👤 Min-Hee Ryu

Signal peptides (SPs) are short N-terminal sequences that direct proteins to the endoplasmic reticulum (ER). After cleavage of the SP, these proteins are mostly trafficked to the Golgi apparatus for secretion. Lipocalin-2 (LCN2), a neurotoxic secretory protein, was recently identified as a target of autophagy. The presence of an SP is a prerequisite for secretion and autophagic degradation. Based on these observations, we investigated whether the SP of LCN2 is sufficient to enable proteins to be secreted or degraded via autophagy. We fused the SP of LCN2 to a non-secretory green fluorescent protein (GFP) and found that this ER-generated GFP was either secreted or degraded via autophagy. These results indicate that the LCN2-derived SP alone is sufficient to direct proteins to the ER and subsequent secretion or autophagic degradation. This dual regulation was abolished when the SP was deleted from LCN2. Notably, the effect was preserved even when the LCN2 SP was replaced with the SP from brain-derived neurotrophic factor, another secretory protein. These results suggest that SPs with different sequences can similarly direct proteins to the ER and subsequent secretion or autophagic degradation. Furthermore, we found that even when LCN2 reached the Golgi apparatus for secretion, it could also be degraded via autophagy. Thus, we propose that SP-directed and ER-generated secretory proteins can undergo autophagic degradation during ER-Golgi transport, including at the ER, the ER-Golgi intermediate compartment, or the Golgi apparatus. Taken together, degradation of secretory proteins via autophagy suggests implications for the potential control of secretory protein homeostasis. Show less

Brain-derived neurotrophic factor (BDNF) has been suggested to support dopaminergic neuron's endurance and dopamine release. Its Val66Met polymorphism might modify Parkinson's disease (PD) evolution, although evidence in Asian populations remains limited. This study aimed to explore how the BDNF rs6265 genotypes are associated with the clinical characteristics and longitudinal progression patterns of PD patients in a Korean population. A total of 247 patients were enrolled and followed for a mean duration of 50.9 ± 23.9 months. Baseline and/or periodic assessments captured motor severity, non-motor burden, cognition, orthostatic stress, cardiac denervation, and presynaptic dopamine transporter availability. The repeated measures were manipulated to infer any genotypic differences in the trajectories of each clinical domain. Genotype frequencies were 31.2% (77/247) for Val/Val and 68.8% (170/247) for Met-allele carriers. Baseline clinical characteristics and presynaptic dopamine transporter availability were comparable between genotypes; however, Val homozygotes showed more preserved myocardial innervation and poorer non-frontal cognitive performance. Longitudinal analyses demonstrated genotype-specific increases in motor and cognitive severity. Compared to Met-allele carriers, the homozygous Val group exhibited accelerated motor progression and more rapid decline in frontal domain after three years of follow-up. The differences in myocardial denervation at diagnosis, cognitive profiles, and motor progression might suggest a potential modulatory role of BDNF polymorphism in PD progression in the Korean population. Show less

Abnormal accumulation of amyloid β (Aβ), which may result from excessive production or impaired clearance, is one of the pathomechanisms of Alzheimer's disease (AD). Plasmin is one of the important proteases involved in the Aβ clearance system. In this study, we investigated whether swertisin can regulate plasmin activity and reduce Aβ pathology. First, we examined whether swertisin regulated plasmin activity, mature brain-derived neurotrophic factor (mBDNF) levels, and plasminogen activator inhibitor-1 (PAI-1) activity in vitro. Next, we assessed the effect of swertisin on memory impairments in an Aβ-injected AD-like mouse model and in 5XFAD mice. To evaluate the involvement of plasmin in the effect of swertisin in the Aβ-injected AD-like mouse model, we used 6-aminocaproic acid (6-AA), a plasmin inhibitor. Additionally, we measured plasmin activity and mBDNF levels in the hippocampus of Aβ-injected AD-like mice and 5XFAD mice. Swertisin increased plasmin activity and mBDNF levels in hippocampal slices from both normal and 5XFAD mice. Moreover, swertisin ameliorated Aβ-induced synaptic long-term potentiation (LTP) deficits in hippocampal slices. Swertisin also mitigated memory impairments induced by ventricular injection of Aβ, and this effect was blocked by 6-AA. Furthermore, swertisin improved learning and memory in 5XFAD mice while reducing Aβ deposition and neuroinflammation. This study demonstrates that swertisin ameliorates AD-like pathology by regulating plasmin activity. Plasmin activated by swertisin may cleave Aβ aggregates and increase mBDNF levels, thereby protecting the brain from Aβ toxicity. Swertisin may represent an effective therapeutic strategy for AD patients. Show less

