• The Korean Journal of Physiology and Pharmacology
• /
• 제15권6호
• /
• pp.383-388
• /
• 2011

Regulators of G-protein signaling (RGS) proteins are regulators of $Ca^{2+}$ signaling that accelerate the GTPase activity of the G-protein ${\alpha}$ -subunit. RGS1, RGS2, RGS4, and RGS16 are expressed in the pancreas, and RGS2 regulates G-protein coupled receptor (GPCR)-induced $Ca^{2+}$ oscillations. However, the role of RGS4 in $Ca^{2+}$ signaling in pancreatic acinar cells is unknown. In this study, we investigated the mechanism of GPCR-induced $Ca^{2+}$ signaling in pancreatic acinar cells derived from $RGS4^{-/-}$ mice. $RGS4^{-/-}$ acinar cells showed an enhanced stimulus intensity response to a muscarinic receptor agonist in pancreatic acinar cells. Moreover, deletion of RGS4 increased the frequency of $Ca^{2+}$ oscillations. $RGS4^{-/-}$ cells also showed increased expression of sarco/endoplasmic reticulum $Ca^{2+}$ ATPase type 2. However, there were no significant alterations, such as $Ca^{2+}$ signaling in treated high dose of agonist and its related amylase secretion activity, in acinar cells from $RGS4^{-/-}$ mice. These results indicate that RGS4 protein regulates $Ca^{2+}$ signaling in mouse pancreatic acinar cells.

• International Journal of Oral Biology
• /
• 제37권1호
• /
• pp.37-41
• /
• 2012

Pancreatic acinar cells exhibit a polarity that is characterized by the localization of secretory granules at the apical membrane. However, the factors that regulate cellular polarity in these cells are not well understood. In this study, we investigated the effect of Mist1, a basic helix-loop-helix transcription factor, on the cellular architecture of pancreatic acinar cells. Mist1-null mice displayed secretory granules that were diffuse throughout the pancreatic acinar cells, from the apical to basolateral membranes, whereas Mist1 heterozygote mice showed apical localization of secretory granules. Deletion of the Mist1 gene decreased the expression of type 3 inositol 1,4,5-triphosphate receptors ($IP_3R$) but did not affect apical localization and expression of $IP_3R2$. Mist1-null mice also displayed an increase in luminal areas and an increase in the expression of zymogen granules in pancreatic acinar cells. These results suggest that Mist1 plays a critical role in polar localization of cellular organelles and in maintaining cellular architecture in mouse pancreatic acinar cells.

• Applied Microscopy
• /
• 제18권2호
• /
• pp.34-46
• /
• 1988

췌장비 acinar cell에서 자극-분비 반응 과정을 알아보기 위하여 전자현미경을 이용하였다. 분비 촉진 물질인 아세틸콜린이나 MNNG의 투여에 따른 세포내 반응이 세포의 형태적 변화로서 잘 나타났으며 특히 guanylate cyclase를 활성화시키는 것으로 알려진 MNNG는 투여 후 일정시간 뒤 세포내에 많은 분비물 과립의 형성을 유발하였다. 이러한 결과에서 볼때 췌장의 acinar cell을 아세틸콜린으로 자극할 경우 guanylate cyclase는 지속적 반응 단계의 초기에 분비에 가세하는 것으로 생각되었고 cycloheximide나 dibucaine은 지속적 반응을 억제하는 것으로 나타났다. 또 췌장의 acinar cell에서는 분비물 과립의 형성이 소포체에서 직접 이루어지는 것으로 생각되었다.

