Spilanthes acmella Murr. ameliorates chronic stress through improving mitochondrial function in chronic restraint stress rats.

Chronic stress is a risk factor for the development of psychiatric illnesses through impairment of the ability to appropriately regulate physiological and behavioral responses, but the molecular events that lead to damage of hippocampal neurons remain unclear. The medicinal herb Spilanthes acmella Murr. has been used as a traditional medicine for various diseases and its extracts exhibit antioxidant activity. The present study explored the molecular signals of mitochondrial dynamics and investigated the beneficial effects of S. acmella Murr. An ethyl acetate extract of this plant was used to assess mitochondrial dynamics in response to chronic restraint stress (CRS) in male Sprague-Dawley rats. The results demonstrated that the S. acmella Murr. extract reduced the expression of mitochondrial fission protein but induced HSP60, MnSOD and ATPsynthase in the hippocampus of the CRS rats. In addition, S. acmella Murr. extract reversed depressive symptoms in the forced swim test. Our findings suggested that S. acmella Murr. extract provides a potential treatment of chronic stress, and that the mechanism is associated with the alleviation of neuronal injury and maintenance of mitochondrial function.

Mitochondrial fission protein 1 up-regulation ameliorates senescence-related endothelial dysfunction of human endothelial progenitor cells.

BACKGROUND: We investigated the contribution of mitochondrial dysfunction to the senescence of human endothelial progenitor cells (EPCs) expanded in vitro and the underlying molecular mechanism. METHODS AND RESULTS: Serial passage increased cell doubling time and those cells reaching the doubling time for more than 100% were defined as senescent EPCs, of which the activity of therapeutic angiogenesis was attenuated in mouse ischemic hindlimbs. The senescent cells, in medium free of glucose and bicarbonate, showed impaired activity in migration and tube formation. Flow cytometry indicated increased content of reactive oxygen species, mitochondria, and calcium, while bioenergetic analysis showed increased oxygen consumption and reduced ATP content. Examination of mitochondrial network showed that senescence increased the length of the network and ultrastructure analysis exhibited elongated mitochondria. Immunoblotting of the senescent EPCs demonstrated decreased expression level of fission protein1 (Fis1). In rat EPCs, the Fis1 level was decreased in the animals aged 24 months or older, compared to those of 3 months. Silencing of Fis1 in the young EPCs using Fis1-specific siRNA leads to appearance of phenotype resembling those of senescent cells, including elevated oxidative stress, disturbed mitochondrial network, reduced mitochondria membrane potential, decreasing ATP content, lower proliferation activity, and loss of therapeutic potential in ischemic hindlimbs. Fis1 over-expression in senescent EPCs reduced the oxidative stress, increased the proliferation, and restored the cobble stone-like morphology, senescence, bioenergetics, angiogenic potential, and therapeutic activity. CONCLUSION: In human EPCs, down-regulation of Fis1 is involved in mitochondrial dysfunction and contributes to the impaired activity of EPCs during the senescence process. Enhanced expression of Fis1 in senescent EPCs restores the youthful phenotype.

Withaferin A-mediated apoptosis in breast cancer cells is associated with alterations in mitochondrial dynamics.

