Joon Hyung Sohn

Adipose tissue-derived mesenchymal stem cells cultured at high density express IFN-β and suppress the growth of MCF-7 human breast cancer cells.

Although it has been reported that mesenchymal stem cells (MSCs) suppress tumor growth in vitro and in vivo, little is known about the underlying molecular mechanisms. We found that type I interferon is expressed in adipose tissue-derived stem cells (ASCs) cultured at high density, and ASCs and their conditioned medium (ASC-CM) suppress the growth of MCF-7 cells in vitro. Growth inhibition was amplified by glucose deprivation that resulted from high density culture of ASCs after 3days. The cytotoxic effect of the ASC-CM obtained from high density culture of ASCs was neutralized by anti-IFN-β antibody. STAT1 was phosphorylated in MCF-7 cells treated with ASC-CM, and JAK1/JAK2 inhibitor treatment decreased STAT1 phosphorylation. The cytotoxic effect of ASC-CM was reduced especially by JAK1 inhibitors in MCF-7 cells. Our findings suggest that ASCs cultured at high density express type I interferons, which suppresses tumor growth via STAT1 activation resulting from IFN-β secretion in MCF-7 breast cancer cells.

Repression of human telomerase reverse transcriptase using artificial zinc finger transcription factors.

Telomerase activation is a key step in the development of human cancers. Expression of the catalytic subunit, human telomerase reverse transcriptase (hTERT), represents the limiting factor for telomerase activity. In this study, we have used artificial zinc finger protein (ZFP) transcription factors (TF) to repress the expression of hTERT in human cancer cell lines at the transcriptional level. We have constructed four-fingered ZFPs derived from the human genome which binds 12-bp recognition sequences within the promoter of the hTERT gene and fused them with a KRAB repressor domain to create a potent transcriptional repressor. Luciferase activity was decreased by >80% in all of the transcriptional repressors with luciferase reporter assay. When they were transfected into the telomerase-positive HEK293 cell line, a decrease of mRNA level and telomerase activity together with shortening of telomere length was observed. Actual growth of HEK293 cells was also inhibited by transfection of artificial ZFP-TFs. The repression was maintained for 100 days of culture. The repression of telomerase expression by artificial ZFP-TFs targeting the promoter region of the hTERT presents a new promising strategy for inhibiting the growth of human cancer cells. Mol Cancer Res; 8(2); 246–53

Comparative Ultrastructures of the Fertilized Egg Envelopes in Nothobranchius guentheri and Nothobranchius patrizii, Nothobranchiidae, Teleostei

Fish eggs are surrounded by an acellular structure, egg envelope. It plays a role in diffusive exchanges of gases such as carbon dioxide and oxygen, selective transport of materials into the egg, protections for physical damage (Donovan & Hart, 1986) and from chemicals and pathogens, and polyspermy prevention (Harvey et al., 1983; Cameron & Hunter, 1984). In teleost, the fine structure of the fertilized egg envelope differ according to the physiochemical characteristics of the water environment (Lönning, 1972). These ultrastructures have related with environmental factors (Stehr & Hawkes, 1979), and type of spawning place (Ivankov & Kurdyayeva, 1973). Also, the structure of the egg envelope differ according to species as well as by family (Deung et al., 1999; Kim et al., 2002). Even eggs of the same species have been reported to have different shapes depending on their geographical distribution (Brummett & Dumont, 1981). The Guentheri killifish (Nothobranchius guentheri) belong to Nothobranchiidae also known as the redtail notho. These species live in water holes, streams, and marshes in Africa (Huber, 1996). The food are mosquito larvae and plankton. During the dry season when the temporary pools of water the fish inhabit dry up and the adult fish perish, specially adapted

