Effects of ubiquinol-10 on microRNA-146a expression in vitro and in vivo

Alleviating effects of coenzyme Q10 supplements on biomarkers of inflammation and oxidative stress: results from an umbrella meta-analysis

Introduction: Although several meta-analyses support the positive effect of coenzyme Q10 (CoQ10) on biomarkers of oxidative stress and inflammation, the results of some other studies reject such effects. Methods: Therefore, in this umbrella meta-analysis, we performed a comprehensive systematic search in such databases as Web of Science, PubMed, Scopus, Embase, and Google Scholar up to January 2023. Results: Based on standardized mean difference analysis, CoQ10 supplementation significantly decreased serum C-reactive protein (CRP) (ESSMD = -0.39; 95% CI: 0.77, -0.01, p = 0.042) and malondialdehyde (MDA) (ESSMD = -1.17; 95% CI: 1.55, -0.79, p < 0.001), while it increased the total antioxidant capacity (TAC) (ESSMD = 1.21; 95% CI: 0.61, 1.81, p < 0.001) and serum superoxide dismutase (SOD) activity (ESSMD = 1.08; 95% CI: 0.37, 1.79, p = 0.003). However, CoQ10 supplementation had no significant reducing effect on tumor-necrosis factor-alpha (TNF- α) (ESSMD = -0.70; 95% CI: 2.09, 0.68, p = 0.320) and interleukin-6 (IL-6) levels (ESSMD = -0.85; 95% CI: 1.71, 0.01, p = 0.053). Based on weighted mean difference analysis, CoQ10 supplementation considerably decreased TNF-α (ESWMD = -0.46, 95% CI: 0.65, -0.27; p < 0.001), IL-6 (ESWMD = -0.92, 95% CI: 1.40, -0.45; p < 0.001), and CRP levels (effect sizes WMD = -0.28, 95% CI: 0.47, -0.09; p < 0.001). Discussion: The results of our meta-analysis supported the alleviating effects of CoQ10 on markers of inflammation cautiously. However, CoQ10 had antioxidant effects regarding the improvement of all the studied antioxidant and oxidative stress biomarkers. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=323861, identifier CRD42022323861.

Efficacy and Optimal Dose of Coenzyme Q10 Supplementation on Inflammation-Related Biomarkers: A GRADE-Assessed Systematic Review and Updated Meta-Analysis of Randomized Controlled Trials

SCOPE

Coenzyme Q10 (CoQ10) has become a popular nutritional supplement due to its wide range of beneficial biological effects. Previous meta-analyses show that the attenuation of CoQ10 on inflammatory biomarkers remains controversial. This meta-analysis aims to assess the efficacy and optimal dose of CoQ10 supplementation on inflammatory indicators in the general population.

METHODS AND RESULTS

Databases are searched up to December 2022 resulting in 6713 articles, of which 31 are retrieved for full-text assessment and included 1517 subjects. Double-blind randomized controlled trials (RCTs) of CoQ10 supplementation are eligible if they contain C reactive protein (CRP), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α). CoQ10 supplementation can significantly reduce the levels of circulating CRP (SMD: -0.40, 95% CI: [-0.67 to -0.13], p = 0.003), IL-6 (SMD: -0.67, 95% CI: [-1.01 to -0.33], p < 0.001), and TNF-α (SMD: -1.06, 95% CI: [-1.59 to -0.52], p < 0.001) and increase the concentration of circulating CoQ10.

CONCLUSION

This meta-analysis provides evidence for CoQ10 supplementation to reduce the level of inflammatory mediators in the general population and proposes that daily supplementation of 300-400 mg CoQ10 show superior inhibition of inflammatory factors.

A randomized controlled trial on the coloprotective effect of coenzyme Q10 on immune-inflammatory cytokines, oxidative status, antimicrobial peptides, and microRNA-146a expression in patients with mild-to-moderate ulcerative colitis

PURPOSE

Coenzyme Q10 (CoQ10), having potent antioxidant and anti-inflammatory pharmacological properties, has recently been shown to be a safe and promising agent in maintaining remission of ulcerative colitis (UC). This trial was, therefore, designed to determine CoQ10 efficacy on inflammation and antioxidant status, antimicrobial peptides, and microRNA-146a expression in UC patients.

METHODS

In this randomized double-blind controlled trial, 88 mild-to-moderate UC patients were randomly allocated to receive CoQ10 (200 mg/day) or placebo (rice flour) for 2 months. At the baseline and at an 8-week follow-up, serum levels of Nrf2, cathelicidin LL-37, β-defensin 2, IL-10, IL-17, NF-κB p65 activity in peripheral blood mononuclear cells (PBMCs), simple clinical colitis activity index questionnaire (SCCAIQ), and quality of life (IBDQ-32 score), as well as an expression rate of microRNA-146a were measured.

