摘要：The cellular and molecular mechanisms underlying spinal deformity progression in adolescent idiopathic scoliosis (AIS) remain poorly understood. In this study, 804 French-Canadian patients and 278 age- and sex-matched controls were enrolled and genotyped for 12 single nucleotide polymorphisms (SNPs) in the chitinase 3-like 1 (CHI3L1) gene or its promoter. The plasma YKL-40 levels were determined by ELISA. We showed that elevation of circulating YKL-40 levels was correlated with a reduction of spinal deformity progression risk. We further identified significant associations of multiple CHI3L1 SNPs and their haplotypes with plasma YKL-40 levels and scoliosis severity as a function of their classification in a specific endophenotype. In the endophenotype FG3 group, we found that patients harboring the haplotype G-G-A-G-G-A (rs880633 rs1538372 rs4950881 rs10399805 rs6691378 rs946261), which presented in 48% of the cases, showed a positive correlation with the plasma YKL-40 levels (P = 7.6 × 10−6 and coefficient = 36). Conversely, the haplotype A-A-G-G-G-G, which presented in 15% of the analyzed subjects, showed a strong negative association with the plasma YKL-40 levels (P = 2 × 10−9 and coefficient = −9.56). We found that this haplotype showed the strongest association with AIS patients in endophenotype FG2 (P = 9.9 × 10−6 and coefficient = −13.53), who more often develop severe scoliosis compared to those classified in the other two endophenotypes. Of note, it showed stronger association in females (P = 1.6 × 10−7 and coefficient = −10.08) than males (P = 0.0021 and coefficient = −9.01). At the functional level, we showed that YKL-40 treatments rescued Gi-coupled receptor signalling dysfunction occurring in primary AIS osteoblasts. Collectively, our findings reveal a novel role for YKL-40 in AIS pathogenesis and a new molecular mechanism interfering with spinal deformity progression.
