GPR21 KO mice demonstrate no resistance to high fat diet induced obesity or improved glucose tolerance.

Jinghong Wang,Danny Chui,Caroline Gundel,Murielle Véniant,Helene Baribault,Zheng Pan

doi:10.12688/f1000research.7822.2

Abstract

Gpr21 KO mice generated with Gpr21 KO ES cells obtained from Deltagen showed improved glucose tolerance and insulin sensitivity when fed a high fat diet. Further mRNA expression analysis revealed changes in Rabgap1 levels and raised the possibility that Rabgap1 gene may have been modified. To assess this hypothesis a new Gpr21 KO mouse line using TALENS technology was generated. Gpr21 gene deletion was confirmed by PCR and Gpr21 and Rabgap1 mRNA expression levels were determined by RT-PCR. The newly generated Gpr21 KO mice when fed a normal or high fat diet chow did not maintain their improved metabolic phenotype. In conclusion, Rabgap1 disturbance mRNA expression levels may have contributed to the phenotype of the originally designed Gpr21 KO mice.

Highlights

The G-protein receptors (GPCRs) are the largest family of proteins targeted by drug discovery
We added the analysis of liver and brown fat (BAT) Rabgap1 mRNA expression levels
Rabgap1 mRNA expression levels in liver and BAT of Gpr21 KO mice were not changed compared to their wildtype littermate mice with the upstream primer/probe set (Figure 1C), it was dramatically decreased in liver and BAT of Gpr21 KO mice compared to their wildtype littermate mice with the downstream primer/probe set (Figure 1C)”

Summary

Materials and Methods

Animals and Gpr (Gpr TAL 29bp) KO mice generation All animal experiments were approved by the Institutional Animal Care and Use Committee of Amgen. Microarray and data analysis Tissue samples from the Deltagen Gpr knockout mice were used for microarray analysis. MRNA was isolated from 6 animals for each group using Qiagen RNeasy Mini Kit (Qiagen, Valencia, CA) and processed following the protocols described in section 2 (Eukaryotic Sample and Array Processing; 701024 rev 1) of the Affymetrix Technical manual. Oral glucose (OGTT) tolerance test 17 Gpr TAL 29bp knockout and 17 wildtype littermate mice were used in this experiment. Body weight and OGTT were measured on 11 week old mice fed a normal chow diet. Body weight and OGTT measurements were performed on 15 and 26 week-old mice (fed HFD for 4 and 15 weeks, respectively). Glucose levels were measured and blood samples were taken from the tail vein before oral glucose tolerance test (OGTT) was initiated. Significance was defined as *: P < 0.05; **: P < 0.01; ***: P < 0.001

Results

Introduction

Results and discussion