Core planar cell polarity genes VANGL1 and VANGL2 in predisposition to congenital vertebral malformations.

Congenital scoliosis (CS), affecting approximately 0.5 to 1 in 1,000 live births, is commonly caused by congenital vertebral malformations (CVMs) arising from aberrant somitogenesis or somite differentiation. While Wnt/ß-catenin signaling has been implicated in somite development, the function of Wnt/planar cell polarity (Wnt/PCP) signaling in this process remains unclear. Here, we investigated the role of Vangl1 and Vangl2 in vertebral development and found that their deletion causes vertebral anomalies resembling human CVMs. Analysis of exome sequencing data from multiethnic CS patients revealed a number of rare and deleterious variants in VANGL1 and VANGL2, many of which exhibited loss-of-function and dominant-negative effects. Zebrafish models confirmed the pathogenicity of these variants. Furthermore, we found that Vangl1 knock-in (p.R258H) mice exhibited vertebral malformations in a Vangl gene dose- and environment-dependent manner. Our findings highlight critical roles for PCP signaling in vertebral development and predisposition to CVMs in CS patients, providing insights into the molecular mechanisms underlying this disorder.

Selection and characterization of DNA aptamers inhibiting a druggable target of osteoarthritis, ADAMTS-5.

There is a critical need for the development of more potent inhibitors for osteoarthritis (OA) therapy given the poor life quality of arthritis patients. Aggrecanase ADAMTS-5 (a disintegrin and metalloproteinase with thrombospondin motifs 5) is an established drug target identified for osteoarthritis. In this study, we evolved and characterized two new DNA aptamer inhibitors of ADAMTS-5, namely apt21 and apt25. The aptamers exhibited nanomolar binding affinity and high specificity against ADAMTS-5. KD values of apt21 and apt25 were determined by the Enzyme-linked Oligonucleotide Assay (ELONA) at 1.54 ± 0.16 nM and 1.79 ± 0.08 nM, respectively. Circular Dichroism (CD) analysis demonstrated that both aptamers formed monovalent cation dependent G-quadruplex structures. Calcium ions did not affect the binding of the aptamers to ADAMTS-5. The inhibitory effects of apt21 and apt25 on ADAMTS-5 were evaluated by the Förster Resonance Energy Transfer (FRET) assay, in which IC50 values of apt21 and apt25 were estimated at 52.76 ± 6.70 µM and 61.14 ± 9.67 µM, respectively. These two aptamers are the first DNA G-quadruplex aptamers demonstrated to inhibit ADAMTS-5 and could have value for OA therapy.

Identification of Copy Number Variants in a Southern Chinese Cohort of Patients with Congenital Scoliosis.

Congenital scoliosis (CS) is a lateral curvature of the spine resulting from congenital vertebral malformations (CVMs) and affects 0.5-1/1000 live births. The copy number variant (CNV) at chromosome 16p11.2 has been implicated in CVMs and recent studies identified a compound heterozygosity of 16p11.2 microdeletion and TBX6 variant/haplotype causing CS in multiple cohorts, which explains about 5-10% of the affected cases. Here, we studied the genetic etiology of CS by analyzing CNVs in a cohort of 67 patients with congenital hemivertebrae and 125 family controls. We employed both candidate gene and family-based approaches to filter CNVs called from whole exome sequencing data. This identified 12 CNVs in four scoliosis-associated genes (TBX6, NOTCH2, DSCAM, and SNTG1) as well as eight recessive and 64 novel rare CNVs in 15 additional genes. Some candidates, such as DHX40, NBPF20, RASA2, and MYSM1, have been found to be associated with syndromes with scoliosis or implicated in bone/spine development. In particular, the MYSM1 mutant mouse showed spinal deformities. Our findings suggest that, in addition to the 16p11.2 microdeletion, other CNVs are potentially important in predisposing to CS.

Genetic variants of TBX6 and TBXT identified in patients with congenital scoliosis in Southern China.

Congenital scoliosis (CS) is a spinal deformity present at birth due to underlying congenital vertebral malformation (CVM) that occurs during embryonic development. Hemivertebrae is the most common anomaly that causes CS. Recently, compound heterozygosity in TBX6 has been identified in Northern Chinese, Japanese, and European CS patient cohorts, which explains about 7%-10% of the affected population. In this report, we recruited 67 CS patients characterized with hemivertebrae in the Southern Chinese population and investigated the TBX6 variant and risk haplotype. We found that two patients with hemivertebrae in the thoracic spine and one patient with hemivertebrae in the lumbar spine carry the previously defined pathogenic TBX6 compound heterozygous variants. In addition, whole exome sequencing of patients with CS and their family members identified a de novo missense mutation (c.G47T: p.R16L) in another member of the T-box family, TBXT. This rare mutation compromised the binding of TBXT to its target sequence, leading to reduced transcriptional activity, and exhibited dominant-negative effect on wild-type TBXT. Our findings further highlight the importance of T-box family genes in the development of congenital scoliosis.