Withaferin A (WA), a steroidal lactone derived from a medicinal plant (Withania somnifera), inhibits cancer development in transgenic and chemically-induced rodent models of breast cancer but the underlying mechanism is not fully grasped. We have shown previously that WA treatment causes apoptotic cell death in human breast cancer cells that is preceded by inhibition of complex III of the mitochondrial electron transport chain. This study extends these observations to now demonstrate alterations in mitochondrial dynamics in WA-induced apoptosis. Assembly of complex III was decreased in MCF-7 and SUM159 cells but not in MDA-MB-231 as determined by native blue gel electrophoresis. Because WA is a Michael acceptor (electrophile), we explored the possibility of whether it covalently modifies cysteine residue(s) in ubiquinol-cytochrome c reductase, Rieske iron-sulfur polypeptide 1 (UQCRFS1). Covalent modification of cysteine in UQCRFS1 was not observed after WA treatment. Instead, WA treatment inhibited chemically-induced mitochondrial fusion and decreased the mitochondrial volume, and this effect was accompanied by a decrease in the expression of proteins involved in fusion process, including mitofusin1, mitofusin2, and full-length optic atrophy protein 1 (OPA1). A loss of volume in fragmented mitochondria also occurred in WA-exposed cells when compared to vehicle-treated control. WA treatment also caused a decrease in protein level of mitochondrial fission-regulating protein dynamin-related protein 1 (DRP1). Functional studies revealed that DRP1 deficiency and OPA1 knockdown attenuated apoptotic potential of WA. Taken together, these results indicate that WA not only alters Complex III assembly but also inhibits mitochondrial dynamics in breast cancer cells.

Effect of Qiangji Jianli decoction on mitochondrial respiratory chain activity and expression of mitochondrial fusion and fission proteins in myasthenia gravis rats.

Myasthenia gravis (MG) is an autoimmune neuromuscular disease characterized by the production of antibodies against acetylcholine receptors (AChRs). Qiangji Jianli (QJJL) decoction is an effective traditional Chinese medicine (TCM) that is used to treat MG. Our study aimed to investigate the effect of QJJL decoction on MG and to clarify the mechanism by which QJJL regulates mitochondrial energy metabolism and mitochondrial fusion and fission (MFF). SPF female Lewis rats were administered Rat 97-116 peptides to induce experimental autoimmune myasthenia gravis (EAMG). The treatment groups received QJJL decoction (7.8 g/kg, 15.6 g/kg and 23.4 g/kg). Mitochondria were extracted from gastrocnemius tissue samples to detect respiratory chain complex enzymatic activity. Quantitative PCR and western blot analysis were performed to detect Mfn1/2, Opa1, Drp1 and Fis1 mRNA and protein expression, respectively, in the mitochondria. Transmission electron microscopy examination was performed to show the improvement of mitochondria and myofibrils after QJJL treatment. The results indicated that QJJL decoction may attenuate MG by promoting the enzymatic activity of respiratory chain complexes to improve energy metabolism. Moreover, QJJL decoction increased Mfn1/2, Opa1, Drp1 and Fis1 mRNA and protein expression to exert its curative effect on MFF. Thus, QJJL decoction may be a promising therapy for MG.

Curcumin prevents mitochondrial dynamics disturbances in early 5/6 nephrectomy: Relation to oxidative stress and mitochondrial bioenergetics.

Five-sixths nephrectomy (5/6NX) is a widely used model to study the mechanisms leading to renal damage in chronic kidney disease (CKD). However, early alterations on renal function, mitochondrial dynamics, and oxidative stress have not been explored yet. Curcumin is an antioxidant that has shown nephroprotection in 5/6NX-induced renal damage. The aim of this study was to explore the effect of curcumin on early mitochondrial alterations induced by 5/6NX in rats. In isolated mitochondria, 5/6NX-induced hydrogen peroxide production was associated with decreased activity of complexes I and V, decreased activity of antioxidant enzymes, alterations in oxygen consumption and increased MDA-protein adducts. In addition, it was found that 5/6NX shifted mitochondrial dynamics to fusion, which was evidenced by increased optic atrophy 1 and mitofusin 1 (Mfn1) and decreased fission 1 and dynamin-related protein 1 expressions. These data were confirmed by morphological analysis and immunoelectron microscopy of Mfn-1. All the above-described mechanisms were prevented by curcumin. Also, it was found that curcumin prevented renal dysfunction by improving renal blood flow and the total antioxidant capacity induced by 5/6NX. Moreover, in glomeruli and proximal tubules 5/6NX-induced superoxide anion production by uncoupled nitric oxide synthase (NOS) and nicotinamide adenine dinucleotide phosphate oxidase (NOX) dependent way, this latter was associated with increased phosphorylation of serine 304 of p47phox subunit of NOX. In conclusion, this study shows that curcumin pretreatment decreases early 5/6NX-induced altered mitochondrial dynamics, bioenergetics, and oxidative stress, which may be associated with the preservation of renal function. © 2016 BioFactors, 43(2):293-310, 2017.

