Neurogenic chronic intestinal pseudo-obstruction: antineuronal antibody-mediated activation of autophagy via Fas.
OBJECTIVE
Activation of autoimmune pathways has been implicated as a contributing mechanism to the pathophysiology in some patients with chronic intestinal pseudoobstruction (CIP). In this study we tested the hypothesis that sera from a subpopulation of patients with CIP contain autoantibodies that activate autophagy via a Fas-dependent pathway in cultured human neuroblastoma SH-Sy5Y cells.


METHODS
Twenty-five patients with established neurogenic CIP (20 women, 5 men; age range, 21-57 y) were investigated and circulating antineuronal antibodies to enteric neurons were found in 6 (24%) patients. The ability of antineuronal antibodies to induce autophagy was assessed using immunohistochemical, Western immunoblot, and molecular techniques. The presence of autophagosomes was monitored using a specific immunohistochemical marker, anti-microtubule-associated light chain immunoreactivity, and colocalization with mitochondrial- and Fas-activated death domain immunofluorescence using appropriate antibodies in cells exposed to sera from matched healthy controls and patients with neurogenic CIP.


RESULTS
Exposure of SH-Sy5Y cells to sera from patients with CIP containing antineuronal antibodies revealed increased binding of autoimmune immunoglobulin (IgG class) to the surface of SH-Sy5Y cells and increased formation of autophagosomes showing colocalization with mitochondria and Fas-activated death domain compared with control sera. Pretreatment of sera with either protein L agarose beads or a soluble Fas receptor (extracellular domain) chimera prevented the stimulation of autophagy.


CONCLUSIONS
We provide novel evidence that antineuronal antibodies may contribute to neuronal dysfunction observed in a subset of patients with neurogenic CIP via autoantibody-mediated activation of autophagy involving the Fas receptor complex.
de Giorgio
Roberto
R
Department of Internal Medicine and Gastroenterology, Centro Unificato di Ricerca BioMedica Applicata, University of Bologna, Bologna, Italy.
Volta
Umberto
U
Stanghellini
Vincenzo
V
Cogliandro
Rosanna F
RF
Barbara
Giovanni
G
Corinaldesi
Roberto
R
Towns
Roberto
R
Guo
Chunfang
C
Hong
Shuangsong
S
Wiley
John W
JW
D000328:Adult; D000917:Antibody Formation; D001323:Autoantibodies / Q000097:blood*; D001343:Autophagy; D015153:Blotting, Western; D016022:Case-Control Studies; D045744:Cell Line, Tumor; D002908:Chronic Disease; D017615:Enteric Nervous System / Q000276:immunology* / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D053200:Fas-Associated Death Domain Protein / Q000378:metabolism; D005260:Female; D006801:Humans; D007136:Immunoglobulins / Q000378:metabolism; D007150:Immunohistochemistry; D007418:Intestinal Pseudo-Obstruction / Q000276:immunology* / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D008297:Male; D008365:Manometry; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D008875:Middle Aged; D008928:Mitochondria / Q000276:immunology; D009419:Nerve Tissue Proteins / Q000276:immunology*; D009474:Neurons / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D019014:fas Receptor / Q000378:metabolism*
D001323:Autoantibodies; D053200:Fas-Associated Death Domain Protein; D007136:Immunoglobulins; C477012:MAP1LC3A protein, human; D008869:Microtubule-Associated Proteins; D009419:Nerve Tissue Proteins; D019014:fas Receptor