Effect of uridine on mitochondrial function / 生物工程学报

Uridine is one of the essential nutrients in organisms. To maintain normal cell growth and intracellular metabolism, the uridine must be maintained at certain concentration. Recent studies have shown that uridine can reduce inflammatory response in organisms, participate in glycolysis, and regulate intracellular protein modification, such as glycosylation and acetylation. Furthermore, it can protect cells from hypoxic injury by reducing intracellular oxidative stress, promoting high-energy compounds synthesis. Previous studies have shown that the protective effects of uridine are closely related to its effect on mitochondria. This review summarizes the effect of uridine on mitochondrial function.

Overexpression of miR-431-5p impairs mitochondrial function and induces apoptosis in gastric cancer cells via the Bax/Bcl-2/caspase3 pathway / 南方医科大学学报

OBJECTIVE@#To investigate the expression of microRNA miR-431-5p in gastric cancer (GC) tissues and its effects on apoptosis and mitochondrial function in GC cells.@*METHODS@#The expression level of miR-431-5p in 50 clinical samples of GC tissues and paired adjacent tissues was detected using real-time fluorescence quantitative PCR, and its correlation with the clinicopathological features of the patients was analyzed. A cultured human GC cell line (MKN-45 cells) were transfected with a miR-431-5p mimic or a negative control sequence, and the cell proliferation, apoptosis, mitochondrial number, mitochondrial potential, mitochondrial permeability transition pore (mPTP), reactive oxygen species (ROS) production and adenosine triphosphate (ATP) content were detected using CCK-8 assay, flow cytometry, fluorescent probe label, or ATP detection kit. The changes in the expression levels of the apoptotic proteins in the cells were detected with Western blotting.@*RESULTS@#The expression level of miR-431-5p was significantly lower in GC tissues than in the adjacent tissues (P < 0.001) and was significantly correlated with tumor differentiation (P=0.0227), T stage (P=0.0184), N stage (P=0.0005), TNM stage (P=0.0414) and vascular invasion (P=0.0107). In MKN-45 cells, overexpression of miR-431-5p obviously inhibited cell proliferation and induced cell apoptosis, causing also mitochondrial function impairment as shown by reduced mitochondrial number, lowered mitochondrial potential, increased mPTP opening, increased ROS production and reduced ATP content. Overexpression of miR-431-5p significantly downregulated the expression of Bcl-2 and increased the expressions of pro-apoptotic proteins p53, Bcl-2 and cleaved caspase-3 protein.@*CONCLUSION@#The expression of miR-431-5p is down-regulated in GC, which results in mitochondrial function impairment and promotes cell apoptosis by activating the Bax/Bcl-2/caspase3 signaling pathway, suggesting the potential role of miR-431-5p in targeted therapy for GC.

Lyciumbarbarum polysaccharides ameliorate canine acute liver injury by reducing oxidative stress, protecting mitochondrial function, and regulating metabolic pathways / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

The development of acute liver injury can result in liver cirrhosis, liver failure, and even liver cancer, yet there is currently no effective therapy for it. The purpose of this study was to investigate the protective effect and therapeutic mechanism of Lyciumbarbarum polysaccharides (LBPs) on acute liver injury induced by carbon tetrachloride (CCl4). To create a model of acute liver injury, experimental canines received an intraperitoneal injection of 1 mL/kg of CCl4 solution. The experimental canines in the therapy group were then fed LBPs (20 mg/kg). CCl4-induced liver structural damage, excessive fibrosis, and reduced mitochondrial density were all improved by LBPs, according to microstructure data. By suppressing Kelch-like epichlorohydrin (ECH)-associated protein 1 (Keap1), promoting the production of sequestosome 1 (SQSTM1)/p62, nuclear factor erythroid 2-related factor 2 (Nrf2), and phase II detoxification genes and proteins downstream of Nrf2, and restoring the activity of anti-oxidant enzymes like catalase (CAT), LBPs can restore and increase the antioxidant capacity of liver. To lessen mitochondrial damage, LBPs can also enhance mitochondrial respiration, raise tissue adenosine triphosphate (ATP) levels, and reactivate the respiratory chain complexes I‒V. According to serum metabolomics, the therapeutic impact of LBPs on acute liver damage is accomplished mostly by controlling the pathways to lipid metabolism. 9-Hydroxyoctadecadienoic acid (9-HODE), lysophosphatidylcholine (LysoPC/LPC), and phosphatidylethanolamine (PE) may be potential indicators of acute liver injury. This study confirmed that LBPs, an effective hepatoprotective drug, may cure acute liver injury by lowering oxidative stress, repairing mitochondrial damage, and regulating metabolic pathways.

