Objective: To investigate the effects of RNA m6A demethylase ALKBH5 gene deficiency on cerebellar morphology and function in the aged mice, and to explore the role of ALKBH5 in cerebellar degeneration. Methods: Western blot was performed to detect the protein level of ALKBH5 in the cerebellum of wild-type mice of various ages. The expression of NeuN, Calbindin-D28K, MAP2, GFAP and other proteins in the cerebella of middle-aged (12-month-old) and aged (18-month-old) wild-type mice and ALKBH5^-/- mice was examined using immunohistochemistry. The balance beam test and gait analysis were performed to test the balance ability and motor coordination of the mice. Results: With aging of the mice, the expression of ALKBH5 in the cerebellum increased gradually in an age-dependent manner. In the aged mice, but not middle-aged mice, the body weight, whole brain weight and cerebellum weight of ALKBH5^-/- mice decreased by 15%, 10% and 21%, respectively (P<0.05). The expression of ALKBH5 in the Purkinje cells was much higher than that in other types of neural cells. Correspondingly, ALKBH5-deficiency caused 40% reduction in the number of Purkinje cells, as well as the length and density of neuronal dendrites in the aged mice (P<0.01). In addition, the time for the aged ALKBH5^-/- mice to pass the balance beam was 70% longer than that of the wild type mice of the same age, with unstable gaits (P<0.01). Conclusions: Gene deficiency of RNA m6A demethylase ALKBH5 causes cerebellar atrophy, Purkinje neuron loss and damage in the aged mice. These changes eventually affect mice's motor coordination and balance ability. These results suggest that imbalanced RNA m6A methylation may lead to neurodegenerative lesions in the cerebellum of mice.
Animals ; Mice ; AlkB Homolog 5, RNA Demethylase/metabolism* ; Cerebellum/metabolism* ; Methylation ; RNA/metabolism*

Cerebellar Purkinje cells (PCs) exhibit two types of discharge activities: simple spike (SS) and complex spike (CS). Previous studies found that noradrenaline (NA) can inhibit CS and bidirectionally regulate SS, but the enhancement of NA on SS is overwhelmed by the strong inhibition of excitatory molecular layer interneurons. However, the mechanism underlying the effect of NA on SS discharge frequency is not clear. Therefore, in the present study, we examined the mechanism underlying the increasing effect of NA on SS firing of PC in mouse cerebellar cortex in vivo and in cerebellar slice by cell-attached and whole-cell recording technique and pharmacological methods. GABA_A receptor was blocked by 100 µmol/L picrotoxin in the whole process. In vivo results showed that NA significantly reduced the number of spikelets of spontaneous CS and enhanced the discharge frequency of SS, but did not affect the discharge frequency of CS. In vitro experiments showed that NA reduced the number of CS spikelets and after hyperpolarization potential (AHP) induced by electrical stimulation, and increased the discharge frequency of SS. NA also reduced the amplitude of excitatory postsynaptic current (EPSC) of parallel fiber (PF)-PC and significantly increased the paired-pulse ratio (PPR). Application of yohimbine, an antagonist of α2-adrenergic receptor (AR), completely eliminated the enhancing effect of NA on SS. The α2-AR agonist, UK14304, also increased the frequency of SS. The β-AR blocker, propranolol, did not affect the effects of NA on PC. These results suggest that in the absence of GABA_A receptors, NA could attenuate the synaptic transmission of climbing fiber (CF)-PC via activating α2-AR, inhibit CS activity and reduce AHP, thus enhancing the SS discharge frequency of PC. This result suggests that NA neurons of locus coeruleus can finely regulate PC signal output by regulating CF-PC synaptic transmission.
Action Potentials/physiology* ; Animals ; Cerebellar Cortex/metabolism* ; Cerebellum/metabolism* ; Mice ; Norepinephrine/pharmacology* ; Purkinje Cells/metabolism* ; Receptors, Adrenergic, alpha-2/metabolism* ; Receptors, GABA-A/metabolism*

