• 한국미생물·생명공학회지
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• 제50권2호
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• pp.293-300
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• 2022

Lipoteichoic acid (LTA) regulates the immune system, including inflammatory responses, through TLR2-mediated signaling pathways. LTA isolated from Staphylococcus aureus (aLTA) has been shown to induce apoptosis, but the detailed mechanism has not been identified. We found that aLTA induced apoptosis through an autocrine mechanism in the human monocyte-like cell line, THP-1. We observed that the expression level of the anti-apoptosis protein, Bcl2, was suppressed in LTA-treated THP-1 cells. In addition, the cytokines, TNF-α and IFN-γ, which have been shown to induce apoptosis in some cell lines, were involved in THP-1 cell death via the modulation of Bcl2. The suppression of Bcl2 by aLTA was recovered when the negative regulator, SOCS-1, was knocked down. Taken together, these results showed that aLTA induced apoptosis in THP-1 cells through an autocrine mechanism of cytokines and SOCS-1-mediated Bcl2 inhibition.

• BMB Reports
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• 제48권2호
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• pp.109-114
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• 2015

The COX-2/$PGE_2$ pathway has been implicated in the occurrence and progression of cancer. The underlying mechanisms facilitating the production of COX-2 and its mediator, $PGE_2$, in cancer survival remain unknown. Herein, we investigated $PGE_2$-induced COX-2 expression and signaling in HL-60 cells following menadione treatment. Treatment with $PGE_2$ activated anti-apoptotic proteins such as Bcl-2 and Bcl-xL while reducing pro-apoptotic proteins, thereby enhancing cell survival. $PGE_2$ not only induced COX-2 expression, but also prevented casapse-3, PARP, and lamin B cleavage. Silencing and inhibition of COX-2 with siRNA transfection or treatment with indomethacin led to a pronounced reduction of the extracellular levels of $PGE_2$, and restored the menadione- induced cell death. In addition, pretreatment of cells with the MEK inhibitor PD98059 and the PKA inhibitor H89 abrogated the $PGE_2$-induced expression of COX-2, suggesting involvement of the MAPK and PKA pathways. These results demonstrate that $PGE_2$ signaling acts in an autocrine manner, and specific inhibition of $PGE_2$ will provide a novel approach for the treatment of leukemia.

• Molecules and Cells
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• 제45권4호
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• pp.257-272
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• 2022

In addition to inducing apoptosis, caspase inhibition contributes to necroptosis and/or autophagy depending on the cell type and cellular context. In macrophages, necroptosis can be induced by co-treatment with Toll-like receptor (TLR) ligands (lipopolysaccharide [LPS] for TLR4 and polyinosinic-polycytidylic acid [poly I:C] for TLR3) and a cell-permeable pan-caspase inhibitor zVAD. Here, we elucidated the signaling pathways and molecular mechanisms of cell death. We showed that LPS/zVAD- and poly I:C/zVAD-induced cell death in bone marrow-derived macrophages (BMDMs) was inhibited by receptor-interacting protein kinase 1 (RIP1) inhibitor necrostatin-1 and autophagy inhibitor 3-methyladenine. Electron microscopic images displayed autophagosome/autolysosomes, and immunoblotting data revealed increased LC3II expression. Although zVAD did not affect LPS- or poly I:C-induced activation of IKK, JNK, and p38, it enhanced IRF3 and STAT1 activation as well as type I interferon (IFN) expression. In addition, zVAD inhibited ERK and Akt phosphorylation induced by LPS and poly I:C. Of note, zVAD-induced enhancement of the IRF3/IFN/STAT1 axis was abolished by necrostatin-1, while zVAD-induced inhibition of ERK and Akt was not. Our data further support the involvement of autocrine IFNs action in reactive oxygen species (ROS)-dependent necroptosis, LPS/zVAD-elicited ROS production was inhibited by necrostatin-1, neutralizing antibody of IFN receptor (IFNR) and JAK inhibitor AZD1480. Accordingly, both cell death and ROS production induced by TLR ligands plus zVAD were abrogated in STAT1 knockout macrophages. We conclude that enhanced TRIF-RIP1-dependent autocrine action of IFNβ, rather than inhibition of ERK or Akt, is involved in TLRs/zVAD-induced autophagic and necroptotic cell death via the JAK/STAT1/ROS pathway.

