Krüppel-like factor 10 (KLF10) is transactivated by the transcription factor C/EBP and involved in early 3T3-L1 preadipocyte differentiation

Abstract

Adipose tissue stores energy and plays an important role in energy homeostasis. CCAAT/enhancer-binding protein (C/EBP) is an important early transcription factor for 3T3-L1 preadipocyte differentiation, facilitating mitotic clonal expansion (MCE) and transactivating C/EBP and peroxisome proliferator–activated receptor- (PPAR) to promote adipogenesis. C/EBP is induced early, but the expression of antimitotic C/EBP and PPAR is not induced until 48 h. The delayed expression of C/EBP and PPAR is thought to ensure MCE progression, but the molecular mechanism for this delay remains elusive. Here, we show that the zinc-finger transcription factor Krüppel-like factor 10 (KLF10) is induced after adipogenic induction and that its expression positively correlates with that of C/EBP but inversely correlates with expression of C/EBP and PPAR. C/EBP bound to the KLF10 promoter and transactivated its expression during MCE. KLF10 overexpression in 3T3-L1 preadipocyte repressed adipogenesis and decreased C/EBP and PPAR expression, whereas siRNA-mediated down-regulation of KLF10 enhanced adipogenesis and increased C/EBP and PPAR expression. Luciferase assays revealed an inhibitory effect of KLF10 on C/EBP promoter activity. Using promoter deletion and mutation analysis, we identified a KLF10-binding site within the proximal promoter region of C/EBP. Furthermore, KLF10 interacted with and recruited histone deacetylase 1 (HDAC1) to the C/EBP promoter, decreasing acetylated histone H4 on the C/EBP promoter and inactivating C/EBP transcription. Because C/EBP can transactivate PPAR, our results suggest a mechanism by which expression of C/EBP and PPAR is delayed via KLF10 expression and shed light on the negative feedback loop for C/EBP-regulated adipogenesis in 3T3-L1 preadipocyte.