Diterpenoid honatisine overcomes temozolomide resistance in glioblastoma by inducing mitonuclear protein imbalance through disruption of TFAM-mediated mtDNA transcription.

BACKGROUND: Glioblastoma (GBM) represents as the most formidable intracranial malignancy. The systematic exploration of natural compounds for their potential applications in GBM therapy has emerged as a pivotal and fruitful avenue of research. PURPOSE: In the present study, a panel of 96 diterpenoids was systematically evaluated as a repository of potential antitumour agents. The primary objective was to discern their potency in overcoming resistance to temozolomide (TMZ). Through an extensive screening process, honatisine, a heptacyclic diterpenoid alkaloid, emerged as the most robust candidate. Notably, honatisine exhibited remarkable efficacy in patient-derived primary and recurrent GBM strains. Subsequently, we subjected this compound to comprehensive scrutiny, encompassing GBM cultured spheres, GBM organoids (GBOs), TMZ-resistant GBM cell lines, and orthotopic xenograft mouse models of GBM cells. RESULTS: Our investigative efforts delved into the mechanistic underpinnings of honatisine's impact. It was discerned that honatisine prompted mitonuclear protein imbalance and elicited the mitochondrial unfolded protein response (UPRmt). This effect was mediated through the selective depletion of mitochondrial DNA (mtDNA)-encoded subunits, with a particular emphasis on the diminution of mitochondrial transcription factor A (TFAM). The ultimate outcome was the instigation of deleterious mitochondrial dysfunction, culminating in apoptosis. Molecular docking and surface plasmon resonance (SPR) experiments validated honatisine's binding affinity to TFAM within its HMG-box B domain. This binding may promote phosphorylation of TFAM and obstruct the interaction of TFAM bound to heavy strand promoter 1 (HSP1), thereby enhancing Lon-mediated TFAM degradation. Finally, in vivo experiments confirmed honatisine's antiglioma properties. Our comprehensive toxicological assessments underscored its mild toxicity profile, emphasizing the necessity for a thorough evaluation of honatisine as a novel antiglioma agent. CONCLUSION: In summary, our data provide new insights into the therapeutic mechanisms underlying honatisine's selective inducetion of apoptosis and its ability to overcome chemotherapy resistance in GBM. These actions are mediated through the disruption of mitochondrial proteostasis and function, achieved by the inhibition of TFAM-mediated mtDNA transcription. This study highlights honatisine's potential as a promising agent for glioblastoma therapy, underscoring the need for further exploration and investigation.

Mitochondrial Function Are Disturbed in the Presence of the Anticancer Drug, 3-Bromopyruvate.

3-bromopuryvate (3-BP) is a compound with unique antitumor activity. It has a selective action against tumor cells that exhibit the Warburg effect. It has been proven that the action of 3-BP is pleiotropic: it acts on proteins, glycolytic enzymes, reduces the amount of ATP, induces the formation of ROS (reactive oxygen species), and induces nuclear DNA damage. Mitochondria are important organelles for the proper functioning of the cell. The production of cellular energy (ATP), the proper functioning of the respiratory chain, or participation in the production of amino acids are one of the many functions of mitochondria. Here, for the first time, we show on the yeast model that 3-BP acts in the eukaryotic cell also by influence on mitochondria and that agents inhibiting mitochondrial function can potentially be used in cancer therapy with 3-BP. We show that cells with functional mitochondria are more resistant to 3-BP than rho0 cells. Using an MTT assay (a colorimetric assay for assessing cell metabolic activity), we demonstrated that 3-BP decreased mitochondrial activity in yeast in a dose-dependent manner. 3-BP induces mitochondrial-dependent ROS generation which results in ∆sod2, ∆por1, or ∆gpx1 mutant sensitivity to 3-BP. Probably due to ROS mtDNA lesions rise during 3-BP treatment. Our findings may have a significant impact on the therapy with 3-BP.

Daily Oral Supplementation with 60 mg of Elemental Iron for 12 Weeks Alters Blood Mitochondrial DNA Content, but Not Leukocyte Telomere Length in Cambodian Women.

