Mitochondrial Dysfunction In Mice Research Articles

Protective role of mesenchymal stem cells and mesenchymal stem cell-derived exosomes in cigarette smoke-induced mitochondrial dysfunction in mice

BackgroundCigarette smoke (CS)-induced lung inflammation and Chronic Obstructive Pulmonary disease (COPD) involves mitochondrial dysfunction. Mesenchymal stem cells (MSC) and MSC-derived exosomes (EXO) are reported to show therapeutic effects in many animal models of inflammation and injury. In the present study, we determined the role of MSC and EXO intervention in CS-induced lung inflammation with a focus on mitochondrial dysfunction. MethodsEXO were characterized using Western blot for exosomal markers, tunable resistive pulse sensing by qNano and transmission electron microscopy (TEM). Mitochondrial reporter mice (mt-Keima and mito-QC) were exposed to air or CS for 10 days. mt-Keima mice were treated with intraperitoneal injections of MSC or EXO or MSC and EXO (MSC + EXO) for 10 days. Total cell counts, differential cell counts were performed using automated cell counter and flow cytometry respectively. Further, the levels of pro-inflammatory mediators in bronchoalveolar lavage (BAL) fluid were measured using ELISA. Western blot analysis, quantitative PCR, confocal microscopy were used in the current study to determine the effects in the lungs of CS exposed mice. Seahorse flux analyzer was used to measure the oxidative-phosphorylation (OXPHOS) in the BEAS2B cells and BEAS2B - mMSC co-culture experiments. ResultsCS exposure increased the inflammatory cellular infiltrations in the lungs of the mt-Keima mice. MSC + EXO treatment showed protection compared to individual treatments (MSC or EXO alone). There were no changes in the mitophagy proteins like PINK1 and Parkin, which was also found using the mito-QC mice. CS exposure led to significant increase in the mitochondrial fission protein DRP1 and other DAMPs pathway mediators like S100A4 and S100A8, HMGB1, RAGE and AGE. MSC + EXO treatment increased the gene expression of (fusion genes) mfn1, mfn2 and opa1. Additionally, the rhot1 gene expression was increased in MSC + EXO treatment group compared to Air- and CS exposed groups. BEAS2B-mMSC co-cultures showed protective response against the CSE-altered mitochondrial respiration parameters, confirming the beneficial effect of MSC towards human bronchial lung epithelial cells. ConclusionCS affects some of early mitochondrial genes involved in the fission/fusion process, enhancing the damage response along with altered cytokine levels. MSC + EXO combination treatment showed their protective effects. MSC + EXO combination treatment may act against these early events caused by CS exposure owing to its anti-inflammatory and other mitochondrial transfer mechanisms.

Thioredoxin-1 is required for the cardioprotecive effect of sildenafil against ischaemia/reperfusion injury and mitochondrial dysfunction in mice

Sildenafil is a phosphodiesterase type 5 inhibitor which confers cardioprotection against myocardial ischaemia/reperfusion (I/R) injury. The aim of this study was to determine if Trx1 participates in cardioprotection exerted by sildenafil in an acute model of I/R, and to evaluate mitochondrial bioenergetics and cellular redox status. Langendorff-perfused hearts from wild type (WT) mice and a dominant negative (DN-Trx1) mutant of Trx1 were assigned to placebo or sildenafil (0.7 mg/kg i.p.) and subjected to 30 min of ischaemia followed by 120 min of reperfusion. WT + S showed a significant reduction of infarct size (51.2 ± 3.0% vs. 30 ± 3.0%, p < .001), an effect not observed in DN-Trx. After I/R, sildenafil preserved state 3 oxygen consumption from WT, but had a milder effect in DN-Trx1 only partially protecting state 3 values. Treatment restored respiratory control (RC) after I/R, which resulted 8% (WT) and 24% (DN-Trx1) lower than in basal conditions. After I/R, a significant increase in H2O2 production was observed both for WT and DN-Trx (WT: 1.17 ± 0.13 nmol/mg protein and DN-Trx: 1.38 ± 0.12 nmol/min mg protein). With sildenafil, values were 21% lower only in WT I/R. Treatment decreased GSSG levels both in WT and DN-Trx1. In addition, GSSG/GSH2 ratio was partially restored by sildenafil. Also, an increase in p-eNOS/eNOS even before the myocardial ischaemia was observed with sildenafil, both in WT (14%, p > .05) and in DN-Trx (35%, p < .05). Active Trx1 is required for the onset of the cardioprotective effects of sildenafil on I/R injury, together with the preservation of cellular redox balance and mitochondrial function.

