Histidine re-sensitizes pediatric acute lymphoblastic leukemia to 6-mercaptopurine through tetrahydrofolate consumption and SIRT5-mediated desuccinylation.

Despite progressive improvements in the survival rate of pediatric B-cell lineage acute lymphoblastic leukemia (B-ALL), chemoresistance-induced disease progression and recurrence still occur with poor prognosis, thus highlighting the urgent need to eradicate drug resistance in B-ALL. The 6-mercaptopurine (6-MP) is the backbone of ALL combination chemotherapy, and resistance to it is crucially related to relapse. The present study couples chemoresistance in pediatric B-ALL with histidine metabolism deficiency. Evidence was provided that histidine supplementation significantly shifts the 6-MP dose-response in 6-MP-resistant B-ALL. It is revealed that increased tetrahydrofolate consumption via histidine catabolism partially explains the re-sensitization ability of histidine. More importantly, this work provides fresh insights into that desuccinylation mediated by SIRT5 is an indispensable and synergistic requirement for histidine combination therapy against 6-MP resistance, which is undisclosed previously and demonstrates a rational strategy to ameliorate chemoresistance and protect pediatric patients with B-ALL from disease progression or relapse.

A predictive model of response to metoprolol in children and adolescents with postural tachycardia syndrome.

BACKGROUND: The present work was designed to explore whether electrocardiogram (ECG) index-based models could predict the effectiveness of metoprolol therapy in pediatric patients with postural tachycardia syndrome (POTS). METHODS: This study consisted of a training set and an external validation set. Children and adolescents with POTS who were given metoprolol treatment were enrolled, and after follow-up, they were grouped into non-responders and responders depending on the efficacy of metoprolol. The difference in pre-treatment baseline ECG indicators was analyzed between the two groups in the training set. Binary logistic regression analysis was further conducted on the association between significantly different baseline variables and therapeutic efficacy. Nomogram models were established to predict therapeutic response to metoprolol. The receiver-operating characteristic curve (ROC), calibration, and internal validation were used to evaluate the prediction model. The predictive ability of the model was validated in the external validation set. RESULTS: Of the 95 enrolled patients, 65 responded to metoprolol treatment, and 30 failed to respond. In the responders, the maximum value of the P wave after correction (Pcmax), P wave dispersion (Pd), Pd after correction (Pcd), QT interval dispersion (QTd), QTd after correction (QTcd), maximum T-peak-to-T-end interval (Tpemax), and T-peak-to-T-end interval dispersion (Tped) were prolonged (all P < 0.01), and the P wave amplitude was increased (P < 0.05) compared with those of the non-responders. In contrast, the minimum value of the P wave duration after correction (Pcmin), the minimum value of the QT interval after correction (QTcmin), and the minimum T-peak-to-T-end interval (Tpemin) in the responders were shorter (P < 0.01, < 0.01 and < 0.01, respectively) than those in the non-responders. The above indicators were screened based on the clinical significance and multicollinearity analysis to construct a binary logistic regression. As a result, pre-treatment Pcmax, QTcmin, and Tped were identified as significantly associated factors that could be combined to provide an accurate prediction of the therapeutic response to metoprolol among the study subjects, yielding good discrimination [area under curve (AUC) = 0.970, 95% confidence interval (CI) 0.942-0.998] with a predictive sensitivity of 93.8%, specificity of 90.0%, good calibration, and corrected C-index of 0.961. In addition, the calibration curve and standard curve had a good fit. The accuracy of internal validation with bootstrap repeated sampling was 0.902. In contrast, the kappa value was 0.769, indicating satisfactory agreement between the predictive model and the results from the actual observations. In the external validation set, the AUC for the prediction model was 0.895, and the sensitivity and specificity were 90.9% and 95.0%, respectively. CONCLUSIONS: A high-precision predictive model was successfully developed and externally validated. It had an excellent predictive value of the therapeutic effect of metoprolol on POTS among children and adolescents.

Progress on lncRNA regulated disease resistance traits in domesticated animals.

