Enzymes Of Phosphoryl Transfer Network Research Articles

Creatine nanoliposome reverts the HPA-induced damage in complex II–III activity of the rats’ cerebral cortex

Phenylketonuria (PKU) is a metabolic disorder accumulating phenylalanine (Phe) and its metabolites in plasma and tissues of the patients. Regardless of the mechanisms, which Phe causes brain impairment, are poorly understood, energy deficit may have linked to the neurotoxicity in PKU. It is widely recognized that creatine is involved in maintaining of cerebral energy homeostasis. Because of this, in a previous work, we incorporated it into liposomes and this increased the concentration of creatine in the cerebral cortex. Here, we examined the effect of creatine nanoliposomes on parameters of oxidative stress, enzymes of phosphoryl transfer network, and activities of the mitochondrial respiratory chain complexes (RCC) in the cerebral cortex of young rats chemically induced hyperphenylalaninemia (HPA). HPA was induced with L-phenylalanine (5.2µmol/g body weight; twice a day; s.c.), and phenylalanine hydroxylase inhibitor, α-methylphenylalanine (2.4µmol/g body weight; once a day; i.p.), from the 7th to the 19th day of life. HPA reduced the activities of pyruvate kinase, creatine kinase, and complex II + III of RCC in the cerebral cortex. Creatine nanoliposomes prevented the inhibition of the activities of the complexes II + III, caused by HPA, and changes oxidative profile in the cerebral cortex. Considering the importance of the mitochondrial respiratory chain for brain energy production, our results suggesting that these nanoparticles protect against neurotoxicity caused by HPA, and can be viable candidates for treating patients HPA.

Resveratrol and resveratrol-hydroxypropyl-β-cyclodextrin complex recovered the changes of creatine kinase and Na+, K+-ATPase activities found in the spleen from streptozotocin-induced diabetic rats.

Type 1 diabetes (T1D) is the result of the selective destruction of the pancreatic β-cells by T cells of the immune system. Although spleen is a secondary lymphoid organ, it is also involved in the T1D pathogenesis. However, the alterations in a variety of cellular processes of this disease need to be further understood. We aimed to analyze the benefits of resveratrol, and its complexed form on diabetic complications in the spleen of rats. To this end, we investigated important enzymes of phosphoryl transfer network, and Na+, K+-ATPase activity. Wistar rats were divided into non-diabetic groups: Control, Ethanol, Resveratrol, Hydroxypropyl-β-cyclodextrin, Resveratrol-hydroxypropyl-β-cyclodextrin, and diabetic groups with the same treatments. Diabetes was induced by a single dose of 60 mg/kg of streptozocin intraperitoneally, and treatments by intragastric gavage once daily for 60 days. Hyperglycemia reduced creatine kinase activity, which was reversed by the administration of resveratrol. Na+, K+-ATPase activity was greatly affected, but it was reversed by resveratrol and resveratrol-hydroxypropyl-β-cyclodextrin. This suggest an energetic imbalance in the spleen of diabetic rats, and in case this also occurs in the diabetic patients, it is possible that resveratrol supplementation could be beneficial to the better functioning of the spleen in diabetic patients.

Streptococcus agalactiae alters cerebral enzymes of phosphoryl transfer network in experimentally infected silver catfish: Impairment on brain energy homeostasis

It is recognized that phosphoryl transfer network, through the activities of creatine kinase (cytosolic and mitochondrial CK), adenylate kinase (AK) and pyruvate kinase (PK), provides new perspectives to understand the disturbances of energetic metabolism between sites of generation and utilization of adenosine triphosphate (ATP). Thus, the aim of this study was to evaluate the involvement of phosphoryl transfer network in the pathophysiology of Streptococcus agalactiae linked with central nervous system (CNS). Cerebral cytosolic and mitochondrial CK activities decreased in infected animals compared to uninfected animals, similarly to observed by cerebral AK and PK activities. Moreover, the cerebral ATP levels decreased in infected animals compared to uninfected animals. Based on these evidences, the inhibition and absence of efficient nucleocytoplasmic communication between CK isoenzymes caused an impairment on cerebral energetics. Moreover, the inhibition on hepatic AK and PK caused an impairment of communication between sites of ATP generation and ATP utilization, which is corroborated by cerebral ATP depletion. In summary, these alterations contribute to disease pathogenesis linked to CNS during fish streptococcosis.

