Muscle proteolysis is differentially influenced by mitochondrial intactness.

Autor: Stafford CD; Department of Nutrition, Dietetics and Food Sciences, Utah State University, Logan, UT 84322, United States., Taylor MJ; Department of Nutrition, Dietetics and Food Sciences, Utah State University, Logan, UT 84322, United States., Buhler JF; Department of Nutrition, Dietetics and Food Sciences, Utah State University, Logan, UT 84322, United States., Dang DS; Department of Nutrition, Dietetics and Food Sciences, Utah State University, Logan, UT 84322, United States., Thornton KJ; Department of Animal, Dairy and Veterinary Sciences, Utah State University, Logan, UT 84322, United States., Gerrard DE; School of Animal Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, United States., Matarneh SK; Department of Nutrition, Dietetics and Food Sciences, Utah State University, Logan, UT 84322, United States. Electronic address: sulaiman.matarneh@usu.edu.
Jazyk: angličtina
Zdroj: Meat science [Meat Sci] 2024 Jan; Vol. 207, pp. 109368. Date of Electronic Publication: 2023 Oct 14.
DOI: 10.1016/j.meatsci.2023.109368
Abstrakt: This study examined the potential influence of mitochondrial calcium sequestering ability on calpain-1 autolysis and proteolysis in vitro. We first tested whether mitochondria can sequester calcium in an in vitro setting. Isolated bovine mitochondria (0, 0.5, or 2 mg/mL) were incubated in a buffer containing varying calcium levels (0, 50, or 100 μM). An inverse relationship between mitochondrial content and measured free calcium was observed (P < 0.05), confirming that mitochondria can sequester calcium within the concentration range tested. In the first in vitro experiment, intact mitochondria (0, 0.5, or 2 mg/mL) were incorporated into an in vitro model simulating postmortem muscle conditions, and calpain-1 autolysis and proteolysis were evaluated over a 168-h period. Adding intact mitochondria to the in vitro model decreased calpain-1 autolysis and proteolysis during the first 4 h of incubation (P < 0.05), likely through reducing calcium availability. However, accentuated calpain-1 autolysis and proteolysis were observed at 24 h. To further explore these effects, mitochondrial integrity was evaluated at varying pH and calcium levels. Mitochondrial integrity decreased as pH declined (P < 0.05), especially in the presence of calcium. Based on these results, we conducted a second in vitro experiment involving disrupted mitochondria. Unlike intact mitochondria, which exerted a suppressive effect on calpain-1 autolysis and proteolysis early on, disrupted mitochondria increased both parameters at most time points (P < 0.05). Overall, it appears that intact mitochondria initially cause a delay in calpain-1 autolysis and proteolysis, but as their integrity diminishes, both processes are enhanced.
Competing Interests: Declaration of Competing Interest The authors declare no conflicts of interest.
(Copyright © 2023 Elsevier Ltd. All rights reserved.)
Databáze: MEDLINE
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