Live imaging of cutaneous immune responses

Prof. Kenji Kabashima (Kyoto University, Japan) gave a visually stunning overview of the recent advances in intravital imaging techniques in mice, providing new avenues to study real-time molecular behaviour in intact tissues within a live organism [1].

The epidermis has >1,000 Langerhans cells per cm², and there are established mouse lines in which a fluorescent protein marks these cells. The monitoring of fluorescently labelled proteins and agents can be combined with autofluorescent properties of the microenvironment to provide a comprehensive snapshot of in vivo cell biology. Intravital or in vivo microscopy (IVM) has emerged as a powerful technique for the anatomical and functional mapping of cell biology in live mice from the subcellular level to whole-body approaches. The introduction of fluorescent proteins into mice by genetic engineering has opened exciting opportunities to track live cell biology and molecular dynamics in vivo. Combined IVM of fluorescent proteins with other fluorescently tagged probes, such as antibodies, drugs, or nanoparticles, while also exploring the inherent or autofluorescent properties of endogenous compounds, such as extracellular matrix or metabolites, can provide a comprehensive biological insight into live animals with an improved fidelity compared with cell and tissue-culture models. Furthermore, the use of multiphoton microscopy with pulsed infrared lasers provides key advantages for IVM as this can significantly extend the imaging depths owing to the reduced absorption and scattering at longer excitation wavelengths, while providing strong optical sectioning. Although Prof. Kabashima did not explore any single hypothesis in his talk, he demonstrated how his team uses models of ichthyosis vulgaris, among others, to video neutrophil activity and keratinocyte dynamics to gain exciting insights into the intricate regulation of live cell biology at the microscale level.

Figure: Psoriasiform dermatitis with a subcorneal pustule. Data on file.Haematoxylin and eosin stain, original magnification 4X

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   1. Kabashima K. O020 SPIN 2019, 25-27 April, Paris, France.

Posted on 21 June, 201924 March, 2021