library_construction_protocol: Under dissection microscope, the gingival tissue attached to the alveolar supporting all the three maxillary molars was incised  and peeled off. The excised gingival tissue was transferred to a culture dish containing 1ml PBS with 10%FBS, 2mg/ml Collagenase Type II, 1mg/ml DNAse Type I and 5mM EDTA , miced thoroughly with a No.15 blade and incubated in a shaker incubator for 20 minutes at 37℃ and 200rpm. After digestion, the cells were centrifuged at 400X for 10 minutes, resuspend in 1ml PBS+10%FBS and filtered through a 70um strainer. Each cell sample was collected from three male and three female animals. The strained single cells were stained for Ter119-FITC , CD45-FITC and CD31-FITC for 30 minutes on ice. Dead cells were labelled with 7-AAD. Ter119-CD45-CD31- live cells were collected using the FACSAria II sorter. Sorted gingival cells were adjusted to 800-1200/ul for scRNA-seq library preparation. Libraries were constructed using Chromium Single Cell 3' v2 Reagent Kit as instructed by the manufacturer's manual