Therapeutic Approaches in Mitochondrial Dysfunction, Inflammation, and Autophagy in Uremic Cachexia: Role of Aerobic Exercise.

Chronic kidney disease (CKD) causes several systemic changes, including muscular homeostasis, and eventually results in muscle atrophy. CKD-induced muscle atrophy is highly prevalent, and exercise is well known to enhance muscle function in these cases, although the exact mechanism remains unclear. Here, we aim to assess whether the protective effect of aerobic exercise in 5/6 nephrectomized (CKD) mice is associated with mitochondrial dysfunction, autophagy, or inflammation. C57BL/6J mice were randomly allocated into 3 different experimental groups: Sham, CKD, and CKD+aerobic exercise (CKD+AE). Renal function was assessed via serum creatinine and urea levels, and histological PAS and Masson staining were performed. Muscle wasting was determined based on grip strength, cross-sectional area (CSA), and MyHC protein expression. We also measured mitochondrial dysfunction in mice by assessing mtDNA, ROS, ATP production, and mitochondrial configuration. Autophagy was determined via assessments for Atg7, LC3, and SQSTM1 on western blotting. Inflammation was identified via proinflammatory cytokines and NLRP3 inflammasome components using real-time PCR and western blotting. We found that CKD mice exhibited higher BUN and creatinine levels and more severe glomerulosclerosis in the glomeruli and renal tubulointerstitial fibrosis, relative to the Sham group; all these effects were relieved by aerobic exercise. Moreover, grip strength, CSA, and MyHC protein expression were improved after 8 weeks of aerobic exercise. Furthermore, aerobic exercise significantly decreased MDA levels, increased SOD2 activity and ATP production, and improved mitochondrial configuration, relative to the CKD group. In addition, aerobic exercise downregulated the overexpression of proinflammatory cytokines and NLRP3 inflammasome components and balanced the mitochondrial biogenesis and autophagy-lysosomal system. Thus, we observed that aerobic exercise may ameliorate CKD-induced muscle wasting by improving mitochondrial dysfunction, inflammation, and autophagy-lysosomal system in uremic cachexia.

MiR‐141 inhibition protects cardiomyocytes from anoxia/reoxygenation‐induced mitochondrial dysfunction

BackgroundMitochondrial dysfunction plays an important role in ischemia/reperfusion (I/R) ‐induced myocardial injury. MicroRNAs are involved in myocardial injury after I/R. It has been reported that miR‐141 contributes to mitochondrial dysfunction in mice with diabetes. The aim of the present study is to dertmine whether the miR‐141 contributes to I/R‐induced myocardial injury and the underlying mechanism.MethodsHL‐1 cells were challenged with an anoxia/reoxygenation (A/R). miR‐141 expression in HL‐1 cells was detected by qRT‐PCR. Mitofusin‐2 (Mfn2) was assessed with Western blot. HL‐1 cellular oxygen consumption rate (OCR) was assessed with Seahorse XF24 analyzer.ResultsA/R challenge to HL‐1 cells increased miR‐141 expression and peaked at 12 hours after the reoxygenation. A/R challenge resulted in decreased mitochondrial membrane potential, OCR and ATP production of the cardiomyocytes, as well as increased LDH activity in the supernatant of the cardiomyocytes. The above changes were attenuated by transfection of the cardiomyocytes with miR‐141 inhibitor before the A/R. Overexpression of miR‐141 in the HL‐1 cell exaggerated the A/R‐induced mitochondrial dysfunction and cardiomyocyte injury. The A/R challenge to HL‐1 cells led to a decreased Mfn2 expression. Transfection of HL‐1 cells with miR‐141 mimics suppressed Mfn2 expression.ConclusionOur data indicate that miR‐141 is involved in A/R‐induced mitochondrial dysfunction by modulating Mfn2 protein expression.Support or Funding InformationThe study was supported by Natural Science Foundation of Jiangsu Province (BK20151332) and Natural Science Foundation of China (81370333).This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Apple peel polyphenols reduce mitochondrial dysfunction in mice with DSS-induced ulcerative colitis

