CD4 and periodontitis: reported miR‐155‐5p regulated Th17/Treg cells balance by targeting Sirt1, thereby alleviating chronic periodontitis.[48] Similarly, targeting Sirt1 mitigated Graft‐versus‐Host Disease development by inhibiting alloreactive T cell activation and promoting Tregs stability in mice.[49] In this regard, 3D‐Exos‐derived miR‐132‐3p probably promoted the differentiation of Treg cells by inhibiting Sirt1 expression in CD4+T cells.