NF-κB activity in muscle from obese and type 2 diabetic subjects under basal and exercise-stimulated conditions - PubMed (original) (raw)

NF-κB activity in muscle from obese and type 2 diabetic subjects under basal and exercise-stimulated conditions

Puntip Tantiwong et al. Am J Physiol Endocrinol Metab. 2010 Nov.

Abstract

NF-κB is a transcription factor that controls the gene expression of several proinflammatory proteins. Cell culture and animal studies have implicated increased NF-κB activity in the pathogenesis of insulin resistance and muscle atrophy. However, it is unclear whether insulin-resistant human subjects have abnormal NF-κB activity in muscle. The effect that exercise has on NF-κB activity/signaling also is not clear. We measured NF-κB DNA-binding activity and the mRNA level of putative NF-κB-regulated myokines interleukin (IL)-6 and monocyte chemotactic protein-1 (MCP-1) in muscle samples from T2DM, obese, and lean subjects immediately before, during (40 min), and after (210 min) a bout of moderate-intensity cycle exercise. At baseline, NF-κB activity was elevated 2.1- and 2.7-fold in obese nondiabetic and T2DM subjects, respectively. NF-κB activity was increased significantly at 210 min following exercise in lean (1.9-fold) and obese (2.6-fold) subjects, but NF-κB activity did not change in T2DM. Exercise increased MCP-1 mRNA levels significantly in the three groups, whereas IL-6 gene expression increased significantly only in lean and obese subjects. MCP-1 and IL-6 gene expression peaked at the 40-min exercise time point. We conclude that insulin-resistant subjects have increased basal NF-κB activity in muscle. Acute exercise stimulates NF-κB in muscle from nondiabetic subjects. In T2DM subjects, exercise had no effect on NF-κB activity, which could be explained by the already elevated NF-κB activity at baseline. Exercise-induced MCP-1 and IL-6 gene expression precedes increases in NF-κB activity, suggesting that other factors promote gene expression of these cytokines during exercise.

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Figures

Fig. 1.

Fig. 1.

Basal NF-κB p50/p65 DNA-binding activity in skeletal muscle. NF-κB activity was measured in vastus lateralis muscle by EMSA. Graphic data are means ± SE. Representative blots are shown for 2–4 subjects (Sub). *P < 0.05 vs. lean group. An internal (Int) control (baboon muscle tissue) was utilized to normalize the data. To confirm the identity of the NF-κB p50/p65 band, increasing concentrations of a specific competitive (Comp) inhibitor were also tested (using sample from Sub. 8). Ob, obese; FP, free probe; T2DM, type 2 diabetes mellitus.

Fig. 2.

Fig. 2.

Effect of acute exercise on NF-κB p50/p65 activity in muscle. Biopsies were done at baseline (Ba), 40 min of exercise (Ex), and 210 min postexercise (Po), and NF-κB activity was measured by EMSA. Graphic data are means ± SE. Representative blots are shown for 1 subject/group. *P < 0.05 vs. basal of respective group. Data were normalized to the preexercise sample within each subject. FP, free probe.

Fig. 3.

Fig. 3.

NF-κB p50 and p65 protein content in muscle. Biopsies were done at Ba, Ex, and Po, and NF-κB p50 (A) and p65 content (B) were measured by Western blotting. Graphic data are means ± SE. Representative blots are shown for 1 subject/group.

Fig. 4.

Fig. 4.

IκB protein content in muscle. Biopsies were done at Ba, Ex, and Po, and IκBα (A), IκBβ1 (B), and IκBβ2 content (C) were measured by Western blotting. Graphic data are means ± SE. Representative blots are shown for 1 subject/group; *P < 0.05 vs. lean at baseline; †P < 0.05 vs. obese at baseline.

Fig. 5.

Fig. 5.

Effect of acute exercise on IL-6 (A) and monocyte chemotactic protein-1 (MCP-1; B) mRNA expression in muscle. Biopsies were done at baseline, 40 min of exercise, and 210 min postexercise, and IL-6 and MCP-1 mRNA expression were measured by real-time PCR. Data are means ± SE and normalized to lean at baseline. *P < 0.05 vs. basal of respective group.

Fig. 6.

Fig. 6.

cellular-FLICE inhibitory protein (c-FLIP) mRNA levels. c-FLIP mRNA was measured before, during, and after exercise. Data are means ± SE and normalized to lean at baseline. *P < 0.05 vs. basal of lean group; ‡P < 0.05 vs. exercise of lean group; †P < 0.05 vs. lean at baseline.

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References

    1. Al-Khalili L, Bouzakri K, Glund S, Lönnqvist F, Koistinen HA, Krook A. Signaling specificity of interleukin-6 action on glucose and lipid metabolism in skeletal muscle. Mol Endocrinol 20: 3364–3375, 2006 - PubMed
    1. Andersen P, Henriksson J. Capillary supply of the quadriceps femoris muscle of man: adaptive response to exercise. J Physiol 270: 677–690, 1977 - PMC - PubMed
    1. Arkan MC, Hevener AL, Greten FR, Maeda S, Li ZW, Long JM, Wynshaw-Boris A, Poli G, Olefsky J, Karin M. IKK-beta links inflammation to obesity-induced insulin resistance. Nat Med 11: 191–198, 2005 - PubMed
    1. Austin RL, Rune A, Bouzakri K, Zierath JR, Krook A. siRNA-mediated reduction of inhibitor of nuclear factor-kappaB kinase prevents tumor necrosis factor-alpha-induced insulin resistance in human skeletal muscle. Diabetes 57: 2066–2073, 2008 - PMC - PubMed
    1. Bakkar N, Wang J, Ladner KJ, Wang H, Dahlman JM, Carathers M, Acharyya S, Rudnicki MA, Hollenbach AD, Guttridge DC. IKK/NF-kappaB regulates skeletal myogenesis via a signaling switch to inhibit differentiation and promote mitochondrial biogenesis. J Cell Biol 180: 787–802, 2008 - PMC - PubMed

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