RESULTS

A significant reduction was detected in the serum IL-17 level, activity of NF-κB p65 in PBMCs, and also SCCAI score in the CoQ10 group compared to the placebo group, whereas IL-10 serum concentrations and IBDQ-32 score of the CoQ10 group considerably increased versus the control group; the changes of these variables were also significantly different within and between groups at the end of the study. Furthermore, CoQ10 remarkably increased serum levels of cathelicidin LL-37. A significant change in serum cathelicidin LL-37 levels was also observed between the two groups. No statistical difference, however, was seen between the two groups in terms of the serum levels of Nrf2 and β-defensin 2 and the relative expression of microRNA-146a.

CONCLUSIONS

Our results indicate that CoQ10 supplementation, along with drug therapy, appears to be an efficient reducer of inflammation in patients with mild-to-moderate UC at a remission phase.

TRIAL REGISTRATION

The research has also been registered at the Iranian Registry of Clinical Trials (IRCT): IRCT20090822002365N17.

The Effect of Coenzyme Q10 Supplementation on Vascular Endothelial Growth Factor and Serum Levels of Interleukin 6 and 8 in Women with Breast Cancer: A Double-Blind, Placebo-Controlled, Randomized Clinical Trial

Background

To better evaluate the efficacy of CoQ10 on the inflammatory markers in breast cancer patients, we conducted a clinical study of patients with breast cancer undergoing tamoxifen therapy. CoQ10 serves as an antioxidant and inhibits oxidation caused by reactive oxygen species. The aim of the current study was to assess the effect of coenzyme Q10 supplementation on serum levels of interleukin 6, 8, and vascular endothelial growth factor (VEGF) in patients with breast cancer undergoing tamoxifen therapy by a double-blind, placebo-controlled, randomized clinical trial.

Methods

In the study, 30 breast cancer patients and 29 healthy subjects were randomized into four groups. Two groups of intervention received 100 mg CoQ10, and two control groups took placebo once a day for 2 months. Blood draws were obtained at baseline and at the end of the study. Serum levels of IL-6, IL-8 and VEGF were analyzed using ELISA kits.

Results

The data of the 59 participants were analyzed. Supplementation with CoQ10 demonstrated a significant decrease in IL-8 and IL-6 serum levels compared to placebo (P< 0.05). Although the downward trend was evident, CoQ10 supplementation did not reveal any significant effect on serum VEGF concentration. The group of patients who received supplements showed the most reduction in serum levels of cytokines among other groups.

Conclusion

CoQ10 supplementation could be effective in ameliorating inflammatory cytokine levels, thereby reducing the consequences of inflammation caused by breast cancer. To generalize the results, larger and longer intervention studies with higher safe doses are needed and should take account of possible costs and harms as well as benefits (registration number: IRCT2015042021874N1).

MicroRNA-21 abrogates palmitate-induced cardiomyocyte apoptosis through caspase-3/NF-κB signal pathways

Objective:

The aim of the study was to investigate the role of microRNA-21 (miR-21) in cardiomyocyte apoptosis and to determine a possible mechanism.

Methods:

H9c2 embryonic rat heart-derived cells were used in the study. Cell viability was determined using the 3-(4.5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay, and flow cytometry was used to evaluate cell apoptosis. Reverse transcription-polymerase chain reaction and western blot assays were used to detect mRNA and protein expression of the apoptosis-related proteins and miR-21. ELISA was used to detect reactive oxygen species (ROS).

Results:

Palmitate exposure greatly reduced miR-21 expression in cardiomyocytes. Apoptosis increased when miR-21 was inhibited with or without palmitate exposure. Consistently, reduced apoptosis was observed when miR-21 was overexpressed in cardiomyocytes. Caspase-3 activity was reduced after palmitate exposure. Bcl-2 protein expression was increased in H9c2 cells when transfected with the miR-21 mimic. MiR-21 overexpression alone did not induce ROS or DNA fragmentation; however, in conjunction with palmitate exposure, miR-21 mimic reduced ROS and DNA fragmentation. Moreover, palmitate administration overcame the antioxidant effect of 3 mM N-acetylcysteine to significantly inhibit apoptosis, DNA fragmentation, and caspase-3 activity. The exposure to palmitate greatly reduced p65 and p-p38 expression in the nucleus. A p38 inhibitor had no effect on the expression of Bcl-2 and cleaved caspase-3 in H9c2 cells alone; however, when combined with exposure to palmitate the p38 inhibitor induced Bcl-2 expression and inhibited caspase-3 activity. The p38 inhibitor by itself did not induce apoptosis, ROS production, or DNA fragmentation in H9c2 cells, but when palmitate was included with the p38 inhibitor, apoptosis, ROS production, and DNA fragmentation were reduced.

