• Molecules and Cells
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• 제45권11호
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• pp.855-867
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• 2022

For proper function of proteins, their subcellular localization needs to be monitored and regulated in response to the changes in cellular demands. In this regard, dysregulation in the nucleocytoplasmic transport (NCT) of proteins is closely associated with the pathogenesis of various neurodegenerative diseases. However, it remains unclear whether there exists an intrinsic regulatory pathway(s) that controls NCT of proteins either in a commonly shared manner or in a target-selectively different manner. To dissect between these possibilities, in the current study, we investigated the molecular mechanism regulating NCT of truncated ataxin-3 (ATXN3) proteins of which genetic mutation leads to a type of polyglutamine (polyQ) diseases, in comparison with that of TDP-43. In Drosophila dendritic arborization (da) neurons, we observed dynamic changes in the subcellular localization of truncated ATXN3 proteins between the nucleus and the cytosol during development. Moreover, ectopic neuronal toxicity was induced by truncated ATXN3 proteins upon their nuclear accumulation. Consistent with a previous study showing intracellular calcium-dependent NCT of TDP-43, NCT of ATXN3 was also regulated by intracellular calcium level and involves Importin α3 (Imp α3). Interestingly, NCT of ATXN3, but not TDP-43, was primarily mediated by CBP. We further showed that acetyltransferase activity of CBP is important for NCT of ATXN3, which may acetylate Imp α3 to regulate NCT of ATXN3. These findings demonstrate that CBP-dependent acetylation of Imp α3 is crucial for intracellular calcium-dependent NCT of ATXN3 proteins, different from that of TDP-43, in Drosophila neurons.

• Molecules and Cells
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• 제46권4호
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• pp.209-218
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• 2023

In induced pluripotent stem cells (iPSCs), pluripotency is induced artificially by introducing the transcription factors Oct4, Sox2, Klf4, and c-Myc. When a transgene is introduced using a viral vector, the transgene may be integrated into the host genome and cause a mutation and cancer. No integration occurs when an episomal vector is used, but this method has a limitation in that remnants of the virus or vector remain in the cell, which limits the use of such iPSCs in therapeutic applications. Chemical reprogramming, which relies on treatment with small-molecule compounds to induce pluripotency, can overcome this problem. In this method, reprogramming is induced according to the gene expression pattern of extra-embryonic endoderm (XEN) cells, which are used as an intermediate stage in pluripotency induction. Therefore, iPSCs can be induced only from established XEN cells. We induced XEN cells using small molecules that modulate a signaling pathway and affect epigenetic modifications, and devised a culture method which can produce homogeneous XEN cells. At least 4 passages were required to establish morphologically homogeneous chemically induced XEN (CiXEN) cells, whose properties were similar to those of XEN cells, as revealed through cellular and molecular characterization. Chemically iPSCs derived from CiXEN cells showed characteristics similar to those of mouse embryonic stem cells. Our results show that the homogeneity of CiXEN cells is critical for the efficient induction of pluripotency by chemicals.

• Journal of Microbiology and Biotechnology
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• 제33권10호
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• pp.1281-1291
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• 2023

Infectious diseases caused by drug-resistant Escherichia coli (E. coli) pose a critical concern for medical institutions as they can lead to high morbidity and mortality rates. In this study, amygdalin exhibited anti-inflammatory and antioxidant activities, as well as other potentials. However, whether it could influence the drug-resistant E. coli-infected cells remained unanswered. Amygdalin was therefore tested in a cellular model in which human macrophages were exposed to resistant E. coli. Apoptosis was measured by flow cytometry and the lactate dehydrogenase (LDH) assay. Western immunoblotting and quantitative reverse-transcription polymerase chain reaction (qRT-PCR) were used to quantify interleukin-18 (IL-18), interleukin-1β (IL-1β), and interleukin-6 (IL-6). The production of reactive oxygen species (ROS) in macrophages was detected by ROS kit. The expression of pan-apoptotic proteins in macrophages was measured by qRT-PCR and Western immunoblotting. Drug-Resistant E. coli inhibited cell viability and enhanced apoptosis in the cellular model. In cells treated with amygdalin, this compound can inhibit cell apoptosis and reduce the expression of pro - inflammatory cytokines such as IL-1β, IL-18 and IL-6. Additionally, it decreases the production of PANoptosis proteins, Furthermore, amygdalin lowered the levels of reactive oxygen species induced by drug-resistant E. coli, in cells, demonstrating its antioxidant effects. Amygdalin, a drug with a protective role, alleviated cell damage caused by drug-resistant E. coli in human macrophages by inhibiting the PANoptosis signaling pathway.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2023년도 임시총회 및 춘계학술대회
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• pp.54-54
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• 2023

