Gli1 creert2

Male C57BL/6J mice, 1 month of age, were obtained from Chengdu Dossy Experimental Animals Co., Ltd. (Chengdu, China). To establish a glucocorticoid-induced model of osteopenia, MPS (25 mg/kg/day) or vehicle was administered by daily intraperitoneal injection to 1-month-old male C57BL/6J mice for 4 weeks. The genotype of Gli1-CreER^T2; tdTomato mice was obtained by crossing the Gli1-CreER^T2 (Jackson lab (Bar Harbor, ME, USA), strain #007913) mice with the tdTomato (Jackson lab, strain #007909) mice. The Gli1-CreER^T2; tdTomato mice were administrated Tamoxifen (TAM) (APExBIO (Houston, TX, USA)) intragastrically at the age of one month for three consecutive days. The dose of the TAM was used as 2 mg/30 g body weight. After TAM administration, Gli1-CreER^T2; tdTomato mice were injected with MPS or vehicle daily for 5 days. The 5-ethynyl-2′-deoxyuridine (EdU) was dosed at 2 mg/g body weight and injected 4 h before harvest. For the rescue experiments, the dosage of Teriparatide was 0.4 mg per gram of body weight. All the mice were kept in a specific pathogen-free facility at Sichuan University with a 12 h light and 12 h dark cycle in a temperature-regulated room with a standard chow diet. All mice experiments were approved by the Institution Animal Care and Use Committee (IACUC) of Sichuan University of West China Hospital (No. 20220411002).

Mice carrying the floxed Sufu allele (Sufu^fl, ‘RRID:MGI:4840420’) were kindly provided by Dr. Chi-Chung Hui (University of Toronto) and were genotyped as described elsewhere (Pospisilik et al., 2010 (link)). The following mouse lines were obtained from Jackson Laboratory (Bar Harbor, Maine): Gli1^CreERT2/+ (stock #007913, ‘RRID:MGI:3053957’), Gli1^LacZ/+ (Stock #008211, ‘RRID:MGI:J:79392’), Rosa-AI14 (Stock #007908, ‘RRID:MGI:J:155793’), SmoM2 (Stock #005130, ‘RRID:MGI:3576373’), hGFAP-Cre (Stock #004600, ‘RRID:MGI:2179048’). Both male and female mice were analyzed with no distinction. All mice used in this study were maintained on a 12 hr light/dark cycle with free access to food and water. The day of vaginal plug was considered embryonic day 0.5. Mouse colonies were maintained at University of California San Francisco (UCSF) in accordance with National Institutes of Health and UCSF guidelines.

C57BL/6J mice were purchased from Charles River Laboratories (Jiaxing, China) and Shanghai SLAC Laboratory Animal Co.Ltd (Shanghai, China). Gli1^CreERT2, Lgr5^{EGFP−CreERT2}, R26R^tdTomato mice were purchased from the Jackson Laboratory. Gli1^CreERT2; R26R^tdTomato and Lgr5^{EGFP−CreERT2}; R26R^tdTomato mice were used to monitor the activation and proliferation of Gli1+ and Lgr5+ HFSCs after treatment. Four or six days after depilation, mice (6–7 weeks old) received three i.p. injections of 200 mg/kg Tamoxifen (MACKLIN, Shanghai, China) dissolved in corn oil (MACKLIN) at 1-day intervals. Mice were housed with a 12 h/12 h light/dark cycle at 22 °C, with free access to food and water. Only male mice were used for the experiments. The experimental study was conducted according to the institutional guidelines with approval from the Review Committee of Zhejiang Chinese Medical University.

Mice were purchased from the Jackson Lab with genotypes including C57BL/6 (JAX # 000664), Thy1-EGFP-M (JAX# 007788), Thy1-YFP-16 (JAX #003709), Ai14 (JAX# 007908), Ai 140 (JAX# 030220), Shh-Cre^ERT2 (JAX# 005623) and Gli1-cre^ERT2 (JAX# 007913). All animal experiments were approved by the Institutional Animal Care and Use Committee of the Chinese Institute for Brain Research.
For tamoxifen treatment, tamoxifen (Sigma-Aldrich, T5648) was dissolved in corn oil (Sigma-Aldrich, C8267) at 20 mg/mL. The solution was kept at –20 °C and delivered via intraperitoneal injection or oral gavage for postnatal treatments.

Actin-CreER^T2, αSMA-CreER^T2, PDGFRα-CreER^T2, and Gli1-CreER^T2 mouse strains were obtained from Jackson Laboratories, Rosa26-VT2/GK3 Rainbow mice were provided as a gift from the Weissman Laboratory, Stanford University School of Medicine. All animal procedures were carried out under the guidance of the Stanford University Administrative Panel on Laboratory Animal Care (APLAC).
Prior to induction, mTmG (Actin-CreER^T2::Rosa26-mTmG, αSMA-CreER^T2::Rosa26-mTmG, Gli1-CreER^T2::Rosa26-mTmG, and PDGFRα-CreER^T2::Rosa26-mTmG) and Rainbow mice (Actin-CreER^T2::Rosa26-VT2/GK3) were assessed for Cre leakiness in multiple tissue types including skin, bone, and large intestine.

The following mouse strains were obtained from the Jackson Laboratory: Gli1‐LacZ (JAX# 008211), ROSA26‐eGFP‐DTA (JAX# 006331), Gli1‐CreER^T2 (JAX# 007913) and Yap^flox (JAX# 027929). All mice were housed in a pathogen‐free condition, maintained on the standard 12‐hour light‐dark cycle. Offspring were genotyped by PCR according to the primer sequences provided by the Jackson Laboratory, and mice were used for experiments regardless of sex at the age of 10‐12 weeks. All animal experiments were performed following the guidelines of the Intramural Animal Use and Care Committee of the Fourth Military Medical University (license number: 2018‐kq‐014).