Conclusion:

miR-21 protects cardiomyocytes from apoptosis that is induced by palmitate through the caspase-3/NF-κB signal pathways.

Dietary compounds have potential in controlling atherosclerosis by modulating macrophage cholesterol metabolism and inflammation via miRNA

Atherosclerosis (AS) is a typical example of a widespread fatal cardiovascular disease. Accumulation of cholesterol-laden macrophages in the artery wall forms the starting point of AS. Increased influx of oxidized low-density lipoprotein to macrophages and decreased efflux of free cholesterol out of macrophages constitute major factors promoting the development of AS. Inflammation further aggravates the development of AS along or via interaction with the cholesterol metabolism. Many microRNAs (miRNAs) are related to the regulation of macrophage in AS in aspects of cholesterol metabolism and inflammation signaling. Dietary compounds perform AS inhibitory effects via miRNAs in the cholesterol metabolism (miR-19b, miR-378, miR-10b, miR-33a, and miR-33b) and two miRNAs in the inflammation signaling (miR-155 and miR-146a). The targeted miRNAs in the cholesterol metabolism vary greatly among different food compounds; however, in inflammation signaling, most food compounds target miR-155. Many receptors are involved in macrophages via miRNAs, including ABCA1 and ABCG1 as major receptors in the cholesterol metabolism, while nuclear factor-κB (NF-κB) and Nrf2 signaling and PI3K/AKT signaling pathways are targeted during inflammation. This article reviews current literature to investigate possible AS therapy with dietary compounds via targeting miRNAs. Currently existing problems were also discussed to guide further studies.

MicroRNAs as Potential Regulators of Glutathione Peroxidases Expression and Their Role in Obesity and Related Pathologies

Glutathione peroxidases (GPxs) belong to the eight-member family of phylogenetically related enzymes with different cellular localization, but distinct antioxidant function. Several GPxs are important selenoproteins. Dysregulated GPx expression is connected with severe pathologies, including obesity and diabetes. We performed a comprehensive bioinformatic analysis using the programs miRDB, miRanda, TargetScan, and Diana in the search for hypothetical microRNAs targeting 3′untranslated regions (3´UTR) of GPxs. We cross-referenced the literature for possible intersections between our results and available reports on identified microRNAs, with a special focus on the microRNAs related to oxidative stress, obesity, and related pathologies. We identified many microRNAs with an association with oxidative stress and obesity as putative regulators of GPxs. In particular, miR-185-5p was predicted by a larger number of programs to target six GPxs and thus could play the role as their master regulator. This microRNA was altered by selenium deficiency and can play a role as a feedback control of selenoproteins’ expression. Through the bioinformatics analysis we revealed the potential connection of microRNAs, GPxs, obesity, and other redox imbalance related diseases.

The Combination of Physical Exercise with Muscle-Directed Antioxidants to Counteract Sarcopenia: A Biomedical Rationale for Pleiotropic Treatment with Creatine and Coenzyme Q10

Sarcopenia represents an increasing public health risk due to the rapid aging of the world's population. It is characterized by both low muscle mass and function and is associated with mobility disorders, increased risk of falls and fractures, loss of independence, disabilities, and increased risk of death. Despite the urgency of the problem, the development of treatments for sarcopenia has lagged. Increased reactive oxygen species (ROS) production and decreased antioxidant (AO) defences seem to be important factors contributing to muscle impairment. Studies have been conducted to verify whether physical exercise and/or AOs could prevent and/or delay sarcopenia through a normalization of the etiologically relevant ROS imbalance. Despite the strong rationale, the results obtained were contradictory, particularly with regard to the effects of the tested AOs. A possible explanation might be that not all the agents included in the general heading of "AOs" could fulfill the requisites to counteract the complex series of events causing/accelerating sarcopenia: the combination of the muscle-directed antioxidants creatine and coenzyme Q10 with physical exercise as a biomedical rationale for pleiotropic prevention and/or treatment of sarcopenia is discussed.

Paeoniflorin inhibits doxorubicin-induced cardiomyocyte apoptosis by downregulating microRNA-1 expression

Doxorubicin (DOX) is an effective anthracycline anti-tumor antibiotic. Because of its cardiotoxicity, the clinical application of DOX is limited. Paeoniflorin (PEF), a monoterpene glucoside extracted from the dry root of Paeonia, is reported to exert multiple beneficial effects on the cardiovascular system. The present study was designed to explore the protective effect of PEF against DOX-induced cardiomyocyte apoptosis and the underlying mechanism. In cultured H9c2 cells, PEF (100 µmol/l) was added for 2 h prior to exposure to DOX (5 µmol/l) for 24 h. Cell viability, creatine kinase activity, cardiomyocyte apoptosis, intracellular reactive oxygen species (ROS) levels, and the expression of microRNA-1 (miR-1) and B-cell lymphoma 2 (Bcl-2) were measured following treatment with PEF and/or DOX. The results showed that treatment with DOX notably induced cardiomyocyte apoptosis, concomitantly with enhanced ROS generation, upregulated miR-1 expression and downregulated Bcl-2 expression. These effects of DOX were significantly inhibited by pretreatment of the cells with PEF. These results suggest that the inhibitory effect of PEF on DOX-induced cardiomyocyte apoptosis may be associated with downregulation of miR-1 expression via a reduction in ROS generation.

