Two-photon Intravital Imaging of Leukocytes During the Immune Response in Lipopolysaccharide-treated Mouse Liver

Park, Sang A; Choe, Young Ho; Lee, Sung Hwan; Hyun, Young-Min

doi:10.3791/57191

Cited by 8 publications

(7 citation statements)

References 10 publications

(10 reference statements)

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“…The mouse's liver was carefully attached on the silicon bed for fixation. The cover glass was placed on the fixed liver and imaging was performed [15].…”

Section: Methodsmentioning

confidence: 99%

PM2.5 Exposure in the Respiratory System Induces Distinct Inflammatory Signaling in the Lung and the Liver of Mice

Jeong

Park

et al. 2019

Journal of Immunology Research

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Fine particulate matter 2.5 (PM2.5) is a harmful air pollutant currently threatening public health. Although many studies have been performed on the general negative effects of PM2.5 in mice and humans, the migration patterns of various immune cells in response to PM2.5 exposure remain unclear. In this study, we aimed to investigate the immune cell migratory response in the lung and the liver of intratracheally PM2.5-inoculated mice. To investigate the migration trajectory of immune cells in the lung and the liver tissues of mice, we employed microscopic tools including two-photon intravital imaging, histological analysis, and transmission electron microscopy. Our data from two-photon intravital imaging showed that there was no significant difference in the number of infiltrated neutrophils in the lung and the liver of PM2.5-treated mice, compared to the nontreated condition. However, from the histological analysis and the transmission electron microscopy after vascular perfusion to remove intravascular leukocytes, we observed that some leukocytes were frequently observed in the lung and the liver of PM2.5-treated mice. Interestingly, quantification of leukocyte population using flow cytometry showed significant increase of neutrophils and macrophages in the lung, but not much in the liver, 24 h post-PM2.5 treatment. These data imply that two-photon intravital imaging of the lung and the liver actually visualized neutrophils, which were adherent to the luminal side of the vasculature. We then conducted mRNA microarray analysis to further observe how PM2.5 affects gene expression patterns in the lung and the liver. PM2.5 treatment changed the mRNA expression associated with the IL-17 signaling pathway in the lung and changed the mRNA expression associated with metabolic pathways in the liver. In summary, these results suggest that the immune response in the lung is distinctly regulated from that in the liver under acute PM2.5-induced inflammation and that these organs consequently are regulated via distinct signaling pathways.

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“…The mouse's liver was carefully attached on the silicon bed for fixation. The cover glass was placed on the fixed liver and imaging was performed [15].…”

Section: Methodsmentioning

confidence: 99%

PM2.5 Exposure in the Respiratory System Induces Distinct Inflammatory Signaling in the Lung and the Liver of Mice

Jeong

Park

et al. 2019

Journal of Immunology Research

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“…We previously described a staging system and two-photon microscopy to obtain imaging data from the live mouse liver [15,16]. Two-photon microscopy and Zen software (Carl-Zeiss, Oberkochen, Germany) were used for mouse imaging with an imaging chamber.…”

Section: Two-photon Intravital Imaging Of Mouse Livermentioning

confidence: 99%

In vivo monitoring of dynamic interaction between neutrophil and human umbilical cord blood-derived mesenchymal stem cell in mouse liver during sepsis

Maeng

Kim

et al. 2020

Stem Cell Res Ther

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Background: Sepsis is a global inflammatory disease that causes death. It has been reported that mesenchymal stem cell (MSC) treatment can attenuate inflammatory and septic symptoms. In this study, we investigated how interactions between neutrophils and human umbilical cord blood (hUCB)-MSCs in the liver of septic mice are involved in mitigating sepsis that is mediated by MSCs. Accordingly, we aimed to determine whether hUCB-MSC application could be an appropriate treatment for sepsis. Methods: To induce septic condition, lipopolysaccharide (LPS) was intraperitoneally (i.p.) injected into mice 24 h after the intravenous (i.v.) injection of saline or hUCB-MSCs. To determine the effect of hUCB-MSCs on the immune response during sepsis, histologic analysis, immunoassays, and two-photon intravital imaging were performed 6 h post-LPS injection. For the survival study, mice were monitored for 6 days after LPS injection. Results: The injection (i.v.) of hUCB-MSCs alleviated the severity of LPS-induced sepsis by increasing IL-10 levels (p < 0.001) and decreasing mortality (p < 0.05) in septic mice. In addition, this significantly reduced the recruitment of neutrophils (p < 0.001) to the liver. In hUCB-MSC-treated condition, we also observed several distinct patterns of dynamic interactions between neutrophils and hUCB-MSCs in the inflamed mouse liver, as well as vigorous interactions between hepatic stellate cells (HSCs or ito cells) and hUCB-MSCs. Interestingly, hUCB-MSCs that originated from humans were not recognized as foreign in the mouse body and consequently did not cause graft rejection. Conclusions: These distinct interaction patterns between innate immune cells and hUCB-MSCs demonstrated that hUCB-MSCs have beneficial effects against LPS-induced sepsis through associations with neutrophils. In addition, the immunomodulatory properties of hUCB-MSCs might enable immune evasion in the host. Taken together, our results suggest the prospects of hUCB-MSCs as a therapeutic tool to inhibit inflammation and alleviate pathological immune responses such as sepsis.

