Superficial Dsg2 Expression Limits Epidermal Blister Formation Mediated by Pemphigus Foliaceus Antibodies and Exfoliative Toxins
Figure 2
Superficial expression of Dsg2 offers protection from ETA-induced blister formation. (a) Newborn WT and Inv-Dsg2 Tg mice were injected subcutaneously with 0.5 g ETA in PBS. Visible blisters were observed in WT but not Tg mice, 6–8 hours after ETA treatment. (b) Mice were sacrificed, and their skin was processed for histological analysis, revealing slightly more extensive blisters in the WT mice (), as compared to Tg mice (), in response to ETA. Top panels show 3X magnification, and lower panels show 40X magnification of the site of blister formation. (c) The extent of blistering was graded based on the following semiquantitative scale: 0: no blisters, 1+: minor blisters at the edge; 2+: localized blisters 50%; 3+: extensive blisters 50%; and 4+: very extensive blisters 75%. Each dot represents one mouse. The average blister scores were 2.6 ± 1.2 for WT and 1.7 ± 1.3 for Tg. These values were statistically significant, ≤ .038260921 (2-tailed unequal variance) or ≤ .01913046 (1-tailed unequal variance). (d) The back skin biopsies were homogenized in Laemmli buffer, proteins were resolved with SDS-PAGE and immunoblotted for Dsg1 (27B2), Dsg2-Flag (Flag), and Actin (for equal loading). Western blotting demonstrates that ETA cleaved Dsg1 (arrowhead), but not Dsg2. Note. antibody 27B2 was raised against the cytoplasmic epitope of human Dsg1, and recognizes mouse Dsg1-, -, and -. Thus, the full-length signal is most likely ETA-resistant Dsg1-.
