Effect of Endometriosis on Cumulus ATP, Number of Mitochondria and Oocyte Maturity in Cumulus Oocyte Complex in Mice / Efeito da endometriose no cumulus ATP, número de mitocôndrias e maturidade oocitária no complexo oocitário cumulus em camundongos

Abstract Objective Endometriosis causes a decrease in oocyte quality. However, this mechanism is not fully understood. The present study aimed to analyze the effect of endometriosis on cumulus cell adenosine triphosphate ATP level, the number of mitochondria, and the oocyte maturity level. Methods A true experimental study with a post-test only control group design on experimental animals. Thirty-two mice were divided into control and endometriosis groups. Cumulus oocyte complex (COC) was obtained from all groups. Adenosine triphosphate level on cumulus cells was examined using the Elisa technique, the number of mitochondria was evaluated with a confocal laser scanning microscope and the oocyte maturity level was evaluated with an inverted microscope. Results The ATP level of cumulus cells and the number of mitochondria in the endometriosis group increased significantly (p < 0.05; p < 0.05) while the oocyte maturity level was significantly lower (p < 0.05). There was a significant relationship between ATP level of cumulus cells and the number of mitochondrial oocyte (p < 0.01). There was no significant relationship between cumulus cell ATP level and the number of mitochondrial oocytes with oocyte maturity level (p > 0.01; p > 0.01). The ROC curve showed that the number of mitochondrial oocytes (AUC = 0.672) tended to be more accurate than cumulus cell ATP level (AUC = 0.656) in determining the oocyte maturity level. Conclusion In endometriosis model mice, the ATP level of cumulus cells and the number of mitochondrial oocytes increased while the oocyte maturity level decreased. There was a correlation between the increase in ATP level of cumulus cells and an increase in the number of mitochondrial oocytes.

Correlation of mitochondrial tRNA variants with coronary heart disease in a Chinese pedigree / 中华医学遗传学杂志

OBJECTIVE@#To explore the correlation of mitochondrial DNA (mtDNA) variants and coronary heart disease (CHD) in a Chinese pedigree and the possible molecular mechanisms.@*METHODS@#A Chinese pedigree featuring matrilineal inheritance of CHD who visited Hangzhou First People's Hospital in May 2022 was selected as the study subject. Clinical data of the proband and her affected relatives was collected. By sequencing the mtDNA of the proband and her pedigree members, candidate variants were identified through comparison with wild type mitochondrial genes. Conservative analysis among various species was conducted, and bioinformatics software was used to predict the impact of variants on the secondary structure of tRNA. Real-time PCR was carried out to determine the copy number of mtDNA, and a transmitochondrial cell line was established for analyzing the mitochondrial functions, including membrane potential and ATP level.@*RESULTS@#This pedigree had contained thirty-two members from four generations. Among ten maternal members, four had CHD, which yielded a penetrance rate of 40%. Sequence analysis of proband and her matrilineal relatives revealed the presence of a novel m.4420A>T variant and a m.10463T>C variant, both of which were highly conserved among various species. Structurally, the m.4420A>T variant had occurred at position 22 in the D-arm of tRNAMet, which disrupted the 13T-22A base-pairing, while the m.10463T>C variant was located at position 67 in the acceptor arm of tRNAArg, a position critical for steady-state level of the tRNA. Functional analysis revealed that patients with the m.4420A>T and m.10463T>C variants exhibited much fewer copy number of mtDNA and lower mitochondrial membrane potential (MMP) and ATP contents (P < 0.05), which were decreased by approximately 50.47%, 39.6% and 47.4%, respectively.@*CONCLUSION@#Mitochondrial tRNAMet 4420A>T and tRNAArg 10463T>C variants may underlay the maternally transmitted CHD in this pedigree, which had shown variation in mtDNA homogeneity, age of onset, clinical phenotype and other differences, suggesting that nuclear genes, environmental factors and mitochondrial genetic background have certain influence on the pathogenesis of CHD.

Recent advances in poly phosphate kinase (PPK) and the construction of PPK-mediated ATP regeneration system / 生物工程学报

Adenosine triphosphate (ATP) regeneration systems are essential for efficient biocatalytic phosphoryl transfer reactions. Polyphosphate kinase (PPK) is a versatile enzyme that can transfer phosphate groups among adenosine monophosphate (AMP), adenosine diphosphate (ADP), ATP, and polyphosphate (Poly P). Utilization of PPK is an attractive solution to address the problem of ATP regeneration due to its ability to use a variety of inexpensive and stable Poly P salts as phosphate group donors. This review comprehensively summarizes the structural characteristics and catalytic mechanisms of different types of PPKs, as well as the variations in enzyme activity, catalytic efficiency, stability, and coenzyme preference observed in PPKs from different sources. Moreover, recent advances in PPK-mediated ATP regeneration systems and protein engineering of wild-type PPK are summarized.

