Biology subjects

Veroutis, D.

Publications and source records attributed to Veroutis, D..

5 recordsLinked to original sources

bioRxiv2025

Immune cell senescence drives responsiveness to immunotherapy in melanoma

AbstractBackground: Immunotherapy has significantly improved cancer treatment. However, it is not effective in all cancer patients, rendering the need to further delineate the differences among responders and non-responders at the molecular and cellular level. Unresponsiveness to immunotherapy has been attributed to dysfunctional immune cell states such as T-cell exhaustion and anergy, whereas the contribution of cellular senescence remains elusive. Herein, we have investigated the role of immune cell senescence in the response to checkpoint inhibitors in melanomas where these immunotherapies are applied as a first line treatment. Methods: Two senescence detecting complementary approaches were utilized in a case control study we conducted. First, we implemented a senescence molecular signature we developed, termed "SeneVick" retrospectively in a single cell RNA-seq dataset from melanoma patients who received immunotherapy. Prior to this analysis, the signature was extensively validated in a variety of cell/tissue contexts, senescence types and species. Second, cellular senescence was assessed via an established experimental algorithmic approach in circulating immune cells of an analogous melanoma clinical cohort. Results: Melanoma patients who did not respond to immunotherapy exhibited increased cellular senescence in their CD8+ T-cells, CD4+ T-cells, B-cells and NK cells compared to responders. This phenomenon was independent of patients age and not an outcome of immunotherapy, in contrast to conventional anti-cancer treatments. Interestingly, alterations of cell-cell interactions among the immune sub-populations in non-responders compared to responders were identified, suggesting the involvement of immune cell senescence in defective immune responses and treatment failure. Conclusion: Overall, our findings support cellular senescence of the immune cell compartment within the TME, as a potent determinant of the response to immunotherapy and pave the way for strategies targeting immune cell senescence, as promising approaches to improve the outcome of such interventions.

immunology↗

bioRxiv2024

Exercise alleviates liver senescence but does not outmatch the effect of dietary restriction in diet-induced MASLD

BackgroundThe present study aims at deciphering the potential benefits of aerobic exercise and dietary restriction on liver senescence, which is an established hallmark of metabolic dysfunction-associated steatotic liver disease (MASLD), a condition with limited therapeutic options. MethodsC57BL6 mice were subjected to normal diet (ND, 10% of kilocalories from fat) or a high-fat diet (HFD, 60% of kilocalories deriving from fat and water supplemented with 5% High-fructose Corn Syrup, HFCS) for 12 weeks. Then, for additional 8 weeks, the ND group continued with the same diet, while the HFD group was divided into four subgroups: a) mice that continued with the same HFD-5% HFCS in water scheme (HFD), b) mice that continued with the same HFD-5% HFCS in water scheme and underwent supervised aerobic exercise 3-times/week (HFDEX), c) mice that were switched to ND (dietary restriction, DR) and d) mice that were switched to ND while undergoing supervised aerobic exercise 3-times/week (DREX). Phenotypic and histological characterization of obesity and MASLD were performed in all groups. Biomarkers of senescence were analyzed in terms of their mRNA expression levels to assess the impact of all interventions on MASLD-related senescence in the liver. GL13 and p21 immunohistochemical stainings were conducted to examine the protein levels of senescence-associated lipofuscin and p21WAF1/CIP1 respectively, so as to finally investigate their relationship with the grade of steatosis observed in each individual animal. ResultsDR and DREX groups exhibited significantly reduced features of obesity and MASLD-related hepatic steatosis, to a greater extent than the respective amelioration driven by aerobic exercise-only in HFDEX animals. A statistically significant increase of the mRNA expression of cyclin-dependent kinase p21WAF1/CIP1 was detected in HFD livers as compared to ND, which was also reversed upon DR-inclusive interventions. In contrast, the gene expression levels of cyclin-dependent kinase p16INK4a remained similar in all groups even after a combined intervention. Increased hepatic expression of the p27 and p53 components of the p53-p21 CIP/WAF-driven axis of cellular senescence as well as their restoration to ND-like levels upon DR and DREX, suggest an active participation of the p21WAF1/CIP1 mechanism of senescence in the emergence of MASLD, but also in its reversal through DR or/and EX interventions. Immunohistochemical stainings for GL13 and p21 confirmed the aforementioned alterations of p21WAF1/CIP1 at the tissular level. ConclusionLiver senescence is responsive both to exercise and dietary restriction, but its amelioration in the context of MASLD is more robust upon DR-inclusive interventions.

physiology↗

bioRxiv2023

Senescent cells in Giant Cell Arteritis have inflammatory phenotype participating in tissue injury via IL-6 dependent pathways

