Osterix plays a critical role in BMP4-induced promoter activity of connexin43

( Younho Han ),( Dong Hyeok Cho ),( Dong Jin Chung ),( Kwang Youl Lee ) 전남대학교 약품개발연구소 2016 약품개발연구지 Vol.25 No.-

Osterix is an essential transcription factor for osteogenesis and is expressed in osteoblasts. Although Osterix has been shown to be induced by bone morphogenetic protein 4, the molecular mechanism underlying Osterix function during osteoblast differentiation remains unclear. Connexin43 (Cx43) is the most abundant gap junction protein in bone cells and plays a critical role in osteoblast differentiation. However, little is known about the functional interactions between Osterix and the Cx43 promoter. In the present study, we investigated the relationship between Osterix and Cx43 in HEK293 and C2C12 cells. Cx43 expression was significantly repressed by the addition of shRNA against Osterix, whereas over- expression of Osterix resulted in enhanced Cx43 expression. Furthermore, Osterix directly occupied the promoter region of Cx43 and subsequently increased Cx43 promoter activity in a dose-dependent manner. In addition, phosphorylation of the Ser76 and Ser80 residues in Osterix were found to be critical for its activity on the Cx43 promoter. Our results suggest that Osterix plays an important role in increasing bone morphogenetic protein 4-induced Cx43 activity. ⓒ 2016 Elsevier Inc. All rights reserved.

Variable Angle Beam Guided Wave Probe Design for Tubing Based on Solid Mechanics

Younho Cho 한국비파괴검사학회 2003 한국비파괴검사학회지 Vol.23 No.6

Discovery and characterization of berberine derivatives as stimulators of osteoblast differentiation

Younho Han,Won-Jong Park 대한구강생물학회 2019 International Journal of Oral Biology Vol.44 No.4

Berberine has been used clinically for more than a decade to treat various diseases, has been shown to be effective in osteoblast differentiation, and is a potential treatment option for osteoporosis. However, compared with existing osteoporosis drugs, berberine is somewhat less effective. This study aimed to identify a new compound with efficacy superior to that of berberine. The osteogenic activities of various berberine derivatives were evaluated via cell differentiation in C2C12 preosteoblast cell lines. Alkaline phosphatase (ALP) staining assay and structure– activity relationship demonstrated that compound 2b had a potent osteogenic effect. Furthermore, compound 2b dose dependently increased ALP activity and showed no toxicity at the effective concentration, indicating its efficacy. Additionally, compound 2b upregulated BMP2-induced transcriptional activity in a promoter activity assay using ALP, BSP, and OC promoters.

Potential candidate biomass for bioenergy production

Younho Song,Nguyen Thi Minh Thu,Gahui Gwak,Hyeun-Jong Bae 한국에너지학회 2017 한국에너지공학회 학술발표회 Vol.2017 No.4

The Regulatory Effects of Trans-chalcone on Adipogenesis

Younho Han 대한구강생물학회 2018 International Journal of Oral Biology Vol.43 No.1

It is noted that chalcone derivatives have characteristic diverse pharmacological properties, and that precise evidence has been growing that they could regulate a tumor necrosis factor-α (TNF-α) induced insulin resistance. The purpose of the present investigation is to elucidate the effects of the identified chalcone derivatives on adipogenesis, and to find the underlying mechanism of action in that case. Consequently, we first investigated whether the chalcone derivatives could affect the identified PPARγ-induced transcriptional activity on the proliferator-activated receptor response elements (PPRE) at target promoters, and find that trans-chalcone most significantly increased the PPARγ -induced transcriptional activity. Additionally, we confirmed that there were up-regulatory effects of trans-chalcone during the adipogenesis and lipid accumulation, and on the mRNA of adipogenic factors in 3T3-L1 cells. Next, we examined the effect of trans-chalcone on the inhibition induced by TNF-α on adipogenesis. To that end, we noted that the treatment with trans-chalcone attenuated the effect of TNF-α mediated secretion of various adipokines that are involved in insulin sensitivity. For this reason, we noted that this study clearly demonstrates that trans-chalcone enhanced adipogenesis, in part, by its potent effect on PPARγ activation and by its reverse effect on TNF-α.

A Numerical Analysis on Elastodynamic Dispersion Phenomena of Composite Pipes

Younho Cho,Chong Myong Lee,Joseph L. Rose 한국비파괴검사학회 2005 한국비파괴검사학회지 Vol.25 No.3

Pin1 enhances adipocyte differentiation by positively regulating the transcriptional activity of PPARγ

( Younho Han ),( Sung Ho Lee ),( Minjin Bahn ),( Chang-yeol Yeo ),( Kwang Youl Lee ) 전남대학교 약품개발연구소 2016 약품개발연구지 Vol.25 No.-

Pin1 is a peptidylprolyl cis/trans isomerase and it has a unique enzymatic activity of catalyzing isom-erization of the peptide bond between phospho-serine/threonine and proline. Through the conforma-tional change of its substrates, Pin1 regulates diverse biological processes including adipogenesis. In mouse embryonic fibroblasts and 3T3-L1 preadipocytes, overexpression of Pin1 enhances adipocyte differentiation whereas inhibition of Pin1 activity suppresses it. However, the precise functions of Pin1 during adipogenesis are not clear. In the present study, we investigated the potential targets of Pin1 during adipogenesis. We found that Pin1 interacts directly with and regulates the transcriptional activity of PPARγ, a key regulator of adipogenesis. In addition, ERK activity and Ser273 of PPARγ, a potential ERK phosphorylation target site, are important for the regulation of PPARγ function by Pin1 3T3-L1 cells. Taken together our results suggest a novel regulatory mechanism of pin1 during adipogensis. In which Pin1 enhances adipocyte differentiation by regulating the function of PPARΥ. ⓒ 2016 Elsevier lreland Ltd. All rights reserved.