There is limited evidence regarding the potential risk of untargeted iron supplementation, especially among individuals who are iron-replete or have genetic hemoglobinopathies. Excess iron exposure can increase the production of reactive oxygen species, which can lead to cellular damage. We evaluated the effect of daily oral supplementation on relative leukocyte telomere length (rLTL) and blood mitochondrial DNA (mtDNA) content in non-pregnant Cambodian women (18-45 years) who received 60 mg of elemental iron as ferrous sulfate (n = 190) or a placebo (n = 186) for 12 weeks. Buffy coat rLTL and mtDNA content were quantified by monochrome multiplex quantitative polymerase chain reaction. Generalized linear mixed-effects models were used to predict the absolute and percent change in rLTL and mtDNA content after 12 weeks. Iron supplementation was not associated with an absolute or percent change in rLTL after 12 weeks compared with placebo (ß-coefficient: -0.04 [95% CI: -0.16, 0.08]; p = 0.50 and ß-coefficient: -0.96 [95% CI: -2.69, 0.77]; p = 0.28, respectively). However, iron supplementation was associated with a smaller absolute and percent increase in mtDNA content after 12 weeks compared with placebo (ß-coefficient: -11 [95% CI: -20, -2]; p = 0.02 and ß-coefficient: -11 [95% CI: -20, -1]; p= 0.02, respectively). Thus, daily oral iron supplementation for 12 weeks was associated with altered mitochondrial homeostasis in our study sample. More research is needed to understand the risk of iron exposure and the biological consequences of altered mitochondrial homeostasis in order to inform the safety of the current global supplementation policy.

Distinct Epigenetic Reprogramming, Mitochondrial Patterns, Cellular Morphology, and Cytotoxicity after Bee Venom Treatment.

BACKGROUND: Bee venom is a promising agent for cancer treatment due to its selective cytotoxic potential for cancer cells through apoptotic pathways. However, there is no evidence for changes in the epigenome and mitochondrial DNA copy numbers after bee venom application. The purpose of this study was to determine the impact of bee venom on cytosine modifications and mitochondrial DNA copy number variation. METHODS: A broad range of methods was applied to elucidate the impact of bee venom on neoplastic cells. These included MTT assay for detection of cytotoxicity, immunostaining of cytosine modifications and mitochondria, assessment of cellular morphology by flow cytometry, and quantification of mitochondrial DNA copy numbers using QPCR. RESULTS: Bee venom-induced cell death was selective for cancer cells, where it triggered a response characterized by alteration of cytosine modification. In contrast, normal cells were more resistant to DNA modifications. Furthermore, application of the venom resulted in variation of mitochondrial membrane permeability and mitochondrial DNA copy numbers, together with alterations in cell morphology, manifesting as reduced affected cell size. CONCLUSION: The study findings suggest that bee venom can be used as a selective DNA (de)methylating agent in cancer. Various agents (such as decitabine and 5-azacytidine) have been synthesized and developed for cancer treatment, and a range of syntheses and preparation and application methods have been described for these patented drugs. However, to the best of our knowledge, no previous research has investigated the use of bee venom or any component thereof for epigenetic therapy in cancer cells.

L-Arginine Reduces Nitro-Oxidative Stress in Cultured Cells with Mitochondrial Deficiency.

L-Arginine (L-ARG) supplementation has been suggested as a therapeutic option in several diseases, including Mitochondrial Encephalomyopathy, Lactic Acidosis, and Stroke-like syndrome (MELAS), arguably the most common mitochondrial disease. It is suggested that L-ARG, a nitric oxide (NO) precursor, can restore NO levels in blood vessels, improving cerebral blood flow. However, NO also participates in mitochondrial processes, such as mitochondrial biogenesis, the regulation of the respiratory chain, and oxidative stress. This study investigated the effects of L-ARG on mitochondrial function, nitric oxide synthesis, and nitro-oxidative stress in cell lines harboring the MELAS mitochondrial DNA (mtDNA) mutation (m.3243A>G). We evaluated mitochondrial enzyme activity, mitochondrial mass, NO concentration, and nitro-oxidative stress. Our results showed that m.3243A>G cells had increased NO levels and protein nitration at basal conditions. Treatment with L-ARG did not affect the mitochondrial function and mass but reduced the intracellular NO concentration and nitrated proteins in m.3243A>G cells. The same treatment led to opposite effects in control cells. In conclusion, we showed that the main effect of L-ARG was on protein nitration. Lowering protein nitration is probably involved in the mechanism related to L-ARG supplementation benefits in MELAS patients.

