DANTROLENE REDUCES SERUM TNFα AND CORTICOSTERONE LEVELS AND MUSCLE CALCIUM, CALPAIN GENE EXPRESSION, AND PROTEIN BREAKDOWN IN SEPTIC RATS

Fischer, David; Sun, Xiaoyan; Williams, Amanda D.; Gang, Guy; Pritts, Timothy A.; James, Howard; Molloy, Mark P.; Fischer, Josef E.; Rutgeerts, Paul; Hasselgren, Per-Olof J.

doi:10.1097/00024382-200115030-00007

Cited by 57 publications

(59 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Several previous studies examining animal models of sepsis have reported increases in resting skeletal muscle cytosolic calcium concentrations in response to this stress (21,22), and this increase in calcium represents one possible mechanism by which endotoxin administration may have induced activation of diaphragmatic calpain in the present experiments.…”

Section: Discussion Calpain Activation In Sepsissupporting

confidence: 54%

Calpain Activation Contributes to Endotoxin-Induced Diaphragmatic Dysfunction

Supinski

Callahan

2010

Am J Respir Cell Mol Biol

View full text Add to dashboard Cite

Calpain activation occurs in skeletal muscle in response to infection, but it is unknown if calpain inhibition improves muscle functional capacity. We hypothesized that infection induces diaphragm calpain activation, that calpain activation results in cleavage of important diaphragm cytoskeletal proteins, and that inhibition of calpain attenuates infection-induced diaphragm dysfunction. Mice (n 5 4-6/group) were given: (1) saline (intraperitoneal); (2) endotoxin (12 mg/kg intraperitoneal); (3) calpain inhibitor peptide III (12 mg/kg intraperitoneal); and (4) endotoxin (12 mg/kg) plus calpain inhibitor peptide III (12 mg/kg). At 24 hours, diaphragms were removed and the following determined: (1) calpain activity by fluorogenic assay; (2) calpain I and II protein levels; (3) talin protein levels; and (4) the force-frequency relationship. Endotoxin significantly increased diaphragm calpain activity (P , 0.001), active calpain I protein (P , 0.001), active calpain II protein (P , 0.01), levels of a calpain-specific cleavage talin degradation product (P , 0.003), and reduced diaphragm force (P , 0.001). Calpain inhibitor III administration prevented endotoxin-induced increases in calpain activity, reduced talin degradation, and attenuated reductions in diaphragm force. Diaphragm-specific force at 150 Hz stimulation was significantly higher in control, endotoxin plus calpain inhibitor III, and calpain inhibitor III alone groups (23 6 1, 20 6 1 and 23 6 1 N/cm 2 , respectively) than in the endotoxin alone group (15 6 1 N/cm 2 ) (P , 0.01). This model of sepsis results in significant diaphragm calpain activation and calpain-dependent diaphragm cytoskeletal protein cleavage. Moreover, calpain inhibition attenuates endotoxin-induced diaphragm weakness, suggesting that such inhibitors may be a potential treatment to improve respiratory muscle function in infected patients.

show abstract

Section: Discussion Calpain Activation In Sepsissupporting

confidence: 54%

Calpain Activation Contributes to Endotoxin-Induced Diaphragmatic Dysfunction

Supinski

Callahan

2010

Am J Respir Cell Mol Biol

View full text Add to dashboard Cite

show abstract

“…Support for a role of calpains in muscle wasting comes from previous studies in which we found that the mRNA expression of calpains was increased in muscle from septic rats (16,50). Reduced muscle calcium levels and inhibited protein breakdown after treatment with the calcium antagonist dantrolene provided further support for the concept that muscle protein breakdown in various catabolic conditions is at least in part regulated by a calcium-dependent proteolytic mechanism (16).…”

supporting

confidence: 67%

“…Reduced muscle calcium levels and inhibited protein breakdown after treatment with the calcium antagonist dantrolene provided further support for the concept that muscle protein breakdown in various catabolic conditions is at least in part regulated by a calcium-dependent proteolytic mechanism (16). On the basis of those and similar observations, we and others have proposed a model in which calpains provide an early, and perhaps rate-limiting, step in muscle wasting, accounting for degradation of Z-band-associated proteins, in particular titin and ␣-actinin and resulting in release of myosin and actin from the myofibrils (17,19,25,41,42,50).…”

mentioning

confidence: 69%

“…Sepsis was induced in male Sprague-Dawley rats (50 -60 g) by cecal ligation and puncture (CLP), as described in detail previously (16,21,44,50). Control rats underwent sham operation, i.e., laparotomy and manipulation, but no ligation or puncture of the cecum.…”

Section: Methodsmentioning

confidence: 99%

“…One reason for this is that previous reports on calpain activity have been conflicting. For example, during sepsis, both increased (3) and unchanged (16) calpain activity in skeletal muscle have been reported. One reason why previous results were apparently conflicting may be differences in experimental models and methods used for the measurement of calpain activity, including differences in the substrate used in the assay and the method used for extraction of muscle proteins.…”

mentioning

confidence: 99%

See 2 more Smart Citations

Sepsis stimulates calpain activity in skeletal muscle by decreasing calpastatin activity but does not activate caspase-3

