NOD2 activation induces oxidative stress contributing to mitochondrial dysfunction and insulin resistance in skeletal muscle cells

• Published in: Free radical biology & medicine 2015-12, Vol.89, p.158-169
• Main Authors: Maurya, Chandan K., Arha, Deepti, Rai, Amit K., Kant Kumar, Shashi, Pandey, Jyotsana, Avisetti, Deepa R., Kalivendi, Shasi V., Klip, Amira, Tamrakar, Akhilesh K.
• Format: Article
• Language: English
• Subjects: Animals; Apoptosis; Blotting, Western; Cells, Cultured; Free radicals; Immunoenzyme Techniques; Inflammation; Innate immunity; Insulin Resistance; Membrane Potential, Mitochondrial; Mitochondria - metabolism; Mitochondria - pathology; Mitochondrial function; Muscle Fibers, Skeletal - metabolism; Muscle Fibers, Skeletal - pathology; Muscle, Skeletal - metabolism; Muscle, Skeletal - pathology; NOD; Nod2 Signaling Adaptor Protein - genetics; Nod2 Signaling Adaptor Protein - metabolism; Oxidative Stress; Phosphorylation; Rats; Reactive Oxygen Species - metabolism; Real-Time Polymerase Chain Reaction; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger - genetics; Signal Transduction
• ISSN: 0891-5849; 1873-4596
• DOI: 10.1016/j.freeradbiomed.2015.07.154

Nucleotide-binding oligomerization domain protein-2 (NOD2) activation in skeletal muscle cells has been associated with insulin resistance, but the underlying mechanisms are not yet clear. Here we demonstrate the implication of oxidative stress in the development of mitochondrial dysfunction and insulin resistance in response to NOD2 activation in skeletal muscle cells. Treatment with the selective NOD2 ligand muramyl dipeptide (MDP) increased mitochondrial reactive oxygen species (ROS) generation in L6 myotubes. MDP-induced ROS production was associated with increased levels of protein carbonyls and reduction in citrate synthase activity, cellular ATP level, and mitochondrial membrane potential, as well as altered expression of genes involved in mitochondrial function and metabolism. Antioxidant treatment attenuated MDP-induced ROS production and restored mitochondrial functions. In addition, the presence of antioxidant prevented NOD2-mediated activation of MAPK kinases and the inflammatory response. This was associated with reduced serine phosphorylation of insulin receptor substrate-1 (IRS-1) and improved insulin-stimulated tyrosine phosphorylation of IRS-1 and downstream activation of Akt phosphorylation. These data indicate that oxidative stress plays a role in NOD2 activation-induced inflammatory response and that MDP-induced oxidative stress correlates with impairment of mitochondrial functions and induction of insulin resistance in skeletal muscle cells. •NOD2 activation in muscle cells causes mitochondrial ROS generation and oxidative stress.•NOD2 activation-induced oxidative stress contributes to mitochondrial dysfunction.•Antioxidant attenuates NOD2-induced ROS production and restores mitochondrial functions.•Antioxidant prevents NOD2-mediated inflammatory response and improves insulin signaling.