Effects of manipulating lactate dehydrogenase gene on metabolism of HEK-293 and production of human adenovirus / 生物工程学报

Reducing lactate accumulation has always been a goal of the mammalian cell biotechnology industry. When animal cells are cultured in vitro, the accumulation of lactate is mainly the combined result of two metabolic pathways. On one hand, glucose generates lactate under the function of lactate dehydrogenase A (LDHA); on the other hand, lactate can be oxidized to pyruvate by LDHB or LDHC and re-enter the TCA cycle. This study comprehensively evaluated the effects of LDH manipulation on the growth, metabolism and human adenovirus (HAdV) production of human embryonic kidney 293 (HEK-293) cells, providing a theoretical basis for engineering the lactate metabolism in mammalian cells. By knocking out ldha gene and overexpression of ldhb and ldhc genes, the metabolic efficiency of HEK-293 cells was effectively improved, and HAdV production was significantly increased. Compared with the control cell, LDH manipulation promoted cell growth, reduced the accumulation of lactate and ammonia, significantly enhanced the efficiency of substrate and energy metabolism of cells, and significantly increased the HAdV production capacity of HEK-293 cells. Among these LDH manipulation measures, ldhc gene overexpression performed the best, with the maximum cell density increased by about 38.7%. The yield of lactate to glucose and ammonia to glutamine decreased by 33.8% and 63.3%, respectively; and HAdV titer increased by at least 16 times. In addition, the ATP production rate, ATP/O2 ratio, ATP/ADP ratio and NADH content of the modified cell lines were increased to varying degrees, and the energy metabolic efficiency was significantly improved.

Manipulation of isocitrate dehydrogenase genes affects the anti-autolytic ability of lager yeast / 生物工程学报

Yeast autolysis affects the flavor and quality of beer. The regulation of yeast autolysis is a need for industrial beer production. Previous studies on brewer's yeast autolysis showed that the citric acid cycle-related genes had a great influence on yeast autolysis. To explore the contribution of isocitrate dehydrogenase genes in autolysis, the IDP1 and IDP2 genes were destroyed or overexpressed in typical lager yeast Pilsner. The destruction of IDP1 gene improved the anti-autolytic ability of yeast, and the anti-autolytic index after 96 h autolysis was 8.40, 1.5 times higher than that of the original strain. The destruction of IDP1 gene increased the supply of nicotinamide adenine dinucleotide phosphate (NADPH) and the NADPH/NADP+ ratio was 1.94. After fermentation, intracellular ATP level was 1.8 times higher than that of the original strain, while reactive oxygen species (ROS) was reduced by 10%. The destruction of IDP2 gene resulted in rapid autolysis and a decrease in the supply of NADPH. Anti-autolytic index after 96 h autolysis was 4.03 and the NADPH/NADP+ ratio was 0.89. After fermentation, intracellular ATP level was reduced by 8% compared with original strain, ROS was 1.3 times higher than that of the original strain. The results may help understand the regulation mechanism of citric acid cycle-related genes on yeast autolysis and provide a basis for the selection of excellent yeast with controllable anti-autolytic performance.

Rational design of polyphosphate kinase dual-substrate channel cavity for efficient production of glutathione by cell free catalysis / 生物工程学报

ATP is an important cofactor involved in many biocatalytic reactions that require energy input. Polyphosphate kinases (PPK) can provide energy for ATP-consuming reactions due to their cheap and readily available substrate polyphosphate. We selected ChPPK from Cytophaga hutchinsonii for substrate profiling and tolerance analysis. By molecular docking and site-directed mutagenesis, we rationally engineered the dual-substrate channel cavity of polyphosphate kinase to improve the catalytic activity of PPK. Compared with the wild type, the relative enzyme activity of the screened mutant ChPPKK81H-K103V increased by 326.7%. Meanwhile, the double mutation expanded the substrate utilization range and tolerance of ChPPK, and improved its heat and alkali resistance. Subsequently, we coupled the glutathione bifunctional enzyme GshAB and ChPPKK81H-K103V based on this ATP regeneration system, and glutathione was produced by cell-free catalysis upon disruption of cells. This system produced (25.4±1.9) mmol/L glutathione in 6 h upon addition of 5 mmol/L ATP. Compared with the system before mutation, glutathione production was increased by 41.9%. After optimizing the buffer, bacterial mass and feeding time of this system, (45.2±1.8) mmol/L glutathione was produced in 6 h and the conversion rate of the substrate l-cysteine was 90.4%. Increasing the ability of ChPPK enzyme to produce ATP can effectively enhance the conversion rate of substrate and reduce the catalytic cost, achieving high yield, high conversion rate and high economic value for glutathione production by cell-free catalysis. This study provides a green and efficient ATP regeneration system that may further power the ATP-consuming biocatalytic reaction platform.

