https://scholar.dgist.ac.kr/handle/20.500.11750/11738 2026-04-24T17:07:50Z 2026-04-24T17:07:50Z Cho, Jung-Ah Jeon, Sang Seo Choi, Go Woon Lee, Chang-Hun Kim, Sung-Jae https://scholar.dgist.ac.kr/handle/20.500.11750/60228 2026-04-15T18:01:47Z 2025-12-31T15:00:00Z

Title: Investigation on physical and physiological properties of extracellular vesicles derived from Enterococcus faecalis Author(s): Cho, Jung-Ah; Jeon, Sang Seo; Choi, Go Woon; Lee, Chang-Hun; Kim, Sung-Jae Abstract: Extracellular membrane vesicles (EVs) are nanosized particles that contain various molecules originating from their parental cells and are produced by all three domains of life, including bacteria. Bacterial EVs are known to contribute to bacterial infections and immune responses in various human diseases. Enterococcus faecalis is an opportunistic pathogen. In this study, we examined the physical and physiological properties of EVs generated by E. faecalis, including particle size, protein composition, and cytokine-inducing profiles. To this end, we isolated EVs from bacteria under different preparation processes, and also a certain condition with the addition of EGCG. First, the bacterial culture supernatants were directly ultracentrifuged (named "Rough"), or filtered through 0.45- or 0.22 mu m pore-sized membrane filters (named as "0.45 mu m" or "0.22 mu m," respectively). EVs from EGCG-treated bacteria were prepared using a 0.45 mu m pore-sized membrane filter and named "EGCG + 0.45 mu m." Each EV sample was subjected to DLS, SDS-PAGE, and cytokine array analyses. DLS results showed that the differently prepared EVs had distinct size distributions depending on the filtration process. SDS-PAGE results revealed unique protein profiles that differentiated EVs under each condition. Treatment of macrophages with each EV sample markedly increased cell viability and size. The cytokine profiles produced by macrophages in response to each EV preparation revealed both common and distinguishable factors. This study has significance in revealing aspects of the biological characteristics of EVs produced by E. faecalis, which have previously been largely unknown.

2025-12-31T15:00:00Z Han, Min Ae Ashim, Janbolat Ji, Youngheum Kang, Eunho Jeong, Minchan Kim, Sung Jae Yu, Wookyung Kim, Jin Hae Moon, Cheil Lee, Chang-Hun https://scholar.dgist.ac.kr/handle/20.500.11750/59909 2026-02-05T13:40:11Z

Title: Erythropoietin-derived Non-erythropoietic Peptides Conferring Oxidative Stress Resistance to Keratinocytes and Fibroblasts Author(s): Han, Min Ae; Ashim, Janbolat; Ji, Youngheum; Kang, Eunho; Jeong, Minchan; Kim, Sung Jae; Yu, Wookyung; Kim, Jin Hae; Moon, Cheil; Lee, Chang-Hun Abstract: Erythropoietin (EPO) exerts tissue-protective effects; however, its erythropoietic activity limits broader use. Three EPO-derived peptides (ML1-C1/C2/C3) were designed from the C-helix of EPO to remove erythropoietic activity while retaining cell-protective activity. Circular dichroism and nuclear magnetic resonance spectroscopies were used to assess the solution structures of ML1-C1/C2/C3 peptides. The peptide activities for cytoprotection and growth support were assessed using skin-relevant cells, HaCaT cells and 3T3-L1 cells, which proposes an effect on skin epithelial keratinocytes and pre-adipocytic fibroblasts, respectively. Also, an erythroid-precursor cell line, TF-1, was used to evaluate the erythropoietic function of the three peptides. Spectroscopic analyses of ML1-C1/C2/C3 peptides revealed similar secondary structures and different flexibilities between the peptides. While ML1-C1 and ML1-C3 had highly flexible loop-like structures, ML1-C2 had less flexible loop-like structures. Also, their cellular effects vary in a cell type-dependent manner. The EPO-derived peptides can attenuate H2O2-induced loss of viability in HaCaT cells and 3T3-L1 cells. Under low-serum conditions, the three peptides promoted HaCaT proliferation, whereas only ML1-C1 improved 3T3-L1 proliferation. In TF-1 cells, none of the peptides increased cell viability or hemoglobin staining, whereas recombinant human EPO did, indicating the lack of erythropoietic activity of the peptides under experimental conditions. These findings support the potential of EPO-derived peptides as skin-protective agents and motivate future work for skin therapeutics or cosmetic purposes.

