SIRT1 activated by AROS sensitizes glioma cells to ferroptosis via induction of NAD+ depletion-dependent activation of ATF3.

Ferroptosis is a type of programmed cell death resulting from iron overload-dependent lipid peroxidation, and could be promoted by activating transcription factor 3 (ATF3). SIRT1 is an enzyme accounting for removing acetylated lysine residues from target proteins by consuming NAD+, but its role remains elusive in ferroptosis and activating ATF3. In this study, we found SIRT1 was activated during the process of RSL3-induced glioma cell ferroptosis. Moreover, the glioma cell death was aggravated by SIRT1 activator SRT2183, but suppressed by SIRT inhibitor EX527 or when SIRT1 was silenced with siRNA. These indicated SIRT1 sensitized glioma cells to ferroptosis. Furthermore, we found SIRT1 promoted RSL3-induced expressional upregulation and nuclear translocation of ATF3. Silence of ATF3 with siRNA attenuated RSL3-induced increases of ferrous iron and lipid peroxidation, downregulation of SLC7A11 and GPX4 and depletion of cysteine and GSH. Thus, SIRT1 promoted glioma cell ferroptosis by inducting ATF3 activation. Mechanistically, ATF3 activation was reinforced when RSL3-induced decline of NAD+ was aggravated by FK866 that could inhibit NAD + synthesis via salvage pathway, but suppressed when intracellular NAD+ was maintained at higher level by supplement of exogenous NAD+. Notably, the NAD + decline caused by RSL3 was enhanced when SIRT1 was further activated by SRT2183, but attenuated when SIRT1 activation was inhibited by EX527. These indicated SIRT1 promoted ATF3 activation via consumption of NAD+. Finally, we found RSL3 activated SIRT1 by inducing reactive oxygen species-dependent upregulation of AROS. Together, our study revealed SIRT1 activated by AROS sensitizes glioma cells to ferroptosis via activation of ATF3-dependent inhibition of SLC7A11 and GPX4.

RIP1 and RIP3 contribute to shikonin-induced glycolysis suppression in glioma cells via increase of intracellular hydrogen peroxide.

RIP1 and RIP3 are necroptosis initiators, but their roles in regulation of glycolysis remain elusive. In this study, we found shikonin activated RIP1 and RIP3 in glioma cells in vitro and in vivo, which was accompanied with glycolysis suppression. Further investigation revealed that shikonin-induced decreases of glucose-6-phosphate and pyruvate and downregulation of HK II and PKM2 were significantly prevented when RIP1 or RIP3 was pharmacologically inhibited or genetically knocked down with SiRNA. Moreover, shikonin also triggered accumulation of intracellular H2O2 and depletion of GSH and cysteine. Mitigation of intracellular H2O2 via supplement of GSH reversed shikonin-induced glycolysis suppression. The role of intracellular H2O2 in regulation of glycolysis suppression was further confirmed in the cells treated with exogenous H2O2. Notably, inhibition of RIP1 or RIP3 prevented intracellular H2O2 accumulation, which was correlated with preventing shikonin-induced downregulation of x-CT and depletion of GSH and cysteine. In addition, supplement of pyruvate effectively inhibited shikonin- or exogenous H2O2-induced accumulation of intracellular H2O2 and glioma cell death. Taken together, we demonstrated in this study that RIP1 and RIP3 contributed to shikonin-induced glycolysis suppression via increasing intracellular H2O2.

Pseudolaric acid B triggers ferroptosis in glioma cells via activation of Nox4 and inhibition of xCT.

