Chronic infection with Toxoplasma gondii (T. gondii) results in severe damages to the integrity of intestinal barrier, however, both the underlying mechanism and feasible intervention strategies are still little known. Here, we found that both the chronic infection of T. gondii and transplanting gut microbiota from T. gondii-infected mice severely impaired the mice intestinal integrity, which was characterized by significantly decreased thickness of inner mucus layer and down-regulated expression of three tight junction proteins Occludin, ZO-1, and Claudin (p < 0.05). Moreover, T. gondii infection also led to mice intestinal microbiota dysbiosis, especially butyrate-producing bacteria, and significantly changed the expression of several senescence-associated markers, including 6- and 7- fold upregulation for P16, P21, and 6-fold downregulation for Lamin B1 at mRNA levels, and 2-fold downregulation for β-galactosidase at protein levels (p < 0.05). Interestingly, subsequent administration with dietary butyrate could alleviate T. gondii-induced intestinal integrity impairment and cell senescence, revealing a significant increase of the inner mucus layer thickness (p < 0.001), and a remarkable decrease in P16, P21, β-galactosidase expression levels while an upregulation of Lamin B1 expression (p < 0.05). Taken together, our study revealed that T. gondii-induced dysbiosis of gut microbiota, especially butyrate-producing bacteria, contributes to the intestinal impairment, potentially via promoting cell senescence. In addition, administration with the metabolite, butyrate, could be a promising therapeutic measure against T. gondii infection.

Cellular senescence spreads systemically through blood circulation, but its mechanisms remain unclear. High mobility group box 1 (HMGB1), a multifunctional senescence-associated secretory phenotype (SASP) factor, exists in various redox states. Here, we investigate the role of redox-sensitive HMGB1 (ReHMGB1) in driving paracrine and systemic senescence.

We applied the paracrine senescence cultured model to evaluate the effect of ReHMGB1 on cellular senescence. Each redox state of HMGB1 was treated extracellularly to assess systemic senescence both in vitro and in vivo. Senescence was determined by SA-β-gal & EdU staining, p16INK4a and p21 expression, RT-qPCR, and Western blot methods. Bulk RNA sequencing was performed to investigate ReHMGB1-driven transcriptional changes and underlying pathways. Cytokine arrays characterized SASP profiles from ReHMGB1-treated cells. In vivo, young mice were administered ReHMGB1 systemically to induce senescence across multiple tissues. A muscle injury model in middle-aged mice was used to assess the therapeutic efficacy of HMGB1 blockade.

Extracellular ReHMGB1, but not its oxidized form, robustly induced senescence-like phenotypes across multiple cell types and tissues. Transcriptomic analysis revealed activation of RAGE-mediated JAK/STAT and NF-κB pathways, driving SASP expression and cell cycle arrest. Cytokine profiling confirmed paracrine senescence features induced by ReHMGB1. ReHMGB1 administration elevated senescence markers in vivo, while HMGB1 inhibition reduced senescence, attenuated systemic inflammation, and enhanced muscle regeneration.

ReHMGB1 is a redox-dependent pro-geronic factor driving systemic senescence. Targeting extracellular HMGB1 may offer therapeutic potential for preventing aging-related pathologies.

The exact mechanisms through which chronic, low-concentration exposure to Cr(VI) facilitates the development of related pathological conditions remain to be fully elucidated. Senescence-associated secretory phenotype (SASP) exhibits a bidirectional regulatory function in biological processes. Consequently, it is essential to identify the formulation and functional characteristics of the SASP released by Cr(VI)-triggered senescent L02 hepatocytes (S-L02). In this study, exosomes were extracted from the conditioned media of both normal L02 cells and their senescent counterparts (Senescent L02, S-L02 cells). Among the miRNAs identified in the exosomes, miR-10b-3p was found to be the most abundantly expressed in the exosomes derived from S-L02 cells. As part of the SASP, miR-10b-3p was shown to suppress the proliferation of both L02 and S-L02 cells. Simultaneously, it promoted the growth, migration, and invasive capabilities of hepatocellular carcinoma (HCC) cells. The next mechanistic analysis showed that miR-10b-3p reduces the regulatory influence of the protein PHLPP2 on Akt by downregulating its target gene, PHLPP2. This suppression led to lower levels of p27, FOXO3a and p21, thereby enhancing the proliferation of HCC cells by relieving the negative regulatory mechanisms of the cell cycle. This research offers significant understanding into the oncogenic pathways induced by Cr(VI), and provides laboratory evidence for mechanistic studies targeting hepatic carcinoma associated with Cr(VI) exposure.

Mesenchymal stem cells (MSCs) derive their therapeutic potential from their secretomes, which can be modulated by external stimuli. Hypoxia is one such stimulus, and research on preconditioning MSCs with hypoxia-mimetic agents is rising. However, the effects of these preconditioning processes and the resulting metabolic status require further investigation. This study evaluated the effects of deferoxamine (DFX), a hypoxia-mimetic agent, preconditioning on MSCs in serum and serum-free environments. The influence of hypoxia on cell metabolism was examined during and after preconditioning by assessing cytotoxicity, proliferation, migration, secretomes, senescence, autophagy, and apoptosis mechanisms. The optimal DFX dose and duration for preconditioning were determined as 150 μM and 24 h based on cytotoxicity testing. Accordingly, DFX preconditioning significantly upregulated HIF-1α expression, increasing protein secretion and reducing total oxidant status. DFX appears to enhance the therapeutic potential of MSCs by increasing their secretome and antioxidant capacity. However, upon DFX removal, HIF-1α levels returned to normal, and the associated positive effects diminished. Autophagy was markedly enhanced during DFX preconditioning, potentially improving metabolic activity, preserving cellular integrity, and preparing MSCs for ischemic environments. Autophagy returned to baseline after DFX withdrawal, indicating a temporary hypoxia-mimetic response. In a serum-containing medium, specific effects of preconditioning were relatively weak to be observed. This study demonstrates that DFX-preconditioning increases MSCs' metabolic activity and enhances their adaptive cellular response. However, the effect may be transient, which provides insights into the behavior of MSCs in ischemic environments and emphasizes the need to evaluate the long-term effects of hypoxia-mimetic agents.

