cAMP-Dependent Signalling is Involved in Adenosine-Stimulated Cl<SUP>⁣</SUP> Secretion in Rabbit Colon Mucosa

Sae Ock Oh,Eui Yong Kim,Jin Sup Jung,Jae Suk Woo,Yong Keun Kim,Sang Ho Lee 대한생리학회-대한약리학회 1998 The Korean Journal of Physiology & Pharmacology Vol.2 No.4

<P> An important property of the intestine is the ability to secrete fluid. The intestinal secretion is regulated by a number of substances including vasoactive intestinal peptide (VIP), ATP and different inflammatory mediators. One of the most important secretagogues is adenosine during inflammation. However, the controversy concerning the underlying mechanism of adenosine-stimulated Cl<SUP>⁣</SUP> secretion in intestinal epithelial cells still continues. To investigate the effect of adenosine on Cl<SUP>⁣</SUP> secretion and its underlying mechanism in the rabbit colon mucosa, we measured short circuit current (I<SUB>SC</SUB>) under automatic voltage clamp with DVC-1000 in a modified Ussing chamber. Adenosine, when added to the basolateral side of the muocsa, increased I<SUB>SC</SUB> in a dose-dependent manner. The adenosine-stimulated I<SUB>SC </SUB>response was abolished when Cl<SUP>⁣</SUP> in the bath solution was replaced completely with gluconate. In addition, the I<SUB>SC</SUB> response was inhibited by a basolateral Na-K-Cl cotransporter blocker, bumetanide, and by apical Cl<SUP>⁣</SUP> channel blockers, dephenylamine-2-carboxylate (DPC), 5-nitro-2-(3-phenyl-propylamino)-benzoate (NPPB), glibenclamide. Amiloride, an epithelial Na<SUP>⁢</SUP> channel blocker, and 4,4-diisothiocyanato-stilbene-2,2-disulphonate (DIDS), a Ca<SUP>2⁢</SUP>-activated Cl<SUP>⁣</SUP> channel blocker, had no effect. In the mucosa pre-stimulated with forskolin, adenosine did not show any additive effect, whereas carbachol resulted in a synergistic potentiation of the I<SUB>SC</SUB> response. The adenosine response was inhibited by 10 ㄍM H-89, an inhibitor of protein kinase A. These results suggest that the adenosine-stimulated I<SUB>SC</SUB> response is mediated by basolateral to apical Cl<SUP>⁣</SUP> secretion through a cAMP-dependent Cl<SUP>⁣</SUP> channel. The rank order of potencies of adenosine receptor agonists was 5 -(N-ethylcarboxamino)adenosine(NECA)>N<SUP>6</SUP>-(R-phenylisopropyl)adenosine(R- PIA)>2-[p-(2-carbonylethyl)-phenyl-ethylamino]-5 -N-ethylcarboxaminoadenosine(CGS21680). From the above results, it can be concluded that adenosine interacts with the A<SUB>2b</SUB> adenosine receptor in the rabbit colon mucosa and a cAMP-dependent signalling mechanism underlies the stimulation of Cl<SUP>⁣</SUP> secretion.

발생 중 척수 전구세포영역 확립에 있어 Gli3의 역할

오세옥(Sae Ock Oh),배수경(Soo Kyung Bae),윤 식(Sik Yoon),백선용(Sun Yong Baek),김봉선(Bong Seon Kim),김재봉(Jae Bong Kim) 대한해부학회 2005 Anatomy & Cell Biology Vol.38 No.1