• Archives of Pharmacal Research
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• 제17권2호
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• pp.93-99
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• 1994

Macrtophages play an important role in defense against virus infection by intrinsic resistance and by extrinsic resistance. Since interferon-induced enzymes which are 2'-5' oligoadenylate synthetase and p1/eIF-2 protein kinase have been shown to be involved in the inhibition of viral replication, I examined the mechanism by which poly I:C, an interferon inducer, exerts its antiviral effects in inflammatory macrophages infected with herpes simplex virus type 1 (HSV-1). The data presented here demonstrate that poly I:C-induced antiviral activity is partially due to the activation of 2'-5' pligoadenylate synthetase. The activation of 2'-5' oligoadenlate A synthetase by poly I:C is also at least mediated via the production of interferon-.betha.. Taken together, these data indicate that interferon-.betha. produced in response to poly I:C acts in an autocrine manner to activate the 2'-5' oligoadenylate synthetase and to induce resistance to HSV-1.

• 한국의학물리학회지:의학물리
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• 제25권3호
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• pp.157-166
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• 2014

뉴론에서 ATP는 분비 과립내에 신경전달물질과 함께 다량 저장되어 있다가 신경전달물질과 함께 분비되는 것으로 알려져 있으므로 신경전달물질의 자극-분비(stimulus-secretion) coupling 과정에 있어 중요한 조절작용을 할 것으로 기대된다. 그러므로 본 연구에서는 뉴론과 그 발생학적 기원이 동일한 부신수질 세포(adrenal chromaffin cell)를 대상으로 하여 세포막 칼슘통로를 통한 세포막 전류에 미치는 ATP의 영향을 측정함으로써 신경전달물질이 자극-분비 coupling 과정에 작용하는 ATP의 조절 작용을 알아보고자 하였다. 부신수질 세포의 칼슘통로를 통한 세포막 전류는 패치클램프 테크닉으로 기록하였다. 10 mM $Ba^{2+}$을 포함한 세포 외 용액에서, $Ba^{2+}$ current는 0.1 mM ATP를 세포외부에 처치했을 때, 평균 $36{\pm}6%$ (n=6) 감소되어 나타났고 ATP를 씻어준 후 전류는 다시 회복되는 가역적 반응을 보였다. ATP의 전류 억제 기전을 알아보고자 칼슘통로에서 관찰되는 현상 중의 하나인 소통(facilitation)현상을 기록하였다. +80 mV의 큰 prepulse를 준 후 바로 테스트 펄스를 주며 측정한 전류는 큰 prepulse에 의해 억제효과가 풀리는(disinhibition) 현상을 나타내었다. ATP 처치 후 큰 자극을 주어 $37{\pm}5%$ (n=11)의 $Ba^{2+}$ 전류 증가가 있었고 이는 ATP가 없는 상태에서 순수하게 큰 자극에 의해 소통되는 $25{\pm}3%$ (n=12)과 유의한 차이를 보였다(p<0.05). ATP의 억제 기전이 G-protein을 매개로 한 것인지를 알아보고자 가수분해 되지 않는 GTP 유도체인 $GTP{\gamma}S$를 세포 내에 준 후 $Ba^{2+}$ 전류를 기록하였다. $GTP{\gamma}S$에 의해 55%의 전류 크기의 감소가 있었고 이 환경에서 큰 prepulse를 인가하였을 때 $34{\pm}4%$ (n=19)의 소통현상을 보였다. 이는 $GTP{\gamma}S$가 없는 환경에서의 $25{\pm}3%$ (n=12)의 소통현상을 보인 것과 유의한 차이를 보였다(p<0.05). $Ba^{2+}$ current trace의 활성화 과정(activation)을 curve-fitting한 결과, control은 single exponential curve로 fitting된 반면, ATP 또는 $GTP{\gamma}S$를 처치한 경우, 그리고 ATP와 $GTP{\gamma}S$ 모두 처치한 경우에서는 double-exponential curve로 가장 잘 fitting이 되었다. 즉, ATP나 $GTP{\gamma}S$를 처치했을 때 모두 전류가 더 느리게 활성화되는 모양을 나타내었고, 이상의 결과로 미루어 ATP와 $GTP{\gamma}S$는 같은 방식으로 칼슘통로를 억제하고, 이러한 억제효과는 세포막에 아주 큰 전압을 걸어주면 칼슘 통로에 결합했던 G-protein이 막전압 의존적으로 떨어짐으로써 소실(disinhibition)된다고 해석된다. 본 연구에서 확인한 ATP의 칼슘통로 억제효과는 자체 크로마핀 세포 또는 주변 세포에서 아드레날린이 적게 분비되게 하는 autocrine 또는 paracrine inhibition 과정의 중요한 기전으로 작용할 것이다.