Regulation of intracellular level of ATP and NADH in Escherichia coli to promote succinic acid production / 生物工程学报

Succinic acid is an important C4 platform chemical that is widely used in food, chemical, medicine sectors. The bottleneck of fermentative production of succinic acid by engineered Escherichia coli is the imbalance of intracellular cofactors, which often leads to accumulation of by-products, lower yield and low productivity. Stoichiometric analysis indicated that an efficient production of succinic acid by E. coli FMME-N-26 under micro-aeration conditions might be achieved when the TCA cycle provides enough ATP and NADH for the r-TCA pathway. In order to promote succinic acid production, a serial of metabolic engineering strategies include reducing ATP consumption, strengthening ATP synthesis, blocking NADH competitive pathway and constructing NADH complementary pathway were developed. As result, an engineered E. coli FW-17 capable of producing 139.52 g/L succinic acid and 1.40 g/L acetic acid in 5 L fermenter, which were 17.81% higher and 67.59% lower than that of the control strain, was developed. Further scale-up experiments were carried out in a 1 000 L fermenter, and the titer of succinic acid and acetic acid were 140.2 g/L and 1.38 g/L, respectively.

Neuroprotective effect of ginsenoside Re on drosophila model of Parkinson's disease / 中国中药杂志

This study aims to explore the neuroprotective mechanism of ginsenoside Re(GS-Re) on drosophila model of Parkinson's disease(PD) induced by rotenone(Rot). To be specific, Rot was used to induce PD in drosophilas. Then the drosophilas were grouped and respectively treated(GS-Re: 0.1, 0.4, 1.6 mmol·L~(-1); L-dopa: 80 μmol·L~(-1)). Life span and crawling ability of drosophilas were determined. The brain antioxidant activity [content of catalase(CAT), malondialdehyde(MDA), reactive oxygen species(ROS), superoxide dismutase(SOD)], dopamine(DA) content, and mitochondrial function [content of adenosine triphosphate(ATP), NADH:ubiquinone oxidoreductase subunit B8(NDUFB8) Ⅰ activity, succinate dehydrogenase complex, subunit B(SDHB) Ⅱ activity] were detected by enzyme-linked immunosorbent assay(ELISA). The number of DA neurons in the brains of drosophilas was measured with the immunofluorescence method. The levels of NDUFB8 Ⅰ, SDHB Ⅱ, cytochrome C(Cyt C), nuclear factor-E2-related factor 2(Nrf2), heme oxygenase-1(HO-1), B-cell lymphoma/leukemia 2(Bcl-2)/Bcl-2-assaciated X protein(Bax), and cleaved caspase-3/caspase-3 in the brain were detected by Western blot. The results showed that model group [475 μmol·L~(-1) Rot(IC_(50))] demonstrated significantly low survival rate, obvious dyskinesia, small number of neurons and low DA content in the brain, high ROS level and MDA content, low content of SOD and CAT, significantly low ATP content, NDUFB8 Ⅰ activity, and SDHB Ⅱ activity, significantly low expression of NDUFB8 Ⅰ, SDHB Ⅱ, and Bcl-2/Bax, large amount of Cyt C released from mitochondria to cytoplasm, low nuclear transfer of Nrf2, and significantly high expression of cleaved caspase-3/caspase-3 compared with the control group. GS-Re(0.1, 0.4, and 1.6 mmol·L~(-1)) significantly improved the survival rate of PD drosophilas, alleviated the dyskinesia, increased DA content, reduced the loss of DA neurons, ROS level, and MDA content in brain, improved content of SOD and CAT and antioxidant activity in brain, maintained mitochondrial homeostasis(significantly increased ATP content and activity of NDUFB8 Ⅰ and SDHB Ⅱ, significantly up-regulated expression of NDUFB8 Ⅰ, SDHB Ⅱ, and Bcl-2/Bax), significantly reduced the expression of Cyt C, increased the nuclear transfer of Nrf2, and down-regulated the expression of cleaved caspase-3/caspase-3. In conclusion, GS-Re can significantly relieve the Rot-induced cerebral neurotoxicity in drosophilas. The mechanism may be that GS-Re activates Keap1-Nrf2-ARE signaling pathway by maintaining mitochondrial homeostasis, improves antioxidant capacity of brain neurons, then inhibits mitochondria-mediated caspase-3 signaling pathway, and the apoptosis of neuronal cells, thereby exerting the neuroprotective effect.

