The role of p21 in cellular senescence and aging-related diseases

Phenotypic changes associated with continuous long term in vitro expansion of bone marrow-derived mesenchymal stem cells

In vitro expansion of mesenchymal stem cells is necessary to obtain a higher cell number for clinical applications. However, long-term expansion can produce significant phenotypic changes on these cells, decreasing their therapeutic utility. Therefore, understanding the phenotypic changes that long-term expansion triggers in mesenchymal stem cells will allow for better and more consistent cell therapy results. Here, we evaluate the phenotypic changes caused by continuous passaging through colony forming unit-fibroblast assay, senescence beta-galactosidase staining, morphology examination, secretome analysis, surface marker expression, protein quantification, osteogenic and adipogenic differentiation, and CD4+ T lymphocyte immunosuppressive potential. Long-term in vitro culture decreases mesenchymal stem cell osteogenic potential and self-renewal, increases cell size, and senescence, but does not consistently affect adipogenic differentiation. Surface marker expression remains similar for positive and negative markers, while secretory phenotype shifts with decreased p14ARF, MMP-3, p21 Waf1/Cip1,ENA-78, GCP-2, GROα, IL-3, IL-7, IL-8, RANTES, TNFβ, and VEGF-A expression, and increased p53, p16 INK4a, MCP-1, and SDF-1 expression. Immunomodulatory potential remains unchanged. These findings can help better understand the phenotypic changes that mesenchymal stem cells undergo while expanded in vitro.

CDKN1A as a potential target for Eltrombopag treatment in ITP and its regulation of the communication between macrophages and transitional B cells in ITP

This study aimed to identify novel biomarkers associated with Eltrombopag response in patients with immune thrombocytopenia (ITP) and to investigate the role of macrophage and transitional B cells in ITP pathogenesis. Differentially expressed genes were identified using the GSE112278 dataset, followed by weighted gene co-expression network analysis (WGCNA) to screen hub genes. Single-cell RNA-seq data from GSE196676 were analyzed using the Seurat package to assess immune cell composition, gene expression, and cell-cell communication. CDKN1A expression was experimentally modulated in RAW264.7 macrophages via siRNA knockdown or plasmid overexpression. Phagocytic function was assessed using CFDA-labeled mouse platelets and F4/80 immunofluorescence staining. Molecular docking was conducted to evaluate the interaction between Eltrombopag and CDKN1A. Through intersection analysis, we identified CDKN1A as a key gene influencing the response of ITP patients to Eltrombopag treatment. Single-cell data analysis revealed a significant increase in the proportion of macrophages in ITP patients, accompanied by downregulation of CDKN1A expression in these macrophages, which was closely associated with macrophage activation and enhanced phagocytic capacity. Functional experiments confirmed that CDKN1A knockdown promoted, while overexpression inhibited, macrophage phagocytosis of platelets. Additionally, cell communication analysis demonstrated that macrophages in ITP patients interact with transitional B cells via the TGFβ signaling pathway. Further analysis revealed that a subset of macrophages performs effector functions by differentiating into specialized subtypes that function independently, without direct interaction with other immune cells. Our study identified CDKN1A as a key regulator of Eltrombopag's effectiveness in treating ITP. CDKN1A expression was reduced in macrophages of ITP patients and that it interacted with transitional B cells through the TGFβ signaling pathway to promote disease progression. These findings offer new insights into the pathogenic mechanisms of ITP and suggest CDKN1A as a potential therapeutic target for future interventions.

