• Molecules and Cells
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• v.26 no.6
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• pp.576-582
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• 2008

Nervous system development takes place after positional information has been established along the dorsal-ventral (D/V) axis. The initial subdivision provided by a gradient of nuclear dorsal protein is maintained by the zygotic genes expressed along the D/V axis. In this study, an investigation was conducted to determine the range of Dpp function in repressing the expression of eagle (eg) that is present in intermediate neuroblasts defective (ind) and muscle specific homeobox (msh) gene domain. eg is expressed in neuroblast (NB) 2-4, 3-3 and 6-4 of the msh domain, and NB7-3 of the ind domain at the embryonic stage 11. In decapentaplegic (dpp) loss-of-function mutant embryos, eg was ectopically expressed in the dorsal region, while in dpp gain-of-function mutants produced by sog or sca-GAL4/UAS-dpp, eg was repressed by Dpp. It is worthy of note that Dpp produced from sim;;dpp embryos showed that Dpp could function at long range. However, Dpp produced from en-GAL4/UAS-dpp or wg-GAL4/UAS-dpp primarily acted at short-range. This result demonstrated that this discrepancy seems to be due to the repression of Dpp to EGFR signaling in sim;;dpp embryos. Taken together, these results suggest that Dpp signaling works at short-range, but can function indirectly at long-range by way of repression of EGFR signaling during embryonic neurogenesis.

• The Transactions of the Korean Institute of Power Electronics
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• v.27 no.1
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• pp.1-8
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• 2022

Recently, photovoltaic (PV) systems have been gradually applied in eco-friendly vehicle applications to improve fuel economy. The relevant market is expected to continue to grow because the installation of large-capacity PV systems to other eco-friendly vehicles, such as electric buses and trains, is being considered. However, in a PV system, power imbalance between submodules and low power generation efficiency occur due to factors such as cell aging, contamination, and shading. To resolve this problem, various differential power processing (DPP) converters have been researched and developed. However, conventional DPP converters suffer from large volume and low efficiency. Therefore, to apply DPP converters to eco-friendly vehicles, increasing efficiency and reducing volume and price compared with existing DPP converters is necessary. In this paper, a novel DPP converter with an integrated transformer is proposed and analyzed. The proposed DPP converter uses a single magnetic component by integrating transformers and secondary sides of conventional DPP converters. Therefore, the proposed DPP converter shows high power density and high efficiency, and it is suitable for PV systems in eco-friendly vehicle applications.

• Proceedings of the Korean Society of Applied Pharmacology
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• 2008.04a
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• pp.5-20
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• 2008

GLP-1-based drugs (GLP-1 analogues and DPP IV inhibitors) and incretin mimetics are currently one of the most exciting classes of agents for type II diabetes. GLP-1, a gut peptide, is an incretin that potentiates glucose-dependent insulin release from the pancreas, slows GI-transit and stimulates the proliferation of beta-cells. DPP IV inhibitors act like incretins by inhibiting DPP IV which inactivates GLP-1. LC15-0133 is a competitive, reversible DPP IV inhibitor ($IC_{50}$ = 24 nM, Ki=0.247 nM) with excellent selectivity over other critical human proteases such as DPP II, DPP 8, elastase, trypsin. and urokinase. LC15-0133 showed long half-life and good bioavailability in rats and dogs. Inhibition of plasma DPP IV activity by LC15-0133 was kept more than 50% 24 hours after oral dosing in rats and dogs at 0.1 mg/kg and 0.02 mg/kg, respectively. The Minimum effective doses of LC15-0133 were 0.01 mg/kg for lowering blood glucose excursion during oral glucose tolerance test and 0.1 mg/kg for increasing glucose-induced GLP-1 response in C57BL/6 mice. Repeat oral administration of LC15-0133 for 1 month delayed the progression to diabetes and reduced HbA1c levels in a dose-dependent manner in Zucker Diabetic Fatty rats. In conclusion, LC15-0133 is a novel, potent, selective and orally active DPP IV inhibitor and showed an excellent blood glucose lowering effects in various animal models.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.9
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• pp.306-314
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• 2019