Difference of lipid-lowering efficacy of "Xinjianqu" before and after fermentation and its mechanism based on LKB1-AMPK pathway and 16S rDNA sequencing technology / 中国中药杂志

On the basis of establishing the prescription of Xinjianqu and clarifying the increase of the lipid-lowering active ingredients of Xinjianqu by fermentation, this paper further compared the differences in the lipid-lowering effects of Xinjianqu before and after fermentation, and studied the mechanism of Xinjianqu in the treatment of hyperlipidemia. Seventy SD rats were randomly divided into seven groups, including normal group, model group, positive drug simvastatin group(0.02 g·kg~(-1)), and low-dose and high-dose Xinjianqu groups before and after fermentation(1.6 g·kg~(-1) and 8 g·kg~(-1)), with ten rats in each group. Rats in each group were given high-fat diet continuously for six weeks to establish the model of hyperlipidemia(HLP). After successful modeling, the rats were given high-fat diet and gavaged by the corresponding drugs for six weeks, once a day, to compare the effects of Xinjianqu on the body mass, liver coefficient, and small intestine propulsion rate of rats with HLP before and after fermentation. The effects of Xinjianqu before and after fermentation on total cholesterol(TC), triacylglyceride(TG), high-density lipoprotein cholesterol(HDL-C), low-density lipoprotein cholesterol(LDL-C), alanine aminotransferase(ALT), aspartate aminotransferase(AST), blood urea nitrogen(BUN), creatinine(Cr), motilin(MTL), gastrin(GAS), and the Na~+-K~+-ATPase levels were determined by enzyme-linked immunosorbent assay(ELISA). The effects of Xinjianqu on liver morphology of rats with HLP were investigated by hematoxylin-eosin(HE) staining and oil red O fat staining. The effects of Xinjianqu on the protein expression of adenosine 5'-monophosphate(AMP)-activated protein kinase(AMPK), phosphorylated AMPK(p-AMPK), liver kinase B1(LKB1), and 3-hydroxy-3-methylglutarate monoacyl coenzyme A reductase(HMGCR) in liver tissues were investigated by immunohistochemistry. The effects of Xinjianqu on the regulation of intestinal flora structure of rats with HLP were studied based on 16S rDNA high-throughput sequencing technology. The results showed that compared with those in the normal group, rats in the model group had significantly higher body mass and liver coefficient(P<0.01), significantly lower small intestine propulsion rate(P<0.01), significantly higher serum levels of TC, TG, LDL-C, ALT, AST, BUN, Cr, and AQP2(P<0.01), and significantly lower serum levels of HDL-C, MTL, GAS, Na~+-K~+-ATP levels(P<0.01). The protein expression of AMPK, p-AMPK, and LKB1 in the livers of rats in the model group was significantly decreased(P<0.01), and that of HMGCR was significantly increased(P<0.01). In addition, the observed＿otus, Shannon, and Chao1 indices were significantly decreased(P<0.05 or P<0.01) in rat fecal flora in the model group. Besides, in the model group, the relative abundance of Firmicutes was reduced, while that of Verrucomicrobia and Proteobacteria was increased, and the relative abundance of beneficial genera such as Ligilactobacillus and Lachnospiraceae＿NK4A136＿group was reduced. Compared with the model group, all Xinjianqu groups regulated the body mass, liver coefficient, and small intestine index of rats with HLP(P<0.05 or P<0.01), reduced the serum levels of TC, TG, LDL-C, ALT, AST, BUN, Cr, and AQP2, increased the serum levels of HDL-C, MTL, GAS, and Na~+-K~+-ATP, improved the liver morphology, and increased the protein expression gray value of AMPK, p-AMPK, and LKB1 in the liver of rats with HLP and decreased that of LKB1. Xinjianqu groups could regulate the intestinal flora structure of rats with HLP, increased observed＿otus, Shannon, Chao1 indices, and increased the relative abundance of Firmicutes, Ligilactobacillus(genus), Lachnospiraceae＿NK4A136＿group(genus). Besides, the high-dose Xinjianqu-fermented group had significant effects on body mass, liver coefficient, small intestine propulsion rate, and serum index levels of rats with HLP(P<0.01), and the effects were better than those of Xinjianqu groups before fermentation. The above results show that Xinjianqu can improve the blood lipid level, liver and kidney function, and gastrointestinal motility of rats with HLP, and the improvement effect of Xinjianqu on hyperlipidemia is significantly enhanced by fermentation. The mechanism may be related to AMPK, p-AMPK, LKB1, and HMGCR protein in the LKB1-AMPK pathway and the regulation of intestinal flora structure.