Inflammatory bowel diseases (IBDs) are multifaceted and relapsing immune disorders, which necessitate long-term dependence on powerful drugs. As the use of natural product-based therapies has emerged as a promising intervention, the present study aimed to further characterize dried apple peel powder (DAPP) mechanisms of action and evaluate the preventive and curative effects of DAPP on mitochondrial functions in a murine model. Induction of intestinal inflammation in mice is performed by oral administration of the dextran sodium sulfate (DSS) at 2.5% for 10 days. Doses of DAPP (200 or 400 mg/kg/day) were administered by gavage for 10 days pre- and 1 day after colitis induction simultaneously with DSS treatment for a period of 10 days. The preventive (200 mg/kg/day) and therapeutic (400 mg/kg/day) doses of DAPP limited DSS-induced histological lesions, improved macroscopic parameters and attenuated clinical signs. DAPP at the same conditions reduced massive infiltration of inflammatory cells and concomitantly displayed a robust potential of counteracting inflammation and oxidative stress in DSS mice. Moreover, DAPP partially restored mitochondrial abnormalities related to size, density, redox homeostasis, fatty acid β-oxidation, ATP synthesis, apoptosis and regulatory mitochondrial transcription factors. Our findings demonstrate the preventive and therapeutic impact of DAPP on experimental colitis while underlying the role of mitochondria. They also suggest that this natural DAPP product may represent an interesting candidate for further studies on the prevention/treatment of IBD.

Ca2+ metabolic disorder and abnormal expression of cardiac troponin involved in fluoride-induced cardiomyocyte damage

Our previous study indicated that excessive fluoride (F) induces ATP5J and ATP5H proactive expression by interfering cardiomyocyte mitochondrial dysfunction in mice. This study aimed to investigate underlying mechanisms of F¯ induced damage to cardiomyocytes. A total of 100 mg/L F¯ was added to distilled water to treat Kunming mice for 70 days. Pathological and morphological changes in myocardial tissues were observed under transmission electron microscope and light microscope. Content of ATP and ATP enzyme distributed in cardiomyocytes were determined by fluorescence and ATP enzyme staining. Expression levels of troponin (Tn) C, TnI, TnT and tropomyosin (TPM) were measured by immunofluorescence, western blot, and real-time polymerase chain reaction. Contents of Ca2+ in blood, myocardial cells and faeces were also detected by confocal microscopy and ethylenediaminetetraacetic acid. Using 100 mg/L F¯ resulted in nuclaer enrichment, the myocardial fibre breakage and mitochondrial lysis. Following mitochondrial structure damage, contents of ATP and ATP enzyme significantly decreased in the fluoride group. Expression levels of TnT and TnI were significantly down-regulated, whereas that of TPM was up-regulated. Content of Ca2+ in cardiomyocytes of fluoride group visibly increased. Interestingly, contents of Ca2+ in blood and faeces decreased. These findings reveal that excessive F ingestion induces Ca2+ metabolic disorder, and an abnormal expression of cardiac Tn are involved in F-induced cardiomyocyte damage.