Long non-coding RNA (lncRNA) is a class of non-coding RNAs with a length greater than 200 nucleotides. Although lncRNAs do not have any protein coding capability, they can affect the phenotypes of traits by influencing gene expression through transcriptional regulation, post-transcriptional regulation, and epigenetic modification. In modern animal husbandry production, besides increasing growth and yield traits, investigations on the regulation mechanisms of immune factors, cytokines and other disease resistance-related indicators and traits are particularly important for improving the health and welfare of domesticated animals as well as public health. In recent years, researchers have made significant progress in understanding the regulatory mechanisms of lncRNA on the disease resistance traits of chickens (Gallus gallus), pigs (Sus scrofa), cattle (Bos taurus) and other important domesticated animals, thereby laying the basic foundation for the translational application of epigenetic markers in breeding of animals with disease resistance. In this review, we briefly introduce the biological functions and the origins of lncRNAs, then focus on the research progress on the regulatory effects of lncRNAs on disease resistance traits of domesticated animals, and thus providing the scientific basis for the research of lncRNA and its application in the breeding of disease-resistant animals.

Viperin_sv1 promotes RIG-I expression and suppresses SVCV replication through its radical SAM domain.

SVCV infection is known to activate the host's innate immune responses, including the production of interferon (IFN) and interferon-stimulated genes (ISGs). Viperin_sv1 is a novel splice variant of viperin, which is induced during SVCV infection and proves to positively regulate the IFN activation and production. However, the underlying mechanism remains unsolved. In this study, the P protein of SVCV was identified to be the key to induce the mRNA modification and production of viperin_sv1 during the virus infection. Besides, Viperin_sv1 was able to trigger the RLR signaling cascades to activate type-1 interferon response. Additional analysis revealed that viperin_sv1 promoted the stability and function of RIG-I, which result in the production of IFN and ISGs. Moreover, the central SAM domain of viperin_sv1 was demonstrated to be essential for regulating RIG-I protein expression and inducing IFN production. Furthermore, this study also showed that SVCV replication could be inhibited by the viperin_sv1 SAM domain. In conclusion, our study demonstrates that viperin_sv1 reduces the replication of SVCV by promoting the RIG-I protein expression. Our findings identified the antiviral function played by the SAM domain of viperin_sv1 and suggested an antiviral mechanism that is conserved among different species.

Gating Properties of Mutant Sodium Channels and Responses to Sodium Current Inhibitors Predict Mexiletine-Sensitive Mutations of Long QT Syndrome 3.

BACKGROUND: Long QT syndrome 3 (LQT3) is caused by SCN5A mutations. Late sodium current (late I Na) inhibitors are current-specific to treat patients with LQT3, but the mechanisms underlying mexiletine (MEX) -sensitive (N1325S and R1623Q) and -insensitive (M1652R) mutations remains to be elucidated. METHODS: LQT3 patients with causative mutations were treated with oral MEX following i.v. lidocaine. Whole-cell patch-clamp techniques and molecular remodeling were used to determine the mechanisms underlying the sensitivity to MEX. RESULTS: Intravenous administration of lidocaine followed by MEX orally in LQT patients with N1325S and R1623Q sodium channel mutation shortened QTc interval, abolished arrhythmias, and completely normalized the ECG. In HEK293 cells, the steady-state inactivation curves of the M1652R channels were rightward shifted by 5.6 mV relative to the WT channel. In contrast, the R1623Q mutation caused a leftward shift of the steady-state inactivation curve by 15.2 mV compared with WT channel, and N1325S mutation did not affect steady-state inactivation (n = 5-13, P < 0.05). The extent of the window current was expanded in all three mutant channels compared with WT. All three mutations increased late I Na with the greatest amplitude in the M1652R channel (n = 9-15, P < 0.05). MEX caused a hyperpolarizing shift of the steady-state inactivation and delayed the recovery of all three mutant channels. Furthermore, it suppressed late I Na in N1325S and R1623Q to a greater extent compared to that of M1652R mutant channel. Mutations altered the sensitivity of Nav1.5 to MEX through allosteric mechanisms by changing the conformation of Nav1.5 to become more or less favorable for MEX binding. Late I Na inhibitors suppressed late I Na in N1325S and R1623Q to a greater extent than that in the M1652R mutation (n = 4-7, P < 0.05). CONCLUSION: The N1325S, R1623Q, and M1652R mutations are associated with a variable augmentation of late I Na, which was reversed by MEX. M1652R mutation changes the conformation of Nav1.5 that disrupt the inactivation of channel affecting MEX binding, corresponding to the poor response to MEX. The lidocaine test, molecular modeling, and drugs screening in cells expressing mutant channels are useful for predicting the effectiveness of late I Na inhibitors.