Wei¹,

Fareed²,

Evenson³

et al. 2005

American Journal of Physiology-Regulatory, Integrative and Comp

Self Cite

View full text Add to dashboard Cite

, and Per-Olof Hasselgren. Sepsis stimulates calpain activity in skeletal muscle by decreasing calpastatin activity but does not activate caspase-3. Am J Physiol Regul Integr Comp Physiol 288: R580 -R590, 2005. First published November 24, 2004 doi:10.1152/ajpregu.00341.2004.-We examined the influence of sepsis on the expression and activity of the calpain and caspase systems in skeletal muscle. Sepsis was induced in rats by cecal ligation and puncture (CLP). Control rats were sham operated. Calpain activity was determined by measuring the calcium-dependent hydrolysis of casein and by casein zymography. The activity of the endogenous calpain inhibitor calpastatin was measured by determining the inhibitory effect on calpain activity in muscle extracts. Protein levels of -and m-calpain and calpastatin were determined by Western blotting, and calpastatin mRNA was measured by real-time PCR. Caspase-3 activity was determined by measuring the hydrolysis of the fluorogenic caspase-3 substrate Ac-DEVD-AMC and by determining protein and mRNA expression for caspase-3 by Western blotting and real-time PCR, respectively. In addition, the role of calpains and caspase-3 in sepsis-induced muscle protein breakdown was determined by measuring protein breakdown rates in the presence of specific inhibitors. Sepsis resulted in increased muscle calpain activity caused by reduced calpastatin activity. In contrast, caspase-3 activity, mRNA levels, and activated caspase-3 29-kDa fragment were not altered in muscle from septic rats. Sepsis-induced muscle proteolysis was blocked by the calpain inhibitor calpeptin but was not influenced by the caspase-3 inhibitor Ac-DEVD-CHO. The results suggest that sepsis-induced muscle wasting is associated with increased calpain activity, secondary to reduced calpastatin activity, and that caspase-3 activity is not involved in the catabolic response to sepsis.

show abstract

Dexamethasone and corticosterone induce similar, but not identical, muscle wasting responses in cultured L6 and C2C12 myotubes

Menconi

Gonnella

Petkova

et al. 2008

J of Cellular Biochemistry

Self Cite

150

168

View full text Add to dashboard Cite

Dexamethasone-treated L6 (a rat cell line) and C2C12 (a mouse cell line) myotubes are frequently used as in vitro models of muscle wasting. We compared the effects of different concentrations of dexamethasone and corticosterone (the naturally occurring glucocorticoid in rodents) on protein breakdown rates, myotube size, and atrogin-1 and MuRF1 mRNA levels in the two cell lines. In addition, the expression of the glucocorticoid receptor (GR) and its role in glucocorticoid-induced metabolic changes were determined. Treatment with dexamethasone or corticosterone resulted in dose-dependent increases in protein degradation rates in both L6 and C2C12 myotubes accompanied by 25-30% reduction of myotube diameter. The same treatments increased atrogin-1 mRNA levels in L6 and C2C12 myotubes but, surprisingly, upregulated the expression of MuRF1 in L6 myotubes only. Both cell types expressed the GR and treatment with dexamethasone or corticosterone downregulated total cellular GR levels while increasing nuclear translocation of the GR in both L6 and C2C12 myotubes. The GR antagonist RU38486 inhibited the dexamethasoneand corticosterone-induced increases in atrogin-1 and MuRF1 expression in L6 myotubes but not in C2C12 myotubes. Interestingly, RU38486 exerted agonist effects in the C2C12, but not in the L6 myotubes. The present results suggest that muscle wasting-related responses to dexamethasone and corticosterone are similar, but not identical, in L6 and C2C12 myotubes. Most notably, the regulation by glucocorticoids of MuRF1 and the role of the GR may be different in the two cell lines. These differences need to be taken into account when cultured myotubes are used in future studies to further explore mechanisms of muscle wasting.

show abstract

DANTROLENE REDUCES SERUM TNFα AND CORTICOSTERONE LEVELS AND MUSCLE CALCIUM, CALPAIN GENE EXPRESSION, AND PROTEIN BREAKDOWN IN SEPTIC RATS

Cited by 57 publications

References 0 publications

Calpain Activation Contributes to Endotoxin-Induced Diaphragmatic Dysfunction

Calpain Activation Contributes to Endotoxin-Induced Diaphragmatic Dysfunction

Sepsis stimulates calpain activity in skeletal muscle by decreasing calpastatin activity but does not activate caspase-3

Dexamethasone and corticosterone induce similar, but not identical, muscle wasting responses in cultured L6 and C2C12 myotubes

Contact Info

Product

Resources

About