Identification of ER α gene polymorphism in adolescent idiopathic scoliosis (AIS)

1. Identification of ERα gene polymorphism in adolescent idiopathic scoliosis (AIS) L.-O. Lévesque, A. Moreau, PhD S. Leclerc, PhD, H. Labelle, MD, G. Grimard, MD, F. Moldovan, PhD.

2. What is adolescent idiopathic scoliosis ? • 80% of scoliosis are idiopathic (without cause) • Affects 2-3% of adolescents in Quebec • Only 0,2% have a cobb angle over 40°

3. Do estrogens contribute to AIS? • AIS affects mainly girls • AIS appears at the same time that estrogens rise in young girls blood. • Scoliosis progression can be predicted by bone age, menarche and pubertal stage, all of which are related to the presence of estrogens • Environmental factors: phytoestrogens (nutrition)

4. Known receptors of estrogens • There are 2 types of known receptors to the estrogens: ERα and ERβ • Both are nuclear receptors of the steroids receptors super-family • The ligand–receptor complex binds to ERE and AP-1 promoter sequence • New evidences for a non-nuclear rapid action of the Estrogens • The role of ERα and ERβ remains to be ascertained

5. Methodology • All these experiments were done on human tissues or cell lines of human origin. • MG-63, Control tissues and Scoliotic tissues all of which have been collected according to Sainte-Justine hospital’s ethic protocol • By RT-PCR, we have seek ERα and ERβ in different human cell lines and scoliotic cell lines • We have performed digestion by restriction enzymes on PCR amplicon to ascertain the presence of polymorphisms associated with ERα.

6. No enzymes PvuII XbaI RFLPolymorphism Allele A Allele B Amplicons Digestion enzyme enzyme Digested fragments

7. Results

8. chondrcytes MG-63 Patient A Patient B GAPDH GAPDH GAPDH GAPDH ERα ERα ERβ ERβ ERα ERα ERβ ERβ Expression of ERα and ERβ in human cells and scoliotic tissues by RT-PCR

9. Relevance of this RFLP study • Statistically related to curve progression in Japanese population (right thoracic) (Inoue et al. 1996) • These RFLP are located in an intron • Will not be expressed in the a.a. sequence • May affect transcription factors binding • RFX1 for example which also binds to growth factors promoters • May affect the splicing • Alternative splicing… • Ex.: 66kDa and 46kDa

10. Conclusion & Perspectives • A lot is left to investigate… • ERα and ERβ was detected in osteoblasts but… • What modulates them remains to be ascertain • The full impact of those receptors on the scoliotic bone is still unclear • The nuclear action of Estrogens has been well studied but there are evidence of non-nuclear action that should be investigated • Detected the polymorphism in our population. • Only on a small scale • Correlate the presence of the polymorphism and ERα levels