A Pilot Study on the Effects of l-Carnitine and Trimethylamine-N-Oxide on Platelet Mitochondrial DNA Methylation and CVD Biomarkers in Aged Women.

l-carnitine supplementation has been used for cardiovascular health protection for a long time. Recently, trimethylamine-N-oxide (TMAO), which is an end product of l-carnitine metabolism via the activity of microbiota, has been identified as a cardiovascular disease (CVD) biomarker. The aim of this study was to assess the effect of 6 months of l-carnitine supplementation in a group of aged women engaged in a regular physical training. Platelet mitochondrial DNA methylation, an emerging and innovative biomarker, lipid profile and TMAO levels have been measured. TMAO increased after l-carnitine supplementation (before 344.3 ± 129.8 ng/mL vs. after 2216.8 ± 1869.0 ng/mL; n = 9; paired t-test, p = 0.02). No significant effects on TMAO were exerted by training alone (n = 9) or by l-leucine supplementation (n = 12). TMAO levels after 6 months of l-carnitine supplementation were associated with higher low-density lipoprotein-cholesterol (LDL-c) (Spearman Rho = 0.518, p = 0.003) and total cholesterol (TC) (Spearman Rho = 0.407, p = 0.026) levels. l-carnitine supplementation increased D-loop methylation in platelets (+6.63%; paired t-test, p = 0.005). D-loop methylation was not directly correlated to the TMAO augmentation observed in the supplemented group, but its increase inversely correlated with TC (Pearson coefficient = -0.529, p = 0.029) and LDL-c (Pearson coefficient = -0.439, p = 0.048). This evidence supports the hypothesis that the correlation between l-carnitine, TMAO and atherosclerosis might be more complex than already postulated, and the alteration of mitochondrial DNA (mtDNA) methylation in platelets could be involved in the pathogenesis of this multifactorial disease.

Recombinant Buckwheat Trypsin Inhibitor Improves the Protein and Mitochondria Homeostasis in Caenorhabditis elegans Model of Aging and Age-Related Disease.

BACKGROUND: With the acceleration of aging process in human society, improvements of the physical functionality and life quality in the elderly population are more meaningful than pure longevity. Buckwheat trypsin inhibitor is a low molecular weight polypeptide extracted from buckwheat, which is a beneficial food for improving the health in the elderly. OBJECTIVES: The aim of the current study was to evaluate the potential beneficial effects of recombinant buckwheat trypsin inhibitor (rBTI) on age-dependent function decline and the primary mechanism. METHOD: Day 10 N2 Caenorhabditis elegans and day 6 AM140 C. elegans cultured at 25°C were used as models of aging and age-related disease, respectively. Motor function was as an indicator of age-dependent function. ATP content and damage mitochondrial DNA mass were detected to assess mitochondrial damage and function by ATP Assay Kit and agarose gel electrophoresis, respectively. Soluble protein content was quantified by SDS polyacrylamide gel electrophoresis. Autophagy-related genes transcription levels, autophagy marker proteins lgg-1, and lysosomal content were analyzed to quantify autophagy levels by qRT-PCR, transgenic C. elegans, and lysosomal staining. Autophagy inhibitor chloroquine, daf-16 mutant, and RNA Interference were used to determine the roles of autophagy and DAF-16 in rBTI-mediated effects. RESULTS: In this study, we found that rBTI could decrease the proportions of insoluble protein and impaired mitochondria, finally reduce motility deficits in both models. Further study indicated that rBTI activated the autophagy, and the inhibition of autophagy reduced rBTI-mediated beneficial effects. Genetic analyses showed the transcriptional activity of DAF-16 was increased by rBTI and was required for rBTI-mediated beneficial effects. CONCLUSIONS: These data indicated that rBTI might promote the autophagy to alleviate the age-related functional decline via DAF-16 in C. elegans and suggested a potential role of rBTI as a nutraceutical for the improvement of age-related complications.

N-Acetylcysteine protects against intrauterine growth retardation-induced intestinal injury via restoring redox status and mitochondrial function in neonatal piglets.

