An Adult Passive Transfer Mouse Model to Study Desmoglein 3 Signaling in Pemphigus Vulgaris

Abstract

Evidence has accumulated that changes in intracellular signaling downstream of desmoglein 3 (Dsg3) may play a significant role in epithelial blistering in the autoimmune disease pemphigus vulgaris (PV). Currently, most studies on PV involve passive transfer of pathogenic antibodies into neonatal mice which have not finalized epidermal morphogenesis, and do not permit analysis of mature hair follicles (HFs) and stem cell niches. To investigate Dsg3 antibody-induced signaling in the adult epidermis at defined stages of the HF cycle, we here developed a model with passive transfer of the monospecific pathogenic Dsg3 antibody AK23 into adult 8-week-old C57Bl/6J mice. Validated using histopathological and molecular methods, we found that this model faithfully recapitulates major features described in PV patients and PV models. Two hours after AK23 transfer we observed widening of intercellular spaces between desmosomes and EGFR activation, followed by increased Myc expression and epidermal hyperproliferation, desmosomal Dsg3 depletion and predominant blistering in HFs and oral mucosa. These data confirm that the adult passive transfer mouse model is ideally suited for detailed studies of Dsg3 antibody-mediated signaling in adult skin, providing the basis for investigations on novel keratinocyte-specific therapeutic strategies.

Feasibility study for clinical application of caspase‐3 inhibitors in Pemphigus vulgaris

“…As expected, AK23 but not mIgG induced PV blisters in the bulge of telogen HFs. [9,10] The number of blistered HFs (n > 100 total HFs analysed per animal) was similar in wild-type and heterozygous mice with 77.3 ± 5.3% and 78.4 ± 5.6% HF blisters, respectively.…”

“…In the adult PV mouse model, characteristic blisters develop in response to AK23 in the stem cell niche (bulge) of resting telogen hair follicles (HFs) concurrently with increased proliferation. Furthermore, as in PV patients with Dsg3 antibodies, [10] blisters occur in mucous membranes such as the oral cavity while the epidermis remains intact. [11] All experiments were approved by the ethics committee, Canton Bern, Switzerland (BE2/15).…”

“…We applied the adult PV mouse model [10] to conditional K14 promoterdriven keratinocyte-specific caspase-3-deficient mice (casp3 EKO ) ( Fig. S1A; Appendix S1).…”

150thAnniversary Series: Desmosomes and Autoimmune Disease, Perspective of Dynamic Desmosome Remodeling and Its Impairments in Pemphigus

“…Furthermore, AK23, a pathogenic anti-Dsg3 antibody, activates EGFR, causing an increase in Myc levels, events leading keratinocytes to proliferate in association with Dsg3 depletion and acantholysis in AK23-injected mice (Schulze et al, 2012). Since EGFR activation is associated with keratinocytes wound healing, PV-IgG stimulation may convert keratinocytes into a condition similar to that of wounded keratinocytes.…”

“…PV-IgG-activated signaling molecules found after these fi ndings include EGFR (Bektas et al, 2013;Chernyavsky et al, 2007), Src (Chernyavsky et al, 2007;Cirillo et al, 2014), p38 MAPK (Chernyavsky et al, 2007;Jolly et al, 2010;Spindler et al, 2013), RhoA (Waschke et al, 2006), c-myc (Williamson et al, 2006), PERP (Nguyen et al, 2009), FAK (Gil et al, 2012), Akt/ mTOR (Pretel et al, 2009) and cdk2 (Lanza et al, 2008). Especially, it is worthwhile to note that an anti-Dsg3 antibody, AK23, activates EGFR followed by an increase in Myc levels, events leading keratinocytes to proliferate in association with Dsg3 depletion and acantholysis in AK23-injected mice (Schulze et a., 2012). In addition, PKC involvement in pemphigus appears to be now well accepted in terms of generation of weak-adhesive desmosome condition (Cirillo et al, 2010;Kitajima, 2013;Spindler & Waschke, 2014).…”