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The caspase inhibitor Ac‐DEVD‐CMK decreases the availability Ro antigen triggered by apoptosis
Author(s) -
HerreraEsparza Rafael,
VillalobosHurtado Ricardo,
BollainyGoytia JuanJose,
PachecoTovar MariaGuadalupe,
LopezRobles Erendira,
AvalosDiaz Esperanza
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.5.a1102-a
Subject(s) - apoptosis , tunel assay , antigen , microbiology and biotechnology , monoclonal antibody , uvb induced apoptosis , polyclonal antibodies , antibody , chemistry , caspase 8 , dna fragmentation , immunology , caspase , cancer research , biology , programmed cell death , biochemistry
Mechanisms that trigger autoantibody production still partially known; such phenomenon seems to be linked to autoantigen availability. It has been recognized that the epidermal apoptotic cells constitute a major source of autoantigens; especially those linked to the photosensitive subacute cutaneous lupus erythematosus (SCLE) that produce anti‐Ro antibodies. Our major goal was to demonstrate whether UV light induces apoptosis and increase the availability of Ro autoantigen. Also the blocking effect of a caspase inhibitor was assessed. For this purpose newborn Balb/c mice (n= 6/group), were UVB irradiated (5–30 mJ/cm 2 ) equivalent to a moderate to severe sunburn. Irradiated and non‐irradiated animals were injected with monoclonal anti‐Ro antibodies or with a polyclonal anti‐Ro from a SCLE patient, or with normal IgG. In other group the apoptosis was induced with an anti‐Fas monoclonal antibody. Some animals were treated with the caspase inhibitor Ac‐DEVD‐CMK. The skin was examined by direct immunofluorescence, by TUNEL. The epidermis was obtained by splitting the skin with dispase, epidermal DNA and RNA were isolated by TRIsol followed by RT‐PCR for caspase 3, Fas, FasL, Bax, and DFF40. Major findings of present studies were: 1. UVB irradiation induces apoptosis of keratinocytes. 2. UVB and anti‐Fas induced apoptosis and redistribution of the Ro antigen on cell surface. 3. Apoptotic keratinocytes are better triggered by the monoclonal or polyclonal anti‐Ro antibodies. 4. The blocking effect of Ac‐DEVD‐CMK on caspases decreases the Ro autoantigen availability and the anti‐Ro antibody deposition. Finally the caspase pathway would be blocked to prevent the cutaneous lupus flare ups of SCLE.