Coenzyme Q regulates the expression of essential genes of the pathogen- and xenobiotic-associated defense pathway in C. elegans

Coenzyme Q (CoQ) is necessary for mitochondrial energy production and modulates the expression of genes that are important for inflammatory processes, growth and detoxification reactions. A cellular surveillance-activated detoxification and defenses (cSADDs) pathway has been recently identified in C. elegans. The down-regulation of the components of the cSADDs pathway initiates an aversion behavior of the nematode. Here we hypothesized that CoQ regulates genes of the cSADDs pathway. To verify this we generated CoQ-deficient worms ("CoQ-free") and performed whole-genome expression profiling. We found about 30% (120 genes) of the cSADDs pathway genes were differentially regulated under CoQ-deficient condition. Remarkably, 83% of these genes were down-regulated. The majority of the CoQ-sensitive cSADDs pathway genes encode for proteins involved in larval development (enrichment score (ES) = 38.0, p = 5.0E(-37)), aminoacyl-tRNA biosynthesis, proteasome function (ES 8.2, p = 5.9E(-31)) and mitochondria function (ES 3.4, p = 1.7E(-5)). 67% (80 genes) of these genes are categorized as lethal. Thus it is shown for the first time that CoQ regulates a substantial number of essential genes that function in the evolutionary conserved cellular surveillance-activated detoxification and defenses pathway in C. elegans.

MicroRNAs as biomarkers of hepatotoxicity in a randomized placebo-controlled study of simvastatin and ubiquinol supplementation

Statins are potent cholesterol-lowering drugs and are generally well tolerated. Hepatotoxicity is a rare but serious adverse effect of statins; however, its mechanisms are not clear. Coenzyme Q10 deficiency has been suggested, and supplementation of reduced coenzyme Q10 (ubiquinol) has been shown to have hepatoprotective effects. MicroRNAs (miRNAs) are small nucleotides that have been shown to be up-regulated in drug-induced liver injury. We hypothesized that circulating miRNAs may be differentially regulated after simvastatin treatment and by comparing with that of simvastatin and ubiquinol supplementation could potentially uncover signatory miRNA profile for simvastatin-induced liver injury. In this double-blind, prospective, randomized-controlled trial, miRNA profiles and liver enzymes were compared between simvastatin-treated patients, with and without ubiquinol supplementation, over 12 weeks compared to baseline. miRNA expression was further validated in HepG2 liver cell lines by real-time PCR. Changes in miR-192, miR-146a, miR-148a, miR-15a, and miR-21 were positively correlated (p<0.05) with alanine aminotransferase in simvastatin-only treated patients. In ubiquinol supplementation group, alanine aminotransferase and alkaline phosphatase were significantly down-regulated after 12 weeks and changes in miR-15a, miR-21 and miR-33a were negatively correlated with alkaline phosphatase (p < 0.05). Bioinformatics analyses predicted that miRNA regulation in simvastatin group was related to reduce proliferation and adenosine triphosphate-binding cassette transporters. Ubiquinol supplementation additionally regulated miRNAs that inhibit apoptotic and inflammatory pathways, suggesting potential hepatoprotective effects. Our results suggest that 20 mg/day of simvastatin does not have significant risk of hepatotoxicity and ubiquinol supplementation may, at the miRNA level, provide potential beneficial changes to reduce the effects of coenzyme Q10 deficiency in the liver.

Bone Components Downregulate Expression of Toll-Like Receptor 4 on the Surface of Human Monocytic U937 Cells: A Cell Model for Postfracture Immune Dysfunction

To mimic the immune status of monocyte in the localized fracture region, toll-like receptor 4 (TLR4) surface expression in human monocytic U937 cells was used as the main target to assess immune dysfunction following bone component exposure. We first identified the effects of bone components (including the marrow content) on TLR4 surface expression and then examined the mechanisms underlying the changes. The level of microRNA-146a expression, an indicator of endotoxin tolerance, was also assayed. Bone component exposure downregulated TLR4 surface expression at 24 h by flow cytometry analysis, compatible with the result obtained from the membranous portion of TLR4 by western blot analysis. The cytoplasmic portion of TLR4 paradoxically increased after bone component exposure. Impaired TLR4 trafficking from the cytoplasm to the membrane was related to gp96 downregulation, as observed by western blot analysis, and this was further evidenced by gp96-TLR4 colocalization under confocal microscopy. TaqMan analysis revealed that the expression of microRNA-146a was also upregulated. This cell model demonstrated that bone component exposure downregulated TLR4 surface expression in a gp96-related manner in human monocytic U937 cells, an indicator of immunosuppression at 24 h. Immune dysfunction was further evidenced by upregulation of microRNA-146a expression at the same time point.