The apolipoprotein E (APOE) gene ε4 allele leads to increased Alzheimer disease risk and neuroinflammation and is also believed to play a role in postoperative delirium. However, the safety and feasibility of modulating apoE protein signaling to reduce postoperative neuroinflammation and delirium in older adults are unclear. To assess the safety and feasibility of the apoE mimetic peptide CN-105 for reducing delirium incidence and severity and neuroinflammation after noncardiac or nonintracranial surgery in older adults. This triple-blind, escalating dose, phase 2 randomized clinical trial enrolled patients from April 17, 2019, to December 28, 2022, at a tertiary academic medical center. Included patients were 60 years or older and scheduled for a noncardiac or nonintracranial surgery. Exclusion criteria were incarceration, planned chemotherapy within 6 weeks after surgery, or inability to undergo lumbar punctures. Data analyses were based on a modified intention-to-treat approach and were performed from August 14, 2023, to August 22, 2025. Patients were randomly assigned 3:1 to the CN-105 group or placebo group. The CN-105 group received intravenous CN-105 doses of 0.1, 0.5, or 1 mg/kg starting within 1 hour before surgery and administered every 6 hours afterward until hospital discharge or 13 doses were received. Patients in the placebo group followed the same administration schedule. The primary outcome was safety-the incidence and number of postoperative adverse events (AEs). Secondary outcomes included feasibility (rate of drug doses administered within 90 minutes of schedule), postoperative delirium incidence and severity, and postoperative changes in cerebrospinal fluid (CSF) cytokine levels (interleukin [IL] 6, granulocyte-colony stimulating factor [G-CSF], monocyte chemoattractant protein-1 [MCP-1], and IL-8). Among 203 enrolled patients, 186 (mean [SD] age, 68.7 [5.2] years; 119 males [64.0%]) were randomized (137 to the CN-105 group, 49 to the placebo group) and underwent surgery. The rates of grade 2 or higher AEs among patients in the CN-105 and placebo groups were 76.6% and 87.8% (relative risk [RR], 0.87; 95% CI, 0.76-1.00; P = .10). The CN-105 vs placebo group had fewer grade 2 or higher AEs per patient (median [IQR], 1 [1-3] vs 2 [1-5]; P = .03). The percentage of CN-105 doses administered within the time window was 94.6% (860 of 909; 95% CI, 92.9%-96.0%) in the CN-105 group and 93.8% (346 of 369; 95% CI, 90.8%-96.0%) in the placebo group. Among patients in the CN-105 vs placebo group, the postoperative delirium incidence was 19.3% vs 26.5% (odds ratio [OR], 0.66; 95% CI, 0.31-1.42; P = .29); the median (IQR) postoperative delirium severity scores were 1 (1-2) vs 2 (1-2) (P = .19); and the median difference in preoperative to 24-hour postoperative CSF cytokine-level changes were as follows: -0.39 pg/mL (95% CI, -0.93 to 0.14 pg/mL, P = .12) for IL-6, -0.84 pg/mL (95% CI, -3.06 to 1.40 pg/mL; P = .18) for G-CSF,-23.32 pg/mL (95% CI, -94.36 to 44.93 pg/mL; P = .57) for IL-8, and -2.36 pg/mL (95% CI, -58.57 to 58.62 pg/mL; P = .50) for MCP-1. In this phase 2 randomized clinical trial of older surgical patients, CN-105 (vs placebo) administration was feasible and did not increase AEs. A phase 3 trial is warranted to further evaluate the efficacy of CN-105 for reducing postoperative AEs and to more precisely determine its effects on postoperative delirium incidence and severity. ClinicalTrials.gov Identifier: NCT03802396. Show less