Cellular senescence is a state of permanent loss of proliferative capacity. Therefore, cells that reach a senescent state prevent tumor initiation, acting as an anti-tumor mechanism. However, despite not being proliferative, senescent cells have high secretory activity, constituting the Senescence-Associated Secretory Phenotype (SASP). SASP includes thousands of soluble molecules and extracellular vesicles, through which senescent cells can affect other cells and the extracellular matrix. In advanced tumors, the enrichment of senescent cells can have anti- or pro-tumor effects depending on features like SASP composition, tumor microenvironment (TME) composition, the anatomic site, histopathologic characteristics of malignancy, and tumor molecular background. We reviewed the studies assessing the impact of the senescence status, measured by mRNA or lncRNA molecular signatures, in the prognosis and other clinically relevant information in cancer, including anti-tumor immunity and response to therapy. We discussed the pros and cons of different strategies to define those molecular signatures and the main limitations of the studies. Finally, we also raised clinical challenges regarding the crossroad between cellular senescence and cancer prognosis, including some therapeutic opportunities in the field.

Partial or transient cellular reprogramming is defined by the limited induction of pluripotency factors without full dedifferentiation of cells to a pluripotent state. Comparing in vitro and in vivo mouse studies, and in vitro studies in humans, supported by visualizations of data interconnections, we show consistent patterns in how such reprogramming modulates key biological processes. Generally, partial reprogramming drives dynamic chromatin remodelling, involving histone modifications that regulate accessibility and facilitate pluripotency gene activation while silencing somatic identity. These changes are accompanied by modifications in stress response programs, such as inflammation, autophagy, and cellular senescence, as well as improved mitochondrial activity and dysregulation of extracellular matrix pathways. We also underscore the challenges in evaluating complex processes like aging and cellular senescence, given the variability in biomarkers used across studies. Overall, we highlight biological processes consistently influenced by reprogramming while noting that some effects are context-dependent, varying according to cell type, species, sex, recovery time, and the reprogramming method employed. These insights inform future research and potential therapeutic applications in aging and regenerative medicine.

Exposure to airborne particulate matter (PM) is a substantial threat to public health, contributing to respiratory, cardiovascular, and skin-related diseases. Population-based studies strongly indicate that chronic exposure to airborne PM, especially combustion-derived PM2.5, accelerates skin aging and thus reduces the quality of life of those affected. There is increasing evidence that especially PM-bound polycyclic aromatic hydrocarbons (PAHs) critically contribute to the clinical manifestation of skin aging, i.e. the development of lentigines/pigment spots and coarse wrinkles. PAHs harm human skin primarily by activating the aryl hydrocarbon receptor (AHR), a ligand-activated transcription factor amongst others involved in orchestrating xenobiotic metabolism and immune responses. In this review, we summarize the available population-based data linking particulate air pollution exposure to skin aging. We explain in detail how PAH-rich PM induces the formation of oxidative stress, the release of pro-inflammatory mediators, the expression extracellular matrix degrading metalloproteases, and melanin synthesis, in an AHR-dependent manner, and how these events may culminate in the development of pigment spots and wrinkles, respectively. We also review the current data on the interaction of airborne PM with another factor of the skin aging exposome that exerts its deleterious effects in part through AHR-dependent signaling pathways, namely solar ultraviolet radiation.

The innate immune signaling network follows a canonical format for signal transmission. The innate immune pathway is crucial for defense against pathogens, yet its mechanistic crosstalk with aging processes remains largely unexplored. Retinoic acid-inducible gene-I (RIG-I), a key mediator of antiviral immunity within this pathway, has an enigmatic role in stem cell senescence. Our study reveals that RIG-I levels increase in human genetic and physiological cellular aging models, and its accumulation drives cellular senescence. Conversely, CRISPR/Cas9-mediated RIG-I deletion or pharmacological inhibition in human mesenchymal stem cells (hMSCs) confers resistance to senescence. Mechanistically, RIG-I binds to endogenous mRNAs, with CDKN1A mRNA being a prominent target. Specifically, RIG-I stabilizes CDKN1A mRNA, resulting in elevated CDKN1A transcript levels and increased p21Cip1 protein expression, which precipitates senescence. Collectively, our findings establish RIG-I as a post-transcriptional regulator of senescence and suggest potential targets for the mitigation of aging-related diseases.

Age-related cognitive decline and neuroinflammation are significant contributors to neurodegenerative diseases. In Traditional Chinese Medicine, aging is often associated with "kidney deficiency," a concept linked to impaired bone marrow production and brain function. Epimedii Folium and Curculiginis Rhizoma (XY), a classic herbal pair used to tonify the kidney, are traditionally employed to enhance vitality, bone health, and cognitive function. While previous studies suggest XY's efficacy in pathological models, its impact on natural aging process requires further investigation.

This study aimed to investigate the neuroprotective effects of XY against cognitive impairment and neuroinflammation in naturally aged mice and to explore the underlying mechanisms.

Network pharmacology was used to identify potential targets and pathways, while molecular docking assessed the binding interactions between active compounds from XY and key target proteins. Naturally aged mice were orally treated with XY (2.34, 4.68 g/kg/day) for 26 days. Cognitive function was assessed using behavioral tests. Histological analysis, ELISA, real-time PCR, and Western blotting were employed to evaluate hippocampal neuronal damage, inflammatory markers, senescence-related proteins, and NLRP3 inflammasome components.

Network pharmacology identified key targets and pathways associated with aging and neuroinflammation. Molecular docking confirmed strong binding affinities between active components (e.g., Icariin, Epimedin B, Epimedin C) and relevant protein targets. In vivo, XY treatment significantly improved cognitive performance, ameliorated hippocampal neuronal damage, and suppressed microglial activation in aged mice. Furthermore, XY downregulated the expression of senescence markers (p53, p21, p16, CDK6), pro-inflammatory cytokines (IL-1β, TNF-α, IL-6, IFN-γ), factors associated with the senescence-associated secretory phenotype (SASP), and key components indicative of NLRP3 inflammasome activation (ASC, Caspase-1, IL-1β).

XY alleviates age-related cognitive decline and neuroinflammation in naturally aged mice. These beneficial effects are mediated, at least in part, by reducing inflammatory mediators, modulating microglial activation, attenuating cellular senescence pathways, and suppressing NLRP3 inflammasome activity. These findings highlight the therapeutic potential of XY for managing age-related cognitive impairment and associated neuroinflammation.

The aging vasculature is characterized by endothelial dysfunction, arterial stiffness, and increased susceptibility to vascular pathologies. Central to these changes is the process of cellular senescence, where endothelial and vascular smooth muscle cells lose their replicative and functional capacity and adopt a pro-inflammatory secretory phenotype. This review provides an overview of the key mechanisms underlying vascular senescence, including the p53/p21 and p16/Rb pathways, the senescence-associated secretory phenotype (SASP), and oxidative stress, examines its contribution to cardiovascular diseases in older adults, and highlights emerging therapeutic strategies aimed at delaying or reversing these age-related vascular changes. In vascular cells, DNA damage, oxidative stress, and chronic inflammation associated with aging converge to amplify senescence. Clinically, vascular senescence is linked with hypertension, atherosclerosis, and increased overall cardiovascular risk. Several interventions, ranging from senolytics to lifestyle factors, show promise in mitigating these changes; however, long-term studies are needed. Given that vascular senescence is a pivotal driver of cardiovascular pathology in aging, targeting senescent cells or their secretory phenotype may potentially offer new avenues for preventing or attenuating age-related vascular diseases. This review presents an updated and integrative overview of vascular senescence, connecting fundamental cellular mechanisms with their clinical manifestations and highlighting the most promising therapeutic interventions.