Determination of the coenzyme Q10 status in a large Caucasian study population

Coenzyme Q10 (CoQ10 ) exists in a reduced (ubiquinol) and an oxidized (ubiquinone) form in all human tissues and functions, amongst others, in the respiratory chain, redox-cycles, and gene expression. As the status of CoQ10 is an important risk factor for several diseases, here we determined the CoQ10 status (ubiquinol, ubiquinone) in a large Caucasian study population (n = 1,911). The study population covers a wide age range (age: 18-83 years, 43.4% men), has information available on more than 10 measured clinical phenotypes, more than 30 diseases (presence vs. absence), about 30 biomarkers, and comprehensive genetic information including whole-genome SNP typing (>891,000 SNPs). The major aim of this long-term resource in CoQ10 research is the comprehensive analysis of the CoQ10 status with respect to integrated health parameters (i.e., fat metabolism, inflammation), disease-related biomarkers (i.e., liver enzymes, marker for heart failure), common diseases (i.e., neuropathy, myocardial infarction), and genetic risk in humans. Based on disease status, biomarkers, and genetic variants, our cohort is also useful to perform Mendelian randomisation approaches. In conclusion, the present study population is a promising resource to gain deeper insight into CoQ10 status in human health and disease.

Coenzyme Q10 promotes macrophage cholesterol efflux by regulation of the activator protein-1/miR-378/ATP-binding cassette transporter G1-signaling pathway

OBJECTIVE

Recent studies have shown the role of miRNAs in macrophage reverse cholesterol transport and atherogenesis. We hypothesized that coenzyme Q10 (CoQ10) may increase macrophage reverse cholesterol transport by regulating miRNA expression that contributes to the prevention of atherosclerosis.

APPROACH AND RESULTS

CoQ10 treatment suppressed oxidized low-density lipoprotein-induced macrophage foam cell formation by ameliorating the binding of activator protein-1 to the putative promoter region of miR-378 primary transcript, thus decreasing the miR-378 level and enhancing the ATP-binding cassette transporter G1-mediated macrophage cholesterol efflux to high-density lipoprotein. Subsequently, the axis of activator protein-1/miR-378/ATP-binding cassette transporter G1 cholesterol efflux was confirmed in peritoneal macrophages isolated from CoQ10-treated apolipoprotein E-deficient mice. Finally, CoQ10 consumption promoted macrophage reverse cholesterol transport and inhibited the progression of atherosclerosis in apolipoprotein E-deficient mice.

CONCLUSIONS

This study identified activator protein-1/miR-378/ATP-binding cassette transporter G1 as a novel cascade for CoQ10 in facilitating macrophage cholesterol efflux in vitro and in vivo. Our data thus imply that both CoQ10 and miR-378 are promising candidates for atherosclerosis prevention and treatment.

MicroRNAs as Haematopoiesis Regulators

The production of different types of blood cells including their formation, development, and differentiation is collectively known as haematopoiesis. Blood cells are divided into three lineages erythriod (erythrocytes), lymphoid (B and T cells), and myeloid (granulocytes, megakaryocytes, and macrophages). Haematopoiesis is a complex process regulated by several mechanisms including microRNAs (miRNAs). miRNAs are small RNAs which regulate the expression of a number of genes involved in commitment and differentiation of hematopoietic stem cells. Evidence shows that miRNAs play an important role in haematopoiesis; for example, myeloid and erythroid differentiation is blocked by the overexpression of miR-15a. miR-221, miR-222, and miR-24 inhibit the erythropoiesis, whereas miR-150 plays a role in B and T cell differentiation. miR-146 and miR-10a are downregulated in megakaryopoiesis. Aberrant expression of miRNAs was observed in hematological malignancies including chronic myelogenous leukemia, chronic lymphocytic leukemia, multiple myelomas, and B cell lymphomas. In this review we have focused on discussing the role of miRNA in haematopoiesis.

