Mfn2 mRNA Research Articles

The suppressive effects of crocin from saffron on allergic airway inflammation through Drp1/Nfr1/Mfn2/Pgc1-alpha signaling pathway in mice

Ethnopharmacological relevanceSaffron is derived from the dried stigmas of Crocus sativus L., which was considered by ancient nations for food and medicinal purposes. In traditional medicine, the therapeutic use of Crocus sativus includes antispasmodic, antitussive and expectorant. Aim of the studyMitochondrial fusion, fission, biogenesis, and mitophagy are essential processes for maintaining mitochondrial dynamics in response to cellular stress. The primary objective of this research was to examine how crocin affected the levels of important mitochondrial regulators, including Drp1, Pgc1α, Nrf1, and Mfn2, in the lung tissue of ovalbumin-sensitized mice. Materials and methodsA total of fifty male BALB/C mice were randomly assigned to five unique groups (n = 10 for each group), including the control group, ovalbumin-sensitized group (OVA), OVA group treated with 30 mg/kg of crocin, OVA group treated with 60 mg/kg of crocin, and OVA group treated with 1 mg/kg of dexamethasone. Post-sensitization and ovalbumin challenge, mice lung tissues were evaluated for the expression of Drp1, Pgc1α, Nrf1, and Mfn2 mRNA levels using real-time PCR as well as histopathological assessments. ResultsIn the OVA group, there was a significant elevated in inflammatory cells such as eosinophils, neutrophils, macrophages, and lymphocytes; however, crocin (both concentrations) and dexamethasone intervention showed significant inhibitory effects (P < 0.01 to P < 0.001). Moreover, an increase in the expression of Drp1, Pgc1α, and Nrf1 levels was seen in the OVA group, while crocin and dexamethasone showed protective benefits (P < 0.05 to P < 0.001). Furthermore, the levels of Mfn2 were reduced in the lung tissue of mice exposed to ovalbumin, but this decrease was reversed by crocin 60 (P < 0.05) and dexamethasone treatment (P < 0.001). ConclusionIn mice with OVA sensitization, the balance of mitochondrial dynamics in lung tissue was disrupted, but intervention of crocin identified to have a protective effect.

MiR-373-3p promotes aerobic glycolysis in colon cancer cells by targeting MFN2.

MicroRNAs (miRNAs) are implicated in the development of cancers and may serve as potential targets for therapy. However, the functions and underlying mechanisms of miRNAs in cancers are not well understood. This work aims to study the role of miR-373-3p in colon cancer cells. We find that the expression of miR-373-3p mimics promotes and the miR-373-3p inhibitor suppresses aerobic glycolysis and proliferation of colon cancer cells. Mechanistically, miR-373-3p inhibits the expression of MFN2, a gene that is known to suppress glycolysis, which leads to the activation of glycolysis and eventually the proliferation of cells. In a nude mouse tumor model, the expression of miR-373-3p in colon cancer cells promotes tumor growth by enhancing lactate formation, which is inhibited by the co-expression of MFN2 in the cells. Administration of the miR-373-3p antagomir blunts in vivo tumor growth by decreasing lactate production. In addition, in human colon cancers, the expression levels of miR-373-3p are increased, while those of MFN2 mRNA are decreased, and the increase of miR-373-3p is associated with the decrease of MFN2 mRNA. Our results reveal a previously unknown function and underlying mechanism of miR-373-3p in the regulation of glycolysis and proliferation in cancer cells and underscore the potential of targeting miR-373-3p for colon cancer treatment.

Pharmacological Activation of AMPK Prevents Drp1-mediated Mitochondrial Fission and Alleviates Hepatic Steatosis In vitro.