Kisspeptin-10 Protects Against TNF-α-Induced Chondrocyte Senescence via the SIRT1/p53/p21 Signaling

In Osteoarthritis (OA), the senescence of chondrocytes plays a pivotal role, contributing to cartilage degradation and impairing tissue repair mechanisms. (Kp-10), a peptide hormone, exerts diverse biological functions across multiple cell types and tissues via its receptor Gpr54. However, its role in chondrocytes and OA has been understudied. This study investigates the role of Kp-10 in mitigating TNF-α- induced senescence in primary chondrocytes, a hallmark of OA pathogenesis. Gpr54 expression was confirmed in both primary chondrocytes and the ATDC5 chondrogenic cell line, with TNF-α treatment leading to a dose-dependent decrease in Gpr54 expression. Kp-10 treatment at concentrations of 50 and 100 nM effectively ameliorated TNF-α-induced senescence, as evidenced by diminished senescence-associated β-galactosidase staining and enhanced telomerase activity. Moreover, Kisspeptin-10 modulated the expression of key regulators involved in cellular aging, including hTERT and TERF2, and suppressed the activation of the p53/p21 pathway. Notably, Kp-10 restored SIRT1 expression, which was downregulated by TNF-α. Silencing SIRT1 abolished the protective effects of Kp-10, highlighting the essential role of SIRT1 in its anti-senescence action. These findings suggest that Kp-10 may be a promising therapeutic strategy for OA by mitigating chondrocyte senescence and improving cellular function by modulating the SIRT1 and p53/p21 pathways.

Imbalanced redox dynamics induce fibroblast senescence leading to impaired stem cell pools and skin aging

Skin function depends on a meticulously regulated dynamic interaction of distinct skin compartments such as the epidermis and dermis. Adaptive responses at the molecular and cellular level are essential for these interactions - and if dysregulated - drive skin aging and other pathologies. After defining the role of redox homeodynamics in physiology and aging pathology, we focus on the redox distress-dependent aging of dermal fibroblasts including their progenitors. We here discuss the prime role of senescent fibroblasts in the control of their own endogenous niche and stem cell niches for epidermal stem cells, hair follicle stem cells, adipocyte precursors and muscle stem cells. We here review that redox imbalance induced reduction in Insulin-like Growth Factor-1 drives skin aging by the depletion of stem cell pools. This IGF-1 reduction is mediated via the redox-sensitive transcription factor JunB and also by the redox-dependent changes in sphingolipid-metabolism, among others. In addition, we will discuss the changes in the extracellular matrix of the skin affecting cellular senescence and the skin integrity and function in aging. The aim is a deeper understanding of the two main redox-dependent hubs such as JunB-induced depletion of IGF-1, and the sphingolipid-mediated remodeling of the cell membrane with its impact on IGF-1, fibroblast heterogeneity, function, senescence and plasticity in skin aging.

Targeting p53-p21 signaling to enhance mesenchymal stem cell regenerative potential

Mesenchymal stem cells (MSCs) are properties of self-renewal and differentiation potentials and thus are very appealing to regenerative medicine. Nevertheless, their therapeutic potential is frequently constrained by senescence, limited proliferation, and stress-induced apoptosis. The key role of the p53-p21 biology in MSC biology resides in safeguarding genomic stability while promoting senescence and limiting regenerative capacity upon over-activation demonstrated. This pathway is a key point for improving MSC function and exploiting the inherent limitations. Recent advances indicate that senescence can be delayed by targeting the p53-p21 signaling and improved MSC proliferation and differentiation capacity. PFT-α pharmacological agents transiently inhibit p53 from increasing proliferation and lineage-specific differentiation, while antioxidants such as hydrogen-rich saline and epigallocatechin 3 gallate (EGCG) suppress oxidative stress and attenuate p53 p21 signaling. Genetic tools like CRISPR-Cas9 and RNA interference also precisely modulate TP53 and CDKN1A expression to optimize MSC functionality. The interplay of p53-p21 with pathways like Wnt/β-catenin and MAPK further highlights opportunities for combinatorial therapies to enhance MSC resilience and regenerative outcomes. This review aims to offer a holistic view of how p53-p21 targeting can further the regenerative potential of MSCs, resolving senescence, proliferation, and stress resilience towards advanced therapeutics built on MSCs.