ObjectivesAge is the strongest risk factor of Giant Cell Arteritis (GCA), implying a possible pathogenetic role of cellular senescence. To address this question, we applied an established senescence specific multi-marker algorithm in tissue artery biopsies (TABs) of GCA patients. MethodsSeventy five positive TABs from GCA patients and 22 negative from patients with Polymyalgia Rheumatica (PMR) were retrospectively retrieved and analyzed. Senescent cells and their histologic origin were identified with specific cellular markers; IL-6 and MMP-9 were investigated as components of the senescent associated secretory phenotype (SASP) by triple co-staining. GCA or PMR artery culture supernatants were applied to primary skin fibroblasts with or without IL-6 blocking agent to explore the induction of IL-6 associated cellular senescence. ResultsSenescent cells were mainly present in GCA arteries at higher proportion compared to PMR (9.50% vs 2.66% respectively, p<0.0001) and were mainly originated from fibroblasts, macrophages and endothelial cells. IL-6 was expressed by senescent fibroblasts and macrophages while MMP-9 by fibroblasts only. IL-6 positive senescent cells were associated with the extension of vascular inflammation (adventitial limited disease vs transmural inflammation: 10.02% vs 4.37% respectively, p<0.0001). GCA but not PMR artery culture supernatant could induce IL-6-associated senescence that was partially inhibited by IL-6 blockade. ConclusionsSenescent cells with inflammatory phenotype are present in GCA arteries and are associated with the tissue inflammatory bulk. These findings might suggest a potential implication in disease pathogenesis by perpetuating inflammation and affecting vascular remodeling via IL-6 dependent mechanisms.

cell biology↗

bioRxiv2022

A tumour-promoting senescent secretome triggered by platinum chemotherapy exploits a targetable TGFβR1/Akt-mTOR axis in lung cancer

Platinum-based chemotherapy is commonly used for non-small cell lung cancer (NSCLC) treatment, yet clinical outcomes remain poor. Cellular senescence and its associated secretory phenotype (SASP) can have multiple tumour-promoting activities, although these are largely unexplored in lung cancer. Here we show that cisplatin-derived SASP enhances the malignant phenotype of lung cancer cells. Using xenograft, orthotopic and KrasG12V-driven murine NSCLC models, we demonstrate that cisplatin-induced senescent cells strongly promote tumour progression. Mechanistically, we find that a TGF-{beta}-enriched SASP drives pro-proliferative effects through TGF{beta}R1 and Akt/mTOR pathway activation. We validate the translational relevance of chemotherapy-induced SASP using clinical NSCLC samples from patients who received neoadjuvant platinum-based chemotherapy. Importantly, TGF{beta}R1 inhibition with galunisertib or senolytic treatment significantly reduces tumour promotion driven by cisplatin-induced senescence. Finally, we demonstrate, using distinct murine NSCLC models, that addition of TGFBR1 inhibitors to platinum-based chemotherapy reduces tumour burden and improves survival, providing pre-clinical proof-of-concept for future trial designs.

cancer biology↗

bioRxiv2021

Alveolar type II cells harbouring SARS-CoV-2 show senescence with a proinflammatory phenotype

RationaleSARS-CoV-2 infection of the respiratory system can progress to a life threatening multi-systemic disease, mediated via an excess of cytokines ("cytokine storm"), but the molecular mechanisms are poorly understood. ObjectivesTo investigate whether SARS-CoV-2 may induce cellular senescence in lung epithelial cells, leading to secretion of inflammatory cytokines, known as the senescence-associated secretory phenotype (SASP). MethodsAutopsy lung tissue samples from eleven COVID-19 patients and sixty age-matched non-infected controls were analysed by immunohistochemistry for SARS-CoV-2 and markers of cellular senescence (SenTraGor, p16INK4A) and key SASP cytokines (interleukin-1{beta}, interleukin-6). We also investigated whether SARS-CoV-2 infection of an epithelial cell line induces senescence and cytokine secretion. Measurements and Main ResultsSARS-CoV-2 was detected by immunocytochemistry and electron microscopy predominantly in alveolar type-2 (AT2) cells, which also expressed the angiotensin-converting-enzyme 2 (ACE2), a critical entry receptor for this virus. In COVID-19 samples, AT2 cells displayed increased markers of senescence [p16INK4A, SenTraGor staining positivity in 12{+/-}1.2% of cells compared to 1.7{+/-}0.13% in non-infected controls (p<0.001)], with markedly increased expression of interleukin-1{beta} and interleukin-6 (p<0.001). Infection of epithelial cells (Vero E6) with SARS-CoV-2 in-vitro induced senescence and DNA damage (increased SenTraGor and {gamma}-H2AX), and reduced proliferation (Ki67) compared to uninfected control cells (p<0.01). ConclusionsWe demonstrate that in severe COVID-19 patients, AT2 cells are infected with SARS-CoV-2 and show senescence and expression of proinflammatory cytokines. We also show that SARS-CoV-2 infection of epithelial cells may induce senescence and inflammation, indicating that cellular senescence may be an important molecular mechanism of severe COVID-19.

cell biology↗