Fig. 2

Involvement of aged MSCs in the development of inflammaging.

Ageing MSCs secrete a large amount of SASP factors, favouring the formation of an inflammatory microenvironment. Debris produced in aged MSCs can be considered a kind of DAMP and induces macrophage activation through receptors expressed on these cells; for example,, TLR4, NLR4 and RAGE. Aged MSCs promote monocyte recruitment by secreting ligands of CCR2 and induce the shift of macrophages from the M2 to the M1 phenotype. The immunosuppressive capacity of MSCs decreases with ageing and manifests by the reduced inhibitory effects of T cells mediated through IL-6, IL-8, CCL2, and miRNA carried by EVs and ROS production