Citations

Supplemental O 2 (hyperoxia) in premature infants detrimentally affects bronchial airways leading to increased senescence. Understanding the mechanisms by which hyperoxia initiates senescence in developing airways is critical for future therapeutic strategies. The current study showed that hyperoxia-induced senescence is mediated through increased mitochondrial reactive oxygen species and endoplasmic reticulum (ER) stress. ER stress inhibitors or mitochondria-targeted antioxidants may represent future therapies to blunt detrimental effects of supplemental oxygen in developing lungs.

Introduction: High-power short-duration (HPSD) ablation has emerged as a promising alternative to conventional power delivery (CPD) for pulmonary vein isolation (PVI) among patients with atrial fibrillation (AF). However, its efficacy, procedural efficiency, and safety profile remain uncertain. Methods: PubMed, Embase, Cochrane Library and ClinicalTrials.Gov databases were systematically searched for randomized controlled trials (RCTs) comparing HPSD with CPD ablation for PVI in patients with AF. Random-effects models were used to pool hazard ratios (HR) and risk ratios (RR) with 95% confidence intervals (CI). R version 4.4.2 was used for statistical analysis. Results: Seven RCTs with 1,006 patients (514 HPSD, 489 CPD) were included. No significant differences were found in freedom from arrhythmia during the follow-up period (HR 0.77; 95% CI 0.41–1.45; p=0.424). AF recurrence did not differ (RR 0.94; 95% CI 0.65–1.36; p=0.733) between groups. HPSD had a significantly shorter procedural (MD -22.61 min; 95% CI -33.18, -12.04; p<0.001) and RF ablation times (MD -15.70 min; 95% CI -20.86, -10.55; p<0.001). No differences were observed in fluoroscopy time and first-pass isolation for right and left pulmonary veins. There was no difference in esophageal lesion rates, pericardial, or neurological complications, but there was a higher incidence of steam pops in HPSD (RR 3.42; 95% CI 1.45–8.09; p=0.005). Conclusion: In patients with AF undergoing PVI, HPSD did not increase freedom from arrhythmia as compared with CPD ablation, however it was associated with shorter procedure and RF ablation times with a similar safety profile.

Abstract Senescence is a multi-functional cell fate, characterized by an irreversible cell-cycle arrest and a pro-inflammatory phenotype, commonly known as the senescence-associated secretory phenotype (SASP). Emerging evidence indicates that accumulation of senescent cells in multiple tissues drives tissue dysfunction and several age-related conditions. This has spurred the academic community and industry to identify new therapeutic interventions targeting this process. Senescence is a complex and highly heterogenous phenotype and despite tremendous progress in recent years we are still far from fully understanding it. There is no single, stand-alone marker that allows the identification of senescent cells, posing a challenge to their identification and targeting. Mitochondrial dysfunction is an often-unappreciated hallmark of cellular senescence which plays important roles not only in the senescence growth arrest but also in the development of the SASP and resistance to cell-death. In my talk, I will first describe some of our recent efforts to accurately map senescent cells in different tissues, including the application of imaging methods involving artificial intelligence. Additionally, I will describe how mitochondria contribute to the development of senescence and resistance to cell-death. Finally, I will propose that a detailed road map of mitochondrial biology in senescence will be crucial to guide the future development of therapies targeting cellular aging.

Abstract Senescence is a multi-functional cell fate, characterized by an irreversible cell-cycle arrest and a pro-inflammatory phenotype, commonly known as the senescence-associated secretory phenotype (SASP). Emerging evidence indicates that accumulation of senescent cells in multiple tissues drives tissue dysfunction and several age-related conditions. This has spurred the academic community and industry to identify new therapeutic interventions targeting this process. Senescence is a complex and highly heterogenous phenotype and despite tremendous progress in recent years we are still far from fully understanding it. There is no single, stand-alone marker that allows the identification of senescent cells, posing a challenge to their identification and targeting. Mitochondrial dysfunction is an often-unappreciated hallmark of cellular senescence which plays important roles not only in the senescence growth arrest but also in the development of the SASP and resistance to cell-death. In my talk, I will first describe some of our recent efforts to accurately map senescent cells in different tissues during aging. Additionally, I will describe how mitochondria contribute to the development of senescence and resistance to cell-death. Finally, I will propose that a detailed road map of mitochondrial biology in senescence will be crucial to guide the future development of therapies targeting cellular aging.