Shikonin induces hepatocellular carcinoma cell apoptosis by suppressing PKM2/PHD3/HIF-1α signaling pathway / 南方医科大学学报

OBJECTIVE@#To investigate the mechanism of shikonin-induced death of human hepatocellular carcinoma SMMC-7721 cells.@*METHODS@#Cultured SMMC-7721 cells and normal hepatocytes (L-02 cells) were treated with 4, 8, or 16 μmol/L shikonin, and the changes in cell viability was assessed using MTT assay. The levels of ATP and lactic acid in the cell cultures were detected using commercial kits. Co-immunoprecipitation and immunofluorescence staining were used to determine the relationship among pyruvate kinase M2 (PKM2), prolyl hydroxylase 3 (PHD3), and hypoxia-inducible factor-1α (HIF-1α). The expressions of PHD3, PKM2, HIF-1α, Bax, cleaved caspase-3, and Bcl-2 in SMMC-7721 cells were detected with Western blotting, and cell apoptosis was analyzed with annexin V-FITC/PI staining. The effects of RNA interference of PKM2 on PHD3 and HIF-1α expressions in SMMC-7721 cells were detected using Western blotting.@*RESULTS@#The IC50 of shikonin against SMMC-7721 and L-02 cells was 8.041 μmol/L and 31.75 μmol/L, respectively. Treatment with shikonin significantly inhibited the protein expressions of PKM2, HIF-1α and PHD3 and nuclear translocation of PKM2 and HIF-1α in SMMC-7721 cells. Coimmunoprecipitation and immunofluorescence staining confirmed that shikonin inhibited the formation of PKM2/PHD3/HIF-1α complex and significantly reduced the contents of lactic acid and ATP in SMMC-7721 cells (P < 0.05). The expressions of PHD3 and HIF-1α decreased significantly after PKM2 knockdown (P < 0.05). Shikonin treatment significantly increased the apoptosis rate, enhanced the expressions of Bax and cleaved caspase-3, and decreased Bcl-2 expression in SMMC-7721 cells (P < 0.05).@*CONCLUSIONS@#Shikonin induces apoptosis of SMMC-7721 cells possibly by inhibiting aerobic glycolysis through the PKM2/PHD3/HIF-1α signaling pathway to cause energy supply dysfunction in the cells.

Clinical application value of Huanglian Jiedu Pills in improving syndrome of excess heat and fire toxin based on phase Ⅱ clinical trial study on plasma ATP, 4-HNE, and ACTH levels / 中国中药杂志

A randomized, double-blind, placebo-controlled, multi-center phase Ⅱ clinical trial design was used in this study to recruit subjects who were in line with the syndrome of excess heat and fire toxin, and were diagnosed as recurrent oral ulcers, gingivitis, and acute pharyngitis. A total of 240 cases were included and randomly divided into a placebo group and a Huanglian Jiedu Pills group. The clinical efficacy of Huanglian Jiedu Pills in treating the syndrome of excess heat and fire toxin was evaluated by using the traditional Chinese medicine(TCM) syndrome scale. Enzyme-linked immunosorbent assay(ELISA) was used to determine and evaluate the levels of adenosine triphosphate(ATP), 4-hydroxynonenal(4-HNE), and adrenocorticotropic hormone(ACTH) in plasma of the two groups before and after administration and to predict their application value as clinical biomarkers. The results showed that the disappearance rate of main symptoms in the Huanglian Jiedu Pills group was 69.17%, and that in the placebo group was 50.83%. The comparison between the Huanglian Jiedu Pills group and the placebo group showed that 4-HNE before and after administration was statistically significant(P<0.05). The content of 4-HNE in the Huanglian Jiedu Pills group decreased significantly after administration(P<0.05), but that in the placebo group had no statistical significance and showed an upward trend. After administration, the content of ATP in both Huanglian Jiedu Pills group and placebo group decreased significantly(P<0.05), indicating that the energy metabolism disorder was significantly improved after administration of Huanglian Jiedu Pills and the body's self-healing ability also alleviated the increase in ATP level caused by the syndrome of excess heat and fire toxin to a certain extent. ACTH in both Huanglian Jiedu Pills group and placebo group decreased significantly after administration(P<0.05). It is concluded that Huanglian Jiedu Pills has a significant clinical effect, and can significantly improve the abnormal levels of ATP and 4-HNE in plasma caused by the syndrome of excess heat and fire toxin, which are speculated to be the effective clinical biomarkers for Huanglian Jiedu Pills to treat the syndrome of excess heat and fire toxin.