Ubiquinol supplementation protects against renal ischemia and reperfusion injury in rats

Generation of toxic oxygen metabolites followed by oxidant- and inflammatory-mediated tissue injury plays a crucial role in the pathogenesis of ischemia and reperfusion (IR). Ubiquinol, the reduced form of coenzyme Q10, is recognized for its potent antioxidant and anti-inflammatory properties in biological membranes. The present study was established to examine the possible protective effect of ubiquinol against renal IR injury. Groups of male Wistar rats were assigned into sham, ubiquinol, IR (45-min bilateral renal ischemia followed by 24-h reperfusion), and ubiquinol+ IR (ubiquinol 300 mg/kg given orally for 7 consecutive days before IR induction). Renal morphology, function, oxidative stress, and inflammatory markers were evaluated at the end of reperfusion. IR caused renal dysfunction as shown by significant increases in blood urea nitrogen, plasma creatinine, and a decrease in creatinine clearance. Light and electron microscopic examinations exhibited severe tubular damages and abnormal mitochondrial structure. IR-induced renal injuries were associated with significant increases in malondialdehyde, nitric oxide, tumor necrosis factor-α, but decreases in antioxidant thiols and superoxide dismutase. Pretreatment with ubiquinol obviously attenuated all the changes caused by IR, whereas it had no considerable effect in the sham-operated rats. These findings indicate that supplementation of ubiquinol prior to IR incidence confers functional and morphological protection to the ischemic kidney by maintaining the redox balance and regulating the generation of inflammatory mediator. The outcomes suggest that ubiquinol may be a potential candidate to counteract organ dysfunction in conditions involving IR injury.

Anti-inflammatory effect of ubiquinol-10 on young and senescent endothelial cells via miR-146a modulation

Clinical evidence demonstrates that ubiquinol-10, the reduced active form of coenzyme Q10 (CoQ10H₂), improves endothelial function through its antioxidant and probably its anti-inflammatory properties. We previously reported that a biomarker combination including miR-146a, its target protein IL-1 receptor-associated kinase (IRAK-1), and released interleukin (IL)-6, here collectively designated as MIRAKIL, indicates senescence-associated secretory phenotype (SASP) acquisition by primary human umbilical vein endothelial cells (HUVECs). We explore the ability of short- and long-term CoQ10H₂ supplementation to affect MIRAKIL in HUVECs, used as a model of vascular aging, during replicative senescence in the absence/presence of lipopolysaccharide (LPS), a proinflammatory stimulus. Senescent HUVECs had the same ability as young cells to internalize CoQ10 and exhibit an improved oxidative status. LPS-induced NF-κB activation diminished after CoQ10H₂ pretreatment in both young and senescent cells. However, short-term CoQ10H₂ supplementation attenuated LPS-induced MIRAKIL changes in young cells; in senescent cells CoQ10H₂ supplementation significantly attenuated LPS-induced miR-146a and IRAK-1 modulation but failed to curb IL-6 release. Similar results were obtained with long-term CoQ10H₂ incubation. These findings provide new insights into the molecular mechanisms by which CoQ10H₂ stems endothelial cell inflammatory responses and delays SASP acquisition. These phenomena may play a role in preventing the endothelial dysfunction associated with major age-related diseases.

The emerging role of MicroRNAs in the regulation of gene expression by nutrients

MicroRNAs (miRNAs) are a class of evolutionarily conserved, small non-coding RNAs of 19-24 nucleotides in length that regulate gene expression mostly at the posttranscriptional level. They are known to be involved in the control of different processes such as cell cycling, programmed cell death, cell differentiation, tumor development, metastasis, and sensing of nutrient stress. This review summarizes the evidence regarding the changes in miRNA expression that are caused by diets with a deficiency or augmented intake of nutrients such as amino acids, carbohydrates, fatty acids, vitamins, and phytochemicals. As diet is known to influence the expression of miRNAs, miRNA profiling has the potential to be useful in the assessment of nutritional status in dietary intervention studies. Additionally, as it can change miRNA expression, diet may be used as a therapeutic agent to treat many different diseases. Also, we explored here some ideas on therapeutics based on the manipulation of miRNA expression levels for dietary-derived diseases as well as the putative effect of food-derived miRNAs on host gene expression.

Ubiquinol decreases monocytic expression and DNA methylation of the pro-inflammatory chemokine ligand 2 gene in humans

BACKGROUND

Coenzyme Q₁₀ is an essential cofactor in the respiratory chain and serves in its reduced form, ubiquinol, as a potent antioxidant. Studies in vitro and in vivo provide evidence that ubiquinol reduces inflammatory processes via gene expression. Here we investigate the putative link between expression and DNA methylation of ubiquinol sensitive genes in monocytes obtained from human volunteers supplemented with 150 mg/ day ubiquinol for 14 days.