• The Korean Journal of Physiology and Pharmacology
• /
• 제13권6호
• /
• pp.409-416
• /
• 2009

Acute pancreatitis is a multifactorial disease associated with the premature activation of digestive enzymes. The genes expressed in pancreatic acinar cells determine the severity of the disease. The present study determined the differentially expressed genes in pancreatic acinar cells treated with cerulein as an in vitro model of acute pancreatitis. Pancreatic acinar AR42J cells were stimulated with $10^{-8}$ M cerulein for 4 h, and genes with altered expression were identified using a cDNA microarray for 4,000 rat genes and validated by real-time PCR. These genes showed a 2.5-fold or higher increase with cerulein: lithostatin, guanylate cyclase, myosin light chain kinase 2, cathepsin C, progestin-induced protein, and pancreatic trypsin 2. Stathin 1 and ribosomal protein S13 showed a 2.5-fold or higher decreases in expression. Real-time PCR analysis showed time-dependent alterations of these genes. Using commercially available antibodies specific for guanylate cyclase, myosin light chain kinase 2, and cathepsin C, a time-dependent increase in these proteins were observed by Western blotting. Thus, disturbances in proliferation, differentiation, cytoskeleton arrangement, enzyme activity, and secretion may be underlying mechanisms of acute pancreatitis.

• 대한약리학회:학술대회논문집
• /
• 대한약리학회 2006년도 58th Annual Meeting of The Korean Society of Pharmacology
• /
• pp.63-63
• /
• 2006

• International Journal of Oral Biology
• /
• 제46권3호
• /
• pp.134-139
• /
• 2021

Under physiological conditions, calcium (Ca²⁺) regulates essential functions of polarized secretory cells by the stimulation of specific Ca²⁺ signaling mechanisms, such as increases in intracellular Ca²⁺ concentration ([Ca²⁺]_i) via the store-operated Ca²⁺ entry (SOCE) and the receptor-operated Ca²⁺ entry (ROCE). Homer proteins are scaffold proteins that interact with G protein-coupled receptors, inositol 1,4,5-triphosphate (IP₃) receptors, Orai1-stromal interaction molecule 1, and transient receptor potential canonical (TRPC) channels. However, their role in the Ca²⁺ signaling in exocrine cells remains unknown. In this study, we investigated the role of Homer2 in the Ca²⁺ signaling and regulatory channels to mediate SOCE and ROCE in pancreatic acinar cells. Deletion of Homer2 (Homer2^-/-) markedly increased the expression of TRPC3, TRPC6, and Orai1 in pancreatic acinar cells, whereas these expressions showed no difference in whole brains of wild-type and Homer2^-/- mice. Furthermore, the response of Ca²⁺ entry by carbachol also showed significant changes to the patterns regulated by specific blockers of SOCE and ROCE in pancreatic acinar cells of Homer2^-/- mice. Thus, these results suggest that Homer2 plays a critical role in the regulatory action of the [Ca²⁺]_i via SOCE and ROCE in mouse pancreatic acinar cells.

• Archives of Pharmacal Research
• /
• 제21권6호
• /
• pp.657-663
• /
• 1998

The enzyme responsible for the synthesis of nitric oxide (NO) from L-arginine in mammalian tissues is known as nitric oxide synthase (NOS) (EC.1.14.13.39). In the present study, the role of NO in the regulation of exocrine secretion was investigated in rat pancreatic acinar cells. Treatment of rat pancreatic acinar cells with cholecystokinin-octapeptide (CCK-OP) resulted in an increase in the arginine conversion to citrulline, the amount of $NO_X$, the release of amylase, and the level of CGMP. Especially, CCK-OP-stimulated increase of arginine to citrulline transformation, the amount of $NO_X$, and CGMP level were completely counteracted by the inhibitor of NOS, NG-monomethyl-L-arginine (MMA), by contrast, that of amylase release was partially reduced. Furthermore, MMA-induced decrease of NOS activity and amylase release showed dose-dependent pattern. The data on the time course of CCK-OP-induced citrulline formation and CGMP rise indicate that NOS and guanylate cyclase were activated by treatment of CCK-OP. However, the mechanism of agonist-stimulated guanylate cyclase activation in acinar cells remains unknown. Therefore, activation of NOS is one of the early events in receptor-mediated cascade of reactions in pancreatic acinar cells and NO, not completely, but partially mediate pancreatic enzyme exocrine secretion.

