Hyunsu Choi

Association between interleukin-4R and TGF-β1 gene polymorphisms and the risk of colorectal cancer in a Korean population.

Aim  Colorectal cancer is associated with inflammatory bowel disease. The mechanisms of how different genetic make‐ups of cytokines might influence the individual susceptibility to develop particular types of tumours are still unknown. The authors analysed the association between genetic polymorphisms in cytokine/cytokine receptor genes and the risk of colorectal cancer in a Korean population.

Antiangiogenic Effects of Axitinib, an Inhibitor of Vascular Endothelial Growth Factor Receptor Tyrosine Kinase, on Laser-Induced Choroidal Neovascularization in Mice

Purpose: To investigate the effects of axitinib, an inhibitor of vascular endothelial growth factor receptors, on choroidal neovascularization (CNV) in an animal model of neovascular age-related macular degeneration (AMD). Methods: Experimental CNV lesions were induced in C57BL/6 mice by laser photocoagulation. Beginning 1 day after CNV induction, mice were treated with axitinib (5 mg/kg/day) or vehicle for 2 weeks. In other groups of mice, axitinib or vehicle treatment was started 7 days after the laser application to determine the effect of the drug on established CNV. Untreated mice were used as a baseline group. Two weeks after laser injury, the extent of CNV was assessed from choroidal flat mounts perfused with fluorescein-labeled dextran. Immunofluorescence staining with isolectin IB4 was also used to quantify the CNV lesions. Results: Orally administered axitinib inhibited CNV growth in the laser-induced CNV model. Axitinib caused a 70.1% inhibition of CNV lesions compared to vehicle-treatment (p < 0.001). Axitinib also caused a significant regression of established CNV, reducing the area by 71.1% compared to vehicle treatment (p < 0.001). Moreover, immunofluorescence staining showed that the area of isolectin IB4 labeled vessels was smaller in the axitinib-treated group compared to the vehicle-treated group (p < 0.001). Conclusions: Axitinib effectively inhibits the progression of CNV in an experimental animal model. These results suggest that axitinib could constitute a therapeutic alternative for the treatment of neovascular AMD.

Effect of cediranib, an inhibitor of vascular endothelial growth factor receptor tyrosine kinase, in a mouse model of choroidal neovascularization

Background:  This study was conducted to evaluate the effect of cediranib, an inhibitor of vascular endothelial growth factor receptor tyrosine kinase, in a mouse model of laser‐induced choroidal neovascularization.

Topically administered gold nanoparticles inhibit experimental corneal neovascularization in mice.

Purpose: The aim of this study was to evaluate the in vivo effects and mechanism of topically administered gold nanoparticles (AuNP) in a mouse model of corneal neovascularization. Methods: Inflammatory corneal neovascularization was induced by alkali burns, and the corneas were treated with topical AuNPs. After 1 week, the area of corneal neovascularization was measured using image analysis. The levels of vascular endothelial growth factor receptor 2 and extracellular signal-regulated kinase (ERK1/2) were evaluated by Western blotting. Results: The area of corneal neovascularization was significantly reduced by 39.8% in the AuNP group compared with the control group (P = 0.002). Corneal vascular endothelial growth factor receptor 2 level was higher in the control group than in the AuNP-treated group (P = 0.029). AuNP treatment similarly inhibited burn-induced phosphorylation of ERK (P = 0.029). Conclusions: Topical administration of AuNPs significantly reduced development of inflammatory corneal neovascularization by inhibiting the ERK pathway.

Exenatide reverses dysregulated microRNAs in high-fat diet-induced obese mice.

Exenatide has beneficial effects on insulin sensitivity in several animal models; however, its mechanism of action remains unclear. Furthermore, the relationship between the effect of exenatide on the changes in the relative abundance of microRNAs (miRNAs), which play a role in regulating glucose and lipid metabolism, is not fully understood. Therefore, we assessed the effect of exenatide on miRNA expression in a high-fat diet (HFD)-induced mouse model of obesity. Both HFD control and exenatide-treated HFD mice showed similar body weight gain and increase in β-cell mass. Insulin levels were significantly lower in exenatide-treated mice than in HFD control mice. The levels of miRNA-15a, 29c, 124a, and 375 in the pancreas were significantly increased in HFD control mice. Furthermore, the levels of miRNA-29c, 124a, and 146a in the liver and miRNA-15a, 29c, 124a, and 146a in the muscle were significantly increased. In contrast, the levels of miRNA-15a, 29c, 124a, and 375 in the serum were significantly decreased. These effects were reversed by treatment with exenatide. Our results provide experimental evidence that exenatide-mediated amelioration of insulin sensitivity is associated with antagonistic changes in the relative abundance of miRNA-15a, 29c, 124a, and 375 in tissues and serum, thus highlighting their usefulness as biomarkers for monitoring insulin sensitivity and response to exenatide treatment in experimental diabetes.