Prediction of intravenous immunoglobulin resistance in Kawasaki disease in children.

BACKGROUND: We aimed to explore predictive measures for intravenous immunoglobulin (IVIG) resistance in children with Kawasaki disease (KD). METHODS: Patients diagnosed with KD were enrolled in this study. Univariate analysis and multiple logistic regression were utilized to analyze the clinical features and laboratory results prior to IVIG-treatment of the two groups. Independent predictors of IVIG resistance were analyzed, and a predictive model for KD children with IVIG resistance was constructed. RESULTS: A total of 277 children with KD, 180 boys and 97 girls, aged 2-128 (median 23) months, were enrolled in the study. Compared with the IVIG-responsive group, the IVIG-resistant group had higher levels of the peripheral neutrophil count, mean platelet volume, mean platelet volume-to-lymphocyte ratio and C-reactive protein, and total serum bilirubin, but lower levels of peripheral lymphocyte count, serum albumin and serum prealbumin. Age (in months), peripheral neutrophil count, lymphocyte count and mean platelet volume and serum albumin were independent indicators for IVIG resistance by multivariate logistic regression analysis. A logistic regression model and a scoring system were set up, where cut-off values of - 0.46 and 6.5 points yielded sensitivities of 83.9% and 77.4%, and specificities of 74.8% and 61.0%, respectively. The areas under the curve (AUC) were 0.808 in the logistic regression model, and 0.750 in the scoring system. CONCLUSION: Our model for predicting IVIG-resistant children with KD, involving age (months), peripheral neutrophil count, lymphocyte count and mean platelet volume and serum albumin prior to IVIG-treatment, is helpful for clinical prediction of children with IVIG-resistant KD.

Effect of Corilagin on the Proliferation and NF-κB in U251 Glioblastoma Cells and U251 Glioblastoma Stem-Like Cells.

Background. This study is to explore the effect of corilagin on the proliferation and NF-κB signaling pathway in U251 glioblastoma cells and U251 glioblastoma stem-like cells. Methods. CD133 positive U251 glioblastoma cells were separated by immunomagnetic beads to isolate glioblastoma stem-like cells. U251 cells and stem-like cells were intervened by different corilagin concentrations (0, 25, 50, and 100 µg/mL) for 48 h, respectively. Cell morphology, cell counting kit-8 assay, flow cytometry, dual luciferase reporter assay, and a western blot were used to detect and analyze the cell proliferation and cell cycle and investigate the expression of IKBα protein in cytoplasm and NF-κB/p65 in nucleus. Results. Corilagin inhibited the cell proliferation of U251 cells and their stem-like cells and the inhibition role was stronger in U251 stem-like cells (P < 0.05). The cell cycle was arrested at G2/M phase in the U251 cells following corilagin intervention; the proportion of cells in G2/M phase increased as the concentration of corilagin increased (P < 0.05). The U251 stem-like cells were arrested at the S phase following treatment with corilagin; the proportion of cells in the S phase increased as the concentration of corilagin increased (P < 0.05). The ratio of dual luciferase activities of U251 stem-like cells was lower than that of U251 cells in the same corilagin concentration. With increasing concentrations of corilagin, the IKBα expression in cytoplasm of U251 cells and U251 stem-like cells was increased, but the p65 expression in nucleus of U251 cells and U251 stem-like cells was decreased (P < 0.05). Conclusion. Corilagin can inhibit the proliferation of glioblastoma cells and glioblastoma stem-like cells; the inhibition on glioblastoma stem-like cell proliferation is stronger than glioblastoma cells. This different result indicates that the effect of corilagin on U251 cells and U251 stem-like cells may have close relationships with mechanism of cell cycle and NF-κB signaling pathway; however, the real antitumor mechanism of corilagin is not yet clear and requires further study.