OBJECTIVE: The current study aimed to elucidate the effect of vanillin on behavioral changes, oxidative stress, and histopathological changes induced by potassium bromate (KBrO3), an environmental pollutant, in the cerebellum of adult mice. METHODS: The animals were divided into four groups: group 1 served as a control, group 2 received KBrO3, group 3 received KBrO3 and vanillin, and group 4 received only vanillin. We then measured behavioral changes, oxidative stress, and molecular and histological changes in the cerebellum. RESULTS: We observed significant behavioral changes in KBrO3-exposed mice. When investigating redox homeostasis in the cerebellum, we found that mice treated with KBrO3 had increased lipid peroxidation and protein oxidation in the cerebellum. These effects were accompanied by decreased Na+-K+ and Mg2+ ATPase activity and antioxidant enzyme gene expression when compared to the control group. Additionally, there was a significant increase in cytokine gene expression in KBrO3-treated mice. Microscopy revealed that KBrO3 intoxication resulted in numerous degenerative changes in the cerebellum that were substantially ameliorated by vanillin supplementation. Co-administration of vanillin blocked the biochemical and molecular anomalies induced by KBrO3. CONCLUSION Our results demonstrate that vanillin is a potential therapeutic agent for oxidative stress associated with neurodegenerative diseases.
Animals ; Antioxidants ; metabolism ; Behavior, Animal ; drug effects ; Benzaldehydes ; pharmacology ; Bromates ; toxicity ; Cerebellum ; drug effects ; metabolism ; pathology ; Cytokines ; genetics ; metabolism ; Environmental Pollutants ; toxicity ; Gene Expression ; drug effects ; Lipid Peroxidation ; drug effects ; Mice ; Oxidative Stress ; drug effects ; Rotarod Performance Test

Attention deficit hyperactivity disorder (ADHD) is a common childhood neuropsychiatric disorder that has been linked to the dopaminergic system. This study aimed to investigate the effects of regulation of the dopamine D4 receptor (DRD4) on functional brain activity during the resting state in ADHD children using the methods of regional homogeneity (ReHo) and functional connectivity (FC). Resting-state functional magnetic resonance imaging data were analyzed in 49 children with ADHD. All participants were classified as either carriers of the DRD4 4-repeat/4-repeat (4R/4R) allele (n = 30) or the DRD4 2-repeat (2R) allele (n = 19). The results showed that participants with the DRD4 2R allele had decreased ReHo bilaterally in the posterior lobes of the cerebellum, while ReHo was increased in the left angular gyrus. Compared with participants carrying the DRD4 4R/4R allele, those with the DRD4 2R allele showed decreased FC to the left angular gyrus in the left striatum, right inferior frontal gyrus, and bilateral lobes of the cerebellum. The increased FC regions included the left superior frontal gyrus, medial frontal gyrus, and rectus gyrus. These data suggest that the DRD4 polymorphisms are associated with localized brain activity and specific functional connections, including abnormality in the frontal-striatal-cerebellar loop. Our study not only enhances the understanding of the correlation between the cerebellar lobes and ADHD, but also provides an imaging basis for explaining the neural mechanisms underlying ADHD in children.
Attention Deficit Disorder with Hyperactivity ; diagnostic imaging ; genetics ; pathology ; Brain ; diagnostic imaging ; Cerebellum ; diagnostic imaging ; Child ; Corpus Striatum ; diagnostic imaging ; Female ; Frontal Lobe ; diagnostic imaging ; Genotype ; Humans ; Image Processing, Computer-Assisted ; Magnetic Resonance Imaging ; Male ; Minisatellite Repeats ; genetics ; Neural Pathways ; diagnostic imaging ; Oxygen ; blood ; Receptors, Dopamine D4 ; genetics ; metabolism ; Rest

OBJECTIVETo investigate acrylamide (ACR)-induced subacute neurotoxic effects on the central nervous system (CNS) at the synapse level in rats.

METHODSThirty-six Sprague Dawley (SD) rats were randomized into three groups, (1) a 30 mg/kg ACR-treated group, (2) a 50 mg/kg ACR-treated group, and (3) a normal saline (NS)-treated control group. Body weight and neurological changes were recorded each day. At the end of the test, cerebral cortex and cerebellum tissues were harvested and viewed using light and electron microscopy. Additionally, the expression of Synapsin I and P-Synapsin I in the cerebral cortex and cerebellum were investigated.

RESULTSThe 50 mg/kg ACR-treated rats showed a significant reduction in body weight compared with untreated individuals (P < 0.05). Rats exposed to ACR showed a significant increase in gait scores compared with the NS control group (P < 0.05). Histological examination indicated neuronal structural damage in the 50 mg/kg ACR treatment group. The active zone distance (AZD) and the nearest neighbor distance (NND) of synaptic vesicles in the cerebral cortex and cerebellum were increased in both the 30 mg/kg and 50 mg/kg ACR treatment groups. The ratio of the distribution of synaptic vesicles in the readily releasable pool (RRP) was decreased. Furthermore, the expression levels of Synapsin I and P-Synapsin I in the cerebral cortex and cerebellum were decreased in both the 30 mg/kg and 50 mg/kg ACR treatment groups.