Oncogenic role of fumarate hydratase in breast cancer: metabolic reprogramming and mechanistic insights

Breast cancer remains the most prevalent malignancy among women globally, with its complexity linked to genetic variations and metabolic alterations within tumor cells. This study investigates the role of fumarate hydratase (FH), a key enzyme in the tricarboxylic acid (TCA) cycle, in breast cancer progression. Our findings reveal that FH mRNA and protein levels are significantly upregulated in breast cancer tissues and correlate with poor patient prognosis and aggressive tumor characteristics. Using in vitro and in vivo models, we demonstrate that FH overexpression enhances breast cancer cell proliferation, migration, and invasion through metabolic reprogramming and by increasing reactive oxygen species (ROS) production. Furthermore, we identify matrix metalloproteinase 1 (MMP1) as a downstream effector of FH, linked to p21 downregulation, elucidating a novel regulatory pathway influencing tumor behavior. Interestingly, unlike its tumor-suppressing role in other cancer types, this study highlights FH's oncogenic potential in breast cancer. Our results suggest that FH enhances cancer cell viability and aggressiveness via both catalytic and non-catalytic mechanisms. This work not only underscores the metabolic adaptations of breast cancer cells but also proposes FH as a potential biomarker and therapeutic target for breast cancer management.

Advances in Molecular Research of Tracheobronchial Tree Aging: A Systematic Review

Aging affects all tissues in an organism, including the tracheobronchial tree, with structural and functional changes driven by mechanisms such as oxidative stress, cellular senescence, epigenetic modifications, mitochondrial dysfunction, and telomere shortening. Airway aging can be accelerated by intrinsic or extrinsic factors. This review brings together information from the literature on the molecular changes occurring in all layers of the tracheobronchial airway wall. It examines the biomolecular changes associated with aging in the mucosa, submucosa, cartilage, and smooth muscle of the airways. At the mucosal level, aging reduces ciliary function and disrupts mucin homeostasis, impairing mucociliary clearance and contributing to chronic respiratory diseases such as COPD (Chronic Obstructive Pulmonary Disease). Cellular senescence and oxidative stress drive extracellular matrix remodeling and chronic inflammation. Airway cartilage undergoes age-related changes in collagen and fibronectin composition, leading to increased stiffness, while heightened MMP (Matrix Metalloproteinases) activity exacerbates ECM (extracellular matrix) degradation. In airway smooth muscle, aging induces changes in calcium signaling, hypertrophy, and the secretion of pro-inflammatory mediators, further perpetuating airway remodeling. These changes impair respiratory function and increase susceptibility to chronic respiratory conditions in the elderly. By consolidating current knowledge, this review aims to provide a comprehensive overview of the molecular changes occurring in the respiratory tract with aging and to highlight new molecular perspectives for future research on this topic.

Endothelial c-REL orchestrates atherosclerosis at regions of disturbed flow through crosstalk with TXNIP-p38 and non-canonical NF-κB pathways

AIMS

Atherosclerosis initiation at sites of disturbed blood flow involves heightened inflammation coupled to excessive endothelial cell (EC) proliferation. Here, we unveil the pivotal role of c-REL, a member of the NF-κB transcription factor family, in orchestrating these processes by driving dual pathological inflammatory and cell cycle pathways.

METHODS AND RESULTS

Analysis of cultured EC and murine models revealed enrichment and activation of c-REL at atherosusceptible sites experiencing disturbed flow. Transcriptome analysis, extensively validated in vitro and in vivo, demonstrates that endothelial c-REL drives inflammation via a TXNIP-p38 MAP kinase signalling pathway and enhances proliferation through a non-canonical NFKB2-p21 pathway. Consistent with its pivotal role in EC pathology, genetic deletion of c-Rel in EC significantly reduces plaque burden in hypercholesterolaemic mice.

CONCLUSION

These findings underscore the fundamental role of c-REL in endothelial responses to disturbed flow and highlight therapeutic targeting of endothelial c-REL as a potential strategy for atherosclerosis treatment.