Nypa fruticans Wurmb (N. fruticans) is a plant that belongs to Araceae and N. fruticans is mainly found in tropical mangrove systems. The parts (leaves, stems, and roots) of N. fruticans are traditionally used for asthma, sore throat, and liver disease. N. fruticans contains flavonoids and polyphenols, which are substances that have inhibitory effects on cancer and oxidant. In previous studies, some pharmaceutical effects of N. fruticans on melanogenesis and inflammation have been reported. The present study is conducted to investigate the effect of the ethyl acetate fraction of N. fruticans (ENF) on oxidative DNA damage and UVB-induced DNA damage. DNA damage response (DDR) pathway is important in research on cancer, apoptosis, and so on. DDR pathways are considered a crucial factor affecting the alleviation of cellular damage. ENF could reduce oxidative DNA damage derived from reactive oxygen species by the Fenton reaction. Also, ENF reduced the intensity of intracellular ROS in the live cell image by DCFDA assay. UVB is known to cause skin and cellular damage, then finally contribute to causing the formation of tumors. As for the strategies of reducing DNA damage by UVB, inhibition of p53, H2AX, and Chk2 can be important indexes to protect the human body from DNA damage. As a result of confirming the protective effect of ENF for UVB damage, MMPs significantly decreased, and the expression of apoptosis-related factors tended to decrease. In conclusion, ENF can provide protective effects against double-stranded DNA break (DSB) caused by oxidative DNA damage and UVB-induced DNA damage. These results are considered to be closely related to the protective effect against radicals based on catechin, epicatechin, and isoquercitrin contained in ENF. Based on these results, it is thought that additional mechanism studies for inhibiting cell damage are needed.

• Molecules and Cells
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• 제41권4호
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• pp.282-289
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• 2018

Interleukin-17A (IL-17A) is a pro-inflammatory cytokine mainly derived from T helper 17 cells and is known to be involved in the pathogenesis of chronic obstructive pulmonary disease (COPD). Cigarette smoke (CS) has been considered as a primary risk factor of COPD. However, the interaction between CS and IL-17A and the underlying molecular mechanisms have not been clarified. In the current study, we investigated the effects of cigarette smoke extract (CSE) on IL-17A-induced IL-8 production in human bronchial epithelial cells, and sought to identify the underlying molecular mechanisms. IL-8 production was significantly enhanced following treatment with both IL-17A and CSE, while treatment with either IL-17A or CSE alone caused only a slight increase in IL-8 production. CSE increased the transcription of IL-17RA/RC and surface membrane expression of IL-17R, which was suppressed by an inhibitor of the phosphoinositide 3-kinase (PI3K)/Akt pathway (LY294002). CSE caused inactivation of glycogen synthase $kinase-3{\beta}$ ($GSK-3{\beta}$) via the PI3K/Akt pathway. Blockade of $GSK-3{\beta}$ inactivation by overexpression of constitutively active $GSK-3{\beta}$ (S9A) completely suppressed the CSE-induced up-regulation of IL-17R expression and the CSE-induced enhancement of IL-8 secretion. In conclusion, inactivation of $GSK-3{\beta}$ via the PI3K/Akt pathway mediates CSE-induced up-regulation of IL-17R, which contributes to the enhancement of IL-17A-induced IL-8 production.

• The Korean Journal of Physiology and Pharmacology
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• 제14권1호
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• pp.37-43
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• 2010