Ferroptosis is a form of programmed cell death decided by iron-dependent lipid peroxidation, but its role in glioma cell death remains unclear. In this study, we found Pseudolaric acid B (PAB) inhibited the viabilities of glioma cells in vitro and in vivo, which was accompanied by abnormal increases of intracellular ferrous iron, H2O2 and lipid peroxidation, as well as depletion of GSH and cysteine. In vitro studies revealed that the lipid peroxidation and the cell death caused by PAB were both inhibited by iron chelator deferoxamine, but exacerbated by supplement of ferric ammonium citrate. Inhibition of lipid peroxidation with ferrostatin-1 or GSH rescued PAB-induced cell death. Morphologically, the cells treated with PAB presented intact membrane, shrunken mitochondria with increased membrane density, and normal-sized nucleus without chromatin condensation. Mechanistically, PAB improved intracellular iron by upregulation of transferrin receptor. The increased iron activated Nox4, which resulted in overproduction of H2O2 and lipid peroxides. Moreover, PAB depleted intracellular GSH via p53-mediated xCT pathway, which further exacerbated accumulation of H2O2 and lipid peroxides. Thus, PAB triggers ferroptosis in glioma cells and is a potential medicine for glioma treatment.

The comparison of teaching efficiency between massive open online courses and traditional courses in medicine education: a systematic review and meta-analysis.

BACKGROUND: This systematic review and meta-analysis aimed to investigate and compare the passing rates of Massive Open Online Courses (MOOCs) with Traditional Courses to indicate how to improve the teaching efficiency in Medicine Education. METHODS: A systematic search of relevant published literature was conducted to collect relevant retrospective cohort studies that compared the teaching efficiency of MOOCs and Traditional Courses. RESULTS: There are three retrospective cohort studies included in the final meta-analysis. There were no significant differences in the passing rates of MOOCs and Traditional Courses. CONCLUSIONS: it is necessary for universities to invest in online education to promote the development of MOOCs, which will probably have an advantage over Traditional Courses for postgraduate medical education in the near future.

Deoxypodophyllotoxin triggers parthanatos in glioma cells via induction of excessive ROS.

Parthanatos is a new form of programmed cell death that is regulated by hyper-activated PARP-1, and is emerging as a new strategy to kill cancer cells. Deoxypodophyllotoxin (DPT) is a natural chemical that is found to induce cancer cell death, in which the role of parthanatos is unknown. Thus, we investigated this issue in this study by using glioma cell lines and mice model of xenograft glioma. We found that DPT induced glioma cell death in vitro and inhibited the growth of xenograft glioma in vivo, which was accompanied with parthanatos-related biochemical events including expressional upregulation of PARP-1, cytoplasmic accumulation of PAR polymer, and nuclear translocation of AIF. In vitro study revealed that genetic knockdown of PARP-1 with small interfering RNA attenuated DPT-induced elevation in the cytoplasmic PAR-polymer and the nuclear AIF, as well as protected glioma cells against the toxicity of DPT. Further, antioxidant NAC, as well as PARP-1 inhibitor 3AB, not only alleviated the overproduction of ROS caused by DPT, but also reversed the above-mentioned biochemical events, maintained mitochondrial membrane potential and rescued glioma cells death. Therefore, we demonstrated that deoxypodophyllotoxin triggered parthanatos in glioma cells via induction of excessive ROS.

Inhibition of autophagy via activation of PI3K/Akt pathway contributes to the protection of ginsenoside Rb1 against neuronal death caused by ischemic insults.

Lethal autophagy is a pathway leading to neuronal death caused by transient global ischemia. In this study, we examined the effect of Ginsenoside Rb1 (GRb1) on ischemia/reperfusion-induced autophagic neuronal death and investigated the role of PI3K/Akt. Ischemic neuronal death in vitro was induced by using oxygen glucose deprivation (OGD) in SH-SY5Y cells, and transient global ischemia was produced by using two vessels occlusion in rats. Cellular viability of SH-SY5Y cells was assessed by MTT assay, and CA1 neuronal death was evaluated by Hematoxylin-eosin staining. Autophagic vacuoles were detected by using both fluorescent microscopy in combination with acridine orange (AO) and Monodansylcadaverine (MDC) staining and transmission electronic microscopy. Protein levels of LC3II, Beclin1, total Akt and phosphor-Akt at Ser473 were examined by western blotting analysis. GRb1 inhibited both OGD and transient ischemia-induced neuronal death and mitigated OGD-induced autophagic vacuoles in SH-SY5Y cells. By contrast, PI3K inhibitor LY294002 counteracted the protection of GRb1 against neuronal death caused by either OGD or transient ischemia. LY294002 not only mitigated the up-regulated protein level of phosphor Akt at Ser473 caused by GRb1, but also reversed the inhibitory effect of GRb1 on OGD and transient ischemia-induced elevation in protein levels of LC3II and Beclin1.