Multifaceted role of zipper-interacting protein kinase beyond cell death: Implication of ZIPK dysregulation in neuronal and vascular injuries

Zipper-interacting protein kinase (ZIPK) belongs to the death-associated protein kinase (DAPK) family and is a serine/threonine kinase. ZIPK is ubiquitously expressed in different types of tissues and cells. ZIPK is involved in many cellular functions, including cell death, smooth muscle contraction, transcriptional regulation, inflammatory signaling and the regulation of angiogenesis. The dysregulation of ZIPK has been shown to be involved in multiple diseases, including cancer, neurological diseases such as stroke, and cardiovascular diseases such as hypertension. The molecular mechanisms by which ZIPK inhibits the development of cancer have been well studied, but less is known about how ZIPK dysregulation is involved in vascular and neurological diseases. In this review, we summarize the current knowledge about the cellular processes in which ZIPK is involved and the pathological relevance of ZIPK dysregulation in diseases, with a focus on the role of ZIPK in vascular and neuronal functions. The molecular mechanisms by which ZIPK dysregulation contributes to cancer and vascular and neuronal diseases are discussed. We also review recent advances in the development of ZIPK modulators and their potential in treating vascular damage and neurological disorders. Multiple findings support that ZIPK has important functions in regulating vascular homeostasis and serves as a novel therapeutic target for alleviating neurological diseases.

Downregulation of EZH2 Promotes Renal Epithelial Cellular Senescence and Kidney Aging

Renal epithelial cell senescence and kidney aging have become the focus of scientific investigation. However, how epigenetic regulation in these processes remains elusive. Enhancer of zeste homolog 2 (EZH2), a histone methyltransferase, regulates trimethylation of histone H3 at lysine 27 (H3K27me3) and plays an important role in renal pathophysiology. In this study, we show that the expression of EZH2 is decreased in naturally aged and irradiation (IR)-induced mouse kidneys, as well as in IR-induced human renal cortical tubular epithelial (RCTE) cells through proteasome-mediated degradation. Inhibition of EZH2 with its specific inhibitor 3-DZNeP promotes tubular cell senescence and kidney aging characterized by an increase in the expression of senescence markers, including p16 and p21, in mouse kidneys and in IR-induced RCTE cells. We show that EZH2 represses the transcription of p16 through trimethylation of H3K27me3, which directly binds to the promoter of p16. EZH2 represses the transcription of p21 through directly binding to the promoter of p21, and this process is involved in its interaction with p53 and its phosphorylation by ataxia-telangiectasia mutated (ATM), a critical protein involved in the cellular response to DNA damage. Inhibition of ATM with its inhibitor decreased the phosphorylation of EZH2 and the binding of EZH2 to the promoter of p21 in IR-treated RCTE cells in a p53-dependent manner. This study suggests that EZH2 plays a critical role in preventing kidney aging and DNA-damage-induced renal tubular cellular senescence, in which senescence and kidney aging also result in the destabilization of EZH2, forming a negative feedback loop.

Epidermal loss of PRMT5 leads to the emergence of an atypical basal keratinocyte-like cell population and defective skin stratification

During skin development, ectoderm-derived cells undergo precisely coordinated proliferation, differentiation, and adhesion to yield stratified epidermis. Disruptions in these processes can result in congenital anomalies including ectodermal dysplasia and harlequin ichthyosis. Protein Arginine Methyl Transferase 5 (PRMT5)-an enzyme responsible for methylating arginine residues in histones and other proteins-maintains progenitor status in germ and limb bud cells. Similarly, in vitro evidence suggests that PRMT5 prevents differentiation of basal keratinocytes, leading us to hypothesize that PRMT5 preserves the stem-cell phenotype of keratinocytes in vivo. To test this possibility, we generated conditional knockout (cKO) mice lacking Prmt5 in early ectoderm (E7.5), impacting the entire epidermis. Prmt5 cKOs exhibited gross skin defects, compromised skin barrier function, and reduced postnatal viability. Histological analyses revealed significant defects in epidermal stratification, without alterations in apoptosis or proliferation. Single-cell RNA and ATAC-seq analysis identified an atypical population of basal keratinocyte-like cells in Prmt5 cKOs, that exhibited a senescence-like program, characterized by increased Cdkn1a (p21), elevated senescence-associated secretory phenotype (SASP) molecules (Igfbp2), and decreased developmental transcription factor (Trp63) expression. Our findings suggest that PRMT5 prevents basal keratinocyte senescence by repressing Cdkn1a, shedding light on the epigenetic regulation of basal keratinocyte maintenance and senescence in congenital skin disorders.