The incidence of non-alcoholic fatty liver disease (NAFLD) is increasing worldwide. Adenosine monophosphate-activated protein kinase (AMPK) activation is beneficial for NAFLD treatment. Recent studies show the excessive fission of mitochondria during NAFLD progression, so targeting mitochondria dynamics may be a possible target for NAFLD. Still, little is known about whether AMPK regulates mitochondrial dynamics in hepar. This study investigated whether AMPK activation alleviates hepatic steatosis by regulating mitochondrial dynamics mediated by GTPase dynamin-related protein 1 (Drp1). Human hepatocyte line L-02 cells were cultured and subjected to palmitic acid (PA) treatment for 24 h to establish a hepatic steatosis model in vitro, which was pre-treated with different tool drugs. Hepatocyte function, hepatocyte lipid content, mitochondrial reactive oxygen species (ROS) production, and mitochondrial membrane potential (MMP) were examined. The expression levels of genes and proteins associated with mitochondrial dynamics were assessed using reverse transcription-quantitative PCR and western blotting. The results indicated that 5-Aminoimidazole-4-carboxamide 1-β-D-ribofuranoside (AICAR), an AMPK activator, improved hepatocyte function, as demonstrated by decreased alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activity (P<0.05 or P<0.01). In addition, AICAR decreased total cholesterol (TC) and triglyceride (TG) content and lipid deposition in hepatocytes (P<0.01); decreased ROS production; improved MMP (P<0.01); reduced fission-1 (Fis1) and mitochondrial fission factor (Mff) mRNA expression; and downregulated p-Drp1 (Ser 616) protein expression. In contrast, AICAR increased mitochondrial fusion factor mitofusin-1 (Mfn1) and mitofusin-2 (Mfn2) mRNA expression and upregulated p-Drp1 (Ser 637) protein expression. Mdivi-1, a Drp-1 inhibitor, was used to confirm whether mitochondrial dynamics regulated by Drp1-mediated the role of AICAR. Similar to AICAR, Mdivi-1 improved hepatocyte function and MMP significantly, decreased ROS production and lipid deposition, downregulated Fis1 and Mff mRNA expression, downregulated p-Drp1 (Ser 616) protein expression, and enhanced Mfn1 and Mfn2 mRNA and p-Drp1 (Ser 637) protein expression. However, Compound C, an AMPKspecific inhibitor, had less impact on the protective effect of Mdivi-1. The results demonstrated that AMPK activation has a protective effect on hepatic steatosis in vitro, largely dependent on the inhibition of Drp1-mediated mitochondrial fission.

ShenQiWan ameliorates renal injury in type 2 diabetic mice by modulating mitochondrial fusion and endoplasmic reticulum stress.

Background: ShenQiWan is commonly used in traditional Chinese medicine for the treatment of diabetic nephropathy, which is closely related to mitochondrial fusion and endoplasmic reticulum stress. This study aimed to investigate the intervention effect and molecular mechanisms of ShenQiWan on renal injury in KKAy mice. Methods: C57BL/6J mice (11weeks old) were fed a regular diet upon arrival, while KKAy mice (11weeks old) were fed a high-fat diet upon arrival. At 12weeks of age, KKAy mice with random blood glucose ≥13.9mmol/L were identified as diabetic mice and randomly divided into the model group (n = 30) and the treatment group (n = 30), while C57BL/6J mice of 12weeks old (n = 30) served as the control group. The treatment group received daily aqueous decoction of ShenQiWan (13.5g/kg), while the control group and model group received daily equal amounts of saline from 12weeks old to 24weeks old. The general status of mice was observed regularly, and fasting blood glucose and 24-hour urine microalbumin were measured. Ten mice were euthanized in each group at the age of 16, 20, and 24weeks, serum samples were used for biochemical indexes and kidney tissues were used for morphological studies. GRP78, OPA1, MFN1, MFN2 mRNA and protein expression were detected by Real-time PCR, immunohistochemistry and Western blot. Results: The mice in the model group exhibited symptoms of lethargy, slow movement, obesity, polyuria and proteinuria. Morphological observation revealed pathological changes, including thickening of the glomerular basement membrane and interstitial fibrosis. After treatment with ShenQiWan, the fasting blood glucose level of KKAy mice was significantly reduced, urinary albuminuria was decreased, serum biochemical indexes were improved, renal tissue pathological changes were significantly alleviated. The results also showed a significant reduction in the expression of endoplasmic reticulum stress-related factor GRP78 and an increase in the expression of mitochondrial fusion-related factors OPA1, MFN1 and MFN2 after treatment with ShenQiWan. Conclusion: ShenQiWan can protect diabetic mice from renal damage by modulating mitochondrial fusion and alleviating endoplasmic reticulum stress, exerting its protective effects.

DNA Methylation-Mediated Mfn2 Gene Regulation in the Brain: A Role in Brain Trauma-Induced Mitochondrial Dysfunction and Memory Deficits.

Repeated mild traumatic brain injuries (rMTBI) affect mitochondrial homeostasis in the brain. However, mechanisms of long-lasting neurobehavioral effects of rMTBI are largely unknown. Mitofusin 2 (Mfn2) is a critical component of tethering complexes in mitochondria-associated membranes (MAMs) and thereby plays a pivotal role in mitochondrial functions. Herein, we investigated the implications of DNA methylation in the Mfn2 gene regulation, and its consequences on mitochondrial dysfunction in the hippocampus after rMTBI. rMTBI dramatically reduced the mitochondrial mass, which was concomitant with decrease in Mfn2 mRNA and protein levels. DNA hypermethylation at the Mfn2 gene promoter was observed post 30days of rMTBI. The treatment of 5-Azacytidine, a pan DNA methyltransferase inhibitor, normalized DNA methylation levels at Mfn2 promoter, which further resulted into restoration of Mfn2 function. The normalization of Mfn2 function was well correlated with recovery in memory deficits in rMTBI-exposed rats. Since, glutamate excitotoxicity serves as a primary insult after TBI, we employed in vitro model of glutamate excitotoxicity in human neuronal cell line SH-SY5Y to investigate the causal epigenetic mechanisms of Mfn2 gene regulation. The glutamate excitotoxicity reduced Mfn2 levels via DNA hypermethylation at Mfn2 promoter. Loss of Mfn2 caused significant surge in cellular and mitochondrial ROS levels with lowered mitochondrial membrane potential in cultured SH-SY5Y cells. Like rMTBI, these consequences of glutamate excitotoxicity were also prevented by 5-AzaC pre-treatment. Therefore, DNA methylation serves as a vital epigenetic mechanism involved in Mfn2 expression in the brain; and this Mfn2 gene regulation may play a pivotal role in rMTBI-induced persistent cognitive deficits. Closed head weight drop injury method was employed to induce repeated mild traumatic brain (rMTBI) in jury in adult, male Wistar rats. rMTBI causes hyper DNA methylation at the Mfn2 promoter and lowers the Mfn2 expression triggering mitochondrial dysfunction. However, the treatment of 5-azacytidine normalizes DNA methylation at the Mfn2 promoter and restores mitochondrial function.

