Background: Phosphoprotein enriched in diabetes (PED) is a scaffold protein widely produced in different tissues; it is involved in multiple cellular functions, including insulin-regulated glucose transport. Previous findings showed that in individuals with type 2 diabetes (T2D) the PED gene is overexpressed in skeletal muscle (SM) and adipose tissue (AT), both target tissues for insulin activity. Our group has recently evidenced that PED protein is also expressed in peripheral blood leucocytes (PBLs) and overexpressed in about 30% of diabetics.
Aim: To investigate the presence of any correlation in PED expression between PBLs and insulin-sensitive tissues, in order to validate this method as a possible screening in at-risk subjects for T2D.
Subjects and methods: 21 subjects were recruited: 14 euglycaemic (7 T2D first degree relatives (FDR) and 7 without T2D family history) and 7 T2D patients. We evaluated PED protein expression analysing lysates from AT and SM, and PBLs by immunoblotting with specific PED antibodies.
Results: A two-fold increase in PED levels in AT and SM was found both in T2D patients and in FDR, compared with euglycaemic controls. On the whole, PED levels were 30% higher in PBLs than in SM and AT (P<0.001) from the same subjects. Moreover, in all subjects there were significant correlations between PED levels in the PBLs and those in AT and in SM (P<0.001).
Conclusions: PED expression can be detected in PBLs and its expression is correlated with that in insulin-sensitive tissues. Therefore, this method could become a valid aid to identify at-risk individuals for diabetes in large scale studies.