Ca2+ signalling is critical for autoantibody-induced blistering of human epidermis in pemphigus

T Schmitt; D T Egu; E Walter; A M Sigmund; R Eichkorn; A Yazdi; E Schmidt; M Sárdy; R Eming; M Goebeler; J Waschke

doi:10.1111/bjd.20091

Ca²⁺ signalling is critical for autoantibody-induced blistering of human epidermis in pemphigus

Br J Dermatol. 2021 Sep;185(3):595-604. doi: 10.1111/bjd.20091. Epub 2021 May 31.

Authors

T Schmitt¹, D T Egu¹, E Walter¹, A M Sigmund¹, R Eichkorn², A Yazdi^{2

3}, E Schmidt^{4

5}, M Sárdy⁶, R Eming⁷, M Goebeler⁸, J Waschke¹

Affiliations

¹ Ludwig-Maximilian-Universität München, Anatomische Anstalt, Lehrstuhl Anatomie I - Vegetative Anatomie, Pettenkoferstraße 11, München, D-80336, Germany.
² Department of Dermatology, University Medical Center Tübingen, Eberhard Karls-University, Tübingen, Germany.
³ Department of Dermatology, RWTH Aachen, Aachen, Germany.
⁴ Lübeck Institute of Experimental Dermatology (LIED), University of Lübeck, Lübeck, 23562, Germany.
⁵ Department of Dermatology, University of Lübeck, Lübeck, 23562, Germany.
⁶ Clinic for Dermatology, Semmelweis University, Budapest, Hungary.
⁷ Department of Dermatology and Allergology, Philipps-Universität Marburg, Marburg, Germany.
⁸ Department of Dermatology, Venereology and Allergology, University Hospital Würzburg, Würzburg, 97080, Germany.

PMID: 33792909
DOI: 10.1111/bjd.20091

Abstract

Background: Pemphigus is a severe bullous autoimmune skin disease. Pemphigus foliaceus (PF) is characterized by antidesmoglein (Dsg) 1 IgG causing epidermal blistering; mucosal pemphigus vulgaris (mPV) by anti-Dsg3 IgG inducing erosions in the mucosa; and mucocutaneous pemphigus vulgaris (PV) by affecting both, with autoantibodies targeting Dsg1 and Dsg3.

Objectives: To characterize the Ca²⁺ flux pathway and delineate its importance in pemphigus pathogenesis and clinical phenotypes caused by different antibody profiles.

Methods: Immunoprecipitation, Ca²⁺ flux analysis, Western blotting, immunofluorescence staining, dissociation assays and a human skin ex vivo model were used.

Results: PV IgG and PF IgG, but neither Dsg3-specific monoclonal antibody (AK23) nor mPV IgG, caused Ca²⁺ influx in primary human keratinocytes. Phosphatidylinositol 4-kinase α interacts with Dsg1 but not with Dsg3. Its downstream target - phospholipase-C-γ1 (PLC) - was activated by PV IgG and PF IgG but not AK23 or mPV IgG. PLC releases inositol 1,4,5-trisphosphate (IP3) causing IP3 receptor (IP3R) activation and Ca²⁺ flux from the endoplasmic reticulum into the cytosol, which stimulates Ca²⁺ release-activated channels (CRAC)-mediated Ca²⁺ influx. Inhibitors against PLC, IP3R and CRAC effectively blocked PV IgG and PF IgG-induced Ca²⁺ influx; ameliorated alterations of Dsg1 and Dsg3 localization, and reorganization of keratin and actin filaments; and inhibited loss of cell adhesion in vitro. Finally, inhibiting PLC or IP3R was protective against PV IgG-induced blister formation and redistribution of Dsg1 and Dsg3 in human skin ex vivo.

Conclusions: Ca²⁺ -mediated signalling is important for epidermal blistering and dependent on the autoantibody profile, which indicates different roles for signalling complexes organized by Dsg1 and Dsg3. Interfering with PLC and Ca²⁺ signalling may be a promising approach to treat epidermal manifestations of pemphigus.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Autoantibodies
Blister
Desmoglein 1
Desmoglein 3
Epidermis
Humans
Immunoglobulin G
Pemphigus*

Substances

Autoantibodies
Desmoglein 1
Desmoglein 3
Immunoglobulin G