Sera of patients with celiac disease and neurologic disorders evoke a mitochondrial-dependent apoptosis in vitro.
OBJECTIVE
The mechanisms underlying neurologic impairment in celiac disease remain unknown. We tested whether antineuronal antibody-positive sera of patients with celiac disease evoke neurodegeneration via apoptosis in vitro.


METHODS
SH-Sy5Y cells were exposed to crude sera, isolated immunoglobulin (Ig) G and IgG-depleted sera of patients with and without celiac disease with and without neurologic disorders, and antineuronal antibodies. Adsorption studies with gliadin and tissue transglutaminase (tTG) were performed in celiac disease sera. Apoptosis activated caspase-3, apaf-1, Bax, cytochrome c, cleaved caspase-8 and caspase-9 and mitochondrial respiratory chain complexes were evaluated with different methods.


RESULTS
SH-Sy5Y cells exposed to antineuronal antibody-positive sera and isolated IgG from the same sera exhibited a greater percentage of TUNEL-positive nuclei than that of antineuronal antibody-negative sera. Neuroblasts exposed to antineuronal antibody-negative celiac disease sera also showed greater TUNEL positivity and apaf-1 immunolabeled cells than controls. Antigliadin- and anti-tTG-depleted celiac disease sera had an apoptotic effect similar to controls. Anti-caspase-3 immunostained cells were greater than controls when exposed to positive sera. The mitochondrial respiratory chain complex was reduced by positive sera. Western blot demonstrated only caspase-9 cleavage in positive sera. Cytochrome c and Bax showed reciprocal translocation (from mitochondria to cytoplasm and vice versa) after treatment with positive sera.


CONCLUSIONS
Antineuronal antibodies and, to a lower extent, combined antigliadin and anti-tTG antibodies in celiac disease sera contribute to neurologic impairment via apoptosis. Apaf-1 activation with Bax and cytochrome c translocation suggest a mitochondrial-dependent apoptosis.
Cervio
Elisabetta
E
Department of Physiological & Pharmacological Sciences, University of Pavia, Pavia, Italy.
Volta
Umberto
U
Verri
Manuela
M
Boschi
Federica
F
Pastoris
Ornella
O
Granito
Alessandro
A
Barbara
Giovanni
G
Parisi
Claudia
C
Felicani
Cristina
C
Tonini
Marcello
M
De Giorgio
Roberto
R
D000328:Adult; D017209:Apoptosis / Q000276:immunology*; D053477:Apoptotic Protease-Activating Factor 1 / Q000378:metabolism; D006690:Bisbenzimidazole; D053148:Caspase 3 / Q000378:metabolism; D053453:Caspase 9 / Q000378:metabolism; D002446:Celiac Disease / Q000097:blood / Q000276:immunology* / Q000473:pathology*; D045744:Cell Line, Tumor; D002950:Citrate (si)-Synthase / Q000378:metabolism; D045304:Cytochromes c / Q000378:metabolism; D042967:Electron Transport Complex I / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005456:Fluorescent Dyes; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood* / Q000494:pharmacology; D020287:In Situ Nick-End Labeling; D066298:In Vitro Techniques; D008297:Male; D008875:Middle Aged; D008928:Mitochondria / Q000378:metabolism*; D009410:Nerve Degeneration / Q000276:immunology* / Q000473:pathology; D009447:Neuroblastoma; D051028:bcl-2-Associated X Protein / Q000378:metabolism
C506592:APAF1 protein, human; D053477:Apoptotic Protease-Activating Factor 1; C494826:BAX protein, human; D005456:Fluorescent Dyes; D007074:Immunoglobulin G; D051028:bcl-2-Associated X Protein; D045304:Cytochromes c; D002950:Citrate (si)-Synthase; D053148:Caspase 3; D053453:Caspase 9; D042967:Electron Transport Complex I; D006690:Bisbenzimidazole