Hydrogen peroxide production regulates the mitochondrial function in insulin resistant muscle cells: Effect of catalase overexpression

Abstract

The mitochondrial redox state plays a central role in the link between mitochondrial overloading and insulin resistance. However, the mechanism by which the ROS induce insulin resistance in skeletal muscle cells is not completely understood. We examined the association between mitochondrial function and H2O2 production in insulin resistant cells. Our hypothesis is that the low mitochondrial oxygen consumption leads to elevated ROS production by a mechanism associated with reduced PGC1α transcription and low content of phosphorylated CREB. The cells were transfected with either the encoded sequence for catalase overexpression or the specific siRNA for catalase inhibition. After transfection, myotubes were incubated with palmitic acid (500μM) and the insulin response, as well as mitochondrial function and fatty acid metabolism, was determined. The low mitochondrial oxygen consumption led to elevated ROS production by a mechanism associated with β-oxidation of fatty acids. Rotenone was observed to reduce the ratio of ROS production. The elevated H2O2 production markedly decreased the PGC1α transcription, an effect that was accompanied by a reduced phosphorylation of Akt and CREB. The catalase transfection prevented the reduction in the phosphorylated level of Akt and upregulated the levels of phosphorylated CREB. The mitochondrial function was elevated and H2O2 production reduced, thus increasing the insulin sensitivity. The catalase overexpression improved mitochondrial respiration protecting the cells from fatty acid-induced, insulin resistance. This effect indicates that control of hydrogen peroxide production regulates the mitochondrial respiration preventing the insulin resistance in skeletal muscle cells by a mechanism associated with CREB phosphorylation and β-oxidation of fatty acids.

Soil Chemical Attributes and Their Influence on Elemental Composition of Yerba Mate Leaves

“…Manganese is an integral part of superoxide dismutase (SOD) structure, an enzyme that catalyzes the dismutation of O 2-and H2O2 (BARBOSA et al, 2013). These enzymes are responsible for the detoxification of oxygen free radicals (ROS), both in vegetable cells and animal cells.…”

Palmitate-Induced Cell Death and Mitochondrial Respiratory Dysfunction in Myoblasts are Not Prevented by Mitochondria-Targeted Antioxidants

“…Increased production of hydrogen peroxide associated with insulin resistance was observed also in rodents on high fat diet with no change in mitochondrial respiratory function [13]. There are several studies in cultured skeletal muscle cells showing an increase of mitochondrial ROS production induced by palmitate [14,15,16] accompanied by mtDNA damage and some features of mitochondrial dysfunction [17,18]. Mitochondrial DNA has an important role in the regulation of mitochondrial respiration and oxidative damage of mtDNA was postulated as an initial event leading to mitochondrial dysfunction [18].…”

Molecular Mechanisms and Physiological Significance of Organelle Interactions and Cooperation

“…However, the underlying physiological mechanisms are still poorly understood, and it remains to be determined whether peroxisomal H 2 O 2 exerts its action on mitochondria directly (e.g., via a RIRR response) or indirectly through the activation of non-mitochondrial stress response pathways. In this context, it is interesting to note that inhibition of peroxisomal catalase activity rapidly leads to a decrease in mitochondrial aconitase activity in early-passage human fibroblasts (Walton and Pizzitelli, 2012) and a reduced phosphorylation of CREB1 and PGC1α transcription in skeletal muscle cells (CREB1 is a cAMP response element binding protein that activates the transcription of PGC1α, a transcriptional co-activator critical for mitochondrial biogenesis and function) (Barbosa et al, 2013).…”

“…As (i) peroxisomes contain copious amounts of enzymes that can produce or degrade H 2 O 2 (see Pro-oxidant Systems and Antioxidant Systems), (ii) peroxisomal H 2 O 2 can leak into the cytosol (Mueller et al, 2002), and (iii) changes in catalase activity (and hence in peroxisomal H 2 O 2 metabolism) have a profound impact on mitochondrial redox balance (see Peroxisomes and Mitochondria Share an Intricate Redox-sensitive Relationship) and respiration (Barbosa et al, 2013), it is plausible to suppose that peroxisome-derived H 2 O 2 can act as a signaling molecule between peroxisomes and mitochondria (Camões et al, 2014). However, the underlying physiological mechanisms are still poorly understood, and it remains to be determined whether peroxisomal H 2 O 2 exerts its action on mitochondria directly (e.g., via a RIRR response) or indirectly through the activation of non-mitochondrial stress response pathways.…”

“…For example, as H 2 O 2 can diffuse out of peroxisomes (see Hydrogen Peroxide), it is very likely that this molecule can modulate the activity of extra-peroxisomal redox-sensitive proteins (e.g., transcription factors, kinases, and phosphatases) involved in the (transcriptional) control of mitochondrial biogenesis and function. One such example may be AKT1, a serine-threonine protein kinase that positively regulates the activity of CREB1 [see Hydrogen Peroxide and (Barbosa et al, 2013)] and is degraded by the ubiquitin-mediated proteasome pathway in conditions with elevated H 2 O 2 . As the biological halflife of some ROS is extremely short (e.g., O…”