Loss of function mutation in progressive ankylosis (Ank) gene causes aberrant mineralization and acquisition of osteoblast-like-phenotype by annulus fibrosus cells in the intervertebral disc

Transcriptomic analysis of nucleus pulposus (NP) and annulus fibrosus (AF) tissues from intervertebral discs of 3-month-old mice with loss of function mutation of Ank gene. Regulator of extracellular inorganic pyrophosphate, Ank is essential for preventing ectopic mineralization in the extracellular matrices, maintaining the health of the intervertebral disc of mice. We examined the transcriptomic profiles of nucleus pulposus and annulus fibrosus cells in control and Ank mutant mice using microarrays. Tissues from the nucleus pulposus (NP) and annulus fibrosus (AF) were harvested from the intervertebral discs of five wild-type (WT) and five Ank mutant mice (ank/ank) of 13-week-old of age. NP and AF tissues were separately pooled from lumbar and caudal discs in each animal for RNA extraction and hybridization using Affymetrix microarrays.