Seong-Kyoon Choi

Improved neural progenitor cell proliferation and differentiation on poly(lactide‐co‐glycolide) scaffolds coated with elastin‐like polypeptide

Poly(lactide-co-glycolide) (PLGA) and elastin-like polypeptide (ELP) have been widely used as a biodegradable scaffold and thermoresponsive matrix, respectively. However, little attention has focused on the combinatorial use of these biomaterials for tissue engineering applications. An ELP matrix TGPG[VGRGD(VGVPG)6]20WPC (referred to as REP) contains multiple Arg-Gly-Asp motifs. This study fabricated porous PLGA scaffolds coated with various concentration of matrix via thermally induced phase transition to improve adhesion-mediated proliferation and differentiation of neural progenitor cells. Matrix-coated scaffolds were characterized by FTIR, SEM, and hematoxylin and eosin staining with respect to coating efficiency, porosity, and pore size and shape. On the matrix-coated scaffolds, cells grew as a single cell or associated each other to form a multicellular layer or cluster. In biological evaluations, cell adhesion and proliferation were significantly promoted in a matrix concentration-dependent manner. More importantly, in combination with retinoic acid, the differentiation of progenitor cells into neuronal and astroglial lineages was highly stimulated in the cells cultured on matrix-coated scaffolds than on untreated controls. Taken together, our results indicated that the REP matrix-functionalized PLGA scaffolds are suitable for improving neuronal cell functions, and thus applicable for neural tissue engineering.

Morphogenetic and neuronal characterization of human neuroblastoma multicellular spheroids cultured under undifferentiated and all-trans-retinoic acid-differentiated conditions

In this study, we aimed to compare the morphogenetic and neuronal characteristics between monolayer cells and spheroids. For this purpose, we established spheroid formation by growing SH-SY5Y cells on the hydrophobic surfaces of thermally-collapsed elastin-like polypeptide. After 4 days of culture, the relative proliferation of the cells within spheroids was approximately 92% of the values for monolayer cultures. As measured by quantitative assays for mRNA and protein expressions, the production of synaptophysin and neuronspecific enolase (NSE) as well as the contents of cell adhesion molecules (CAMs) and extracellular matrix (ECM) proteins are much higher in spheroids than in monolayer cells. Under the all-trans-retinoic acid (RA)-induced differentiation condition, spheroids extended neurites and further up-regulated the expression of synaptophysin, NSE, CAMs, and ECM proteins. Our data indicate that RA-differentiated SH-SY5Y neurospheroids are functionally matured neuronal architectures. [BMB Reports 2013; 46(5): 276-281]

Integrin-binding elastin-like polypeptide as an in situ gelling delivery matrix enhances the therapeutic efficacy of adipose stem cells in healing full-thickness cutaneous wounds

One crucial issue in stem cell therapy used for tissue repair is often the lack of selective carriers to deliver stem cells to the site of injury where the native extracellular matrix is pathologically damaged or lost. Therefore, it is necessary to develop a biomaterial that is permissive to stem cells and is suitable to replace injured or missing matrix. The major aim of this study is to investigate the potential of an RGD-containing elastin-like polypeptide (REP) with the structure TGPG[VGRGD(VGVPG)6]20WPC to engraft adipose stem cells (ASC) to full-thickness excisional wounds in mice. We implanted REP into the wound defects via body temperature-induced in situ aggregation. Engrafted REP exhibited a half-life of 2.6days in the wounds and did not elicit any pathological immune responses. REP itself significantly accelerated wound closure and reepithelialization and upregulated the expression of dermal tissue components. A combined administration of REP and ASC formed a hydrogel-like ASC/REP composite, which provided better neovascularization than the use of ASCs alone and increased the viability of transplanted ASC, improving overall wound healing. In vitro and in vivo mechanistic investigations suggested that REP enhances ASC survival at least in part via the Fak/Src adhesion-induced upregulation of Mek/Erk and PI3K/Akt survival pathways. We conclude that REP is a promising therapeutic agent for the improvement of stem cell-based therapy for enhanced tissue regeneration and repair.

A new selective ‘turn-on’ small fluorescent cationic probe for recognition of RNA in cells

Fluorescent imaging probes have revolutionised cell biology by monitoring cellular objects. However, the lack of fluorescent probes with high selectivity for RNA has been a drawback. Thus, selective RNA binding for fluorescent sensors is essential. Here, we report the selective fluorescence enhancement upon addition of RNA. By exploiting a selective recognition of small tetra-cationic probe 1 for RNA, we also explain the possible binding mode for RNA. As a membrane-permeant fluorescence probe, 1 provides selective imaging of RNA not only in human neuroblastoma tumour SH-SY5Y cell line used for Parkinsons disease but also in the unicellular green alga cells. Further exploitation could open new opportunities in neurotoxin and cancer biology.