Mitochondrial Features and Expressions of MFN2 and DRP1 during Spermiogenesis in Phascolosoma esculenta.

Mitochondria can fuse or divide, a phenomenon known as mitochondrial dynamics, and their distribution within a cell changes according to the physiological status of the cell. However, the functions of mitochondrial dynamics during spermatogenesis in animals other than mammals and fruit flies are poorly understood. In this study, we analyzed mitochondrial distribution and morphology during spermiogenesis in Sipuncula (Phascolosoma esculenta) and investigated the expression dynamics of mitochondrial fusion-related protein MFN2 and fission-related protein DRP1 during spermiogenesis. The mitochondria, which were elliptic with abundant lamellar cristae, were mainly localized near the nucleus and distributed unilaterally in cells during most stages of spermiogenesis. Their major axis length, average diameter, cross-sectional area, and volume are significantly changed during spermiogenesis. mfn2 and drp1 mRNA and proteins were most highly expressed in coelomic fluid, a spermatid development site for male P. esculenta, and highly expressed in the breeding stage compared to in the non-breeding stage. MFN2 and DRP1 expression levels were higher in components with many spermatids than in spermatid-free components. Immunofluorescence revealed that MFN2 and DRP1 were consistently expressed and that MFN2 co-localizes with mitochondria during spermiogenesis. The results provide evidence for an important role of mitochondrial dynamics during spermiogenesis from morphology and molecular biology in P. esculenta, broadening insights into the role of mitochondrial dynamics in animal spermiogenesis.

Comprehensive analysis of MFN2 as a prognostic biomarker associated with immune cell infiltration in renal clear cell carcinoma

BackgroundTreatment of advanced kidney renal clear cell carcinoma (KIRC) remains challenging in clinic. The functional role and prognostic significance of MFN2 in KIRC are still unclear. MethodsIn this study, we first performed a bioinformatic analysis to determine the expression level and prognostic value of MFN2 in KIRC using The Cancer Genome Atlas (TCGA) dataset, and then validated the MFN2 mRNA expression in our cohort of clinical tissue samples and cell lines of KIRC via RT-qPCR. Cox regression model was used to identify the independent prognostic factors. A nomogram was constructed to predict the prognosis of KIRC patients. Gene set enrichment analysis (GSEA) was performed to predict the involved functional pathways of MFN2 co-expressed genes. The association between MFN2 expression level and immune cell infiltration was assessed using the TIMER and the TIDISB databases. In addition, cell proliferation and migration abilities of two KIRC cell lines with MFN2 overexpression were evaluated by MTS and wound healing assays, respectively. ResultsDownregulation of MFN2 was observed in KIRC tissues and cell lines compared to the normal controls. Kaplan-Meier curve analysis indicated an inferior survival outcomes in KIRC patients with lower MFN2 expression, uncovering the tumor-suppressive role of MFN2 in KIRC. Cox regression results showed that higher MFN2 expression was one of the independent protective factors in KIRC. Besides, function predictive analysis revealed that MFN2 co-expressed genes were enriched in the biological processes of energy metabolism and autophagy. Moreover, MFN2 expression was observed to be significantly associated with immune cell infiltration and a variety of markers of tumor infiltrating immune cells (TIICs) including multiple immune checkpoints in KIRC tissues. Finally, MFN2 overexpression significantly inhibited cell proliferation and migration abilities of two KIRC cell lines examined. ConclusionGenerally, our data suggested that MFN2 may serve as a potential prognostic biomarker and therapeutic target in KIRC.

Treatment of Pelvic Organ Prolapse by the Downregulation of the Expression of Mitofusin 2 in Uterosacral Ligament Tissue via Mesenchymal Stem Cells.

