Wt mice

WT animals as well as Tbx21^−/− and Ffar2^−/−Ffar3^−/−mice (all mouse strains were on C57BL/6 background) were housed in specific pathogen free (SPF) conditions at the animal facility of the Philipps-University of Marburg, Germany. WT mice were obtained from Charles River Laboratories. Ffar2^−/−Ffar3^−/− mice were generously provided by Dr. Stefan Offermanns (Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany). All animal procedures were carried out according to the German animal protection law. Experiments were done after approval by Regierungspräsidium Gießen, Germany (animal experimentation application EX7-2015). In some experiments, WT mice were orally treated with 150 mM sodium butyrate for four weeks as described previously^{8 (link)}. Water solutions containing butyrate were pH-matched and changed weekly.

Age-matched (12–16 weeks) female Ldlr^−/− mice on a C57BL/6J background [13 (link)] and wild type (WT) C57BL/6J mice were used for all experiments. Breeding pairs of Ldlr^−/− mice were obtained from the Jackson Laboratory (Bar Harbor, ME, USA) and Ldlr^−/− mice were bred in house. WT mice were purchased from Charles River (France). Mice were placed on a standard rodent chow diet, a high fat (HF) diet (containing 21% fat from milk butter and 0.02% cholesterol; Scientific Animal Food and Engineering, Villemoisson-sur-Orge, France), or a high fat, high cholesterol (HFC) diet (containing 21% fat from milk butter and 0.2% cholesterol; Scientific Animal Food and Engineering, Villemoisson-sur-Orge, France) for a period of 2 weeks with ad libitum access to food and water. Mice were housed individually and kept on a 12-hour light/12-hour dark cycle. Animals were anesthetized by isoflurane during all surgical operations and discomfort was minimized as much as possible. All animal experiments were approved by the ethics committee of the University of Groningen, which adheres to the principles and guidelines established by the European Convention for the Protection of Laboratory Animals.

Adult male C57BL/6J (wild type: WT) mice, V1KO mice, V4KO mice, and DKO mice (10 weeks of age, weighing 23.0–29.1 g) were used for all experiments (n = 4–8 per group). WT mice were purchased from Charles River Japan (Tokyo, Japan). V1KO mice were a kind gift from Dr. D. Julius (University of California-San Francisco), and V4KO mice were a kind gift from Dr. M. Imai (Jichi Medical University, Tochigi, Japan). After receiving permission from the Animal Experiment Committee and Gene Recombination Experiment Safety Committee, DKO mice were generated by mating TRPV1−/− with TRPV4−/− mice. Genetic ablation of both TRPV1 and TRPV4 in the F1 DKO mouse was confirmed by a polymerase chain reaction of genomic DNA extracted from the mouse tail. The DKO mice used in this study (F2) were generated from F1 DKO adult male and female mice. The result of PCR for TRPV1 and TRPV4 in WT, V1KO, V4KO, and DKO mice is shown in Supplemental Fig. S1. All mice used in the present study were housed and kept in our animal research center as described previously (Motojima et al., 2018 (link)), and all procedures were performed in accordance with the guidelines on the use and care of laboratory animals established by the Physiological Society of Japan and under the regulation of the Ethics Committee of Animal Care and Experimentation of the University of Occupational and Environmental Health of Japan.

Male and female glypican 1 knockout (Gpc1^−/−) and CD1 (wild-type, WT) mice at 5–9 weeks of age were used. WT mice were purchased from Charles River Laboratories. A breeding pair of Gpc1^−/− mice were kindly provided to us by Dr. Arthur Lander (UC Irvine). Animal experiments were conducted according to the animal protocols 18-491 and 06-036 approved by The University of Arizona Animal Care.