Aging processes underlie common chronic cardiometabolic diseases such as heart failure and diabetes. Cross-organ/tissue interactions can accelerate aging through cellular senescence, tissue wasting, accelerated atherosclerosis, increased vascular stiffness, and reduction in blood flow, leading to organ remodeling and premature failure. This interorgan/tissue crosstalk can accelerate aging-related dysfunction through inflammation, senescence-associated secretome, and metabolic and mitochondrial changes resulting in increased oxidative stress, microvascular dysfunction, cellular reprogramming, and tissue fibrosis. This may also underscore the rising incidence and co-occurrence of multiorgan dysfunction in cardiometabolic aging in the population. Examples include interactions between the heart and the lungs, kidneys, liver, muscles, and brain, among others. However, this phenomenon can also present new translational opportunities for identifying diagnostic biomarkers to define early risks of multiorgan dysfunction, gain mechanistic insights, and help to design precision-directed therapeutic interventions. Indeed, this opens new opportunities for therapeutic development in targeting multiple organs simultaneously to disrupt the crosstalk-driven process of mutual disease acceleration. New therapeutic targets could provide synergistic benefits across multiple organ systems in the same at-risk patient. Ultimately, these approaches may together slow the aging process itself throughout the body. In the future, with patient-centered multisystem coordinated approaches, we can initiate a new paradigm of multiorgan early risk prediction and tailored intervention. With emerging tools including artificial intelligence-assisted risk profiling and novel preventive strategies (eg, RNA-based therapeutics), we may be able to mitigate multiorgan cardiometabolic dysfunction much earlier and, perhaps, even slow the aging process itself.

Despite not proliferating, senescent cells remain metabolically active to maintain the senescence program. However, the mechanisms behind this metabolic reprogramming are not well understood. We identify senescence-induced long noncoding RNA (sin-lncRNA), a previously uncharacterized long noncoding RNA (lncRNA), a key player in this response. While strongly activated in senescence by C/EBPβ, sin-lncRNA loss reinforces the senescence program by altering oxidative phosphorylation and rewiring mitochondrial metabolism. By interacting with dihydrolipoamide S-succinyltransferase (DLST), it facilitates its mitochondrial localization. Depletion of sin-lncRNA causes DLST nuclear translocation, leading to transcriptional changes in oxidative phosphorylation (OXPHOS) genes. While not expressed in highly proliferative cancer cells, it is strongly induced upon cisplatin-induced senescence. Depletion of sin-lncRNA in ovarian cancer cells reduces oxygen consumption and increases extracellular acidification, sensitizing cells to cisplatin treatment. Altogether, these results indicate that sin-lncRNA is specifically induced in senescence to maintain metabolic homeostasis, unveiling an RNA-dependent metabolic rewiring specific to senescent cells.

Senescence is a key cellular response to ionizing radiation. Senescent cells experience irreversible growth arrest while remaining metabolically active and secrete a distinct set of proteins, collectively referred to as the senescence-associated secretory phenotype (SASP). These secreted factors influence neighboring non-irradiated cells through a mechanism known as the bystander effect. This study aimed to investigate and characterize the bystander effect in a melanoma cell model.

Murine melanoma B16F0 cells were exposed to X-irradiation (10 Gy), and senescence was induced 3 days later. Conditioned media from the senescent cells was collected and used to culture non-irradiated B16F0 cells. Proliferation, viability, clonogenic capacity, DNA damage foci formation, apoptosis, and senescence were assessed. The composition of the senescence-associated secretory phenotype was analyzed using mass spectrometry and bioinformatics tools.

Conditioned media from senescent cells induced by radiation reduced growth and promoted senescence in tumor cell cultures not exposed to ionizing radiation. Mass spectrometry analysis revealed greater protein diversity and abundance in conditioned media from senescent cells compared to that from non-irradiated cells. Additionally, conditioned media from senescent cells contained higher concentrations of proteins related to immune response, cellular aging, and responses to oxidative stress.

Cells undergoing radiation-induced senescence promote bystander senescence by secreting soluble factors involved in the induction and maintenance of senescence.

A detailed understanding of aging biology and the development of anti-aging therapeutic strategies remain imperative yet inherently challenging due to the protracted nature of aging. Cellular senescence arises naturally through replicative exhaustion and is accelerated by clinical treatments or environmental stressors. The accumulation of senescent cells-defined by a loss of mitogenic potential, resistance to apoptosis, and acquisition of a pro-inflammatory secretory phenotype-has been implicated as a key driver of chronic disease, tissue degeneration, and organismal aging. Recent studies have highlighted the therapeutic promise of senolytic drugs, which selectively eliminate senescent cells. Compelling results from preclinical animal studies and ongoing clinical trials underscore this potential. However, the clinical translation of senolytics requires further pharmacological validation to refine selectivity, minimize toxicity, and determine optimal dosing. Equally important is the evaluation of senolytics' potential to restore tissue structure and function by reducing the senescent cell burden. In vitro tissue culture models offer a powerful platform to advance these efforts. This review summarizes the current landscape of in vitro systems used for inducing cellular senescence-referred to as "senescence assays"-and for screening senolytic drugs-referred to as "senolytic assays". We conclude by discussing key challenges to improving mechanistic insight, predictive accuracy, and clinical relevance in senolytic drug development, as well as emerging applications of senolytic therapies.

Replicative senescence occurs in response to shortened telomeres and is triggered by ATM and TP53-mediated DNA damage signaling that blocks replication. hTERT lengthens telomeres, which is thought to block damage signaling and the onset of senescence. We find that normal diploid fibroblasts expressing hTERT mutants unable to maintain telomere length do not initiate DNA damage signaling and continue to replicate, despite having telomeres shorter than senescent cells. The TRF1 and TRF2 DNA binding proteins of the shelterin complex stabilize telomeres, and we find that expression of different mutant hTERT proteins decreases levels of the Siah1 E3 ubiquitin ligase that targets TRF2 to the proteasome, by increasing levels of the CDC20 and FBXO5 E3 ligases that target Siah1. This restores the TRF2:TRF1 ratio to block the activation of ATM and subsequent activation of TP53 that is usually associated with DNA damage-induced senescence signaling. All hTERT variants reduce DNA damage signaling, and this occurs concomitantly with telomeres assuming a more compact, denser conformation than senescent cells as measured by super-resolution microscopy. This indicates that hTERT variants induce TRF2-mediated telomere compaction that is independent of telomere length, and it plays a dominant role in regulating the DNA damage signaling that induces senescence and blocks replication of human fibroblasts. These observations support the idea that very short telomeres often seen in cancer cells may fail to induce senescence due to selective stabilization of components of the shelterin complex, increasing telomere density, rather than maintaining telomere length via the reverse transcriptase activity of hTERT.