Microarrays for high‐throughput genotyping of MICA alleles using allele‐specific primer extension

The role of major histocompatibility complex (MHC) class I chain-related gene A (MICA), a ligand of NKG2D, has been defined in human diseases by its allele associations with various autoimmune diseases, hematopoietic stem cell transplantation (HSCT) and cancer. This study describes a practical system to develop MICA genotyping by allele-specific primer extension (ASPE) on microarrays. From the results of 20 control primers, strict and reliable cut-off values of more than 30,000 mean fluorescence intensity (MFI) as positive and less than 3000 MFI as negative, were applied to select high-quality specific extension primers. Among 55 allele-specific primers, 44 primers could be initially selected as optimal primer. Through adjusting the length, six primers were improved. The other failed five primers were corrected by refractory modification. MICA genotypes by ASPE on microarrays showed the same results as those by nucleotide sequencing. On the basis of these results, ASPE on microarrays may provide high-throughput genotyping for MICA alleles for population studies, disease-gene associations and HSCT.

Antiangiogenic Effects of Topically Administered Multiple Kinase Inhibitor, Motesanib (AMG 706), on Experimental Choroidal Neovascularization in Mice

PURPOSE To investigate the effect of topical motesanib, an inhibitor of receptor tyrosine kinase, on experimental choroidal neovascularization (CNV). METHODS CNV was induced in 46 nine-week-old male C57BL/6 mice using fundus laser photocoagulation. The right eye of each mouse was treated with motesanib eye drop (4 times daily) and the left eye with vehicle eye drop (4 times daily) for 14 days. To evaluate changes in the CNV lesions, fluorescein angiography, immunofluorescence staining with CD34, and histological examinations were performed 14 days after CNV induction. The expression of phosphorylated extracellular signal-regulated kinase (ERK1/2) in choroidal tissues was determined using western blot analysis to demonstrate the inhibitory effect of topically administered motesanib on intracellular signaling pathways involved in CNV development. RESULTS Fluorescein angiography showed that fluorescence leakage in eyes treated with topical motesanib was significantly less than in mice treated with vehicle (P=0.01). On immunofluorescence staining, the CD34-labeled area was smaller in topical motesanib-treated eyes (P<0.001). The expression level of phosphorylated ERK1/2 relative to that of total ERK1/2 decreased in eyes treated with topical motesanib compared with eyes treated with vehicle. CONCLUSION Topical motesanib significantly reduced laser-induced CNV in the experimental mouse model.

Identification and characterization of neurotrophic factors in porcine small intestinal submucosa

Abstract“Small intestinal submucosa” (SIS) is a natural degradable biomaterial derived from the small intestine of vertebrates. Porcine SIS has been widely used in repairing various tissues and organs, especially in nervous tissues because intrinsic autonomic nerve plexuses are included in submucosal layer. However, little is known about active neurotrophic factors in this material. In this study, we proposed a method to prepare an extract from decellularized SIS and to identify and characterize the major neurotrophic factors in it. Decellularized SIS extract was obtained by sequential procedures: mechanical disassociation, degreasing, enzyme digestion, freeze-drying, freezer-milling, extracting, concentrating, and filtering. Contamination with cellular components in the SIS extract was evaluated by hematoxylin and eosin (H&E) staining and the content of genomic DNA. Major neurotrophic factors in SIS extract was assessed quantitatively by ELISA. The effects of SIS extracts on cells were evaluated by observation of neurite outgrowth from PC12 cells. Decellularized SIS extract was obtained successfully by the proposed method and no cellular component was found within it. Brain-derived neurotrophic factor (BDNF), erythropoietin (EPO), glial cellderived neurotrophic factor (GDNF), nerve growth factor (NGF), and platelet-derived growth factor (PDGF) were identified and characterized form SIS extract. The bioactivity of SIS extract was assessed in terms of neurite outgrowth from PC12 cells. In summary, we prepared a decellularized extract from porcine SIS and identified major neurotrophic factors present in it. SIS extract also had bioactivity with PC12 cells. From these results, we conclude that SIS may be useful to repair or improve nervous system function.

Improved genotyping of the human minor histocompatibility antigen HB-1 by polymerase chain reaction with sequence-specific primers using a complementary oligonucleotide.

Single nucleotide polymorphisms of minor histocompatibility antigens (mHags) have been genotyped by allele-specific polymerase chain reaction with sequence-specific primers (PCR-SSP). Because discriminating the genotype of HB-1 Y by PCR-SSP under various PCR conditions was difficult, we optimized the use of oligonucleotides complementary to the allele-specific forward primer to improve the specificity of the HB-1 Y PCR-SSP. Specific allele discrimination was possible with an annealing temperature between 61°C and 63°C and in the presence of a threefold excess of a 15-bp complementary oligonucleotide. In conclusion, the inclusion of a complementary oligonucleotide in the PCR-SSP assay may improve its specificity and selectivity for genotyping several mHags for which optimizing PCR conditions have been difficult.

Corrigendum to “Paricalcitol Pretreatment Attenuates Renal Ischemia-Reperfusion Injury via Prostaglandin E2 Receptor EP4 Pathway”

[This corrects the article DOI: 10.1155/2017/5031926.].