CONCLUSIONSubacute ACR exposure contributes to neuropathy in the rat CNS. Functional damage of synaptic proteins and vesicles may be a mechanism of ACR neurotoxicity.

Acrylamide ; toxicity ; Animals ; Cerebellum ; cytology ; drug effects ; Cerebral Cortex ; cytology ; drug effects ; Drug Administration Schedule ; Gait ; Gene Expression Regulation ; drug effects ; Male ; Neurons ; drug effects ; Neurotoxicity Syndromes ; pathology ; Rats ; Rats, Sprague-Dawley ; Synapses ; drug effects ; Synapsins ; genetics ; metabolism ; Synaptic Vesicles ; drug effects ; physiology ; Weight Loss ; drug effects

BACKGROUNDThe pathophysiology of poststroke depression (PSD) remains elusive because of its proposed multifactorial nature. Accumulating evidence suggests that brain-derived neurotrophic factor (BDNF) plays a key role in the pathophysiology of depression and PSD. And the cerebellar dysfunction may be important in the etiology of depression; it is not clear whether it also has a major effect on the risk of PSD. This study aimed to explore the expression of BDNF and high-affinity receptors tyrosine kinase B (TrkB) in the cerebellum of rats with PSD.

METHODSThe rat models with focal cerebral ischemic were made using a thread embolization method. PSD rat models were established with comprehensive separate breeding and unpredicted chronic mild stress (UCMS) on this basis. A normal control group, depression group, and a stroke group were used to compare with the PSD group. Thirteen rats were used in each group. Immunohistochemistry and reverse transcription-polymerase chain reaction (RT-PCR) for detecting the expression of BDNF and TrkB protein and mRNA in the cerebellum were used at the 29 th day following the UCMS.

RESULTSCompared with the normal control group and the stroke group, the number of BDNF immunoreactive (IR) positive neurons was less in the PSD group (P < 0.05). Furthermore, the number of TrkB IR positive cells was significantly less in the PSD group than that in the normal control group (P < 0.05). The gene expression of BDNF and TrkB in the cerebellum of PSD rats also decreased compared to the normal control group (P < 0.05).

CONCLUSIONSThese findings suggested a possible association between expression of BDNF and TrkB in the cerebellum and the pathogenesis of PSD.

Animals ; Brain-Derived Neurotrophic Factor ; metabolism ; Cerebellum ; metabolism ; Depression ; etiology ; metabolism ; Female ; Protein-Tyrosine Kinases ; metabolism ; Rats ; Rats, Sprague-Dawley ; Stroke ; complications

OBJECTIVETo study the toxicity of methomyl to acetylcholinesterase (AChE) in different regions.

METHODSThe optimal temperature and time for measurement of AChE activity were determined in vitro. The dose- and time-response relationships of methomyl with AChE activity in human erythrocyte membrane, rat erythrocyte membrane, cortical synapses, cerebellar synapses, hippocampal synapses, and striatal synapses were evaluated. The half maximal inhibitory concentration (IC50) and bimolecular rate constant (K) of methomyl for AChE activity in different regions were calculated, and the type of inhibition of AChE activity by methomyl was determined.

RESULTSAChE achieved the maximum activity at 370 °C, and the optimal time to determine initial reaction velocity was 0-17 min. There were dose- and time-response relationships between methomyl and AChE activity in the erythrocyte membrane and various brain areas. The IC50 value of methomyl for AChE activity in human erythrocyte membrane was higher than that in rat erythrocyte membrane, while the Ki value of methomyl for AChE activity in rat erythrocyte membrane was higher than that in human erythrocyte membrane. Among synapses in various brain areas, the striatum had the highest IC50 value, followed by the cerebellum, cerebral cortex, and hippocampus, while the cerebral cortex had the highest Ki value, followed by the hippocampus, striatum, and cerebellum. Lineweaver-Burk diagram demonstrated that with increasing concentration of methomyl, the maximum reaction velocity (Vmax) of AChE decreased, and the Michaelis constant (Km) remained the same.

CONCLUSIONMethomyl is a reversible non-competitive inhibitor of AChE. AChE of rat erythrocyte membrane is more sensitive to methomyl than that of human erythrocyte membrane; the cerebral cortical synapses have the most sensitive AChE to methomyl among synapses in various brain areas.