Cellular senescence is characterized by irreversible cell-cycle exit, a pro-inflammatory secretory phenotype, macromolecular damage, and deregulated metabolism. Senescent cells are highly associated with age-related diseases. We previously demonstrated that targeted elimination of senescent cells prevents neurodegenerative disease in tau (MAPTP301S;PS19) mutant mice. Here, we show that genetic ablation of the senescence mediator p16Ink4a is sufficient to attenuate senescence signatures in PS19 mice. Disease phenotypes-including neuroinflammation, phosphorylated tau, neurodegeneration, and cognitive impairment-were blunted in the absence of p16Ink4a. Additionally, we found that PS19 mouse brains display p16Ink4-dependent neurovascular alterations such as vessel dilation, increased vessel density, deregulated endothelial cell extracellular matrix, and astrocytic endfoot depolarization. Finally, we show that p16Ink4a deletion in endothelial cells and microglia alone attenuates many of the same phenotypes. Altogether, these results indicate that neurodegenerative disease in PS19 mice is driven, at least in part, by p16Ink4a-expressing endothelial cells and microglia.

Cellular senescence is the permanent cessation of cell proliferation and growth. Senescent cells accumulating in tissues and organs with aging contribute to many chronic diseases, mainly through the secretion of a pro-inflammatory senescence-associated secretory phenotype (SASP). Senotherapeutic (senolytic or senomorphic) strategies targeting senescent cells or/and their SASP are being developed to prolong healthy lifespan and treat age-related pathologies. Sodium-glucose co-transporter 2 (SGLT2) inhibitors are a new class of anti-diabetic drugs that promote the renal excretion of glucose, resulting in lower blood glucose levels. Beyond their glucose-lowering effects, SGLT2 inhibitors have demonstrated protective effects against cardiovascular and renal events. Moreover, SGLT2 inhibitors have recently been associated with the inhibition of cell senescence, making them a promising therapeutic approach for targeting senescence and aging. This review examines the latest research on the senotherapeutic potential of SGLT2 inhibitors.

Ginsenoside Rg1 is a key bioactive compound in ginseng, a traditional herbal medicine known for tonifying qi and nourishing blood, traditionally used to replenish "qi" by regulating hematopoietic function. But its underlying mechanism remains to be elucidated.

This study aims to delve into the role of Rg1 on senescent hematopoiesis and its mechanisms.

A model of D-galactose-induced hematopoietic injury was established with ginsenoside Rg1. The hematopoietic supportive effect of Rg1 was assessed by quantifying the levels of hematopoietic supportive factors VCAM1, CXCL12 and SCF, CFU-Mix formation and cellular senescence; and the levels of inflammatory factors and oxidative stress were measured by ELISA in the serum and cellular supernatant of mice. Co-culture technique was used to examine the ability of Rg1 to restore impaired hematopoiesis by improving the inflammatory hematopoietic microenvironment. For mechanism exploration, RNA-Seq was used to detect differential genes in Rg1-treated MSCs, GO- and KEGG-based enrichment analyses were used to screen the key pathways in which Rg1 exerts its effects, and molecular docking was used to demonstrate the feasibility of molecular interconnections between Rg1 and TLR2. To further explore the mechanism, pathway activators were further used and the expression levels of target proteins downstream of the TLR2 pathway were quantified using Western blotting.

Rg1 decreased the levels of inflammatory factors IL-1β, IL-6 and TNFα, while enhancing the expression of hematopoietic support factors in senescent MSCs, thereby improving the self-renewal and differentiation of aged HSPCs. Additionally, Rg1 also delayed HSPC senescence and reduced the level of oxidative stress. KEGG and GO were enriched for the Toll/NF-κB signaling pathway, based on differential genes obtained by transcriptional sequencing. Rg1 could inhibit the elevated levels of MyD88, NF-κB-p65 and IκBα proteins, and their phosphorylation levels by binding to TLR2 protein and inhibiting them. In conclusion, Rg1 ameliorates the inflammatory hematopoietic microenvironment induced by MSCs senescence via the TLR2/NF-κB-p65 signaling pathway, alleviating HSPCs senescence.

Our results reveal the mechanism by which Rg1 regulates HSPCs function and represent a potential therapeutic strategy for hematopoietic dysfunction, highlighting the potential value of traditional Chinese medicine extracts in clinical applications.

Cellular communication network factor 2 (CCN2, also known as CTGF) is a complex protein that regulates numerous cellular functions. This biomolecule exhibits dual functions, depending on the context, and can act as a matricellular protein or as a growth factor. CCN2 is an established marker of fibrosis and a well-known mediator of kidney damage, involved in the regulation of inflammation, extracellular matrix remodeling, cell death, and activation of tubular epithelial cell (TECs) senescence. In response to kidney damage, cellular senescence mechanisms are activated, linked to regeneration failure and progression to fibrosis. Our preclinical studies using a total conditional CCN2 knockout mouse demonstrate that CCN2 plays a significant role in the development of a senescence phenotype after exposure to a nephrotoxic agent. CCN2 induces cell growth arrest in TECs, both in the early phase and in the chronic phase of folic acid nephropathy (FAN), associated with cell-death/necroinflammation and fibrosis, respectively. Renal CCN2 overexpression was found to be linked to excessive collagen accumulation in tubulointerstitial areas, microvascular rarefaction, and a decline in renal function, which were observed three weeks following the initial injury. All these findings were markedly diminished in conditional CCN2 knockout mice. In the FAN model, injured senescent TECs are associated with microvascular rarefaction, and both were modulated by CCN2. In primary cultured endothelial cells, as previously described in TECs, CCN2 directly induced senescence. The findings collectively demonstrate the complexity of CCN2, highlight the pivotal role of cellular senescence as an important mechanism in renal injury, and underscore the critical function of this biomolecule in kidney damage progression.

