Biology subjects

Tsiani, E. L.

Publications and source records attributed to Tsiani, E. L..

5 recordsLinked to original sources

bioRxiv2026

Oxidative Stress-Induced Immunogenic Cell Death Enhances Whole-Cell Vaccine Efficacy in a Syngeneic Pancreatic Cancer Model

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive cancer, with limited therapeutic options and extremely high mortality rates. While immune checkpoint blockade (ICB) therapy is effective in many types of human cancers, responses in PDAC patients remain poor, partly due to the weak immunogenicity of PDAC tumors. We hypothesized that a whole-cell PDAC vaccine could improve anti-tumor responses if optimized to expose a more stimulatory repertoire of tumor antigens. To test this, we used murine Panc02 pancreatic cancer cells to screen several stress-inducing treatments (UV, hypoxia, heat shock, and hydrogen peroxide [H2O2]), among which low-dose oxidative stress (0.05% H2O2 for 2h) was identified as the optimal inducer of immunogenic cell death (including increased surface calreticulin, ERp57 exposure, HMGB1 release and MHC class I expression). We then prepared a whole-cell vaccine of fixed H2O2-treated Panc02 cells, which induced robust tumor-specific immunity in C57BL/6 mice bearing syngeneic Panc02 tumors. Vaccine-treated mice displayed a significant increase in tumor-reactive IFN{gamma}+ T cells, as well as extensive tumor infiltration by CD4 + and CD8 + T cells and NCR1+ NK cells. When used prophylactically, the vaccine significantly delayed tumor growth and extended survival, whereas therapeutic application markedly slowed tumor progression. Importantly, combining the whole-cell Panc02 vaccine with anti-PD-1 therapy induced complete tumor regression in a subset of animals. Together, these data demonstrate that controlled oxidative stress can convert autologous tumor cells into an effective whole-cell vaccine without the need for genetic modification or prior neoantigen identification, offering a scalable strategy for personalized immunotherapy in PDAC. STATEMENT OF SIGNIFICANCEThis study demonstrated that oxidative stress-induced immunogenic cell death reprograms pancreatic tumor cells to induce danger signaling and enhance antigen presentation, thereby promoting immune infiltration and sensitizing tumors to PD-1 blockade.

cancer biology↗

bioRxiv2025

IsoDGR-Induced Endothelial Cytoskeletal Disruption Drives Age-Related Blood-Brain Barrier Breakdown

Brain aging is characterized by progressive breakdown of the blood-brain barrier (BBB), which correlates with neuroinflammation and cognitive decline. Emerging evidence implicates degenerative modifications of the vascular proteins as a key driver of BBB dysfunction. In particular, spontaneous deamidation of Asp-Gly-Arg (NGR) motifs generates isoAsp-Gly-Arg (isoDGR) sequences that structurally mimic canonical Arg-Gly-Asp (RGD) integrin-binding ligands. Here, we show that age-associated accumulation of isoDGR in the brain cortex induces endothelial cytoskeletal collapse and tight junction disorganization, leading to BBB breakdown. Using mice lacking the L-isoaspartyl repair enzyme PCMT1 (which accelerates isoDGR accumulation) and wild type aged mice, we found markedly elevated isoDGR in brain tissues accompanied by focal microhemorrhages and increased BBB permeability. Recent whole-genome sequencing suggests that a common PCMT1 variant is linked to neurodegenerative disease risk, indicating potential clinical relevance in vascular aging. Remarkably, systemic treatment with an isoDGR-neutralizing antibody largely prevented capillary breaches and leakage, and even restored barrier integrity in aged wild-type mice. To uncover the molecular mechanism, we exposed brain endothelial cells to synthetic isoDGR-peptides, which recapitulated these effects. Unbiased RNA-sequencing reinforced these findings, revealing broad transcriptomic reprogramming of cytoskeletal, cell-cell junction, inflammatory, and stress-response pathways. Functional studies demonstrated that isoDGR triggered collapse of F-actin stress fibers, disrupted junctional ZO-1 and VE-cadherin, increased monolayer permeability to macromolecules, and impaired endothelial cell migration and proliferation. IsoDGR-treated endothelial cells exhibited increased oxidative stress, upregulation of ICAM-1/VCAM-1/CCL-2, and adopted a senescent phenotype. Our results suggest that isoDGR hijacks endothelial integrin signaling to destabilize the actin cytoskeleton and tight junctions, a process that breaches the BBB and subsequently activates inflammatory and senescence programs. In summary, we identify BBB disruption via isoDGR-induced cytoskeletal dysfunction as a central pathology of vascular aging, and demonstrate that targeting isoDGR damage preserves BBB integrity and attenuates neuroinflammation.

neuroscience↗

bioRxiv2025

Anti-isoDGR Antibody Inhibits Atherosclerosis Induced by Western Diet in ApoE-/- mice