Sonic hedgehog (Shh)는 발생 중 척수에서 형태발생인자(morphogen)로 작용한다. Shh의 농도에 따라 다른 종류의 전구세포영역(progenitor domain)과 그에 따른 신경세포가 생성된다. 그런데 Shh의 농도차이에 따라 어떻게 다른 종류의 신경세포가 생성되는지 아직 명확히 밝혀져 있지 않다. Shh의 농도차이가 어떻게 각 전구세포에서 해석되는지를 연구하기 위하여 Shh-/- 생쥐와 Shh-/-; Gli3-/- 생쥐에서 척수 전구세포영역 확립에 필수적인 homeoproteins의 발현을 제자리부합법으로 관찰하였다. Shh-/- 생쥐에서 class I homeoproteins (Pax6, Irx3, Dbx2, Dbx1)의 발현은 배쪽화하였고, class II homeoproteins (Nkx6.1, Nkx6.2, Olig2, Nkx2.2)의 발현은 사라졌다. Shh-/-; Gli3-/- 생쥐에서 class I homeoproteins의 발현은 부분적으로 회복되었으며, class II homeoproteins은 Nkx2.2를 제외하고 회복되었다. 이러한 결과는 Gli3가 class II homeoproteins의 발현을 조절할 수 있고, 이는 Shh의 농도경사가 신경관 전구세포에서 Gli 전사인자의 활성도 경사로 번역되어짐을 의미한다. University Sonic hedgehog (Shh) signaling has been shown to play instructive roles in developing spinal cord. Depending on the Shh concentration gradient, different progenitor domains and ventral neurons are induced. However, the way how the Shh gradient is translated into different progenitor domains, is not clear. To investigate the translation of the Shh gradient, we studied expressions of homeoproteins which are critical for establishment of progenitor domains, in the ventral neural tube of Shh-/- and Shh-/-;Gli3-/- mutants, using in situ hybridization. In Shh-/- mutant, the expressions of class II homeoproteins (Nkx6.1, Nkx6.2, Olig2, Nkx2.2) were totally repressed. The expressions of class I homeoproteins (Dbx1, Dbx2, Irx3, Pax6) were ventralized. In Shh-/-;Gli3-/-mutant, the expressions of class II homeoproteins except Nkx2.2 were restored. The expressions of class I homeoproteins were restored to its original position although their restoration is not complete. From above results, we conclude that Gli3 can regulate the expressions of class II homeoproteins, which suggests that the Shh gradient will be translated into Gli activity in the developing spinal cord.

등쪽신경관에서 Gli3의 역할

오세옥(Sae Ock Oh),배수경(Soo Kyung Bae),윤 식(Sik Yoon),백선용(Sun Yong Baek),김봉선(Bong Seon Kim),김재봉(Jae Bong Kim) 대한해부학회 2005 Anatomy & Cell Biology Vol.38 No.1

배쪽신경관 형성에 있어 Gli3의 필수적인 역할은 Shh-/- 생쥐나 Shh-/-;Gli3-/- 생쥐 등의 연구를 통해 잘 알려져 있다. 그러나 Gli3가 등쪽신경관에 많이 발현되고 있음에도 불구하고 그 역할이 아직 명확하지 않다. 본 연구에서는 등쪽신경관에서 Gli3의 역할을 구명하기 위하여 Gli3-/-생쥐의 등쪽신경관 발생을 관찰하였다. Phosphohistone 3에 대한 면역조직화학법과 BrdU 실험을 통하여 세포분열을 조사하였을 때 Gli3-/- 생쥐의 등쪽신경관에서 세포분열이 정상 생쥐에 비해서 증가하였다. 세포주기를 벗어난, 신경세포와 dI3 사이신경세포에서 각각 발현되는 HuC/D와 Isl1은 Gli3-/- 생쥐에서 정상 생쥐에 비해서 그 발현이 지연되었다. 전구세포에서 신경세포로의 분화를 유도하는 Ngn2의 발현도 Gli3-/- 생쥐에서 정상 생쥐에 비해서 지연되었다. HuC/D, Isl1 그리고 Ngn2의 발현 결과들은 Gli3-/- 생쥐의 등쪽신경관에서 신경분화가 지연되었음을 의미한다. 이상의 결과들는 Gli3가 등쪽신경관에서 신경전구세포의 세포분열과 분화에 관여함을 의미한다. Essential roles of Gli3 in ventral neural tube have been stressed from studies of Shh-/- and Shh-/-; Gli3-/- mutants. However, roles of Gli3 in dorsal neural tube have not been fully appreciated despite of its high expression. To find out roles of Gli3 in dorsal neural tube, we studied cell proliferation and neuronal differentiation in dorsal neural tube of Gli3-/- mutant. In Gli3-/- mutant, proliferation of progenitor cells in dorsal neural tube is increased compared to wild type embryos based on phosphohistone 3 immunohistochemistry and BrdU experiment. The appearances of HuC/D positive and Isl1 postive cells which represent postmitotic neurons and dI3 interneurons were delayed in Gli3-/- mutant compared to wild type embryo. The appearance of a proneural gene, Ngn2 was also delayed in Gli3-/- mutant compared to wild type embryo. Neuronal differentiation of progenitor cells in dorsal neural tube was delayed in Gli3-/- mutant compared to wild type embryos based on HuC/D, Isl1 and Ngn2 expressions. These results suggest that Gli3 plays important roles in cell proliferation and neuronal differentiation in dorsal neural tube. Thus our data shed a new light on the role of Gli3 in the development of neural tube.