Excess Oxygen Supply for Different Time Periods Affect Energy Metabolism in Rat Alveolar Epithelial Type Ⅱ Cells / 中国医学科学院学报

Objective To observe the effect of excess oxygen supply for different time periods on the mitochondrial energy metabolism in alveolar epithelial type Ⅱ cells. Methods Rat RLE-6TN cells were assigned into a control group (21% O2 for 4 h) and excess oxygen supply groups (95% O2 for 1,2,3,and 4 h,res-pectively).The content of adenosine triphosphate (ATP),the activity of mitochondrial respiratory chain complex V,and the mitochondrial membrane potential were determined by luciferase assay,micro-assay,and fluorescent probe JC-1,respectively.Real-time fluorescence quantitative PCR was employed to determine the mRNA levels of NADH dehydrogenase subunit 1 (ND1),cytochrome b (Cytb),cytochrome C oxidase subunit I (COXI),and adenosine triphosphatase 6 (ATPase6) in the core subunits of mitochondrial respiratory chain complexes Ⅰ,Ⅲ,Ⅳ,and Ⅴ,respectively. Results Compared with the control group,excess oxygen supply for 1,2,3,and 4 h down-regulated the mRNA levels of ND1 (q=24.800,P<0.001;q=13.650,P<0.001;q=9.869,P<0.001;q=20.700,P<0.001),COXI (q=16.750,P<0.001;q=10.120,P<0.001;q=8.476,P<0.001;q=14.060,P<0.001),and ATPase6 (q=22.770,P<0.001;q=15.540,P<0.001;q=12.870,P<0.001;q=18.160,P<0.001).Moreover,excess oxygen supply for 1 h and 4 h decreased the ATPase activity (q=9.435,P<0.001;q=11.230,P<0.001) and ATP content (q=5.615,P=0.007;q=5.029,P=0.005).The excess oxygen supply for 2 h and 3 h did not cause significant changes in ATPase activity (q=0.156,P=0.914;q=3.197,P=0.116) and ATP content (q=0.859,P=0.557;q=1.273,P=0.652).There was no significant difference in mitochondrial membrane potential among the groups (F=0.303,P=0.869). Conclusion Short-term excess oxygen supply down-regulates the expression of the core subunits of mitochondrial respiratory chain complexes and reduces the activity of ATPase,leading to the energy metabolism disorder of alveolar epithelial type Ⅱ cells.

A comprehensive review of natural products with anti-hypoxic activity / 中国天然药物

Natural products exhibit substantial impacts in the field of anti-hypoxic traetment. Hypoxia can cause altitude sickness and other negative effect on the body. Headache, coma, exhaustion, vomiting and, in severe cases, death are some of the clinical signs. Currently, hypoxia is no longer just a concern in plateau regions; it is also one of the issues that can not be ignored by urban residents. This review covered polysaccharides, alkaloids, saponins, flavonoids, peptides and traditional Chinese compound prescriptions as natural products to protect against hypoxia. The active ingredients, effectiveness and mechanisms were discussed. The related anti-hypoxic mechanisms involve increasing the hemoglobin (HB) content, glycogen content and adenosine triphosphate (ATP) content, removing excessive reactive oxygen species (ROS), reducing lipid peroxidation, regulating the levels of related enzymes in cells, protecting the structural and functional integrity of the mitochondria and regulating the expression of apoptosis-related genes. These comprehensive summaries are beneficial to anti-hypoxic research and provide useful information for the development of anti-hypoxic products.