Growth and anaemia among infants and young children for two years after the Wenchuan earthquake.

BACKGROUND: In order to monitor malnutrition morbidity and anaemic prevalence of infants and young children in rural disaster areas affected by Wenchuan earthquake. METHODS: About three months, one year and two years after earthquake (including 77, 102 and 307 children, respectively), by using the questionnaires, information on nutritional and health status of infants and young children aged 6-23 months was collected and evaluated, and anthropometry and haemoglobin concentration were measured. RESULTS: Most of families could not prepare complementary foods for their children so that the children only ate the same meals as adults which resulted in very poor situation in the quantity and quality of complementary food for infants and young children. The main nutritional problems in children included the lack of feeding knowledge in parents; only 10% children could have breast feeding within one hour after delivery, and the basic exclusive breastfeeding was lower. More than 90% children never received nutrient supplements. The malnutrition prevalence was significantly increased two years after the earthquake. The decrease of body weight was rapid (underweight prevalence from 0 at three months to 5.9% after two years), and then a lasting effect resulted in decrease of length shown by stunting prevalence from 6.6% at three months to 10.8% after two years and wasting prevalence from 1.3% at three months to 4.0% after two years. From three months to two years after earthquake, anaemic prevalence markedly increased from 36.5% to 67.5% and the increasing percentage of anaemia was more obvious in girls than boys. CONCLUSION: The child's nutritional status continuously worsened and anaemic prevalence was high in areas affected by the earthquake. It is recommended that in the future nutrition interventions should begin immediately.

[Changes of iodine nutrition status and thyroid function among pregnant women in iodine sufficient rural area of Gansu province].

OBJECTIVE: To assess the iodine nutrition and thyroid function of pregnant women during different periods of pregnancy, to provide evidence for guiding iodine supplementation for them. METHODS: A cross-sectional survey was performed in 215 pregnant women in Yongjing couty from May to June 2013. Samples of blood and random urine were collected, and serum thyrotrophin (TSH), free triiodothyronine (FT3), free thyroxine (FT4), anti-thyroid peroxidase (anti-TPO), antithyroglobulin ( anti-TG)and urinary iodine were measured. RESULTS: The medians of urinary iodine from the three groups of pregnant women(first, second and third trimester) were 189.8 µg/L, 152.5 µg/L and 144.9 µg/L respectively. With the exception of pregnant women in the third trimester, the urinary iodine medians of pregnant women in the first and second trimesters were within the 150-249 µg/L range which was defined as optimal by WHO/UNICEF/ICCIDD. With the increase of gestational age, the level of FT3 decreased (P < 0.05), with the FT3 levels in the first trimester were higher than those in the second or third trimester (P < 0.05). The difference of TSH levels among the three groups of pregnant women was statistically significant (P < 0.01), with a U-shaped curve seen between the iodine TSH levels and the gestational age. The medians of anti-TG and anti-TPO appeared the lowest in the first trimester, and remained at a high level in women at second and third trimesters. Significant difference was seen in anti-TG, anti-TPO levels of the three groups of pregnant women (first, second and third trimester) (P < 0.01). The incidence of thyroid function disorder was 1.86%, including subclinical hypothyroidism accounted for 1.40%, and hypothyroidism accounted for 0.47%. The incidence of thyroid function disorder mainly appeared in the early pregnancy. Abnormal FT3, TSH, positive anti-TG and anti-TPO were mainly seen during early pregnancy. The changes of TSH, FT3, FT4, anti-TG and anti-TPO along with the changes of urine iodine levels were not obvious. CONCLUSION: With the increase of gestational age, the incidence of iodine deficiency also increased among pregnant women. Abnormal thyroid hormones, TSH, positive anti-TG and anti-TPO were mainly existed in the early pregnancy. Programs as monitoring urinary iodine as well as thyroid function targeting all the pregnant women should be carried out.

