library_construction_protocol: In brief, after rinsing with 1% PBS for three times, the adventitia were cut and digested with an enzyme digestion [2mg/mL collagenase type Ⅰ (Invitrogen; 17018-029), 2 mg/ml disapase Ⅱ（Sigma; C2-BIOC） in Hank's balance salt solution containg calcium and magesium] for 2h at 37℃. The cell suspension was strained through a 70 μm filter, washed twice in the 1×PBS and then resuspended at 1×106 cells per ml in 1×PBS and 0.04% bovine serum albumin, then subjected to scRNA-seq. The scRNA-seq was conducted using the Standard 10x Chromium Single Cell 3′ v3 protocol by 10X Genomics GemCode Technology. In summary, single cells were individually tagged with a unique 10x Barcode and unique molecular identifier through the encapsulation into Gel Bead-In-Emulsions. Sequences sharing identical 10x Barcodes were then classified as originating from the same cell. The resultant cDNA library was prepared and subjected to sequencing on the Nova PE150 platform.