LncRNA-Malat1 is Involved in Lipotoxicity-Induced ß-cell Dysfunction and the Therapeutic Effect of Exendin-4 via Ptbp1.

Increasing evidence indicates that long noncoding RNAs (lncRNAs) have crucial roles in various biological processes. However, the contribution of lncRNAs to ß-cell dysfunction and their roles in diabetes therapeutics remain poorly understood. The aim of this study was to identify the lncRNAs dysregulated in diabetic islets and to explore the lncRNAs involved in ß-cell function as potential therapeutic targets. By using RNA sequencing and real-time PCR, we identified thousands of lncRNAs in the islets of db/db mice and db/m littermate mice. Among the differentially expressed lncRNAs, lncRNA-Malat1 (metastasis-associated lung adenocarcinoma transcript 1) was reduced in the islets of db/db mice and palmitate-treated MIN6 cells. The results of TUNEL, Western blot and flow cytometric analyses, and GSIS assays revealed that Malat1 knockdown significantly induced ß-cell apoptosis and inhibited insulin secretion. Mechanistically, RNA immunoprecipitation showed that Malat1 enhanced polypyrimidine tract-binding protein 1 (Ptbp1) protein stability by direct interaction, thereby adjusting the ratio of pyruvate kinase muscle (PKM) isoforms 1 and 2 (PKM1/PKM2). Moreover, luciferase assay and chromatin immunoprecipitation indicated that Malat1 was transcriptionally activated by pancreatic and duodenal homeobox 1 (Pdx1), through which exendin-4 alleviated lipotoxicity-induced ß-cell damage. In summary, our findings suggested the involvement of Malat1 in ß-cell dysfunction under diabetic conditions via the Malat1/Ptbp1/PKM2 pathway. In addition, exendin-4 ameliorated ß-cell impairment by Pdx1-mediated Malat1 upregulation. Hence, Malat1 may serve as a therapeutic target for the treatment of type 2 diabetes.

Effect of elevation of vascular endothelial growth factor level on exacerbation of hemorrhage in mouse brain arteriovenous malformation.

OBJECTIVE: A high level of vascular endothelial growth factor (VEGF) has been implicated in brain arteriovenous malformation (bAVM) bleeding and rupture. However, direct evidence is missing. In this study the authors used a mouse bAVM model to test the hypothesis that elevation of focal VEGF levels in bAVMs exacerbates the severity of bAVM hemorrhage. METHODS: Brain AVMs were induced in adult mice in which activin receptor-like kinase 1 (Alk1, a gene that causes AVM) gene exons 4-6 were floxed by intrabasal ganglia injection of an adenoviral vector expressing Cre recombinase to induce Alk1 mutation and an adeno-associated viral vector expressing human VEGF (AAV-VEGF) to induce angiogenesis. Two doses of AAV-VEGF (5 × 109 [high] or 2 × 109 [low]) viral genomes were used. In addition, the common carotid artery and external jugular vein were anastomosed in a group of mice treated with low-dose AAV-VEGF 6 weeks after the model induction to induce cerebral venous hypertension (VH), because VH increases the VEGF level in the brain. Brain samples were collected 8 weeks after the model induction. Hemorrhages in the bAVM lesions were quantified on brain sections stained with Prussian blue, which detects iron deposition. VEGF levels were quantified in bAVM tissue by enzyme-linked immunosorbent assay. RESULTS: Compared to mice injected with a low dose of AAV-VEGF, the mice injected with a high dose had higher levels of VEGF (p = 0.003) and larger Prussian blue-positive areas in the bAVM lesion at 8 or 9 weeks after model induction (p = 0.002). VH increased bAVM hemorrhage in the low-dose AAV-VEGF group. The overall mortality in the high-dose AAV-VEGF group was 26.7%, whereas no mouse died in the low-dose AAV-VEGF group without VH. In contrast, VH caused a mortality of 50% in the low-dose AAV-VEGF group. CONCLUSIONS: Using mouse bAVM models, the authors provided direct evidence that elevation of the VEGF level increases bAVM hemorrhage and mouse mortality.

[Status of lactating women's iodine nutrition and thyroid function in different iodine nutrition level of children in Gansu Province].