[Biological Effects of ZnO Nanoparticles as Influenced by Arbuscular Mycorrhizal Inoculation and Phosphorus Fertilization].

ZnO nanoparticles (NPs) are widely used in many applications, such as plastics, ceramics, glass, cement, rubber, lubricants, paints, pigments, batteries, fire retardants, catalysts, and anti-microbial agents. They directly or indirectly enter aquatic and terrestrial environments through application, accidental release, contaminated soil/sediments, or atmospheric fallouts. When present in excess, ZnO NPs can induce phytotoxicity and reduce plant growth and yields. ZnO NPs can also cause Zn accumulation in edible parts of food crops, and then subsequently enter human bodies and pose a significant health risk. Arbuscular mycorrhizae are ubiquitous symbiotic associations in nature formed between arbuscular mycorrhizal (AM) fungi and most higher plants in terrestrial ecosystems. In addition to their well-known contribution to plant nutrient acquisition and growth, AM fungi can improve plant tolerance to various environmental stresses, but mycorrhizal effects vary with environmental conditions such as phosphorus status in both soil and plants. AM fungi have been shown to alleviate the negative effects of ZnO NPs and zinc accumulation in plants, however, the role of phosphorus fertilization has been neglected. A greenhouse pot culture experiment was conducted using maize as the test plant inoculated with or without AM fungus Funneliformis mosseae. Four levels of phosphorus (0, 20, 50 or 100 mg·kg-1) and two levels of ZnO NPs (0 or 500 mg·kg-1) were applied to pots. Shoots and roots were harvested separately after two months of growth. Mycorrhizal infection, plant biomass, P and Zn concentrations and uptake in plants, and soil DTPA-extractable zinc and pH were determined. The results showed that ZnO NPs did not significantly affect the growth of maize, but inhibited root mycorrhizal infection and plant phosphorus uptake, and led to the accumulation of zinc in plants. ZnO NPs and high phosphorus supply decreased root mycorrhizal infection, but AM inoculation significantly promoted plant growth under all phosphorus supply levels. Phosphorus application and AM inoculation increased soil pH, but reduced the bioavailability of Zn derived from ZnO NPs, decreased the translocation and accumulation of zinc in maize shoots, and thus produced beneficial effects on plants. In general, AM inoculation showed positive mycorrhizal effect, especially under low phosphorus conditions and addition of ZnO NPs. Our results showed for the first time that both AM fungi and phosphate fertilizer could help to mitigate soil pollution and the ecological and health risks posed by ZnO NPs.

Mulberry Transcription Factor MnDREB4A Confers Tolerance to Multiple Abiotic Stresses in Transgenic Tobacco.

The dehydration responsive element binding (DREB) transcription factors have been reported to be involved in stress responses. Most studies have focused on DREB genes in subgroups A-1 and A-2 in herbaceous plants, but there have been few reports on the functions of DREBs from the A-3-A-6 subgroups and in woody plants. Moreover, mulberry trees are ecologically and economically important perennial woody plants, but there has been little research on its stress physiology, biochemistry and molecular biology. In this study, a DREB gene from the mulberry tree, designated as MnDREB4A, classified into the A-4 subgroup by our previous study, was selected for further characterization. Our results showed that the MnDREB4A protein was localized to the nucleus where it activated transcription. The promoter of MnDREB4A can direct prominent expression downstream of the ß-glucuronidase (GUS) gene under heat, cold, drought and salt stress, and GUS staining was deepest after 12 h of stress treatment. The MnDREB4A-overexpression transgenic tobacco showed the improved growth phenotype under untreated conditions, such as greener leaves, longer roots, and lower water loss and senescence rates. Overexpression of MnDREB4A in tobacco can significantly enhance tolerance to heat, cold, drought, and salt stresses in transgenic plants. The leaf discs and seedlings of transgenic plants reduced leaf wilting and senescence rates compared to the wild type plants under the different stress conditions. Further investigation showed that transgenic plants also had higher water contents and proline contents, and lower malondialdehyde contents under untreated condition and stress conditions. Our results indicate that the MnDREB4A protein plays an important role in plant stress tolerance.