Diabetes mellitus is one of the risk factors for periodontitis. Patients with diabetes mellitus possess higher prevalence of periodontitis, more severe periodontal destruction, yet the underlying mechanisms of action are not yet clear. Annexin A2 (ANXA2) is a calcium-dependent phospholipid-binding protein widely involved in membrane repair, cytokinesis, and endocytosis. In this study, we explore whether ANXA2 is one of the associative links between diabetes and periodontitis and find out its underlying mechanisms. Cellular senescence and mitochondrial functions (ROS, mitochondrial morphology, mitochondrial autophagy) were observed. We observed that ANXA2 expression was down-regulated in Periodontal ligament cells (PDLCs) under high glucose conditions. Furthermore, overexpression of ANXA2 delayed high glucose-induced cellular senescence and mitochondrial dysfunction. β-galactosidase activity and the mRNA levels of the senescence-relative genes(p21,p16) were decreased, mitochondrial fracture and ROS release were reduced, and the expression of mitochondrial autophagy-related proteins (LC3,p62,Parkin) was enhanced. expression was enhanced. Mechanistically, we demonstrated that it can regulate the AKT/eNOS signaling pathway by knockdown and overexpression of ANXA2 which was measured using Western blotting (WB) assay to measure the expression of eNOS, p-eNOS Ser1177, Akt and p-Akt Ser473 proteins in PDLCs. After that, we used AKT and eNOS inhibitors to demonstrate the protective effect of ANXA2 on PDLCs under high glucose conditions. The above results suggest that ANXA2 has an anti-aging protective effect, attenuates high glucose-induced cellular senescence in PDLCs, and maintains mitochondrial homeostasis. Therefore, it would be valuable to further explore its role in the link between diabetes and periodontitis in future experiments.

Several bat species live >20-40 years, suggesting that they possess efficient anti-aging and anti-cancer defenses. Here we investigate the requirements for malignant transformation in primary fibroblasts from four bat species Myotis lucifugus, Eptesicus fuscus, Eonycteris spelaea, and Artibeus jamaicensis - spanning the bat evolutionary tree and including the longest-lived genera. We show that bat fibroblasts do not undergo replicative senescence, express active telomerase, and show attenuated SIPs with dampened secretory phenotype. Unexpectedly, unlike other long-lived mammals, bat fibroblasts are readily transformed by two oncogenic "hits": inactivation of p53 or pRb and activation of HRASG12V. Bat fibroblasts exhibit increased TP53 and MDM2 transcripts and elevated p53-dependent apoptosis. M. lucifugus shows a genomic duplication of TP53. We hypothesize that some bat species have evolved enhanced p53 activity as an additional anti-cancer strategy, similar to elephants. Further, the absence of unique cell-autonomous tumor suppressive mechanisms may suggest that in vivo bats may rely on enhanced immunosurveillance.

Aging is typically associated with decreased musculoskeletal function, leading to reduced mobility and increased frailty. As a hallmark of aging, cellular senescence plays a crucial role in various age-related musculoskeletal diseases, including osteoporosis, osteoarthritis, intervertebral disc degeneration, and sarcopenia. The detrimental effects of senescence are primarily due to impaired regenerative capacity of stem cells and the pro-inflammatory environment created by accumulated senescent cells. The secreted senescence-associated secretory phenotype (SASP) can induce senescence in neighboring cells, further amplifying senescent signals. Although the removal of senescent cells and the suppression of SASP factors have shown promise in alleviating disease progression and restoring musculoskeletal health in mouse models, clinical trials have yet to demonstrate significant efficacy. This review summarizes the mechanisms of cellular senescence in age-related musculoskeletal diseases and discusses potential therapeutic strategies targeting cellular senescence.

Poly (ADP-ribose) polymerase (PARP) inhibitors have improved the prognosis of homologous recombination deficient (HRD) ovarian cancer (OC), while effective therapeutic strategies for HR-proficient (HRP) OC still need to be established. This study investigates senescence-mediated inflammation as a novel mechanism of action for PARP inhibitors in HRP cancers. Transcriptome analyses were performed in olaparib-treated HeLa cells as a HRP model. Interferon regulatory factor-Lucia luciferase (IRF-Luc) reporter activity was assessed. The effects of PARP inhibitors on senescence-like phenotypes were assessed in seven HRP cancer cell lines, based on morphological changes, senescence-associated β-galactosidase (SA-β-GAL) activity, cellular granularity, and senescence-associated secretory phenotype (SASP)-related gene expression. Peripheral blood mononuclear cell (PBMC) migration assays were also performed with the conditioned medium in treatment with the PARP inhibitor. Transcriptome analyses revealed numbers of inflammatory cytokine- and chemokine-related pathways were significantly upregulated in olaparib-treated HeLa cells, which were confirmed by IRF-Luc reporter assays. The PARP inhibitors induced senescent phenotypes in HRP cancer cell lines: flattened and enlarged morphology, increased SA-β-GAL activity, elevated cellular granularity, and upregulated expressions of SASP-related genes (e.g., IL1B, IL6, and CXCL10). Furthermore, in vitro migration assays revealed that PARP inhibitor-treated HRP cancer cells attracted PBMCs more abundantly, suggesting the potential for recruiting immune cells to HRP cancer cells through senescence-mediated immunological activation. Our findings suggest that PARP inhibitors recruit immune cells to HRP cancer cells, potentially activating immune responses in the tumor microenvironment, providing new insights into the clinical benefits of PARP inhibitors in immunotherapy for patients with HRP OC.

With age, our metabolic systems undergo significant alterations, which can lead to a cascade of adverse effects that are implicated in both metabolic disorders, such as diabetes, and in the body's ability to respond to acute stress and trauma. To elucidate the metabolic imbalances arising from aging, we introduce the concept of "metabolaging." This framework encompasses the broad spectrum of metabolic disruptions associated with the hallmarks of aging, including the functional decline of key metabolically active organs, like the adipose tissue. By examining how these organs interact with essential nutrient-sensing pathways, "metabolaging" provides a more comprehensive view of the systemic metabolic imbalances that occur with age. This concept extends to understanding how age-related metabolic disturbances can influence the response to acute stressors, like burn injuries, highlighting the interplay between metabolic dysfunction and the ability to handle severe physiological challenges. Finally, we propose potential interventions that hold promise in mitigating the effects of metabolaging and its downstream consequences.

The p16/CDKN2A protein is being explored as an independent prognostic marker in laryngeal cancer, with studies suggesting that p16-positive patients may have a better prognosis. While its role is well-established in oropharyngeal squamous cell carcinoma (OPSCC) related to HPV, ongoing research indicates its potential prognostic value in laryngeal cancer, even in HPV-negative cases.

