Fig 2: Diagrammatic sketch for mechanism that ANXA7 regulates neuron apoptosis after spinal cord injury.ANXA7 could interact with LAMP5 through the binding site ANXA7D411 to regulate autophagy and apoptosis. Interaction between ANXA7 and LAMP5 is significantly inhibited after spinal cord injury. SEC, the activator of ANXA7, can promote the interaction between ANXA7 and LAMP5 by activating the activity of ANXA7, thereby promoting autophagy by stabilizing the acidic environment of lysosomes and regulating mTOR/TFEB signaling pathway, thus inhibiting apoptosis, repairing damaged neurons, and promoting the repair of spinal cord injury. Red arrow and symbol ‘-’: inhibiting effect; Green arrow and symbol ‘+’: promoting effect.

Fig 3: ANXA7 is significantly downregulated after neuron injury.a Neurons were treated with OGD/R, after which immunofluorescence staining was used to detect ANXA7 protein level. Scale bars: 10 µm. b Neurons were treated with OGD/R and Western blotting was used for protein detection. c Spinal cord injury model was performed in C57BL/6 mice, the distribution of ANXA7 were detected by immunohistochemistry staining in head-end, tail-end and injury center in spinal cord after 24 h of injury. Scale bars: 200 µm. d ANXA7 mRNA level in mice after 0 h, 6 h, 12 h, 24 h, 3 d and 5 d of spinal cord injury. e, f Protein level of ANXA7 in neuron after 24 h of spinal cord injury detected by immunohistochemistry staining. g–i Neurons were treated with 0.1% DMSO, SEC or ABO separately 1 h before OGD/R treatment, and CCK-8 assay was used to detect survival ratio of neurons. Data are presented as means ± SD, * P < 0.05, ** P < 0.01, *** P < 0.001, n = 3.

Fig 4: ANXA7 is beneficial to the recovery of motor function after spinal cord injury in mice.a C57BL/6 mice were used for establishing spinal cord injury models. SEC at a dose of 10 mg/kg/2d was injected by tail vein injection for three times before SCI treatment. OE-ANXA7 lentivirus was injected into spinal cord 3 days before SCI treatment. b–d Footprint images of mice in groups of sham, SCI + PBS and SCI + SEC. e BMS scores of sham, SCI + PBS and SCI + SEC groups. f–i Max contact area, Print area, Mean intensity and Base of support index of sham, SCI + PBS and SCI + SEC group. j–l Footprint images of mice in groups of sham, SCI + NC, and SCI + OE-ANXA7 group. m BMS scores of sham, SCI + NC, and SCI + OE-ANXA7 group. n–q Max contact area, Print area, Mean intensity and Base of support index of sham, SCI + NC, and SCI + OE-ANXA7 group. CatWalk analysis were conducted 6 weeks after spinal cord injury, while BMS score experiments were performed 1 day and every week after spinal cord injury in mice. BMS score is presented as means ± SD, while other data are presented as means ± SEM, * P < 0.05, ** P < 0.01, *** P < 0.001, n = 5.

Fig 5: ANXA7 interacts with LAMP5 to stabilize its expression.a, b LAMP5 protein expression was detected in spinal cord 24 h after SCI. c Immunofluorescence was used to detect the co-localization between ANXA7 and LAMP5 in neurons. Scale bars: 10 µm. d ImageJ analysis the co-localization of ANXA7 and LAMP5. e, f Co-immunoprecipitation to detect the interaction between ANXA7 and LAMP5 after OGD/R treatment. g Immunofluorescence was used to detect LAMP5 expression and the co-localization between ANXA7 and LAMP5 in neurons after OGD/R, SEC + OGD/R and ABO + OGD/R treatment. Scale bars: 10 µm. h–k ImageJ analysis the co-localization of ANXA7 and LAMP5 in CTR, OGD/R, SEC + OGD/R and ABO + OGD/R treatment group. l, m Data analysis of Fig. 5g. Data are presented as means ± SD, * P < 0.05, ** P < 0.01, n = 3.