Fiber phenotype and coenzyme Q₁₀ content in Turkey skeletal muscles

An Overview of Analytical Methods for Quantitative Determination of Coenzyme Q10 in Foods

Food analysts have developed three primary techniques for coenzyme Q10 (CoQ10) production: isolation from animal or plant matrices, chemical synthesis, and microbial fermentation; this literature review is focused on the first method. Choosing the appropriate analytical method for determining CoQ10 in a particular food product is essential, as this analyte is a quality index for healthy foods; various associations of extraction and quantification techniques are available in the literature, each having advantages and disadvantages. Several factors must be considered when selecting an analytical method, such as specificity, linear range, detection limit, quantification limit, recovery rate, operation size, analysis time, equipment availability, and costs. In another train of thought, the food sector produces a significant amount of solid and liquid waste; therefore, waste-considered materials can be a valuable source of CoQ10 that can be recovered and used as a fortifying ingredient or dietary supplement. This review also pursues identifying the richest food sources of CoQ10, and has revealed them to be vegetable oils, fish oil, organs, and meat.

Zoledronic acid induces ferroptosis by reducing ubiquinone and promoting HMOX1 expression in osteosarcoma cells

Aims: Ferroptosis plays important roles in tumorigenesis and cancer therapy. Zoledronic acid is known to inhibit the activity of farnesyl pyrophosphate synthase, a key enzyme in the mevalonate pathway. We examined whether zoledronic acid can inhibit the growth of osteosarcoma cells by inducing ferroptosis. Methods: Cell viability was analyzed by using CCK8 reagent and counting cells with trypan blue exclusion. Ferroptosis markers including lipid peroxide and PTGS2 expression were examined by flow cytometry, western blot, and quantitative PCR analyses. Cellular ubiquinone content was determined using high performance liquid chromatography. Ferrostatin-1 and RSL3 were used as the ferroptosis inhibitor and inducer respectively. Results: Zoledronic acid treatment decreased cell viability and promoted the increase in lipid peroxide content and PTGS2 expression. Addition of ferrostatin-1 reverted these effects of zoledronic acid on osteosarcoma cells, supporting a role of zoledronic acid in inducing ferroptosis. Mechanistically, zoledronic acid significantly decreased ubiquinone, a metabolite of the mevalonate pathway. Treating cells with exogenous ubiquinone prevented zoledronic acid-induced ferroptosis and decrease in the growth of osteosarcoma cells. In addition, zoledronic acid enhanced the expression of HMOX1, whereas knockdown of HMOX1 inhibited the zoledronic acid-induced increase in lipid peroxide level and decrease in cell growth. Finally, zoledronic acid together with RSL3 significantly enhanced the inhibitory effect on the growth of osteosarcoma cells. Conclusion: Our results indicate that zoledronic acid induces ferroptosis by decreasing ubiquinone content and promoting HMOX1 expression in osteosarcoma cells. Zoledronic acid together with ferroptosis inducer may be a promising new strategy for the treatment of osteosarcoma.

L-Carnosine Stimulation of Coenzyme Q10 Biosynthesis Promotes Improved Mitochondrial Function and Decreases Hepatic Steatosis in Diabetic Conditions

Mitochondrial dysfunction in type 2 diabetes leads to oxidative stress, which drives disease progression and diabetes complications. L-carnosine, an endogenous dipeptide, improves metabolic control, wound healing and kidney function in animal models of type 2 diabetes. Coenzyme Q (CoQ), a component of the mitochondrial electron transport chain, possesses similar protective effects on diabetes complications. We aimed to study the effect of carnosine on CoQ, and assess any synergistic effects of carnosine and CoQ on improved mitochondrial function in a mouse model of type 2 diabetes. Carnosine enhanced CoQ gene expression and increased hepatic CoQ biosynthesis in db/db mice, a type 2 diabetes model. Co-administration of Carnosine and CoQ improved mitochondrial function, lowered ROS formation and reduced signs of oxidative stress. Our work suggests that carnosine exerts beneficial effects on hepatic CoQ synthesis and when combined with CoQ, improves mitochondrial function and cellular redox balance in the liver of diabetic mice. (4) Conclusions: L-carnosine has beneficial effects on oxidative stress both alone and in combination with CoQ on hepatic mitochondrial function in an obese type 2 diabetes mouse model.

