Objective: To investigate the effect and mechanism of miR-96-5p on apoptosis of PC12 cells induced by maltol aluminum. Methods: In January 2021, PC12 cells at logarithmic growth phase were divided into blank control group and low, medium and high dose group. Cells in each group were treated with 0, 100, 200 and 400 μmol/L maltol aluminum for 24 hours respectively. Cells were collected and cell apoptosis rates were detected by flow cytometry, miR-96-5p and insulin receptor substrate 1 (IRS1) mRNA expressions were detected by qRT-PCR, and the protein expression levels of cysteine protease 3 (Caspase3) 、activated cysteine protease 3 (Cleaved-caspase3) 、IRS1、phosphorylated protein kinase B (p-AKT) and phosphorylated glucose synthesis kinase 3β (p-GSK3β) were detected by western blotting. The target binding relationship between miR-96-5p and IRS1 was detected by double luciferase reporter gene experiment. The miR-96-5p inhibitor cells and negative control cells were constructed after transfecting PC12 cells with miR-96-5p inhibitor for 24 hours. The cells were divided into blank control group, negative control group, aluminum exposure group, aluminum exposure+negative control group, aluminum exposure+miR-96-5p inhibition group, and miR-96-5p inhibition group. After transfecting PC12 cells with miR-96-5p inhibition and IRS1 siRNA for 24 h, the cells were divided into aluminum exposure+miR-96-5p inhibition+negative control group and aluminum exposure+miR-96-5p inhibition+IRS1 inhibition group. The control group was cultured in complete culture medium, and cells in the aluminum exposure group were treated with 200 μmol/L maltol aluminum for 24 hours. Cells in each group were collected and the apoptosis rate, miR-96-5p and IRS1 mRNA expression levels, as well as protein expression levels of Caspase3, Cleaved-caspase3, IRS1, p-AKT, and p-GSK3β were measured. Results: After 24 hours of exposure, compared with blank control group and low-dose group, the apoptosis rates, relative expressions of Caspase3 and Cleaved-caspase3 proteins, and relative expressions of miR-96-5p in the medium and high-dose groups of PC12 cells were significantly increased, while the relative expression levels of IRS1 mRNA, IRS1, p-AKT and p-GSK3β proteins were significantly decreased (P<0.05). Targetscan prediction and double luciferase report experiment both proved that IRS1 was a direct target gene of miR-96-5p. In the transfection experiment, compared with the aluminum exposure group, the apoptosis rate, the relative expressions of Caspase3 and Cleaved-caspase3 proteins, the relative expression of miR-96-5p in the aluminum exposure+miR-96-5p inhibition group were significantly decreased, while the relative expression levels of IRS1 mRNA and IRS1, p-AKT and p-GSK3β proteins were significantly increased (P<0.05). In the IRS1 low expression experiment, compared with the aluminum exposure+miR-96-5p inhibition+negative control group, the apoptosis rate, the relative expressions of Caspase3 and Cleaved-caspase3 proteins in the aluminum exposure+miR-96-5p inhibition+IRS1 inhibition group were significantly increased, while the relative expression levels of IRS1 mRNA and IRS1, p-AKT and p-GSK3β proteins were significantly decreased (P<0.05) . Conclusion: The increased expression of miR-96-5p and the targeted inhibition of IRS1 may be one of the mechanisms of apoptosis of PC12 cells induced by maltol aluminum exposure.
Animals ; Rats ; Aluminum/toxicity* ; Apoptosis ; Cell Proliferation ; Glycogen Synthase Kinase 3 beta/metabolism* ; Insulin Receptor Substrate Proteins/metabolism* ; MicroRNAs/metabolism* ; PC12 Cells ; Proto-Oncogene Proteins c-akt/metabolism* ; RNA, Messenger

Aluminum is one of the most abundant elements on earth. Aluminum compounds are widely used in food additives, antacids, cooking utensils and so on. Human exposure to aluminum is mainly through diet and drinking water, while excessive intake of aluminum can accumulate in tissues and cause toxic reactions. In the central nervous system, aluminum exposure is closely related to a series of nervous system diseases such as Alzheimer's disease, Parkinson's disease and amyotrophic lateral sclerosis. Epigenetic modification refers to the regulation of gene expression without changing the DNA sequence, and its regulatory disorders can lead to abnormalities and diseases of the central nervous system. This paper describes the regulation of epigenetics and its components, including DNA methylation, histone modification and non-coding RNA, in aluminum-induced neurotoxicity, in order to provide insights into the epigenetic mechanism of aluminum-induced neurotoxicity.
Aluminum/toxicity* ; Alzheimer Disease ; Cooking ; DNA Methylation ; Epigenesis, Genetic ; Humans

