AUTHOR=Guerrero-Juarez Christian F. , Schilf Paul , Li Jing , Zappia Maria Paula , Bao Lei , Patel Payal M. , Gieseler-Tillmann Jenny , Murthy Sripriya , Cole Connor , Sverdlov Maria , Frolov Maxim V. , Hashimoto Takashi , Ishii Norito , Rülicke Thomas , Bieber Katja , Ludwig Ralf J. , Sadik Christian D. , Amber Kyle T. 

TITLE=C-type lectin receptor expression is a hallmark of neutrophils infiltrating the skin in epidermolysis bullosa acquisita

JOURNAL=Frontiers in Immunology

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2023.1266359

DOI=10.3389/fimmu.2023.1266359

ISSN=1664-3224

ABSTRACT=<sec><title>Introduction</title><p>Inflammatory epidermolysis bullosa acquisita (EBA) is characterized by a neutrophilic response to anti-type VII collagen (COL7) antibodies resulting in the development of skin inflammation and blistering. The antibody transfer model of EBA closely mirrors this EBA phenotype.</p></sec><sec><title>Methods</title><p>To better understand the changes induced in neutrophils upon recruitment from peripheral blood into lesional skin in EBA, we performed single-cell RNA-sequencing of whole blood and skin dissociate to capture minimally perturbed neutrophils and characterize their transcriptome.</p></sec><sec><title>Results</title><p>Through this approach, we identified clear distinctions between circulating activated neutrophils and intradermal neutrophils. Most strikingly, the gene expression of multiple C-type lectin receptors, which have previously been reported to orchestrate host defense against fungi and select bacteria, were markedly dysregulated. After confirming the upregulation of <italic>Clec4n</italic>, <italic>Clec4d</italic>, and <italic>Clec4e</italic> in experimental EBA as well as in lesional skin from patients with inflammatory EBA, we performed functional studies in globally deficient <italic>Clec4e<sup>−/−</sup></italic> and <italic>Clec4d<sup>−/−</sup></italic> mice as well as in neutrophil-specific <italic>Clec4n<sup>−/−</sup></italic> mice. Deficiency in these genes did not reduce disease in the EBA model.</p></sec><sec><title>Discussion</title><p>Collectively, our results suggest that while the upregulation of <italic>Clec4n</italic>, <italic>Clec4d</italic>, and <italic>Clec4e</italic> is a hallmark of activated dermal neutrophil populations, their individual contribution to the pathogenesis of EBA is dispensable.</p></sec>