Combination of curcumin and ellagic acid mitigates rotenone induced locomotor, oxidative and mitochondrial deficits in mice

Objective: The present study was designed in order to explore the possible neuroprotective role of com- bination of Cur and EA against rotenone induced locomotor, oxidative and mitochondrial dysfunction in mice.

MicroRNA-709 Mediates Acute Tubular Injury through Effects on Mitochondrial Function.

Mitochondrial dysfunction has important roles in the pathogenesis of AKI, yet therapeutic approaches to improve mitochondrial function remain limited. In this study, we investigated the pathogenic role of microRNA-709 (miR-709) in mediating mitochondrial impairment and tubular cell death in AKI. In a cisplatin-induced AKI mouse model and in biopsy samples of human AKI kidney tissue, miR-709 was significantly upregulated in the proximal tubular cells (PTCs). The expression of miR-709 in the renal PTCs of patients with AKI correlated with the severity of kidney injury. In cultured mouse PTCs, overexpression of miR-709 markedly induced mitochondrial dysfunction and cell apoptosis, and inhibition of miR-709 ameliorated cisplatin-induced mitochondrial dysfunction and cell injury. Further analyses showed that mitochondrial transcriptional factor A (TFAM) is a target gene of miR-709, and genetic restoration of TFAM attenuated mitochondrial dysfunction and cell injury induced by cisplatin or miR-709 overexpression in vitro Moreover, antagonizing miR-709 with an miR-709 antagomir dramatically attenuated cisplatin-induced kidney injury and mitochondrial dysfunction in mice. Collectively, our results suggest that miR-709 has an important role in mediating cisplatin-induced AKI via negative regulation of TFAM and subsequent mitochondrial dysfunction. These findings reveal a pathogenic role of miR-709 in acute tubular injury and suggest a novel target for the treatment of AKI.

Farnesoid X receptor agonist GW4064 ameliorates lipopolysaccharide-induced ileocolitis through TLR4/MyD88 pathway related mitochondrial dysfunction in mice

Inflammatory bowel disease (IBD) is a complex and relapsing inflammatory condition of the gastro intestinal tract characterized by diarrhoea and abdominal pain. Farnesoid X receptor (FXR) plays an important role in enteroprotection and mucosal injury by regulating inflammatory responses and barrier function in the intestinal tract. Here we show the mechanisms of FXR agonist, GW4064, inhibits mucosal injury in ileum caused by lipopolysaccharides (LPS). Ileum injury was induced by intraperitoneal injection of LPS in Wild-type (WT) and FXR knockout (KO) mice. GW4064 alleviates LPS-mediated tight junction dysfunction as well as macrophage infiltration in WT mice, but not in FXR KO mice. Interesting, GW4064 suppresses NACHT, LRR and PYD domains-containing protein 3 (NALP3) inflammasome mediates tumor necrosis factor-alpha (TNF-α), interleukin (IL)-6 and IL-1β, as well as mitochondrial respiratory complexes mRNA expression in WT and FXR KO mice treated with LPS. This results demonstrated that central roles of FXR in coordinating regulation of both inflammation and mitochondrial dysfunction. We propose that GW4064 is promising therapeutic agent for treatment of ileocolitis.

LCZ696 improves cardiac function via alleviating Drp1-mediated mitochondrial dysfunction in mice with doxorubicin-induced dilated cardiomyopathy