Effect of Guizhi Fuling Capsule on Apoptosis of Myeloma Cells Through Mitochondrial Apoptosis Pathway / 中国结合医学杂志

OBJECTIVE@#To observe the effects of Guizhi Fuling Capsule (GZFLC) on myeloma cells and explore the mechanisms.@*METHODS@#MM1S and RPMI 8226 cells were co-cultured with different concentrations of serum and the cell experiments were divided into negative (10%, 20% and 40%) groups, GZFLC (10%, 20%, and 40%) groups and a control group. Cell counting kit-8 (CCK-8) assays and flow cytometry were used to detect the viability and apoptosis levels of myeloma cells. The effects on mitochondria were examined by reactive oxygen specie (ROS) and tetrechloro-tetraethylbenzimidazol carbocyanine iodide (JC-1) assays. Western blot was used to detect the expression of B cell lymphoma-2 (Bcl-2), Bcl-2-associated X (Bax), cleaved caspase-3, -9, cytochrome C (Cytc) and apoptotic protease-activating factor 1 (Apaf-1). RPMI 8226 cells (2 × 107) were subcutaneously inoculated into 48 nude mice to study the in vivo antitumor effects of GZFLC. The mice were randomly divided into four groups using a completely randomized design, the high-, medium-, or low-dose GZFLC (840, 420, or 210 mg/kg per day, respectively) or an equal volume of distilled water, administered daily for 15 days. The tumor volume changes in and survival times of the mice in the GZFLC-administered groups and a control group were observed. Cytc and Apaf-1 expression levels were detected by immunohistochemistry.@*RESULTS@#GZFLC drug serum decreased the viability and increased the apoptosis of myeloam cells (P<0.05). In addition, this drug increased the ROS levels and decreased the mitochondrial membrane potential (P<0.01). Western blot showed that the Bcl-2/Bax ratios were decreased in the GZFLC drug serum-treated groups, whereas the expression levels of cleaved caspase-3, -9, Cytc and Apaf-1 were increased (all P<0.01). Over time, the myeloma tumor volumes of the mice in the GZFLC-administered groups decreased, and survival time of the mice in the GZFLC-administered groups were longer than that of the mice in the control group. Immunohistochemical analysis of tumor tissues from the mice in the GZFLC-administered groups revealed that the Cytc and Apaf-1 expression levels were increased (P<0.05).@*CONCLUSION@#GZFLC promoted apoptosis of myeloma cells through the mitochondrial apoptosis pathway and significantly reduced the tumor volumes in mice with myeloma, which prolonged the survival times of the mice.

Role of Mitophagy in Myocardial Ischemia/Reperfusion Injury and Chinese Medicine Treatment / 中国结合医学杂志

Mitophagy is one of the important targets for the prevention and treatment of myocardial ischemia/reperfusion injury (MIRI). Moderate mitophagy can remove damaged mitochondria, inhibit excessive reactive oxygen species accumulation, and protect mitochondria from damage. However, excessive enhancement of mitophagy greatly reduces adenosine triphosphate production and energy supply for cell survival, and aggravates cell death. How dysfunctional mitochondria are selectively recognized and engulfed is related to the interaction of adaptors on the mitochondrial membrane, which mainly include phosphatase and tensin homolog deleted on chromosome ten (PTEN)-induced kinase 1/Parkin, hypoxia-inducible factor-1 α/Bcl-2 and adenovirus e1b19k Da interacting protein 3, FUN-14 domain containing protein 1 receptor-mediated mitophagy pathway and so on. In this review, the authors briefly summarize the main pathways currently studied on mitophagy and the relationship between mitophagy and MIRI, and incorporate and analyze research data on prevention and treatment of MIRI with Chinese medicine, thereby provide relevant theoretical basis and treatment ideas for clinical prevention of MIRI.

