Using TRAC to investigate the regulation of adipose tissue lipid metabolism

Energy metabolism disorders such as diabetes are complex multi-tissue and multi-genic diseases, involving a range of cell types and biochemical pathways. Recently, Metabolex, a specialist in the treatment of type 2 diabetes, used TRAC to investigate the expression of genes likely to be important during lipid formation and storage. High fatty acid levels are strong predictors of muscle insulin resistance and muscle fat content is increased in type 2 diabetes.

The genes studied included transcription factors implicated in the regulation of glucose and lipid metabolism, key enzymes and kinases for glucose and lipid homeostasis, as well as house-keeping genes for normalization.

Until now, this experiment had not been contemplated due to resource constraints, prohibitive cost and comparability issues across tests imposed by using traditional techniques such as microarrays or qPCR. TRAC provides cost-effective and rapid gene multiplexing with high sample throughput, making this study feasible for the first time.

Methods

This experiment compared mice fed on a normal chow diet with those fed on a high fat diet, such as that likely to increase adipose tissue formation and lipid storage. In addition, wild type mice were compared to knock outs for a protein known as receptor A, which had previously been shown to be important during lipogenesis under high fat conditions in mice.

Using TRAC, the researchers were able to study expression of 20 genes in more than 200 muscle, adipose and liver tissue samples from wild type and Receptor A knock-out mice, fed on a normal chow or high fat diet. This generated over 10,000 data points quickly, efficiently and cost-effectively.

Results

In this investigation, the researchers identified two genes that were upregulated in the liver tissue of mice fed on a high fat diet, designated Gene X-2 and Gene X-3 (so named as they are proprietary to Metabolex).  Similar results were seen in muscle and adipose tissues. This upregulation could be mimicked in mice fed on a normal diet by knocking out Receptor A, indicating that both the two genes and the receptor may function in the same pathway (see Figure 1).

Metabolism figure

Figure 1. Gene X-2 and Gene X-3 levels are upregulated in Receptor A knock out mice

The results led to the development of a new model for the mechanism of action of lipogenesis, and suggested that Gene X-2 and Gene X-3 might be valuable new targets for therapeutic modulation. In addition, these genes could act as biomarkers for Receptor A activation when studying lipogenesis. Due to the quality and promise of the data obtained, the company plans to investigate this pathway in more detail in the future.

To see how TRAC could help you rapidly and accurately investigate a large panel of genes in hundreds to thousands of samples, contact us now.