The Evolutionarily Conserved LIM Homeodomain Protein LIM-4/LHX6 Specifies the Terminal Identity of a Cholinergic and Peptidergic C. elegans Sensory/Inter/Motor Neuron-Type

The expression of specific transcription factors determines the differentiated features of postmitotic neurons. However, the mechanism by which specific molecules determine neuronal cell fate and the extent to which the functions of transcription factors are conserved in evolution are not fully understood. In C. elegans, the cholinergic and peptidergic SMB sensory/inter/motor neurons innervate muscle quadrants in the head and control the amplitude of sinusoidal movement. Here we show that the LIM homeobox protein LIM-4 determines neuronal characteristics of the SMB neurons. In lim-4 mutant animals, expression of terminal differentiation genes, such as the cholinergic gene battery and the flp-12 neuropeptide gene, is completely abolished and thus the function of the SMB neurons is compromised. LIM-4 activity promotes SMB identity by directly regulating the expression of the SMB marker genes via a distinct cis-regulatory motif. Two human LIM-4 orthologs, LHX6 and LHX8, functionally substitute for LIM-4 in C. elegans. Furthermore, C. elegans LIM-4 or human LHX6 can induce cholinergic and peptidergic characteristics in the human neuronal cell lines. Our results indicate that the evolutionarily conserved LIM-4/LHX6 homeodomain proteins function in generation of precise neuronal subtypes.

Molecular Genetic Diversity of the Gyeongju Donggyeong Dog in Korea

ABSTRACT The present study was conducted to analyze the genetic characteristics of the Donggyeong dog and establish parentage conservation systems for it by using 10 microsatellite markers recommended by the International Society for Animal Genetics (ISAG). A total of 369 dogs from 12 dog breeds including the Donggyeong dog were genotyped using 10 microsatellite loci. The number of alleles per locus varied from 5 to 10 with a mean value of 7.6 in the Donggyeong dog. The observed heterozygosity and expected heterozygosity ranged from 0.4706 to 0.9020 (mean 0.7657) and from 0.4303 to 0.8394 (mean 0.7266), respectively. The total exclusion probability of 10 microsatellite loci was 0.99955. Of the 10 microsatellite markers, the AHT121, AHTh260 and CXX279 markers had relatively high PIC values (≥0.7). This study found that there were specific alleles, 116 allele at AHT121 in the Donggyeong dog when compared with other dog breeds. Also, the results showed two (Korean native dogs and the foreign dog breeds) distinct clusters. The closest distance (0.1184) was observed between the Donggyeong dog and Jindo dog, and the longest distance (0.3435) was observed between the Donggyeong dog and Bulgae. The Korean native dog breeds have comparatively near genetic distances between each other.

Cytotoxicity and inhibition of intercellular interaction in N2a neurospheroids by perfluorooctanoic acid and perfluorooctanesulfonic acid

Effects of perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) on the neuronal lineage marker expression, cell-cell interaction, caspase-3 mRNA transcription and reactive oxygen species production by N2a neuronal cells were assesses in 3-dimensional (3D) spheroid cultures, and the cytotoxicity were thoroughly compared with those of a conventional 2D monolayer-based toxicity assay. Increasing concentrations of PFOA or PFOS resulted in an increase in cell death. The half maximal inhibitory concentrations measured with spheroids were approximately one and a half times greater than the respective values for monolayer cells. Necrosis was prevalent in spheroids regardless of the dose, whereas the major injury mechanism in monolayers was dependent on compound concentration. Both PFOA and PFOS inhibited neuronal, astrocyte and oligodendrocyte marker gene expression by monolayers and spheroids grown under undifferentiated and all-trans-retinoic acid-induced differentiating conditions. In the presence of PFOA or PFOS, expression levels of E-cadherin and connexin-43 mRNAs were significantly downregulated, and spheroids were dissociated into single cell populations, indicating that the compounds affect the synthesis of E-cadherin and connexin-43 at the transcriptional level. Results from 3D cultures may provide an insight into potential inhibitory mode of action on gap junctional intercellular communication.