AimsLCZ696, a novel angiotensin receptor neprilysin inhibitor, is effective in treating heart failure patients. Doxorubicin (DOX) is an effective antitumor medication but the cardiotoxicity limited its clinical use. In this study, we aimed to determine the effect of LCZ696 on DOX-induced cardiomyopathy in mice and in vitro and to explore related mechanisms focusing on fission protein dynamin-related protein 1 (Drp1). Methods and resultsIn human study, we found that myocardial fission protein Drp1 expression and its ser 616 phosphorylation were significantly increased in dilated cardiomyopathy (DCM) patients. Male Balb/c mice and H9c2 cardiomyocytes were randomized into three groups: saline, DOX, DOX plus LCZ696. Reduced cardiac function, mitochondrial morphology disturbance, reduced activity of mitochondrial respiration complex I and lowered adenosine triphosphate (ATP) content were detected post DOX stimulation in mice, which could be significantly improved by LCZ696. Fission protein Drp1 and its ser 616 phosphorylation were also increased post DOX and which could be reduced by LCZ696. In vitro, increased cardiomyocyte apoptosis, Drp1 ser 616 phosphorylation post DOX stimulation could be significantly attenuated by LCZ696 or Drp1 specific inhibitor Midivi-1. Furthermore, over-expression of Drp1 abrogated the protection effect of LCZ696 against DOX-induced cardiotoxicity in H9c2 cells. ConclusionThe protective effect of LCZ696 against DOX-induced cardiac dysfunction is at least partly associated with alleviating Drp1-mediated mitochondrial dysfunction.

Inhibition of nuclear factor-κB signal by pyrrolidine dithiocarbamate alleviates lipopolysaccharide-induced acute lung injury.

This study mainly studied the effect of inhibition of nuclear factor-κB (NF-κB) signal by pyrrolidine dithiocarbamate (PDTC) on lipopolysaccharide (LPS)-induced inflammatory response, oxidative stress, and mitochondrial dysfunction in a murine acute lung injury model. The results showed that LPS exposure activated NF-κB and its upstream proteins and caused lung inflammation, oxidative stress, and mitochondrial dysfunction in mice. While inhibition of NF-κB by PDTC adminstration alleviated LPS-induced generation of lymphocytes, IL-1β, and TNF-α. Malondialdehyde, a common oxidative product, was markedly reduced after PDTC treatment in LPS-challenged mice. Furthermore, PDTC alleviated LPS-induced mitochondrial dysfunction via improving ATP synthesis and uncoupling protein 2 expression. In conclusion, inhibition of NF-κB by PDTC alleviated LPS-induced acute lung injury via maintaining inflammatory status, oxidative balance, and mitochondrial function in mice.

Hepatic Effects of Pharmacological Doses of Hydroxy-Cobalamin[c-lactam] in Mice.

The vitamin B12 analog hydroxy-cobalamin[c-lactam] (HCCL) impairs hepatic mitochondrial protein synthesis and function of the electron transport chain in rats. We aimed to establish an in vivo model for mitochondrial dysfunction in mice, which could be used to investigate hepatotoxicity of mitochondrial toxicants. In a first step, we performed a dose-finding study in mice treated with HCCL 0.4 mg/kg and 4 mg/kg i.p. for two to four weeks. The plasma methylmalonate concentration was strongly increased at 4 mg/kg starting at three weeks of treatment. We subsequently treated mice daily with 4 mg/kg HCCL i.p. for three weeks and characterized liver function and histology as well as liver mitochondrial function. We found an increase in liver weight in HCCL-treated mice, which was paralleled by hepatocellular accumulation of triglycerides. In liver homogenate of HCCL-treated mice, the complex I activity of the electron transport chain was reduced, most likely explaining hepatocellular triglyceride accumulation. The activity of CPT1 was not affected by methylmalonyl-CoA in isolated liver mitochondria. Despite impaired complex I activity, mitochondrial superoxide anion production was not increased and the hepatocellular glutathione (GSH) pool was maintained. Finally, the mitochondrial DNA content was not altered with HCCL treatment. In conclusion, treatment of mice with HCCL is associated with increased liver weight explained by hepatocellular triglyceride accumulation. Hepatocellular fat accumulation is most likely a consequence of impaired activity of the mitochondrial electron transport chain. The impairment of complex I activity is not strong enough to result in ROS accumulation and reduction of the GSH stores.

