Biology subjects

Tzioufas, A. G.

Publications and source records attributed to Tzioufas, A. G..

3 recordsLinked to original sources

bioRxiv2025

Salivary Extracellular Vesicle RNA Profiling Reveals Biomarkers for Sjogrens

Sjogrens is a chronic autoimmune disease affecting exocrine glands and is subclassified into SSA-positive (SSA+) and SSA-negative (SSA-) subtypes, with a complex diagnostic journey and an average diagnostic delay of almost 4 years. While SSA+ cases can be detected via serological testing, current assays lack specificity. For SSA-patients, no non-invasive diagnostic tools exist, and diagnosis often requires invasive lip biopsy. A saliva-based liquid biopsy capable of diagnosing both subtypes is therefore of high clinical interest. However, saliva poses challenges due to its abundant oral microbiome, which complicates unbiased biomarker discovery. In this study, we present a novel RNA sequencing workflow that efficiently depletes microbial content, enabling deep profiling of long RNAs within salivary extracellular vesicles (EVs). This approach identified both known and novel RNA biomarkers capable of diagnosing SSA+ and SSA-subtypes with high sensitivity and specificity. Moreover, we uncovered distinct RNA signatures that allow molecular stratification of Sjogrens subtypes. Pathway analysis in SSA+ cases revealed enrichment of immune and glandular pathways consistent with prior tissue-based studies, supporting the utility of salivary EVs as a non-invasive surrogate for tissue biopsy. Importantly, our data provides new molecular insights into the under-characterized SSA-subtype, laying the foundation for future mechanistic studies and facilitating their broader inclusion in clinical trials.

genomics↗

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↗

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↗