Fig. 5
From: The pathogenic role of c-Kit+ mast cells in the spinal motor neuron-vascular niche in ALS
Mast cells are associated with altered microvascular elements in ALS patients and mice. A Representative confocal microphotographs of c-Kit+ (red)/chymase+ (green) mast cells (magenta arrows) associated with microvascular elements stained with Collagen-I (white) in the surroundings of degenerating motor neurons (white dotted lines) in the lumbar spinal cord of autopsy ALS subjects and control donors. Both small non-granular and degranulating mast cells are observed in the ALS spinal cords (left and middle panel), as compared with few small rounded cells present in the spinal cord of control donors (right panel). B High magnification confocal analysis of c-Kit+/chymase+ mast cells associated with pathological blood vessels. Note that granular mast cells seem to emerge from a blood vessel stained with collagen-I into the parenchyma of the spinal cord. High magnification analysis (magenta square) is shown in the right upper panel where the boundaries of the blood vessel were depicted only as a white solid line. The close contact between damaged blood vessels and mast cells is indicated by the magenta arrow. The three panels below show orthogonal views of the z stack, to illustrate the damage observed in the blood vessels in contact with mast cells (magenta arrows). C Representative confocal analysis of pathological features of microvasculature in the ALS lumbar spinal cord. Frequent morphological abnormalities as observed by collagen-I interruptions (yellow arrow ALS #1), strings (yellow asterisks ALS #2), and sprouts (yellow arrowheads ALS #4). Alterations in the microvasculature are not observed in control donors (control #2). D Representative confocal characterization of abnormal microvascular elements stained with collagen-I (white) in the spinal cord of symptomatic SOD1G93A mice but not in Non-Tg littermates (upper panels). Lower panels show the association of c-Kit+ mast cells with the motor neuron-vascular niche. βIII-Tubulin antibody was used to stain motor neurons (orange) and collagen-I to stain blood vessels (white). The magenta squares show a 3D high magnification analysis of the niche and c-Kit+ mast cells (red—magenta arrows) respectively. The graph to the right shows the quantitative analysis of the number of string vessels and vessel sprouts in SOD1G93A symptomatic compared to Non-Tg littermates. Data are expressed as mean ± s.e.m. For statistical analysis two-tailed Mann–Whitney test was used, with ***p < 0.0001 considered significant. n = 4 animals/condition. Scale bars: 20 μm in (Aand C), 10 μm in (D), and 5 μm in (B)