Potentilla anserina polysaccharide alleviates cadmium-induced oxidative stress and apoptosis of H9c2 cells by regulating the MG53-mediated RISK pathway / 中国天然药物

Oxidative stress plays a crucial role in cadmium (Cd)-induced myocardial injury. Mitsugumin 53 (MG53) and its mediated reperfusion injury salvage kinase (RISK) pathway have been demonstrated to be closely related to myocardial oxidative damage. Potentilla anserina L. polysaccharide (PAP) is a polysaccharide with antioxidant capacity, which exerts protective effect on Cd-induced damage. However, it remains unknown whether PAP can prevent and treat Cd-induced cardiomyocyte damages. The present study was desgined to explore the effect of PAP on Cd-induced damage in H9c2 cells based on MG53 and the mediated RISK pathway. For in vitro evaluation, cell viability and apoptosis rate were analyzed by CCK-8 assay and flow cytometry, respectively. Furthermore, oxidative stress was assessed by 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA) staining and using superoxide dismutase (SOD), catalase (CAT), and glutathione/oxidized glutathione (GSH/GSSG) kits. The mitochondrial function was measured by JC-10 staining and ATP detection assay. Western blot was performed to detect the expression of proteins related to MG53, the RISK pathway, and apoptosis. The results indicated that Cd increased the levels of reactive oxygen species (ROS) in H9c2 cells. Cd decreased the activities of SOD and CAT and the ratio of GSH/GSSG, resulting in decreases in cell viability and increases in apoptosis. Interestingly, PAP reversed Cd-induced oxidative stress and cell apoptosis. Meanwhile, Cd reduced the expression of MG53 in H9c2 cells and inhibited the RISK pathway, which was mediated by decreasing the ratio of p-AktSer473/Akt, p-GSK3βSer9/GSK3β and p-ERK1/2/ERK1/2. In addition, Cd impaired mitochondrial function, which involved a reduction in ATP content and mitochondrial membrane potential (MMP), and an increase in the ratio of Bax/Bcl-2, cytoplasmic cytochrome c/mitochondrial cytochrome c, and Cleaved-Caspase 3/Pro-Caspase 3. Importantly, PAP alleviated Cd-induced MG53 reduction, activated the RISK pathway, and reduced mitochondrial damage. Interestingly, knockdown of MG53 or inhibition of the RISK pathway attenuated the protective effect of PAP in Cd-induced H9c2 cells. In sum, PAP reduces Cd-induced damage in H9c2 cells, which is mediated by increasing MG53 expression and activating the RISK pathway.

Cryo-EM structures for the Mycobacterium tuberculosis iron-loaded siderophore transporter IrtAB

The adenosine 5'-triphosphate (ATP)-binding cassette (ABC) transporter, IrtAB, plays a vital role in the replication and viability of Mycobacterium tuberculosis (Mtb), where its function is to import iron-loaded siderophores. Unusually, it adopts the canonical type IV exporter fold. Herein, we report the structure of unliganded Mtb IrtAB and its structure in complex with ATP, ADP, or ATP analogue (AMP-PNP) at resolutions ranging from 2.8 to 3.5 Å. The structure of IrtAB bound ATP-Mg2+ shows a "head-to-tail" dimer of nucleotide-binding domains (NBDs), a closed amphipathic cavity within the transmembrane domains (TMDs), and a metal ion liganded to three histidine residues of IrtA in the cavity. Cryo-electron microscopy (Cryo-EM) structures and ATP hydrolysis assays show that the NBD of IrtA has a higher affinity for nucleotides and increased ATPase activity compared with IrtB. Moreover, the metal ion located in the TM region of IrtA is critical for the stabilization of the conformation of IrtAB during the transport cycle. This study provides a structural basis to explain the ATP-driven conformational changes that occur in IrtAB.

Triggering of Major Brain Disorders by Protons and ATP: The Role of ASICs and P2X Receptors / 神经科学通报·英文版

Adenosine triphosphate (ATP) is well-known as a universal source of energy in living cells. Less known is that this molecule has a variety of important signaling functions: it activates a variety of specific metabotropic (P2Y) and ionotropic (P2X) receptors in neuronal and non-neuronal cell membranes. So, a wide variety of signaling functions well fits the ubiquitous presence of ATP in the tissues. Even more ubiquitous are protons. Apart from the unspecific interaction of protons with any protein, many physiological processes are affected by protons acting on specific ionotropic receptors-acid-sensing ion channels (ASICs). Both protons (acidification) and ATP are locally elevated in various pathological states. Using these fundamentally important molecules as agonists, ASICs and P2X receptors signal a variety of major brain pathologies. Here we briefly outline the physiological roles of ASICs and P2X receptors, focusing on the brain pathologies involving these receptors.

