Fig. 6: Forced Mitochondria-ER tethering rescues post-ischemic impairments in arteriolar myogenic spontaneous vasomotion and capillary perfusion.

a Scheme of timepoints for MCAO surgery, 2PLSM and experimental design. b Representative still-frame images and kymographs of arterioles before and after (Occ.2hRep.22 h) ischemic stroke in SMACreER:ME-Linker mice. c Representative arteriolar radius time series curves before (dash line) and after (solid line) (Occ.2hRep.22 h) ischemic stroke in SMACreER:ME-Linker mice. d Fourier transform analysis of the rhythmic fluctuations in the arterioles before and after (Occ.2hRep.22 h) ischemic stroke in SMACreER:ME-Linker mice (N = 4 mice). The red arrow indicates the frequency peak around 0.1 Hz. e Statistical analysis of accumulated power (AUC, area under the curve) of vasomotion within the frequency range of 0–0.3 Hz before and after (Occ.2hRep.22 h) ischemic stroke in SMACreER:ME-Linker mice (N = 4 mice). f Pie chart representing the percentage of ‘inert arterioles’ before and after (Occ.2hRep.22 h) occlusion in a paired measurement in SMACreER:ME-Linker mice (N = 4 mice), which oscillates with a frequency less than venular vasomotion (0.026 Hz). Statistical analysis of the vasomotion index change rate before and after (Occ.2hRep.22 h) ischemic stroke in control littermates (blue) (N = 7 mice, n = 27 vessels) and SMACreER:ME-Linker mice (red) (N = 5 mice, n = 35 vessels), including vasomotion frequency (g), vasomotion peak interval SD (h), and vasomotion amplitude (i). j Cooperation index analysis represents the relationship of the Pearson correlation coefficient of the vascular radius changes along arterioles (2.5 μm interval between each adjacent checkpoint) in before and after (Occ.2hRep.22 h) ischemic stroke conditions (6–8 arterioles or 104–177 arteriolar segments from 4 mice). The representative image of the middle cerebral artery (from SMACreER:Ai47 mouse) below the curve helps to depict the spatial structure of arteriolar SMCs. The magenta dash line indicates correlation coefficient is 0.3. k, Representative matrixplot of cooperation index of the same arterioles before and after (Occ.2hRep.22 h) ischemic stroke, in littermate control and SMACreER:ME-Linker mouse. The magenta dash line indicates correlation coefficient is 0.3. l Representative frame-scan images of RhoB-labeled capillary blood flow before and after (Occ.2hRep.22 h) ischemic stroke in control littermates and SMAcreER:ME-Linker mice. The turquoise dots represent the spatial position of the RBC. m Kymographs of RhoB-labeled capillary blood flow before and after (Occ.2hRep.22 h) ischemic stroke in control littermates and SMAcreER:ME-Linker mice. The shaded streaks indicate the RBC motion trajectory, and the red streaks indicate the tracer-filled capillary lumen. The turquoise arrow indicates the flow direction. The capillary blood velocity (n) and blood flow (o) analysis before and after (Occ.2hRep.22 h) ischemic stroke, based on the slope and the cell number counting of the kymograph data in control littermates and SMAcreER:ME-Linker mice (N = 4 mice, n = 26 or 28 vessels). p Capillary stall rate analysis during MCAO induced ischemic stroke in control littermates and SMAcreER:ME-Linker mice. Statistics were calculated as the percentage of stalled capillaries (no blood cell flowing longer than 10.84 seconds/10 fames) among all capillaries under one imaged view (0.259 mm²) (N = 4 mice, n = 12 views). Data are expressed as the mean ± SEM. For comparisons of data between two groups, unpaired t tests were used.