Neuroprotective effect of curcumin as evinced by abrogation of rotenone-induced motor deficits, oxidative and mitochondrial dysfunctions in mouse model of Parkinson's disease

Curcumin, a natural polyphenolic compound extracted from rhizomes of Curcuma longa (turmeric), a plant in the ginger family (Zingiberaceae) has been used worldwide and extensively in Southeast Asia. Curcumin exhibited numerous biological and pharmacological activities including potent antioxidant, cardiovascular disease, anticancer, anti-inflammatory effects and neurodegenerative disorders in cell cultures and animal models. Hence, the present study was designed in order to explore the possible neuroprotective role of curcumin against rotenone induced cognitive impairment, oxidative and mitochondrial dysfunction in mice. Chronic administration of rotenone (1mg/kg i.p.) for a period of three weeks significantly impaired cognitive function (actophotometer, rotarod and open field test), oxidative defense (increased lipid peroxidation, nitrite concentration and decreased activity of superoxide dismutase, catalase and reduced glutathione level) and mitochondrial complex (II and III) enzymes activities as compared to normal control group. Three weeks of curcumin (50, 100 and 200mg/kg, p.o.) treatment significantly improved behavioral alterations, oxidative damage and mitochondrial enzyme complex activities as compared to negative control (rotenone treated) group. Curcumin treated mice also mitigated enhanced acetylcholine esterase enzyme level as compared to negative control group. We found that curcumin restored motor deficits and enhanced the activities of antioxidant enzymes suggesting its antioxidant potential in vivo. The findings of the present study conclude neuroprotective role of curcumin against rotenone induced Parkinson's in mice and offer strong justification for the therapeutic prospective of this compound in the management of PD.

Loss of the RNA-binding protein TACO1 causes late-onset mitochondrial dysfunction in mice.

The recognition and translation of mammalian mitochondrial mRNAs are poorly understood. To gain further insights into these processes in vivo, we characterized mice with a missense mutation that causes loss of the translational activator of cytochrome oxidase subunit I (TACO1). We report that TACO1 is not required for embryonic survival, although the mutant mice have substantially reduced COXI protein, causing an isolated complex IV deficiency. We show that TACO1 specifically binds the mt-Co1 mRNA and is required for translation of COXI through its association with the mitochondrial ribosome. We determined the atomic structure of TACO1, revealing three domains in the shape of a hook with a tunnel between domains 1 and 3. Mutations in the positively charged domain 1 reduce RNA binding by TACO1. The Taco1 mutant mice develop a late-onset visual impairment, motor dysfunction and cardiac hypertrophy and thus provide a useful model for future treatment trials for mitochondrial disease.

Anthocyanins Improved Mitochondrial Dysfunction in Mice of Non‐alcoholic Fatty Liver Disease Induced by High Fat Diet

Recent studies indicate that mitochondrial dysfunction plays a critical role in the pathogenesis of non‐alcoholic fatty liver disease (NAFLD. The goal of this study is to investigate whether anthocyanins (ACNs) from bilberries and blackcurrants possess a protective effect on mitochondrial dysfunction and eventually contribute to attenuation of NAFLD in mice induced by feeding a high fat (HF) diet. Twenty‐four male C57BL6/J mice were randomly divided into three groups with different diets respectively for sixteen weeks: the control group was fed a low‐fat diet and the other two groups were fed a HF diet with ACNs or not. Our results illustrated that ACNs administration at a dosage of 100 mg in 1 kg diet significantly inhibited HF diet‐induced hepatic steatosis and inflammatory cell infiltration. In addition, increase of mitochondrial swelling, decrease of mitochondrial content and damage of mitochondrial biogenesis, oxidative phosphorylation and β‐oxidation were observed in mice fed with a HF diet, which were significantly normalized through ACNs supplementation. This appears to be attributed to activation of phosphorylated AMP‐activated protein kinase (p‐AMPK) and its downstream peroxisome proliferator‐activated receptor‐gamma coactivator‐1α (PGC‐1α). Our work presents the beneficial effects of ACNs on mitochondrial dysfunction in HF‐induced NAFLD mice by promoting activation of AMPK/PGC1α signaling axis, signifying that ACNs may be a useful nutrient for the treatment of NAFLD.All animal procedures were approved by the Animal Care and Protection Committee of Sun Yat‐Sen University (2013–10).Support or Funding InformationThis research was funded by grants from the National Basic Research Program (973 Program, 2012CB517506) and the National Nature Science Foundation (81172655, 81372994).

