scholarly journals Inhibition of cardiac proteolysis by colchicine. Selective effects on degradation of protein subclasses

1983 ◽  
Vol 210 (1) ◽  
pp. 63-71 ◽  
Author(s):  
J S Crie ◽  
J M Ord ◽  
J R Wakeland ◽  
K Wildenthal
Keyword(s):  
Protein Degradation ◽  
Total Protein ◽  
Protein Turnover ◽  
Branched Chain Amino Acids ◽  
Inhibitory Effects ◽  
Similar Extent ◽  
Specific Effects ◽  
Protein Pool ◽  
Branched Chain ◽  
Mitochondrial Cytochromes

1. The effect of colchicine (2.5 microM) on cardiac protein turnover was tested with foetal mouse hearts in organ culture. 2. Colchicine had no effect on protein synthesis, but inhibited total protein degradation by 12-18%. Lumicolchicine, which lacks colchicine's ability to disaggregate microtubules, but shares its non-specific effects, did not alter protein degradation. 3. The colchicine-induced inhibition of protein degradation was accompanied by significant changes in cardiac lysosomal enzyme activities and distribution. 4. Colchicine inhibited the degradation of organellar proteins, including mitochondrial cytochromes, more than that of cytosolic proteins. 5. Colchicine decreased the rate of myosin degradation and the rate of proteolysis of the total protein pool to a similar extent. Since the regulation of myosin degradation does not involve lysosomes, this suggests that colchicine affects non-lysosomal as well as lysosomal pathways. 6. Release of branched-chain amino acids from colchicine-treated hearts was disproportionately decreased, suggesting that colchicine increased their metabolism. 7. It is concluded that colchicine, via its actions on microtubules, exerts important inhibitory effects on cardiac proteolysis. Colchicine is especially inhibitory to the degradation of organellar proteins, including mitochondrial cytochromes. Its inhibitory effects may be mediated in part via lysosomal mechanisms, but non-lysosomal mechanisms are probably involved as well.

Can nutritional criteria help predict outcome in hospitalized patients?

1986 ◽  
Vol 32 (11) ◽  
pp. 2077-2079 ◽  
Author(s):  
V M Prabhakaran ◽  
S Pujara ◽  
A J Mills ◽  
V W Whalen
Keyword(s):  
Amino Acids ◽  
Total Protein ◽  
Fatal Outcome ◽  
Branched Chain Amino Acids ◽  
Hospitalized Patients ◽  
Predicting Outcome ◽  
Branched Chain ◽  
A Prospective Study ◽  
Index Weight ◽  
Nonessential Amino Acids

Abstract The following nutritional criteria were evaluated for their usefulness in predicting outcome in a prospective study of 66 randomly selected hospitalized patients with a variety of diagnoses: total protein, albumin, and transferrin concentrations in serum, creatinine height index, weight height index, phenylalanine/tyrosine ratio (Phe/Tyr), concentration of branched-chain amino acids in serum, and ratio of essential to nonessential amino acids in serum. The cases were followed from admission to discharge, and were classified into the following three groups: 43 "well"; 14 with "complications" but recovered; and nine "dead". Statistical analysis (Scheffe's s-test) demonstrated the means of "well" and "dead" groups to be different for total protein, albumin, transferrin, and Phe/Tyr. In individual patients the nutritional criteria, even for those with fatal outcome, were poor indicators of outcome. These nutritional criteria are useful in identifying hospitalized groups that are at maximum risk (i.e., death), but are much less useful for individual patients.

Regulation of cardiac protein balance by hydrocortisone: interaction with insulin.

1978 ◽  
Vol 234 (3) ◽  
pp. E306
Author(s):  
E E Griffin ◽  
K Wildenthal
Keyword(s):  
Protein Synthesis ◽  
Protein Degradation ◽  
Cathepsin D ◽  
Specific Activity ◽  
Branched Chain Amino Acids ◽  
Protein Balance ◽  
Net Uptake ◽  
Specific Activities ◽  
Branched Chain ◽  
Net Release

In fetal mouse hearts in organ culture the rate of protein synthesis was substantially reduced and the rate of protein degradation slightly increased by hydrocortisone in the absence of insulin, but in the presence of insulin the steroid caused a small increase in protein synthesis and a significant reduction in protein degradation. Hydrocortisone promoted the net uptake (or reduced the net release) of branched-chain amino acids independent of insulin and independent of simultaneous changes in protein balance. The specific activities of the lysosomal enzymes cathepsin D and glucosaminidase were reduced by hydrocortisone in all media, whereas the specific activity of creatine kinase increased when the medium contained insulin but decreased in the absence of insulin. It is concluded that hydrocortisone regulates cardiac protein balance via alterations both in synthesis and in degradation. Some of the hormone's myocardial effects are influenced by insulin so that hydrocortisone is anabolic in its presence but catabolic in its absence.