FINDINGS

Ubiquinol decreases the expression of the pro-inflammatory chemokine (C-X-C motif) ligand 2 gene (CXCL2) more than 10-fold. Bisulfite-/ MALDI-TOF-based analysis of regulatory regions of the CXCL2 gene identified six adjacent CpG islands which showed a 3.4-fold decrease of methylation status after ubiquinol supplementation. This effect seems to be rather gene specific, because ubiquinol reduced the expression of two other pro-inflammatory genes (PMAIP1, MMD) without changing the methylation pattern of the respective gene.

CONCLUSION

In conclusion, ubiquinol decreases monocytic expression and DNA methylation of the pro-inflammatory CXCL2 gene in humans. Current Controlled Trials ISRCTN26780329.

Is there a place for coenzyme Q in the management of metabolic disorders associated with obesity?

Coenzyme Q (CoQ), a lipophilic cofactor of the electron transport chain in the mitochondria, can be synthesized endogenously or provided by food. The aim of this review is to summarize the in vitro cell culture studies, the in vivo animal studies, and the human studies investigating the impact of CoQ supplementation on the occurrence of obesity and related disorders (diabetes, hypertension, lipemia, and atherosclerosis). The antioxidative properties of CoQ have been observed in different experimental models of atherosclerosis, obesity, and diabetes. The recent discovery of the anti-inflammatory effect of CoQ, mostly described in vitro, has generated increased interest in CoQ supplementation, but it needs to be confirmed in vivo in pathological situations. CoQ intervention studies in humans failed to show reproducible effects on body weight, fat mass, or glycemia, but CoQ supplementation does seem to have an antihypertensive effect. The molecular mechanism to explain this effect has only recently been discovered.

New developments on the functions of coenzyme Q in mitochondria

The notion of a mobile pool of coenzyme Q (CoQ) in the lipid bilayer has changed with the discovery of respiratory supramolecular units, in particular the supercomplex comprising complexes I and III; in this model, the electron transfer is thought to be mediated by tunneling or microdiffusion, with a clear kinetic advantage on the transfer based on random collisions. The CoQ pool, however, has a fundamental function in establishing a dissociation equilibrium with bound quinone, besides being required for electron transfer from other dehydrogenases to complex III. The mechanism of CoQ reduction by complex I is analyzed regarding recent developments on the crystallographic structure of the enzyme, also in relation to the capacity of complex I to generate superoxide. Although the mechanism of the Q-cycle is well established for complex III, involvement of CoQ in proton translocation by complex I is still debated. Some additional roles of CoQ are also examined, such as the antioxidant effect of its reduced form and the capacity to bind the permeability transition pore and the mitochondrial uncoupling proteins. Finally, a working hypothesis is advanced on the establishment of a vicious circle of oxidative stress and supercomplex disorganization in pathological states, as in neurodegeneration and cancer.

Therapeutic use of coenzyme Q10 and coenzyme Q10-related compounds and formulations

IMPORTANCE OF THE FIELD

Coenzyme Q(10) (CoQ(10)) is found in blood and in all organs. CoQ(10) deficiencies are due to autosomal recessive mutations, ageing-related oxidative stress and carcinogenesis processes, and also statin treatment. Many neurodegenerative disorders, diabetes, cancer and muscular and cardiovascular diseases have been associated with low CoQ(10) levels, as well as different ataxias and encephalomyopathies.

AREAS COVERED IN THIS REVIEW

We review the efficacy of a variety of commercial formulations which have been developed to solubilise CoQ(10) and promote its better absorption in vivo, and its use in the therapy of pathologies associated with low CoQ(10) levels, with emphasis in the results of the clinical trials. Also, we review the use of its analogues idebenone and MitoQ.

WHAT THE READER WILL GAIN

This review covers the most relevant aspects related with the therapeutic use of CoQ(10), including existing formulations and their effects on its bioavailability.

TAKE HOME MESSAGE

CoQ(10) does not cause serious adverse effects in humans and new formulations have been developed that increase CoQ(10) absorption. Oral CoQ(10) is a viable antioxidant strategy in many diseases, providing a significant to mild symptomatic benefit. Idebenone and MitoQ are promising substitutive CoQ(10)-related drugs which are well tolerated and safe.

Supplementation with the reduced form of Coenzyme Q10 decelerates phenotypic characteristics of senescence and induces a peroxisome proliferator-activated receptor-alpha gene expression signature in SAMP1 mice