C-phycocyanin prevents cisplatin-induced mitochondrial dysfunction and oxidative stress

The potential of C-phycocyanin (C-PC) to prevent cisplatin (CP)-induced kidney mitochondrial dysfunction was determined in CD-1 male mice. The CP-induced mitochondrial dysfunction was characterized by ultrastructural abnormalities and by decrease in the following parameters in isolated kidney mitochondria: adenosine diphosphate (ADP)-induced oxygen consumption (state 3), respiratory control ratio, ADP/oxygen (ADP/O) ratio, adenosine triphosphate synthesis, membrane potential, calcium retention, glutathione (GSH) content, and activity of respiratory complex I, aconitase, catalase, and GSH peroxidase. These mitochondria also showed increase in hydrogen peroxide production, malondialdehyde, and 3-nitrotyrosine protein adducts content. The above-described changes, as well as CP-induced nephrotoxicity, were attenuated in mice pretreated with a single injection of C-PC. Our data suggest that the attenuation of mitochondrial abnormalities is involved in the protective effect of C-PC against CP-induced nephrotoxicity. This is the first demonstration that C-PC pretreatment prevents CP-induced mitochondrial dysfunction in mice.

Naringin Improves Neuronal Insulin Signaling, Brain Mitochondrial Function, and Cognitive Function in High-Fat Diet-Induced Obese Mice.

The epidemic and experimental studies have confirmed that the obesity induced by high-fat diet not only caused neuronal insulin resistance, but also induced brain mitochondrial dysfunction as well as learning impairment in mice. Naringin has been reported to posses biological functions which are beneficial to human cognitions, but its protective effects on HFD-induced cognitive deficits and underlying mechanisms have not been well characterized. In the present study Male C57BL/6 J mice were fed either a control or high-fat diet for 20 weeks and then randomized into four groups treated with their respective diets including control diet, control diet + naringin, high-fat diet (HFD), and high-fat diet + naringin (HFDN). The behavioral performance was assessed by using novel object recognition test and Morris water maze test. Hippocampal mitochondrial parameters were analyzed. Then the protein levels of insulin signaling pathway and the AMP-activated protein kinase (AMPK) in the hippocampus were detected by Western blot method. Our results showed that oral administration of naringin significantly improved the learning and memory abilities as evidenced by increasing recognition index by 52.5% in the novel object recognition test and inducing a 1.05-fold increase in the crossing-target number in the probe test, and ameliorated mitochondrial dysfunction in mice caused by HFD consumption. Moreover, naringin significantly enhanced insulin signaling pathway as indicated by a 34.5% increase in the expression levels of IRS-1, a 47.8% decrease in the p-IRS-1, a 1.43-fold increase in the p-Akt, and a 1.89-fold increase in the p-GSK-3β in the hippocampus of the HFDN mice versus HFD mice. Furthermore, the AMPK activity significantly increased in the naringin-treated (100 mg kg(-1) d(-1)) group. These findings suggest that an enhancement in insulin signaling and a decrease in mitochondrial dysfunction through the activation of AMPK may be one of the mechanisms that naringin improves cognitive functions in HFD-induced obese mice.

