < 0.05, ****P < 0.0001