Department of Animal Science, "Luiz de Queiroz" College of Agriculture, University of São Paulo/ESALQ, Piracicaba, SP 13418-900, Brazil.
Embrapa Pecuária Sudeste, São Carlos, SP 13560-970, Brazil.
J Proteomics. 2018 May 15;179:30-41. doi: 10.1016/j.jprot.2018.02.028. Epub 2018 Mar 3.
The pathways involved in intramuscular fat (IMF) deposition in Longissimus dorsi muscle were investigated using an integrated transcriptome-assisted label-free quantitative proteomic approach by High Definition Mass Spectrometry. We quantified 1582 proteins, of which 164 were differentially abundant proteins (DAPs, p < 0.05) between animals with high (H) and low (L) genomic estimated breeding values (GEBV) for IMF content. Ingenuity pathway analysis (IPA) revealed that these DAPs were mainly involved in glycolysis metabolism, actin cytoskeleton signaling, cell-cell adherens junction and pathways for MAPK and insulin. A comparative study between transcriptomic (mRNA) and proteomic data showed 17 differentially expressed genes corresponding to DAPs, of which three genes/proteins did not agree on the direction of the fold change between groups. Moreover, we investigated microRNAs data to explain these differences in fold change direction, being able to unravel two of the three unexpected mRNA/protein relationships. Results demonstrated that changes in protein/mRNA levels of sarcomere organization, intracellular signal transduction and regulation of actin cytoskeleton, are involved in IMF deposition. These findings provide a deeper understanding of the highly complex regulatory mechanisms involved in IMF deposition in cattle and indicate target pathways for future studies.
Intramuscular fat is the amount of fat deposited inside muscle and plays an important role in human health and meat quality attributes, influencing energy metabolism of skeletal muscle, as well as, tenderness, flavor, and juiciness of beef. We performed for the first time the utilization of integrated transcriptome-assisted label-free quantitative proteomic approach using High Definition Mass Spectrometry for characterization of the changes in the proteomic profile of the Longissimus dorsi muscle associated with intramuscular fat deposition in cattle. Furthermore, we compared the muscle proteome with the muscle transcriptome (mRNA and microRNAs), obtained by RNA-sequencing, to better understand the relationship between expression of mRNAs and proteins and to unravel essential biological mechanisms involved in bovine skeletal muscle IMF deposition.
本研究采用高分辨质谱的转录组辅助无标记定量蛋白质组学方法，研究长肌肌内脂肪（IMF）沉积的相关途径。
我们共鉴定到 1582 种蛋白，其中 164 种蛋白在 IMF 含量高（H）和低（L）基因组估计育种值（GEBV）的动物之间存在显著差异（p < 0.05）。IPA 分析表明，这些差异蛋白主要参与糖酵解代谢、肌动蛋白细胞骨架信号、细胞间黏附连接以及 MAPK 和胰岛素途径。转录组（mRNA）和蛋白质组数据的比较研究表明，17 个差异表达基因与差异蛋白相对应，其中 3 个基因/蛋白在组间的变化倍数方向上不一致。此外，我们还研究了 microRNA 数据，以解释这些变化倍数方向的差异，能够揭示出这三个意想不到的 mRNA/蛋白关系中的两个。
肌节组织、细胞内信号转导和肌动蛋白细胞骨架调节的蛋白/mRNA 水平的变化与 IMF 沉积有关。
这些发现深入了解了牛肌内脂肪沉积中高度复杂的调控机制，并为未来的研究指明了目标途径。
肌内脂肪是沉积在肌肉内的脂肪量，对人体健康和肉质属性有重要影响，影响骨骼肌的能量代谢，以及牛肉的嫩度、风味和多汁性。本研究首次利用高分辨质谱的转录组辅助无标记定量蛋白质组学方法，对牛长肌肌内脂肪沉积相关的蛋白质组变化进行了描述。此外，我们将肌肉蛋白质组与通过 RNA-seq 获得的肌肉转录组（mRNA 和 microRNA）进行了比较，以更好地理解 mRNA 和蛋白质表达之间的关系，并揭示参与牛骨骼肌 IMF 沉积的重要生物学机制。