Reverse Expression of Aging-Associated Molecules through Transfection of miRNAs to Aged Mice

Molecular changes during aging have been studied to understand the mechanism of aging progress. Herein, changes in microRNA (miRNA) expression in the whole blood of mice were studied to systemically reverse aging and propose them as non-invasive biomarkers. Through next-generation sequencing analysis, we selected 27 differentially expressed miRNAs during aging. The most recognized function involved was liver steatosis, a type of non-alcoholic fatty liver disease (NAFLD). Among 27 miRNAs, six were predicted to be involved in NAFLD, miR-16-5p, miR-17-5p, miR-21a-5p, miR-30c-5p, miR-103-3p, and miR-130a-3p; alterations in their blood and liver levels were confirmed by real-time qPCR. The expression of the genes associated in the network of these miRNAs, Bcl2, Ppara, E2f1, E2f2, Akt, Ccnd1, and Smad2/3, also was altered in the liver of aged mice. Following transfection of these miRNAs into 18-month-old mice, levels of miR-21a-5p, miR-103-3p, and miR-30c-5p increased, and their related genes exhibited a reversed expression in the liver. Expression of Mre11a, p16INK4a, and Mtor, reported to be aging-associated molecules, also was reversed in the livers of miRNA-transfected mice. These miRNAs could be non-invasive biomarkers for aging, and they might induce a reverse regulation of aging-associated pathways. This study provides preliminary data on reverse aging, which could be applied further for treatments of adult diseases.

Characteristics and Antimicrobial Susceptibility Patterns of Pasteurella multocida Isolated from Pneumonic Lung Lesions of Swine

The present study was conducted to investigate the species-specific gene detection and antimicrobial susceptibility of Pasteurella (P.) multocida isolated from pneumonic lung lesions of Youngnam swine herds during the period from July 2006 to September 2007. A total of 91 (36.3%) strains of P. multocida were isolated from 251 pneumonic lung lesions. The species-specific P. multocida gene was detected at 460 bp amplicons by PCR. The P. multocida tested was susceptible to florofenicol (93.4％), amikacin (91.2％), cephalothin (87.9％), cefoxitin (84.6％), ofloxacin (80.2％) and norfloxacin (65.9％) in 27 antimicrobial susceptibility tests. Most of strains were resistant to more than 5 drugs.

Three-dimensional multicellular neurospheroids for neurological assessment of neurotoxic compounds