OBJECTIVE: To assess the iodine nutrition and thyroid function of lactatingwomen in different iodine nutrition level of children in Gansu Province, and provide a scientific basis for iodine supplementation. METHODS: Liangzhou district( the median urinary iodine was greater than or equal to 300 g/L), Linze county( the median urinary iodine was from 200 to 299 g/L) and Huating county( the median urinary iodine was from100 to 199 g/L) were selected according to 8-10 years old children urinary iodine in2009. Huating county, Liangzhou district and Linze county were as iodine excessive area, iodine suitable area 1 and iodine suitable area 2, respectively in 2014. One township was randomly selected from the east, west, south, north and middle parts of each research point, 10 lactating women were randomly collected in each township, who was tested urine samples and thyroid function. Salt intake was surveyed in 3 townships. 2 samples were collected in centralized water supplies, 1 sample was collected in its coverage by the east, west, south, north and middle parts; 1 sample was collected by the east, west, south, north and middle parts in decentralized water supplies, which were tested of water iodine. RESULTS: The medians of water iodine were 2. 32, 0. 70 and 6. 18 µg/L and the medians of salt iodine were 25. 3, 25. 0 and 28. 6 mg/kg for iodine excessive area, iodine suitable area 1 and iodine suitable area 2, respectively. Per capita daily intake of salt were 15. 0, 11. 3 and 4. 7 g for iodine excessive area, iodine suitable area 1 and iodine suitable area 2 respectively, there were statisticant differences. The median urinary iodine of lactating women were 181. 8, 143. 1 and 104. 9 µg/L for iodine excessive area, iodine suitable area 1 and iodine suitable area 2, respectively. The medians of thyroidstimulating hormone( TSH) were 2. 3, 2. 2 and 1. 9 mIU/L, mean values of free thyroxine( FT4) were 15. 0, 13. 9 and 14. 6 pmol/L, mean values of free triidothyronine( FT3) were 5. 0, 4. 8 and 4. 6 pmol/L for iodine excessive area, iodine suitable area 1 and iodine suitable area 2 respectively, there were not statistically differences. The positive rate of thyromicrosomal antibody( Tm Ab) were 3. 6 %, 11. 3 % and 13. 2 % and the positive rate of thyroglobulin antibody( Tg Ab) were 3. 6 %, 11. 3 % and 11. 3 % for iodine excessive area, iodine suitable area 1 and iodine suitable area 2 respectively( P >0. 05). Prevalence of thyroid function disorders were 14. 3 %, 21. 0 % and 9. 4 % and prevalence of low-FT4 syndrome were 7. 1 %, 4. 8 % and 1. 9 %, prevalence of subclinical hypothyroidism were 3. 6 %, 11. 3 % and 3. 8 % for iodine excessive area, iodine suitable area 1 and iodine suitable area 2 respectively( P > 0. 05). CONCLUSION: Iodine nutrition level was appropriate for lactating women in 3 areas, but some lactating women were iodine deficiency or iodine excess. There were occurred thyroid function disorders in some lactating women in 3 areas. The lactating women's iodine nutrition and thyroid function should be monitored and the normal reference value of thyroid function on lactating women should be established also.

[A comparative study on iodine nutrition and thyroid function of different population in urban and rural areas of Wuwei, Gansu province].

OBJECTIVE: To understand the iodine nutrition and thyroid function of different population in urban and rural areas of Gansu province and provide evidence for iodine supplementation. METHODS: A cross-sectional survey was performed in urban and rural children, adults, pregnant women and breastfeeding women in Wuwei from April 2009 to January 2010. Urine and fasting blood samples were collected from the subjects. Urine iodine content was measured with arsenic cerium catalytic spectrophatometry. The thyroid-stimulating hormone (TSH) , free thyroid hormone (FT4) and three free triiodothyronine (FT3) were detected by using direct chemiluminescence immunoassy. Non parametric test was used to compare the urinary iodine and TSH group. t test was used to compare FT4, FT3. χ² test was used to compare the rate. RESULTS: The medians of urinary iodine level (µg/L) were 358.6, 189.0, 255.4 and 239.5 in urban children, adults, pregnant women and breastfeeding women and 387.6, 258.5, 172.8 and 215.3 in rural children, adults, pregnant women and breastfeeding women respectively. The median of urinary iodine of urban adults was significantly lower than that in rural adults (Z=-4.020, P=0.000) and the medians of urinary iodine level of urban pregnant women was higher than that in rural pregnant women (Z=1.424, P=0.035). The mean value of FT3 in rural pregnant women and breastfeeding women were higher than that in urban groups (t=-3.933, P=0.000; t=-2.259, P=0.026). The mean value of FT4 in urban adults was higher than that in rural adults (t=3.539, P=0.001). The positive rate of TGAb and TMAb in rural pregnant women and breastfeeding women were 43.6%, 56.4% and 33.3%, 35.6%, respectively, which were higher than those in urban groups. Subclinical hypothyroidism in all thyroid function disorders was common in all the groups. No statistical significant difference in all thyroid function disorders were found in different population. CONCLUSION: The iodine nutrition were in good status in both urban population and rural population, the children's iodine nutrition was surplus. Statistical differences existed in iodine nutrition status or thyroid hormone level between urban and rural adults, pregnant women and breastfeeding women.

