Identification of Novel Changes in Human Skeletal Muscle Proteome After Roux-en-Y Gastric Bypass Surgery

Abstract

The mechanisms of metabolic improvements after Roux-en-Y gastric bypass (RYGB) surgery are not entirely clear. Therefore, the aim of our study was to investigate the role of obesity and RYGB on the human skeletal muscle proteome. Basal muscle biopsies were obtained from seven obese (BMI >40 kg/m(2)) female subjects (45.1 ± 3.6 years) pre- and 3 months post-RYGB, and euglycemic-hyperinsulinemic clamps were used to assess insulin sensitivity. Four age-matched (48.5 ± 4.7 years) lean (BMI <25 kg/m(2)) females served as control subjects. We performed quantitative mass spectrometry and microarray analyses on protein and RNA isolated from the muscle biopsies. Significant improvements in fasting plasma glucose (104.2 ± 7.8 vs. 86.7 ± 3.1 mg/dL) and BMI (42.1 ± 2.2 vs. 35.3 ± 1.8 kg/m(2)) were demonstrated in the pre- versus post-RYGB, both P < 0.05. Proteomic analysis identified 2,877 quantifiable proteins. Of these, 395 proteins were significantly altered in obesity before surgery, and 280 proteins differed significantly post-RYGB. Post-RYGB, 49 proteins were returned to normal levels after surgery. KEGG pathway analysis revealed a decreased abundance in ribosomal and oxidative phosphorylation proteins in obesity, and a normalization of ribosomal proteins post-RYGB. The transcriptomic data confirmed the normalization of the ribosomal proteins. Our results provide evidence that obesity and RYGB have a dynamic effect on the skeletal muscle proteome.

Figure 1

Proteomics data validated by immunoblotting analyses. The normalized ion abundance data for desmin, citrate synthase, cytochrome c, and SOD2 expressed relative to GAPDH taken from mass spectrometry (A) and immunoblot analysis comparing abundance of desmin, citrate synthase, cytochrome c, and SOD2 expressed relative to GAPDH protein in skeletal muscle biopsies from lean (n = 4), presurgery obese (n = 7), and postsurgery obese subjects (B). Data are means ± SEM. *P < 0.05, vs. lean control; +P < 0.05, postsurgery vs. presurgery.

Figure 2

Correlation analysis of protein fold changes and microarray log2 fold changes for the cytoplasmic ribosomes in the pre- vs. postsurgery subjects (A) and correlation analysis of protein fold changes and microarray log2 fold changes for the mitochondrial ribosomes in the pre- vs. postsurgery subjects (B).

Figure 3

Immunoblot analysis of RPL23A and RPS14 expressed relative to GAPDH protein in skeletal muscle biopsies from lean (n = 4), presurgery obese (n = 7), and postsurgery obese subjects. Data are means ± SEM. *P < 0.05, vs. lean control; +P < 0.05, postsurgery vs. presurgery.