This research was designed to determine if veterans with mild Traumatic Brain Injury (TBI) show neuropsychological deficits in any of a number of areas (e.g., executive functions, memory). Independent groups, mild TBI (n=57) and control (n=57), were administered seven measures of cognitive functioning, five that are associated with executive processes and two that are associated with potential global dysfunction. Participants also completed four other psychological measures to gain information on aspects such as depressive symptoms, combat exposure, effort, and self-awareness of deficits. Demographic data such as age, ethnicity, marital status, and medications was also gathered. It was anticipated that the mild TBI group administration results would be worse on the executive measures and about the same or better than that of the control group on the other measures. Mild TBI group performed significantly worse on all of the 11 executive functions measurements except Category Fluency (p = .077), after controlling for Age, Depression, Word Memory Test scores, and Combat Exposure. Curiously, the Mild TBI group performed significantly poorer on all of the three non-executive neuropsychological measurements. Post hoc analysis, adding the non-executive tasks to the covariates, rendered two of the variables (Rey Immediate Recall and Rey Copy Time) no longer significant. The majority of mild TBI participants had good insight and awareness of the extent of their deficits (Mean = 4.9, SD = 2.86). Although technically the mild TBI scored more in the poor effort direction on each of the tests (sign test, p = .016), only one of the differences, for Multiple Choice, proved to be significant, and this difference accounted for only 4% of the variance.To date there is very few clinical studies published on the cognitive characteristics in patients with SCA3 in China, we sought to evaluate the cognitive function in a cohort of clinically diagnosed and molecularly confirmed patients with SCA3 in China. The neuropsychological tests that were used to evaluate the cognitive function consisted of the Mini-Mental State Examination (MMSE), Clock Drawing Test (CDT), Digit Cancellation Test (DC), Digit Symbol Substitution Test (DSST), Stroop Color-Word Test (SCWT), Trial-Making Test (TMT), Verbal Fluency Test (VFT), and Wechsler Intelligence Scale-Digit Span Test (WISC-DST). The psychiatric symptoms were assessed by the Hamilton Anxiety Scale (HAMA) and Hamilton Depression Scale (HAMD). The severity of motor symptoms was evaluated by the Scale for the Assessment and Rating of Ataxia (SARA). 15 patients with genetically confirmed SCA3 and 15 normal control subjects were enrolled in the study. There was no significant difference in age, gender or educational level among these 2 groups. CDT, DC, DSST, SCWT, TMT, VFT were significantly more impaired in patients with SCA3 than those in the control group. There was no significant difference in the MMSE, DST, HAMA and HAMD between SCA3 patients and controls. In conclusion, our study demonstrates that patients with SCA3 in China present cogintive impairments, manifesting mainly as executive and visuospatial dysfunction. (Ruihao Wang, Song Tan, Bo Song, Jingtao Wang, Fang Ge, Shilei Sun, Wang Miao, Jun Wu, Limei Wang, Rui Zhang, Yuan Gao, Huixia Niu, Changhe Shi, Hui Fang, Avinash Chandra, Yuming Xu. Cognitive Impairments in Patients with Spinocerebellar Ataxia Type 3 (SCA3) in China. Life Sci J. 2013;10(1):1655-1659) (ISSN:1097-8135). http://www.lifesciencesite.com. 243R scale initially developed to predict the recurrence risk of stroke by the American Academy of Neurology was found to be able to predict the short-term risk of stroke in patients with transient symptom with infarction (TSI). However, this scale was just applied to predict short-term prognosis in patients with TSI in 2011, and it is necessary to verify its validity and reliability in different races and populations. The aim of this study was to evaluate the accuracy of the RRE-90 scale to predict the short-term risk of stroke after TSI in a Chinese population. Data were prospectively collected from the Department of Neurology and emergency department of the First Affiliated Hospital of Zhengzhou University. RRE score was available within 7 days after onset. The predictive outcome was stroke occurrence at 7 days. The receiver-operating characteristic curves were plotted, and the C statistics were calculated as a measure of predictive ability. The cut-off point was determined, cut-off point for predictive value of subsequent stroke was analyzed. Eighty consecutive TSI patients were prospectively enrolled, the mean age was 60.20±11.42 years, and 32% of them were women. The best cut-off point was 3. The incidence of stroke at 7 days was 20%, which ranged from 5.8% in patients with lower RRE-90 scores (0-2) to 46.4% in those with higher scores of 3 to 6. The C statistic of RRE-90 score was 0.839 (95% CI ) at 7 days. We concluded that RRE-90 scale was able to assess the risk of early stroke after TSI in a Chinese population. Hui Fang, J Neurol Neurophysiol 2013, 4:3 http://dx.doi.org/10.4172/2155-9562.S1.014A vast majority of studies evaluating interactions between antiepileptic and nonantiepileptic drugs are based on their single administration, whereas epileptic patients require chronic pharmacotherapy. The aim of this study was to evaluate the effect of repeated administration of valproate on its anticonvulsant action, neurological adverse effects, therapeutic index, as well as plasma and brain concentrations. The anticonvulsant effect was estimated in the maximal electroshock test in mice. The antiepileptic was applied in four protocols: once a day for one week (1x1), twice a day for one week (1x2), once a day for two weeks (2x1), and twice a day for two weeks (2x2). Single administration of valproate served as a control. The ED50 (50% effective dose) of valproate given in the 2x2 protocol was significantly lower than the control value. No significant differences were found in three remaining administration protocols. Serum and brain concentrations of valproate were not altered during chronic treatment with this drug. Moreover, no significant deficit in memory was observed after repeated valproate administration in the passive-avoidance task. In contrast, TD50s (50% toxic doses) evaluated for chronic valproate in the chimney were significantly lower than the control. Therapeutic indices (TIs) of this drug calculated in chronic protocols (1x1, 1x2, 2x1, and 2x2) were respectively 1.48, 1.39, 1.38 and 1.89. Summing up, repeated administration can change both effectiveness and toxicity of valproate. This effect does not seem to be dependent on pharmacokinetic events. To increase reliability of results obtained in animal models, antiepileptic drugs should be administered chronically.Study Design: Mixed method, experimental design Objective: The purpose of this study is to analyze the changes in force distribution of hippo therapy participants who are seated atop a pressure sensing system. Methods: The subjects are students enrolled in a doctoral PT program who volunteered to participate in therapeutic riding simulations. The students will be randomly assigned to a riding style (either bareback, western, or English). Changes in force distribution patterns will be measured utilizing a force distribution sensing system laid atop a saddle. The sensing system will be connected to a lap-top computer and secured to the horse in a vented saddle-bag. Visual analog graphs that are derived from the force distribution mat will be compared and contrasted for each student, riding style, and amount of time spent riding. Results: The sensor data obtained will be compared for the three riding styles and evaluated in relationship to therapeutic riding goals for patients with neuromuscular and postural control impairments. Cristy Phillips, J Neurol Neurophysiol 2013, 4:3 http://dx.doi.org/10.4172/2155-9562.S1.014