Intake of branched-chain amino acids influences the levels of MAFbx mRNA and MuRF-1 total protein in resting and exercising human muscle

2012 ◽  
Vol 302 (5) ◽  
pp. E510-E521 ◽  
Author(s):  
Marcus Borgenvik ◽  
William Apró ◽  
Eva Blomstrand
Keyword(s):  
Amino Acids ◽  
Resistance Exercise ◽  
Total Protein ◽  
Muscle Protein ◽  
Recovery Period ◽  
Branched Chain Amino Acids ◽  
Vastus Lateralis Muscle ◽  
Early Recovery ◽  
Placebo Condition ◽  
Branched Chain

Resistance exercise and amino acids are two major factors that influence muscle protein turnover. Here, we examined the effects of resistance exercise and branched-chain amino acids (BCAA), individually and in combination, on the expression of anabolic and catabolic genes in human skeletal muscle. Seven subjects performed two sessions of unilateral leg press exercise with randomized supplementation with BCAA or flavored water. Biopsies were collected from the vastus lateralis muscle of both the resting and exercising legs before and repeatedly after exercise to determine levels of mRNA, protein phosphorylation, and amino acid concentrations. Intake of BCAA reduced ( P < 0.05) MAFbx mRNA by 30 and 50% in the resting and exercising legs, respectively. The level of MuRF-1 mRNA was elevated ( P < 0.05) in the exercising leg two- and threefold under the placebo and BCAA conditions, respectively, whereas MuRF-1 total protein increased by 20% ( P < 0.05) only in the placebo condition. Phosphorylation of p70S6k increased to a larger extent (∼2-fold; P < 0.05) in the early recovery period with BCAA supplementation, whereas the expression of genes regulating mTOR activity was not influenced by BCAA. Muscle levels of phenylalanine and tyrosine were reduced (13–17%) throughout recovery ( P < 0.05) in the placebo condition and to a greater extent (32–43%; P < 0.05) following BCAA supplementation in both resting and exercising muscle. In conclusion, BCAA ingestion reduced MAFbx mRNA and prevented the exercise-induced increase in MuRF-1 total protein in both resting and exercising leg. Further-more, resistance exercise differently influenced MAFbx and MuRF-1 mRNA expression, suggesting both common and divergent regulation of these two ubiquitin ligases.

scholarly journals Does Branched-Chain Amino Acids Supplementation Modulate Skeletal Muscle Remodeling through Inflammation Modulation? Possible Mechanisms of Action

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Humberto Nicastro ◽  
Claudia Ribeiro da Luz ◽  
Daniela Fojo Seixas Chaves ◽  
Luiz Roberto Grassmann Bechara ◽  
Vanessa Azevedo Voltarelli ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Amino Acids ◽  
Protein Synthesis ◽  
Translation Initiation ◽  
Protein Turnover ◽  
Protein Translation ◽  
Branched Chain Amino Acids ◽  
Inflammatory Status ◽  
Branched Chain ◽  
Muscle Remodeling

Skeletal muscle protein turnover is modulated by intracellular signaling pathways involved in protein synthesis, degradation, and inflammation. The proinflammatory status of muscle cells, observed in pathological conditions such as cancer, aging, and sepsis, can directly modulate protein translation initiation and muscle proteolysis, contributing to negative protein turnover. In this context, branched-chain amino acids (BCAAs), especially leucine, have been described as a strong nutritional stimulus able to enhance protein translation initiation and attenuate proteolysis. Furthermore, under inflammatory conditions, BCAA can be transaminated to glutamate in order to increase glutamine synthesis, which is a substrate highly consumed by inflammatory cells such as macrophages. The present paper describes the role of inflammation on muscle remodeling and the possible metabolic and cellular effects of BCAA supplementation in the modulation of inflammatory status of skeletal muscle and the consequences on protein synthesis and degradation.

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