This review overviewed the recent paradigm shifts in the diagnosis and management of Alzheimer's disease (AD), emphasizing the 2024 Alzheimer's Association (AA) revised criteria, advances in cerebrospinal fluid (CSF) and blood-based biomarkers (BBMs), and practical considerations for anti-amyloid monoclonal antibody therapy. We conducted a narrative appraisal of consensus frameworks (2018 National Institute on Aging-Alzheimer's Association [NIA-AA] amyloid, tau, and neurodegeneration [AT(N)] and the 2024 AA criteria), clinical practice guidance from AA released in 2025, regulatory status of CSF and BBMs. Intended-use settings (triage vs. confirmatory) of BBMs and implementation of anti-amyloid anti-body treatments (lecanemab or donanemab) in real-world practice in Korea were also reviewed. The 2024 AA criteria define AD biologically and designate A and T as core biomarkers; Core 1 biomarkers can establish AD irrespective of symptoms, whereas Core 2 biomarkers refine staging. A two-cutoff BBM strategy (positive/intermediate/negative) reduces misclassification and guides confirmatory CSF/positron emission tomography (PET) or retesting. BBMs now approach CSF/PET accuracy for amyloid detection, enable triage and, in selected settings, confirmation, and show utility for monitoring treatment response. Integration of clinical stages (1-6) with biological stages (A-D) clarifies syndrome-pathology discordance. Special scenarios-maintenance after induction, APOE ε4 homozygotes, Down syndrome, and serious mental illness-require individualized risk-benefit assessment. In South Korea, constrained access to tau PET and some BBMs necessitates Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision-anchored evaluation with selective biomarker testing. Biomarker-oriented diagnosis and anti-amyloid therapies are reshaping AD care. Priorities include rigorous validation of BBMs across populations, equitable access to core biomarkers, safety strategies, and real-world evidence to implement maintenance and special-population care pathways. Show less

Osteomas are benign, slow-growing bony tumors that commonly develop in the craniofacial region; however, standardized diagnostic and treatment protocols remain limited. This study aimed to establish a systematic approach for the diagnosis, genetic evaluation, and surgical management of craniofacial osteomas, with emphasis on lesion distribution and gender prevalence. A retrospective review was conducted on 141 patients with craniofacial osteomas at Kyungpook National University Hospital between October 2011 and September 2025. All patients underwent clinical examinations and 3-dimensional computed tomography for diagnostic confirmation. Surgical excision was performed using direct, endoscopic, or bicoronal approaches based on lesion characteristics. Whole exome sequencing was performed in patients with multiple large osteomas to evaluate mutations in EXT1, EXT2, APC, MSH2, and MLH1 genes associated with Gardner syndrome. A total of 148 osteomas were identified. The frontal bone was the most common site (60.1%), followed by the parietal, mandibular, and occipital bones. Females accounted for 79.1% of cases. Genetic testing revealed no pathogenic variants related to Gardner syndrome, and no recurrences were observed during 6 months of follow-up. Craniofacial osteomas are benign, slow-growing lesions most frequently found in the frontal bone and are more prevalent among females. The integration of imaging-based diagnosis, tailored surgical techniques, and selective genetic testing allows for accurate evaluation, effective treatment, and favorable postoperative outcomes. Show less

Snail (SNAI1), a central transcription factor driving epithelial-mesenchymal transition (EMT), is pivotal in cancer metastasis and tissue remodeling. Owing to its labile nature, Snail activity is tightly controlled by post-translational modifications that dictate its stability. Here this review summarizes how the ubiquitin-proteasome system orchestrates Snail degradation through coordinated phosphorylation and ubiquitination, mediated by diverse E3 ligases and regulated by kinases, acetyltransferases and deubiquitinases. These mechanisms dynamically adjust Snail levels in both the cytoplasm and nucleus, thereby modulating EMT outcomes. In parallel, emerging studies reveal that chaperone-mediated autophagy (CMA) provides an additional layer of regulation. Through recognition of KFERQ-like motifs, CMA selectively directs cytoplasmic Snail to lysosomes for LAMP2A-dependent degradation, functioning as a quality control system. Impairment of CMA leads to nuclear accumulation of Snail, enhancing its EMT-inducing and prometastatic potential. Together, the ubiquitin-proteasome system and CMA represent complementary, context-dependent axes that maintain Snail homeostasis. Their disruption facilitates EMT activation and metastatic progression. By integrating recent findings, this review highlights the dual degradative control of Snail and its implications for cancer biology, providing a conceptual framework for therapeutic approaches aimed at restoring degradative balance and limiting metastasis. Show less

Type 2 diabetes mellitus (T2DM) is known to adversely impact brain health, leading to cognitive decline and brain tissue volume reduction. This study aimed to assess the damage to gray-white matter junction tissue volume (gwJTV) in T2DM patients with and without carotid artery plaques, and its association with various metabolic parameters. We conducted a cross-sectional study involving 69 T2DM patients, employing three-dimensional T1-weighted MRI scans to measure brain tissue volumes, particularly gwJTV, and analyzing blood samples for metabolic parameters. Voxel-based (VBA) and region-of-interest (ROI) analyses of gwJTV were performed to evaluate the group difference with and without carotid artery plaques and to determine correlations to metabolic biomarkers. Voxel-based and region-of-interest analyses revealed that participants with carotid plaques had lower gwJTV than those without at the specific brain area. ROI results study further demonstrated positive associations between gwJTV and metabolic parameters such as AST, ApoB, and LDL, and negative associations with C-peptide, creatinine, and hsCRP. Our findings suggest that gwJTV could be a valuable imaging biomarker for monitoring brain and vascular health in T2DM patients, particularly those affected by carotid atherosclerosis. Show less