Training Enhances Immune Cells Mitochondrial Biosynthesis, Fission, Fusion, and Their Antioxidant Capabilities Synergistically with Dietary Docosahexaenoic Supplementation.

Exercise training induces adaptations in mitochondrial metabolism, dynamics, and oxidative protection. Omega-3 fatty acids change membrane lipid composition and modulate mitochondrial function. The aim was to investigate the effect of 8-week training and docosahexaenoic acid (DHA) supplementation (1.14 g/day) on the mitochondria dynamics and antioxidant status in peripheral blood mononuclear cells (PBMCs) from sportsmen. Subjects were assigned to an intervention (N = 9) or placebo groups (N = 7) in a randomized double-blind trial. Nutritional intervention significantly increased the DHA content in erythrocyte membranes from the experimental group. No significant differences were reported in terms of circulating PBMCs, Mn-superoxide dismutase protein levels, and their capability to produce reactive oxygen species. The proteins related to mitochondrial dynamics were, in general, increased after an 8-week training and this increase was enhanced by DHA supplementation. The content in mitofusins Mtf-1 and Mtf-2, optic atrophy protein-1 (Opa-1), and mitochondrial transcription factor A (Tfam) were significantly higher in the DHA-supplemented group after intervention. Cytochrome c oxidase (COX-IV) activity and uncoupling proteins UCP-2 and UCP-3 protein levels were increased after training, with higher UCP-3 levels in the supplemented group. In conclusion, training induced mitochondrial adaptations which may contribute to improved mitochondrial function. This mitochondrial response was modulated by DHA supplementation.

Maternal stress predicts altered biogenesis and the profile of mitochondrial proteins in the frontal cortex and hippocampus of adult offspring rats.

Currently, much attention is focused on the influence of mitochondrial disturbances at the onset of depression. The goal of this study was to investigate the impact of prenatal stress (an animal model of depression) on the mitochondrial biogenesis proteins and mitoproteome profile in the frontal cortex and hippocampus of adult 3-month-old male rats following a prenatal stress procedure. Our results show that rats that were exposed to prenatal stress stimuli displayed depression-like behaviors based on the sucrose preference and elevated plus maze tests. It has been found that the level of the PGC-1α protein was reduced in the frontal cortex and hippocampus of the adult offspring after the prenatal stress procedure. Moreover, in the frontal cortex, the level of the pro-apoptotic protein Bax was up-regulated. Two-dimensional electrophoresis coupled with mass spectrometry showed the statistically significant down-regulation of the mitochondrial ribosomal protein L12 (Mrpl12) and mitochondrial NADH dehydrogenase [ubiquinone] flavoprotein 2 (NDUFV2) as well as the up-regulation of the Tubulin Polymerization Promoting Proteins (Tppp/p25) in the frontal cortex. In contrast, in the hippocampus, the mitochondrial pyruvate dehydrogenase E1 component subunit beta, the voltage-dependent anion-selective channel protein 2 (VDAC2), and the GTP-binding nuclear protein RAN (RAN) were down-regulated and the expression of phosphatidylethanolamine-binding protein 1 (PEBP-1) was enhanced. These findings provide new evidence that stress during pregnancy may lead not only to behavioral deficits, but also to disturbances in the brain mitoproteome profile in adult rat offspring.

High levels of X-linked Inhibitor-of-Apoptosis Protein (XIAP) are indicative of radio chemotherapy resistance in rectal cancer.