Background: The relationship between pelvic organ prolapse (POP), an aging-related disease, and the senescence-related protein mitofusin 2 (Mfn2) has rarely been studied. The aim of the present study was to explore the therapeutic effects of the downregulation of Mfn2 expression by stem cells on POP through animal experiments. Methods: First, a rat POP model was constructed by ovariectomy and traction. The rats in the non-pelvic organ prolapse (NPOP) and POP groups were divided into four groups for negative controls (N1–N4, N1: NPOP-normal saline; N2: NPOP-untransfected stem cells; N3: NPOP-short hairpin negative control (NPOP-sh-NC); N4: NPOP-short hairpin-Mfn2 (NPOP-sh-Mfn2)), and four groups for prolapse (P1–P4, P1: POP-normal saline; P2: POP-untransfected stem cells; P3: POP-sh-NC; P4: POP-sh-Mfn2), respectively. Stem cells were then cultured and isolated. The expression of Mfn2 was inhibited by lentivirus transfection, and the stem cells were injected into the uterosacral ligament of the rats in each group. The expression levels of Mfn2 and procollagen 1A1/1A2/3A1 in the uterosacral ligaments of the rats were observed at 0, 7, 14, and 21 days after injection. Results: Compared to the rats in the NPOP group, the POP rats had significant prolapse. The Mfn2 expression in the uterosacral ligaments of the POP rats was significantly increased (p < 0.05, all), and the expression of procollagen 1A1/1A2/3A1 was significantly decreased (p < 0.001, all). The POP rat model maintained the same trend after 21 days (without stem cell injection). At day 14, compared to the rats in the N1 group, the Mfn2 expression in the uterosacral ligament of the rats in the N4 group was significantly decreased (p < 0.05, all), and the expression of procollagens was significantly increased (p < 0.05, all). Similarly, compared to the rats in the P1 group, the Mfn2 expression in the uterosacral ligament of the rats in the P4 group was significantly decreased (p < 0.05, all), and the expression of procollagens was significantly increased (p < 0.05, all). Similarly, on day 21, the Mfn2 mRNA and protein expression in the uterosacral ligament of the POP and NPOP rats was significantly decreased (p < 0.05, all), and the expression of procollagens was significantly increased (p < 0.05, all) in the rats in the sh-Mfn2 group (N4, P4) compared to the rats in the saline group (N1, P1). Conclusions: The downregulation of Mfn2 expression by stem cells decreased the expression of Mfn2 and increased the expression of procollagen1A1/1A2/3A1 in the uterosacral ligament of the POP rats; this effect was significant 14–21 days after the injection. Thus, Mfn2 may be a new target for POP control.

LncRNA NEAT1 ameliorate ischemic stroke via promoting Mfn2 expression through binding to Nova and activates Sirt3.

Recent studies revealed that long non-coding RNAs (lncRNAs) have significant roles in regulating the pathogenesis of ischemia stroke, and oxygen-glucose deprivation/reoxygenation (OGD/R)-induced cell apoptosis. Aberrant expression of NEAT1 was found after the injury of ischemia-reperfusion, but the mechanism was not fully understood. The expression of NEAT1 and Mfn2 were detected in BV-2 and N2a cell with or without OGD/R-induced by qRT-PCR. Inflammatory cytokines secretion was detected by enzyme-linked immunosorbent assay (ELISA). The oxidative stress was evaluated by the examination of ROS, MDA and SOD levels. Flow cytometry and apoptosis marker detection by western blot were performed to examined apoptosis. The expression of NEAT1 and Mfn2 were decreased in OGD/R-induced cell model. Overexpression of NEAT1 or Mfn2 reduced oxidative stress and apoptosis by OGD/R-induced in neuronal cells, while knockdown of Sirt3 reversed the protective effect of NEAT1 and Mfn2. NEAT1 stabilized Mfn2 mRNA via recruiting Nova. NEAT1 alleviates the oxidative stress and apoptosis by OGD/R-induced via activating Sirt3. LncRNA NEAT1 stabilizes Mfn2 mRNA via recruiting Nova, therefore increase the expression of Mfn2 and alleviates ischemia-reperfusion induced oxidative stress and apoptosis via Mfn2/Sirt3 pathway.

Effects of vibration on the expression of mitochondrial fusion and fission genes and ultrastructure of skeletal muscle in rabbits