Most cancer cells adopt a less efficient metabolic process of aerobic glycolysis with high level of glucose uptake followed by lactic acid production, known as the Warburg effect. This phenotypic transition enables cancer cells to achieve increased cellular survival and proliferation in a harsh low-oxygen tumor microenvironment. Also, the resulting acidic microenvironment causes inactivation of the immune system such as T-cell impairment that favors escape by immune surveillance. While lots of studies have revealed that tumor-derived EVs can deliver parental materials to adjacent cells and contribute to oncogenic reprogramming, their functionality in energy metabolism is not well addressed. In this study, we established prostate cancer cells PC-3AcT resistant to cellular death in an acidic culture medium driven by lactic acid. Quantitative proteomics between EVs derived from PC-3 and PC-3AcT cells identified 935 confident EV proteins. According to cellular adaptation to lactic acidosis, we revealed 159 regulated EV proteins related to energy metabolism, cellular shape, and extracellular matrix. These EVs contained a high abundance of glycolytic enzymes. In particular, PC-3AcT EVs were enriched with apolipoproteins including apolipoprotein B-100 (APOB). APOB on PC-3AcT EVs could facilitate their endocytic uptake depending on low density lipoprotein receptor of recipient PC-3 cells, encouraging increases of cellular proliferation and survival in acidic culture media via increased activity and expression of hexokinases and phosphofructokinase. The activation of recipient PC-3 cells can increase glucose consumption and ATP generation, representing an acquired metabolic reprogramming into the Warburg phenotype. Our study first revealed that EVs derived from prostate cancer cells could contribute to energy metabolic reprogramming and that the acquired metabolic phenotypic transition of recipient cells could favor cellular survival in tumor microenvironment. Show less

Aberrant fibroblast growth factor receptor (FGFR)-driven signaling, predominantly arising from FGFR2 amplification, plays a key role in gastric cancer pathogenesis. This open-label, phase 2 study evaluated the efficacy and safety of futibatinib, an irreversible FGFR1-4 inhibitor, in patients with gastric or gastroesophageal junction (GEJ) cancer harboring FGFR2 amplifications. Patients were treated with futibatinib 20 mg orally once daily in a 28-day cycle. The primary endpoint was objective response rate (ORR) per independent central review. Secondary endpoints included progression-free survival (PFS), overall survival (OS), and safety. Among 28 treated patients, the ORR per independent central review was 17.9 %, comprising five patients with a partial response (median duration of response, 3.9 months), and an additional nine patients with stable disease for a disease control rate of 50.0 %. Median PFS per independent central review and median OS were 2.9 and 5.9 months, respectively. The most common treatment-related adverse events (any grade) were hyperphosphatemia (89.3 %), decreased appetite (32.1 %), and increased aspartate aminotransferase (21.4 %). Only one (3.6 %) patient discontinued study treatment due to an adverse event. Futibatinib demonstrated modest antitumor activity with a safety profile consistent with previous reports in patients with gastric or GEJ cancer harboring FGFR2 amplifications, potentially warranting further investigation. Show less

Mitogen- and stress-activated protein kinase 1 (MSK1), a Ser/Thr kinase, phosphorylates nuclear proteins to increase their stability and DNA-binding affinity. Despite the role of MSK1 in promoting cancer progression in colorectal cancer (CRC), the precise molecular mechanisms remain unelucidated. Here we show that MSK1 expression induces the epithelial-mesenchymal transition (EMT) process and increases CRC cell metastasis. Furthermore, we discovered that MSK1 interacts with Snail, a key EMT regulator, and increases its stability by inhibiting ubiquitin-mediated proteasomal degradation. Importantly, MSK1 increased Snail protein stability by promoting deubiquitination rather than inhibiting its ubiquitination. Finally, we identified USP5 as an essential deubiquitinase that binds to Snail protein phosphorylated by MSK1. Based on the experimental data, in CRC, MSK1-Snail-USP5 axis can promote EMT and metastasis of CRC. Together, our findings provide potential biomarkers and novel therapeutic targets for further research in CRC. Show less

