Development of Conformational Antibodies to Detect Bcl-xL's Amyloid Aggregates in Metal-Induced Apoptotic Neuroblastoma Cells

Alexis Gonneaud (1, 2) , Fatima-Zohra Fakhir (1, 3) , Emeline Landas (1) , Enora Le Tallec (1) , Elisabeth Chartier-Garcia (1) , Christine Almunia (4) , Alexandre Chenal (5, 6) , Vincent Forge (1) , Marquette Christel (1)

1 LCBM - UMR 5249 - Laboratoire de Chimie et Biologie des Métaux
2 UdeS - Université de Sherbrooke
3 UCD - Université Chouaib Doukkali
4 LI2D - Laboratoire Innovations technologiques pour la Détection et le Diagnostic
5 Biochimie des Interactions Macromoléculaires / Biochemistry of Macromolecular Interactions
6 Microb. Struc. (UMR_3528 / U-Pasteur_5) - Microbiologie structurale - Structural Microbiology

Bcl-xL, a member of the Bcl-2 family, is a pro-survival protein involved in apoptosis regulation. We have previously reported the ability of Bcl-xL to form various types of fibers, from native to amyloid conformations. Here, we have mimicked the effect of apoptosis-induced caspase activity on Bcl-xL by limited proteolysis using trypsin. We show that cleaved Bcl-xL (Delta N-Bcl-xL) forms fibers that exhibit the features of amyloid structures (BclxLcf37). Moreover, three monoclonal antibodies (mAbs), produced by mouse immunization and directed against Delta N-Bcl-xL or Bcl-xL fibers, were selected and characterized. Our results show that these mAbs specifically target Delta N-Bcl-xL in amyloid fibers in vitro. Upon metal-stress-induced apoptosis, these mAbs are able to detect the presence of Bcl-xL in amyloid aggregates in neuroblastoma SH-SY5Y cell lines. In conclusion, these specific mAbs directed against amyloidogenic conformations of Bcl-xL constitute promising tools for studying, in vitro and in cellulo, the contribution of Bcl-xL in apoptosis. These mAbs may further help in developing new diagnostics and therapies, considering Bcl-xL as a strategic target for treating brain lesions relevant to stroke and neurodegenerative diseases.

Mots clés: Bcl-xL; apoptosis; oxidative stress; amyloid fibers; Bcl-xL

Domaines: Biochimie, Biologie Moléculaire; Biologie cellulaire; Neurosciences [q-bio.NC]

Alexis Gonneaud, Fatima-Zohra Fakhir, Emeline Landas, Enora Le Tallec, Elisabeth Chartier-Garcia, et al.. Development of Conformational Antibodies to Detect Bcl-xL's Amyloid Aggregates in Metal-Induced Apoptotic Neuroblastoma Cells. International Journal of Molecular Sciences, 2020, 21 (20), pp.7625. ⟨10.3390/ijms21207625⟩. ⟨hal-03031819⟩