BACH1 Binding Links the Genetic Risk for Severe Periodontitis with ST8SIA1

Abstract

Genome-wide association studies identified various loci associated with periodontal diseases, but assigning causal alleles remains difficult. Likewise, the generation of biological meaning underlying a statistical association has been challenging. Here, we characterized the genetic association at the gene ST8SIA1 that increases the risk for severe periodontitis in smokers. We used CRISPR/dCas9 activation and RNA-sequencing to identify genetic interaction partners of ST8SIA1 and to determine its function in the cell. We used reporter gene assays to identify regulatory elements at the associated single-nucleotide polymorphisms (SNPs) and to determine effect directions and allele-specific changes of enhancer activity. Antibody electrophoretic mobility shift assays proved allele-specific transcription factor binding at the putative causal SNPs. We found the reported periodontitis risk gene ABCA1 as the top upregulated gene following ST8SIA1 activation. Gene set enrichment analysis showed highest effects on integrin cell surface interactions (area under the curve [AUC] = 0.85; q = 4.9 × 10−6) and cell cycle regulation (AUC = 0.89; q = 1.6 × 10−5). We identified 2 associated repressor elements in the introns of ST8SIA1 that bind the transcriptional repressor BACH1. The putative causative variant rs2012722 decreased BACH1 binding by 40%. We also pinpointed ST8SIA1 as the target gene of the association. ST8SIA1 inhibits cell adhesion with extracellular matrix proteins, integrins, and cell cycle, as well as enhances apoptosis. Likewise, tobacco smoke reportedly results in an inhibition of cell adhesion and a decrease in integrin-positive cells and cell growth. We conclude that impaired ST8SIA1 repression, independently caused by reduced BACH1 binding at the effect T allele, as well as by tobacco smoke, contributes to higher ST8SIA1 levels, and in smokers who carry the effect T allele, both factors would be additive with damaging effects on the gingival barrier integrity. The activity of ST8SIA1 is also linked with the periodontitis risk gene ABCA1.

Knockdown of Bach1 protects periodontal bone regeneration from inflammatory damage

“…It has also been reported that drugs and biomaterials such as hyperoside, gold nanoparticles and sodium arsenite could elicit Bach1 nuclear export and increase the expression of antioxidative enzymes 37–39 . At the genetic level, it has been reported that the elevated expression of ST8SIA1, a periodontitis risk gene, caused by weakening of Bach1's binding to effect T allele of its coinherited variants is a genetic cause of periodontitis 40 . Further studies will be necessary to verify the role of these drugs in the treatment of periodontitis and the promotion of periodontal tissue regeneration.…”

“…ST8SIA1, a periodontitis risk gene, caused by weakening of Bach1's binding to effect T allele of its coinherited variants is a genetic cause of periodontitis. 40…”

Case‐only design identifies interactions of genetic risk variants at SIGLEC5 and PLG with the lncRNA CTD‐2353F22.1 implying the importance of periodontal wound healing for disease aetiology

“…These methods were performed as recently described (Chopra et al, 2021) and we give all experimental details in Appendix.…”

lncRNA CDKN2B-AS1 regulates collagen expression

“…In brief, pGFs cells and immortalized Human Gingival Fibroblast cells (iHGF) (ABM, Canada) were grown in Dulbecco's modi ed Eagle's medium (DMEM, PAN Biotech, Germany) supplemented with 10% fetal bovine serum (FBS, Gibco, USA), and 1% non-essential amino acids (MEM-NEAA, PAN Biotech). HeLa cells were cultured as recently described (Chopra et al 2021). Brie y, cells were cultured in Earle's MEM (Bio&Sell, Nuremberg, Germany) supplemented with 10% FBS, 2mM L-Glutamine (Bio&Sell), and 1%NEAA.…”

“…To characterize allele-speci c DNA-protein interaction and TF STAT1 binding at rs10757278, we performed EMSAs with the Gelshift Chemiluminescent EMSA Kit (Active Motif, Germany) as recently described (Chopra et al 2021). In brief, allele-speci c oligonucleotide probes were synthesized (Metabiom International, Supplementary Materials Table S2).…”