Breast cancer remains a significant health concern, with triple-negative breast cancer (TNBC) being an aggressive subtype with poor prognosis. Epithelial-mesenchymal transition (EMT) is important in early-stage tumor to invasive malignancy progression. Snail, a central EMT component, is tightly regulated and may be subjected to proteasomal degradation. We report a novel proteasomal independent pathway involving chaperone-mediated autophagy (CMA) in Snail degradation, mediated via its cytosolic interaction with HSC70 and lysosomal targeting, which prevented its accumulation in luminal-type breast cancer cells. Conversely, Snail predominantly localized to the nucleus, thus evading CMA-mediated degradation in TNBC cells. Starvation-induced CMA activation downregulated Snail in TNBC cells by promoting cytoplasmic translocation. Evasion of CMA-mediated Snail degradation induced EMT, and enhanced metastatic potential of luminal-type breast cancer cells. Our findings elucidate a previously unrecognized role of CMA in Snail regulation, highlight its significance in breast cancer, and provide a potential therapeutic target for clinical interventions. Show less

Mitochondrial dysfunction is a well-known contributor to aging and age-related diseases. The precise mechanisms through which mitochondria impact human lifespan, however, remain unclear. We hypothesize that humans with exceptional longevity harbor rare variants in nuclear-encoded mitochondrial genes (mitonuclear genes) that confer resistance against age-related mitochondrial dysfunction. Here we report an integrated functional genomics study to identify rare functional variants in ~ 660 mitonuclear candidate genes discovered by target capture sequencing analysis of 496 centenarians and 572 controls of Ashkenazi Jewish descent. We identify and prioritize longevity-associated variants, genes, and mitochondrial pathways that are enriched with rare variants. We provide functional gene variants such as those in MTOR (Y2396Lfs*29), CPS1 (T1406N), and MFN2 (G548*) as well as LRPPRC (S1378G) that is predicted to affect mitochondrial translation. Taken together, our results suggest a functional role for specific mitonuclear genes and pathways in human longevity. Show less

To investigate potential target genes associated with the diabetic condition in mouse cavernous endothelial cells (MCECs) for the treatment of diabetes-induced erectile dysfunction (ED). Mouse cavernous tissue was embedded into Matrigel, and sprouted cells were subcultivated for other studies. To mimic diabetic conditions, MCECs were exposed to normal-glucose (NG, 5 mmoL) or high-glucose (HG, 30 mmoL) conditions for 72 hours. An RNA-sequencing assay was performed to evaluate gene expression profiling, and RT-PCR was used to validate the sequencing data. We isolated MCECs exposed to the two glucose conditions. MCECs showed well-organized tubes and dynamic migration in the NG condition, whereas tube formation and migration were significantly decreased in the HG condition. RNA-sequencing analysis showed that MCECs had different gene profiles in the NG and HG conditions. Among the significantly changed genes, which we classified into 14 major gene categories, we identified that aging-related (9.22%) and angiogenesis-related (9.06%) genes were changed the most. Thirteen genes from the two gene categories showed consistent changes on the RNA-sequencing assay, and these findings were validated by RT-PCR. Our gene expression profiling studies showed that Show less

Immunohistochemical (IHC) assays for programmed death ligand 1 (PD-L1) expression are crucial for guiding immune checkpoint inhibitor therapies in advanced gastric adenocarcinoma (AGC). The results from clinical trials of various PD-L1 antibody clones are variable and the exchangeability of these assays is a highly sought goal. The aim of this study was to determine whether three different PD-L1 assays (SP263 and 22C3 on the Dako and Ventana platforms) are interchangeable through analysis of their concordance rate within samples between biopsy and paired resected specimens. One hundred pairs of biopsied and resected AGC specimens were collected and stained for PD-L1. The combined positive score (CPS) was used for the IHC analysis and a four tiered system was applied, i.e., <1, 1 to < 5, 5 to 50, and >50. The agreement for the different IHC assays was low across all cut-offs with the biopsied or resected specimens (biopsy, κ=0.17-0.453; resection, κ=0.02-0.311). The overall positive agreement (OPA) for the PD-L1 results from the biopsy and resection tissues was 100% (SP263, κ=1), 86% (22C3 on the Dako platform, κ=0.693) and 93% (22C3 on the Ventana platform, κ=0.82) at the CPS1 cut-off. The low concordances among the three PD-L1 IHC assays indicated that they cannot be used interchangeably in clinical practice. The results of the SP263 assay using CPS1 showed the highest agreement between the biopsy and resection specimens, suggesting SP263 may provide the most representative approach for the evaluation of PD-L1 status in gastric cancer. Show less