Aluminum (Al) is the most abundant metal element in the earth's crust. On acid soils, at pH 5.5 or lower, part of insoluble Al-containing minerals become solubilized into soil solution, with resultant highly toxic effects on plant growth and development. Nevertheless, some plants have developed Al-tolerance mechanisms that enable them to counteract this Al toxicity. One such well-documented mechanism is the Al-induced secretion of organic acid anions, including citrate, malate, and oxalate, from plant roots. Once secreted, these anions chelate external Al ions, thus protecting the secreting plant from Al toxicity. Genes encoding the citrate and malate transporters responsible for secretion have been identified and characterized, and accumulating evidence indicates that regulation of the expression of these transporter genes is critical for plant Al tolerance. In this review, we outline the recent history of research into plant Al-tolerance mechanisms, with special emphasis on the physiology of Al-induced secretion of organic acid anions from plant roots. In particular, we summarize the identification of genes encoding organic acid transporters and review current understanding of genes regulating organic acid secretion. We also discuss the possible signaling pathways regulating the expression of organic acid transporter genes.
Aluminum ; toxicity ; Anions ; Biological Transport ; drug effects ; Citric Acid ; metabolism ; Malates ; metabolism ; Oxalic Acid ; metabolism ; Plant Roots ; drug effects ; metabolism ; Signal Transduction ; physiology

In this study, we investigated the effects of chronic aluminum (Al) exposure for 10 weeks on cell proliferation and neuroblast differentiation in the hippocampus of type 2 diabetic rats. Six-week-old Zucker diabetic fatty (ZDF) and Zucker lean control (ZLC) rats were selected and randomly divided into Al- and non-Al-groups. Al was administered via drinking water for 10 weeks, after which the animals were sacrificed at 16 weeks of age. ZDF rats in both Al- and non-Al-groups showed increases in body weight and blood glucose levels compared to ZLC rats. Al exposure did not significantly affect body weight, blood glucose levels or pancreatic β-cells and morphology of the pancreas in either ZLC or ZDF rats. However, exposure to Al reduced cell proliferation and neuroblast differentiation in both ZLC and ZDF rats. Exposure to Al resulted in poor development of the dendritic processes of neuroblasts in both ZLC and ZDF rats. Furthermore, onset and continuation of diabetes reduced cell proliferation and neuroblast differentiation, and Al exposure amplified reduction of these parameters. These results suggest that Al exposure via drinking water aggravates the impairment in hippocampal neurogenesis that is typically observed in type 2 diabetic animals.
Aluminum/*toxicity ; Animals ; Blood Glucose/analysis ; Cell Differentiation/drug effects ; Cell Proliferation/drug effects ; Diabetes Mellitus, Experimental/pathology ; Diabetes Mellitus, Type 2/*pathology ; Disease Models, Animal ; Hippocampus/*drug effects ; Neurogenesis/*drug effects ; Random Allocation ; Rats, Zucker

OBJECTIVETo explore the role of RAS/PI3K pathway in the impairment of long-term potentiation (LTP) induced by acute aluminum (Al) treatment in rats in vivo.

METHODSFirst, different dosages of aluminum-maltolate complex [Al(mal)3] were given to rats via acute intracerebroventricular (i.c.v.) injection. Following Al exposure, the RAS activity of rat hippocampus were detected by ELISA assay after the hippocampal LTP recording by field potentiation technique in vivo. Second, the antagonism on the aluminum-induced suppression of hippocampal LTP was observed after the treatment of the RAS activator epidermal growth factor (EGF). Finally, the antagonism on the downstream molecules (PKB activity and the phosphorylation of GluR1 S831 and S845) were tested by ELISA and West-blot assays at the same time.

RESULTSWith the increasing aluminum dosage, a gradually decreasing in RAS activity of the rat hippocampus was produced after a gradually suppressing on LTP. The aluminum-induced early suppression of hippocampal LTP was antagonized by the RAS activator epidermal growth factor (EGF). And the EGF treatment produced changes similar to those observed for LTP between the groups on PKB activity as well as the phosphorylation of GluR1 S831 and S845.

CONCLUSIONThe RAS→PI3K/PKB→GluR1 S831 and S845 signal transduction pathway may be involved in the inhibition of hippocampal LTP by aluminum exposure in rats. However, the mechanisms underlying this observation need further investigation.

