Intramuscular fat (IMF) and subcutaneous fat (SCF) are important traits affecting the economics of the pork industry, in which less SCF and more IMF content is desirable. However, the mechanisms that regulate IMF and SCF content are not clear yet. In this study, we demonstrate that KLF3 (Krüppel‐like factor 3) was negatively correlated with IMF content in the longissimus dorsi muscle of Erhualian pigs. In addition, the expression level of KLF3 was significantly higher in IMF than SCF. Overexpression and knockdown experiments revealed that KLF3 could suppress adipocyte differentiation in vitro by downregulating adipogenic markers, including PPARG, C/EBPA, and FABP4. Luciferase activity analysis proved that miR‐32‐5p was able to suppress KLF3. Notably, miR‐32‐5p level was negatively correlated to KLF3 mRNA level in both IMF and SCF tissues. The same relationship was proved in samples with different IMF content. Further studies showed that miR‐32‐5p could promote adipocyte differentiation via inhibiting KLF3. Our results suggest that the miR‐32‐5p‐KLF3 pathway is involved in the regulation of differential fat deposition of IMF and SCF tissues.

中文翻译：

---

miR-32-5p通过抑制KLF3调控二花脸猪肌内脂肪的脂质积累

肌内脂肪 (IMF) 和皮下脂肪 (SCF) 是影响猪肉产业经济性的重要特征，其中需要较少的 SCF 和较多的 IMF 含量。然而，调节 IMF 和 SCF 内容的机制尚不清楚。在这项研究中，我们证明了KLF3（Krüppel 样因子 3）与二花脸猪背最长肌中的 IMF 含量呈负相关。此外，KLF3在IMF中的表达水平显着高于SCF。过表达和敲低实验表明，KLF3可以通过下调脂肪生成标志物，包括PPARG、C/EBPA来抑制体外脂肪细胞分化和FABP4。荧光素酶活性分析证明 miR-32-5p 能够抑制KLF3。值得注意的是，在 IMF 和 SCF 组织中，miR-32-5p 水平与KLF3 mRNA 水平呈负相关。在不同 IMF 含量的样本中也证明了相同的关系。进一步的研究表明，miR-32-5p 可以通过抑制KLF3促进脂肪细胞分化。我们的研究结果表明，与miR-32-5p- KLF3途径参与国际货币基金组织和SCF组织的差脂肪沉积的调节。