n-3 polyunsaturated fatty acids (PUFAs) and n-6 PUFAs are reported to have immunomodulatory effects, but few studies have examined these functions. Thus, we examined whether dietary n-3 and n-6 PUFAs are associated with the risk of gastric cancer and further investigated whether fatty acid desaturases 1 and 2 (FADS1 and FADS2) modify this association. In a case-control study, 1,464 participants (402 cases and 1,062 controls) were enrolled. A semi-quantitative food frequency questionnaire was utilized to measure dietary PUFA intake. Genotyping was performed using the Axiom® Exome 319 Array. Multivariable logistic models were established after adjusting for confounding variables. The risk of gastric cancer was significantly decreased among participants who had the highest tertile intake of docosahexaenoic acid (DHA), an n-3 PUFA, even after adjusting for covariates [odds ratios (OR) = 0.72, 95% confidence intervals (95% CIs) = 0.53-0.99]. However, no significant interaction according to FADS1 rs174546 or FADS2 rs174583 was observed. In conclusion, we observed a significant inverse association between dietary DHA and the risk of gastric cancer but found that FADS1 rs174546 and FADS2 rs174583 did not modify the association between dietary n-3 or n-6 PUFAs and gastric cancer risk. Show less

Post-translational protein modification by the small ubiquitin-related modifier (SUMO) regulates numerous cellular pathways, including transcription, cell division, and genome maintenance. The SUMO protease Ulp2 modulates many of these SUMO-dependent processes in budding yeast. From whole-genome RNA sequencing (RNA-seq), we unexpectedly discovered that cells lacking Ulp2 display a twofold increase in transcript levels across two particular chromosomes: chromosome I (ChrI) and ChrXII. This is due to the two chromosomes being present at twice their normal copy number. An abnormal number of chromosomes, termed aneuploidy, is usually deleterious. However, development of specific aneuploidies allows rapid adaptation to cellular stresses, and aneuploidy characterizes most human tumors. Extra copies of ChrI and ChrXII appear quickly following loss of active Ulp2 and can be eliminated following reintroduction of ULP2, suggesting that aneuploidy is a reversible adaptive mechanism to counteract loss of the SUMO protease. Importantly, increased dosage of two genes on ChrI-CLN3 and CCR4, encoding a G1-phase cyclin and a subunit of the Ccr4-Not deadenylase complex, respectively-suppresses ulp2Δ aneuploidy, suggesting that increased levels of these genes underlie the aneuploidy induced by Ulp2 loss. Our results reveal a complex aneuploidy mechanism that adapts cells to loss of the SUMO protease Ulp2. Show less

Heterochromatin protein 1 (HP1) is an epigenetic modifier of gene regulation and chromatin packing via binding to trimethylated histone H3 lysine 9 (H3K9). HP1 plays an important role in gene activation as well as gene repression in heterochromatin and euchromatin. However, the role of individual HP1 proteins in human diseases remains elusive. Here, we show that HP1β negatively regulates the expression and activation of matrix metallopeptidase (MMP)2, which mediates cancer metastasis by destructing type Ⅳ collagen. Reduced HP1β expression correlates with the increased level of pro- and active-MMP2 in colon cancer cells. Consistently, HP1β knockdown (KD) increased and HP1β overexpression decreased the mRNA level of MMP2 and membrane type 1 metallopeptidase (MT1-MMP). Furthermore, cancer cells overexpressing HP1β showed impaired migratory ability, whereas HP1β‑deleted cancer cells had increased migration. HP1β negatively regulates MMP2 expression in a transcriptional level and prevents MMP2 activation through reducing the expression of MT1‑MMP. These findings shed new light on HP1β as a molecular regulator and an efficient therapeutic target of metastatic cancer. Show less

The individuals carrying melanocortin-1 receptor (MC1R) variants, especially those associated with red hair color, fair skin, and poor tanning ability (RHC trait), are more prone to melanoma; however, the underlying mechanism is poorly defined. Here, we report that UVB exposure triggers phosphatase and tensin homolog (PTEN) interaction with wild-type (WT), but not RHC-associated MC1R variants, which protects PTEN from WWP2-mediated degradation, leading to AKT inactivation. Strikingly, the biological consequences of the failure of MC1R variants to suppress PI3K/AKT signaling are highly context dependent. In primary melanocytes, hyperactivation of PI3K/AKT signaling leads to premature senescence; in the presence of BRAF(V600E), MC1R deficiency-induced elevated PI3K/AKT signaling drives oncogenic transformation. These studies establish the MC1R-PTEN axis as a central regulator for melanocytes' response to UVB exposure and reveal the molecular basis underlying the association between MC1R variants and melanomagenesis. Show less