Quercetin as a therapeutic agent for skin problems: a systematic review and meta-analysis on antioxidant effects, oxidative stress, inflammation, wound healing, hyperpigmentation, aging, and skin cancer

Quercetin is abundant in plants and has notable pharmacological properties for skin health. This review aims to comprehensively evaluate the effects of quercetin on skin-related issues, adhering to the PRISMA guidelines and analyzing studies from ScienceDirect, Web of Science, Scopus, and PubMed. Of the 1,398 studies identified, 65 studies met the criteria for meta-analysis. The meta-analysis indicated that quercetin had powerful antioxidant properties, protecting against oxidative stress by significantly lowering levels of MDA (Z-score, 2.51), ROS (Z-score, 3.81), and LPO (Z-score, 4.46), and enhancing enzymes of GSH (Z-score, 5.46), CAT (Z-score, 5.20), and SOD (Z-score, 4.37). Quercetin acted as an anti-inflammatory by significantly suppressing protein regulators such as NF-κβ, AP-1, and MAPKs (ERK and JNK), cytokines of TNFα, IL-6, IL-1β, IL-8, and MCP-1, and enzymes of COX-2, iNOS, and MPO, while upregulating the cytokine IL-10. Additionally, quercetin significantly suppressed IL-4 (Z-score, 3.16) and IFNγ (Z-score, 3.76) cytokines involved in chronic inflammation of atopic dermatitis. Quercetin also supported wound healing by significantly decreasing inflammatory cells (Z-score, 5.60) and enhancing fibroblast distribution (Z-score, 5.98), epithelialization (Z-score, 8.57), collagen production (Z-score, 4.20), and angiogenesis factors of MVD (Z-score, 5.66) and VEGF (Z-score, 3.86). Furthermore, quercetin significantly inhibited tyrosinase activity (Z-score, 1.95), resulting in a significantly reduced melanin content (Z-score, 2.56). A significant reduction in DNA damage (Z-score, 3.27), melanoma cell viability (Z-score, 2.97), and tumor formation was also observed to ensure the promising activity of quercetin for skin issues. This review highlights quercetin's potential as a multifaceted agent in skin care and treatment.

8-Oxoguanine modifications in peripheral leukocyte microRNAs promote age-related inflammation by remodeling gene regulatory networks

The role of reactive oxygen species (ROS) in cellular senescence and inflammation has been extensively studied; however, the specific molecular mechanisms underlying these effects have yet to be fully elucidated. By applying a nucleotide pool detection system, oxidative microRNA sequencing, and cytokine chip detection techniques, we found that the levels of 8-oxo-guanosine triphosphate (8-oxo-GTP) increased with age and were positively correlated with elevated levels of oxidized microRNA and increased levels of inflammatory factors. During aging, guanine residues in the seed regions of miR-98-5p that regulates ICAM1, and miR-8085 that regulates CXCL16, were oxidized to 8-oxoguanine. This oxidation weakened the binding affinity of microRNAs to their target genes, thereby promoting the expression of ICAM1 and CXCL16. Oxidized microRNAs can regulate new target genes via o8G:A base mismatches. Our findings reveal that ROS-induced oxidative modifications of microRNAs reshape gene regulatory networks, activate inflammatory pathways, providing new insights into the mechanisms of age-related inflammation.