Objective: To study the effects of vibration on the expression of mitochondrial fusion and fission genes and ultrastructure of skeletal muscle in rabbits. Methods: Thirty-two 3.5-month-old New Zealand rabbits were randomly divided into low-intensity group, medium-intensity group, high-intensity group and control group, with 8 rabbits in each group. The rabbits in the experimental group were subjected to hind limb vibration load test for 45 days. The vibration intensity of the high intensity group was 12.26 m/s(2), the medium intensity group was 6.13 m/s(2), and the low intensity group was 3.02 m/s(2) according to the effective value of weighted acceleration[a(hw (4))] for 4 hours of equal energy frequency. The control group was exposed to noise only in the same experimental environment as the medium-intensity group. The noise levels of each group were measured during the vibration load experiment. After the test, the mRNA expression of mitochondrial fusion gene (Mfn1/Mfn2) and fission gene (Fis1, Drp1) by RT-PCR in the skeletal muscles were measured and the ultrastructure of the skeletal muscles were observed in high intensity group. Results: The mRNA expression of mitochondrial in the skeletal muscle tissues of control group, low intensity group, medium intensity group and high intensity group were Mfn1: 3.25±1.36, 3.85±1.90, 4.53±2.31 and 11.63±7.68; Mfn2: 0.68±0.25, 1.02±0.40, 0.94±0.33 and 1.40±0.45; Fis1: 1.05±0.62, 1.15±0.59, 1.53±1.06 and 2.46±1.51 and Drp1: 3.72±1.76, 2.91±1.63, 3.27±2.01 and 4.21±2.46, respectively. Compared with the control group, the expressions of Mfn1 mRNA, Mfn2 mRNA and Fis1 mRNA in the high-intensity group increased significantly (P<0.05) , and the expressions of Mfn2 mRNA in the medium-intensity group and the low-intensity group increased significantly (P<0.05) . Compared with the control group, the ultrastructure of skeletal muscle of high intensity group showed mitochondrial focal accumulation, cristae membrane damage, vacuole-like changes; Z-line irregularity of muscle fibers, and deficiency of sarcomere. Conclusion: Vibration must be lead to the abnormal mitochondrial morphology and structure and the disorder of energy metabolism due to the expression imbalance of mitochondrial fusion and fission genes in skeletal muscles of rabbits, which may be an important target of vibration-induced skeletal muscle injury.

Geranylgeraniol Supplementation Mitigates Soleus Muscle Atrophy via Changes in Mitochondrial Quality in Diabetic Rats.

With diabetes, skeletal muscle mitochondrial quality (fusion, fission & mitophagy) and muscle mass are compromised. Geranylgeraniol (GGOH) can prevent mitochondrial damage, inflammation, and improve muscle health; however, the effect of GGOH on a diabetic model is not known. This study aimed to determine the effect of GGOH on mitochondrial quality and muscle mass in diabetic rats. Sprague-Dawley rats were divided into three groups: regular diet (CON; n=7), high-fat-diet with 35 mg/kg body weight of streptozotocin (STZ) (HFD; n=7), and HFD/STZ with 800 mg/kg of GGOH (GG; n=7) for a total of 8 weeks. At the end of the study, soleus and gastrocnemius muscles were collected and analyzed for gene and protein expression of OPA1, MFN2, DRP1, p-DRP, LC3AB, PINK1, Parkin, SOD2, NF-[Formula: see text]B, IL-6, TNF-α, and IL-1β. Additionally, the cross-sectional area (CSA) of soleus muscles was analyzed. In soleus, HFD group had significantly higher IL-1β and lower LC3A, MFN2, DRP1, and SOD2 mRNA expression compared to CON group. The GG group had higher PINK1 mRNA expression than the HFD group. Additionally, the GG group had lower LC3B and DRP1 protein than the HFD group and lower LC3A and MFN2 protein than the HFD and CON groups. Lastly, HFD and GG groups had a smaller CSA than CON group, whereas GG had a greater CSA than HFD. GGOH supplementation could prevent mitochondrial fragmentation and potentially decrease the demand for mitochondrial fusion. Additionally, autophagosome degradation occurred at a greater rate than formation, indicating increased clearance of damaged organelles. Improved mitochondrial quality could potentially rescue muscle CSA in diabetic rats with GGOH supplementation.

Hexavalent Chromium Causes Apoptosis and Autophagy by Inducing Mitochondrial Dysfunction and Oxidative Stress in Broiler Cardiomyocytes.

Hexavalent chromium (Cr(VI)) is a common environmental pollutant, which has a strong toxic effect on humans and animals. However, the cardiac toxicity of Cr(VI) in broilers remains to be explored. The development of heart disease is often linked to mitochondrial dysfunction especially exposure to toxic substances. In order to investigate the role of mitochondrial dysfunction in apoptosis and autophagy of broiler cardiomyocytes induced by hexavalent chromium, broiler cardiomyocytes were cultured in potassium dichromate of 0mM, 16mM, and 32mM medium for 24h. The results showed that, compared with the control group, reactive oxygen species (ROS) and apoptosis rate in the Cr(VI) treatment group increased in a dose-dependent manner, the mRNA levels of apoptosis-related genes Bax and p53 were significantly increased, and the mRNA level of Bcl-2 was significantly decreased. Compared with the control group, the mRNA level of autophagy-related genes (LC3-I, LC3-II, and Beclin1) in the Cr(VI) treatment group was significantly increased, the mRNA level of mTOR was significantly decreased, and the protein level of p62/SQSTM1 was significantly decreased. The protein level of Beclin1 and the ratio of LC3-II/LC3-I significantly increased. In addition, compared with the control group, mitochondrial membrane potential decreased in a dose-dependent manner, and mitochondrial dynamics-related genes SIRT1, SIRT3, and Mfn2 mRNA decreased significantly in the Cr(VI) treatment group. In this study, we concluded that Cr(VI) could cause broiler myocardial apoptosis and autophagy by inducing mitochondrial dysfunction and oxidative stress.

