• Biotechnology and Bioprocess Engineering:BBE
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• 제6권4호
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• pp.205-212
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• 2001

One of the important characteristics of biological systems os their ability to change im-portant properties in response to small environmental signals. The molecular mechanisms that biological molecules utilize to sense and respond provide interesting models for the development of "smart" polymeric biomaterials with biomimetic properties. An important example of this is the protein coat of viruses, which contains peptide units that facilitate the trafficking of the virus into the cell via endocytosis, then out of the endosome into the cytoplasm, and from there into the nucleus, We have designed a family of synthetic polymers whose compositions have been de-signed to mimic specific peptides on viral coats that facilitate endosomal escape. Our biomimetic polymers are responsive to the lowered pH whinin endosomes, leading to distruption of the en-dosomal membrane and release of important biomolecular druges such as DNA, RNA, peptides and proteins to the cytoplasm before they are trafficked to lysosomes and degraded by lysosomal en-zymes. In this article, we review our work on the design, synthesis and action of such smart, pH-sensitive polymers.

• Journal of Microbiology and Biotechnology
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• 제26권9호
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• pp.1613-1619
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• 2016

Francisella tularensis is a highly virulent pathogen of humans and other mammals. Moreover, F. tularensis has been designated a category A biothreat agent, and there is growing interest in the development of a protective vaccine. In the present study, we determine the in vitro and in vivo immune responses of a subunit vaccine composed of recombinant peptides Tul4 and FopA from epitopes of the F. tularensis outer membrane proteins. The recombinant peptides with adjuvant CpG induced robust immunophenotypic change of dendritic cell (DC) maturation and secretion of inflammatory cytokines (IL-6, IL-12). In addition, the matured DCs enabled ex vivo proliferation of naive splenocytes in a mixed lymphocyte reaction. Lastly, we determined the in vivo immune response by assessment of antibody production in C57BL/6 mice. Total IgG levels were produced after immunization and peaked in 6 weeks, and moreover, Tul4-specific IgG was confirmed in the mice receiving peptides with or without CpG. Based on these results, we concluded that the recombinant peptides Tul4 and FopA have immunogenicity and could be a safe subunit vaccine candidate approach against F. tularensis.

• Asian Pacific Journal of Cancer Prevention
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• 제14권12호
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• pp.7095-7100
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• 2013

Histone deacetylase (HDAC) inhibitors of cyclic peptide have been proved to be the most complex but the most stable and relative efficient inhibitors because of their large cap region. In this paper, a series of studies were carried out to evaluate the efficacy of synthetic bicyclic tetrapeptide inhibitors 1-5 containing hydroxamic acid referring molecular docking, anti-proliferation, morphology and apoptosis. Docking analysis, together with enzyme inhibitory results, verified the selective capability of inhibitor 4 to HDAC4, which might closely related to haematological tumorigenesis, with Phe227, Asp115, Pro32, His198 and Ser114 participating into hydrophobic interactions and Van der Waals force which was familiar with former study. Moreover, inhibitor 4 inhibited K562 cell line at the $IC_{50}$ value of 1.22 ${\mu}M$ which was 51-67 times more efficient than that for U937 and HL60 cell lines. Inhibitor 4 exhibited the cell cycle-arrested capability to leukemia at S phase or G2/M phase as well as apoptosis-induced ability in different degrees. Finally, we considered that bicyclic tetrapeptide inhibitors were promising inhibitors used in cancer treatment and inhibitor 4 could prevent K562 cell line well from proliferation, arrest cell cycle and induce K562 towards apoptosis to achieve the goals of reversing cancer cells which could become a potential leukemia therapeutic agent in the future.

• Journal of Microbiology and Biotechnology
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• 제8권4호
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• pp.369-377
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• 1998

Rotavirus is a major cause of severe gastroenteritis in young children and animals throughout the world. The VP7 of rotavirus is thought to induce the synthesis of neutralizing antibodies and to be responsible for determining viral serotypes. The cDNA coding for the VP7 capsid protein of human rotavirus, obtained from Korean patients (HRV-Y14), was cloned and its nucleotide sequence was determined. Comparative analysis of the nucleotide sequences between VP7 of Y14 and that of other foreign isolates showed $92.7~95.2\%$ homology to G1 serotypes (RV-4, KU, K8, WA), $74.2\%$ homolgy to G2 serotype HU-5, $76.4\%$ homology to G3 serotype SA-11, and $77.6\%$ homology to G4 serotype A01321. These data suggest that HRV-Y14 can be classified as a G1 serotype. cDNA coding for VP7 of HRV-YI4 was subcloned into the baculovirus vector and the VP7 glycoprotein was expressed in insect cells. The expressed proteins in Sf9 cell extract and tissue culture fluid were separated on SDS-PAGE, and Western blot analysis with monoclonal antibody raised against the synthetic peptide containing 21 amino acids within the VP7 conserved region was performed. The molecular weight of recombinant VP7 was estimated to be 36 kDa which is about the same size as the native VP7. Addition of tunicamycin in the culture media caused a reduction of the molecular weight of the recombinant VP7 indicating that the expressed protein was glycosylated.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.268-268
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• 2006

