Sulforaphane Enhanced Proliferation of Porcine Satellite Cells via Epigenetic Augmentation of SMAD7

SIMPLE SUMMARY: In livestock agriculture, increasing muscle growth and meat output has been a continual hot subject. A few natural compounds have proved to have the ability to accelerate muscle growth. Sulforaphane (SFN), abundant in cruciferous vegetables, has previously been shown to enhance skeletal muscle growth. In this work, we found that SFN could activate the skeletal muscle stem cell amplification. Furthermore, the underlying mechanisms were investigated. This work contributes to our understanding of how organisms interact with environmental cues such as nutrition and indicates a potential technique to boost animal output by managing feed. Meanwhile, our research is taking us one step closer to understanding how green vegetables, such as broccoli, enhance fitness and health while reducing calorie intake. ABSTRACT: Satellite cells take an indispensable place in skeletal muscle regeneration, maintenance, and growth. However, only limited works have investigated effects of dietary compounds on the proliferation of porcine satellite cells (PSCs) and related mechanisms. Sulforaphane (SFN) at multiple levels was applied to PSCs. The PSCs’ viability and HDAC activity were measured with a WST-1 cell proliferation kit and Color-de-Lys(®) HDAC colorimetric activity assay kit. Gene expression and epigenetics modification were tested with qRT-PCR, Western blot, bisulfite sequencing, and ChIP-qPCR. This study found that SFN enhanced PSC proliferation and altered mRNA expression levels of myogenic regulatory factors. In addition, SFN inhibited histone deacetylase (HDAC) activity, disturbed mRNA levels of HDAC family members, and elevated acetylated histone H3 and H4 abundance in PSCs. Furthermore, both mRNA and protein levels of the Smad family member 7 (SMAD7) in PSCs were upregulated after SFN treatment. Finally, it was found that SFN increased the acetylation level of histone H4 in the SMAD7 promoter, decreased the expression of microRNAs, including ssc-miR-15a, ssc-miR-15b, ssc-miR-92a, ssc-miR-17-5p, ssc-miR-20a-5p, and ssc-miR-106a, targeting SMAD7, but did not impact on the SMAD7 promoter’s methylation status in PSCs. In summary, SFN was found to boost PSC proliferation and epigenetically increase porcine SMAD7 expression, which indicates a potential application of SFN in modulation of skeletal muscle growth.