• Journal of mucopolysaccharidosis and rare diseases
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• 제2권2호
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• pp.43-45
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• 2016

Whole body energy balance is achieved through the coordinated regulation of energy intake and energy expenditure in various tissues including liver, muscle and adipose tissues. A positive energy imbalance by excessive energy intake or insufficient energy expenditure results in obesity and related metabolic diseases. Although there have been many obesity treatment trials aimed at the reduction of energy intake, these strategies have achieved only limited success because of their associated adverse effects. Serotonin is among those traditional pharmacological targets for anti-obesity treatment because central 5-HT functions as an anorexigenic neurotransmitter in the brain. Thus, there have been many trials aimed at increasing the activity of 5-HT in the central nervous system, and some of the developed methods are already used in the clinical setting as anti-obesity drugs. However, recent studies suggest the new functions of peripheral serotonin in energy homeostasis ranging from the endocrine regulation by gut-derived serotonin to the autocrine/paracrine regulation by adipocyte-derived serotonin. Pharmacological inhibition of 5-HT synthesis leads to inhibition of lipogenesis in epididymal white adipose tissue (WAT), induction of browning in inguinal WAT and activation of adaptive thermogenesis in brown adipose tissue (BAT). Fat specific Tph1 knock-out (Tph1 FKO) mice exhibit similar phenotypes as mice with pharmacological inhibition of 5-HT synthesis, suggesting the localized effects of 5-HT in adipose tissues. In addition, Htr3a KO mice exhibit increased energy expenditure in BAT and Htr2a KO mice exhibit the decreased lipid accumulation in WAT. These data suggest the clinical significance of the peripheral serotonergic system as a new therapeutic target for anti-obesity treatment.

• Molecules and Cells
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• 제24권3호
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• pp.431-436
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• 2007

Stem cell-based therapy is being considered as an alternative treatment for cardiomyopathy. Hence understanding the basic molecular mechanisms of cardiomyocyte differentiation is important. Besides BMP or Wnt family proteins, $TGF-{\beta}$ family members are thought to play a role in cardiac development and differentiation. Although $TGF-{\beta}$ has been reported to induce cardiac differentiation in embryonic stem cells, the differential role of $TGF-{\beta}$ isoforms has not been elucidated. In this study, employing the DMSO-induced cardiomyocyte differentiation system using P19CL6 mouse embryonic teratocarcinoma stem cells, we investigated the $TGF-{\beta}$-induced signaling pathway in cardiomyocyte differentiation. $TGF-{\beta}1$, but not the other two isoforms of $TGF-{\beta}$, was induced at the mRNA and protein level at an early stage of differentiation, and Smad2 phosphorylation increased in parallel with $TGF-{\beta}1$ induction. Inhibition of $TGF-{\beta}1$ activity with $TGF-{\beta}1$-specific neutralizing antibody reduced cell cycle arrest as well as expression of the CDK inhibitor $p21^{WAF1}$. The antibody also inhibited induction of the cardiac transcription factor Nkx2.5. Taken together, these results suggest that $TGF-{\beta}1$ is involved in cardiomyocyte differentiation by regulating cell cycle progression and cardiac gene expression in an autocrine or paracrine manner.

• Journal of Life Science
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• 제11권1호
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• pp.22-26
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• 2001

In estrogen-dependent MCF-7 human breast cancer cells, $E_2$ at 10 nM stimulated cell proliferation to over 200% compared to the untreated control. EGF and TGF${\alpha}$, which are known as the autocrine/paracrine growth factors induced by $E_2$, also directly stimulated the cell growth in almost as the same extent as $E_2$. DFMO which is the specific inhibitor of ODC could inhibit cell growth even at as low as 0.5 mM. In the treatment with 1 mM DFMO for 4 days, the cell growth was inhibited to 38% of the control. HO-TAM at 1 ${\mu}$M could inhibit the proliferation of MCF-7 cells to 19% of the control. Those inhibitory effects were also found in the cells stimulated with $E_2$, EGF, and TGF${\alpha}$. The inhibitory effects were found even in 2 days of treatment. However, $E_2$, EGF, and TGF${\alpha}$ did not give any effect in the protein synthesis. Neither DFMO or HO-TAM gave any effect on the total protein synthesis. But the pattern of protein secretion was noticeably influenced by the growth stimulants or inhibitors. Proteins of 160, 52, 42, 36, and 32 kDa belonged to the major secretory proteins. Especially, 42 and 36 kDa proteins were most significantly influenced by the treatment of $E_2$, EGF, or TGF$\alpha$. DFMO and HO-TAM inhibited the secretion of these major proteins.

