Sulfur Mustard Disrupts Human Alpha(3)Beta(4)-Integrin Receptors in Concert With Alpha(6)Beta(4)-Integrin Receptors and Collapse of the Keratin K5/K14 Cytoskeleton

Sulfur mustard (SM; bis(2-chloroethyl) sulfide) is a chemical warfare agent that produces persistent, incapacitating blisters of the skin. The lesions inducing vesication remain elusive, and there is no completely effective treatment. Using multiphoton microscopy and immunofluorescent staining, we found that exposing human epidermal keratinocytes (HEK) and intact epidermis to SM (400 muM for 5 min) caused progressive collapse of the keratin (K5/K14) cytoskeleton and depletion of alpha6beta4 integrins.1 We now report that SM causes concomitant disruption and collapse of the basal cell's alpha3beta1-integrin receptors. At 1 h postexposure, images of Alexa488-conjugated HEK/alpha3beta1 integrins showed almost complete withdrawal and disappearance of retraction fibers and a progressive loss of polarized mobility. With stereo imaging, in vitro expression of this SM effect was characterized by collapse and abutment of adjacent cell membranes. At 2 h postexposure, there was an average 13% dorso-ventral collapse of HEK membranes that paralleled progressive collapse of the K5/K14 cytoskeleton. Alpha3beta1 integrin, like alpha6beta4 integrin, is a regulator of cytoskeletal assembly, a receptor for laminin 5 and a mediator of HEK attachment to the basement membrane. Our images indicate that SM disrupts these receptors. We suggest that the progressive disruption destabilizes and potentiates blistering of the epidermal-dermal junction. The original document contains color images. Pub. in Jnl. of Multiphoton Microscopy in the Biomedical Sciences IV (eds. A. /Periasamy and P.T.C. So), Proceedings of SPIE, v5323 p297-305, 2004, Society of Photo-Optical Instrumentation Engineers: Bellingham, WA.