Aluminum ; toxicity ; Animals ; Epidermal Growth Factor ; metabolism ; Hippocampus ; drug effects ; metabolism ; Injections, Intraventricular ; Long-Term Potentiation ; drug effects ; Male ; Phosphatidylinositol 3-Kinases ; metabolism ; Phosphorylation ; drug effects ; Proto-Oncogene Proteins c-akt ; metabolism ; Random Allocation ; Rats ; Receptors, AMPA ; metabolism ; Signal Transduction ; drug effects ; ras Proteins ; metabolism

OBJECTIVEIn this research, we have observed changes of PHF8、H3K9me2、BDNF, and their regulatory roles in changing the amplitude value of LTP in hippocampus due to aluminum exposure so that we can discuss the impact on the learning and memory that caused by chronic aluminum exposure.

METHODSForty healthy SPF grade SD male rats were randomly divided into four groups by weight, including control group and low, medium, high dose aluminum exposed group, each group had 10 rats. The exposed rats drank water containing different doses of aluminum chloride (AlCl3) (2、12、72 mg/kg Al(3+)) for 90 d. We measured LTP in hippocampus by electrophysiological grapier and detected the expression of PHF8、H3K9me2、BDNF by western-blot.

RESULTSElectrophysiological measurements shows that compared with that of control group, the average of fEPSPs was decreased at different time points in all exposed groups (P<0.01) . The results of western-bolt test demonstrated that the expression of PHF8 in the exposed groups were significantly lower than those of control group (P<0.01) . And the expression the of H3K9me2 of medium and high dose groups were significantly higher than control group (P<0.05) . While the expression of BDNF of medium and high dose groups were decreased compared with the control group (P<0.05) .

CONCLUSIONChronic aluminum exposure can reduce the LTP via the route of PHF8-H3K9me2-BDNF in the hippocampus of rats, which then may impair the ability of learning and memory.

Aluminum ; toxicity ; Aluminum Compounds ; toxicity ; Animals ; Brain-Derived Neurotrophic Factor ; metabolism ; Chlorides ; toxicity ; Hippocampus ; drug effects ; metabolism ; Histone Demethylases ; metabolism ; Learning ; drug effects ; Long-Term Potentiation ; drug effects ; Male ; Memory ; drug effects ; Pilot Projects ; Rats ; Rats, Sprague-Dawley ; Transcription Factors ; metabolism

OBJECTIVETo investigate the effect of aluminum exposure on neuronal apoptosis of rats hippocampus and the correlation of and synaptic plasticity.

METHODSThere were 40 SPF grade SD rats which were randomly divided into four groups: the control group, the low dose group, the medium dose group and the high dose group, 10 rats in each group. The rats were daily gavaged with aluminum lactate for 30 days. The hippocampal fEPSPs in rat was measured by electrophysiological grapher and the neuronal apoptosis in hippocampus was detected by Flow cytometer. In addition, the relative expression of gene which includes caspase-3, 8, 9 was measured by Real-time PCR.

RESULTSCompared to the control group, the average of fEPSPs which after HFS 10, 20, 30, 40, 50, 60 min was decreased at different time point in the low dose group, the medium dose group and the high dose group (P < 0.05). Compared with the control group, the rate of apoptosis was significantly increased in the medium dose group and the high dose group (P < 0.05). Compared to the control group, the relative expression of caspase-3 in the medium dose group and the high dose group was significantly increased in Real-time PCR (P < 0.05), and the relative expression of caspase-8 in the high dose group was significantly increased (P < 0.05).

CONCLUSIONAluminum exposure may induced neuronal apoptosis in rats, and then affect hippocampal synaptic plasticity.

Aluminum ; toxicity ; Aluminum Compounds ; toxicity ; Animals ; Apoptosis ; Caspase 3 ; metabolism ; Caspase 8 ; metabolism ; Hippocampus ; cytology ; drug effects ; Lactates ; toxicity ; Neuronal Plasticity ; drug effects ; Neurons ; cytology ; drug effects ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo explore the role of P53 phosphorylation in neuron apoptosis of rats by chronic aluminum exposure.

METHODSA total of male 40 SD rats were divided randomly into 4 groups (n = 10/dose), the exposed groups were fed with normal diet with different concentration of AlCl3 · 6H2O for 6 months respectively. The dosage of low, middle and high groups were 10.73, 107.33, 1073.33 mg/kg in sequence. The control group received normal diet. The neuron apoptosis was measured by method of Tunel. The expressions of P53 and pP53-ser15 protein in the cortex were detected by Western-blot.

