Docking protein 1 and free fatty acids are associated with insulin resistance in patients with type 2 diabetes mellitus

OBJECTIVE: Insulin resistance (IR) is a key defect in type 2 diabetes mellitus (T2DM); therefore, effective means of ameliorating IR are sought. METHODS: We performed a retrospective cohort study of 154 patients with T2DM and 39 with pre-diabetes (pre-DM). The effects of IR and a high concentration of FFA on gene expression were determined using microarray analysis and quantitative reverse transcription polymerase chain reaction (RT-qPCR) in patients with T2DM or pre-DM. RESULTS: Serum FFA concentration and homeostasis model assessment of IR (HOMA-IR) were significantly higher in patients with T2DM but no obesity and in those with pre-DM than in controls. HOMA-IR was significantly associated with T2DM. RT-qPCR showed that the expression of FBJ murine osteosarcoma viral oncogene homolog (FOS) and AE binding protein 1 (AEBP1) was much lower in the circulation of participants with obesity and diabetes. RT-qPCR showed that the expression of docking protein 1 (DOK1) was significantly lower in the blood of participants with diabetes but no obesity and in those with pre-DM than in controls. CONCLUSIONS: FFA and DOK1 are associated with IR in patients with T2DM but no obesity or pre-DM. The downregulation of DOK1 might inhibit lipid synthesis and induce lipolysis, inducing or worsening IR.