4E-BP1 counteracts human mesenchymal stem cell senescence via maintaining mitochondrial homeostasis

Although the mTOR-4E-BP1 signaling pathway is implicated in aging and aging-related disorders, the role of 4E-BP1 in regulating human stem cell homeostasis remains largely unknown. Here, we report that the expression of 4E-BP1 decreases along with the senescence of human mesenchymal stem cells (hMSCs). Genetic inactivation of 4E-BP1 in hMSCs compromises mitochondrial respiration, increases mitochondrial reactive oxygen species (ROS) production, and accelerates cellular senescence. Mechanistically, the absence of 4E-BP1 destabilizes proteins in mitochondrial respiration complexes, especially several key subunits of complex III including UQCRC2. Ectopic expression of 4E-BP1 attenuates mitochondrial abnormalities and alleviates cellular senescence in 4E-BP1-deficient hMSCs as well as in physiologically aged hMSCs. These f indings together demonstrate that 4E-BP1 functions as a geroprotector to mitigate human stem cell senescence and maintain mitochondrial homeostasis, particularly for the mitochondrial respiration complex III, thus providing a new potential target to counteract human stem cell senescence.

Andrographolide protects against atrial fibrillation by alleviating oxidative stress injury and promoting impaired mitochondrial bioenergetics / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Atrial fibrillation (AF) is the most prevalent cardiac arrhythmia seen in clinical settings, which has been associated with substantial rates of mortality and morbidity. However, clinically available drugs have limited efficacy and adverse effects. We aimed to investigate the mechanisms of action of andrographolide (Andr) with respect to AF. We used network pharmacology approaches to investigate the possible therapeutic effect of Andr. To define the role of Andr in AF, HL-1 cells were pro-treated with Andr for 1 h before rapid electronic stimulation (RES) and rabbits were pro-treated for 1 d before rapid atrial pacing (RAP). Apoptosis, myofibril degradation, oxidative stress, and inflammation were determined. RNA sequencing (RNA-seq) was performed to investigate the relevant mechanism. Andr treatment attenuated RAP-induced atrial electrophysiological changes, inflammation, oxidative damage, and apoptosis both in vivo and in vitro. RNA-seq indicated that oxidative phosphorylation played an important role. Transmission electron microscopy and adenosine triphosphate (ATP) content assay respectively validated the morphological and functional changes in mitochondria. The translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) to the nucleus and the molecular docking suggested that Andr might exert a therapeutic effect by influencing the Keap1-Nrf2 complex. In conclusions, this study revealed that Andr is a potential preventive therapeutic drug toward AF via activating the translocation of Nrf2 to the nucleus and the upregulation of heme oxygenase-1 (HO-1) to promote mitochondrial bioenergetics.

Research progress on the role of chondrocyte mitochondrial homeostasis imbalance in the pathogenesis of osteoarthritis / 中国修复重建外科杂志

OBJECTIVE@#To summarize the role of chondrocyte mitochondrial homeostasis imbalance in the pathogenesis of osteoarthritis (OA) and analyze its application prospects.@*METHODS@#The recent literature at home and abroad was reviewed to summarize the mechanism of mitochondrial homeostasis imbalance, the relationship between mitochondrial homeostasis imbalance and the pathogenesis of OA, and the application prospect in the treatment of OA.@*RESULTS@#Recent studies have shown that mitochondrial homeostasis imbalance, which is caused by abnormal mitochondrial biogenesis, the imbalance of mitochondrial redox, the imbalance of mitochondrial dynamics, and damaged mitochondrial autophagy of chondrocytes, plays an important role in the pathogenesis of OA. Abnormal mitochondrial biogenesis can accelerate the catabolic reaction of OA chondrocytes and aggravate cartilage damage. The imbalance of mitochondrial redox can lead to the accumulation of reactive oxygen species (ROS), inhibit the synthesis of extracellular matrix, induce ferroptosis and eventually leads to cartilage degradation. The imbalance of mitochondrial dynamics can lead to mitochondrial DNA mutation, decreased adenosine triphosphate production, ROS accumulation, and accelerated apoptosis of chondrocytes. When mitochondrial autophagy is damaged, dysfunctional mitochondria cannot be cleared in time, leading to ROS accumulation, which leads to chondrocyte apoptosis. It has been found that substances such as puerarin, safflower yellow, and astaxanthin can inhibit the development of OA by regulating mitochondrial homeostasis, which proves the potential to be used in the treatment of OA.@*CONCLUSION@#The mitochondrial homeostasis imbalance in chondrocytes is one of the most important pathogeneses of OA, and further exploration of the mechanisms of mitochondrial homeostasis imbalance is of great significance for the prevention and treatment of OA.

