AICAR and nicotinamide treatment synergistically augment the proliferation and attenuate senescence-associated changes in mesenchymal stromal cells

Abstract

Background: Mesenchymal stromal cell (MSC) stemness capacity diminishes over prolonged in vitro culture, which negatively affects their application in regenerative medicine. To slow down the senescence of MSCs, here, we have evaluated the in vitro effects of 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR), an AMPK activator, and nicotinamide (NAM), an activator of sirtuin1 (SIRT1). Methods: Human adipose-derived MSCs were cultured to passage (P) 5. Subsequently, the cells were grown in either normal medium alone (control group), the medium supplemented with AICAR (1 mM) and NAM (5 mM), or in the presence of both for 5 weeks to P10. Cell proliferation, differentiation capacity, level of apoptosis and autophagy, morphological changes, total cellular reactive oxygen species (ROS), and activity of mTORC1 and AMPK were compared among different treatment groups. Results: MSCs treated with AICAR, NAM, or both displayed an increase in proliferation and osteogenic differentiation, which was augmented in the group receiving both. Treatment with AICAR or NAM led to decreased expression of β-galactosidase, reduced accumulation of dysfunctional lysosomes, and characteristic morphologic features of young MSCs. Furthermore, while NAM administration could significantly reduce the total cellular ROS in aged MSCs, AICAR treatment did not. Moreover, AICAR-treated cells possess a high proliferation capacity; however, they also show the highest level of cellular apoptosis. The observed effects of AICAR and NAM were in light of the attenuated mTORC1 activity and increased AMPK activity and autophagy. Conclusions: Selective inhibition of mTORC1 by AICAR and NAM boosts autophagy, retains MSCs' self-renewal and multi-lineage differentiation capacity, and postpones senescence-associated changes after prolonged in vitro culture. Additionally, co-administration of AICAR and NAM shows an additive or probably a synergistic effect on cellular senescence.

Mesenchymal Stem Cell Senescence and Rejuvenation: Current Status and Challenges

“…Autophagy has been widely employed as an anti-aging target. Inhibition of mTORC1 with AICAR and NAM boosts autophagy and retains MSC capacity for self-renewal and differentiation, and postpones senescence-associated changes (Khorraminejad-Shirazi, 2020). Hyperactivation of mTOR can negatively regulate autophagy and cause imbalance in the proteasome, ultimately leading to cellular damage and senescence.…”

Apelin Rejuvenates Aged Human Mesenchymal Stem Cells by Regulating Autophagy and Improves Cardiac Protection After Infarction

“…These results further confirmed that Apelin overexpression rejuvenates AMSCs by activating autophagy. Accumulating evidence indicates that AMPK signaling plays a critical role in regulating autophagy ( Zhao et al, 2019 ; Khorraminejad-Shirazi et al, 2020 ). Next, we investigated whether Apelin mediates autophagy levels in AMSCs via this pathway.…”

“…Given that autophagy mediates MSC senescence, activation of autophagy may be a novel strategy to rejuvenate senescent MSCs. A combination of AICAR (an AMPK stimulator) and nicotinamide (a sirtuin1 activator) was shown to synergistically improve the proliferative capacity of MSCs and ameliorate the aged phenotype by promoting autophagic activity ( Khorraminejad-Shirazi et al, 2020 ). Similarly, Apelin overexpression attenuated senescence-associated changes in AMSCs by activating AMPK signaling to enhance autophagy.…”

AKT/FOXO1 axis links cross-talking of endothelial cell and pericyte in TIE2-mutated venous malformations

“…Rapamycin (RAPA), as a mammalian TOR (mTOR) signaling inhibitor, has been approved to use for preventing the rejection of transplanted organs and to block restenosis after angioplasty [ 19 – 21 ]. RAPA inhibits the kinase activity of mTORC1 when bound to FKBP12, whereas prolonged RAPA treatment inhibits mTORC2 assembly and AKT/PKB pathway [ 22 – 24 ].…”