Fig 1: Rescuing TBX20 expression by AAV-mediated gene delivery restored itch response in TBX20fl/fl; Avil-Cre mice, while NRG1 inhibited TBX20 expression, reducing MC903-induced itch and immune cell infiltration in the ear model.a Schematic of the AAV-mediated TBX20 expression strategy in TBX20fl/fl;K14-Cre mice in the MC903-induced cheek model. AAV-Control is the negative control for AAV-TBX20. b Immunofluorescence images of TBX20 in the cheek skin following AAV-TBX20 or AAV-Control administration in the skin of TBX20fl/fl; K14-Cre mice, harvested on day 13. Experiments were independently repeated three times with similar results. Representative data and images are shown in the figures. Scale bar = 50 μm. Comparison of scratching bouts between AAV-TBX20 and AAV-Control injected TBX20fl/fl; K14-Cre mice in the MC903 cheek model. c Total number of scratching bouts on day 11. d Time-resolved analysis of scratching behaviour. N = 7 mice/group. e RT-qPCR analysis of Tbx20 and Npr1 transcript levels on MC903-cheek skin samples comparing AAV-TBX20 and AAV-Control injected TBX20fl/fl; K14-Cre mice (n = 3 mice/group). f Strategy of NRG1 administration in WT mice, followed by the establishment of the MC903-induced ear model. g Total number of scratching bouts in the MC903 ear model, comparing NRG1- and vehicle- treated WT mice (n = 5 mice/group). h RT-qPCR analysis of the effect of NRG1 on TBX20 and NPR1 transcripts in IL-13-stimulated human primary keratinocytes (NHEK) cells. N = 8 independent cultures for h (left) and n = 10 for h (right). i Representative immunohistochemistry images of ear skin from the MC903-induced model following NRG1 treatment, showing infiltration of Mcpt8+, CD68+ and CD11b+ cells. Bar-charts quantify immune cell infiltration in MC903-treated ear skin (n = 3 mice/group). Scale bar = 50 μm. Illustrations in (a) and (f) were created in BioRender. Meng, J. (2026) https://BioRender.com/q7b654v. Data presented as Mean ± SEM; a two-tailed unpaired Student’s t-test (c–g, and i) or 2-way ANOVA followed by Bonferroni’s multiple comparisons test (h) was used. nsP > 0.05, *P < 0.05, **P < 0.01, ***P < 0.001, ****P<0.0001. Source data (c, d–i) are provided as a Source Data file.