The serine/threonine kinase Akt has been shown to play a role of multiple cellular signaling pathways and act as a transducer of many functions initiated by growth factor receptors that activate phosphatidylinositol 3-kinase (PI3K). It has been reported that phosphorylated Akt activates eNDS resulting in the production of NO and that NO stimulates soluble guanylate cyclase (sGC), which results in accumulation of cGMP and subsequent activation of the protein kinase G (PKG). It has been also reported that PKG activates PI3K/Akt signaling. Therefore, it is possible that PI3K, Akt, eNOS, sGC, and PKG form a loop to exert enhanced and sustained activation of Akt. However, the existence of this loop in eNOS-expressing cells, such as endothelial cells or astrocytes, has not been reported. Thus, we examined a possibility that Akt phosphorylation might be enhanced via eNOS/sGC/PKG/PI3K pathway in astrocytes in vivo and in vitro. Phosphorylation of Akt was detected in astrocytes after KA treatment and was maintained up to 72 h in mouse hippocampus. 2 weeks after KA treatment, astrocytic Akt phosphorylation was normalized to control. The inhibition of eNOS, sGC, and PKG significantly decreased Akt and eNDS phosphorylation induced by KA in astrocytes. In contrast, the decreased phosphorylation of Akt and eNDS by eNDS inhibition was significantly reversed with PKG activation. The above findings in mouse hippocampus were also observed in primary astrocytes. These data suggest that Akt/eNOS/sGC/PKG/PI3K pathway may constitute a loop, resulting in enhanced and sustained Akt activation in astrocytes.

• Journal of Microbiology and Biotechnology
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• 제27권1호
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• pp.197-205
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• 2017

Exposure of Jurkat T cell clone (J/Neo cells) to acacetin (5,7-dihydroxy-4'-methoxyflavone), which is present in barnyard millet (Echinochloa esculenta (A. Braun)) grains, caused cytotoxicity, enhancement of apoptotic $sub-G_1$ rate, Bak activation, loss of mitochondrial membrane potential (${\Delta}{\Psi}m$), activation of caspase-9 and caspase-3, degradation of poly(ADP-ribose) polymerase, and FITC-Annexin V-stainable phosphatidylserine exposure on the external surface of the cytoplasmic membrane without accompanying necrosis. These apoptotic responses were abrogated in Jurkat T cell clone (J/Bcl-xL) overexpressing Bcl-xL. Under the same conditions, cellular autophagic responses, including suppression of the Akt-mTOR pathway and p62/SQSTM1 down-regulation, were commonly detected in J/Neo and J/Bcl-xL cells; however, formation of acridine orange-stainable acidic vascular organelles, LC3-I/II conversion, and Beclin-1 phosphorylation (Ser-15) were detected only in J/Neo cells. Correspondingly, concomitant treatment with the autophagy inhibitor (3-methyladenine or LY294002) appeared to enhance acacetin-induced apoptotic responses, such as Bak activation, ${\Delta}{\Psi}m$ loss, activation of caspase-9 and caspase-3, and apoptotic $sub-G_1$ accumulation. This indicated that acacetin could induce apoptosis and cytoprotective autophagy in Jurkat T cells simultaneously. Together, these results demonstrate that acacetin induces not only apoptotic cell death via activation of Bak, loss of ${\Delta}{\Psi}m$, and activation of the mitochondrial caspase cascade, but also cytoprotective autophagy resulting from suppression of the Akt-mTOR pathway. Furthermore, pharmacologic inhibition of the autophagy pathway augments the activation of Bak and resultant mitochondrial damage-mediated apoptosis in Jurkat T cells.

• Applied Biological Chemistry
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• 제36권3호
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• pp.184-190
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• 1993

Rhodobacter sphaeroides 균주가 생산하는 ${\delta}-aminolevulinic\;acid(ALA)$의 생산성에 관하여 in vivo, in vitro 상에서 기질 및 관련 화합물을 이용하여 검토하였다. $C_5\;ALA$ 생합성계에 의한 ALA yield 대비의 $C_4$ 생합성계에 의한 비율은 in vive 상에서 0.78인 반면, in vitro 상에서의 비율은 1.37이었다.$C_4\;C_5$ 각 계의 기질 첨가 배양에 의한 cell-free system의 $C_4,\;C_5$ 계의 발현도는 미첨가 배양에 의한 system과 비교하여 각각 1.35, 1.52로 증가하였으나, 증가한 계에 대한 상대계의 발현도가 억제되어, $C_4$ 와 $C_5$ 계가 각각 0.91, 0.83으로 나타났다. ${\gamma}-Glutamyl\;derivatives$의 세포내 uptake rates는 L-glutamic acid를 기준으로 비교해서 D-glutamic acid, 0.55: D-glutamine, 0.5: L-glutamine, 0.4: ${\gamma}-L-glutamyl\;ethylester$, 0.3: GSH 및 Glu-pNA, 0의 순서를 보였다. Uptake rate와 관계없이 in vivo 상에서 L-과 D-glutamine이 L-, D-glutamic acid보다 균체 외 ALA의 생산에 있어서 각각 높은 yield의 효과를 보였다.