BackgroundDegenerative protein modifications (DPMs) accumulate with aging and can alter biomolecule structure and function, including via spontaneous conversion of Asn-Gly-Arg (NGR) to isoAsp-Gly-Arg (isoDGR) motifs that can bind integrins and drive chronic inflammation. Since isoDGR-modified extracellular matrix proteins are enriched in atherosclerosis and have been associated with rupture-prone plaque characteristics, we hypothesized that antibody neutralisation can inhibit key pathological features including atherosclerotic vascular plaque formation and metabolic dysfunction. MethodsWe first examined Pcmt1-/- mice which rapidly accumulate isoDGR due to lack of the corresponding repair enzyme to assess the extent of vascular protein damage. We then treated 6-8 week old atherosclerosis-prone (ApoE-/-) mice which were fed a high-fat Western diet (WD) with weekly dose of 1mg/kg isoDGR-specific monoclonal antibody (isoDGR-mAb) or isotype-matched control (while on diet) for 2 months duration. A regular chow-fed ApoE-/- group served as baseline control. Aortic atherosclerotic burden, plaque composition, systemic inflammation, lipid profiles, hepatic steatosis, and metabolic parameters (indirect calorimetry) were assessed. ResultsPcmt1-/- mice displayed extensive isoDGR deposition and degeneration of the aortic wall, linking this DPM to vascular structural damage. In the ApoE-/- mice, WD induced large aortic root plaques with abundant isoDGR and macrophage infiltration. IsoDGR-mAb treatment decreased plaque size by [~]30% with reduced lipid and collagen content (p=0.001). Furthermore, plaques in treated mice contained significantly fewer CD68+ macrophages that also exhibited limited activation. Systemically, isoDGR-mAb modified lipoprotein profiles by decreasing atherogenic VLDL/IDL/LDL cholesterol (p=0.04) while slightly increasing HDL, accompanied by a reduction in circulating inflammatory proteins. IsoDGR-mAb also protected against hepatic lipid accumulation which was reduced by [~]60% in treated animals (p<0.001), with indirect calorimetry confirming [~]30% higher oxygen consumption and energy expenditure without change in food intake or physical activity. ConclusionWe identified isoDGR as a key pathological factor involved in the progression of atherosclerosis. Remarkably, isoDGR neutralization diminished plaque inflammation and improved atherosclerotic plaque stability. Our findings support isoDGR neutralization as a promising therapeutic strategy to mitigate both atherosclerosis and aging-associated metabolic dysfunction.

pharmacology and toxicology↗

bioRxiv2023

Age-linked lung pathology is reduced by immunotherapeutic targeting of isoDGR protein damage

Advancing age is the primary risk factor for pulmonary diseases. Our investigation revealed an 8-fold increase in aging induced isoDGR-damaged proteins in lung tissue from human pulmonary fibrosis patients compared to healthy tissues, accompanied by elevated frequencies of CD68+/CD11b+ macrophages, indicating lung tissue is susceptible to time-dependent accumulation of isoDGR-proteins. To elucidate the mechanisms through which isoDGR-proteins may exacerbate aging lung disorders for potential therapeutic targeting, we assessed the functional role of this isoDGR-motif in naturally-aged mice and mice lacking the corresponding isoDGR repair enzyme (Pcmt1-/-). IsoDGR-protein accumulation in mouse lung tissue and blood vessels correlated with chronic low-grade inflammation, pulmonary edema, and hypoxemia. IsoDGR accretion induced mitochondrial and ribosomal dysfunctions, cellular senescence, and apoptosis, contributing to progressive lung damage over time. Treatment with anti-isoDGR antibodies suppressed TLR pathway activity, mitigated cytokine-driven inflammation, restored mtDNA expression, and significantly reduced lung pathology in-vivo. Similarly, exposure of lung endothelial cells to isoDGR-modified fibronectin impaired oxygen consumption, increased reactive oxygen species levels, and disrupted acidification, but these effects were efficiently reversed by target-specific antibody therapy. Collectively, our findings underscore the significant contribution of isoDGR-damaged proteins to age-linked lung pathology. IsoDGR-specific therapy emerges as a promising treatment approach for pulmonary disorders in older patients.

pathology↗

bioRxiv2023

Antibody targeting of aging damaged isoDGR-protein doubles lifespan in a mouse model of chronic inflammation

Aging is the result of the accumulation of molecular damages that impair normal biochemical activities. We previously reported that aging-damaged amino acid sequence NGR (Asn-Gly-Arg) results in a gain-of-function conformational switching to isoDGR (isoAsp-Gly-Arg) motif. This integrin-binding motif activates leukocytes to induce chronic inflammation, which are characteristic features of age-linked cardiovascular disorders. We now report that anti-isoDGR immunotherapy doubles lifespan in mouse model of chronic inflammation. We observed extensive accumulation of isoDGR and inflammatory cytokine expression in multiple tissues from Pcmt1-KO and old WT animals, which could also be induced via injection of isoDGR-modified plasma proteins or synthetic peptides into young WT animals. However, weekly injection of anti-isoDGR mAb (1mg/kg) was sufficient to significantly reduce isoDGR-modified proteins and pro-inflammatory cytokine expression, improve behaviour and coordination, and double the average lifespan of Pcmt1-KO mice. Mechanistically, isoDGR-mAb mediated the immune clearance of damaged isoDGR-proteins by antibody-dependent cellular phagocytosis. These results indicate that immunotherapy targeting aging-damaged proteins may represent effective interventions for a range of age-linked degenerative disorders. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=105 SRC="FIGDIR/small/532237v1_ufig1.gif" ALT="Figure 1"> View larger version (12K): org.highwire.dtl.DTLVardef@81610borg.highwire.dtl.DTLVardef@a22aaorg.highwire.dtl.DTLVardef@169fe50org.highwire.dtl.DTLVardef@1b73d11_HPS_FORMAT_FIGEXP M_FIG Anti-isoDGR immunotherapy induces immune clearance of aging damaged isoDGR-proteins to reduce chronic inflammation, improve behaviour and coordination, and double lifespan in PCMT-/- mice. C_FIG

biochemistry↗