Differential expression profile of miRNAs in amniotic fluid exosomes from fetuses with Down syndrome / 南方医科大学学报

OBJECTIVE@#To investigate the role of miRNAs in amniotic fluid exosomes in growth and development of fetuses with Down syndrome (DS).@*METHODS@#Amniotic fluid were collected from 20 fetuses with DS and 20 normal fetuses (control) to extract amniotic exosome miRNA. MicroRNA sequencing technique was used to identify the differentially expressed miRNAs between the two groups, for which gene ontology (GO) and pathway analysis was performed. Three differentially expressed miRNAs with the strongest correlation with DS phenotype were selected for qPCR verification. Dual luciferase reporter assay was used to verify the activity of let-7d-5p for targeted regulation of BACH1.@*RESULTS@#We identified 15 differentially expressed miRNAs in DS as compared with the control group, among which 7 miRNAs were up-regulated and 8 were down-regulated. Target gene prediction results showed that the differentially expressed miRNAs targeted 17 DS-related genes. GO analysis revealed that the main functions of the target genes involved protein binding, protein transport, ATP binding, transferase activity and synapses. Pathway analysis revealed that the functional pathways were closely related with the development of the nervous system. qPCR results showed that the expression levels of miR-140-3p and let-7d-5p were significantly lower in DS group than in the control group (P < 0.05), as was consistent with miRNA sequencing results; the expression level of miR-4512 was significantly higher in DS group than in control group (P < 0.05), which was contrary to miRNA sequencing results. The results of double luciferase reporter gene assay confirmed that let-7d-5p was capable of targeted regulation of BACH1 expression.@*CONCLUSION@#Let-7d-5p in amniotic fluid exosomes may promote oxidative stress events in the brain of fetuses with DS by regulating BACH1 expression.

Effect of SET7/9-mediated endoplasmic reticulum stress on arsenic-induced hepatocyte apoptosis / 中国病理生理杂志

AIM:To investigate the effect of SET7/9 (SET domain containing 7/9) -mediated endoplasmic reticulum stress (ERS) on protein kinase R-like endoplasmic reticulum kinase (PERK) signaling pathway, and to explore the mechanisms of arsenic-induced hepatocyte apoptosis.METHODS:Human liver LO2 cells were divided into control group, arsenic poisoning model group, negative transfection group and SET7/9 siRNA transfection group.The apoptosis of the LO2 cells in each group was analyzed by flow cytometry.The protein levels of SET7/9, glucose-regulated protein 78 (GRP78) , PERK and p-PERK in the LO2 cells of each group were observed by Western blot.RESULTS:Inhibition of SET7/9 expression reduced the apoptotic rate of arsenic-induced LO2 cells.Arsenic exposure increased the expression of SET7/9 in the LO2 cells.Arsenic exposure increased the protein levels of GRP78 and p-PERK in the LO2 cells, but decreased the protein levels of GRP78 and p-PERK after transfection with SET7/9 siRNA (P<0.05).CONCLUSION:Arsenic exposure induces hepatocyte apoptosis by increasing SET7/9 to activate ERS by PERK signaling pathway.

Effect of endoplasmic reticulum stress-induced autophagy on hepatocyte apoptosis / 中国病理生理杂志

AIM:To observe the changes of autophagy-related indexes during endoplasmic reticulum stress (ERS) induced by dithiothreitol (DTT) and its effect on apoptosis in human normal hepatocytes.METHODS:LO2 cells were treated with DTT at 2.0 mmol/L for 0, 6, 12 and 24 h to induce ERS.The expression of glucose-regulated protein 78 (GRP78) , protein kinase R-like endoplasmic reticulum kinase (PERK) , activating transcription factor 4 (ATF4) , C/EBP homologous protein (CHOP) , autophagy-related gene 12 (Atg12) , autophagy-related gene 5 (Atg5) and microtubule-associated protein 1 light chain 3 (LC3) at mRNA and protein levels was determined by real-time PCR and Western blot.The apoptosis was analyzed by flow cytometry.The formation of autophagosomes was observed under transmission electron microscope.After the LO2 cells were pretreated with rapamycin at 400 nmol/L for 1 h and treated with DTT at 2.0mmol/L for 24 h, the effect of rapamycin pretreatment on the apoptosis was analyzed by flow cytometry.RESULTS:After treatment with DTT at 2.0 mmol/L for 6, 12 and 24 h, the mRNA and protein levels of GRP78, PERK, ATF4, CHOP, Atg12, Atg5 and LC3 in the LO2 cells were significantly higher than those in 0 h group (P<0.05).At the same time, the ratio of LC3Ⅱ/LC3Ⅰwas also increased after DTT treatment (P<0.05).Observation under transmission electron microscope showed that autophagosomes were found in the LO2 cells treated with DTT for 6, 12 and 24 h.After DTT treatment for 6, 12 and 24 h, the apoptosis rate of LO2 cells was significantly higher than that in DTT 0 h group, while the apoptosis induced by DTT was significantly decreased after rapamycin pretreatment (P<0.05).CONCLUSION:ERS induces autophagy and rapamycin pretreatment alleviates the apoptosis of LO2 cells to some extent.