A pair of transporters controls mitochondrial Zn2+ levels to maintain mitochondrial homeostasis

Zn2+ is required for the activity of many mitochondrial proteins, which regulate mitochondrial dynamics, apoptosis and mitophagy. However, it is not understood how the proper mitochondrial Zn2+ level is achieved to maintain mitochondrial homeostasis. Using Caenorhabditis elegans, we reveal here that a pair of mitochondrion-localized transporters controls the mitochondrial level of Zn2+. We demonstrate that SLC-30A9/ZnT9 is a mitochondrial Zn2+ exporter. Loss of SLC-30A9 leads to mitochondrial Zn2+ accumulation, which damages mitochondria, impairs animal development and shortens the life span. We further identify SLC-25A25/SCaMC-2 as an important regulator of mitochondrial Zn2+ import. Loss of SLC-25A25 suppresses the abnormal mitochondrial Zn2+ accumulation and defective mitochondrial structure and functions caused by loss of SLC-30A9. Moreover, we reveal that the endoplasmic reticulum contains the Zn2+ pool from which mitochondrial Zn2+ is imported. These findings establish the molecular basis for controlling the correct mitochondrial Zn2+ levels for normal mitochondrial structure and functions.

Effects of vibration on the expression of mitochondrial fusion and fission genes and ultrastructure of skeletal muscle in rabbits / 中华劳动卫生职业病杂志

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.

Interleukin-13 promotes cellular senescence through inducing mitochondrial dysfunction in IgG4-related sialadenitis / 国际口腔科学杂志·英文版

Immunoglobulin G4-related sialadenitis (IgG4-RS) is an immune-mediated fibro-inflammatory disease and the pathogenesis is still not fully understood. The aim of this study was to explore the role and mechanism of interleukin-13 (IL-13) in the cellular senescence during the progress of IgG4-RS. We found that the expression of IL-13 and IL-13 receptor α1 (IL-13Rα1) as well as the number of senescent cells were significantly higher in the submandibular glands (SMGs) of IgG4-RS patients. IL-13 directly induced senescence as shown by the elevated activity of senescence-associated β-galactosidase (SA-β-gal), the decreased cell proliferation, and the upregulation of senescence markers (p53 and p16) and senescence-associated secretory phenotype (SASP) factors (IL-1β and IL-6) in SMG-C6 cells. Mechanistically, IL-13 increased the level of phosphorylated signal transducer and activator of transcription 6 (p-STAT6) and mitochondrial-reactive oxygen species (mtROS), while decreased the mitochondrial membrane potential, ATP level, and the expression and activity of superoxide dismutase 2 (SOD2). Notably, the IL-13-induced cellular senescence and mitochondrial dysfunction could be inhibited by pretreatment with either STAT6 inhibitor AS1517499 or mitochondria-targeted ROS scavenger MitoTEMPO. Moreover, IL-13 increased the interaction between p-STAT6 and cAMP-response element binding protein (CREB)-binding protein (CBP) and decreased the transcriptional activity of CREB on SOD2. Taken together, our findings revealed a critical role of IL-13 in the induction of salivary gland epithelial cell senescence through the elevated mitochondrial oxidative stress in a STAT6-CREB-SOD2-dependent pathway in IgG4-RS.