Yeom, Jiwoo Lee, Sanghoon Ko, Young Ho Hong, Eunmi Kim, Jin Hae Coulombe, Pierre A. Lee, Chang-Hun https://scholar.dgist.ac.kr/handle/20.500.11750/59293 2025-12-30T18:01:11Z 2025-11-30T15:00:00Z

Title: Structure and function of the keratin 17 tail domain associated with keratin intermediate filament organization Author(s): Yeom, Jiwoo; Lee, Sanghoon; Ko, Young Ho; Hong, Eunmi; Kim, Jin Hae; Coulombe, Pierre A.; Lee, Chang-Hun Abstract: Keratins are the largest subgroup of intermediate filament proteins, forming 10-nm filaments from type I/II heterodimers, and occur primarily in epithelial cells. Keratin 6 (K6; type II) and Keratin 17 (K17; type I) show a complex expression pattern that includes induction following stress and in several diseases, including carcinomas. K17 is being used as a biomarker for several types of cancer. K6 and K17 sequences are respectively highly homologous to K5 and K14, which are expressed in the progenitor compartment of epidermis and related epithelia. The mechanical support roles of the K6/K17 and K5/K14 pairing require 10 nm filament assembly and the subsequent lateral association of these filaments to form thicker bundles. Previous studies showed that the non-helical tail domain of K14 is dispensable for 10 nm filament assembly but essential to the bundling of K5/ K14 filaments. Whether the K6/K17 pairing undergoes bundling, and whether the tail domain of K17 plays a role, is unknown. Here, we use sedimentation assays and electron microscopy to show that, when paired with K6, tailless K17 forms filaments that do not readily bundle. Nuclear magnetic resonance analysis revealed that the isolated K17 tail domain is an intrinsically disordered region (IDR). Follow-up studies with mutant K17 tail constructs suggest that IDR-like tail domains of keratins can form a curved local structure required for bundling and interact dynamically with other regions of keratin filaments in a flexible and heterogeneous manner.

2025-11-30T15:00:00Z Tabassum, Sidra Hu, Heng Wu, Silin Huang, Shuning Yang, Bosco Seong Kyu Lee, Chang-Hun Gusdon, Aaron W. Ren, Xuefang S. https://scholar.dgist.ac.kr/handle/20.500.11750/59292 2025-12-30T09:10:11Z 2025-11-30T15:00:00Z

Title: Differential Effects of Murine Stroke Models on Dopaminergic Neurons, Glial Responses, and Neurobehavioral Outcomes Author(s): Tabassum, Sidra; Hu, Heng; Wu, Silin; Huang, Shuning; Yang, Bosco Seong Kyu; Lee, Chang-Hun; Gusdon, Aaron W.; Ren, Xuefang S. Abstract: Stroke is a leading cause of disability worldwide, often resulting in persistent motor, cognitive, and emotional impairments. While the hippocampus and amygdala play critical roles in post-stroke behavioral changes, specific neuronal alterations and prolonged glial responses within these regions across different stroke types remain unclear. This study investigates the behavioral, neuronal, and glial effects of subarachnoid hemorrhage (SAH), transient middle cerebral artery occlusion (tMCAO), and photothrombotic stimulation (PTS) in mice. SAH and tMCAO models exhibited significant motor deficits, spatial and recognition memory impairments, and increased anxiety- and depressive-like behaviors, whereas the PTS model showed similar motor and cognitive impairments but lacked affective (anxiety- and depressive-like) behavioral changes. Immunohistochemical analysis revealed increased overlap of tyrosine hydroxylase (TH, a dopaminergic marker) process with NeuN (a neuronal marker) in the dentate gyrus (DG) of SAH and tMCAO mice, highlighting region-specific vulnerability to ischemic damage in the hippocampus. In the amygdala, elevated overlap of TH+ process with NeuN in SAH and tMCAO mice suggests enhanced dopaminergic involvement in emotional dysregulation. In contrast, the PTS model did not exhibit any changes in overlap of TH+ process with NeuN in either the hippocampus or amygdala, consistent with the absence of affective behavioral deficits. Additionally, SAH and tMCAO models exhibited persistent astrocytic and microglial activation in the amygdala, characterized by increased intensity and density without significant morphological changes, indicative of a chronic inflammatory response. The PTS model also showed increased microglial intensity and density without overt morphological changes, suggesting a more moderate, possibly subclinical inflammatory response. These findings highlight the differential effects of stroke models on behavior, neuronal populations, and glial responses in limbic regions. The pronounced dopaminergic and glial alterations in SAH and tMCAO may underlie post-stroke emotional and cognitive disturbances.

2025-11-30T15:00:00Z