EphA2 Receptor Signaling Mediates Inflammatory Responses in Lipopolysaccharide-Induced Lung Injury

( Ji Young Hong ),( Mi Hwa Shin ),( Kyung Soo Chung ),( Eun Young Kim ),( Ji Ye Jung ),( Young Ae Kang ),( Young Sam Kim ),( Se Kyu Kim ),( Joon Chang ),( Moo Suk Park ) 대한결핵 및 호흡기학회 2015 Tuberculosis and Respiratory Diseases Vol.78 No.3

Background: Eph receptors and ephrin ligands have several functions including angiogenesis, cell migration, axon guidance, fluid homeostasis, oncogenesis, inflammation and injury repair. The EphA2 receptor potentially mediates the regulation of vascular permeability and inflammation in response to lung injury. Methods: Mice were divided into 3 experimental groups to study the role of EphA2 signaling in the lipopolysaccharide (LPS) -induced lung injury model i.e., IgG+phosphate-buffered saline (PBS) group (IgG instillation before PBS exposure), IgG+LPS group (IgG instillation before LPS exposure) and EphA2 monoclonal antibody (mAb)+LPS group (EphA2 mAb pretreatment before LPS exposure). Results: EphA2 and ephrinA1 were upregulated in LPS-induced lung injury. The lung injury score of the EphA2 mAb+LPS group was lower than that of the IgG+LPS group (4.30±2.93 vs. 11.45±1.20, respectively; p=0.004). Cell counts (EphA2 mAb+LPS: 11.33×104±8.84×104 vs. IgG+LPS: 208.0×104±122.6×104; p=0.018) and total protein concentrations (EphA2 mAb+LPS: 0.52±0.41 mg/mL vs. IgG+LPS: 1.38±1.08 mg/mL; p=0.192) were decreased in EphA2 mAb+LPS group, as compared to the IgG+LPS group. In addition, EphA2 antagonism reduced the expression of phospho-p85, phosphoinositide 3-kinase 110γ, phospho-Akt, nuclear factor κB, and proinflammatory cytokines. Conclusion: This results of the study indicated a role for EphA2-ephrinA1 signaling in the pathogenesis of LPS-induced lung injury. Furthermore, EphA2 antagonism inhibits the phosphoinositide 3-kinase-Akt pathway and attenuates inflammation.

EphrinA1/EphA2 Promotes Epithelial Hyperpermeability Involving in Lipopolysaccharide-induced Intestinal Barrier Dysfunction

( Yuhua Chen ),( Lei Zhang ),( Yongbo Zhang ),( Tao Bai ),( Jun Song ),( Wei Qian ),( Xiaohua Hou ) 대한소화기기능성질환·운동학회(구 대한소화관운동학회) 2020 Journal of Neurogastroenterology and Motility (JNM Vol.26 No.3

Background/Aims Lipopolysaccharide (LPS) is the key factor inducing mucosal and systemic inflammation in various intestinal and parenteral diseases, which could initially disrupt the epithelial barrier function. EphrinA1/ephA2 is speculated to increase the epithelial permeability for its “repulsive interaction” between adjacent cells. This study aim to investigate the role of ephrinA1/ephA2 in LPS-induced epithelial hyperpermeability. Methods In vivo model challenged with oral LPS in C57BL/6 mice and in vitro model exposed to LPS in Caco2 monolayer were established. The barrier function was assessed including expression of tight junction proteins (occludin and claudin-1), transepithelial electrical resistance, and permeability to macromolecules (fluorescein isothiocyanate-labeled fluorescent dextran 4 kDa [FD4]). Moreover, the expression and phosphorylation of ephrinA1/ephA2 were quantified, and its roles in the process of epithelial barrier disruption were confirmed via stimulating ephA2 with ephrinA1-Fc chimera (ephrinA1-Fc) and inactivating ephA2 with ephA2-Fc chimera (ephA2-Fc), or ephA2 monoclonal antibody (ephA2-mab), as well as inhibiting extracellular signal-regulated kinase 1/2 (ERK1/2) with PD98059. Results LPS induced significant barrier dysfunction with dismissed occludin and claudin-1 expression, reduced transepithelial electrical resistance and increased FD4 permeability, accompanied by upregulated ephrinA1/ephA2 pathway and phosphorylation of ephA2 receptor. Furthermore, ephA2-Fc, and ephA2-mab ameliorated LPS-induced epithelial hyperpermeability, which was also inhibited by PD98059. Additionally, ephrinA1-Fc led to apparent epithelial leakage in Caco2 monolayer by promoting the phosphorylation of ERK1/2, which could be obviously blocked by ephA2-mab and PD98059. Conclusion EphrinA1/ephA2 promotes epithelial hyperpermeability with an ERK1/2-dependent pathway, which involves in LPS-induced intestinal barrier dysfunction. (J Neurogastroenterol Motil 2020;26:397-409)