[Clinical analysis and follow-up study of cardiavascular system involvement in 10 children with methylmalonic aciduria combined with hyperhomocysteinemia].

OBJECTIVE: To study the clinical features and treatment outcomes of cardiovascular system involvement in children with methylmalonic aciduria combined with hyperhomocysteinemia (MMACHC). METHODS: The clinical data of 10 children with methylmalonic aciduria combined with hyperhomocysteinemia and who had cardiovascular system involvement were retrospectively analyzed and the treatment outcomes were followed up. RESULTS: In the 10 patients, there were 4 cases with initial presentations of cardiovascular system symptoms such as shortness of breath and dyspnea, 3 cases with urinary tract symptoms such as edema, hematuria and proteinuria, and 3 cases with nervous system symptoms such as developmental retardation and convulsions. The 10 patients had different types and severity of cardiovascular injuries. After 3 months to 8 years of follow-up, the congenital heart defects resolved naturally in 2 cases, and the patient with arrhythmia had no obvious changes. In 5 cases of hypertension, blood pressures recovered to normal in 3 cases, and 1 case was lost to follow-up. In 5 patients with pulmonary hypertension, 2 died, 2 recovered, and 1 case had mildly elevated pulmonary artery pressure. Seven patients underwent MMACHC gene testing, and 5 showed c.80A>G mutations. CONCLUSIONS: Metabolic disease should be taken into account for the children with unexplained pulmonary hypertension and hypertension with the onset of the shortness of breath and dyspnea. The severity of cardiovascular system involvement might be one of the most important factors affecting the prognosis of children with MMACHC. Cardiavascular system involvement of the patients may be related to MMACHC c.80A>G mutations.

Transcriptome analysis and microsatellite discovery in the blunt snout bream (Megalobrama amblycephala) after challenge with Aeromonas hydrophila.

The blunt snout bream, Megalobrama amblycephala, is a herbivorous freshwater fish species native to China and a major aquaculture species in Chinese freshwater polyculture systems. In recent years, the bacterium Aeromonas hydrophila has been reported to be its pathogen causing great losses of farmed fish. To understand the immune response of the blunt snout bream to A. hydrophila infection, we used the Solexa/Illumina technology to analyze the transcriptomic profile after artificial bacterial infection. Two nonnormalized cDNA libraries were synthesized from tissues collected from control blunt snout bream or those injected with A. hydrophila. After assembly, 155,052 unigenes (average length 692.8 bp) were isolated. All unigenes were annotated using BLASTX relative to several public databases: the National Center for Biotechnology Information nonreduntant (Nr) database, SwissProt, Eukaryotic Orthologous Groups of proteins (KOG), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Gene Ontology (GO). The sequence similarity (86%) of the assembled unigenes was to zebrafish based on the Nr database. A number of unigenes (n = 30,482) were assigned to three GO categories: biological processes (25,242 unigenes), molecular functions (26,096 unigenes), and cellular components (22,778 unigenes). 20,909 unigenes were classified into 25 KOG categories and 28,744 unigenes were assigned into 315 specific signaling pathways. In total, 238 significantly differentially expressed unigenes (mapped to 125 genes) were identified: 101 upregulated genes and 24 downregulated genes. Another 303 unigenes were mapped to unknown or novel genes. Among the known expressed genes identified, 53 were immune-related genes and were distributed in 71 signaling pathways. The expression patterns of selected up- and downregulated genes from the control and injected groups were determined with reverse transcription-quantitative PCR (RT-qPCR). Microsatellites (n = 10,877), including di-to pentanucleotide repeat motifs, were also identified in the blunt snout bream transcriptome profiles. This study extends our understanding of the immune defense mechanisms of the blunt snout bream against A. hydrophila and provides useful data for further studies of the immunogenetics of this species.

