Fig. 8: Interfering with DOCK4 enhances heat nociception in nonhuman primates and knockdown DOCK4 increases Nav1.7 currents in human DRG neurons.

a High-resolution images show the colocalization of Dynein, DOCK4, and Nav1.7 in DRG neurons of a monkey. Scale bar, 10 μm. b–d Heat sensitivity changes in monkeys after intrathecal injection of DOCK4-siRNA (20 nmol) in tail-flick and hot plate tests. n = 4 monkeys per group. F_{(1, 24)} = 21.87, P = 0.0000001 in (b); F_{(1, 24)} = 2.807, P = 0.0068 in (c); F_{(1, 24)} = 1.607, P = 0.0134 in (d). e Immunocytochemistry showing knockdown of DOCK4 expression by DOCK4-siRNA treatment (50 nM, 48 h) in cultured monkey DRG neurons. Scale bar, 100 μm. f Intensity of DOCK4-immunoreactivity in monkey DRG neurons after DOCK4-siRNA and nontargeting (NT)-siRNA treatment. n = 33 neurons in NT-siRNA, n = 32 neurons in DOCK4-siRNA. t₆₃ = 6.622, P = 0.000000009. g The influence of DOCK4 knockdown on the distribution of Nav1.7 in the membrane and cytoplasm of cultured monkey DRG neurons. Profile plots were utilized to delineate membrane staining. Scale bar, 25 μm. h The impact of DOCK4 knockdown on the peak Nav1.7 currents in cultured monkey DRG neurons. n = 8 neurons in NT-siRNA, n = 9 neurons in DOCK4-siRNA. F_{(1, 555)} = 116.4, P = 9.19×10⁻²⁵. i The expression of DOCK4 protein in human DRG sections. Scale bar, left: 500 μm, right: 200 μm. j The size frequency distribution of DOCK4-positive (DOCK4⁺) and total neurons was examined in human DRG sections. A total of 2706 neurons from three human DRGs were analyzed. k The co-localization of Dynein, DOCK4, and Nav1.7 in human DRG neurons. Scale bar, 100 μm. l High-resolution images show the colocalization of Dynein, DOCK4, and Nav1.7 in DRG neurons of human. Scale bar, 1 μm. m Proximity ligation assay (PLA) shows positive signals of DOCK4/Nav1.7 interaction in cultured human DRG neurons (5 images from two repeats). Scale bar, 100 μm. n Proximity ligation assay (PLA) shows positive signals of DOCK4/Dynein interaction in cultured human DRG neurons (6 images from two repeats). Scale bar, 100 μm. o Proximity ligation assay (PLA) shows positive signals of Dynein/Nav1.7 interaction in cultured human DRG neurons with NT-siRNA treatment, and signals was loss in cultured human DRG neurons with DOCK4-siRNA treatment (6 images from two repeats). Scale bar, 100 μm. p The influence of DOCK4 knockdown on the distribution of Nav1.7 in the membrane and cytoplasm of cultured human DRG neurons. Profile plots were utilized to delineate membrane staining. Scale bar, 25 μm. q The impact of DOCK4 knockdown on the peak Nav1.7 currents in cultured human DRG neurons. n = 9 neurons in NT-siRNA, n = 8 neurons in DOCK4-siRNA. F_{(1, 620)} = 69.65, P = 4.61 × 10⁻¹⁶. r The model shows that DOCK4 acts as an adaptor, helping assemble the Nav1.7/DOCK4/Dynein complex to traffic Nav1.7 from the membrane to the cytoplasm in DRG neurons, affecting thermal pain perception. Loss of DOCK4 disrupts this process, increasing Nav1.7 membrane expression and causing heat hyperalgesia. f, Two-tailed Independent Student’s t test; b–d, h, q, Two-way ANOVA followed by Bonferroni’s multiple comparisons test. ^*P < 0.05, ^**P < 0.01, ^***P < 0.001, n.s. means not significant. Data are presented as mean ± SEM. Complete sample size and sex is provided in the Supplementary Data. Source data are provided as a Source Data file.