Integrated metabolism and epigenetic modifications in the macrophages of mice in responses to cold stress / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

The negative effects of low temperature can readily induce a variety of diseases. We sought to understand the reasons why cold stress induces disease by studying the mechanisms of fine-tuning in macrophages following cold exposure. We found that cold stress triggers increased macrophage activation accompanied by metabolic reprogramming of aerobic glycolysis. The discovery, by genome-wide RNA sequencing, of defective mitochondria in mice macrophages following cold exposure indicated that mitochondrial defects may contribute to this process. In addition, changes in metabolism drive the differentiation of macrophages by affecting histone modifications. Finally, we showed that histone acetylation and lactylation are modulators of macrophage differentiation following cold exposure. Collectively, metabolism-related epigenetic modifications are essential for the differentiation of macrophages in cold-stressed mice, and the regulation of metabolism may be crucial for alleviating the harm induced by cold stress.

MicroRNA-132 promotes atherosclerosis by inducing mitochondrial oxidative stressmediated ferroptosis / 南方医科大学学报

OBJECTIVE@#To explore the expression of microRNA-132 (miR-132) and its potential role in the development of atherosclerosis (AS).@*METHODS@#Thirty AS samples and 30 samples of normal peripheral vessels were collected from atherosclerotic patients undergoing peripheral angiostomy in our hospital for detecting the expression level of miR-132 using RT-qPCR. The expression of miR-132 in human umbilical vein endothelial cells (HUVEC) was up-regulated by liposome transfection, and intracellular reactive oxygen species (ROS), localization relationship between ROS and mitochondria, functional changes of mitochondrial reactive oxygen superoxide species (mtROS), mitochondrial membrane potential (MMP) and opening of mitochondrial permeability transition pore (mPTP) were analyzed by flow cytometry and laser confocal microscopy. The activity of mitochondrial redox respiratory chain complex (type I, II, III, IV and V) in HUVECs was detected using ELISA, and the expression levels of key iron death proteins were detected with Western blotting.@*RESULTS@#RT-qPCR results showed that miR-132 was significantly up-regulated in atherosclerotic plaques compared with normal vascular samples (P < 0.001). Compared with control HUVECs, HUVECs overexpressing miR-132 showed a significantly increased level of intracellular ROS (P < 0.001), and most of ROS was colocalized with mitochondria. HUVECs overexpressing miR-132 also showed significantly decreased MMP (P < 0.001) and obviously increased mtROS (P < 0.001) and opening of mPTP (P < 0.001), which led to mitochondrial REDOX respiratory chain stress disorder. The key iron death protein GPX4 was significantly down-regulated and the oxidized protein NOX4 was significantly increased in miR-132-overexpressing HUVECs (P < 0.001).@*CONCLUSION@#MiR-132 promotes atherosclerosis by inducing mitochondrial oxidative stress-mediated ferroptosis, which may serve as a promising therapeutic target for AS.

Mechanisms of Acupuncture in Improving Alzheimer's Disease Caused by Mitochondrial Damage / 中国结合医学杂志

Alzheimer's disease (AD) is one of the most common neurodegenerative diseases among the elderly and it accounts for nearly 80% of all dementias. The pathogenesis of AD is complicated and enigmatic thus far. The mitochondrial cascade hypothesis assumes that mitochondrial damage may mediate, drive, or contribute to a variety of AD pathologies and may be the main factor in late-onset AD. Currently, there are no widely recognized drugs able to attenuate mitochondrial damage in AD. Notably, increasing evidence supports the efficacy of acupuncture for improving the mitochondrial structure and protecting mitochondrial functions in AD. This review reports the mechanisms by which acupuncture regulates mitochondrial dynamics, energy metabolism, calcium homeostasis and apoptosis. In conclusion, these findings suggest that AD mitochondrial dysfunction represents a reasonable therapeutic target and acupuncture could play a significant role in preventing and treating AD.