In this study, we investigated the association between survival outcomes and p16 expression in a cohort of 310 laryngeal cancer patients from the Cancer Genome Atlas (TCGA) Program and the University of Maryland Medical Center (UMMC).

In the TCGA cohort, patients with high p16 protein expression had a significantly higher probability of disease-free survival (DFS) at 89%, compared to 51% in the low p16 protein group (p = 0.0266). Additionally, the mean relative p16 protein expression decreased significantly with advancing TNM stage, measured at 1.116 for stage II, 1.075 for stage III, and 0.6204 for stage IV (p = 0.7871 for stage II vs. stage III, p = 0.0065 for stage III vs. stage IV, p = 0.0031 for stage I vs. stage IV). Protein expression for p16 also correlated with CDKN2A retention/deletion status (p = 0.0077), where the DFS was higher in patients with retained CDKN2A than those with deleted CDKN2A (p = 0.0187). Multivariate analysis of the UMMC and TCGA cohorts revealed that both an increase in the patient's age and higher T stage significantly increased the risk of mortality (p = 0.05, p = 0.01, respectively).

While this study observes trends suggesting that low p16 protein expression is associated with longer DFS and advanced TNM stage in laryngeal cancer, the multivariate analysis did not establish p16 as an independent prognostic factor. These findings suggest that while p16 may have a biological role in tumor progression, its utility as a standalone prognostic marker in clinical outcomes requires further validation.

We tested the ability of a single intravitreal injection of foselutoclax (hereafter UBX1325), a novel senolytic small molecule inhibitor of antiapoptotic protein B-cell lymphoma-extra large, to mitigate the impact of diabetic macular edema.

Patients with diabetic macular edema with prior suboptimal response to anti-vascular endothelial growth factor treatment were randomly assigned (1:1) to either a single intravitreal injection of 10 μg of UBX1325 or sham and were followed for up to 48 weeks. The primary trial objective was to evaluate the safety and side-effect profile of UBX1325 as assessed by ocular and systemic treatment-emergent adverse events (TEAEs). Our secondary objective was to probe efficacy, defined as mean changes from baseline for UBX1325 versus sham in best corrected visual acuity measured in Early Treatment of Diabetic Retinopathy Study (ETDRS) letters (range, 0-100 letters, higher scores indicate better vision) and retinal structure.

Between June 2021 and April 2022, 65 participants (32.3% women) were randomly assigned to either UBX1325 (n=32) or sham (n=33). There were four TEAEs of Grade 3 or greater in the sham group, of which three were considered serious, while there were five in the UBX1325 group of Grade 3 or greater and considered serious. There were no apparent between-group differences with respect to vital signs, electrocardiograms, or routine blood chemistries. For the secondary outcome of efficacy, the difference between UBX1325 and sham in mean change to week 48 in best corrected visual acuity was 5.6 more ETDRS letters (95% confidence interval, -1.5 to 12.7).

In this sham-controlled trial there were no TEAEs that led to discontinuation of treatment with UBX1325 compared with sham. There were trends suggestive of potential efficacy; larger trials are needed to further evaluate these findings. (Funded by UNITY Biotechnology; ClinicalTrials.gov number, NCT04857996.).

Immunotherapy has transformed the landscape of cancer treatment, with T cell-based strategies at the forefront of this revolution. However, the durability of these responses is frequently undermined by two intertwined phenomena: T cell exhaustion and senescence. While exhaustion is driven by chronic antigen exposure in the immunosuppressive tumor microenvironment, leading to a reversible state of diminished functionality, senescence reflects a more permanent, age- or stress-induced arrest in cellular proliferation and effector capacity. Together, these processes represent formidable barriers to sustained anti-tumor immunity. In this review, we dissect the molecular underpinnings of T cell exhaustion and senescence, revealing how these dysfunctions synergistically contribute to immune evasion and resistance across a range of solid tumors. We explore cutting-edge therapeutic approaches aimed at rewiring the exhausted and senescent T cell phenotypes. These include advances in immune checkpoint blockade, the engineering of "armored" CAR-T cells, senolytic therapies that selectively eliminate senescent cells, and novel interventions that reinvigorate the immune system's capacity for tumor eradication. By spotlighting emerging strategies that target both exhaustion and senescence, we provide a forward-looking perspective on the potential to harness immune rejuvenation. This comprehensive review outlines the next frontier in cancer immunotherapy: unlocking durable responses by overcoming the immune system's intrinsic aging and exhaustion, ultimately paving the way for transformative therapeutic breakthroughs.

Fruits and vegetables contain biologically active phenolic compounds that show mitigating effects against free radical damage and inflammation. The unique properties of phenolic compounds are protection against oxidative stress, and inception and potentiating of inflammation in the body. Aging is manifest with changes in epigenetic modifications and as with living systems undergo entropy. The gradual decline of body functions and in many cases with aging the cellular processes of senescence are contributors to age-related diseases. Herein the focus is on phenolic compounds as a diet approach to delay the negative consequences of aging. The actions of phenolic compounds on the biology of aging and senescence are presented. The phenolic compounds called flavonoids which are found in many fruits are potential antisenescence factors that benefit health by reducing damage to DNA and the senescence-associated phenotypic cell changes in healthy cells during aging. Flavonoids are proposed to delay and palliate aging where senescence is involved. The dietary sources of natural phenolic compounds afford protection in the aging process and include as some examples naringenin, hesperidin, quercetin, kaempferol, luteolin, genistein, epigallocatechin gallate, and resveratrol. Many of these compounds possess antisenescence effects. The purpose of the review is to discuss where food flavonoids interact with the targets of senescence and how these compounds can attenuate aging-related events. The goal is to provide greater insight into dietary flavonoids and how they improve health and lower the consequences of aging. A novel aspect of this review is the application of flavonoids to neuroprotective effects in brain to reduce pain and improve health with aging.