• The Korean Journal of Physiology and Pharmacology
• /
• 제3권5호
• /
• pp.521-528
• /
• 1999

Reactive oxygen species (ROS), generated by infiltrating neutrophils, are considered as an important regulator in the pathogenesis and deveolpment of pancreatitis. The present study aims to investigate whether neutrophils primed by $4{\beta}-phorbol\;12{\beta}-myristate\;13{\alpha}-acetate$ (PMA) affect the productions $H_2O_2$ and lipid peroxide (LPO), $NF-_{\kappa}B$ activation and cytokine production in pancreatic acinar cells, and whether these alterations were inhibited by an antioxidant, N-acetylcysteine (NAC) and superoxide dismutase (SOD). $H_2O_2$ (ferrithiocyanate method), LPO (as thiobarbiturate reactive substances), and cytokines $(IL-l{\bata},\; IL-6,\;TNF-{\alpha};\;enzyme-linked\;immunosorbent\;assay)$ and $NF-_{\kappa}B$ activation (electrophoretic mobility shift assay) were analyzed in acinar cells treated with or without PMA-primed neutrophils in the absence or presence of NAC (10 mM) or SOD (300 U/ml). As a result, the productions of H2O2, LPO and $TNF-{\alpha}$ were increased with the ratio of PMA-primed neutrophils to acinar cells while the productions of LPO, $IL-l{\beta},\;IL-6\;and\;TNF-{\alpha}$ were increased with time. PMA-primed neutrophils resulted in the activation of $NF-_{\kappa}B.$ Both NAC and SOD inhibited neutrophil-induced alterations in acinar cells. In conclusion, ROS, generated by neutrophils, activates $NF-_{\kappa}B,$ resulting in upregulation of inflammatary cytokines in acinar cells. Antioxidants might be clinically useful antiinflammatory agents by inhibiting oxidant-mediated activation of $NF-_{\kappa}B$ and decreasing cytokine production.

• 생명과학회지
• /
• 제23권11호
• /
• pp.1404-1408
• /
• 2013

본 연구에서는 마우스 췌장의 선포세포(primary acinar cell)에서 에탄올에 의해 유도된 염증성 손상에 미치는 녹차의 생리활성 물질인 EGCG의 효과를 췌장분비 효소의 활성과 선포세포에서의 기능 회복 관련 마크로 알려진 유전자들(AMPK, RKIP 및 Reg1)의 발현 조절 측면에서 조사하였다. 대조군에 비해 에탄올이 처리된 세포에서는 ${\alpha}$-amylase와 chymotrypsin의 활성이 증가되었지만, EGCG 처리에 의하여 그들 활성이 유의적으로 감소하였다. 세포 생존 및 보호와 관련 있는 AMPK 인산화 수준은 에탄올 단독 처리시 그 발현이 감소하였지만, EGCG 처리에 의하여 유의적으로 회복되었다. 세포 사멸과 세포독성 조절과 연관이 있는 RKIP 또한 그 발현 경향이 AMPK인산화 변화의 정도와 유사하였다. 또한 베타세포 재생에 관여하는 Reg1 발현은 에탄올이 처리된 선포세포에 EGCG를 처리하였을 경우 그 발현량이 유의적으로 증가하였다. 이상의 결과들을 종합하여, 항산화성 폴리페놀인 EGCG는 알코올성 췌장염으로 인한 세포의 손상이나 당뇨병 예방과 회복에 치료적 효과를 가질 수 있다고 제안한다.

• 한국생물물리학회:학술대회논문집
• /
• 한국생물물리학회 2003년도 정기총회 및 학술발표회
• /
• pp.56-56
• /
• 2003

Isolated single pancreatic acinar cells have long been used as a good model for studying many kinds of signaling processes due to their good structural and functional polarities without a significant validation. In this study, we have examined morphological and functional changes of the dissociated single pancreatic acinar cells by imaging cytosolic Ca$\^$2+/ concentration, exocytosis of granules, and by observing their shapes with confocal microscopy.