Dose-dependent effects of curcumin on 22Rv1 prostate cancer cell line

BACKGROUND

Prostate cancer (PCa) is the second most frequent cancer type in the male population over 66 years. Curcumin is a polyphenolic natural compound extract from the rhizomes of Curcuma longa Linn (Zingiberaceae family) which showed important anticancer effects by inhibiting cell proliferation and inducing apoptosis in several cancer types. Recently, some studies reported that oral curcumin lowered PSA levels, but it did not modify the clinical outcomes in patients with prostate cancer who received intermittent androgen deprivation (IAD). Other studies reported that high concentrations of curcumin were toxic for patients.

METHODS AND RESULTS

In this study we showed that low doses of curcumin can induce senescence-like effects in 22Rv1 cell line while higher concentrations have cytotoxic effects. Five,15 and 30 µM curcumin blocked cell cycle in G2/M phase but only 15 and 30 µM curcumin induced cell death. In addition, an increased expression of p21, a known senescence marker, was detected in 22Rv1 cells treated with curcumin in every experimental condition. However, the expression of p16, another known senescence marker, increased only to 30 µM curcumin.

CONCLUSION

In the context of personalized approach in PCa care, we suggest that the appropriate concentration of curcumin used in combination with radiotherapy or with androgen deprivation therapy (ADT) could be taken into consideration.

Anti-Hair Loss Effect of Veratric Acid on Dermal Papilla Cells

The activation of hair follicle dermal papilla cells (HFDPCs), a critical target of hair loss relief, can be achieved through the upregulation of proliferation, the stimulation of hair inducibility, and the inhibition of cellular senescence. Veratric acid (VA) is a major benzoic acid found in fruits and vegetables. The biological activity of VA on HFDPCs remains to be elucidated. In this study, we investigated the capacity of VA for hair loss mitigation. An MTT assay, Ki67 staining, quantitative RT-PCR (qRT-PCR), and a Western blot analysis were performed to confirm the proliferative effect of VA. Hair inductivity was determined through a cell aggregation assay and ALP staining. Annexin V/PI staining was performed to confirm the anti-apoptotic effect of VA. The inhibitory effect of VA on cellular senescence was confirmed by a β-galactosidase (β-gal) assay and qRT-PCR using replicative senescence and oxidative stress-induced senescence models. As a result, VA dose-dependently upregulated the proliferation of HFDPCs, the expression of growth factors, and β-catenin protein levels. VA also dose-dependently increased ALP activity and cell aggregation and decreased apoptotic cells through the regulation of BCL2 and BAX expression. Moreover, VA reduced β-gal activity and the senescence-associated secretory phenotype (SASP) in a dose-dependent manner in senescent HFDPCs. These findings suggest that VA may serve as a potential therapeutic agent for alleviating hair loss by targeting multiple pathways involved in HFDPC activation.

Cell enlargement modulated by GATA4 and YAP instructs the senescence-associated secretory phenotype

Dynamic changes in cell size are associated with development and pathological conditions, including aging. Although cell enlargement is a prominent morphological feature of cellular senescence, its functional implications are unknown; moreover, how senescent cells maintain their enlargement state is less understood. Here we show that an extensive remodeling of actin cytoskeleton is necessary for establishing senescence-associated cell enlargement and pro-inflammatory senescence-associated secretory phenotype (SASP). This remodeling is attributed to a balancing act between the SASP regulator GATA4 and the mechanosensor YAP on the expression of the Rho family of GTPase RHOU. Genetic or pharmacological interventions that reduce cell enlargement attenuate SASP with minimal effect on senescence growth arrest. Mechanistically, actin cytoskeleton remodeling couples cell enlargement to the nuclear localization of GATA4 and NF-κB via the Linker of Nucleoskeleton and Cytoskeleton (LINC) complex. RhoU protein accumulates in mouse adipose tissue under senescence-inducing conditions. Furthermore, RHOU expression correlates with SASP expression in adipose tissue during human aging. Thus, our study highlights an unexpected instructive role of cell enlargement in modulating the SASP and reveals a mechanical branch in the senescence regulatory network.