[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.

[Analysis of iodine nutrition and thyroid function of adults in urban areas of Wuwei city Gansu province].

OBJECTIVE: To find out the iodine nutrition and thyroid function of adults in urban areas of Wuwei city Gansu province and to provide a basis for scientific iodine supplementation. METHODS: A cross-sectional survey was performed in 104 adults in Wuwei city form the April 2009 to January 2010. The morning blood samples and one urine samples selected randomly of different people were collected and three free triiodothyronine (FT3), free thyroid hormone (FT4), total triiodothyronine (TT3), total thyroxine (TT4), the thyroid-stimulating hormone (TSH), thyroglobulin antibodies (TGAb), thyroid microsomal antibodies (TMAb) in blood samples and iodine in urine samples were detected. RESULTS: The medians of urinary iodine were respectively 139.3 microg/L and 212.6 microg/L for male and female, female was significantly higher than male, there were statisticant differences (P < 0.05). TT3, TT4, FT4, FT3 and TSH's mean values were in the normal range, the abnormal ratio of TT3, TT4, FT3, FT4, TSH were respectively 1.9%, 1.0%, 3.8%, 1.9%, 16.3%. The positive rate of TGAb and TMAb in female were all higher than male, there were statisticant differences (P < 0.05). Subclinical hypothyroidism in all thyroid function disorders was most and accounted for 14.4% and female were all higher than male (P < 0.05). The survey were divided into iodine deficiency group, adequate iodine group, over adequate iodine group and iodine excess group for urinary iodine level. The abnormal ratio of TT3, TT4, FT3, FT4, TSH in four groups had no statistically differences, but the positive rate of TGAb and TMAb raised with increased urinary iodine level. Thyroid function disorders occurred in the other three groups except iodine deficiency group, and there were statisticant differences. CONCLUSION: Iodine nutrition level is appropriate for adults in urban areas, but the female was higher than male. Subclinical hypothyroidism in all thyroid function disorders was most, the positive rate of TGAb and TMAb raised with increased urinary iodine level, the risk of female suffered from thyroid disease was higher than male.

[Analysis on iodine nutritional status and thyroid function in pregnant women].

OBJECTIVE: To investigate the iodine nutritional status 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 90 pregnant women in Wuwei City from April 2009 to January 2010. The morning blood samples and random urine samples were collected, and the thyroid-stimulating hormone (TSH), free triiodothyronine (FT3), free thyroid hormone (FT4), thyroglobulin antibodies (TGAb), thyroid microsomal antibodies (TMAb) in blood samples and iodine in urine samples were detected. RESULTS: The medians of urinary iodine were 231.49, 158.25 and 328.35 microg/L for women in early, middle and late period of pregnancy, The ratio of urinary iodine below 150 microg/L were 39.29%, 45.16% and 25.81%, respectively. The FT3, FT4 levels in the first trimester were higher than those in the third trimester (P < 0.05) and TSH level was increased, but no significant difference (P > 0.05). The positive rate of TGAb and TMAb antibody of pregnant women in different period of time were not significantly different (P > 0.05). The incidence of thyroid function disorder was significantly different in different gestation periods. CONCLUSION: Generally, the iodine nutritional status of these pregnant women was appropriate, but there was a tendency towards hypothyroid in some women. Monitoring urinary iodine and thyroid function in pregnant women should be carried out regularly.

