• Proceedings of the KSAR Conference
• /
• 2003.06a
• /
• pp.32-32
• /
• 2003

소 난자의 체외성숙 과정에서 세포질 내 단백질의 생산과 축적의 변화는 핵 및 세포질 성숙과 밀접한 관계가 있다는 보고가 있지만, 난자의 성숙과 관련된 특정 단백질의 종류에 대한 보고는 없었다. 따라서 본 연구는 한우 난자의 체외성숙과 관련된 단백질의 생산 및 축적의 변화와 그 종류에 대해서 검토하였다. 체외성숙 시간(4.5, 9, 13.5, 18 및 24시간)에 따른 배양액 내의 단백질 합성의 변화는 2D gel electrophoresis를 이용하였고, 단백질 spot에 대해서는 peptide mass fingerprinting(PMF) 방법을 이용하였다. 또한 단백질 측정 시간에 신선 체외성숙 배양액으로 교환 후 난포란의 핵성숙과 배발달율을 검토하였다. 그 결과 한우 난포란의 체외성숙 시간에 따라 배양액에서 단백질의 양 및 질적인 변화를 확인하였다. 그리고 총 296개 단백질 spot들을 확인하였고, 그 중 30개 spot에서 유의적인 변화가 인정되었다. 또한 유의적인 변화를 보인 spot에 대한 PMF 분석을 통하여 Apolipoprotein A-1 precursor, Alpha enolase, Aldose reductase, 43kDa collectin precursor, Heat shock 27kDa protein, Plasminogen activator inhibitor-1 precursor, Thrombospondin 1 및 Transitional endoplasmic reticulum ATPase가 동정되었다 그리고 총 단백질 합성 경향은 0∼4.5 시간에는 감소하였고, 13.5∼18시간에 증가 한 후 다시 감소하는 경향을 나타내었으며, 단백질의 종류도 시간대별로 현저한 변화가 있었다. 한편 단백질을 측정하는 시기에 신선 체외성숙 배양액으로 교환한 후 난포란의 핵성숙 및 배발달율을 검토한 결과 18시간 체외성숙군에서 9시간째의 교환이 유의적으로 높은 핵성숙을 나타내었으나, 배발달율에서는 유의성이 인정되지 않았다. 그러나 24시간 체외성숙군에서 18시간째의 배양액 교환은 8세포기 및 배반포 발달율이 유의적(P<0.05)으로 높았다. 연구 결과로부터 소 난자의 체외성숙 시간에 따른 단백질 합성 경향의 차이를 확인하였고, 유의적인 변화를 나타낸 8가지의 단백질을 분리할 수 있었으며, 향후 이들 작용기전에 대한 연구가 필요하다고 사료된다.

• Korean Journal of Plant Resources
• /
• v.28 no.6
• /
• pp.682-689
• /
• 2015

Abeliophyllum distichum Nakai (A. distichum) has been reported to exert the inhibitory effect on angiotensin converting enzyme and aldose reductase. Recently, our group found that branch extracts of A. distichum (EAFAD-B) induce apoptosis through ATF3 activation in human colon cancer cells. However, anti-cancer reagents exert their activity through the regulation of various molecular targets. Therefore, the elucidation of potential mechanisms of EAFAD-B for anti-cancer activity may be necessary. To elucidate the potential mechanism of EAFAD-B for anti-cancer activity, we evaluated the regulation of cyclin D1 in human colon cancer cells. EAFAD-B decreased cellular accumulation of cyclin D1 protein. However, cyclin D1 mRNA was not changed by EAFAD-B. Inhibition of proteasomal degradation by MG132 attenuated EAFAD-B-mediated cyclin D1 downregulation and the half-life of cyclin D1 was decreased in the cells treated with EAFAD-B. In addition, EAFAD-B induced cyclin D1 phosphorylation at threonine-286 and the point mutation of threonine-286 to alanine attenuated EAFAD-B-mediated cyclin D1 proteasomal degradation. Inhibitions of both ERK1/2 by PD98059 and NF-κB by a selective inhibitor, BAY 11-7082 suppressed cyclin D1 downregulation by EAFAD-B. From these results, we suggest that EAFAD-B-mediated cyclin D1 downregulation may result from proteasomal degradation through its threonine-286 phosphorylation via ERK1/2-dependent NF-κB activation. The current study provides new mechanistic link between EAFAD-B and anti-cancer activity in human colon cancer cells.