Hepatocyte growth factor protects pulmonary endothelial barrier against oxidative stress and mitochondria-dependent apoptosis / 中华医学杂志(英文版)

BACKGROUND@#Pulmonary microvascular endothelial cells (PMVECs) were not complex, and the endothelial barrier was destroyed in the pathogenesis progress of acute lung injury (ALI)/acute respiratory distress syndrome (ARDS). Previous studies have demonstrated that hepatocyte growth factor (HGF), which was secreted by bone marrow mesenchymal stem cells, could decrease endothelial apoptosis. We investigated whether mTOR/STAT3 signaling acted in HGF protective effects against oxidative stress and mitochondria-dependent apoptosis in lipopolysaccharide (LPS)-induced endothelial barrier dysfunction and ALI mice.@*METHODS@#In our current study, we introduced LPS-induced PMEVCs with HGF treatment. To investigate the effects of mammalian target of rapamycin (mTOR)/signal transducer and activator of transcription 3 (STAT3) pathway in endothelial oxidative stress and mitochondria-dependent apoptosis, mTOR inhibitor rapamycin and STAT3 inhibitor S3I-201 were, respectively, used to inhibit mTOR/STAT3 signaling. Moreover, lentivirus vector-mediated mTORC1 (Raptor) and mTORC2 (Rictor) gene knockdown modifications were introduced to evaluate mTORC1 and mTORC1 pathways. Calcium measurement, reactive oxygen species (ROS) production, mitochondrial membrane potential and protein, cell proliferation, apoptosis, and endothelial junction protein were detected to evaluate HGF effects. Moreover, we used the ALI mouse model to observe the mitochondria pathological changes with an electron microscope in vivo.@*RESULTS@#Our study demonstrated that HGF protected the endothelium via the suppression of ROS production and intracellular calcium uptake, which lead to increased mitochondrial membrane potential (JC-1 and mitochondria tracker green detection) and specific proteins (complex I), raised anti-apoptosis Messenger Ribonucleic Acid level (B-cell lymphoma 2 and Bcl-xL), and increased endothelial junction proteins (VE-cadherin and occludin). Reversely, mTOR inhibitor rapamycin and STAT3 inhibitor S3I-201 could raise oxidative stress and mitochondria-dependent apoptosis even with HGF treatment in LPS-induced endothelial cells. Similarly, mTORC1 as well as mTORC2 have the same protective effects in mitochondria damage and apoptosis. In in vivo experiments of ALI mouse, HGF also increased mitochondria structural integrity via the mTOR/STAT3 pathway.@*CONCLUSION@#In all, these reveal that mTOR/STAT3 signaling mediates the HGF suppression effects to oxidative level, mitochondria-dependent apoptosis, and endothelial junction protein in ARDS, contributing to the pulmonary endothelial survival and barrier integrity.

Effects of sulforaphane on brain mitochondria: mechanistic view and future directions / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

The organosulfur compound sulforaphane (SFN; C6H11NOS2) is a potent cytoprotective agent promoting antioxidant, anti-inflammatory, antiglycative, and antimicrobial effects in in vitro and in vivo experimental models. Mitochondria are the major site of adenosine triphosphate (ATP) production due to the work of the oxidative phosphorylation (OXPHOS) system. They are also the main site of reactive oxygen species (ROS) production in nucleated human cells. Mitochondrial impairment is central in several human diseases, including neurodegeneration and metabolic disorders. In this paper, we describe and discuss the effects and mechanisms of action by which SFN modulates mitochondrial function and dynamics in mammalian cells. Mitochondria-related pro-apoptotic effects promoted by SFN in tumor cells are also discussed. SFN may be considered a cytoprotective agent, at least in part, because of the effects this organosulfur agent induces in mitochondria. Nonetheless, there are certain points that should be addressed in further experiments, indicated here as future directions, which may help researchers in this field of research.

Structural characteristics and catalytic cycle of dihydroorotate dehydrogenase-a review / 生物工程学报

Dihydroorotate dehydrogenase is a flavin-dependent mitochondrial enzyme to catalyze the fourth step of the de novo synthesis of pyrimidine and to oxidize dihydroorotate to orotate. By selectively inhibiting dihydroorotate dehydrogenase, thereby inhibiting pyrimidine synthesis, the enzyme has been developed for the treatment of cancer, autoimmune diseases, bacterial or viral infections, parasitic diseases and so on. The development of inhibitory drugs requires a detailed understanding of the structural characteristics and catalytic cycle mechanism of dihydroorotate dehydrogenase. Therefore, this paper reviews these two aspects, and indicates perspectives of these inhibitors in clinical application.