BACKGROUND: The mainstay of treatment in rectal cancer is neoadjuvant radio chemotherapy prior to surgery, in an attempt to downstage the tumour, allowing for more complete removal during surgery. In 40 % of cases however, this neoadjuvant radio chemotherapy fails to achieve tumour regression, partly due insufficient apoptosis signaling. X-linked Inhibitor of Apoptosis Protein (XIAP) is an anti-apoptotic protein that has been reported to contribute to disease progression and chemotherapy resistance. METHODS: We obtained rectal biopsy normal and matched tumour tissue from 29 rectal cancer patients with varying degrees of tumour regression, and using Western blot, examined anti-apoptotic XIAP and pro-apoptotic Smac protein levels in these tissues, with the aim to examine whether disturbed XIAP/Smac levels may be an indicator of neoadjuvant radio chemotherapy resistance. Expression of inhibitor of apoptosis proteins cIAP-1 and cIAP-2 was also examined. RESULTS: We found that levels of XIAP increased in accordance with the degree of radio chemotherapy resistance of the tissue. Levels of this protein were also significantly higher in tumour tissue, compared to matched normal tissue in highly resistant tissue. In contrast, Smac protein levels did not increase with radio chemotherapy resistance, and the protein was similarly expressed in normal and tumour tissue, indicating a shift in the balance of these proteins. Post treatment surgical resection tissue was available for 8 patients. When we compared matched tissue pre- and post- radio chemotherapy we found that XIAP levels increased significantly during treatment in both normal and tumour tissue, while Smac levels did not change. cIAP-1 and cIAP-2 levels were not differentially expressed in varying degrees of radio chemotherapy resistance, and neoadjuvant therapy did not alter expression of these proteins. CONCLUSION: These data indicate that disturbance of the XIAP/Smac balance may be a driver of radio chemotherapy resistance, and hence high levels of XIAP may be a useful indicator of neoadjuvant radio chemotherapy resistance in rectal cancer. Moreover, as XIAP levels increase with radio chemotherapy it is possible that a subset of more resistant tumour cells survive this treatment and may be resistant to further adjuvant treatment. Patients with resistant tumours highly expressing XIAP may benefit from alternative treatment strategies, such as Smac mimetics post neoadjuvant radio chemotherapy.

Protein ingestion increases myofibrillar protein synthesis after concurrent exercise.

PURPOSE: We determined the effect of protein supplementation on anabolic signaling and rates of myofibrillar and mitochondrial protein synthesis after a single bout of concurrent training. METHODS: Using a randomized crossover design, eight healthy males were assigned to experimental trials consisting of resistance exercise (8 × 5 leg extension, 80% 1RM) followed by cycling (30 min at approximately 70% V˙O2peak) with either postexercise protein (PRO, 25-g whey protein) or placebo (PLA) ingestion. Muscle biopsies were obtained at rest and at 1 and 4 h after exercise. RESULTS: Akt and mTOR phosphorylation increased 1 h after exercise with PRO (175%-400%, P < 0.01) and was different from PLA (150%-300%, P < 0.001). Muscle RING finger 1 and atrogin-1 messenger RNA (mRNA) were elevated after exercise but were higher with PLA compared with those in PRO at 1 h (50%-315%, P < 0.05), whereas peroxisome proliferator-activated receptor gamma coactivator 1-alpha mRNA increased 4 h after exercise (620%-730%, P < 0.001), with no difference between treatments. Postexercise rates of myofibrillar protein synthesis increased above rest in both trials (75%-145%, P < 0.05) but were higher with PRO (67%, P < 0.05), whereas mitochondrial protein synthesis did not change from baseline. CONCLUSIONS: Our results show that a concurrent training session promotes anabolic adaptive responses and increases metabolic/oxidative mRNA expression in the skeletal muscle. PRO ingestion after combined resistance and endurance exercise enhances myofibrillar protein synthesis and attenuates markers of muscle catabolism and thus is likely an important nutritional strategy to enhance adaptation responses with concurrent training.

