Publications by authors named "Eun-Young Ahn"

Gout is the most common inflammatory arthritis in adults, associated with hyperuricemia and the chronic deposition of monosodium urate (MSU) crystals. Hyperuricemia results from increased production of uric acid and decreased excretion by the kidneys and intestines. Urate excretion is regulated by a group of urate transporters, and decreased renal or intestinal excretion is the primary mechanism of hyperuricemia in most people.

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Atherosclerosis develops at predictable sites in the vasculature where branch points and curvatures create non-laminar disturbed flow. This disturbed flow causes vascular inflammation by increased endothelial cell (EC) barrier permeability and the expression of inflammatory genes such as vascular cell adhesion molecule-1 (VCAM-1). Vascular endothelial growth factor receptor 2 (VEGFR2) is important for flow-induced EC inflammation; however, there are still some gaps in the signaling pathway.

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Epigenetic silencing of tumor suppressor genes is one of the main drivers of tumor progression. Without these tumor suppressors to reduce proliferation, tumor cells proliferate unchecked. Focal adhesion kinase (FAK) is a tyrosine kinase which is often upregulated in various tumors and promotes cell proliferation and migration.

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Background: In breast cancer, ErbB receptors play a critical role, and overcoming drug resistance remains a major challenge in the clinic. However, intricate regulatory mechanisms of ErbB family genes are poorly understood. Here, we demonstrate SON as an ErbB-regulatory splicing factor and a novel therapeutic target for ErbB-positive breast cancer.

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Rare diseases are underrepresented in biomedical research, leading to insufficient awareness. Zhu-Tokita-Takenouchi-Kim (ZTTK) syndrome is a rare disease caused by genetic alterations that result in heterozygous loss of function of SON. While patients with ZTTK syndrome live with numerous symptoms, the lack of model organisms hampers our understanding of SON and this complex syndrome.

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Stem cells regulate their self-renewal and differentiation fate outcomes through both symmetric and asymmetric divisions. mA RNA methylation controls symmetric commitment and inflammation of hematopoietic stem cells (HSCs) through unknown mechanisms. Here, we demonstrate that the nuclear speckle protein SON is an essential mA target required for murine HSC self-renewal, symmetric commitment, and inflammation control.

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Rare diseases are underrepresented in biomedical research, leading to insufficient awareness. Zhu-Tokita-Takenouchi-Kim (ZTTK) syndrome is a rare disease caused by genetic alterations that result in heterozygous loss-of-function of SON. While ZTTK syndrome patients suffer from numerous symptoms, the lack of model organisms hamper our understanding of both SON and this complex syndrome.

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Background And Aims: Hyperlipidemia leads to the accumulation of oxidized low-density lipoprotein (oxLDL) within the vessel wall where it causes chronic inflammation in endothelial cells (ECs) and drives atherosclerotic lesions. Although focal adhesion kinase (FAK) is critical in proinflammatory NF-κB activation in ECs, it is unknown if hyperlipidemia alters FAK-mediated NF-κB activity in vivo to affect atherosclerosis progression.

Methods: We investigated changes in EC FAK and NF-κB activation using Apoe mice fed a western diet (WD).

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Article Synopsis
  • ZTTK syndrome is a neurodevelopmental disorder caused by loss-of-function variants in the SON gene, leading to abnormal RNA splicing and various neurological issues, including seizures and EEG abnormalities.
  • The study involved a patient with ZTTK syndrome who also experienced hemiplegic migraines, enabling researchers to observe the brain's response through MRI and EEG during episodes.
  • Results indicated that knockdown of the SON gene significantly reduced mRNA levels associated with hemiplegic migraine and caused splicing defects that prevented the production of a critical protein, suggesting a possible link between ZTTK syndrome and hemiplegic migraines.
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Article Synopsis
  • This study examines how certain blood ratio markers (NLR, MLR, PLR) relate to treatment responses in ankylosing spondylitis (AS) patients receiving TNF-α blockers.
  • It analyzed data from 279 AS patients and found that those with AS had higher NLR, MLR, and PLR ratios compared to healthy controls, with a low non-response rate within 3 months.
  • Results suggested that a high baseline NLR was linked to a greater risk of treatment non-response and shorter endurance with TNF-α blockers, indicating its potential use as a predictive marker.
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Background and Objectives: We investigated whether nutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphoycte ratio (PLR), and monocyte-to-lymphocyte ratio (MLR) are associated with the presence of osteoporosis (OP) and vertebral fractures in patients with rheumatoid arthritis (RA). Materials and Methods: This retrospective cohort study included 413 postmenopausal patients with RA and 200 healthy controls who underwent dual-energy X-ray absorptiometry (DEXA) between January 2005 and December 2017. DEXA examination data were defined as the index date, and all laboratory values were measured within one month from the index date.

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Background: To investigate the diagnostic performance of the neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and monocyte-to-lymphocyte ratio (MLR) in the diagnosis of rheumatoid arthritis (RA) in subjects with undifferentiated inflammatory arthritis (UIA). Methods: This retrospective cohort study investigated 201 female patients with UIA (≥1 swollen joint) and 280 age-matched, healthy female controls. “Clinical RA” was defined based on the clinical judgment of a rheumatologist and “disease-modifying anti-rheumatic drugs (DMARDs) RA” was defined as a case of initiating DMARDs treatment within 6 months after the first visit.