As dipeptidyl peptidase-4(DPP-4) inhibitors are used widely as a secondary treatment for type 2 diabetes because they tend to be well tolerated with minimal side effects, the human DPP-4(hDPP-4) gene was injected into a pig zygote through micro-injection, and 1-cell stage fertilized embryos were then transplanted surgically into the oviduct. Three pigs were fertilized with hDPP-4 genes and produced sixteen piglets, in which one male piglet was identified to be transgenic. Finally, transgenic pigs showing hDPP-4 gene expression in the tail were produced. Western blot and RT-PCR analysis confirmed that the hDPP-4 is expressed strongly in the membrane cells of the transgenic pig, and that the hDPP-4 gene appears in various tissues and tails. This suggests that the expression vector is normally expressed in transgenic pigs. These results are anticipated to be a model animal to check the endocrine function for insulin resistance that occurs in a hDPP-4 transgenic pig and to increase its value for use as a material in newly developed medicines.

• Biomolecules & Therapeutics
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• v.29 no.2
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• pp.154-165
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• 2021

This study aimed to investigate whether the antidiabetic drugs dipeptidyl peptidase 4 (DPP4) inhibitors such as evogliptin and sitagliptin affect the membrane DPP4 (mDPP4) enzymatic activity and immune function of T helper1 (Th1) cells in terms of cytokine expression and cell profiles. The mDPP4 enzymatic activity, cytokine expression, and cell profiles, including cell counts, cell viability, DNA synthesis, and apoptosis, were measured in pokeweed mitogen (PWM)-activated CD4+CD26+ H9 Th1 cells with or without the DPP4 inhibitors, evogliptin and sitagliptin. PWM treatment alone strongly stimulated the expression of mDPP4 and cytokines such as interleukin (IL)-2, IL-10, tumor necrosis factor-alpha, interferon-gamma, IL-13, and granulocyte-macrophage colony stimulating factor in the CD4+CD26+ H9 Th1 cells. Evogliptin or sitagliptin treatment potently inhibited mDPP4 activity in a dose-dependent manner but did not affect either the cytokine profile or cell viability in PWM-activated CD4+CD26+ H9 Th1 cells. These results suggest that, following immune stimulation, Th1 cell signaling pathways for cytokine expression function normally after treatment with evogliptin or sitagliptin, which efficiently inhibit mDPP4 enzymatic activity in Th1 cells.

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.48-49
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• 2017

태양광 발전 시스템 구현에 있어 가장 큰 문제점 중 하나는 불균일한 태양빛 조건에서의 전체 시스템 발전량 감소이다. 이를 해결하기 위해 module-integrated converter (MIC), dc optimizer, differential power processing (DPP) 등 다양한 컨버터가 연구되고 있다. 그 중에서도 DPP 컨버터는 낮은 전력변환 손실로 높은 시스템 효율을 얻을 수 있어 최근 많은 주목을 받고 있다. 보통 그리드 연결형 태양광발전 시스템에 적용되는 직렬 DPP의 경우, 이미 많은 연구가 진행되고 있지만, 병렬 DPP의 경우 아직 많은 연구가 필요한 상황이다. 본 논문에서는 front-end 컨버터의 존재 유무에 따른 두 가지 병렬 DPP 컨버터 배열을 비교 분석 하였다. Front-end 컨버터가 적용된 병렬 DPP 컨버터 배열의 경우, dc 전압과 태양전지의 전압 차이를 최소화해 전력 변환 손실을 감소시킬 수 있지만, front-end 컨버터에서 추가적인 전력 변환 손실이 발생한다. Front-end 컨버터가 없는 경우, dc 전압과 태양전지의 전압차이가 커 DPP 컨버터에서 발생하는 전력 변환 손실이 커진다. 따라서 주어진 조건 아래 효율적인 병렬 DPP 컨버터 디자인을 위한 가이드라인을 본 논문에서 제시하고자 한다.

• Journal of Microbiology and Biotechnology
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• v.30 no.3
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• pp.427-438
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• 2020