The genetic mutations causing the constitutive activation of MEK/ERK have been regarded as an initiating factor in papillary thyroid carcinoma (PTC). The ERK-specific dual specificity phosphatase 6 (DUSP6) is part of the ERK-dependent transcriptional output. Therefore, the coordinated regulation of the activities of ERK kinases and DUSP6 may need to be reestablished to make new balances in PTC. To investigate the role of DUSP6 in the regulation of ERK1/2 (MAPK3/1)-dependent transcription, 42 benign neoplasms and 167 PTCs were retrospectively analyzed by immunohistochemistry with dideoxy sequencing to detect BRAF(V600E) mutation. The expressions of total ERK1/2, DUSP6, c-Fos (FOS), c-Myc (MYC), cyclin D1, and PCNA were markedly increased in PTC compared with those in benign neoplasms. However, phospho-ERK1/2 was detected in only eight (4.8%) cases out of 167 PTC samples. Unexpectedly, the staining intensity and nuclear localization of ERK1/2 were not affected by the presence or absence of the BRAF(V600E) mutation. However, the expressions of c-Fos and PCNA were elevated in BRAF(V600E)-positive PTC compared with those in BRAF(V600E)-negative PTC. Interestingly, the higher staining intensities of DUSP6 were associated with the level of total ERK1/2 expression (P=0.04) and with high-risk biological features such as age (P=0.05), tumor size (P=0.01), and extrathyroidal extension (linear by linear association, P=0.02). In addition, DUSP6 silencing significantly decreased the cell viability and migration rate of FRO cells. The coordinated upregulation of total ERK1/2 and its phosphatase, DUSP6, is related to bare detection of phospho-ERK1/2 in PTC regardless of BRAF(V)(600E) mutation status. A link between DUSP6 expression and high-risk features of PTC suggested that DUSP6 is an important independent factor affecting the signaling pathways in established PTC. Show less

Niemann Pick disease type C1 (NPC) is an autosomal recessive disease characterized by progressive neurological deterioration leading to premature death. In this study, we hypothesized that human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs) have the multifunctional abilities to ameliorate NPC symptoms in the brain. To test this hypothesis, hUCB-MSCs were transplanted into the hippocampus of NPC mice in the early asymptomatic stage. This transplantation resulted in the recovery of motor function in the Rota Rod test and impaired cholesterol homeostasis leading to increased levels of cholesterol efflux-related genes such as LXRα, ABCA1, and ABCG5 while decreased levels of 3-hydroxy-3-methylglutaryl coenzyme A reductase were observed in NPC mice. In the cerebrum, hUCB-MSCs enhanced neuronal cell survival and proliferation, where they directly differentiated into electrically active MAP2-positive neurons as demonstrated by whole-cell patch clamping. In addition, we observed that hUCB-MSCs reduced Purkinje neuronal loss by suppression of inflammatory and apoptotic signaling in the cerebellum as shown by immunohistochemistry. We further investigated how hUCB-MSCs enhance cellular survival and inhibit apoptosis in NPC mice. Neuronal cell survival was associated with increased PI3K/AKT and JAK2/STAT3 signaling; moreover, hUCB-MSCs modulated the levels of GABA/glutamate transporters such as GAT1, EAAT2, EAAT3, and GAD6 in NPC mice as assessed by Western blot analysis. Taken together, our findings suggest that hUCB-MSCs might play multifunctional roles in neuronal cell survival and ameliorating motor deficits of NPC mice. Show less

