Table 5.

Precondition of MSCs to enhance their immunomodulatory function.

Precondition	Factors	Effectiveness	Reference
Hypoxia	HIF-1α	Impair DCs differentiation, and reduce NK cell-mediated cell lysis	[101]
	miR-146a-5p	Enhance the immunoregulatory effects	[102]
Immunomodulatory factors	IFN-γ	Suppress activated T cells and stimulate Treg	[103]
		Upregulate the expression level of PD-L1 in monocytes	[104]
	TGF-β and IL-6	Enhance adhesion of MSCs through IL-6/ SHP2/integrin signaling axis	[105]
3D culture	Exosomes	Exert greater inhibitory influence on PBMC proliferation.	[106]
	PGE2 and TSG6	Suppress LPS-stimulated macrophages polarization	[107, 110]