Middle East respiratory syndrome coronavirus (MERS-CoV) infects the lower respiratory airway of humans, leading to severe acute respiratory failure. Unlike human dipeptidyl peptidase 4 (hDPP4), a receptor for MERS-CoV, mouse DPP4 (mDPP4) failed to support MERS-CoV infection. Consequently, diverse transgenic mouse models expressing hDPP4 have been developed using diverse methods, although some models show no mortality and/or only transient and mild-to-moderate clinical signs following MERS-CoV infection. Additionally, overexpressed hDPP4 is associated with neurological complications and breeding difficulties in some transgenic mice, resulting in impeding further studies. Here, we generated stable hDPP4-transgenic mice that were sufficiently susceptible to MERS-CoV infection. The transgenic mice showed weight loss, decreased pulmonary function, and increased mortality with minimal perturbation of overexpressed hDPP4 after MERS-CoV infection. In addition, we observed histopathological signs indicative of progressive pulmonary fibrosis, including thickened alveolar septa, infiltration of inflammatory monocytes, and macrophage polarization as well as elevated expression of profibrotic molecules and acute inflammatory response in the lung of MERS-CoV-infected hDPP4-transgenic mice. Collectively, we suggest that this hDPP4-transgenic mouse is useful in understanding the pathogenesis of MERS-CoV infection and for antiviral research and vaccine development against the virus.

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.205-206
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• 2016

본 논문에서는 전압 밸런싱을 위한 부스트-포워드 컨버터를 이용한 피드백 방식 차동전력조절(DPP, Differential Power Processing) 시스템을 제안한다. 이 시스템은 서로 직렬 연결된 태양광패널을 입력으로 연결된 상태에서 DPP 컨버터가 각 태양광패널에 병렬로 연결된다. 또한 DPP 컨버터의 출력도 직렬로 연결되고 전체는 부스트 컨버터에 의해 통합되어 최종적으로 인버터를 통해 계통 및 기타 시스템에 연결된다. 이러한 구조의 DPP 시스템은 태양광패널 중의 한 부분에 그늘짐 현상이 발생할 경우 DPP 컨버터의 출력에 영향을 미치게 되어 전압불균형이 발생한다. 이는 전체 시스템의 효율과 인버터와 같은 계통과 연결 시 정상작동 여부에 큰 영향을 미칠 수 있기 때문에 DPP 컨버터 출력부의 전압 밸런싱을 수행하는 회로가 필요하다. 제안하는 회로는 이러한 DPP 시스템에서 적용할 수 있는 부스트-포워드 컨버터를 이용한 전압 밸런싱 회로이다. 이를 검증하기 위하여 컴퓨터 시뮬레이션을 이용하였다.

• Journal of Sericultural and Entomological Science
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• v.54 no.1_2
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• pp.1-5
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• 2016

The dpp gene originated from the silkworms is an important gene that is well conserved in the genome of humans, cattle, rodents, poultry and Drosophila. The dpp gene belonging to the TGF-beta (Transforming Growth Factor-beta) superfamily is known to play an important role in several developmental stages. The $TGF-{\beta}$ gene family is a genetically well-conserved and playing an important role gene family in various species such as determining cell proliferation and differentiation, apoptosis and cell fate. In this review, we have confirmed the following studies data. The recent studies on the silkworm dpp gene have confirmed for the first time the biological functions such as promoting osteogenesis activity. In addition, previous data shows that dpp have developmental functions such as morphogenetic materials at the blastophyllum stage, induction of the mesoblast at the late embryonic stage and involved in the proliferation and morphogenesis of imaginal disc in adult development. We found the splice variant of the dpp gene originated from the wildtype silkworm by using comparative genomics. It has provided important data for basic research based on genetics studies of these processes may promote a better understanding of evolution. Silkworm is a medicinal insect and is approved for its safety. It is used as a natural antibiotic for promoting growth as a medical material, a health functional food, and a feed additive. Therefore, it is necessary to present various data to obtain more value of functional insect.

• BMB Reports
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• v.51 no.12
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• pp.636-641
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• 2018

DPP4 (dipeptidyl peptidase-4), a highly conserved transmembrane glycoprotein with an exo-peptidase activity, has been shown to contribute to glucose metabolism, immune regulation, signal transduction, and cell differentiation. Here, we show that DPP4 is involved in control of activin/nodal signaling in Xenopus early development. In support of this, gain of function of DPP4 augmented Smad2 phosphorylation as well as expression of target genes induced by activin or nodal signal. In addition, Dpp4 and Xnr1 showed synergistic effect on induction of ectopic dorsal body axis, when co-injected at suboptimal doses in early embryos. Conversely, saxagliptin, a DPP4 inhibitor repressed activin induction of Smad2 phosphorylation. Notably, overexpression of Dpp4 disrupted specification of dorsal body axis of embryo, leading to malformed phenotypes such as spina bifida and a shortened and dorsally bent axis. Together, these results suggest that DPP4 functions as a potentiator of activin/nodal signaling pathway.