PURPOSE: Intrauterine growth retardation (IUGR) is detrimental to the intestinal development of neonates, yet satisfactory treatment strategies remain limited. This study was, therefore, conducted using neonatal piglets as a model to investigate the potential of N-acetylcysteine (NAC) to alleviate intestinal damage caused by IUGR. METHODS: Seven normal birth weight (NBW) and fourteen IUGR neonatal male piglets were selected and then fed a basal milk diet (NBW-CON and IUGR-CON groups) or a basal milk diet supplemented with 1.2 g NAC per kg of diet (IUGR-NAC group) from 7 to 21 days of age (n = 7). Parameters associated with the severity of intestinal injury, villus morphology and ultrastructural structure, redox status, and mitochondrial function were analyzed. RESULTS: Compared with the NBW-CON piglets, the IUGR-CON piglets exhibited decreased villus height and greater numbers of apoptotic cells in jejunum, along with the increases in malondialdehyde and protein carbonyl concentrations and a decreased adenosine triphosphate (ATP) content. Treatment with NAC significantly increased jejunal superoxide dismutase activity, reduced glutathione: oxidized glutathione ratio, and the mRNA abundance of nuclear respiratory factor 2, heme oxygenase 1, and superoxide dismutase 2 in the IUGR-NAC piglets compared with the IUGR-CON piglets. In addition, NAC improved the efficiency of mitochondrial oxidative metabolism and ATP generation, ameliorated mitochondrial swelling, and inhibited the overproduction of mitochondrial superoxide anion in the jejunal mucosa. CONCLUSIONS: Dietary supplementation of NAC shows promise for attenuating the early intestinal injury of young piglets with IUGR, probably through its antioxidant action to restore redox status and mitochondrial function.

Melatonin protects in vitro matured porcine oocytes from toxicity of Aflatoxin B1.

Aflatoxin B1 (AFB1) is a major food and feed contaminant that threaten public health. Previous studies indicate that AFB1 exposure disrupted oocyte maturation. However, an effective and feasible method is unavailable for protecting oocytes against toxicity of AFB1. In the present study, using in vitro matured porcine oocytes and parthenogenetic embryos as model, we confirmed that AFB1 exposure during in vitro oocyte maturation (IVM) significantly impaired both nuclear and cytoplasmic maturation in a dose- and time-dependent manner. The different concentrations of melatonin were also tested for their protective effects on oocytes against the AFB1-induced toxicity. Our results showed that supplementation of a relative high concentration of melatonin (10-3 mol/L) during IVM efficiently reversed the impaired development rate and blastocyst quality, to the levels comparable to those of the control group. Further analysis indicated that melatonin application efficiently alleviated reactive oxygen species accumulation and initiation of apoptosis induced by AFB1 exposure. In addition, disrupted GSH/GPX system, as well as inhibited mitochondrial DNA (mtDNA) replication and mitochondrial biogenesis in AFB1-treated oocytes, can be notably reversed by melatonin application. Furthermore, cumulus cells may be important in mediating the toxicity of AFB1 to oocytes, and the metabolism of AFB1 in cumulus cells can be depressed by melatonin. To the best of our knowledge, this is the first report to confirm that melatonin application can efficiently protect oocytes from AFB1-induced toxicity. Our study provides a promising and practical strategy for alleviating or reversing AFB1-induced female reproductive toxicity in both clinical treatment and domestic reproductive management.

Resveratrol enhances the clearance of mitochondrial damage by vitrification and improves the development of vitrified-warmed bovine embryos.