CRISPR/Cas9-mediated MSTN gene editing induced mitochondrial alterations in C2C12 myoblast cells

Background: Myostatin (MSTN) negatively regulates muscle mass and is a potent regulator of energy metabolism. However, MSTN knockout have affect mitochondrial function. This research assessed the mitochondrial energy metabolism of Mstn−/+ KO cells, and wondered whether the mitochondria biogenesis are affected. Results: In this study, we successfully achieved Mstn knockout in skeletal muscle C2C12 cells using a CRISPR/Cas9 system and measured proliferation and differentiation using the Cell-Counting Kit-8 assay and qPCR, respectively. We found that MSTN dysfunction could promote proliferation and differentiation compared with the behaviour of wild-type cells. Moreover, Mstn KO induced an increase in KIF5B expression. The mitochondrial content was significantly increased in Mstn KO C2C12 cells, apparently associated with the increases in PGC-1α, Cox1, Cox2, ND1 and ND2 expression. However, no differences were observed in glucose consumption and lactate production. Interestingly, Mstn KO C2C12 cells showed an increase in IL6 and a decrease in TNF-1α levels. Conclusion: These findings indicate that MSTN regulates mitochondrial biogenesis and metabolism. This gene-editing cells provided favourable evidence for animal breeding and metabolic diseases.

Mitochondrial superoxide anions induced by exogenous oxidative stress determine tumor cell fate: an individual cell-based study / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

OBJECTIVE@#Reactive oxygen species (ROS) are involved in a variety of biological phenomena and serve both deleterious and beneficial roles. ROS quantification and assessment of reaction networks are desirable but difficult because of their short half-life and high reactivity. Here, we describe a pro-oxidative model in a single human lung carcinoma SPC-A-1 cell that was created by application of extracellular H2O2 stimuli.@*METHODS@#Modified microfluidics and imaging techniques were used to determine O2 •- levels and construct an O2 •- reaction network. To elucidate the consequences of increased O2 •- input, the mitochondria were given a central role in the oxidative stress mode, by manipulating mitochondria-interrelated cytosolic Ca2+ levels, mitochondrial Ca2+ uptake, auto-amplification of intracellular ROS and the intrinsic apoptotic pathway.@*RESULTS AND CONCLUSIONS@#Results from a modified microchip demonstrated that 1 mmol/L H2O2 induced a rapid increase in cellular O2 •- levels (>27 vs. >406 amol in 20 min), leading to increased cellular oxidizing power (evaluated by ROS levels) and decreased reducing power (evaluated by glutathione (GSH) levels). In addition, we examined the dynamics of cytosolic Ca2+ and mitochondrial Ca2+ by confocal laser scanning microscopy and confirmed that Ca2+ stores in the endoplasmic reticulum were the primary source of H2O2-induced cytosolic Ca2+ bursts. It is clear that mitochondria have pivotal roles in determining how exogenous oxidative stress affects cell fate. The stress response involves the transfer of Ca2+ signals between organelles, ROS auto-amplification, mitochondrial dysfunction, and a caspase-dependent apoptotic pathway.

Combatiendo el metabolismo de las células cancerosas mediante la activación de SIRT3 y el ejercicio físico / Combating tumor cells through SIRT3 activation and exercise

One of the main features of cancer is the high rate of cell proliferation and growth. To do this, cancer cells need to redirect their metabolism mainly towards anaerobic glycolysis and an increased mitochondrial glutamine energy metabolism. Sirtuins are cellular proteins with regulatory functions on metabolic pathways, genomic stability, apoptosis, longevity, inflammation, energy metabolism and oxidative stress. Sirtuins have emerged recently as a potential therapeutic option to treat several chronic diseases including cancer. This review summarizes the tumor suppressor function of Sirtuin 3 (SIRT3), highlighting its repressor effect on glycolytic metabolism, promoting mitochondrial metabolism and oxidative stress reduction. SIRT3 activation by exercise is particularly described since it may represent a potent tool for several types of cancer treatment.