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“…C57BL/6 mice (Orient Bio, Korea) and LysM-green fluorescent protein (GFP) mice ( Faust et al, 2000 ) were maintained in a specific pathogen-free environment at Avison Biomedical Research Center at the Yonsei University College of Medicine. The sepsis mouse model was induced by intraperitoneal injection with LPS (10 mg/kg; Salmonella , Sigma, St. Louis, MO, United States) for 48 h, which was modified from previous reports ( Park et al, 2018 ; Ahn et al, 2020 ). Two hours after LPS inoculation, 18:0 LPC (10 mg/kg; Avanti Polar Lipids, Birmingham, AL, United States) was subcutaneously injected at different sites four times at 12 h intervals for 48 h. All animal experiments were approved by the Institutional Animal Care and Use Committee of the Yonsei University College of Medicine (IACUC No.…”

Section: Methodsmentioning

confidence: 99%

Lysophosphatidylcholine Alleviates Acute Lung Injury by Regulating Neutrophil Motility and Neutrophil Extracellular Trap Formation

Jeong

Kim

Byun

et al. 2022

Front. Cell Dev. Biol.

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Sepsis is predominantly initiated by bacterial infection and can cause systemic inflammation, which frequently leads to rapid death of the patient. However, this acute systemic inflammatory response requires further investigation from the perspectives of clinical judgment criteria and early treatment strategies for the relief of symptoms. Lysophosphatidylcholine (LPC) 18:0 may relieve septic symptoms, but the relevant mechanism is not clearly understood. Therefore, we aimed to assess the effectiveness of LPC as a therapeutic treatment for acute inflammation in the lung induced by lipopolysaccharide in mice. Systemic inflammation of mice was induced by lipopolysaccharide (LPS) inoculation to investigate the role of LPC in the migration and the immune response of neutrophils during acute lung injury. By employing two-photon intravital imaging of the LPS-stimulated LysM-GFP mice and other in vitro and in vivo assays, we examined whether LPC alleviates the inflammatory effect of sepsis. We also tested the effect of LPC to human neutrophils from healthy control and sepsis patients. Our data showed that LPC treatment reduced the infiltration of innate immune cells into the lung. Specifically, LPC altered neutrophil migratory patterns and enhanced phagocytic efficacy in the damaged lung. Moreover, LPC treatment reduced the release of neutrophil extracellular trap (NET), which can damage tissue in the inflamed organ and exacerbate disease. It also reduced human neutrophil migration under inflammatory environment. Our results suggest that LPC can alleviate sepsis-induced lung inflammation by regulating the function of neutrophils. These findings provide evidence for the beneficial application of LPC treatment as a potential therapeutic strategy for sepsis.

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Two-photon Intravital Imaging of Leukocytes During the Immune Response in Lipopolysaccharide-treated Mouse Liver

Cited by 8 publications

References 10 publications

PM2.5 Exposure in the Respiratory System Induces Distinct Inflammatory Signaling in the Lung and the Liver of Mice

PM2.5 Exposure in the Respiratory System Induces Distinct Inflammatory Signaling in the Lung and the Liver of Mice

In vivo monitoring of dynamic interaction between neutrophil and human umbilical cord blood-derived mesenchymal stem cell in mouse liver during sepsis

Lysophosphatidylcholine Alleviates Acute Lung Injury by Regulating Neutrophil Motility and Neutrophil Extracellular Trap Formation

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