LincRNA-ASAO promotes dental pulp repair through interacting with PTBP1 to increase ALPL alternative splicing

Alternative splicing not only expands the genetic encoding of genes but also determines cellular activities. This study aimed to elucidate the regulation mechanism and biological functions of lincRNA-ASAO in the process of odontogenesis-related genes alternative splicing mediated odontogenic differentiation of hDPSCs.

RACE, RNA-seq, FISH and bioinformatics techniques were used to identify novel lincRNA-ASAO. ALP staining, alizarin red staining, qRT-PCR and western blot were used to identify the role of lincRNA-ASAO in regulating the odontoblast differentiation of hDPSCs. The binding protein PTBP1 of lincRNA-ASAO was screened by RNA-Pulldown, protein profiling and bioinformatics. The target gene ALPL of lincRNA-ASAO/PTBP1 was identified by RNA-seq, bioinformatics technology and DNA agarose gel electrophoresis. FISH, IF, PAR-CLIP and bioinformatics techniques were used to determine the roles of lincRNA-ASAO, PTBP1 and ALPL pre-mRNA in the odontoblast differentiation of hDPSCs.

We identified a novel lincRNA-ASAO that could promote the odontogenic differentiation of human Dental Pulp Stem Cells (hDPSCs). And, the interaction between lincRNA-ASAO and alternative splicing factor PTBP1 promoted the odontoblast differentiation of hDPSCs. In addition, lincRNA-ASAO forms duplexes with ALPL pre-mRNA, targeting PTBP1 to exonic splicing silencer (ESS) of ALPL and regulating exon 2 skipping. Notably, lincRNA-ASAO/PTBP1 regulated ALPL production to increase the type 2 splice variant, which promoted the odontoblast differentiation of hDPSCs.

We have identified the novel lincRNA-ASAO, which can promote the odontoblast differentiation of hDPSCs. The mechanism study found that lincRNA-ASAO/PTBP1 mediated the exon 2 skipping of ALPL pre-mRNA, resulting in the type 2 splice variant of ALPL. Our results enrich the understanding of lncRNAs and alternative splicing in regulating the odontoblast differentiation of hDPSCs, and provide clues to improve the clinical therapeutic potential of hDPSCs for dental pulp restoration.