Effects of the DUSP6 gene on the proliferation and differentiation of porcine subcutaneous preadipocytes

Objective: Dual-specificity protein phosphatase 6 (DUSP6), also known as mitogen-activated protein kinase phosphatase 3 (MKP-3), was considered as a functional candidate gene for white fat accumulation in mice. However, the physiological function of the DUSP6 gene on white adipocyte adipogenesis in farm animals remains unknown. In this study, we aimed to clarify the effect of DUSP6 on porcine subcutaneous preadipocyte proliferation and differentiation. Methods: We first make clear that the patterns of DUSP6 expression is associated with fat contents in porcine fat deposition related tissues. Porcine subcutaneous preadipocytes were isolated and induced to differentiation. Small interfering RNAs were applied to deplete DUSP6. MTT assay, CCK-8 analysis, Oil Red O staining, triglyceride determination and reverse transcription quantitative polymerase chain reaction were applied to study the regulatory role of DUSP6 during adipocyte adipogenesis in pigs. Results: We found that the expression levels of DUSP6 were significantly higher in backfat and longissimus dorsi tissues from fat-type pigs than in those from lean-type pigs. Consistently, the significantly induced expression of DUSP6 was also observed in differentiated adipocytes. In addition, knockdown of DUSP6 greatly inhibited preadipocytes proliferation, through the decreased cell viability and downregulated mRNA expressions of cell proliferation-associated genes, including PCNA, CDK1, CDK2. Furthermore, knockdown of DUSP6 significantly inhibited preadipocytes differentiation, as evidenced by markedly reduced lipid droplet formation, attenuated triglyceride accumulation and downregulated expression levels of adipogenic transcription masters (PPARγ, C/EBPβ, FASN and FABP4) in DUSP6 knockdown cells. Conclusion: Our results demonstrate that DUSP6 is required for white adipocyte adipogenesis in pigs.