[Distribution characteristics and proteomic analysis of glioma-associated oncogene homolog 1 positive cells during mouse orthodontic tooth movement].

Abstract

Objective: To explore the distribution characteristics of glioma-associated oncogene homolog 1 (Gli1) positive cells during orthodontic tooth movement process and conduct a proteomic analysis of these cells. Methods: Forty Gli1-LacZ transgenic mice were used to establish an in vivo orthodontic tooth movement (OTM) model for labeling Gli1 positive cells in Gli1-LacZ transgenic mice (OTM group) and an unforced control group, with tooth movement distance measured using micro-CT. The spatial relationship and distribution characteristics of Gli1 positive cells and H-type vessels of CD31 and endomucin (EMCN) in periodontal tissues were detected by immunofluorescence staining. Twenty Gli1-membrane-targeted tandem dimer Tomato (mT)/membrane-targeted green fluorescent protein (mG) double-genotype mice were bred and Gli1 positive cells were sorted for proteomic sequencing after tamoxifen induction. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases were used for enrichment analysis. Results: The micro-CT three-dimensional reconstruction results showed that the mesial movement of the maxillary first molar in mice after 7 days of force application was (69±15) μm, indicating the successful establishment of the Gli1-LacZ transgenic mouse OTM model. Immunofluorescence staining showed that the blood vessels in periodontal tissue were mostly H-type vessels of CD31 and EMCN. The blood vessels in the periodontal tissues are predominantly H-type vessels positive for both CD31 and EMCN. The percentage of Gli1 positive cells in the OTM group, expressed as (54.5±13.2)%, and the relative fluorescence intensity, expressed as 2.6±0.9, were both significantly greater than those in the control group, which had a Gli1 positive cell percentage of (36.3±9.1)% (t=3.60, P=0.002) and a relative fluorescence intensity of 1.0±0.3 (t=5.20, P<0.001). In contrast to the control group where only a small number of Gli1 positive cells were consistent with the distribution of H-type vessels, in the OTM group the number of Gli1 positive cells increased on the tension side were closely associated with the spatial distribution of H-type vessels. GO enrichment analysis of biological processes found that a large number of proteins in Gli1 positive cells were enriched in pathways such as angiogenesis and tissue remodeling. KEGG enrichment analysis found that related proteins were mainly enriched in pathways related to angiogenesis and Gli1, such as hypoxia-inducing factor 1 signaling pathway, vascular endothelial growth factor signaling pathway and hedgehog signaling pathway. Conclusions: The number of Gli1 positive cells increased on tension side and were closely related to H-type blood vessels in response to mechanical force during orthodontic tooth movement. This may be related to profile of inducing blood vessel formation and tissue remodeling.