Nucleus pulposus (NP) cell senescence is a critical factor in the progression of intervertebral disc degeneration (IVDD). Our analysis demonstrates that FTO and YAP1 expression levels are significantly diminished in degenerative NP tissues from both human and rat models, which correlates with increased m6A modification of YAP1 transcripts. To investigate the underlying mechanisms, we utilized IL-1β to induce senescence in cultured NP cells. Our findings reveal that FTO knockdown leads to a decrease in YAP1 levels while simultaneously increasing senescence markers. In contrast, the overexpression of YAP1 alleviates the senescence phenotype in FTO-deficient cells, underscoring the protective role of YAP1 in NP cells. This study proposes a novel regulatory pathway in which FTO modulates YAP1 through m6A demethylation, suggesting potential therapeutic targets for mitigating NP cell senescence and IVDD.

Bacteria permeate every niche of the human body with major consequences on our health and senescence that have not been fully described. Here, we predict which bacteria and which bacterial proteins could interfere with proteins associated with human aging using bipartite networks showing interspecific protein interactions coupled with investigations of published experimental evidence and transcriptomic data. We introduce the term of "gerogenic" bacteria, literally bacteria that could induce some aging in their host and discuss the mechanisms by which such bacteria could serve as age-distorters of humans. Salmonella, Escherichia and Shigella appear as major candidate age-distorters, characterized by a higher experimentally demonstrated potential than other bacteria to interact with human proteins associated with human aging and human cellular senescence. Our analysis also highlights an evolutionary convergence among bacterial and viral candidate age-distorting proteins, since 14 human proteins associated with aging can be commonly targeted by bacteria and viruses in case of microbial infection. Since infections are common and Salmonella, Escherichia and Shigella are frequently found as pathogens in our microbiomes, characterizing bacterial influence on our aging and our cellular senescence through molecular hijacking could enhance the understanding of the causes of aging and suggest new anti-aging therapies.

Senescence of amnion epithelial cells not only disrupts the fetal membrane structure, but also becomes a source of proinflammatory signals contributing to membrane inflammation at parturition. However, the trigger initiating their senescence awaits identification. In this study, we found that SERPINE1 abundance was significantly increased in the amnion at parturition, where SERPINE1 was found predominantly expressed in amnion fibroblasts. SERPINE1 from amnion fibroblasts induced amnion epithelial cell senescence by causing vitronectin shedding from the cells thereby interrupting the association of vitronectin with integrin subunit αV, which led to the inhibition of the cell survival-associated focal adhesion pathway. In turn, proinflammatory cytokines such as interleukin-1β from senescent amnion epithelial cells enhanced SERPINE1 expression in amnion fibroblasts, thus forming a feed-forward loop between SERPINE1 production in amnion fibroblasts and epithelial cell senescence at parturition. Studies in the pregnant mice showed that intra-amniotic injection of SERPINE1 induced preterm birth with increased cellular senescence in the fetal membranes, which could be reversed by co-administration of vitronectin. Our findings indicate that SERPINE1 derived from amnion fibroblasts participates in the induction of amnion epithelial cell senescence at parturition. Intervening in the interaction of SERPINE1 with vitronectin may have therapeutic benefit in the treatment of preterm birth.

Sarcopenia is characterized by age-related muscle mass/function loss and fibrosis. Satellite cell (SC) dysfunction during aging promotes fibrotic transdifferentiation and extracellular matrix (ECM) deposition. Cyr61, a pro-fibrotic matricellular protein, and Wnt/β-catenin signaling pathway are implicated in muscle regeneration-fibrosis balance, but their interaction in sarcopenia remains unclear. This study first compared the expression of Cyr61 and fibrosis markers (TGF-β1, collagen type I and III) in skeletal muscle of young and old mice. In vitro, D-gal-induced C2C12 aging models were used to assess Cyr61 and Wnt signaling pathway by proliferation/apoptosis assays, ECM analysis, and detecting the changes of myogenic/fibrotic markers (MyoD, α-SMA). Pathway modulation (FH535 inhibitor/LiCl activator) and combined with Cyr61 overexpression and knockout experiments defined mechanistic roles. Cyr61 was upregulated in skeletal muscle of aged mice, which was positively correlated with increased TGF-β1 and collagen deposition. In D-gal-induced C2C12 cells showed suppressed cell proliferation, increased apoptosis and enhanced ECM deposition, accompanied by elevated Cyr61. Cyr61 knockdown or Wnt signaling pathway inhibition (FH535) reversed fibrosis (α-SMA, collagen) and restored myogenesis (MyoD).This study reveals for the first time that Cyr61 drives sarcopenic fibrosis via Wnt/β-catenin activation, promoting myocyte-to-fibrotic transition. Targeting the Cyr61-Wnt axis may ameliorate age-related muscle degeneration, warranting translational validation in preclinical models.