Figure 5.

Compromised Mitochondrial Ca²⁺ Uptake and Abnormal Cytosolic Activity in Mfn2^cKO Astrocytic Endfeet

(A) Experimental design.

(B) MitoGCaMP6-expressing astrocyte following AstroSparks processing and ROI detection. Inset displays cytosolic mCherry. Scale bar, 10 μm. Right panels: individual ROI traces and corresponding raster plot.

(C and D) Quantification of mitochondrial Ca²⁺ transient parameters, including active fraction, frequency, duration, and amplitude, in Mfn2^WT astrocytes (n = 41–53 cells from 3 mice).

(E) Example of an Mfn2^cKO astrocyte. Scale bar, 10 μm.

(F) Quantification of active mitochondria in Mfn2^WT (n = 40–56 cells, 3 mice/condition) and Mfn2^cKO (n = 36–73 cells, 2–3 mice/condition) astrocytic endfeet.

(G) Ca²⁺ transient parameters of the astrocytes in (F).

(H) Mitochondrial and cytosolic Ca²⁺ traces.

(I) Experimental in vivo setting.

(J) Example of GCaMP3-expressing astrocyte following AstroSparks processing. Scale bar, 20 μm.

(K) ROI traces and corresponding raster plots of Mfn2^WT and Mfn2^cKO astrocytes.

(L and M) Average frequency (endfeet) (L) and area of Ca²⁺ transients (M) in Mfn2^WT (n = 35–111 cells, 2–3 mice/condition) and Mfn2^cKO astrocytes (n = 51–73 cells, 2–3 mice/condition). ^∗p < 0.05, ^∗∗p < 0.01, ^∗∗∗p < 0.001 (nonparametric Mann-Whitney t test).

See also Figure S5.