RESULTSTunel staining showed that the low, middle and high group rats had increased apoptosis rate than control group (P < 0.01). Western-blot test demonstrated that the expression of P53 protein in the cortex of high group rats were significantly higher than the control and low groups (P < 0.05). The expression of pP53-ser15 protein in the cortex of middle and high group rats were also higher than the control and low groups (P < 0.05).

CONCLUSIONChronic aluminum exposure can lead to over expression of P53 and pP53-ser15 protein in cerebral cortex, which maybe one of the most important mechanisms of neuron apoptosis induced by AlCl3.

Aluminum ; toxicity ; Aluminum Compounds ; toxicity ; Animals ; Apoptosis ; Cerebral Cortex ; metabolism ; Chlorides ; toxicity ; Male ; Neurons ; cytology ; drug effects ; Phosphorylation ; Rats ; Rats, Sprague-Dawley ; Tumor Suppressor Protein p53 ; metabolism

OBJECTIVETo explore the effects of exposure to aluminum (Al) on long-term potentiation (LTP) and AMPA receptor subunits in rats in vivo.

METHODSDifferent dosages of aluminum-maltolate complex [Al(mal)3] were given to rats via acute intracerebroventricular (i.c.v.) injection and subchronic intraperitoneal (i.p.) injection. Following Al exposure, the hippocampal LTP were recorded by field potentiation technique in vivo and the expression of AMPAR subunit proteins (GluR1 and GluR2) in both total and membrane-enriched extracts from the CA1 area of rat hippocampus were detected by Western blot assay.

RESULTSAcute Al treatment produced dose-dependent suppression of LTP in the rat hippocampus and dose-dependent decreases of GluR1 and GluR2 in membrane extracts; however, no similar changes were found in the total cell extracts, which suggests decreased trafficking of AMPA receptor subunits from intracellular pools to synaptic sites in the hippocampus. The dose-dependent suppressive effects on LTP and the expression of AMPA receptor subunits both in the membrane and in total extracts were found after subchronic Al treatment, indicating a decrease in AMPA receptor subunit trafficking from intracellular pools to synaptic sites and an additional reduction in the expression of the subunits.

CONCLUSIONAl(mal)3 obviously and dose-dependently suppressed LTP in the rat hippocampal CA1 region in vivo, and this suppression may be related to both trafficking and decreases in the expression of AMPA receptor subunit proteins. However, the mechanisms underlying these observations need further investigation.

Aluminum ; toxicity ; Animals ; Down-Regulation ; drug effects ; genetics ; physiology ; Hippocampus ; drug effects ; physiology ; Long-Term Potentiation ; drug effects ; genetics ; physiology ; Male ; Protein Transport ; drug effects ; genetics ; physiology ; Random Allocation ; Rats ; Receptors, AMPA ; antagonists & inhibitors ; genetics ; metabolism ; Toxicity Tests, Acute ; Toxicity Tests, Subchronic

OBJECTIVETo investigate the effect of aluminum trichloride on the abnormal phosphorylation of tau protein in SH-SY5Y cells.

METHODSSH-SY5Y cells were assigned to control group and aluminum trichloride exposure groups (200, 400, and 800 µmol/L Al(3+)). The cell morphology was observed after 48 hours of exposure; the cell viability was measured by CCK-8 assay; total protein was extracted from the cells, and the expression of phospho-tau (p-tau) 181, 231, 262, and 396 and tau 5 was measured by Western blot.

RESULTSAs the Al(3+) concentration rose, the number of living SH-SY5Y cells decreased, and the synapses of the cells retracted. The viability of cells exposed to 800 µmol/L Al(3+) was significantly lower than that of the control group (P < 0.05). The 200, 400, and 800 µmol/L Al(3+) exposure groups showed significantly higher expression of p-tau 181, 231, and 396 and tau5 than the control group (P < 0.05), and the 800 µmol/L Al(3+) exposure group showed significantly higher expression of p-tau 262 than the control group (P < 0.05).

CONCLUSIONUnder the present experimental conditions, aluminum trichloride has toxic effect on SH-SY5Y cells and can lead to abnormal expression of p-tau 181, 231, and 396 and tau 5 at low Al(3+) concentration.

Aluminum Compounds ; toxicity ; Cell Line, Tumor ; Cell Survival ; drug effects ; Chlorides ; toxicity ; Humans ; Phosphorylation ; tau Proteins ; metabolism