Functional Expression of P2Y Receptors in WERI-Rb1 Retinoblastoma Cells

P2Y receptors are metabotropic G-protein-coupled receptors, which are involved in many important biologic functions in the central nervous system including retina. Subtypes of P2Y receptors in retinal tissue vary according to the species and the cell types. We examined the molecular and pharmacologic profiles of P2Y purinoceptors in retinoblastoma cell, which has not been identified yet. To achieve this goal, we used Ca(2+) imaging technique and western blot analysis in WERI-Rb-1 cell, a human retinoblastoma cell line. ATP (10 µM) elicited strong but transient [Ca(2+)](i) increase in a concentration-dependent manner from more than 80% of the WERI-Rb-1 cells (n=46). Orders of potency of P2Y agonists in evoking [Ca(2+)](i) transients were 2MeS-ATP>ATP>>UTP=αβ-MeATP, which was compatible with the subclass of P2Y(1) receptor. The [Ca(2+)](i) transients evoked by applications of 2MeS-ATP and/or ATP were also profoundly suppressed in the presence of P2Y(1) selective blocker (MRS 2179; 30 µM). P2Y(1) receptor expression in WERI-Rb-1 cells was also identified by using western blot. Taken together, P2Y(1) receptor is mainly expressed in a retinoblastoma cell, which elicits Ca(2+) release from internal Ca(2+) storage sites via the phospholipase C-mediated pathway. P2Y(1) receptor activation in retinoblastoma cell could be a useful model to investigate the role of purinergic [Ca(2+)](i) signaling in neural tissue as well as to find a novel therapeutic target to this lethal cancer.

Serum leptin level is associated with phase angle in CKD5 patients not undergoing dialysis

Objective Malnutrition is very complex in patients with end-stage renal disease (ESRD) and is associated with poor prognosis. This is because hemodynamic changes, hormonal changes, persistent inflammatory reactions, and fluid overloads are more complicated as uremia is worsening. Bio-impedance spectroscopy (BIS) is a useful method to estimate fluid balance (Overhydration/ extracellular water, OH/ECW) and nutritional status (Phase angle, PhA). We aimed to evaluate the volume and nutritional status by BIS and to investigate the relationship between the appetite regulating hormones and the parameters of BIS in patients with stage 5 chronic kidney disease not undergoing dialysis (CKD5-ND). Methods We enrolled a total of 91 CKD5-ND patients. We measured routine serum markers including albumin and NT-proBNP and the appetite regulating hormones, leptin and ghrelin. We defined poor nutritional status as a PhA < 4.5°, and proper nutritional status as a PhA ≥ 4.5°. We also evaluated each patient’s nutritional status by assessing their geriatric nutritional risk index (GNRI) and their volume status by measuring NT-proBNP. Results Forty-one patients (45%) had poor nutritional status. Patients with a poor nutritional status had significantly higher OH/ECW (29.6 ± 12.7% vs. 6.2 ± 10.3%, p<0.001) and lower levels of leptin (3.8 ± 3.1 vs. 7.0 ± 6.2 ng/mL, p = 0.004) than those with proper nutritional status. PhA was associated with GNRI (r = 0.597, P<0.001) and NT-proBNP was associated with OH/ECW (r = 0.384, P<0.001). Leptin was negatively correlated with OH/ECW (r = -0.288, p = 0.006). In contrast, leptin was positively correlated with PhA (r = 0.263, p = 0.012). In multivariate logistic regression, high level of leptin (OR 7.00, 95% CI 1.74–28.10) was associated with proper nutrition, while an increased OH/ECW (OR 0.65, 95% CI 0.51–0.84) was associated with poor nutrition. Conclusions Our study demonstrates that CKD5-ND patients with poor nutrition generally also suffer from excessive body fluid. Low leptin level suggests poor nutrition in CKD5-ND patients. PhA could be used as a nutritional index for ESRD patients.