Ginsenoside Rb1 attenuates oxygen-glucose deprivation-induced apoptosis in SH-SY5Y cells via protection of mitochondria and inhibition of AIF and cytochrome c release.

To investigate the role of mitochondria in the protective effects of ginsenoside Rb1 on cellular apoptosis caused by oxygen-glucose deprivation, in this study, MTT assay, TUNEL staining, flow cytometry, immunocytochemistry and western blotting were used to examine the cellular viability, apoptosis, ROS level, mitochondrial membrane potential, and the distribution of apoptosis inducing factor, cytochrome c, Bax and Bcl-2 in nucleus, mitochondria and cytoplasm. We found that pretreatment with GRb1 improved the cellular viability damaged by OGD. Moreover, GRb1 inhibited apoptosis in SH-SY5Y cells induced by OGD. Further studies showed that the elevation of cellular reactive oxygen species levels and the reduction of mitochondrial membrane potential caused by OGD were both counteracted by GRb1. Additionally, GRb1 not only suppressed the translocation of apoptosis inducing factor into nucleus and cytochrome c into cytoplasm, but also inhibited the increase of Bax within mitochondria and alleviated the decrease of mitochondrial Bcl-2. Our study indicates that the protection of GRb1 on OGD-induced apoptosis in SH-SY5Y cells is associated with its protection on mitochondrial function and inhibition of release of AIF and cytochrome c.

Prospective study on the effectiveness of complementary food supplements on improving status of elder infants and young children in the areas affected by Wenchuan earthquake.

OBJECTIVE: To prospectively evaluate the efficiency of daily providing complementary food supplements decreasing malnutrition and anemia prevalence in elder infants and young children living in areas affected by Wenchuan Earthquake. DESIGN: Using promotional probability sampling method, 250 to 300 children from six-randomized townships (30 to 50 children in each township) in Kang County affected by the Earthquake were randomly chosen for follow up to evaluate intervention effectiveness using anthropometric measurement and hemoglobin level at six, twelve and eighteen months after start of intervention. SETTING AND SUBJECTS: All children from 6 to 18 months of age in Kang County (in North Western China) were daily provided with complementary food supplements containing multiple vitamins and minerals for up to 24 months of age. The intervention period lasted for one and half year. RESULTS: At beginning of intervention, malnutrition prevalence, including underweight, stunting and wasting were respectively 4.5%, 8.9% and 3.5%; anemia prevalence was 74.3%. After one and half year intervention, the growth and anemia status were significantly improved; the percentages of wasting, stunting underweight prevalence were decreased from 3.5%, 8.9% and 4.5% to 1.7%, 5.0% and 3.3% respectively, and the anemia rates were significantly decreased. CONCLUSIONS: Our results indicated that an intervention using complementary food supplements could improve nutritional status and elevate hemoglobin level in elder infants and young children, which would significantly decrease the prevalence of malnutrition and anemia.

Shikonin kills glioma cells through necroptosis mediated by RIP-1.

BACKGROUND AND PURPOSE: Shikonin was reported to induce necroptosis in leukemia cells, but apoptosis in glioma cell lines. Thus, it is needed to clarify whether shikonin could cause necroptosis in glioma cells and investigate its underlying mechanisms. METHODS: Shikonin and rat C6 glioma cell line and Human U87 glioma cell line were used in this study. The cellular viability was assayed by MTT. Flow cytometry with annexin V-FITC and PI double staining was used to analyze cellular death modes. Morphological alterations in C6 glioma cells treated with shikoinin were evaluated by electronic transmission microscopy and fluorescence microscopy with Hoechst 33342 and PI double staining. The level of reactive oxygen species was assessed by using redox-sensitive dye DCFH-DA. The expressional level of necroptosis associated protein RIP-1 was analyzed by western blotting. RESULTS: Shikonin induced cell death in C6 and U87 glioma cells in a dose and time dependent manner. The cell death in C6 and U87 glioma cells could be inhibited by necroptosis inhibitor necrotatin-1, not by pan-caspase inhibitor z-VAD-fmk. Shikonin treated C6 glioma cells presented electron-lucent cytoplasm, loss of plasma membrane integrity and intact nuclear membrane in morphology. The increased ROS level caused by shikonin was attenuated by necrostatin-1 and blocking ROS by anti-oxidant NAC rescued shikonin-induced cell death in both C6 and U87 glioma cells. Moreover, the expressional level of RIP-1 was up-regulated by shikonin in a dose and time dependent manner as well, but NAC suppressed RIP-1 expression. CONCLUSIONS: We demonstrated that the cell death caused by shikonin in C6 and U87 glioma cells was mainly via necroptosis. Moreover, not only RIP-1 pathway, but also oxidative stress participated in the activation of shikonin induced necroptosis.

