Obesity-associated microRNA-26b regulates the proliferation of human preadipocytes via arrest of the G1/S transition.

MicroRNAs (miRNAs) are short, 20‑24 nucleotide non‑coding RNAs, which are involved in multiple biological processes, including obesity. Our previous investigation revealed that miRNA (miR)‑26b is differentially expressed in preadipocytes and mature adipocytes in humans. However, its role in the proliferation of human preadipocytes remains to be fully elucidated. In the present study, intracellular lipid accumulation was assessed using oil red O staining and the trigycerlide (TG) content was quantified using a TG assay kit, adipogenesis associated genes and cyclin D2 were analyzed using western blotting, and the effects of miR‑26b on the proliferation of preadipocytes was investigated using Cell Counting Kit‑8 assays and cell cycle analysis. Human preadipocytes overexpressing miR‑26b exhibited increased TG content in the adipocytes. During differentiation, the protein expression levels of adipogenesis‑associated marker genes, including peroxisome proliferator‑activated receptor γ, CCAAT/enhancer‑binding protein α, fatty acid‑binding protein and hormone‑sensitive lipase were upregulated in cells overexpressing miR‑26b, compared with the negative control cells. In addition, growth of human preadipocytes overexpressing miR‑26b occurred a slower rate and more remained in the G1 phase, compared with the negative control cells. In addition, miR‑26b downregulated the protein expression of cyclin D2. These results demonstrated that miR‑26b promoted differentiation and, at least party by targeting cyclin D2, attenuated cell proliferation via arresting the G1/S transition.