Decreased expression of matrix metalloproteinase-1 in the maternal umbilical serum, trophoblasts and decidua leads to preeclampsia.

The aim of the present study was to explore the levels of matrix metalloproteinase-1 (MMP-1) and tissue inhibitor of metalloproteinase-1 (TIMP-1) in the maternal umbilical serum, placenta and decidua of patients with preeclampsia compared with those in normotensive pregnant females. A total of 73 pregnant females were recruited as the test subjects, including 43 inpatients with hypertensive disorders in pregnancy and 30 normal pregnant females as the control. The 43 inpatients with hypertensive disorders in pregnancy included 18 patients with gestational hypertension, nine with mild preeclampsia and 16 with severe preeclampsia. MMP-1 and TIMP-1 ELISA kits were used to determine the MMP-1 and TIMP-1 levels in the umbilical serum of the parturient following delivery. MMP-1 and TIMP-1 expressed in the placenta and decidua of the parturient following delivery were evaluated using immunohistochemistry. MMP-1 and TIMP-1 were mainly located in cytotrophoblasts and syncytiotrophoblasts in the placenta and decidua. The levels of MMP-1 in the umbilical serum of the normal, gestational hypertension, mild preeclampsia and severe preeclampsia groups were 294.33±11.53, 247.78±20.32, 177.67±12.63 and 124.68±15.41 pg/ml, respectively, and there were significant differences between each two groups (P<0.05). The positive expression rate of MMP-1 in the placenta and decidua of patients with hypertensive disorders in pregnancy was lower than that of the controls (P<0.01 and P<0.01, respectively). However, no significant difference was identified between each two groups with regard to the levels of TIMP-1 in the umbilical cord and the positive rates in the placenta and decidua (P>0.05). Reduced MMP-1 levels in the umbilical serum, placenta and decidua were observed in women who developed preeclampsia.

[Effects of ZnO Nanoparticles, ZnSO4 and Arbuscular Mycorrhizal Fungus on the Growth of Maize].

As one of the most widely used metal-based nanoparticles (NPs), ZnO NPs have been shown to be toxic to organisms. Arbuscular mycorrhizal (AM) fungi can improve mineral nutrition and increase the resistance of host plants. However, little is known on the interaction between ZnO NPs and other Zn pollutants, as well as the effect of AM fungi on their biological effects. The present greenhouse pot culture experiment studied the effects of inoculation with or without AM fungus Funneliformis mosseae BEG 167 on the growth of maize in soil supplemented with ZnO NPs and ZnSO4 (500 mg · kg⁻¹) seperately or in combination. The results showed that ZnO NPs inhibited mycorrhizal colonization and the growth of maize plants, showing similar phytotoxicity and effects to ZnSO4at the same concentration (500 mg · kg⁻¹). Compared with the nonmycorrhizal controls, AM fungal inoculation decreased Zn concentrations or uptake in maize plants, and showed a better growth-promoting effect in the combination treatment. Our results showed for the first time that there was a complex interaction in their biological toxicity between ZnO NPs and ZnSO4, while AM fungal inoculation exhibited a protective effect under combined pollution of ZnO NPs and ZnSO4.

[Genetic diagnosis of fructose-1, 6-bisphosphatase deficiency: a case report].