Cellular senescence is characterized by proliferation arrest and a senescence-associated secretory phenotype (SASP), that plays a role in aging and the progression of various age-related diseases. Although various metabolic alterations have been reported, no consensus exists regarding mitochondrial bioenergetics. Here we compared mitochondrial metabolism of human fibroblasts after inducing senescence with different stimuli: the oxidant hydrogen peroxide (H2O2), the genotoxic doxorubicin, serial passage, or expression of the H-RASG12V oncogene (RAS). In senescence induced by H2O2, doxorubicin or serial passage a decrease in respiratory control ratio (RCR) and coupling efficiency was noted, in relation to control cells. On the contrary, oncogene-induced senescent cells had an overall increase in respiration rates, RCR, spare respiratory capacity and coupling efficiency. In oncogene-induced senescence (OIS) the increase in respiration rates was accompanied by an increase in fatty acid catabolism, AMPK activation, and a persistent DNA damage response (DDR), that were not present in senescent cells induced by either H2O2 or doxorubicin. Inhibition of AMPK reduced mitochondrial oxygen consumption and secretion of proinflammatory cytokines in OIS. Assessment of enzymes involved in acetyl-CoA metabolism in OIS showed a 3- to 7.5-fold increase in pyruvate dehydrogenase complex (PDH), a 40% inhibition of mitochondrial aconitase, increased phosphorylation and activation of ATP-citrate lyase (ACLY), and inhibition of acetyl-CoA carboxylase (ACC). There was also a significant increase in expression and nuclear levels of the deacetylase sirtuin 6 (SIRT6). These changes can influence the sub-cellular distribution of acetyl-CoA and modulate protein acetylation reactions in the cytoplasm and nuclei. In fact, ACLY inhibition reduced histone 3 acetylation (H3K9Ac) in OIS and secretion of SASP components. In summary, our data show marked heterogeneity in mitochondrial energy metabolism of senescent cells, depending on the inducing stimulus, reveal new metabolic features of oncogene-induced senescent cells and identify AMPK and ACLY as potential targets for SASP modulation.

Aging is characterized by a steady loss of physiological integrity, leading to impaired function and increased vulnerability to death. Cell senescence is a biological process that progresses with aging and is believed to be a key driver of age-related diseases. Senescence, a hallmark of aging, also demonstrates its beneficial physiological aspects as an anti-cancer, pro-regenerative, homeostatic, and developmental mechanism. A transitory response in which the senescent cells are quickly formed and cleared may promote tissue regeneration and organismal fitness. At the same time, senescence-related secretory phenotypes associated with extended senescence can have devastating effects. The fact that the interaction between senescent cells and their surroundings is very context-dependent may also help to explain this seemingly opposing pleiotropic function. Further, mitochondrial dysfunction is an often-unappreciated hallmark of cellular senescence and figures prominently in multiple feedback loops that induce and maintain the senescent phenotype. This review summarizes the mechanism of cellular senescence and the significance of acute senescence. We concisely introduced the context-dependent role of senescent cells and SASP, aspects of mitochondrial biology altered in the senescent cells, and their impact on the senescent phenotype. Finally, we conclude with recent therapeutic advancements targeting cellular senescence, focusing on acute injuries and age-associated diseases. Collectively, these insights provide a future roadmap for the role of senescence in organismal fitness and life span extension.

As emerging therapeutic strategies for aging and age-associated diseases, various biochemical approaches have been developed to selectively remove senescent cells, but how physical stimulus influences senescent cells and its possible application in senolytic therapy has not been reported yet. Here we developed a physical method to selectively stimulate senescent cells via low-intensity pulsed ultrasound (LIPUS) treatment. LIPUS stimulation did not affect the cell cycle, but selectively enhanced secretion of specific cytokines in senescent cells, known as the senescence-associated secretory phenotype (SASP), resulting in enhanced migration of monocytes/macrophages and upregulation of phagocytosis of senescent cells by M1 macrophage. We found that LIPUS stimulation selectively perturbed the cellular membrane structure in senescent cells, which led to activation of the intracellular reactive oxygen species-dependent p38-NF-κB signaling pathway. Using a UV-induced skin aging mouse model, we confirmed enhanced macrophage infiltration followed by reduced senescent cells after LIPUS treatment. Due to the advantages of ultrasound treatment, such as non-invasiveness, deep penetration capability, and easy application in clinical settings, we expect that our method can be applied to treat various senescence-associated diseases or combined with other established biochemical therapies to enhance efficacy.

Cellular senescence is a cell fate triggered by stressful stimuli and displays a hypersecretory feature, the senescence-associated secretory phenotype (SASP). Senescent cell burden increases with aging and contributes to age-related organ dysfunction and multiple chronic disorders. In this study, a large scale screening of a natural product library for senotherapeutic candidates is performed. Apigenin, a dietary flavonoid previously reported with antioxidant and anti-inflammatory activities, exhibits capacity for targeting senescent cells as a senomorphic agent. This compound blocks the interactions between ATM/p38MAPK and HSPA8, preventing the transition of an acute stress-associated phenotype (ASAP) toward the SASP. Mechanistically, apigenin targets peroxiredoxin 6 (PRDX6), an intracellular redox-active molecule, suppressing the iPLA2 activity of PRDX6 and disrupting downstream reactions underlying SASP development. Apigenin reduces the severity of cancer cell malignancy promoted by senescent stromal cells in culture, while restraining chemoresistance when combined with chemotherapy in anticancer regimens. In preclinical trials, apigenin improves the physical function of animals with a premature aging-like state, alleviating physical frailty and cognitive impairment. Together, the study demonstrates the feasibility of exploiting a natural compound with senomorphic capacity to achieve geroprotective effects by modulating the SASP, thus providing a baseline for future exploration of natural agents for alleviating age-related conditions.

Cellular senescence contributes to a variety of pathologies associated with aging and is implicated as a cellular state in which cancer cells can survive treatment. Reported senolytic drug treatments act through varying molecular mechanisms, but heterogeneous efficacy across the diverse contexts of cellular senescence indicates a need for predictive biomarkers of senolytic activity. Using multi-parametric analyses of commonly reported molecular features of the senescent phenotype, we assayed a variety of models, including malignant and nonmalignant cells, using several triggers of senescence induction and found little univariate predictive power of these traditional senescence markers to identify senolytic drug sensitivity. We sought to identify novel drug targets in senescent cells that were insensitive to frequently implemented senolytic therapies, such as Navitoclax (ABT-263), using quantitative mass spectrometry to measure changes in the senescent proteome, compared to cells which acquire an acute sensitivity to ABT-263 with senescence induction. Inhibition of the antioxidant GPX4 or the Bcl-2 family member MCL-1 using small molecule compounds in combination with ABT-263 significantly increased the induction of apoptosis in some, but not all, previously insensitive senescent cells. We then asked if we could use BH3 profiling to measure differences in mitochondrial apoptotic priming in these models of cellular senescence and predict sensitivity to the senolytics ABT-263 or the combination of dasatinib and quercetin (D + Q). We found, despite being significantly less primed for apoptosis overall, the dependence of senescent mitochondria on BCL-XL was significantly correlated to senescent cell killing by both ABT-263 and D + Q, despite no significant changes in the gene or protein expression of BCL-XL. However, our data caution against broad classification of drugs as globally senolytic and instead provide impetus for context-specific senolytic targets and propose BH3 profiling as an effective predictive biomarker.

