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Fig. 2 | Cell Communication and Signaling

Fig. 2

From: Overexpression of miR-1 in the heart attenuates hippocampal synaptic vesicle exocytosis by the posttranscriptional regulation of SNAP-25 through the transportation of exosomes

Fig. 2

Abnormal synaptic vesicle distribution and related protein expression in the hippocampi of cardiac-specific miR-1 overexpression Tg mice. a-b Elevation of miR-1 levels in the hearts (a) and hippocampi (b) of Tg mice compared with WT mice by in situ hybridization (ISH) using DIG-lablled mmu-miR-1 probes and scramble-miR-1 (mis-miR-1) probes. The positive signal for mmu-miR-1 probes was stained in blue. c Representative electron micrographs of Tg mice. d Morphometric analysis of the total number of SVs in the synapses of neurons from the hippocampi of Tg and WT mice. PLevene < 0.0001, Kruskal-Wallis rank sum test: P < 0.0001. n = 20 synapses from 3 mice for each group. e Quantitative analysis of the distribution of SVs in WT and Tg nerve terminals. 0 nm shell: PLevene = 0.828, Student’s t test: t = − 0.473, P = 0.639; 50 nm shell: PLevene = 0.017, Kruskal-Wallis rank sum test: P = 0.001; 100 nm shell: PLevene = 0.008, Kruskal-Wallis rank sum test: P < 0.0001. n = 20 synapses from 3 mice for each group. f Active zone length was not different between WT and Tg mice. PLevene = 0.016, Kruskal-Wallis rank sum test: P = 0.844. n = 20 active zones from 3 mice for each group. g Schematic diagram of synaptic vesicle fusion. Under the stimulation of Ca2+, Munc-18 switches and binds to syntaxin-1 and assembles SNARE proteins into SNARE-complexes that promote SV fusion with presynaptic membranes. Synaptobrevin 2: VAMP-2. h Representative immunoblotting images of VAMP-2, SNAP-25, Syntaxin-1A, Munc-18. i Statistical analysis of VAMP-2: PLevene = 0.478, Student’s t test: t = − 0.200, P = 0.845; SNAP-25: PLevene = 0.562, Student’s t test: t = 3.463, P = 0.006; Syntaxin-1A: PLevene = 0.670, Student’s t-test: t = 5.067, P < 0.0001. n = 6; Munc-18: PLevene = 0.706, Student’s t-test: t = − 0.656, P = 0.527. n = 6. *P < 0.05; SV: synaptic vesicle

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