The unique circulating microRNAs (miRNAs) observed in patients with type 2 diabetes (T2D) are candidates as new biomarkers and therapeutic targets. In order to identify circulating miRNAs relevant to the disease process in case of type 2 diabetes, we performed the Illumina sequencing of miRNAs derived from the serum, liver and epididymal white adipose tissue (WAT) of diet-induced obese male C57BL/6J mice.

We selected four miRNAs, miR-101, miR-335, miR-375, and miR-802, which are increased in the sera and tissues of obese mice, and measured the serum levels of miRNAs in T2D and subjects with normal glucose tolerance (NGT).

The serum concentrations of miRNAs, log₁₀miR-101, log₁₀miR-375, and log₁₀miR-802, were significantly increased in the T2D patients compared with NGT subjects (1.41 ± 2.01 v.s. − 0.57 ± 1.05 (P = 1.36 × 10^− 5), 0.20 ± 0.58 v.s. 0.038 ± 1.00 (P = 3.06 × 10^− 6), and 2.45 ± 1.27 v.s. 0.97 ± 0.98 (P = 0.014), respectively). The log₁₀miR-335 values did not demonstrate any significant differences between the T2D and NGT groups (− 1.08 ± 1.35 v.s. − 0.38 ± 1.21 (P = 0.25)). According to the stepwise regression analysis, the HbA1c was an independent predictor of miR-101. Regarding the serum miR-802 levels, eGFR, HbA1c and HDL-C values were identified as significant determinants.

The present findings demonstrated that the circulating miR-101, miR-375 and miR-802 levels are significantly increased in T2D patients versus NGT subjects and they may become the new biomarkers for type 2 diabetes.