Dietary Astragalus polysaccharide alleviated immunological stress in broilers exposed to lipopolysaccharide.

This study was conducted to investigate whether dietary Astragalus polysaccharide (APS) could alleviate immunological stress response of chickens after challenge with lipopolysaccharide (LPS). A total of 360 one-day-old commercial Arbor Acres broilers were randomly assigned in a 2 × 2 factorial design. The main factors were immunological stress (LPS or saline) and dietary APS (0 or 3g APS/kg feed). At 12, 14, 33 and 35 days of age, chickens were injected intramuscularly with either 500 µg/kg body weight of LPS or sterile saline. The results showed that the decreased daily feed intake and daily weight gain caused by immunological stress were dramatically attenuated by APS supplementation. The LPS challenge led to an increased mRNA abundance of TLR4, NF-κB, IL-1ß, IL-6, avian uncoupling protein, α1-acid glycoprotein, hemopexin and y(+)LAT2. However, these negative effects of the LPS administration were ameliorated by APS supplementation. Moreover, dietary APS inhibited the LPS-induced depression of amino acid digestibilities. In conclusion, APS is able to alleviate LPS-induced immunological stress response in chickens. The beneficial effect may be attributed to suppressing the expression of pro-inflammatory cytokines through reducing the TLR4 and NF-κB genes transcription, and therewith improving energy and protein metabolism.

Nonclinical and pharmacokinetic assessments to evaluate the potential of tedizolid and linezolid to affect mitochondrial function.

Prolonged treatment with the oxazolidinone linezolid is associated with myelosuppression, lactic acidosis, and neuropathies, toxicities likely caused by impairment of mitochondrial protein synthesis (MPS). To evaluate the potential of the novel oxazolidinone tedizolid to cause similar side effects, nonclinical and pharmacokinetic assessments were conducted. In isolated rat heart mitochondria, tedizolid inhibited MPS more potently than did linezolid (average [± standard error of the mean] 50% inhibitory concentration [IC50] for MPS of 0.31 ± 0.02 µM versus 6.4 ± 1.2 µM). However, a rigorous 9-month rat study comparing placebo and high-dose tedizolid (resulting in steady-state area under the plasma concentration-time curve values about 8-fold greater than those with the standard therapeutic dose in humans) showed no evidence of neuropathy. Additional studies explored why prolonged, high-dose tedizolid did not cause these mitochondriopathic side effects despite potent MPS inhibition by tedizolid. Murine macrophage (J774) cell fractionation studies found no evidence of a stable association of tedizolid with eukaryotic mitochondria. Monte Carlo simulations based on population pharmacokinetic models showed that over the course of a dosing interval using standard therapeutic doses, free plasma concentrations fell below the respective MPS IC50 in 84% of tedizolid-treated patients (for a median duration of 7.94 h) and 38% of linezolid-treated patients (for a median duration of 0 h). Therapeutic doses of tedizolid, but not linezolid, may therefore allow for mitochondrial recovery during antibacterial therapy. The overall results suggest that tedizolid has less potential to cause myelosuppression and neuropathy than that of linezolid during prolonged treatment courses. This, however, remains a hypothesis that must be confirmed in clinical studies.

Optimizing intramuscular adaptations to aerobic exercise: effects of carbohydrate restriction and protein supplementation on mitochondrial biogenesis.