OBJECTIVE: To report the first case of fructose-1,6-bisphosphatase (FBPase) deficiency diagnosed by genetic sequencing in China, and to improve the cognition of this rare disease. METHODS: The clinical and laboratory characteristics of FBPase deficiency were reviewed, and the findings of direct sequencing of genomic DNA described, and published literature on FBPase deficiency reviewed. RESULTS: A 23-month-old boy was repeatedly admitted for 5 times with recurrent onset of lethargy and drowsiness every time after diarrhea and vomiting for 2-3 days during the last 7 months after being weaned, and he had convulsion this time. On admission, his physical examination showed tachypnea, and mild hepatomegaly, and he had normal physical and mental development. His paternal-grandparents had cousinship, and his parents were collateral relatives in the fifth generation. The laboratory findings revealed severe hypoglycemia, lacticacidemia, metabolic acidosis, ketonemia and hyperuricacidemia. After intravenous infusion of glucose, bicarbonate and antibiotics, there was a dramatic clinical improvement in a short time. Urine organic acids analyses ever showed an elevation of gluconeogenetic substrates including lactic acid, ketone and glycerol. The molecular analysis of liver fructose-1, 6-bisphosphatase (FBP1) gene showed a homozygous mutation with one G residue insertion at base 961 in exon 7(c.960/961insG), resulting in a reading frame shift mutation of 320th amino acid and premature termination at 333th amino acid. This mutation had been reported to be the most common mutation among patients with FBPase deficiency. Frequent feeding by avoiding taking in too much sweet food, restriction of food with high protein and fat, and the use of uncooked starch had been taken after our patient was discharged from the hospital. There had been no attack in the last 9 months. CONCLUSION: Clinicians must consider the diagnosis of FBPase deficiency when confronted with the patient who has episodes of severe hypoglycemia and lacticacidemia, especially accompanied by metabolic acidosis and ketonemia, which are typically triggered by infection and fasting. Early diagnosis, urgent treatment of hypoglycemia and appropriate diet control can prevent death, improve growth and quality of life of these children.

[Arbuscular mycorrhizal symbiosis influences the biological effects of nano-ZnO on maize].

Engineered nanoparticles (ENPs) can be taken up and accumulated in plants, then enter human bodies via food chain, and thus cause potential health risk. Arbuscular mycorrhizal fungi form mutualistic symbioses with the majority of higher plants in terrestrial ecosystems, and potentially influence the biological effects of ENPs. The present greenhouse pot culture experiment studied the effects of inoculation with or without arbuscular mycorrhizal fungus Acaulospora mellea on growth and nutritional status of maize under different nano-ZnO levels (0, 500, 1 000, 2000 and 3 000 mg x kg(-1)) artificially added into soil. Results showed that with the increasing nano-ZnO levels in soil, mycorrhizal colonization rate and biomass of maize plants showed a decreasing trend, total root length, total surface area and total volume reduced, while Zn concentration and uptake in plants gradually increased, and P, N, K, Fe, and Cu uptake in shoots all decreased. Compared with the controls, arbuscular mycorrhizal inoculation improved the growth and P, N and K nutrition of maize, enhanced total root length, total surface area and total volume, and increased Zn allocation to roots when nano-ZnO was added. Our results firstly show that nano-ZnO in soil induces toxicity to arbuscular mycorrhizae, while arbuscular mycorrhizal inoculation can alleviate its toxicity and play a protective role in plants.

[Value of muscle enzyme analysis in differential diagnosis of childhood myopathic hyper-creatine kinase-emia].

OBJECTIVE: To summarize the etiology and clinical characteristics of children with myopathic elevated creatine kinase (CK) levels. The degrees of elevated CK as well as lactic dehydrogenase (LDH) and aspartate aminotransferase (AST) levels in different myopathy were analyzed. METHODS: The clinical data of 235 cases characterized as myopathic hyper-CK-emia from January 2004 to December 2011 were collected and analyzed. A retrospective analysis of LDH and AST levels according to CK in part of the patients were reviewed. RESULTS: Of the 235 cases, 180 were male and 55 female. According to the age at which hyper-CK-emia was diagnosed, 64 cases were under 6 months, 90 between 6 months and 3 years, 50 between 3 and 6 years and 31 between 6 and 14 years. Their CK levels significantly increased in 162 cases, moderately increased in 31 cases, and slightly increased in 42 cases. The age at which hyper-CK-emia was diagnosed and the CK level had no correlation with muscle weakness and the severity. As to CK levels: Duchenne muscular dystrophy (DMD) > inflammatory myopathies > congenital muscular dystrophy (CMD) > metabolic myopathies. LDH and AST levels: DMD > inflammatory myopathies > metabolic myopathies > CMD. CONCLUSION: Unlike adults, the etiology of myopathic hyper-CK-emia in children is complicated and diverse. The onset type, the degree and duration of hyper-CK-emia are helpful to make the diagnosis. CK increases most significantly in DMD, then in inflammatory myopathies, CMD, and metabolic myopathies. Diagnostic flowchart of myogenic hyper-CK-emia should follow a certain process, and the indications of biochemical tests, metabolic screening, electrophysiological examination, muscle biopsy and genetic testing should be made. Finally, different treatments should be designed according to the etiology.