Our present study reveals significant decelerating effects on senescence processes in middle-aged SAMP1 mice supplemented for 6 or 14 months with the reduced form (Q(10)H(2), 500 mg/kg BW/day) of coenzyme Q(10) (CoQ(10)). To unravel molecular mechanisms of these CoQ(10) effects, a genome-wide transcript profiling in liver, heart, brain and kidney of SAMP1 mice supplemented with the reduced (Q(10)H(2)) or oxidized form of CoQ(10) (Q(10)) was performed. Liver seems to be the main target tissue of CoQ(10) intervention, followed by kidney, heart and brain. Stringent evaluation of the resulting data revealed that Q(10)H(2) has a stronger impact on gene expression than Q(10), primarily due to differences in the bioavailability. Indeed, Q(10)H(2) supplementation was more effective than Q(10) to increase levels of CoQ(10) in the liver of SAMP1 mice. To identify functional and regulatory connections of the "top 50" (p<0.05) Q(10)H(2)-sensitive transcripts in liver, text mining analysis was used. Hereby, we identified Q(10)H(2)-sensitive genes which are regulated by peroxisome proliferator-activated receptor-alpha and are primarily involved in cholesterol synthesis (e.g. HMGCS1, HMGCL and HMGCR), fat assimilation (FABP5), lipoprotein metabolism (PLTP) and inflammation (STAT-1). These data may explain, at least in part, the decelerating effects on degenerative processes observed in Q(10)H(2)-supplemented SAMP1 mice.

Exposure to metal-rich particulate matter modifies the expression of candidate microRNAs in peripheral blood leukocytes

BACKGROUND

Altered patterns of gene expression mediate the effects of particulate matter (PM) on human health, but mechanisms through which PM modifies gene expression are largely undetermined. MicroRNAs (miRNAs) are highly conserved, noncoding small RNAs that regulate the expression of broad gene networks at the posttranscriptional level.

OBJECTIVES

We evaluated the effects of exposure to PM and PM metal components on candidate miRNAs (miR-222, miR-21, and miR-146a) related with oxidative stress and inflammatory processes in 63 workers at an electric-furnace steel plant.

METHODS

We measured miR-222, miR-21, and miR-146a expression in blood leukocyte RNA on the first day of a workweek (baseline) and after 3 days of work (postexposure). Relative expression of miRNAs was measured by real-time polymerase chain reaction. We measured blood oxidative stress (8-hydroxyguanine) and estimated individual exposures to PM1 (< 1 microm in aerodynamic diameter), PM10 (< 10 microm in aerodynamic diameter), coarse PM (PM10 minus PM1), and PM metal components (chromium, lead, cadmium, arsenic, nickel, manganese) between the baseline and postexposure measurements.

RESULTS

Expression of miR-222 and miR-21 (using the 2-DeltaDeltaCT method) was significantly increased in postexposure samples (miR-222: baseline = 0.68 +/- 3.41, postexposure = 2.16 +/- 2.25, p = 0.002; miR-21: baseline = 4.10 +/- 3.04, postexposure = 4.66 +/- 2.63, p = 0.05). In postexposure samples, miR-222 expression was positively correlated with lead exposure (beta = 0.41, p = 0.02), whereas miR-21 expression was associated with blood 8-hydroxyguanine (beta = 0.11, p = 0.03) but not with individual PM size fractions or metal components. Postexposure expression of miR-146a was not significantly different from baseline (baseline = 0.61 +/- 2.42, postexposure = 1.90 +/- 3.94, p = 0.19) but was negatively correlated with exposure to lead (beta = -0.51, p = 0.011) and cadmium (beta = -0.42, p = 0.04).

CONCLUSIONS

Changes in miRNA expression may represent a novel mechanism mediating responses to PM and its metal components.

Identification of LPS-inducible genes downregulated by ubiquinone in human THP-1 monocytes

Coenzyme Q(10) (CoQ(10)) is an obligatory element in the respiratory chain and functions as a potent antioxidant of lipid membranes. More recently, anti-inflammatory effects as well as an impact of CoQ(10) on gene expression have been observed. To reveal putative effects of Q(10) on LPS-induced gene expression, whole genome expression analysis was performed in the monocytic cell line THP-1. Thousand one hundred twenty-nine and 710 probe sets have been identified to be significantly (P <or= 0.05) up and downregulated in LPS-treated cells when compared with controls, respectively. Text mining analysis of the top 50 LPS upregulated genes revealed a functional connection in the NFkappaB pathway and confirmed our applied in vitro stimulation model. Moreover, 33 LPS-sensitive genes have been identified to be significantly downregulated by Q(10)-treatment between a factor of 1.32 and 1.85. GeneOntology (GO) analysis revealed for the Q(10)-sensitve genes a primary involvement in protein metabolism (e.g., HERC1 and EPS15), cell proliferation (e.g., CCDC100 and SMURF1), and transcriptional processes (e.g., CNOT4 and STK4). Three genes were either related to NFkappaB transcription factor activity (ERC1), cytokinesis (DIAPH2), or modulation of oxidative stress (MSRA). In conclusion, our data provide evidence that Q(10) downregulates LPS-inducible genes in the monocytic cell line THP-1. Thus, the previously described effects of Q(10) on the reduction of proinflammatory mediators might be due to its antioxidant impact on gene expression.