A Mouse Model to Assess Innate Immune Response to &lt;em&gt;Staphylococcus aureus&lt;/em&gt; Infection

Anderson, Leif S.; Reynolds, Mack B.; Rivara, Kathryn R.; Miller, Lloyd S.; Simon, Scott I.

doi:10.3791/59015-v

Cited by 3 publications

(1 citation statement)

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“…Good co-localization between FITC-conjugated antimouse F4/80 and red autofluorescence suggested that red autofluorescence may be specific to macrophages (Figure 1A-B). We further used C57BL/6J-c2J-LysM-eGFP transgenic mice [29] to confirm whether this characteristic red autofluorescence can specifically identify macrophages, in which the GFP expression is driven by the lysozyme promoter (Figure S1A-B). In the freshly isolated epididymal fat, we found GFPpositive cells emit 1040-nm excited red autofluorescence (Figure 1C-D).…”

Section: Lipofuscin-like Fluorescence Label-free Marks the Spatial Lo...mentioning

confidence: 99%

Label-free optical metabolic imaging of adipose tissues for prediabetes diagnosis

Chen¹,

Qin²,

Liu³

et al. 2023

Theranostics

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Rationale: Prediabetes can be reversed through lifestyle intervention, but its main pathologic hallmark, insulin resistance (IR), cannot be detected as conveniently as blood glucose testing. In consequence, the diagnosis of prediabetes is often delayed until patients have hyperglycemia. Therefore, developing a less invasive diagnostic method for rapid IR evaluation will contribute to the prognosis of prediabetes. Adipose tissue is an endocrine organ that plays a crucial role in the development and progression of prediabetes. Label-free visualizing the prediabetic microenvironment of adipose tissues provides a less invasive alternative for the characterization of IR and inflammatory pathology. Methods: Here, we successfully identified the differentiable features of prediabetic adipose tissues by employing the metabolic imaging of three endogenous fluorophores NAD(P)H, FAD, and lipofuscin-like pigments.Results: We discovered that 1040-nm excited lipofuscin-like autofluorescence could mark the location of macrophages. This unique feature helps separate the metabolic fluorescence signals of macrophages from those of adipocytes. In prediabetes fat tissues with IR, we found only adipocytes exhibited a low redox ratio of metabolic fluorescence and high free NAD(P)H fraction a1. This differential signature disappears for mice who quit the high-fat diet or high-fat-high-sucrose diet and recover from IR. When mice have diabetic hyperglycemia and inflamed fat tissues, both adipocytes and macrophages possess this kind of metabolic change. As confirmed with RNA-seq analysis and histopathology evidence, the change in adipocyte's metabolic fluorescence could be an indicator or risk factor of prediabetic IR. Conclusion:Our study provides an innovative approach to diagnosing prediabetes, which sheds light on the strategy for diabetes prevention.

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Section: Lipofuscin-like Fluorescence Label-free Marks the Spatial Lo...mentioning

confidence: 99%

Label-free optical metabolic imaging of adipose tissues for prediabetes diagnosis

Chen¹,

Qin²,

Liu³

et al. 2023

Theranostics

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Clinically representative rodent model for biomedical device-associated infection

Lee

Choi

2023

Med Biol Sci Eng

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Bacterial biofilms in the body commonly occur following the implantation of a biomedical device. A mature biofilm results in an extracellular matrix covering the aggregated bacteria and provides protection against antibiotics or the native immune system, rendering diagnosis and treatment difficult. Experiments to eradicate or prevent biofilm formation have been widely performed, with many showing potential for application in vivo. To test the safety and in vivo efficacy of these novel methods, a reliable preclinical animal model is necessary. Here we developed a simple animal model that can be used to recreate medical device-associated infections in vivo. Reproducible Staphylococcus aureus bacterial biofilms were formed on a titanium implant and confirmed by the counting of colony-forming units after sonication and in vivo bioluminescence measurements. We tested our strategy for developing both acute and late-onset infections and confirmed that the model successfully demonstrated bacterial biofilm formation on titanium surfaces, representing acute infection. We believe that this model will be a good option for validating the efficacy and safety of antibacterial strategies for orthopedic surgery.

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Regulation of Lysozyme Activity by Human Hormones

Pankratov

Ганнесен

Nikolaev

2023

IBJ

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Background: Lysozyme is a part of human and animal noncellular immunity. The regulation of its activity by hormones is poorly studied. The aim of this study was to test the in vitro activity of lysozyme in the presence of catecholamines, natriuretic hormones, and E2. Methods: Hormones were incubated with lysozyme, and the activity of lysozome was further determined using a test culture of Micrococcus luteus in the early exponential growth stage. The activity of lysozyme was assessed based on the rate of change in the OD of the test culture. Molecular docking was performed using SwissDock server (http://www.swissdock.ch/docking), and molecular structures were further analyzed and visualized in the UCSF Chimera 1.15rc software. Results: According to the results, EPN and NE increased lysozyme activity up to 180% compared to the hormone-free enzyme. Changing the pH of the medium from 6.3 to 5.5, increased the lysozyme activity in the presence of E2 up to 150-200 %. The results also showed that exposure to hormones could modify lysozyme activity, and this effect depends on the temperature and pH value. The molecular docking revealed a decrease in the activation energy of the active site of enzyme during the interaction of catecholamines with the amino acid residues, asp52 and glu35 of the active site. Conclusion: Our findings demonstrate an additional mechanism for the involvement of lysozyme in humoral regulation of nonspecific immunity with respect to human pathogenic microflora and bacterial skin commensals by direct modulation of its activity using human hormones.

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A Mouse Model to Assess Innate Immune Response to <em>Staphylococcus aureus</em> Infection

Cited by 3 publications

References 0 publications

Label-free optical metabolic imaging of adipose tissues for prediabetes diagnosis

Label-free optical metabolic imaging of adipose tissues for prediabetes diagnosis

Clinically representative rodent model for biomedical device-associated infection

Regulation of Lysozyme Activity by Human Hormones

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