Due to their multipotency, stem cells can differentiate into a variety of specialized cell types, such as chondrocytes, osteoblasts, myoblasts, and nerve cells. As an alternative to mature tissue cells, stem cells are of importance in tissue engineering and regenerative medicine. Since interactions between scaffold and cells play an important role in the tissue development in vitro, synthetic oligopeptides have been immobilized onto polymeric scaffolds to improve specific cell attachment and even to stimulate cell differentiation. In this study, chondrogenic differentiation of stem cells was evaluated using surface-modified PLLA scaffolds, i.e., either hydrophilic acrylic acid (AA)-grafted PLLA or RGD-immobilized one. Porous PLLA scaffolds were prepared using a gas foaming method, followed by plasma treatment and subsequent grafting of AA to introduce a hydrophilicity (PLLA-PAA). This was further processed to fix RGD peptide to make an RGD-immobilized scaffold (PLLA-PAA-RGD). Stem cells were seeded at $1{\times}10^{6}$ cells per scaffold and the cell-PLLA constructs were cultured for up to 4 weeks in the chondrogenic medium. Using these surface-modified scaffolds, adhesion, proliferation, and chondrogenic differentiation of stem cells were evaluated. The surface of PLLA scaffolds turned hydrophilic (water contact angle, 45 degrees) with both plasma treatment and AA grafting. The hydrophilicity of RGD-immobilized surface was not significantly altered. Cell proliferation rate on the either PLLA-PAA or PLLA-PAA-RGD surface was obviously improved, especially with the RGD-immobilized one as compared to the control PLLA one. Chondrogenic differentiation was clearly identified with Safranin O staining of GAG in the AA- or RGD-grafted PLLA substrates. This study demonstrated that modified polymer surfaces may provide better environment for chondrogenesis of stem cells.

• 대한의생명과학회지
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• 제19권1호
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• pp.41-47
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• 2013

Pluripotent stem cells (PSCs) have lots of potential in biomedical sciences owing to its potential to differentiate into any kind of cells in the body. However, it is still a challenge to culture PSCs on a large scale for application to regenerative medicine. Herein, we introduce a synthetic polymer that enables large-scale suspension culture of human PSCs. By employing suspension culture, it became unnecessary to use conventional substrata such as mouse embryonic fibroblast (MEF) or Matrigel$^{TM}$, which are believed to be main causative sources of xenogeneic contamination in cultured human PSCs in vitro. Human PSCs were cultured in the medium in which elastin-like polypeptide (ELP) dissolved. The ELP in the medium became harden as temperature increases by transforming the medium into a semi-solid gel that supported growth of human PSCs in suspension. Gel-sol transition temperature of ELP can be adjusted by modifying the peptide sequence in which 5 amino acids, Val-Pro-Gly-Xaa-Gly, repeated sequentially. We constructed 3D suspension media having transition temperature around $33{\sim}35^{\circ}C$ using an ELP consisted of 40, 60, or 80 repeats of a monomer, which was Val-Pro-Gly-Val-Gly. Among the ELPs, ELP80 was chosen as the best ELP to support growth of human PSCs in suspension culture. This result suggests that the ELP80 can be a medium component for culturing human PSCs in large-scale.

• 생명과학회지
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• 제22권1호
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• pp.25-30
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• 2012

TSLP 유전자는 IL-7와 유사한 새로운 조혈성 사이토카인이다. 인간의 TSLP는 상피세포, 기질세포 및 비만세포에서 만들어진다. TSLP는 류마티스관절염 환자의 윤활성 활액에서 높은 발현을 나타낸다. 이전 연구에서 우리들은 사람의 TSLP유전자에서 4개의 유전자다형성 및 한 개의 변이를 발굴하였다. 이 연구에서는, 우리들이 발굴한 TSLP유전자의 유전자다형성의 유전자형 및 대립형질의 비율을 건강한 정상인과 류마티스관절염 환자에서 비교분석하였으며, 류마티스관절염 환자에 있어서 유전자형에 따른 RF 및 anti-CCP의 정도를 비교 분석하였다. 또한, 양쪽 그룹에서 이들 유전자다형성에 의한 일배체형 비율을 비교 분석하였다. 그 결과, 류마티스관절염 환자군과 건강한 정상인 군 사이에 있어서 유전자형, 대립형질 비율뿐만 아니라 일배체형 비율에 큰 차이를 보이지 않았다. 이 결과는 TSLP유전자의 유전자다형성은 류마티스관절염 감수성에 영향을 미치지 않음을 암시한다.