[Isolation and identification of Suavissimoside R1 from roots of Rubus parvifollus used for protecting dopaminergic neurons against MPP+ toxicity].

OBJECTIVE: Suavissimoside R1 was isolated and identified as an active ingredient from Roots of Rubus parvifollus L, which exhibited protective effect on dopaminergic neurons against MPP+ toxicity. METHODS: The protective effects of crude extracts were investigated after mice were treated with 1-methyl4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). According to the protective effects of crude extracts, suavissimoside R1, one kind of triterpenoid saponin, was separated. It was investigated that whether Suavissimoside R1 can protect DA neurons from toxicity induced by MPP+ in rat mesencephalic cultures. RESULTS: Suavissimoside R1 was isolated from Roots of Rubus parvifollus L. Moreover, Suavissimoside R1, in dose of 100 micromol/L, alleviated the death of DA neurons induced by MPP+ obviously. CONCLUSION: These results suggest that suavissimoside R1 possesses potent neuroprotective activity and can be developed to be a potential anti-Parkinson's disease drug worthy for further study.

Phosphatidylethanolamine-N-methyltransferase activity and dietary choline regulate liver-plasma lipid flux and essential fatty acid metabolism in mice.

Phosphatidylethanolamine-N-methyltransferase (PEMT) catalyzes the methylation of phosphatidylethanolamine to form phosphatidylcholine (PC) and represents one of the two major pathways for PC biosynthesis. Mice with a homozygous disruption of the PEMT gene are dependent on the 1,2-diacylglycerol cholinephosphotransferase (CDP-choline) pathway for the synthesis of PC and develop severe liver steatosis when fed a diet deficient in choline. The present study used quantitative lipid metabolite profiling to characterize lipid metabolism in PEMT-deficient mice fed diets containing varying concentrations of choline. Choline supplementation restored liver, but not plasma PC concentrations of PEMT-deficient mice to levels commensurate with control mice. Choline supplementation also restored plasma triglyceride concentrations to normal levels, but did not restore plasma cholesterol ester concentrations in the PEMT-deficient mice to those equal to control mice. PEMT-deficient mice also had substantially diminished concentrations of docosahexaenoic acid [22:6(n-3)] and arachidonic acid [20:4(n-6)] in plasma, independent of choline status. Thus, choline supplementation rescued some but not all of the phenotypes induced by the knockout. These findings indicate that PEMT activity functions beyond its recognized role as a compensatory pathway for PC biosynthesis and that, in contrast, PEMT activity is involved in many physiologic processes including the flux of lipid between liver and plasma and the delivery of essential fatty acids to blood and peripheral tissues via the liver-derived lipoproteins.

Phosphatidylethanolamine N-methyltransferase (PEMT) knockout mice have hepatic steatosis and abnormal hepatic choline metabolite concentrations despite ingesting a recommended dietary intake of choline.

Choline is an essential nutrient for humans and is derived from the diet as well as from de novo synthesis involving methylation of phosphatidylethanolamine catalysed by the enzyme phosphatidylethanolamine N -methyltransferase (PEMT). This is the only known pathway that produces new choline molecules. We used mice with a disrupted Pemt-2 gene (which encodes PEMT; Pemt (-/-)) that have previously been shown to possess no hepatic PEMT enzyme. Male, female and pregnant Pemt (-/-) and wild-type mice ( n =5-6 per diet group) were fed diets of different choline content (deficient, control, and supplemented). Livers were collected and analysed for choline metabolites, steatosis, and apoptotic [terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labelling (TUNEL)] positive cells. We found that, in livers of Pemt (-/-) mice fed any of the diets, there was hepatic steatosis and significantly higher occurrence of TUNEL positive cells compared with wild-type controls. In male, female and pregnant mice, liver phosphatidylcholine concentrations were significantly decreased in Pemt (-/-) choline deficient and in Pemt (-/-) choline control groups but returned to normal in Pemt (-/-) choline supplemented groups. Phosphocholine concentrations in liver were significantly diminished in knockout mice even when choline was supplemented to above dietary requirements. These results show that PEMT normally supplies a significant portion of the daily choline requirement in the mouse and, when this pathway is knocked out, mice are unable to attain normal concentrations of all choline metabolites even with a supplemental source of dietary choline.