Journal article
STZ-induced skeletal muscle atrophy is associated with increased p65 content and downregulation of insulin pathway without NF-κB canonical cascade activation
Acta Diabetologica, Vol.47(4), pp.315-323
2010
Abstract
Type 1 diabetes mellitus (DM)-induced skeletal muscle atrophy is associated with an increased incidence in morbidity and mortality. Although the precise mechanism of diabetes-induced skeletal muscle atrophy remains to be established, several NF-κB-dependent pro-inflammatory genes have been identified as potential therapeutic targets. Moreover, activation of NF-κB has previously been shown to be required for cytokine-induced loss of skeletal muscle proteins. Therefore, we investigated activation of the NF-κB canonical pathway, concomitant to insulin signaling activation in skeletal muscle from diabetes-induced rats. Ten rats injected with streptozotocin (STZ) 4 weeks prior to tissue extraction were compared to 10 control rats. Using total, cytosolic and nuclear protein extracts from hindlimb muscles: soleus (SOL), extensor digitorum longus (EDL), gastrocnemius (GM) and liver tissue, we assessed key proteins important for the activation of both NF-κB and insulin pathways. Insulin blood concentration decreased to 3.9 ± 1.2 mU/ml following STZ-injection resulting in hyperglycemia (17.9 ± 0.7 mmol/l). SOL, EDL and GM mass decreased, and liver mass increased following STZ injection. NF-κB/p65 content in SOL, GM and liver increased in STZ-injected rats, without any change in IκB degradation or IKK phosphorylation. Muscle NF-κB/p65 remained bound to IκB and did not translocate or bind to DNA. Although the canonical NF-κB cascade was not activated, STZ induced a decrease in insulin pathway proteins including insulin receptor (IR) and substrate (IRS-1) content and phosphorylation compared to control animals. A downregulation of insulin pathway proteins and muscle atrophy occurred in response to STZ administration, and despite increased p65 content, STZ treatment did not activate the canonical NF-κB cascade. Therefore, it is unlikely that hyperglycemia initiates skeletal muscle atrophy via activation of the NF-κB canonical pathway.
Details
- Title
- STZ-induced skeletal muscle atrophy is associated with increased p65 content and downregulation of insulin pathway without NF-κB canonical cascade activation
- Authors/Creators
- A.R. Kelleher (Author/Creator)T.J. Fairchild (Author/Creator)S. Keslacy (Author/Creator)
- Publication Details
- Acta Diabetologica, Vol.47(4), pp.315-323
- Publisher
- Springer Milan
- Identifiers
- 991005543669207891
- Copyright
- © 2010 Springer-Verlag
- Murdoch Affiliation
- Murdoch University
- Language
- English
- Resource Type
- Journal article
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- Citation topics
- 1 Clinical & Life Sciences
- 1.255 Musculoskeletal Disorders
- 1.255.1761 Muscle Wasting
- Web Of Science research areas
- Endocrinology & Metabolism
- ESI research areas
- Biology & Biochemistry