Asiatic acid improves insulin secretion of β cells in type 2 diabetes through TNF- α/Mfn2 pathway / 浙江大学学报·医学版

OBJECTIVES@#To investigate the effects and molecular mechanisms of asiatic acid on β-cell function in type 2 diabetes mellitus (T2DM).@*METHODS@#The T2DM model was established by high fat diet and streptozotocin injection in ICR mice, and the effects of asiatic acid on glucose regulation were investigated in model mice. The islets were isolated from palmitic acid-treated diabetic mice. ELISA was used to detect the glucose-stimulated insulin secretion, tumor necrosis factor (TNF)-α and interleukin (IL)-6. ATP assay was applied to measure ATP production, and Western blotting was used to detect protein expression of mature β cell marker urocortin (Ucn) 3 and mitofusin (Mfn) 2. The regulatory effects of asiatic acid on glucose-stimulated insulin secretion (GSIS) and Ucn3 expression were also investigated after siRNA interference with Mfn2 or treatment with TNF-α.@*RESULTS@#Asiatic acid with the dose of 25 mg·kg－1·d－1 had the best glycemic control in T2DM mice and improved the homeostasis model assessment β index. Asiatic acid increased the expression of Mfn2 and Ucn3 protein and improved the GSIS function of diabetic β cells in vitro and in vivo (both P<0.05). Moreover, it improved the ATP production of islets of T2DM mice in vitro (P<0.05). Interfering Mfn2 with siRNA blocked the up-regulation of Ucn3 and GSIS induced by asiatic acid. Asiatic acid inhibited islet TNF-α content and increased Mfn2 and Ucn3 protein expression inhibited by TNF-α.@*CONCLUSIONS@#Asiatic acid improves β cell insulin secretion function in T2DM mice by maintaining the β cell maturity, which may be related to the TNF-α/Mfn2 pathway.

The preventive effect of exogenous adenosine triphosphate on methanol-induced cardiotoxicity in rats

Abstract Exposure to methanol can cause serious consequences such as permanent visual disturbances and death. The heart tissue is highly vulnerable to ATP deficiency. Our study aimed to investigate whether exogenous ATP administration may alleviate methanol-induced ATP deficiency and subsequent oxidative damage in rat heart tissue. A total of 30 rats were divided into equal five groups; Healthy Group (HG), Methotrexate (MXG), Methanol (MeOH), Methotrexate+Methanol (MXM), and Methotrexate+Methanol+ATP (MMA) groups. We inhibited tetrahydrofolate synthesis by methotrexate to induce methanol toxicity. Methotrexate was administered to MXG, MXM, and MMA group animals for seven days with a catheter directly to the stomach at a 0,3 mg/kg dose per day. At the end of this period, % 20 methanol at a dose of 3 g/kg was administered to MeOH, MMA and MXM group animals. Immediately after methanol application, MMA group animals were injected with ATP at a 4 mg/kg dose intraperitoneally. Blood samples and heart tissues were used for biochemical analysis and histopathological examination. Co-exposure to methanol and methotrexate substantially exacerbated cardiac damage, indicating the potent cardiotoxic effects of methanol. However, the administration of exogenous ATP to MMA group animals brought biochemical oxidative damage parameters and histopathological findings closer to HG.

Clinical and genetic analysis of essential hypertension with CYB gene m.15024G>A mutation / 浙江大学学报·医学版

OBJECTIVES@#To explore the role of mitochondrial CYB 15024G>A mutation in the development of essential hypertension.@*METHODS@#Mitochondrial genome sequences of hypertensive patients were obtained from previous studies. Clinical and genetic data of a hypertensive patient with mitochondrial CYB 15024G>A mutation and its pedigree were analyzed. Lymphocytes derived from patient and family members were transformed into immortalized lymphoblastoid cell lines, and the levels of adenosine triphosphate (ATP), mitochondrial membrane potential and intracellular reactive oxygen species (ROS) were detected.@*RESULTS@#The penetrance of this essential hypertension family was 42.9%, and the age of onset was 46-68 years old. Mitochondrial genome sequencing results showed that all maternal members carried a highly conserved mitochondrial CYB 15024G>A mutation. This mutation could affect the free energy of mitochondrial CYB for secondary and tertiary structure and protein folding, thereby changing its structural stability and the structure of the electron transfer function area around the mutation site. Compared with the control, the cell line carrying the mitochondrial CYB 15024G>A mutation showed significantly decreased levels of mitochondrial CYB, ATP and mitochondrial membrane potential, and increased levels of ROS (P<0.01).@*CONCLUSIONS@#Mitochondrial CYB 15024G>A mutation may affect the structure of respiratory chain subunits and mitochondrial function, leading to cell dysfunction, which suggests that the mutation may play a synergistic role in essential hypertension.