Protective Effect of Niclosamide on Lipopolysaccharide-induced Sepsis in Mice by Modulating STAT3 Pathway

JANG Se Gwang 대한임상검사과학회 2023 대한임상검사과학회지(KJCLS) Vol.55 No.4

Sepsis is a systemic inflammatory response, with manifestations in multiple organs by pathogenic infection. Currently, there are no promising therapeutic strategies. Signal transducer and activator of transcription 3 (STAT3) is a cell signaling transcription factor. Niclosamide is an anti-helminthic drug approved by the Food and Drug Administration (FDA) as a potential STAT3 inhibitor. C57BL/6 mice were treated with an intraperitoneal injection of lipopolysaccharide (LPS). Niclosamide was administered orally 2 hours after the LPS injection. This study found that Niclosamide improved the survival and lung injury of LPS-induced mice. Niclosamide decreased the levels of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β), aspartate aminotransferase (AST), alanine aminotransferase (ALT), and lactate dehydrogenase (LDH) in serum. The effects of Niclosamide on phosphoinositide 3-kinase (PI3K), AKT, nuclear factor-κB (NF-κB), and STAT3 signaling pathways were determined in the lung tissue by immunoblot analysis. Niclosamide reduced phosphorylation of PI3K, AKT, NF-κB, and STAT3 significantly. Furthermore, it reduced the phosphorylation of STAT3 by LPS stimulation in RAW 264.7 macrophages. Niclosamide also reduced the LPS-stimulated expression of proinflammatory mediators, including IL-6, TNF-α, and IL-1β. Niclosamide provides a new therapeutic strategy for murine sepsis models by suppressing the inflammatory response through STAT3 inhibition.

FOCUSED REVIEWS: GUT AND BASIC RESEARCH : Lipopolysaccharide: Basic Biochemistry, Intracellular Signaling, and Physiological Impacts in the Gut

( Sang Hoon Rhee ) 대한장연구학회 2014 Intestinal Research Vol.12 No.2

Lipopolysaccharide (LPS), a main constituent of Gram-negative bacterial membrane, specifically activates Toll-like receptor 4, leading to the production of pleiotropic cytokines/chemokines which in turn regulate inflammatory and innate and subsequent adaptive immune responses. Given that human gut harbors a large collection of commensal bacteria, LPS released by gut microbes is able to make the great impact on gut homeostasis through the intracellular signaling pathways engaged by host-microbial interaction. Emerging evidence indicates that LPS in the gut has a potency to elicit the pathogenesis of intestinal inflammatory diseases such as inflammatory bowel disease and necrotizing enterocolitis. In this review, we discuss the current understanding of the basic biochemistry of LPS, LPS-induced intracellular signaling, and physiological impacts of LPS in the intestine. (Intest Res 2014;12:90-95)

사람 치주인대세포에서 Lipopolysaccharide와 니코틴으로 유도된 iNOS와 COX-2 발현에 NFATc의 관여

이상임 ( Sang Im Lee ),유지수 ( Ji Su Yu ) 한국치위생과학회 2015 치위생과학회지 Vol.15 No.6

Although nuclear factor of activated T cell (NFAT) plays a key role in inflammation, its anti-inflammatory effects and mechanism of action in periodontitis are still unknown. This study aimed to identify the effects of NFAT on the proinflammatory mediators activated by lipopolysaccharide (LPS) plus nicotine stimulation in human periodontal ligament cells (hPDLCs). The production of nitric oxide (NO) and prostaglandin E2 (PGE2) was evaluated using Griess reagent and an enzyme immunoassay, respectively. The expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2) and NFAT proteins was evaluated by Western blot analysis. LPS plus nicotine synergistically induced the production of NO and PGE2 and increased the protein expression of iNOS, COX-2 and NFAT. Treatment with an NFAT inhibitor blocked the LPS plus nicotine-stimulated NO and PGE2 release as well as the expression of iNOS and COX-2. Our data suggest that the LPS plus nicotine-induced inflammatory effects on hPDLCs may act through a novel mechanism involving the action of NFAT. Thus, NFAT may provide a potential therapeutic target for the treatment of periodontal disease associated with smoking and dental plaque.