Tg737oprk 생쥐에서 배쪽신경관의 형태발생

오세옥(Sae Ock Oh),배수경(Soo Kyung Bae),윤 식(Sik Yoon),백선용(Sun Yong Baek),김봉선(Bong Seon Kim),김재봉(Jae Bong Kim) 대한해부학회 2005 Anatomy & Cell Biology Vol.38 No.1

Polaris는 Tg737 유전자에 의해 발현되는 단백질인데, 섬모를 구성하며 그 기능에 중요한 역할을 한다. 최근 섬모 형성에 관련된 분자들의 기능이 저하된 생쥐에서 배쪽신경관의 발생장애가 나타나며 이러한 발생장애가 Shh 신호전달체계와 관련이 있음이 제시되었다. 본 연구에서는 섬모 형성 장애가 있는 Tg737oprk 생쥐에서 신경관 발생장애를 면역조직화학법으로 분석하여 Polaris와 Shh 신호전달체계와의 관련성을 규명하고자 하였다. Tg737oprk 생쥐에서는 V3 사이신경 전구세포와 마루판은 발생하지 않았으나 V2 사이신경세포와 운동신경 세포는 보존되었다. 보존된 V2 사이신경세포와 운동신경세포는 그 생성영역이 배쪽화되었으며, 서로 섞여 있었다. Nkx6.1과 Olig2 전사인자 발현은 Tg737oprk 생쥐에서 보존되었으며 Olig2의 발현 영역이 배쪽화되었다. 이러한 발생장애는 Shh 신호전달체계에 장애가 있는 Shh-/-; Gli3-/-생쥐나 Gli2-/-; Gli3-/- 생쥐에서와 아주 유사하다. 따라서 이러한 결과는 Polaris의 기능이 정상적인 Shh 신호전달을 위해 필요하다는 것을 나타낸다. Polaris, which is encoded by Tg737 gene, has been associated with cilia formation. Recently phenotypes of ventral neural tube in mice who have abnormal cilia formation have been reported to be similar with those of sonic hedgehog (Shh) signaling mutants. These interesting findings lead us to further examine the patterning of ventral neural tube in Tg737oprk mice. In this study, we found that motor neuron and V2 interneuron were preserved whereas P3 progenitor domain and floor plate were missing in Tg737oprk mutant. V2 and motor neurons in Tg737oprk were ventralized and mixed with each other. Nkx6.1 and Olig2 expressions were preserved and the Olig2 expression was ventralized in Tg737oprk. These penotypes are quite similar with those in Shh-/-; Gli3-/- or Gli2-/-; Gli3-/- mutants, suggesting that the function of Polaris might be involved in Shh signaling.

Gastric stem cells and gastric cancer stem cells

Myoung-Eun Han,Sae-Ock Oh 대한해부학회 2013 Anatomy & Cell Biology Vol.46 No.1

The gastric epithelium is continuously regenerated by gastric stem cells, which give rise to various kinds of daughter cells, including parietal cells, chief cells, surface mucous cells, mucous neck cells, and enteroendocrine cells. The self-renewal and differentiation of gastric stem cells need delicate regulation to maintain the normal physiology of the stomach. Recently, it was hypothesized that cancer stem cells drive the cancer growth and metastasis. In contrast to conventional clonal evolution hypothesis, only cancer stem cells can initiate tumor formation, self-renew, and differentiate into various kinds of daughter cells. Because gastric cancer can originate from gastric stem cells and their self-renewal mechanism can be used by gastric cancer stem cells, we review here how critical signaling pathways, including hedgehog, Wnt, Notch, epidermal growth factor, and bone morphogenetic protein signaling, may regulate the self-renewal and differentiation of gastric stem cells and gastric cancer stem cells. In addition, the precancerous change of the gastric epithelium and the status of isolating gastric cancer stem cells from patients are reviewed.

PC-12 세포에서 Cisplatin에 의한 Apoptosis의 기전

이영우,오세옥,조원호,이상호 대한신경외과학회 1998 Journal of Korean neurosurgical society Vol.27 No.11

Involvement of Phospholipase D in Norepinephrine Uptake in PC12 Cells

Jong-Joo Rhee,Sae-Ock Oh,Young-Rae Kim,Jong-Il Park,Seung-Kiel Park 대한의생명과학회 2009 Biomedical Science Letters Vol.15 No.4

Phospholipase D (PLD) is an enzyme hydrolyzing phosphatidylcholine to phosphatidic acid (PA) and choline. We investigated the involvement of PLD1 in the uptake of norepinephrine (NE) in PC12 cells, pheochromocytoma cells. NE uptake was specific in PC12 cells because nomifensine, a specific blocker of NE transporter, blocked NE uptake. Inhibition of PLD function in PC12 cells by the treatment of butanol suppressed the NE uptake. In contrast, overexpression of PLD1 in PC12 cells increased NE uptake efficiently. These results suggest that PLD activity is involved in NE uptake. We explored the action mechanism of PLD in NE uptake. PA phosphatase inhibitor, propranolol, blocks the formation of PKC activator diacylglycerol from PA. Propranolol treatment to PC12 cells blocked dramatically the uptake of NE. Specific PKC inhibitors, GF109203X and Ro31-8220, blocked NE uptake. Taken together, we suggest for the first time that PLD1 activity is involved in NE uptake via the activation of PKC.

