Fig. 3

Overexpression of circRIMS2 induces memory and synaptic impairments in vivo. a Fluorescence images of a hippocampal slice infected with circRIMS2 lentivirus. Green represents circRIMS2 and blue represents DAPI-stained nuclei. Enlarged CA3 area is shown in the lower panel. Scale bar, 200 μm (upper) and 100 μm (lower). b, c MWM was conducted one month after injecting circRIMS2 or control (Vector) lentivirus into the hippocampus of 4-month-old C57BL/6 mice. Representative traces and latencies during the learning stage are shown (b) and crossing times (c) on day 7 were analyzed (n = 15, 10 for vector and circRIMS2, respectively). d Representative Golgi-cox staining images show dendritic spines of C57BL/6 mice after injection with circRIMS2 or vector lentivirus. Scale bar, 5 μm. e, f Changes of spine density (e) and percentage of mushroom spines (f) were assessed (n = 20). g Golgi-cox staining images show dendritic trees in circRIMS2- or vector-injected mice. Scale bar, 25 μm. h, i The dendritic complexity of circRIMS2- or vector-injected mice was examined using Sholl (h) and dendritic complexity index (DCI, i) (n = 5). j Protein levels of GluN2B, GluN2A, GLUR1, and GLUR2 were measured in vector- or circRIMS2-injected mice. Representative blots (left) and quantitative analysis (right) are presented (n = 5). k qRT-PCR analysis of circRIMS2 and miR-3968 levels in these mice (n = 4). Data are presented as mean ± SEM and two-tailed t tests were used unless otherwise specified. *P < 0.05, **P < 0.01, ***P < 0.001