Growth arrest-specific 6 rejuvenates senescent HUCMSCs through upregulating Nrf2 for diabetic wound therapy.

GAS6 significantly improved the aging phenotype of MSCs, while siGAS6 knockdown induced MSC senescence.

• GAS6 treatment reduced senescence markers in human umbilical cord-derived MSCs (HUCMSCs) expanded ex vivo.
• siRNA-mediated knockdown of GAS6 (siGAS6) was sufficient to induce aging phenotypes in MSCs.
• Proliferative aging of ex vivo expanded MSCs was identified as a key limitation of their translational utility.
• The aging phenotype assessment included standard senescence markers consistent with MSC senescence literature.

GAS6 regulated Keap1 degradation through the p62-dependent autophagy pathway, promoting nuclear entry of Nrf2 to exert anti-aging effects.

• GAS6 promoted accumulation of p62 by activating the PI3K/Akt signaling pathway.
• p62 bound to Keap1 and promoted its degradation via autophagy.
• p62 competitively inhibited Keap1's binding to Nrf2, thereby reducing ubiquitination and degradation of Nrf2.
• Nrf2 accumulated in the cell and translocated to the nucleus, where it bound to antioxidant genes to delay MSC senescence.
• The p62-Keap1-Nrf2 axis was identified as the central mechanistic pathway through which GAS6 exerts its anti-senescence effect.

GAS6 regulated Keap1 and Nrf2 by activating the PI3K/Akt pathway, thereby delaying MSC aging.

• PI3K/Akt pathway activation by GAS6 was verified as an upstream regulator of the Keap1-Nrf2 axis.
• PI3K/Akt activation promoted p62 accumulation, linking upstream signaling to autophagic Keap1 degradation.
• GAS6 thus operates through at least two convergent mechanisms: PI3K/Akt-mediated Nrf2 regulation and p62-dependent Keap1 autophagy.

GAS6 improved the angiogenic capacity of aging MSC-derived conditioned medium (MSCs-CM) through upregulation of Nrf2.

• The angiogenic capacity of aging MSCs-CM was assessed at both cellular and animal levels.
• Upregulation of Nrf2 by GAS6 was identified as the mechanism responsible for enhanced angiogenic factors in conditioned medium.
• Aging MSCs demonstrated reduced angiogenic capacity in their conditioned medium compared to non-senescent MSCs.
• GAS6 treatment of aged MSCs restored paracrine angiogenic signaling, relevant to diabetic wound healing.

Diabetic foot ulcers represent the most severe complication of diabetes and frequently demonstrate limited response to conventional treatment, motivating MSC-based regenerative strategies.

• MSCs constitute a prospective regenerative strategy for diabetic wound healing.
• A major barrier to MSC therapy is that cells expanded ex vivo exhibit vulnerability to proliferative aging, limiting translational utility.
• GAS6's known roles in cell and tissue repair processes provided rationale for investigating its effects on MSC senescence.