Mitochondrial biogenesis is a critical metabolic adaptation to aerobic exercise training that results in enhanced mitochondrial size, content, number, and activity. Recent evidence has shown that dietary manipulation can further enhance mitochondrial adaptations to aerobic exercise training, which may delay skeletal muscle fatigue and enhance exercise performance. Specifically, studies have demonstrated that combining carbohydrate restriction (endogenous and exogenous) with a single bout of aerobic exercise potentiates the beneficial effects of exercise on markers of mitochondrial biogenesis. Additionally, studies have demonstrated that high-quality protein supplementation enhances anabolic skeletal muscle intracellular signaling and mitochondrial protein synthesis following a single bout of aerobic exercise. Mitochondrial biogenesis is stimulated by complex intracellular signaling pathways that appear to be primarily regulated by 5'AMP-activated protein kinase and p38 mitogen-activated protein kinase mediated through proliferator-activated γ receptor co-activator 1 α activation, resulting in increased mitochondrial DNA expression and enhanced skeletal muscle oxidative capacity. However, the mechanisms by which concomitant carbohydrate restriction and dietary protein supplementation modulates mitochondrial adaptations to aerobic exercise training remains unclear. This review summarizes intracellular regulation of mitochondrial biogenesis and the effects of carbohydrate restriction and protein supplementation on mitochondrial adaptations to aerobic exercise.

The isoflavone-rich fraction of the crude extract of the Puerariae flower increases oxygen consumption and BAT UCP1 expression in high-fat diet-fed mice.

Puerariae flower extract (PFE) is a crude extract of the Kudzu flower. Previous studies have shown that PFE supplementation exerts anti-obesity and anti-fatty liver effects in high-fat diet-fed mice. In this study, we aimed to identify the PFE components responsible for these effects and to determine their influence on energy expenditure and uncoupling protein 1 (UCP1) expression. Experiments were conducted on C57BL/6J male mice classified into 3 groups: (1) high-fat diet-fed (HFD), (2) high-fat diet-fed given PFE (HFD + PFE), and (3) high-fat diet-fed given the PFE isoflavone-rich fraction (HFD + ISOF). All groups were fed for 42 days. The HFD + PFE and HFD + ISOF groups showed significant resistance to increases in body weight, hepatic triglyceride level, and visceral fat compared to the HFD group. These groups also exhibited significant increases in oxygen consumption and UCP1-positive brown adipose tissue (BAT) area. Our results demonstrate that the active ingredients in PFE are present in the ISOF and that these compounds may increase energy expenditure by upregulation of BAT UCP1 expression. These findings provide valuable information regarding the anti-obesity effects of isoflavones.

DJ-1 protein protects dopaminergic neurons against 6-OHDA/MG-132-induced neurotoxicity in rats.

Parkinson disease (PD) is the second most common neurodegenerative disease, and it cannot be completely cured by current medications. In this study, DJ-1 protein was administrated into medial forebrain bundle of PD model rats those had been microinjected with 6-hydroxydopamine (6-OHDA) or MG-132. We found that DJ-1 protein could reduce apomorphine-induced rotations, inhibit reduction of dopamine contents and tyrosine hydroxylase levels in the striatum, and decrease dopaminergic neuron death in the substantia nigra. In 6-OHDA lesioned rats, uncoupling protein-4, uncoupling protein-5 and superoxide dismutase-2 (SOD2) mRNA and SOD2 protein were increased when DJ-1 protein was co-injected. Simultaneously, administration of DJ-1 protein reduced α-synuclein and hypoxia-inducible factor 1α mRNA and α-synuclein protein in MG-132 lesioned rats. Therefore, DJ-1 protein protected dopaminergic neurons in two PD model rats by increasing antioxidant capacity and inhibiting α-synuclein expression.

Mitochondrial biogenesis and increased uncoupling protein 1 in brown adipose tissue of mice fed a ketone ester diet.