Evaluation of Oxidative Stress Parameters and Energy Metabolism in Cerebral Cortex of Rats Subjected to Sarcosine Administration.

Sarcosine is an N-methyl derivative of the amino acid glycine, and its elevation in tissues and physiological fluids of patients with sarcosinemia could reflect a deficient pool size of activated 1-carbon units. Sarcosinemia is a rare inherited metabolic condition associated with mental retardation. In the present study, we investigated the acute effect of sarcosine and/or creatine plus pyruvate on some parameters of oxidative stress and energy metabolism in cerebral cortex homogenates of 21-day-old Wistar rats. Acute administration of sarcosine induced oxidative stress and diminished the activities of adenylate kinase, GAPDH, complex IV, and mitochondrial and cytosolic creatine kinase. On the other hand, succinate dehydrogenase activity was enhanced in cerebral cortex of rats. Moreover, total sulfhydryl content was significantly diminished, while DCFH oxidation, TBARS content, and activities of SOD and GPx were significantly enhanced by acute administration of sarcosine. Co-administration of creatine plus pyruvate was effective in the prevention of alterations provoked by sarcosine administration on the oxidative stress and the enzymes of phosphoryltransfer network. These results indicate that acute administration of sarcosine may stimulate oxidative stress and alter the energy metabolism in cerebral cortex of rats. In case these effects also occur in humans, they may contribute, along with other mechanisms, to the neurological dysfunction of sarcosinemia, and creatine and pyruvate supplementation could be beneficial to the patients.

Creatine and pyruvate prevent the alterations caused by tyrosine on parameters of oxidative stress and enzyme activities of phosphoryltransfer network in cerebral cortex of Wistar rats.

Tyrosine accumulates in inborn errors of tyrosine catabolism, especially in tyrosinemia type II. In this disease caused by tyrosine aminotransferase deficiency, eyes, skin, and central nervous system disturbances are found. In the present study, we investigated the chronic effect of tyrosine methyl ester (TME) and/or creatine plus pyruvate on some parameters of oxidative stress and enzyme activities of phosphoryltransfer network in cerebral cortex homogenates of 21-day-old Wistar. Chronic administration of TME induced oxidative stress and altered the activities of adenylate kinase and mitochondrial and cytosolic creatine kinase. Total sulfhydryls content, GSH content, and GPx activity were significantly diminished, while DCFH oxidation, TBARS content, and SOD activity were significantly enhanced by TME. On the other hand, TME administration decreased the activity of CK from cytosolic and mitochondrial fractions but enhanced AK activity. In contrast, TME did not affect the carbonyl content and PK activity in cerebral cortex of rats. Co-administration of creatine plus pyruvate was effective in the prevention of alterations provoked by TME administration on the oxidative stress and the enzymes of phosphoryltransfer network, except in mitochondrial CK, AK, and SOD activities. These results indicate that chronic administration of TME may stimulate oxidative stress and alter the enzymes of phosphoryltransfer network in cerebral cortex of rats. In case this also occurs in the patients affected by these disorders, it may contribute, along with other mechanisms, to the neurological dysfunction of hypertyrosinemias, and creatine and pyruvate supplementation could be beneficial to the patients.

Effect of Leucine Administration to Female Rats During Pregnancy and Lactation on Oxidative Stress and Enzymes Activities of Phosphoryltransfer Network in Cerebral Cortex and Hippocampus of the Offspring

Maple Syrup Urine Disease is an inborn error of metabolism caused by severe deficiency in the activity of branched-chain α-keto acid dehydrogenase complex. Neurological disorder is common in patients with maple syrup urine disease. Although leucine is considered the main toxic metabolite, the mechanisms underlying the neuropathology of brain injury are poorly understood. In the present study, we evaluated the possible preventive effect of the co-administration of creatine plus pyruvate on the effects elicited by leucine administration to female Wistar rats during pregnancy and lactation on some oxidative stress parameters as well as the activities of some enzymes involved in the phosphoryltransfer network in the brain cortex and hippocampus of the offspring at 21days of age. Leucine administration induced oxidative stress and altered the activities of pyruvate kinase, adenylate kinase, mitochondrial and cytosolic creatine kinase. Co-administration of creatine plus pyruvate was partially effective in the prevention of some alterations provoked by leucine administration on the oxidative stress but not in the enzymes of phosphoryltransfer network. These results suggest that non-treated maternal hyperleucinemia may be toxic to the brain of the offspring.