Fig. 5: TRKC is required for the neurotrophic effects of NT-3.

a Representative βIII-tubulin immunofluorescent images of sympathetic ganglia neurons isolated from WT and TRKC + /− mice (left panel, from three independent treatments/group, scale bar = 100 µm) and quantitation of the number of neurites per neuron, total neurite length per neuron, maximal neurite length per neuron, and average neurite length per neurite per neuron (right panel, control n = 158, TRKC + /− n = 162, * indicates statistical significance between WT and TRKC + /− with unpaired two-tailed t test). b Representative βIII-tubulin immunofluorescent images of sympathetic ganglia neurons isolated from fl/fl and STRKCKO mice treated with phosphate-buffered saline (PBS) or NT-3 (100 ng/ml) (left panel, from three independent treatments/group, scale bar = 100 µm) and quantitation of total neurite length per neuron (right panel, fl/fl n = 135, fl/fl + NT-3 n = 49, STRKCKO n = 168, STRKCKO + NT-3 n = 42. Statistical significance was analyzed with two-way ANOVA. fl/fl vs STRKCKO F (1, 390) = 13.25 P = 0.0003; PBS vs NT-3 F (1, 390) = 7.680 P = 0.0059. * Indicates statistical significance with Turkey’s multiple comparisons test). Neurons from sympathetic ganglia at thoracic T1–T4 levels from 6- to 8-week-old mice were isolated and used in these experiments. c, d Representative images of TH-positive sympathetic nerve innervation in eWAT (c, left panel, from three replicate animals/group, scale bar = 2000 µm) and iWAT (d, left panel, from four replicate animals/group, scale bar = 2000 µm) and quantitation of mean nerve fiber length and mean nerve fiber branching points normalized to total adipose tissue area in eWAT (c, right panel, n = 3/group, * indicates statistical significance between WT and TRKC + /− with unpaired two-tailed t test) and iWAT (d, right panel, n = 4/group, * indicates statistical significance between WT and TRKC + /− with unpaired two-tailed t test) in TRKC + /− mice and their littermate control mice after a 7-day cold challenge. e, f Representative images of TH-positive sympathetic nerve innervation in eWAT (e, left panel, from three replicate animals/group, scale bar = 2000 µm) and iWAT (f, left panel, from four replicate animals/group, scale bar = 2000 µm) and quantitation of mean nerve fiber length and mean nerve fiber branching points normalized to total adipose tissue area in eWAT (e, right panel, n = 3/group, * indicates statistical significance between fl/fl and STRKCKO with unpaired two-tailed t test) and iWAT (f, right panel, n = 4/group, * indicates statistical significance between fl/fl and STRKCKO with unpaired two-tailed t test) in fl/fl and STRKCKO mice after a 7-day cold challenge. All data are expressed as mean ± SEM.