Avid lysosomal acidification in fibroblasts of the Mediterranean mouse Mus spretus

Failures of the lysosome-autophagy system are a hallmark of aging and many disease states. As a consequence, interventions that enhance lysosome function are of keen interest in the context of drug development. Throughout the biomedical literature, evolutionary biologists have discovered that challenges faced by humans in clinical settings have been resolved by non-model organisms adapting to wild environments. Here, we used a primary cell culture approach to survey lysosomal characteristics in selected species of the genus Mus. We found that cells from M. musculus, mice adapted to human environments, had weak lysosomal acidification and high expression and activity of the lysosomal enzyme β-galactosidase, a classic marker of cellular senescence. Cells of wild relatives, especially the Mediterranean mouse M. spretus, had more robustly performing lysosomes and dampened β-galactosidase levels. We propose that classic laboratory models of lysosome function and senescence may reflect characters that diverge from the phenotypes of wild mice. The M. spretus phenotype may ultimately provide a blueprint for interventions that ameliorate lysosome breakdown in stress and disease.

Curcumin nanoparticles alleviate brain mitochondrial dysfunction and cellular senescence in γ-irradiated rats

Despite the diverse applications of γ radiation in radiotherapy, industrial processes, and sterilization, it causes hazardous effects on living organisms, such as cellular senescence, persistent cell cycle arrest, and mitochondrial dysfunction. This study evaluated the efficacy of curcumin nanoparticles (CNPs) in mitigating mitochondrial dysfunction and cellular senescence induced by γ radiation in rat brain tissues. Four groups of male Wistar albino rats (n = 8 per group) were included: (Gr1) the control group; (Gr2) the CNPs group (healthy rats receiving oral administration of curcumin nanoparticles at a dose of 10 mg/kg/day, three times per week for eight weeks); (Gr3) the irradiated group (rats exposed to a single dose of 10 Gy head γ irradiation); and (Gr4) the irradiated + CNPs group (irradiated rats treated with CNPs). The data obtained demonstrated that oral administration of CNPs for eight weeks attenuated oxidative stress in γ-irradiated rats by lowering the brain's lipid peroxidation level [malondialdehyde (MDA)] and enhancing antioxidant markers [superoxide dismutase (SOD), reduced glutathione (GSH), and total antioxidant capacity (TAC)] (P < 0.05). In addition, CNPs significantly increased mitochondrial function by improving complex I, complex II, and ATP production levels compared to the irradiated group. In irradiated rats, CNPs also showed anti-neuroinflammatory effects by reducing brain interleukin 6 (IL-6), tumor necrosis factor-alpha (TNF-α), and nuclear factor-kappa B (NF-ĸB) levels (P < 0.05). Moreover, CNPs administered to irradiated rats significantly reduced brain β-galactosidase activity and the expression levels of p53, p21, and p16 genes (P < 0.05) while concurrently inducing a significant increase in AMPK mRNA expression compared to the irradiated group. In conclusion, CNPs ameliorated the neurotoxicity of γ radiation and hold promise as a novel agent to delay cellular senescence via their combined antioxidant, anti-inflammatory, and mitochondrial-enhancing properties.

Cellular senescence: A new perspective on the suppression of periodontitis (Review)

Cellular senescence, characterized by cell cycle arrest, can result in tissue dysfunction when senescent cells persist and accumulate. Periodontitis, a chronic inflammatory condition caused by the interaction between bacteria and the immune system of the host, primarily manifests as damage to periodontal tissues. Aging and inflammation are interlinked processes that exacerbate each other. The progression of localized chronic periodontal inflammation is often accelerated in conjunction with tissue and organ aging. The presence of senescent cells and release of inflammatory cytokines, immune modulators, growth factors and proteases that are associated with the senescence‑associated secretory phenotype contribute to the deterioration of periodontal tissues. The present review aimed to elucidate the mechanisms of cellular senescence and its potential impact on periodontitis, offering novel insights for modulating the inflammatory microenvironment of periodontal tissues.