Fig. 4

Buffering of neuronal nuclear calcium enhances subacute microgliosis and synapse loss 24 h post-trauma. A–C At 24 h after injury, neuronal nuclear Calcium buffering drives the significant increase of IBA1 + , IBA1 + /TMEM119 + , IBA1 + /CD11c + , IBA1 + /CST7 + and IBA1 + /CD169 + compared to TBI in mice injected with control AAV (B CT vs PT; for IBA1 + cells 7.92 ± 2.44 vs 15.74 ± 2.24; for IBA1 + /TMEM119 + cells 7.89 ± 2.40 vs 15.57 ± 2.30; for IBA1 + /CD11c + cells 7.88 ± 2.41 vs 14.50 ± 2.40; CT vs PT for IBA1 + /CST7 + cells; 2.44 ± 1.06 vs 8.79 ± 4.64; CT vs PT for IBA1 + /CD169 + cells; 3.48 ± 0.52 vs 7.95 ± 1.89). Buffering of nuclear calcium signaling in TBI did not alter the fraction of IBA1 + /CD11c + cells (C: CT vs PT; 97.06 ± 4.48% vs 91.80 ± 2.72%), but increased the fraction of CST7 + and CD169 +  + (CT vs PT for CST7; 29.72 ± 5.31% vs 63.82 ± 18.50%; CT vs PT vor CD169; 47.13 ± 17.14% vs 61.36 ± 7.11%). Data are shown as mean ± SD. N = 4. Scale bar 100 µm (overview) and 20 µm (insert). D–E TBI decreases excitatory (Shank2/3+) synaptic density in the core (CS vs CT; 843.10 ± 84.62 vs 545.32 ± 138.21) but not in the perilesional area of the injury. Buffering of nuclear calcium signaling did not worsen the core synaptic density upon TBI but significantly decreased synaptic density in the perilesional area (CT vs PT; 769.9 ± 152.8 vs 471.3 ± 80.9). N = 4. F Significant decrease in neuronal density in the injury core 24 h post-TBI (CS vs CT; 33.82 ± 3.32 vs 18.50 ± 3.44). Buffering nuclear calcium signaling did not worsen neuronal density in the core compared to TBI alone (CT vs PT; 18.50 ± 3.44 vs 20.09 ± 3.41). Significant decrease in neuronal density in the perilesional area post-TBI to sham and nuclear calcium buffering (CS vs CT; 34.2 ± 1.55 vs 22.25 ± 4.67; CT vs PT; 22.25 ± 4.67 vs 29.88 ± 4.52). Data are shown as mean ± SD. N = 4. Scale bar 100 µm (overview) and 5 µm (insert). *p < 0.05; **p < 0.01; ***p < 0.001; ****p < 0.0001