We measured the effects of a diet in which D-ß-hydroxybutyrate-(R)-1,3 butanediol monoester [ketone ester (KE)] replaced equicaloric amounts of carbohydrate on 8-wk-old male C57BL/6J mice. Diets contained equal amounts of fat, protein, and micronutrients. The KE group was fed ad libitum, whereas the control (Ctrl) mice were pair-fed to the KE group. Blood d-ß-hydroxybutyrate levels in the KE group were 3-5 times those reported with high-fat ketogenic diets. Voluntary food intake was reduced dose dependently with the KE diet. Feeding the KE diet for up to 1 mo increased the number of mitochondria and doubled the electron transport chain proteins, uncoupling protein 1, and mitochondrial biogenesis-regulating proteins in the interscapular brown adipose tissue (IBAT). [(18)F]-Fluorodeoxyglucose uptake in IBAT of the KE group was twice that in IBAT of the Ctrl group. Plasma leptin levels of the KE group were more than 2-fold those of the Ctrl group and were associated with increased sympathetic nervous system activity to IBAT. The KE group exhibited 14% greater resting energy expenditure, but the total energy expenditure measured over a 24-h period or body weights was not different. The quantitative insulin-sensitivity check index was 73% higher in the KE group. These results identify KE as a potential antiobesity supplement.

Mitochondrial dysfunction during in vitro hepatocyte steatosis is reversed by omega-3 fatty acid-induced up-regulation of mitofusin 2.

We examined the effects and mechanisms of omega-3 polyunsaturated fatty acid (PUFA) administration on mitochondrial morphology and function in an in vitro steatotic hepatocyte model created using HepG2 cells. Reverse transcriptase polymerase chain reaction and Western blot analyses were performed to determine the expression levels of mitofusin 2 (Mfn2), and immunofluorescent MitoTracker Mitochondrion-Selective Probes were used to detect changes in mitochondrial morphology. Adenosine triphosphate (ATP) synthesis and reactive oxygen species (ROS) production were measured to assess mitochondrial function. Mitofusin 2 expression was significantly suppressed (P < .05), ATP levels were decreased (P < .05), ROS production was increased (P < .05), and the normal tubular network of mitochondria was fragmented into short rods or spheres. Model cells were incubated with eicosapentaenoic acid or docosahexaenoic acid at a final concentration of 50 µmol/L for 1 hour. Both eicosapentaenoic acid and docosahexaenoic acid increased the expression of Mfn2 (P < .01) and caused an increase in the length of mitochondrial tubules. The omega-3 PUFAs also increased the levels of ATP (P < .05) and decreased the ROS production (P < .05). However, these changes were not seen in Mfn2-depleted steatotic HepG2 cells, created by RNA interference before incubation with the omega-3 PUFAs. This study demonstrated that, in steatotic hepatocytes, omega-3 PUFAs may change mitochondrial morphology and have beneficial effects on recovery of mitochondrial function by increasing the expression of Mfn2.

Acute starvation in C57BL/6J mice increases myocardial UCP2 and UCP3 protein expression levels and decreases mitochondrial bio-energetic function.

Associations between uncoupling protein (UCP) expression and functional changes in myocardial mitochondrial bio-energetics have not been well studied during periods of starvation stress. Our aim was to study the effects of acute starvation, for 24 or 48 h, on combined cardiac mitochondrial function and UCP expression in mice. Isolated heart mitochondria from female mice starved for 48 h compared to that from mice fed revealed a significantly (p < 0.05) decreased adenosine diphosphate-to-oxygen ratio, a significantly increased proton leak and an increased GTP inhibition on palmitic acid-induced state 4 oxygen consumption (p < 0.05). These bio-energetic functional changes were associated with increases in mitochondrial UCP2 and UCP3 protein expression. In conclusion, our findings suggest that increased UCP2 and UCP3 levels may contribute to decreased myocardial mitochondrial bio-energetic function due to starvation.

Normal and Friedreich ataxia cells express different isoforms of frataxin with complementary roles in iron-sulfur cluster assembly.