Ameliorating replicative senescence of human bone marrow stromal cells by PSMB5 overexpression.

Multipotent human bone marrow stromal cells (hBMSCs) potentially serve as a source for cell-based therapy in regenerative medicine. However, in vitro expansion was inescapably accompanied with cell senescence, characterized by inhibited proliferation and compromised pluripotency. We have previously demonstrated that this aging process is closely associated with reduced 20S proteasomal activity, with down-regulation of rate-limiting catalytic ß-subunits particularly evident. In the present study, we confirmed that proteasomal activity directly contributes to senescence of hBMSCs, which could be reversed by overexpression of the ß5-subunit (PSMB5). Knocking down PSMB5 led to decreased proteasomal activity concurrent with reduced cell proliferation in early-stage hBMSCs, which is similar to the senescent phenotype observed in late-stage cells. In contrast, overexpressing PSMB5 in late-stage cells efficiently restored the normal activity of 20S proteasomes and promoted cell growth, possibly via upregulating the Cyclin D1/CDK4 complex. Additionally, PSMB5 could enhance cell resistance to oxidative stress, as evidenced by the increased cell survival upon exposing senescent hBMSCs to hydrogen peroxide. Furthermore, PSMB5 overexpression retained the pluripotency of late-stage hBMSCs by facilitating their neural differentiation both in vitro and in vivo. Collectively, our work reveals a critical role of PSMB5 in 20S proteasome-mediated protection against replicative senescence, pointing to a possible strategy for maintaining the integrity of culture-expanded hBMSCs by manipulating the expression of PSMB5.

Melanoma differentiation-associated gene 5 in zebrafish provoking higher interferon-promoter activity through signalling enhancing of its shorter splicing variant.

Melanoma differentiation-associated gene 5 (MDA5) is one of the three members in the retinoic acid-inducible gene I-like receptor (RLR) family, which are cytoplasmic pathogen recognition receptors recognizing intracellular viruses. In the present study, MDA5 and its spliced shorter forms, named as MDA5a and MDA5b, were identified in zebrafish. MDA5a and MDA5b can be up-regulated in cell lines following the infection of a negative ssRNA virus, the spring viraemia of carp virus (SVCV), and an intracellular Gram-negative bacterial pathogen Edwardsiella tarda, implying that the RLR may also be able to sense elements released from bacteria. The over-expression of MDA5a and MDA5b in fish cells resulted in significant induction of type I interferon promoter activity and enabled the protection of transfected cells against SVCV infection. Furthermore, the shorter spliced form, MDA5b when co-transfected with MDA5a or mitochondrial antiviral signalling protein (MAVS), induced a significantly higher level of interferon promoter activity, indicating that MDA5b may function as an enhancer in the interaction between MDA5 and MAVS.

Potential role of 20S proteasome in maintaining stem cell integrity of human bone marrow stromal cells in prolonged culture expansion.

Human bone marrow stromal cells (hBMSCs) could be used in clinics as precursors of multiple cell lineages following proper induction. Such application is impeded by their characteristically short lifespan, together with the increasing loss of proliferation capability and progressive reduction of differentiation potential after the prolonged culture expansion. In the current study, we addressed the possible role of 20S proteasomes in this process. Consistent with prior reports, long-term in vitro expansion of hBMSCs decreased cell proliferation and increased replicative senescence, accompanied by reduced activity and expression of the catalytic subunits PSMB5 and PSMB1, and the 20S proteasome overall. Application of the proteasome inhibitor MG132 produced a senescence-like phenotype in early passages, whereas treating late-passage cells with 18α-glycyrrhetinic acid (18α-GA), an agonist of 20S proteasomes, delayed the senescence progress, enhancing the proliferation and recovering the capability of differentiation. The data demonstrate that activation of 20S proteasomes assists in counteracting replicative senescence of hBMSCs expanded in vitro.