Cells expressing partially unfolded R789C/p.R989C type II procollagen mutant associated with spondyloepiphyseal dysplasia undergo apoptosis

• DOI: 10.1002/humu.20736
• Publication Date: 2008-03-27T16:17:13Z
• Authors: Vera Hintze; Andrzej Steplewski; Hidetoshi Ito; Deborah A. Jensen; Ulrich Rodeck; Andrzej Fertala
• Keywords: Mice; 0303 health sciences; 03 medical and health sciences; Chondrocytes; Amino Acid Substitution; Green Fluorescent Proteins; Mutation, Missense; Animals; Apoptosis; Collagen Type XI; Osteochondrodysplasias; Collagen Type II

We investigated the effects of presence R75C (p.R275C), R519C (p.719C), R789C (p.R989C), and G853E (p.G1053E) type II collagen (COL2A1) mutants, associated with distinct forms spondyloepiphyseal dysplasia (SED), on biological processes occurring in chondrocytic cells harboring those mutants. Mutant-specific responses were initiated by activating tetracycline (Tet)-dependent expression Employing microscopic biochemical assays, we determined that expressing thermolabile (p.R989C) mutant undergo apoptosis. In contrast, thermostable apoptotic markers not apparent. also demonstrated formed atypical complexes endoplasmic reticulum (ER)-resident chaperones, thereby indicating an "unfolded protein response" (UPR) this specific mutant. Apoptotic changes terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) cleaved caspase 3 assays growth plates mice R992C (p.R1147C) substitution collagen. Based these results, propose intracellular structurally altered mutants could activate response, limiting cell survival. By analyzing response to structure our study contributes better understanding molecular basis pathological seen vivo at tissue level.