Secondary coenzyme Q deficiency in neurological disorders

Coenzyme Q (CoQ) is a ubiquitous lipid serving essential cellular functions. It is the only component of the mitochondrial respiratory chain that can be exogenously absorbed. Here, we provide an overview of current knowledge, controversies, and open questions about CoQ intracellular and tissue distribution, in particular in brain and skeletal muscle. We discuss human neurological diseases and mouse models associated with secondary CoQ deficiency in these tissues and highlight pharmacokinetic and anatomical challenges in exogenous CoQ biodistribution, recent improvements in CoQ formulations and imaging, as well as alternative therapeutical strategies to CoQ supplementation. The last section proposes possible mechanisms underlying secondary CoQ deficiency in human diseases with emphasis on neurological and neuromuscular disorders.

Differential ammonia metabolism and toxicity between avian and mammalian species, and effect of ammonia on skeletal muscle: A comparative review

Comparative aspects of ammonia toxicity, specific to liver and skeletal muscle and skeletal muscle metabolism between avian and mammalian species are discussed in the context of models for liver disease and subsequent skeletal muscle wasting. The purpose of this review is to present species differences in ammonia metabolism and to specifically highlight observed differences in skeletal muscle response to excess ammonia in avian species. Ammonia, which is produced during protein catabolism and is an essential component of nucleic acid and protein biosynthesis, is detoxified mainly in the liver. While the liver is consistent as the main organ responsible for ammonia detoxification, there are evolutionary differences in ammonia metabolism and nitrogen excretory products between avian and mammalian species. In patients with liver disease and all mammalian models, inadequate ammonia detoxification and successive increased circulating ammonia concentration, termed hyperammonemia, leads to severe skeletal muscle atrophy, increased apoptosis and reduced protein synthesis, altogether having deleterious effects on muscle size and strength. Previously, an avian embryonic model, designed to determine the effects of increased circulating ammonia on muscle development, revealed that ammonia elicits a positive myogenic response. Specifically, induced hyperammonemia in avian embryos resulted in a reduction in myostatin, a well-known inhibitor of muscle growth, expression, whereas myostatin expression is significantly increased in mammalian models of hyperammonemia. These interesting findings imply that species differences in ammonia metabolism allow avians to utilize ammonia for growth. Understanding the intrinsic physiological mechanisms that allow for ammonia to be utilized for growth has potential to reveal novel approaches to muscle growth in avian species and will provide new targets for preventing muscle degeneration in mammalian species.

The clinical heterogeneity of coenzyme Q10 deficiency results from genotypic differences in the Coq9 gene

Primary coenzyme Q10 (CoQ10) deficiency is due to mutations in genes involved in CoQ biosynthesis. The disease has been associated with five major phenotypes, but a genotype-phenotype correlation is unclear. Here, we compare two mouse models with a genetic modification in Coq9 gene (Coq9(Q95X) and Coq9(R239X)), and their responses to 2,4-dihydroxybenzoic acid (2,4-diHB). Coq9(R239X) mice manifest severe widespread CoQ deficiency associated with fatal encephalomyopathy and respond to 2,4-diHB increasing CoQ levels. In contrast, Coq9(Q95X) mice exhibit mild CoQ deficiency manifesting with reduction in CI+III activity and mitochondrial respiration in skeletal muscle, and late-onset mild mitochondrial myopathy, which does not respond to 2,4-diHB. We show that these differences are due to the levels of COQ biosynthetic proteins, suggesting that the presence of a truncated version of COQ9 protein in Coq9(R239X) mice destabilizes the CoQ multiprotein complex. Our study points out the importance of the multiprotein complex for CoQ biosynthesis in mammals, which may provide new insights to understand the genotype-phenotype heterogeneity associated with human CoQ deficiency and may have a potential impact on the treatment of this mitochondrial disorder.