Isoliquiritigenin (ILQ), a flavonoid obtained from Glycyrrhizae species, has an antioxidant effect. This study investigated the potential of ILQ for inhibiting liver X receptor-α (LXRα)-mediated lipogenesis and steatosis in hepatocytes and its underlying molecular basis. Treatment with ILQ antagonized the ability of an LXRα agonist (T0901317) to activate sterol regulatory element binding protein-1c (SREBP-1c), thereby repressing transcription of fatty acid synthase, acetyl-CoA carboxylase, ATP-binding cassette transporter-A1, and stearoyl-CoA desaturase-1. ILQ treatment inhibited activating phosphorylation of JNK1 elicited by palmitate or TNFα. JNK1, but not JNK2, increased LXRα phosphorylation at serine residues, promoting LXRα activation. The ability of ILQ to inhibit JNK1 downstream of ASK1-MKK7 led to the repression of T0901317-inducible LXRα and SREBP-1c activation. In mice fed a high-fat diet, ILQ treatment inhibited hepatic steatosis, as shown by a decrease in fat accumulation and repression of lipogenic genes. The results of blood biochemistry and histopathology confirmed attenuation of high-fat diet-induced liver injury by ILQ. Moreover, ILQ inhibited oxidative stress, as indicated by decreases in thiobarbituric acid-reactive substance formation, iNOS and COX2 induction, and nitrotyrosinylation. Our results demonstrate that ILQ has the ability to repress LXRα-dependent hepatic steatosis through JNK1 inhibition and protect hepatocytes from oxidative injury inflicted by fat accumulation. Show less

Human infection by Campylobacter jejuni is mainly through the consumption of contaminated poultry products, which results in gastroenteritis and, rarely, bacteremia and polyneuropathies. In this study, six C. jejuni-specific bacteriophages (CPS1-6) were isolated by the spot-on-the-lawn technique from chicken samples in Korea and characterized for potential use as biocontrol agents. All isolated bacteriophages exhibited a high specificity, being able to lyse only C. jejuni, but not other Gram-negative bacteria, including C. coli, Escherichia coli, Salmonella spp., and Gram-positive bacteria. Bacteriophages contain an icosahedral head and a contractile tail sheath in transmission electron microscopy, and possess ds-DNA with an average genome size of approximately 145 kb; therefore, all bacteriophages are categorized into the Myoviridae family. Bacterial lysis studies in liquid media revealed that CPS2 could be used to control the growth of C. jejuni. Show less

The pathology of diabetic retinopathy includes dilatation and beading of retinal vessels, and vascular sheathing. To gain a better understanding of the molecular events leading to diabetic retinopathy, we investigated disease-specific gene responses by screening differential expression using cDNA microarray. Male Sprague-Dawley rats were intraperitoneally injected with streptozotocin (STZ, 50 mg/kg) or the control buffer and were maintained for 6 weeks. Total RNA extracted from the retinas of both groups was used for cDNA microarray analysis. Signals from all the spots representing hybridized DNA were quantified and compared between the normal and diabetic rat retinas. Among 1176 genes analyzed, the retinal expression of glucose-dependent insulinotropic polypeptide (GIP) was found to increase in STZ-induced diabetic rats compared to controls. GIP is a secreted protein, known to be released from the small intestine, which potentiates glucose-induced insulin secretion from the pancreas. However, the expression of GIP and its receptor (GIPR) has not been previously noted in the rat retina. To further validate the expression of GIP in the rat retina and to determine its possible role in the development of early diabetic retinopathy, we investigated its expression by RT-PCR, Northern blotting, and immunohistochemistry in normal and diabetic rat retinas. GIP mRNA and protein are not only expressed in the rat retina, but their levels are greater in the diabetic rat as compared to controls. And GIPR expression was also upregulated in the retinas of STZ-induced diabetic rats. We here demonstrate for the first time the expression of GIP and GIPR in the rat retina. And we also revealed some genetic events in the early stage of diabetic retinopathy including the de novo increment of GIP and GIPR expression in the retina. Show less

A partial C-terminal cDNA sequence of a novel Drosophila mitogen-activated protein kinase phosphatase (MKP), designated DMKP-3, was identified from an epitope expressed sequence tag database, and the missing N-terminal cDNA fragment was cloned from a Drosophila cDNA library. DMKP-3 is a protein of 411 amino acids, with a calculated molecular mass of 45.8 kDa; the deduced amino acid sequence is most similar to that of mammalian MKP-3. Recombinant DMKP-3 produced in Escherichia coli retained intrinsic tyrosine phosphatase activity. In addition, DMKP-3 specifically inhibited extracellular-signal-regulated kinase (ERK) activity, but was without a significant affect on c-Jun N-terminal kinase (JNK) and p38 activities, when it was overexpressed in Schneider cells. DMKP-3 interacted specifically with Drosophila ERK (DERK) via its N-terminal domain. In addition, DMKP-3 specifically inhibited Elk-1-dependent trans-reporter gene expression in mammalian CV1 cells, and dephosphorylated activated mammalian ERK in vitro. DMKP-3 is uniquely localized in the cytoplasm within Schneider cells, and gene expression is tightly regulated during development. Thus DMKP-3 is a Drosophila homologue of mammalian MKP-3, and may play important roles in the regulation of various developmental processes. Show less