Mitofusin 2 Expression in Placental Tissues of Preeclamptic Patients and Its Correlations with Trophoblast Invasion and Placental Hypoxia

The researcher aimed to detect mitofusin 2 (Mfn2) expression in the placental tissues of preeclampsia (PE) patients and correlations with trophoblast invasion and placental hypoxia. Mfn2 mRNA expressions in placental tissues from PE and healthy pregnant women were detected by qRT-PCR. Trophoblast cells JEG-3 were transfected with small-interfering RNA-Mfn2 (si-Mfn2). Proliferation was tested by CCK-8 and colony formation assays. Invasion and migration were determined with Transwell assay. Mfn2, HIF-1á, HPH-1 and leptin protein expressions were detected by Western blotting. Mfn2 protein had strong positive and weak negative expressions in normal and PE women, respectively. Mfn2 mRNA expression in PE women was lower than that in normal women (P&lt;0.05). Compared with control and si- NC groups, si-Mfn2 group had lower proliferation, migration and invasion abilities, as well as HIF-1á, HPH-1 and leptin expressions (P&lt;0.05). Mfn2 expression in the placental tissues of PE women obviously decreases, which inhibits trophoblast invasion and triggers placental hypoxia.

Study of long non-coding RNA and mitochondrial dysfunction in diabetic rats

Diabetes mellitus (DM) is a worldwide health problem. The Micro- and macro-vascular complications are the major causes of morbidity and mortality of DM. Molecular regulation of mitochondrial fission/fusion cycles is being studied, but the results were not conclusive. The aim of this study is to investigate the possible functional role of lncRNA H19 and its relation to mitofusin-2 (Mfn-2) gene expression in diabetic rats with cardiac and renal complications. Streptozotocin-induced diabetic male, albino rats and a matched control group were investigated. Cardiac weights, blood pressure and ECG were recorded. Biochemical evaluation of cardiac and renal functions was performed. Molecular determination of lncRNA H19 and Mfn-2 gene expression and histological examination by light and electron microscopy for cardiac and renal tissues were performed. Diabetic rats showed a significant increase of left ventricle weight/whole body weight ratio, R wave voltage, and a significant decrease of blood pressure, heart rate, and P wave voltage. At the molecular level, lncRNA H19 and Mfn-2 mRNA showed altered expression with a statistically significant downregulation of Mfn-2 mRNA expression in renal tissues. In conclusion, the changes in lncRNA H19 and Mfn-2 mRNA expression may help better understanding of the pathogenesis of cardiac and renal dysfunctions associated with type 1 DM.

Thymoquinone alleviates mitochondrial viability and apoptosis in diclofenac-induced acute kidney injury (AKI) via regulating Mfn2 and miR-34a mRNA expressions.

The current study was prepared to assess the underlying mechanism of diclofenac (Diclo)-stimulated renal oxidative damage (50 mg/kg/day for two consecutive days I.P) and antioxidative, and antiapoptotic effects of Thymoquinone (20 mg/kg/day for 21 days P.O). Exposure of rats to Diclo significantly increased serum urea and creatinine, decreased GSH, catalase, and total antioxidant capacity with a concomitant increase of lipid peroxidation. Diclo significantly decreased renal mitochondrial viability %, increased DNA fragmentation %, caspase 3 activity, and cytochrome C (Cyt C) concentration. Molecular investigations revealed that Diclo administration caused a significant reduction of mitofusin-2 (Mfn2) and increase of microRNA-34a (miR-34a) mRNA expressions with a concomitant decrease of Nrf2 and HO-1 mRNA expressions/protein levels and increase of NF-κB mRNA expressions. Thymoquinone restored renal oxidative/antioxidant redox. Thymoquinone significantly increased the renal mitochondrial viability % and reduced renal DNA fragmentation %, caspase 3 activity, and Cyt C. Moreover, thymoquinone modulated renal Mfn2 and miR-34a as compared to Diclo group. Our findings were confirmed by immunohistochemical assays for detecting the iNOS and NOX4 in renal tissue as well as histopathological investigations. Obtained results demonstrated that thymoquinone possess a potential antioxidant, antiapoptotic defense and exhibited a strong nephroprotective activity against Diclo-induced toxicity.

