Biology subjects

Chronopoulos, A.

Publications and source records attributed to Chronopoulos, A..

5 recordsLinked to original sources

bioRxiv2026

Engineered extracellular vesicles targeting BACE1 reduces amyloid beta plaque formation in a genetic mouse model of Alzheimer Disease

Alzheimers disease (AD) is a progressive neurodegenerative disorder characterized by the accumulation of amyloid-{beta} (A{beta}) plaques, neurodegeneration, and cognitive decline. {beta}-Site amyloid precursor protein cleaving enzyme 1 (BACE1) catalyzes the rate-limiting step in A{beta} production and remains a therapeutic target for AD. However, effective delivery of RNA therapeutics to the brain remains challenging due to the blood-brain barrier (BBB). Here, we evaluated the feasibility of using clinical-grade mesenchymal stem cell-derived extracellular vesicles (EVs) as systemic carriers for Bace1-targeting small interfering RNA (siRNA) in the 5xFAD mouse model of AD. Engineered EVs crossed the BBB and delivered siRNA cargo to the brain, with uptake observed in both neurons and astrocytes. Systemic therapy with EVs engineered to encapsulate Bace1 siRNA resulted in reduced brain Bace1 protein levels and a decrease in amyloid plaque burden compared with control EVs carrying scrambled siRNA. The reduction was most pronounced in larger, high-intensity plaques, suggesting that Bace1 suppression may preferentially limit plaque growth and maturation. Repeated systemic administration was well tolerated, with no evidence of treatment-associated toxicity. These findings establish a proof-of-concept feasibility for EV-mediated delivery of Bace1-targeting siRNA to the brain and support further development of engineered EVs as a therapeutic platform for neurodegenerative diseases. Future studies incorporating behavioral, molecular, and mechanistic analyses will be required to determine the extent to which Bace1 suppression delivered through EVs can modify disease progression and improve functional outcomes in AD.

cell biology↗

bioRxiv2026

Hyaluronan and CD44 targeting reverses early matrix changes, proinflammatory signals and fibrosis in primary sclerosing cholangitis

Primary sclerosing cholangitis (PSC) is a rare, progressive liver disease characterized by biliary inflammation and bile duct strictures and no approved medical therapy. Despite its clinical severity, the pathological mechanisms underlying PSC remain poorly understood, largely due to early diagnostic challenges. Here we provide complementary evidence in human PSC samples, transcriptomic data, mouse models, and 3D cholangiocyte cultures that underscore the importance of hyaluronic acid (HA) and its cognate receptor CD44 in PSC pathogenesis. HA is a glycosaminoglycan abundant in the extracellular matrix in inflammatory disorders, yet its role in PSC has not been well characterized. We demonstrate that in early-stage PSC, cholangiocytes aberrantly produce high molecular weight HA that accumulates in the peribiliary matrix, increasing local tissue stiffness. This mechanical signal is transduced by a CD44/Integrin {beta}1 receptor complex in cholangiocytes, driving cell proliferation, YAP mechanosignaling, pro-inflammatory cytokine production with a transition to a ductular reactive phenotype. CD44 knockdown in cholangiocyte cell lines and mouse models significantly lowered stiffness, and attenuated inflammation. Together, these findings reveal a mechano-inflammatory axis in which HA-driven matrix stiffening perpetuates biliary inflammation and disease progression, identifying HA targeting and CD44 as promising therapeutic strategies. One Sentence SummaryHyaluronan and CD44 mediate matrix changes and progressive fibrosis in primary sclerosing cholangitis.

pathology↗

bioRxiv2024

Differential cell-ECM interaction of rhabdomyosarcoma subtypes regulated by PAX3-FOXO1