The present study investigated the vitrification-induced deterioration of mitochondrial functions that may reduce the developmental ability of post-warming bovine embryos. In addition, the effect of supplementation of the culture medium with resveratrol on the mitochondrial functions and post-warming embryonic development was examined. Two days after in vitro fertilization, embryos with 8-12 cells (referred to hereafter as 8-cell embryos) were vitrified and warmed, followed by in vitro incubation for 5 days in a culture medium containing either the vehicle or 0.5 µM resveratrol. Vitrification reduced embryonic development until the blastocyst stage, reduced the ATP content of embryos, and impaired the mitochondrial genome integrity, as determined by real-time polymerase chain reaction. Although the total cell number and mitochondrial DNA copy number (Mt-number) of blastocysts were low in the vitrified embryos, the Mt-number per blastomere was similar among the blastocysts derived from fresh (non-vitrified) and vitrified-warmed embryos. Supplementation of the culture medium with resveratrol enhanced the post-warming embryonic development and reduced the Mt-number and reactive oxygen species level in blastocysts and blastomeres without affecting the ATP content. An increase in the content of cell-free mitochondrial DNA in the spent culture medium was observed following cultivation of embryos with resveratrol. These results suggested that vitrification induces mitochondrial damages and that resveratrol may enhance the development of post-warming embryos and activates the degeneration of damaged mitochondria, as indicated by the increase in the cell-free mitochondrial DNA content in the spent culture medium and the decrease in the Mt-number of blastocysts and blastomeres.

Mitochondrial diseases and status epilepticus.

This narrative review focuses on the pathophysiology, diagnosis, and management of status epilepticus in the context of primary mitochondrial disease. Epilepsy is common in mitochondrial disease, reported in >20% of adult cases and 40%-60% of pediatric cohorts. Status epilepticus is less frequently reported and appears to be associated with particular subgroups of mitochondrial disorders, namely defects of the mitochondrial DNA and its maintenance, and disorders of mitochondrial translation and dynamics. Mechanisms underlying mitochondrial status epilepticus are incompletely understood, and may include bioenergetic failure, oxidative stress, immune dysfunction, and impaired mitochondrial dynamics. Treatments tried in mitochondrial status epilepticus include antiepileptic drugs, anesthetic agents, magnesium, high-dose steroids, immune globulins, vagus nerve stimulation, and surgical procedures, all with variable success. The outcome of mitochondrial status epilepticus is extremely poor, and effective therapeutic options have not been reported. Improved understanding of the mechanisms underpinning mitochondrial status epilepticus is needed in order to develop more effective treatments.

Curcumin attenuates hepatic mitochondrial dysfunction through the maintenance of thiol pool, inhibition of mtDNA damage, and stimulation of the mitochondrial thioredoxin system in heat-stressed broilers.

The aim of this study was to investigate the effects of dietary curcumin supplementation on the performance, mitochondrial redox system, mitochondrial DNA (mtDNA) integrity, and antioxidant-related gene expression in the liver of broiler chickens after heat stress treatment. At day 21, a total of 400 Arbor Acres broiler chickens with similar body weight (BW) were divided into 5 groups with 8 replicates per group and then reared either at a normal temperature (22 ± 1 °C) or at a high ambient temperature (34 ± 1 °C for 8 h and 22 ± 1 °C for the remaining time) for 20 d. Broilers in the 5 groups were fed a basal diet at a normal temperature (NT group) and a basal diet with 0, 50, 100, and 200 mg/kg curcumin at a high ambient temperature (HT, CUR50, CUR100, and CUR200 groups), respectively. The serum and liver samples were analyzed for the parameters related to hepatic damage, mitochondrial function, and redox status. The results showed that the G:F was increased in the CUR50 and CUR100 groups, and the final BW was increased in CUR100 group in comparison with the HT group (P < 0.05). When compared with those in the HT group, both serum aspartate and alanine aminotransferase activities were decreased in the curcumin-supplemented groups (P < 0.05). Curcumin decreased the reactive oxygen species (ROS) production but increased the mitochondrial membrane potential in the hepatocytes of the broilers after heat stress (P < 0.05). The broilers in curcumin-supplemented groups had lower malondialdehyde and protein carbonyl concentrations as well as greater thiol concentrations (P < 0.05). The mitochondrial manganese superoxide dismutase (MnSOD) activity in the liver was increased (P < 0.05) in the CUR100 group compared with the HT group. Compared with the heat-stressed broilers, the broilers that were fed curcumin had greater (P < 0.05) mtDNA copy number and ATP concentrations than those in the HT group. Curcumin supplementation attenuated the depression of the thioredoxin 2 and peroxiredoxin-3 gene expressions (P < 0.05). The MnSOD gene expression was increased in the CUR100 and CUR200 groups, and the thioredoxin reductase 2 gene expression was increased in the CUR50 group in comparison with the HT group (P < 0.05). In conclusion, curcumin mitigated the mitochondrial dysfunction in heat-stressed broilers, as evidenced by the suppression of the ROS burst, the maintenance of the thiol pool and mtDNA content, and the enhanced mitochondrial antioxidant gene expression.

