Epithelial–mesenchymal transitions (EMTs) are the epitome of cell plasticity in embryonic development and cancer; during EMT, epithelial cells undergo dramatic phenotypic changes and become able to migrate to form different tissues or give rise to metastases, respectively. The importance of EMTs in other contexts, such as tissue repair and fibrosis in the adult, has become increasingly recognized and studied. In this Review, we discuss the function of EMT in the adult after tissue damage and compare features of embryonic and adult EMT. Whereas sustained EMT leads to adult tissue degeneration, fibrosis and organ failure, its transient activation, which confers phenotypic and functional plasticity on somatic cells, promotes tissue repair after damage. Understanding the mechanisms and temporal regulation of different EMTs provides insight into how some tissues heal and has the potential to open new therapeutic avenues to promote repair or regeneration of tissue damage that is currently irreversible. We also discuss therapeutic strategies that modulate EMT that hold clinical promise in ameliorating fibrosis, and how precise EMT activation could be harnessed to enhance tissue repair.

上皮-间质转化（EMT）是胚胎发育和癌症中细胞可塑性的缩影；在 EMT 期间，上皮细胞经历显着的表型变化，并能够分别迁移形成不同的组织或引起转移。 EMT 在其他情况下的重要性，例如成人的组织修复和纤维化，已得到越来越多的认识和研究。在这篇综述中，我们讨论了组织损伤后成人中 EMT 的功能，并比较了胚胎和成人 EMT 的特征。持续的 EMT 会导致成体组织退化、纤维化和器官衰竭，而其短暂的激活会赋予体细胞表型和功能可塑性，从而促进损伤后的组织修复。了解不同 EMT 的机制和时间调节可以深入了解某些组织如何愈合，并有可能开辟新的治疗途径，以促进目前不可逆转的组织损伤的修复或再生。我们还讨论了调节 EMT 的治疗策略，这些策略在改善纤维化方面具有临床前景，以及如何利用精确的 EMT 激活来增强组织修复。