Rhabdomyosarcoma (RMS) is the most common childhood soft tissue sarcoma, with two subtypes: Fusion-positive RMS (FPRMS), which has the PAX3-FOXO1 fusion gene, and fusion-negative RMS (FNRMS). Despite their distinct characteristics, treatments mainly rely on conventional chemotherapies without considering these differences. This study highlights that FNRMS cells exhibit significantly heightened interaction with the extracellular matrix (ECM) compared to FPRMS cells. Using single-cell RNA sequencing of skeletal muscle tissues and RNA sequencing of RMS samples, we identified the upregulation of genes related to cell-ECM interaction and TGF{beta} signaling in FNRMS compared to FPRMS. We also confirmed enhanced cell-ECM interaction stimulated by TGF{beta} signaling in FNRMS cells, using confocal reflection microscopy to monitor dynamic cell-ECM interaction and a live-cell sensor to quantitatively assess TGF{beta} signaling activity. Additionally, we discovered that the PAX3-FOXO1 fusion gene, characteristic of FPRMS, stimulated nitric oxide synthesis, which suppresses TGF{beta} signaling and reduces cell-ECM interaction. These findings suggest that PAX3-FOXO1 determines the diminished cell-ECM interactions in FPRMS. Experimental data show higher sensitivity of FNRMS to cell-ECM interaction disruption and TGF{beta} inhibition. Furthermore, the diminished cell-ECM interaction in FPRMS, allowing cells to survive in the ectopic environment through circulation, may partly explain its higher metastatic potential compared to FNRMS.

cell biology↗

bioRxiv2023

Extracellular matrix topography drives adrenergic to mesenchymal transition in neuroblastoma

Neuroblastoma (NB), the most common extracranial solid tumor in children, exhibits significant intra-tumoral heterogeneity with two interconvertible identities: adrenergic (ADRN) and mesenchymal (MES). MES cells exhibit phenotypes associated with metastasis and are enriched in relapse NB compared to ADRN. Thus, reprogramming from ADRN to MES may determine inferior NB outcomes, which needs better elucidation. Extracellular matrix (ECM) is an essential tumor microenvironment (TME) component that provides physical support as a scaffold and delivers mechanical cues. We demonstrate that high-risk NB has more topographically aligned ECM fibers than low-risk NB. Using nano-fabricated biomaterials mimicking ECM alignment, we reveal that ECM topography drives ADRN-MES reprogramming by enhancing cell-ECM interactions. This transition involves epigenetic and transcriptional changes, accompanied by enhanced phenotypic features of MES. Also, we uncover that ECM-driven reprogramming relies on the Rho-associated kinase pathway. Overall, ECM-driven ADRN-MES reprogramming provides insight into TME-targeted therapeutic strategies for suppressing MES and improving NB outcomes.

cell biology↗

bioRxiv2018

SREBP1 drives KRT80-dependent cytoskeletal changes and invasive behavior in endocrine resistant ERα breast cancer

Approximately 30% of women diagnosed with ER breast cancer relapse with metastatic disease following adjuvant treatment with endocrine therapies1,2. The connection between acquisition of drug resistance and invasive potential is poorly understood. In this study, we demonstrate that the type II keratin topological associating domain (TAD)3 undergoes epigenetic reprogramming in cells that develop resistance to aromatase inhibitors (AI), leading to keratin 80 (KRT80) upregulation. In agreement, an increased number of KRT80-positive cells are observed at relapse in vivo while KRT80 expression associates with poor outcome using several clinical endpoints. KRT80 expression is driven by de novo enhancer activation by sterol regulatory element-binding protein 14 (SREBP1). KRT80 upregulation directly promotes cytoskeletal rearrangements at the leading edge, increased focal adhesion maturation and cellular stiffening, which collectively promote cancer cell invasion. Shear-wave elasticity imaging of prospective patients shows that KRT80 levels correlate with stiffer tumors in vivo. Collectively, our data uncover an unpredicted and potentially targetable direct link between epigenetic and cytoskeletal reprogramming promoting cell invasion in response to chronic AI treatment.

cancer biology↗