Inhibition of autophagy with bafilomycin and chloroquine decreases mitochondrial quality and bioenergetic function in primary neurons.

Autophagy is an important cell recycling program responsible for the clearance of damaged or long-lived proteins and organelles. Pharmacological modulators of this pathway have been extensively utilized in a wide range of basic research and pre-clinical studies. Bafilomycin A1 and chloroquine are commonly used compounds that inhibit autophagy by targeting the lysosomes but through distinct mechanisms. Since it is now clear that mitochondrial quality control, particularly in neurons, is dependent on autophagy, it is important to determine whether these compounds modify cellular bioenergetics. To address this, we cultured primary rat cortical neurons from E18 embryos and used the Seahorse XF96 analyzer and a targeted metabolomics approach to measure the effects of bafilomycin A1 and chloroquine on bioenergetics and metabolism. We found that both bafilomycin and chloroquine could significantly increase the autophagosome marker LC3-II and inhibit key parameters of mitochondrial function, and increase mtDNA damage. Furthermore, we observed significant alterations in TCA cycle intermediates, particularly those downstream of citrate synthase and those linked to glutaminolysis. Taken together, these data demonstrate a significant impact of bafilomycin and chloroquine on cellular bioenergetics and metabolism consistent with decreased mitochondrial quality associated with inhibition of autophagy.

Bu Shen Tiao Chong recipe restores diminished ovary reserve through the BDNF pathway.

PURPOSE: The purpose of this study was to explore the molecular pathway of BSTCR (Bu Shen Tiao Chong recipe) in retrieving diminished ovary reserve (DOR). METHODS: The DOR model was established through injecting cyclophosphamide and the effect of BSTCR was examined under this background. RESULTS: BSTCR was shown to restore depleted brain-derived neurotrophic factor (BDNF), CDC2, cyclin B, GSH1, and P38 levels as well as impaired oocyte maturation and the higher apoptosis induced in DOR. BSTCR also enhances the response of oocytes to in vitro fertilization, with higher implantation rate, birth rate, and placenta weight. CONCLUSION: BSTCR might exert its beneficial role in oocyte maturation and restore DOR through regulating the BDNF pathway. And this pathway itself is probably through the consequence on several serum hormones such as FSH, E2, Inhibin B, etc.

Effects of ginseng on peripheral blood mitochondrial DNA copy number and hormones in men with metabolic syndrome: A randomized clinical and pilot study.

BACKGROUND: It has been observed that mitochondrial dysfunction is associated with an increased risk of metabolic syndrome. There is growing evidence that hyperactivity of the hypothalamus-pituitary-adrenal (HPA) axis and hormone (testosterone and growth hormone) deficiency may lead to metabolic syndrome. Recent studies have reported that ginseng treatment improves mitochondrial and HPA-axis function and increases anabolic hormone secretion. OBJECTIVES: The objective of this study was to investigate the effect of red ginseng (RG) on metabolic syndrome, hormones, and mitochondrial function using leukocyte mitochondrial DNA copy number in men with metabolic syndrome. METHODS: We performed a randomized, double-blind, placebo-controlled study in 62 subjects who were not taking drugs that could affect their metabolic function. A total of 62 men with metabolic syndrome were randomly assigned to either an RG group (3.0g/day) or a placebo group for 4 weeks. We analyzed changes in metabolic syndrome components, leukocyte mitochondrial DNA copy number, hormones (total testosterone, IGF-1, cortisol, and DHEAS) and inflammatory markers (C-reactive protein, ferritin) from baseline to 4 weeks. RESULTS: Significant improvement in mitochondrial function (95% CI -44.9 to -1.3) and an increase in total testosterone (95% CI -70.1 to -1.0) and IGF-1(P=0.01) levels were observed in the RG group when compared with the placebo group. Diastolic blood pressure (95% CI 2.0-9.4) and serum cortisol (95% CI 1.1-5.5) significantly decreased in the RG group. CONCLUSIONS: We found evidence that RG had a favorable effect on mitochondrial function and hormones in men with metabolic syndrome.