Activation of SAPK and Increase in Bak Levels during Ceramide and Indomethacin-Induced Apoptosis in HT29 Cells

Ju Ho Kim,Sae Ock Oh,Sung Sook Jun,Jin Sup Jung,Jae Suk Woo,Yong Keun Kim,Sang Ho Lee 대한생리학회-대한약리학회 1999 The Korean Journal of Physiology & Pharmacology Vol.3 No.1

<P> It has been reported that activation of sphingomyelin pathway and nonsteroidal anti-inflammatory drugs (NSAIDS) inhibit the promotion of colon carcinoma. Ceramide, a metabolite of sphingomyelin, and indomethacin were shown to induce apoptosis in colon carcinoma cells. However, the mechanisms of ceramide- and indomethacin-induced apoptosis in the colon carcinoma cells are not clearly elucidated. Recent studys showed that indomethacin-induced apoptosis in colon cancer cells through the cyclooxygenase-independent pathways, and that may be mediated by generation of ceramide. In this study, we compared effects of ceramide and indomethacin on important modulators of apoptotic processes in HT29 cells, a human colon cancer cell line. Ceramide and indomethacin induced apoptosis dose- and time- dependently. Ceramide and indomethacin increased stress-activated protein kinase (SAPK) activity, and decreased mitogen-activated protein kinase (MAPK) activity. The expression of Bak was increased by the treatment of ceramide and indomethacin. The expression of other Bcl-2 related proteins (Mcl-1, Bcl-X<SUB>L</SUB>, Bax) which were known to be expressed in colon epithelial cells was not changed during the ceramide- and indomethacin-induced apoptosis. Our results suggest that ceramide and indomethacin share common mechanisms for induction of apoptosis in HT29 cells.

Effect of Endothelin-1 on Proliferation and Differentiation of Rat Tracheal Epithelial Cells

Chang Soo Kim,Sae Ock Oh,Jae Suk Woo,Jin Sup Jung,Yong Keun Kim,Sang Ho Lee 대한생리학회-대한약리학회 1998 The Korean Journal of Physiology & Pharmacology Vol.2 No.6

<P> A number of substances involved in the proliferation and differentiation of the tracheobronchial epithelium have been identified. The defects in the control of the proliferation and differentiation of tracheobronchial epithelial cells appear to constitute crucial steps in the transition of normal cells to neoplastic ones. Endothelin-1 is produced by tracheal epithelial cells, and its receptors are present in tracheal epithelial cells. However, the effect of endothelin-1 on the proliferation and differentiation of tracheal epithelial cells has not been clearly elucidated. This study was undertaken to investigate these actions of endothelin-1 in primary cultured cells of rat tracheal epithelia. Endothelin-1 stimulated proliferation of tracheal epithelial cells 1.5-fold when compared with that of control cells. Endothelin-1 increased mitogen-activated protein kinase (MAPK) activity. Herbimycin A, a tyrosine kinase inhibitor, inhibited endothelin-1-induced proliferation of epithelial cells. The treatment of endothelin-1 during the primary culture of tracheal epithelial cells increased AB-PAS-stained cell population and ciliated cell population 6.5 fold and 1.5 fold, respectively, when compared with those in control cells. The responsiveness to carbachol and forskolin in the Cl<SUP>-</SUP> secretion was increased 1.7 and 1.9 fold, respectively, in the endothelin-treated epithelial cells. These results indicated that endothelin-1 increases proliferation via MAPK pathway and stimulates differentiation to secretory and ciliated cells in rat tracheal epithelial cells.

The molecular mechanism for nuclear transport and its application

Yun Hak Kim,Myoung-Eun Han,Sae-Ock Oh 대한해부학회 2017 Anatomy & Cell Biology Vol.50 No.2

Transportation between the cytoplasm and the nucleoplasm is critical for many physiological and pathophysiological processes including gene expression, signal transduction, and oncogenesis. So, the molecular mechanism for the transportation needs to be studied not only to understand cell physiological processes but also to develop new diagnostic and therapeutic targets. Recent progress in the research of the nuclear transportation (import and export) via nuclear pore complex and four important factors affecting nuclear transport (nucleoporins, Ran, karyopherins, and nuclear localization signals/nuclear export signals) will be discussed. Moreover, the clinical significance of nuclear transport and its application will be reviewed. This review will provide some critical insight for the molecular design of therapeutics which need to be targeted inside the nucleus.