Friedreich ataxia (FRDA) is an autosomal recessive degenerative disease caused by insufficient expression of frataxin (FXN), a mitochondrial iron-binding protein required for Fe-S cluster assembly. The development of treatments to increase FXN levels in FRDA requires elucidation of the steps involved in the biogenesis of functional FXN. The FXN mRNA is translated to a precursor polypeptide that is transported to the mitochondrial matrix and processed to at least two forms, FXN(42-210) and FXN(81-210). Previous reports suggested that FXN(42-210) is a transient processing intermediate, whereas FXN(81-210) represents the mature protein. However, we find that both FXN(42-210) and FXN(81-210) are present in control cell lines and tissues at steady-state, and that FXN(42-210) is consistently more depleted than FXN(81-210) in samples from FRDA patients. Moreover, FXN(42-210) and FXN(81-210) have strikingly different biochemical properties. A shorter N terminus correlates with monomeric configuration, labile iron binding, and dynamic contacts with components of the Fe-S cluster biosynthetic machinery, i.e. the sulfur donor complex NFS1·ISD11 and the scaffold ISCU. Conversely, a longer N terminus correlates with the ability to oligomerize, store iron, and form stable contacts with NFS1·ISD11 and ISCU. Monomeric FXN(81-210) donates Fe(2+) for Fe-S cluster assembly on ISCU, whereas oligomeric FXN(42-210) donates either Fe(2+) or Fe(3+). These functionally distinct FXN isoforms seem capable to ensure incremental rates of Fe-S cluster synthesis from different mitochondrial iron pools. We suggest that the levels of both isoforms are relevant to FRDA pathophysiology and that the FXN(81-210)/FXN(42-210) molar ratio should provide a useful parameter to optimize FXN augmentation and replacement therapies.

Herba Cistanche extract enhances mitochondrial glutathione status and respiration in rat hearts, with possible induction of uncoupling proteins.

Herba Cistanche, a Chinese herb derived from the whole plant of Cistanche deserticola Y.C. Ma (Orobanchaceae), has been shown to enhance mitochondrial ATP generation and to protect against myocardial ischemia/reperfusion (I/R) injury ex vivo in rats. To define the role of mitochondria in the cardioprotective action of Herba Cistanche, we investigated the effect of Herba Cistanche treatment on mitochondrial glutathione status and functional parameters in rat hearts. Treatment with a methanol extract of Herba Cistanche enhanced mitochondrial glutathione status, decreased mitochondrial Ca(2+) content, and increased mitochondrial membrane potential. In addition, an increase in State 4 respiration, indicative of uncoupled respiration, was observed in mitochondria isolated from Herba Cistanche-treated rat hearts. The enhancement of mitochondrial glutathione status and functional ability, as well as the putative induction of uncoupling proteins, may be related to cardioprotection afforded by Herba Cistanche treatment protecting against I/R injury.

A ketone ester diet increases brain malonyl-CoA and Uncoupling proteins 4 and 5 while decreasing food intake in the normal Wistar Rat.

Three groups of male Wistar rats were pair fed NIH-31 diets for 14 days to which were added 30% of calories as corn starch, palm oil, or R-3-hydroxybutyrate-R-1,3-butanediol monoester (3HB-BD ester). On the 14th day, animal brains were removed by freeze-blowing, and brain metabolites measured. Animals fed the ketone ester diet had elevated mean blood ketone bodies of 3.5 mm and lowered plasma glucose, insulin, and leptin. Despite the decreased plasma leptin, feeding the ketone ester diet ad lib decreased voluntary food intake 2-fold for 6 days while brain malonyl-CoA was increased by about 25% in ketone-fed group but not in the palm oil fed group. Unlike the acute effects of ketone body metabolism in the perfused working heart, there was no increased reduction in brain free mitochondrial [NAD(+)]/[NADH] ratio nor in the free energy of ATP hydrolysis, which was compatible with the observed 1.5-fold increase in brain uncoupling proteins 4 and 5. Feeding ketone ester or palm oil supplemented diets decreased brain L-glutamate by 15-20% and GABA by about 34% supporting the view that fatty acids as well as ketone bodies can be metabolized by the brain.