Vitamin A exerts its antiinflammatory activities in colitis through preservation of mitochondrial activity.

OBJECTIVES: The aim of this study was to assess the protective effects of vitamin A in a rat model of colitis to elucidate a possible mechanism of action. METHODS: Male rats were fed for 21 d with either a normal diet or high vitamin A diet (5000 IU/d). On day 22, colitis was induced with 2,4,6-trinitrobenzenesulfonic acid (TNBS). Rats were sacrificed after 24 h and colonic tissue was removed for evaluation. RESULTS: Morphologically, in the supplemented group preservation of tissue architecture, no vasculitis or necroses were detected. Biochemically, decreased myeloperoxidase activity and protection of the mitochondria as evaluated by preserving tissue oxygen consumption, mitochondrial DNA, and expression of cytochrome c, was observed. Vitamin A supplementation also increased the levels of nuclear respiratory factor (NFR)-1 and mitochondrial transcription factor-A (TFAM) in normal colon tissue and in colon tissue under inflammatory conditions. CONCLUSION: The results indicate that tissue damage in colitis is accompanied by the arrest of mitochondrial respiration, loss of mitochondrial DNA, and the expression of mitochondrial proteins. Vitamin A effectively protects colon mitochondria by upregulation of mitochondrial transcription factors, NFR-1 and TFAM, and prevents inflammatory and necrotic changes in colitis. Vitamin A is therefore a potential therapeutic agent in inflammatory bowel disease.

Quercetin supplementation does not enhance cerebellar mitochondrial biogenesis and oxidative status in exercised rats.

The present study tested the hypothesis that quercetin may inhibit the mitochondrial and antioxidant adaptations induced by exercise in cerebellar tissue. Thirty-five 6-week-old Wistar rats were randomly allocated into the following groups: quercetin, exercised (Q-Ex; n = 9); quercetin, sedentary (Q-Sed; n = 9); no quercetin, exercised (NQ-Ex; n = 9); and no quercetin, sedentary (NQ-Sed; n = 8). After 6 weeks of quercetin supplementation and/or exercise training, cerebellums were collected. Protein carbonyl content (PCC), sirtuin 1, peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α), messenger RNA levels, citrate synthase (CS), and mitochondrial DNA were measured. When Q-Sed was compared with NQ-Sed, PCC (P < .005) showed decreased levels, whereas PGC-1α, sirtuin 1 (both, P < .01), mitochondrial DNA (P < .001), and CS (P < .01) increased. However, when Q-Ex was compared with Q-Sed, PCC showed increased levels (P < .001), whereas CS decreased (P < .01). Furthermore, the NQ-Ex group experienced an increase in PGC-1α messenger RNA levels in comparison with NQ-Sed (P > .01). This effect, however, did not appear in Q-Ex (P < .05). Therefore, we must hypothesize that either the dose (25 mg/kg) or the length of the quercetin supplementation period that was used in the present study (or perhaps both) may impair exercise-induced adaptations in cerebellar tissue.

Protective effect of KI in mtDNA in porcine thyroid: comparison with KIO3 and nDNA.

PURPOSE: Iodine, bivalent iron (Fe²âº), and hydrogen peroxide (H2O2), all significantly affecting the red-ox balance, are required for thyroid hormone synthesis. Intracellular iodine excess (≥10⁻³ M) transiently blocks thyroid hormonogenesis (an adaptive mechanism called Wolff-Chaikoff effect). The aim of the study was to evaluate the effects of iodine, used as potassium iodide (KI) or potassium iodate (KIO3), in concentrations corresponding to those typical for Wolff-Chaikoff effect, on the level of oxidative damage to nuclear DNA (nDNA) and mitochondrial DNA (mtDNA) isolated from porcine thyroid under basal conditions and in the presence of Fenton reaction (Fe²âº+H2O2 → Fe³âº+(·)OH + OH⁻) substrates. METHODS: Thyroid nDNA and mtDNA were incubated in the presence of either KI or KIO3 (2.5-50 mM), without/with FeSO4 (30 µM) + H2O2 (0.5 mM). Index of DNA damage, i.e., 8-oxo-7,8-dihydro-2'-deoxyguanosine, was measured by HPLC. RESULTS: Neither KI nor KIO3 increased the basal level of 8-oxodG in both nDNA and mtDNA. KI-in all used concentrations-completely prevented the damaging effect of Fenton reaction substrates in mtDNA, and it partially prevented this damage in nDNA. KIO3 partially prevented Fe²âº+H2O2-induced oxidative damage in both DNA only in its highest used concentrations (≥25 mM). CONCLUSIONS: Without additional prooxidative abuse, both iodine compounds, i.e., KI and KIO3, seem to be safe in terms of their potential oxidative damage to DNA in the thyroid. The superiority of KI over KIO3 relies on its stronger protective effects against oxidative damage to mtDNA, which constitutes an argument for its preferential utility in iodine prophylaxis.

