Skeletal muscle regeneration declines with age despite the persistence of satellite cells, indicating that regenerative impairment reflects functional dysregulation rather than stem cell loss. Increasing evidence identifies early satellite cell activation as a stress-sensitive, rate-limiting checkpoint that is preferentially disrupted in aged muscle. Integrative analyses indicate that aged satellite cells exhibit elevated stress programs and reduced membrane remodeling capacity, accompanied by weakened activa-tion-associated transcriptional signatures, while proliferative and differentiation pro-grams remain relatively accessible in successfully activated cells. This imbalance is consistent with impaired activation fidelity, in which early instability drives compen-satory downstream responses at the expense of long-term self-renewal. Within this framework, MG53 (TRIM72) is positioned beyond its canonical role in myofiber mem-brane repair as a permissive, stress-responsive regulator that stabilizes the early acti-vation environment. Rather than directly specifying cell fate, MG53 is proposed to support early activation by limiting stress-associated membrane disruption and main-taining coordination of the activation program under age-related constraints. These ob-servations suggest that restoring activation quality, rather than amplifying proliferation, may represent a more durable strategy to preserve regenerative capacity in aging skeletal muscle.

Skeletal muscle regeneration declines with age despite the persistence of satellite cells (muscle stem cells, MuSCs), suggesting that regenerative impairment reflects functional dysregulation rather than MuSC depletion. Increasing evidence identifies early MuSC activation during the immediate post-injury period as a stress-sensitive, rate-limiting transition that is particularly vulnerable in aged muscle. Aged MuSCs exhibit elevated stress responses and reduced membrane remodeling capacity, accompanied by weakened activation-associated transcriptional induction. In contrast, proliferative and differentiation programs remain largely intact once activation is successfully initiated. These findings underscore that impaired coordination during early activation contributes to long-term regenerative decline in aging. Within this framework, MG53 (tripartite motif–containing protein 72, TRIM72), a muscle-enriched TRIM family E3 ubiquitin ligase originally identified as a mediator of sarcolemmal membrane repair, may also function as a stress-responsive regulator that stabilizes the early activation environment. Rather than directly determining cell fate, MG53 is proposed to facilitate activation by mitigating stress-associated membrane disruption and maintaining programmatic coordination under age-related physiological constraints. Most mechanistic evidence derives from rodent models, and direct validation in human aging muscle remains limited. These observations suggest that targeting early activation, rather than simply increasing proliferation, may better preserve regenerative capacity in aging skeletal muscle.

The clinical use of bone graft materials for alveolar ridge preservation following tooth extraction has become a standard procedure to facilitate subsequent implant restoration and prosthetic rehabilitation. However, the therapeutic efficacy of these materials is substantially limited by their bio-inertness, lack of cellular activity, and unpredictable resorption rates. The development of bioactive osteogenic materials capable of host integration and active promotion of bone regeneration would represent a significant advancement over current clinical protocols. To address this challenge, our research has focused on developing bioactive biomaterials using human dental pulp stem cells (hDPSCs). This study proposes a novel strategy for alveolar ridge repair utilizing lyophilized hDPSC microspheres preconditioned through a three-dimensional (3D) dynamic osteogenic induction system. We cultured hDPSCs into 3D microspheres and subjected them to osteogenic induction within our established dynamic culture system, followed by lyophilization to prepare “off-the-shelf” osteogenic tissues. The resulting lyophilized microsphere constructs were implanted into fresh extraction sockets of SD rats and New Zealand white rabbits and evaluated over 4 weeks. Comparative analysis demonstrated that the lyophilized microsphere group exhibited significantly enhanced alveolar bone preservation, superior new bone formation, and improved bone microarchitecture compared to both control groups and traditional artificial bone powder groups. This preclinical study validates the potential of lyophilized hDPSC microspheres as an efficient and clinically promising bioactive material for post–extraction alveolar ridge reconstruction.