The Effects of Flecainide Acetate on Inflammatory-Immune Response in Lipopolysaccharide-Stimulated Neutrophils and on Mortality in Septic Rats

Shi Young Chung,Jinyoung Kim,Hong Bum Bae,Tran Duc Tin,Wan Ju,Sang Hyun Kwak 대한중환자의학회 2018 Acute and Critical Care Vol.33 No.1

Background: Flecainide acetate is a drug used primarily for cardiac arrhythmia. Some studies also imply that flecainide acetate has the potential to regulate inflammatory-immune responses; however, its mechanism of action is contended. We determined the effects of flecainide acetate on lipopolysaccharide (LPS)-stimulated human neutrophils in vitro and on mortality in a septic rat model. Methods: Neutrophils from human blood were cultured with varying concentrations of flecainide acetate (1 μM, 10 μM, or 100 μM) with or without LPS (100 ng/ml). To assess neutrophil activation, the protein levels of tumor necrosis factor-alpha (TNF-α) and interleukin (IL)-6 and IL-8 were measured after a 4-hour culture period. To assess the intracellular signaling pathways, the levels of phosphorylation of p38 mitogen-activated protein kinase (p38), extracellular signal-regulated kinase (ERK) 1/2, and c-Jun N-terminal kinase (JNK) were measured after a 30-minute culture period, and the nuclear translocation of nuclear factor (NF)-κB was measured after a 1-hour culture period. Additionally, the survival rate was investigated in a rat sepsis model. Results: Flecainide acetate down-regulated the activation of proinflammatory cytokines, including TNF-α and IL-6 and IL-8, and intracellular signaling pathways including ERK 1/2 and NF-κB. Flecainide acetate also improved the survival rate in the rat sepsis model. Conclusions: Collectively, these findings indicate that flecainide acetate can improve survival in a rat sepsis model by attenuating LPS-induced neutrophil responses. We therefore suggest that flecainide acetate plays an important role in modulating inflammatoryimmune responses.

EphA2 Receptor Signaling Mediates Inflammatory Responses in Lipopolysaccharide-Induced Lung Injury

홍지영,신미화,정경수,김은영,정지예,강영애,김영삼,김세규,장준,박무석 대한결핵및호흡기학회 2015 Tuberculosis and Respiratory Diseases Vol.78 No.3

Background: Eph receptors and ephrin ligands have several functions including angiogenesis, cell migration, axon guidance, fluid homeostasis, oncogenesis, inflammation and injury repair. The EphA2 receptor potentially mediates the regulation of vascular permeability and inflammation in response to lung injury. Methods: Mice were divided into 3 experimental groups to study the role of EphA2 signaling in the lipopolysaccharide (LPS) -induced lung injury model i.e., IgG+phosphate-buffered saline (PBS) group (IgG instillation before PBS exposure), IgG+LPS group (IgG instillation before LPS exposure) and EphA2 monoclonal antibody (mAb)+LPS group (EphA2 mAb pretreatment before LPS exposure). Results: EphA2 and ephrinA1 were upregulated in LPS-induced lung injury. The lung injury score of the EphA2 mAb+LPS group was lower than that of the IgG+LPS group (4.30±2.93 vs. 11.45±1.20, respectively; p=0.004). Cell counts (EphA2 mAb+LPS: 11.33×104±8.84×104 vs. IgG+LPS: 208.0×104±122.6×104; p=0.018) and total protein concentrations (EphA2 mAb+LPS: 0.52±0.41 mg/mL vs. IgG+LPS: 1.38±1.08 mg/mL; p=0.192) were decreased in EphA2 mAb+LPS group, as compared to the IgG+LPS group. In addition, EphA2 antagonism reduced the expression of phospho-p85, phosphoinositide 3-kinase 110γ, phospho-Akt, nuclear factor κB, and proinflammatory cytokines. Conclusion: This results of the study indicated a role for EphA2-ephrinA1 signaling in the pathogenesis of LPS-induced lung injury. Furthermore, EphA2 antagonism inhibits the phosphoinositide 3-kinase–Akt pathway and attenuates inflammation.

EphA2 Receptor Signaling Mediates Inflammatory Responses in Lipopolysaccharide-Induced Lung Injury

Hong, Ji Young,Shin, Mi Hwa,Chung, Kyung Soo,Kim, Eun Young,Jung, Ji Ye,Kang, Young Ae,Kim, Young Sam,Kim, Se Kyu,Chang, Joon,Park, Moo Suk The Korean Academy of Tuberculosis and Respiratory 2015 Tuberculosis and Respiratory Diseases Vol.78 No.3