A PPAR-Gamma Agonist Rosiglitazone Suppresses Fibrotic Response in Human Pterygium Fibroblasts by Modulating the p38 MAPK Pathway

Purpose Fibroblast activation may play an important role in pterygium progression. Synthetic peroxisome proliferator-activated receptor γ (PPAR-γ) ligands have been shown to be effective antifibrotic agents against transforming growth factor β1 (TGF-β1) induced fibrosis in several tissues. We aimed to investigate the antifibrotic effects of the PPAR-γ ligand rosiglitazone in pterygium fibroblasts and the underlying mechanisms. Methods Profibrotic activation was induced by TGF-β1 in primary cultured human pterygium fibroblasts and the effect of rosiglitazone treatment on α-smooth muscle actin (α-SMA), and extra cellular matrix proteins synthesis was detected by western blotting, real-time PCR, immunostaining, and flow cytometry. Pharmaceutical inhibition of PPAR-γ receptor was used to determine the dependency or otherwise of rosiglitazones action on PPAR-γ signaling. Major signaling pathways downstream of TGF-β1 were investigated by western blotting to assess their possible association with rosiglitazones effect. Cell viability and apoptosis were investigated to assess drug-induced cytotoxicity, and the effect of rosiglitazone treatment on cell migration was further determined. Results α-SMA and fibronectin synthesis induced by TGF-β1 were suppressed by rosiglitazone treatment in a dose-dependent manner. Rosiglitazone also inhibited intrinsic TGF-β1 expression. Smad2/3, ERK1/2, and P38 pathways were activated in response to TGF-β1. Rosiglitazone suppressed TGF-β1-induced P38 MAPK activation, while ERK1/2 and Smad2/3 signaling remained unaffected. The observed antifibrotic effect of rosiglitazone was not affected by the PPAR-γ antagonist GW9662, indicating it is not PPAR-γ dependent. Rosiglitazone also inhibited the proliferation and migration of pterygium fibroblasts. Conclusions Rosiglitazone suppresses TGF-β1-induced myofibroblast activation and extra cellular matrix synthesis in pterygium fibroblasts at least partly through the modulation of the p38 MAPK pathway.

Serum Fibroblast Growth Factor 21 and New-Onset Metabolic Syndrome: KoGES-ARIRANG Study

Purpose Fibroblast growth factor 21 (FGF21) is a crucial metabolic regulator, with multiple favorable effects on glucose homeostasis and lipid metabolism. Since serum FGF21 level has been implicated as a potential marker for the early identification of metabolic syndrome (MetS), we investigated the association between serum FGF21 level and the development of MetS in a population-based prospective study. Materials and Methods We conducted a prospective study of 221 randomly sampled adults without MetS from a general population-based cohort study who were examined from 2005–2008 (baseline) and from 2008–2011 (follow-up). Baseline serum FGF21 levels were analyzed using enzyme-linked immunosorbent assay. Results During the average 2.8-year follow-up period, 82 participants (36.6%) developed new-onset MetS. Serum FGF21 levels were significantly higher in patients with new-onset MetS than in those without MetS (209.56±226.80 vs. 110.09±81.10, p<0.01). In multivariate adjusted models, the odds for MetS development were greater in patients with serum FGF21 levels in the highest quartile, compared to those in the lowest quartile (3.84, 95% confidence interval: 1.59–9.28). Conclusion Serum FGF21 level was an independent predictor for new-onset MetS in a population-based prospective study.

Comparative ultrastructure of the fertilized egg envelope in Corydoras adolfoi and Corydoras sterbai, Callichthyidae, Teleostei

In teleost, the structural characteristics of fertilized egg and egg envelope are very important for classification of genus or species. The structures of fertilized egg and egg envelope from Corydoras adolfoi and Corydoras sterbai, Callichthyidae, Siluriformes in teleost were examined by scanning and transmission electron microscopes to confirm whether these morphological structures have specificities of species and family or not. The fertilized eggs of C. adolfoi and C. sterbai were non‐transparent, spherical, demersal, and strong adhesive. There were no structural differences between two species through the light microscope. The size of the fertilized eggs of C. adolfoi was 1.95 ± 0.03 mm (n = 20), and that of C. sterbai was 1.92 ± 0.03 mm (n = 20). The perivitelline space was almost not developed in both species. In both species, the adhesive protuberances structures were on the outer surface of egg envelope. And fibrous structures were specially located at attachment part of spawning bed. And the egg envelope consisted of two layers, an inner lamellae layer and an outer strong adhesive layer with high electron dense protuberances structures in cross section. Consequentially, the fertilized eggs, outer surface on the egg envelope and cross section of egg envelope have identical structure. So, these structural characteristics of fertilized eggs and egg envelope show genus Corydoras specificity.

