Abstract
Chronic, non-healing wounds are a severe diabetic complication. The underlying mechanisms are not fully understood, and the role of ATF7 in this context has not been well characterized. In our study, we utilized db/db diabetic mice and AAV-mediated keratinocyte-specific Atf7 overexpression in vivo. HaCaT keratinocyte/THP-1 macrophage cocultures under high glucose were used in vitro. Our results showed that ATF7 was upregulated in diabetic wounds. Keratinocyte-specific Atf7 overexpression accelerated diabetic wound closure, enhanced re-epithelialization, granulation tissue formation, and keratinocyte proliferation, while suppressing macrophage M1 polarization and inflammation. Multiomics screening identified NOTCH1 as a key ATF7 target. ATF7 transcriptionally repressed NOTCH1 by recruiting Suv39h1, increasing H3K9me3 at the NOTCH1 promoter. This reduced NOTCH1 protein and its active intracellular domain (N1ICD) within keratinocyte-derived exosomes. ATF7-overexpressing keratinocyte exosomes carried less N1ICD, leading to decreased N1ICD transfer to macrophages and subsequent inhibition of M1 polarization. Notably, local injection of exosomes from ATF7-overexpressing keratinocytes accelerated wound healing in db/db mice. In summary, ATF7 promotes diabetic wound healing by repressing NOTCH1 transcription via H3K9me3, thereby reducing exosomal N1ICD secretion from keratinocytes and inhibiting macrophage M1 polarization. This identifies the ATF7/NOTCH1/exosome axis as a therapeutic target.
Authors
Pengcheng Xu, Yuan Xue, Linlin Feng, Jingwen Kuang, Xiaochen Hu, Huiyi Tang, Biao Cheng, Limin Wei
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