Dietary lipid unsaturation influences survival and oxidative modifications of an amyotrophic lateral sclerosis model in a gender-specific manner.

The implication of lipid peroxidation in neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS) derive from high abundance of peroxidation-prone polyunsaturated fatty acids in central nervous system and its relatively low antioxidant content. In the present work, we evaluated the effect of dietary changes aimed to modify fatty acid tissular composition in survival, disease onset, protein, and DNA oxidative modifications in the hSODG93A transgenic mice, a model of this motor neuron disease. Both survival and clinical evolution is dependent on dietary fatty acid unsaturation and gender, with high unsaturated diet, leading to loss of the disease-sparing effect of feminine gender. This was associated with significant increases in protein carbonyl and glycoxidative modifications as well as non-nuclear 8-oxo-dG, a marker of mitochondrial DNA oxidation. Comparison of these data with γH2AX immunostaining, a marker of DNA damage response, suggests that the highly unsaturated diet-blunted mitochondrial-nuclear free radical dependent crosstalk, since increased 8-oxo-dG was not correlated with increased DNA damage response. Paradoxically, the highly unsaturated diet led to lower peroxidizability but higher anti-inflammatory indexes. To sum up, our results demonstrate that high polyunsaturated fatty acid content in diets may accelerate the disease in this model. Further, these results reinforce the need for adequately defining gender as a relevant factor in ALS models, as well as to use structurally characterized markers for oxidative damage assessment in neurodegeneration.

Grape seed proanthocyanidin extracts ameliorate podocyte injury by activating peroxisome proliferator-activated receptor-γ coactivator 1α in low-dose streptozotocin-and high-carbohydrate/high-fat diet-induced diabetic rats.

Podocytes are part of the glomerular filtration membrane in kidney and serve to prevent the filtration of protein from the blood. Several evidences suggest that mitochondrial dysfunction plays a critical role in the pathogenesis of diabetic nephropathy and it is an early event in podocyte injury. Mitochondrial dysfunction promotes oxidative stress that can favor the development of podocyte injury. Peroxisome proliferator-activated receptor-γ coactivator 1α (PGC-1α) was considered to be a major regulator of metabolic homeostasis and mitochondrial function. Some studies indicated that polyphenols may improve mitochondrial dysfunction, maintain the podocyte integrity and have therapeutic effects on glomerular diseases by promoting PGC-1α expression. Our study investigated whether grape seed proanthocyanidin extracts (GSPE), a strong antioxidant, ameliorate podocyte injury by activating PGC-1α in low-dose streptozotocin-and high-carbohydrate/high-fat diet-induced diabetic rats. After 16 weeks of GSPE treatment, GSPE slightly increased the body weight and decreased plasma glucose, food intake, water intake and urine volume in diabetic rats. Further, GSPE significantly decreased 24 h albumin levels and increased the expression of nephrin and podocalyxin. The antioxidant levels were improved and the cellular damage of kidney in diabetic rats was also relieved effectively after the treatment. Moreover, GSPE increased the mRNA expression of mitochondrial biogenesis factors and mitochondrial DNA content. Finally, GSPE activated the expression of PGC-1α, silent mating type information regulation 2 homolog 1 (SIRT1) and AMP-activated protein kinase (AMPK). These results suggest that GSPE ameliorate podocyte injury in diabetic nephropathy by the activation of AMPK-SIRT1-PGC-1α signalling, which appears to inhibit oxidative stress and mitochondrial dysfunction in the kidney.