Pancreatic radiation effect in apoptosis-related rectal radiation toxicity

Abstract Pancreatic radiation effect (PRE) can be a component of gastrointestinal tract (GIT) radiotoxicity. This inter-organ correlation between the GIT and the pancreas was assessed through a rat model. Separate local irradiation to the abdomen and the pelvis was applied concurrently for 8-week-old male Sprague Dawley rats. Abdominal irradiation was categorized into pancreatic shield (PS) and non-pancreatic shield (NPS) irradiation. After 5 Gy and 15 Gy irradiation, the rectal mucosa was analyzed at the first week (early phase, Ep) and the 14th week (late phase, Lp). A slow gain in body weight was observed initially, particularly in the NPS group receiving a 15 Gy dose (P < 0.001). The large number of apoptotic bodies after 15 Gy at Ep decreased at Lp. At Ep for the 5-Gy group, the NPS group revealed more fibrotic change than the PS group (P = 0.002). Cleaved caspase-3 (CCP3) expression was greater at Lp, and the Ep–Lp increase was prominent in the NPS-15-Gy group (P = 0.010). At Lp, for 15 Gy irradiation, CCP3 was expressed more in the NPS group than in the PS group (P = 0.032). Despite no direct toxicity difference between the PS and NPS groups, small changes in parameters such as fibrosis or CCP3 expression suggest that pancreatic shielding does have an effect on the radiation response in the rectal mucosa, which suggests a need for a multi-organ effect-based approach in GIT radiotoxicity assessment.

PS 11-45 A PROSPECTIVE STUDY OF LEUKOCYTE DNA COPY NUMBER AND NEW ONSET METABOLIC SYNDROME: THE ARIRANG STUDY

Objective: Metabolic syndrome (MetS) is characterized by a group of defects of metabolic origin which are possibly involved in mitochondrial DNA (mtDNA) alteration of mtDNA content, but there was no prospective study of the predictive value of leukocyte mtDNA copy number to identify individuals at high risk of new-onset metabolic syndrome. We investigated whether leukocyte mtDNA copy number predicts the metabolic syndrome in a population-based longitudinal study. Design and Method: A prospective cohort study was conducted of random sample 221 adults aged 40–70 years without metabolic syndrome examined in 2005–2008 (baseline) and 2008–2011 (follow-up). Baseline mtDNA copy number of leukocytes was measured using quantitative polymerase chain reaction. Results: During an average of 2.8 years of follow-up, 82 (36.6%) developed new onset metabolic syndrome. The mean mtDNA copy number in metabolic syndrome was significantly lower than that in non-metabolic syndrome (113.79 ± 51.31 vs. 132.79 ± 51.31/cell, p < 0.001) In multivariable-adjusted models, the odds ratio for new onset metabolic syndrome comparing the highest with the lowest quartiles of mtDNA copy number was 0.34 (95% CI 0.13–0.91). The corresponding odds ratios for high waist circumference, low HDL cholesterol, high triglycerides, high blood pressure, and high blood glucose were 0.33(0.10–1.06), 0.26 (0.10–0.68), 0.40 (0.17–0.94), 0.70 (0.31–1.57), and 0.70 (0.31–1.61), respectively. Conclusions: Increased leukocyte mtDNA copy number is an independent protective factor for new onset metabolic syndrome and its components. Leukocyte mtDNA copy number might be a novel biomarker involved in the bioenergetics change of mitochondria.