• The Journal of Korean Physical Therapy
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• 제14권4호
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• pp.87-94
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• 2002

Low intensity laser irradiation is potential physical agent that triggers the muscle regeneration by previous study. In muscle regeneration, a number of growth factors also promotes that is triggered in response to muscle damage. The transforming growth factor(TGF)-$\beta$ is involved in the activation of cell proliferation and the inhibition of cell differentiation in muscle regeneration. This is secreted not only autocrine system but also paracrine and endocrine. Therefore, We investigated that effects of Gallium aluminum arsenide(GaAlAs) diode laser for the expression of TGF-$\beta$ on lumbar spinal cord after extensor digitorum muscle crush injury. After laser irradiation, the immunoreactivity of TGF-$\beta$ was increased bilaterally in gray mater of spinal cord. Especially, in 1 day, experimental group was highed than control, and in 3 day, lateral motor nucleus were storong immunoreactivy of TGF-$\beta$. Also, in 1 and 2 day, TGF-$\beta$ was showed in white mater as well as gray mater, but in 3 day, only showed in gray mater. These data may suggests to the establishment of laser irradiation on spinal cord for skeletal muscle injury.

• Clinical and Experimental Pediatrics
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• 제46권7호
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• pp.702-709
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• 2003

목 적 : $IFN{\gamma}$는 다양한 암세포에서 $TNF{\alpha}$와 FAS/CD95 수용체 발현을 증가시키거나 caspase나 Bcl-2 가족의 활성화를 조절하여 $TNF{\alpha}$와 FAS/FASL 유도성 세포고사를 촉진한다. 신경모세포종에서 $IFN{\gamma}$와 $TNF{\alpha}$는 협동적으로 세포 분화를 유도하거나 성장 억제를 일으킨다. 또한 일부 신경모세포종에서 자연적인 FAS 수용체 발현에도 불구하고 그 리간드 자극에 의한 세포고사 유도에는 실패하였고 $IFN{\gamma}$ 투여로 이를 극복할 수 있음이 보고되었다. 본 연구에서는 $IFN{\gamma}$가 $TNF{\alpha}$나 길항적 FAS/CD95 항체 유도성 세포고사를 촉진할 수 있는지 여부를 다양한 항암제에 대한 내성을 가지고 있는 신경모세포종 세포주를 이용하여 알아보았다. 방 법 : CHLA-15, CHLA-90와 LA-N-2 신경모세포종 세포주를 IMDM 배지로 배양하였고 유전자 재조합 $IFN{\gamma}$, $TNF{\alpha}$, 길항적 FAS/CD95 항체(CH-11)를 투여하였다. 세포 생존율은 형광기질인 calcein-AM을 이용한 DIMSCAN을 통하여 측정하였고, 세포고사 정도는 Annexin V-PE와 7-ADD염색을 이용한 유식세포 분석기를 통하여 분석하였고 pancaspase and caspase-8 억제 실험을 통하여 확인하였다. TNF와 FAS/CD95 수용체 표현은 각각에 대한 단클론 항체와 PE가 결합된 이차 항체를 이용하여 유식세포 분석기로 알아보았다. 결 과 : $IFN{\gamma}$ 또는 $TNF{\alpha}$ 단독 투여로는 모든 세포주에서 의의있는 세포 독성을 유도하지 못 했으나 $IFN{\gamma}$와 $TNF{\alpha}$을 병행 투여시에는 CHLA-15과 CHLA-90 세포주에서 의의있는 세포 생존율 감소와 공통 capase경로를 통한 세포고사를 협동적으로 촉진하였다. 또한 길항적 FAS/CD95 항체 단독 투여 시에는 모든 세포주에서 세포 생존율의 변화가 없었으나 $IFN{\gamma}$ 전 처치 후 투여 시에는 CHLA-90 세포주에서 현저한 세포 생존율 변화 및 세포고사를 유도하였다. $INF{\gamma}$ 치료 후 TNFRI와 FASR의 발현이 모든 세포주에서 현저히 증가하였는데 이는 일부 감수성이 있는 신경모세포종에서 $INF{\gamma}$에 의한 $TNF{\alpha}$와 FAS/CD95수용체 유도성 세포고사 촉진의 한 기전이 될 것으로 사료된다. 결 론: 일부 신경모세포종에서 $IFN{\gamma}$가 $TNF{\alpha}$와 길항적 FAS/CD95 항체 유도성 세포고사를 감작화 시켰으며 이는 수용체 발현의 증가와 동반되었다.