Osterix represses adipogenesis by negatively regulating PPARγ transcriptional activity

( Younho Han ),( Chae Yul Kim ),( Heesun Cheong ),( Kwang Youl Lee ) 전남대학교 약품개발연구소 2016 약품개발연구지 Vol.25 No.-

Osterix is a novel bone-related transcription factor involved in osteoblast differentiation, and bone maturation. Because a reciprocal relationship exists between adipocyte and osteoblast differentiation of bone narrow derived mesenchymal stem cells, we hypothesized that Osterix might have a role in adipogenesis. Ablation of Osterix enhanced adipogenesis in 3T3-L1 cells, whereas overexpression suppressed this process and inhibited the expression of adipogenic markers including CCAAT/enhancer-binding protein alpha(C/EBPα) and peroxisome proliferator-activated receptor gamma(PPARγ). Further studies indicated that Osterix significantly decreased PPARγ-induced transcriptional activity. Using co-immunoprecipitation and GST-pull down analysis, we found that Osterix directly interacts With PPARγ. The ligand-binding domain(LBD)of PPARγ was responsible for this interaction, which was followed by repression of PPARγ-induced transcriptional activity, even in the presence of rosiglitazone. Taken together, we identified the Osterix has an important regulatory role on PPARγ activity, which contributed to the mechanism of adipogenesis.

Plasmid-Encoded MCP Is Involved in Virulence, Motility, and Biofilm Formation of <i>Cronobacter sakazakii</i> ATCC 29544

Choi, Younho,Kim, Seongok,Hwang, Hyelyeon,Kim, Kwang-Pyo,Kang, Dong-Hyun,Ryu, Sangryeol American Society for Microbiology 2015 Infection and immunity Vol.83 No.1

<P>The aim of this study was to elucidate the function of the plasmid-borne <I>mcp</I> (methyl-accepting chemotaxis protein) gene, which plays pleiotropic roles in <I>Cronobacter sakazakii</I> ATCC 29544. By searching for virulence factors using a random transposon insertion mutant library, we identified and sequenced a new plasmid, pCSA2, in <I>C. sakazakii</I> ATCC 29544. An <I>in silico</I> analysis of pCSA2 revealed that it included six putative open reading frames, and one of them was <I>mcp</I>. The <I>mcp</I> mutant was defective for invasion into and adhesion to epithelial cells, and the virulence of the <I>mcp</I> mutant was attenuated in rat pups. In addition, we demonstrated that putative MCP regulates the motility of <I>C. sakazakii</I>, and the expression of the flagellar genes was enhanced in the absence of a functional <I>mcp</I> gene. Furthermore, a lack of the <I>mcp</I> gene also impaired the ability of <I>C. sakazakii</I> to form a biofilm. Our results demonstrate a regulatory role for MCP in diverse biological processes, including the virulence of <I>C. sakazakii</I> ATCC 29544. To the best of our knowledge, this study is the first to elucidate a potential function of a plasmid-encoded MCP homolog in the <I>C. sakazakii</I> sequence type 8 (ST8) lineage.</P>

판파를 이용한 화력 발전 설비의 물성 평가

조윤호(Younho Cho),정경식(Kyungsik Jung),이재선(Jaesun Lee) 대한기계학회 2010 大韓機械學會論文集A Vol.34 No.6

가스터빈 날개를 덮고 있는 덮개판(Lock plate)의 재료 물성을 유도초음파를 이용하여 측정을 하였다. Lock plate는 가스터빈 발전소에서 아무 극한 환경에서 작동을 하는 부분 중 하나이다. 초음파 속도와 감쇠계수가 서로 다른 3가지 조건의 열처리상태의 재료 물성을 측정하는데 사용되었다. 일반적인 기계적 파괴 인장 실험과 비교했을 때, 인코넬 x-750의 재료특성은 다른 열처리 조건에서 탄성계수와 포아슨비를 활용하여 비파괴적인 방법으로 더 효과적으로 알아냈다. 초음파 속도와 인코넬 x-750의 강도는 서로 비례관계에 있으며, 이러한 재료물성 측정은 여러 산업 분야에서 손상 측정에 활용될 수 있다. 또한 유도초음파 기법을 활용하여 장거리, 광범위한 진단으로 시간과 비용을 절감하는데 도움이 되리라 기대된다. Material properties of the lock plate, which covers the gas-turbine blade, are studied using ultrasonic guided waves. The lock plate is a crucial part of a gas-turbine power plant. The wave velocity and attenuation coefficient are measured to investigate the changes in the material properties under three heat-treatment conditions. Compared to the destructive mechanical tests, the material characterization of Inconel X-750 can be performed more efficiently and nondestructively by using ultrasonic guided waves; this characterization helps identify the changes occurring in its elastic moduli and Poisson's ratio under different heat-treatment conditions. The wave velocity and hardness of Inconel X-750 are proportional to each other. This nondestructive technique for the measurement of material properties can be widely used in various industries to avoid catastrophic failure. It is also expected that the guided-wave technique can be applied as a new cost- and time-saving inspection tool for longer and wider inspection ranges.