Acetylcholinesterase ; metabolism ; Animals ; Cerebellum ; drug effects ; Cerebral Cortex ; drug effects ; Erythrocyte Membrane ; drug effects ; enzymology ; Hippocampus ; drug effects ; Humans ; Inhibitory Concentration 50 ; Methomyl ; toxicity ; Rats ; Synapses ; drug effects ; Toxicity Tests

OBJECTIVETo identify novel lncRNAs involved in cerebellar neurogenesis using neuronal specific Nbs1-deficient (Nbs1(CNS-del)) mouse model.

METHODSMicroarray analysis was performed to identify differentially expressed lncRNAs between Nbs1(CNS-ctr) and Nbs1(CNS-del) mice. Expression profiles of lncRNA Gm15577 and coding gene Negr1 in mice, primary cerebellar culture and cell lines were measured using RT-qPCR. Subcellular fractionation was performed to determine the subcellular localization of Gm15577.

RESULTSGm15577 was specifically expressed in mice cerebellum in a developmentally regulated manner, which could be abolished upon Nbs1-deficiency. Gm15577 was located in the intronic region of Negr1 in a reversed orientation. Gm15577 modulated the RNA expression of Negr1, Shh and β-catenin. NEGR1 had a distinct expression pattern between normal and medulloblastoma patients.

CONCLUSIONGm15577 may modulate cerebellar granule cell proliferation and differentiation by targeting Negr1, and their dysfunctions or abnormal expression may be related to tumorigenesis of medulloblastoma.

Animals ; Cell Differentiation ; Cell Proliferation ; Cell Transformation, Neoplastic ; Cerebellar Neoplasms ; pathology ; Cerebellum ; cytology ; physiology ; Disease Models, Animal ; Humans ; Introns ; Medulloblastoma ; pathology ; Mice ; Mice, Knockout ; Neurogenesis ; Neurons ; physiology ; RNA, Long Noncoding ; metabolism

Mitochondrial calcium uniporter (MCU) is a conserved Ca(2+) transporter at mitochondrial in eukaryotic cells. However, the role of MCU protein in oxidative stress-induced cell death remains unclear. Here, we showed that ectopically expressed MCU is mitochondrial localized in both HeLa and primary cerebellar granule neurons (CGNs). Knockdown of endogenous MCU decreases mitochondrial Ca(2+) uptake following histamine stimulation and attenuates cell death induced by oxidative stress in both HeLa cells and CGNs. We also found MCU interacts with VDAC1 and mediates VDAC1 overexpression-induced cell death in CGNs. This finding demonstrates that MCU-VDAC1 complex regulates mitochondrial Ca(2+) uptake and oxidative stress-induced apoptosis, which might represent therapeutic targets for oxidative stress related diseases.
Animals ; Apoptosis ; Biological Transport ; Calcium ; metabolism ; Calcium Channels ; metabolism ; Cerebellum ; cytology ; HeLa Cells ; Humans ; Mice ; Mitochondria ; metabolism ; Neurons ; cytology ; metabolism ; Oxidative Stress ; Voltage-Dependent Anion Channels ; metabolism

OBJECTIVE: To observe the expression pattern of caspase-3 and HCLS1-associated protein X-1 (HAX-1) at different time after cerebral contusion in rat, and explore the new method for estimating the injury interval. METHODS: The cerebral contusion model was established using adult SD male rats. Then the rats were randomly allocated into 8 groups: 2 h, 6 h, 12 h, 1 d, 3 d, and 7 d after cerebral contusion, sham-operation and normal control. Expression of caspase-3 and HAX-1 protein after cerebral contusion in rat was detected by Western blotting. Laser scanning confocal microscope was used to observe the number of HAX-1 positive cells and TUNEL-stained cells after cerebral contusion. RESULTS: The expression of caspase-3 increased parallelly with the time after cerebral contusion and reached the peak value on 3 d. The expression of caspase-3 decreased gradually and still maintained a high level expression on 7 d (P < 0.05). The expression of HAX-1 positive cell went up after injury, and reached the peak value at 6 h (P < 0.05), then turned down gradually after 12 h and went out of detection after 3 d. The number of TUNEL-stained cells increased obviously at 2 h and reached the peak value on 3 d. The number of TUNEL-stained apoptotic cells decreased gradually and still maintained a high level expression on 7 d (P < 0.05). CONCLUSION The expression of caspase-3 and HAX-1 after cerebral contusion has time sequential regularity, which may provide new evidence for forensic diagnosis of cerebral contusion interval.
Animals ; Blotting, Western ; Brain Injuries/pathology* ; Carrier Proteins/metabolism* ; Caspase 3/metabolism* ; Cerebellum/pathology* ; In Situ Nick-End Labeling ; Intracellular Signaling Peptides and Proteins ; Male ; Rats ; Rats, Sprague-Dawley