• YAKHAK HOEJI
• /
• v.41 no.6
• /
• pp.782-788
• /
• 1997

This study was designed to characterize glucose-enhancing effects on endotoxin-induced prostaglandin production in primary cultured rat vascular smooth muscle cells (VSMC). High glucose treatment significantly augmented prostaglandin (PG) synthesis in lipopolysaccharide (LPS)-stimulated VSMC and this effect was maximal at the concentration of 4mg/ml. It has been reported that increases in glucose metabolism through sorbitol pathway could alter the cytosolic $NADH/NAD^+$ ratio and this change favors de novo synthesis of diacylglycerol (DAG) and, in turn. Results in the activation of protein kinase C (PKC) in vascular tissues. Protein kinase C (PKC) inhibitors, staurosporin and H7, blocked the glucose enhancing effect, and DAG, a PKC activator, significantly increased the PG production stimuated by LPS. Sodium pyruvate, which can reverse the alteration in cytosolic NADH/NAD+ ratio, reduced the high glucose effect on PG production. And also, zopolrestat, a strong aldose reductase inhibitor, almost completely blocked the augmentation effect of glucose on PG synthesis. Arachidonic acid release was significantly increased in high glucose treated group, which implied the increase in $PLA_2$ activity was associated with glucose enhancing effect. Metabloic, labeling study clearly showed that de novo synthesis of prostaglandin H synthase-2 (PGHS-2) is greatly increased in high glucose treated group and this was mitigated by the treatment of zopolrestat. Taken together, the activation of PKC through sorbitol pathway increased the activities of $PLA_2$ and PGHS which resulted in the augmentation in LPS-induced PG production in high glucose treated VSMC.

• Journal of Microbiology and Biotechnology
• /
• v.31 no.6
• /
• pp.867-874
• /
• 2021

Epalrestat (EPS) is a brain penetrant aldose reductase inhibitor, an approved drug currently used for the treatment of diabetic neuropathy. At near-plasma concentration, EPS induces glutathione biosynthesis, which in turn reduces oxidative stress in the neuronal cells. In this study, we found that EPS reduces neurodegeneration by inhibiting reactive oxygen species (ROS)-induced oxidative injury, mitochondrial membrane damage, apoptosis and tauopathy. EPS treatment up to 50 µM did not show any toxic effect on SH-SY5Y cell line (neuroblastoma cells). However, we observed toxic effect at a concentration of 100 µM and above. At 50 µM concentration, EPS showed better antioxidant activity against H₂O₂ (100 µM)-induced cytotoxicity, ROS formation and mitochondrial membrane damage in retinoic acid-differentiated SH-SY5Y cell line. Furthermore, our study revealed that 50 µM of EPS concentration reduced the glycogen synthase kinase-3 β (GSK3-β) expression and total tau protein level in H₂O₂ (100 µM)-treated cells. Findings from this study confirms the therapeutic efficacy of EPS on regulating Alzheimer's disease (AD) by regulating GSK3-β and total tau proteins phosphorylation, which helped to restore the cellular viability. This process could also reduce toxic fibrillary tangle formation and disease progression of AD. Therefore, it is our view that an optimal concentration of EPS therapy could decrease AD pathology by reducing tau phosphorylation through regulating the expression level of GSK3-β.

• The Korean Journal of Physiology and Pharmacology
• /
• v.3 no.4
• /
• pp.447-454
• /
• 1999

The production of nitric oxide (NO) and the expression of inducible nitric oxide synthase (iNOS) are known to be modulated by a variety of factors. Recent study showed that endotoxin-induced NO synthesis and iNOS expression were greatly enhanced by elevation of extracellular glucose concentration in murine macrophages. Although this was suggested to be due to the activation of protein kinase C (PKC) via sorbitol pathway, there was lack of evidence for this speculation. This study was performed to delineate the underlying intracellular mechanisms of glucose-enhancing effect on endotoxin-induced NO production in Raw264.7 macrophages. The levels of NO release induced by lipopolysaccharide (LPS) significantly increased by the treatment of glucose in a concentration dependent manner and also, this effect was observed in LPS-preprimed cells. Concurrent incubation of cells with PKC inhibitors, H-7 or chelerythrine, and LPS resulted in the diminution of NO production regardless of glucose concentration but this was not in the case of LPS-prepriming, that is, chelerythrine showed a minimal effect on the glucose- enhancing effect. PMA, a PKC activator, did not show any significant effect on glucose-associated NO production. Modulation of sorbitol pathway with zopolrestat, an aldose reductase inhibitor, did not affect LPS-induced NO production and iNOS expression under high glucose condition. And also, sodium pyruvate, which is expected to normalize cytosolic $NADH/NAD^+$ ratio, did not show any significant effect at concentrations of up to 10 mM. Glucosamine marginally increased the endotoxin-induced nitrite release in both control and high glucose treated group. 6-diazo-5-oxonorleucine (L-DON) and azaserine, glutamine: fructose- 6-phosphate amidotransferase (GFAT) inhibitors, significantly diminished the augmentation effect of high glucose on endotoxin-induced NO production. On the other hand, negative modulation of GFAT inhibitors was not reversed by the treatment of glucosamine, suggesting the minimal involvement, if any, of glucosamine pathway in glucose-enhancing effect. In summary, these results strongly suggest that the hexosamine biosynthesis pathway and the activation of PKC via sorbitol pathway do not contribute to the augmenting effect of high glucose on endotoxin induced NO production in macrophage-like Raw264.7 cells.