Effects on learning and memory and mitochondrial energy metabolism in hippocampus of mice by subacute exposure to n-hexane

Objective: To study the effects on learning and memory, mitochondrial energy metabolism and ATPase activity of hippocampus in mice with subacute exposure to n-hexane. Methods: The SPF 40 Kunming mice were randomly divided into low, middle and high dose groups and control groups according to different dosages. Each group consisted of 10 mice. The mice were given n-hexane by gavage, the mice in the low, middle and high dose groups were given 0.2 ml/d of n-hexane at concentrations of 500, 1000 and 2000 mg/kg respectively, while the mice in the control group were given 0.2 ml/d of cooking oil once a day for 28 days. The y-type maze test, the activity of ATP Enzyme, mitochondrial respiratory chain enzyme complex Ⅰ-IV, the mrna of mitochondrial fusion gene (MFn1, Mfn2) and fission gene (FIs1) in brain tissues were performed. Results: Except for the wrong reaction times of low-dose exposure group in the first test, there existed significantly different in the first and second Y-maze tests in exposure groups and control group (P<0.05) ; in low, middle and high-dose group, the Na(+)-K(+)-ATPase activities were (8.27±2.65) , (5.38±1.55) , (3.55±1.69) μmol/gprot/h, and Ca(2+)-Mg(2+)-ATPase activities were (10.32±2.96) , (7.19±1.94) and (4.49±1.33) μmol/gprot/h, respectively. Compared with those in control group, the activities of Na(+)-K(+)-ATPase and Ca(2+)-Mg(2+)-ATPase decreased significantly in middle-dose group and high-dose group (P<0.05) . Compared with those in control group, the activities of mitochondrial respiratory chain enzyme complex I-IV in each dose group were significantly decreased (P<0.05) . The expressions of Mfn1mRNA and Mfn2mRNA in each dose group was significantly lower than those in control group (P<0.05) . Conclusion: Subacute exposure to n-hexane can result in the decrease of activities of mitochondrial respiratory chain enzyme complex in hippocampus of mice, which may lead to the disorder of mitochondrial energy metabolism by the decrease of ATPase activity and the imbalance of mitochondrial fusion-division, which must be one of the mechanisms of impairment of learning and memory of mice induced by n-hexane.

Graded reductions in pre‐exercise glycogen concentration do not augment exercise‐induced nuclear AMPK and PGC‐1α protein content in human muscle

What is the central question of this study? What is the absolute level of pre-exercise glycogen concentration required to augment the exercise-induced signalling response regulating mitochondrial biogenesis? What is the main finding and its importance? Commencing high-intensity endurance exercise with reduced pre-exercise muscle glycogen concentrations confers no additional benefit to the early signalling responses that regulate mitochondrial biogenesis. We examined the effects of graded muscle glycogen on the subcellular location and protein content of AMP-activated protein kinase (AMPK) and peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) and mRNA expression of genes associated with the regulation of mitochondrial biogenesis and substrate utilisation in human skeletal muscle. In a repeated measures design, eight trained male cyclists completed acute high-intensity interval (HIT) cycling (8×5min at 80% peak power output) with graded concentrations of pre-exercise muscle glycogen. Following initial glycogen-depleting exercise, subjects ingested 2gkg-1 (L-CHO), 6gkg-1 (M-CHO) or 14gkg-1 (H-CHO)of carbohydrateduring a 36hperiod, such that exercise was commenced with graded (P<0.05) muscle glycogen concentrations (mmol(kgdw)-1 : H-CHO, 531±83; M-CHO, 332±88; L-CHO, 208±79). Exercise depleted muscle glycogen to <300mmol(kgdw)-1 in all trials (mmol(kgdw)-1 : H-CHO, 270±88; M-CHO, 173±74; L-CHO, 100±42) and induced comparable increases in nuclear AMPK protein content (∼2-fold)and PGC-1α (∼5-fold), p53 (∼1.5-fold) and carnitine palmitoyltransferase 1 (∼2-fold) mRNA between trials (all P<0.05). The magnitude of increase in PGC-1α mRNA was also positively correlated with post-exercise glycogen concentration (P<0.05). In contrast, neither exercise nor carbohydrate availability affected the subcellular location of PGC-1α protein or PPAR, SCO2, SIRT1, DRP1, MFN2 or CD36 mRNA. Using a sleep-low, train-low model with a high-intensity endurance exercise stimulus, we conclude that pre-exercise muscle glycogen does not modulate skeletal muscle cell signalling.

Involvement of Mfn2, Bcl2/Bax signaling and mitochondrial viability in the potential protective effect of Royal jelly against mitochondria-mediated ovarian apoptosis by cisplatin in rats.