Screening of differential serum proteins in patients with hepatic injury resulting from coal-burning type of arsenism / 中国地方病学杂志

Objective To identify the differential serum proteins in patients with hepatic injury resulting from coal-burning type of arsenism. Methods Six serum samples were collected from patients with liver injury resulting from coal-burning type of arsenism and healthy subjects(control gruop) in endemic arsenism area. Twodimensional gel electrophoresis(2-DE) was performed to separate serum proteins, after silver staining, the differential expression of proteins were analyzed and then identified by matrix-assisted laser desorption/ionization time of flight mass spectrometry(MALDI-TOF-MS). Results The 2-DE map of serum protein patterns of patients and normal control were established successfully. The results showed that there were an average of (824 ± 31 ) spots and (782 ± 42) spots on 2-DE matching of the patients and control groups and the matching rate was 94.9%(782/824). From these two groups 49 differential protein spots were identified, of which over 3 times the difference in the expression of 30 protein spots were singled out and MALDI-TOF-MS analysis was carried out. Ten proteins were identified. Upregulated expression was observed in alpha-2-macroglobulin, B-cell receptor-associated protein, keratin 1,apolipoprotein A-I, and down-regulated expression was observed in haptoglobin, α2-heremans-schimid-glycoprotein,mitogen-activated protein kinase 4, zinc finger protein 323, ZAP-70 and SP40 in the patient group. Conclusions The well-resolved and reproducible 2-DE serum patterns of patients are established and some differentially expressed proteins are characterized. Whether these proteins of differential expression are serum markers for liver injury resulting from coal-burning type of arsenism need to be further verified.

Changes of bone morphogenetic protein-7 and inhibitory Smad expression in streptozotocin-induced diabetic nephropathy rat kidney / 生理学报

The present study was designed to observe the expressions of bone morphogenetic protein-7 (BMP-7) and inhibitory Smads in kidney of rats with diabetic nephropathy (DN), and explore the possible mechanism of DN. Male Wistar rats weighing 180-220 g were single injected with streptozocin (STZ, 55 mg/kg body weight) for 2, 4, 8 and 16 weeks to induce DN. Blood glucose, kidney weight/body weight and 24-hour urine protein in the control and DN rats were examined; the expressions of BMP-7, Smad6 and Smad7 were detected by using immunohistochemical techniques, Western blot and real-time PCR. The results showed that blood glucose and 24-hour urine protein in DN rats were higher than that in the control rats and kidney weight/body weight was also elevated in DN rats, especially in 16-week STZ-induced rats. The expressions of BMP-7 and Smad6 proteins in DN rats were elevated, while BMP-7 mRNA expression was increased 2 weeks after STZ injection and decreased 16 weeks after STZ injection. The expressions of Smad7 protein and mRNA were elevated in DN rats 2 weeks after STZ injection and decreased 16 weeks after STZ injection. In addition, the expressions of transforming growth factor-beta1 (TGF-beta1) and collagen type I (COL-I) mRNA were increased in DN rats. These results suggest in the early stage of DN, increase in BMP-7 and inhibitory Smad expression may play a role in the feedback regulation and restrain the development of DN.

Transforming growth factor-beta1 and Smad4 signaling pathway down-regulates renal extracellular matrix degradation in diabetic rats / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>To investigate the role of transforming growth factor-beta1 (TGF-beta1)/Smad4 pathway in development of renal fibrosis in streptozotocin (STZ)-induced diabetic nephropathy (DN) rats and explore its possible mechanism.</p><p><b>METHODS</b>Male Wistar rats weighing 180-220 g were divided into 5 groups: group A (normal control), group B [diabetes mellitus (DM) 2 weeks], group C (DM 4 weeks), group D (DM 8 weeks), and group E (DM 16 weeks). Except for the normal control group, other groups were induced DM by single injection of STZ (55 mg/kg) respectively. Blood glucose level, serum creatinine, and 24-hour urine protein were examined. Expressions of TGF-beta1 and Smad4 protein and mRNA in kidney were detected using immunohistochemical technique, Western blot, and real-time PCR. mRNA expressions of stromelysin-1 (MMP-3), tissue inhibitor of metalloproteinase-1 (TIMP-1), and collagen In in kidney were also detected by real-time PCR.</p><p><b>RESULTS</b>The levels of blood glucose, serum creatinine, and 24-hour urine protein in rats of group B, C, D, and E were higher than those of the control group. With the progression of renal fibrosis, the expressions of TGF-beta1 and Smad4 protein and mRNA in kidney of diabetic rats elevated. In addition, the renal MMP-3 mRNA expression diminished in diabetic rats, while TIMP-1 and collagen III mRNA increased.</p><p><b>CONCLUSIONS</b>In STZ-induced diabetic rats, the TGF-beta1/Smad4 appears to play an important role in renal fibrosis of DN. The increased expression of TGF-beta1 and Smad4 might result in the transcriptional regulation of downstream target genes of TGF-beta1/Smad4 pathway, which contributes to the progression of renal fibrosis in diabetic rats.</p>