Granulosa cell-produced inflammatory factors may be key contributors to ovarian dysfunction, and Immp2l deficiency accelerates ovarian aging via granulosa cell senescence; however, the role of inflammation in granulosa cell senescence is largely unknown. Therefore, in this study, cGAS-STING-mediated inflammation was explored in Immp2l deficiency-induced granulosa cell senescence. Immp2l deficiency led to senescence-associated secretory phenotype (SASP) and granulosa cell senescence. Immp2l knockout caused mitochondrial dysfunction and mitochondrial DNA (mtDNA) leakage into the cytoplasm. The cytoplasmic mtDNA was recognized by the DNA-sensing molecule cGAS-STING, which activates cGAS-STING and key downstream interferon-stimulated genes (ISGs) and then promotes the secretion of proinflammatory factors, leading to SASP in senescent granulosa cells. Interestingly, the mitochondrial inner membrane pore protein (Cyclophilin D40) CyPD40 and the outer membrane pore protein voltage-dependent-anion channel 1 (VDAC1) were markedly increased in senescent granulosa cells, accompanied by significantly increased expression of the mtDNA stability protein mitochondrial transcription factor A (TFAM). Downregulation of TFAM with siRNA in senescent granulosa cells improved mitochondrial function, significantly decreased mtDNA in the cytoplasm, inhibited the cGAS-STING pathway and markedly decreased CyPD40 and VDAC1 protein levels in TFAM-treated senescent granulosa cells. The SASP phenotype was also alleviated. In addition, senescent granulosa cells were treated with procyanidin B2 (PCB2), which has anti-inflammatory effects, and the TFAM-mediated mtDNA-cGAS-STING pathway was inhibited, accompanied by a markedly reduced SASP phenotype and granulosa cell senescence. In conclusion, Immp2l gene knockout induced granulosa cell senescence by activation of the cGAS-STING pathway via TFAM-mediated mtDNA leakage into the cytoplasm through the CyPD40 and the VDAC1.

Malignant mesothelioma (MM) is a rare but aggressive cancer originating from mesothelial cells, which presents significant challenges to patients' physical and psychological well-being. The gut-lung axis underscores the connection between gut microbiota and respiratory diseases, with emerging evidence suggesting a strong association between gut microbiota and the development of MM. In this study, we conducted a two-sample Mendelian randomization (MR) analysis to investigate the potential causal relationship between gut microbiota and MM, while also exploring the underlying mechanisms through bioinformatics approaches. Gut microbiota summary data were obtained from the MiBioGen consortium, while MM data were sourced from the FinnGen R11 dataset. Causality was examined using the inverse variance weighted method as the primary analysis. Additional methods, including the weighted median, simple mode, MR-Egger, and weighted mode, were also employed. The robustness of the findings was validated through sensitivity analyses, and reverse causality was considered to further strengthen the MR results. Moreover, bioinformatics analyses were conducted on genetic loci associated with both gut microbiota and MM to explore potential underlying mechanisms. Our study suggests that genetically predicted increases in class.Bacilli, family.Rikenellaceae, genus.Clostridium innocuum group, and order.Lactobacillales were suggestively associated with a higher risk of MM, whereas increases in genus.Ruminococcaceae UCG004, genus.Flavonifractor, phylum.Firmicutes, genus.Anaerofilum, genus.Clostridium sensu stricto 1, and genus.Lactobacillus appeared to confer protective effects. Bioinformatics analysis indicated that differentially expressed genes near loci associated with gut microbiota might affect MM by modulating pathways and the tumor microenvironment. The results of this study point to a potential genetic predisposition linking gut microbiota to MM. Further experimental validation is crucial to confirm these candidate microbes, establish causality, and elucidate the underlying mechanisms.

The matricellular protein CYR61/CCN1 is a member of the CCN protein family that plays significant roles in a broad range of physiological processes, including development, tissue repair, and inflammation, among others. CCN1 is also implicated in pathological conditions such as cancer and fibrosis. The diverse functions of CCN1 arise from its ability to bind different receptors located on many cell types, thereby activating diverse signaling pathways. The diverse, yet contradictory, functions mediated by CCN1 makes it a compelling target for investigation, as it offers the prospect of understanding fundamental cellular topics and their possible implications in various diseases. Recently, new cellular functions were attributed to CCN1, including senescence, pro-/anti- fibrosis, and rejuvenation. In this review, we discuss all these new findings along with the basic knowledge about CCN1 to provide an overall understanding of its conflicting roles and their potential corresponding mechanisms of action.

Current antiretroviral therapy (ART) for HIV infection reduces plasma viral loads to undetectable levels and has increased the life expectancy of people with HIV (PWH). However, this increased lifespan is accompanied by signs of accelerated aging and a higher prevalence of age-related comorbidities. Tat (Trans-Activator of Transcription) is a key protein for viral replication and pathogenesis. Tat is encoded by 2 exons, with the full-length Tat ranging from 86 to 101 aa (Tat101). Introducing a stop codon in position 73 generates a 1 exon, synthetic 72aa Tat (Tat72). Intracellular, full-length Tat activates the NF-κB pro-inflammatory pathway and increases antiapoptotic signals and ROS generation. These effects may initiate a cellular senescence program, characterized by cell cycle arrest, altered cell metabolism, and increased senescence-associated secretory phenotype (SASP) mediator release However, the precise role of HIV-Tat in inducing a cellular senescence program in CD4+ T-cells is currently unknown.

Jurkat Tetoff cell lines stably transfected with Tat72, Tat101, or an empty vector were used. Flow cytometry and RT-qPCR were used to address senescence biomarkers, and 105 mediators were assessed in cell supernatants with an antibody-based membrane array. Key results obtained in Jurkat-Tat cells were addressed in primary, resting CD4+ T-cells by transient electroporation of HIV-Tat-FLAG plasmid DNA.

In the Jurkat cell model, expression of Tat101 increased the levels of the senescence biomarkers BCL-2, CD87, and p21, and increased the release of sCD30, PDGF-AA, and sCD31, among other factors. Tat101 upregulated CD30 and CD31 co-expression in the Jurkat cell surface, distinguishing these cells from Tat72 and Tetoff Jurkats. The percentage of p21+, p16+, and γ-H2AX+ cells were higher in Tat-expressing CD4+ T-cells, detected as a FLAG+ population compared to their FLAG- (Tat negative) counterparts. Increased levels of sCD31 and sCD26 were also detected in electroporated CD4+ T-cell supernatants.

Intracellular, full-length HIV-Tat expression increases several senescence biomarkers in Jurkat and CD4+ T-cells, and SASP/Aging mediators in cell supernatants. Intracellular HIV-Tat may initiate a cellular senescence program, contributing to the premature aging phenotype observed in PWH.