• 약학회지
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• 제41권2호
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• pp.247-254
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• 1997

The proteinase-activated receptor (PAR-2) belongs to the family of seven transmembrane region receptors, like the thrombin receptor, it is activated by specific proteolytic clea vage of its extracellular amino terminus and a synthetic peptide (SLIGRL). The earthworm protein fraction (EPF) extracted from Lumbricus rubellus elicted dose- and endothelium-dependent relaxations in phenylephrine-contracted rat thoracic aorta, whereas heat inactivated EPF (0.5 ${\mu}g$ /ml) had no effect. In the presence of the nitric oxide synthase inhibitor NG-methyl-L-arginine (1.8 micro M), EPF (0.5 ${\mu}g$ /ml)-induced relaxations were partially inhibited. Furthermore, EPF (0.5 ${\mu}g$ /ml) dramatically caused relaxation of thrombin-desenstized rat thoracic aorta. These results indicate that EPF activates PAR-2 in vascular endothelial cell. Intravenous injection of EPF (20 mg/kg, bolus) into anesthetized rats produced a marked depressor response. EPF (0 ~ 80 ${\mu}g$ /ml, gradient) was very effective on increasing of perfusion volume in rabbit ear vessel preparations. These results imply the usefulness of EPF as a vascular smooth muscle relaxant and indicate that the activation of PAR-2 may be a mechanism of EPF on hemokinetic improvement.

• Asian-Australasian Journal of Animal Sciences
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• 제11권6호
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• pp.725-731
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• 1998

Nine crossbred female pigs fitted with the bladder catheters were used to investigate the effects of dietary protein form on the efficiency of absorbed nitrogen for nitrogen retention in growing pigs. Combinations of the main protein sources were corn-soybean meal (CSM; slow + slow absorption rate form), corn-hydrolyzed casein (CAS; slow + rapid absorption rate form) and corn-porcine plasma (CPL; slow + intermediate absorption rate form). All experimental diets were formulated to be isonitrogenous (CP 11%) and isocaloric (3.5 Mcal/kg) and synthetic amino acids were added to the diet as required to maintain an equivalent amino acid profile among diets. Fecal digestibility of nitrogen was not different among treatments (p > 0.10). Ingested nitrogen was absorbed with an apparent efficiency of 82% to 84%. Mean nitrogen retention in pigs fed the CSM diet was as high as for pigs fed the CPL diet (0.74 g N/kg $BW^{0.75}$ per d), which was higher than the N retention rate in pigs fed CAS diet (0.68 g/kg $BW^{0.75}$ per d; P < 0.05). Apparent biological values (ABV = 100 ${\times}$ N retention/absorbed nitrogen) were 63.3%, 58.0% and 61.6% for CSM, CAS, and CPL groups, respectively (p < 0.05). There was no difference in mean energy digestibility among treatments. The efficiency of absorbed lysine utilization was significantly different among treatments (p < 0.05). Pigs fed the CAS diet were inferior to counterparts on the other diets in utilizing absorbed lysine. The ratios of free (and small peptide-bound) to protein-bound amino acids in CSM diet differed considerably from the CAS diet. This may affect the efficiency of amino acids utilization for nitrogen retention if hydrolyzed and intact amino acid pools reach the blood at different times.

• BMB Reports
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• 제38권4호
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• pp.386-390
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• 2005

Based on the reported cDNA sequences of $BmK{\alpha}Txs$, the genes encoding toxin $BmK{\alpha}Tx11$ and $BmK{\alpha}Tx15$ were amplified by PCR from the Chinese scorpion Buthus martensii Karsch genomic DNA employing synthetic oligonucleotides. Sequences analysis of nucleotide showed that an intron about 500 bp length interrupts signal peptide coding regions of $BmK{\alpha}Tx11$ and $BmK{\alpha}Tx15$. Using cDNA sequence of $BmK{\alpha}Tx11$ as probe, southern hybridization of BmK genome total DNA was performed. The result indicates that $BmK{\alpha}Tx11$ is multicopy genes or belongs to multiple gene family with high homology genes. The similarity of $BmK{\alpha}$-toxin gene sequences and southern hybridization revealed the evolution trace of $BmK{\alpha}$-toxins: $BmK{\alpha}$-toxin genes evolve from a common progenitor, and the genes diversity is associated with a process of locus duplication and gene divergence.