Background: Eph receptors and ephrin ligands have several functions including angiogenesis, cell migration, axon guidance, fluid homeostasis, oncogenesis, inflammation and injury repair. The EphA2 receptor potentially mediates the regulation of vascular permeability and inflammation in response to lung injury. Methods: Mice were divided into 3 experimental groups to study the role of EphA2 signaling in the lipopolysaccharide (LPS)-induced lung injury model i.e., IgG+phosphate-buffered saline (PBS) group (IgG instillation before PBS exposure), IgG+LPS group (IgG instillation before LPS exposure) and EphA2 monoclonal antibody (mAb)+LPS group (EphA2 mAb pretreatment before LPS exposure). Results: EphA2 and ephrinA1 were upregulated in LPS-induced lung injury. The lung injury score of the EphA2 mAb+LPS group was lower than that of the IgG+LPS group ($4.30{\pm}2.93$ vs. $11.45{\pm}1.20$, respectively; p=0.004). Cell counts (EphA2 mAb+LPS: $11.33{\times}10^4{\pm}8.84{\times}10^4$ vs. IgG+LPS: $208.0{\times}10^4{\pm}122.6{\times}10^4$; p=0.018) and total protein concentrations (EphA2 mAb+LPS: $0.52{\pm}0.41mg/mL$ vs. IgG+LPS: $1.38{\pm}1.08mg/mL$; p=0.192) were decreased in EphA2 mAb+LPS group, as compared to the IgG+LPS group. In addition, EphA2 antagonism reduced the expression of phospho-p85, phosphoinositide 3-kinase $110{\gamma}$, phospho-Akt, nuclear factor ${\kappa}B$, and proinflammatory cytokines. Conclusion: This results of the study indicated a role for EphA2-ephrinA1 signaling in the pathogenesis of LPS-induced lung injury. Furthermore, EphA2 antagonism inhibits the phosphoinositide 3-kinase-Akt pathway and attenuates inflammation.

Lipopolysaccharide: Basic Biochemistry, Intracellular Signaling, and Physiological Impacts in the Gut

이상훈 대한장연구학회 2014 Intestinal Research Vol.12 No.2

Lipopolysaccharide (LPS), a main constituent of Gram-negative bacterial membrane, specifically activates Toll-like receptor4, leading to the production of pleiotropic cytokines/chemokines which in turn regulate inflammatory and innate and subsequentadaptive immune responses. Given that human gut harbors a large collection of commensal bacteria, LPS released bygut microbes is able to make the great impact on gut homeostasis through the intracellular signaling pathways engaged byhost-microbial interaction. Emerging evidence indicates that LPS in the gut has a potency to elicit the pathogenesis of intestinalinflammatory diseases such as inflammatory bowel disease and necrotizing enterocolitis. In this review, we discuss the currentunderstanding of the basic biochemistry of LPS, LPS-induced intracellular signaling, and physiological impacts of LPS in the intestine.

위장관 ; Lipopolysaccharide로 유도된 HT-29 세포주의 염증에서 Lactobacillus rhamnosus GG의 항염증 작용과 기전

이상길 ( Sang Kil Lee ),양경민 ( Kyung Min Yang ),천재희 ( Jae Hee Cheon ),김태일 ( Tae Il Kim ),김원호 ( Won Ho Kim ) 대한소화기학회 2012 대한소화기학회지 Vol.60 No.2

Background/Aims: Probiotics are live non-pathogenic organisms that belong to the resident microflora, and confer health benefits by multiple mechanisms. Lactobacillus rhamnosus GG (LGG) is one of the probiotic bacteria that ameliorates intestinal injury and inflammation caused by various stimuli. We aimed to evaluate the anti-inflammatory effect and mechanism of LGG in lipopolysaccharide (LPS)-stimulated HT-29 cells. Methods: HT-29 cells were stimulated with interleukin (IL)-1β (2 ng/mL), tumor necrosis factor (TNF)-α (20 ng/mL), and LPS (20 μg/mL) in the presence or absence of LGG (107-109 colony forming units/mL). Production of the pro-inflammatory chemokine IL-8 was measured by ELISA and semi-quantitative PCR. Transcriptional activity of NF-κB-responsive gene was evaluated by luciferase assay with reporter gene. Toll-like receptor 4 (TLR4) mRNA expression was assessed by semi-quantitative PCR. The IκBα degradation was evaluated by western blot and intranuclear translocation of NF-κB was determined by western blot and immunofluorescence. Results: LGG did not affect the viability of HT-29 cells. Pretreatment of HT-29 cells with LGG significantly blocked TNF-α, and LPS induced IL-8 activation at both mRNA and protein level (p<0.05). Pretreatment of HT-29 cells with LGG attenuated LPS-induced NF-κB nuclear translocation and also blocked LPS-induced IκBα degradation. LGG also down-regulated TLR4 mRNA activated by LPS. Conclusions: LGG attenuates LPS induced inflammation, and this may be associated with TLR4/NF-κB down-regulation. (Korean J Gastroenterol 2012;60:86-93)