• Asian Pacific Journal of Cancer Prevention
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• 제13권12호
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• pp.6155-6157
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• 2012

Background: Mutations in the MAPK (Mitogen Activated Protein Kinase) signaling pathway - EGFR/Ras/RAF/MEK have been associated with the development of several carcinomas. ERK2, a downstream target of the MAPK pathway and a founding member of the MAPK family is activated by cellular signals emanating at the cell membrane. Activated ERK2 translocates into the nucleus to transactivate genes that promote cell proliferation. MKP - a dual specific phosphatase - interacts with activated ERK2 via the common docking (CD) domain of the later to inactivate (dephosphorylate) and effectively terminate further cell proliferation. A constitutively active form of ERK2 carrying a single point mutation - E322K in its CD domain, was earlier reported by our laboratory. In the present study, we investigated the prevalence of this CD domain E322K mutation in 88 well differentiated OSCC tissue samples. Materials and Method: Genomic DNA specimens isolated from 88 oral squamous cell carcinoma tissue samples were amplified with primers flanking the CD domain of the ERK2 gene. Subsequently, PCR amplicons were gel purified and subjected to direct sequencing to screen for mutations. Results: Direct sequencing of eighty eight OSCC samples identified an E322K CD domain mutation in only one (1.1%) OSCC sample. Conclusions: Our result indicates that mutation in the CD domain of ERK2 is rare in OSCC patients, which suggests the role of genetic alterations in other mitogenic genes in the development of carcinoma in the rest of the patients. Nevertheless, the finding is clinically significant, as the relatively rare prevalence of the E322K mutation in OSCC suggests that ERK2, being a common end point signal in the multi-hierarchical mitogen activated signaling pathway may be explored as a viable drug target in the treatment of OSCC.

• 한국발생생물학회지:발생과생식
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• 제10권2호
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• pp.85-92
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• 2006

본 논문은 포유동물 난소에서의 신속한 프로게스테론(P4) 선호 전달경로에 관해 현재 통용되는 지식을 요약하였다. P4는 안드로겐과 에스트로겐 합성 과정에서의 중요한 중간 산물이면서 그 자체로도 배란, 난포폐쇄(atresia), 황체형성과정(luteinization)에서 결정적인 역할을 하며, 모든 포유동물의 초기 임신 유지에 필수적이다. 이와 같은 생리적인 중요성에도 불구하고 포유동물 난소에서의 정확한 P4 작용기작은 아직까지도 완전히 알려져 있지 않다. 이러한 관점에서 볼 때, 비유전자 수준이면서 전사와 무관한 P4의 세포내 작용을 매개하는 수용체의 실체에 관해 오래 동안 계속된 의문과 논란은 과학적인 흥미를 유발하는 생식생리학의 주요 관심사이다. 포유류 난소에서 P4는 1) 잘 알려진 유전자 수준의 경로(genomic pathway)인 호르몬이 소위 고전적인 세포 내의 수용체에 결합하고, 이어 리간드-호르몬 복합체가 전사조절물질로 작용하여 표적 유전자 발현을 조절하거나, 2) 유전자에 직접 작용하지 않기 때문에 비유전자 수준이라 불리우는 경로(non-genomic pathway)로 작용한다. P4의 비유전자 수준 작용의 주요한 특징은 (i) 신속하고, (ii) 전사억제제에 반응하지 않고, (iii) 세포막과 연관된 물질들에 의해 신호가 전달된다. 아마도 난소에서 P4의 비유전자 수준 작용은 (a) 세포막 또는 그 근처에 위치한 고전적인 P4 수용체(PGR), (b) 세포막 프로게스틴 수용체(membrane progestin receptors; MPR $\alpha$, MPR $\beta$ and MPR $\gamma$) 패밀리, (c) progesterone receptor membrane component I(PGRMC1), 그리고 (d) serpine I mRNA binding protein(SERBP1)의 세포막 복합체에 의해 매개되는 것으로 추정된다. 포유류 난소에서의 P4 작용에 대한 완전한 이해를 위해서는 향후 많은 연구가 필요할 것이다.