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Dysregulation of cyclin-dependent kinases (CDKs) can promote unchecked cell proliferation and cancer progression. Although focal adhesion kinase (FAK) contributes to regulating cell cycle progression, the exact molecular mechanism remains unclear. Here, we found that FAK plays a key role in cell cycle progression potentially through regulation of CDK4/6 protein expression.

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In the present report, green synthesis of titanium dioxide nanoparticles (TiO NPs) was performed by upcycling mangosteen (Garcinia mangostana) pericarp extract (methanol and ethyl acetate extracts). Field emission scanning electron microscopy images revealed an aggregated structure with a highly porous network of TiO NPs. TiO NPs synthesized with ethyl acetate extract (EtOAc-TiO NPs) exhibited more monodispersity and possessed smoother surfaces than the control TiO NPs (Con-TiO NPs) and TiO NPs synthesized with methanol extract (MeOH-TiO NPs).

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Rationale: Vascular smooth muscle cells (SMCs) exhibit remarkable plasticity and can undergo dedifferentiation upon pathological stimuli associated with disease and interventions.

Objective: Although epigenetic changes are critical in SMC phenotype switching, a fundamental regulator that governs the epigenetic machineries regulating the fate of SMC phenotype has not been elucidated.

Methods And Results: Using SMCs, mouse models, and human atherosclerosis specimens, we found that FAK (focal adhesion kinase) activation elicits SMC dedifferentiation by stabilizing DNMT3A (DNA methyltransferase 3A).

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While dysregulation of RNA splicing has been recognized as an emerging target for cancer therapy, the functional significance of RNA splicing and individual splicing factors in brain tumors is poorly understood. Here, we identify SON as a master regulator that activates PTBP1-mediated oncogenic splicing while suppressing RBFOX2-mediated non-oncogenic neuronal splicing in glioblastoma multiforme (GBM). SON is overexpressed in GBM patients and SON knockdown causes failure in intron removal from the PTBP1 transcript, resulting in PTBP1 downregulation and inhibition of its downstream oncogenic splicing.

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Zhu-Tokita-Takenouchi-Kim (ZTTK) syndrome, an intellectual disability syndrome first described in 2016, is caused by heterozygous loss-of-function variants in SON. Its encoded protein promotes pre-mRNA splicing of many genes essential for development. Whereas individual phenotypic traits have previously been linked to erroneous splicing of SON target genes, the phenotypic spectrum and the pathogenicity of missense variants have not been further evaluated.

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Emerging evidence has shown that active enhancers are abundantly transcribed, generating long non-coding RNAs, called enhancer RNAs (eRNAs). While putative eRNAs are often observed from RNA sequencing, the roles of most eRNAs remain largely unknown. Previously, we identified putative enhancer regions at the MALAT1 locus that form chromatin-chromatin interactions under hypoxia, and one of these enhancers is located about 30 kb downstream of the NEAT1 gene and -20 kb upstream of the MALAT1 gene (MALAT1-20 kb enhancer).

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Aims: Vascular smooth muscle cells (VSMCs) normally exhibit a very low proliferative rate. Vessel injury triggers VSMC proliferation, in part, through focal adhesion kinase (FAK) activation, which increases transcription of cyclin D1, a key activator for cell cycle-dependent kinases (CDKs). At the same time, we also observe that FAK regulates the expression of the CDK inhibitors (CDKIs) p27 and p21.

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The gene SON is on human chromosome 21 (21q22.11) and is thought to be associated with hematopoietic disorders that accompany Down syndrome. Additionally, SON is an RNA splicing factor that plays a role in the transcription of leukemia-associated genes.

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While sustained nuclear factor-κB (NF-κB) activation is critical for proinflammatory molecule expression, regulators of NF-κB activity during chronic inflammation are not known. We investigated the role of focal adhesion kinase (FAK) on sustained NF-κB activation in tumor necrosis factor-α (TNF-α)-stimulated endothelial cells (ECs) both in vitro and in vivo. We found that FAK inhibition abolished TNF-α-mediated sustained NF-κB activity in ECs by disrupting formation of TNF-α receptor complex-I (TNFRC-I).

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A high incidence of acute megakaryoblastic leukemia (AMKL) in Down syndrome patients implies that chromosome 21 genes have a pivotal role in AMKL development, but the functional contribution of individual genes remains elusive. Here, we report that SON, a chromosome 21-encoded DNA- and RNA-binding protein, inhibits megakaryocytic differentiation by suppressing RUNX1 and the megakaryocytic gene expression program. As megakaryocytic progenitors differentiate, SON expression is drastically reduced, with mature megakaryocytes having the lowest levels.

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Silver nanoparticles (AgNPs) were synthesized via a green strategy using fifty-eight plant extracts that originated from Vietnam and Indonesia. Among the fifty-eight AgNP samples, we selected six AgNP samples synthesized by the extracts of Areca catechu, Hypotrachyna laevigata, Ardisia incarnata, Maesa calophylla, Maesa laxiflora and Adinandra poilanei. Remarkably, these six extracts exhibited higher 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity and reducing power than the other extracts.

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Focal adhesion kinase (FAK) is an integrin-associated protein tyrosine kinase that is frequently overexpressed in advanced human cancers. Recent studies have demonstrated that aside from FAK's catalytic activity in cancer cells, its cellular localization is also critical for regulating the transcription of chemokines that promote a favorable tumor microenvironment (TME) by suppressing destructive host immunity. In addition to the protumor roles of FAK in cancer cells, FAK activity within cells of the TME may also support tumor growth and metastasis through various mechanisms, including increased angiogenesis and vascular permeability and effects related to fibrosis in the stroma.

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