Toxoplasma gondii isolate with genotype Chinese 1 triggers trophoblast apoptosis through oxidative stress and mitochondrial dysfunction in mice

Congenital toxoplasmosis may result in abortion, severe mental retardation and neurologic damage in the offspring. Placental damage is considered as the key event in this disease. Here we show that maternal infection with Toxoplasma gondii Wh3 isolate of genotype Chinese 1, which is predominantly prevalent in China, induced trophoblast apoptosis of pregnant mouse. PCR array analysis of 84 key genes in the biogenesis and functions of mouse mitochondrion revealed that ten genes were up-regulated at least 2-fold in the Wh3 infection group, compared with those in the control. The elevated levels of reactive oxygen species (ROS), malondialdehyde (MDA) and 8-hydroxydeoxyguanosine (8-OHdG), as well as the decreased glutathione (GSH), were observed in the infected mice. The mRNA levels of NADPH oxidase 1 and glutathione peroxidase 6 (GPx6) were significantly increased. The production of excessive ROS was NADPH oxidase-dependent, which contributed to mitochondrial structural damage and mitochondrial dysfunction in placentas, followed by the cleavage of caspase-9 and caspase-3, and finally resulted in apoptosis of trophoblasts. All the above-mentioned phenomena were inhibited by pretreatment with the antioxidant of N-acetylcysteine (NAC). Taken together, we concluded that Wh3 infection during pregnancy may contribute to trophoblast apoptosis by oxidative stress-induced mitochondrial dysfunction and activation of the downstream signaling pathway.

Correction: Tempol, a Superoxide Dismutase Mimetic Agent, Ameliorates Cisplatin-Induced Nephrotoxicity through Alleviation of Mitochondrial Dysfunction in Mice

Correction: Tempol, a Superoxide Dismutase Mimetic Agent, Ameliorates Cisplatin-Induced Nephrotoxicity through Alleviation of Mitochondrial Dysfunction in Mice

Abstract 12622: Western Diet for One Month Impairs Myocardial Energetics and Both Systolic and Diastolic Pump Function in the Mouse Heart

Background and Significance: Metabolic heart disease(MHD) is common in patients with obesity, type 2 diabetes and/or metabolic syndrome. We found cardiac mitochondrial dysfunction in mice with obesity-related MHD due to consumption of a high fat high sucrose (HFHS) diet. The effects of diet-induced obesity on cardiac energetics and pump function in the intact organ are largely unknown. Hypothesis: We tested the hypothesis that cardiac mitochondrial dysfunction due to HFHS diet for one month impairs energetic and contractile reserve in the intact heart. Methods and Results: Mice were fed a HFHS or control diet (CD) for 1 month. In isolated cardiac mitochondria from HFHS-fed mice (vs. CD) the maximal rate of ATP synthesis was decreased for complex I (down by 42%; p&lt;0.05) and II (down by 37%; p&lt;0.05) substrates. We measured myocardial energetics in isolated perfused hearts using 31P NMR spectroscopy at baseline (450 bpm, 2 mM Ca++) and high workload (600 bpm, 4 mM Ca++) in HFHS (n=7) and CD (n=8) hearts. In HFHS-fed hearts, myocardial ATP concentration was the same at baseline (10.5±0.4 vs 10.4±0.5 mM) and high workload (7.4±0.9 vs. 7.5±0.5 mM) as that of CD hearts. However, in HFHS-fed hearts the concentration of phosphocreatine, which reflects energy reserve, was decreased at baseline (13±0.7 vs. 17.5±0.8 mM; p&lt;0.01) and decreased further at high workload (down to 7.3±0.7; p&lt;0.01 vs. baseline and p&lt;0.01 vs. CD at 10.5±0.4 mM) - indicating a mismatch between ATP production and utilization. In HFHS hearts, the diastolic pressure-volume relationship was shifted upward and leftward at baseline, indicative of diastolic dysfunction. In HFHS hearts, baseline systolic function was preserved (rate pressure product 41,600±2,200 vs. 41,000±2,000 mmHg/min), but was decreased at high workload (54,800±7,200 vs. 85,300±4,300 mmHg/min; p&lt;0.01 vs. CD), reflecting an impaired contractile reserve. Conclusion: Consumption of a HFHS diet for one month causes cardiac mitochondrial dysfunction with reduced ATP synthesis leading to impaired energetic reserve in the intact heart. Diastolic dysfunction at rest and the impaired ability to increase systolic function with increased work demands may result from impaired energetics in MHD.