Iodine deficiency disorders after a decade of universal salt iodization in a severe iodine deficiency region in China.

BACKGROUND & OBJECTIVE: Universal salt iodization (USI) was implemented in all counties of China in 1995. This study was undertaken to assess the status of iodine deficiency disorders control and prevention after 10 years of implementation of USI in a severe iodine deficiency region in China. METHODS: Thirty primary school were selected in Gansu province utilizing cluster sampling methodology for the years 1995 and 2005. In each selected school, 40 children aged 8-10 yr were randomly selected for thyroid and IQ examination, and urinary samples were collected from 12. On the spot casual urine samples and salt samples were collected from a subset of children included in the study. In 2005, casual urine samples were also collected from 50 pregnant and lactating women in each cluster. Effect of health education was studied by a combination method of giving questionnaires to and observing students and families. RESULTS: The total goiter rates (TGR) were found to be 13.5 and 38.7 per cent in 2005 and 1995 respectively. The medians urinary iodine excretion levels of children were 191.8 and 119.9 mICROg/l in 2005 and 1995. The median urinary iodine excretion level of women was 161.9 mICROg/l. The mean intelligence quotient (IQ) was 96.9 in 2005 significantly more than that in 1997 (P<0.05). The health education pass rate of children and women were 21.1 and 51.1 per cent respectively. INTERPRETATION & CONCLUSION: After ten years of universal salt iodization (USI), iodine nutrition of people improved and the current iodine nutrition status of population was adequate. Decrease in TGR and increase in IQ showed that IDD control and prevention had made great progress through ten years USI, salt iodization played the key role in IDD control and prevention for sustained elimination of IDD, the programme of USI and other measures like health education should be persisted and enforced.

Iodine status and thyroid function of pregnant, lactating women and infants (0-1 yr) residing in areas with an effective Universal Salt Iodization program.

OBJECTIVE: To assess the iodine nutrition and thyroid function of pregnant women, lactating women and infants residing in areas where the Universal Salt Iodization program is in place. METHODS: Pregnant women, lactating women and infants were selected randomly in the regions where iodized salt coverage rate is more than 90% since 2000. Urine iodine levels of pregnant woman, lactating woman and infants, milk iodine of lactating woman, thyroid-stimulating hormone (TSH) and free T4 of women were tested respectively. RESULTS: Median Urinary Iodine (MUI) of infants, three groups of pregnant women (first, second and third trimester) and two groups lactating women (breastfeeding less than or more than six months) were 233, 174, 180, 147, 126 and 145 microg/L, respectively. Median milk iodine of lactating women was 163 microg/L. Percentage of milk iodine < 150 microg/L of early lactating women was 40% less than that of late lactating women (p < 0.01).There was a positive correlation between urine iodine of infants and milk iodine of lactating women (r = 0.526, p = 0.000). T4 of two women were above or below the reference range. Total 15.4% women's TSH were abnormal. Most of these women's urinary iodine were lower than 150 microg/L. CONCLUSION: Iodine status of most of the target population for Universal Salt Iodization program is adequate, but iodine deficiency still existed in some. To assure every new life's brain not be damaged by iodine deficiency, iodine status of targeted populations should be monitored and supplements provided according to the monitoring outcomes.