Irreversible plasma and muscle protein oxidation and physical exercise

Abstract

The imbalance between the reactive oxygen (ROS) and nitrogen (RNS) species production and their handling by the antioxidant machinery (low molecular weight antioxidant molecules and antioxidant enzymes), also known as oxidative stress, is a condition caused by physiological and pathological processes. Moreover, oxidative stress may be due to an overproduction of free radicals during physical exercise. Excess of radical species leads to the modification of molecules, such as proteinsthe most susceptible to oxidative modificationlipids and DNA. With regard to the oxidation of proteins, carbonylation is an oxidative modification that has been widely described. Several studies have detected changes in the total amount of protein carbonyls following different types of physical exercise, but only few of these identified the specific amino acidic residues targets of such oxidation. In this respect, proteomic approaches allow to identify the proteins susceptible to carbonylation and in many cases, it is also possible to identify the specific protein carbonylation sites. This review focuses on the role of protein oxidation, and specifically carbonyl formation, for plasma and skeletal muscle proteins, following different types of physical exercise performed at different intensities. Furthermore, we focused on the proteomic strategies used to identify the specific protein targets of carbonylation. Overall, our analysis suggests that regular physical activity promotes a protection against protein carbonylation, due to the activation of the antioxidant defence or of the turnover of protein carbonyls. However, we can conclude that from the comprehensive bibliography analysed, there is no clearly defined specific physiological role about this post-translational modification of proteins.

Reduced Proteasome Activity and Enhanced Autophagy in Blood Cells of Psoriatic Patients

“…These structural changes can lead to protein cross-linking, which modifies the physicochemical and biological properties of proteins, as well as decreasing their susceptibility to degradation [ 40 , 41 ]. Protein carbonylation is an irreversible process, which means that damaged molecules are not repaired, and if they are not degraded, they can strongly disrupt cellular metabolism [ 42 ]. It has been shown that as a result of oxidative modification of protein molecules, their surface hydrophobicity increases, which is a key signal for the proteolytic system to recognize the protein and initiate its degradation [ 43 ].…”

Inflammation, Peripheral Signals and Redox Homeostasis in Athletes Who Practice Different Sports

“…ROS upregulate the expression of antioxidant enzymes leading to a stimulation of the antioxidant defense system. However, an increase in ROS production or a reduction in antioxidant capacity results in an imbalance and the redox state becoming pro-oxidant causes molecular damage [41]. Elite athletes have a very strong antioxidant defense system but a prolonged and strenuous exercise without an adequate rest period can lead to oxidative damage producing protein oxidation and developing muscle fatigue, injury and overreaching/overtraining with the impairment of sport performance.…”

Immunoproteasome inhibition attenuates experimental psoriasis

“…Even though the pathogenesis of psoriasis is not fully understood, it is accepted that reactive-oxygen species (ROS) and oxidative stress contribute to disease progression ( 34 ). The resulting protein carbonylation, which was detected in patients with psoriasis ( 35 ), is irreversible and requires defective proteins to be degraded in order not to disrupt cellular metabolism ( 36 ). Such proteins are degraded mainly by the proteasome ( 37 ), which is dysregulated in many diseases ( 38 ).…”