Th2-directed interventions and characterization of cellular and molecular alterations in humanized mouse models of Pemphigus vulgaris
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Abstract
Pemphigus vulgaris (PV) pathogenesis arises at the interface of adaptive immune mechanisms characterized by the presence of high-affinity autoantibodies against desmogleins licensed by antigen-specific Th-cell support and keratinocyte adhesion systems whose composition and signaling thresholds determine susceptibility to acantholysis. Currently available mouse models of PV are unable to fully reflect the disease from break of immunological tolerance to visual and histological pathology at the skin level, despite induction of significant autoreactive anti-desmoglein 3 (Dsg3) antibody titers. Here, we are employing humanized mouse models to provide insight into the generation of a sustained pathogenic anti-Dsg3 response under inhibition of GATA-3 as the main differentiation factor for Th2 immune cells, as well as providing a deep cellular characterization of a novel transgenic mouse model expressing human Dsg3 (hDsg3) as a target for PV autoantibodies which represents pathologic features of human PV disease.
T helper type 2 (Th2) cells have been in the focus of PV-related research as crucial co-stimulators in the generation of anti-Dsg3 autoantibody responses for a while. Therefore, we investigated the effect of GATA-3 inhibition via antisense molecules (GATA-3-specific DNAzyme and Gapmer) on the polarization of Th2 cells in an HLA-humanized, human CD4-expressing mouse model (HLA-B6) for PV to determine how anti-hDsg3-antibody production, B cell class switching and affinity maturation might be affected. Analysis of the draining lymph node and splenic cells of HLA-B6 mice locally immunized with hDsg3 showed that, while a robust anti-hDsg3 antibody response was generated, a dominant Th2 signature could not be observed. However, a slight increase in Th1 cell levels and a notable increase in T regulatory cell (Treg) levels was identified. An Th2-independent modulation of antibody titer levels was observed under GATA-3-Gapmer treatment, which could most probably be attributed to CpG/TLR9-associated off-target effects that coincided with B-cell activation and expansion of CD93+ T1 B cells. Unfortunately, no changes could be determined for germinal center (GC) related cells, possibly due to late sampling windows of 21 and 42 days post-immunization.
To develop and characterize a new mouse model representing both the immunological onset and the ultimate pathogenic presentation of PV-like skin lesions, mice transgenic for the human Dsg3 (hDsg3-B6) were immunized by subcutaneous application of hDsg3 protein in complete Freund’s adjuvant (CFA). This approach resulted in a break of autologous immune tolerance shown by a robust and sustained anti-hDsg3 autoantibody response seen as early as 14 days after a single immunization dose. These mice showed typical features of PV lesions as suprabasal blistering in mucosal tissue. Further single cell transcriptome analyses of pre-lesional skin from hDsg3-B6 mice 15 days after immunization showed a distinct upregulation of an immediate-early/AP-1 program at the transcriptional level specifically within the basal and spinous cell populations bracketing the eventual suprabasal cleft region. Additionally, we found mouse-specific discrepancies in cadherin expression signatures and composition, that if compared to human mRNA levels in keratinocyte (sub-)populations, might explain why mouse models for PV are so notoriously difficult in eliciting the blistering phenotype. Specifically, Dsg1/2 and desmocollin intensity and spatial distribution are markedly different and could buffer acantholysis induction in mice.
Taken together, this work can provide further insights that straddle the gap in model to patient translation, providing a solid start to a translationally complete model for PV, encompassing all events from autoimmune induction to histological presentation, ultimately enabling improved mechanistic and therapeutic research in the future.
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Issued: 2026-03-26
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FB20:Medizin
Language
en
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Dermatology
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Pauck, Kim Aileen: Th2-directed interventions and characterization of cellular and molecular alterations in humanized mouse models of Pemphigus vulgaris. : 2026-03-26.
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