Abstract Senescent cells drive tissue dysfunction through the senescence-associated secretory phenotype (SASP). We uncovered a central role for mitochondria in the epigenetic regulation of the SASP, where mitochondrial-derived metabolites, specifically citrate and acetyl-CoA, fuel histone acetylation at SASP gene loci, promoting their expression. We identified the mitochondrial citrate carrier (SLC25A1) and ATP-citrate lyase (ACLY) as critical for this process. Inhibiting these pathways selectively suppresses SASP without affecting cell cycle arrest, highlighting their potential as therapeutic targets for age-related inflammation. Notably, SLC25A1 inhibition reduces systemic inflammation and extends healthspan in aged mice, establishing mitochondrial metabolism as pivotal to the epigenetic control of aging.

AbstractCellular senescence is an established cause of cell and tissue aging. Senescent cells have been shown to increase in multiple organs during aging, including the skin. Here we hypothesized that senescent cells residing in the skin can spread senescence to distant organs, thereby accelerating systemic aging processes. To explore this hypothesis, we initially observed an increase in several markers of senescence in the skin of aging mice. Subsequently, we conducted experiments wherein senescent fibroblasts were transplanted into the dermis of young mice and assessed various age‐associated parameters. Our findings reveal that the presence of senescent cells in the dermal layer of young mice leads to increased senescence in both proximal and distal host tissues, alongside increased frailty, and impaired musculoskeletal function. Additionally, there was a significant decline in cognitive function, concomitant with increased expression of senescence‐associated markers within the hippocampus brain area. These results support the concept that the accumulation of senescent cells in the skin can exert remote effects on other organs including the brain, potentially explaining links between skin and brain disorders and diseases and, contributing to physical and cognitive decline associated with aging.

Abstract Senescent cells secrete proinflammatory factors known as the senescence-associated secretory phenotype (SASP), contributing to tissue dysfunction and aging. Mitochondrial dysfunction is a key feature of senescence, influencing SASP via mitochondrial DNA (mtDNA) release and cGAS/STING pathway activation. Here, we demonstrate that mitochondrial RNA (mtRNA) also accumulates in the cytosol of senescent cells, activating RNA sensors RIG-I and MDA5, leading to MAVS aggregation and SASP induction. Inhibition of these RNA sensors significantly reduces SASP factors. Furthermore, BAX and BAK plays a key role in mtRNA leakage during senescence, and their deletion diminishes SASP expression in vitro and in a mouse model of Metabolic Dysfunction Associated Steatohepatitis (MASH). These findings highlight mtRNA's role in SASP regulation and its potential as a therapeutic target for mitigating age-related inflammation.

Cells expressing features of senescence, including upregulation of p21 and p16, appear transiently following tissue injury, yet the properties of these cells or how they contrast with age-induced senescent cells remains unclear. Here, we used skeletal injury as a model and identified the rapid appearance following fracture of p21 + cells expressing senescence markers, mainly as osteochondroprogenitors (OCHs) and neutrophils. Targeted genetic clearance of p21 + cells suppressed senescence-associated signatures within the fracture callus and accelerated fracture healing. By contrast, p21 + cell clearance did not alter bone loss due to aging; conversely, p16 + cell clearance, known to alleviate skeletal aging, did not affect fracture healing. Following fracture, p21 + neutrophils were enriched in signaling pathways known to induce paracrine stromal senescence, while p21 + OCHs were highly enriched in senescence-associated secretory phenotype factors known to impair bone formation. Further analysis revealed an injury-specific stem cell–like OCH subset that was p21 + and highly inflammatory, with a similar inflammatory mesenchymal population (fibro-adipogenic progenitors) evident following muscle injury. Thus, intercommunicating senescent-like neutrophils and mesenchymal progenitor cells were key regulators of tissue repair in bone and potentially across tissues. Moreover, our findings established contextual roles of p21 + versus p16 + senescent/senescent-like cells that may be leveraged for therapeutic opportunities.