Objective(s):The current study aimed to assess cisplatin-mediated ovarian apoptosis in a rat model by Royal jelly (RJ). Materials and Methods:Thirty female adult albino rats (180-200 g) were divided into three groups (n=10): saline (0.9% NaCl, IP) was given to the control group, the cisplatin group: received (5 mg/kg/once a week IP) for 5 successive weeks, the RJ+Cis. group: received RJ (100 mg/kg/ day PO daily), and Cisplatin (5 mg/kg/once per week IP) for 5 successive weeks. At the end of the experiment, rats were sacrificed and their ovaries were isolated and used for biochemical analysis, molecular investigations and morphometric assessment as well as histological study. Moreover, blood samples were collected for determination of follicle-stimulating hormone (FSH), luteinizing hormone (LH), Estradiol, progesterone and anti-mullerian hormone (AMH).Results:The current study clarified that RJ given to rats prior to cisplatin significantly increased the ovarian and uterine weights, in addition to follicular count at P˂0.05 compared to rats injected only with cisplatin. Moreover, it restored normal ovarian histological structure with a concurrent reduction in FSH, and LH levels, and increased AMH and ovarian hormone concentrations at P˂0.05 compared to cisplatin group. Also, RJ decreased the ovarian antioxidant/oxidative imbalance harmonized with significant suppression of inducible nitric oxide synthase and increase of quinone oxidoreductase 1 mRNA expression at P˂0.05 compared to cisplatin group.Conclusion:We concluded that RJ could alleviate mitochondrial-induced ovarian apoptosis caused by cisplatin via increasing anti-apoptotic Bcl2, and diminishing pro-apoptotic Bax with a concomitant increase of Mfn2 mRNA and protein expressions.

92: A novel epigenetic mechanism underlying maternal diabetes-suppressed mitochondrial fusion in congenital heart disease

Maternal diabetes, induces congenital heart defects (CHDs), the most common structural birth defects in human. microRNAs (miRNA) are non-coding RNAs, which represses gene expression by degrading mRNA and/or inhibiting translation. Previous studies indicate that miRNAs are potentially involved in the pathogenesis of heart defects in diabetic pregnancy. The present study investigates the role of miR-140 in maternal diabetics-induced CHDs by examining its impact on mitochondrial dynamics. Type 1 diabetes in mir140 heterozygous (miR-140+/-) female mice was induced by streptozotocin (STZ) injections. Nondiabetic miR-140+/- males mated with nondiabetic and diabetic miR-140+/-to generate hearts from embryonic day 12.5 (E12.5) and E17.5 embryos for biochemical assessment and morphological examination of CHDs, respectively. Cardiomyocytes isolated from E12.5 hearts were treated with normal (5 mM glucose) and high glucose (25 mM glucose). miR-140 expression was significantly upregulated by maternal diabetes in vivo and high glucose in vitro. miR-140 homozygous deletion significantly reduced the CHD rate from 29.1% in Wild-type (WT) embryos to 4.4% in diabetic pregnancy. miR-140 heterozygous deletion slightly reduced the CHD incidence. Maternal diabetes suppressed mitofusin 1 (Mfn1) gene expression leading to impaired mitochondrial fusion. miR-140 targeted the Mfn1 mRNA resulting in its degradation. miR-140 homozygous deletion rescued Mfn1 expression in cardiomyocytes of E12.5 hearts exposed to maternal diabetes. Mitochondrial marker Tom20 immunofluorescence staining and mitochondrial time-lapse high resolution confocal microscopy revealed that maternal diabetes induced mitochondrial fragmentation due to mitochondrial fusion impairment in embryonic cardiomyocytes. Our study demonstrates that miR-140 is critically involved in the pathogenesis of maternal diabetes-induced CHDs. miR-140 suppresses Mfn1 expression leading to impaired mitochondrial fusion. The miR-140-Mfn1-impaired mitochondrial fusion axis mediates the teratogenic effect of maternal diabetes.

RNA binding protein HuD contributes to β-cell dysfunction by impairing mitochondria dynamics.

Imbalanced mitochondrial dynamics in pancreatic β-cells contributes to β-cell dysfunction in diabetes; however, the molecular mechanisms underlying mitochondrial dynamics in the pathology of diabetes are not fully elucidated. We previously reported the reduction of RNA binding protein HuD in pancreatic β-cells of diabetes. Herein, we demonstrate that HuD plays a novel role in the regulation of mitochondrial dynamics by promoting mitochondrial fusion. We show enhanced mitochondrial fragmentation in the pancreas of db/db mice and HuD KO mice. Downregulation of HuD increases the number of cells with fragmented mitochondria and reduces the mitochondrial activity determined by mitochondrial membrane potential and ATP production in mouse insulinoma βTC6 cells. HuD binds to 3'-untraslated region of mitofusin 2 (Mfn2) mRNA and positively regulates its expression. Ectopic expression of Mfn2 in βTC6 cells stably expressing short hairpin RNA against HuD (shHuD) restores HuD-mediated mitochondrial dysfunction. Taken together, our results suggest that HuD regulates mitochondrial dynamics by regulating Mfn2 level and its reduced expression leads to mitochondrial dysfunction in pancreatic β-cells.